Low Density Lipoprotein Phospholipids Research Articles

Concentration and composition of serum lipoproteins during a low-fat diet at two levels of polyunsaturated fat.

A 12-week dietary intervention was carried out among 40 families from North Karelia, a county in Finland with an exceptionally high rate of coronary heart disease and high serum cholesterol values. The proportion of dietary energy derived from fat was reduced during the 12-week intervention period from about 39% to 23% in all families. The families were randomly allocated into two groups. Twenty families consumed a diet with a polyunsaturated to saturated fat (P/S) ratio of 0.9 (group I), while the other 20 families had a diet with a P/S ratio of 0.4 (group II). Total serum cholesterol decreased by 16% and 9% in men of groups I and II, respectively, and by 16% in women of both groups. These changes were due to a decrease in both low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol. LDL cholesterol and phospholipid reached minimum values after 6 weeks on both intervention diets, but LDL protein responded more slowly. Thus, after 6 weeks LDL had an altered composition containing less cholesterol and phospholipids and more protein and triglycerides than during the baseline diet. During the intervention, the linoleic acid content in the serum cholesteryl ester fraction increased, and the magnitude of this change correlated negatively with the changes in total and LDL cholesterol. The decrease in HDL cholesterol during the two intervention diets was due to a fall in the HDL2 cholesterol (29% and 24% in men, and 26% and 25% in women in groups I and II, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of postpartum lactation on lipoprotein lipids and apoproteins.

To determine if postpartum lactation alters plasma lipoprotein lipid and apoprotein concentrations and composition, we studied 56 overnight fasting lactating and 16 nonlactating women approximately 6 weeks postpartum. Postpartum results are presented as absolute concentrations and as the difference from antepartum values determined at 36 weeks gestation. Antepartum lipoprotein lipid and apoprotein concentrations were generally not different in the 2 groups, with the single exception of whole plasma and low density lipoprotein (LDL) apoprotein (apo) B (probably a chance difference). When expressed as the antepartum and postpartum difference, the lactating and nonlactating groups were indistinguishable in very low density lipoprotein (VLDL) and LDL triglyceride, cholesterol, phospholipid, and apo B concentrations. However, lactating women had higher high density lipoprotein (HDL) cholesterol, phospholipid, apo A-I, and apo A-II concentrations than nonlactating women when results were expressed as differences from antepartum values or as absolute values. HDL triglyceride concentrations were not significantly different between lactating and nonlactating women by either analysis. There was no significant effect of lactation on VLDL or LDL composition, but there was a significant increase in the percent cholesterol content in HDL. We hypothesize that the increase in HDL constituents in lactation is generated in part by increased catabolism of triglyceride-rich lipoproteins by the lactating breast.

Human plasma lipoproteins and total parenteral nutrition with intravenous fat emulsion.

Lipoprotein concentration and composition before and after Intralipid infusion were investigated in seven adult surgical patients receiving continuous total parenteral nutrition. Plasma samples were obtained prior to parenteral alimentation, after 7 days of glucose/amino acid solution without Intralipid, and again following 5 days of daily Intralipid. Cholesterol, triglyceride, protein, and phospholipid concentrations were determined on very low-, low-, and high-density lipoprotein from each specimen. After Intralipid very low-density lipoprotein concentration fell to 29% (p less than 0.015) of pre-Intralipid levels. There was no substantial increase in low-density lipoprotein phospholipid post-Intralipid to suggest the presence of lipoprotein-X. Plasma total triglyceride levels declined by 33% after Intralipid (p less than 0.01) and plasma total cholesterol levels rose by 40% (p less than 0.02). In our patients, in whom metabolic mechanisms were not saturated, it would appear that Intralipid was metabolized by activated lipoprotein lipase pathways, without the appearance of hyperlipidemia or abnormal lipoproteins.

動脈壁中膜平滑筋細胞におけるLDLリン脂質代謝について(2)

動脈壁中膜平滑筋細胞におけるLDLリン脂質代謝について(2)

Metabolic effects of dietary fiber from dehulled soybeans in humans

The normal diet of six healthy volunteers was supplemented by 21 g of dietary fiber from two different soybean seed fiber preparations, either a nonpurified and never-dried soya pulp A (39% dietary fiber) or a purified soya fiber B (79%), for 3 wk each. Mean daily fecal wet weight was increased by 19 and 38% in the fiber periods A and B as compared to a 2-wk control period (p < 0.05). Stool frequency and transit time remained unchanged. Fecal fiber increased by 52% only during period B. Fecal calcium, magnesium, and iron were increased (p < 0.05), mainly after higher intakes during both fiber periods. Excretion of neutral steroids remained unchanged, but their concentration was lowered (p < 0.05). A 21% increase of fecal bile acids by fiber A was specifically due to deoxycholic acid (+ 32%, p < 0.01). Oral glucose tolerance was slightly improved after period B. Neither fiber changed serum triglycerides, but fiber B increased low-density lipoprotein-cholesterol by 19% (p < 0.01) and low-density lipoprotein-phospholipids by 16% (p < 0.05). The ratio high-density/low-density lipoprotein-cholesterol, however, did not change significantly. Thus, dietary fibers from soybean do not seem to contribute to the hypocholesterolemic effect of soya. The results of this study also demonstrate that two apparently similar dietary fibers, coming from a single source, can exert distinctly different metabolic effects.

動脈壁中膜平滑筋細胞におけるLDLリン脂質代謝について

動脈壁中膜平滑筋細胞におけるLDLリン脂質代謝について

Lipoprotein lipids in renal transplant recipients of different pre-transplant etiology of renal disease A comparison of male and female patients

Serum and lipoprotein lipids have been compared in male and female transplant recipients with glomerulonephritis or analgesic nephropathy as etiology of pre-transplant renal disease, and a number of differences were observed. 1. (1) Serum cholesterol and phospholipid levels were elevated in glomerulonephritis and female analgesic nephropathy, but not in male analgesic nephropathy patients. 2. (2) Glomerulonephritis patients had normal low density lipoprotein (LDL) cholesterol levels whereas these were elevated in female and depressed in male analgesic nephropathy patients. 3. (3) LDL phospholipid, on the other hand, was normal in male and elevated in female transplant recipients irrespective of etiology of pre-transplant renal disease, while high density lipoprotein (HDL) phospholipid levels were elevated in female glomerulonephritis patients only. Mild hypertriglyceridemia and a tendency to increased HDL cholesterol were observed in all patients. These results provide further evidence for the complexity of lipoprotein lipid abnormalities in renal disease.

Age-related changes in cholesterol and bile acid metabolism in rats.

Age-related changes in serum and liver cholesterol, phospholipid and triglyceride levels, serum lipoproteins, biliary secretion of cholesterol, phospholipid and bile acids, and fecal excretion of sterols and bile acids were examined in Sprague-Dawley and Wistar strain male rats, 7 to 106 weeks in age. Serum and liver lipid levels increased with age in both strains but the liver phospholipid level remained unchanged. The proportion of serum alpha-lipoprotein increases and that of beta- and prebeta-lipoproteins slightly decreased. Cholesterol and phospholipids in low density lipoprotein and cholesterol in high density lipoprotein fractions also increased with age. Bile flow and biliary secretion of cholesterol and bile acids decreased in aged rats, but when they were expressed in terms of units per rat they were almost constant without regard to age. Pool size, synthesis, secretion, and turnover frequency of bile acids also did not change when they were expressed per rat, though 7-week-old rats showed a low value for turnover frequency. Biliary secretion of phospholipid, however, increased in aged rats. Biliary secretion of chenodeoxycholic and alpha-muricholic acids decreased but that of cholic and hyodeoxycholic acids increased. Daily excretion of feces and fecal neutral sterols decreases in aged rats but the excretion of bile acids remained constant regardless of age. The ratio of coprostanol and cholesterol in the total sterols was not affected. Fecal lithocholic, beta-muricholic and P10 (probably omega-muricholic) acids were decreased with age but the other bile acid components were not changed or were slightly increased.

THROMBOSIS AND ORAL CONTRACEPTIVES

2 cases of thrombophlebitis of the lower extremity within a short period of 3 months following use of the combined oral contraceptive (Ovral and Voldys) were observed. The 1st patient sought gynecological care on March 30 177 with complaints of pain when walking and swelling of the left leg for the previous 5 days. She had been taking Ovral as a contraceptive measure for the previous 3 months. On local examination there was a swelling of the left leg below the knee joint pitting edema tenderness of calf muscle Hoffmans sign + Ve. The right leg appeared normal. The patient was put on complete bed rest anticoagulants antibiotics and analgesics and she responded to treatment. There had been no previous history suggestive of thrombophlebitis or diabetes. The 2nd case was admitted to the hospital on September 5 1977 with a history of irregular vaginal bleeding for the preceding 6 months. At the time of admission she had been bleeding for 20 days. There was no past history suggestive of thrombophlebitis. Local examination revealed marked swellng of the left leg pitting edema + marked tenderness of calf muscle Hoffmans sign + Ve. She was diagnosed as a case of thrombosis of the deep vein of the leg and was given heparin antibiotics rest and analgesics. The hormones were immediately stopped and the patient responded to treatment. In both patients the oral contraceptive administered had an estrogen content of 50 mg. The mechanism by which thromboembolism occurs during the use of oral contraceptives is unknown. According to the report of the World Health Organization scientific group (1971) increased response to aggregating agent adenosine diphosphate shown by platelets in women on OCs and in patients with manifest occlusive vascular disease is because of an abnormality in phospholipids in low density lipoprotein.