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Published on: October 15, 2010
Endothelial dysfunction and atherothrombosis in mild hyperhomocysteinemia
Norbert Weiss1, Christiane Keller, Ulrich Hoffmann
1Medical Policlinic, Division of Angiology, University Hospital, Innenstadt, Munich, Germany. nweiss@medpoli.med.uni-muenchen.de
Insights
Mildly elevated homocysteine is a risk factor for vascular disease. Folic acid and vitamin B12 can lower homocysteine levels and improve endothelial function, potentially preventing atherothrombotic events.
Area of Science:
- Cardiovascular Science
- Metabolic Disease Research
- Vascular Biology
Background:
- Mildly elevated plasma homocysteine is an independent risk factor for atherothrombotic vascular disease.
- Hyperhomocysteinemia contributes to vascular disorders through endothelial dysfunction, including impaired vasoregulation and antithrombotic function.
- Homocysteine-induced oxidant stress reduces nitric oxide bioavailability, central to endothelial dysfunction.
Purpose of the Study:
- To investigate the role of homocysteine in atherothrombotic vascular disease.
- To explore the mechanisms of homocysteine-induced endothelial dysfunction.
- To evaluate the efficacy of folic acid and vitamin B12 supplementation in managing hyperhomocysteinemia and its vascular effects.
Main Methods:
- Review of existing literature on homocysteine and vascular disease.
- Analysis of molecular mechanisms linking homocysteine to endothelial dysfunction, including oxidant stress and nitric oxide pathways.
- Examination of studies on folic acid and vitamin B12 supplementation for homocysteine reduction and endothelial function improvement.
Main Results:
- Elevated homocysteine impairs endothelial function by increasing oxidant stress and decreasing nitric oxide bioavailability.
- Supplementation with folic acid and vitamin B12 effectively lowers plasma homocysteine levels.
- These supplements can reverse homocysteine-induced impairments in endothelium-dependent vasoreactivity.
Conclusions:
- Hyperhomocysteinemia contributes to atherothrombotic vascular disease via endothelial dysfunction.
- Folic acid and vitamin B12 supplementation show promise in mitigating these vascular risks.
- Further intervention trials are needed to confirm the role of homocysteine-lowering therapies in preventing atherothrombotic events.
Abstract:
Mildly elevated plasma homocysteine levels are an independent risk factor for atherothrombotic vascular disease in the coronary, cerebrovascular, and peripheral arterial circulation. Endothelial dysfunction as manifested by impaired endothelium-dependent regulation of vascular tone and blood flow, by increased recruitment and adhesion of circulating inflammatory cells to the endothelium, and by a loss of endothelial cell antithrombotic function contributes to the vascular disorders linked to hyperhomocysteinemia. Increased vascular oxidant stress through imbalanced thiol redox status and inhibition of important antioxidant enzymes by homocysteine results in decreased bioavailability of the endothelium-derived signaling molecule nitric oxide via oxidative inactivation. This plays a central role in the molecular mechanisms underlying the effects of homocysteine on endothelial function. Supplementation of folic acid and vitamin B12 has been demonstrated to be efficient in lowering mildly elevated plasma homocysteine levels and in reversing homocysteine-induced impairment of endothelium-dependent vasoreactivity. Results from ongoing intervention trials will determine whether homocysteine-lowering therapies contribute to the prevention and reduction of atherothrombotic vascular disease and may thereby provide support for the causal relationship between hyperhomocysteinemia and atherothrombosis.
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