Dysfunction in endocannabinoids, palmitoylethanolamide, and degradation of tryptophan into kynurenine in individuals with depressive symptoms

Table 1 Correlation of serum lipid biomarkers and tryptophan metabolites with the severity of depression (MADRS, CGI, and BDI-II total scores)

Biomarker	Total MADRS	Total CGI-severity of illness	Total BDI-II
2-AG (pmol/mL)	0.261*	0.124	0.219
2-OG (pmol/mL)	− 0.087	− 0.120	− 0.085
AEA (pmol/mL)	0.263*	0.178	0.211
OEA (pmol/mL)	0.059	0.490	0.014
PEA (pmol/mL)	0.287*	0.230*	0.162
Trp (µg/mL)	− 0.296**	− 0.305**	− 0.260*
Kyn (ng/mL)	0.204	0.277*	0.144
Kyn/Trp*1000	0.299**	0.376**	0.230*
5-HT (ng/mL)	− 0.299**	− 0.251*	− 0.159

Pearson’s partial correlation scores are corrected for sex, age, and BMI. Boldface indicates a significant difference at *alpha level = 0.05 and **alpha level = 0.01 after the false discovery rate (FDR) control procedure
2-AG 2-Arachidonoylglycerol, 2-OG 2-oleoylglycerol, AEA anandamide, OEA oleoylethanolamide, PEA palmitoylethanolamide, Kyn kynurenine, Trp tryptophan, 5-HT serotonin, MADRS Montgomery Asberg Depression Rating Scale, CGI Clinical Global Impression, BDI-II Beck Depression Inventory version-II

ISSN: 1741-7015