ANALYSIS OF THE LIPIDS OF NORMAL AND GAUCHER BONE-MARROW

Quantitative chemical shift magnetic resonance imaging (QCSI) is curre ntly being utilized for measuring the extent of bone marrow involvemen t and its response to enzyme replacement therapy in patients with Gauc her's disease. Quantitation of the major lipid species in human bone m arrow is required to accurately interpret QCSI data on bone marrow com position. The major lipid species in bone marrow specimens from normal individuals and from patients with type 1 Gaucher's disease were anal yzed by thin-layer and high-pressure liquid chromatography. In normal marrow (N = 5), triglycerides were by far the most abundant lipid (278 +/- 70 mg/gm wet wt), with other non-polar lipids and phospholipids t otaling less than 20 mg/gm wet weight.-The concentration of glucocereb roside in normal marrow was 0.061 +/- 0.06 mg/gm wet weight. Gaucher m arrow (N = 9) had dramatically lower triglyceride levels (51 +/- 53 mg /gm wet wt), and as expected, it had markedly elevated levels of gluco cerebroside (7.1 +/- 3.4 mg/gm wet wt). The other major non-polar lipi ds and phospholipids were measured in selected specimens, but none wer e found that differed so profoundly between normal and Gaucher's disea se. These data support a model of bone marrow alteration in Gaucher's disease in which triglyceride rich adipocytes are progressively replac ed by storage cells, leading to an overall reduction in total lipid co ntent. This phenomenon provides an explanation for the changes in prot on signal intensity observed in QCSI studies of Gaucher bone marrow.