Strength training is more effective than aerobic exercise for improving glycaemic control and body composition in people with normal-weight type 2 diabetes: a randomised controlled trial.

AIMS/HYPOTHESIS: Type 2 diabetes in people in the healthy weight BMI category (<25 kg/m2), herein defined as 'normal-weight type 2 diabetes', is associated with sarcopenia (low muscle mass). Given this unique body composition, the optimal exercise regimen for this population is unknown. METHODS: We conducted a parallel-group RCT in individuals with type 2 diabetes (age 18-80 years, HbA1c 47.5-118.56 mmol/mol [6.5-13.0%]) and BMI <25 kg/m2). Participants were recruited in outpatient clinics or through advertisements and randomly assigned to a 9 month exercise programme of strength training alone (ST), aerobic training alone (AER) or both interventions combined (COMB). We used stratified block randomisation with a randomly selected block size. Researchers and caregivers were blinded to participants' treatment group; however, participants themselves were not. Exercise interventions were conducted at community-based fitness centres. The primary outcome was absolute change in HbA1c level within and across the three groups at 3, 6 and 9 months. Secondary outcomes included changes in body composition at 9 months. Per adherence to recommended exercise protocol (PP) analysis included participants who completed at least 50% of the sessions. RESULTS: Among 186 individuals (ST, n=63; AER, n=58; COMB, n=65) analysed, the median (IQR) age was 59 (53-66) years, 60% were men and 83% were Asian. The mean (SD) HbA1c level at baseline was 59.6 (13.1) mmol/mol (7.6% [1.2%]). In intention-to-treat analysis, the ST group showed a significant decrease in HbA1c levels (mean [95% CI] -0.44 percentage points [-0.78, -0.12], p=0.002), while no significant change was observed in either the COMB group (-0.35 percentage points, p=0.13) or the AER group (-0.24 percentage points, p=0.10). The ST group had a greater improvement in HbA1c levels than the AER group (p=0.01). Appendicular lean mass relative to fat mass increased only in the ST group (p=0.0008), which was an independent predictor of HbA1c change (beta coefficient -7.16, p=0.01). Similar results were observed in PP analysis. Only one adverse event, in the COMB group, was considered to be possibly associated with the exercise intervention. CONCLUSIONS/INTERPRETATION: In normal-weight type 2 diabetes, strength training was superior to aerobic training alone, while no significant difference was observed between strength training and combination training for HbA1c reduction. Increased lean mass relative to decreased fat mass was an independent predictor of reduction in HbA1c level. TRIAL REGISTRATION: ClinicalTrials.gov NCT02448498. FUNDING: This study was funded by the National Institutes of Health (NIH; R01DK081371).

Safety, efficacy and pharmacokinetics of repeat subcutaneous dosing of avexitide (exendin 9-39) for treatment of post-bariatric hypoglycaemia.

AIM: To evaluate the safety, efficacy and pharmacokinetics of repeat dosing of two formulations of subcutaneous (SC) avexitide (exendin 9-39) in patients with post-bariatric hypoglycaemia (PBH). METHODS: In this phase 2, multiple-ascending-dose study conducted at Stanford University, 19 women with PBH underwent a baseline oral glucose tolerance test (OGTT), with metabolic and symptomatic assessments. Fourteen were then sequentially assigned to receive one of four ascending-dose levels of twice-daily lyophilized (Lyo) avexitide by SC injection for 3 days. On the basis of safety, efficacy and tolerability, five additional participants then received a novel liquid formulation (Liq) of avexitide by SC injection at a fixed dose of 30 mg twice daily for 3 days. All 19 participants underwent a repeat OGTT on day 3 of dosing to quantify metabolic, symptomatic and pharmacokinetic responses. RESULTS: Treatment with Lyo avexitide reduced the magnitude of symptomatic hyperinsulinaemic hypoglycaemia at all dose levels, with dose-dependent improvements in glucose nadir, insulin peak and symptom score; doses ≥20 mg twice daily did not require glycaemic rescue (administered at glucose <2.8 mmol/L). Participants receiving Liq avexitide 30 mg twice daily did not require any glycaemic rescue, and on average achieved a 47% increase in glucose nadir, a 67% reduction in peak insulin, and a 47% reduction in overall symptom score. Equivalent doses of Liq versus Lyo avexitide yielded higher and more sustained plasma concentrations. Both formulations were well tolerated. CONCLUSIONS: In patients with PBH, twice-daily administration of SC avexitide effectively raised the glucose nadir and prevented severe hypoglycaemia requiring rescue intervention. Avexitide may represent a viable therapy for PBH.

Effectiveness of a Community-Based Structured Physical Activity Program for Adults With Type 2 Diabetes: A Randomized Clinical Trial.

Importance: The efficacy of physical activity interventions among individuals with type 2 diabetes has been established; however, practical approaches to translate and extend these findings into community settings have not been well explored. Objective: To test the effectiveness of providing varying frequencies of weekly structured exercise sessions to improve diabetes control. Design, Setting, and Participants: The IMPACT (Initiate and Maintain Physical Activity in Communities Trial) study was a controlled randomized clinical trial (randomization occurred from October 2016 to April 2019) that included a 6-month, structured exercise intervention either once or thrice weekly vs usual care (UC; advice only). The exercise intervention was conducted at community-based fitness centers. Follow-up visits were conducted in a university research clinic. Participants included adults with type 2 diabetes (hemoglobin A1c [HbA1c] 6.5%-13.0%, not taking insulin, and no precluding health issues). Data analysis was performed from January to April 2022. Interventions: A once-weekly structured exercise group, a thrice-weekly structured exercise group, or UC. Main Outcomes and Measures: The primary outcome was HbA1c at 6 months. Results: A total of 357 participants (143 women [40.1%]) with a mean (SD) age of 57.4 (11.1) years were randomized (119 each to the UC, once-weekly exercise, and thrice-weekly exercise groups). There was no significant difference in HbA1c change by study group in the intention-to-treat analysis at 6 months. Specifically, HbA1c changed by -0.23% (95% CI, -0.48% to 0.01%) in the thrice-weekly exercise group and by -0.16% (95% CI, -0.41% to 0.09%) in the once-weekly exercise group. A total of 62 participants (52.1%) in the once-weekly exercise group and 56 participants (47.1%) in the thrice-weekly exercise group were at least 50% adherent to the assigned structured exercise regimen and were included in the per-protocol analysis. Per-protocol analysis showed that HbA1c changed by -0.35% (95% CI, -0.60% to -0.10%; P = .005) at 3 months and by -0.38% (95% CI, -0.65% to -0.12%; P = .005) at 6 months in the thrice-weekly exercise group compared with UC. There was no significant decrease in HbA1c in the once-weekly exercise group. The exercise intervention was effective in improving self-reported minutes of metabolic equivalent tasks per week for participants in the thrice-weekly exercise group (both overall and per protocol). Conclusions and Relevance: Although the intervention was not effective in the intention-to-treat analysis, participants in the thrice-weekly exercise group who attended at least 50% of the sessions during the 6-month exercise intervention program improved HbA1c levels at 6 months. Future efforts should focus on improving adherence to thrice-weekly structured exercise programs to meet exercise guidelines. Trial Registration: ClinicalTrials.gov Identifier: NCT02061579.

Effect of rosiglitazone treatment on circulating vascular and inflammatory markers in insulin-resistant subjects.

Thiazolidinedione (TZD) compounds enhance insulin sensitivity and attenuate inflammation. The effect of the TZD compound, rosiglitazone (RSG) on both actions was evaluated in two groups of insulin-resistant subjects with minimal elevations of fasting plasma glucose (PG) concentration: group A (n=15, PG < 7.0 mmol/L) and group B (n=14, PG 7.0-8.3 mmol/L). Insulin action, quantified by the insulin suppression test, improved after three months of treatment in both groups, and concentrations of C-reactive protein, plasminogen activator inhibitor-1 and Eselectin all fell. Significant decreases in L-selectin and P-selectin were confined to group B, and concentrations of interleukin-6, intercellular adhesion molecule-1 and vascular cellular adhesion molecule-1 did not fall in either group. Significant relationships were not discerned between enhanced insulin sensitivity and related variables and decreases in inflammatory/vascular markers, suggesting that RSG-induced changes in the latter variables in insulin-resistant individuals might be at least partly independent of the effects of the drug on insulin action.

Circulating microRNA-320a and microRNA-486 predict thiazolidinedione response: Moving towards precision health for diabetes prevention.

INTRODUCTION: The aims of this study were to compare microRNA (miR) expression between individuals with and without insulin resistance and to determine whether miRs predict response to thiazolidinedione treatment. MATERIALS AND METHODS: In a sample of 93 healthy adults, insulin resistance was defined as steady state plasma glucose (SSPG)≥180 mg/dL and insulin sensitive as <120 mg/dL. Response to thiazolidinedione therapy was defined as ≥10% decrease in SSPG. We selected a panel of microRNAs based on prior evidence for a role in insulin or glucose metabolism. Fold change and Wilcoxon rank sum tests were calculated for the 25 miRs measured. RESULTS: At baseline, 81% (n=75) of participants were insulin resistant. Five miRs were differentially expressed between the insulin resistant and sensitive groups: miR-193b (1.45 fold change (FC)), miR-22-3p (1.15 FC), miR-320a (1.36 FC), miR-375 (0.59 FC), and miR-486 (1.21 FC) (all p<0.05). In the subset who were insulin resistant at baseline and received thiazolidinediones (n=47), 77% (n=36) showed improved insulin sensitivity. Six miRs were differentially expressed between responders compared to non-responders: miR-20b-5p (1.20 FC), miR-21-5p, (0.92 FC), miR-214-3p (1.13 FC), miR-22-3p (1.14 FC), miR-320a (0.98 FC), and miR-486-5p (1.25 FC) (all p<0.05). DISCUSSION: This study is the first to report miRs associated with response to a pharmacologic intervention for insulin resistance. MiR-320a and miR-486-5p identified responders to thiazolidinedione therapy among the insulin resistant group.

Relations between obesity, insulin resistance, and 25-hydroxyvitamin D.

BACKGROUND: Although low circulating 25-hydroxyvitamin D [25(OH)D] concentrations have been associated with insulin resistance and obesity, the relations between these 3 variables have not been completely resolved. OBJECTIVE: The objective was to compare circulating 25(OH)D concentrations in apparently healthy individuals who were matched for degree of obesity or insulin sensitivity. DESIGN: This was a case-control study in which 78 apparently healthy individuals were classified as being normal weight (NW) or obese (OB) on the basis of their BMI and as being insulin sensitive (IS) or insulin resistant (IR) on the basis of their steady state plasma glucose (SSPG) concentration during the insulin suppression test. RESULTS: Groups did not differ in terms of age, sex distribution, race, or mean (± SD) plasma 25(OH)D concentration. Values for 25(OH)D were 32 ± 10, 30 ± 10, and 28 ± 8 ng/mL in NW-IS, OB-IS, and OB-IR groups, respectively. These concentrations were essentially identical when comparing IR with IS subjects matched for BMI or when comparing OB with NW subjects matched for SSPG. Concentrations of 25(OH)D ≤ 30 ng/mL were somewhat more common in OB subjects than in NW subjects (54% compared with 35%), but SSPG concentrations were not different within either the IR or IS groups when subgroups with 25(OH)D concentrations ≤ 30 or > 30 ng/mL were compared. CONCLUSIONS: In 78 individuals, 47% of whom were vitamin D deficient or insufficient (≤ 30 ng/mL), 25(OH)D concentrations did not vary with differences in insulin sensitivity (SSPG concentration) when matched for BMI (OB-IR compared with OB-IS). Similarly, when matched for SSPG concentrations, plasma 25(OH)D concentrations were not different in NW or OB individuals (NW-IS compared with OB-IS).