Effects of losartan on serum total and high–molecular weight adiponectin concentrations in hypertensive patients with metabolic syndrome

High–molecular weight (HMW) adiponectin may have the most biologic activity among several isoforms. We investigated long-term effects of losartan on serum concentrations of total and HMW adiponectin in hypertensive patients with metabolic syndrome (MS) by serial measurements over 6 months. Forty hypertensive patients first received 50 mg of losartan. Upward titration of the losartan dose was implemented to reach a target blood pressure of less than 140/90 mm Hg. Serum total adiponectin and HMW adiponectin were measured at study entry (baseline), the 3-month treatment time point, and the end of the 6-month period. Non-HMW adiponectin (ie, medium– and low–molecular weight adiponectin) was calculated as total adiponectin − HMW adiponectin. Diagnosis of MS was done by current standard criteria. In hypertensive patients without MS (n = 21), the serum total adiponectin increased from 9.8 ± 5.4 μg/mL at baseline to 11.1 ± 6.2 μg/mL at 6 months (P < .01). Furthermore, the serum total adiponectin was significantly higher at 6 months than at 3 months (P < .01). Serum HMW adiponectin also increased from 5.7 ± 3.9 μg/mL at baseline to 6.6 ± 4.4 μg/mL at 6 months (P < .01). In hypertensive patients with MS, the serum total adiponectin increased from 6.0 ± 2.7 μg/mL at baseline to 6.7 ± 3.3 μg/mL at 3 months and to 7.0 ± 3.1 μg/mL at 6 months (P < .01 for both). Furthermore, the serum HMW adiponectin concentration was significantly higher at 6 months than at 3 months (P < .001). However, the serum non-HMW adiponectin concentration did not change during treatment in either group. In conclusion, serum total and HMW adiponectin concentrations increase after 6 months of losartan treatment in hypertensive patients, irrespective of the presence or absence of MS.