Chronic kidney disease, uremic toxins and microbiota

Chronic kidney disease (CKD) is a progressive condition that is associated with a number of serious cardiovascular comorbidities. These are caused by the accumulation of uremic retention solutes (URSs) such as protein-bound uremic toxins, which include indoxyl sulfate, p-cresyl sulfate and trimethylamine-N-oxide. These toxins are metabolized from dietary precursors by the gut microbiota and liver enzymes. Elevated levels of uremic toxins intensify renal and cardiovascular tissue damage by augmenting oxidative stress and inflammation, culminating in adverse outcomes such as atherosclerosis, fibrosis and endothelial dysfunction. Kidney transplantation has been demonstrated to normalize these URS levels, thereby underscoring the pivotal role of renal function in the clearance of these toxins. Conversely, alterations in the composition of the gut microbiota may provide a potential avenue for the reduction of uremic toxin levels and the associated complications. In this review, studies from the 2020 to 2024 period were examined, and the microbiota taxa that are particularly relevant to uremic toxin production were grouped. In addition, their roles in the pathophysiology of CKD were addressed, thereby underscoring the significance of the gut–kidney axis. In the study, the taxa that have attracted attention in studies conducted in the relevant years were discussed separately according to their phylum, family, genus and species.