Lesions in the Skin, Intestine, and Central Nervous System Induced by an Antimetabolite of Niacin

In 1986, a study was conducted on newborn mice to understand the effects of 6-aminonicotinamide (6-AN), an antagonist of niacin, which is known to cause pellagra in humans. Pellagra is characterized by dermatitis, diarrhea, and dementia. The mice were given a single intraperitoneal injection of 6-AN (50 mg/kg body weight) and developed lesions in the skin, intestinal tract, and central nervous system. Notably, there was a delay in hair growth, with the first microscopic abnormality being a vacuolar change in the hair follicles on post-injection Day 3. By Day 5, hyperkeratosis and irregular acanthosis were observed. In the central nervous system, neuronal chromatolysis was observed in anterior horn cells in the spinal cord and motor neurons in the brain. While the pathologic features of these 6-AN-treated mice may not be exactly identical to those of human pellagra, the study suggested that this experimental model could help elucidate possible mechanisms in the development of pellagra lesions.