高同型半胱氨酸血症的发生机制及其病理生理学意义

Mechanism of hyperhomocysteinemia and its pathological significance

在过去的10年中,同型半胱氨酸(Hcy)被认为是心血管病及许多其他疾病明确的危险因素。Hcy由蛋氨酸通过多种步骤生物合成而来,再通过甲基化和转硫基途径重新生成蛋氨酸。高同型半胱氨酸血症(HHcy)是机体内Hcy过高的一种状态,其主要原因是Hcy代谢过程中相关的酶缺陷及辅助因子缺乏,其他原因包括蛋氨酸摄取过量、一些疾病影响及药物的副作用。HHcy是许多疾病如动脉粥样硬化、充血性心力衰竭、年龄相关性黄斑变性、阿尔茨海默病、听力丧失的触发因素。Hcy水平增高是许多疾病的独立原因或加重因素,但其因果关系尚未完全清楚。

In the last 10 years,homocysteine(Hcy)has been regarded as a marker of cardiovascular disease and a definite risk factor for many other diseases.Hcy is biosynthesized from methionine through multiple steps and then goes through one of two major metabolic pathways:remethylation and transsulfuration.Hyperhomocysteinemia(HHcy)is a state in which too much Hcy is present in the body.The main cause of HHcy is a dysfunction of enzymes and cofactors associated with the process of Hcy biosynthesis.Other causes include excessive methionine intake,certain diseases and side effects of some drugs.HHcy is a trigger for many diseases,such as atherosclerosis,congestive heart failure,age-related macular degeneration,Alzheimer’s disease and hearing loss.There are many studies showing a positive relationship between Hcy level and various symptoms.We speculate that a high level of Hcy can be the sole reason or an aggravating factor in numerous diseases for which causal links are not fully understood.