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Hyperhomocysteinemia and atherothrombotic disease
S C de Jong1, M van den Berg, J A Rauwerda
1Institute for Cardiovascular Research, Vrije Universiteit, Amsterdam, The Netherlands.
Insights
High homocysteine levels (hyperhomocysteinemia) contribute to vascular disease. Understanding how homocysteine damages blood vessels is crucial for developing effective treatments for atherothrombotic conditions.
Area of Science:
- Cardiovascular Science
- Vascular Biology
- Metabolic Disorders
Background:
- Hyperhomocysteinemia is a known risk factor for atherothrombotic diseases.
- The precise mechanisms linking homocysteine to atherosclerosis and thrombosis remain unclear.
- Limited human data exist on arterial histology in homocystinuria and mild hyperhomocysteinemia.
Purpose of the Study:
- To investigate the impact of hyperhomocysteinemia on vascular endothelium function and smooth muscle cell proliferation.
- To explore the role of homocysteine in atherogenesis and thrombosis.
- To assess endothelial dysfunction in hyperhomocysteinemic patients and healthy individuals.
Main Methods:
- Review of in vitro, animal, and human studies on hyperhomocysteinemia.
- Analysis of endothelial function (vasodilation, antithrombotic properties) in hyperhomocysteinemic subjects.
- Examination of vascular smooth muscle cell proliferation.
Main Results:
- Hyperhomocysteinemia induces vascular endothelial dysfunction, impairing vasodilation and antithrombotic properties.
- Endothelial antithrombotic properties are more severely impaired in hyperhomocysteinemic vascular patients compared to normohomocysteinemic patients.
- Clinically healthy hyperhomocysteinemic subjects show impaired endothelium-dependent vasodilation but normal endothelial antithrombotic properties.
Conclusions:
- Hyperhomocysteinemia significantly contributes to atherothrombotic disease through endothelial dysfunction and smooth muscle cell proliferation.
- Oxidative damage is a potential mechanism requiring further human investigation.
- Homocysteine-lowering therapies warrant further study in both vascular patients and healthy individuals to elucidate causal mechanisms.
Abstract:
Hyperhomocysteinemia is an independent risk factor for atherothrombotic disease. The mechanism by which homocysteine induces atherosclerosis and thrombosis is not fully understood. Data on arterial histology in humans with homocystinuria and mild hyperhomocysteinemia are limited. In vitro studies as well as studies in animals and humans indicate that hyperhomocysteinemia induces dysfunction of the vascular endothelium, with loss of endothelium-dependent vasodilation and endothelial antithrombotic properties, and proliferation of vascular smooth muscle cells, which are key processes in current models of atherogenesis and thrombosis. One of the hypotheses is that homocysteine can lead to cellular dysfunction through a mechanism involving oxidative damage but future studies in humans are needed to confirm this. Studies in hyperhomocysteinemic vascular patients have shown that endothelial antithrombotic properties appear to be more severely impaired than in similar patients with normohomocysteinemia. Furthermore, impaired endothelium-dependent vasodilation has been observed in clinically healthy hyperhomocysteinemic subjects in whom no abnormalities were found in endothelial antithrombotic properties. Future studies involving homocysteine-lowering treatment in hyperhomocysteinemic patients with vascular disease and in clinically healthy hyperhomocysteinemic subjects are necessary to investigate the mechanisms by which homocysteine causes atherothrombotic disorders in humans.