Targeted metabolomics to assess positive effects of empagliflozin in a Parkinson's disease model – focused on the kynurenine pathway and oxidative stress

Sodium-glucose cotransporter 2 (SGLT2) inhibitors, such as empagliflozin (EMPA), have been increasingly suggested to exert neuroprotective effects, but their overall metabolic impact in Parkinson’s disease (PD) remains unclear. In this study, we investigated the effect of EMPA in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model, focusing on tryptophan metabolism pathways, neurotransmitters and antioxidant system markers in striatum. For the quantification of metabolites, a targeted ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC–MS/MS) was performed. Multivariate statistical approaches, including partial least squares–discriminant analysis (PLS-DA) and cluster analyses were applied to characterize group-specific metabolic patterns and alterations. Differences between groups were identified using univariate analyses, and metabolites with False Discovery Rate (FDR)–adjusted p -values < 0.05 were considered statistically significant. Multivariate statistical analyses revealed substantially distinct metabolic patterns in EMPA-treated PD groups compared to control group. Notably, in our in vivo PD model EMPA administration significantly enhanced the production of neuroprotective metabolites of kynurenine pathway, including kynurenic acid (KA), anthranilic acid (AA), xanthurenic acid (XA) and the respective calculated enzyme activities, and oxidative stress index. EMPA treatment further reduced the oxidative stress and neurotoxicity through the modulation of glutathione (GSH) system and reduction of 3-hydroxykynurenine (3OHK) in Sirtuin3 knock-out (S3KO) animals. The results highlight that EMPA modulates tryptophan metabolism and reduces oxidative stress in MPTP-induced PD in striatum. These findings further confirm the relevance of KA as a promising therapeutic approach and supporting the potential role of EMPA in neuroprotection.