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Evaluation of tissue factor bearing microparticles in the cord blood of preterm and term newborns
Thrombosis Research 153 (2017) 95–96
Contents lists available at ScienceDirect
Thrombosis Research journal homepage: www.elsevier.com/locate/thromres
Letter to the Editors-in-Chief Evaluation of tissue factor bearing microparticles in the cord blood of preterm and term newborns
Dear Editor, Tissue factor (TF) plays a fundamental role in the blood coagulation by binding and activating coagulation factor VII [1]. In fact, recent data suggest that the main source of TF is tissue factor bearing microparticles (MPs-TF) [2]. So far, the associations between the levels of TF, MPs-TF and gestational age have not been exhaustively examined. Therefore, the roles of these coagulation biomarkers in the cord blood of newborns should be clarified. In this pilot paper we sought to investigate the levels of TF and MPs-TF in the cord blood of preterm and term neonates. The study was performed on the cord blood of 48 newborns (23 preterm and 25 term). According to World Health Organization, preterm birth was defined as birth before the 37th completed weeks of gestation. From the clinical records we obtained information on gestational age, gender of the infants, birth weight, Apgar score in the 1st, 3rd and the 5th minute, maternal age, gravidity, parity, and the mode of delivery. Infants born at b25 completed weeks gestation or with major birth defects were excluded. For the analysis, we also excluded over-term infants (N42 weeks of gestational age) and the newborns or the mothers with missing or incomplete prenatal care records. After delivery, blood samples from the umbilical vein were obtained before placenta expulsion and after clamping of the umbilical cord and collected into tubes containing 3.2% sodium citrate. The samples for MPs-TF determination were centrifuged twice. First, blood was centrifuged at 1500g for 15 min in room temperature. Then, plasma supernatant was pipette into Eppendorf tubes and was rapidly centrifuged at 13,000g for 2 min in room temperature. Blood for TF determination was centrifuged at 1500g for 20 min (4 °C). The samples were then collected and stored at −80 °C until examination. Total TF and MPs-TF levels were measured using enzyme-linked immunosorbent assays (Hyphen Biomed, France). The details about kits can be found in reference [3]. The data are expressed as a median (Me) and interquartile range (IQR). The two newborn groups were compared using the Mann–Whitney U test. Correlation coefficients were determined by Spearman's test. A probability b0.05 was considered statistically significant (p b 0.05). Table 1 presents the characteristics of the study infants and their mothers. Preterm infants had higher MPs-TF levels than term infants (Me, 10.61 pg/mL versus 5.67 pg/mL), the difference was however only marginally significant (p = 0.05). In infants born prematurely, cord blood plasma total TF levels did not differ significantly from that in term newborns (Me, 51.13 pg/mL versus 49.31 pg/mL, p = 0.47). These results are summarized in Fig. 1. When two groups of newborns were combined together (n = 48), MPs-TF levels showed significant correlations with gestational age and newborn's weight (R = − 0.3, p = 0.02; R = − 0.4; p = 0.003, respectively). In contrast, no
http://dx.doi.org/10.1016/j.thromres.2017.02.017 0049-3848/© 2017 Elsevier Ltd. All rights reserved.
significant correlations were observed between total TF levels, gestational age and newborn's weight. Microparticles (MPs) are the fragments of cell membranes released in response to inflammation, apoptosis or cells activation [4]. The role of MPs in various pathological conditions [5] has been extensively studied, however their levels during fetal life remains undetermined. In our pilot study we found presence of MPs-TF in all samples of the cord blood, however higher levels of these MPs were observed in the group of premature infants. Based on our findings we can suggest that MPsTF are constant component of the cord blood. Remarkably, it has been reported that preterm infants are at high risk of thromboembolic events due to the effects of various acquired perinatal and iatrogenic conditions [6–8]. In our opinion, higher cord blood MPs-TF levels could explain partially this phenomenon. Additionally, we hypothesize that increased levels of MPs-TF may compensate the ‘immaturity’ of the newborn coagulation system. Nevertheless, our results should be interpreted with caution as the limited number of newborns was included. Doubtlessly, future studies should shed more light on the relationship between MPs-TF levels and prenatal development.
References [1] H.H. Versteeg, Tissue factor: old and new links with cancer biology, Semin. Thromb. Hemost. 41 (7) (2015) 747–755, http://dx.doi.org/10.1055/s-0035-1556048. [2] N. van Es, S. Bleker, A. Sturk, R. Nieuwland, Clinical significance of tissue factor-exposing microparticles in arterial and venous thrombosis, Semin. Thromb. Hemost. 41 (7) (2015) 718–727, http://dx.doi.org/10.1055/s-0035-1556047.
Table 1 Demographic and clinical characteristics of newborns. Parametera [unit]
Preterm infants (n = 23)
Term infants (n = 25)
Sex of infant (F/M) Gestational age [weeks] Birth weight [g] APGAR score 1st min 3rd min 5th min Maternal age [years] Gravidity Parity Model of delivery (V/C)
12/11 34 (32–36) 2130 (1640–2500) 8 (6–9) 9 (7–9) 9 (8–10) 29.5 (25–32) 2 (1–2) 1 (1–2) 7/16
10/15 40 (39–41)† 3480 (3280–3810)† 10 (9–10)† 10 (9–10)† 10 (10−10)† 28.5 (27–33) 2 (1–2) 1 (1–2) 16/9
Abbreviations: F: female, M: male, min: minute, V: vaginal delivery, C: cesarean section. a Values are median (Me) and (IQR) or number of newborns or mothers. † p b 0.05 in comparison to preterm infants (Mann–Whitney U test).
96
Letter to the Editors-in-Chief [5] S. Nomura, M. Shimizu, Clinical significance of procoagulant microparticles, J. Intensive Care 3 (1) (2015) 2, http://dx.doi.org/10.1186/s40560-014-0066-z. [6] C. Thornburg, S. Pipe, Neonatal thromboembolic emergencies, Semin. Fetal Neonatal Med. 11 (3) (2006) 198–206, http://dx.doi.org/10.1016/j.siny.2006.01.005. [7] P. Saracco, E. Parodi, C. Fabris, V. Cecinati, A.C. Molinari, P. Giordano, Management and investigation of neonatal thromboembolic events: genetic and acquired risk factors, Thromb. Res. 123 (6) (2009) 805–809, http://dx.doi.org/10.1016/j.thromres.2008. 12.002. [8] R. Bhat, P. Monagle, The preterm infant with thrombosis, Arch. Dis. Child. Fetal Neonatal Ed. 97 (6) (2012) 423–428, http://dx.doi.org/10.1136/archdischild-2011301142.
Piotr Korbal Department of Propedeutics of Medicine, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Poland Department of Neonatology and Neonatal Intensive Care, Jan Biziel University Hospital No 2, Bydgoszcz, Poland Corresponding author at: Department of Propedeutics of Medicine, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum in Bydgoszcz, 9 Skłodowskiej–Curie Str., 85-094 Bydgoszcz, Poland. E-mail address: [email protected]. Artur Słomka Department of Pathophysiology, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Poland Iwona Sadowska-Krawczenko Department of Neonatology and Neonatal Intensive Care, Jan Biziel University Hospital No 2, Bydgoszcz, Poland Ewa Żekanowska Department of Pathophysiology, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Poland Fig. 1. The levels of MPs-TF (1A) and total TF (1B) in the cord blood of preterm infants (n = 23) and term infants (n = 25).
[3] A. Słomka, M. Świtońska, W. Sinkiewicz, E. Żekanowska, Haemostatic factors do not account for worse outcomes from ischaemic stroke in patients with higher C-reactive protein concentrations, Ann. Clin. Biochem. (2016) http://dx.doi.org/10.1177/ 0004563216663775. [4] L. Badimon, R. Suades, E. Fuentes, I. Palomo, T. Padró, Role of platelet-derived microvesicles as crosstalk mediators in atherothrombosis and future pharmacology targets: a link between inflammation, atherosclerosis, and thrombosis, Front. Pharmacol. 7 (2016) 293, http://dx.doi.org/10.3389/fphar.2016.00293.
23 December 2016 Available online 1 March 2017
Contents lists available at ScienceDirect
Thrombosis Research journal homepage: www.elsevier.com/locate/thromres
Letter to the Editors-in-Chief Evaluation of tissue factor bearing microparticles in the cord blood of preterm and term newborns
Dear Editor, Tissue factor (TF) plays a fundamental role in the blood coagulation by binding and activating coagulation factor VII [1]. In fact, recent data suggest that the main source of TF is tissue factor bearing microparticles (MPs-TF) [2]. So far, the associations between the levels of TF, MPs-TF and gestational age have not been exhaustively examined. Therefore, the roles of these coagulation biomarkers in the cord blood of newborns should be clarified. In this pilot paper we sought to investigate the levels of TF and MPs-TF in the cord blood of preterm and term neonates. The study was performed on the cord blood of 48 newborns (23 preterm and 25 term). According to World Health Organization, preterm birth was defined as birth before the 37th completed weeks of gestation. From the clinical records we obtained information on gestational age, gender of the infants, birth weight, Apgar score in the 1st, 3rd and the 5th minute, maternal age, gravidity, parity, and the mode of delivery. Infants born at b25 completed weeks gestation or with major birth defects were excluded. For the analysis, we also excluded over-term infants (N42 weeks of gestational age) and the newborns or the mothers with missing or incomplete prenatal care records. After delivery, blood samples from the umbilical vein were obtained before placenta expulsion and after clamping of the umbilical cord and collected into tubes containing 3.2% sodium citrate. The samples for MPs-TF determination were centrifuged twice. First, blood was centrifuged at 1500g for 15 min in room temperature. Then, plasma supernatant was pipette into Eppendorf tubes and was rapidly centrifuged at 13,000g for 2 min in room temperature. Blood for TF determination was centrifuged at 1500g for 20 min (4 °C). The samples were then collected and stored at −80 °C until examination. Total TF and MPs-TF levels were measured using enzyme-linked immunosorbent assays (Hyphen Biomed, France). The details about kits can be found in reference [3]. The data are expressed as a median (Me) and interquartile range (IQR). The two newborn groups were compared using the Mann–Whitney U test. Correlation coefficients were determined by Spearman's test. A probability b0.05 was considered statistically significant (p b 0.05). Table 1 presents the characteristics of the study infants and their mothers. Preterm infants had higher MPs-TF levels than term infants (Me, 10.61 pg/mL versus 5.67 pg/mL), the difference was however only marginally significant (p = 0.05). In infants born prematurely, cord blood plasma total TF levels did not differ significantly from that in term newborns (Me, 51.13 pg/mL versus 49.31 pg/mL, p = 0.47). These results are summarized in Fig. 1. When two groups of newborns were combined together (n = 48), MPs-TF levels showed significant correlations with gestational age and newborn's weight (R = − 0.3, p = 0.02; R = − 0.4; p = 0.003, respectively). In contrast, no
http://dx.doi.org/10.1016/j.thromres.2017.02.017 0049-3848/© 2017 Elsevier Ltd. All rights reserved.
significant correlations were observed between total TF levels, gestational age and newborn's weight. Microparticles (MPs) are the fragments of cell membranes released in response to inflammation, apoptosis or cells activation [4]. The role of MPs in various pathological conditions [5] has been extensively studied, however their levels during fetal life remains undetermined. In our pilot study we found presence of MPs-TF in all samples of the cord blood, however higher levels of these MPs were observed in the group of premature infants. Based on our findings we can suggest that MPsTF are constant component of the cord blood. Remarkably, it has been reported that preterm infants are at high risk of thromboembolic events due to the effects of various acquired perinatal and iatrogenic conditions [6–8]. In our opinion, higher cord blood MPs-TF levels could explain partially this phenomenon. Additionally, we hypothesize that increased levels of MPs-TF may compensate the ‘immaturity’ of the newborn coagulation system. Nevertheless, our results should be interpreted with caution as the limited number of newborns was included. Doubtlessly, future studies should shed more light on the relationship between MPs-TF levels and prenatal development.
References [1] H.H. Versteeg, Tissue factor: old and new links with cancer biology, Semin. Thromb. Hemost. 41 (7) (2015) 747–755, http://dx.doi.org/10.1055/s-0035-1556048. [2] N. van Es, S. Bleker, A. Sturk, R. Nieuwland, Clinical significance of tissue factor-exposing microparticles in arterial and venous thrombosis, Semin. Thromb. Hemost. 41 (7) (2015) 718–727, http://dx.doi.org/10.1055/s-0035-1556047.
Table 1 Demographic and clinical characteristics of newborns. Parametera [unit]
Preterm infants (n = 23)
Term infants (n = 25)
Sex of infant (F/M) Gestational age [weeks] Birth weight [g] APGAR score 1st min 3rd min 5th min Maternal age [years] Gravidity Parity Model of delivery (V/C)
12/11 34 (32–36) 2130 (1640–2500) 8 (6–9) 9 (7–9) 9 (8–10) 29.5 (25–32) 2 (1–2) 1 (1–2) 7/16
10/15 40 (39–41)† 3480 (3280–3810)† 10 (9–10)† 10 (9–10)† 10 (10−10)† 28.5 (27–33) 2 (1–2) 1 (1–2) 16/9
Abbreviations: F: female, M: male, min: minute, V: vaginal delivery, C: cesarean section. a Values are median (Me) and (IQR) or number of newborns or mothers. † p b 0.05 in comparison to preterm infants (Mann–Whitney U test).
96
Letter to the Editors-in-Chief [5] S. Nomura, M. Shimizu, Clinical significance of procoagulant microparticles, J. Intensive Care 3 (1) (2015) 2, http://dx.doi.org/10.1186/s40560-014-0066-z. [6] C. Thornburg, S. Pipe, Neonatal thromboembolic emergencies, Semin. Fetal Neonatal Med. 11 (3) (2006) 198–206, http://dx.doi.org/10.1016/j.siny.2006.01.005. [7] P. Saracco, E. Parodi, C. Fabris, V. Cecinati, A.C. Molinari, P. Giordano, Management and investigation of neonatal thromboembolic events: genetic and acquired risk factors, Thromb. Res. 123 (6) (2009) 805–809, http://dx.doi.org/10.1016/j.thromres.2008. 12.002. [8] R. Bhat, P. Monagle, The preterm infant with thrombosis, Arch. Dis. Child. Fetal Neonatal Ed. 97 (6) (2012) 423–428, http://dx.doi.org/10.1136/archdischild-2011301142.
Piotr Korbal Department of Propedeutics of Medicine, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Poland Department of Neonatology and Neonatal Intensive Care, Jan Biziel University Hospital No 2, Bydgoszcz, Poland Corresponding author at: Department of Propedeutics of Medicine, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum in Bydgoszcz, 9 Skłodowskiej–Curie Str., 85-094 Bydgoszcz, Poland. E-mail address: [email protected]. Artur Słomka Department of Pathophysiology, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Poland Iwona Sadowska-Krawczenko Department of Neonatology and Neonatal Intensive Care, Jan Biziel University Hospital No 2, Bydgoszcz, Poland Ewa Żekanowska Department of Pathophysiology, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Poland Fig. 1. The levels of MPs-TF (1A) and total TF (1B) in the cord blood of preterm infants (n = 23) and term infants (n = 25).
[3] A. Słomka, M. Świtońska, W. Sinkiewicz, E. Żekanowska, Haemostatic factors do not account for worse outcomes from ischaemic stroke in patients with higher C-reactive protein concentrations, Ann. Clin. Biochem. (2016) http://dx.doi.org/10.1177/ 0004563216663775. [4] L. Badimon, R. Suades, E. Fuentes, I. Palomo, T. Padró, Role of platelet-derived microvesicles as crosstalk mediators in atherothrombosis and future pharmacology targets: a link between inflammation, atherosclerosis, and thrombosis, Front. Pharmacol. 7 (2016) 293, http://dx.doi.org/10.3389/fphar.2016.00293.
23 December 2016 Available online 1 March 2017