Localized Provoked Vulvodynia: Association With Nerve Growth Factor and Transient Receptor Potential Vanilloid Type 1 Genes Polymorphisms.

OBJECTIVE: The aim of the study was to study the associations between localized provoked vulvodynia (LPV) and several single-nucleotide polymorphisms (SNPs) in the transient receptor potential vanilloid type 1 (TRPV1), nerve growth factor (NGF), and the heparanase (HPSE) genes. MATERIALS AND METHODS: Prevalence of SNPs among 65 women with moderate or severe primary LPV (initial symptoms occur with first provoking physical contact) and 126 healthy, ethnically matched controls was analyzed in an observational case-control study. Each participant answered a questionnaire addressing familial LPV occurrence and comorbid pain conditions. RESULTS: Familial occurrences of LPV, temporomandibular joint (TMJ) symptoms, recurrent vaginitis, and irritable bowel syndrome were significantly higher among LPV women than healthy controls. Genotyping analyses revealed a novel, statistically significant high prevalence of polymorphism c.945G>C (rs222747) of TRPV1 and a SNP in the promoter region of NGF (rs11102930) in LPV women compared with controls. A logistic regression model for rs222747 and rs11102930 frequent alleles indicates significant LPV association within the entire study group and Ashkenazi Jewish women, respectively. Comparison of pain conditions with frequent alleles showed the rs222747 "CC" genotype of TRPV1 associated with women with TMJ, recurrent vaginitis, and LPV. CONCLUSIONS: Our results suggest novel genetic susceptibility to primary LPV associated with specific alleles in genes TRPV1 and NGF and propose the rs222747 "C" allele of TRPV1 as a common genetic predisposition for other pain syndromes.

Topical nifedipine for the treatment of localized provoked vulvodynia: a placebo-controlled study.

UNLABELLED: Topical application of the calcium antagonist nifedipine has demonstrated effectiveness in treating chronic anal fissure, without adverse effects. Like chronic anal fissure, vulvodynia is associated with muscle hypertonicity and an inflammatory infiltrate. We conducted a double-blind placebo-controlled study to investigate the effectiveness of 2 concentrations of topical nifedipine cream in the treatment of vulvodynia. Thirty participants were alternately assigned to 3 topical treatment groups: .2% nifedipine, .4% nifedipine, and placebo. All administered the cream to the vestibule 4 times daily for 6 weeks. For all 3 treatment groups, mean pain intensity on vestibular touch, assessed by the Q-tipped cotton test, pain from speculum insertion, and reports of pain during sexual intercourse was reduced at post-treatment compared with pre-treatment. These improvements remained at 3 months' follow-up. The effectiveness of nifedipine in treating vulvodynia did not exceed that of placebo. PERSPECTIVE: The topical application of both nifedipine and a placebo reduced pain in women with vulvodynia. This study highlights the need for controlled trials of treatments for vulvodynia and raises doubts about studies conducted without comparison to placebo.