Wednesday 23rd September, 2015A systematic review and multiple treatments meta-analysis to evaluate preoperative carbohydrate loading for enhancing recovery after elective surgery.MA Amer,1 MD Smith,1 JL McCall,1 GP Herbison21Department of Surgical Sciences, 2Department of Preventive and Social Medicine, Dunedin School of Medicine, University of Otago, DunedinSurgical stress causes increased insulin resistance, which may lead to hyperglycaemia, which in turn may prolong post-operative recovery through delayed wound healing and impaired immune function. The administration of a carbohydrate load preoperatively is postulated to mitigate this. Many randomised controlled trials (RCTs) have examined this, and have been summarised in three recent meta-analyses. However, these could not use all available data, as it is not possible to account for the different doses of carbohydrate administered and the different controls used in the trials, with pairwise meta-analysis. We conducted a multiple treatments (network) meta-analysis to incorporate all available data, regardless of differences in the intervention and control treatments.We systematically searched article databases for RCTs comparing preoperative carbohydrate treatment with water, a placebo drink, or fasting. We performed a four treatment network meta-analysis comparing two carbohydrate dose groups (low (10-44g); high (>45g)) with two control groups (fasting; water or placebo). Primary outcomes were length of hospital stay and post-operative complication rate. Secondary outcomes included post-operative insulin resistance, vomiting, fatigue and well-being.We included 34 trials, involving 2,569 participants. Compared to fasting, preoperative low dose and high dose carbohydrate administration decreased post-operative length of stay by 0.6 days (95% confidence interval (CI) 0.1-1, P=0.01; back-transformed standardised mean difference) and 0.3 days (95% CI 0.1-0.5, P=0.005) respectively. There was no significant decrease in length of stay compared to water or placebo. We found no significant difference in post-operative complication rates, or any of the secondary outcomes, between the carbohydrate and control groups.Carbohydrate administration before elective surgery conferred a small reduction in length of stay only when compared to fasting, but no significant difference when compared to water or placebo. No other significant effect on post-operative outcomes was found.Supported by a Dunedin School of Medicine Dunbar Scholarship, a Royal Australasian College of Surgeons Foundation for Surgery New Zealand Scholarship, and the Health Research Council of New Zealand.Cardiovascular microRNAs in diagnosis and therapeutic intervention of diabetic heart diseaseS Rawal,1 E Munasinghe,1 P Manning,2 R Katare11Department of Physiology, University of Otago, Dunedin, New Zealand, 2Department of Medicine, Dunedin Hospital, DunedinDiabetic heart disease (DHD) is often unrecognised in subclinical stage due to absence of pathognomonic signs, thereby restricting timeous diagnosis and management of disease. Recently, microRNAs (miRs) are gaining popularity as diagnostics and key regulators in the pathophysiology of several diseases including cardiovascular diseases. However, the diagnostic potential and pathophysiological role of miRs in DHD is still unknown.RNA was extracted from plasma (n=14) of people with diabetes and age- matched non-diabetic volunteers with no history of heart disease. QPCR analyses revealed marked dysregulation of target-miRs (miR-1,-126,-132,-133 and -499) in diabetic plasma which was also dependent on duration of diabetes (P<0.05, unpaired student t test). To further answer, whether modulation of circulating miRs has a correlation with etiology of DHD, miR expressions were studied in cardiac tissues (n=10) of 8-32 weeks old type 2 diabetic (Db/db) and non-diabetic mice. Remarkably, all investigated miRs and their target proteins were dysregulated in diabetic myocardium, starting from 8-weeks of age (P<0.05). Importantly, echocardiography and immunohistochemical analyses did not reveal any noticeable changes in diabetic mice until 20-weeks of age (P<0.001). These findings suggest that miRs are early modulators of DHD and can be explored as therapeutic interventions for prompt management of DHD. In line with these results, we elicited in vitro modulation of two target-miRs (miR-126,-132) to explore their therapeutic potential in diabetic state. It was demonstrated that restoration in expression of both miRs in HUVECs abrogated the deleterious effects against high-glucose-induced impaired angiogenesis, proliferation and cell survival (P<0.05). Current studies aim to determine the therapeutic potential of other miRs using HL-1 cardiomyocytes.Overall, these findings provide the first evidence that miRs can be used as a novel diagnostic tool for early detection of DHD. It also opens up intriguing ways to develop miR-based therapies for management of DHD.Supported by a University of Otago Doctoral Scholarship, Department of Physiology, Heart Foundation NZ, Otago Medical Research Foundation and New Zealand Society for the Study of DiabetesInfluence of obesity on energy expenditure during brisk walking in adults.L Mabire, H Mulligan, R Mani, D BaxterCentre for Health, Activity, and Rehabilitation Research, School of Physiotherapy, University of Otago, DunedinThe twentieth anniversary of the physical activity guidelines of 150 minutes each week of moderate intensity activity was marked in 2015. The guidelines represent the time required for a 70 kg man to expend 1,000 kcal. With the global growth in obesity, the average man is now 90 kg. As energy expenditure increases with body mass, obese adults could be expending significantly more than the recommended 1,000 kcal/week. This increased exposure to activity could contribute to the poor outcomes and compliance experienced by this population. The purpose of this observational study was to quantify how indices of obesity, primarily body mass; BMI; waist circumference; and, body composition influence energy expenditure during brisk walking in adults.A sample of 62 adults (males=18, females=44) was purposively recruited to populate five subgroups of 10 to 13 participants each, sorted by BMI to facilitate equal distribution of BMIs: healthy-weight (BMI 19.5-24.9 kg/m2); overweight (BMI 25-29.9 kg/m2); obese I (BMI 30-34.9 kg/m2); obese II (BMI 35-39.9 kg/m2); obese III (BMI> 40 kg/m2). The energy cost of walking (kcal/minute) was determined using indirect calorimetry whilst walking on a treadmill at 4.8 km/h for 15 minutes. Bivariate Pearsons correlation tests and linear regression analysis (P \u2264 0.05) were used to establish whether indices of obesity are associated with energy expenditure.Preliminary results show energy cost of walking was strongly correlated with body mass, BMI, waist circumference and fat mass (R=0.77 to 0.86, P <0.001). Moderate correlation was observed with body fat percentage and fat-free mass. Backward multiple regression indicates that energy expenditure can be accurately predicted using fat mass, fat-free mass, heart rate and body mass (R2=0.93, P < 0.001).The energy cost of walking increases as obesity level rises. As physical activity prescription is based on expending 1,000 kcal/wk, obese adults are potentially significantly overdosing on activity. This data could be used to accurately prescribe a safe and effective individualised dose of exercise for obese adults.Supported by a grant from the Physiotherapy New Zealand Scholarship Trust Fund.Two heads are better than one: Dendritic cells and B cells enhance the anti-tumour immune response compared with dendritic cells aloneML Grant,1 C Jackson,2 SL Young SL11Pathology Department, Dunedin School of Medicine, University of Otago, Dunedin. 2Oncology Department, Dunedin Hospital, University of Otago, Dunedin.The dendritic cell (DC) is well established as the key professional antigen- presenting cell (APC) for priming na\u00efve T cells and, in theory, should be the APC of choice in T cell adoptive cell therapy (ACT). However robust clinical results using T cells primed by DC for ACT remain elusive. Varying methodologies and conditions between groups studying the anti-tumor response of various APCs makes meta-analysis difficult.In this study the in vitro anti-tumor response (proliferation, cytokine profile, cytotoxicity) of T cells primed by one, two or three tumour-lysate-pulsed APCs (DCs, macrophages and B cells) were compared using flow cytometry, ELISA, VITAL and ELISPOT assays. The OVA transgenic (OT) mouse system with the T cell receptor (OT-I CD8+ and OT-II CD4+) responding to specific peptides of the model antigen ovalbumin was employed as the read out.Granulocyte macrophage-colony stimulating factor (GM-CSF)-differentiated bone marrow fraction of B16OVA tumor lysate (sFTL) was superior to macrophages at stimulating OT-I CD8+ T cell proliferation (P < 0.05, unpaired t-tests). A synergistic proliferation response was achieved when GMDCs and B cells were used in combination to present sFTL to CD8+ OT-I T cells (P < 0.05, unpaired t-tests). This synergistic response was not seen seen in OT-II CD4+ T cells. The IFN-\u03b3 response to antigen presentation by a GMDC+B cellwas also superior to that of GMDCs alone in both CD4+ and CD8+ T cell co-cultures (P < 0.05, unpaired t-tests). The in vitro cytotoxicity assay to test the T cells tumor cell killing ability showed a trend approaching significance, suggesting that the combination of two or more APCs yields more cytotoxic T cells than GMDCs alone.The literature has multiple studies demonstrating in vivo cooperation between DC and macrophages and DC and B cells. Given that in vivo DC do not present tumor antigen in isolation, these results suggest that a single APC approach may be unnecessarily limiting the potential of ex-vivo APC adoptive cell therapy.Supported a Freemasons Southern Oncology PhD FellowshipImpact on glycaemia of walking after eating and standard physical activity advice in type 2 diabetes: a randomised crossover trial.AN Reynolds,1,2 B Venn,1 S Williams,3 J Mann1,2,41Department of Human Nutrition, University of Otago, Dunedin, 2Edgar National Centre for Diabetes and Obesity Research, Dunedin, 3Department of Preventive and Social Medicine, 4Faculty of Medicine, University of Otago, DunedinAdvice regarding physical activity is an accepted component of treatment for type 2 diabetes (T2DM). Physical activity has been shown to reduce blood glucose levels, may reduce cardiovascular disease and may help reduce body fatness in overweight or obese people with T2DM. Current T2DM physical activity guidelines recommend walking 30 minutes each day, but do not specify when physical activity should be taken within the day.To determine the effects of a postprandial physical activity prescription on glycaemic control we recruited 41 T2DM adults (mean \u00b1 SD, age 59.9 \u00b1 9.81 years, hbA1c 58.9 \u00b1 15.50 mmol/mol) into a randomised cross-over trial.Interventions were walking 10 minutes after each meal compared with walking continuously for 30 minutes at any time of the day, for periods of two weeks.Continuous glucose monitors were used to calculate the incremental area under the curve (iAUC) for each meal and the sum of total meals. Biochemical and anthropometric measures were taken pre and post interventions. After adjustment for intervention order, iAUC (mmol/L.min) was significantly lower when walking after eating (RR 0.87; 95% CI 0.78, 0.99; P = 0.03), driven by a highly significant difference in the evening meal (RR 0.78; 95% CI 0.67, 0.91; P < 0.001). Changes in biochemical markers and anthropometric markers of body weight and body fatness did not differ between the two-week interventions. Compliance with walking prescriptions between interventions did not differ with 49% of walks undertaken.Glycaemic improvements were observed when walking after eating compared with current physical activity guidelines that do not specify when in the day to walk. Walking after eating appears a practical means of interpreting physical activity guidelines for those wishing to improve glycaemic control with physical activity.This trial is registered in the Australian New Zealand Clinical Trials Registry: ACTRN12613000832774, and was funded by the The New Zealand Artificial Limbs Service and a Department of Human Nutrition PBRF grant.Disruption of NPY neuron developmental mechanisms by maternal obesity and IL-6T Sanders, C JasoniDepartment of Anatomy and Centre for Neuroendocrinology, Otago School of Medical Sciences, University of Otago, DunedinA correlation has been shown, in humans and animal models, between maternal obesity during pregnancy, and obesity in the offspring. Furthermore, the ability of body weight regulating neurons in the arcuate nucleus of the hypothalamus (ARC) to innervate their targets is disrupted in the offspring of obese mothers. The mechanism behind this is unknown. Maternal obesity is associated with increases in inflammatory cytokines, including interleukin-6 (IL-6), in both the maternal and fetal circulation. We hypothesise that an increase in cytokine exposure disrupts the ability of ARC neurons to innervate their targets.We first investigated a role for the axon guidance factor Netrin-1 in the fetal development of ARC weight regulating Neuropeptide Y (NPY) neurons under normal circumstances. In mice, using in situ hybridisation, we have shown that in late gestation Netrin-1 is expressed in a pattern consistent with guiding NPY axons to their targets. Additionally, using a primary culture model we found NPY neurons respond to Netrin-1 by increased elaboration of their growth cones (118 \u00b1 12.75\u03bcm2 surface area, mean \u00b1 SEM) when compared to controls (74 \u00b1 9.92 \u03bcm2 surface area, P < 0.05, two-tailed t-test, n=9).Secondly, we used both in vivo and in vitro methods to evaluate whether changes in Netrin-1 signaling might account for altered NPY target innervation in maternal obesity. We used a mouse model of maternal obesity to show that fetal ARC expression of the Netrin-1 receptor Dcc was significantly increased in vivo (1.45 fold \u00b1 0.18, P < 0.05, n=6) when compared with controls. We then replicated this finding in vitro by exposure of mouse fetal ARC to 100 ng/mL IL-6 (n=4, Dcc fold increase 2.1 \u00b1 0.5, P < 0.05).These data support a mechanism by which increased IL-6 during maternal obesity can disrupt the normal fetal development of neural feeding circuitry via Netrin-1 signaling.Supported by a New Zealand Lottery Health grant, a Health Research Council of New Zealand grant, and a Gravida: National Centre for Growth and Development PhD scholarship\r\n

Wednesday 23rd September, 2015A systematic review and multiple treatments meta-analysis to evaluate preoperative carbohydrate loading for enhancing recovery after elective surgery.MA Amer,1 MD Smith,1 JL McCall,1 GP Herbison21Department of Surgical Sciences, 2Department of Preventive and Social Medicine, Dunedin School of Medicine, University of Otago, DunedinSurgical stress causes increased insulin resistance, which may lead to hyperglycaemia, which in turn may prolong post-operative recovery through delayed wound healing and impaired immune function. The administration of a carbohydrate load preoperatively is postulated to mitigate this. Many randomised controlled trials (RCTs) have examined this, and have been summarised in three recent meta-analyses. However, these could not use all available data, as it is not possible to account for the different doses of carbohydrate administered and the different controls used in the trials, with pairwise meta-analysis. We conducted a multiple treatments (network) meta-analysis to incorporate all available data, regardless of differences in the intervention and control treatments.We systematically searched article databases for RCTs comparing preoperative carbohydrate treatment with water, a placebo drink, or fasting. We performed a four treatment network meta-analysis comparing two carbohydrate dose groups (low (10-44g); high (>45g)) with two control groups (fasting; water or placebo). Primary outcomes were length of hospital stay and post-operative complication rate. Secondary outcomes included post-operative insulin resistance, vomiting, fatigue and well-being.We included 34 trials, involving 2,569 participants. Compared to fasting, preoperative low dose and high dose carbohydrate administration decreased post-operative length of stay by 0.6 days (95% confidence interval (CI) 0.1-1, P=0.01; back-transformed standardised mean difference) and 0.3 days (95% CI 0.1-0.5, P=0.005) respectively. There was no significant decrease in length of stay compared to water or placebo. We found no significant difference in post-operative complication rates, or any of the secondary outcomes, between the carbohydrate and control groups.Carbohydrate administration before elective surgery conferred a small reduction in length of stay only when compared to fasting, but no significant difference when compared to water or placebo. No other significant effect on post-operative outcomes was found.Supported by a Dunedin School of Medicine Dunbar Scholarship, a Royal Australasian College of Surgeons Foundation for Surgery New Zealand Scholarship, and the Health Research Council of New Zealand.Cardiovascular microRNAs in diagnosis and therapeutic intervention of diabetic heart diseaseS Rawal,1 E Munasinghe,1 P Manning,2 R Katare11Department of Physiology, University of Otago, Dunedin, New Zealand, 2Department of Medicine, Dunedin Hospital, DunedinDiabetic heart disease (DHD) is often unrecognised in subclinical stage due to absence of pathognomonic signs, thereby restricting timeous diagnosis and management of disease. Recently, microRNAs (miRs) are gaining popularity as diagnostics and key regulators in the pathophysiology of several diseases including cardiovascular diseases. However, the diagnostic potential and pathophysiological role of miRs in DHD is still unknown.RNA was extracted from plasma (n=14) of people with diabetes and age- matched non-diabetic volunteers with no history of heart disease. QPCR analyses revealed marked dysregulation of target-miRs (miR-1,-126,-132,-133 and -499) in diabetic plasma which was also dependent on duration of diabetes (P<0.05, unpaired student t test). To further answer, whether modulation of circulating miRs has a correlation with etiology of DHD, miR expressions were studied in cardiac tissues (n=10) of 8-32 weeks old type 2 diabetic (Db/db) and non-diabetic mice. Remarkably, all investigated miRs and their target proteins were dysregulated in diabetic myocardium, starting from 8-weeks of age (P<0.05). Importantly, echocardiography and immunohistochemical analyses did not reveal any noticeable changes in diabetic mice until 20-weeks of age (P<0.001). These findings suggest that miRs are early modulators of DHD and can be explored as therapeutic interventions for prompt management of DHD. In line with these results, we elicited in vitro modulation of two target-miRs (miR-126,-132) to explore their therapeutic potential in diabetic state. It was demonstrated that restoration in expression of both miRs in HUVECs abrogated the deleterious effects against high-glucose-induced impaired angiogenesis, proliferation and cell survival (P<0.05). Current studies aim to determine the therapeutic potential of other miRs using HL-1 cardiomyocytes.Overall, these findings provide the first evidence that miRs can be used as a novel diagnostic tool for early detection of DHD. It also opens up intriguing ways to develop miR-based therapies for management of DHD.Supported by a University of Otago Doctoral Scholarship, Department of Physiology, Heart Foundation NZ, Otago Medical Research Foundation and New Zealand Society for the Study of DiabetesInfluence of obesity on energy expenditure during brisk walking in adults.L Mabire, H Mulligan, R Mani, D BaxterCentre for Health, Activity, and Rehabilitation Research, School of Physiotherapy, University of Otago, DunedinThe twentieth anniversary of the physical activity guidelines of 150 minutes each week of moderate intensity activity was marked in 2015. The guidelines represent the time required for a 70 kg man to expend 1,000 kcal. With the global growth in obesity, the average man is now 90 kg. As energy expenditure increases with body mass, obese adults could be expending significantly more than the recommended 1,000 kcal/week. This increased exposure to activity could contribute to the poor outcomes and compliance experienced by this population. The purpose of this observational study was to quantify how indices of obesity, primarily body mass; BMI; waist circumference; and, body composition influence energy expenditure during brisk walking in adults.A sample of 62 adults (males=18, females=44) was purposively recruited to populate five subgroups of 10 to 13 participants each, sorted by BMI to facilitate equal distribution of BMIs: healthy-weight (BMI 19.5-24.9 kg/m2); overweight (BMI 25-29.9 kg/m2); obese I (BMI 30-34.9 kg/m2); obese II (BMI 35-39.9 kg/m2); obese III (BMI> 40 kg/m2). The energy cost of walking (kcal/minute) was determined using indirect calorimetry whilst walking on a treadmill at 4.8 km/h for 15 minutes. Bivariate Pearsons correlation tests and linear regression analysis (P \u2264 0.05) were used to establish whether indices of obesity are associated with energy expenditure.Preliminary results show energy cost of walking was strongly correlated with body mass, BMI, waist circumference and fat mass (R=0.77 to 0.86, P <0.001). Moderate correlation was observed with body fat percentage and fat-free mass. Backward multiple regression indicates that energy expenditure can be accurately predicted using fat mass, fat-free mass, heart rate and body mass (R2=0.93, P < 0.001).The energy cost of walking increases as obesity level rises. As physical activity prescription is based on expending 1,000 kcal/wk, obese adults are potentially significantly overdosing on activity. This data could be used to accurately prescribe a safe and effective individualised dose of exercise for obese adults.Supported by a grant from the Physiotherapy New Zealand Scholarship Trust Fund.Two heads are better than one: Dendritic cells and B cells enhance the anti-tumour immune response compared with dendritic cells aloneML Grant,1 C Jackson,2 SL Young SL11Pathology Department, Dunedin School of Medicine, University of Otago, Dunedin. 2Oncology Department, Dunedin Hospital, University of Otago, Dunedin.The dendritic cell (DC) is well established as the key professional antigen- presenting cell (APC) for priming na\u00efve T cells and, in theory, should be the APC of choice in T cell adoptive cell therapy (ACT). However robust clinical results using T cells primed by DC for ACT remain elusive. Varying methodologies and conditions between groups studying the anti-tumor response of various APCs makes meta-analysis difficult.In this study the in vitro anti-tumor response (proliferation, cytokine profile, cytotoxicity) of T cells primed by one, two or three tumour-lysate-pulsed APCs (DCs, macrophages and B cells) were compared using flow cytometry, ELISA, VITAL and ELISPOT assays. The OVA transgenic (OT) mouse system with the T cell receptor (OT-I CD8+ and OT-II CD4+) responding to specific peptides of the model antigen ovalbumin was employed as the read out.Granulocyte macrophage-colony stimulating factor (GM-CSF)-differentiated bone marrow fraction of B16OVA tumor lysate (sFTL) was superior to macrophages at stimulating OT-I CD8+ T cell proliferation (P < 0.05, unpaired t-tests). A synergistic proliferation response was achieved when GMDCs and B cells were used in combination to present sFTL to CD8+ OT-I T cells (P < 0.05, unpaired t-tests). This synergistic response was not seen seen in OT-II CD4+ T cells. The IFN-\u03b3 response to antigen presentation by a GMDC+B cellwas also superior to that of GMDCs alone in both CD4+ and CD8+ T cell co-cultures (P < 0.05, unpaired t-tests). The in vitro cytotoxicity assay to test the T cells tumor cell killing ability showed a trend approaching significance, suggesting that the combination of two or more APCs yields more cytotoxic T cells than GMDCs alone.The literature has multiple studies demonstrating in vivo cooperation between DC and macrophages and DC and B cells. Given that in vivo DC do not present tumor antigen in isolation, these results suggest that a single APC approach may be unnecessarily limiting the potential of ex-vivo APC adoptive cell therapy.Supported a Freemasons Southern Oncology PhD FellowshipImpact on glycaemia of walking after eating and standard physical activity advice in type 2 diabetes: a randomised crossover trial.AN Reynolds,1,2 B Venn,1 S Williams,3 J Mann1,2,41Department of Human Nutrition, University of Otago, Dunedin, 2Edgar National Centre for Diabetes and Obesity Research, Dunedin, 3Department of Preventive and Social Medicine, 4Faculty of Medicine, University of Otago, DunedinAdvice regarding physical activity is an accepted component of treatment for type 2 diabetes (T2DM). Physical activity has been shown to reduce blood glucose levels, may reduce cardiovascular disease and may help reduce body fatness in overweight or obese people with T2DM. Current T2DM physical activity guidelines recommend walking 30 minutes each day, but do not specify when physical activity should be taken within the day.To determine the effects of a postprandial physical activity prescription on glycaemic control we recruited 41 T2DM adults (mean \u00b1 SD, age 59.9 \u00b1 9.81 years, hbA1c 58.9 \u00b1 15.50 mmol/mol) into a randomised cross-over trial.Interventions were walking 10 minutes after each meal compared with walking continuously for 30 minutes at any time of the day, for periods of two weeks.Continuous glucose monitors were used to calculate the incremental area under the curve (iAUC) for each meal and the sum of total meals. Biochemical and anthropometric measures were taken pre and post interventions. After adjustment for intervention order, iAUC (mmol/L.min) was significantly lower when walking after eating (RR 0.87; 95% CI 0.78, 0.99; P = 0.03), driven by a highly significant difference in the evening meal (RR 0.78; 95% CI 0.67, 0.91; P < 0.001). Changes in biochemical markers and anthropometric markers of body weight and body fatness did not differ between the two-week interventions. Compliance with walking prescriptions between interventions did not differ with 49% of walks undertaken.Glycaemic improvements were observed when walking after eating compared with current physical activity guidelines that do not specify when in the day to walk. Walking after eating appears a practical means of interpreting physical activity guidelines for those wishing to improve glycaemic control with physical activity.This trial is registered in the Australian New Zealand Clinical Trials Registry: ACTRN12613000832774, and was funded by the The New Zealand Artificial Limbs Service and a Department of Human Nutrition PBRF grant.Disruption of NPY neuron developmental mechanisms by maternal obesity and IL-6T Sanders, C JasoniDepartment of Anatomy and Centre for Neuroendocrinology, Otago School of Medical Sciences, University of Otago, DunedinA correlation has been shown, in humans and animal models, between maternal obesity during pregnancy, and obesity in the offspring. Furthermore, the ability of body weight regulating neurons in the arcuate nucleus of the hypothalamus (ARC) to innervate their targets is disrupted in the offspring of obese mothers. The mechanism behind this is unknown. Maternal obesity is associated with increases in inflammatory cytokines, including interleukin-6 (IL-6), in both the maternal and fetal circulation. We hypothesise that an increase in cytokine exposure disrupts the ability of ARC neurons to innervate their targets.We first investigated a role for the axon guidance factor Netrin-1 in the fetal development of ARC weight regulating Neuropeptide Y (NPY) neurons under normal circumstances. In mice, using in situ hybridisation, we have shown that in late gestation Netrin-1 is expressed in a pattern consistent with guiding NPY axons to their targets. Additionally, using a primary culture model we found NPY neurons respond to Netrin-1 by increased elaboration of their growth cones (118 \u00b1 12.75\u03bcm2 surface area, mean \u00b1 SEM) when compared to controls (74 \u00b1 9.92 \u03bcm2 surface area, P < 0.05, two-tailed t-test, n=9).Secondly, we used both in vivo and in vitro methods to evaluate whether changes in Netrin-1 signaling might account for altered NPY target innervation in maternal obesity. We used a mouse model of maternal obesity to show that fetal ARC expression of the Netrin-1 receptor Dcc was significantly increased in vivo (1.45 fold \u00b1 0.18, P < 0.05, n=6) when compared with controls. We then replicated this finding in vitro by exposure of mouse fetal ARC to 100 ng/mL IL-6 (n=4, Dcc fold increase 2.1 \u00b1 0.5, P < 0.05).These data support a mechanism by which increased IL-6 during maternal obesity can disrupt the normal fetal development of neural feeding circuitry via Netrin-1 signaling.Supported by a New Zealand Lottery Health grant, a Health Research Council of New Zealand grant, and a Gravida: National Centre for Growth and Development PhD scholarship\r\n