Elevated serum levels of indoxyl sulfate, p-cresyl sulfate, and phenylacetylglutamine are consistently associated with declining kidney function in diabetic kidney disease and promote renal injury through the induction of oxidative stress, inflammation, and fibrosis via activation of NADPH oxidase and NF-κB pathways.

Bacteria in the gut break down protein from food into toxic chemicals that enter the blood. When the kidneys fail, these toxins build up and enter kidney cells, where they turn on enzymes that produce harmful reactive molecules. These molecules trigger a chain reaction that turns on inflammatory signals and causes scar tissue to form, damaging the kidney over time.