The differential effects of calcium starvation on Duchenne muscular dystrophy fibroblasts

The effects of nutrient deprivation on normal and Duchenne muscular dystrophy fibroblasts were examined. The requirements for Ca2+ and fetal bovine serum were assessed by their effects on the cells' ability to support viral replication, and by ability of the cells to divide in the presence of low levels of these nutrients. When grown in Ca2+-deficient media, Duchenne fibroblasts supported viral replication at a rate 2- to 2.5-fold greater than did normal fibroblasts. At normal Ca2+ levels, Duchenne fibroblasts supported viral replication at levels slightly lower than their normal counterparts. After 48 hr in medium containing 0.2 mM Ca2+, the growth of normal cells was arrested, while Duchenne fibroblasts were relatively unaffected. When grown in medium containing either 0.2 or 2.0% serum, the growth of normal cells was arrested within 48 hr, with cell death occurring within 72 hr. Duchenne fibroblasts continued to divide at these serum levels for 72 hr, reaching higher cell densities than normal cells. These results suggest that a defect related to Ca2+ metabolism may be part of the Duchenne phenotype, which could be used to identify Duchenne muscular dystrophy cells.