What is Homocysteine (Genova)?

Homocysteine is a sulphur-containing amino acid and is an intermediate metabolite of methionine metabolism.

Homocysteine is a well-known cardiovascular disease risk factor.

– Metabolized by two pathways; trans-methylation and trans-sulphation pathways.
– Regulation of homocysteine depends on certain key nutrients, including vitamin B12, vitamin B6 and folic acid.
– High homocysteine levels are an important biomarker in risk assessment for CVD, strokes and other inflammatory diseases.
– Functional biomarker for low B6, B9 and B12; also excess methionine.
– It may also give indications of polymorphisms affecting methylation

Age, gender, folate, serum vitamin B12, serum creatinine and multivitamin usage are determinants of plasma homocysteine concentration. In population studies, total plasma homocysteine concentrations are higher in men than in women, increase markedly with age and are inversely correlated with blood folate, serum vitamin B12 and serum creatinine. Users of multivitamins have a lower homocysteine levels than nonusers.

High levels:

The most common dietary deficiency leading to homocysteine elevation and the associated increase in heart disease risk involves vitamin B12 and folic acid. You can have normal blood levels of these vitamins but still not have enough for your body’s enzymes to function properly. Dietary deficiency of vitamin B12 and folic acid are associated with increased risk of many diseases, including anemia and the associated chronic fatigue.

Vitamin B6 deficiency may also result in elevated concentrations of homocysteine in blood, which leads to increased risk of heart disease.

A high level of homocysteine in the blood (hyperhomocysteinemia) makes a person more prone to endothelial cell injury, which leads to inflammation in the blood vessels, which in turn may lead to atherogenesis, which can result in ischemic injury. Abnormally high levels of homocysteine in the serum, above 15 µmol/L, are a medical condition called hyperhomocysteinemia.

Hyperhomocysteinemia is a possible risk factor for coronary artery disease. Coronary artery disease occurs when an atherosclerotic plaque blocks blood flow to the coronary arteries, which supply the heart with oxygenated blood.

High levels of homocysteine can also be a risk factor for the development of a wide range of diseases, including thrombosis, neuropsychiatric illness, and fractures.

References:

1. https://www.merckmanuals.com/professional/hematology-and-oncology/thrombotic-disorders/hyperhomocysteinemia#v12779073
2. https://www.ncbi.nlm.nih.gov/pubmed/10063987
3. https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(03)00438-1/fulltext
4. https://www.karger.com/Article/Abstract/326301
5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2935890/
6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3321271/
7. https://www.nejm.org/doi/full/10.1056/NEJMoa032739
8. https://repub.eur.nl/pub/8452
9. https://www.ahajournals.org/doi/10.1161/01.ATV.21.1.74