Assessing the Role of Inflammation in Chronic Pelvic Pain

INTRODUCTION: Chronic pelvic pain and endometriosis can be both characterized by different pathophysiology but similar initial clinical presentation. The role of the immune system and inflammation has been recently proposed as another potential etiology for endometriosis. The role of inflammation has also been proposed. The role of neuroinflammation and immune inflammation are two mechanisms that do not have current biomarker evaluation for diagnosis in chronic pelvic pain and endometriosis. Subjective testing for patients with chronic pelvic pain may hasten their path to diagnosis and treatment. The role of an objective biomarker for chronic pain and endometriosis may be the missing step in offering a definitive diagnosis. Proteomics offers research testing pathways and markers that can be assessed with large panel assays and can evaluate the role of inflammation in chronic pelvic pain and suspected endometriosis. These assays have been used for identifying the relationship of other chronic conditions, such as atherosclerosis. OBJECTIVE: The objective of this study was to identify an objective biomarker panel or pathway for chronic pelvic pain. Proteomics was used to assess for inflammation from a known assay panel. METHODS: Patients with chronic pelvic pain who had suspected endometriosis were approached for this study. They were tested with an inflammation biomarker panel as part of their preoperative evaluation. Laparoscopy was used to identify endometriosis, or determine it was not present. Patients with chronic pelvic pain were included if they met criteria of having pelvic pain that lasted 6 months or greater, and had an initial intake with standardized instrument (IPPS chronic pelvic pain tool). A biomarker proteomics panel of 90 proteins was tested for each participant. RESULTS: A total of 105 patients were included in the analysis, with 48 in the endometriosis group and 30 in the chronic pelvic pain group, and 30 in control group. Biomarker levels were compared between the two groups using t-tests, with a false discovery rate of 5% controlled using the Benjamini–Hochberg (BH) adjustment method. Biomarkers were shown to have substantial differentiation between the two groups, with standardized mean differences greater than 0.5 (i.e., difference in mean levels exceeding 0.5 standard deviations). However, after adjusting for the false discovery rate, none of the biomarkers reached statistical significance. CONCLUSIONS: While biomarkers for chronic pelvic pain were not identified through immune pathways of inflammation, this supports existing theories on neuroinflammation, which would require other assays for objective testing methods. Identifying objective testing methods may be a patient-centered means to reduce diagnostic bias and expedite diagnostic and treatment pathways. Additional research is needed and promising in finding objective measures for diagnosis of chronic pelvic pain for accessible means and improved patient outcomes.