Prevention of early catch-up growth reversed the development of glucose intolerance and obesity in our mouse model of LBW-associated diabetes.

Peroxisome proliferator activator receptor-␥ coactivator 1 (PGC-1) is a major candidate gene for diabetes-related metabolic phenotypes, contributing to decreased expression of nuclear-encoded mitochondrial genes in muscle and adipose tissue. We have demonstrated that muscle expression of PGC-1␣ and -␤ is reduced in both genetic (Lep ob /Lep ob ) and acquired obesity (high fat diet). In C57BL6 mice, muscle PGC-1␣ expression decreased by 43% (p < 0.02) after 1 week of a high fat diet and persisted more than 11 weeks. In contrast, PGC-1␣ reductions were not sustained in obesity-resistant A/J mice. To identify mediators of obesity-linked reductions in PGC-1, we tested the effects of cellular nutrients in C2C12 myotubes. Although overnight exposure to high insulin, glucose, glucosamine, or amino acids had no effect, saturated fatty acids potently reduced PGC-1␣ and -␤ mRNA expression. Palmitate decreased PGC-1␣ and -␤ expression by 38% (p ‫؍‬ 0.01) and 53% (p ‫؍‬ 0.006); stearate similarly decreased expression of PGC-1␣ and -␤ by 22% (p ‫؍‬ 0.02) and 39% (p ‫؍‬ 0.02). These effects were mediated at a transcriptional level, as indicated by an 11-fold reduction of PGC-1␣ promoter activity by palmitate and reversal of effects by histone deacetylase inhibition. Palmitate also (a) reduced expression of tricarboxylic acid cycle and oxidative phosphorylation mitochondrial genes and (b) reduced oxygen consumption. These effects were reversed by overexpression of PGC-1␣ or -␤, indicating PGC-1 dependence. Palmitate effects also required p38 MAPK, as demonstrated by 1) palmitate-induced increase in p38 MAPK phosphorylation, 2) reversal of palmitate effects on PGC-1 and mitochondrial gene expression by p38 MAPK inhibitors, and 3) reversal of palmitate effects by small interfering RNA-mediated decreases in p38␣ MAPK. These data indicate that obesity and saturated fatty acids decrease PGC-1 and mitochondrial gene expression and function via p38 MAPK-dependent transcriptional pathways.

Our objectives were to study risk factors and post-operative outcomes associated with excessive post-operative bleeding in pediatric cardiac surgeries performed using cardiopulmonary bypass (CPB) support. A retrospective observational study was undertaken, and all consecutive pediatric heart surgeries over 1 year period were studied. Excessive post-operative bleeding was defined as 10 ml/kg/h of chest tube output for 1 h or 5 ml/kg/h for three consecutive hours in the first 12 h of pediatric cardiac intensive care unit (PCICU) stay. Risk factors including demographics, complexity of cardiac defect, CPB parameters, hematological studies, and post-operative morbidity and mortality were evaluated for excessive bleeding. 253 patients were studied, and 107 (42 %) met the criteria for excessive bleeding. Bayesian model averaging revealed that greater volume of blood products transfusion during CPB was significantly associated with excessive bleeding. Multiple logistic regression analysis of blood products transfusion revealed that increased volume of packed red blood cells (PRBCs) administration for CPB prime and during CPB was significantly associated with excessive bleeding (p = 0.028 and p = 0.0012, respectively). Proportional odds logistic regression revealed that excessive bleeding was associated with greater time to achieve negative fluid balance, prolonged mechanical ventilation, and duration of PCICU stay (p < 0.001) after adjusting for multiple parameters. A greater volume of blood products administration, especially PRBCs transfusion for CPB prime, and during the CPB period is associated with excessive post-operative bleeding. Excessive bleeding is associated with worse post-operative outcomes.

Aims/hypothesis Observational studies in humans suggest that low birthweight may decrease the risk of type 1 diabetes, but the mechanism is unknown. We hypothesised that antenatal undernutrition would decrease the incidence of type 1 diabetes in non-obese diabetic (NOD) mice. Materials and methods A 40% restriction of energy intake was applied to pregnant NOD dams from day 12.5 to day 18.5 of gestation, resulting in intrauterine growth retardation of offspring. All mice were fed a standard diet after weaning. Control and undernourished female offspring were followed to assess diabetes incidence. Male NOD mice were treated with cyclophosphamide to accelerate development of diabetes. Glucose homeostasis, body composition and pancreatic histology were compared in control and undernourished offspring. Results Mean birthweight was lower in undernourished than in control mice (p=0.00003). At 24 weeks of age, the cumulative incidence of spontaneous diabetes in female mice was 73% in control and 48% in undernourished mice (p=0.003). In cyclophosphamide-treated male mice, antenatal undernutrition also tended to reduce the development of diabetes (p=0.058). Maternal leptin levels were lower in undernourished dams on day 18.5 of pregnancy (p=0.039), while postnatal leptin levels were significantly higher in undernourished offspring at 4, 20 and 27 weeks of life (p<0.05). Beta cell mass was similar in both groups (control = 0.4 mg; undernourished = 0.54 mg; p=0.24). Histological evidence of apoptosis at 20 weeks was greater in control than in undernourished mice (control = 6.3± 1.4%; undernourished = 4.2±0.3%, p=0.05). Conclusions/interpretation Antenatal undernutrition reduces the incidence of diabetes in NOD mice, perhaps via alterations in apoptosis.