急性重症胰腺炎患者肠黏膜屏障功能与TLR9及T细胞亚群的关系

Relationship between intestinal mucosal barrier function and TLR9 expression and T cell subsets in patients with acute severe pancreatitis

背景肠黏膜屏障功能在急性重症胰腺炎(severe acute pancreatitis,SAP)患者病情进展中具有重要作用,而在此过程中,免疫抑制与免疫失衡可能导致或加重肠黏膜屏障功能异常,但免疫功能各因子与肠黏膜屏障功能之间的具体关系尚未清晰.目的探讨急性SAP患者的肠黏膜屏障功能与TLR9以及T细胞亚群的关系.方法前瞻性的选取本院2018-01/2020-01期间52例经确诊为SAP患者的临床资料,检测其第1、2、3、7天的血浆内毒素、D-乳酸水平、尿乳果糖/甘露醇(L/M)值并收集TLR9水平、炎症指标[白细胞(white blood cell,WBC),C-反应蛋白(C-reactive protein,CRP),原降钙素(procalcitonin,PCT)]及T细胞亚群(CD3+、CD4+、CD8+百分比),设置健康组比较其与SAP组患者TLR9水平差异,分别分析SAP患者肠黏膜屏障功能与TLR9及T细胞亚群指标表达水平的相关性.结果SAP外周血细菌DNA分析,52例患者细菌阳性率82.69%,共87条DNA条带,17种细菌,以大肠杆菌、凝结芽孢杆菌占比最高,分别为38.89%、33.33%;患者炎症指标WBC、CRP、PCT经测量后显示,WBC、CRP随时间增加而下降,PCT在第1-3天上升,第7天下降,P<0.05;SAP患者血清TLR9水平相对于健康组较高,且在治疗后第2-3天内有所上升,在3 d后参数下降;内毒素、L/M值与D-乳酸能很好地反映患者肠黏膜屏障受损的程度,指标在3 d后均低于2 d时测量值,TLR9与内毒素呈正相关(r=0.792)、与L/M值呈正相关(r=0.668)、与D-乳酸呈正相关(r=0.535),P<0.05;SAP患者体内的T细胞亚群表达水平有所不同,CD3+、CD4+水平随着时间呈现上升趋势,CD8+在第2~3天稍下降,3 d后稍上升,总体呈现下降趋势;T细胞亚群与肠黏膜屏障受损存在相关性,内毒素与CD3+相关性显著(r=0.680)、与CD4+相关性显著(r=0.612)、与CD8+相关性显著(r=0.595);L/M值与CD3+相关性显著(r=0.585),与CD4+相关性显著(r=0.570)、与CD8+相关性显著(r=0.534);D-乳酸与CD3+相关性显著(r=0.515),与CD4+相关性显著(r=0.586),与CD8+相关性显著(r=0.510).结论SAP患者血清中的TLR9水平可以反映其病情变化,指数升高预示患者肠黏膜屏障受损程度,两者之间存在正相关,可以作为今后临床判断SAP患者肠黏膜屏障受损伤的参考依据;且肠黏膜损伤与T细胞亚群的相关性显著,预示抑制T细胞亚群是SAP患者的保护性免疫指标.

BACKGROUND The dysfunction of the intestinal mucosal barrier plays an important role in the progression of severe acute pancreatitis(SAP),and immunosuppression and immune imbalance can lead to or exacerbate intestinal barrier dysfunction in this process.However,the relationship between various immune function factors and intestinal barrier function has not been characterized.AIM To explore the relationship between intestinal mucosal barrier function and TLR9 and T cell subsets in patients with SAP.METHODS The clinical data of 52 patients with SAP diagnosed at our hospital were prospectively selected from January 2018 to January 2020.Plasma endotoxin and D-lactic acid levels,and urine lactulose/mannose(L/M)were detected on the first,second,third,and seventh days.Data on TLR9 levels,inflammation indicators[white blood cells(WBCs),C-reactive protein(CRP),and procalcitonin(PCT)],and T cell subsets(CD3+,CD4+,and CD8+T cell percentages)were collected.A healthy control group was also included to compare their TLR9 levels with those of SAP patients.The correlation between the intestinal mucosal barrier function and the expression levels of TLR9 and T cell subsets in SAP patients was analyzed.RESULTS According to DNA analysis of peripheral blood bacteria,the positive rate of bacteria in the 52 patients was 82.69%,including 87 DNA bands and 17 bacteria.Escherichia coli and Bacillus coagulans accounted for the highest proportions(38.89%and 33.33%,respectively).The measurement of WBCs,CRP,and PCT in patients showed that WBC and CRP decreased with time,while PCT increased on the 1st to 3rd days,and decreased on the 7th day(P<0.05).Serum TLR9 level was higher in SAP patients than in the healthy group,and it rose within 2-3 d after treatment,and decreased after 3 d.Endotoxin,L/M value,and D-lactic acid can well reflect the damage of the intestinal mucosa of patients.The degree of barrier damage after 3 d was lower than the measured value at 2 d.TLR9 was positively correlated with endotoxin(r=0.792),L/M value(r=0.668),and D-lactic acid(r=0.535,P<0.05).In SAP patients,the expression levels of T cell subgroups were different.The levels of CD3+and CD4+T cells showed an upward trend over time.CD8+T cells declined slightly on the 2nd to 3rd days,and rose slightly after 3 d,showing a downward trend overall.There was a correlation between endotoxin and CD3+(r=0.680),CD4+(r=0.612),and CD8+T cells(r=0.595).The L/M value was significantly correlated with CD3+(r=0.680,r=0.585),CD4+(r=0.570),and CD8+T cells(r=0.534).D-lactic acid was also significantly correlated with CD3+(r=0.515),CD4+(r=0.586),and CD8+T cells(r=0.510).CONCLUSION Serum level of TLR9 of SAP patients can reflect the changes in their conditions.The increase in serum TLR9 level indicates the degree of damage to the intestinal mucosal barrier of the patients,and there is a positive correlation between them,suggesting that serum level of TLR9 can be used as a indicator for clinical judgment of the injury of the intestinal mucosal barrier in SAP patients.The correlation between mucosal injury and T cell subsets is significant,which indicates that the suppression of T cell subsets is a protective immune index for SAP patients.