Abstract: Objective To analyze the changes of the levels of Bacteroides, Bifidobacterium, Lactobacillus, Akkermansia and Enterococcus in the intestinal flora of elderly patients with chronic kidney disease (CKD), and their correlations with the serum levels of rich leucine alpha-2 glycoprotein 1 (LRG1), suppressor of cytokine signaling 3 (SOCS-3), and thioredoxin-interacting protein (TXNIP). Methods A total of 200 elderly patients admitted to Qinhuangdao Hospital of Peking University Third Hospital from January 2022 to June 2024 were enrolled as the CKD group. Meantime, 85 volunteers who underwent health check-up were selected as the control group. The screening medium was used to detect the levels of Bacteroides, Bifidobacterium, Lactobacillus, Akkermansia, and Enterococcus. Enzyme-Linked Immuno Sorbent Assay kits were used to detect the serum levels of LRG1, SOCS-3, and TXNIP. Pearson correlation analysis was used to analyze the relationships between the intestinal flora and serum LRG1, SOCS-3 and TXNIP. The multiple logistic regression model was used to analyze the influencing factors for CKD in the elderly. Results Compared with the control group, the CKD group had higher levels of urinary protein, cystatin C, blood creatinine, blood urea nitrogen, LRG1, and TXNIP, and lower levels of hemoglobin, estimated glomerular filtration rate (eGFR) and SOCS-3 (P<0.01). In elderly CKD patients, the serum levels of LRG1 and TXNIP were negatively correlated with the levels of Bacteroides, Bifidobacterium, Lactobacillus, and Akkermannella, and positively correlated with the level of Enterococcus (all P<0.01); SOCS-3 level was positively correlated with the levels of Bacteroides, Bifidobacterium, Lactobacillus, and Akkermannella, and negatively correlated with the level of Enterococcus (all P<0.01). Multivariate logistic regression analysis revealed that cystatin C, eGFR, Bacteroides, Bifidobacterium, Lactobacillus, Akkermannella, Enterococcus, LRG1, SOCS-3, and TXNIP were significant risk factors for CKD occurrence in older adults (P<0.05). Conclusions The levels of Bacteroides, Bifidobacterium, Lactobacillus, Akkermannella, Enterococcus, as well as LRRG1, SOCS-3, and TXNIP are abnormally expressed in elderly patients with CKD. These serum indicators show correlations with gut microbiota and are all influencing factors of the occurrence of CKD.

Key words: chronic kidney disease, intestinal flora, leucine rich alpha-2 glycoprotein 1, suppressor of cytokine signaling 3, thioredoxin-interacting protein