Measures Of Insulin Sensitivity Research Articles

Impact of Exercise Manual Program on Biochemical Markers in Sedentary Prediabetic Patients: A Randomized Controlled Trial

Background and Objectives: Prediabetes is a medical disease characterized by elevated blood sugar levels that exceed normal levels but do not meet the criteria for a diagnosis of diabetes mellitus. This study aimed to assess the impact of structured exercise manual interventions on the biochemical markers of sedentary prediabetic patients over sixteen weeks. Materials and Methods: A sixteen-weeks randomized controlled trial was conducted to assess the impact of an exercise-based manual program on biochemical markers, such as HbA1c, insulin sensitivity measures, and lipid profiles, in sedentary individuals with prediabetes. The Riphah Rehabilitation Center in Lahore, Pakistan, was the site of the trial. In this investigation, 126 individuals with prediabetes were randomly assigned to three groups: control, unsupervised, and supervised. The RCT was completed by 36 participants in each group after a 16-weeks intervention in the supervised and unsupervised groups, as well as a follow-up in the control group. An activity-based exercise manual that included dietary guidelines, educational materials, and an exercise routine was followed by both the supervised and unsupervised groups. The exercise interventions included both aerobic and resistance components. Results: The results indicated that the supervised group exhibited a substantial increase in insulin sensitivity, lipid profiles, and glycemic control when contrasted with the unsupervised and control groups. Significant improvements were observed in key biochemical parameters, including fasting blood levels (supervised as compared to unsupervised and control, respectively, the mean difference was 12.82 mg/dL vs. 11.36 mg/dL vs. 0.09 mg/dL p > 0.001), HbA1c (supervised as compared to unsupervised and control groups, respectively, the mean difference was 0.67% vs. 0.69% vs. 0.13% p < 0.001), and lipid profile (triglycerides (mean difference 0.25 mmol/L, 0.08 mmol/L, 0.11 mmol/L p < 0.001); LDL (mean difference 19.31 mg/dL, 10.51 mg/dL, 2.49 mg/dL p < 0.001); HDL (mean difference −12.68 mg/dL, −8.03 mg/dL, −1.48 mg/dL p < 0.001)). In comparison to the unsupervised and control groups, the insulin sensitivity parameters also demonstrated a modest improvement in the supervised group. The supervised group exhibited the greatest benefits from exercise among the groups that received exercise interventions. Conclusions: The present investigation demonstrated the significance of including structured physical activity into the regular routine of individuals with prediabetes, to decelerate the advancement of prediabetes to type 2 diabetes mellitus (T2DM). The current study emphasizes the essential role of structured exercise routines in the control of prediabetes and suggests that monitoring enhances the adherence and effectiveness of lifestyle interventions.

A critique of measurement of defective insulin secretion and insulin sensitivity as a precision approach to gestational diabetes.

Precision medicine approaches to gestational diabetes mellitus (GDM) have categorised patients according to disease pathophysiology (insulin resistance, insulin insufficiency or both), and demonstrated associations with clinical outcomes. We aimed to assess whether using enhanced processing to determine indices of insulin secretion and sensitivity is analytically robust, reproducible in a different population, and useful diagnostically and prognostically in clinical practice. A total of 1308 pregnant women with one or more risk factors for GDM who underwent a 75 g OGTT at one of nine hospital sites were recruited to this observational study. Specimens were collected for determination of glucose levels using standard and enhanced procedures, HbA1c and insulin analysis. GDM diagnosis and management followed National Institute for Health and Care Excellence guidance. We categorised women into pathophysiological subtypes: insulin-resistant GDM (HOMA2-S < 25th centile of the population with normal glucose tolerance [NGT]), insulin-insufficient GDM (HOMA2-B < 25th centile), both or neither. We assessed associations with pregnancy outcomes using logistic regression. Using enhanced specimen handling, 1027/1308 (78.5%) women had NGT, with 281/1308 (21.5%) being classified as having GDM. Of this group, 135/281 (48.0%) had insulin-resistant GDM, 73/281 (26.0%) had insulin-insufficient GDM and 2/281 (0.7%) had both insulin-resistant and insulin-insufficient GDM. Unexpectedly, 71 patients (25.3%) had GDM with both HOMA2-S and HOMA2-B ≥25th centile (GDM-neither). This novel subgroup appeared to be relatively insulin-sensitive in the fasting state but developed marked post-load hyperglycaemia and hyperinsulinaemia, suggesting an isolated postprandial defect in insulin sensitivity that was not captured by HOMA2-B or HOMA2-S. Women within most GDM subgroups had comparable pregnancy outcomes to those of normoglycaemic women, and HOMA2-B and HOMA2-S were weak predictors of pregnancy outcomes. Maternal BMI predicted a similar number of outcomes to HOMA2-S, suggesting that there was no additional predictive value in adding HOMA2-S. Similar findings were obtained when using different indices and standard specimen handling techniques. Precision categorisation of GDM using HOMA2-S and HOMA2-B does not provide useful diagnostic or prognostic information, but did distinguish a novel subgroup of patients with GDM, characterised by an isolated postprandial defect in insulin sensitivity.

Cross-sectional, interventional, and causal investigation of insulin sensitivity using plasma proteomics in diverse populations.

We previously reported significant correlations between a direct measure of insulin sensitivity (IS) and blood levels of proteins measured using the Proximity Extension Assay (PEA) in two European cohorts. However, protein correlations with IS within non-European populations, in response to short-term interventions that improve IS, and any causal associations with IS have not yet been established. We measured 1,470 proteins using the PEA in the plasma of 1,015 research participants at Stanford University who underwent one or more direct measures of IS. Association analyses were carried out with multivariable linear regression within and across Stanford subgroups and within each of the two European cohorts. Association statistics were also meta-analyzed after transformation and harmonization of the two direct measures of IS. Lastly, we performed genome-wide association studies of IS and used genetic instruments of plasma proteins from the UK Biobank to identify candidate causal proteins for IS through Mendelian Randomization (MR) analysis. In age and sex adjusted model, 810 proteins were associated with baseline IS among 652 self-reported European participants in the Stanford cohort at a false discovery rate (FDR) < 0.05. Effect sizes for these proteins were highly correlated with those observed in 122 South Asian, 92 East Asian, 85 Hispanic, and 52 Black/African American persons (r= 0.68 to 0.83, all P≤4.3×10-113). Meta-analysis of the full Stanford cohort with the two European cohorts (N=2,945) yielded 247 significant protein associations (FDR < 0.05), with 75 remaining significant after further adjustment for body mass index. In a subset of Stanford participants undergoing insulin sensitizing interventions (N=53 taking thiazolidinediones, N=66 with weight loss), 79.6% of protein level changes were directionally consistent with the respective baseline association (observed/expected p=6.7×10-16). MR analyses identified eight candidate causal proteins for IS, among which were SELE and ASGR1, proteins with established drug targets currently under investigation. Plasma proteins measured using the PEA provide a robust signature for IS across diverse populations and after short-term insulin sensitizing interventions highlighting their potential value as universal biomarkers of insulin resistance. A small subset of markers provided insights into potential causal molecular mechanisms and therapeutic targets.

Comparison of protective effects of teneligliptin and luseogliflozin on pancreatic β-cell function: randomized, parallel-group, multicenter, open-label study (SECRETE-I study).

The aim of this study is to directly compare the effects of SGLT2 inhibitors and DPP-4 inhibitors on β-cell function in patients with type 2 diabetes. We conducted a 26-week, randomized, open-label, parallel-group study, including a 1-2 week drug washout period, in patients with type 2 diabetes with HbA1c ≥7.0% and <9.0% and BMI ≥20 kg/m2 despite treatment with a drug naïve or other than DPP-4 inhibitors or SGLT2 inhibitors. A total of 103 subjects were randomly assigned to receive once daily oral luseogliflozin (L) or teneligliptin (T). The primary endpoint was the effect of L vs. T on the change in logarithmus naturalis (Ln) disposition index (DI) (DI 0-120min; combining measures of insulin secretion and sensitivity) from baseline to week 25-26 (post intervention), which was calculated by conducting an oral glucose tolerance test. Ln DI 0-120min were improved in both groups: -0.46 ± 0.68 to -0.20 ± 0.59 (p=0.03) in L group and -0.26 ± 0.60 to -0.05 ± 0.62 (p=0.01) in T group. The change in Ln serum proinsulin/C-peptide ratio, a marker of β-cell dysfunction, was reduced in L group (1.63 ± 0.63 to 1.56 ± 0.68, p=0.16), but rather increased in T group (1.70 ± 0.75 to 1.90 ± 0.51, p=0.01), with significant difference between the two groups (-0.27; p=0.004). Improvement of disposition index in subjects with obese type 2 diabetes was comparable between luseogliflozin and teneligliptin. On the other hand, it is likely that alleviation of β-cell dysfunction is more effective with luseogliflozin compared to tenegliptin. https://rctportal.niph.go.jp/en, identifier jRCTs061190008.

Development of a Diabetes Dietary Quality Index: Reproducibility and Associations with Measures of Insulin Resistance, Beta Cell Function, and Hyperglycemia.

Various dietary risk factors for type 2 diabetes have been identified. A short assessment of dietary patterns related to the risk for type 2 diabetes mellitus may be relevant in clinical practice given the largely preventable nature of the disease. The aim of this study was to investigate the reproducibility of a short food frequency questionnaire based on available knowledge of diabetes-related healthy diets. In addition, we aimed to investigate whether a Diabetes Dietary Quality Index based on this questionnaire was related to metabolic risk factors, including measures of beta cell function and insulin sensitivity. A short food frequency questionnaire was composed by selecting fourteen questions (representing eight dietary factors) from existing food frequency questionnaires on the basis of their reported relationship with diabetes risk. Healthy participants (N = 176) from a Dutch family study completed the questionnaire and a subgroup (N = 123) completed the questionnaire twice. Reproducible items from the short questionnaire were combined into an index. The association between the Diabetes Dietary Quality index and metabolic risk factors was investigated using multiple linear regression analysis. Measures of beta cell function and insulin sensitivity were derived from a mixed meal test and an euglycemic-hyperinsulinemic and modified hyperglycemic clamp test. Our results show that this new short food frequency questionnaire is reliable (Intraclass Correlations ranged between 0.5 and 0.9). A higher Diabetes Dietary Quality index score was associated with lower 2 h post-meal glucose (β -0.02, SE 0.006, p < 0.05), HbA1c (β -0.07, SE 0.02, p < 0.05), total cholesterol, (β -0.02, SE 0.07, p < 0.05), LDL cholesterol, (β -0.19, SE 0.07, p < 0.05), fasting (β -0.4, SE 0.16, p < 0.05) and post-load insulin, (β -3.9, SE 1.40, p < 0.05) concentrations and the incremental AUC of glucose during MMT (β -1.9, SE 0.97, p < 0.05). The scores obtained for the oral glucose insulin sensitivity-derived mixed meal test were higher in subjects who scored higher on the Diabetes Dietary Quality index (β 0.89, 0.39, p < 0.05). In contrast, we found no significant associations between the Diabetes Dietary Quality index and clamp measures of beta cell function. We identified a questionnaire-derived Diabetes Dietary Quality index that was reproducible and inversely associated with a number of type 2 diabetes mellitus and metabolic risk factors, like 2 h post-meal glucose, Hba1c and LDL, and total cholesterol. Once relative validity has been established, the Diabetes Dietary Quality index could be used by health care professionals to identify individuals with diets adversely related to development of type 2 diabetes.

6711 Single Nuclei RNA-seq To Map Adipose Cellular Populations And Senescent Cells In Response To A Lifestyle Or Senolytic Intervention In Older Adults With Obesity: A Double-Blind, Placebo-Controlled, Randomized Trial

Abstract Disclosure: A. Aslamy: None. G. Connolly: None. J. Nie: None. S. Espinoza: None. M. Serra: None. N. Musi: None. It is well established that obese and older individuals are at significantly increased risk for diabetes and metabolic syndrome. However, the underlying molecular mechanisms by which increased adiposity and aging predisposes individuals to metabolic disease are not well understood. Recent data suggests that variations in adipocyte cellular populations and subpopulations influence whole body metabolism. Particularly, an increased burden of adipocyte senescent cells (cells that are in a state of replicative arrest) have been implicated in metabolic diseases. To investigate the relationship between adipose molecular signatures and cellular senescence on metabolic outcomes, we will use a novel, high-throughput, high-resolution methodology called single nuclei RNA sequencing (SnRNA-seq) to develop a transcriptomic atlas of human adipose tissue and analyze molecular profiles before and after interventions of lifestyle vs. senolytic vs. placebo. We will recruit a cohort of older obese participants (≥65 years of age; BMI = 30-39.9 kg/m2; n = 72), and conduct a double-blinded, placebo-controlled, randomized trial in which we obtain adipose biopsies to analyze cellular/molecular profiling via snRNA-seq as it relates to phenotypic measures of insulin sensitivity, glucose tolerance, beta cell function, and hepatic lipid content compared to cohorts of younger lean (18-30 years of age; BMI = 18.5-24.9 kg/m2; n = 24) and older lean (≥65 years of age; BMI = 18.5-24.9 kg/m2; n = 24) participants. Older obese participants will be randomized to one of three groups for a 10-week period: lifestyle (diet- and exercise-induced weight loss of 8-10% of body mass), senolytic (dasatinib and quercetin), or placebo. Repeat adipose biopsies and metabolic testing will be analyzed before and after intervention to assess potential changes in gene expression and associated phenotypic measures. Inclusion criteria for the older obese participants are the following: ≥65 years of age, BMI 30-39.9 kg/m2, any sex, race and ethnic group, sedentary (≤1.5h of exercise per week), and nondiabetic. Exclusion criteria include history of diabetes, participation in structured exercise &amp;gt;1.5h per week, chronic inflammatory/neurologic/autoimmune/pulmonary disorders, GI or heart disease, use of anti-arrhythmic or weight altering medications, smoking/alcohol use, previous bariatric surgery, and use of/allergy to senolytic agents. Preliminary snRNA-seq analyses of adipose biopsies from our pilot study with non-diabetic participants identified cells with elevated expression of positive regulators of senescence (CDKN1A, CDKN2A, ARG2); notably, one subpopulation of senescent adipocytes, termed NewA1, was increased with higher BMI. Overall, the findings from this study may help us gain better understanding of the aging process and identify potential molecular targets for prevention of metabolic disease. Presentation: 6/1/2024

Fasting blood glucose and hemoglobin a1c: measures of insulin sensitivity?

Measures used in clinical practice should be indicative of health or disease. Fasting blood glucose and hemoglobin a1c are used routinely in clinical practice to diagnose diabetes but the utility of fasting blood glucose and hemoglobin a1c as measures of tissue sensitivity to insulin is unreliable at best

Intermittent fasting for systemic triglyceride metabolic reprogramming (IFAST): Design and methods of a prospective, randomized, controlled trial

BackgroundCaloric restriction prolongs lifespan in model organisms and improves metrics of aging-related diseases in humans, but daily compliance is challenging. Intermittent fasting improves metrics of lipid and glucose metabolism in the setting of weight loss but whether these metrics are improved independent of weight loss is not known. MethodsWe seek to address this gap with IFAST, a single-center, three-arm, prospective, randomized, controlled clinical trial. Eligible study participants are adults with no chronic medical conditions beyond prediabetes or overweight but who are at high risk for type 2 diabetes mellitus (T2D), defined as having a history of gestational diabetes or a first-degree relative with T2D. Participants will be randomized in a 1:2:2 schema to either a control group, a fasting group, or a fasting/weight maintenance group. The fasting groups will complete a 24-h fast one day per week for 12 weeks. The key mechanistic endpoint is change in triglyceride composition (defined by carbon content and degree of saturation) as measured by longitudinal metabolomics. The key safety endpoint is percent change from baseline in bone volume fraction (BV/TV; high-resolution peripheral quantitative CT) at the radius in the fasting group. Secondary endpoints include measures of insulin sensitivity (hyperinsulinemic-euglycemic clamp), clinical lipid profiling, systemic inflammation markers, hunger assessment, bone density, and bone microarchitecture with high-resolution peripheral quantitative CT. ConclusionIFAST will investigate intrinsic metabolic benefits of intermittent fasting beyond weight loss. Trial registrationClinicalTrials.gov ID NCT05722873.

Low muscle mass is associated with low insulin sensitivity, impaired pancreatic β cell function, and high glucose excursion in nondiabetic nonobese Japanese women

AimWe tested whether skeletal muscle mass is associated with insulin sensitivity, pancreatic β-cell function, and postglucose glycemia. MethodsAppendicular skeletal muscle mass (ASM) (relative to body size, %ASM) by DXA, surrogate measures of insulin sensitivity, insulin secretion and the disposition index (insulin sensitivity adjusted insulin secretion: a product of the insulinogenic index and Matsuda insulin sensitivity index) inferred from serum insulin kinetics during a 75 g oral glucose tolerance test (OGTT) were evaluated in 168 young and 65 middle-aged women, whose BMI averaged <23.0 kg/m2 and HbA1c ≦ 5.5 %. ResultsIn two groups of women, %ASM was associated negatively with homeostasis model assessment insulin resistance (HOMA-IR) and 2-h insulin (both p < 0.01 or less). In middle-aged women not in young women, %ASM was associated inversely with the Matsuda index (p < 0.001). In middle-aged women only, it also showed a positive association with the disposition index (p = 0.02) and inverse associations with 1-h and 2-h glucose (both p < 0.01) and area under the glucose concentration curve during OGTT (p = 0.006). On multivariate linear regression analyses, 2-h insulin emerged as a determinant of %ASM independently of HOMA-IR in young women (standardized β: 0.287, p < 0.001, R2 = 0.077). In middle-aged women, the Matsuda index emerged as a determinant of %ASM (standardized β: 0.476, p < 0.001) independently of HOMA-IR, log ODI and AUCg and explained 21.3 % of %ASM variability. Post-glucose glycemia and AUCg were higher and log ODI was lower in middle-aged women with low compared with high %ASM. ConclusionLow skeletal muscle mass (relative to body size) was associated with low insulin sensitivity in young and middle-aged Japanese women who were neither obese nor diabetic. Middle-aged women with low muscle mass had low disposition index, an early marker of inadequate pancreatic β-cell compensation, and hence high glucose excursion. Low skeletal muscle mass may be associated with the development of type 2 diabetes at a much lower BMI in Japanese people.

Sex-specific role of high-fat diet and stress on behavior, energy metabolism, and the ventromedial hypothalamus

BackgroundScientific evidence highlights the influence of biological sex on the relationship between stress and metabolic dysfunctions. However, there is limited understanding of how diet and stress concurrently contribute to metabolic dysregulation in both males and females. Our study aimed to investigate the combined effects of high-fat diet (HFD) induced obesity and repeated stress on fear-related behaviors, metabolic, immune, and hypothalamic outcomes in male and female mice.MethodsTo investigate this, we used a highly reliable rodent behavioral model that faithfully recapitulates key aspects of post-traumatic stress disorder (PTSD)-like fear. We subjected mice to footshock stressor followed by a weekly singular footshock stressor or no stressor for 14 weeks while on either an HFD or chow diet. At weeks 10 and 14 we conducted glucose tolerance and insulin sensitivity measurements. Additionally, we placed the mice in metabolic chambers to perform indirect calorimetric measurements. Finally, we collected brain and peripheral tissues for cellular analysis.ResultsWe observed that HFD-induced obesity disrupted fear memory extinction, increased glucose intolerance, and affected energy expenditure specifically in male mice. Conversely, female mice on HFD exhibited reduced respiratory exchange ratio (RER), and a significant defect in glucose tolerance only when subjected to repeated stress. Furthermore, the combination of repeated stress and HFD led to sex-specific alterations in proinflammatory markers and hematopoietic stem cells across various peripheral metabolic tissues. Single-nuclei RNA sequencing (snRNAseq) analysis of the ventromedial hypothalamus (VMH) revealed microglial activation in female mice on HFD, while male mice on HFD exhibited astrocytic activation under repeated stress.ConclusionsOverall, our findings provide insights into complex interplay between repeated stress, high-fat diet regimen, and their cumulative effects on health, including their potential contribution to the development of PTSD-like stress and metabolic dysfunctions, emphasizing the need for further research to fully understand these interconnected pathways and their implications for health.

Intra-Individual Variations in How Insulin Sensitivity Responds to Long-Term Exercise: Predictions by Machine Learning Based on Large-Scale Serum Proteomics.

Physical activity is effective for preventing and treating type 2 diabetes, but some individuals do not achieve metabolic benefits from exercise ("non-responders"). We investigated non-responders in terms of insulin sensitivity changes following a 12-week supervised strength and endurance exercise program. We used a hyperinsulinaemic euglycaemic clamp to measure insulin sensitivity among 26 men aged 40-65, categorizing them into non-responders or responders based on their insulin sensitivity change scores. The exercise regimen included VO2max, muscle strength, whole-body MRI scans, muscle and fat biopsies, and serum samples. mRNA sequencing was performed on biopsies and Olink proteomics on serum samples. Non-responders showed more visceral and intramuscular fat and signs of dyslipidaemia and low-grade inflammation at baseline and did not improve in insulin sensitivity following exercise, although they showed gains in VO2max and muscle strength. Impaired IL6-JAK-STAT3 signalling in non-responders was suggested by serum proteomics analysis, and a baseline serum proteomic machine learning (ML) algorithm predicted insulin sensitivity responses with high accuracy, validated across two independent exercise cohorts. The ML model identified 30 serum proteins that could forecast exercise-induced insulin sensitivity changes.

PREX proteins level correlation with insulin resistance markers and lipid profile in obese and overweight non-diabetic patients

Metabolic dysregulation and obesity are associated with many metabolic alterations, including impairment of insulin sensitivity and dyslipidemia. Recent studies highlight the key role of phosphatidylinositol 3,4,5-triphosphate-dependent Rac exchange proteins (PREX proteins) in the pathogenesis of obesity, advocating further elucidation of their potential therapeutic implications. The present study aimed to estimate the serum level of PREX proteins and its potential association with insulin resistance markers and plasma lipids level in obese and overweight non-diabetic patients. The study included 30 persons classified as obese, 30 as overweight, and 30 healthy individuals of similar age and gender. The levels of PREX1 and PREX2 were measured using ELISA kits, insulin, fasting glucose, glycosylated hemoglobin and total lipid profile were determined using appropriate photometric kits. HOMA-IR was used as a measure of insulin sensitivity. According to the obtained results, obese non-diabetic patients had higher serum PREX1 level compared to both overweight and normal-weight individuals. PREX1 correlated positively with the markers of insulin resistance and dyslipidemia. PREX2 level was shown to be lower both in obese compared to overweight patients and in overweight compared to normal-weight individuals. PREX2 correlated negatively with the markers of insulin resistance but not with the markers of dyslipidemia. Keywords: dyslipidemia, insulin resistance, obesity, overweight, PREX proteins

Metabolic profiling of galectin-1 and galectin-3: a cross-sectional, multi-omics, association study

ObjectivesExperimental studies indicate a role for galectin-1 and galectin-3 in metabolic disease, but clinical evidence from larger populations is limited.MethodsWe measured circulating levels of galectin-1 and galectin-3 in the Prospective investigation of Obesity, Energy and Metabolism (POEM) study, participants (n = 502, all aged 50 years) and characterized the individual association profiles with metabolic markers, including clinical measures, metabolomics, adipose tissue distribution (Imiomics) and proteomics.ResultsGalectin-1 and galectin-3 were associated with fatty acids, lipoproteins and triglycerides including lipid measurements in the metabolomics analysis adjusted for body mass index (BMI). Galectin-1 was associated with several measurements of adiposity, insulin secretion and insulin sensitivity, while galectin-3 was associated with triglyceride-glucose index (TyG) and fasting insulin levels. Both galectins were associated with inflammatory pathways and fatty acid binding protein (FABP)4 and -5-regulated triglyceride metabolic pathways. Galectin-1 was also associated with several proteins related to adipose tissue differentiation.ConclusionsThe association profiles for galectin-1 and galectin-3 indicate overlapping metabolic effects in humans, while the distinctly different associations seen with fat mass, fat distribution, and adipose tissue differentiation markers may suggest a functional role of galectin-1 in obesity.

Abstract PO2-08-10: Effect of 6 months of bazedoxifene + conjugated estrogens on body composition and insulin resistance

Abstract Menopause transition is often marked by an acceleration of visceral fat accumulation. Excess visceral fat is associated with insulin resistance and increased risk for breast cancer as well as heart disease and diabetes. We measured change in body composition (via iDXA), fasting insulin and glucose as part of an ongoing, Phase IIB trial (NCT04821141) of 6 months of bazedoxifene (BZA) + conjugated estrogen (CE) vs control with primary endpoints of change in mammographic density and breast tissue Ki-67. Participants are women ages 45-60 with vasomotor symptoms at increased risk for development of breast cancer. Methods: Visceral and total fat, lean, and total mass, were measured with iDXA (GE CoreScan™). Fasting plasma was assayed same day as drawn for total insulin using a chemiluminescence assay and glucose using a hexokinase method. Values generated were used to calculate HOMA IR (as a measure of insulin resistance) using the formula insulin µl/ml x glucose mg/dl/405. HOMA %S was calculated as 1/HOMA IR X100 as a measure of insulin sensitivity. Optimal HOMA IR is considered as ≤1; HOMA IR &amp;gt;1.5 is considered abnormal with &amp;gt;2.0 as evidence of insulin resistance. Optimal HOMA %S is 100%. Results: 24 women (12 BZA+CE, 12 Control) have completed baseline and 6-month body composition and insulin resistance assessments. Women randomized to BZA+CE were more likely to experience reduction in insulin resistance and improved insulin sensitivity despite a small weight gain over the initial 6 months. 7/12 randomized to BZA+CE had ≥15% reduction in HOMA IR vs only 2/12 controls. Three participants had HOMA IR &amp;gt;2 at baseline. Of these, one was randomized to BZA+CE and had a normal HOMA IR value at 6 months. The remaining two women were in the control group and saw no improvement in HOMA IR at 6 months. In addition, one woman randomized to control with normal HOMA-IR at baseline had HOMA IR &amp;gt; 2 at 6 months. Next Steps: The improvements in insulin resistance parameters with BZA+CE are similar to those observed in our rodent studies, supporting this combination as promising for use in breast cancer risk reduction in women with vasomotor symptoms at high-risk for metabolic disease. Citation Format: Carol Fabian, Adrian Zelenchuk, Kandy Powers, Amy Kreutzjans, Krystal Pittman, Bill Hendry, Christy Altman, Erin Giles, Katherine L. Cook, Stephen Hursting, Bruce Kimler. Effect of 6 months of bazedoxifene + conjugated estrogens on body composition and insulin resistance [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-08-10.

The Reproducibility and Reliability of Insulin Sensitivity and Secretion Indices in Children and Adolescents.

Insulin sensitivity and secretion indices can be useful tools in understanding insulin homeostasis in children at risk for diabetes. There have been few studies examining the reproducibility of these measures in pediatrics. To determine whether fasting or oral glucose tolerance test (OGTT)-derived insulin measures would be more reproducible and whether there would be differences based on weight, sex, race, and pubertal status. Observational study. Clinical research unit. Two hundred fifty-seven overweight/obese (BMI ≥ 85th%, n = 186) and normal weight (BMI < 85th%, n = 71) children without diabetes between ages of 8 and 17 were included in the study. OGTT tests performed in study participants at two separate visits within a 3-week period. We performed two formal oral glucose tolerance tests within a 3-week period. The reproducibility of fasting measures was compared with OGTT-derived measures by weight categories and compared by weight, sex, race, and pubertal status. Comparisons were made between the correlation coefficients of fasting vs. OGTT-derived measures and between normal weight vs. obese/overweight participants, male vs. female, White vs. Black, and pre- vs. post-midpubertal. Intraclass correlation coefficients were calculated for each comparison as well. For insulin sensitivity, the OGTT-derived measure was more reproducible than the fasting measures. There were no significant differences in reproducibility in the overweight/obese population compared to the normal weight population nor by sex, race, or pubertal status. Nonfasting insulin sensitivity measures are more reproducible than fasting insulin sensitivity measures, regardless of weight category. Insulin secretion measures have poor reproducibility overall. Weight status, sex, race, and midpubertal stage do not impact the reproducibility of insulin sensitivity and secretion measures.

Inhibitory Regulation of FOXO1 in PPARδ Expression Drives Mitochondrial Dysfunction and Insulin Resistance.

Forkhead box protein O1 (FoxO1) regulates muscle growth, but the metabolic role of FoxO1 in skeletal muscle and its mechanisms remain unclear. To explore the metabolic role of FoxO1 in skeletal muscle, we generated skeletal muscle-specific FoxO1 inducible knockout (mFoxO1 iKO) mice and fed them a high-fat diet to induce obesity. We measured insulin sensitivity, fatty acid oxidation, mitochondrial function, and exercise capacity in obese mFoxO1 iKO mice, and assessed the correlation between FoxO1 and mitochondrial-related protein in the skeletal muscle of diabetic patients. Obese mFoxO1 iKO mice exhibited improved mitochondrial respiratory capacity, which was followed by attenuated insulin resistance, enhanced fatty acid oxidation, and improved skeletal muscle exercise capacity. Transcriptional inhibition of FoxO1 in peroxisome proliferator-activated receptor δ (PPARδ) expression was confirmed in skeletal muscle and deletion of PPARδ abolished the beneficial effects of FoxO1 deficiency. FoxO1 protein levels were higher in the skeletal muscle of diabetic patients and negatively correlated with PPARδ and electron transport chain protein levels. These findings highlight FoxO1 as a new repressor in PPARδ gene expression in skeletal muscle and suggest that FoxO1 links insulin resistance and mitochondrial dysfunction in skeletal muscle via PPARδ.

Leveraging continuous glucose monitoring for personalized modeling of insulin-regulated glucose metabolism

Continuous glucose monitoring (CGM) is a promising, minimally invasive alternative to plasma glucose measurements for calibrating physiology-based mathematical models of insulin-regulated glucose metabolism, reducing the reliance on in-clinic measurements. However, the use of CGM glucose, particularly in combination with insulin measurements, to develop personalized models of glucose regulation remains unexplored. Here, we simultaneously measured interstitial glucose concentrations using CGM as well as plasma glucose and insulin concentrations during an oral glucose tolerance test (OGTT) in individuals with overweight or obesity to calibrate personalized models of glucose-insulin dynamics. We compared the use of interstitial glucose with plasma glucose in model calibration, and evaluated the effects on model fit, identifiability, and model parameters’ association with clinically relevant metabolic indicators. Models calibrated on both plasma and interstitial glucose resulted in good model fit, and the parameter estimates associated with metabolic indicators such as insulin sensitivity measures in both cases. Moreover, practical identifiability of model parameters was improved in models estimated on CGM glucose compared to plasma glucose. Together these results suggest that CGM glucose may be considered as a minimally invasive alternative to plasma glucose measurements in model calibration to quantify the dynamics of glucose regulation.

Growth Hormone Mediators and Glycemic Control in Youths With Type 2 Diabetes

Youth-onset type 2 diabetes (T2D) has a more aggressive phenotype than adult-onset T2D, including rapid loss of glycemic control and increased complication risk. To identify associations of growth hormone mediators with glycemic failure, beta cell function, and insulin sensitivity in youth-onset T2D. This post hoc secondary analysis of the Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) randomized clinical trial, which enrolled participants from July 2004 to February 2009, included 398 participants from 15 university-affiliated medical centers with available plasma samples from baseline and 36 months. Participants were youths aged 10 to 17 years with a duration of T2D of less than 2 years who were randomized to metformin, metformin plus lifestyle intervention, or metformin plus rosiglitazone. Participants were followed up for a mean (SD) of 3.9 (1.5) years during the trial, ending in 2011. Statistical analysis was performed from August 2022 to November 2023. Plasma insulin-like growth factor-1 (IGF-1), growth hormone receptor (GHR), and insulin-like growth factor binding protein 1 (IGFBP-1). Main outcomes were (1) loss of glycemic control during the TODAY study, defined as hemoglobin A1c (HbA1c) level of 8% or more for 6 months or inability to wean from insulin therapy, and (2) baseline and 36-month measures of glycemia (fasting glucose, HbA1c), insulin sensitivity (1/fasting C-peptide), high-molecular-weight adiponectin, and beta cell function (C-peptide index, C-peptide oral disposition index). This analysis included 398 participants (mean [SD] age, 13.9 [2.0] years; 248 girls [62%]; 166 Hispanic participants [42%]; 134 non-Hispanic Black participants [34%], and 84 non-Hispanic White participants [21%]). A greater increase in IGF-1 level between baseline and 36 months was associated with lower odds of glycemic failure (odds ratio [OR], 0.995 [95% CI, 0.991-0.997]; P < .001) and higher C-peptide index per 100-ng/mL increase in IGF-1 (β [SE], 0.015 [0.003]; P < .001). A greater increase in log2 GHR level between baseline and 36 months was associated with higher odds of glycemic failure (OR, 1.75 [95% CI, 1.05-2.99]; P = .04) and lower C-peptide index (β [SE], -0.02 [0.006]; P < .001). A greater increase in log2 IGFBP-1 level between baseline and 36 months was associated with higher odds of glycemic failure (OR, 1.37 [95% CI, 1.09-1.74]; P = .007) and higher high-molecular-weight adiponectin (β [SE], 431 [156]; P = .007). This study suggests that changes in plasma growth hormone mediators are associated with loss of glycemic control in youth-onset T2D, with IGF-1 associated with lower risk and GHR and IGFBP-1 associated with increased risk. ClinicalTrials.gov Identifier: NCT00081328.

Interactive calculator to estimate insulin sensitivity in type 1 diabetes.

The gold standard for measuring insulin sensitivity (IS) is the hyperinsulinemic-euglycemic clamp, a time, costly, and labor-intensive research tool. A low insulin sensitivity is associated with a complication-risk in type 1 diabetes. Various formulae using clinical data have been developed and correlated with measured IS in type 1 diabetes. We consolidated multiple formulae into an online calculator (bit.ly/estimated-GDR), enabling comparison of IS and its probability of IS <4.45 mg/kg/min (low) or >6.50 mg/kg/min (high), as measured in a validation set of clamps in 104 adults with type 1 diabetes. Insulin sensitivity calculations using different formulae varied significantly, with correlations (R2) ranging 0.005-0.87 with agreement in detecting low and high glucose disposal rates in the range 49-93% and 89-100%, respectively. We demonstrate that although the calculated IS varies between formulae, their interpretation remains consistent. Our free online calculator offers a user-friendly tool for individual IS calculations and also offers efficient batch processing of data for research.

Adipose knockout of H-ferritin improves energy metabolism in mice

ObjectiveFerritin, the principal iron storage protein, is essential to iron homeostasis. How iron homeostasis affects the adipose tissue is not well understood. We investigated the role of ferritin heavy chain in adipocytes in energy metabolism. MethodsWe generated adipocyte-specific ferritin heavy chain (Fth, also known as Fth1) knockout mice, herein referred to as FthAKO. These mice were analyzed for iron homeostasis, oxidative stress, mitochondrial biogenesis and activity, adaptive thermogenesis, insulin sensitivity, and metabolic measurements. Mouse embryonic fibroblasts and primary mouse adipocytes were used for in vitro experiments. ResultsIn FthAKO mice, the adipose iron homeostasis was disrupted, accompanied by elevated expression of adipokines, dramatically induced heme oxygenase 1(Hmox1) expression, and a notable decrease in the mitochondrial ROS level. Cytosolic ROS elevation in the adipose tissue of FthAKO mice was very mild, and we only observed this in the brown adipose tissue (BAT) but not in the white adipose tissue (WAT). FthAKO mice presented an altered metabolic profile and showed increased insulin sensitivity, glucose tolerance, and improved adaptive thermogenesis. Interestingly, loss of ferritin resulted in enhanced mitochondrial respiration capacity and a preference for lipid metabolism. ConclusionsThese findings indicate that ferritin in adipocytes is indispensable to intracellular iron homeostasis and regulates systemic lipid and glucose metabolism.