This article was originally published here

Curr Med Chem. November 24, 2021. doi: 10.2174/0929867328666211125092438. Online before printing.

Background: D-amino acids are present in the human body and come from diet, bacterial flora and endogenous synthesis (at least for D-serine, and possibly D-aspartic acid). D-amino acids are involved in important physiological processes (for example, D-serine and D-aspartate act as co-agonists and agonists on N-methyl-D-aspartate receptors, respectively) and more and more The evidence associates D-amino acids with different pathological states.

Method: The determination of D-amino acid levels in blood is mainly based on the separation of enantiomers by high performance liquid chromatography. Since the number of D-enantiomers is small compared with the corresponding L-amino acids, and the background noise associated with the biological matrix is ​​high, positive and negative controls are absolutely necessary to obtain reliable values.

Results: It has been reported that changes in blood D-serine levels are in several neurological and psychiatric diseases: it has been proposed as a promising biomarker for schizophrenia, Alzheimer's disease and amyotrophic lateral sclerosis. In fact, D-serine level seems to be a suitable predictor of antidepressant response in major depression and post-traumatic stress disorder, as well as a prognostic biomarker of early cognitive decline, especially when both D-serine and D-serine are considered. When the proline level. In addition, D-amino acids appear to be useful biomarkers for pathologies unrelated to the central nervous system, such as pancreatic cancer and chronic kidney disease.

Conclusion: This is the first review to use D-amino acid blood concentration measurement as a diagnostic and prognostic biomarker. The experimental evidence that D-amino acids participate in various physiological pathways indicates that their levels in other pathologies, such as diabetes, can also be studied. In short, the level of D-amino acids in the blood may represent a new diagnostic peripheral biomarker for various diseases. Further research is needed to standardize/automate the determination and confirm its clinical effectiveness.