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We recently showed that insulin increased ER stress in human adipose tissue. The effect of insulin resistance on ER stress is not known. It could be decreased, unchanged, or increased, depending on whether insulin regulates ER stress via the metabolic/phosphoinositide 3-kinase (PI3K) or alternate signaling pathways. To address this question, we examined effects of lipid-induced insulin resistance on insulin stimulation of ER stress. mRNAs of several ER stress markers were determined in fat biopsies obtained before and after 8-h hyperglycemic-hyperinsulinemic clamping in 13 normal subjects and in 6 chronically insulin-resistant patients with type 2 diabetes mellitus (T2DM). In normal subjects, hyperglycemia-hyperinsulinemia increased after/before mRNA ratios of several ER stress markers (determined by ER stress pathway array and by individual RT-PCR). Lipid infusion was associated with inhibition of the PI3K insulin-signaling pathway and with a decrease of hyperinsulinemia-induced ER stress responses. In chronically insulin-resistant patients with T2DM, hyperglycemic-hyperinsulinemia did not increase ER stress response marker mRNAs. In summary, insulin resistance, either produced by lipid infusions in normal subjects or chronically present in T2DM patients, was associated with decreased hyperinsulinemia-induced ER stress responses. This suggests, but does not prove, that these two phenomena were causally related.

Background In randomized controlled trials (RCTs), colesevelam HCI, added to other anti-diabetic therapy, reduced hemoglobin A1C by approximately 0.3% to 0.4% over 16- to 26-weeks compared with an increase of approximately 0.1% to 0.2% for placebo, for a placebo-adjusted treatment effect of approximately 0.5%. Evidence on real-world effectiveness is unknown. This retrospective cohort study examined A1C changes following colesevelam HCL initiation in patients with diabetes, regardless of concomitant anti-diabetic medication use. Methods 2000–2011 GE Centricity electronic medical records data were used to identify patients with type 2 diabetes mellitus (T2DM) aged 18 or older initiating colesevelam HCL. The sample was further restricted to uncontrolled patients with database activity ≥ 395 days before and after colesevelam HCL initiation, A1C > 7% during 90 days prior to starting colesevelam HCL, without prior use of bile acid sequestrants, and with at least one A1C result between 42 to 210 days after initiation. Three overlapping time intervals were created for A1C measurement, including 16-weeks, 26-weeks, and 52-weeks following therapy initiation. The last observed A1C lab measurement during each interval was used to define change from baseline. Mean change in A1C was examined using paired t-tests. Sensitivity analyses considered only patients who remained on colesevelam HCL through each respective measurement period, as well as the effect of concomitant diabetes medications. Results Of 1,709,393 patients in the GE database with T2DM, 1,747 met inclusion criteria. The cohort was 58% female, 38% age ≥ 65, and the majority was white. For the 16-week endpoint (N = 1,385), A1C dropped from a mean of 8.22% to 7.75% (mean change −0.47%; P