【作者】 郭栋；

【导师】 朱维铭； 黎介寿；

【作者基本信息】 南京大学 ， 外科学， 2015， 博士

【摘要】 研究背景克罗恩病(Crohn’s disease,CD)是一种发病机制不明确,无法治愈的慢性特异性炎症性肠病。目前普遍认为易感人群与肠道菌群不恰当的炎症反应导致CD的发生发展,CD与菌群的关系成为了研究热点。临床实践中,EEN(exclusive enteral nutrition,EEN)的作用日益突出,诱导及维持CD缓解、纠正营养不良、不良反应少等优势越来越得到关注。EEN诱导以及维持CD缓解的机制仍然不明确。研究证实EEN治疗CD过程中可以影响肠道菌群的组成及功能,但具体改变仍未明确。研究目的本研究拟通过对比本地区CD患者与健康人群的差异和观察EEN诱导和维持CD时对肠道菌群的影响,分析对比肠道菌群在治疗过程主要成分、菌群组成、特定菌种和多样性的变化,探究EEN诱导维持CD缓解与肠道菌群的关系,以揭示EEN诱导CD缓解的机制。研究方法及结果在克罗恩病患者与健康人群肠道菌群对比的研究中,我们采集14名未经治疗的CD患者与10名健康志愿者的粪便标本,提取基因组DNA,采用16SrDNA测序法研究肠道菌群变化。研究结果提示CD患者和健康人群间肠道菌群存在显著差异:菌群主成分存在直观区别;菌群组成存在差异;特定菌种存在差异;CD患者肠道菌群多样性显著低于健康人群。本研究结果研究提供详实数据描述本地区CD患者和健康人群肠道菌群的特征,与其它欧美国家研究结果对比,CD菌群异常存在地区差异性。在单一肠内营养和糖皮质激素诱导克罗恩病缓解对肠道菌群影响的研究中,入选CD患者经过随机分组后,分别给以EEN和糖皮质激素诱导缓解,然后对比治疗前后粪便菌群的改变。研究结果说明糖皮质激素和EEN都具有良好的诱导缓解效果,激素改善炎症指标效果明显,而EEN则对营养指标改善更加显著。EEN和激素治疗后,肠道菌群多样性具有增加的趋势,但是对肠道菌群物种及组成产生截然不同的作用,对特定菌种也产生不同的影响。激素诱导CD缓解时,对肠道菌群的产生更大的影响。EEN诱导CD缓解的过程能够改变肠道菌群比例,增加菌群多样性,使其趋于健康人群;这或许是EEN诱导CD缓解机制之一。在单一肠内营养和糖皮质激素诱导克罗恩病缓解对肠道菌群影响的研究中,待EEN诱导缓解后,我们继续随访接受EEN诱导缓解的患者,随访3个月内及时行粪便采集和临床效果评价。研究证实EEN在维持CD缓解取得良好的临床效果,能够维持疾病缓解,降低炎症指标和改善营养状态。对比EEN诱导和维持CD对菌群影响时,发现EEN在维持CD缓解时对菌群产生的影响较小。EEN维持缓解时过程中,患者整体肠道菌群在菌群物种组成和菌群多样性均得以改善,趋于健康人群。研究结论CD患者与健康人群比较,其肠道菌群在组成和多样性上存在显著差异,且具有地区特异性。糖皮质激素和EEN均够有效诱导CD缓解;均能提高菌群多样性,但对特定菌群物种的影响存在显著不同,且激素治疗对菌群改变更加显著。EEN能够有效维持CD缓解,同时降低炎症因子和改善营养状态。EEN在诱导和维持CD过程中,肠道菌群组分改善,多样性增加,趋于健康人群,这可能是EEN诱导CD缓解机制之一。更多还原

【Abstract】 BackgroundCrohn’s disease(CD)is a idiopathic,chronic,incurable inflammatory disorder.It’s exact etiology is unknown,and both heredity and exposure to bacteria have been implicated.The relationship between gut microflora and host is being widely investigated.Exclusive enteral nutrition bring satisfactory clinical outcome in treatment of CD.EEN can effectively induce and maintain remission for CD,while the mechanism is unclear.Previous studies proved that EEN can change the microbial composition and improve function of gut microflora,while the further illumination is deficiency.PurposeThis study aim to compare the characteristic of gut microbiota between CD patients and healthy control.When applying EEN in inducing and maintaining therapy for CD,we investigated the impact of EEN on gut microflora dynamically and continuously and revealed the exact change of gut microflora after EEN therapy.Methods and resultsIn comparison of gut microflora between CD patients and healthy control,we collected stool sample from 10 healthy control and 14 treatment-naive CD patients,and analyzed microflora through sequencing the V4 region of 16sDNA.We found remarkable difference in flora composition,specific bacteria between CD patients and healthy control,and flora diversity of CD patients decrease strikingly.Combined with studies from western country,we found there is regional features of gut microflora of CD patients.When comparing the impact of EEN with corticosteroid on gut microflora in induction treatment of CD,we enrolled 10 CD patients for each group and 8 patients for each group achieved remission.Both corticosteroid and EEN achieved satisfactory clinical effect.The results suggested that both corticosteroid and EEN change the flora composition dramatically and improve the flora diversity.For certain flora group and specific specie,corticosteroid and EEN play opposite roles.In contrastive analysis with our last study,the composition and proportion of gut microflora had a tendency to be normalized like healthy control.We followed up 6 CD patients who received EEN maintenance treatment after EEN induction treatment,stool was sampled and clinical effect was evaluated at follow-up point punctually.After 3 month follow-up,we found EEN can maintain remission effectively.The disease activity was well controlled,and the inflammatory indicators decreased,and the nutritional status was improved.We found EEN have a tender effect on the change of gut microflora in maintenance therapy than in induction therapy.After EEN maintenance remission treatment,the composition and proportion of gut microflora tended to be normalized continuously,and the flora diversity increased gradually.ConclusionThe gut microflora of CD patients varies from healthy control dramatically in flora composition and proportion specific bacteria;the diversity significantly decrease.Both EEN and corticosteroid can induce active disease into remission effectively.Although both corticosteroid and EEN changed the gut microflora and improved the diversity,corticosteroid act stronger,and for certain flora group and specific specie,corticosteroid and EEN have opposite role.No matter EEN is applied for induction therapy or maintenance therapy,EEN can normalize the disorder composition and proportion of gut microflora continuously,and increase the flora diversity.This is maybe one of mechanism for EEN to induce and maintain CD remission.更多还原