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Passive smoking acutely affects the microcirculation in healthy non-smokers
Journal Pre-proof Passive smoking acutely affects the microcirculation in healthy non-smokers
V. Linardatou, E. Karatzanos, N. Panagopoulou, D. Delis, C. Kourek, N. Rovina, S. Nanas, I. Vasileiadis PII:
S0026-2862(19)30075-5
DOI:
https://doi.org/10.1016/j.mvr.2019.103932
Reference:
YMVRE 103932
To appear in:
Microvascular Research
Received date:
4 April 2019
Revised date:
31 August 2019
Accepted date:
26 September 2019
Please cite this article as: V. Linardatou, E. Karatzanos, N. Panagopoulou, et al., Passive smoking acutely affects the microcirculation in healthy non-smokers, Microvascular Research(2019), https://doi.org/10.1016/j.mvr.2019.103932
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© 2019 Published by Elsevier.
Journal Pre-proof
Passive smoking acutely affects the microcirculation in healthy non-smokers V. Linardatou1,2, E. Karatzanos1, N. Panagopoulou1, D. Delis1, C. Kourek1, N. Rovina3, S. Nanas1, I. Vasileiadis3 1
Clinical Ergospirometry Exercise and Rehabilitation Laboratory, Evaggelismos Hospital, School of
Medicine, National and Kapodistrian University of Athens, Athens, Greece 2
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Department of Oncology, General Hospital 'G. Gennimatas', Athens, Greece. ICU, 1stDept of Respiratory Medicine, 'Sotiria' Hospital, School of Medicine, National and Kapodistrian
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University of Athens, Athens, Greece
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Corresponding author:
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IoannisVasileiadis, MD
Assistant Professor of Internal Medicine and Critical Care
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Intensive Care Unit, First Department of Respiratory Medicine, National and Kapodistrian University of Athens, Sotiria Hospital, 152 Mesogeion Ave, 115 27, Athens, Greece
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Email: [email protected], [email protected] Tel: +30 6977644866, +30 210 7763725
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Fax: +30 210 7781250
Journal Pre-proof ABSTRACT Objective: Acute effects of passive smoking on microcirculation have not been sufficiently studied. The aim of the present study was to detect microcirculatory alterations in healthy nonsmokers after passive exposure to cigarette smoke, utilizing the Near Infrared Spectroscopy method combined with the vascular occlusion technique. Methods: Sixteen (9 females, age: 34±9 years) non-smoking, healthy volunteers were exposed
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to passive smoking for 30min in a temperature-controlled environment. Smoke concentration
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was monitored with a real-time particle counter. The following microcirculatory parameters were
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estimated: baseline tissue oxygen saturation (StO2); StO2 decrement after vascular occlusion
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(indicating the oxygen consumption rate); StO2incremental response after vascular occlusion release (reperfusion rate); the time period where the StO2 signal returns to the baseline values
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after the hyperemic response.
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Results: Baseline StO2 (79.6±6.4 vs. 79±8%, p=0.53) as well as the time needed for StO2 to
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return to baseline levels (138.2±26.5 vs. 142.1±34.6 sec, p=0.64) did not significantly differ before vs. after passive smoking exposure. Oxygen consumption rate decreased after 30min
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exposure to passive smoking (from 12.8±4.2 to11.3±2.8 %/min, p=0.04); Reperfusion rate also significantly decreased (from 5.6±1.8 to 5±1.7 %/sec, p=0.04). Conclusions: Our results suggest that acute exposure to passive smoking delays peripheral tissue oxygen consumption and adversely affects microcirculatory responsiveness after stagnant ischemia in healthy non-smokers. Key words: microcirculation; near-infrared spectroscopy; passive smoking; vascular reactivity; endothelium dysfunction
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Abbreviations Area Under the Curve
CO
Carbon Monoxide
COHb
Carboxyhemoglobin
FMD
Flow Mediated Dilation
NIRS
Near Infrared Spectroscopy Tissue Oxygen Saturation
THI
Tissue hemoglobin index
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StO2
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AUC
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1. INTRODUCTION Passive smoking is the exposition, especially of non-smokers, to second-hand smoke, that comes from the combustion of tobacco and the exhalation of active smokers (Henriksson et al., 2014; Sureda et al., 2013). Smoke inhaled by passive smoking contains thousands of toxic chemicals, including particulate matters (Raupach et al., 2006; Sureda et al., 2013). Sidestream smoke can be more toxic than the mainstream smoke and its toxicity has been proved greater
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than the sum of toxicities of its constituents (Schick and Glantz, 2005; Torres et al., 2018).
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Second-hand smoke toxic exposition has been held responsible for hundreds of thousands
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of deaths worldwide (Torres et al., 2018), a significant proportion of which has been attributed to
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cardiovascular disease (Morris et al, 2015).
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Previous studies have demonstrated the harmful effect of passive smoking on the cardiovascular system. The proposed mechanisms, that probably mediate this harmful effect, are
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platelet dysfunction, endothelial dysfunction, increased inflammation and oxidative stress,
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mitochondrial damage and decreased energy metabolism (Barnoya and Glantz, 2005).
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Nevertheless, the impact of passive smoking specifically on microcirculation has not been extensively studied. Few existing studies are mainly concerned with assessing the effect of passive smoking on the velocity of blood flow in specific capillaries (Henriksson et al., 2014), not providing evidence for the entire microvascular effect, and the flow mediated dilation (FMD), a broad index of endothelial dysfunction (Pinnamaneni et al., 2014). There are no data regarding the acute effect of passive smoking on tissue oxygenation, oxygen consumption and the microvascular reactivity, which altogether evaluate the functional interaction between microcirculatory alterations and tissue oxidative metabolism. This information is provided by Near Infrared Spectroscopy (NIRS) with the vascular occlusion technique. 4
Journal Pre-proof NIRS has been proved a reliable research and clinical tool which uses the principles of light spectroscopy to measure the percentage saturation of hemoglobin with oxygen in all tissue vascular compartments (arterial, capillary, venous), i.e. the tissue oxygen saturation (StO2) (Bale et al., 2016; Romagnoli et al., 2013). StO2 values indicate the balance between oxygen supply and demand. StO2 decline during vascular occlusion corresponds to the tissue oxygen consumption rate, reflecting the oxidative metabolism of the underlying skeletal muscles at rest
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(Gerovasili et al., 2010; Lima and Bakker, 2011; Romagnoli et al., 2013). NIRS derived upslope
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at the reperfusion phase (tissue reperfusion/reoxygenation rate) as well as the under the curve
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area (AUC) are indices of microvascular reactivity; they have been used in various patient
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populations and healthy individuals (Donati et al., 2016; Dimopoulos et al., 2013; Soares and Murias, 2018), where, faster StO2 upslope at the reperfusion phase and greater AUC are
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associated with improved microvascular responsiveness. NIRS methodology has already been
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used to assess the acute effect of active smoking on microcirculation (Siafaka et al., 2007).
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The aim of our study was to evaluate the acute effects of passive smoking on NIRS derived microcirculatory indices, in healthy adults not routinely exposed to tobacco smoke. We
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hypothesized that passive smoking would adversely affect microcirculatory parameters, assessed by NIRS, in healthy non-smokers, i.e., decrease the oxygen consumption rate and the reperfusion rate.
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Journal Pre-proof 2. MATERIALS AND METHODS
2.1 Study population Sixteen nonsmoking, healthy volunteers participated in the present study, which took place at Evaggelismos hospital. The study protocol was approved by the hospital Scientific Council and Ethics Committee. All volunteers were informed as to the aims and the methods of
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the study and gave their informed written consent.
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Exclusion criteria were routine environmental exposure to tobacco smoke, pregnancy,
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black skin, body mass index greater than 30 kg/m2, history of respiratory or cardiovascular
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disease and anemia.
2.2 Study design
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All measurements were made in a temperature-controlled (21 to 22 °C), light-controlled
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environment, utilizing standard equipment.
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Particulate exposure was measured in real time with Dylos DC1700 monitor (Dylos Corporation, Riverside, California, USA), an air quality monitor, which uses a laser light scattering technique to measure the number of particles in two particle size ranges (>0.5 and >2.5 μm) and provides particle counts expressed per 0.01 cubic foot (0.283 litre) (Semple et al., 2013; Semple and Latif, 2014). Near infrared spectrometer (Hutchinson, InSpectra Model 650, Hutchinson Technology, Hutchinson MN, USA) was used for the assessment of thenar-muscle StO2. Thenar-muscle is most widely tested because the subcutaneous adipose tissue layer thickness is small, permitting tissue penetration of the infrared light transmitted from the NIRS probe and StO2 measurement in 6
Journal Pre-proof the corresponding muscle; also the pneumatic cuff can be easily applied above the elbow (Donati et al., 2016; Jones et al., 2016). NIRS derived parameters were monitored by InSpectra software. StO2 curves were analyzed offline with InSpectra Analysis Program, Version 4.01, Hutchinson Technology. The procedure was as following: each subject was comfortably seated and rested for at least 15 min before measurements. Medical history was taken and blood pressure was measured
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with the auscultatory method, which uses sphygmomanometer and stethoscope; also the
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participants’ height and weight were recorded. Baseline NIRS measurements were obtained for
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all subjects, before exposure in a smoke-free environment. The second set of measurements was
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performed after participants stayed in a room polluted with smoke derived from burning
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cigarettes and exhaled from active smokers (approximately 10-15 cigarettes with nicotine 0.70.8mg), for half an hour. Measurements at each phase were made with application of the
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Inspectra StO2 sensor on the surface of the skin above the thenar muscle. Vascular occlusion was obtained with a pneumatic cuff, placed above the elbow, that was rapidly inflated (to 50 mmHg
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above each individual’s systolic blood pressure) to induce arteriovenous occlusion for 3 min.
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Then the cuff was quickly deflated (Figure 1). Baseline StO2, oxygen consumption rate (StO2 decrease slope), reperfusion rate (StO2 increase slope) and the time needed for StO2 to return to baseline levels, after the reactive hyperemic response were assessed (Figure 2). Specifically, baseline StO2 was calculated as the average of the last 2 min signal prior to cuff inflation. Oxygen consumption rate starting point was set at StO2value ≤2% (0.98 times) the baseline StO2 average. Reperfusion rate starting point, immediately following cuff release, was set at StO2 value ≥5% (1.05 times) the baseline StO2 average. The starting points were determined by the analysis software without any operative 7
Journal Pre-proof intervention. The AUC was calculated as the integrated area above the baseline StO2 value for the time interval between the first baseline recovery and when baseline reoccurs after peak hyperemia.
2.3 Statistical analysis
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Normality of distribution was tested with the Shapiro–Wilk test. Differences between
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baseline and after-passive-smoking values were assessed with paired samples t-test or Wilcoxon signed-rank test (in case of not normal distribution). Statistical significance was set to p<0.05.
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Continuous variables are reported as mean ± standard deviation (SD). Effect size was calculated
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as mean of difference/ SD of difference. Statistical analyses were performed with IBM SPSS
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3. RESULTS
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25.0 software.
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All subjects completed the experimental protocol. The average age of the participants was 34±9 years (range: 21 to 56). There were 7 men and 9 women. BaselineStO2 values before passive smoking (79.6±6.4%) and after passive smoking (79.0±8.0%) did not significantly differ (p=0.53). Also, hemodynamic measurements were not altered significantly after exposure to passive smoking (systolic blood pressure 113.1±9.8 vs. 117.8±15.5, p=0.22, diastolic blood pressure 68.7±8.3 vs. 70.0±10.9, p=0.68, heart rate 72.6±6.6 vs. 75.4±7.9, p=0.17). Oxygen consumption rate decreased significantly after exposure to passive smoking (12.8±4.2 vs. 11.3±2.8%/min, -6.4±29.5%, effect size=0.22, p=0.04). Reperfusion rate also significantly decreased (5.6±1.8 vs. 5.0±1.7 %/sec, -7.9±18.2%, effect size=0.43, p=0.04). There was no 8
Journal Pre-proof significant difference in the time needed for StO2 to return to baseline levels (138.2±26.5 vs. 142.1±34.6 sec, p=0.64) and the AUC (18.9±8.6 vs. 18.4±9.2 StO2 units (%)×min, p= 0.81) before and after exposure to passive smoking (Figure 3). Finally, no significant changes were established in Tissue Hemoglobin Index (THI) prior to and immediately after exposure to passive smoking (THI at baseline 14.73±2.8 vs. 14.7±2.9%, p=0.41; THI decrease rate during vascular occlusion was 0.99±1.4 vs. 0.54±0.8%/min, p=0.10; THI increase rate at reperfusion
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was 0.82±0.67 vs. 0.55±0.35%/sec, p=0.12).
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4. DISCUSSION
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The present study examined skeletal muscle microcirculation in healthy non-smokers,
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before and after passive inhalation of side-stream cigarette smoke. Passive smoking significantly affected thenar-muscle microcirculation as assessed by NIRS. In particular, peripheral tissue
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oxygen consumption rate as well as reperfusion rate significantly decreased.
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To our knowledge, this is the first study to investigate the impact of passive smoking on
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skeletal muscle tissue microcirculation utilizing NIRS. Microcirculatory changes due to passive smoking, identified by imaging methods, are related to e.g. the microcirculatory blood flow or the resulting vessel dilation. However, these methods do not give information on skeletal muscle oxidative metabolism and reperfusion rate. Such information is specifically provided by NIRS. Monitoring StO2 with NIRS combined with vascular occlusion technique allows indirect evaluation of oxygen utilization and mitochondrial function as well as endothelial function in diseased and in healthy subjects (Boushel and Piantadosi, 2000; Gerovasili et al., 2010; Siafaka et al., 2007; Tzanis et al., 2016).NIRS methodology has been previously used by Siafaka et al.
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Journal Pre-proof (2007) to evaluate the acute effect of active smoking on microcirculation; they found that, in healthy volunteers, oxygen consumption rate decreased while smoking a cigarette, similarly to our study results, and continued to decrease even 5 minutes after the end of the smoking period. Moreover, the hyperemic response significantly decreased when the participants had smoked nearly half of the cigarette and returned to almost normal levels 5 minutes after the end of the cigarette.
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Henriksson et al. (2014), addressed the effect of passive smoking on microcirculatory
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flow using vital capillaroscopy, which continuously analyzes the flow velocity in a specific
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capillary. They studied the microcirculatory flow in seventeen healthy subjects before, during
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and after passive inhalation of high concentration cigarette smoke, for up to 10 min at each of
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these phases. The exposure was assessed by carbon monoxide gas detector. The investigators demonstrated an immediate effect (decrement) on capillary blood flow velocity that reached to a
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nadir four minutes after the end of exposure. Although measurement of the blood flow velocity
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in specific capillaries is not synonymous with total tissue perfusion, our results might be thought of as complementary to those of this study, possibly demonstrating the effect of altered blood-
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flow, after second-hand smoke exposure, on cellular oxidative metabolism and tissue reoxygenation. However, the possibility of a primary metabolic injury after smoke exposure, which secondarily affects microcirculatory flow (metabolic theory of microcirculatory regulation), cannot be ruled out (Moore et al., 2015). Although the decline of StO2 during stagnant ischemia reflects the thenar muscle oxidative metabolic activity (Romagnoli et al., 2013), the exact mechanism responsible for this microcirculatory/metabolic disorder after passive smoking exposure, as determined by NIRS, has not been clarified yet. A possible explanation could be the carbon monoxide poisoning. CO is a 10
Journal Pre-proof gaseous byproduct formed by incomplete combustion of cigarettes (Apelberg et al., 2013). Jo et al. (2004) found increased breath CO concentrations 30min after passive exposure to smoke, 1.4–2.7 times higher than the background levels, suggesting that passive smoking is the major contributor to the CO exposure of non-smokers working in or visiting a recreation environment. CO, as it enters the bloodstream through breathing, binds with hemoglobin, forming carboxyhemoglobin (COHb). Increased COHb levels result in decreased oxyhemoglobin reducing oxygen delivery to tissues, and cause a leftward shift in the
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concentration,
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oxyhemoglobin dissociation curve and less efficient oxygen extraction (Raub and Benignus,
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2002; Richardson et al, 2002; McDonough and Moffatt, 1999). Asim et al. (2015), have
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investigated the correlation between blood COHb levels and cerebral oxygen saturation, as
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measured by NIRS (cerebral oximetry), in patients with CO gas intoxication. Hypoxic conditions caused by cigarette smoke, can induce adaptive responses in the
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skeletal muscle, as demonstrated in animal models. Specifically, in rats, Nakatani et al. (2003)
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found that, after exposure to cigarette smoke, fiber size decreased and fiber oxidative enzyme
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activity increased, in compensation for the lower oxygen supply in muscle tissue. Another possible explanation for our findings could be mitochondrial dysfunction. Several reports (Fetterman et al., 2017; Knight-Lozano et al., 2002; van der Toorn et al., 2009; Yang et al., 2007), suggest that mitochondria are highly sensitive to toxic components of cigarette smoke; also passive smoking decreases mitochondrial respiration in cellular lever. However, in our study increased concentrations of toxic chemicals inhaled during passive smoking were not adequately and separately documented. Τhe air quality monitor was used only to ensure that the subjects had been sufficiently exposed to sidestream smoke and the study conditions were representable of the intensity of passive exposure in real life conditions. 11
Journal Pre-proof The second finding of our study was the decrease of reperfusion rate 30 min after passive exposure to tobacco smoke. The reperfusion rate corresponds to microvascular reactivity after release of the hypoxic stimulus. The mechanisms that control blood flow distribution at the level of microcirculation have not been fully elucidated. The involvement of endothelium-related agents cannot be excluded (Blitzer et al., 1996; Justice et al., 2000). It has been found that the NIRS-derived upslope (reperfusion rate) was significantly associated with the % Flow Mediated
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Dilation (FMD) response (McLay et al., 2016, Soares et al., 2019), an index of endothelium
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dependent vasodilation (Corretti et al., 2002). Thus, there seems to be a strong correlation
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between upstream and downstream vascular reactivity. However, it has been argued that
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reperfusion upslope of StO2 (in downstream microvasculature) does not indicate the endothelial function but rather reflects the shear rate, an active stimulus for the observed flow mediated
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vascular dilation in the upstream conduit artery (Tremblay and King, 2016; Soares et al., 2019).
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FMD response has been used in previous studies to assess endothelial dysfunction caused
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by passive smoking. In an in vivo study, 30 min of second-hand smoke exposure resulted in a dose dependent impairment of flow mediated dilation (FMD) (Pinnamaneni et al., 2014). Other
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studies have come also to similar conclusions, i.e. brachial artery FMD was reduced after passive inhalation of cigarette smoke (Adams et al., 2015; Gul et al., 2011). Endothelial damage caused by passive smoking is dose-related and can be partly reversible (Puranik and Celermajer, 2003). The underlying mechanism, responsible for the acute endothelial dysfunction after passive smoking, is not yet established. Studies have documented that the cigarette smoke exposure can increase vasoactive mediator production, impair pulmonary endothelial cell function, increasing vascular permeability, induce endothelial activation and inflammation and increase apoptosis (Lu et al., 2018). Furthermore, short term 12
Journal Pre-proof exposure to passive smoking impaired vascular endothelial function, possibly via oxidative stress, in healthy nonsmokers (Kato et al., 2006). Reactive oxygen species can reduce nitric oxide (NO) bioavailability, interfering with its regulatory role in the vascular structure and function (Grassi et al., 2010). Interestingly, Loffredo et al. (2018), provided evidence that nicotinamide adenine dinucleotide phosphate oxidase-2 (NADPH oxidase-2), which generates superoxide anions in humans, is involved in oxidative stress induced by passive smoking;
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NADPH oxidase-2 and isoprostanes (marker of lipid peroxidation) were higher in children
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exposed to passive smoking, while NO bioavailability and FMD were lower, compared with
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controls. Also, NADPH oxidase-2 inversely correlated with FMD in the same study.
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Overall, exposure to secondhand smoke has immediate adverse effects on the
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cardiovascular system, nearly as large as active smoking (Barnoya and Glantz, 2005). This study confirms a rapid and considerable effect of secondhand smoke on microvasculature and tissue
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oxidative metabolism, which could explain the increased cardiovascular risk shown in
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epidemiological studies (He et al., 1999).
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A considerable issue that emerged in our study is the increased oxygen consumption rate and reperfusion rate in few participants after exposure to passive smoking (Figure 4). It seems counterintuitive with respect to what has been previously mentioned for the harmful effect of tobacco smoke on microcirculation. However, one could, possibly, assume a dissimilar response pattern of endothelin receptors after the hypoxic stimulus in individuals with apparently varying level of training and muscular exercise, and, consequently, different adaptive effects on the endothelin system. (Niknazar et al., 2008).
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Journal Pre-proof Limitations A limitation is the small sample size; however, it was a pilot study to provide some preliminary data of the effects of passive smoking and be the basis for further studies. Another possible limitation is the 3 min duration of vascular occlusion technique. According to Ianetta et al. (2019) a longer duration of ischemic phase contributes to greatest reliability regarding the reperfusion slope index. In this study, the selected vascular occlusion duration provided useful
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findings without the participants suffering undue discomfort, which, as has been mentioned, may
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limit their tolerance and may lead to an early discontinuation of the test (Jones et al., 2016);
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furthermore, the 3 min duration vascular occlusion test has been reliably reported by previous
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researchers (Gerovasili et al., 2010).
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Finally, in our study we chose to document the environmental pollution from burning tobacco using an air quality monitor that measures the released particles, formed during tobacco
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combustion. A limitation of our study could be the absence of an objective indicator of the
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magnitude of smoke exposure such as cotinine (a nicotine metabolite) levels in participants.
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However, even the use of this biomarker has certain limitations, i.e. although cotinine levels have been largely used to monitor tobacco exposure, several factors, other than nicotine intake, may affect cotinine levels in blood and urine. Also, cotinine is metabolically processed and its measurement does not fully correspond to total nicotine intake. (Chang et al., 2017)
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Journal Pre-proof Conclusions The present study demonstrates that even a brief exposure to passive smoking decreased peripheral tissue oxygen consumption rate and impaired microvascular reactivity in healthy nonsmoking subjects. However, the precise mechanism responsible for these microcirculatory alterations need further investigation as exposure to passive smoking remains an important
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disease hazard and research issue relating public health.
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5. PERSPECTIVES
Passive smoking remains a public health problem worldwide, despite the legislative
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smoking ban in public places that has been introduced by many countries. The present study
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demonstrates a significant change in the responsiveness of microcirculation after an ischemic
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stimulus as well as a metabolic effect on tissues, in healthy non-smokers, after their short exposure to passive smoking. In spite of the small to moderate effect sizes observed, the 30-min
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duration used in this study is rather the minimum expected duration of daily exposure to passive
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smoking while, long term effects on microcirculation have not been studied yet. From this point of view, this study provides a pathophysiological basis for the passive smoking toxicity in the short term, which could explain the increased cardiovascular risk shown in epidemiologic investigations and should be further analyzed by other studies.
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Journal Pre-proof Authorship SN and IV conceived the idea of the study. SN, EK, IV and VL contributed equally to the conception and design of the research protocol. VL and DD contributed to the sample preparation, carried out the measurements and participated to the acquisition and analysis of NIRS data. Statistical analysis and interpretation of the results was done by LK. The supervision of the study was made by LK, IV and SN. VL drafted the manuscript with the contribution of IV.
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All authors have read and approved the final version of the manuscript.
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Funding
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This trial was partially funded by special account for Research Grants of the National and
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None declared.
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Conflict of interest
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Kapodistrian University of Athens (ELKE).
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REFERENCES Adams, T., et al., 2015. Secondhand Smoking Is Associated With Vascular Inflammation. Chest. 148, 112-119. https://doi: 10.1378/chest.14-2045. Apelberg, B. J., et al., 2013. Environmental monitoring of secondhand smoke exposure. Tob Control. 22, 147-55. https://doi: 10.1136/tobaccocontrol-2011-050301.
of
Asim, K., et al., The Use of Cerebral Oximetry in Acute Carbon Monoxide Intoxication: A Preliminary Study. Keio J Med. 64(4), 57-61. https://doi:10.2302/kjm.2014-0010-OA
ro
Bale, G., et al., 2016. From Jobsis to the present day: a review of clinical near-infrared
-p
spectroscopy measurements of cerebral cytochrome-c-oxidase. J Biomed Opt. 21,
re
091307. https://doi: 10.1117/1.JBO.21.9.091307.
lP
Barnoya, J., Glantz, S. A., 2005. Cardiovascular effects of secondhand smoke: nearly as large as smoking.
Circulation.
111,
2684-98.
na
https://doi:10.1161/CIRCULATIONAHA.104.492215.
ur
Blitzer, M. L., et al., 1996. Endothelium-derived nitric oxide mediates hypoxic vasodilation of resistance
vessels
in
humans.
Am
J
Physiol.
271,
H1182-5.
Jo
https://doi:10.1152/ajpheart.1996.271.3.H1182 Boushel, R., Piantadosi, C. A., 2000. Near-infrared spectroscopy for monitoring muscle oxygenation.
Acta
Physiol
Scand.
168,
615-22.
https://doi:
10.1046/j.1365-
201x.2000.00713.x Chang, C. M., et al., 2017. Biomarkers of Tobacco Exposure: Summary of an FDA-Sponsored Public Workshop. Cancer Epidemiol Biomarkers Prev. 26, 291-302. https://doi: 10.1158/1055-9965.EPI-16-0675
17
Journal Pre-proof Corretti, M. C., et al., 2002. Guidelines for the ultrasound assessment of endothelial-dependent flow-mediated vasodilation of the brachial artery: a report of the International Brachial Artery
Reactivity
Task
Force.
J
Am
Coll
Cardiol.
39,
257-65.
https://doi.org/10.1016/S0735-1097(01)01746-6 Dimopoulos, S., et al., 2013. Peripheral muscle microcirculatory alterations in patients with pulmonary arterial hypertension: a pilot study. Respir Care. 58, 2134-41. https://doi:
of
10.4187/respcare.02113.
ro
Donati, A., et al., 2016. Near-infrared spectroscopy for assessing tissue oxygenation and
-p
microvascular reactivity in critically ill patients: a prospective observational study. Crit
re
Care. 20, 311. https://doi: 10.1186/s13054-016-1500-5. Fetterman, J. L., et al., 2017. Mitochondrial toxicity of tobacco smoke and air pollution.
lP
Toxicology. 391, 18-33. https://doi: 10.1016/j.tox.2017.08.002.
na
Gerovasili, V., et al., 2010. Utilizing the vascular occlusion technique with NIRS technology. Int J Ind Ergon. 40, 218-222. https://doi.org/10.1016/j.ergon.2009.02.004
ur
Grassi, D., et al., 2010. Oxidative stress and endothelial dysfunction: say NO to cigarette
Jo
smoking! Curr Pharm Des. 16, 2539-50. https://doi: 10.2174/138161210792062867 Gul, I., et al., 2011. Acute effects of passive smoking on endothelial function. Angiology. 62, 245-7. https://doi: 10.1177/0003319710377077. He, J., et al., 1999. Passive smoking and the risk of coronary heart disease--a meta-analysis of epidemiologic
studies.
N
Engl
J
Med.
340,
920-6.
https://doi:
10.1056/NEJM199903253401204 Henriksson, P., et al., 2014. Immediate effect of passive smoking on microcirculatory flow. Microcirculation. 21, 587-92. https://doi: 10.1111/micc.12137.
18
Journal Pre-proof Iannetta, D., et al, 2019. Reliability of microvascular responsiveness measures derived from nearinfrared spectroscopy across a variety of ischemic periods in young and older individuals. Microvasc Res. 122, 117-124. https://doi: 10.1016/j.mvr.2018.10.001 Jo, W.K., et al., 2004. Evaluation of exposure to carbon monoxide associated with passive smoking.
Environmental
Research.
94,
309-318.
https://doi.org/10.1016/S0013-
9351(03)00135-X
of
Jones, S., et al., 2016. Recent developments in near-infrared spectroscopy (NIRS) for the
ro
assessment of local skeletal muscle microvascular function and capacity to utilise
-p
oxygen. Artery Res. 16, 25-33. https://doi: 10.1016/j.artres.2016.09.001.
re
Justice, J. M., et al., 2000. Endothelial cell regulation of nitric oxide production during hypoxia in coronary microvessels and epicardial arteries. J Cell Physiol. 182, 359-65.
lP
https://doi:10.1002/(SICI)1097-4652(200003)182:3<359::AID-JCP6>3.0.CO;2-3
na
Kato, T., et al., 2006. Short-term passive smoking causes endothelial dysfunction via oxidative stress in nonsmokers. Can J Physiol Pharmacol. 84, 523-9. https://doi:10.1139/y06-030
ur
Knight-Lozano, C. A., et al., 2002. Cigarette Smoke Exposure and Hypercholesterolemia
Jo
Increase Mitochondrial Damage in Cardiovascular Tissues. Circulation. 105, 849-854. https://doi.org/10.1161/hc0702.103977 Lima, A., Bakker, J., 2011. Near-infrared spectroscopy for monitoring peripheral tissue perfusion in
critically
ill
patients.
Rev
Bras
Ter
Intensiva.
23,
341-51.
http://dx.doi.org/10.1590/S0103-507X2011000300013 Loffredo, L., et al., 2018. Role of NADPH oxidase-2 and oxidative stress in children exposed to passive smoking. Thorax. 73, 986-988. http://doi:10.1136/thoraxjnl-2017-211293
19
Journal Pre-proof Lu, Q., et al., 2018. Effects of cigarette smoke on pulmonary endothelial cells. Am J Physiol Lung
Cell
Mol
Physiol.
314,
L743-l756.
https://doi:
10.1016/j.atherosclerosis.2013.05.015 McDonough, P., Moffatt, R. J., 1999. Smoking-induced elevations in blood carboxyhaemoglobin levels.
Effect
on
maximal
oxygen
uptake.
Sports
Med.
27,
275-83.
https://doi:10.2165/00007256-199927050-00001
of
oxygen
saturation.
Exp
Physiol.
101,
34-40.
ro
measures
of
McLay, K. M., et al., 2016. Vascular responsiveness determined by near-infrared spectroscopy
-p
https://doi.org/10.1113/EP085406
re
Moore, J. P., et al., 2015. Microcirculatory dysfunction and resuscitation: why, when, and how. Br J Anaesth. 115, 366-75. https://doi.org/10.1093/bja/aev163
lP
Morris, P.B., et al., 2015. Cardiovascular Effects of Exposure to Cigarette Smoke and Electronic
na
Cigarettes: Clinical Perspectives From the Prevention of Cardiovascular Disease Section Leadership Council and Early Career Councils of the American College of Cardiology. J
ur
Am Coll Cardiol. 66(12), 1378-91. https://doi:10.1016/j.jacc.2015.07.037
Jo
Nakatani, T., et al., 2003. Effects of exposure to cigarette smoke at different dose levels on extensor digitorum longus muscle fibres in Wistar-Kyoto and spontaneously hypertensive rats.
Clin
Exp
Pharmacol
Physiol.
30,
671-7.
https://doi.org/10.1046/j.1440-
1681.2003.03898.x Niknazar S, F. S., et al., 2008. The Effects of Three Months Exercise on Expression of Endothelin-1
in
the
Lung
Tissue.
J
Biol
Sci.
8,
1092-1095.
https://doi:10.3923/jbs.2008.1092.1095
20
Journal Pre-proof Pinnamaneni, K., et al., 2014. Brief exposure to secondhand smoke reversibly impairs endothelial vasodilatory function. Nicotine Tob Res. 16, 584-90. https://doi: 10.1093/ntr/ntt189. Puranik, R., Celermajer, D. S., 2003. Smoking and endothelial function. Prog Cardiovasc Dis. 45, 443-58. https:// doi: 10.1053/pcad.2003. Rahman, M. M., Laher, I., 2007. Structural and functional alteration of blood vessels caused by
ro
92. https:// doi: 10.2174/157016107782023406
of
cigarette smoking: an overview of molecular mechanisms. Curr Vasc Pharmacol. 5, 276-
-p
Raub, J. A., Benignus, V. A., 2002. Carbon monoxide and the nervous system. Neurosci
re
Biobehav Rev. 26, 925-40. https://doi.org/10.1016/S0149-7634(03)00002-2 Raupach, T., et al., 2006. Secondhand smoke as an acute threat for the cardiovascular system: a
lP
change in paradigm. Eur Heart J. 27, 386-92. https:// doi:10.1093/eurheartj/ehi601
na
Richardson, R. S., et al., 2002. Effect of mild carboxy-hemoglobin on exercising skeletal muscle: intravascular and intracellular evidence. Am J Physiol Regul Integr Comp Physiol. 283,
ur
R1131-9. https://doi: 10.1152/ajpregu.00226.2002
Jo
Robles, J. C., Heaps, C. L., 2015. Adaptations of the endothelin system after exercise training in a porcine model of ischemic heart disease. Microcirculation. 22, 68-78. https://doi: 10.1111/micc.12174. Romagnoli S, et al., 2013. Microcirculation in clinical practice. OA Anaesthetics 1, 16. Schick, S., Glantz, S., 2005. Philip Morris toxicological experiments with fresh sidestream smoke: more toxic than mainstream smoke. Tob Control. 14, 396-404. https://doi: 10.1136/tc.2005.011288.
21
Journal Pre-proof Schneider, M. P., et al., 2007. Contrasting actions of endothelin ET(A) and ET(B) receptors in cardiovascular disease. Annu Rev Pharmacol Toxicol. 47, 731-59. https://doi: 10.1146/annurev.pharmtox.47.120505.105134 Semple, S., et al., 2013. An inexpensive particle monitor for smoker behaviour modification in homes. Tob Control. 22, 295-8. https://doi: 10.1136/tobaccocontrol-2011-050401. Semple, S., Latif, N., 2014. How long does secondhand smoke remain in household air: analysis
of
of PM2.5 data from smokers' homes. Nicotine Tob Res. 16, 1365-70. https://doi:
ro
10.1093/ntr/ntu089.
-p
Siafaka, A., et al., 2007. Acute effects of smoking on skeletal muscle microcirculation monitored
re
by near-infrared spectroscopy. Chest. 131, 1479-85. https://doi: 10.1378/chest.06-2017. Soares, R. N., Murias, J. M., 2018. Near-infrared spectroscopy assessment of microvasculature
lP
detects difference in lower limb vascular responsiveness in obese compared to lean
na
individuals. Microvasc Res. 118, 31-35. https://doi: 10.1016/j.mvr.2018.01.008 Soares, R. N., et al., 2019. The association between near-infrared spectroscopy-derived and flow-
ur
mediated dilation assessment of vascular responsiveness in the arm. Microvasc Res. 122,
Jo
41-44. https://doi: 10.1016/j.mvr.2018.11.005. Sureda, X., et al., 2013. Secondhand tobacco smoke exposure in open and semi-open settings: a systematic
review.
Environ
Health
Perspect.
121,
766-73.
https://doi:
10.1289/ehp.1205806. Torres, S., et al., 2018. Biomarkers of Exposure to Secondhand and Thirdhand Tobacco Smoke: Recent Advances and Future Perspectives. Int J Environ Res Public Health. 15. https://doi: 10.1097/HCR.0000000000000145.
22
Journal Pre-proof Tremblay, J. C., King, T. J., 2016. Near-infrared spectroscopy: can it measure endothelial function? Exp Physiol. 101, 1443-1444. https://doi:10.1113/EP085902 Tzanis, G., et al., 2016. Attenuated Microcirculatory Response to Maximal Exercise in Patients With Chronic Heart Failure. J Cardiopulm Rehabil Prev. 36, 33-7. https://doi: 10.1097/HCR.0000000000000145. van der Toorn, M., et al., 2009. Lipid-soluble components in cigarette smoke induce
of
mitochondrial production of reactive oxygen species in lung epithelial cells. Am J
ro
Physiol Lung Cell Mol Physiol. 297, L109-14. https://doi:10.1152/ajplung.90461.2008.
and
atherosclerosis.
Mutat
Res.
621,
61-74.
re
dysfunction
-p
Yang, Z., et al., 2007. The role of tobacco smoke induced mitochondrial damage in vascular
Jo
ur
na
lP
https://doi:10.1016/j.mrfmmm.2007.02.010.
23
Journal Pre-proof
Figures legends
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Figure 1.Graphical representation of study protocol Figure 2. Near Infrared Spectroscopy-derived O2 saturation signal during baseline and vascular
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occlusion technique: Occlusion period: 3min; AUC: area under the curve. Figure 3. Graphs of NIRS measurements: a. baseline tissue oxygen saturation (StO2); b. oxygen
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consumption rate; c. oxygen reperfusion rate; d. microvascular reactivity before (pre) and after
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(post) exposure to passive smoking in 16 non-smokers healthy volunteers.Paired samples test
na
was employed for a,b,d and Wilcoxon signed-rank test for c. Figure 4. Differences (percentage values) of: a. oxygen consumption rate between pre- and post-
ur
intervention measurement; b. reperfusion rate between pre- and post-intervention measurement.
difference.
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Negative values indicate lower slope at follow-up than baseline. Lines indicate mean value of the
24
Journal Pre-proof HIGHLIGHTS Passive smoking adversely affects microcirculation in healthy non-smokers.
Tissue oxygen consumption rate decreases after exposure to sidestream tobacco smoke.
Microvascular reactivity is altered after exposure to sidestream tobacco smoke.
Passive smoking toxicity implicates severe microcirculatory and metabolic alterations.
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Figure 1
Figure 2
Figure 3
Figure 4
V. Linardatou, E. Karatzanos, N. Panagopoulou, D. Delis, C. Kourek, N. Rovina, S. Nanas, I. Vasileiadis PII:
S0026-2862(19)30075-5
DOI:
https://doi.org/10.1016/j.mvr.2019.103932
Reference:
YMVRE 103932
To appear in:
Microvascular Research
Received date:
4 April 2019
Revised date:
31 August 2019
Accepted date:
26 September 2019
Please cite this article as: V. Linardatou, E. Karatzanos, N. Panagopoulou, et al., Passive smoking acutely affects the microcirculation in healthy non-smokers, Microvascular Research(2019), https://doi.org/10.1016/j.mvr.2019.103932
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© 2019 Published by Elsevier.
Journal Pre-proof
Passive smoking acutely affects the microcirculation in healthy non-smokers V. Linardatou1,2, E. Karatzanos1, N. Panagopoulou1, D. Delis1, C. Kourek1, N. Rovina3, S. Nanas1, I. Vasileiadis3 1
Clinical Ergospirometry Exercise and Rehabilitation Laboratory, Evaggelismos Hospital, School of
Medicine, National and Kapodistrian University of Athens, Athens, Greece 2
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Department of Oncology, General Hospital 'G. Gennimatas', Athens, Greece. ICU, 1stDept of Respiratory Medicine, 'Sotiria' Hospital, School of Medicine, National and Kapodistrian
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3
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University of Athens, Athens, Greece
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Corresponding author:
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IoannisVasileiadis, MD
Assistant Professor of Internal Medicine and Critical Care
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Intensive Care Unit, First Department of Respiratory Medicine, National and Kapodistrian University of Athens, Sotiria Hospital, 152 Mesogeion Ave, 115 27, Athens, Greece
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Email: [email protected], [email protected] Tel: +30 6977644866, +30 210 7763725
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Fax: +30 210 7781250
Journal Pre-proof ABSTRACT Objective: Acute effects of passive smoking on microcirculation have not been sufficiently studied. The aim of the present study was to detect microcirculatory alterations in healthy nonsmokers after passive exposure to cigarette smoke, utilizing the Near Infrared Spectroscopy method combined with the vascular occlusion technique. Methods: Sixteen (9 females, age: 34±9 years) non-smoking, healthy volunteers were exposed
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to passive smoking for 30min in a temperature-controlled environment. Smoke concentration
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was monitored with a real-time particle counter. The following microcirculatory parameters were
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estimated: baseline tissue oxygen saturation (StO2); StO2 decrement after vascular occlusion
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(indicating the oxygen consumption rate); StO2incremental response after vascular occlusion release (reperfusion rate); the time period where the StO2 signal returns to the baseline values
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after the hyperemic response.
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Results: Baseline StO2 (79.6±6.4 vs. 79±8%, p=0.53) as well as the time needed for StO2 to
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return to baseline levels (138.2±26.5 vs. 142.1±34.6 sec, p=0.64) did not significantly differ before vs. after passive smoking exposure. Oxygen consumption rate decreased after 30min
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exposure to passive smoking (from 12.8±4.2 to11.3±2.8 %/min, p=0.04); Reperfusion rate also significantly decreased (from 5.6±1.8 to 5±1.7 %/sec, p=0.04). Conclusions: Our results suggest that acute exposure to passive smoking delays peripheral tissue oxygen consumption and adversely affects microcirculatory responsiveness after stagnant ischemia in healthy non-smokers. Key words: microcirculation; near-infrared spectroscopy; passive smoking; vascular reactivity; endothelium dysfunction
2
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Abbreviations Area Under the Curve
CO
Carbon Monoxide
COHb
Carboxyhemoglobin
FMD
Flow Mediated Dilation
NIRS
Near Infrared Spectroscopy Tissue Oxygen Saturation
THI
Tissue hemoglobin index
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StO2
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AUC
3
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1. INTRODUCTION Passive smoking is the exposition, especially of non-smokers, to second-hand smoke, that comes from the combustion of tobacco and the exhalation of active smokers (Henriksson et al., 2014; Sureda et al., 2013). Smoke inhaled by passive smoking contains thousands of toxic chemicals, including particulate matters (Raupach et al., 2006; Sureda et al., 2013). Sidestream smoke can be more toxic than the mainstream smoke and its toxicity has been proved greater
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than the sum of toxicities of its constituents (Schick and Glantz, 2005; Torres et al., 2018).
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Second-hand smoke toxic exposition has been held responsible for hundreds of thousands
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of deaths worldwide (Torres et al., 2018), a significant proportion of which has been attributed to
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cardiovascular disease (Morris et al, 2015).
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Previous studies have demonstrated the harmful effect of passive smoking on the cardiovascular system. The proposed mechanisms, that probably mediate this harmful effect, are
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platelet dysfunction, endothelial dysfunction, increased inflammation and oxidative stress,
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mitochondrial damage and decreased energy metabolism (Barnoya and Glantz, 2005).
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Nevertheless, the impact of passive smoking specifically on microcirculation has not been extensively studied. Few existing studies are mainly concerned with assessing the effect of passive smoking on the velocity of blood flow in specific capillaries (Henriksson et al., 2014), not providing evidence for the entire microvascular effect, and the flow mediated dilation (FMD), a broad index of endothelial dysfunction (Pinnamaneni et al., 2014). There are no data regarding the acute effect of passive smoking on tissue oxygenation, oxygen consumption and the microvascular reactivity, which altogether evaluate the functional interaction between microcirculatory alterations and tissue oxidative metabolism. This information is provided by Near Infrared Spectroscopy (NIRS) with the vascular occlusion technique. 4
Journal Pre-proof NIRS has been proved a reliable research and clinical tool which uses the principles of light spectroscopy to measure the percentage saturation of hemoglobin with oxygen in all tissue vascular compartments (arterial, capillary, venous), i.e. the tissue oxygen saturation (StO2) (Bale et al., 2016; Romagnoli et al., 2013). StO2 values indicate the balance between oxygen supply and demand. StO2 decline during vascular occlusion corresponds to the tissue oxygen consumption rate, reflecting the oxidative metabolism of the underlying skeletal muscles at rest
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(Gerovasili et al., 2010; Lima and Bakker, 2011; Romagnoli et al., 2013). NIRS derived upslope
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at the reperfusion phase (tissue reperfusion/reoxygenation rate) as well as the under the curve
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area (AUC) are indices of microvascular reactivity; they have been used in various patient
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populations and healthy individuals (Donati et al., 2016; Dimopoulos et al., 2013; Soares and Murias, 2018), where, faster StO2 upslope at the reperfusion phase and greater AUC are
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associated with improved microvascular responsiveness. NIRS methodology has already been
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used to assess the acute effect of active smoking on microcirculation (Siafaka et al., 2007).
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The aim of our study was to evaluate the acute effects of passive smoking on NIRS derived microcirculatory indices, in healthy adults not routinely exposed to tobacco smoke. We
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hypothesized that passive smoking would adversely affect microcirculatory parameters, assessed by NIRS, in healthy non-smokers, i.e., decrease the oxygen consumption rate and the reperfusion rate.
5
Journal Pre-proof 2. MATERIALS AND METHODS
2.1 Study population Sixteen nonsmoking, healthy volunteers participated in the present study, which took place at Evaggelismos hospital. The study protocol was approved by the hospital Scientific Council and Ethics Committee. All volunteers were informed as to the aims and the methods of
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the study and gave their informed written consent.
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Exclusion criteria were routine environmental exposure to tobacco smoke, pregnancy,
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black skin, body mass index greater than 30 kg/m2, history of respiratory or cardiovascular
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disease and anemia.
2.2 Study design
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All measurements were made in a temperature-controlled (21 to 22 °C), light-controlled
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environment, utilizing standard equipment.
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Particulate exposure was measured in real time with Dylos DC1700 monitor (Dylos Corporation, Riverside, California, USA), an air quality monitor, which uses a laser light scattering technique to measure the number of particles in two particle size ranges (>0.5 and >2.5 μm) and provides particle counts expressed per 0.01 cubic foot (0.283 litre) (Semple et al., 2013; Semple and Latif, 2014). Near infrared spectrometer (Hutchinson, InSpectra Model 650, Hutchinson Technology, Hutchinson MN, USA) was used for the assessment of thenar-muscle StO2. Thenar-muscle is most widely tested because the subcutaneous adipose tissue layer thickness is small, permitting tissue penetration of the infrared light transmitted from the NIRS probe and StO2 measurement in 6
Journal Pre-proof the corresponding muscle; also the pneumatic cuff can be easily applied above the elbow (Donati et al., 2016; Jones et al., 2016). NIRS derived parameters were monitored by InSpectra software. StO2 curves were analyzed offline with InSpectra Analysis Program, Version 4.01, Hutchinson Technology. The procedure was as following: each subject was comfortably seated and rested for at least 15 min before measurements. Medical history was taken and blood pressure was measured
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with the auscultatory method, which uses sphygmomanometer and stethoscope; also the
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participants’ height and weight were recorded. Baseline NIRS measurements were obtained for
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all subjects, before exposure in a smoke-free environment. The second set of measurements was
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performed after participants stayed in a room polluted with smoke derived from burning
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cigarettes and exhaled from active smokers (approximately 10-15 cigarettes with nicotine 0.70.8mg), for half an hour. Measurements at each phase were made with application of the
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Inspectra StO2 sensor on the surface of the skin above the thenar muscle. Vascular occlusion was obtained with a pneumatic cuff, placed above the elbow, that was rapidly inflated (to 50 mmHg
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above each individual’s systolic blood pressure) to induce arteriovenous occlusion for 3 min.
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Then the cuff was quickly deflated (Figure 1). Baseline StO2, oxygen consumption rate (StO2 decrease slope), reperfusion rate (StO2 increase slope) and the time needed for StO2 to return to baseline levels, after the reactive hyperemic response were assessed (Figure 2). Specifically, baseline StO2 was calculated as the average of the last 2 min signal prior to cuff inflation. Oxygen consumption rate starting point was set at StO2value ≤2% (0.98 times) the baseline StO2 average. Reperfusion rate starting point, immediately following cuff release, was set at StO2 value ≥5% (1.05 times) the baseline StO2 average. The starting points were determined by the analysis software without any operative 7
Journal Pre-proof intervention. The AUC was calculated as the integrated area above the baseline StO2 value for the time interval between the first baseline recovery and when baseline reoccurs after peak hyperemia.
2.3 Statistical analysis
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Normality of distribution was tested with the Shapiro–Wilk test. Differences between
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baseline and after-passive-smoking values were assessed with paired samples t-test or Wilcoxon signed-rank test (in case of not normal distribution). Statistical significance was set to p<0.05.
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Continuous variables are reported as mean ± standard deviation (SD). Effect size was calculated
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as mean of difference/ SD of difference. Statistical analyses were performed with IBM SPSS
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3. RESULTS
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25.0 software.
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All subjects completed the experimental protocol. The average age of the participants was 34±9 years (range: 21 to 56). There were 7 men and 9 women. BaselineStO2 values before passive smoking (79.6±6.4%) and after passive smoking (79.0±8.0%) did not significantly differ (p=0.53). Also, hemodynamic measurements were not altered significantly after exposure to passive smoking (systolic blood pressure 113.1±9.8 vs. 117.8±15.5, p=0.22, diastolic blood pressure 68.7±8.3 vs. 70.0±10.9, p=0.68, heart rate 72.6±6.6 vs. 75.4±7.9, p=0.17). Oxygen consumption rate decreased significantly after exposure to passive smoking (12.8±4.2 vs. 11.3±2.8%/min, -6.4±29.5%, effect size=0.22, p=0.04). Reperfusion rate also significantly decreased (5.6±1.8 vs. 5.0±1.7 %/sec, -7.9±18.2%, effect size=0.43, p=0.04). There was no 8
Journal Pre-proof significant difference in the time needed for StO2 to return to baseline levels (138.2±26.5 vs. 142.1±34.6 sec, p=0.64) and the AUC (18.9±8.6 vs. 18.4±9.2 StO2 units (%)×min, p= 0.81) before and after exposure to passive smoking (Figure 3). Finally, no significant changes were established in Tissue Hemoglobin Index (THI) prior to and immediately after exposure to passive smoking (THI at baseline 14.73±2.8 vs. 14.7±2.9%, p=0.41; THI decrease rate during vascular occlusion was 0.99±1.4 vs. 0.54±0.8%/min, p=0.10; THI increase rate at reperfusion
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was 0.82±0.67 vs. 0.55±0.35%/sec, p=0.12).
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4. DISCUSSION
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The present study examined skeletal muscle microcirculation in healthy non-smokers,
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before and after passive inhalation of side-stream cigarette smoke. Passive smoking significantly affected thenar-muscle microcirculation as assessed by NIRS. In particular, peripheral tissue
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oxygen consumption rate as well as reperfusion rate significantly decreased.
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To our knowledge, this is the first study to investigate the impact of passive smoking on
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skeletal muscle tissue microcirculation utilizing NIRS. Microcirculatory changes due to passive smoking, identified by imaging methods, are related to e.g. the microcirculatory blood flow or the resulting vessel dilation. However, these methods do not give information on skeletal muscle oxidative metabolism and reperfusion rate. Such information is specifically provided by NIRS. Monitoring StO2 with NIRS combined with vascular occlusion technique allows indirect evaluation of oxygen utilization and mitochondrial function as well as endothelial function in diseased and in healthy subjects (Boushel and Piantadosi, 2000; Gerovasili et al., 2010; Siafaka et al., 2007; Tzanis et al., 2016).NIRS methodology has been previously used by Siafaka et al.
9
Journal Pre-proof (2007) to evaluate the acute effect of active smoking on microcirculation; they found that, in healthy volunteers, oxygen consumption rate decreased while smoking a cigarette, similarly to our study results, and continued to decrease even 5 minutes after the end of the smoking period. Moreover, the hyperemic response significantly decreased when the participants had smoked nearly half of the cigarette and returned to almost normal levels 5 minutes after the end of the cigarette.
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Henriksson et al. (2014), addressed the effect of passive smoking on microcirculatory
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flow using vital capillaroscopy, which continuously analyzes the flow velocity in a specific
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capillary. They studied the microcirculatory flow in seventeen healthy subjects before, during
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and after passive inhalation of high concentration cigarette smoke, for up to 10 min at each of
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these phases. The exposure was assessed by carbon monoxide gas detector. The investigators demonstrated an immediate effect (decrement) on capillary blood flow velocity that reached to a
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nadir four minutes after the end of exposure. Although measurement of the blood flow velocity
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in specific capillaries is not synonymous with total tissue perfusion, our results might be thought of as complementary to those of this study, possibly demonstrating the effect of altered blood-
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flow, after second-hand smoke exposure, on cellular oxidative metabolism and tissue reoxygenation. However, the possibility of a primary metabolic injury after smoke exposure, which secondarily affects microcirculatory flow (metabolic theory of microcirculatory regulation), cannot be ruled out (Moore et al., 2015). Although the decline of StO2 during stagnant ischemia reflects the thenar muscle oxidative metabolic activity (Romagnoli et al., 2013), the exact mechanism responsible for this microcirculatory/metabolic disorder after passive smoking exposure, as determined by NIRS, has not been clarified yet. A possible explanation could be the carbon monoxide poisoning. CO is a 10
Journal Pre-proof gaseous byproduct formed by incomplete combustion of cigarettes (Apelberg et al., 2013). Jo et al. (2004) found increased breath CO concentrations 30min after passive exposure to smoke, 1.4–2.7 times higher than the background levels, suggesting that passive smoking is the major contributor to the CO exposure of non-smokers working in or visiting a recreation environment. CO, as it enters the bloodstream through breathing, binds with hemoglobin, forming carboxyhemoglobin (COHb). Increased COHb levels result in decreased oxyhemoglobin reducing oxygen delivery to tissues, and cause a leftward shift in the
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concentration,
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oxyhemoglobin dissociation curve and less efficient oxygen extraction (Raub and Benignus,
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2002; Richardson et al, 2002; McDonough and Moffatt, 1999). Asim et al. (2015), have
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investigated the correlation between blood COHb levels and cerebral oxygen saturation, as
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measured by NIRS (cerebral oximetry), in patients with CO gas intoxication. Hypoxic conditions caused by cigarette smoke, can induce adaptive responses in the
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skeletal muscle, as demonstrated in animal models. Specifically, in rats, Nakatani et al. (2003)
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found that, after exposure to cigarette smoke, fiber size decreased and fiber oxidative enzyme
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activity increased, in compensation for the lower oxygen supply in muscle tissue. Another possible explanation for our findings could be mitochondrial dysfunction. Several reports (Fetterman et al., 2017; Knight-Lozano et al., 2002; van der Toorn et al., 2009; Yang et al., 2007), suggest that mitochondria are highly sensitive to toxic components of cigarette smoke; also passive smoking decreases mitochondrial respiration in cellular lever. However, in our study increased concentrations of toxic chemicals inhaled during passive smoking were not adequately and separately documented. Τhe air quality monitor was used only to ensure that the subjects had been sufficiently exposed to sidestream smoke and the study conditions were representable of the intensity of passive exposure in real life conditions. 11
Journal Pre-proof The second finding of our study was the decrease of reperfusion rate 30 min after passive exposure to tobacco smoke. The reperfusion rate corresponds to microvascular reactivity after release of the hypoxic stimulus. The mechanisms that control blood flow distribution at the level of microcirculation have not been fully elucidated. The involvement of endothelium-related agents cannot be excluded (Blitzer et al., 1996; Justice et al., 2000). It has been found that the NIRS-derived upslope (reperfusion rate) was significantly associated with the % Flow Mediated
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Dilation (FMD) response (McLay et al., 2016, Soares et al., 2019), an index of endothelium
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dependent vasodilation (Corretti et al., 2002). Thus, there seems to be a strong correlation
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between upstream and downstream vascular reactivity. However, it has been argued that
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reperfusion upslope of StO2 (in downstream microvasculature) does not indicate the endothelial function but rather reflects the shear rate, an active stimulus for the observed flow mediated
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vascular dilation in the upstream conduit artery (Tremblay and King, 2016; Soares et al., 2019).
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FMD response has been used in previous studies to assess endothelial dysfunction caused
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by passive smoking. In an in vivo study, 30 min of second-hand smoke exposure resulted in a dose dependent impairment of flow mediated dilation (FMD) (Pinnamaneni et al., 2014). Other
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studies have come also to similar conclusions, i.e. brachial artery FMD was reduced after passive inhalation of cigarette smoke (Adams et al., 2015; Gul et al., 2011). Endothelial damage caused by passive smoking is dose-related and can be partly reversible (Puranik and Celermajer, 2003). The underlying mechanism, responsible for the acute endothelial dysfunction after passive smoking, is not yet established. Studies have documented that the cigarette smoke exposure can increase vasoactive mediator production, impair pulmonary endothelial cell function, increasing vascular permeability, induce endothelial activation and inflammation and increase apoptosis (Lu et al., 2018). Furthermore, short term 12
Journal Pre-proof exposure to passive smoking impaired vascular endothelial function, possibly via oxidative stress, in healthy nonsmokers (Kato et al., 2006). Reactive oxygen species can reduce nitric oxide (NO) bioavailability, interfering with its regulatory role in the vascular structure and function (Grassi et al., 2010). Interestingly, Loffredo et al. (2018), provided evidence that nicotinamide adenine dinucleotide phosphate oxidase-2 (NADPH oxidase-2), which generates superoxide anions in humans, is involved in oxidative stress induced by passive smoking;
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NADPH oxidase-2 and isoprostanes (marker of lipid peroxidation) were higher in children
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exposed to passive smoking, while NO bioavailability and FMD were lower, compared with
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controls. Also, NADPH oxidase-2 inversely correlated with FMD in the same study.
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Overall, exposure to secondhand smoke has immediate adverse effects on the
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cardiovascular system, nearly as large as active smoking (Barnoya and Glantz, 2005). This study confirms a rapid and considerable effect of secondhand smoke on microvasculature and tissue
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oxidative metabolism, which could explain the increased cardiovascular risk shown in
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epidemiological studies (He et al., 1999).
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A considerable issue that emerged in our study is the increased oxygen consumption rate and reperfusion rate in few participants after exposure to passive smoking (Figure 4). It seems counterintuitive with respect to what has been previously mentioned for the harmful effect of tobacco smoke on microcirculation. However, one could, possibly, assume a dissimilar response pattern of endothelin receptors after the hypoxic stimulus in individuals with apparently varying level of training and muscular exercise, and, consequently, different adaptive effects on the endothelin system. (Niknazar et al., 2008).
13
Journal Pre-proof Limitations A limitation is the small sample size; however, it was a pilot study to provide some preliminary data of the effects of passive smoking and be the basis for further studies. Another possible limitation is the 3 min duration of vascular occlusion technique. According to Ianetta et al. (2019) a longer duration of ischemic phase contributes to greatest reliability regarding the reperfusion slope index. In this study, the selected vascular occlusion duration provided useful
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findings without the participants suffering undue discomfort, which, as has been mentioned, may
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limit their tolerance and may lead to an early discontinuation of the test (Jones et al., 2016);
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furthermore, the 3 min duration vascular occlusion test has been reliably reported by previous
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researchers (Gerovasili et al., 2010).
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Finally, in our study we chose to document the environmental pollution from burning tobacco using an air quality monitor that measures the released particles, formed during tobacco
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combustion. A limitation of our study could be the absence of an objective indicator of the
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magnitude of smoke exposure such as cotinine (a nicotine metabolite) levels in participants.
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However, even the use of this biomarker has certain limitations, i.e. although cotinine levels have been largely used to monitor tobacco exposure, several factors, other than nicotine intake, may affect cotinine levels in blood and urine. Also, cotinine is metabolically processed and its measurement does not fully correspond to total nicotine intake. (Chang et al., 2017)
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Journal Pre-proof Conclusions The present study demonstrates that even a brief exposure to passive smoking decreased peripheral tissue oxygen consumption rate and impaired microvascular reactivity in healthy nonsmoking subjects. However, the precise mechanism responsible for these microcirculatory alterations need further investigation as exposure to passive smoking remains an important
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disease hazard and research issue relating public health.
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5. PERSPECTIVES
Passive smoking remains a public health problem worldwide, despite the legislative
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smoking ban in public places that has been introduced by many countries. The present study
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demonstrates a significant change in the responsiveness of microcirculation after an ischemic
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stimulus as well as a metabolic effect on tissues, in healthy non-smokers, after their short exposure to passive smoking. In spite of the small to moderate effect sizes observed, the 30-min
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duration used in this study is rather the minimum expected duration of daily exposure to passive
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smoking while, long term effects on microcirculation have not been studied yet. From this point of view, this study provides a pathophysiological basis for the passive smoking toxicity in the short term, which could explain the increased cardiovascular risk shown in epidemiologic investigations and should be further analyzed by other studies.
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Journal Pre-proof Authorship SN and IV conceived the idea of the study. SN, EK, IV and VL contributed equally to the conception and design of the research protocol. VL and DD contributed to the sample preparation, carried out the measurements and participated to the acquisition and analysis of NIRS data. Statistical analysis and interpretation of the results was done by LK. The supervision of the study was made by LK, IV and SN. VL drafted the manuscript with the contribution of IV.
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All authors have read and approved the final version of the manuscript.
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Funding
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This trial was partially funded by special account for Research Grants of the National and
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None declared.
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Conflict of interest
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Kapodistrian University of Athens (ELKE).
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REFERENCES Adams, T., et al., 2015. Secondhand Smoking Is Associated With Vascular Inflammation. Chest. 148, 112-119. https://doi: 10.1378/chest.14-2045. Apelberg, B. J., et al., 2013. Environmental monitoring of secondhand smoke exposure. Tob Control. 22, 147-55. https://doi: 10.1136/tobaccocontrol-2011-050301.
of
Asim, K., et al., The Use of Cerebral Oximetry in Acute Carbon Monoxide Intoxication: A Preliminary Study. Keio J Med. 64(4), 57-61. https://doi:10.2302/kjm.2014-0010-OA
ro
Bale, G., et al., 2016. From Jobsis to the present day: a review of clinical near-infrared
-p
spectroscopy measurements of cerebral cytochrome-c-oxidase. J Biomed Opt. 21,
re
091307. https://doi: 10.1117/1.JBO.21.9.091307.
lP
Barnoya, J., Glantz, S. A., 2005. Cardiovascular effects of secondhand smoke: nearly as large as smoking.
Circulation.
111,
2684-98.
na
https://doi:10.1161/CIRCULATIONAHA.104.492215.
ur
Blitzer, M. L., et al., 1996. Endothelium-derived nitric oxide mediates hypoxic vasodilation of resistance
vessels
in
humans.
Am
J
Physiol.
271,
H1182-5.
Jo
https://doi:10.1152/ajpheart.1996.271.3.H1182 Boushel, R., Piantadosi, C. A., 2000. Near-infrared spectroscopy for monitoring muscle oxygenation.
Acta
Physiol
Scand.
168,
615-22.
https://doi:
10.1046/j.1365-
201x.2000.00713.x Chang, C. M., et al., 2017. Biomarkers of Tobacco Exposure: Summary of an FDA-Sponsored Public Workshop. Cancer Epidemiol Biomarkers Prev. 26, 291-302. https://doi: 10.1158/1055-9965.EPI-16-0675
17
Journal Pre-proof Corretti, M. C., et al., 2002. Guidelines for the ultrasound assessment of endothelial-dependent flow-mediated vasodilation of the brachial artery: a report of the International Brachial Artery
Reactivity
Task
Force.
J
Am
Coll
Cardiol.
39,
257-65.
https://doi.org/10.1016/S0735-1097(01)01746-6 Dimopoulos, S., et al., 2013. Peripheral muscle microcirculatory alterations in patients with pulmonary arterial hypertension: a pilot study. Respir Care. 58, 2134-41. https://doi:
of
10.4187/respcare.02113.
ro
Donati, A., et al., 2016. Near-infrared spectroscopy for assessing tissue oxygenation and
-p
microvascular reactivity in critically ill patients: a prospective observational study. Crit
re
Care. 20, 311. https://doi: 10.1186/s13054-016-1500-5. Fetterman, J. L., et al., 2017. Mitochondrial toxicity of tobacco smoke and air pollution.
lP
Toxicology. 391, 18-33. https://doi: 10.1016/j.tox.2017.08.002.
na
Gerovasili, V., et al., 2010. Utilizing the vascular occlusion technique with NIRS technology. Int J Ind Ergon. 40, 218-222. https://doi.org/10.1016/j.ergon.2009.02.004
ur
Grassi, D., et al., 2010. Oxidative stress and endothelial dysfunction: say NO to cigarette
Jo
smoking! Curr Pharm Des. 16, 2539-50. https://doi: 10.2174/138161210792062867 Gul, I., et al., 2011. Acute effects of passive smoking on endothelial function. Angiology. 62, 245-7. https://doi: 10.1177/0003319710377077. He, J., et al., 1999. Passive smoking and the risk of coronary heart disease--a meta-analysis of epidemiologic
studies.
N
Engl
J
Med.
340,
920-6.
https://doi:
10.1056/NEJM199903253401204 Henriksson, P., et al., 2014. Immediate effect of passive smoking on microcirculatory flow. Microcirculation. 21, 587-92. https://doi: 10.1111/micc.12137.
18
Journal Pre-proof Iannetta, D., et al, 2019. Reliability of microvascular responsiveness measures derived from nearinfrared spectroscopy across a variety of ischemic periods in young and older individuals. Microvasc Res. 122, 117-124. https://doi: 10.1016/j.mvr.2018.10.001 Jo, W.K., et al., 2004. Evaluation of exposure to carbon monoxide associated with passive smoking.
Environmental
Research.
94,
309-318.
https://doi.org/10.1016/S0013-
9351(03)00135-X
of
Jones, S., et al., 2016. Recent developments in near-infrared spectroscopy (NIRS) for the
ro
assessment of local skeletal muscle microvascular function and capacity to utilise
-p
oxygen. Artery Res. 16, 25-33. https://doi: 10.1016/j.artres.2016.09.001.
re
Justice, J. M., et al., 2000. Endothelial cell regulation of nitric oxide production during hypoxia in coronary microvessels and epicardial arteries. J Cell Physiol. 182, 359-65.
lP
https://doi:10.1002/(SICI)1097-4652(200003)182:3<359::AID-JCP6>3.0.CO;2-3
na
Kato, T., et al., 2006. Short-term passive smoking causes endothelial dysfunction via oxidative stress in nonsmokers. Can J Physiol Pharmacol. 84, 523-9. https://doi:10.1139/y06-030
ur
Knight-Lozano, C. A., et al., 2002. Cigarette Smoke Exposure and Hypercholesterolemia
Jo
Increase Mitochondrial Damage in Cardiovascular Tissues. Circulation. 105, 849-854. https://doi.org/10.1161/hc0702.103977 Lima, A., Bakker, J., 2011. Near-infrared spectroscopy for monitoring peripheral tissue perfusion in
critically
ill
patients.
Rev
Bras
Ter
Intensiva.
23,
341-51.
http://dx.doi.org/10.1590/S0103-507X2011000300013 Loffredo, L., et al., 2018. Role of NADPH oxidase-2 and oxidative stress in children exposed to passive smoking. Thorax. 73, 986-988. http://doi:10.1136/thoraxjnl-2017-211293
19
Journal Pre-proof Lu, Q., et al., 2018. Effects of cigarette smoke on pulmonary endothelial cells. Am J Physiol Lung
Cell
Mol
Physiol.
314,
L743-l756.
https://doi:
10.1016/j.atherosclerosis.2013.05.015 McDonough, P., Moffatt, R. J., 1999. Smoking-induced elevations in blood carboxyhaemoglobin levels.
Effect
on
maximal
oxygen
uptake.
Sports
Med.
27,
275-83.
https://doi:10.2165/00007256-199927050-00001
of
oxygen
saturation.
Exp
Physiol.
101,
34-40.
ro
measures
of
McLay, K. M., et al., 2016. Vascular responsiveness determined by near-infrared spectroscopy
-p
https://doi.org/10.1113/EP085406
re
Moore, J. P., et al., 2015. Microcirculatory dysfunction and resuscitation: why, when, and how. Br J Anaesth. 115, 366-75. https://doi.org/10.1093/bja/aev163
lP
Morris, P.B., et al., 2015. Cardiovascular Effects of Exposure to Cigarette Smoke and Electronic
na
Cigarettes: Clinical Perspectives From the Prevention of Cardiovascular Disease Section Leadership Council and Early Career Councils of the American College of Cardiology. J
ur
Am Coll Cardiol. 66(12), 1378-91. https://doi:10.1016/j.jacc.2015.07.037
Jo
Nakatani, T., et al., 2003. Effects of exposure to cigarette smoke at different dose levels on extensor digitorum longus muscle fibres in Wistar-Kyoto and spontaneously hypertensive rats.
Clin
Exp
Pharmacol
Physiol.
30,
671-7.
https://doi.org/10.1046/j.1440-
1681.2003.03898.x Niknazar S, F. S., et al., 2008. The Effects of Three Months Exercise on Expression of Endothelin-1
in
the
Lung
Tissue.
J
Biol
Sci.
8,
1092-1095.
https://doi:10.3923/jbs.2008.1092.1095
20
Journal Pre-proof Pinnamaneni, K., et al., 2014. Brief exposure to secondhand smoke reversibly impairs endothelial vasodilatory function. Nicotine Tob Res. 16, 584-90. https://doi: 10.1093/ntr/ntt189. Puranik, R., Celermajer, D. S., 2003. Smoking and endothelial function. Prog Cardiovasc Dis. 45, 443-58. https:// doi: 10.1053/pcad.2003. Rahman, M. M., Laher, I., 2007. Structural and functional alteration of blood vessels caused by
ro
92. https:// doi: 10.2174/157016107782023406
of
cigarette smoking: an overview of molecular mechanisms. Curr Vasc Pharmacol. 5, 276-
-p
Raub, J. A., Benignus, V. A., 2002. Carbon monoxide and the nervous system. Neurosci
re
Biobehav Rev. 26, 925-40. https://doi.org/10.1016/S0149-7634(03)00002-2 Raupach, T., et al., 2006. Secondhand smoke as an acute threat for the cardiovascular system: a
lP
change in paradigm. Eur Heart J. 27, 386-92. https:// doi:10.1093/eurheartj/ehi601
na
Richardson, R. S., et al., 2002. Effect of mild carboxy-hemoglobin on exercising skeletal muscle: intravascular and intracellular evidence. Am J Physiol Regul Integr Comp Physiol. 283,
ur
R1131-9. https://doi: 10.1152/ajpregu.00226.2002
Jo
Robles, J. C., Heaps, C. L., 2015. Adaptations of the endothelin system after exercise training in a porcine model of ischemic heart disease. Microcirculation. 22, 68-78. https://doi: 10.1111/micc.12174. Romagnoli S, et al., 2013. Microcirculation in clinical practice. OA Anaesthetics 1, 16. Schick, S., Glantz, S., 2005. Philip Morris toxicological experiments with fresh sidestream smoke: more toxic than mainstream smoke. Tob Control. 14, 396-404. https://doi: 10.1136/tc.2005.011288.
21
Journal Pre-proof Schneider, M. P., et al., 2007. Contrasting actions of endothelin ET(A) and ET(B) receptors in cardiovascular disease. Annu Rev Pharmacol Toxicol. 47, 731-59. https://doi: 10.1146/annurev.pharmtox.47.120505.105134 Semple, S., et al., 2013. An inexpensive particle monitor for smoker behaviour modification in homes. Tob Control. 22, 295-8. https://doi: 10.1136/tobaccocontrol-2011-050401. Semple, S., Latif, N., 2014. How long does secondhand smoke remain in household air: analysis
of
of PM2.5 data from smokers' homes. Nicotine Tob Res. 16, 1365-70. https://doi:
ro
10.1093/ntr/ntu089.
-p
Siafaka, A., et al., 2007. Acute effects of smoking on skeletal muscle microcirculation monitored
re
by near-infrared spectroscopy. Chest. 131, 1479-85. https://doi: 10.1378/chest.06-2017. Soares, R. N., Murias, J. M., 2018. Near-infrared spectroscopy assessment of microvasculature
lP
detects difference in lower limb vascular responsiveness in obese compared to lean
na
individuals. Microvasc Res. 118, 31-35. https://doi: 10.1016/j.mvr.2018.01.008 Soares, R. N., et al., 2019. The association between near-infrared spectroscopy-derived and flow-
ur
mediated dilation assessment of vascular responsiveness in the arm. Microvasc Res. 122,
Jo
41-44. https://doi: 10.1016/j.mvr.2018.11.005. Sureda, X., et al., 2013. Secondhand tobacco smoke exposure in open and semi-open settings: a systematic
review.
Environ
Health
Perspect.
121,
766-73.
https://doi:
10.1289/ehp.1205806. Torres, S., et al., 2018. Biomarkers of Exposure to Secondhand and Thirdhand Tobacco Smoke: Recent Advances and Future Perspectives. Int J Environ Res Public Health. 15. https://doi: 10.1097/HCR.0000000000000145.
22
Journal Pre-proof Tremblay, J. C., King, T. J., 2016. Near-infrared spectroscopy: can it measure endothelial function? Exp Physiol. 101, 1443-1444. https://doi:10.1113/EP085902 Tzanis, G., et al., 2016. Attenuated Microcirculatory Response to Maximal Exercise in Patients With Chronic Heart Failure. J Cardiopulm Rehabil Prev. 36, 33-7. https://doi: 10.1097/HCR.0000000000000145. van der Toorn, M., et al., 2009. Lipid-soluble components in cigarette smoke induce
of
mitochondrial production of reactive oxygen species in lung epithelial cells. Am J
ro
Physiol Lung Cell Mol Physiol. 297, L109-14. https://doi:10.1152/ajplung.90461.2008.
and
atherosclerosis.
Mutat
Res.
621,
61-74.
re
dysfunction
-p
Yang, Z., et al., 2007. The role of tobacco smoke induced mitochondrial damage in vascular
Jo
ur
na
lP
https://doi:10.1016/j.mrfmmm.2007.02.010.
23
Journal Pre-proof
Figures legends
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Figure 1.Graphical representation of study protocol Figure 2. Near Infrared Spectroscopy-derived O2 saturation signal during baseline and vascular
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occlusion technique: Occlusion period: 3min; AUC: area under the curve. Figure 3. Graphs of NIRS measurements: a. baseline tissue oxygen saturation (StO2); b. oxygen
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consumption rate; c. oxygen reperfusion rate; d. microvascular reactivity before (pre) and after
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(post) exposure to passive smoking in 16 non-smokers healthy volunteers.Paired samples test
na
was employed for a,b,d and Wilcoxon signed-rank test for c. Figure 4. Differences (percentage values) of: a. oxygen consumption rate between pre- and post-
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intervention measurement; b. reperfusion rate between pre- and post-intervention measurement.
difference.
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Negative values indicate lower slope at follow-up than baseline. Lines indicate mean value of the
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Journal Pre-proof HIGHLIGHTS Passive smoking adversely affects microcirculation in healthy non-smokers.
Tissue oxygen consumption rate decreases after exposure to sidestream tobacco smoke.
Microvascular reactivity is altered after exposure to sidestream tobacco smoke.
Passive smoking toxicity implicates severe microcirculatory and metabolic alterations.
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Figure 1
Figure 2
Figure 3
Figure 4