Sexual dysfunction in multiple sclerosis: the role of orexin-A and calpain-2 - a pilot study

BACKGROUND: Sexual dysfunction (SD) is a common autonomic symptom in patients with multiple sclerosis (pwMS), significantly affecting their quality of life. Alterations in serum levels of calpain-2 (CAPN2) and orexin-A (ORX-A) may contribute to SD development. OBJECTIVE: This study aimed to assess the prevalence of SD in pwMS and investigate its association with serum CAPN2 and ORX-A levels. METHODS: Fifty-seven pwMS diagnosed with relapsing-remitting MS were enrolled. Participants completed the Arizona Sexual Experiences Scale (ASEX), Multiple Sclerosis Quality of Life-54 (MSQoL-54), Beck Depression Inventory (BDI), and Composite Autonomic Symptom Score-31 (COMPASS-31). Serum CAPN2 and ORX-A levels were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: SD prevalence was 50.9%. Age, gender, depression status, and serum ORX-A levels were significant predictors of SD. Serum ORX-A levels were significantly lower in pwMS with SD, while CAPN2 levels did not differ. Depression scores correlated moderately with autonomic dysfunction scores. Spinal cord lesions were not significantly associated with SD. CONCLUSION: Multiple factors contribute to sexual dysfunction in pwMS. While serum calpain-2 levels did not show a significant association with SD in this study, reduced serum orexin-A levels appear to play a key role in its pathogenesis. Further research is needed to clarify the role of calpain-2 and other molecular mechanisms. Identification of biological markers such as orexin-A may improve management strategies for SD in MS.