Effect And Potential Mechanism Of Fecal Microbiota Transplantation In Treatment Of Chronic Hepatitis B

Background:Chronic hepatitis B(CHB)is a chronic liver disease caused by the persistent infection of hepatitis B virus(HBV).It refers to those who have been tested positive for hepatitis B virus,who have disease more than six months,or whose onset date is unclear but have clinical manifestations of chronic hepatitis.Clinical manifestations are usually fatigue,anorexia,nausea,bloating,liver pain and other symptoms.It is reported that there are approximately 240 million people with chronic hepatitis B all over the world,most of them die from complications caused by it.15%-40% of patients with chronic hepatitis B will develop cirrhosis,liver failure,and hepatocellular carcinoma(HCC).The persistent hepatitis B virus infection and its complications have added a large economic burden to a large number of families and also brought health threats.The immune mechanism of acute or chronic infection caused by hepatitis B virus(HBV),even the development of cirrhosis or hepatocellular carcinoma is still unclear.More and more studies have shown that the composition of intestinal flora of chronic hepatitis B patients and the normal population is significantly different,and the intestinal flora plays an important role in the development of chronic hepatitis B.At present,the common antiviral drugs are mainly nucleoside(acid)analogs and interferons.Although they can block the progress of the disease and prevent the risk of cirrhosis,liver cancer,death,etc.,they are difficult to cure hepatitis B and completely remove hepatitis B virus.Therefore,seeking effective treatment methods is an urgent problem in this field.Based on the close association between intestinal flora and chronic liver disease,it is particularly important to rebuild normal intestinal microorganisms to treat chronic hepatitis B.Fecal microbiota transplantation(FMT)is a method of introducing a fecal suspension of healthy people into the patient's intestine through a nasogastric tube or nasal duodenum tube,gastroscopy or colonoscopy,rectal catheter enema,etc.Adjust and restore the normal intestinal flora to achieve the purpose of treating certain diseases.More and more research shows that FMT has been used to treat Clostridium difficile infection,IBD,IBS and various liver diseases.As currently recognized as the most promising treatment to reconstruct the structure of the intestinal flora,FMT has been used more in intestinal diseases,but there have been fewer studies on chronic liver disease,especially HBV-related chronic liver disease.A thorough study of the role and mechanism of FMT in the treatment of chronic hepatitis B will provide new targets for the prevention and treatment of chronic HBV infection.Objective:To investigate the effects and potential mechanism of fecal microbiota transplantation(FMT)in treatment of chronic hepatitis B(CHB).METHODS:A total of 50 C57/BL mice(6 to 8 weeks old)were divided into 5 groups: control group,CHB group,entecavir(EG)group,comprehensive treatment(EFMT)group,and blocker(EFMT-TAK)group.The mice in each group were given corresponding treatment.The general condition of the mice was observed daily,and fecal specimens were kept every 10 d.The mice were sacrificed after 12 weeks,and the liver tissues and blood samples of the mice were collected.HE staining was used for histological scoring.HBs Ag and IL-18 levels were measured by ELISA.TLR4 expression was detected by flow cytometry.Intestinal flora diversity was analyzed by high-throughput sequencing.RESULTS:(1)Compared with control group,the body weight of mice in the CHB group was significantly reduced(P<0.05).The body weight loss of the mice in EG group,EFMT group,and EFMT-TAK group was reversed to some extent as compared with CHB group(P<0.05).(2)The histological score of the mice in CHB group was significantly higher than control group(P<0.05).The score in EG group was lower than that in CHB group(P<0.05).The scores in EFMT group and EFMT-TAK group were lower than those in EG group obviously(P<0.05),and that in EFMT-TAK group had a further downward trend than EFMT group(P<0.05).(3)Compared with control group,the serum level of HBs Ag in the model mice was significantly increased(P<0.05)and decreased after entecavir treatment(P<0.05).The HBs Ag levels in both EFMT group and EFMT-TAK group were more significantly lower than that in EG group(P<0.05).(4)The IL-18 level in CHB group was significantly higher than control group(P<0.05).After entecavir treatment,the IL-18 level was decreased(P<0.05),abd that in Both EFMT group and EFMT-TAK group was decreased more than EG group(P<0.05).(5)TLR4 expression in CHB group was higher than that in control group(P<0.05),that in EG group was lower than CHB group(P<0.05),and that in EFMT group was further decreased(P<0.05).(6)Significant differences in the flora of CHB group was observed as compared with control group.The heat map analysis at the Class level showed that the abundances of Gammaproteobacteria,Deltaproteobacteria and Negativicutes were significantly higher in CHB group than those in normal group.The abundances of Deltaproteobacteria and Negativicutes in EFMT group were closer to those in control group.The heat map analysis at the Family level indicated that Burkholderiaceae,Desulfovibrionaceae and Veillonellaceae in CHB group were significantly higher than those in control group,while in EG group and EFMT group,the above flora were gradually approaching normal.The ? diversity index showed that the diversity index in CHB group was decreased significantly,the diversity in EG group was increased,that in EFMT group was increased further,and the ? diversity in EFMT-TAK group was the highest.CONCLUSION:FMT plays an active role in the treatment of CHB.The mechanism may be related to reducing the level of IL-18 and improving the structure of its intestinal flora.The TLR4 signaling pathway is involved.