It is widely recognised that high homocysteine levels in the blood (hyperhomocysteinemia) can cause inflammation in the blood vessels, which in turn may lead to atherogenesis and ischemic injury.  High homocysteine levels are therefore a possible risk factor for coronary artery disease (CAD), or heart disease.

However a new study published in the Journal of Thrombosis and Haemostasis in April 2016 (conducted by Young Cheul Chung and colleagues, from Rockefeller University in New York City) has looked into the growing evidence to suggest that hyperhomocysteinemia is also correlated with Alzheimer’s disease and vascular dementia.  This study was undertaken to clarify the specific role of elevated homocysteine levels in Alzheimer’s disease pathophysiology.

The study was carried out on mice, and showed a promising link between high levels of homocysteine and Alzheimer’s disease.  It showed that diet-induced hyperhomocysteinemia in an Alzheimer’s disease mouse model leads to severe cerebral amyloid angiopathy and parenchymal amyloid-β deposition, as well as significant impairments in learning and memory, suggesting that elevated levels of plasma homocysteine and its metabolite, homocysteine thiolactone, contribute to Alzheimer’s disease pathology.

Commenting on an earlier study, Dr Susanne Sorensen, Head of Research at Alzheimer’s Society UK said that the molecule [homocysteine] is carried by everyone, but those who go on to develop some dementias appear to have higher levels of the compound.  She also stressed that research is needed to establish just what role if any homocysteine plays in the development of dementia and how best to keep levels of the molecule low.

Alzheimer’s disease is a progressive mental decline that can occur in middle to old age, due to a degeneration of the brain. It is the most common cause of premature senility, and is also the most common form of dementia, affecting 62% of those diagnosed.  Vascular dementia is another form, affecting 17% of those diagnosed.

Paul McGivern, Clinical Chemistry R&D Manager at global healthcare company Randox Laboratories, has commented

“Dementia is a terminal condition and with 850,000 people living with dementia in the UK, there is an urgent need for further research into the link between Alzheimer’s disease and homocysteine levels.  If we can better establish this link, it may give future researchers the tools necessary to find a prevention, or even a cure to this condition.”

With the number of dementia sufferers set to rise to over 1 million by 2025, soaring to 2 million by 2051, the need for further research into the link between homocysteine levels and Alzheimer’s disease has never been more pressing.

For health professionals

Randox Laboratories offer an automated test for the biochemistry measurement of homocysteine.  This is available for use on a wide range of manufacturer’s analysers.  Please contact reagents@randox.com for further information, or to request a kit insert or application.