Effects of valsartan and 17 beta-estradiol on the oxidation of low-density lipoprotein in vitro

Abstract

Background: The 'sartans' are antagonists of the angiotensin type 1 (AT1) receptor that are mainly used for treatment of hypertension. Little is known about AT1-independent effects of these substances and interactions with other drugs used for prevention of cardiovascular diseases. Postmenopausal estradiol-replacement therapy has been shown to exert beneficial antiathero-sclerotic properties by inhibiting oxidation of low-density lipoprotein (LDL).

Objective: In the present study, the effects of valsartan alone and in combination with 17 beta-estradiol on the oxidation of isolated human LDL were investigated.

Methods: Oxidation of LDL, which was triggered by copper (II) chloride, was monitored spectrometrically at 234 nm. The test substances were added in vitro.

Results: Valsartan alone increased the duration of resistance of LDL to oxidation by 75.3 +/- 5.7 min at 5 mumol/l and by 138.2 +/- 8.1 min at 10 mumol/l. 17 beta-estradiol alone delayed the onset of oxidation of LDL by 75.7 +/- 5.1 min at 1 mumol/l. With the combination of 5 and 10 mumol/l valsartan with 1 mumol/l estradiol the time to onset of oxidation of LDL was increased by 142.8 +/- 4.9 and 215.3 +/- 6.9 min, respectively.

Conclusions: There has been demonstrated an antioxidative effect of valsartan that was additive to that of 17 beta-estradiol. Thus this combination has the potential to be useful in the treatment of postmenopausal women with hypertension.