Impaired HDL antioxidant and anti-inflammatory functions are linked to increased mortality in acute heart failure patients.

AIMS: Acute heart failure (AHF) is typified by inflammatory and oxidative stress responses, which are associated with unfavorable patient outcomes. Given the anti-inflammatory and antioxidant properties of high-density lipoprotein (HDL), this study sought to examine the relationship between impaired HDL function and mortality in AHF patients. The complex interplay between various HDL-related biomarkers and clinical outcomes remains poorly understood. METHODS: HDL subclass distribution was quantified by nuclear magnetic resonance spectroscopy. Lecithin-cholesterol acyltransferase (LCAT) activity, cholesterol ester transfer protein (CETP) activity, and paraoxonase (PON-1) activity were assessed using fluorometric assays. HDL-cholesterol efflux capacity (CEC) was assessed in a validated assay using [3H]-cholesterol-labeled J774 macrophages. RESULTS: Among the study participants, 74 (23.5 %) out of 315 died within three months after hospitalization due to AHF. These patients exhibited lower activities of the anti-oxidant enzymes PON1 and LCAT, impaired CEC, and lower concentration of small HDL subclasses, which remained significant after accounting for potential confounding factors. Smaller HDL particles, particularly HDL3 and HDL4, exhibited a strong association with CEC, PON1 activity, and LCAT activity. CONCLUSIONS: In patients with AHF, impaired HDL CEC, HDL antioxidant and anti-inflammatory function, and impaired HDL metabolism are associated with increased mortality. Assessment of HDL function and subclass distribution could provide valuable clinical information and help identify patients at high risk.

Effects of dietary interventions and intermittent fasting on HDL function in obese individuals with T2DM: a randomized controlled trial.

BACKGROUND: Cardiovascular disease represents a significant risk factor for mortality in individuals with type 2 diabetes mellitus (T2DM). High-density lipoprotein (HDL) is believed to play a crucial role in maintaining cardiovascular health through its multifaceted atheroprotective effects and its capacity to enhance glycemic control. The impact of dietary interventions and intermittent fasting (IF) on HDL functionality remains uncertain. The objective of this study was to assess the effects of dietary interventions and IF as a strategy to safely improve glycemic control and reduce body weight on functional parameters of HDL in individuals with T2DM. METHODS: Before the 12-week intervention, all participants (n = 41) of the INTERFAST-2 study were standardized to a uniform basal insulin regimen and randomized to an IF or non-IF group. Additionally, all participants were advised to adhere to dietary recommendations that promoted healthy eating patterns. The IF group (n = 19) followed an alternate-day fasting routine, reducing their calorie intake by 75% on fasting days. The participants' glucose levels were continuously monitored. Other parameters were measured following the intervention: Lipoprotein composition and subclass distribution were measured by nuclear magnetic resonance spectroscopy. HDL cholesterol efflux capacity, paraoxonase 1 (PON1) activity, lecithin cholesterol acyltransferase (LCAT) activity, and cholesterol ester transfer protein (CETP) activity were assessed using cell-based assays and commercially available kits. Apolipoprotein M (apoM) levels were determined by ELISA. RESULTS: Following the 12-week intervention, the IF regimen significantly elevated serum apoM levels (p = 0.0144), whereas no increase was observed in the non-IF group (p = 0.9801). ApoM levels correlated with weight loss and fasting glucose levels in the IF group. Both groups exhibited a robust enhancement in HDL cholesterol efflux capacity (p < 0.0001, p = 0.0006) after 12 weeks. Notably, only the non-IF group exhibited significantly elevated activity of PON1 (p = 0.0455) and LCAT (p = 0.0117) following the 12-week intervention. In contrast, the changes observed in the IF group did not reach statistical significance. CONCLUSIONS: A balanced diet combined with meticulous insulin management improves multiple metrics of HDL function. While additional IF increases apoM levels, it does not further enhance other aspects of HDL functionality. TRIAL REGISTRATION: The study was registered at the German Clinical Trial Register (DRKS) on 3 September 2019 under the number DRKS00018070.

Rescue of Familial Lecithin:Cholesterol Acyltranferase Deficiency Mutations with an Allosteric Activator.

Lecithin:cholesterol acyltransferase (LCAT) deficiencies represent severe disorders characterized by aberrant cholesterol esterification in plasma, leading to life-threatening conditions. This study investigates the efficacy of Compound 2, a piperidinyl pyrazolopyridine allosteric activator that binds the membrane-binding domain of LCAT, in rescuing the activity of LCAT variants associated with disease. The variants K218N, N228K, and G230R, all located in the cap and lid domains of LCAT, demonstrated notable activity restoration in response to Compound 2. Molecular dynamics simulations and structural modeling indicate that these mutations disrupt the lid and membrane binding domain, with Compound 2 potentially dampening these structural alterations. Conversely, variants such as M252K and F382V in the cap and α/ß-hydrolase domain, respectively, exhibited limited or no rescue by Compound 2. Future research should prioritize in vivo investigations that would validate the therapeutic potential of Compound 2 and related activators in familial LCAT deficiency patients with mutations in the cap and lid of the enzyme. SIGNIFICANCE STATEMENT: Lecithin:cholesterol acyltranferase (LCAT) catalyzes the first step of reverse cholesterol transport, namely the esterification of cholesterol in high density lipoprotein particles. Somatic mutations in LCAT lead to excess cholesterol in blood plasma and, in severe cases, kidney failure. In this study, we show that recently discovered small molecule activators can rescue function in LCAT-deficient variants when the mutations occur in the lid and cap domains of the enzyme.

Low LCAT activity is linked to acute decompensated heart failure and mortality in patients with CKD.

Chronic kidney disease (CKD) is often associated with decreased activity of lecithin-cholesterol acyltransferase (LCAT), an enzyme essential for HDL maturation. This reduction in LCAT activity may potentially contribute to an increased risk of cardiovascular mortality in patients with CKD. The objective of this study was to investigate the association between LCAT activity in patients with CKD and the risk of adverse outcomes. We measured serum LCAT activity and characterized lipoprotein profiles using nuclear magnetic resonance spectroscopy in 453 non-dialysis CKD patients from the CARE FOR HOMe study. LCAT activity correlated directly with smaller HDL particle size, a type of HDL potentially linked to greater cardiovascular protection. Over a mean follow-up of 5.0 ± 2.2 years, baseline LCAT activity was inversely associated with risk of death (standardized HR 0.62, 95% CI 0.50-0.76; P < 0.001) and acute decompensated heart failure (ADHF) (standardized HR 0.67, 95% CI 0.52-0.85; P = 0.001). These associations remained significant even after adjusting for other risk factors. Interestingly, LCAT activity was not associated with the incidence of atherosclerotic cardiovascular events or kidney function decline during the follow-up. To conclude, our findings demonstrate that low LCAT activity is independently associated with all-cause mortality and ADHF in patients with CKD, and is directly linked to smaller, potentially more protective HDL subclasses.

A Novel Symptomatic Lecithin-Cholesterol Acyltransferase Gene Mutation With Corneal Amyloidosis.

PURPOSE: To present ocular clinical, histological, systemic, and genetic findings of a patient with familial lecithin-cholesterol acyltransferase (LCAT) deficiency caused by a novel genetic variant of the LCAT gene associated with secondary corneal amyloidosis. METHODS: Case report. RESULTS: A 74-year-old woman presented with decreased visual acuity (VA), sensitivity to light, and progressive whitening of both corneas for approximately 20 years. The patient had undergone penetrating keratoplasty (PKP) on the right eye 6 years ago. Ophthalmologic examination revealed decreased VA in both eyes (OD: 0.05, OS: 0.3), and even further reduced glare VA (OD: 0.05, OS: 0.1), diffuse whitish corneal opacity involving the total thickness of the corneal stroma without crystalline deposits, and a marked peripheral diffuse arcus. Systemic examination revealed severely reduced plasma high-density lipoprotein cholesterol levels, target cells in blood smear, and chronic normochromic anemia. Clinically, LCAT deficiency was the most likely diagnosis. Further genetic analysis confirmed the diagnosis. The patient is homozygous for the novel variant c.943T>C (p.Trp315Arg) in the LCAT gene. Histologic examination of the cornea removed during the first keratoplasty revealed amyloid deposits. The cornea removed at the second keratoplasty had small vacuoles in the anterior stroma, indicating recurrence of lipid deposition. CONCLUSIONS: LCAT deficiency is a rare genetic disorder that can cause corneal opacities because of lipid deposition in the cornea. Systemic manifestations may help in the differential diagnosis to other diseases associated with severe high-density lipoprotein cholesterol reduction. Genetic analysis is employed to confirm the diagnosis. Some mutations in the LCAT gene seem to be associated with secondary corneal amyloidosis. Further investigation of this association is warranted. A recurrence of corneal opacity after PKP seems to occur mainly in the anterior corneal stroma.

ALKBH5 regulates chicken adipogenesis by mediating LCAT mRNA stability depending on m6A modification.

BACKGROUND: Previous studies have demonstrated the role of N6-methyladenosine (m6A) RNA methylation in various biological processes, our research is the first to elucidate its specific impact on LCAT mRNA stability and adipogenesis in poultry. RESULTS: The 6 100-day-old female chickens were categorized into high (n = 3) and low-fat chickens (n = 3) based on their abdominal fat ratios, and their abdominal fat tissues were processed for MeRIP-seq and RNA-seq. An integrated analysis of MeRIP-seq and RNA-seq omics data revealed 16 differentially expressed genes associated with to differential m6A modifications. Among them, ELOVL fatty acid elongase 2 (ELOVL2), pyruvate dehydrogenase kinase 4 (PDK4), fatty acid binding protein 9 (PMP2), fatty acid binding protein 1 (FABP1), lysosomal associated membrane protein 3 (LAMP3), lecithin-cholesterol acyltransferase (LCAT) and solute carrier family 2 member 1 (SLC2A1) have ever been reported to be associated with adipogenesis. Interestingly, LCAT was down-regulated and expressed along with decreased levels of mRNA methylation methylation in the low-fat group. Mechanistically, the highly expressed ALKBH5 gene regulates LCAT RNA demethylation and affects LCAT mRNA stability. In addition, LCAT inhibits preadipocyte proliferation and promotes preadipocyte differentiation, and plays a key role in adipogenesis. CONCLUSIONS: In conclusion, ALKBH5 mediates RNA stability of LCAT through demethylation and affects chicken adipogenesis. This study provides a theoretical basis for further understanding of RNA methylation regulation in chicken adipogenesis.

Longitudinal analysis of clinical and laboratory biomarkers in a patient with familial lecithin: cholesterol acyltransferase deficiency (FLD) and accelerated eGFR decline: A case study.

Familial lecithin:cholesterol acyltransferase (LCAT) deficiency (FLD) is an ultra-rare autosomal recessive disease characterized by very low high-density lipoprotein cholesterol (HDL-C) levels, corneal opacity, anemia, and progressive renal disease. The rate and severity of renal disease are variable across FLD patients and the biomarkers and risk factors for disease progression are poorly understood. Here we report a 30 year-long comparative analysis of the clinical and laboratory biomarkers in an FLD patient with accelerated renal decline, who underwent two kidney and one liver transplantations. Results show that elevated triglyceride and non-HDL-C levels may promote the formation of LpX and accelerate renal function decline, whereas markers of anemia may be early predictors. Conversely, corneal opacity progresses at a steady rate and does not correlate with lipid, hematologic, or renal biomarkers. Our study suggests that monitoring of markers of anemia may aid the early detection and timely management of kidney disease with conservative therapies. Furthermore, it suggests that controlling hypercholesterolemia and hypertriglyceridemia may help improve renal disease prognosis.

Systematic evaluation of lecithin:cholesterol acyltransferase binding sites in apolipoproteins via peptide based nanodiscs: regulatory role of charged residues at positions 4 and 7.

Lecithin:cholesterol acyltransferase (LCAT) exhibits α-activity on high-density and ß-activity on low-density lipoproteins. However, the molecular determinants governing LCAT activation by different apolipoproteins remain elusive. Uncovering these determinants would offer the opportunity to design and explore advanced therapies against dyslipidemias. Here, we have conducted coarse-grained and all-atom molecular dynamics simulations of LCAT with nanodiscs made with α-helical amphiphilic peptides either derived from apolipoproteins A1 and E (apoA1 and apoE) or apoA1 mimetic peptide 22A that was optimized to activate LCAT. This study aims to explore what drives the binding of peptides to our previously identified interaction site in LCAT. We hypothesized that this approach could be used to screen for binding sites of LCAT in different apolipoproteins and would provide insights to differently localized LCAT activities. Our screening approach was able to discriminate apoA1 helixes 4, 6, and 7 as key contributors to the interaction with LCAT supporting the previous research data. The simulations provided detailed molecular determinants driving the interaction with LCAT: the formation of hydrogen bonds or salt bridges between peptides E4 or D4 and LCAT S236 or K238 residues. Additionally, salt bridging between R7 and D73 was observed, depending on the availability of R7. Expanding our investigation to diverse plasma proteins, we detected novel LCAT binding helixes in apoL1, apoB100, and serum amyloid A. Our findings suggest that the same binding determinants, involving E4 or D4 -S236 and R7-D73 interactions, influence LCAT ß-activity on low-density lipoproteins, where apoE and or apoB100 are hypothesized to interact with LCAT.

Effects of Recombinant Human Lecithin Cholesterol Acyltransferase on Lipoprotein Metabolism in Humans.

BACKGROUND: LCAT (lecithin cholesterol acyl transferase) catalyzes the conversion of unesterified, or free cholesterol, to cholesteryl ester, which moves from the surface of HDL (high-density lipoprotein) into the neutral lipid core. As this iterative process continues, nascent lipid-poor HDL is converted to a series of larger, spherical cholesteryl ester-enriched HDL particles that can be cleared by the liver in a process that has been termed reverse cholesterol transport. METHODS: We conducted a randomized, placebocontrolled, crossover study in 5 volunteers with atherosclerotic cardiovascular disease, to examine the effects of an acute increase of recombinant human (rh) LCAT via intravenous administration (300-mg loading dose followed by 150 mg at 48 hours) on the in vivo metabolism of HDL APO (apolipoprotein)A1 and APOA2, and the APOB100-lipoproteins, very low density, intermediate density, and low-density lipoproteins. RESULTS: As expected, recombinant human LCAT treatment significantly increased HDL-cholesterol (34.9 mg/dL; P≤0.001), and this was mostly due to the increase in cholesteryl ester content (33.0 mg/dL; P=0.014). This change did not affect the fractional clearance or production rates of HDL-APOA1 and HDL-APOA2. There were also no significant changes in the metabolism of APOB100-lipoproteins. CONCLUSIONS: Our results suggest that an acute increase in LCAT activity drives greater flux of cholesteryl ester through the reverse cholesterol transport pathway without significantly altering the clearance and production of the main HDL proteins and without affecting the metabolism of APOB100-lipoproteins. Long-term elevations of LCAT might, therefore, have beneficial effects on total body cholesterol balance and atherogenesis.

Estrogen Induces LCAT to Maintain Cholesterol Homeostasis and Suppress Hepatocellular Carcinoma Development.

Hepatocellular carcinoma (HCC) is an aggressive disease that occurs predominantly in men. Estrogen elicits protective effects against HCC development. Elucidation of the estrogen-regulated biological processes that suppress HCC could lead to improved prevention and treatment strategies. Here, we performed transcriptomic analyses on mouse and human liver cancer and identified lecithin cholesterol acyltransferase (LCAT) as the most highly estrogen-upregulated gene and a biomarker of favorable prognosis. LCAT upregulation inhibited HCC in vitro and in vivo and mediated estrogen-induced suppression of HCC in an ESR1-dependent manner. LCAT facilitated high-density lipoprotein cholesterol production and uptake via the LDLR and SCARB1 pathways. Consistently, high HDL-C levels corresponded to a favorable prognosis in HCC patients. The enhanced HDL-C absorption induced by LCAT impaired SREBP2 maturation, which ultimately suppressed cholesterol biosynthesis and dampened HCC cell proliferation. HDL-C alone inhibited HCC growth comparably to the cholesterol-lowering drug lovastatin, and SREBF2 overexpression abolished the inhibitory activity of LCAT. Clinical observations and cross-analyses of multiple databases confirmed the correlation of elevated LCAT and HDL-C levels to reduced cholesterol synthesis and improved HCC patient prognosis. Furthermore, LCAT deficiency mimicked whereas LCAT overexpression abrogated the tumor growth-promoting effects of ovariectomy in HCC-bearing female mice. Most importantly, HDL-C and LCAT delayed the development of subcutaneous tumors in nude mice, and HDL-C synergized with lenvatinib to eradicate orthotopic liver tumors. Collectively, this study reveals that estrogen upregulates LCAT to maintain cholesterol homeostasis and to dampen hepatocarcinogenesis. LCAT and HDL-C represent potential prognostic and therapeutic biomarkers for targeting cholesterol homeostasis as a strategy for treating HCC. Significance: Estrogen mediates the sex differences in hepatocellular carcinoma development by reducing cholesterol biosynthesis through activation of an LCAT/HDL-C axis, providing strategies for improving liver cancer prevention, prognosis, and treatment.

Impaired high-density lipoprotein function and endothelial barrier stability in severe anaphylaxis.

BACKGROUND: Growing evidence demonstrates the importance of high- and low-density lipoprotein cholesterol in certain immune and allergy-mediated diseases. OBJECTIVE: This study aimed to evaluate levels of high- and low-density lipoprotein cholesterol and apolipoproteins A1 and B in sera from a cohort of patients presenting with hypersensitivity reactions. We further assessed the function of high-density lipoprotein particles as well as their involvement in the molecular mechanisms of anaphylaxis. METHODS: Lipid profile determination was performed in paired (acute and baseline) serum samples from 153 patients. Thirty-eight experienced a non-anaphylactic reaction and 115 had an anaphylactic reaction (88 moderate and 27 severe). Lecithin cholesterol acyl transferase activity was assessed in patient sera, and we also evaluated macrophage cholesterol efflux in response to the serum samples. Last, the effect of anaphylactic-derived high-density lipoprotein (HDL) particles on the endothelial barrier was studied. Detailed methods are provided in the Methods section in this article's Online Repository available at www.jacionline.org. RESULTS: Serum samples from severe anaphylactic reactions show statistically significant low levels of HDL cholesterol, low-density lipoprotein cholesterol, and apolipoproteins A1 and B, which points to their possible role as biomarkers. Specifically, HDL particles play a protective role in cardiovascular diseases. Using functional human serum cell assays, we observed impaired capacity of apolipoprotein B-depleted serum to induce macrophage cholesterol efflux in severe anaphylactic reactions. In addition, purified HDL particles from human anaphylactic sera failed to stabilize and maintain the endothelial barrier. CONCLUSION: These results encourage further research on HDL functions in severe anaphylaxis, which may lead to new diagnostic and therapeutic strategies.

Association of Plasma Vitamins and Carotenoids, DNA Methylation of LCAT, and Risk of Age-Related Macular Degeneration.

Dysregulation of lipid metabolism has been implicated in age-related macular degeneration (AMD), the leading cause of blindness among the elderly. Lecithin cholesterol acyltransferase (LCAT) is an important enzyme responsible for lipid metabolism, which could be regulated by DNA methylation during the development of various age-related diseases. This study aimed to assess the association between LCAT DNA methylation and the risk of AMD, and to examine whether plasma vitamin and carotenoid concentrations modified this association. A total of 126 cases of AMD and 174 controls were included in the present analysis. LCAT DNA methylation was detected by quantitative real-time methylation-1specific PCR (qMSP). Circulating vitamins and carotenoids were measured using reversed-phase high-performance liquid chromatography (RP-HPLC). DNA methylation of LCAT was significantly higher in patients with AMD than those in the control subjects. After multivariable adjustment, participants in the highest tertile of LCAT DNA methylation had a 5.37-fold higher risk (95% CI: 2.56, 11.28) of AMD compared with those in the lowest tertile. Each standard deviation (SD) increment of LCAT DNA methylation was associated with a 2.23-fold (95% CI: 1.58, 3.13) increased risk of AMD. There was a J-shaped association between LCAT DNA methylation and AMD risk (Pnon-linearity = 0.03). Higher concentrations of plasma retinol and ß-cryptoxanthin were significantly associated with decreased levels of LCAT DNA methylation, with the multivariate-adjusted ß coefficient being -0.05 (95% CI: -0.08, -0.01) and -0.25 (95% CI: -0.42, -0.08), respectively. In joint analyses of LCAT DNA methylation and plasma vitamin and carotenoid concentrations, the inverse association between increased LCAT DNA methylation and AMD risk was more pronounced among participants who had a lower concentration of plasma retinol and ß-cryptoxanthin. These findings highlight the importance of comprehensively assessing LCAT DNA methylation and increasing vitamin and carotenoid status for the prevention of AMD.

Two Cases of Acquired High-Density Lipoprotein Deficiency with Immunoglobulin G4-Related Lecithin-Cholesterol Acyltransferase Autoantibody.

Lecithin-cholesterol acyltransferase (LCAT) plays a significant role in the progression from premature to mature high-density lipoprotein (HDL) in circulation. Consequently, primary or secondary LCAT deletion or reduction naturally results in low serum HDL cholesterol levels. Recently, rare cases of acquired HDL deficiency with LCAT autoantibodies have been reported, mainly from Japan, where LCAT autoantibodies of immunoglobulin G (IgG) caused the HDL deficiency. Here to our knowledge, we report for the first time two cases of acquired HDL deficiency caused by IgG4 linked LCAT autoantibodies with or without a high serum IgG4 level. Furthermore, these cases can extend to a new concept of "IgG4 autoimmune disease" from the viewpoint of verifying the serum autoantibody and/or renal histopathology.

Novel therapeutic opportunities for familial lecithin:cholesterol acyltransferase deficiency: promises and challenges.

PURPOSE OF REVIEW: Genetic lecithin:cholesterol acyltransferase (LCAT) deficiency is a rare, inherited, recessive disease, which manifests as two different syndromes: Familial LCAT deficiency (FLD) and Fish-eye disease (FED), characterized by low HDL-C and corneal opacity. FLD patients also develop anaemia and renal disease. There is currently no therapy for FLD, but novel therapeutics are at different stages of development. Here, we summarize the most recent advances and the opportunities for and barriers to the further development of such therapies. RECENT FINDINGS: Recent publications highlight the heterogeneous phenotype of FLD and the uncertainty over the natural history of disease and the factors contributing to disease progression. Therapies that restore LCAT function (protein and gene replacement therapies and LCAT activators) showed promising effects on markers of LCAT activity. Although they do not restore LCAT function, HDL mimetics may slow renal disease progression. SUMMARY: The further development of novel therapeutics requires the identification of efficacy endpoints, which include quantitative biomarkers of disease progression. Because of the heterogeneity of renal disease progression among FLD individuals, future treatments for FLD will have to be tailored based on the specific clinical characteristics of the patient. Extensive studies of the natural history and biomarkers of the disease will be required to achieve this goal.

Mechanistic Insights into the Activation of Lecithin-Cholesterol Acyltransferase in Therapeutic Nanodiscs Composed of Apolipoprotein A-I Mimetic Peptides and Phospholipids.

The mechanistic details behind the activation of lecithin-cholesterol acyltransferase (LCAT) by apolipoprotein A-I (apoA-I) and its mimetic peptides are still enigmatic. Resolving the fundamental principles behind LCAT activation will facilitate the design of advanced HDL-mimetic therapeutic nanodiscs for LCAT deficiencies and coronary heart disease and for several targeted drug delivery applications. Here, we have combined coarse-grained molecular dynamics simulations with complementary experiments to gain mechanistic insight into how apoA-Imimetic peptide 22A and its variants tune LCAT activity in peptide-lipid nanodiscs. Our results highlight that peptide 22A forms transient antiparallel dimers in the rim of nanodiscs. The dimerization tendency considerably decreases with the removal of C-terminal lysine K22, which has also been shown to reduce the cholesterol esterification activity of LCAT. In addition, our simulations revealed that LCAT prefers to localize to the rim of nanodiscs in a manner that shields the membrane-binding domain (MBD), αA-αA', and the lid amino acids from the water phase, following previous experimental evidence. Meanwhile, the location and conformation of LCAT in the rim of nanodiscs are spatially more restricted when the active site covering the lid of LCAT is in the open form. The average location and spatial dimensions of LCAT in its open form were highly compatible with the electron microscopy images. All peptide 22A variants studied here had a specific interaction site in the open LCAT structure flanked by the lid and MBD domain. The bound peptides showed different tendencies to form antiparallel dimers and, interestingly, the temporal binding site occupancies of the peptide variants affected their in vitro ability to promote LCAT-mediated cholesterol esterification.

Randomized, Placebo-Controlled Phase 2b Study to Evaluate the Safety and Efficacy of Recombinant Human Lecithin Cholesterol Acyltransferase in Acute ST-Segment-Elevation Myocardial Infarction: Results of REAL-TIMI 63B.

BACKGROUND: High-density lipoprotein plays a key role in reverse cholesterol transport. In addition, high-density lipoprotein particles may be cardioprotective and reduce infarct size in the setting of myocardial injury. Lecithin-cholesterol acyltransferase is a rate-limiting enzyme in reverse cholesterol transport. MEDI6012 is a recombinant human lecithin-cholesterol acyltransferase that increases high-density lipoprotein cholesterol. Administration of lecithin-cholesterol acyltransferase has the potential to reduce infarct size and regress coronary plaque in acute ST-segment-elevation myocardial infarction. METHODS: REAL-TIMI 63B (A Randomized, Placebo­controlled Phase 2b Study to Evaluate the Safety and Efficacy of MEDI6012 in Acute ST Elevation Myocardial Infarction) was a phase 2B multinational, placebo-controlled, randomized trial. Patients with ST-segment-elevation myocardial infarction within 6 hours of symptom onset and planned for percutaneous intervention were randomly assigned 2:1 to MEDI6012 (2- or 6-dose regimen) or placebo and followed for 12 weeks. The primary outcome was infarct size as a percentage of left ventricular mass by cardiac MRI at 10 to 12 weeks, with the primary analysis in patients with TIMI Flow Grade 0 to 1 before percutaneous intervention who received at least 2 doses of MEDI6012. The secondary outcome was change in noncalcified plaque volume on coronary computed tomographic angiography from baseline to 10 to 12 weeks with the primary analysis in patients who received all 6 doses of MEDI6012. RESULTS: A total of 593 patients were randomly assigned. Patients were a median of 62 years old, 77.9% male, and 95.8% statin naive. Median time from symptom onset to randomization was 146 (interquartile range [IQR], 103-221) minutes and from hospitalization to randomization was 12.7 (IQR, 6.6-24.0) minutes, and the first dose of drug was administered a median of 8 (IQR, 3-13) minutes before percutaneous intervention. The index myocardial infarction was anterior in 69.6% and TIMI Flow Grade 0 to 1 in 65.1% of patients. At 12 weeks, infarct size did not differ between treatment groups (MEDI6012: 9.71%, IQR 4.79-16.38; placebo: 10.48%, [IQR, 4.92-16.61], 1-sided P=0.79. There was also no difference in noncalcified plaque volume (geometric mean ratio, 0.96 [95% CI, NA-1.10], 1-sided P=0.30). There was no significant difference in treatment emergent serious adverse events. CONCLUSIONS: Administration of MEDI6012 in patients with acute ST-segment-elevation myocardial infarction did not result in a significant reduction in infarct size or noncalcified plaque volume at 12 weeks. MEDI6012 was well tolerated with no excess in overall serious adverse events. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03578809.

A novel homozygous frameshift mutation in the APOA1 gene associated with marked high-density lipoprotein deficiency.

The proband was a 53-year-old Japanese woman. Despite having no atherosclerotic vascular lesions on a physiological examination, markedly decreased levels of high-density lipoprotein (HDL) were always noted at her annual medical checkup. She also had corneal opacities but neither xanthoma nor tonsillar hypertrophy. A biochemical examination showed decreased levels of both apolipoprotein A-I (apoA-I) (<5 mg/dL) and lecithin-cholesterol acyltransferase (LCAT) activity. Her brother and son also had low concentrations of HDL-cholesterol, suggesting the presence of a genetic abnormality. Therefore, a sequence analysis of the genes for ABCA1, LCAT and apoA-I proteins was performed in the proband. The analysis of the APOA1 gene revealed a novel homozygous two-nucleotide deletion in exon 4 (c.614_615delTC), which causes a frameshift after residue 205 of the apoA-I protein (p.Leu205fs). Since no mutation has been found in the ABCA1 or LCAT gene, functional abnormalities of the carboxyl-terminal region of the apoA-I protein in lipid binding might have caused the low HDL-cholesterol levels and decreased LCAT activity, possibly associated with corneal opacities but not premature CAD, in the patient.

Lipidomic Approaches to Study HDL Metabolism in Patients with Central Obesity Diagnosed with Metabolic Syndrome.

The metabolic syndrome (MetS) is a cluster of cardiovascular risk factors characterised by central obesity, atherogenic dyslipidaemia, and changes in the circulating lipidome; the underlying mechanisms that lead to this lipid remodelling have only been partially elucidated. This study used an integrated "omics" approach (untargeted whole serum lipidomics, targeted proteomics, and lipoprotein lipidomics) to study lipoprotein remodelling and HDL composition in subjects with central obesity diagnosed with MetS (vs. controls). Compared with healthy subjects, MetS patients showed higher free fatty acids, diglycerides, phosphatidylcholines, and triglycerides, particularly those enriched in products of de novo lipogenesis. On the other hand, the "lysophosphatidylcholines to phosphatidylcholines" and "cholesteryl ester to free cholesterol" ratios were reduced, pointing to a lower activity of lecithin cholesterol acyltransferase (LCAT) in MetS; LCAT activity (directly measured and predicted by lipidomic ratios) was positively correlated with high-density lipoprotein cholesterol (HDL-C) and negatively correlated with body mass index (BMI) and insulin resistance. Moreover, many phosphatidylcholines and sphingomyelins were significantly lower in the HDL of MetS patients and strongly correlated with BMI and clinical metabolic parameters. These results suggest that MetS is associated with an impairment of phospholipid metabolism in HDL, partially led by LCAT, and associated with obesity and underlying insulin resistance. This study proposes a candidate strategy to use integrated "omics" approaches to gain mechanistic insights into lipoprotein remodelling, thus deepening the knowledge regarding the molecular basis of the association between MetS and atherosclerosis.

Plasma FA composition in familial LCAT deficiency indicates SOAT2-derived cholesteryl ester formation in humans.

Mutations in the LCAT gene cause familial LCAT deficiency (Online Mendelian Inheritance in Man ID: #245900), a very rare metabolic disorder. LCAT is the only enzyme able to esterify cholesterol in plasma, whereas sterol O-acyltransferases 1 and 2 are the enzymes esterifying cellular cholesterol in cells. Despite the complete lack of LCAT activity, patients with familial LCAT deficiency exhibit circulating cholesteryl esters (CEs) in apoB-containing lipoproteins. To analyze the origin of these CEs, we investigated 24 carriers of LCAT deficiency in this observational study. We found that CE plasma levels were significantly reduced and highly variable among carriers of two mutant LCAT alleles (22.5 [4.0-37.8] mg/dl) and slightly reduced in heterozygotes (218 [153-234] mg/dl). FA distribution in CE (CEFA) was evaluated in whole plasma and VLDL in a subgroup of the enrolled subjects. We found enrichment of C16:0, C18:0, and C18:1 species and a depletion in C18:2 and C20:4 species in the plasma of carriers of two mutant LCAT alleles. No changes were observed in heterozygotes. Furthermore, plasma triglyceride-FA distribution was remarkably similar between carriers of LCAT deficiency and controls. CEFA distribution in VLDL essentially recapitulated that of plasma, being mainly enriched in C16:0 and C18:1, while depleted in C18:2 and C20:4. Finally, after fat loading, chylomicrons of carriers of two mutant LCAT alleles showed CEs containing mainly saturated FAs. This study of CEFA composition in a large cohort of carriers of LCAT deficiency shows that in the absence of LCAT-derived CEs, CEs present in apoB-containing lipoproteins are derived from hepatic and intestinal sterol O-acyltransferase 2.

The impact of probiotic yogurt versus ordinary yogurt on serum sTWEAK, sCD163, ADMA, LCAT and BUN in patients with chronic heart failure: a randomized, triple-blind, controlled trial.

BACKGROUND: To date, no study has investigated the effects of probiotic yogurt as a functional food in patients with chronic heart failure (CHF). Therefore, the aim of this study was to compare the impact of probiotic yogurt versus ordinary yogurt on inflammatory, endothelial, lipid and renal indices in CHF patients. In this randomized, triple-blind clinical trial, 90 patients with CHF were randomly allocated into two groups to take either probiotic or ordinary yogurt for 10 weeks. Serum levels of soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK), soluble cluster of differentiation 163 (sCD163), asymmetric dimethylarginine (ADMA), and lecithin cholesterol acyltransferase (LCAT) were measured by using ELISA kits, and blood urea nitrogen (BUN) was measured by calorimetry method at baseline and at the end of trial. The P-value <0.05 was defined as statistically significant. RESULTS: Seventy-eight patients completed the study. At the end of the intervention, the levels of sTWEAK in both groups increased significantly, and this increase was greater in the probiotic yogurt group [691.84 (335.60, 866.95)] compared to control group [581.96 (444.99, 929.40)], and the difference between the groups was statistically significant after adjusting for confounders (P-value: 0.257, adjusted P-value: 0.038). However, no significant differences were found between the groups in the cases of other study indices. CONCLUSION: Probiotic yogurt may be useful for improving the inflammatory status in patients with CHF through increasing sTWEAK levels, however, further studies are needed in this area. © 2022 Society of Chemical Industry.