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 microg/mL at baseline to 11.1 +/- 6.2 microg/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 microg/mL at baseline to 6.6 +/- 4.4 microg/mL at 6 months (P < .01). In hypertensive patients with MS, the serum total adiponectin increased from 6.0 +/- 2.7 mug/mL at baseline to 6.7 +/- 3.3 microg/mL at 3 months and to 7.0 +/- 3.1 microg/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.