Comparisons of the composition of fat cells obtained from the marrow of normal individuals or of subjects with aplastic anemia and from bone marrow cultures.

The lipid composition of fat cells in the bone marrow of normal individuals and patients with aplastic anemia was investigated, using thin-layer and gas-liquid chromatography. The results were compared to those obtained from fat cells grown in vitro. Thin-layer chromatography (t.l.c) revealed that triacylglycerols were the major component of normal and aplastic marrow fat cells and of fat cells in culture. Analysis by gas-liquid chromatography (g.l.c) of the triacylglycerols, diacylglycerols, and nonesterified fatty acids detected minor differences between fat cells from normal and aplastic marrow. Although there were no statistically significant differences in the proportions of saturated fatty acids and their unsaturated analogues, the relative amounts of gamma-linolenic acid were increased in aplastic anemia and those of linoleic and myristoleic acids were reduced. In contrast, fat cells obtained from in vitro cultures contained a much higher proportion of unsaturated fatty acids. These findings indicate that there is no marked abnormality in the composition of bone marrow fat cells in aplastic anemia, but that minor differences can be detected; the fatty acid composition of bone marrow fat cells is not reproduced in vitro.