ABSTRACT
1. The dyslipoproteinemia commonly occurring in the hepatosplenic forms of schistosomiasis mansoni in Brazilian patients is characterized by low plasma levels of cholesteryl esters and of the cholesterol-esterifying enzyme, lecithin:cholesterol acyltransferase (LCATase, EC.2.3.1.43). 2. In the present study, normal healthy individuals and patients suffering from hepatosplenic schistosomiasis mansoni were compared for the fatty acyl compositions of circulating plasma cholesteryl esters and of those formed in vitro by the action of LCATase on a) the endogenous plasma lipoproteins and b) an excess of lipoprotein substrate composed of heat-inactivated plasma. 3. In patient plasma the proportions of saturated and monounsaturated cholesteryl esters were higher and those of diunsaturated and polyunsaturated esters were lower than in the control group. 4. Similar differences were observed between patients and controls in the proportions of the cholesteryl ester subclasses formed in vitro by the action of LCATase on endogenous plasma lipoproteins. 5. Incubation of fresh normal or patient plasma with excess heat-inactivated plasma as substrate for LCATase produced proportions of cholesteryl ester subclasses similar to those formed during incubation of nonheated aliquots of the appropriate substrate plasma. 6. We conclude that the alterations in fatty acyl composition of plasma cholesteryl esters in patients with hepatosplenic schistosomiasis mansoni do not appear to be a direct consequence of the low levels of LCATase activity in patient plasma.
Subject(s)
Cholesterol Esters/blood , Liver Diseases, Parasitic/blood , Phosphatidylcholine-Sterol O-Acyltransferase/metabolism , Schistosomiasis mansoni/blood , Splenic Diseases/blood , Adult , Carbon Radioisotopes/metabolism , Female , Humans , MaleABSTRACT
1. The dyslipoproteinemia commonly occurring in the hepatosplenic forms of schistosomiais mansoni in Brazilian patients is characterized by low plasma levels of choleteryl esters and of the cholesterol-esterifying enzyme, lecithin:cholesterol acyltransferase (LCATase, EC.2.3.1.43). 2. In the present study, normal helathy individual and patients sufferin from hepatosplenic schistosomiasis mansoni were comapred for the fatty acyl compositons of circulating plasma cholesteryl esters and of those formed in vitro by the action of LCATase on a) the endogenous plasma lipoprotins and b) an excess of lipoprotein substrate composed of heat-inactivated plasma. 3. In patient palsma the proportions of saturated and monounsaturated cholesteryl esters were higher and those of diunsaturated and polyunsaturated esters were lower than in the control group. 4. Similar differences were observed between patients and controls in the proportions of the cholesteryl ester subclasses formed in vitro by the action of LCATase on endogenous plasma lipoprotins. 5. Incubation of fresh normal or patient plasma with escess heat-inactivated plasma as substrate for LCATase produced proportions of cholesteryl ester subclasses similar to those formed dduring incubation of nonheated aliquots of the appropriate plasma. 6. We conclude that the alterations in fatty acyl composition of palsma cholesteryl estes in patients with hepatosplenic schistosomiasis mansoni do not appear to be direct consequence of the low levels of LCATase acivity in patient plasma
Subject(s)
Adult , Humans , Male , Female , Cholesterol Esters/blood , Fatty Acids , Phosphatidylcholine-Sterol O-Acyltransferase/metabolism , Schistosomiasis mansoni/blood , Splenic Diseases/blood , Sterol O-AcyltransferaseABSTRACT
During prolonged fasting in lizard and rat, plasma levels of unesterified cholesterol (UC) and phospholipids (TPL) decreased and there were reductions and increases, respectively, in the molar ratios of lecithin (PC) to sphingomyelin (SPH) and UC to TPL. Plasma lecithin: cholesterol acyltransferase (LCATase) activity in lizard and rat plasma was reduced during prolonged fasting. Erythrocyte lipid composition for fasted animals was also characterized by a reduction in the molar ratio PC/SPH and an increase in UC/TPL, and in both species there were positive correlations between these molar ratios in red cells and those in plasma. In both species these were changes in the morphology of the erythrocytes, and those from fasted rats showed alterations in osmotic fragility and permeability which correlated with alterations in lipid composition. These results suggest that changes in plasma lipoprotein lipid composition, linked to reduced LCATase activity, may cause similar alterations in the lipid composition of red cell membranes leading to altered membrane properties.
