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Homocysteine and endothelial dysfunction: a link with cardiovascular disease
1Wales Heart Research Institute, University of Wales College of Medicine, Heath Park, Cardiff.
Insights
High homocysteine levels may harm blood vessel function, potentially contributing to cardiovascular disease. Research suggests this damage involves oxidative stress and reactive oxygen species.
Area of Science:
- Cardiovascular Science
- Endothelial Biology
- Biochemistry
Background:
- The relationship between homocysteine and cardiovascular disease (CVD) remains unclear.
- Endothelial dysfunction, specifically impaired endothelium-independent vasodilation, is an early indicator of vascular disease.
Purpose of the Study:
- To investigate the role of homocysteine in endothelial dysfunction.
- To explore the potential mechanism involving reactive oxygen species.
Main Methods:
- Human studies involving methionine loading to elevate homocysteine and folate therapy to lower it.
- In vitro experiments exposing endothelial cells to high homocysteine concentrations.
- Assessing endothelial function and superoxide production.
Main Results:
- Methionine loading induced endothelial dysfunction in humans, while folate therapy improved it.
- High homocysteine concentrations caused endothelial dysfunction in vitro.
- This dysfunction was linked to increased superoxide production, which was reversible upon inhibition.
Conclusions:
- Homocysteine may induce vascular endothelial dysfunction.
- Reactive oxygen species likely mediate homocysteine-induced endothelial damage.
Abstract:
The nature of the link between homocysteine and cardiovascular disease has not yet been clearly established. Impaired endothelium-independent vasodilatation is an early feature of vascular disease. In human studies, methionine loading, which acutely elevates plasma homocysteine, induces endothelial dysfunction. Folate therapy, which lowers homocysteine, enhances endothelial function. This is consistent with, but not proof of, homocysteine toxicity to endothelium in vivo. Homocysteine, in high concentration, can induce endothelial dysfunction in vitro. This is accompanied by increased superoxide production, which when inhibited, restores normal endothelial function. These observations suggest that homocysteine may induce vascular endothelial dysfunction by a mechanism involving reactive oxygen species.