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.
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.
Adolescents with T1D have adipose, hepatic and peripheral IR. This IR occurs regardless of obesity and metabolic syndrome features. Youth with T1D may benefit from interventions directed at improving IR in these tissues, and this area requires further research.
Background--Myocardial mechanics are altered in adults with obesity and type 2 diabetes (T2D); insulin resistance and adipokines have been implicated as important risk factors for cardiovascular disease, but these relationships are poorly described in adolescents. We hypothesized that obese adolescents and adolescents with T2D would have abnormal cardiac function compared to lean adolescents. In addition, we hypothesized that insulin sensitivity (IS), adiposity, and adipokines would be associated with altered cardiac strain and cardiopulmonary fitness in adolescents with T2D.
Aims Insulin resistance (IR) correlates with mitochondrial dysfunction, free fatty acids (FFAs), and intramyocellular lipid (IMCL) in adults with type 2 diabetes (T2D). We hypothesized that muscle IR would relate to similar factors in T2D youth. Methods Participants included 17 youth with T2D, 23 normal weight controls (LCs), and 26 obese controls (OBs) of similar pubertal stage and activity level. Results T2D and OB groups were of similar BMI. T2D youth were significantly more IR and had higher calf IMCL and serum FFA concentrations during hyperinsulinemia. ADP time constant (ADPTC), a blood-flow dependent mitochondrial function measure, was slowed and oxidative phosphorylation rates lower in T2D. In multiple linear regression of the entire cohort, lack of FFA suppression and longer ADPTC, but not IMCL or HbA1c, were independently associated with IR. Conclusion We found that elevated FFAs and mitochondrial dysfunction are early abnormalities in relatively well-controlled youth with T2D. Further, post-exercise oxidative metabolism appears affected by reduced blood flow, and is not solely an inherent mitochondrial defect. Thus, lowering FFAs and improving mitochondrial function and blood flow may be potential treatment targets in youth with T2D.
Cree-Green M, Newcomer BR, Coe G, Newnes L, Baumgartner A, Brown MS, Pyle L, Reusch JE, Nadeau KJ. Peripheral insulin resistance in obese girls with hyperandrogenism is related to oxidative phosphorylation and elevated serum free fatty acids. 31 phosphorus MR spectroscopy before, during, and after near-maximal isometric calf exercise, and peripheral IR was assessed with an 80 mU·m Ϫ2 ·min Ϫ1 hyperinsulinemic euglycemic clamp. Girls with HAS had higher androgens [free androgen index 7.9(6.6,15.5) vs. 3.5(3.0,4.0), P Ͻ 0.01] and more IR [glucose infusion rate 9.4(7.0, 12,2) vs. 14.5(13.2,15.8) mg·kg lean Ϫ1 ·min Ϫ1 , P Ͻ 0.01]. HAS girls also had increased markers of inflammation including CRP, platelets, and white blood cell count and higher serum free fatty acids during hyperinsulinemia. Mitochondrial oxidative phosphorylation was lower in HAS [0.11(0.06,0.19) vs. 0.18(0.12,0.23) mmol/s, P Ͻ 0.05], although other spectroscopy markers of mitochondrial function were similar between groups. In multivariate analysis of the entire cohort, IR related to androgens, oxidative phosphorylation, and free fatty acid concentrations during hyperinsulinemia. These relationships were present in just the HAS cohort as well. Obese girls with HAS have significant peripheral IR, which is related to elevated androgens and free fatty acids and decreased mitochondrial oxidative phosphorylation. These may provide future options as targets for therapeutic intervention.hyperandrogenism; insulin resistance; mitochondria; obesity; hyperandrogenic syndrome HYPERANDROGENIC SYNDROME (HAS), also known as polycystic ovarian syndrome (PCOS), affects at least 10 -15% of the female population in the United States, with a recent increase in prevalence associated with rising obesity rates (32). Women with HAS have a three-to fourfold increased risk of developing type 2 diabetes (T2D) compared with BMI-matched controls (37, 58). This increased risk is thought to be secondary to long-standing insulin resistance (IR) (37). There is also evidence of IR in youth with HAS (2). Similar to findings in T2D, peripheral IR as assessed with a hyperinsulinemic euglycemic clamp has been well documented in adults with HAS (7, 15), with similar but fewer data in youth (2). However, the mechanism of IR in HAS remains uncertain, and as a result the best treatments for HAS are also unclear.A leading theory explaining IR in T2D includes defects in mitochondrial function in combination with excess serum free fatty acids (FFA), which can cause alterations in intracellular insulin signaling (52). Other potential mechanisms involve altered fat metabolism and inflammation, which have been documented in T2D and HAS but have not been examined in adolescents with HAS (14,25,29,33,54). However, data examining the role of mitochondria in IR in HAS are limited and conflicting. Muscle mitochondrial oxidation gene expression for oxidative enzymes such as citrate synthase, or -hydroxyacyl-CoA dehydrogenase were similar between women with and without HAS despite worse IR in the wom...
Objective Diabetic cardiomyopathy is a major cause of morbidity, but limited data are available on early cardiac abnormalities in type 1 diabetes (T1D). We investigated differences in myocardial strain in adolescents with and without T1D. We hypothesized that adolescents with T1D would have worse strain than their normoglycemic peers, which boys would have worse strain than girls, and that strain would correlate with glycemic control and adipokines. Methods We performed fasting laboratory measures and echocardiograms with speckle tracking to evaluate traditional echocardiographic measures in addition to longitudinal (LS) and circumferential (CS) strain, and in adolescents (15±2 years) with (19 boys; 22 girls) and without (16 boys; 32 girls) type 1 diabetes. Results Compared to controls, adolescents with type 1 diabetes had significantly lower CS (−20.9 vs. −22.7%, p=0.02), but not LS (p=0.83). Boys with T1D had significantly lower LS than girls with T1D (−17.5 vs. −19.7%, p=0.047), adjusted for Tanner stage. The significant sex differences observed in indexed left ventricular mass, left end-diastolic volume, diastolic septal and posterior wall thickness in our controls were lacking in adolescents with T1D. Conclusions Our observations suggest that youth with T1D have worse myocardial strain than normoglycemic peers. In addition, the relatively favorable cardiac profile observed in girls vs. boys in the control group, was attenuated in T1D. These early cardiovascular changes in youth with T1D are concerning and warrant longitudinal and mechanistic studies.
To evaluate the contemporary prevalence of diabetic peripheral neuropathy (DPN) in participants with type 1 diabetes in the T1D Exchange Clinic Registry throughout the U.S. RESEARCH DESIGN AND METHODSDPN was assessed with the Michigan Neuropathy Screening Instrument Questionnaire (MNSIQ) in adults with ‡5 years of type 1 diabetes duration. A score of ‡4 defined DPN. Associations of demographic, clinical, and laboratory factors with DPN were assessed. RESULTSAmong 5,936 T1D Exchange participants (mean 6 SD age 39 6 18 years, median type 1 diabetes duration 18 years [interquartile range 11, 31], 55% female, 88% non-Hispanic white, mean glycated hemoglobin [HbA 1c ] 8.1 6 1.6% [65.3 6 17.5 mmol/mol]), DPN prevalence was 11%. Compared with those without DPN, DPN participants were older, had higher HbA 1c , had longer duration of diabetes, were more likely to be female, and were less likely to have a college education and private insurance (all P < 0.001). DPN participants also were more likely to have cardiovascular disease (CVD) (P < 0.001), worse CVD risk factors of smoking (P 5 0.008), hypertriglyceridemia (P 5 0.002), higher BMI (P 5 0.009), retinopathy (P 5 0.004), reduced estimated glomerular filtration rate (P 5 0.02), and Charcot neuroarthropathy (P 5 0.002). There were no differences in insulin pump or continuous glucose monitor use, although DPN participants were more likely to have had severe hypoglycemia (P 5 0.04) and/or diabetic ketoacidosis (P < 0.001) in the past 3 months. CONCLUSIONSThe prevalence of DPN in this national cohort with type 1 diabetes is lower than in prior published reports but is reflective of current clinical care practices. These data also highlight that nonglycemic risk factors, such as CVD risk factors, severe hypoglycemia, diabetic ketoacidosis, and lower socioeconomic status, may also play a role in DPN development.Diabetic neuropathy is a prevalent complication in patients with diabetes and a major cause of morbidity and mortality (1). Among the various forms of diabetic neuropathy, distal symmetric polyneuropathy (DPN) and diabetic autonomic neuropathies are by far the most studied (1).
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