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Homocysteine and coronary artery disease
K Robinson1, E Mayer, D W Jacobsen
1Department of Cardiology, Cleveland Clinic Foundation, OH 44195.
Insights
Homocystinuria, a disease causing high homocysteine levels, is linked to premature atherosclerosis and blood clots. Vitamin supplementation may help lower homocysteine, but its routine use for heart disease prevention needs more study.
Area of Science:
- Biochemistry
- Genetics
- Cardiovascular Medicine
Background:
- Homocystinuria is a rare genetic disorder characterized by elevated homocysteine levels.
- This condition is associated with early-onset and severe occlusive arterial disease.
- Milder hyperhomocysteinemia is increasingly recognized as an independent risk factor for coronary artery disease.
Purpose of the Study:
- To review the link between high homocysteine concentrations and arterial disease.
- To explore the metabolic pathways of homocysteine and causes of hyperhomocysteinemia.
- To discuss the potential adverse effects of homocysteine on vascular health.
Main Methods:
- Literature review of studies on homocystinuria, hyperhomocysteinemia, and cardiovascular disease.
- Analysis of the role of homocysteine metabolism and associated deficiencies (e.g., vitamins B6, B12, folic acid).
- Examination of evidence linking plasma homocysteine levels to occlusive arterial disease.
Main Results:
- Patients with homozygous homocystinuria frequently develop premature atherosclerosis and thromboembolism.
- Elevated homocysteine levels are significantly higher in individuals with occlusive arterial disease compared to controls.
- Potential contributing factors include vitamin deficiencies and genetic variations like cystathionine synthase deficiency.
Conclusions:
- High homocysteine concentrations likely contribute to atherosclerosis and thromboembolism in homocystinuria.
- Homocysteine may negatively impact platelets, clotting factors, and endothelial cells.
- Further research is needed to determine the routine measurement and therapeutic efficacy of lowering homocysteine in coronary artery disease patients.
Background:
Homocystinuria is a rare autosomal recessive disease complicated by early and aggressive occlusive arterial disease. This may be related to the grossly increased homocysteine concentrations seen in this disease. More recently, milder hyperhomocysteinemia has been proposed as an independent risk factor for coronary artery disease.
Summary:
Many patients with homozygous homocystinuria develop severe premature atherosclerosis and thromboembolism, probably caused by abnormally high concentrations of homocysteine. Homocysteine undergoes metabolism either by remethylation or transsulfuration, and deficiency or dysfunction of any of the substances that regulate these reactions may lead to hyperhomocysteinemia. Homocysteine may have adverse effects on platelets, clotting factors, and endothelial cells. Studies have demonstrated significantly higher plasma homocysteine levels in patients with occlusive arterial disease than in controls. The causes are not clearly understood but may include deficiency of vitamin B6, vitamin B12, and folic acid and heterozygosity for cystathionine synthase deficiency. Vitamin supplementation can lower plasma homocysteine levels.
Conclusions:
Whether measuring plasma homocysteine levels in patients with coronary artery disease should be routine and whether treating hyperhomocysteinemia in these patients may reduce the risk of coronary events remains to be determined.