Vestibulodynia: Understanding Pathophysiology and Determining Appropriate Treatments

Vestibulodynia (VBD) is a chronic pelvic pain condition that affects 1 in 6 reproductive aged women, yet remains ineffectively treated by standard trial-and-error approaches. The investigators have identified two distinct VBD subtypes that may benefit from different types of treatment: 1) VBD peripheral (VBD-p) subtype characterized by localized pain specific to the vulvar vestibule, and 2) VBD central (VBD-c) subtype characterized by pain at both vaginal and remote body regions. Preliminary data further demonstrate that VBD-p and VBD-c subtypes differ with respect to patient reported outcomes (e.g., physical and mental health), production of cytokines (intracellular proteins that regulate the activity of pain nerves and inflammatory processes), and expression of microRNAs (small non-coding RNA molecules that regulate gene expression). Women with VBD-p exhibit normal psychological profiles; balanced circulating pro- and anti-inflammatory cytokines; and dysregulation in microRNAs that regulate the expression of genes in estrogen pathways. In contrast, women with VBD-c report decreased functional status and increased somatization; increased pro-inflammatory but not anti-inflammatory cytokines; and dysregulation in microRNAs that regulate the expression of genes relevant to muscle, nerve, and immune cell function. Based on these data, the investigators hypothesize that two VBD-p and VBD-c subtypes will preferentially respond to peripheral, central, or combined treatments and can be distinguished by cytokine and microRNA profiles. These hypotheses will be tested in a phase III clinical trial that evaluates diverse treatment strategies in women with VBD-p and VBD-c. Participants will be randomly assigned to one of four parallel arms: peripheral treatment with 5% lidocaine + 0.5 mg/ml 0.02% estradiol compound cream, 2) central treatment with the tricyclic antidepressant nortriptyline, 3) combined peripheral and central treatments, or 4) placebo. The treatment phase will last 4 months (with a 6-week titration at treatment initiation and 2-week taper period at 4 months), with outcome measures and biomarkers assessed at 4 time points (0, 2, 4, and 6 months). First, the investigators will compare the efficacy of treatments in alleviating pain among women with VBD-p and VBD-c using standardized tampon insertion with a numeric rating scale and self-reported pain on the McGill Pain Questionnaire. Next, the investigators will compare the efficacy of treatments in improving perceived physical, mental, and sexual health among women with VBD-p and VBD-c using standardized questionnaires. Finally, investigators will measure cytokines and microRNAs in women with VBD-p versus VBD-c using multiplex assays and RNA sequencing, and determine the ability of these biomarkers to predict treatment response. Successful completion of the proposed work will provide new insights into the mechanisms that drive pain perception and treatment response in two distinct VBD subtypes, and determine the efficacy of peripheral, central, and combined therapies in reversing this pain. Such findings will readily translate to improved patient care, permitting the millions of women with VBD, their partners, and clinicians to make more informed decisions about pain management.