Metabotropic glutamate receptor 5 expression associates with pain and inflammatory pathways in interstitial cystitis

Interstitial cystitis (IC)/bladder pain syndrome (BPS) is a chronic condition with severe pelvic pain and urinary symptoms significantly impairing quality of life. This study investigated the clinical relevance of the metabotropic glutamate receptor (mGluR) family in IC/BPS. Bladder biopsy samples were taken from 61 patients, including 42 Hunner-type IC, 11 non-Hunner type IC, and 8 controls without IC. Gene expression analysis revealed that mGluR2, mGluR3, and mGluR5 were significantly elevated in patients with IC/BPS compared to controls. Among these, mGluR5 showed the strongest association with pain severity, fibrosis, and lymphoplasmacytic infiltration. Patients with Hunner-type IC also exhibited increased expression of p65 and interleukin-1β, suggesting activation of inflammatory response modulation in IC/BPS. These findings suggest that mGluR5 may contribute to pain through immune response modulation in IC/BPS. Targeting mGluR5 could represent a promising therapeutic strategy to alleviate symptoms and improve patient quality of life.