In rats, chronic indoxyl sulfate treatment modeling patients with chronic kidney disease resulted in behavioral alterations and impairments in spatial memory and locomotor activity.90 Controversially, indoxyl sulfate, indolepropionic acid, and indole-3-aldehyde modulated astrocyte activation and suppressed CNS inflammation both in vitro and in vivo in an experimental autoimmune encephalomyelitis mouse model of multiple sclerosis.32,91 Furthermore, AhR was also activated by indoxyl sulfate in human astrocytes followed by a decrease in proinflammatory gene expression. The gene discussed is AHR; the disease is multiple sclerosis.