Identifying therapeutic targets for vulvodynia

描述（由申请人提供）：美国估计有600万女性患有外阴痛。诱发性前庭痛通常与外阴前庭炎有关， 最常见于绝经前妇女。这种慢性疼痛综合征的特征是通常位于后前庭的伤害感受器轴突数量增加。临床证据表明，生殖激素影响外阴前庭炎综合征（VVS）的发展和严重程度。除了手术切除神经支配过度的组织外，没有有效的治疗方法。本申请提出了临床前研究，旨在表征VVS的动物模型，并使用它来评估可能适合于治疗靶向的生物学机制。 我们开发了一种VVS大鼠模型，该模型复制了人类的许多临床发现。小体积注射完全弗氏佐剂到大鼠后前庭引起持续的超敏反应和神经支配过度。在Aim 1中，我们使用该模型来研究前庭炎症的神经后果，包括发芽和表型改变。我们将研究神经支配过度的持续性及其与机械前庭敏感性的相关性，并确定我们的模型是否表现出与性交困难一致的行为。我们将评估雌激素是否改变了伤害感受器神经支配的正常模式，也影响了神经支配过度的发展。我们将建立在初步的研究结果，孕激素给药的幼年大鼠感觉神经支配密度的持续增加，并确定这是否增加前庭hypernerveduction的发展。我们将评估我们的模型模拟人类细胞学变化的程度，通过比较大鼠与VVS患者组织切除的结果。 在目的2中，我们测试的假设，血管紧张素II受体2型（AT 2）的激活介导的VVS的神经支配和超敏反应。在初步的研究中，我们表明，AT 2阻断废除我们的模型中的神经支配和超敏反应。我们假设炎症细胞产生局部的肾素-血管紧张素系统，合成血管紧张素II，从而启动感觉轴突发芽。我们将确定血管紧张素II是否由大鼠和人类前庭组织合成，并使用外植体培养，它是否促进发芽。我们将在我们的大鼠模型中确定在没有炎症诱发发芽和超敏反应的情况下的iAT 2活化。我们将确定AT 2拮抗作用是否不仅能预防，而且能逆转神经支配过度和超敏反应。我们将确定AT 2阻断是否能克服由生殖激素作用增强的神经支配过度和机械敏感性。 这个应用程序将提供在正常和发炎的前庭组织的神经支配调节机制的基本信息。它采用了一种新的大鼠模型，以确定前庭炎性超敏反应的生物学基础，目的是操纵一个关键的信号通路，以确定新的治疗靶点VVS。这些研究中获得的信息有很大的潜力，可以实质性地改变我们对某些形式外阴痛的管理的想法和临床方法。

DESCRIPTION (provided by applicant): An estimated 6 million women in the US suffer from vulvodynia. Provoked vestibulodynia, which typically is associated with vulvar vestibulitis, occurs most often in premenopausal women. This chronic pain syndrome is characterized by increased numbers of nociceptor axons usually localized to the posterior vestibule. Clinical evidence suggests that reproductive hormones influence the development and severity of vulvar vestibulitis syndrome (VVS). Aside from surgical excision of the hyperinnervated tissue, there are no effective therapies. This application proposes preclinical studies designed to characterize an animal model of VVS, and to use it to assess biological mechanisms that may be amenable to therapeutic targeting. We developed a rat model of VVS that replicates many clinical findings in humans. Small-volume injections of complete Freund's adjuvant into the rat posterior vestibule evoke persistent hypersensitivity and hyperinnervation. In Aim1, we use this model to investigate neural consequences of vestibular inflammation, including sprouting and phenotype alterations. We will investigate the persistence of hyperinnervation and its correlation to mechanical vestibular sensitivity, and determine if our model shows behavior consistent with dyspareunia. We will assess whether estrogen, which alters normal patterns of nociceptor innervation, also affects development of hyperinnervation. We will build on preliminary findings that progesterone administered to juvenile rats causes persistent increases in sensory innervation density, and determine whether this augments development of vestibular hyperinnervation. We will assess the extent to which our model simulates human cytological changes by comparing findings in rats with tissue excised from patients with VVS. In Aim 2, we test the hypothesis that activation of the angiotensin II receptor type 2 (AT2) mediates hyperinnervation and hypersensitivity in VVS. In preliminary studies, we show that AT2 blockade abrogates hyperinnervation and hypersensitivity in our model. We hypothesize that inflammatory cells create a local renin-angiotensin system that synthesizes angiotensin II, which initiates sensory axon sprouting. We will determine if angiotensin II is synthesized by rat and human vestibular tissue, and using explant cultures, that it elicits sprouting. We will determine i AT2 activation in the absence of inflammation elicits sprouting and hypersensitivity in our rat model. We will determine if AT2 antagonism not only prevents, but also reverses hyperinnervation and hypersensitivity. We will determine if AT2 blockade is overcomes hyperinnervation and mechanical sensitivity augmented by the actions of reproductive hormones. This application will provide fundamental information on mechanisms that regulate innervation in normal and inflamed vestibular tissue. It employs a novel rat model to identify the biological underpinnings of vestibular inflammatory hypersensitivity with the intention of manipulating a key signaling pathway in order to identify new therapeutic targets in VVS. Information obtained in these studies has strong potential to substantively change our thinking and clinical approach to the management of some forms of vulvodynia.