Objectives To assess the precision magnetic resonance imaging (MRI) in the neonate and determine if there is an early maternal influence on the pattern of neonatal fat deposition in the offspring of mothers with gestational diabetes (GDM) and obesity compared with the offspring of normal weight women. Study design 25 neonates, born to normal weight mothers (n=13) and to obese mothers with GDM (n=12), underwent MRI for measurement of subcutaneous and intra-abdominal fat and magnetic resonance spectroscopy for the measurement of intrahepatocellular (IHCL) fat at 1-3 weeks of age. Results Infants born to obese/GDM mothers had a mean 68% increase in IHCL compared with infants born to normal weight mothers. For all infants, IHCL correlated with maternal pre-pregnancy BMI but not with subcutaneous adiposity. Conclusion Deposition of liver fat in the neonate correlates highly with maternal BMI. This finding may have implications for understanding the developmental origins of childhood NAFLD.

Key pointsr Adults who were affected by intrauterine growth restriction (IUGR) suffer from reductions in muscle mass, which may contribute to insulin resistance and the development of diabetes.r We demonstrate slower hindlimb linear growth and muscle protein synthesis rates that match the reduced hindlimb blood flow and oxygen consumption rates in IUGR fetal sheep. These adaptations resulted in hindlimb blood flow rates in IUGR that were similar to control fetuses on a weight-specific basis.r Net hindlimb glucose uptake and lactate output rates were similar between groups, whereas amino acid uptake was significantly lower in IUGR fetal sheep.r Among all fetuses, blood O 2 saturation and plasma glucose, insulin and insulin-like growth factor-1 were positively associated and norepinephrine was negatively associated with hindlimb weight.r These results further our understanding of the metabolic and hormonal adaptations to reduced oxygen and nutrient supply with placental insufficiency that develop to slow hindlimb growth and muscle protein accretion.Abstract Reduced skeletal muscle mass in the fetus with intrauterine growth restriction (IUGR) persists into adulthood and may contribute to increased metabolic disease risk. To determine how placental insufficiency with reduced oxygen and nutrient supply to the fetus affects hindlimb blood flow, substrate uptake and protein accretion rates in skeletal muscle, late gestation control (CON) (n = 8) and IUGR (n = 13) fetal sheep were catheterized with aortic and femoral catheters and a flow transducer around the external iliac artery. Muscle protein kinetic rates were measured using isotopic tracers. Hindlimb weight, linear growth rate, muscle protein accretion rate and fractional synthetic rate were lower in IUGR compared to CON (P < 0.05). Absolute hindlimb blood flow was reduced in IUGR (IUGR: 32.9 ± 5.6 ml min −1 ; CON: 60.9 ± 6.5 ml min −1 ; P < 0.005), although flow normalized to hindlimb weight was similar between groups. Hindlimb oxygen consumption rate was lower in IUGR (IUGR: 10.4 ± 1.4 μmol min −1 100 g −1 ; CON: 14.7 ± 1.3 μmol min −1 100 g −1 ; P < 0.05). Hindlimb glucose uptake and lactate output rates were similar between groups, whereas amino acid uptake was lower in IUGR (IUGR: 1.3 ± 0.5 μmol min −1 100 g −1 ; CON: 2.9 ± 0.2 μmol min −1 100 g −1 ; P < 0.05). Blood O 2 saturation (r 2 = 0.80, P < 0.0001) and plasma glucose (r 2 = 0.68, P < 0.0001), insulin (r 2 = 0.40, P < 0.005) and insulin-like growth factor (IGF)-1 (r 2 = 0.80, P < 0.0001) were positively associated and norepinephrine (r 2 = 0.59, P < 0.0001) was negatively associated with hindlimb weight. Slower hindlimb linear growth and muscle protein synthesis rates match reduced hindlimb blood flow and oxygen consumption rates in the IUGR fetus. Metabolic adaptations to slow hindlimb growth are probably hormonally-mediated by mechanisms that include increased fetal norepinephrine and reduced IGF-1 and insulin.

Background: Cardiovascular disease (CVD) is the leading cause of mortality in type 1 diabetes (T1D) and relates strongly to insulin resistance (IR). Lean and obese T1D adolescents have marked IR. Metformin improves surrogate markers of IR in T1D, but its effect on directly-measured IR and vascular health in T1D youth is unclear. We hypothesized that 1) T1D adolescents have impaired vascular function, and 2) metformin improves this IR and vascular dysfunction. Methods: T1D adolescents and controls underwent MRI of the ascending (AA) and descending aorta (DA) to assess pulse wave velocity (PWV), relative area change (RAC), maximal (WSSMAX) and time-averaged wall shear stress (WSSTA). T1D participants also underwent assessment of carotid intima-media thickness (cIMT) by ultrasound, brachial distensibility (BrachD) by DynaPulse, fat and lean mass by DXA, fasting labs following overnight glycemic control, and insulin sensitivity by hyperinsulinemic-euglycemic clamp (glucose infusion rate/insulin, [M/I]). T1D adolescents were randomized 1:1 to 3 months of 2000 mg metformin or placebo daily, after which baseline measures were repeated. Results: Forty-eight T1D adolescents ages 12–21 years (40% BMI ≥ 90th%ile; 56% female) and twenty-four nondiabetic controls of similar age, BMI and sex distribution were enrolled. T1D adolescents demonstrated impaired aortic health vs. controls, including elevated AA and DA PWV, reduced AA and DA RAC and elevated AA and DA WSSMAX and WSSTA. T1D adolescents in the metformin vs. placebo group had improved M/I (12.2±3.2 vs. −2.4±3.6 [mg/kg/min]/uIU/uL, p=0.005; 18.6±4.8 vs. −3.4±5.6 [mg/lean kg/min]/uIU/uL, p=0.005) and reduced weight (−0.5±0.5 vs. 1.6±0.5 kg, p=0.004), BMI (−0.2±0.15 vs. 0.4±0.15 kg/m2, p=0.005) and fat mass (−0.7±0.3 vs. 0.6±0.4 kg, p=0.01). M/I also improved in normal-weight participants (11.8±4.4 vs. −4.5±4.4 [mg/kg/min]/uIU/uL, p=0.02, 17.6±6.7 vs. −7.0±6.7 [mg/lean kg/min]/uIU/uL, p=0.02). The metformin group had reduced AA WSSMAX (−0.3±0.4 vs. 1.5±0.5 dyne/cm2, p=0.03), AA PWV, (−1.1±1.20 vs. 4.1±1.6 m/s, p=0.04) and far-wall diastolic cIMT (−0.04±0.01 vs. −0.00±0.01 mm, p=0.049) vs. placebo. Conclusions: T1D adolescents demonstrate IR and impaired vascular health vs. controls. Metformin improves IR, regardless of baseline BMI, and BMI, weight, fat mass, insulin dose, aortic and carotid health in T1D adolescents. Metformin may hold promise as a cardioprotective intervention in T1D.

Objective Increased liver fat and type 2 diabetes are prevalent in women with polycystic ovarian syndrome (PCOS) and cause excess mortality, yet little is known about their development during adolescence. Our goal was to measure hepatic steatosis and related metabolic contributors in girls with obesity, with and without PCOS. Methods Nondiabetic adolescents with obesity, 41 with PCOS (PCOS; age 15.0(13.0,16.0) years, BMI 35.2±0.61 kg/m2) and 30 without PCOS (OB; age 14.5(13.0,17.0), BMI 33.2±1.8) were studied. Visceral and liver fat were assessed with MRI. Serum measures included androgens and 16 and 18 n7 fatty acids specific to de novo lipogenesis. Adipose, hepatic and peripheral insulin sensitivity (IS) were assessed with a 4-phase hyperinsulinemic-euglycemic clamp with isotope tracers. Results 49% PCOS had hepatic steatosis vs. 14% OB (p=0.02), and PCOS had higher n7 (43±4 nmol/g vs. 29±5; p=0.02). Peripheral IS was lower in PCOS (9.4(7.2,12.3) mg/lean kg/min vs. 14.5(13.1,18.05); p<0.001) as was hepatic (p=0.006) and adipose IS (p=0.005). Percent liver fat correlated with n7 (R=0.46, p=0.02) and visceral fat (R=0.42, p<0.001), not androgens or peripheral IS. Conclusions Nearly 50% of nondiabetic girls with PCOS and obesity have hepatic steatosis, which related to visceral fat and lipogenesis, but not to IS or androgens.

Context Alterations in gut microbiota relate to the metabolic syndrome, but have not been examined in at-risk obese youth with polycystic ovary syndrome (PCOS). Objective Compare the composition and diversity of the gut microbiota and associations with metabolic and hormonal measures between 2 groups of female adolescents with equal obesity with or without PCOS. Design Prospective, case-control cross-sectional study. Setting Tertiary-care center. Participants A total of 58 obese female adolescents (n = 37 with PCOS; 16.1 ± 0.3 years of age; body mass index [BMI] 98.5th percentile) and (n = 21 without PCOS; 14.5 ± 0.4 years of age; BMI 98.7th percentile). Outcomes Bacterial diversity, percent relative abundance (%RA), and correlations with hormonal and metabolic measures. Results Participants with PCOS had decreased α-diversity compared with the non-PCOS group (Shannon diversity P = 0.045 and evenness P = 0.0052). β-diversity, reflecting overall microbial composition, differed between groups (P &lt; 0.001). PCOS had higher %RA of phyla Actinobacteria (P = 0.027), lower Bacteroidetes (P = 0.004), and similar Firmicutes and Proteobacteria. PCOS had lower %RA of families Bacteroidaceae (P &lt; 0.001) and Porphyromonadaceae (P = 0.024) and higher Streptococcaceae (P = 0.047). Lower bacterial α-diversity was strongly associated with higher testosterone concentrations. Several individual taxa correlated with testosterone and metabolic measures within PCOS and across the entire cohort. Receiver operative curve analysis showed 6 taxa for which the %RA related to PCOS status and lower Bacteroidaceae conferred a 4.4-fold likelihood ratio for PCOS. Conclusion Alterations in the gut microbiota exist in obese adolescents with PCOS versus obese adolescents without PCOS and these changes relate to markers of metabolic disease and testosterone. Further work is needed to determine if microbiota changes are reflective of, or influencing, hormonal metabolism.

Insulin resistance (IR) increases cardiovascular morbidity and is associated with mitochondrial dysfunction. IR is now recognized to be present in type 1 diabetes; however, its relationship with mitochondrial function is unknown. We determined the relationship between IR and muscle mitochondrial function in type 1 diabetes using the hyperinsulinemic-euglycemic clamp and 31P-MRS before, during, and after near-maximal isometric calf exercise. Volunteers included 21 nonobese adolescents with type 1 diabetes and 17 nondiabetic control subjects with similar age, sex, BMI, Tanner stage, and activity levels. We found that youths with type 1 diabetes were more insulin resistant (median glucose infusion rate 10.1 vs. 18.9 mg/kglean/min; P < 0.0001) and had a longer time constant of the curve of ADP conversion to ATP (23.4 ± 5.3 vs. 18.8 ± 3.9 s, P < 0.001) and a lower rate of oxidative phosphorylation (median 0.09 vs. 0.21 mmol/L/s, P < 0.001). The ADP time constant (β = −0.36, P = 0.026) and oxidative phosphorylation (β = 0.02, P < 0.038) were related to IR but not HbA1c. Normal-weight youths with type 1 diabetes demonstrated slowed postexercise ATP resynthesis and were more insulin resistant than control subjects. The correlation between skeletal muscle mitochondrial dysfunction in type 1 diabetes and IR suggests a relationship between mitochondrial dysfunction and IR in type 1 diabetes.

Objective:Obese girls with polycystic ovarian syndrome (PCOS) have decreased insulin sensitivity (IS), muscle mitochondrial dysfunction and increased liver fat, which may contribute to their increased risk for type 2 diabetes. Less is known regarding normal-weight girls with PCOS.Methods:Normal-weight girls with PCOS [n =18, age 15.9 ± 1.8 years, body mass index (BMI) percentile 68 ± 18] and normal-weight controls (NWC; n = 20; age 15.0 ± 2.1 years, BMI percentile 60 ± 21) were studied. Tissue-specific IS was assessed with a four-phase hyperinsulinemic-euglycemic clamp with isotope tracers and a 2-hour oral glucose tolerance test (OGTT). Hepatic fat was determined using magnetic resonance imaging. Postexercise muscle mitochondrial function was assessed with 31P MR spectroscopy.Results:Both groups had similar demographics, anthropomorphics, physical attributes, habitual physical activity levels and fasting laboratory values, except for increased total testosterone and DHEAS in PCOS. Clamp-assessed peripheral IS was lower in PCOS (10.4 ± 2.4 mg/kg/min vs 12.7 ± 2.1; P = 0.024). The 120-minute OGTT insulin and glucose concentrations were higher in PCOS (114 IU/mL ± 26 vs 41 ± 25, P = <0.001 and 119 ± 22 mg/dL vs 85 ± 23, P = 0.01, respectively). Muscle mitochondrial ADP and phosphocreatine time constants were slower in PCOS. Despite a higher percentage liver fat in PCOS, hepatic IS was similar between groups, as was adipose IS.Conclusions:Normal-weight girls with PCOS have decreased peripheral IS and muscle mitochondrial dysfunction, abnormal glucose disposal, relative postprandial hyperinsulinemia, and increased hepatic fat compared to NWC. Despite a normal BMI, multiple aspects of metabolism appear altered in normal-weight girls with PCOS.

Type 2 diabetes (T2DM), historically an adult disease, is now increasingly prevalent in obese youth. Poor diet and increased sedentary behavior contribute to the increasing rates of obesity in youth, yet not all obese children develop T2DM. In general, T2DM is characterized by both insulin resistance (IR) and pancreatic beta-cell insufficiency. In children, IR is related to elevated body mass index (BMI) and pubertal hormones, along with abnormal fat partitioning, elevated free fatty acids, inflammation, and/or mitochondrial dysfunction. Hyperglycemia and T2DM develop when the pancreas cannot match the increased insulin demands resulting from IR. Unique to youth, IR varies with stage of pubertal development, and some children may have resolution of hyperglycemia post-puberty once the IR of puberty resolves. Further understanding of IR, the progression to T2DM in youth, and later outcomes as adults will help direct future therapies and interventions for youth at risk.