Increased lipase activity in erythrocytes of patients with hereditary spherocytosis (Minkowski-Chauffard syndrome)

The membrane of human erythrocytes contains a lipase (I), the physiological role of which is still unknown. However, we show here that there is a difference in lipase activity in erythrocytes from control subjects and from patients with the Minkowski-Chauffard syndrome. Blood (five volumes) from fasted subjects was collected into tubes containing three volumes of an anticoagulant solution (0.47 g of citric acid, 1.33 g of sodium citrate, and 3 g of dextrose in 100 mL of distilled water), immediately cooled on ice, and centrifuged at 4 #{176}C. The plasma was discarded and the erythrocytes were washed four times at 4 #{176}C with isotonic saline, to eliminate the leukocytes and platelets. Subjects studied were 19 controls, four patients with hemolytic anemias [including one with Zieve syndrome, one autoimmune anemia, one cirrhosis, and one anemia caused by a deficiency in glutathione reductase (EC 1.6.4.2)], and five patients with Minkowski-Chauffard syndrome. Lipase activity was measured by incubating 50 1zL of erythrocytes with 100 nmol of unlabeled triolein and glyceryl tri[I-”C]oleate (4 X 106 cpm per mmol) at pH 7 with Triton X100, to hemolyze as previously described (1). The free fatty acids were separated from other lipids by thin-layer chromatography, scraped off the plates, and the radioactivity was measured. Lipase activity was expressed in nanomoles of free fatty acids released per hour per milliliter of cells. The mean erythrocyte lipase activity in the controls was 95 nmol/h per milliliter (Table 1), a result similar to that for erythrocytes of patients with other types of hemolytic anemia (85 nmol/h per milliliter). In contrast, erythrocyte lipase activity in cells from the five patients with Minkowski-Chauffard anemia was higher, 290 nmol/h per milliliter. The primary cause of the MinkowControls 95 6019 132 Various hemolytic 85 604 anemias 122 Minkowski-Chauf290 2055 fard syndrome 405