Characteristics of the vaginal microbiome in women with and without clinically confirmed vulvodynia.

BACKGROUND: Vulvodynia (idiopathic vulvar pain) affects up to 8% of women by age 40 years, has a poorly understood etiology, and has variable treatment efficacy. Several risk factors are associated with vulvodynia from a history of yeast infections to depression and allergies. Recent work suggests an altered immune inflammatory mechanism plays a role in vulvodynia pathophysiology. Because the vaginal microbiome plays an important role in local immune-inflammatory responses, we evaluated the vaginal microbiome among women with vulvodynia compared with controls as 1 component of the immune system. OBJECTIVE: The objective of the study was to characterize the vaginal microbiome in women with clinically confirmed vulvodynia and age-matched controls and assess its overall association with vulvodynia and how it may serve to modify other factors that are associated with vulvodynia as well. STUDY DESIGN: We conducted a case-control study of 234 Minneapolis/Saint Paul-area women with clinically confirmed vulvodynia and 234 age-matched controls clinically confirmed with no history of vulvar pain. All participants provided vulvovaginal swab samples for culture-based and non-culture (sequencing)-based microbiological assessments, background and medical history questionnaires on demographic characteristics, sexual and reproductive history, and history of psychosocial factors. Vaginal microbiome diversity was assessed using the Shannon alpha diversity Index. Data were analyzed using logistic regression. RESULTS: Culture and molecular-based analyses of the vaginal microbiome showed few differences between cases and controls. However, among women with alpha diversity below the median (low), there was a strong association between increasing numbers of yeast infections and vulvodynia onset, relative to comparable time periods among controls (age-adjusted odds ratio, 8.1, 95% confidence interval, 2.9-22.7 in those with 5 or more yeast infections). Also among women with low-diversity microbiomes, we observed a strong association between moderate to severe childhood abuse, antecedent anxiety, depression, and high levels of rumination and vulvodynia with odds ratios from 1.83 to 2.81. These associations were not observed in women with high-diversity microbiomes. CONCLUSION: Although there were no overall differences in microbiome profiles between cases and controls, vaginal microbiome diversity influenced associations between environmental and psychosocial risk factors and vulvodynia. However, it is unclear whether vaginal diversity modifies the association between the risk factors and vulvodynia or is altered as a consequence of the associations.

Features of the Vaginal and Vestibular Microbioma in Patients With Vestibulodynia: A Case-Control Study.

OBJECTIVE: Our objective was to determine the role of vaginal and/or vestibular microbiota disturbance as an associated factor of symptom characteristic of provoked vestibulodynia (PVD). STUDY DESIGN: In an observational case-control study, the bacterial microbiomes in the vagina and vestibule from 20 women with PVD and 18 healthy controls were compared using a 16S rRNA gene-based molecular analysis. Clinical data were recorded through a 0- to 10-point visual analog scale related to dyspareunia and vulvovaginal pain/burning. RESULTS: Comparative assessment of the bacterial taxa (cutoff ≥15%) revealed 105 genera in the vaginal samples of PVD patients and 113 genera in the vestibular samples. Similarly, 120 genera were detected in the vaginal samples and 151 in the vestibular samples of the control group. Bacterial complexity was higher in the vestibular samples than in vaginal samples in both groups, without statistically significant differences. The following 3 dominant taxonomic units were found: Lactobacillus, Gardnerella, and Atopobium in PVD patients and Lactobacillus, Gardnerella, and Bifidobacterium in the control group. Lactobacillus gasseri was dominant only in women with PVD, showing a significant correlation with burning/pain intensity and dyspareunia severity (0.255 and 0.357, respectively, p < .001). CONCLUSIONS: Our data suggest that bacterial communities in vaginal discharge are an important contributor to the vestibular microbiota. Lactobacillus gasseri may be an element of vulnerability toward the development of vaginal dysbiosis. We can postulate its association as a potential etiologic organism in some individuals, either by itself or in some combination with other trigger factors.

Abnormal vaginal microbioma is associated with severity of localized provoked vulvodynia. Role of aerobic vaginitis and Candida in the pathogenesis of vulvodynia.

Localized provoked vulvodynia (LPV) causes introital dyspareunia in up to 14% of premenopausal women. Vaginal infections like candidosis may play a initiating role. The aim of this study was to test a possible association of vaginal microbiota alternations such as Candida vaginitis (CV), aerobic vaginitis (AV) and bacterial vaginosis (BV) with severity of vulvodynia and painful intercourse. In an observational study, Q-tip touch test (score 1 (no pain) to 10 (worst possible pain)) was performed on seven vestibular locations in 231 LPV patients presenting in the Vulvovaginal Disease Clinics in Tienen, Leuven and Antwerp, Belgium. Severity of pain upon attempting sexual intercourse was recorded in a similar scale. Both scales were compared to results from fresh wet mount phase contrast microscopy on vaginal fluid smears tested for abnormal vaginal flora (AVF), BV, AV and CV according the standardized microscopy method (Femicare). Fisher's exact test was used. Average age was 31.3 ± 11.6 years, and 58.8% (n = 132) had secondary vestibulodynia. There was an inverse relation between the presence of Candida in the vaginal smears and pain score (p = 0.03). There was no relation of pain score, nor Q-tip score with BV. LPV patients with Q-tip score above 7 at 5 and/or 7 o'clock or at 1 and/or 11 o'clock had more often AV than women with lower pain scores (30 vs 14.5%, p = 0.01, and 39 vs 14.7%, p < 0.005, respectively). Detailed study of the vaginal microflora in patients demonstrates that the most severe patients suffer more from AV and less from Candida. These abnormalities need to be actively looked for and corrected before considering surgery or other therapies.

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.

Vulvodynia and fungal association: a preliminary report.

Vulvodynia (vulvar pain syndrome) is a chronic multifactorial disease affecting almost 13 million women in the USA and can lead to morbidity and a reduced quality of life. We hypothesize that an initial microbiological insult in the vagina causes modifications in the biological vaginal milieu and/or an alteration on the lactobacilli flora. The vaginal milieu responds to the insult by developing an inflammatory reaction with abnormal cytokine production. These hypotheses were tested quantifying vaginal lactobacillus and cytokines, in patients with vulvodynia compared to matched healthy controls. Our preliminary data suggest a vaginal flora alteration and an immunological response involving Candida in patients with vulvodynia. Ongoing studies will assist us to clarify these findings.

Repeated vulvovaginal fungal infections cause persistent pain in a mouse model of vulvodynia.

Provoked vestibulodynia, the most common form of vulvodynia (unexplained pain of the vulva), is a prevalent, idiopathic pain disorder associated with a history of recurrent candidiasis (yeast infections). It is characterized by vulvar allodynia (painful hypersensitivity to touch) and hyperinnervation. We tested whether repeated, localized exposure of the vulva to a common fungal pathogen can lead to the development of chronic pain. A subset of female mice subjected to recurrent Candida albicans infection developed mechanical allodynia localized to the vulva. The mice with allodynia also exhibited hyperinnervation with peptidergic nociceptor and sympathetic fibers (as indicated by increased protein gene product 9.5, calcitonin gene-related peptide, and vesicular monoamine transporter 2 immunoreactivity in the vaginal epithelium). Long-lasting behavioral allodynia in a subset of mice was also observed after a single, extended Candida infection, as well as after repeated vulvar (but not hind paw) inflammation induced with zymosan, a mixture of fungal antigens. The hypersensitivity and hyperinnervation were both present at least 3 weeks after the resolution of infection and inflammation. Our data show that infection can cause persistent pain long after its resolution and that recurrent yeast infection replicates important features of human provoked vulvodynia in the mouse.