Indoxyl Sulfate (potassium salt)

Indoxyl sulfate is a metabolite of tryptophan derived from dietary protein. Tryptophan is metabolized by intestinal bacteria into indole, which is absorbed into the blood and then further metabolized to indoxyl sulfate in the liver, which is normally excreted in urine. In chronic kidney disease patients where renal function is compromised, indoxyl sulfate can accumulate in serum as a uremic toxin, inducing oxidative stress and accelerating progression of the disease. Indoxyl sulfate at 250 µM can induce the activation of NF-kappaB, promoting the expression of both TGF-beta1 and Smad3 expression in proximal tubular cells of rats, which is associated with profibrotic activity.