Immunoassay of S-adenosylmethionine and S-adenosylhomocysteine: the methylation index as a biomarker for disease and health status

Abstract

Background S-Adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) are relevant to a variety of diseases. Previous reports that quantified SAM and SAH were based on HPLC or LC–MS/MS. No antibody against SAM has been generated, and the antibody against SAH cannot be used with blood samples. Immunoassays have not been used to measure SAM and SAH. In this study, ELISA was used to measure blood SAM and SAH levels.ResultsSpecific antibodies against SAM were produced for the first time using a stable analog as the antigen. The monoclonal antibodies against SAM and SAH were characterized. No cross-reactivity was detected for the analyzed analogs. For the anti-SAM antibodies, the ELISA sensitivity was ~2 nM, and the affinity was 7.29 × 1010 L/mol. For the anti-SAH antibodies, the sensitivity was ~15 nM, and the affinity was 2.79 × 108 L/mol. Using high-quality antibodies against SAM and SAH, immunoassays for the detection of SAM and SAH levels in blood and tissue samples were developed. Clinical investigations using immunoassays to measure SAM, SAH and the methylation index (MI) in normal and diseased samples indicated that (1) the SAM level is age and gender dependent; (2) the SAM level is associated with the severity of liver diseases, inflammatory reactions and other diseases; and (3) the methylation index (MI) is significantly reduced in many diseases and may serve as a screening biomarker to identify potentially unfavorable health conditions.ConclusionIt is possible to generate antibodies against active small biomolecules with weak immunogenicity, such as SAM and SAH, using traditional hybridoma technology. The antigens and antibodies described here will contribute to the development of immunoassays to measure SAM, SAH and related molecules. These assays enable the MI to be measured specifically, accurately, easily and quickly without costly equipment. This preliminary study indicates that the MI could be an effective indicator of general health, except under conditions that may alter the value of the MI, such as special diets and medications.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-016-2296-8) contains supplementary material, which is available to authorized users.

One-Carbon Metabolism in Alzheimer’s Disease and Parkinson’s Disease Brain Tissue

“…Correlation analysis was performed on all pairs of metabolites with Hcy as the main compound of interest due to its adverse effects and, additionally, with all pairwise combinations between betaine, methionine, THF, and MTHF to capture a potential cross-talk between Hcy re-methylation pathways. We included the SAM/SAH calculated ratio for its pathophysiological utility [ 27 ], similarly to the case for THF/MTHF. Pearson’s correlation coefficients were computed for each diagnostic group and compared with the control group using Fisher’s z-transformation.…”

Exploring the Role of Nutraceuticals in Major Depressive Disorder (MDD): Rationale, State of the Art and Future Prospects

“…For example, lower levels of MAT2A and SAMe may negatively affect the regulation of some critical components of monoaminergic neurotransmitters either by direct mechanisms (modulating their catabolic enzymes, transporters and receptors) and indirect (influencing the synthesis of tetrahydrobiopterin (BH4) cofactor, a critical component involved in monoamine synthesis) [ 127 ]. Moreover, previous studies have found substantial alterations on the SAH/SAMe ratio in patients with MDD, together with an altered methylation index [ 129 ]. This abnormal methylation status could influence adversely certain critical targets like BDNF; therefore, playing a relevant role in the onset and progression of MDD [ 130 ].…”

S-Adenosyl Methionine and Transmethylation Pathways in Neuropsychiatric Diseases Throughout Life

“…It has been difficult for clinicians to employ an easy measure the levels of SAMe and SAH in blood or tissue samples. However, research has recently generated antigens and antibodies that will pave the way for immunoassays for SAMe and related molecules [187]. This development of Immunoassays of SAMe and SAH should in the future provide a methylation index as a biomarker for disease and health status and tissue specific and brain region prevalence abundance of SAMe levels.…”