Lecithin-cholesterol acyltransferase and paraoxonase-1 levels in atherosclerotic cardiovascular disease patients in Nigeria.

Background: Recent evidence has linked changes in plasma lecithin-cholesterol acyltransferase (LCAT) and paraoxonase-1 (PON-1) levels with increased risk for development of premature atherosclerotic cardiovascular disease (ASCVD) in different populations. However, studies on this in Nigeria and sub-Saharan Africa are scarce. Objective: This study assessed the association between reduced plasma LCAT and PON-1 levels and an increased risk of ASCVD, and their potential as biomarkers for ASCVD. Methods: Atherosclerotic cardiovascular disease patients and healthy controls were randomly selected for this cross-sectional case-control study from the Lagos State University Teaching Hospital, Ikeja, Lagos, Nigeria, between March 2022 and March 2023. Plasma LCAT and PON-1 were determined by sandwich enzyme-linked immunosorbent assay, while the lipid profile was measured by spectrophotometry. Results: A total of 153 ASCVD patients (mean age: 52.92 ± 10.24 years) and 50 healthy controls (mean age: 46.96 ± 11.05 years) were included in the analyses. Stastistically significant increases were observed in the mean body weight, hip circumference, waist circumference, waist-to-hip ratio, body mass index, diastolic and systolic blood pressure (all p ≤ 0.001), and pulse rate (p = 0.003) compared to the control values. Statistically significant increases were also observed in the mean plasma total cholesterol, triglycerides, low-density lipoprotein cholesterol, and non-high-density lipoprotein cholesterol (all p ≤ 0.001). In contrast, the mean plasma high-density lipoprotein cholesterol, LCAT, and PON-1 (p ≤ 0.001) were notably reduced compared to the control values. Conclusion: The present study provides supportive evidence that changes in plasma LCAT and PON-1 could predispose individuals to risk of premature ASCVD. What this study adds: Plasma LCAT and PON-1 may serve as independent markers or complement other established cardiovascular disease markers to discriminate the risk of ASCVD when it is unclear.

Lecithin-cholesterol acyltransferase is a potential tumor suppressor and predictive marker for hepatocellular carcinoma metastasis.

BACKGROUND: Hepatocellular carcinoma (HCC) is a major cause of cancer mortality worldwide, and metastasis is the main cause of early recurrence and poor prognosis. However, the mechanism of metastasis remains poorly understood. AIM: To determine the possible mechanism affecting HCC metastasis and provide a possible theoretical basis for HCC treatment. METHODS: The candidate molecule lecithin-cholesterol acyltransferase (LCAT) was screened by gene microarray and bioinformatics analysis. The expression levels of LCAT in clinical cohort samples was detected by quantitative real-time polymerase chain reaction and western blotting. The proliferation, migration, invasion and tumor-forming ability were measured by Cell Counting Kit-8, Transwell cell migration, invasion, and clonal formation assays, respectively. Tumor formation was detected in nude mice after LCAT gene knockdown or overexpression. The immunohistochemistry for Ki67, E-cadherin, N-cadherin, matrix metalloproteinase 9 and vascular endothelial growth factor were performed in liver tissues to assess the effect of LCAT on HCC. Gene set enrichment analysis (GSEA) on various gene signatures were analyzed with GSEA version 3.0. Three machine-learning algorithms (random forest, support vector machine, and logistic regression) were applied to predict HCC metastasis in The Cancer Genome Atlas and GEO databases. RESULTS: LCAT was identified as a novel gene relating to HCC metastasis by using gene microarray in HCC tissues. LCAT was significantly downregulated in HCC tissues, which is correlated with recurrence, metastasis and poor outcome of HCC patients. Functional analysis indicated that LCAT inhibited HCC cell proliferation, migration and invasion both in vitro and in vivo. Clinicopathological data showed that LCAT was negatively associated with HCC size and metastasis (HCC size ≤ 3 cm vs 3-9 cm, P < 0.001; 3-9 cm vs > 9 cm, P < 0.01; metastatic-free HCC vs extrahepatic metastatic HCC, P < 0.05). LCAT suppressed the growth, migration and invasion of HCC cell lines via PI3K/AKT/mTOR signaling. Our results indicated that the logistic regression model based on LCAT, TNM stage and the serum level of α-fetoprotein in HCC patients could effectively predict high metastatic risk HCC patients. CONCLUSION: LCAT is downregulated at translational and protein levels in HCC and might inhibit tumor metastasis via attenuating PI3K/AKT/mTOR signaling. LCAT is a prognostic marker and potential therapeutic target for HCC.

Lecithin and cardiovascular health: a comprehensive review.

BACKGROUND: Cardiovascular diseases are one of the prime causes of mortality globally. Therefore, concerted efforts are made to prevent or manage disruptions from normal functioning of the cardiovascular system. Disruption in lipid metabolism is a major contributor to cardiovascular dysfunction. This review examines how lecithin impacts lipid metabolism and cardiovascular health. It emphasizes lecithin's ability to reduce excess low-density lipoproteins (LDL) while specifically promoting the synthesis of high-density lipoprotein (HDL) particles, thus contributing to clearer understanding of its role in cardiovascular well-being. Emphasizing the importance of lecithin cholesterol acyltransferase (LCAT) in the reverse cholesterol transport (RCT) process, the article delves into its contribution in removing surplus cholesterol from cells. This review aims to clarify existing literature on lipid metabolism, providing insights for targeted strategies in the prevention and management of atherosclerotic cardiovascular disease (ASCVD). This review summarizes the potential of lecithin in cardiovascular health and the role of LCAT in cholesterol metabolism modulation, based on articles from 2000 to 2023 sourced from databases like MEDLINE, PubMed and the Scientific Electronic Library Online. MAIN BODY: While studies suggest a positive correlation between increased LCAT activities, reduced LDL particle size and elevated serum levels of triglyceride-rich lipoprotein (TRL) markers in individuals at risk of ASCVD, the review acknowledges existing controversies. The precise nature of LCAT's potential adverse effects remains uncertain, with varying reports in the literature. Notably, gastrointestinal symptoms such as diarrhea and nausea have been sporadically documented. CONCLUSIONS: The review calls for a comprehensive investigation into the complexities of LCAT's impact on cardiovascular health, recognizing the need for a nuanced understanding of its potential drawbacks. Despite indications of potential benefits, conflicting findings warrant further research to clarify LCAT's role in atherosclerosis.

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 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 2 kidney and one liver transplantations. Results show that elevated TG 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.

Familial LCAT Deficiency and Low HDL-C Levels: In silico Characterization of Two Rare LCAT Missense Mutations.

Mutations in the lecithin-cholesterol acyltransferase (LCAT) gene, which catalyzes the esterification of cholesterol, result in two types of autosomal recessive disorders: Familial LCAT deficiency (FLD) and Fish Eye Disease (FED). While both phenotypes are characterized by corneal opacities and different forms of dyslipidemia, such as low levels of high-density lipoprotein-cholesterol (HDL-C), FLD exhibits more severe clinical manifestations like splenomegaly, anemia, and renal failure. We describe the first clinically and genetically confirmed case of FLD in Colombia which corresponds to a 46-year-old woman with corneal opacity, hypothyroidism, and dyslipidemia, who does not have any manifestations of renal failure, with two pathogenic heterozygous missense variants in the LCAT gene: LCAT (NM_000229.2):c.803G>A (p.Arg268His) and LCAT (NM_000229.2):c.368G>C (p.Arg123Pro). In silico analysis of the mutations predicted the physicochemical properties of the mutated protein, causing instability and potentially decreased LCAT function. These compound mutations highlight the clinical heterogeneity of the phenotypes associated with LCAT gene mutations.

Apolipoprotein E isoforms differentially affect LCAT-dependent cholesterol esterification.

BACKGROUND AND AIMS: LCAT esterifies cholesterol in both HDL (α-activity) and apoB-containing lipoproteins (ß-activity). The main activator of LCAT ß-activity is apoE, which in humans exists in 3 main different isoforms (E2, E3 and E4). Here, to gather insights into the potential role of LCAT in apoB-containing lipoprotein metabolism, we investigated the ability of apoE isoforms to promote LCAT-mediated cholesterol esterification. METHODS: We evaluated the plasma cholesterol esterification rate (CER) in 311 individuals who express functional LCAT and either apoE2, apoE3, or apoE4 and in 28 individuals who also carried LCAT mutations causing selective loss of LCAT α-activity (Fish-Eye Disease (FED)-causing mutations). The association of carrier status with CER was determined using an adjusted linear regression model. The kinetic of LCAT activity towards reconstituted HDLs (rHDLs) containing each apoE isoform was determined using the Michaelis-Menten model. RESULTS: Plasma CER was ∼20% higher in apoE2 carriers compared to apoE3 carriers, and ∼30% higher in apoE2 carriers compared to apoE4 carriers. After adjusting for age, sex, total cholesterol, HDL-C, apoA-I, apoB, chronic kidney disease diagnosis, zygosity, and LCAT concentration, CER remained significantly different among carriers of the three apoE isoforms. The same trend was observed in carriers of FED-causing mutations. rHDLs containing apoE2 were associated with a lower affinity but higher maximal esterification rate, compared to particles containing apoE3 or apoE4. CONCLUSION: The present results suggest that the apoE2 isoform is associated with a higher LCAT-mediated cholesterol esterification. This observation may contribute to the characterization of the peculiar functional properties of apoE2.

Lipid profile, ox-LDL, and LCAT activity in patients with endometrial carcinoma and type 2 diabetes: The effect of concurrent disease based on a case-control study.

Background and Aim: The role of lecithin: cholesterol acyltransferase (LCAT) and oxidized low-density lipoprotein (ox-LDL) in endometrial cancer (EC) or EC with concurrent type 2 diabetes is still unclear. This study investigated the LCAT activity, ox-LDL, and lipid profile in EC patients with or without type 2 diabetes and compared them with healthy individuals and patients with type 2 diabetes alone. Methods: In this cross-sectional, case-control study, 93 female participants were recruited. The participants were divided into four groups, including EC with type 2 diabetes (n = 19), EC without type 2 diabetes (n = 17), type 2 diabetes (n = 31), and healthy controls (n = 26). Sociodemographic information, the LCAT activity, triglyceride (TG), total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and ox-LDL levels were collected. One-way analysis of variance and analysis of covariance, Student's t-test, Mann-Whitney U-test, and χ 2-test were used to compare demographic features and laboratory results among studied groups. Regression analyses were also performed to evaluate the interaction effect between EC and type 2 diabetes on serum LCAT activity. Results: The LCAT activity was significantly lower, and ox-LDL levels were significantly higher in all patient groups compared to the healthy controls (p < 0.001). EC patients had significantly lower LCAT activity and higher ox-LDL levels than type 2 diabetes and healthy groups (p < 0.05). Higher levels of TG and lower levels of HDL-C were observed in all patient groups compared to the healthy group (all p < 0.001). Patients with EC and concomitant type 2 diabetes had significantly lower serum LDL-C levels than healthy and type 2 diabetes groups (p < 0.05). Conclusions: The combination of EC and type 2 diabetes had a subadditive effect on LCAT activity and ox-LDL level. The lowest LCAT activity and the highest ox-LDL levels were observed in patients with EC and concurrent type 2 diabetes.

Plasma and cerebrospinal fluid cholesterol esterification is hampered in Alzheimer's disease.

OBJECTIVE: The purpose of this study was to evaluate cholesterol esterification and HDL subclasses in plasma and cerebrospinal fluid (CSF) of Alzheimer's disease (AD) patients. METHODS: The study enrolled 70 AD patients and 74 cognitively normal controls comparable for age and sex. Lipoprotein profile, cholesterol esterification, and cholesterol efflux capacity (CEC) were evaluated in plasma and CSF. RESULTS: AD patients have normal plasma lipids but significantly reduced unesterified cholesterol and unesterified/total cholesterol ratio. Lecithin:cholesterol acyltransferase (LCAT) activity and cholesterol esterification rate (CER), two measures of the efficiency of the esterification process, were reduced by 29% and 16%, respectively, in the plasma of AD patients. Plasma HDL subclass distribution in AD patients was comparable to that of controls but the content of small discoidal preß-HDL particles was significantly reduced. In agreement with the reduced preß-HDL particles, cholesterol efflux capacity mediated by the transporters ABCA1 and ABCG1 was reduced in AD patients' plasma. The CSF unesterified to total cholesterol ratio was increased in AD patients, and CSF CER and CEC from astrocytes were significantly reduced in AD patients. In the AD group, a significant positive correlation was observed between plasma unesterified cholesterol and unesterified/total cholesterol ratio with Aß1-42 CSF content. CONCLUSION: Taken together our data indicate that cholesterol esterification is hampered in plasma and CSF of AD patients and that plasma cholesterol esterification biomarkers (unesterified cholesterol and unesterified/total cholesterol ratio) are significantly associated to disease biomarkers (i.e., CSF Aß1-42).

Deciphering structural aspects of reverse cholesterol transport: mapping the knowns and unknowns.

Atherosclerosis is a major contributor to the onset and progression of cardiovascular disease (CVD). Cholesterol-loaded foam cells play a pivotal role in forming atherosclerotic plaques. Induction of cholesterol efflux from these cells may be a promising approach in treating CVD. The reverse cholesterol transport (RCT) pathway delivers cholesteryl ester (CE) packaged in high-density lipoproteins (HDL) from non-hepatic cells to the liver, thereby minimising cholesterol load of peripheral cells. RCT takes place via a well-organised interplay amongst apolipoprotein A1 (ApoA1), lecithin cholesterol acyltransferase (LCAT), ATP binding cassette transporter A1 (ABCA1), scavenger receptor-B1 (SR-B1), and the amount of free cholesterol. Unfortunately, modulation of RCT for treating atherosclerosis has failed in clinical trials owing to our lack of understanding of the relationship between HDL function and RCT. The fate of non-hepatic CEs in HDL is dependent on their access to proteins involved in remodelling and can be regulated at the structural level. An inadequate understanding of this inhibits the design of rational strategies for therapeutic interventions. Herein we extensively review the structure-function relationships that are essential for RCT. We also focus on genetic mutations that disturb the structural stability of proteins involved in RCT, rendering them partially or completely non-functional. Further studies are necessary for understanding the structural aspects of RCT pathway completely, and this review highlights alternative theories and unanswered questions.

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.

Oxidative stress and antioxidant markers in patients with alopecia areata: A comparative cross-sectional study.

Background Alopecia areata is a chronic inflammatory skin disease. Oxidative stress may contribute to the pathogenesis of this condition. Aim To evaluate the serum oxidative stress markers and antioxidant capacity in patients with alopecia areata. Methods This cross-sectional study was performed on 40 patients with alopecia areata and 40 healthy controls. The fasting blood sugar, C-reactive protein, lipid profile, and serum oxidative markers, including advanced glycation end products and advanced oxidation protein products, were measured in this study. Also, antioxidant enzymes, including paraoxonase-1, lecithin-cholesterol acyltransferase and serum ferric-reducing antioxidant power, were determined. Results The serum levels of advanced glycation end products and advanced oxidation protein products were significantly higher in patients with alopecia areata, compared to the controls (P < 0.001), whereas the levels of ferric-reducing antioxidant power, paraoxonase-1 and lecithin-cholesterol acyltransferase were significantly lower in patients with alopecia areata, compared to the controls (P < 0.001). The mean fasting blood sugar level was significantly higher in patients with alopecia areata, compared to the controls. The ferric reducing antioxidant power level was significantly associated with the percentage of hair loss (P = 0.01, r = 0.4) and the serum C-reactive protein level (P = 0.03, r = -0.3) in patients with alopecia areata. Limitations Since the current study had a cross-sectional design, no cause-effect relationship was established between alopecia areata and oxidative stress. The sample size of our study was also small. Conclusion Based on the present results, the oxidant-antioxidant enzymatic system is impaired in alopecia areata due to the increased oxidative products and decreased antioxidant activity.

Effects of superoxide anion attack on the lipoprotein HDL.

High-density lipoprotein (HDL) is an anti-atherosclerotic lipoprotein. Thanks to the activity of apolipoprotein ApoA1, the principal protein component of HDL, this last is responsible for converting cholesterol into ester form and transporting excessive cholesterol to the liver ("reverse cholesterol transport" RCT). When HDL undergoes oxidation, it becomes dysfunctional and proatherogenic. ApoA1 is a target of oxidation, and its alteration affects RCT and contributes to atherosclerosis development. Until now, the mechanism of HDL oxidation is not fully understood and only hydroxyl radicals seem to induce direct oxidation of protein and lipidic components of lipoproteins. Here we demonstrate that superoxide radical, widely produced in early atherosclerosis, directly oxidizes HDL, and as a consequence, ApoA1 undergoes structural alterations impairing its anti-atherosclerotic functions. Our results highlight in an in vitro system the potential mechanism by which O2·- triggers atherosclerotic pathogenesis in vivo. Our study gets the basis for therapeutic approaches focused on the management of superoxide generation in early atherosclerosis onset.

Focal segmental glomerulosclerosis in a patient with congenital lecithin-cholesterol acyltransferase deficiency

Lecithin-cholesterol acyltransferase deficiency is a rare genetic disease caused by a mutation of the gene coding for the lecithin-cholesterol acyltransferase protein, and mainly affects low density lipoprotein metabolism. It typically manifests with diffuse corneal opacities, normocytic anemia and kidney disease. We present the case of a 30-year-old man with chronic kidney disease and nephrotic syndrome. His initial kidney biopsy showed focal segmental glomerulosclerosis, thought to be primary, a disease which was refractory to multiple immunosuppressive schemes. Manifestations such as anemia, splenomegaly, corneal opacities and an association with low high-density lipoproteins alerted to the possibility of glomerular damage secondary to lecithin-cholesterol acyltransferase enzyme deficiency, which was confirmed through genetic sequenc ing. Due to the low incidence of the disease, diagnosis is a clinical challenge. The signs and symptoms tend to be interpreted as isolated events, which significantly delays its confirmation. Understanding this entity and the clinical exercise needed to arrive at its diagnosis will serve as a reference, resulting in the suspicion and reporting of cases in the future. (Acta Med Colomb 2022; 47. DOI:https://doi.org/10.36104/amc.2022.2558).

La deficiencia de lecitin-colesterol aciltransferasa es una enfermedad genética rara, causada por una mutación en el gen que codifica la proteína lecitin-colesterol aciltransferasa y afecta principalmente el metabolismo de las lipoproteínas de baja densidad. Se manifiesta típicamente con opacidades corneales difusas, anemia normocítica y enfermedad renal. Se presenta el caso de un hombre de 30 años con enfermedad renal crónica y síndrome nefrótico, con biopsia renal inicial que demostró un patrón de glomeruloesclerosis focal y segmentaria, interpretada como primaria, enfermedad que fue refractaria a múltiples esquemas de inmunosupresión. Las manifestaciones como anemia, esplenomegalia, opacidades corneales y la asociación con lipoproteínas de alta densidad bajas, alertaron sobre la posibilidad de compromiso glomerular secundario a un déficit de la enzima lecitin-colesterol aciltransferasa, confirmado mediante estudio de secuenciación genética. Dada la baja incidencia de la enfermedad, el diagnóstico representa un desafío clínico. Las manifestaciones suelen interpretarse como eventos aislados, lo que lleva a retraso significativo en su confirmación. El conocimiento de esta entidad y el ejercicio clínico necesario para llegar al diagnóstico, servirán como referencia que derive en la sospecha y reporte de futuros casos. (Acta Med Colomb 2022; 47. DOI:https://doi.org/10.36104/amc.2022.2558).

HDL metabolism and functions impacting on cell cholesterol homeostasis are specifically altered in patients with abdominal aortic aneurysm.

Background: The etiopathogenesis of abdominal aortic aneurysm (AAA) is still unclarified, but vascular inflammation and matrix metalloproteases activation have a recognized role in AAA development and progression. Circulating lipoproteins are involved in tissue inflammation and repair, particularly through the regulation of intracellular cholesterol, whose excess is associated to cell damage and proinflammatory activation. We analyzed lipoprotein metabolism and function in AAA and in control vasculopathic patients, to highlight possible non-atherosclerosis-related, specific abnormalities. Methods: We measured fluorometrically serum esterified/total cholesterol ratio, as an index of lecithin-cholesterol acyltransferase (LCAT) activity, and cholesteryl ester transfer protein (CETP) activity in patients referred to vascular surgery either for AAA (n=30) or stenotic aortic/peripheral atherosclerosis (n=21) having similar burden of cardiovascular risk factors and disease. We measured high-density lipoprotein (HDL)-cholesterol efflux capacity (CEC), through the ATP-binding cassette G1 (ABCG1) and A1 (ABCA1) pathways and serum cell cholesterol loading capacity (CLC), by radioisotopic and fluorimetric methods, respectively. Results: We found higher LCAT (+23%; p < 0.0001) and CETP (+49%; p < 0.0001) activity in AAA sera. HDL ABCG1-CEC was lower (-16%; p < 0.001) and ABCA1-CEC was higher (+31.7%; p < 0.0001) in AAA. Stratification suggests that smoking may partly contribute to these modifications. CEC and CETP activity correlated with CLC only in AAA. Conclusions: We demonstrated that compared to patients with stenotic atherosclerosis, patients with AAA had altered HDL metabolism and functions involved in their anti-inflammatory and tissue repair activity, particularly through the ABCG1-related intracellular signaling. Clarifying the relevance of this mechanism for AAA evolution might help in developing new diagnostic parameters and therapeutic targets for the early management of this condition.

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.

LCAT-trial-24 weeks: Protocol for a clinical study to evaluate the safety of regenerative medicine and gene therapy by the autologous transplantation of human lecithin:cholesterol acyltransferase gene-transduced human pre-adipocytes.

Backgrounds: Despite the absolute need for life-long treatment of inherited and genetic diseases, there has been little effort to develop such treatments for most of these conditions due to their rarity. Familial lecithin:cholesterol acyltransferase (LCAT) deficiency is recognized as one such orphan disease. We have been developing an adipocyte-based ex vivo gene therapy/regenerative medicine, a novel methodology that differs from the adeno-associated virus-mediated in vivo gene therapy or ex vivo gene-transduced hematopoietic cell therapy, to treat familial LCAT deficiency. Recently, a first-in-human (FIH) clinical study was conducted under the Act on Securement of Safety of Regenerative Medicine, wherein a patient with familial LCAT deficiency was treated. To obtain approval to put this treatment into practical use, a clinical trial has been designed with reference to the FIH clinical study. Methods: An interventional, open-label, unblinded dose-escalation trial was planned, referring to previous FIH clinical study. The trial aims to evaluate the safety of the investigational product in relation to the characteristics of the investigational product (ex vivo gene/cell therapy product by retroviral vector-mediated LCAT gene transduction) using two doses, and the efficacy of the treatment will be evaluated exploratively. A total of three patients will be enrolled sequentially and followed for 24 weeks after administration. This study is designed as a multicenter trial, with Chiba University Hospital administering and evaluating the safety/efficacy of the investigational products at the prescribed visit. Conclusion: This clinical trial is expected to facilitate the provision of lifelong treatment to many patients with LCAT deficiency. Trial registration number: Japan Registry of Clinical Trials (jRCT2033200096).

Defects in a liver-bone axis contribute to hepatic osteodystrophy disease progression.

Hepatic osteodystrophy (HOD) is a metabolic bone disease that is often associated with chronic liver disease and is marked by bone loss. Here, we demonstrate that hepatic expression of the phosphatase PP2Acα is upregulated during HOD, leading to the downregulation of expression of the hepatokine lecithin-cholesterol acyltransferase (LCAT). Loss of LCAT function markedly exacerbates the bone loss phenotype of HOD in mice. In addition, we found that alterations in cholesterol levels are involved in the regulation of osteoblast and osteoclast activities. We also found that LCAT improves liver function and relieves liver fibrosis in the mouse HOD model by promoting reversal of cholesterol transport from the bone to the liver. In summary, defects in a liver-bone axis occur during HOD that can be targeted to ameliorate disease progression.

Familial lecithin-cholesterol acyltransferase deficiency: If so rare, why so frequent in the state of Piauí, northeastern Brazil?

Lecithin-cholesterol acyltransferase (LCAT), an enzyme that participates in lipoprotein metabolism, plays an important role in cholesterol homeostasis. Mutations in the LCAT gene can cause two rare genetic disorders: familial LCAT deficiency (FLD), which is characterized by corneal opacities, normocytic anemia, dyslipidemia, and proteinuria progressing to chronic renal failure, and fish-eye disease (FED), which causes dyslipidemia and progressive corneal opacities. Herein, we report six suspected cases of FLD in the backlands of Piauí, located in northeast Brazil. A genetic diagnosis was performed in index cases. Among these, a further investigation was performed to identify new cases in the families. In addition, molecular analyses were performed to verify the levels of consanguinity within families and the existence of a genetic relationship between them. All six index cases were confirmed as FLD with an identical mutation (c.803G > A, p.R268H). The genetic investigation confirmed another 7 new cases of FLD, 52 heterozygous and 6 individuals without mutations. The rate of consanguinity revealed that marriages within the family did not contribute to the high number of FLD cases within the restricted region. The elders of each family (patriarchs and matriarchs) were subjected to a kinship analysis and were more genetically related to each other than the control group. Bayesian analysis was implemented to confirm the hypothesis of connectivity among patriarchs and matriarchs and indicated that they were genetically more related to each other than would be randomly expected, thus suggesting the occurrence of a possible founder effect in these families.

LCAT- targeted therapies: Progress, failures and future.

Lecithin: cholesterol acyltransferase (LCAT) is the only enzyme in plasma which is able to esterify cholesterol and boost cholesterol esterify with phospholipid-derived acyl chains. In order to better understand the progress of LCAT research, it is always inescapable that it is linked to high-density lipoprotein (HDL) metabolism and reverse cholesterol transport (RCT). Because LCAT plays a central role in HDL metabolism and RCT, many animal studies and clinical studies are currently aimed at improving plasma lipid metabolism by increasing LCAT activity in order to find better treatment options for familial LCAT deficiency (FLD), fish eye disease (FED), and cardiovascular disease. Recombinant human LCAT (rhLCAT) injections, cells and gene therapy, and small molecule activators have been carried out with promising results. Recently rhLCAT therapies have entered clinical phase II trials with good prospects. In this review, we discuss the diseases associated with LCAT and therapies that use LCAT as a target hoping to find out whether LCAT can be an effective therapeutic target for coronary heart disease and atherosclerosis. Also, probing the mechanism of action of LCAT may help better understand the heterogeneity of HDL and the action mechanism of dynamic lipoprotein particles.

A systematic review of the natural history and biomarkers of primary lecithin:cholesterol acyltransferase deficiency.

Syndromes associated with LCAT deficiency, a rare autosomal recessive condition, include fish-eye disease (FED) and familial LCAT deficiency (FLD). FLD is more severe and characterized by early and progressive chronic kidney disease (CKD). No treatment is currently available for FLD, but novel therapeutics are under development. Furthermore, although biomarkers of LCAT deficiency have been identified, their suitability to monitor disease progression and therapeutic efficacy is unclear, as little data exist on the rate of progression of renal disease. Here, we systematically review observational studies of FLD, FED, and heterozygous subjects, which summarize available evidence on the natural history and biomarkers of LCAT deficiency, in order to guide the development of novel therapeutics. We identified 146 FLD and 53 FED patients from 219 publications, showing that both syndromes are characterized by early corneal opacity and markedly reduced HDL-C levels. Proteinuria/hematuria were the first signs of renal impairment in FLD, followed by rapid decline of renal function. Furthermore, LCAT activity toward endogenous substrates and the percentage of circulating esterified cholesterol (EC%) were the best discriminators between these two syndromes. In FLD, higher levels of total, non-HDL, and unesterified cholesterol were associated with severe CKD. We reveal a nonlinear association between LCAT activity and EC% levels, in which subnormal levels of LCAT activity were associated with normal EC%. This review provides the first step toward the identification of disease biomarkers to be used in clinical trials and suggests that restoring LCAT activity to subnormal levels may be sufficient to prevent renal disease progression.