Lipoprotein lipase activity in lipomatous tissue, post-
heparin lipoprotein lipase activity in plasma, and the composition and concentration of serum
lipoproteins were studied in 15 patients with
Multiple Symmetric Lipomatosis (MSL). Extremely elevated
lipoprotein lipase activity in adipose tissue was found in MSL patients. Total and hepatic post-
heparin plasma lipolytic activity was normal, while a moderate but statistically significant increase of extrahepatic lipolytic activity was present. An abnormal composition of serum
lipoproteins, characterized by a significant increase in
high density lipoproteins, namely HDL2 subfraction, and
apoprotein A-I, was demonstrated. A concomitant decrease in and abnormal composition of
low density lipoproteins were found. This
lipoprotein pattern is consistent with a newly recognized type of
hyperalphalipoproteinemia. Significant correlations were found between serum
HDL2 cholesterol values and
lipoprotein lipase activity in adipose tissue (as well as between serum
VLDL-triglyceride and
HDL2 cholesterol values). These observations confirm the role of adipose tissue
lipoprotein lipase in
triglyceride-rich
lipoprotein catabolism. The elevated levels of
lipoprotein lipase activity in adipose tissue, in addition to a previously demonstrated decrease in
adrenergic-stimulated lipid mobilization, could account for both the abnormal fat accumulation in lipomatous fat cell and for
hyperalphalipoproteinemia in MSL patients. The occurrence of MSL in two brothers suggests an inherited enzymatic defect, indicating MSL as a "
triglyceride storage disease in adipose tissue".