Abstract
BACKGROUND: Psoriasis and depression frequently coexist, creating a complex, bidirectional relationship that complicates treatment. This study, integrating clinical assessments with transcriptomic and metabolomic analyses, hypothesizes that TYK2 (tyrosine kinase 2) inhibitors possess a dual therapeutic potential to simultaneously address both dermatological manifestations of psoriasis and the frequently accompanied depressive symptoms.
METHODS: In a cohort of 298 psoriasis patients evaluated using the Hospital Anxiety and Depression Scale (HADS), participants were categorized into a TYK2 inhibitor group, a Janus kinase (JAK) inhibitor group, and a non-JAK pool (comprising interleukin [IL]-23 biologics, IL-17 biologics, and other treatments) to avoid overlapping JAK pathway inhibition. Statistical analysis was conducted using generalized linear models (GENMOD), with adjustments for the following covariates: age, sex, Psoriasis Area and Severity Index (PASI), body surface area (BSA), prior systemic or biologic therapy within 12 months, disease duration, and phototherapy history.
RESULTS: For HADS-D scores, the TYK2 inhibitor group showed significantly lower values compared with the non-JAK pool (β = 1.23, 95% confidence interval [CI]: 0.37-2.10). However, no significant differences were observed when compared with the IL-23 biologics group (β = 0.67, 95% CI: -0.76-2.10) or the JAK inhibitor group (β = 0.84, 95% CI: -1.54-3.21). Transcriptomic analysis of peripheral blood revealed significant downregulation of genes related to the IL-6 receptor, long-term depression pathways, and Th17 cell differentiation, while pathways associated with neuronal activity were upregulated. Metabolomic profiling highlighted a decrease in kynurenic acid, which is known for its pro-inflammatory and depressive effects, and an increase in 1H-indole-3-propanoic acid, an anti-inflammatory metabolite with neuroprotective properties. It is important to note that these findings are based on exploratory omics analyses, for which false discovery rate (FDR) control was applied.
CONCLUSIONS: These findings provide a hypothesis that TYK2 inhibitors disrupt the persistent "peripheral inflammation-central depression" cycle by targeting the IL-23/Th17 axis and modulating the IL-6/tryptophan metabolic hub. This innovative, multi-targeted approach represents a possibility for treating psoriasis with comorbid depression, offering not only clinical improvements in both skin and mood symptoms but also enhanced patient adherence to treatment regimens.