Genetic Insulin Resistance Is a Potent Regulator of Gene Expression and Proliferation in Human iPS Cells

Insulin resistance is central to diabetes and metabolic syndrome. To define the consequences of genetic insulin resistance distinct from those secondary to cellular differentiation or in vivo regulation, we generated induced pluripotent stem cells (iPSCs) from individuals with insulin receptor mutations and age-appropriate control subjects and studied insulin signaling and gene expression compared with the fibroblasts from which they were derived. iPSCs from patients with genetic insulin resistance exhibited altered insulin signaling, paralleling that seen in the original fibroblasts. Insulin-stimulated expression of immediate early genes and proliferation were also potently reduced in insulin resistant iPSCs. Global gene expression analysis revealed marked differences in both insulin-resistant iPSCs and corresponding fibroblasts compared with control iPSCs and fibroblasts. Patterns of gene expression in patients with genetic insulin resistance were particularly distinct in the two cell types, indicating dependence on not only receptor activity but also the cellular context of the mutant insulin receptor. Thus, iPSCs provide a novel approach to define effects of genetically determined insulin resistance. This study demonstrates that effects of insulin resistance on gene expression are modified by cellular context and differentiation state. Moreover, altered insulin receptor signaling and insulin resistance can modify proliferation and function of pluripotent stem cell populations.     

Predicting Adherence to Medications Using Health Psychology Theories: A Systematic Review of 20 Years of Empirical Research

ObjectivesThis review sought to identify the empirical evidence for the application of models from sociocognitive theory, self-regulation theory, and social support theory at predicting patient adherence to medications.MethodsA systematic review of the published literature (1990–2010) using MEDLINE, EMBASE, Cochrane Library, CINAHL, and PsychINFO identified studies examining the application of health psychology theory to adherence to medication in adult patients. Two independent reviewers extracted data on medication, indication, study population, adherence measure, theory, model, survey instruments, and results. Heterogeneity in theoretical model specification and empirical investigation precluded a meta-analysis of data.ResultsOf 1756 unique records, 67 articles were included (sociocognitive = 35, self-regulation = 21, social support = 11). Adherence was most commonly measured by self-report (50 of 67). Synthesis of studies highlighted the significance (P ≤ 0.05) of self-efficacy (17 of 19), perceived barriers (11 of 17), perceived susceptibility (3 of 6), necessity beliefs (8 of 9), and medication concerns (7 of 8).ConclusionsThe results of this review provide a foundation for the development of theory-led adherence-enhancing interventions that could promote sustainable behavior change in clinical practice.