Dietary L-arginine supplementation normalizes platelet aggregation in hypercholesterolemic humans

Area of Science:

• Cardiovascular Science
• Biochemistry
• Pharmacology

Background:

• Hypercholesterolemia is associated with reduced nitric oxide activity and increased platelet aggregation.
• L-arginine supplementation restored nitric oxide activity and inhibited platelet aggregation in hypercholesterolemic rabbits.
• This effect is mediated by increased nitric oxide elaboration and intraplatelet cyclic guanosine monophosphate levels.

Purpose of the Study:

• To investigate the effect of long-term L-arginine supplementation on platelet reactivity in hypercholesterolemic humans.
• To determine if L-arginine enhances nitric oxide activity, thereby inhibiting platelet aggregation.
• To assess the duration of L-arginine's effects after discontinuation.

Main Methods:

• A double-blinded, randomized, placebo-controlled trial involving hypercholesterolemic patients.
• Patients received L-arginine hydrochloride (8.4 g/day) or placebo for 2 weeks.
• Platelet aggregation was measured using collagen-induced aggregometry at baseline, after treatment, and after washout periods.

Main Results:

• Hypercholesterolemic patients exhibited significantly higher platelet aggregability compared to normocholesterolemic controls.
• L-arginine treatment modestly reduced platelet reactivity, an effect that persisted for 2 weeks post-treatment.
• Platelet hyperaggregability returned after 16 weeks of L-arginine discontinuation; placebo showed no significant changes.

Conclusions:

• Dietary L-arginine supplementation can attenuate increased platelet reactivity in hypercholesterolemic patients.
• L-arginine enhances endogenous nitric oxide activity, inhibiting platelet aggregation, consistent with animal studies.
• Enhancing nitric oxide activity through L-arginine is a potential therapeutic strategy for cardiovascular conditions.