Background:Portal hypertensive gastropathy(PHG)is a disease characterized by mucosal vascular congestion and mucosal edema in the gastric mucosa of patients with portal hypertension.Although portal hypertension is considered to be the initiating factor of PHG,there is no significant rank correlation between portal venous pressure and PHG severity,suggesting that there may be other influencing factors in the development of PHG.The dysbiosis of gastric microbiota is related to the occurrence and development of various gastric diseases,what’s more,the gastric microbiota exhibits different characteristics in different pathophysiological states.The characteristics of gastric microbiota in cirrhotic patients with portal hypertension have not been reported so far.TIPS can significantly reduce portal pressure by establishing a portosystemic shunt in the liver,which can improve the mucosal characteristics of PHG,however,the effect of TIPS on the gastric microbiota in cirrhotic patients with portal hypertension has not been reported yet.Objective:1.To analyze the characteristics,influence factors and related clinical parameters of gastric microbiota in cirrhotic patients with portal hypertension.2.To investigate the effect of transjugular intrahepatic portosystemic shunt on the characteristics of gastric microbiota in cirrhotic patients with portal hypertension.Methods:Gastric mucosa and gastric juice samples were collected from patients’pre-operation and at 1-month post-operation.The total DNA from the patient specimens was extracted using a DNA rapid extraction kit,and then amplified by 16S r RNA to construct a paired-end(PE)library.Based on Illumina’s Nova Seq PE250 platform,high-throughput sequencing was performed.Finally,bioinformatics analysis was performed on the sequencing results.Results:1.Characteristics of gastric microbiota in cirrhotic patients with portal hypertensionIn cirrhotic patients with portal hypertension,Proteobacteria,Acidobacteria and Chloroflexi were enriched in gastric mucosa,while Firmicutes and Fusobacteria were enriched in gastric juice.The Chao1 index of gastric mucosa in cirrhotic patients with portal hypertension was significantly higher than that of gastric fluid(P<0.01),however,there was no significant difference in Shannon index between them(P>0.05).PCo A analysis showed that there was statistical difference in community composition between gastric mucosa and gastric juice(P<0.05).Further analysis of the gastric microbiota in patients with portal hypertensive gastropathy(PHG)showed that Peptostreptococcus and Capnocytophaga were enriched in gastric mucosa of PHG patients.There was no significant difference inαdiversity andβdiversity of gastric mucosal flora between PHG and non-PHG patients(P>0.05).RDA analysis showed that PPG was the main factor affecting the structural changes of gastric mucosa flora(r~2=0.683,P<0.001).Hamadaea and Eikenella abundance in gastric mucosa of cirrhotic patients with portal hypertension were positively correlated with PPG(r=0.633,0.618,respectively;P<0.01).2.Effects of transjugular intrahepatic portosystemic shunt on the characteristics of gastric microbiota in cirrhotic patientsThere was no significant change in theαdiversity andβdiversity of mucosal microbiota,however,the Chao1 index of gastric juice flora after operation was higher than that before operation(P=0.03).PCo A exhibited different cluster in gastric juice before and after TIPS.The relative abundance of dominant taxa at phylum and genus levels in gastric mucosa didn’t show a marked change,while the gastric juice-dominant taxa changed significantly.In light of LDA results,only two taxa that enriched in gastric mucosa before TIPS were Streptococcus and Alloprevotella,while Streptococcus,Prevotella_7 and Prevotella were abundant in preoperative juice with statistical significance.Bradyrhizobium,Vibrionimonas,and Methylovirgula were significantly enriched in postoperative juice.RDA showed that portal pressure gradient(PPG)was the major factor affecting the structural changes of gastric mucosa and gastric juice microbiota(r~2=0.578,0.319,respectively;P<0.001).Spearman rank correlation analysis showed that Eikenella and Mycoplasma abundance in gastric mucosa of patients before and after TIPS were positively correlated with PPG(r=0.593,0.553,respectively;P<0.001).Conclusions:1.The flora structure between gastric mucosa and gastric juice in cirrhotic patients with portal hypertension is different,but there is no significant difference in the diversity of species between them.2.The composition of gastric mucosal flora in patients with PHG has characteristic changes,Peptostreptococcus and Capnocytophagaare enriched in the gastric mucosa of PHG patients,suggesting that gastric flora may play a role in the occurrence of PHG.3.The major factor affecting the structural changes of gastric mucosal flora in cirrhotic patients with portal hypertension is PPG,what’s more,the relative abundance of Eikenella in gastric mucosa of cirrhotic patients is a significantly correlated with PPG,suggesting that gastric flora may be a potential biomarker of portal hypertension in liver cirrhosis.4.Oropharyngeal flora,such as Streptococcus,Alloprevotella and Prevotella,were more abundant in the stomach of cirrhotic patients with portal hypertension before TIPS,suggesting that portal hypertension may cause gastric bacteria disorder,while TIPS may be beneficial to improve gastric microecological dysbiosis by relieving portal hypertension,which in turn may have an impact on portal hypertension-related complications. |