Plasma Lecithin:cholesterol Acyltransferase Activity Research Articles

Seasonal Factors Are Associated with Activities of Enzymes Involved in High-Density Lipoprotein Metabolism among Pregnant Females in Ghana

BackgroundSmall-quantity lipid-based nutrient supplements (SQ-LNS) during pregnancy and postnatally were previously shown to improve high-density lipoprotein (HDL) cholesterol efflux capacity (CEC) and length in the children of supplemented mothers at 18 mo of age in the International Lipid-Based Nutrient Supplements (iLiNS) DYAD trial in Ghana. However, the effects of SQ-LNS on maternal HDL functionality during pregnancy are unknown. ObjectiveThe goal of this cross-sectional, secondary outcome analysis was to compare HDL function in mothers supplemented with SQ-LNS vs. iron and folic acid (IFA) during gestation. MethodsHDL CEC and the activities of 3 HDL-associated enzymes were analyzed in archived plasma samples (N = 197) from a subsample of females at 36 weeks of gestation enrolled in the iLiNS-DYAD trial in Ghana. Correlations between HDL function and birth outcomes, inflammatory markers C-reactive protein (CRP) and alpha-1-acid glycoprotein (AGP), and the effects of season were explored to determine the influence of these factors on HDL function in this cohort of pregnant females. ResultsThere were no statistically significant differences in HDL CEC, plasma lecithin-cholesterol acyltransferase (LCAT) activity, cholesteryl ester transfer protein (CETP) activity, or phospholipid transfer protein (PLTP) activity between mothers supplemented with SQ-LNS compared with IFA control, and no statistically significant relationships between maternal HDL function and childbirth outcomes. LCAT activity was negatively correlated with plasma AGP (R = -0.19, P = 0.007) and CRP (R = -0.28, P < 0.001), CETP and LCAT activity were higher during the dry season compared to the wet season, and PLTP activity was higher in the wet season compared to the dry season. ConclusionsMothers in Ghana supplemented with SQ-LNS compared with IFA during gestation did not have measurable differences in HDL functionality, and maternal HDL function was not associated with childbirth outcomes. However, seasonal factors and markers of inflammation were associated with HDL function, indicating that these factors had a stronger influence on HDL functionality than SQ-LNS supplementation during pregnancy. Clinical Trial Registry numberThe study was registered as NCT00970866. https://clinicaltrials.gov/study/NCT00970866

Influence of lecithin cholesterol acyltransferase alteration during different pathophysiologic conditions: A 45years bibliometrics analysis.

Background: Lecithin cholesterol acyltransferase (LCAT) is an important enzyme responsible for free cholesterol (FC) esterification, which is critical for high density lipoprotein (HDL) maturation and the completion of the reverse cholesterol transport (RCT) process. Plasma LCAT activity and concentration showed various patterns under different physiological and pathological conditions. Research on LCAT has grown rapidly over the past 50 years, but there are no bibliometric studies summarizing this field as a whole. This study aimed to use the bibliometric analysis to demonstrate the trends in LCAT publications, thus offering a brief perspective with regard to future developments in this field. Methods: We used the Web of Science Core Collection to retrieve LCAT-related studies published from 1975 to 2020. The data were further analyzed in the number of studies, the journal which published the most LCAT-related studies, co-authorship network, co-country network, co-institute network, co-reference and the keywords burst by CiteSpace V 5.7. Results: 2584 publications contained 55,311 references were used to analyzed. The number of included articles fluctuated in each year. We found that Journal of lipid research published the most LCAT-related studies. Among all the authors who work on LCAT, they tend to collaborate with a relatively stable group of collaborators to generate several major authors clusters which Albers, J. published the most studies (n = 53). The United States of America contributed the greatest proportion (n = 1036) of LCAT-related studies. The LCAT-related studies have been focused on the vascular disease, lecithin-cholesterol acyltransferase reaction, phospholipid, cholesterol efflux, chronic kidney disease, milk fever, nephrotic syndrome, platelet-activating factor acetylhydrolase, reconstituted lpa-i, reverse cholesterol transport. Four main research frontiers in terms of burst strength for LCAT-related studies including "transgenic mice", "oxidative stress", "risk", and "cholesterol metabolism "need more attention. Conclusion: This is the first study that demonstrated the trends and future development in LCAT publications. Further studies should focus on the accurate metabolic process of LCAT dependent or independent of RCT using metabolic marker tracking techniques. It was also well worth to further studying the possibility that LCAT may qualify as a biomarker for risk prediction and clinical treatment.

Plasma Lecithin-Cholesterol Acyltransferase Activity in Pregnant Women Enrolled in the iLiNS-DYAD Trial in Ghana

ObjectivesThe International Lipid-Based Nutrient Supplement (iLiNS) Project developed small-quantity lipid-based nutrient supplements (SQ-LNS) for mothers and their children with the goal of reducing malnutrition. The aim of this secondary outcome analysis is to investigate the effects of SQ-LNS on the activity of plasma lecithin-cholesterol acyltransferase (LCAT), a key enzyme involved in the remodeling of high-density lipoprotein (HDL) particles, which increases their cholesterol carrying capacity.MethodsPlasma samples from a subset of 197 out of 1320 women at 36-wk gestation enrolled in the iLiNS-DYAD trial in Ghana were analyzed. In the main cohort, women were enrolled during the second trimester (≤ 20 wk gestation) and randomly assigned to receive SQ-LNS, iron and folic acid (IFA), or a multiple micronutrient supplement. Women in this subset received either SQ-LNS or IFA. Plasma LCAT activity was measured using a commercial fluorometric kit and the non-transformed data was compared by Wilcoxon test (mean ± SD). LCAT activity is expressed as a ratio (390 nm/470 nm), where greater ratio indicates higher enzyme activity. We also explored whether LCAT activity differed by enrollment season (Dry, November–April; Wet, May-October) or was associated with biomarkers of inflammation.ResultsThere was no significant difference in LCAT activity between the SQ-LNS and IFA groups (1.44 ± 0.17 vs. 1.41 ± 0.14, P = 0.24). Women enrolled during the wet season had higher LCAT activity than women enrolled during the dry season (1.47 ± 0.15 vs. 1.37 ± 0.14, P < 0.001), with no differences between intervention groups stratified by season (P > 0.05). LCAT activity was negatively correlated with inflammatory biomarkers α1-acid glycoprotein (R = −0.19, P = 0.007) and C-reactive protein (R = −0.28, P < 0.001) measured at 36-wk gestation.ConclusionsPlasma LCAT activity, as a measure of HDL maturation and cholesterol carrying capacity, is more sensitive to factors mediated by seasonal variation (e.g., infection, inflammation) than by nutrient supplementation in this cohort of women in Ghana. These findings confirm a previously established link between HDL and inflammation.Funding SourcesThis project was supported by Bill & Melinda Gates Foundation grant (OPP124589) to the University of California, Davis.

ApoE and apoC-III-defined HDL subtypes: a descriptive study of their lecithin cholesterol acyl transferase and cholesteryl ester transfer protein content and activity

BackgroundThe functionality of high-density lipoproteins (HDL) is a better cardiovascular risk predictor than HDL concentrations. One of the key elements of HDL functionality is its apolipoprotein composition. Lecithin-cholesterol acyl transferase (LCAT) and cholesterol-ester transfer protein (CETP) are enzymes involved in HDL-mediated reverse cholesterol transport. This study assessed the concentration and activity of LCAT and CETP in HDL subspecies defined by their content of apolipoproteins E (apoE) and C-III (apoC-III) in humans.MethodsEighteen adults (ten women and eight men, mean age 55.6, BMI 26.9 Kg/m2, HbA1c 5.4%) were studied. HDL from each participant were isolated and divided into four subspecies containing respectively: No apoE and no apoC-III (E-C-), apoE but not apoC-III (E + C-), apoC-III but no apoE (E-C+) and both apoE and apoC-III (E + C+). The concentration and enzymatic activity of LCAT and CETP were measured within each HDL subspecies using immunoenzymatic and fluorometric methods. Additionally, the size distribution of HDL in each apolipoprotein-defined fraction was determined using non-denaturing electrophoresis and anti-apoA-I western blotting.ResultsHDL without apoE or apoC-III was the predominant HDL subtype. The size distribution of HDL was very similar in all the four apolipoprotein-defined subtypes. LCAT was most abundant in E-C- HDL (3.58 mg/mL, 59.6% of plasma LCAT mass), while HDL with apoE or apoC-III had much less LCAT (19.8, 12.2 and 8.37% of plasma LCAT respectively for E + C-, E-C+ and E + C+). LCAT mass was lower in E + C- HDL relative to E-C- HDL, but LCAT activity was similar in both fractions, signaling a greater activity-to-mass ratio associated with the presence of apoE. Both CETP mass and CETP activity showed only slight variations across HDL subspecies. There was an inverse correlation between plasma LCAT activity and concentrations of both E-C+ pre-beta HDL (r = − 0.55, P = 0.017) and E-C- alpha 1 HDL (r = − 0.49, P = 0.041). Conversely, there was a direct correlation between plasma CETP activity and concentrations of E-C+ alpha 1 HDL (r = 0.52, P = 0.025).ConclusionsThe presence of apoE in small HDL is correlated with increased LCAT activity and esterification of plasma cholesterol. These results favor an interpretation that LCAT and apoE interact to enhance anti-atherogenic pathways of HDL.

Recombinant LCAT (Lecithin:Cholesterol Acyltransferase) Rescues Defective HDL (High-Density Lipoprotein)-Mediated Endothelial Protection in Acute Coronary Syndrome.

Objective- Aim of this study was to evaluate changes in LCAT (lecithin:cholesterol acyltransferase) concentration and activity in patients with an acute coronary syndrome, to investigate if these changes are related to the compromised capacity of HDL (high-density lipoprotein) to promote endothelial nitric oxide (NO) production, and to assess if rhLCAT (recombinant human LCAT) can rescue the defective vasoprotective HDL function. Approach and Results- Thirty ST-segment-elevation myocardial infarction (STEMI) patients were enrolled, and plasma was collected at hospital admission, 48 and 72 hours thereafter, at hospital discharge, and at 30-day follow-up. Plasma LCAT concentration and activity were measured and related to the capacity of HDL to promote NO production in cultured endothelial cells. In vitro studies were performed in which STEMI patients' plasma was added with rhLCAT and HDL vasoprotective activity assessed by measuring NO production in endothelial cells. The plasma concentration of the LCAT enzyme significantly decreases during STEMI with a parallel significant reduction in LCAT activity. HDL isolated from STEMI patients progressively lose the capacity to promote NO production by endothelial cells, and the reduction is related to decreased LCAT concentration. In vitro incubation of STEMI patients' plasma with rhLCAT restores HDL ability to promote endothelial NO production, possibly related to significant modification in HDL phospholipid classes. Conclusions- Impairment of cholesterol esterification may be a major factor in the HDL dysfunction observed during acute coronary syndrome. rhLCAT is able to restore HDL-mediated NO production in vitro, suggesting LCAT as potential therapeutic target for restoring HDL functionality in acute coronary syndrome.

Cholesteryl ester transfer protein (CETP), HDL capacity of receiving cholesterol and status of inflammatory cytokines in patients with severe heart failure

BackgroundHeart failure (HF) courses with chronic inflammatory process and alterations in lipid metabolism may aggravate the disease. The aim was to test whether the severity of HF, using brain natriuretic peptide (BNP) as a marker, is associated with alterations in functional aspects of HDL, such as lipid transfer, cholesterol ester transfer protein (CETP) and lecithin-cholesterol acyltransferase (LCAT) concentration.MethodsTwenty-five HF patients in NYHA class I/II and 23 in class III/IV were enrolled. Plasma lipids, apolipoproteins, CETP, LCAT, oxidized-LDL (oxLDL) and paraoxonase-1 (PON-1) activity were determined. Lipid transfer from a donor artificial nanoparticle to HDL was measured by in vitro assay.ResultsTotal cholesterol (p = 0.049), LDL-C (p = 0.023), non-HDL-C (p = 0.029) and CETP, that promotes lipid transfer among lipoproteins (p = 0.013), were lower in III/IV than in I/II group. Triglycerides, HDL-C, apo A-I, apo B, oxLDL, LCAT, enzyme that catalyzes serum cholesterol esterification, PON-1 activity, and in vitro transfers of cholesterol, triglycerides and phospholipids to HDL, important steps in HDL metabolism, were equal. IL-8 was higher in III/IV (p = 0.025), but TNFα, IL-1β, IL-6 and MCP-1 were equal. BNP was negatively correlated with CETP (r = − 0.294; p = 0.042) and positively correlated with IL-8 (r = 0.299; p = 0.039).ConclusionsOur results disclosed the relationship between CETP levels and HF severity, by comparing two HF groups and by correlation analysis. Lower CETP levels may be a marker of HF aggravation and possibly of worse prognosis. Practical applications of this initial finding, as the issue whether CETP could be protective against HF aggravation, should be explored in larger experimental and clinical studies.

Plasma lecithin:cholesterol acyltransferase and phospholipid transfer protein activity independently associate with nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is a highly prevalent condition which contributes to atherogenic apolipoprotein B dyslipoproteinemias. Lecithin:cholesterol acyltransferase (LCAT) and phospholipid transfer protein (PLTP) are both synthesized by the liver and are important in lipid metabolism. Here, we interrogated the impact of NAFLD on plasma LCAT and PLTP activities. Plasma LCAT activity (exogenous substrate assay) and PLTP activity (phospholipid vesicles-HDL assay) were determined in 348 subjects (279 men; 81 subjects with type 2 diabetes (T2DM); 123 with metabolic syndrome (MetS)). A Fatty Liver Index (FLI) ≥60 was used as a proxy of NAFLD. Insulin resistance was determined by homoeostasis model assessment (HOMA-IR). A total of 147 participants had an FLI ≥60 coinciding with T2DM and MetS (P<0.001 for each). Plasma LCAT activity and PLTP activity were on average 12% and 5% higher, respectively, in subjects with an FLI≥60 (P<0.001 for each). In age- and sex-adjusted partial linear regression analysis, LCAT activity and PLTP activity were positively related to various obesity measures and HOMA-IR (P<0.001 for each). In multivariable linear regression analyses adjusted for age and sex, LCAT activity was associated with an FLI≥60 independent of T2DM and MetS, the waist/hip ratio, or HOMA-IR (β=0.307 to 0.366, P<0001 for all models). PLTP activity was also associated with an FLI≥60 independent of these variables (β=0.151 to 0223, P=0.013 to 0.001). NAFLD, as inferred from an FLI≥60, confers higher plasma LCAT and to a lesser extent PLTP activity, even when taking account of T2DM, MetS, central obesity and insulin resistance.

Abstract 226: Mechanism of LCAT Activation by Compound A

Background: Lecithin:cholesterol acyltransferase (LCAT) catalyzes cholesteryl ester (CE) production from free cholesterol (FC) and phosphatidylcholine (lecithin), promoting HDL formation. Objective: To investigate activation of LCAT by Compound A (Amgen), a previously described small-molecule activator of LCAT, with the ultimate goal of developing novel LCAT activators for therapeutic use. Methods: LCAT activity in plasma from Familial LCAT Deficiency (FLD) patients with different mutations was quantitated by TLC before and after addition of Compound A. HEK293 cells were transiently transfected with plasmids containing wild-type (WT) or mutant LCAT cDNA. Media was then incubated with either vehicle or Compound A and LCAT activity was quantitated using a novel plate assay utilizing Methylumbelliferyl Palmitate as a substrate. Results: Compound A increased LCAT activity for a subset of FLD mutations to a level above which renal disease may occur. Mutations of Cys31 in vitro strongly affected basal LCAT activity as well as activation by Compound A. Charged residues at position 31 profoundly decreased activity whereas bulky hydrophobic groups increased LCAT activity up to 3-fold (p &lt; 0.005, all). Mass spectrometry of WT LCAT incubated with Compound A revealed a +103.017 m/z adduct to the tryptic peptide containing Cys31, indicative of a cyanopyrazine adduct to LCAT Cys31. Molecular modeling identified potential binding sites of Compound A to LCAT. Conclusions: Our findings yield important mechanistic insight into LCAT activation that can be used to design novel LCAT activators for therapeutic use.

9. AAV-Mediated Gene Transfer as a Therapeutic Approach for Familial LCAT Deficiency

Lecithin Cholesterol Acyltransferase (LCAT) is a plasma enzyme secreted by the liver and responsible for esterification of free cholesterol to cholesteryl ester in the blood compartment. Familial LCAT deficiency (FLD) is an autosomal recessive disorder caused by loss-of-function mutations of the LCAT gene and is characterized by extremely low levels of high density lipoprotein cholesterol (HDL-C), anemia, corneal opacities, and chronic progressive renal disease leading to end-stage kidney disease as early as the third decade of life. Currently, there is no specific treatment for FLD. The fact that patients with even very low levels of plasma LCAT activity do not develop kidney disease make FLD an attractive candidate for liver-directed gene therapy with adeno-associated viral (AAV) vectors. LCAT is activated by apolipoprotein A-I (apoA-I) and this interaction is highly species specific. Therefore, LCAT KO mice were crossed with human apoA-I transgenic (hApoAITg) mice in order to facilitate experiments involving expression of human LCAT. LCAT KO/hApoAI transgenic mice received a single IP injection of AAV8 encoding human LCAT in a dose range of 5e10 GC/kg to 5e11 GC/kg. HDL-C increased in a dose-dependent fashion, from 32 mg/dL in the control group to 103 mg/dL at the dose of 1.5e11 GC/kg and 473 mg/dL at the dose of 5e11 GC/kg. Plasma% cholesterol ester, a sensitive indicator of LCAT activity, was normalized at the low dose of 1.5e11 GC/kg. Thus, we demonstrate that low doses of AAV8-hLCAT provide stable expression of the LCAT enzyme and correct dyslipidemia in a ‘humanized’ mouse model of LCAT deficiency. Studies designed to demonstrate prevention of kidney disease in this mouse model are ongoing. These proof-of-concept studies provide a foundation for further development of AAV-based gene therapy for familial LCAT deficiency.

Case report: A novel apolipoprotein A-I missense mutation apoA-I (Arg149Ser)Boston associated with decreased lecithin-cholesterol acyltransferase activation and cellular cholesterol efflux

We report a novel heterozygous apolipoprotein A-I (apoA-I) missense mutation (c.517C>A, p.Arg149Ser, designated as apoA-IBoston) in a 67-year-old woman and her 2 sons, who had mean serum high-density lipoprotein (HDL) cholesterol, apoA-I, and apoA-I in very large α-1 HDL that were 10%, 35%, and 16% of normal, respectively (all P < .05). The percentage of HDL cholesterol in the esterified form was also significantly (P < .05) reduced to 52% of control values. Cholesteryl ester tranfer protein (CETP) activity was normal. The mean global, adenosine triphosphate (ATP)-binding cassette transporter A1 and scavenger receptor B type I–mediated cellular cholesterol efflux capacity in apoB-depleted serum from affected family members were 41%, 37%, 47%, 54%, and 48% of control values, respectively (all P < .05). lecithin-cholesterol acyltransferase (LCAT) activity in plasma was 71% of controls, whereas in the cell-based assay, it was 73% of control values (P < .05). The data indicate that this novel apoA-I missense is associated with markedly decreased levels of HDL cholesterol and very large α-1 HDL, as well as decreased serum cellular cholesterol efflux and LCAT activity, but not with premature coronary heart disease, similar to other apoA-I mutations that have been associated with decreased LCAT activity.

Rice protein regulates HDL metabolism-related gene expression and enzyme activity in adult rats

To elucidate whether rice protein possess a vital function in regulating high density lipoprotein (HDL) metabolism, the effects of rice protein (RP) on HDL metabolism-related gene expressions and enzyme activities were investigated in adult rats. Compared with casein, lipid contents in plasma and liver were effectively reduced by RP-feeding, accompanying significant increased ratio of HDL to cholesterol or triglyceride. RP increased mRNA levels of lecithin-cholesterol acyltransferase, adenosine triphosphate-binding cassette transporter A1, scavenger receptor class B type I and liver X receptor α, as compared to casein. Hepatic activities of lipoprotein lipase and hepatic lipase were significantly stimulated by RP, whereas no significant difference of plasma lecithin-cholesterol acyltransferase activity was found in RP with respect to casein. Results demonstrated that rice protein could effectively regulate HDL metabolism through modifying the HDL metabolism-related gene expression levels and lipolytic enzyme activities, which involved with a hypocholesterolemic action during the adult period.

Lipid Lowering potential of Andrographis paniculata (Nees)

Aim: Atherosclerosis and associated complications is now the major cause of myocardial morbidity and mortality worldwide. Therefore we have selected the Andrographis paniculata for the development of lipid lowering drug. Material and Methods: The lipid lowering activity of mixture of andrographaloides isolated from the leaves of the Andrographis paniculata has been studied in Triton and cholesterol fed hyperlipidemic rats (in vivo). Results: Serum lipids were found to be lowered by andrographaloides (at 50 mg/kg.) in Triton WR-1339 induced hyperlipidemia in experimental animals. Chronic feeding of this mixture of andrographolides (at 25 mg/kg) in animals, simultaneously fed with high fat diet (HFD) for 30 days caused lowering in the lipid and apoprotein levels of very low density (VLDL) and low density lipoproteins (LDL) It has also increased high density lipoprotein (HDL). Andrographaloides activated lipolytic enzymes in plasma and liver lipids. The hypolipidemic activity of the andrographaloides mixture is mediated through increased faecal bile acid excretion and enhanced plasma lecithin-cholesterol acyl transferase activity. Conclusion: Mixture of Andrographolides was found to lower the lipids in experimental animals.

Alterations in plasma lecithin:cholesterol acyltransferase and myeloperoxidase in acute myocardial infarction: Implications for cardiac outcome

BackgroundThe cholesterol esterifying enzyme, lecithin:cholesterol acyltransferase (LCAT), plays a key role in HDL maturation and remodeling. Myeloperoxidase (MPO) may compromise LCAT enzymatic activity. We tested the extent to which plasma LCAT activity is altered in acute myocardial infarction (MI) in conjunction with abnormal MPO levels. We also assessed the impact of LCAT and MPO on newly developed major adverse cardiovascular events (MACE). MethodsTwo-hundred one consecutive patients referred for acute chest pain of whom 134 had MI (95 with ST-elevation) participated. Forty-five new MACE were ascertained during 1203 (range 13–1745) days of follow-up among 185 patients. Plasma LCAT activity was measured using an exogenous substrate assay. MPO mass was assayed by chemiluminescent microparticle immunoassay. ResultsPlasma LCAT activity was decreased by 15%, coinciding with 7-fold increased MPO levels in acute MI patients vs. patients with non-cardiac chest pain (p < 0.001 for both; correlation: r = −0.343, p < 0.001). MI at admission was associated independently with both lower plasma LCAT activity and higher MPO (age- and sex-adjusted odds ratio per 1 SD increment: 0.46 (95% CI, 0.31–0.68), p < 0.001 and 7.58 (95% CI, 3.34–17.11), p < 0.001, respectively). In an analysis with LCAT and MPO together these associations were modestly attenuated. MPO mass (hazard ratio: 1.59 (95% CI, 1.15–2.19), p = 0.004), but not LCAT activity (hazard ratio: 0.87 (95% CI, 0.65–1.19), p = 0.39), predicted newly manifest MACE. ConclusionIn acute MI patients, plasma LCAT activity is decreased coinciding with increased MPO levels. Higher MPO but not lower LCAT activity prospectively predicts adverse cardiac outcome.

Lipid-lowering effect of molluscan (Katelysia opima) glycosaminoglycan (GAG) in hypercholesterolemic induced rats

Identifying pharmacologically safe lipid-lowering 'deliverables' could potentiate therapeutic outcome for diet-induced atherogenesis. Accordingly, we investigated the potential of molluscan (Katelysia opima) glycosaminoglycan (GAG) in modulating the early lipid changes in atherogenesis. Wistar rats were fed a diet with (n=24) or without (n=6) hypercholesterolemic atherogenic CCT (rat chow supplemented with 4% cholesterol, 1% cholic acid, and 0.5% thiouracil) for 17 days. CCT-fed rates were (i) treated with isolated molluscan GAG (40 mg/kg/day, s.c.) for 10 days after the introduction of CCT diet, (ii) cotreated with GAG (40 mg/kg/day, s.c.) for 17 days, or (iii) treated with heparin (200 units/kg/day, s.c.) for 10 days after the introduction of CCT. The increases induced by CCT diet in the plasma levels of cholesterol, triglycerides, high-density lipoprotein, very-low-density lipoprotein, and low-density lipoprotein were completely attenuated with GAG treatment. Consistently, alterations induced by CCT diet in the levels of plasma lecithin cholesterol acyltransferase and lipoprotein lipase activities were restored to baseline levels with GAG treatment. Coherently, histology revealed a decrease associated with GAG treatment in the CCT-diet-induced foam cells (in aorta), tubular damages (kidney), and lipid accumulations (liver). Together, these results suggest that GAG may exert antiatherogenesis potential by significantly attenuating lipid modulations derived by a high-fat diet. Further, the data imply that the GAG extracts may comprehensively prevent hypercholesterolemia-associated tissue damage and could thus serve as a therapeutic deliverable for hypercholesterolemia.

Hybrid benzofuran–bisindole derivatives: New prototypes with promising anti-hyperlipidemic activities

A series of different benzofuran–bisindole hybrids were synthesized and evaluated in vitro for their antioxidant and in vivo for antidyslipidemic activity in triton WR-1339 induced hyperlipidemic rats. Among the series, compounds 4a, 4c, 4h and 4j showed significant decrease in plasma levels of total cholesterol (TC), phospholipids (PL) and triglycerides (TG) followed by increase in post heparin lipolytic activity (PHLA). In addition, the active hybrids possessed moderate antioxidant properties and increased the plasma lecithin cholesterol acyltransferase (LCAT) activity, which plays a key role in lipoprotein metabolism contributing to an increased level of HDL-C in serum. These results indicate that these hybrids constitute novel prototypes for the management of dyslipidemia.

A fluorescence method to detect and quantitate sterol esterification by lecithin:cholesterol acyltransferase

We describe a simple but sensitive fluorescence method to accurately detect the esterification activity of lecithin:cholesterol acyltransferase (LCAT). The new assay protocol employs a convenient mix, incubate, and measure scheme. This is possible by using the fluorescent sterol dehydroergosterol (DHE) in place of cholesterol as the LCAT substrate. The assay method is further enhanced by incorporation of an amphiphilic peptide in place of apolipoprotein A-I as the lipid emulsifier and LCAT activator. Specific fluorescence detection of DHE ester synthesis is achieved by employing cholesterol oxidase to selectively render unesterified DHE nonfluorescent. The assay accurately detects LCAT activity in buffer and in plasma that is depleted of apolipoprotein B lipoproteins by selective precipitation. Analysis of LCAT activity in plasmas from control subjects and sickle cell disease (SCD) patients confirms previous reports of reduced LCAT activity in SCD and demonstrates a strong correlation between plasma LCAT activity and LCAT content. The fluorescent assay combines the sensitivity of radiochemical assays with the simplicity of nonradiochemical assays to obtain accurate and robust measurement of LCAT esterification activity.

Skew of Plasma Low- and High-Density Lipoprotein Distributions to Less Dense Subfractions in Normotriglyceridemic Chronic Kidney Disease Patients on Maintenance Hemodialysis Treatment

Background: Plasma levels of small, dense low-density lipoprotein (LDL) were reported to increase in chronic kidney disease (CKD) patients on hemodialysis (HD), but most of these patients were hypertriglyceridemic. Plasma levels of small, dense LDL are known to increase in hypertriglyceridemic subjects. Therefore, to investigate the direct effect of CKD on the distribution of LDL subfractions, we investigated the distribution of LDL subfractions in normotriglyceridemic CKD patients on HD. Methods: The levels of plasma lipoprotein subfractions and lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP), which markedly influence the distributions of plasma LDL and high-density lipoprotein (HDL) subfractions, were compared between 40 HD patients and 40 normolipidemic controls. Plasma lipoproteins were subfractionated into seven subfractions by ultracentrifugation. Results: Plasma levels of cholesterol (C) in remnant-like particle, which is equivalent to the triglyceride (TG)-rich lipoprotein remnant, were twice as high in HD patients as those in controls with matched TG levels. Plasma levels of C and TG in VLDL and IDL (intermediate density lipoprotein) were slightly higher in HD patients than in controls. The C/TG ratio of VLDL was significantly higher in HD patients than in controls. In comparison with the corresponding values in controls, the C and TG levels in low-density LDL and HDL₂ in HD patients were high, whereas those in medium-density LDL, high-density LDL, and HDL₃ were low. Plasma LCAT activity and CETP mass were lower in HD patients than in controls. Conclusion: Distribution of LDL and HDL skewed toward less dense fractions in normotriglyceridemic CKD patients on HD. A decrease in reverse C transport likely played an important role in these changes in the patients.

Lipid Oxidation in Carriers of Lecithin:Cholesterol Acyltransferase Gene Mutations

Lecithin:cholesterol acyltransferase (LCAT) has been shown to play a role in the depletion of lipid oxidation products, but this has so far not been studied in humans. In this study, we investigated processes and parameters relevant to lipid oxidation in carriers of functional LCAT mutations. In 4 carriers of 2 mutant LCAT alleles, 63 heterozygotes, and 63 family controls, we measured activities of LCAT, paraoxonase 1, and platelet-activating factor-acetylhydrolase; levels of lysophosphatidylcholine molecular species, arachidonic and linoleic acids, and their oxidized derivatives; immunodetectable oxidized phospholipids on apolipoprotein (apo) B-containing and apo(a)-containing lipoproteins; IgM and IgG autoantibodies to malondialdehyde-low-density lipoprotein and IgG and IgM apoB-immune complexes; and the antioxidant capacity of high-density lipoprotein (HDL). In individuals with LCAT mutations, plasma LCAT activity, HDL cholesterol, apoA-I, arachidonic acid, and its oxidized derivatives, oxidized phospholipids on apo(a)-containing lipoproteins, HDL-associated platelet-activating factor-acetylhydrolase activity, and the antioxidative capacity of HDL were gene-dose-dependently decreased. Oxidized phospholipids on apoB-containing lipoproteins was increased in heterozygotes (17%; P<0.001) but not in carriers of 2 defective LCAT alleles. Carriers of LCAT mutations present with significant reductions in LCAT activity, HDL cholesterol, apoA-I, platelet-activating factor-acetylhydrolase activity, and antioxidative potential of HDL, but this is not associated with parameters of increased lipid peroxidation; we did not observe significant changes in the oxidation products of arachidonic acid and linoleic acid, immunoreactive oxidized phospholipids on apo(a)-containing lipoproteins, and IgM and IgG autoantibodies against malondialdehyde-low-density lipoprotein. These data indicate that plasma LCAT activity, HDL-associated platelet-activating factor-acetylhydrolase activity, and HDL cholesterol may not influence the levels of plasma lipid oxidation products.

The thienotriazolodiazepine Ro 11-1464 increases plasma apoA-I and promotes reverse cholesterol transport in human apoA-I transgenic mice

Ro 11-1464 is a thienotriazolodiazepine previously described to selectively stimulate apolipoprotein A-I (apoA-I) production and mRNA level in human liver cells. Here, we studied its effects upon oral administration to human apoA-I transgenic (hapoA-I) mice. HapoA-I mice were treated for 5 days with increasing doses of Ro 11-1464. Macrophage reverse cholesterol transport (mph-RCT) was assessed by following [(3) H]-cholesterol mobilization from pre-labelled i.p. injected J774 macrophages to plasma, liver and faeces. Effects on plasma lipids, apoproteins, lecithin-cholesterol : acyltransferase (LCAT) and liver enzymes, as well as on faecal excretion of cholesterol and bile salts, and on liver lipids and mRNA contents were determined. Treatment with Ro 11-1464 300 mg·kg(-1) ·day(-1) resulted in a nearly 2-fold increase in plasma apoA-I, a 2- to 3-fold increase in the level of large sized-pre-β high-density lipoprotein and a 3-fold selective up-regulation of hepatic apoA-I mRNA, but a marked decrease in all plasma lipids and LCAT activity. Mpm-RCT was decreased in blood but markedly increased in faecal sterols (4-fold) and bile acids (1.7-fold). However, liver weight and liver enzymes in plasma were also increased, in parallel with an increase in liver cholesterol ester content (all these effect being significant). In this model Ro 11-1464 causes increased hepatic expression and plasma levels of apoA-I and a suppression of LCAT, and a marked enhancement of reverse cholesterol transport, but also some symptoms of liver toxicity. The compound may therefore be a prototype for a next generation of anti-atherosclerotic medicines.

Small molecule activation of lecithin cholesterol acyltransferase modulates lipoprotein metabolism in mice and hamsters

The objective was to assess whether pharmacological activation of lecithin cholesterol acyltransferase (LCAT) could exert beneficial effects on lipoprotein metabolism. A putative small molecule activator (compound A) was used as a tool compound in in vitro and in vivo studies. Compound A increased LCAT activity in vitro in plasma from mouse, hamster, rhesus monkey, and human. To assess the acute pharmacodynamic effects of compound A, C57Bl/6 mice and hamsters received a single dose (20 mg/kg) of compound A. Both species displayed a significant increase in high-density lipoprotein cholesterol (HDLc) and a significant decrease in non-HDLc and triglycerides acutely after dosing; these changes tracked with ex vivo plasma LCAT activity. To examine compound A's chronic effect on lipoprotein metabolism, hamsters received a daily dosing of vehicle or of 20 or 60 mg/kg of compound A for 2 weeks. At study termination, compound treatment resulted in a significant increase in HDLc, HDL particle size, plasma apolipoprotein A-I level, and plasma cholesteryl ester (CE) to free cholesterol ratio, and a significant reduction in very low-density lipoprotein cholesterol. The increase in plasma CE mirrored the increase in HDL CE. Triglycerides trended toward a dose-dependent decrease in very low-density lipoprotein and HDL, with multiple triglyceride species reaching statistical significance. Gallbladder bile acids content displayed a significant and more than 2-fold increase with the 60 mg/kg treatment. We characterized pharmacological activation of LCAT by a small molecule extensively for the first time, and our findings support the potential of this approach in treating dyslipidemia and atherosclerosis; our analyses also provide mechanistic insight on LCAT's role in lipoprotein metabolism.