Women's Experience of Living with Vulvodynia Pain: Why They Participated in a Randomized Controlled Trial of Acupuncture.

Introduction: Vulvodynia is vulvar pain lasting at least 3-months without clear identifiable cause that may have other associated factors. The aim, to explore motivations of women participating in a double-blind randomized controlled trial of acupuncture for vulvodynia. Methods: Responses to the question: "Tell me about why you decided to participate in this study" were analyzed using conceptual content analysis to identify patterns in motivation for study participation. Results: Four patterns emerged: 1) desire to address uncontrolled pain, 2) desire for understanding, 3) wish to contribute to knowledge generation, and 4) need to remove cost barriers. Conclusion: Motivations indicate vulvodynia-specific aspects of acceptability of acupuncture. Clinical Trial Registration: NCT03364127.

Specialized Pro-resolving Mediators Reduce Pro-nociceptive Inflammatory Mediator Production in Models of Localized Provoked Vulvodynia.

Localized provoked vulvodynia (LPV) is the most common cause of chronic dyspareunia in premenopausal women, characterized by pain with light touch to the vulvar vestibule surrounding the vaginal opening. The devastating impact of LPV includes sexual dysfunction, infertility, depression, and even suicide. Yet, its etiology is unclear. No effective medical therapy exists; surgical removal of the painful vestibule is the last resort. In LPV, the vestibule expresses a unique inflammatory profile with elevated levels of pro-nociceptive proinflammatory mediators prostaglandin E2 (PGE2) and interleukin-6 (IL-6), which are linked to lower mechanical sensitivity thresholds. Specialized pro-resolving mediators (SPMs), lipids produced endogenously within the body, hold promise as an LPV treatment by resolving inflammation without impairing host defense. Ten of 13 commercially available SPMs reduced IL-6 and PGE2 production by vulvar fibroblasts, administered either before or after inflammatory stimulation. Using a murine vulvar pain model, coupling proinflammatory mediator quantification with mechanical sensitivity threshold determination, topical treatment with the SPM, maresin 1, decreased sensitivity and suppressed PGE2 levels. Docosahexaenoic acid, a precursor of maresin 1, was also effective in reducing PGE2 in vulvar fibroblasts and rapidly restored mouse sensitivity thresholds. Overall, SPMs and their precursors may be a safe and efficacious for LPV. Perspective: Vulvodynia, like many pain conditions, is difficult to treat because disease origins are incompletely understood. Here, we applied our knowledge of more recently discovered vulvodynia disease mechanisms to screen novel therapeutics. We identified several specialized pro-resolving mediators as likely potent and safe for treating LPV with potential for broader application.

Effect of gabapentin on sexual function in vulvodynia: a randomized, placebo-controlled trial.

BACKGROUND: Sexual dysfunction is common in women with vulvodynia. OBJECTIVE: The purpose of this study was (1) to evaluate whether extended-release gabapentin is more effective than placebo in improving sexual function in women with provoked vulvodynia and whether there is a relationship between treatment outcome and pelvic pain muscle severity that is evaluated by palpation with standardized applied pressure and (2) to evaluate whether sexual function in women with provoked vulvodynia would approach that of control subjects who report no vulvar pain either before or after treatment. STUDY DESIGN: As a secondary outcome in a multicenter double-blind, randomized crossover trial, sexual function that was measured by the Female Sexual Function Index was evaluated with gabapentin (1200-3000 mg/d) compared with placebo. Pain-free control subjects, matched by age and race, also completed Female Sexual Function Index for comparison. RESULTS: From August 2012 to January 2016, 230 women were screened at 3 academic institutions, and 89 women were assigned randomly to treatment. Gabapentin was more effective than placebo in improving overall sexual function (adjusted mean difference, 1.3; 95% confidence interval, 0.4-2.2; P=.008), which included desire (mean difference, 0.2; 95% confidence interval, 0.0-3.3; P=.04), arousal (mean difference, 0.3; 95% confidence interval, 0.1-0.5; P=.004), and satisfaction (mean difference, 0.3; 95% confidence interval, 0.04-0.5; P=.02); however, sexual function remained significantly lower than in 56 matched vulvodynia pain-free control subjects. There was a moderate treatment effect among participants with baseline pelvic muscle pain severity scores above the median on the full Female Sexual Function Index scale (mean difference, 1.6; 95% confidence interval, 0.3-2.8; P=.02) and arousal (mean difference, 0.3; 95% confidence interval, 0.1-0.6; P=.01) and pain domains (mean difference, 0.4; 95% confidence interval, 0.02-0.9; P=.04). CONCLUSION: Gabapentin improved sexual function in this group of women with provoked vulvodynia, although overall sexual function remained lower than women without the disorder. The most statistically significant increase was in the arousal domain of the Female Sexual Function Index that suggested a central mechanism of response. Women with median algometer pain scores >5 improved sexual function overall, but the improvement was more frequent than the pain domain. We hypothesize that gabapentin may be effective as a pharmacologic treatment for those women with provoked vulvodynia and increased pelvic muscle pain on examination.

Gabapentin for the Treatment of Vulvodynia: A Randomized Controlled Trial.

OBJECTIVE: To evaluate whether extended-release gabapentin is more effective than placebo among women with vulvodynia. METHODS: In a multicenter double-blind, placebo-controlled randomized crossover trial, gabapentin (1,200-3,000 mg/d) was compared with a placebo. The primary outcome was mean pain intensity (0, no pain at all to 10, worst pain ever) on the tampon test (a standardized tampon insertion and removal test used as a surrogate marker for dyspareunia) during the last 7 days of the maintenance phase. Secondary outcomes included sexual intercourse pain and daily pain. A sample size of 53 provided 90% power to detect a 1-point reduction on the tampon test (.05 level, two-sided) between the two treatment phases. RESULTS: From August 2012 to January 2016, 230 women were screened at three academic institutions and 89 (mean age 37 years; 65% black) were randomized: 45 to gabapentin first and then placebo and 44 to placebo first and then gabapentin. Tampon test pain with gabapentin was not different compared with the placebo (adjusted mean 4.0, 95% CI 3.0-4.9 vs 4.3, 95% CI 3.4-5.2, difference -0.3, 95% CI -0.7 to 0.0; P=.07). Gabapentin also did not improve pain over placebo for sexual intercourse pain (adjusted mean 3.9, 95% CI 2.4-5.3 vs 4.0, 95% CI 2.5-5.4, difference -0.1, 95% CI -0.9 to 0.6; P=.76) and daily pain (adjusted mean 2.7, 95% CI 1.8-3.6 vs 2.9, 95% CI 2.0-3.8, difference -0.2, 95% CI -0.5 to -0.2; P=.36). Subset analyses found that longer pain duration and oral contraceptive nonuse were associated with minimal improvement in tampon test pain with gabapentin. CONCLUSION: In this cohort, extended-release gabapentin, as compared with a placebo, did not reduce tampon test pain. These data do not support the recommendation of gabapentin alone as treatment for vulvodynia. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT01301001.

Toll-Like Receptor Signaling Contributes to Proinflammatory Mediator Production in Localized Provoked Vulvodynia.

OBJECTIVES: Localized provoked vulvodynia (LPV) afflicts approximately 8% of women in the United States and represents a huge financial, physical, and psychological burden. Women with LPV experience intense pain localized to the vulvar vestibule (area immediately surrounding vaginal opening). We have identified mechanisms involved in the development of LPV whereby vulvar fibroblasts respond to proinflammatory stimuli to perpetuate an inflammatory response that causes pain. However, these mechanisms are not fully elucidated. Therefore, we explored the role of toll-like receptors (TLRs), a class of innate immune receptors that rapidly respond to microbial assaults. MATERIALS AND METHODS: To determine whether TLRs are expressed by vulvar fibroblasts and whether these contribute to proinflammatory mediator production and pain in LPV, we examined TLR expression and innate immune responses in fibroblasts derived from painful vestibular regions compared with nonpainful external vulvar regions. RESULTS: Human vulvar fibroblasts express functional TLRs that trigger production of inflammatory mediators associated with chronic pain. We focused on the TLR-7-imiquimod proinflammatory interaction, because imiquimod, a ligand of TLR-7, may exacerbate pain in women during treatment of human papillomavirus-associated disease. CONCLUSIONS: Human vulvar fibroblasts express a broad spectrum of TLRs (a new finding). A significantly higher TLR-mediated proinflammatory response was observed in LPV case vestibular fibroblasts, and with respect to the imiquimod-TLR 7 interaction, development of chronic vestibular pain and inflammation may be a possible sequelae of treatment of vulvar human papillomavirus-associated disease. Suppressing enhanced TLR-associated innate immune responses to a spectrum of pathogen-associated molecular patterns may represent a new/effective therapeutic approach for vulvodynia.

Recruitment methods in a clinical trial of provoked vulvodynia: Predictors of enrollment.

BACKGROUND: Successful recruitment in clinical trials for chronic pain conditions is challenging, especially in women with provoked vulvodynia due to reluctance in discussing pain associated with sexual intercourse. The most successful recruitment methods and the characteristics of women reached with these methods are unknown. OBJECTIVE: To compare the effectiveness and efficiency of four recruitment methods and to determine socioeconomic predictors for successful enrollment in a National Institutes of Health-sponsored multicenter clinical trial evaluating a gabapentin intervention in women with provoked vulvodynia. METHODS: Recruitment methods utilized mass mailing, media, clinician referrals and community outreach. Effectiveness (number of participants enrolled) and efficiency (proportion screened who enrolled) were determined. Socioeconomic variables including race, educational level, annual household income, relationship status, age, menopausal status and employment status were also evaluated regarding which recruitment strategies were best at targeting specific cohorts. RESULTS: Of 868 potential study participants, 219 were enrolled. The most effective recruitment method in enrolling participants was mass mailing ( p < 0.001). There were no statistically significant differences in efficiency between recruitment methods ( p = 0.11). Relative to clinician referral, black women were 13 times as likely to be enrolled through mass mailing (adjusted odds ratio 12.5, 95% confidence interval, 3.6-43.1) as white women. There were no differences in enrollment according to educational level, annual income, relationship status, age, menopausal status, or employment status and recruitment method. CONCLUSION: In this clinical trial, mass mailing was the most effective recruitment method. Race of participants enrolled in a provoked vulvodynia trial was related to the recruitment method.

A Role for Bradykinin Signaling in Chronic Vulvar Pain.

Chronic vulvar pain is alarmingly common in women of reproductive age and is often accompanied by psychological distress, sexual dysfunction, and a significant reduction in quality of life. Localized provoked vulvodynia (LPV) is associated with intense vulvar pain concentrated in the vulvar vestibule (area surrounding vaginal opening). To date, the origins of vulvodynia are poorly understood, and treatment for LPV manages pain symptoms, but does not resolve the root causes of disease. Until recently, no definitive disease mechanisms had been identified; our work indicates LPV has inflammatory origins, although additional studies are needed to understand LPV pain. Bradykinin signaling is one of the most potent inducers of inflammatory pain and is a candidate contributor to LPV. We report that bradykinin receptors are expressed at elevated levels in LPV patient versus healthy control vestibular fibroblasts, and patient vestibular fibroblasts produce elevated levels of proinflammatory mediators with bradykinin stimulation. Inhibiting expression of one or both bradykinin receptors significantly reduces proinflammatory mediator production. Finally, we determined that bradykinin activates nuclear factor (NF)κB signaling (a major inflammatory pathway), whereas inhibition of NFκB successfully ablates this response. These data suggest that therapeutic agents targeting bradykinin sensing and/or NFκB may represent new, more specific options for LPV therapy. PERSPECTIVE: There is an unmet need for the development of more effective vulvodynia therapies. As we explore the mechanisms by which human vulvar fibroblasts respond to proinflammatory/propain stimuli, we move closer to understanding the origins of chronic vulvar pain and identifying new therapeutic targets, knowledge that could significantly improve patient care.

Site-specific mesenchymal control of inflammatory pain to yeast challenge in vulvodynia-afflicted and pain-free women.

Fibroblast strains were derived from 2 regions of the lower genital tract of localized provoked vulvodynia (LPV) cases and pain-free controls. Sixteen strains were derived from 4 cases and 4 controls, age and race matched, after presampling mechanical pain threshold assessments. Strains were challenged with 6 separate stimuli: live yeast species (Candida albicans, Candida glabrata, Candida tropicalis, and Saccharomyces cerevisiae), yeast extract (zymosan), or inactive vehicle. Production of prostaglandin E2 (PGE2) and interleukin 6 (IL-6) were proinflammatory response measures. Highest IL-6 and PGE2 occurred with vestibular strains after C albicans, C glabrata, and zymosan challenges, resulting in the ability to significantly predict IL-6 and PGE2 production by genital tract location. After C albicans and C glabrata challenge of all 16 fibroblast strains, adjusting for dual sampling of subjects, PGE2 and IL-6 production significantly predicted the presampling pain threshold from the genital tract site of sampling. At the same location of pain assessment and fibroblast sampling, in situ immunohistochemical (IHC)(+) fibroblasts for IL-6 and Cox-2 were quantified microscopically. The correlation between IL-6 production and IL-6 IHC(+) was statistically significant; however, biological significance is unknown because of the small number of IHC(+) IL-6 fibroblasts identified. A low fibroblast IL-6 IHC(+) count may result from most IL-6 produced by fibroblasts existing in a secreted extracellular state. Enhanced, site-specific, innate immune responsiveness to yeast pathogens by fibroblasts may be an early step in LPV pathogenesis. Fibroblast strain testing may offer an attractive and objective marker of LPV pathology in women with vulvodynia of inflammatory origin.

Identification of novel mechanisms involved in generating localized vulvodynia pain.

OBJECTIVE: Our goal was to gain a better understanding of the inflammatory pathways affected during localized vulvodynia, a poorly understood, common, and debilitating condition characterized by chronic pain of the vulvar vestibule. STUDY DESIGN: In a control matched study, primary human fibroblast strains were generated from biopsies collected from localized provoked vulvodynia (LPV) cases and from age- and race-matched controls. We then examined intracellular mechanisms by which these fibroblasts recognize pathogenic Candida albicans; >70% of vulvodynia patients report the occurrence of prior chronic Candida infections, which is accompanied by localized inflammation and elevated production of proinflammatory/pain-associated interleukin (IL)-6 and prostaglandin E2 (PGE2). We focused on examining the signaling pathways involved in recognition of yeast components that are present and abundant during chronic infection. RESULTS: Dectin-1, a surface receptor that binds C albicans cell wall glucan, was significantly elevated in vestibular vs external vulvar cells (from areas without pain) in both cases and controls, while its abundance was highest in LPV cases. Blocking Dectin-1 signaling significantly reduced pain-associated IL-6 and PGE2 production during the response to C albicans. Furthermore, LPV patient vestibular cells produced inflammatory mediators in response to low numbers of C albicans cells, while external vulvar fibroblasts were nonresponsive. Inhibition of nuclear factor kappa-light-chain-enhancer of activated B cells (proinflammatory transcription factor) nearly abrogated IL-6 and PGE2 production induced by C albicans, in keeping with observations that Dectin-1 signals through the nuclear factor kappa-light-chain-enhancer of activated B cells pathway. CONCLUSION: These findings implicate that a fibroblast-mediated proinflammatory response to C albicans contributes to the induction of pain in LPV cases. Targeting this response may be an ideal strategy for the development of new vulvodynia therapies.

Potency and Stability of Intradermal Capsaicin: Implications for Use as a Human Model of Pain in Multicenter Clinical Trials.

Intradermally injected capsaicin has been used extensively both as a human pain model and to assess analgesic efficacy. Factors such as dose, formulation, route, and site are known to affect its sensitivity. We determined whether potency and stability of capsaicin solutions were further sources of variability when following strict manufacturing guidelines. Capsaicin solution (1.0 mg/mL) was prepared according to Current Good Manufacturing Practice (cGMP) guidelines and aseptically filled into sterile amber borosilicate vials and stored at 5°C, 25°C, and 30°C. All samples were analyzed at one, three, six, and twelve months. Chemical stability was determined using HPLC and physical stability was evaluated by visual inspection of color changes, clarity, particulate matter, and product/ container closure abnormalities during each sampling time. Capsaicin intradermal injection was found to be sterile and retained 95% of the initial concentration for at least one year, regardless of studied storage temperatures (P<0.0001). Visual inspection indicated no changes in color, clarity, particulate matter, and product/ container closure abnormalities in all samples. These data show that capsaicin solutions (1.0 mg/mL) maintain their potency and stability over one year when manufactured according to cGMP guidelines. These results suggest that in clinical trials manufacturing of capsaicin solutions is recommended over extemporaneous compounding.

Rationale and design of a multicenter randomized clinical trial of extended release gabapentin in provoked vestibulodynia and biological correlates of response.

INTRODUCTION: Few randomized controlled trials (RCTs) have been conducted to establish evidence-based management protocols for provoked vestibulodynia (PVD), a chronic vulvar pain condition affecting approximately 14 million women in the U.S. We describe the rationale and design of an NIH funded multicenter clinical trial utilizing an extended release formulation of gabapentin (G-ER), an intervention that preliminary data suggest may be efficacious for this condition. OBJECTIVES: 1) to determine if pain from tampon insertion (primary outcome measure) is lower in PVD patients when treated with G-ER compared to when treated with placebo and 2) to determine if G-ER reduces vulvar mechanical hyperalgesia, vaginal muscle pain to palpation, the number and intensity of somatic tenderpoints, spontaneous and provoked pain to intradermal capsaicin with an accompanying increase in cardiac beat-to-beat variability and to identify mechanistically-based PVD subtypes. Additional outcomes include subject reported intercourse pain and summative 24-hour pain. METHODS: This 16-week, randomized, double-blind, placebo-controlled, crossover study will enroll 120 women 18 years and older who report tenderness localized to the vulvar vestibule, pain with tampon insertion, and, when sexually active, insertional dyspareunia. Electronically entered daily diaries will be used to determine if pain is lower in PVD subjects when treated with G-ER (up to 3000 mg/d) compared to when treated with placebo. Psychophysiological measures will be obtained at baseline and after 2 weeks at the maximum tolerated dose. CONCLUSION: We will conduct the first multicenter RCT to confirm efficacy of an agent that is currently used in clinical practice for treating PVD.

Polymorphism in the SCN9A voltage-gated sodium channel gene associated with interstitial cystitis/bladder pain syndrome.

OBJECTIVE: To determine whether an association exists between interstitial cystitis/bladder pain syndrome (IC/BPS) and a nonsynonymous single nucleotide polymorphism in the SCN9A voltage-gated sodium channel gene previously associated with other chronic pain syndromes. MATERIALS AND METHODS: Germline deoxyribonucleic acid was sampled from archived bladder biopsy specimens from patients with a documented diagnosis of IC/BPS. Deoxyribonucleic acid from hysterectomy specimens was obtained as a control population. The genotype of single nucleotide polymorphism rs6746030 was determined by deoxyribonucleic acid sequencing after polymerase chain reaction amplification. Contingency analysis of genotypes was performed using Pearson's chi-square test and Fisher's exact test. RESULTS: Polymerase chain reaction product was obtained from 26 of 31 control specimens and from 53 of 57 IC/BPS biopsy specimens. Of the 26 control subjects, 3 (11.5%) were genotype AG and 23 were GG. In contrast, AA or AG genotypes were present in 21 of 53 (39.6%) patients with IC/BPS, a statistically significant difference compared with the controls (Pearson's chi-square, P=.036). Similarly, the A allele was at a greater frequency in the IC/BPS group using Fisher's exact test (P=.009). CONCLUSION: These data strongly suggest that pain perception in at least a subset of patients with IC/BPS is influenced by this polymorphism in the SCN9A voltage-gated sodium channel.

Oral desipramine and topical lidocaine for vulvodynia: a randomized controlled trial.

OBJECTIVE: To estimate the efficacy of common treatments for vulvodynia: topical lidocaine monotherapy, oral desipramine monotherapy, and lidocaine-desipramine combined therapy. METHODS: A 12-week randomized, double-blinded, placebo-controlled trial was conducted on 133 vulvodynia-afflicted women assigned to four treatment arms: placebo tablets-placebo cream, desipramine tablets-placebo cream, placebo tablets-lidocaine cream, and desipramine tablets-lidocaine cream. The tampon test was selected as primary end point using a modified intention-to-treat analysis. Twelve secondary end points were also examined. At completion of the 12-week randomized phase, women were examined "open label" through 52 weeks postrandomization. RESULTS: All treatment arms reported substantial tampon-test pain reduction: 33% reduction placebo cream-placebo tablet, 20% reduction lidocaine cream-placebo tablet, 24% reduction placebo cream-desipramine tablet, and 36% reduction lidocaine cream-desipramine tablet. Compared with placebo, we found no significant difference in tampon-test pain reduction with desipramine (t=0.90; P=.37) or lidocaine (t=1.27; P=.21). Of the remaining 12 outcome measures, only the Index of Sexual Satisfaction, improved with desipramine compared with placebo (t=-2.81; P=.006). During the open-label phase, women undergoing vestibulectomy surgery reported significantly improved pain as measured by cotton swab test and the McGill Pain Scale compared with nonsurgical alternatives. CONCLUSION: Oral desipramine and topical lidocaine, as monotherapy or in combination, failed to reduce vulvodynia pain more than placebo. Placebo or placebo-independent effects are behind the substantial pain improvement seen in all treatment allocations. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00276068. LEVEL OF EVIDENCE: I.

The tampon test for vulvodynia treatment outcomes research: reliability, construct validity, and responsiveness.

OBJECTIVE: A standardized tampon insertion and removal test, the Tampon Test provides an alternative to sexual intercourse pain as an outcome measure for vulvodynia research. We report upon the reliability, validity, and responsiveness to change of the Tampon Test as an outcome measure for vulvodynia clinical trials. METHODS: Outcome measures were assessed in women enrolled in the Vulvar Vestibulitis Clinical Trial, a randomized clinical trial of oral desipramine and topical lidocaine effectiveness. Reliability estimates of the Tampon Test using the Kappa statistic evaluated week-to-week measures at baseline. Tampon Test construct and discriminant validity were assessed through correlation with other outcome measures. Patients' ability to regularly perform the Tampon Test was compared with regularity of reporting intercourse pain. RESULTS: During the 2-week baseline phase, women with vulvodynia reported stable mean Tampon Test scores 4.6+/-2.6 (week -2); 4.6+/-2.7 (week -1); and 4.7+/-2.8 (week 0) with moderate week-to-week reliability (weighted Kappa 0.52). Over an 8-week phase of trial intervention, change in the Tampon Test measure significantly correlated to a number of outcome measures, including daily pain (r=0.42), intercourse pain (r=0.35), cotton swab vestibular pain (r=0.38), and the Brief Pain Inventory (r=0.49). Women with vulvodynia study participants performed the Tampon Test 96.3% of the requested time, which was twofold higher adherence than intercourse pain measurement (49.7%). CONCLUSION: The Tampon Test reflects a real life experience that is reliable, with good construct validity as shown by the breadth of correlated outcome measures. The Tampon Test is an appropriate outcome measure for vulvodynia research that can be considered for use as the primary efficacy endpoint in clinical trials of treatments for vulvodynia. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00276068 LEVEL OF EVIDENCE: II.