Lysophosphatidic acid levels in cerebrospinal fluid and plasma samples in patients with major depressive disorder

Major depressive disorder (MDD) is the most common psychiatric disorders. However, a biochemical marker has yet to be established for clinical purposes. It is proposed that lysophosphatidic acid (LPA, 1-acyl-2-sn-glycerol-3-phosphoate) plays some important roles in emotional regulation of experimental animals. Therefore, in this study, we measured LPA levels using enzyme-linked immunosorbent assays of cerebrospinal fluid (CSF) and plasma samples from patients with MDD. The participants were 52 patients and 49 normal healthy controls for CSF study, and 47 patients and 44 controls for plasma study. We used the Japanese version of the GRID Hamilton Depression Rating Scale (17-item version) for the assessment of depressive symptoms. We found no associations between LPA levels (CSF or plasma) and either diagnosis or severity of MDD, or with psychotropic medication. In conclusion, our data suggest that LPA levels likely would not serve as a practical biomarker of MDD.