Molecular Epidemiology of Recurrent Aphthous Stomatitis: Role of Ghrelin

描述（由申请人提供）：复发性口疮性口炎（RAS）是最常见的口腔黏膜疾病之一。受影响的个体经历复发性口腔溃疡，大小从几毫米到超过1/2英寸不等。RAS病变可能是全身性疾病的表现，也可能发生在表面健康的个体中。RAS病变的周期性、其在第20年的高峰患病率和家族聚类表明，环境、年龄依赖性和遗传因素可能参与其中。尽管在过去的50年里进行了广泛的研究，RAS的发病机制仍然是未知的。因此，目前的治疗大多是姑息性的，对预防长期复发无效。胃饥饿素是近年来发现的一种具有多种功能的肽，包括调节生长、保护胃和抑制炎症细胞因子。我们的研究还表明，影响血浆胃饥饿素的因素与RAS的危险因素重叠。因此，我们假设生长素缺失与RAS发病有关。本研究的总体目的是确定RAS中ghrelin的表达和循环水平是否发生改变。我们将从佛罗里达大学服务的人群中招募参与者。我们将通过问卷调查、检查、血液和唾液测量以及手术活检来收集数据。具体目标1（循环胃饥饿素）：我们将比较60例（30例有活动性溃疡和30例无活动性溃疡）和50例不相关对照的空腹血浆胃饥饿素水平(1)，采用不匹配的病例对照设计；(2)40例在活动性和非活动性阶段的空腹血浆胃饥饿素水平，采用非随机交叉设计。酶联免疫吸附试验（ELISA）数据将在SAS v9.1中使用协方差分析、逻辑回归和配对t检验进行分析。此外，我们将进行二次流行病学分析，比较这些组中与胃饥饿素相关的体征和症状。特异性目标2（胃饥饿素蛋白表达）：我们将进行一项试点研究，通过免疫组织化学比较胃饥饿素和胃饥饿素受体（生长激素促分泌受体GHS-R1a和GHS-R1b）蛋白表达(1)在活跃病例的溃疡组织与对照组的正常组织中，(2)在空腹RAS病例的溃疡组织与非溃疡邻近口腔上皮组织中。特异性目标3（胃饥饿素基因表达）：我们将进行一项试点研究，比较空腹条件下活性RAS患者溃疡和非溃疡邻近组织中胃饥饿素和胃饥饿素受体的基因表达。具体目标4（数据/DNA库）：最后，我们将为未来的遗传流行病学研究提供样本/DNA和流行病学数据，旨在了解个体RAS易感性。这项研究的结果对于提高我们对RAS发病机制的理解至关重要，它们是开发针对特定病因的成功治疗方法的必要步骤。项目描述：本研究的目的是了解复发性口腔炎（RAS，也称为口腔溃疡）的原因，以便在未来的临床试验中开发和测试预防和治疗这种疾病的有效方法。我们特别感兴趣的是了解口腔溃疡患者是否有胃饥饿素（一种新发现的激素，参与生长和保护粘膜免受损伤）的缺陷。

DESCRIPTION (provided by applicant): Recurrent aphthous stomatitis (RAS) is one of the most common and poorly understood oral mucosal disorders. Affected individuals experience recurrent painful oral ulcerations ranging in size from a few mm to over 1/2 inch. RAS lesions may be a manifestation of a systemic disorder or they may occur in apparently healthy individuals. The cyclic nature of RAS lesions, their peak prevalence during the 2nd decade and familial clustering suggest that environmental, age-dependent and genetic factors are likely involved. Despite extensive research over the past five decades, the etiopathogenesis of RAS is still unknown. As a result, current treatments are mostly palliative and ineffective in preventing recurrences long-term. Ghrelin is a recently discovered peptide with multiple functions including regulation of growth, gastroprotection and inhibition of inflammatory cytokines. Our studies also indicate that factors affecting plasma ghrelin overlap with risk factors for RAS. Thus, we hypothesize that a ghrelin deficit is associated with RAS onset. The overall aim of this study is to determine whether ghrelin expression and circulating levels are altered in RAS. We will recruit participants from the population served by the University of Florida. We will collect data through questionnaires, examinations, blood and salivary measurements, and surgical biopsies. Specific Aim 1 (Circulating ghrelin): We will compare fasting total plasma ghrelin levels (1) in 60 cases (30 with and 30 without active ulcers) vs. 50 unrelated controls using an unmatched case-control design and (2) in 40 cases during their active vs. inactive phase using a non-randomized crossover design. Enzyme-linked immunosorbent assay (ELISA) data will be analyzed using analysis of covariance, logistic regression and paired t-tests in SAS v9.1. Additionally, we will perform secondary epidemiologic analyses comparing ghrelin-related signs and symptoms in these groups. Specific Aim 2 (Ghrelin protein expression): We will conduct a pilot study to compare ghrelin and ghrelin receptors (growth hormone secretagogue receptors GHS-R1a and GHS-R1b) protein expression (1) in ulcerated tissue from active cases vs. normal tissue from controls and (2) in ulcerated vs. non-ulcerated adjacent oral epithelial tissue of fasting RAS cases by immunohistochemistry. Specific Aim 3 (Ghrelin gene expression): We will conduct a pilot study to compare ghrelin and ghrelin receptors gene expression in ulcerated vs. non-ulcerated adjacent tissue of active RAS cases under fasting conditions using microarrays. Specific Aim 4 (Data/DNA Bank): Lastly, we will bank samples/DNA and epidemiologic data for future genetic epidemiologic studies aimed at understanding individual RAS susceptibility. The results of this research are crucial to advancing our understanding of RAS etiopathogenesis, and they are a necessary step toward the development of successful treatments targeted at the specific etiologic factor. Project Narrative: The goal of this research is to understand the cause of recurrent aphthous stomatitis (RAS, also known as canker sores) so that effective means of preventing and treating this condition may be developed and tested in future clinical trials. In particular, we are interested in knowing if patients with canker sores have a deficit of ghrelin (a newly discovered hormone involved in growth and mucosal protection from injury).