l-arginine infusion decreases plasma total homocysteine concentrations through increased nitric oxide production and decreased oxidative status in Type II diabetic patients
- 1 August 2002
- journal article
- clinical trial
- Published by Springer Nature in Diabetologia
- Vol. 45 (8) , 1120-1127
- https://doi.org/10.1007/s00125-002-0854-1
Abstract
Aims/hypothesis. Hyperhomocysteinaemia increases cardiovascular risk in Type II (non-insulin-dependent) diabetes mellitus by augmenting oxidative stress and reducing nitric oxide availability. In vitro, nitric oxide decreases homocysteine by its conversion to the vasodilative and antioxidant compound S-nitrosohomocysteine. We investigated whether or not changes in nitric oxide availability decrease homocysteine concentrations in vivo. Methods. The study group consisted of 20 normotensive, normolipidaemic, non-atherosclerotic Type II diabetic patients in good metabolic control (16 men, 51.2±1.4 years) and 15 healthy subjects (12 men, 48.1±1.5 years). Circulating concentrations of homocysteine, nitrite+nitrate and sulphydryl groups, a marker of oxidative stress, were assessed at baseline and then 5′, 10′, 30′ and 60′ after the intravenous infusion of either L-arginine (3 g in 10 ml saline), the nitric oxide precursor, or vehicle according to a double-blind cross-over randomized protocol. Results. At baseline diabetic patients showed lower plasma sulphydryl group concentrations (491.8±16.9 vs 551.3±21.0 µmol/l, pppp≤0.05) decreased (peak at 5′ and 30′, respectively) whereas nitric oxide and sulphydryl group concentrations (p≤0.003) increased (peak at 10′ and 30′, respectively) in the patients and control subjects. Conclusion/interpretation. Acute L-arginine infusion in both Type II diabetic patients and healthy subjects decreases plasma total homocysteine concentrations, counteract oxidative stress and increases the availability of nitric oxide.Keywords
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