Cholesterol Journal Articles

Record 9941 to 9960

Plasma cholesterol-predictive equations demonstrate that stearic acid is neutral and monounsaturated fatty acids are hypocholesterolemic
Yu, S., J. Derr, et al. (1995), Am J Clin Nutr 61(5): 1129-39.
Abstract: In the present study we used regression analyses to evaluate the effects of stearic acid (18:0) on total cholesterol (TC), low-density-lipoprotein-cholesterol (LDL-C), and high-density-lipoprotein-cholesterol (HDL-C) concentrations (mmol/L). Using data from 18 articles, we developed the following predictive equations (monounsaturated fatty acids, MUFAs; polyunsaturated fatty acids, PUFAs): delta TC = 0.0522 delta 12:0-16:0 - 0.0008 delta 18:0 - 0.0124 delta MUFA - 0.0248 delta PUFA; delta LDL-C = 0.0378 delta 12:0-16:0 + 0.0018 delta 18:0 - 0.0178 delta MUFA - 0.0248 delta PUFA; delta HDL-C = 0.0160 delta 12:0-16:0 - 0.0016 delta 18:0 + 0.0101 delta MUFA + 0.0062 delta PUFA. Our analyses revealed that unlike the other long-chain saturated fatty acids (SFAs), stearic acid had no effect on TC and lipoprotein cholesterol concentrations in men and women. MUFAs elicited an independent hypocholesterolemic effect that we believe is due to the small amount of 12:0-16:0 in the experimental diets evaluated. The observation that stearic acid has unique effects on TC, LDL-C, and HDL-C provides additional compelling evidence that it be distinguished from the other major SFAs in blood cholesterol predictive equations.

Plasma cholesterol-suppressing effect of papain-hydrolyzed pork meat in rats fed hypercholesterolemic diet
Morimatsu, F., M. Ito, et al. (1996), J Nutr Sci Vitaminol (Tokyo) 42(2): 145-53.
Abstract: The effects of papain-hydrolyzed pork meat on plasma and liver cholesterol levels were studied in rats fed a cholesterol-enriched diet. In rats fed the low-molecular-weight fraction of papain-hydrolyzed pork meat, the plasma cholesterol concentration, more particularly the VLDL and LDL cholesterol concentrations, were significantly lower (p < 0.01) than in the rats fed untreated pork meat or soybean protein. Feeding with this fraction rather than with untreated pork meat also led to a significantly lower liver cholesterol concentration (p < 0.01) and increased fecal excretion of neutral and acidic steroids. The low-molecular-weight fraction contained peptides with molecular weights of 3,000 or less and had an amino acid composition similar to that of pork meat itself. This study suggests that peptides produced by papain-hydrolysis of pork meat have a hypocholesterolemic activity through their interference with the steroid absorption process.

Plasma cholesteryl ester transfer and hepatic lipase activity are related to high-density lipoprotein cholesterol in association with insulin resistance in type 2 diabetic and non-diabetic subjects
Riemens, S. C., A. van Tol, et al. (2001), Scand J Clin Lab Invest 61(1): 1-9.
Abstract: We evaluated the hypothesis that plasma cholesteryl ester transfer (CET) and lipase activities are influenced by insulin sensitivity and contribute to the low high-density lipoprotein (HDL) cholesterol observed in type 2 diabetic patients and insulin-resistant non-diabetic subjects. Sixteen type 2 diabetic and 16 non-diabetic subjects participated. Diabetic and non-diabetic subjects were divided in equal groups of eight subjects with low or high insulin sensitivity, which was documented as the glucose infusion rate (M-value) during the last hour of a 3-h euglycaemic hyperinsulinaemic clamp (150 mU kg(-1) h(-1), blood glucose target 4.6 mmol L(-1)). Post-heparin plasma lipoprotein lipase (LPL) and hepatic lipase (HL) activities were measured in samples obtained 1-2 weeks before the clamp. Plasma CET was measured by a radioisotope method. Compared to non-diabetic men with high insulin sensitivity (n = 8) HDL cholesterol was lower in type 2 diabetic men (n=8, p<0.01) and non-diabetic men (n=8, p <0.05) with low insulin sensitivity, and the HDL cholesterylester content was lower in type 2 diabetic men with high insulin sensitivity (n=8, p<0.05). In non-diabetic subjects with high insulin sensitivity, plasma CET was lower than in the other groups (p<0.05 for all). Multiple regression analysis showed that plasma CET (p=0.001) and HL activity (p=0.02) were independently and negatively associated with the M-value. No association between the M-value and LPL activity was observed. Independent negative relationships of HDL cholesterol with plasma CET (p = 0.04) and HL activity (p=0.03) were observed. This study supports the hypothesis that a low HDL cholesterol associated with insulin resistance in type 2 diabetic and non-diabetic subjects is related to a high plasma CET and a high HL activity.

Plasma cholesteryl esters provided by lecithin:cholesterol acyltransferase and acyl-coenzyme a:cholesterol acyltransferase 2 have opposite atherosclerotic potential
Lee, R. G., K. L. Kelley, et al. (2004), Circ Res 95(10): 998-1004.
Abstract: Evidence suggests that ACAT2 is a proatherogenic enzyme that contributes cholesteryl esters (CEs) to apoB-containing lipoproteins, whereas LCAT is an antiatherogenic enzyme that facilitates reverse cholesterol transport by esterifying free cholesterol on HDL particles. We hypothesized that deletion of LCAT and ACAT2 would lead to absence of plasma CEs and reduced atherosclerosis. To test this hypothesis, ACAT2-/- LCAT-/- LDLr-/-, ACAT2-/- LDLr-/-, and LCAT-/- LDLr-/- mice were fed a 0.15% cholesterol diet for 20 weeks. In comparison to LDLr-/- mice, the total plasma cholesterol (TPC) of ACAT2-/- LCAT-/- LDLr-/- mice was 67% lower because of the complete absence of plasma CEs, leading to 94% less CE accumulation in the aorta. In the LCAT-/- LDLr-/- mice, TPC and atherosclerosis were significantly higher because of increased accumulations of ACAT2-derived CE. In ACAT2-/- LDLr-/- mice, again compared with LDLr-/- mice, TPC was 19% lower, whereas atherosclerosis was 88% lower. Therefore, the absence of ACAT2 led to a significant reduction in TPC although benefits in reduction of atherosclerosis were much more pronounced. Overall, the data suggest that ACAT2-derived CE is the predominant atherogenic lipid in blood, and that an important goal for prevention of atherosclerosis is to limit ACAT2-derived CE accumulation in lipoproteins.

Plasma clearance of emulsified triolein in conscious rats: effects of phosphatidylcholine species, cholesterol content and emulsion surface physical state
Clark, S. B., A. Derksen, et al. (1991), Exp Physiol 76(1): 39-52.
Abstract: In vivo clearance of an emulsified triglyceride from rat plasma is strongly influenced by the phosphatidylcholine molecular species and the cholesterol content of the emulsion. Chylomicron-sized, glycerol-tri9,10-3Holeate (triolein)-sonicated emulsions containing 2-3 or 9-14 mol% unesterified cholesterol and specific phosphatidylcholines (egg, dimyristoyl, dipalmitoyl, distearoyl) were prepared above the phospholipid gel----liquid crystalline transition temperatures and injected intravenously into awake, non-fasting rats in bolus doses of 1-3 mg lipid. The emulsified triolein was cleared from plasma both by lipolysis during circulation and by uptake of emulsion particles or their remnants into tissues. Increasing the cholesterol content greatly accelerated particle clearance from plasma when emulsions were made with mixed-chain (egg) phosphatidylcholine, but prolonged their circulation time when the emulsions contained saturated phosphatidylcholines. The relative amounts cleared by reticuloendothelial versus liver parenchymal cells were influenced both by the cholesterol content and the phosphatidylcholine species of the emulsions. Significant triolein lipolysis in plasma occurred only with egg or dimyristoyl phosphatidylcholine emulsions containing 2-3% cholesterol and this lipolysis was blocked by increasing the cholesterol content. No lipolysis occurred when emulsions contained dipalmitoyl or distearoyl phosphatidylcholine, irrespective of cholesterol content.

Plasma electrolytes, total cholesterol, liver enzymes, and selected antioxidant status in protein energy malnutrition
Etukudo, M. H., E. O. Agbedana, et al. (1999), Afr J Med Med Sci 28(1-2): 81-5.
Abstract: Golden and Ramdath proposed the free radical theory of kwashiorkor, suggesting that the changes seen in kwashiorkor may be the result of an imbalance between the production and safe disposal of free radicals. In malnourished children, mineral metabolism and antioxidant status need renewed attention especially in relation to cause and functional significance of the changes in concentration of these substances. In the present study, the modified Wellcome classification was used to classify the protein energy malnourished children into kwashiorkor marasmic-kwashiorkor, marasmus and underweight. Twenty-six healthy and normal children were used as controls. Standard procedures were used for the analyses of the biochemical parameters. Our results showed that plasma total cholesterol, sodium, potassium and bicarbonate, beta-carotene, retinol and uric acid were significantly lower in the malnourished group than the control group (P < 0.05), while transaminases were significantly increased in the malnourished group (P < 0.05). These findings suggest an altered electrolyte and antioxidant status in protein energy malnutrition.

Plasma exchange versus an affinity column for cholesterol reduction
Burgstaler, E. A. and A. A. Pineda (1992), J Clin Apher 7(2): 69-74.
Abstract: The recent introduction of low-density lipoprotein (LDL)/very low-density lipoprotein (VLDL) selective-removal systems offers an alternative to plasma exchange (PE). For the last 10 years, we have treated a male homozygous hypercholesterolemia type IIA patient with PE using 5% normal serum albumin (NSA) replacement, PE using 6% hydroxyethyl starch (HES) replacement, single dextran sulfate cellulose bead affinity column (DSAC) (Kaneka LA-40), and double DSAC. This report compares the performance of these systems in cholesterol reduction (total, LDL+VLDL, and high-density lipoprotein HDL and their effect on the total protein, albumin, and hematocrit levels. The number of procedures and average volume of plasma treated using PE-NSA, PE-HES, 1-DSAC, and 2-DSAC were 113, 64, 15, 90 and 3,939, 3,270, 3,519, and 3,588 ml, respectively. The average pretreatment total cholesterol levels were baseline 864 mg/dL, PE-NSA 606 mg/dL, PE-HES 610 mg/dL, 1-DSAC 467 mg/dL, and 2-DSAC 395 mg/dL with plasma reductions of 59%, 57%, 47%, and 55%, respectively. Average LDL+VLDL plasma reductions were PE-NSA 58%, PE-HES 59% (N = 1), 1-DSAC 46%, and 2-DSAC 56%. Average HDL plasma reductions were PE-NSA 58%, PE-HES 69% (N = 1), 1-DSAC 5%, and 2-DSAC 17%. The average total cholesterol and LDL+VLDL reductions were comparable for both types of PE and the 2-DSAC system. The average HDL loss was 53% lower for the DSAC systems than for PE systems.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma HDL cholesterol concentrations are correlated to bile cholesterol saturation index in the African green monkey
Scobey, M. W., F. L. Johnson, et al. (1991), Am J Med Sci 301(2): 97-101.
Abstract: In an attempt to determine if plasma lipoprotein concentrations correlate with the bile cholesterol saturation index in the African green monkey, we have studied a group of adult male animals available from a long-term study investigating the effects of dietary fat and cholesterol on cholesterol metabolism and atherosclerosis. The animals were fed diets containing 0.8 mg cholesterol/kcal or 0.03 mg cholesterol/kcal for five years. Within each dietary cholesterol group, animals received 42% of dietary calories as fat, enriched with either saturated or polyunsaturated fat. Using stepwise multiple linear regression, high density lipoprotein (HDL) cholesterol concentration was found to be the best plasma lipid predictor of the bile cholesterol saturation index. When the cholesterol saturation index of a fasting gallbladder bile specimen was compared to the plasma HDL cholesterol level for individual animals, a significant positive correlation was noted for animals fed polyunsaturated fat, (r = 0.68) and for animals fed saturated fat (r = 0.72). For any value of HDL cholesterol, however, the cholesterol saturation index was higher in animals fed polyunsaturated fat compared to saturated fat. Since plasma HDL cholesterol levels were positively correlated with the bile cholesterol saturation index in adult male African green monkeys, we conclude that a metabolic link exists between plasma HDL cholesterol concentrations and bile cholesterol saturation, perhaps due to enhanced delivery of cholesterol to the liver by HDL.

Plasma HDL cholesterol, triglycerides, and adiposity. A quantitative genetic test of the conjoint trait hypothesis in the San Antonio Family Heart Study
Mahaney, M. C., J. Blangero, et al. (1995), Circulation 92(11): 3240-8.
Abstract: BACKGROUND: The conjoint trait hypothesis proposes that combined low HDL cholesterol (HDL-C) and high triglyceride (TG) levels represent a single, inherited phenotype that adiposity may influence in an unspecified manner. We conducted formal statistical genetic tests of the conjoint trait hypothesis and the relation of the conjoint trait to adiposity using data for 569 subjects in 25 pedigrees from the San Antonio Family Heart Study. METHODS AND RESULTS: We conducted multivariate genetic analyses to detect the effects of genes and environmental factors on variation in plasma concentrations of HDL-C and TG, fat mass (as percent body weight FM%, determined by bioelectric impedance), and body mass index (BMI). We used maximum-likelihood methods to simultaneously estimate the phenotypic means and SDs, heritabilities (h2), effects of sex, age-by-sex, eight dietary and medical covariates, and genetic and environmental correlations. Likelihood ratio tests disclosed significant heritabilities (P <.001) for all traits (h2HDL-C = 0.55, h2TG = 0.53, h2FM% = 0.37, h2BMI = 0.44) but significant genetic correlations (P <.001), indicating pleiotropy, between two trait pairs only: HDL-C and TG (PG = -0.52) and fat mass and BMI (PG = 0.86). We obtained significant environmental correlations between all trait pairs except HDL-C and BMI (P >.05). CONCLUSIONS: Both shared genes (pleiotropy) and shared environmental factors contribute to the commonly observed inverse phenotypic association between plasma levels of HDL-C and TG. Rather than low HDL-C and high TG being a single, genetically transmissible entity, it is the inverse relation between these two phenotypes throughout their normal ranges of variation as well as at the extremes that is influenced by shared genes and shared environments. However, common environmental factors, not shared genes, account for reported associations of plasma HDL-C and TG levels with measures of adiposity.

Plasma HDL-cholesterol has an effect on nitric oxide production and arachidonic acid metabolism in the platelet membranes of coronary heart disease patients without LDL-hypercholesterolemia
Tretjakovs, P., U. Kalnins, et al. (2000), Med Sci Monit 6(3): 507-11.
Abstract: AIM: To evaluate nitric oxide (NO) production and 3Harachidonic acid (AA) incorporation into platelet membranes of coronary artery disease (CAD) patients with/without HDL-hypocholesterolemia. MATERIAL: 16 healthy controls (C), 14 CAD patients with plasma HDL-hypocholesterolemia (nCAD) and 14--without HDL-hypocholesterolemia (nCAD). All subjects were without peripheral vascular disease and hypertension. The groups were matched for age, sex, BMI. The diagnosis of CAD was substantiated by coronary angiography. METHODS: Nitric oxide end products xNO (NO2- plus NO3-) levels in the platelet membranes were measured using anion-exchange chromatography. 3HAA release from labelled platelets was studied by the method of Neufeld and Majerus; radioactivity was measured by liquid scintillation counting. Levels of plasma HDL-cholesterol (HDL-Ch) and triglycerides were enzymatically determined. RESULTS: Significant increase (mean +/- SD; Mann-Whitney U test) of 3HAA incorporation into platelet membrane phospholipids was noted in CAD patients in comparison with healthy subjects (p < 0.001). A correlation (multiple regression analysis) was established between HDL-C level and 3HAA (r = -0.58, p < 0.05, n = 28); and between HDL-Ch and NOx levels (r = 0.76, p < 0.05, n = 28) in CAD patients. CAD patients had lower NOx than healthy subjects (p < 0.0001), NOx was lower in the group with decreased HDL-Ch concentration (wCAD 36 +/- 5 vs. nCAD 42.3 +/- 6 mumol/mg, p < 0.002). CONCLUSIONS: CAD patients show decreased ability to produce platelet-derived NO that leads to higher platelet sensitivity to aggregating stimuli. Decreased plasma HDL-Ch may affect AA metabolism and NO production in the platelet membranes of CAD patients without LDL-hypercholesterolemia.

Plasma high-density lipoprotein cholesterol but not apolipoprotein A-I is a good correlate of the visceral obesity-insulin resistance dyslipidemic syndrome
Couillard, C., B. Lamarche, et al. (1996), Metabolism 45(7): 882-8.
Abstract: Apolipoprotein (apo) A-I is a major component of high-density lipoproteins (HDLs), and it has been suggested that measurement of apo A-I may provide additional information in the assessment of coronary heart disease (CHD) risk. In the present study in a sample of 111 men (age mean +/- SD, 35.3 +/- 6.6 years), we determined whether a low apo A-I concentration is associated with the cluster of metabolic abnormalities that characterize the visceral obesity-insulin resistance dyslipidemic syndrome. For this purpose, the first and fourth quartiles of apo A-I and HDL cholesterol (HDL-C) concentrations were compared in relation to body fat distribution, glucose tolerance, and plasma insulin and lipoprotein levels. Men in the first quartile (< the 25th percentile) of HDL-C, as compared with men in the fourth quartile (> the 75th percentile), were characterized by an elevated visceral adipose tissue (AT) accumulation (P <.05), as well as by increased plasma levels of triglycerides (TGs P <.0001), apo B (P <.0005), and insulin (P <.01). These differences were not found when the first and fourth quartiles of plasma apo A-I concentrations were compared. These results suggest that plasma levels of HDL-C are more closely associated with the various features of the visceral obesity-insulin resistance syndrome than plasma apo A-I.

Plasma kinetics and uptake by the tumor of a cholesterol-rich microemulsion (LDE) associated to etoposide oleate in patients with ovarian carcinoma
Azevedo, C. H., J. P. Carvalho, et al. (2005), Gynecol Oncol 97(1): 178-82.
Abstract: OBJECTIVES: Previously, we reported that etoposide oleate associated to a cholesterol-rich microemulsion (LDE) is taken up by malignant cells overexpressing low-density lipoprotein (LDL) receptors. The association is stable, preserves antiproliferative activity of the drug, and reduces toxicity to animals. Here, we determined in patients the plasma kinetics of LDE-etoposide oleate and verified whether the complex concentrates in ovarian carcinomas. METHODS: (3)H-etoposide oleate associated to LDE labeled with (14)C-cholesteryl oleate was intravenously injected into four ovarian carcinoma patients (50 +/- 8.7 years) 24 h before surgery. Blood samples were collected over a 24-h period to determine the radioactivity plasma decay curves, and the plasma fractional clearance rate (FCR) was calculated by compartmental analysis. Specimens of tumors and normal ovaries excised during the surgery were collected for lipid extraction and radioactive counting. RESULTS: FCRs of LDE label and of the drug were similar (0.0985 and 0.1722, respectively, P = 0.2422). (14)C-LDE uptake was 4.9 times and (3)H-etoposide oleate uptake was 4.1 times greater in the ovarian tumors than in the contralateral normal ovaries (LDE uptake, in cpm/g = 560 +/- 171 and 146 +/- 59; etoposide oleate uptake = 346 +/- 75 and 103 +/- 56, respectively). CONCLUSIONS: Most of the drug is retained in the microemulsion particles until its removal from the circulation and internalization by the cells. In addition, LDE-etoposide oleate has the ability to concentrate in malignant ovarian tissues. Therefore, the complex may be used to direct and concentrate etoposide oleate in ovarian carcinomas.

Plasma kinetics of a cholesterol-rich emulsion in subjects with or without coronary artery disease
Santos, R. D., W. Hueb, et al. (2003), J Lipid Res 44(3): 464-9.
Abstract: A cholesterol-rich emulsion (LDE) that resembles the LDL lipidic structure is taken-up by LDL receptors after intravenous injection by means of apolipoprotein E it acquires in the circulation and can be used to probe LDL metabolism. In this study, LDE was labeled with 14Ccholesteryl oleate and 3Hcholesterol and injected into 19 patients with coronary artery disease (CAD) and into 14 subjects without CAD to verify whether the kinetic behavior of the radioactive lipids is different in CAD. Blood was sampled over 24 h for radioactivity measurement after lipid extraction and separation by thin-layer chromatography. Fractional clearance rate (FCR, in h-1) of 14Ccholesteryl ester was not different in CAD and nonCAD expressed as median (25%; 75%): 0.08 (0.062; 0.134) h-1 versus 0.06 (0.04; 0.083) h-1, P = 0.167. However, 3Hcholesterol FCR was greater in CAD than in nonCAD (mean +/- SEM): 0.163 +/- 0.016 h-1 versus 0.077 +/- 0.014 h-1, P < 0.001. Esterification of the LDE 3Hcholesterol was also greater in CAD subjects than nonCAD at 10 h and 24 h after emulsion injection (P = 0.029 and 0.024 respectively). In conclusion, both removal from the plasma and esterification of the LDE-cholesterol were increased in CAD. These findings may contribute for unraveling pro-atherogenic mechanisms and the establishment of novel CAD markers.

Plasma kinetics of a cholesterol-rich emulsion in young, middle-aged, and elderly subjects
Pinto, L. B., M. Wajngarten, et al. (2001), Lipids 36(12): 1307-11.
Abstract: Low density lipoprotein (LDL) plasma concentration is increased in the elderly. In this group, the incidence of coronary artery disease (CAD) is greater and LDL remains an important risk factor for CAD development. In this study, the plasma kinetics of a cholesterol-rich emulsion that binds to LDL receptors was studied in 10-subject groups of the elderly (70 +/- 4 yr), middle-aged (42 +/- 5 yr) and young (23 +/- 2 yr). All were normolipidemic, nonobese, nondiabetic subjects who did not have CAD. The emulsion was labeled with 14C-cholesteryl oleate and injected intravenously into the subjects. Blood samples were drawn at regular intervals over 24 h to determine the plasma decay curve of the emulsion radioactive label and to estimate its plasma fractional clearance rate (FCR, in h(-1)). FCR of the emulsion label was smaller in elderly compared to young subjects (0.032 +/- 0.035 and 0.071 +/- 0.049 h(-1), respectively; mean +/- SD, P< 0.05). FCR of the middle-aged subjects (0.050 +/- 0.071 h(-1)) was intermediate between the values of the elderly and young subjects, although not statistically different from them. A negative correlation was found betweeen the emulsion FCR and subjects' age (r = -0.47, P = 0.008). We conclude that aging is accompanied by progressively diminished clearance of the emulsion cholesterol esters and, by analogy, of the native LDL.

Plasma kinetics of a cholesterol-rich microemulsion in patients submitted to heart transplantation
Puk, C. G., C. G. Vinagre, et al. (2004), Transplantation 78(8): 1177-81.
Abstract: BACKGROUND: Development of coronary graft disease is currently the main cause of late heart-transplantation (HT) failure. HT patients frequently show hypercholesterolemia as well as alterations in chylomicron metabolism. These postHT changes may be important in coronary graft disease development. To clarify whether hypercholesterolemia is caused by decreased low-density lipoprotein (LDL) removal from the plasma, we studied the plasma kinetics of a cholesterol-rich emulsion that binds to LDL receptor. METHODS: We studied 13 HT patients and 13 healthy normolipidemic subjects paired for sex, age, and body mass index. An emulsion labeled with C-cholesteryl oleate was injected intravenously, and blood samples were collected in predetermined intervals (5 minutes, 1, 2, 4, 6, and 8 hours) to determine the radioactivity decay curves and to calculate the fractional clearance rates (FCR). RESULTS: The plasma level of total cholesterol, LDL cholesterol, high-density lipoprotein cholesterol, and apo B were greater in HT group than in the control group (P<0.005). FCR C-cholesteryl oleate was smaller in HT patients when compared with the control group (P=0.02). CONCLUSION: The results showed that HT patients have a deficiency in the mechanisms of LDL removal from the plasma, as tested by the cholesterol-rich emulsion, and this may be important in the development of coronary graft disease.

Plasma kinetics of a cholesterol-rich microemulsion in subjects with heterozygous beta-thalassemia
Naoum, F. A., S. F. Gualandro, et al. (2004), Am J Hematol 77(4): 340-5.
Abstract: Patients with beta-thalassemia trait have been reported to present lower plasma concentrations of low-density lipoprotein (LDL) and lower frequencies of acute myocardial infarction than normal subjects. In this study, the metabolism of LDL was tested in 12 patients with heterozygous beta-thalassemia trait (HBT) and 13 healthy subjects without the disease by determining the plasma kinetics of an artificially made cholesterol-rich microemulsion (LDE) that mimics the LDL metabolism and binds to LDL receptors. The emulsion was labeled with 14C-cholesterol ester and injected intravenously into the subjects. Blood samples were drawn at regular intervals over 24 hr to determine the plasma decay curve of the emulsion radioactive label and to estimate its plasma fractional clearance rate (FCR, in hr(-1)). FCR of the 14C-cholesterol ester was greater in HBT compared to controls (0.0631 +/- 0.0178 hr(-1) and 0.0501 +/- 0.0094 hr(-1), respectively; mean +/- SD, P = 0.022). No differences were found regarding LDL cholesterol plasma concentration between the two groups, but apolipoprotein B concentration was lower in HBT than in control subjects (80 +/- 44 and 96 +/- 14, respectively; mean +/- SD, P = 0.026). Our results show that LDE FCR is increased in HBT, indicating that LDL clearance is increased in patients with beta-thalassemia trait possibly due to the increased proliferation in the bone marrow of erythroid precursors.

Plasma kinetics of cholesteryl ester transfer protein in the rabbit. Effects of dietary cholesterol
McPherson, R., P. Lau, et al. (1997), Arterioscler Thromb Vasc Biol 17(1): 203-10.
Abstract: The plasma kinetics of recombinant human cholesteryl ester transfer protein (rCETP) were studied in six rabbits before and after cholesterol feeding (0.5% wt/wt). The rCETP, labeled with the use of the Bolton Hunter reagent, was shown to retain neutral lipid transfer activity. After intravenous infusion, labeled rCETP associated with rabbit lipoproteins to an extent similar to endogenous rabbit CETP (62% to 64% HDL associated). The plasma kinetics of CETP, modeled with the use of SAAM-II, conformed to a two-pool model, likely representing free and loosely HDL-associated CETP (fast pool) and a tightly apo (apolipoprotein) AI-associated (slow pool) CETP. The plasma residency time (chow diet) of the fast pool averaged 7.1 hours and of the slow pool, 76.3 hours. The production rate (PR) into and the fractional catabolic rate (FCR) of the fast pool were 20 and 10 times the PR and FCR, respectively, of the slow pool. In response to cholesterol feeding, CETP PR, FCR, and plasma mass increased by 416%, 60%, and 230%, respectively. There was a strong correlation (r =.95, P =.003) between the increase in rabbit plasma CETP and the modeled increase in CETP PR in response to cholesterol feeding, suggesting that labeled human rCETP is a satisfactory tracer for rabbit plasma CETP. CETP is catabolized by distinct pools, likely corresponding to an apo AI-associated (slow) pool and a free and/or loosely HDL-associated (fast) pool. Factors that alter the affinity of CETP for HDL would be predicted to result in altered CETP catabolism. The effect of dietary cholesterol on plasma CETP mass can be explained largely by the effects on CETP synthesis, consistent with the observed effects of cholesterol on tissue mRNA levels.

Plasma lecithin cholesterol acyl transferase activity, high density lipoprotein cholesterol and cholesterol ester in cholestasis
Agbedana, E. O., G. O. Taylor, et al. (1993), Afr J Med Med Sci 22(3): 41-4.
Abstract: Lecithin cholesterol acyl transferase activity, cholesterol ester and high density lipoprotein cholesterol concentrations were determined in Nigerian subjects suffering from cholestatic jaundice. Plasma lecithin cholesterol acyl transferase activities in all the study groups were similar. High density lipoprotein cholesterol and cholesterol ester were significantly increased in extrahepatic cholestasis while reduced levels were found in intrahepatic cholestasis. Enhanced cholesterol esterification may occur in extrahepatic cholestasis.

Plasma lecithin: cholesterol acyltransferase and plasma lipolytic activity in preterm infants given total parenteral nutrition with 10% or 20% Intralipid
Goel, R., M. Hamosh, et al. (1995), Acta Paediatr 84(9): 1060-4.
Abstract: The effect of 10% or 20% Intralipid on lipid clearing enzymes, plasma lipids and apoproteins was investigated during the first 5 days after birth in 37 premature infants maintained on total parenteral nutrition; 21 infants received 20% and 16 received 10% Intralipid, respectively. Lipid was infused over a 20-h period at rates of 1, 2 and 3 g/kg/day on consecutive days. Plasma lecithin: cholesterol acyltransferase (LCAT) activity was low and increased significantly (p<0.05) only during infusions of 3 g/kg/day in both groups of infants. Plasma lipolytic activity was generally not affected by the regimen or preparation (10% or 20%) of Intralipid infused, except for higher (p<0.05) levels at 3 g/kg/day of 20% compared with prelipid infusion. Plasma triglyceride concentrations wer similar after 10% or 20% Intralipid, whereas plasma total cholesterol was significantly higher during infusion of 2 and 3 g/kg/day of 10% compared with 20% Intralipid. The efficient clearing of 20% Intralipid might be related to the lower lecithin: triglyceride ration which is compatible with the low LCAT activity of premature infants.

Plasma lecithin-cholesterol acyltransferase activity and cholesterol and phospholipid levels in premature newborn infants
Jain, S. K. and J. J. Diaz (1991), Biochim Biophys Acta 1086(2): 225-9.
Abstract: Lecithin-cholesterol acyltransferase (LCAT) activity has been suggested to play an important role in the regulation of lipid metabolism. The present study was undertaken to examine any relationship between LCAT activity and altered cholesterol levels in plasma of full-term and preterm newborn infants. Plasma total, free and esterified cholesterol, total phospholipid and LCAT activity (cholesterol esterified, nmol/ml per h) were determined in placental cord blood. There was a significant negative relationship between total cholesterol levels and gestational age. The increased cholesterol with prematurity was due to both free and esterified cholesterol. There was also a significant negative relationship between LCAT activity and free cholesterol levels but not between LCAT activity and total cholesterol and esterified cholesterol levels. There was no relationship between esterified-to-free cholesterol ratio and LCAT activity. Total phospholipid was not significantly related to either gestational age or LCAT activity. This study suggests that reduced LCAT activity may be one of the factors that result in the accumulation of cholesterol in premature infants.

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