Early Diagnosis Of Crohn's Disease And Changes Of Gut Microbiota

Part ?: Follow-up of ileocecal inflammatory lesions and its significance in early diagnosis of Crohn's diseaseBackground and purpose: Crohn's disease(CD)is a chronic inflammatory disease of gastrointestinal tract with unknown etiology.Its clinical manifestations are complex and varied.The course of disease is progressive destruction with recurrent attacks and strong disability.In recent years,the incidence of CD in China is on the rise and the disease burden is getting increasingly heavier.There is no specific symptoms and signs in the early stage of CD.At present,no clear early diagnostic standard and effective diagnostic marker exists.Most patients can only obtain clinical diagnosis when they have typical manifestations of CD,at which they have often entered the advanced stage with complications and poor prognosis.Early diagnosis is helpful to seize the opportunity window of CD treatment,to reduce intestinal injury and to prevent disability,thus improving prognosis.Studies have found that prospective follow-up or screening of individuals at or near the biological onset period,especially the first-degree relatives of CD patients,can obtain relevant information about the natural course of CD and realize early diagnosis.However,the positive family history of CD patients in China is only 1.2%,which makes it difficult to carry out early diagnosis research through this method.In addition,there are reports that drawing lessons from the experience of opportunistic screening for colorectal cancer and screening people at risk of CD is expected to become an effective method for early diagnosis of CD.In this part,through prospective follow-up of patients with ileocecal inflammatory lesions of unknown causes,it is aimed at understanding the characteristics of early lesions of CD patients in China and provide clues for clinical early diagnosis.Methods: From January 2013 to December 2018,at Department of Gastroenterology,Seventh Medical Center of PLA General Hospital,232 with unexplained ileocecal inflammatory lesions under colonoscopy examination were enrolled,which the patients were followed up for more than one year.The clinical,endoscopic,histopathological,laboratory and imaging examinations of the patients were evaluated to clarify the diagnosis of the disease,and various clinical evaluation indexes of early CD,nonspecific enteritis and intestinal tuberculosis were statistically analyzed.Results: Among the 232 patients,155 were males and 77 were females,the age of first diagnosis was(43.9 ± 13.8)years old.The follow-up period was 27 months(12 ? 79 months).Early CD was diagnosed in 29 cases(12.5%),intestinal tuberculosis in 45 cases(19.4%),nonspecific enteritis in 105 cases(45.3%),and no definite diagnosis in 53 cases(22.8%).29 patients with early CD had abdominal symptoms,accounting for 16.9%(29/172)of 172 patients with ileoceccal inflammation with abdominal symptoms.In early CD patients,the proportion of patients with abdominal pain,elevated C-reactive protein(CRP)level and elevated erythrocyte sedimentation rate(ESR),anti-saccharomyces cerevisiae(ASCA)positive rate,positive rate of tuberculosis infection T cells and percentage of patients with thickened intestinal wall were all higher than those in patients with non-specific enteritis(62.1%,18/29 vs.33.3%,35/105;13.8%,4/29 vs.0;13.8%,4/29 vs.1.0%,1/105;24.1%,7/29 vs.1.0%,1/105;20.7%,6/29 vs.3.8%,4/105;95.7%,22/23 vs.0),and the proportion of patients with no abdominal symptoms was lower than that of patients with non-specific enteritis(0 vs.31.4%,33/105).The differences were statistically significant(x2=6.692,Fisher exact prohability method,x2=7.162,17.826,7.497,Fisher exact prohability method,and Fisher exact prohability method,all P <0.05).Eearly CD patients were more likely to have multiple lesion sites(55.2%,16/29),and mainly deep ulcers(55.2%,16/29)and ulcers with a long diameter of 5 to 10 mm(39.3%,11/28).The lesions of non-specific enteritis were mostly confined to the end of ileum(75.2%,79/105),and were mainly superficial ulcers(41.0%,43/105)and ulcers with a long diameter less than 5 mm(69.0%,49/71).The proportion of patients withot abdominal symptoms and the positive rate of tuberculosis infection of T cells spot test of early CD patients were both lower than those of intestinal tuberculosis group(0 vs.15.6%,7/45 and 20.7%,6/29 vs.68.9%,31/45).The positive rate of ASCA and the proportion of patients with thickened intestinal wall were higher than those of intestinal tuberculosis group(24.1%,7/29 vs.0 and 95.7%,22/23 vs.11/19),and the difference was statistically significant(Fisher exact prohability method,x2=13.713,Fisher exact prohability method and x2=6.710,all P < 0.05).The results of Multivariate binary logistic regression analysis showed that abdominal pain and positive ASCA were independent risk factors for early CD(odds rated(OR)=2.855,95% confidence interval(CI)1.014 to 8.037,P=0.047;OR=10.033,95% CI 2.274 to 44.250,P=0.002).Conclusion: Long-term follow-up for patients with ileocecal inflammatory lesions of unknown causes could effectively identify and diagnose CD in the early stage.Abdominal pain and positive serum ASCA at initial diagnosis were independent risk factors for early diagnosis of CD.Ileocecal inflammatory lesions with abdominal symptoms were one of the early manifestations of CD.Symptomatically ileocecal inflammatory lesions were one of the early manifestations of CD.However,asymptomatically ileocecal inflammatory lesions seldom progressed to CD,follow-up observation was sufficient.Part ?: Changes of gut microbiota in patients with early Crohn's diseaseBackground and purpose: Studies have shown that gut microbiota plays an important role in the pathogenesis of CD.There are obvious gut microbiota imbalance in CD patients.Fecal microbiota markers can be used to distinguish CD from non-CD or active phase CD from remission phase CD,in possession of potential value in diagnosing and monitoring disease activity.Researches on the correlation between gut microbiota and CD is currently a hot research topic,but most of them focus on gut microbiota imbalance and the pathogenesis,disease activity,postoperative recurrence and therapeutic response of CD,while the research on gut microbiota related to early CD has not been reported.In this part,the dynamic changes of gut microbiota in different stages of the natural course of CD was studied,laying a foundation for further research on early diagnosis of CD related microbiota biomarkers.Methods: From December 2017 to October 2019,20 patients with early CD and 20 patients with advanced CD confirmed in the Department of Digestive Internal Medicine of the Seventh Medical Center of The General Hospital of the People's Liberation Army(PLAGH)were included,and 30 age-matched healthy controls were included.The diversity,composition,abundance and difference of fecal microbiota of subjects were analyzed through 16 S rDNA high-throughput sequencing,and the metabolic function of the community was predicted.Results: Alpha diversity analysis showed that there was no significant difference in Alpha diversity in early CD group compared with control group and advanced stage;Compared with the control group,there was significant difference in Alpha diversity in advanced CD group(P<0.05).PCoA analysis showed that beta diversity in early CD group and advanced CD group were all significantly different from that in control group(all P<0.05);Compared with advanced CD group,there was no difference in Beta diversity in early CD group.Results of species classification and abundance analysis showed that the abundance of Bacteroidetes in the early CD group increased compared with the control group at the phylum classification level;Compared with the early group,the abundance of Proteobacteria and Fusobacteria in the advanced CD group increased.At the genus level,compared with the healthy control group,the abundance of Bacteroides,Prevotella,Lachnospiracea?incertae?sedis,Phascolarctobacterium and Parabacteroides in the early CD group increased.Compared with the early CD group,the abundance of Escherichia/Shigella,Klebsiella,Clostridium XIVa and Fusobacterium in the advanced CD group increased.Results of significant difference analysis showed that compared with the control group,the abundance of Bacteroides,Parabacteroides and Enterococcus in the early CD group increased significantly,while the abundance of Ruminococcus 2,Gemmiger,Faecalibacterium,Clostridium 4,Butyricicoccus and Dorea decreased.Compared with the early CD group,the abundance of Escherichia/Shigella and Proteus in the advanced CD group were significantly increased,while the abundance of Roseburia,Lachnospiracea?incertae?sedis,Blautia,Fusobacterium,Bacteroides,Parabacteroides and Anaerostipes in the advanced CD group was decreased.Conclusion: The results of this study showed that compared with the healthy control group,the gut microbiota structure of early CD patients was significantly out of balance,with significantly increased abundance of Bacteroidetes while significantly reduced Firmicutes.At the genus level,the abundance of Bacteroides,Parabacteroides and Enterococcus in the early CD group increased significantly,while the abundance of Coprococcus,Ruminococcus2,Clostridium 4,Butyricicoccus and Dorea decreased.Compared with the early CD group,Escherichia/Shigella and Proteus in the advanced CD group were obviously enriched.Bacteroides,Parabacteroides,Enterococcus,Escherichia/Shigella and Proteus had certain significance as specific biomarkers for early diagnosis or prediction of CD disease progression,which were worthy of further study.