Cellular insulin resistance in Epstein-Barr virus-transformed lymphoblasts from young insulin-resistant Japanese men.

ABSTRACT

The metabolic syndrome is characterized by a blunted insulin-mediated glucose uptake in various cell types. We compared the glucose uptake characteristics of Epstein-Barr virus (EBV)-transformed lymphoblasts obtained from young men with vs without metabolic and cardiovascular evidence of metabolic syndrome. From a population of 218 men, 20- to 25-year-old, 10 men with a systolic blood pressure (BP) > or =130 mm Hg and family history of hypertension were assigned to a high BP (HBP) group, and 10 with a BP < or =110 mm Hg, and no family history of hypertension was assigned to a low BP (LBP) group. Multiple clinical and metabolic characteristics were examined in both groups and compared. Peripheral lymphocytes from HBP and LBP subjects were EBV-transformed, and the glucose transporter (Glut)-mediated glucose uptake from each group was compared in lymphoblasts. Body mass index, fasting glucose, immunoreactive insulin, insulin resistance index based on a homeostasis model assessment (HOMA-R), and total and low-density lipoprotein cholesterol were significantly higher in the HBP than the LBP subgroup (whole-body insulin resistance). Baseline Glut-mediated and Glut-mediated insulin-stimulated glucose uptake by lymphoblasts from the HBP group were significantly lower than by lymphoblasts from the LBP group (cellular insulin resistance). The net increment in Glut-mediated glucose uptake by insulin was inversely correlated with HOMA-R. In conclusion, cellular insulin resistance in EBV-transformed lymphoblasts is associated with young Japanese subjects with HBP. The net increment in Glut-mediated glucose uptake by insulin in lymphoblasts may be a useful intermediate phenotype to study genetic aspects of the metabolic syndrome.