Subcutaneous adipose tissue imaging of human obesity reveals two types of adipocyte membranes: Insulin-responsive and -nonresponsive.

In adipose tissue, resistance to insulin's ability to increase glucose uptake can be induced by multiple factors, including obesity. Impaired insulin action may take place at different spatial loci at the cellular or subcellular level. To begin to understand the spatial response to insulin in human subcutaneous adipose tissue (hSAT), we developed a quantitative imaging method for activation of a major signaling node in the glucoregulatory insulin signaling pathway. After treatment with insulin or control media, biopsied tissues were immunostained for Akt phosphorylation at Thr-308/9 (pAkt) and then imaged by confocal fluorescence microscopy automated to collect a large grid of high resolution fields. In hSAT from 40 men and women with obesity, substantial heterogeneity of pAkt densities in adipocyte membranes were quantified in each image mosaic using a spatial unit of at least twice the size of the point spread function. Statistical analysis of the distribution of pAkt spatial units was best fit as the weighted sum of two separate distributions, corresponding to either a low or high pAkt density. A "high pAkt fraction" metric was calculated from the fraction of high pAkt distributed units over the total units. Importantly, upon insulin stimulation, tissues from the same biopsy showed either a minimal or a substantial change in the high pAkt fraction. Further supporting a two-state response to insulin stimulation, subjects with similar insulin sensitivity indices are also segregated into either of two clusters identified by the amount of membrane-localized pAkt.

Effects of colchicine in adults with metabolic syndrome: A pilot randomized controlled trial.

AIM: To evaluate the efficacy and safety of colchicine for improving metabolic and inflammatory outcomes in people with obesity and metabolic syndrome (MetS). MATERIALS AND METHODS: Adults with obesity and MetS, but who did not have diabetes, were randomized to colchicine 0.6 mg or placebo capsules twice daily for 3 months. The primary outcome was change in insulin sensitivity (SI ) as estimated by insulin-modified frequently sampled intravenous glucose tolerance tests. Secondary outcomes included changes in other metabolic variables and inflammatory markers. RESULTS: Of 40 participants randomized (21 colchicine, 19 placebo), 37 completed the trial. Compared with placebo, colchicine significantly reduced C-reactive protein (P <0.005), erythrocyte sedimentation rate (P <0.01), white blood cell count (P <0.005), and absolute neutrophil count (P <0.001). Change in SI was not significantly different between colchicine and placebo arms (difference: +0.21 × 10-5 ; CI -1.70 to +2.13 × 10-5 min-1 mU-1 mL; P = 0.82). However, changes in some secondary outcomes, including homeostatic model assessment of insulin resistance (P = 0.0499), fasting insulin (P = 0.07) and glucose effectiveness (P = 0.08), suggested metabolic improvements in the colchicine versus placebo group. Adverse events were generally mild and similar in both groups. CONCLUSIONS: This pilot study found colchicine significantly improved obesity-associated inflammatory variables and showed a good safety profile among adults with obesity and MetS who did not have diabetes. These results suggest a larger, adequately powered study should be conducted to determine whether colchicine improves insulin resistance and other measures of metabolic health in at-risk individuals.