The association of sleep disturbances with glycemia and obesity in youth at risk for or with recently diagnosed type 2 diabetes.

OBJECTIVE: Poor sleep may increase obesity and type 2 diabetes (T2D) risk in youth. We explored whether subjective sleep duration, sleep quality, or risk for obstructive sleep apnea (OSA) are associated with glycemia, body mass index (BMI), or blood pressure (BP) in overweight/obese youth. METHODS: Two-hundred and fourteen overweight/obese youth of 10 to 19 years of age at risk for or recently diagnosed with T2D who were screened for the Restoring Insulin Secretion (RISE) Study had a 2-hour oral glucose tolerance test (OGTT) and completed a Cleveland Adolescent Sleepiness questionnaire and a Sleep Disturbances Scale questionnaire. Independent associations between sleep variables and measures of glycemia, BMI, and BP were evaluated with regression models. RESULTS: The multiethnic cohort was 67% female, 14.1 ± 2.1 years, and BMI 35.9 ± 6.5 kg/m2 . Habitual sleep duration <8 hours was reported in 74%. Daytime sleepiness was reported in 51%, poor sleep quality in 26%, and 30% had high obstructive sleep apnea (OSA) risk. Daytime sleepiness was associated with higher HbA1c (0.2%, P = .02) and 2-hour glucose (13.6 mg/dL, P < .05). Sleep duration, sleep quality, and OSA risk were not associated with the evaluated outcomes. Poor sleep quality and OSA risk were associated with higher BMI (2.9 kg/m2 , P = .004 and 2.83 kg/m2 , P < .003, respectively). CONCLUSIONS: In overweight/obese youth with or at risk for T2D, daytime sleepiness was associated with higher HbA1c. In addition, poor sleep quality and OSA risk were associated with higher BMI. These findings support intervention studies aimed at improving sleep quality in obese youth.

The 2018 World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) score and diabetes risk in the Diabetes Prevention Program Outcomes Study (DPPOS).

BACKGROUND: The 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) 3rd expert report highlights up-to-date Cancer Prevention Recommendations that may reduce burdens of many chronic diseases, including diabetes. This study examined if following a lifestyle that aligns with the recommendations - assessed via the 2018 WCRF/AICR Score - was associated with lower risk of type 2 diabetes in high-risk adults participating in the Diabetes Prevention Program Outcomes Study (DPPOS). METHODS: The Diabetes Prevention Program (DPP) randomized adults at high risk for diabetes to receive a lifestyle intervention (ILS), metformin (MET) or a placebo (PLB) (mean: 3.2 years), with additional follow-up in DPPOS for 11 years (mean: 15 years total). 2018 WCRF/AICR Scores included seven components: body weight, physical activity, plant-based foods, fast foods, red and processed meat, sugar-sweetened beverages, and alcohol; the optional breastfeeding component was excluded. Scores ranged 0-7 points (with greater scores indicating greater alignment with the recommendations) and were estimated at years 0, 1, 5, 6, 9, and 15 (N=3,147). Fasting glucose and HbA1c were measured every six months and oral glucose tolerance tests were performed annually. Adjusted Cox proportional hazard ratios (HRs) and 95% confidence intervals (CIs) were used to examine the association of both Score changes from years 0-1 and time-dependent Score changes on diabetes risk through DPP and year 15. RESULTS: Scores improved within all groups over 15 years (p<0.001); ILS Scores improved more than MET or PLB Scores after 1 year (p<0.001). For every 1-unit improvement from years 0-1, there was a 31% and 15% lower diabetes risk in ILS (95% CI: 0.56-0.84) and PLB (95% CI: 0.72-0.97) through DPP, and no significant association in MET. Associations were greatest among American Indian participants, followed by non-Hispanic White and Hispanic participants. Score changes from years 0-1 and time-dependent Score changes in ILS and PLB remained associated with lower risk through year 15. CONCLUSIONS: Score improvements were associated with long-term, lower diabetes risk among high-risk adults randomized to ILS and PLB, but not MET. Future research should explore impact of the Score on cancer risk. TRIAL REGISTRATION: Diabetes Prevention Program: NCT00004992 ; Diabetes Prevention Program Outcomes Study: NCT00038727.

Obstructive Sleep Apnea, Glucose Tolerance, and ß-Cell Function in Adults With Prediabetes or Untreated Type 2 Diabetes in the Restoring Insulin Secretion (RISE) Study.

OBJECTIVE: Obstructive sleep apnea (OSA) is associated with insulin resistance and has been described as a risk factor for type 2 diabetes. Whether OSA adversely impacts pancreatic islet ß-cell function remains unclear. We aimed to investigate the association of OSA and short sleep duration with ß-cell function in overweight/obese adults with prediabetes or recently diagnosed, treatment-naive type 2 diabetes. RESEARCH DESIGN AND METHODS: Two hundred twenty-one adults (57.5% men, age 54.5 ± 8.7 years, BMI 35.1 ± 5.5 kg/m2) completed 1 week of wrist actigraphy and 1 night of polysomnography before undergoing a 3-h oral glucose tolerance test (OGTT) and a two-step hyperglycemic clamp. Associations of measures of OSA and actigraphy-derived sleep duration with HbA1c, OGTT-derived outcomes, and clamp-derived outcomes were evaluated with adjusted regression models. RESULTS: Mean ± SD objective sleep duration by actigraphy was 6.6 ± 1.0 h/night. OSA, defined as an apnea-hypopnea index (AHI) of five or more events per hour, was present in 89% of the participants (20% mild, 28% moderate, 41% severe). Higher AHI was associated with higher HbA1c (P = 0.007). However, OSA severity, measured either by AHI as a continuous variable or by categories of OSA severity, and sleep duration (continuous or <6 vs. ≥6 h) were not associated with fasting glucose, 2-h glucose, insulin sensitivity, or ß-cell responses. CONCLUSIONS: In this baseline cross-sectional analysis of the RISE clinical trial of adults with prediabetes or recently diagnosed, untreated type 2 diabetes, the prevalence of OSA was high. Although some measures of OSA severity were associated with HbA1c, OSA severity and sleep duration were not associated with measures of insulin sensitivity or ß-cell responses.

Diet quality, weight loss, and diabetes incidence in the Diabetes Prevention Program (DPP).

BACKGROUND: We evaluated whether diet quality is a predictor of weight loss and reduced diabetes risk, independent of caloric intake in the Diabetes Prevention Program (DPP) cohort, a randomized clinical trial of adults at risk for diabetes. METHODS: This secondary analysis included 2914 participants with available data (964 intensive lifestyle (ILS), 977 metformin, 973 placebo). Dietary intake was assessed using a 117-item food frequency questionnaire. Diet quality was quantified using the Alternative Healthy Eating Index 2010 (AHEI). AHEI ranges from 0 to 110, with higher scores corresponding to higher quality diets. ILS participants had greater improvement (p < 0.001) in AHEI over 1-year (4.2 ± 9.0) compared to metformin (1.2 ± 8.5) and placebo (1.4 ± 8.4). We examined the association between AHEI change and weight change from baseline to 1-year using linear regression, and that between 1-year AHEI change and incident diabetes, using hazard models over an average 3 years follow-up. Models were evaluated within treatment group and adjusted for relevant characteristics including caloric intake, physical activity, BMI and AHEI. Models testing incident diabetes were further adjusted for baseline fasting and 2 h glucose. RESULTS: An increase in AHEI score was associated with weight loss in ILS [ß per 10-point increase (SE) -1.2 kg (0.3, p < 0.001)], metformin [- 0. 90 kg (0.2, p < 0.001)] and placebo [- 0.55 kg (0.2, p = 0.01)]. However, AHEI change was not associated with incident diabetes in any group before or after adjustment for weight change. CONCLUSIONS: Controlling for weight, diet quality was not associated with diabetes incidence but helps achieve weight loss, an important factor in diabetes prevention.

Association of Habitual Daily Physical Activity With Glucose Tolerance and ß-Cell Function in Adults With Impaired Glucose Tolerance or Recently Diagnosed Type 2 Diabetes From the Restoring Insulin Secretion (RISE) Study.

OBJECTIVE: We examined the relationship between habitual daily physical activity and measures of glucose tolerance, insulin sensitivity, and ß-cell responses in adults with impaired glucose tolerance (IGT) or drug-naive, recently diagnosed type 2 diabetes. RESEARCH DESIGN AND METHODS: Participants included 230 adults (mean ± SD age 54.5 ± 8.5 years, BMI 35 ± 5.5 kg/m2; 42.6% women) who underwent a 3-h oral glucose tolerance test (OGTT) and hyperglycemic clamp. Wrist accelerometers worn for 7 consecutive days measured total physical activity counts (TAC) (daily mean 233,460 [∼50th percentile for age]). We evaluated whether TAC was associated with fasting plasma glucose, OGTT 2-h plasma glucose or glucose incremental area under the curve (G-iAUC), hyperglycemic clamp measures of insulin sensitivity (steady-state glucose infusion rate/insulin [M/I]) and ß-cell responses (acute C-peptide response to glucose, steady-state C-peptide, and maximal ß-cell response), and OGTT C-peptide index (ΔC-peptide0-30/Δglucose0-30). RESULTS: After adjustments for confounders, there was no association of TAC with fasting plasma glucose, 2-h glucose, or G-iAUC. Higher TAC was associated with higher insulin sensitivity (M/I). After adjusting for M/I, higher TAC was not associated with measures of ß-cell response. CONCLUSIONS: In adults with IGT or drug-naive, recently diagnosed type 2 diabetes, higher levels of habitual physical activity are associated with higher insulin sensitivity. Further studies are needed to understand why higher levels of physical activity are not associated with better ß-cell response.

Association of Self-Reported Sleep and Circadian Measures With Glycemia in Adults With Prediabetes or Recently Diagnosed Untreated Type 2 Diabetes.

OBJECTIVE: Sleep disturbances and circadian misalignment (social jet lag, late chronotype, or shift work) have been associated with worse glycemic control in type 2 diabetes (T2D). Whether these findings apply to adults with prediabetes is yet unexplored. We hypothesized that self-reported short sleep, poor sleep quality, and/or circadian misalignment are associated with higher glycemia, BMI, and blood pressure (BP) in adults with prediabetes or recently diagnosed, untreated T2D. RESEARCH DESIGN AND METHODS: Our cohort included 962 overweight/obese adults ages 20-65 years with prediabetes or recently diagnosed, untreated T2D who completed a 2-h oral glucose tolerance test and validated sleep questionnaires. Independent associations of sleep and circadian variables with glycemia, BMI, and BP were evaluated with regression models. RESULTS: The multiethnic cohort was 55% men, with mean ± SD age 52.2 ± 9.5 years and BMI 34.7 ± 5.5 kg/m2. Mean sleep duration was 6.6 ± 1.3 h. Poor sleep quality was reported by 54% and high risk for obstructive sleep apnea by 64%. HbA1c was significantly higher in those reporting <5 or >8 h sleep per night. Sleep duration >8 h was also associated with higher fasting glucose and <6 h with higher BMI. Shift work was also associated with higher BMI. Social jet lag and delayed chronotype were associated with higher BP. CONCLUSIONS: In our cohort, self-reported short and long sleep were both associated with adverse measures of glycemia, and short sleep and shift work were associated with higher BMI. Further research using objective measures of sleep is needed to better delineate the relationship between sleep and glycemia in adults with prediabetes or T2D.

An estrogen receptor-alpha knock-in mutation provides evidence of ligand-independent signaling and allows modulation of ligand-induced pathways in vivo.

Estrogen-nonresponsive estrogen receptor-alpha (ERalpha) knock-in (ENERKI) mice were generated to distinguish between ligand-induced and ligand-independent ER-alpha actions in vivo. These mice have a mutation [glycine 525 to leucine (G525L)] in the ligand-binding domain of ERalpha, which significantly reduces ERalpha interaction with and response to endogenous estrogens, whereas not affecting growth factor activation of ligand-independent pathways. ENERKI mice had hypoplastic uterine tissues and rudimentary mammary gland ductal trees. Females were infertile due to anovulation, and their ovaries contained hemorrhagic cystic follicles because of chronically elevated levels of LH. The ENERKI phenotype confirmed that ligand-induced activation of ERalpha is crucial in the female reproductive tract and mammary gland development. Growth factor treatments induced uterine epithelial proliferation in ovariectomized ENERKI females, directly demonstrating that ERalpha ligand-independent pathways were active. In addition, the synthetic ERalpha selective agonist propyl pyrazole triol (PPT) and ER agonist diethylstilbestrol (DES) were still able to activate ligand-induced G525L ERalpha pathways in vitro. PPT treatments initiated at puberty stimulated ENERKI uterine development, whereas neonatal treatments were needed to restore mammary gland ductal elongation, indicating that neonatal ligand-induced ERalpha activation may prime mammary ducts to become more responsive to estrogens in adult tissues. This is a useful model for in vivo evaluation of ligand-induced ERalpha pathways and temporal patterns of response. DES did not stimulate an ENERKI uterotrophic response. Because ERbeta may modulate ERalpha activation and have an antiproliferative function in the uterus, we hypothesize that ENERKI animals were particularly sensitive to DES-induced inhibition of ERalpha due to up-regulated uterine ERbeta levels.

Sex Differences in the Impact of Obstructive Sleep Apnea on Glucose Metabolism.

Objectives: Obstructive sleep apnea (OSA) is more prevalent in men and is an independent risk factor for type 2 diabetes. We aimed to determine if there are sex differences in the impact of OSA on glucose metabolism in nondiabetic overweight and obese adults. Methods: One hundred and forty-five men and women (age 33.4 ± 0.6, BMI 37.2 ± 0.7, 70.3% blacks) from the community underwent in-laboratory polysomnography. Severity of OSA was assessed by the apnea-hypopnea index (AHI). Glucose tolerance was assessed using fasting glucose, 1-h glucose, 2-h glucose and the area under the curve (AUC) during the 2-h oral glucose tolerance test (OGTT). Fasting insulin resistance was assessed by HOMA-IR, and insulin sensitivity during the OGTT was assessed by the Matsuda Index. Pancreatic beta-cell function was assessed by fasting HOMA-%B and by AUCinsulin/glucose, insulinogenic index, and oral disposition index (DIoral) during the OGTT. All comparisons were adjusted for age, BMI, race and severity of OSA. Results: There were no significant demographic differences between men and women without OSA. Men and women with OSA were similar in age, BMI, and severity of OSA, but there were more black women with OSA. Compared to women with OSA, men with OSA had significantly higher fasting glucose, 1-h glucose levels, AUCglucose, and AUC for insulin secretion rate (AUCISR) but similar 2-h glucose levels. These differences persisted in adjusted analyses. Men with OSA secreted significantly more insulin than women with OSA in order to achieve similar glucose levels. Men with OSA had significantly worse beta cell function as measured by the DIoral than women with OSA. In contrast, there were no significant sex differences in measures of glucose tolerance and beta-cell function in participants without OSA. Conclusion: Men with OSA secreted more insulin compared to women with OSA in order to maintain glucose homeostasis. The adverse impact of OSA on beta-cell responsiveness was larger in men, which may result in an overall greater risk of type 2 diabetes compared to women.

Determinants of Slow-Wave Activity in Overweight and Obese Adults: Roles of Sex, Obstructive Sleep Apnea and Testosterone Levels.

Background: Slow-wave activity (SWA) in non-rapid eye movement (NREM) sleep, obtained by spectral analysis of the electroencephalogram, is a marker of the depth or intensity of NREM sleep. Higher levels of SWA are associated with lower arousability during NREM sleep and protect against sleep fragmentation. Multiple studies have documented that SWA levels are higher in lean women, compared to age-matched lean men, but whether these differences persist in obese subjects is unclear. Obstructive sleep apnea (OSA), a condition associated with obesity, is more prevalent in men than in women. Sex differences in SWA could therefore be one of the factors predisposing men to OSA. Furthermore, we hypothesized that higher levels of testosterone may be associated with lower levels of SWA. Objective: The aim of the current study was to identify sex differences in the determinants of SWA in young and middle-aged overweight and obese adults. Methods: We enrolled 101 overweight and obese but otherwise healthy participants from the community (44 men, 57 women) in this cross-sectional study. Participants underwent an overnight in-laboratory polysomnogram. The recordings were submitted to sleep staging and spectral analysis. Sex differences and the potential contribution of testosterone levels were evaluated after adjusting for age, body mass index and race/ethnicity. Results: OSA was present in 66% of men and in 44% of women. After adjustment for differences in age, race/ethnicity and BMI, the odds ratio for OSA in men vs. women was 3.17 (95% CI 1.14-9.43, p = 0.027). There was a graded inverse relationship between the apnea-hypopnea index (AHI) and SWA in men (ß = -0.21, p = 0.018) but not in women (ß = 0.10, p = 0.207). In a multivariate regression model, higher testosterone levels were independently associated with lower SWA in men after controlling for age, race/ethnicity and apnea-hypopnea index (ß = -0.56, p = 0.025). Conclusion: Increasing severity of OSA was associated with significant decrease in sleep intensity in men but not in women. Higher testosterone levels were associated with lower sleep intensity in men. Men with higher testosterone levels may therefore have lower arousal thresholds and higher ventilatory instability in NREM sleep, and be at greater risk of OSA.

Uncoupling of 3T3-L1 gene expression from lipid accumulation during adipogenesis.

Adipocyte differentiation comprises altered gene expression and increased triglyceride storage. To investigate the interdependency of these two events, 3T3-L1 cells were differentiated in the presence of glucose or pyruvate. All adipocytic proteins examined were similarly increased between the two conditions. In contrast, 3T3-L1 adipocytes differentiated with glucose exhibited significant lipid accumulation, which was largely suppressed in the presence of pyruvate. Subsequent addition of glucose to the latter cells restored lipid accumulation and acute rates of insulin-stimulated lipogenesis. These data indicate that extracellular energy is required for induction of adipocytic proteins, while only glucose sustained the parallel increase in triglyceride storage.

Generation of embryonic stem cells from mouse insulin I promoter-green fluorescent protein transgenic mice and characterization in a teratoma model.

Insulin-secreting pancreatic beta cells play a key role in the pathogenesis of diabetes mellitus. Potential new treatments for this disease include cell-replacement therapies using embryonic stem cells (ESCs). We have generated ESCs from a transgenic mouse model, mouse insulin 1 promoter (MIP) green fluorescent protein (GFP) mice, in which embryonic and adult beta cells are genetically tagged with GFP. The aim of the present study is to examine the differentiation potential of MIP-GFP ESCs in the microenvironment of the kidney capsule. The ESCs grew rapidly and formed a teratoma with GFP-expressing beta-like cells present in clusters that formed a cord-like structure similar to what is seen in the embryonic pancreas. These structures also included glucagon-expressing alpha cells and amylase-expressing acinar cells. Electron microscopic analysis showed insulin-like granules in columnar epithelium with microvilli adjacent to exocrine-like granule-containing cells. The MIP-GFP ESCs should be a useful research tool to study the differentiation capacity of ESCs toward pancreatic lineages.

Differential modulation of 3T3-L1 adipogenesis mediated by 11beta-hydroxysteroid dehydrogenase-1 levels.

The localized activation of circulating glucocorticoids in vivo by the enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) plays a critical role in the development of the metabolic syndrome. However, the precise contribution of 11beta-HSD1 in the initiation of adipogenesis by inactive glucocorticoids is not fully understood. 3T3-L1 fibroblasts can be terminally differentiated to mature adipocytes in a glucocorticoid-dependent manner. Both inactive rodent dehydrocorticosterone and human cortisone were able to substitute for the synthetic glucocorticoid dexamethasone in 3T3-L1 adipogenesis, suggesting a potential role for 11beta-HSD1 in these effects. Differentiation of 3T3-L1 cells caused a strong increase in 11beta-HSD1 protein levels, which occurred late in the differentiation protocol. Reduction of 11beta-HSD1 activity in 3T3-L1 fibroblasts, achieved by pharmacological inhibition or adenovirally mediated delivery of short hairpin RNA constructs, specifically blocked the ability of inactive glucocorticoids to drive 3T3-L1 differentiation. However, even modest increases in exogenous 11beta-HSD1 expression in 3T3-L1 fibroblasts, to levels comparable with endogenous 11beta-HSD1 in differentiated 3T3-L1 adipocytes, were sufficient to block adipogenesis. Luciferase reporter assays indicated that overexpressed 11beta-HSD1 was catalyzing the inactivating dehydrogenase reaction, because the ability of both active and inactive glucocorticoids to activate the glucocorticoid receptor were largely suppressed. These results suggest that the temporal regulation of 11beta-HSD1 expression is tightly controlled in 3T3-L1 cells, so as to mediate the initiation of differentiation by inactive glucocorticoids and also to prevent the inhibitory activity of prematurely expressed 11beta-HSD1 during adipogenesis.

The nuclear receptor corepressors NCoR and SMRT decrease peroxisome proliferator-activated receptor gamma transcriptional activity and repress 3T3-L1 adipogenesis.

The peroxisome proliferator-activated receptor gamma (PPARgamma) is a central regulator of adipogenesis and recruits coactivator proteins in response to ligand. However, the role of another class of nuclear cofactors, the nuclear receptor corepressors, in modulating PPARgamma transcriptional activity is less clear. Such corepressors include the nuclear receptor corepressor (NCoR) and the silencing mediator of retinoid and thyroid hormone receptors (SMRT). Our data suggest that PPARgamma recruits SMRT and NCoR in the absence of ligand and that these corepressors are capable of down-regulating PPARgamma-mediated transcriptional activity. The addition of the PPARgamma ligand pioglitazone results in dissociation of the PPARgamma-corepressor complex. To define the role of SMRT and NCoR in PPARgamma action, 3T3-L1 cells deficient in SMRT or NCoR were generated by RNA interference. When these cells are exposed to differentiation media, they exhibit increased expression of adipocyte-specific genes and increased production of lipid droplets, as compared with control cells. These data suggest that the nuclear receptor corepressors decrease PPARgamma transcriptional activity and repress the adipogenic program in 3T3-L1 cells.

An intact DNA-binding domain is not required for peroxisome proliferator-activated receptor gamma (PPARgamma) binding and activation on some PPAR response elements.

Peroxisome proliferator-activated receptor gamma (PPARgamma) interacts with retinoid X receptor (RXR) on PPAR response elements (PPREs) to regulate transcription of PPAR-responsive genes. To investigate the binding of PPARgamma and RXR to PPREs, three mutations were constructed in the DNA-binding domains of PPARgamma; two of the mutants maintained the structure of zinc finger I (PPARgamma-GS and PPARgamma-AA), and a third mutation disrupted the protein structure of zinc finger I (PPARgamma-CS). Results indicated that the mutations of PPARgamma that maintained intact zinc fingers were capable of binding to a variety of PPREs in the presence of RXR and could activate transcription on several PPREs. In parallel, a mutation was created in the DNA-binding domain of RXRalpha that maintained the structure of the zinc fingers (RXR-GS) but did not bind DNA and was transcriptionally inactive. Examination of the 3' half-site of several PPREs revealed that variations from the consensus sequence reduced or abolished transcriptional activity, but conversion to consensus improved transcriptional activity with PPARgamma-GS and PPARgamma-AA. Examination of the 5' half-site indicated that the upstream three nucleotides were more important for transcriptional activity than the downstream three nucleotides. Our data demonstrated that stringent binding of RXR to the 3' half-site of a PPRE is more influential on the binding of the PPARgamma/RXR heterodimer than the ability of PPARgamma to bind DNA. Thus, unlike RXR, PPARgamma exhibits promiscuity in binding on a PPRE, suggesting that the definition of a PPRE for PPARgamma may need to be expanded.