Relationship between insulin resistance and inflammatory markers and anti-inflammatory effect of losartan in patients with type 2 diabetes and hypertension

BackgroundIt is now well established that vascular inflammation and endothelial dysfunction associated with cardiovascular diseases contributes to insulin resistance.MethodsWe investigated the relationship between the homeostasis model assessment-insulin resistance index (HOMA-R) and various serum inflammatory markers and the effect of losartan on serum concentrations of these markers in patients with type 2 diabetes and hypertension. The patients were divided into 2 groups according to the value of HOMA-R with 60 patients with values = 2.4 in Group A and 44 patients with values > 2.5 in Group B. The variables were measured at baseline and after 6 months of treatment with losartan (50 mg/day).ResultsThe HOMA-R concentrations were positively related to TNF-α (r = 0.336, P < 0.01) and inversely related to adiponectin (r = − 0.405, P < 0.01) and extracellular-superoxide dismutase (EC-SOD) (r = − 0.452, P < 0.01). Stepwise multiple regression analysis showed a significant relationship between HOMA-R and adiponectin (F = 8.74) and EC-SOD (F = 14.39). In Group B, losartan treatment significantly increased the serum concentrations of EC-SOD and adiponectin and decreased TNF-α and HOMA-R.ConclusionSerum EC-SOD concentrations may be a sensitive biochemical marker of insulin resistance in patients with type 2 diabetes and hypertension and that losartan improves insulin sensitivity by increasing EC-SOD and adiponectin production and decreasing TNF-α production.