Homocysteine: Its Possible Emerging Role in At-Risk Population Groups

Abstract

Increased plasma homocysteine is a risk factor for several pathological disorders. The present review focused on the role of homocysteine (Hcy) in different population groups, especially in risk conditions (pregnancy, infancy, old age), and on its relevance as a marker or etiological factor of the diseases in these age groups, focusing on the nutritional treatment of elevated Hcy levels. In pregnancy, Hcy levels were investigated in relation to the increased risk of adverse pregnancy outcomes such as small size for gestational age at birth, preeclampsia, recurrent abortions, low birth weight, or intrauterine growth restriction. In pediatric populations, Hcy levels are important not only for cardiovascular disease, obesity, and renal disease, but the most interesting evidence concerns study of elevated levels of Hcy in autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD). Finally, a focus on the principal pathologies of the elderly (cardiovascular and neurodegenerative disease, osteoporosis and physical function) is presented. The metabolism of Hcy is influenced by B vitamins, and Hcy-lowering vitamin treatments have been proposed. However, clinical trials have not reached a consensus about the effectiveness of vitamin supplementation on the reduction of Hcy levels and improvement of pathological condition, especially in elderly patients with overt pathologies, suggesting that other dietary and non-dietary factors are involved in high Hcy levels. The importance of novel experimental designs focusing on intra-individual variability as a complement to the typical case–control experimental designs and the study of interactions between different factors it should be emphasized.

Vitamin B6 and Diabetes: Relationship and Molecular Mechanisms

“…It was proposed that reduced levels of vitamin B6 might increase levels of homocysteine, as PLP is a cofactor for cystathionine-synthase (CBS) and cystathionine-lyase (CGL), which are involved in the metabolism of this compound [90]. Elevated homocysteine levels are associated with obesity; in addition, they can impair endothelial function and lead to lipid accumulation in liver [91][92][93].…”

Changes in Serum Homocysteine Concentrations and their Prognostic Value in Pregnant Chinese Women with Preeclampsia : A Retrospective Study

“…The vascular endothelium can be harmed by elevated concentrations of homocysteine [5], which is a nonprotein amino acid that is formed after cleavage of the terminal methyl group from methionine [6,7]. Furthermore, high level of homocysteine in early pregnancy was a risk factor for pregnancy loss, abruptio placenta, stillbirth, and miscarriage [8], and homocysteine concentrations may be useful when screening for preeclampsia [9], although its prognostic value remains unclear.…”

Comparison of a new enzymatic assay for serum homocysteine on Toshiba TBA-c16000 against an immunoassay on Abbott Architect

“…While it is uncertain whether Hcy is an indicator or a cause of disease, recent studies revealed other relationships between the elevated Hcy levels and pathological disorders, including neurodegenerative disease, renal dysfunction, cognitive impairments, and defective congenital development [8]. Accordingly, multiple assays using chromatography, enzymatic assays, and immunoassays have been developed for accurate evaluation of Hcy levels and are practiced on automated platforms [9].…”