Lipid substrates for LCAT activity in liver disease

Plasma polyunsaturated fatty acids in liver cirrhosis with or without chronic hepatic encephalopathy: a preliminary study

Fatty acid levels (from C14:0 to C22:6n3) in plasma lipid fractions were prospectively studied in 11 cirrhotic patients with chronic hepatic encephalopathy and compared with those in 23 cirrhotic patients without chronic hepatic encephalopathy with similar age, sex distribution, and liver and nutritional status, and in 11 age- and sex-matched, healthy subjects. Plasma lipid fractions were separated by thin-layer chromatography and fatty acids were identified by capillary column gas-liquid chromatography. Total n6 polyunsaturated fatty acid plasma levels were lower in cirrhotic patients--with and without chronic hepatic encephalopathy--than in control subjects. In addition, arachidonic acid levels, both in total lipids and fractions, were lower in patients with than in those without chronic encephalopathy. On the other hand, a selective decrease of plasma docosahexaenoic acid (a major component of neuronal membranes) was observed in those patients with chronic encephalopathy as compared with both control and cirrhotic subjects without chronic encephalopathy. These findings may be due to various mechanisms. Differences in long-chain polyunsaturated fatty acid content in fish- and meat-restricted diets partly may account for these findings. However, it could be speculated that polyunsaturated fatty acid biosynthesis may be reduced further in patients with chronic hepatic encephalopathy because of either a decrease in portal essential fatty acid extraction in the postabsorptive phase due to portal-systemic shunting or to the effect of protein-restricted diets. Furthermore, the finding of low plasma docosahexaenoic acid in these patients raises the possibility that this deficiency might be an additional pathogenic factor in chronic hepatic encephalopathy.

Fatty acid composition of adipose tissue in patients with chronic liver disease

In this study plasma free fatty acids and adipose tissue fatty acid composition in 10 cirrhotic patients, 5 patients with non-cirrhotic chronic liver disease and in 5 controls have been investigated. Fatty acid composition of adipose tissue in cirrhotic patients demonstrated a significant increase of 16:1 and a decrease of 18:2. Monounsaturated fatty acids represented the major fraction both in cirrhotic patients (57.5%) and in controls (55.2%). Polyunsaturated fatty acids were significantly lower in cirrhotic patients (9.1%) than in controls (14.3%). In plasma, total free fatty acids were higher in cirrhotics (732 +/- 111 microM) than in controls (319 +/- 38 microM; mean +/- SE) and the individual fatty acid profile showed a prevalence of monounsaturated fatty acid (increase of 16:1 and 18:1 and decrease of 16:0 and 18:0). The decrease in polyunsaturated fatty acids in the composition of adipose tissue triglycerides could represent a marker of long-term reduction in lipid absorption, intake and/or enhanced lipid consumption. The resemblance between plasma and adipose tissue pattern in cirrhotic patients supports the hypothesis that increased lipolysis in such patients plays the most important role in influencing plasma free fatty acid composition.

Membrane lipid composition of red blood cells in liver disease: regression of spur cell anaemia after infusion of polyunsaturated phosphatidylcholine

The morphology of red blood cells was studied in 30 patients with severe liver cirrhosis, in 10 patients with extrahepatic jaundice, and in 10 control subjects. In all the patients with extrahepatic jaundice more than 30% of red blood cells were target cells with increased resistance to osmotic lysis. In 12 patients with liver cirrhosis more than 30% of red blood cells were spur cells. The cholesterol: phospholipids (C/PL) molar ratio was 0.89 in target cells, 1.33 in spur cells, and 0.74 in normal red blood cells. The red blood cell membrane cholesterol and phospholipids exchanged with plasma lipoproteins, the lipid composition of which was studied in eight patients with spur cells; the free cholesterol: phospholipid (FC/PL) molar ratio was 0.33 (0.16 in the controls) in high density lipoproteins (HDL) and 1.40 (0.82 in the controls) in low density lipoproteins (LDL); in these patients the polyunsaturated fatty acid content was low in both phospholipids and cholesterol esters of lipoproteins. The irregular folds of the spur cells regressed when polyunsaturated lecithin was infused (2 g daily for five days) in eight patients with spur cell anaemia; the infusions decreased both C/PL ratio in RC to 0.88 and the concentration of unconjugated bilirubin (104.3 to 82.0 mumol/l (6.1 to 4.8 mg%)), whereas the activity of the plasma lecithin:cholesterol acyltransferase (LCAT) increased from 31.2 to 54.4 mumol/l/h. Polyunsaturated fatty acid content of RC lecithin increased after the infusion as it did in HDL, the FC/PL ratio of which decreased to 0.23.