Alteration of the gut microbiota by vinegar is associated with amelioration of hyperoxaluria-induced kidney injury

Hyperoxaluria is well known to cause renal injury and end-stage kidney disease. Previous studies suggested that the renal function of rats with hyperoxaluria was improved after dietary vinegar intake. However, its underlying mechanisms remain largely unknown. The aim of the present study was to examine changes of gut microbiota and blood and urinary metabolites that associate with changes in kidney function to identify mechanisms involved with vinegar induced amelioration of hyperoxaluria-induced kidney injury. Using an ethylene glycol (EG)-induced hyperoxaluria rat model, we evaluated the effects of the vinegar on renal injury. Oral administration of vinegar (2ml/kg per day) reduced the elevated serum creatinine, BUN, and protected against hyperoxaluria-induced renal injury, renal fibrosis, and inflammation. Gut microbiome analysis of 16S rRNA genes in the hyperoxaluria-induced renal injury rats showed that vinegar treatment altered their microbial composition, especially the recovery of the levels of the Prevotella, Ruminiclostridium, Alistipes and Paenalcaligenes genus, which were significantly increased in the hyperoxaluria-induced renal injury rats. Additionally, liquid chromatography–mass spectrometry (LC-MS)-based metabolome analysis showed that total of 35 serum and 42 urine metabolites were identified to be associated with protective effects of vinegar on hyperoxaluria-induced renal injury rats. Most of these metabolites were involved in thiamine metabolism, glycerol phosphate shuttle, biotin metabolism, phosphatidylcholine biosynthesis and membrane lipid metabolism. Importantly, the effects of vinegar against renal injury were weakened after depletion of gut microbiota by antibiotic treatment. These results suggest that vinegar treatment ameliorates the hyperoxaluria-induced renal injury by improving the gut microbiota and metabolomic profiles.