Decrease in Free Cystine Content of Cultured Cystinotic Fibroblasts by Ascorbic Acid

Abstract
The 100-fold increase in free cystine content characteristic of cultured skin fibroblasts from patients with nephropathic cystinosis was decreased more than 50 percent by addition of L-ascorbic acid to the culture medium at concentrations of 0.29 to 2.9 millimolar. Fresh ascorbic acid must be added to the culture medium daily to produce a progressive decrease of the free cystine content of the cells over a 3-day period. Upon removal of ascorbic acid from the medium, the free cystine content returns to its initial value.