Related Experiment Videos
[Hyperhomocysteinemia--a risk factor for development of occlusive vascular diseases]
Mirjana Milosević-Tosić1, Jela Borota
1Institut medicinskih sluzbi Zavod za biohemiju, Klinicki centar, Novi Sad.
Insights
High homocysteine levels (hyperhomocysteinemia) are a significant risk factor for vascular diseases like heart attack and stroke. Supplementing with B vitamins may help lower homocysteine, but its impact on reducing cardiovascular risk needs further study.
Area of Science:
- Cardiovascular Medicine
- Biochemistry
- Vascular Biology
Context:
- Occlusive vascular diseases are a leading cause of mortality globally.
- While many risk factors are known, homocysteine is emerging as a critical, under-recognized factor.
- Hyperhomocysteinemia, elevated homocysteine levels, is linked to atherosclerosis and various vascular conditions.
Purpose:
- To review the role of homocysteine in the development of occlusive vascular diseases.
- To discuss the causes and mechanisms of hyperhomocysteinemia.
- To evaluate the potential of B-vitamin supplementation in managing this risk factor.
Summary:
- Homocysteine, an amino acid metabolite, is a significant risk factor for cerebrovascular (42%), peripheral vascular (28%), and coronary artery disease (30%).
- Elevated homocysteine levels increase the risk of myocardial infarction threefold and are associated with carotid artery stenosis and poor prognosis in coronary disease.
- Causes include genetic factors (enzyme deficiencies) and nutritional deficiencies (B12, folate, B6).
- Mechanisms involve endothelial dysfunction, altered coagulation, and oxidative stress, though precise pathways require further elucidation.
Impact:
- Establishes hyperhomocysteinemia as a key risk factor for occlusive vascular diseases.
- Highlights the potential therapeutic role of B-group vitamins in managing homocysteine levels.
- Suggests the need for further research to confirm the efficacy of homocysteine reduction in mitigating cardiovascular risk.
Introduction:
Occlusive vascular diseases take the first places on lists of diseases in general population today. In spite of this, all risk factors which contribute to development of these diseases are not yet known. Recent studies have shown that homocysteine plays a critical role in it and is established as a new risk factor. WHAT IS HOMOCYSTEINE?: Homocysteine is a sulfur containing amino acid formed in the metabolism of methionine. Reference values of homocysteine in circulation and different forms in plasma are described. HYPERHOMOCYSTEINEMIA--A RISK FACTOR: Homocysteine was associated with atherosclerosis and occlusive vascular disease in 1960s for the first time. Since then, many studies--prospective and retrospective, have confirmed the role of hyperhomocysteinemia as a risk factor in 42% of patients with cerebrovascular disease, 28% with peripheral vascular and 30% with coronary artery disease. The Physician's Health Study, a prospective study in which 15,000 male physicians took part, revealed that increase in homocysteine concentration of 1.7 mumol/l above normal values was associated by threefold higher risk for myocardial infarction. The risk for carotid artery stenosis also increases with elevation of homocysteine concentration. Hyperhomocysteinemia is associated with poor prognosis in patients with angiographically established coronary disease. Stroke, venous thromboembolism, and atherosclerosis in chronic renal failure are some of the complications of hyperhomocysteinemia.
Causes Of Hyperhomocysteinemia:
Hyperhomocysteinemia has numerous genetic and nongenetic etiologic factors. Cystathionine synthase deficiency, methylenetetrahydrofolate reductase deficiency and defects in the synthesis of cobalamin cofactors are genetically determined. Nutritional factors such as B12, folate or B6 vitamin deficiency, cofactors in homocysteine metabolism, lead to hyperhomocysteinemia.
Mechanisms Of Homocysteine Action:
Atherogenic propensity of homocysteine is related to endothelial dysfunction, blood thrombocyte aggregation changes in factors of coagulation. Oxidative stress is involved, but the exact mechanism is still unknown.
Conclusion:
Hyperhomocysteinemia is established as an important risk factor for occlusive vascular diseases. Reduction in homocysteine concentration can be achieved by supplementation of B-group vitamins, cofactors in homocysteione metabolism. Is it going to be effective in reducing cardiovascular risks remains to be seen.