Glucose inhibition of human fibroblast proliferation and response to growth factors is prevented by inhibitors of aldose reductase

Abstract

Diabetes mellitus is associated with premature senescence of cultured dermal fibroblasts. The present study investigated the effect of elevated glucose concentrations on cultured human fibroblasts from normal donors. Mean population doubling times, population doublings until senescence, saturation density at confluence (cells/cm2), tritiated thymidine incorporation, and response to platelet-derived growth factor (PDGF) were inhibited with the increasing glucose concentrations (11.0, 22, 44, or 55 mM glucose) (P less than 0.05). Replicative life span was markedly diminished by multiple passages in high glucose medium (5.5 mM glucose: 62.4 +/- 7.9 population doublings; 22 mM glucose: 22.8 +/- 3.4 population doublings: P less than 0.05). Aldose reductase activity was present in the cultured fibroblasts (3.9 +/- 0.5 nmol/min per mg protein), and inhibitors of aldose reductase, including sorbinil (10(-4) M--10(-6) M) and tolrestat (10(-6) M--10(-8) M), completely prevented glucose-mediated inhibition of fibroblast proliferation, restored the response to PDGF, and allowed a normal replicative life span. Myo-inositol (11 microM--5.5 mM) also reversed the adverse effects of glucose. These in vitro data demonstrate that elevated concentrations of glucose inhibit cell growth and promote premature senescence, effects which can be prevented with inhibitors of aldose reductase or supplemental myo-inositol. These aldose reductase-related effects may explain the impaired growth and premature senescence of cultured connective tissue from diabetic patients.