A Cautionary Tale: Non-steroidal anti-inflammatory drug use and localized provoked vulvodynia

Localized provoked vulvodynia (LPV) is characterized by chronic vulvar pain upon light touch to the vulvar vestibule, a specialized ring of tissue immediately surrounding the vaginal opening. LPV affects ~14 million people in the US. Current treatments for LPV include nonsteroidal anti-inflammatory drugs (NSAIDs), but clinical evidence has demonstrated that they are ineffective for vulvar pain. Here, the effects of NSAID treatment on inflammation and resolution in an in vitro model of LPV were explored using enzyme-linked immunosorbent assays (ELISAs), calcium imaging, and metabololipidomics. Additionally, the effectiveness of NSAID treatment on mitigating chronic vulvar pain was assessed using a validated LPV mouse model that mimics key features of vulvodynia. These findings indicate that although NSAID treatment reduced pro-inflammatory eicosanoid production in vulvar fibroblasts, lipidomic analysis revealed that COX inhibition also downregulated levels of pro-resolving lipids, namely epoxyeicosatrienoic acids (EETs), lipoxins (LXs), and resolvin E-series (RvEs). In vivo, NSAID treatment did not restore vulvar pain thresholds back to baseline levels in mice. Overall, this study offers one possible explanation for previous reports of the ineffectiveness of NSAIDs on managing LPV-associated vulvar pain. PERSPECTIVE: Taking NSAIDs to manage chronic vulvar pain may downregulate levels of specialized pro-resolving lipid mediators, thereby resulting in prolonged pain and delayed inflammation resolution. This study provides one possible explanation for clinical reports of the ineffectiveness of NSAIDs in the mitigation of vulvodynia-associated pain.