Measuring In Vivo Adipose Tissue Kinetics in Humans Using the Deuterium (2H)-Labeling Approach.

White adipose tissue is a highly plastic organ that is necessary to maintain whole-body energy homeostasis. The adipose tissue mass and changes in the fat mass or distribution are regulated by changes in the synthesis and breakdown (i.e., turnover) of adipose cells and triacylglycerols. Evidence suggests that the manner and magnitude of subcutaneous adipose tissue expansion (i.e., hypertrophy vs. hyperplasia) and turnover can influence metabolic health, as adipogenesis has been implicated in the pathogenesis of obesity and related diseases. Despite the potential role of adipose turnover in human health, there is a lack of knowledge about the in vivo kinetics of adipose cells. This is due, in part, to the slow turnover rate of the cells in adipose tissue and the practical complexity of directly labeling their metabolic precursors in vivo. Herein, we describe methods to measure in vivo adipose kinetics and turnover rates in humans through the consumption of deuterium (2H)-labeled water. The incorporation of 2H into the deoxyribonucleotide moieties of DNA in pre-adipocytes and adipocytes provides an accurate measure of cell formation and death (adipose turnover). Overall, this is an innovative approach to measuring in vivo adipose kinetics and represents a substantive departure from other in vitro assessments.

Adipose tissue expansion in obesity, health, and disease.

White adipose tissue (WAT) expands under physiological conditions via an increase in adipocyte size (hypertrophy) and/or number (hyperplasia; adipogenesis), and the ability of WAT to expand to accommodate energy demands is a significant determinant of metabolic health status. Obesity is associated with impaired WAT expansion and remodeling, which results in the deposition of lipids to other non-adipose organs, leading to metabolic derangements. Although increased hyperplasia has been implicated as a cornerstone in promoting healthy WAT expansion, recent developments suggest that the role of adipogenesis as a contributing factor in the transition from impaired subcutaneous WAT expansion to impaired metabolic health remains up for debate. This mini-review will summarize recent developments and highlight emerging concepts on the features of WAT expansion and turnover, and the significance in obesity, health, and disease.

A higher proportion of small adipocytes is associated with increased visceral and ectopic lipid accumulation during weight gain in response to overfeeding in men.

BACKGROUND: Adipose tissue (AT) expansion occurs by hypertrophy (increase in size) and hyperplasia (increase in number) of adipocytes. The AT expandability hypothesis postulates that impaired subcutaneous AT expansion leads to ectopic fat accretion, contributing to impaired metabolic health. The role of adipogenesis as a contributing factor is debatable. SUBJECTS/METHODS: In the present analysis, we assess changes in adipocyte size distribution in relation to changes in ectopic fat accretion in response to 8-weeks of overfeeding in 22 men (28 ± 5.4 years; BMI 25.5 ± 2.3 kg/m2) who were fed 40% over their baseline energy requirements. RESULTS: Participants gained 6.7 ± 2.1 kg. The percentage of small adipocytes (p = 0.03) and the peak diameter of large adipocytes (p = 0.01) increased after overfeeding. At baseline, the percentage of small adipocytes was positively correlated with % body fat (p = 0.03), SAT mass (p = 0.01), VAT mass (p = 0.02), VAT:TAT (p = 0.05), and IHL (p = 0.09; trend). The relative (percent) change in small adipocytes was positively associated with the increase in whole-body fat (p = 0.001), VAT mass (p = 0.0003), VAT:TAT (p = 0.01), and IHL (p = 0.007) in response to overfeeding. CONCLUSIONS: These findings, surprisingly, indicate that during substantial weight gain, an increase in small adipocytes (suggesting hyperplastic expansion) is associated with impaired (not improved) metabolic health outcomes, specifically visceral and ectopic fat accumulation. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier- NCT01672632.

Longitudinal Impact of Vision Impairment on Concern About Falling in People With Age-Related Macular Degeneration.

PURPOSE: To explore the longitudinal impact of central vision loss on concern about falling (CF), over a 12-month period, in people with age-related macular degeneration (AMD). METHODS: Participants included 60 community-dwelling older people (age, 79.7 ± 6.4 years) with central vision impairment due to AMD. Binocular high-contrast visual acuity, contrast sensitivity, and visual fields were assessed at baseline and at 12 months. CF was assessed at both time points using the Falls Efficacy Scale-International (FES-I). Sensorimotor function (sit to stand, knee extension, postural sway, and walking speed) and neuropsychological function (reaction time, symptoms of anxiety and depression) were also assessed at both time points using validated instruments. Falls data were collected using monthly diaries during the 12 months. RESULTS: CF increased by a small but significant amount over the 12-month follow-up (2.1 units; P = 0.01), with increasing prevalence of high levels of CF (FES-I score ≥ 23), from 48% at baseline to 65% at 12 months. Linear mixed models showed that reduced contrast sensitivity was significantly associated with increased concern about falling (P = 0.004), whereas declines in both visual acuity and contrast sensitivity during the follow-up period were associated with increases in CF over the 12-month follow-up (P = 0.041 and P = 0.054, respectively), independent of age, gender, falls history, or number of comorbidities. CONCLUSIONS: Higher levels of CF are common in older people with AMD, and levels increase over time; this increase is associated with declines in both visual acuity and contrast sensitivity. These findings highlight the need for regular assessment of both visual acuity and contrast sensitivity to identify those at greatest risk of developing higher CF. TRANSLATIONAL RELEVANCE: Routine assessment of visual acuity and contrast sensitivity in older people with AMD will assist in identifying those at risk of developing high CF.

Pioglitazone Reverses Markers of Islet Beta-Cell De-Differentiation in db/db Mice While Modulating Expression of Genes Controlling Inflammation and Browning in White Adipose Tissue from Insulin-Resistant Mice and Humans.

Obesity, insulin resistance, and type 2 diabetes contribute to increased morbidity and mortality in humans. The db/db mouse is an important mouse model that displays many key features of the human disease. Herein, we used the drug pioglitazone, a thiazolidinedione with insulin-sensitizing properties, to investigate blood glucose levels, indicators of islet ß-cell health and maturity, and gene expression in adipose tissue. Oral administration of pioglitazone lowered blood glucose levels in db/db mice with a corresponding increase in respiratory quotient, which indicates improved whole-body carbohydrate utilization. In addition, white adipose tissue from db/db mice and from humans treated with pioglitazone showed increased expression of glycerol kinase. Both db/db mice and humans given pioglitazone displayed increased expression of UCP-1, a marker typically associated with brown adipose tissue. Moreover, pancreatic ß-cells from db/db mice treated with pioglitazone had greater expression of insulin and Nkx6.1 as well as reduced abundance of the de-differentiation marker Aldh1a3. Collectively, these findings indicate that four weeks of pioglitazone therapy improved overall metabolic health in db/db mice. Our data are consistent with published reports of human subjects administered pioglitazone and with analysis of human adipose tissue taken from subjects treated with pioglitazone. In conclusion, the current study provides evidence that pioglitazone restores key markers of metabolic health and also showcases the utility of the db/db mouse to understand mechanisms associated with human metabolic disease and interventions that provide therapeutic benefit.

Exercise reduced the formation of new adipocytes in the adipose tissue of mice in vivo.

Exercise has beneficial effects on metabolism and health. Although the skeletal muscle has been a primary focus, exercise also mediates robust adaptations in white adipose tissue. To determine if exercise affects in vivo adipocyte formation, fifty-two, sixteen-week-old C57BL/6J mice were allowed access to unlocked running wheels [Exercise (EX) group; n = 13 males, n = 13 females] or to locked wheels [Sedentary (SED) group; n = 13 males, n = 13 females] for 4-weeks. In vivo adipocyte formation was assessed by the incorporation of deuterium (2H) into the DNA of newly formed adipocytes in the inguinal and gonadal adipose depots. A two-way ANOVA revealed that exercise significantly decreased new adipocyte formation in the adipose tissue of mice in the EX group relative to the SED group (activity effect; P = 0.02). This reduction was observed in male and female mice (activity effect; P = 0.03). Independent analysis of the depots showed a significant reduction in adipocyte formation in the inguinal (P = 0.05) but not in the gonadal (P = 0.18) of the EX group. We report for the first time that exercise significantly reduced in vivo adipocyte formation in the adipose tissue of EX mice using a physiologic metabolic 2H2O-labeling protocol.

Determinants of concern about falling in adults with age-related macular degeneration.

PURPOSE: To investigate the prevalence and level of concern about falling (CF) among older people with vision impairment due to age-related macular degeneration (AMD) compared to a visually normal control group, and to identify determinants of CF for the AMD group. METHODS: Participants included 133 older people: 77 with AMD (mean age = 80.5 ± 6.2 years), and 56 controls (mean age = 75.4 ± 5.3 years). Binocular visual acuity, contrast sensitivity and visual fields were measured, and CF was assessed using the Falls Efficacy Scale - International (FES-I). Data were also collected for sensorimotor function (postural sway, sit-to-stand, knee extensions, walking speed, proprioception), and neuropsychological function (reaction time, symptoms of anxiety and depression) using validated tests and scales. RESULTS: Concern about falling scores were higher for AMD participants compared to control participants (mean ± S.D. 24.6 ± 8.0 vs 21.6 ± 5.7, p = 0.02, respectively), although these findings failed to reach significance when adjusted for age (p = 0.16). Among AMD participants, multivariable models showed that greater CF was associated with reduced contrast sensitivity (p = 0.02), slower sit-to-stand times (p < 0.001) and higher anxiety scores (p < 0.001); these factors explained 40% of the variance in CF (p < 0.01). CONCLUSION: Levels of CF in older people with AMD were not found to be elevated by their disease status alone, but rather by the extent of vision loss. Levels of CF in those with AMD were associated with various visual, sensorimotor and neuropsychological factors. These findings will assist clinicians in identifying those at greatest risk of developing high CF and inform the design of future intervention programmes for this population.

Adipose depot-specific effects of 16 weeks of pioglitazone on in vivo adipogenesis in women with obesity: a randomised controlled trial.

AIMS/HYPOTHESIS: In vitro and rodent studies suggest that pioglitazone, a thiazolidinedione, can promote adipogenesis in adipose tissue (AT); however, there is a lack of in vivo studies in humans to support these findings. The objectives of this randomised, placebo-controlled, parallel-arm trial were to test if pioglitazone stimulates in vivo adipogenesis in the subcutaneous adipose tissue depots and if these measures were related to metabolic health outcomes in women with obesity. METHODS: Forty-one healthy women with obesity (20 black; 21 white; 29 ± 6 years; BMI 32.0 ± 1.7 kg/m2; 44.0 ± 3.6% body fat) were randomised to consume 30 mg/day of pioglitazone (n = 21) or placebo (n = 20) for 16 weeks. SAS v9.4 was used to generate the block randomisation code sequence (stored in password-protected files) with a 1:1 allocation ratio. The participants and study staff involved in assessing and analysing data outcomes were blinded to the group assignments. The trial was conducted at Pennington Biomedical Research Center and ended in 2016. At baseline and post-intervention, subcutaneous abdominal (scABD) and femoral (scFEM) AT biopsies were collected, and in vivo cellular kinetics (primary endpoint of the trial) were assessed by an 8 week labelling protocol of deuterium (2H) into the DNA of adipose cells. Body composition was measured by dual-energy x-ray absorptiometry (DXA), scABD and visceral AT (VAT) by MRI, ectopic fat by 1H-MRS, and insulin sensitivity by an OGTT. RESULTS: After the 16 week intervention, there was a significant decrease in visceral fat (VAT:total abdominal AT [as a %]; p = 0.002) and an increase in the Matsuda index (i.e. improved insulin sensitivity; p = 0.04) in the pioglitazone group relative to the placebo group. A significant increase in the formation of new adipocytes was observed in the scFEM (Δ = 3.3 ± 1.6%; p = 0.04) but not the scABD depot (Δ = 2.0 ± 2.1%; p = 0.32) in the pioglitazone group relative to the placebo group. No serious adverse events were reported. CONCLUSIONS/INTERPRETATION: Pioglitazone may elicit distinct differences in in vivo adipogenesis in subcutaneous adipose depots in women with obesity, with increased rates in the protective scFEM. Trial registration ClinicalTrials.gov NCT01748994 Funding This study was funded by R01DK090607, P30DK072476, and R03DK112006 from the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health. U54 GM104940 from the National Institute of General Medical Sciences of the National Institutes of Health. The Robert C. and Veronica Atkins Foundation. Graphical abstract.

Association of Baseline and Longitudinal Changes in Body Composition Measures With Risk of Heart Failure and Myocardial Infarction in Type 2 Diabetes: Findings From the Look AHEAD Trial.

BACKGROUND: Intentional weight loss is associated with lower risk of heart failure (HF) and atherosclerotic cardiovascular disease among patients with type 2 diabetes. However, the contribution of baseline measures and longitudinal changes in fat mass (FM), lean mass (LM), and waist circumference (WC) to the risk of HF and myocardial infarction (MI) in type 2 diabetes is not well established. METHODS: Adults from the Look AHEAD trial (Action for Health in Diabetes) without prevalent HF were included. FM and LM were predicted using validated equations and compared with dual-energy x-ray absorptiometry measurements in a subgroup. Adjusted Cox models were used to evaluate the associations of baseline and longitudinal changes in FM, LM, and WC over 1- and 4-year follow-up with risk of overall HF, HF with preserved ejection fraction (EF; EF ≥50%), HF with reduced EF (EF <50%), and MI. RESULTS: Among 5103 participants, there were 257 incident HF events over 12.4 years of follow-up. Predicted and measured FM/LM were highly correlated (R2=0.87-0.90; n=1369). FM and LM decreased over 4-year follow-up with greater declines in the intensive lifestyle intervention arm. In adjusted analysis, baseline body composition measures were not significantly associated with HF risk. Decline in FM and WC, but not LM, over 1 year were each significantly associated with lower risk of overall HF (adjusted hazard ratio per 10% decrease in FM, 0.80 [95% CI, 0.68-0.95]; adjusted hazard ratio per 10% decrease in WC, 0.77 [95% CI, 0.62-0.95]). Decline in FM was significantly associated with lower risk of both HF subtypes. In contrast, decline in WC was significantly associated with lower risk of HF with preserved EF but not HF with reduced EF. Similar patterns of association were observed for 4-year changes in body composition and HF risk. Longitudinal changes in body composition were not significantly associated with risk of MI. CONCLUSIONS: In adults with type 2 diabetes, a lifestyle intervention is associated with significant loss of FM and LM. Declines in FM and WC, but not LM, were each significantly associated with lower risk of HF but not MI. Furthermore, decline in WC was significantly associated with lower risk of HF with preserved EF but not HF with reduced EF. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00017953.

The Effects of Alcohol Consumption on Cardiometabolic Health Outcomes Following Weight Loss in Premenopausal Women with Obesity: A Pilot Randomized Controlled Trial.

Alcohol (i.e., ethanol) is consumed regularly by much of the adult population; yet, the health effects associated with its use are not well-characterized. Clinical interventions to investigate the effects of moderate alcohol consumption on metabolic outcomes, including adiposity and cardiovascular risk factors, are limited and have yielded conflicting data. In addition, no study has reported the effects of routine alcohol intake during weight loss in a controlled feeding trial. We present the first randomized controlled pilot trial to investigate the effects of moderate alcohol consumption on metabolic outcomes during weight loss in women with obesity. Both groups consumed 30% energy restricted diets and were randomized to either an ethanol-free control (CTL) group or a group (EtOH) that consumed 35 g ethanol daily for eight weeks. Our findings demonstrate that, despite similar weight loss, the decrease in mean arterial pressure was attenuated in the EtOH group, relative to the CTL group (p = 0.02). In addition, decreases in other outcomes, including visceral adipose tissue (p = 0.23), circulating lipids (triglycerides (p = 0.11) and cholesterol (p = 0.11)), and uric acid (p = 0.07) tended to be attenuated with alcohol consumption. These pilot data provide potential evidence that moderate alcohol consumption may mitigate the beneficial effects of weight loss and support the need for larger Randomized Controlled Trials (RCTs) to better investigate the metabolic effects of moderate alcohol intake in humans.

Resistant Starch Has No Effect on Appetite and Food Intake in Individuals with Prediabetes.

BACKGROUND: Type 2 resistant starch (RS2) has been shown to improve metabolic health outcomes and may increase satiety and suppress appetite and food intake in humans. OBJECTIVE: This study assessed whether 12 weeks of daily RS2 supplementation could influence appetite perception, food intake, and appetite-related gut hormones in adults with prediabetes, relative to the control (CTL) group. DESIGN: The study was a randomized controlled trial and analysis of secondary study end points. PARTICIPANTS/SETTING: Sixty-eight adults (body mass index ≥27) aged 35 to 75 years with prediabetes were enrolled in the study at Pennington Biomedical Research Center (2012 to 2016). Fifty-nine subjects were included in the analysis. INTERVENTION: Participants were randomized to consume 45 g/day of high-amylose maize (RS2) or an isocaloric amount of the rapidly digestible starch amylopectin (CTL) for 12 weeks. MAIN OUTCOME MEASURES: Subjective appetite measures were assessed via visual analogue scale and the Eating Inventory; appetite-related gut hormones (glucagon-like peptide 1, peptide YY, and ghrelin) were measured during a standard mixed-meal test; and energy and macronutrient intake were assessed by a laboratory food intake (buffet) test, the Remote Food Photography Method, and SmartIntake app. STATISTICAL ANALYSES PERFORMED: Data were analyzed using linear mixed models, adjusting for treatment group and time as fixed effects, with a significance level of α=.05. RESULTS: RS2 had no effect on subjective measures of appetite, as assessed by visual analogue scale (P>0.05) and the Eating Inventory (P≥0.24), relative to the CTL group. There were no effects of RS2 supplementation on appetite-related gut hormones, including glucagon-like peptide 1 (P=0.61), peptide YY (P=0.34), and both total (P=0.26) and active (P=0.47) ghrelin compared with the CTL. RS2 had no effect on total energy (P=0.30), carbohydrate (P=0.11), protein (P=0.64), or fat (P=0.37) consumption in response to a buffet meal test, relative to the CTL. In addition, total energy (P=0.40), carbohydrate (P=0.15), protein (P=0.46), and fat (P=0.53) intake, as quantified by the Remote Food Photography Method, were also unaffected by RS2, relative to the CTL. CONCLUSIONS: RS2 supplementation did not increase satiety or reduce appetite and food intake in adults with prediabetes.

Racial Variations in Appetite-Related Hormones, Appetite, and Laboratory-Based Energy Intake from the E-MECHANIC Randomized Clinical Trial.

African Americans (AAs) have a higher obesity risk than Whites; however, it is unclear if appetite-related hormones and food intake are implicated. We examined differences in appetite-related hormones, appetite, and food intake between AAs (n = 53) and Whites (n = 111) with overweight or obesity. Participants were randomized into a control group or into supervised, controlled exercise groups at 8 kcal/kg of body weight/week (KKW) or 20 KKW. Participants consumed lunch and dinner at baseline and follow-up, with appetite and hormones measured before and after meals (except leptin). At baseline, AAs had lower peptide YY (PYY; p < 0.01) and a blunted elevation in PYY after lunch (p = 0.01), as well as lower ghrelin (p = 0.02) and higher leptin (p < 0.01) compared to Whites. Despite desire to eat being lower and satisfaction being higher in AAs relative to Whites (p ≤ 0.03), no racial differences in food intake were observed. Compared to Whites, leptin increased in the 8 KKW group in AAs (p = 0.01), yet no other race-by-group interactions were evident. Differences in appetite-related hormones between AAs and Whites exist; however, their influence on racial disparities in appetite, food intake, and obesity within this trial was limited.

The Expression of Adipose Tissue-Derived Cardiotrophin-1 in Humans with Obesity.

Cardiotrophin-1 (CT-1) is a gp130 cytokine that was previously characterized for its effects on cardiomyocytes and identified as a marker of heart failure. More recent studies reported elevated circulating levels of CT-1 in humans with obesity and metabolic syndrome (MetS). However, a subsequent rodent study implicated CT-1 as a potential therapeutic target for obesity and MetS. Adipose tissue (AT) is broadly acknowledged as an endocrine organ and is a substantial source of CT-1. However, no study has examined the expression of adipose-derived CT-1 in humans. We present the first analysis of CT-1 mRNA expression in subcutaneous AT and its association with clinical variables in 22 women with obesity and 15 men who were 40% overfed for 8-weeks. We observed that CT-1 expression was higher in the subcutaneous abdominal (scABD) than the femoral (scFEM) depot. Importantly, we reveal that scFEM but not scABD, CT-1 expression was negatively associated with visceral adiposity and intrahepatic lipid, while positively correlated with insulin sensitivity in obese women. Also, men with higher CT-1 levels at baseline had less of a decline in insulin sensitivity in response to overfeeding. Our data provide new knowledge on the regulation of adipose-derived CT-1 in obesity and during weight gain in response to overfeeding in humans and suggest that CT-1 may play a protective role in obesity and related disorders.

Dynamics of adipose tissue turnover in human metabolic health and disease.

White adipose tissue is a highly plastic organ and is an important regulator of whole-body metabolism and energy balance. The magnitude of adipose tissue mass is determined by dynamic changes in the synthesis and breakdown (i.e. turnover) of adipocytes and triacylglycerols (TGs). Obesity is a disorder characterised by excessive adiposity and is a risk factor for diseases, including the metabolic syndrome and type 2 diabetes. Adipose tissue expansion is necessary to accommodate chronic excess energy intake and is characterised by enlargement of existing adipocytes (hypertrophy) and by increase in pre-adipocyte and adipocyte numbers (hyperplasia). Evidence suggests that the manner of subcutaneous adipose expansion can influence metabolic health, as impaired adipogenesis, namely restricted hyperplasia, may lead to ectopic lipid deposition in the liver and skeletal muscle, contributing to the pathogenesis of obesity-related disorders. Despite the plausible role of adipose turnover in human health and pathology, little is known about the in vivo kinetics of adipose tissue components (both adipose cells and TGs). This is due, in part, to the slow turnover rate of adipose tissue and the complexity of directly labelling pathway precursors. This review provides a brief summary of findings derived from in vitro techniques, as well as an overview of two in vivo methods that are being implemented to assess the turnover of adipose cells and TGs. Finally, the role of adipose tissue turnover in metabolic health and disease is discussed.

Racial differences in in vivo adipose lipid kinetics in humans.

The storage of lipids in the form of triglycerides (TGs) and the de novo synthesis (lipogenesis) of fatty acids from nonlipid precursors [de novo lipogenesis (DNL)] are important functions of adipose tissue (AT) that influence whole-body metabolism. Yet, few studies have reported in vivo estimates of adipose lipid kinetics in humans. Fifty-two women with obesity (27 African-American and 25 Caucasian; 29.7 ± 5.5 years; BMI 32.2 ± 2.8 kg/m2; 44.3 ± 4.0% body fat) were enrolled in the study. In vivo synthesis (or replacement) of TGs (fTG) as well as the synthesis of the fatty acid, palmitate [a measure of adipose DNL (fDNL)], were assessed using an 8 week incorporation of deuterium into lipids (glycerol and palmitate moieties of TGs) in subcutaneous abdominal (scABD) and subcutaneous femoral (scFEM) AT. We report, for the first time, significant race differences in both TG synthesis and absolute DNL, with Caucasians having higher fTG and fDNL as compared with African-Americans. The DNL contribution to newly synthesized TG (corrected fDNL) was not different between races. Interestingly, our findings also show that the scFEM adipose depot had higher TG replacement rates relative to the scABD. Finally, the replacement rate of TG (fTG) was negatively correlated with changes in body weight over the 8 week labeling period. Our results provide the first evidence that in vivo TG replacement (synthesis and breakdown) rates differ by ethnicity. In addition, TG turnover varies by depot location in humans, implying an increased capacity for TG storage and higher lipolytic activity in the scFEM AT.

Role of resistant starch on diabetes risk factors in people with prediabetes: Design, conduct, and baseline results of the STARCH trial.

Dietary resistant starch (RS) might alter gastrointestinal tract function in a manner that improves human health, particularly among adults at risk for diabetes. Here, we report the design and baseline results (with emphasis on race differences) from the STARCH trial, the first comprehensive metabolic phenotyping of people with prediabetes enrolled in a randomized clinical trial testing the effect of RS on risk factors for diabetes. Overweight/obese participants (BMI≥27kg/m2 and weight≤143kg), age 35-75y, with confirmed prediabetes were eligible. Participants were randomized to consume 45g/day of RS (RS=amylose) or amylopectin (Control) for 12weeks. The study was designed to evaluate the effect of RS on insulin sensitivity and secretion, ectopic fat, and inflammatory markers. Secondary outcomes included energy expenditure, substrate oxidation, appetite, food intake, colonic microbial composition, fecal and plasma levels of short-chain fatty acids, fecal RS excretion, and gut permeability. Out of 280 individuals screened, 68 were randomized, 65 started the intervention, and 63 were analyzed at baseline (mean age 55y, BMI 35.6kg/m2); 2 were excluded from baseline analyses due to abnormal insulin and diabetes. Sex and race comparisons at baseline were reported. African-Americans had higher baseline acute insulin response to glucose (AIRg measured by frequently sampled intravenous glucose tolerance test) compared to Caucasians, despite having less visceral adipose tissue mass and intrahepatic lipid; all other glycemic variables were similar between races. Sleep energy expenditure was ~90-100kcal/day lower in African-Americans after adjusting for insulin sensitivity and secretion. This manuscript provides an overview of the strategy used to enroll people with prediabetes into the STARCH trial and describes methodologies used in the assessment of risk factors for diabetes. Clinicaltrials.gov identifier: STARCH (NCT01708694). The present study reference can be found here: https://clinicaltrials.gov/ct2/show/NCT01708694. Submission Category: "Study Design, Statistical Design, Study Protocols".

Association of In Vivo Adipose Tissue Cellular Kinetics With Markers of Metabolic Health in Humans.

Context: Adipose tissue (AT) expansion occurs by hypertrophy and hyperplasia. Impaired hyperplasia, or adipogenesis, has been associated with obesity-related diseases. Objective: We examined how in vivo adipogenesis in the subcutaneous abdominal (scABD) and femoral (scFEM) depots (via 8-week incorporation of deuterium) correlates with markers of metabolic health. Design: Data from 52 women with obesity [27 black and 25 white; 29.7 ± 5.5 years; body mass index (BMI) 32.2 ± 2.8 kg/m2; 44.3% ± 4.0% body fat] were analyzed at Pennington Biomedical Research Center. Main Outcomes: A linear repeated measure model was used to assess the fraction of new adipose cells and the associated covariates. Akaike information criterion determined the covariates that best described the data. Simple associations were examined using Spearman's correlation. Results: The covariates that were associated with adipose kinetics included BMI, visceral AT/total abdominal AT (VAT/TAT) ratio, and the Matsuda index. Simple correlations demonstrated that adipocyte and preadipocyte formation in scABD (P = 0.02 and P = 0.16, trend, respectively) and scFEM (P = 0.01 and P = 0.24, trend, respectively) depots correlated positively with VAT/TAT. Preadipocyte and adipocyte formation in the scABD (P < 0.0001 and P = 0.02, respectively) and scFEM (P = 0.0001 and P = 0.003, respectively) was negatively associated with insulin sensitivity. Conclusions: Our results challenge the AT expandability hypothesis and suggest that higher in vivo adipose cell turnover is positively associated with BMI and VAT/TAT and negatively associated with insulin sensitivity, all correlates of impaired metabolic health.

Differences in In Vivo Cellular Kinetics in Abdominal and Femoral Subcutaneous Adipose Tissue in Women.

The accumulation of fat in upper-body (abdominal) adipose tissue is associated with obesity-related cardiometabolic diseases, whereas lower-body (gluteal and femoral) fat may be protective. Studies suggest physiological and molecular differences between adipose depots and depot-specific cellular mechanisms of adipose expansion. We assessed in vivo cellular kinetics in subcutaneous adipose tissue from the abdominal (scABD) and femoral (scFEM) depots using an 8-week incorporation of deuterium ((2)H) from (2)H2O into the DNA of adipocytes and preadipocytes in 25 women with overweight or obesity. DNA synthesis rates denote new cell formation of preadipocytes and adipocytes in each depot. Formation of adipocytes was positively correlated to that of preadipocytes in the scABD and scFEM depots and was related to percent body fat in each depot. Notably, preadipocytes and adipocytes had higher formation rates in the scFEM depot relative to the scABD. This method to assess in vivo adipogenesis will be valuable to evaluate adipocyte kinetics in individuals with varying body fat distributions and degrees of metabolic health and in response to a variety of interventions, such as diet, exercise, or pharmacological treatment.

The modulation of adiponectin by STAT5-activating hormones.

Adiponectin is a hormone secreted from adipocytes that plays an important role in insulin sensitivity and protects against metabolic syndrome. Growth hormone (GH) and prolactin (PRL) are potent STAT5 activators that regulate the expression of several genes in adipocytes. Studies have shown that the secretion of adiponectin from adipose tissue is decreased by treatment with PRL and GH. In this study, we demonstrate that 3T3-L1 adipocytes treated with GH or PRL exhibit a reduction in adiponectin protein levels. Furthermore, we identified three putative STAT5 binding sites in the murine adiponectin promoter and show that only one of these, located at -3,809, binds nuclear protein in a GH- or PRL-dependent manner. Mutation of the STAT5 binding site reduced PRL-dependent protein binding, and supershift analysis revealed that STAT5A and -5B, but not STAT1 and -3, bind to this site in response to PRL. Chromatin immunoprecipitation (IP) analysis demonstrated that only STAT5A, and not STAT1 and -3, bind to the murine adiponectin promoter in a GH-dependent manner in vivo. Adiponectin promoter/reporter constructs were responsive to GH, and chromatin IP analysis reveals that STAT5 binds the adiponectin promoter in vivo following GH stimulation. Overall, these data strongly suggest that STAT5 activators regulate adiponectin transcription through the binding of STAT5 to the -3,809 site that leads to decreased adiponectin expression and secretion. These mechanistic observations are highly consistent with studies in mice and humans that have high GH or PRL levels that are accompanied by lower circulating levels of adiponectin.

Fear of falling in vision impairment.

Falls are the leading cause of injury-related morbidity and mortality among older adults. In addition to the resulting physical injury and potential disability after a fall, there are also important psychological consequences, including depression, anxiety, activity restriction, and fear of falling. Fear of falling affects 20 to 43% of community-dwelling older adults and is not limited to those who have previously experienced a fall. About half of older adults who experience fear of falling subsequently restrict their physical and everyday activities, which can lead to functional decline, depression, increased falls risk, and reduced quality of life. Although there is clear evidence that older adults with visual impairment have higher falls risk, only a limited number of studies have investigated fear of falling in older adults with visual impairment and the findings have been mixed. Recent studies suggest increased levels of fear of falling among older adults with various eye conditions, including glaucoma and age-related macular degeneration, whereas other studies have failed to find differences. Interventions, which are still in their infancy in the general population, are also largely unexplored in those with visual impairment. The major aims of this review were to provide an overview of the literature on fear of falling, its measurement, and risk factors among older populations, with specific focus on older adults with visual impairment, and to identify directions for future research in this area.