- Email: [email protected]
Despite weight status, children with obstructive sleep apnoea have an impaired exercise capacity
Oral Abstracts
49
and HC (0.21, 0.46) and were lower for the DEXA measures of percent fat (whole body 0.12, 0.35, abdominal 0.13, 0.37). Results followed a similar pattern for diastolic BP but the strength of the associations was weaker. Conclusion: DEXA measures of adiposity did not explain greater variance in BP than the simpler anthropometric measures of weight and central girth. These results suggest that in pre-pubertal children simple measures of anthropometry such as weight, standardised BMI and hip circumference are useful tools to assess BP in a clinical or research setting.
−0.36, −0.01), but the association was attenuated after adjustment for SB (ˇ: −0.14, 95% CI −0.33, 0.06). Conclusion: In addition to increasing physical activity, targeting reductions in sedentary behaviour (i.e. sitting time) may also contribute to improved cardio-metabolic health in overweight and obese children. *HIKCUPS was funded by the National Health & Medical Research Council of Australia (ID: 354101).
http://dx.doi.org/10.1016/j.orcp.2012.08.099
Despite weight status, children with obstructive sleep apnoea have an impaired exercise capacity
O098 Associations between sedentary behaviour, physical activity and cardio-metabolic health in overweight and obese children D. Cliff 1,∗ , A. Okely 1 , T. Burrows 2 , R. Jones 1 , P. Morgan 2 , C. Collins 2 , L. Baur 3 1 University
of Wollongong, Australia of Newcastle, Australia 3 University of Sydney, Australia 2 University
Aim: To examine associations between objectively measured sedentary behaviour (SB), moderate-to-vigorous physical activity (MVPA), and individual and clustered cardio-metabolic health outcomes in overweight and obese children. Method: Cross-sectional data from a clinical sample of 120 overweight and obese 5.5- to 10-year olds (8.3 ± 1.1 years, 62% girls, 74% obese) prior to participation in a treatment trial (the Hunter and Illawarra Kids Challenge Using Parent Support study*) were used. SB and MVPA were assessed during waking hours over 8 days using Actigraph accelerometers. Fasting blood was collected and associations with triglycerides, HDL cholesterol, glucose, insulin, systolic and diastolic blood pressure, and clustered cardio-metabolic health (cMet) were examined using linear regression. Models were adjusted for age, sex, waist circumference z-score, energy intake, saturated fat, fibre, weekly electronic screen time, accelerometer wear time, and MVPA or SB. Interactions with age, sex, or weight status were examined but were not significant (p > 0.1). Results: Independent of MVPA, SB was inversely associated with HDL cholesterol (ˇ: −0.29, 95% CI −0.52, −0.05). MVPA was inversely associated with diastolic blood pressure independent of SB (ˇ: −0.22, 95% CI −0.44, 0.01). MVPA was also inversely associated with cMet (ˇ: −0.19, 95% CI
http://dx.doi.org/10.1016/j.orcp.2012.08.100 O099
C. Evans 1,2,∗ , H. Waters 1,2
Selvadurai 1,2 , L.
Baur 1,2 , K.
1 University 2 The
of Sydney, Australia Children’s Hospital at Westmead, Australia
Aim: Although the effects of obesity on cardiopulmonary exercise responses have been studied in children, effects of obstructive sleep apnoea (OSA) have not. Since OSA is a co-morbidity of obesity and OSA alters ventricular dimensions and heart rate at rest and in sleep, we aimed to examine the effects of OSA versus obesity on cardiopulmonary responses to exercise. Method: Healthy weight and obese children were recruited. Polysomnography was used to diagnose OSA and exercise testing was undertaken on a cycle ergometer. Independent t-test analysis was performed between ‘No OSA’ and ‘OSA’ groups. Analysis of covariance was performed to evaluate cardiopulmonary responses attributed to obesity versus OSA. Results: Forty of 71 children (56%, mean age 10 yr) had OSA (mean BMI 27.0). Children with OSA had a lower cardiac output (8.9 ± 1.5 L/min vs 10.5 ± 1.3 L/min, p < 0.001) and oxygen consumption at peak exercise (20.82 ± 8.28 mL/kg/min vs 29.65 ± 9.21 mL/kg/min, p < 0.001). Peak exercise was achieved at 69 ± 31 W for children with OSA compared to 83 ± 22 W for those without (p = 0.06). There was no difference in ventilatory responses to exercise. Obese children fatigued earlier then healthy weight children but cardiopulmonary function was not affected by obesity. Conclusion: Independent of weight status, children with OSA have impaired cardiac responses to aerobic exercise. Obese children are exercise limited due to physical deconditioning, but if they have
50
Oral Abstracts
co-morbid OSA their exercise is further restricted due to an impaired cardiac response. http://dx.doi.org/10.1016/j.orcp.2012.08.101 O100 Obesity induced suppression of gastric satiety signals are only partially reversed by dietary change Kentish 1,∗ ,
S. Page 1,2
T.
O’Donnell 2 ,
G.
Wittert 1 ,
A.
1 Department
of Medicine, University of Adelaide, Adelaide, Australia 2 Nerve-Gut Research Laboratory, Royal Adelaide Hospital, Adelaide, Australia Aim: Diet induced obesity (DIO) decreases gastric vagal afferent satiety signalling (J Physiol 2012:590;209). Furthermore it switches the effect of leptin on vagal afferent mechanosensitivity from excitatory to inhibitory (Gastroenterology 2011:140;S332). Diet induced weight loss is seldom maintained, suggesting physiological mechanisms act to restore previous fat mass. Thus we sought to determine whether returning DIO mice to a standard laboratory diet (SLD) reverses the effect of DIO on gastric vagal afferent mechanosensitivity and restores the lean excitatory phenotype of leptin. Method: Female C57/BL6 mice (N = 12/group) were fed a SLD (5% fat) or a high fat diet (HFD; 35% fat) for 24 wks. A third group was fed HFD for 12 wks then SLD for a further 12 wks (RFD). Single fibre recordings of gastric vagal mechanoreceptors were obtained (J Neurophysiolv 2002:87;2095). Results: The mechanosensitivity of tension receptors from HFD and RFD mice were significantly reduced compared to SLD mice (p < 0.0001). There was no difference in the mechanosensitivity of mucosal receptors between any groups. In SLD mice, leptin (0.1—10 nM) caused a significant increase in mucosal receptor mechanosensitivity (p < 0.001) but had no effect on tension receptors. In HFD mice, leptin significantly reduced tension receptor mechanosensitivity (p < 0.001) but had no effect on mucosal receptors (p > 0.05). In RFD mice leptin caused potentiation of mucosal receptor mechanosensitivity (p < 0.01), however it also caused an inhibition of tension receptors (p < 0.01). Conclusion: Obesity induced effects on gastric satiety signals are not entirely reversible by changing the diet to a lower calorie diet, which may partly explain why weight loss is hard to achieve and maintain successfully. http://dx.doi.org/10.1016/j.orcp.2012.08.102
O101 Mechanisms underlying the effectiveness of the adjustable gastric band—–Insights from a rodent model B. Oldfield 1,∗ , J. Kampe 1 , A. Stephanidis 1 , W. Brown 2 1 Department
of Physiology, Monash University, Australia 2 Department of Surgery, Monash University, The Alfred Hospital, Melbourne, Australia Bariatric surgery remains the only effective treatment for morbid obesity. The adjustable gastric banding (AGB) is the most commonly of these procedures performed in Australia; however, the mechanism(s) underlying its efficacy are unclear. Aim: This study aims to elucidate the role of sensory neural pathways in mediating Adjustable Gastric Band (AGB)-induced satiety in a rodent model. Method: Adult male Sprague Dawley rats were fitted with an AGB, just below the gastrooesophageal junction. The AGB was optimally inflated and rats were allowed to survive for 2 hours post-inflation with or without capsaicin treatment (125 mg/kg) where the latter is responsible for the ablation of sensory nerve fibres travelling in the vagus nerve. Rats were then killed, perfused with aldehydes and their brains processed for the immunocytochemical localization of Fos, a marker of neural activity. A separate cohort of high fat fed (45% kcal from lipids) rats with bands fitted were pretreated with capsaicin and metabolic indices evaluated in inflated band and sham treated controls over a 4-week period. Results: Inflation of the AGB caused an increase in Fos activation in the nucleus of the solitary tract (NTS), the first synaptic relay of vagal sensory fibres in the brain, which was ameliorated in the captreated group. Capsaicin treatment also reduced the anorexic effects of the band as well as the band induced changes in body weight and fat mass after chronic inflation. Conclusion: These data support the notion that the AGB exerts its effects at least in part via vagal sensory mechanisms. http://dx.doi.org/10.1016/j.orcp.2012.08.103
49
and HC (0.21, 0.46) and were lower for the DEXA measures of percent fat (whole body 0.12, 0.35, abdominal 0.13, 0.37). Results followed a similar pattern for diastolic BP but the strength of the associations was weaker. Conclusion: DEXA measures of adiposity did not explain greater variance in BP than the simpler anthropometric measures of weight and central girth. These results suggest that in pre-pubertal children simple measures of anthropometry such as weight, standardised BMI and hip circumference are useful tools to assess BP in a clinical or research setting.
−0.36, −0.01), but the association was attenuated after adjustment for SB (ˇ: −0.14, 95% CI −0.33, 0.06). Conclusion: In addition to increasing physical activity, targeting reductions in sedentary behaviour (i.e. sitting time) may also contribute to improved cardio-metabolic health in overweight and obese children. *HIKCUPS was funded by the National Health & Medical Research Council of Australia (ID: 354101).
http://dx.doi.org/10.1016/j.orcp.2012.08.099
Despite weight status, children with obstructive sleep apnoea have an impaired exercise capacity
O098 Associations between sedentary behaviour, physical activity and cardio-metabolic health in overweight and obese children D. Cliff 1,∗ , A. Okely 1 , T. Burrows 2 , R. Jones 1 , P. Morgan 2 , C. Collins 2 , L. Baur 3 1 University
of Wollongong, Australia of Newcastle, Australia 3 University of Sydney, Australia 2 University
Aim: To examine associations between objectively measured sedentary behaviour (SB), moderate-to-vigorous physical activity (MVPA), and individual and clustered cardio-metabolic health outcomes in overweight and obese children. Method: Cross-sectional data from a clinical sample of 120 overweight and obese 5.5- to 10-year olds (8.3 ± 1.1 years, 62% girls, 74% obese) prior to participation in a treatment trial (the Hunter and Illawarra Kids Challenge Using Parent Support study*) were used. SB and MVPA were assessed during waking hours over 8 days using Actigraph accelerometers. Fasting blood was collected and associations with triglycerides, HDL cholesterol, glucose, insulin, systolic and diastolic blood pressure, and clustered cardio-metabolic health (cMet) were examined using linear regression. Models were adjusted for age, sex, waist circumference z-score, energy intake, saturated fat, fibre, weekly electronic screen time, accelerometer wear time, and MVPA or SB. Interactions with age, sex, or weight status were examined but were not significant (p > 0.1). Results: Independent of MVPA, SB was inversely associated with HDL cholesterol (ˇ: −0.29, 95% CI −0.52, −0.05). MVPA was inversely associated with diastolic blood pressure independent of SB (ˇ: −0.22, 95% CI −0.44, 0.01). MVPA was also inversely associated with cMet (ˇ: −0.19, 95% CI
http://dx.doi.org/10.1016/j.orcp.2012.08.100 O099
C. Evans 1,2,∗ , H. Waters 1,2
Selvadurai 1,2 , L.
Baur 1,2 , K.
1 University 2 The
of Sydney, Australia Children’s Hospital at Westmead, Australia
Aim: Although the effects of obesity on cardiopulmonary exercise responses have been studied in children, effects of obstructive sleep apnoea (OSA) have not. Since OSA is a co-morbidity of obesity and OSA alters ventricular dimensions and heart rate at rest and in sleep, we aimed to examine the effects of OSA versus obesity on cardiopulmonary responses to exercise. Method: Healthy weight and obese children were recruited. Polysomnography was used to diagnose OSA and exercise testing was undertaken on a cycle ergometer. Independent t-test analysis was performed between ‘No OSA’ and ‘OSA’ groups. Analysis of covariance was performed to evaluate cardiopulmonary responses attributed to obesity versus OSA. Results: Forty of 71 children (56%, mean age 10 yr) had OSA (mean BMI 27.0). Children with OSA had a lower cardiac output (8.9 ± 1.5 L/min vs 10.5 ± 1.3 L/min, p < 0.001) and oxygen consumption at peak exercise (20.82 ± 8.28 mL/kg/min vs 29.65 ± 9.21 mL/kg/min, p < 0.001). Peak exercise was achieved at 69 ± 31 W for children with OSA compared to 83 ± 22 W for those without (p = 0.06). There was no difference in ventilatory responses to exercise. Obese children fatigued earlier then healthy weight children but cardiopulmonary function was not affected by obesity. Conclusion: Independent of weight status, children with OSA have impaired cardiac responses to aerobic exercise. Obese children are exercise limited due to physical deconditioning, but if they have
50
Oral Abstracts
co-morbid OSA their exercise is further restricted due to an impaired cardiac response. http://dx.doi.org/10.1016/j.orcp.2012.08.101 O100 Obesity induced suppression of gastric satiety signals are only partially reversed by dietary change Kentish 1,∗ ,
S. Page 1,2
T.
O’Donnell 2 ,
G.
Wittert 1 ,
A.
1 Department
of Medicine, University of Adelaide, Adelaide, Australia 2 Nerve-Gut Research Laboratory, Royal Adelaide Hospital, Adelaide, Australia Aim: Diet induced obesity (DIO) decreases gastric vagal afferent satiety signalling (J Physiol 2012:590;209). Furthermore it switches the effect of leptin on vagal afferent mechanosensitivity from excitatory to inhibitory (Gastroenterology 2011:140;S332). Diet induced weight loss is seldom maintained, suggesting physiological mechanisms act to restore previous fat mass. Thus we sought to determine whether returning DIO mice to a standard laboratory diet (SLD) reverses the effect of DIO on gastric vagal afferent mechanosensitivity and restores the lean excitatory phenotype of leptin. Method: Female C57/BL6 mice (N = 12/group) were fed a SLD (5% fat) or a high fat diet (HFD; 35% fat) for 24 wks. A third group was fed HFD for 12 wks then SLD for a further 12 wks (RFD). Single fibre recordings of gastric vagal mechanoreceptors were obtained (J Neurophysiolv 2002:87;2095). Results: The mechanosensitivity of tension receptors from HFD and RFD mice were significantly reduced compared to SLD mice (p < 0.0001). There was no difference in the mechanosensitivity of mucosal receptors between any groups. In SLD mice, leptin (0.1—10 nM) caused a significant increase in mucosal receptor mechanosensitivity (p < 0.001) but had no effect on tension receptors. In HFD mice, leptin significantly reduced tension receptor mechanosensitivity (p < 0.001) but had no effect on mucosal receptors (p > 0.05). In RFD mice leptin caused potentiation of mucosal receptor mechanosensitivity (p < 0.01), however it also caused an inhibition of tension receptors (p < 0.01). Conclusion: Obesity induced effects on gastric satiety signals are not entirely reversible by changing the diet to a lower calorie diet, which may partly explain why weight loss is hard to achieve and maintain successfully. http://dx.doi.org/10.1016/j.orcp.2012.08.102
O101 Mechanisms underlying the effectiveness of the adjustable gastric band—–Insights from a rodent model B. Oldfield 1,∗ , J. Kampe 1 , A. Stephanidis 1 , W. Brown 2 1 Department
of Physiology, Monash University, Australia 2 Department of Surgery, Monash University, The Alfred Hospital, Melbourne, Australia Bariatric surgery remains the only effective treatment for morbid obesity. The adjustable gastric banding (AGB) is the most commonly of these procedures performed in Australia; however, the mechanism(s) underlying its efficacy are unclear. Aim: This study aims to elucidate the role of sensory neural pathways in mediating Adjustable Gastric Band (AGB)-induced satiety in a rodent model. Method: Adult male Sprague Dawley rats were fitted with an AGB, just below the gastrooesophageal junction. The AGB was optimally inflated and rats were allowed to survive for 2 hours post-inflation with or without capsaicin treatment (125 mg/kg) where the latter is responsible for the ablation of sensory nerve fibres travelling in the vagus nerve. Rats were then killed, perfused with aldehydes and their brains processed for the immunocytochemical localization of Fos, a marker of neural activity. A separate cohort of high fat fed (45% kcal from lipids) rats with bands fitted were pretreated with capsaicin and metabolic indices evaluated in inflated band and sham treated controls over a 4-week period. Results: Inflation of the AGB caused an increase in Fos activation in the nucleus of the solitary tract (NTS), the first synaptic relay of vagal sensory fibres in the brain, which was ameliorated in the captreated group. Capsaicin treatment also reduced the anorexic effects of the band as well as the band induced changes in body weight and fat mass after chronic inflation. Conclusion: These data support the notion that the AGB exerts its effects at least in part via vagal sensory mechanisms. http://dx.doi.org/10.1016/j.orcp.2012.08.103