👤 Luís Masana

Lipoprotein(a) (Lp(a)) is a proatherogenic particle that is considered an important cardiovascular risk modifier due to its association with atherosclerotic cardiovascular disease (ASCVD) as well as calcific aortic valve stenosis (CAVS). Data on the clinical burden associated with elevated lipoprotein(a) levels in patients at high and very high cardiovascular risk remain limited. We evaluated the prevalence of ASCVD and LDL-C target achievement in subjects with high and very high elevated Lp(a) levels referred to a lipid unit. In this retrospective study, 1755 subjects were evaluated; 265 with Lp(a) ≥240nmol/L were included. The population was divided into two groups: high Lp(a) (240-429nmol/L, n=216) and very high Lp(a) (≥430nmol/L, n=49). ASCVD prevalence was 58% in the very high group and 48% in the high group (p=0.23). Age and statin intensity were higher in the very high Lp(a) group. LDL-C target achievement was low in both groups: 20.0% and 25.4% of very high-risk patients reached <55mg/dL as well as 18.2% and 17.2% of high-risk patients reached <70mg/dL in very high and high Lp(a) groups, respectively. Subjects with elevated Lp(a) levels showed a high prevalence of ASCVD and low LDL-C target attainment despite high-intensity statin therapy. These findings support the need for Lp(a) screening and additional lipid-lowering strategies in high-risk patients. Show less

Homozygous familial hypercholesterolemia (HoFH) is a rare disease characterized by the presence of 2 pathogenic variants in the LDLR, APOB, PCSK9, or LDLRAP1 genes, which cause very high levels of LDL-cholesterol and premature atherosclerotic cardiovascular disease (ASCVD). To analyze the current situation regarding diagnosis, cardiovascular disease, lipid-lowering treatment, and degree of control of lipids in patients with HoFH in the National Dyslipidemia Registry of the Spanish Atherosclerosis Society. Subjects with HoFH, confirmed by the presence of 2 pathogenic variants in the genes mentioned above, included in the registry from 2013 to June 2023 with an updated review were analyzed. Of 71 included subjects with HoFH, 40.8% were women, aged 52 [24-62] years, 57 adults and 13 children. The median follow-up was 7 [4-13] years. Age of diagnosis was 14 [2-26] years, with 10% of ASCVD at diagnosis and 27% of current ASCVD at 40.6 (13.4) years of age; 38% were on PCSK9 inhibitors, 9 patients on lomitapide, 9 on LDL apheresis, and 1 patient on evinacumab. Subjects with more than 4 therapies achieved >80% reduction in LDLc. In the last visit, the median LDLc was 139.3 [89.4-204.2] mg/dL. ASCVD was strongly associated with male sex and family history of ASCVD, relative risk 5.26 (1.53-18.10) and 2.53 (1.03-6.26), P < .05, respectively. Only 18% and 10% meet the recommended LDLc goal in primary and secondary prevention respectively. The current situation of HoFH in Spain is better than expected, with marked reductions in LDLc levels with new treatments. In this population, recommended LDLc goals are difficult to achieve despite maximum lipid-lowering therapy. ASCVD has been reduced and delayed by 2 decades. Show less

Preclinical studies suggest that a triglyceride (TG)-independent proinflammatory action of apolipoprotein C-III (apoCIII) exists. We aimed to investigate the relationship between circulating apoCIII levels and subclinical inflammation markers across different cohorts with distinctive inflammatory patterns: patients with metabolic disorders (MDs), patients with rheumatoid arthritis (RA), and controls. Specifically, we assessed the associations of apoCIII with acute inflammation biomarkers (e.g., high sensitivity C-reactive protein (hsCRP)) and novel systemic inflammation biomarkers (e.g., glycosylated proteins: Glyc-A, Glyc-B, Glyc-F), aiming to understand the role of apoCIII beyond its traditional function in TG metabolism. This cross-sectional study involved 1242 participants: 906 patients with MD (metabolic syndrome, type 2 diabetes (T2DM) and/or obesity), 192 patients with RA, and 144 controls. ApoCIII and hsCRP levels were measured via immunoturbidimetric assays, and glycosylated proteins were quantified via 1 H-NMR spectroscopy. Correlation and multivariate linear regression analyses were conducted. ApoCIII levels were significantly and positively associated with Glyc-A, Glyc-B, and Glyc-F levels across all cohorts. Most of these associations remained significant in the MD group after adjusting for TG levels. Conversely, negative associations were detected between apoCIII and hsCRP patients with MD and RA, which were maintained after including TG in the models. In patients with MD and RA, circulating apoCIII levels were positively associated with glycoproteins and negatively with hsCRP, in a TG-independent manner. Our results suggest that apoCIII is associated with the low-grade inflammatory profile represented by glycoproteins, independent of triglyceride levels. Additionally, we observed a negative association with hsCRP, which, while seemingly paradoxical, has been reported in previous studies. Show less

Despite the various therapeutic tools available, many patients do not achieve therapeutic goals, and cardiovascular diseases remain a significant cause of death in our setting. Furthermore, even in patients who manage to reduce their LDL-C levels to the recommended targets, cardiovascular events continue to occur. The therapeutic challenge and the persistent risk have led to active research into new drugs targeting novel therapeutic pathways in the field of lipoprotein metabolism disorders. The therapeutic approach involves new pharmacological mechanisms, ranging from small molecules and monoclonal antibodies to RNA interference, with inclisiran being the first drug approved for clinical use in the cardiovascular domain. In this review, we aim to provide a comprehensive overview of the new therapeutic targets and pharmacological mechanisms under development, as well as their potential clinical impact. Show less

The HDL (high-density lipoprotein)-mediated stimulation of cellular cholesterol efflux initiates macrophage-specific reverse cholesterol transport (m-RCT), which ends in the fecal excretion of macrophage-derived unesterified cholesterol (UC). Early studies established that LDL (low-density lipoprotein) particles could act as efficient intermediate acceptors of cellular-derived UC, thereby preventing the saturation of HDL particles and facilitating their cholesterol efflux capacity. However, the capacity of LDL to act as a plasma cholesterol reservoir and its potential impact in supporting the m-RCT pathway in vivo both remain unknown. We investigated LDL contributions to the m-RCT pathway in hypercholesterolemic mice. Macrophage cholesterol efflux induced in vitro by LDL added to the culture media either alone or together with HDL or ex vivo by plasma derived from subjects with familial hypercholesterolemia was assessed. In vivo, m-RCT was evaluated in mouse models of hypercholesterolemia that were naturally deficient in CETP (cholesteryl ester transfer protein) and fed a Western-type diet. LDL induced the efflux of radiolabeled UC from cultured macrophages, and, in the simultaneous presence of HDL, a rapid transfer of the radiolabeled UC from HDL to LDL occurred. However, LDL did not exert a synergistic effect on HDL cholesterol efflux capacity in the familial hypercholesterolemia plasma. The m-RCT rates of the LDLr (LDL receptor)-KO (knockout), LDLr-KO/APOB100, and PCSK9 (proprotein convertase subtilisin/kexin type 9)-overexpressing mice were all significantly reduced relative to the wild-type mice. In contrast, m-RCT remained unchanged in HAPOB100 Tg (human APOB100 transgenic) mice with fully functional LDLr, despite increased levels of plasma APO (apolipoprotein)-B-containing lipoproteins. Hepatic LDLr plays a critical role in the flow of macrophage-derived UC to feces, while the plasma increase of APOB-containing lipoproteins is unable to stimulate m-RCT. The results indicate that, besides the major HDL-dependent m-RCT pathway via SR-BI (scavenger receptor class B type 1) to the liver, a CETP-independent m-RCT path exists, in which LDL mediates the transfer of cholesterol from macrophages to feces. Graphical Abstract: A graphical abstract is available for this article. Show less

While cholesterol content in high-density lipoproteins (HDLs) is a well-established inverse marker of cardiovascular risk, the importance of HDL-triglyceride (HDL-TG) concentration is not well known. We aim to examine plasma HDL-TG concentrations, assessed by Show less

Familial chylomicronemia syndrome (FCS) is an extremely rare lipoprotein disorder caused by mutations in at least 5 genes of the lipoprotein lipase (LPL) complex. This work shows the molecular analysis of patients diagnosed with FCS, who attended the Spanish Arteriosclerosis Society lipid units and were included in the National Dyslipidemia Registry. Among the 238 patients registered with severe hypertriglyceridemia (fasting triglycerides >1000 mg/dL), 26 were diagnosed with FCS as they had confirmed postheparin plasma LPL activity deficiency and/or homozygosity for loss-of-function mutations in LPL, GPIHBP1, APOC2, LMF1, or Apolipoprotein A5 (APOA5). Among the 26 FCS cases, 23 had mutations in the homozygous state: 19 in LPL and 4 in the GPIHBP1 gene. The molecular analysis revealed 3 novel mutations: 2 in LPL, in 2 unrelated patients (c.312delA; p.Asp105Thrfs*66 and c.629A>G; p.His210Arg), and 1 in GPHIBP1 in a third patient (c.502delC; p.Leu168Serfs*83). These 3 patients had confirmed lack of LPL activity. Three additional patients with confirmed LPL activity deficiency were heterozygous carriers of mutations in the genes analyzed. Among these, we found 2 novel mutations in APOA5 (c.50-1G>A and c.326₃₂₇insC; p.Tyr110Leufs*158). We have identified 5 novel pathogenic mutations: 2 in LPL, 1 in GPIHBP1, and 2 in the APOA5 gene. The genetic defaults accounting for the LPL activity deficiency of 23 of them have been clearly identified and 3 patients, who harbored mutations in heterozygosity, were diagnosed based on LPL activity deficiency, which raises the question of the involvement of new genes in the manifestation of FCS. Show less

Apolipoprotein A5 gene (APOA5) variability explains part of the individual's predisposition to hypertriacylglycerolaemia (HTG). Such predisposition has an inherited component (polymorphisms) and an acquired component regulated by the environment (epigenetic modifications). We hypothesize that the integrated analysis of both components will improve our capacity to estimate APOA5 contribution to HTG. We followed a recruit-by-genotype strategy to study a population composed of 44 individuals with high cardiovascular disease risk selected as being carriers of at least one APOA5 SNP (-1131T>C and/or, S19W and/or 724C>G) compared against 34 individuals wild-type (WT) for these SNPs. DNA methylation patterns of three APOA5 regions [promoter, exon 2 and CpG island (CGI) in exon 3] were evaluated using pyrosequencing technology. Carriers of APOA5 SNPs had an average of 57.5% higher circulating triacylglycerol (TG) levels (P=0.039). APOA5 promoter and exon 3 were hypermethylated whereas exon 2 was hypomethylated. Exon 3 methylation positively correlated with TG concentration (r=0.359, P=0.003) and with a lipoprotein profile associated with atherogenic dyslipidaemia. The highest TG concentrations were found in carriers of at least one SNP and with a methylation percentage in exon 3 ≥82% (P=0.009). In conclusion, CGI methylation in exon 3 of APOA5 acts, in combination with -1131T>C, S19W and 724C>G polymorphisms, in the individual's predisposition to high circulating TG levels. This serves as an example that combined analysis of SNPs and methylation applied to a larger set of genes would improve our understanding of predisposition to HTG. Show less

Triglycerides (TG) are the initiators of the metabolic changes leading to the atherogenic dyslipidemia, which is a major inducer of atherosclerosis as a result of quantitative and qualitative changes in lipoprotein subclass distributions. We hypothesized that variation at the of APOA5 gene locus, encoding apoAV, a key regulator of TG levels, significantly affect lipoprotein subclass distributions toward a more atherogenic pattern in both hyperTG patients and dyslipemic patients. We recruited four hundred and twenty-two subjects attending a Lipid Clinic, prior to lipid-lowering treatment. We genotyped two APOA5 variants, rs662799 (-1131T>C) and rs3135506 (S19W). Circulating lipoproteins were determined by nuclear magnetic resonance (NMR). Intima-media thickness (IMT) was evaluated using B-mode ultrasound. Carriers of the rare alleles of rs662799 and rs3135506 compared to common allele homozygotes, had a significantly proatherogenic profile of the VLDL and LDL subclasses, resulting in increased concentrations of the proatherogenic subclasses, large VLDLs (+133%, p<0.001) and small LDLs (+34%, p=0.014). Significant changes in smaller HDL (+71%, p=0.032), as well as an 18% decrease in large HDL (p=0.046), were also been observed. This atherogenic NMR subclass distribution was significantly associated with increased carotid IMT. The observed effects were significantly stronger in patients with a BMI≥25 kg/m2 and in male and female patients with a waist circumference≥90 cm or ≥85 cm, respectively. In a dyslipemic population, genetic variants of APOA5 modulate lipoprotein subclass distributions, inducing an atherogenic profile associated with IMT defined subclinical atherosclerosis. Show less

APOA5, a key gene regulating triglyceride (TG) levels, is reported to be expressed exclusively in the liver where it may regulate TG-rich particle synthesis and secretion. Since the same lipoprotein processing occurs in the intestine, we have postulated that this organ would also express APOA5. We have detected the APOA5 gene expression in C57BL/6J mouse and in human small intestine samples. In humans, it is expressed mainly in the duodenum and colon, with messenger RNA (mRNA) levels four orders of magnitude lower than in the liver, and the protein product being one-sixth of the liver equivalent. Subsequently, we carried out in vitro experiments in TC-7/CaCo(2) human intestinal cells to analyse the expression of APOA5, APOC3, APOB and MTP genes after the incubation with long- and short-chain fatty acids, and a peroxisome proliferator-activated receptor alpha (PPARα) agonist (Wy 14643, a fibrate therapeutic agent). In the TC-7 cell line, APOA5 expression was significantly upregulated by saturated fatty acids. The short-chain fatty acid butyrate increased APOA5 expression almost fourfold while APOB was downregulated by increasing butyrate concentrations. When TC-7 cells were incubated with PPARα agonist, the APOA5 expression was increased by 60%, while the expression of APOB, MTP and APOC3 was decreased by 50%, 30% and 45%, respectively. Our results demonstrate that APOA5 is expressed in the intestine, albeit at a much lower concentration than in the liver. While it remains to be determined whether intestinal apo A-V is functional, our in vitro experiments show that its expression is modifiable by dietary and pharmacological stimuli. Show less

Type 2 diabetic patients have an increased prevalence of hypertriglyceridemia. RBP4 has been associated with insulin resistance and hypertriglyceridemia in obesity, the metabolic syndrome and type 2 diabetes. APOA5 is proposed to be a genetic modulator of triglycerides. The aim of this study was to evaluate the relationship between RBP4 plasma levels and lipid disturbances and to determine the impact of the APOA5-1131 T>C variant on this relationship in type 2 diabetic patients. A total of 165 type 2 diabetic patients were included in the study. RBP4 plasma levels and the APOA5-1131 T>C variant were determined and the complete lipid profile was assessed by sequential ultracentrifugation. RBP4 was positively correlated with triglyceride levels in plasma and with all the components of triglyceride-rich lipoproteins. Despite the fact that a statistically significant relationship between the APOA5 genetic variant and RBP4 plasma levels was not found, the hypertriglyceridemic effect of high RBP4 levels was enhanced by the presence of the APOA5-1131 T>C genetic variant. Correlation coefficients were 2-fold higher for TC carriers compared to TT carriers with regard to RBP4 plasma levels and all the components of triglyceride-rich lipoproteins. Those type 2 diabetic patients with high RBP4 plasma concentrations and who were TC carriers showed an increased incidence of hypertriglyceridemia (OR=7.46, P=0.010). RBP4 is associated with hypertriglyceridemia in type 2 diabetic patients. The RBP4 effect is conditioned by the presence of the APOA5-1131 T>C genetic variant. Show less

Variations of the apolipoprotein A5 (APOA5) gene are strongly associated with hypertriglyceridemia. Vitamin E is transported in triglyceride (TG)-rich lipoproteins and therefore could also be modulated by apoAV. Patients with type 2 diabetes have a tendency towards high TG values and increased oxidative stress. We examined the impact of genetic APOA5 variation (-1131T-->C) on vitamin E and oxidative status in 169 non-smoker type 2 diabetic patients. Plasma samples were analyzed for lipids, lipoproteins, vitamin E, oxidized low-density lipoprotein (oxLDL), lipoperoxides, autoantibodies against oxLDL and diene formation of LDL. Vitamin E concentrations were higher in TC carriers compared with TT carriers (45.48+/-8.20 micromol/L vs. 40.32+/-10.47 micromol/L; p=0.02). The prevalence of the TC genotype was 2.6-fold higher among individuals with high vitamin E concentrations (p=0.02). The APOA5 polymorphism did not determine any differences in oxidative status. Fasting TG concentration was a significant 21% higher in carriers of the TC genotype (p=0.04) due to higher TG concentrations in very-low-density lipoprotein (VLDL) and high-density lipoprotein. The APOA5-1131T-->C polymorphism is associated with both higher vitamin E concentrations and higher VLDL-TGs in diabetic patients. Show less

The aim of this study was to investigate the effects of the apolipoprotein A5 (APOA5) 1131T>C gene variant on vitamin E status and lipid profile. The gene variant was determined in 297 healthy nonsmoking men aged 20-75 years and recruited in the VITAGE Project. Effects of the genotype on vitamin E in plasma, LDL, and buccal mucosa cells (BMC) as well as on cholesterol and triglyceride (TG) concentrations in plasma and apolipoprotein A-I (apoA-I), apoB, apoE, apoC-III, and plasma fatty acids were determined. Plasma malondialdehyde concentrations as a marker of in vivo lipid peroxidation were determined. C allele carriers showed significantly higher TG, VLDL, and LDL in plasma, higher cholesterol in VLDL and intermediate density lipoprotein, and higher plasma fatty acids. Plasma alpha-tocopherol (but not gamma-tocopherol, LDL alpha- and gamma-tocopherol, or BMC total vitamin E) was increased significantly in C allele carriers compared with homozygote T allele carriers (P = 0.02), but not after adjustment for cholesterol or TG. Plasma malondialdehyde concentrations did not differ between genotypes. In conclusion, higher plasma lipids in the TC+CC genotype are efficiently protected against lipid peroxidation by higher alpha-tocopherol concentrations. Lipid-standardized vitamin E should be used to reliably assess vitamin E status in genetic association studies. Show less

Hyperlipidemia associated with the protease inhibitor (PI) component of highly active antiretrovial treatment can lead to accelerated atherosclerosis. The apolipoprotein A-V (APOA5) gene, which affects VLDL production and lipolysis, may play a role in PI-induced hyperlipidemia, particularly in individuals with the APOA5-1131T-->C genotype. We measured lipoprotein changes in HIV-positive patients (n = 229) who had been followed for 5 years. For statistical analyses, we segregated the patients with respect to PI treatment and APOA5-1131T-->C genotype. The frequency of the C allele was 0.08, similar to that in the general population. We found a strong effect of the APOA5-1131T-->C genotype among patients receiving PIs. Carriers of the C allele had consistently increased mean (SD) triglyceride concentrations compared with noncarriers after 1 year [2.11 (1.62) vs 3.71 (4.27) mmol/L; P = 0.009], 2 years [2.48 (2.09) vs 4.02 (4.05) mmol/L, P = 0.050], 3 years [2.32 (1.71) vs 4.13 (4.26) mmol/L; P = 0.013], 4 years [2.90 (2.95) vs 5.35 (7.12) mmol/L; P was not significant], and 5 years [4.25 (5.58) vs 9.23 (9.63) mmol/L; P was not significant]. We observed the same effect on total cholesterol concentrations: after 1 year [4.93 (1.31) vs 5.87 (1.66) mmol/L; P = 0.006], 2 years [5.03 (1.12) vs 6.42 (2.48) mmol/L; P = 0.001], 3 years [5.11 (1.17) vs 6.38 (2.43) mmol/L; P = 0.009], 4 years [5.49 (1.71) vs 6.78 (3.03) mmol/L; P was not significant], and 5 years [5.56 (1.75) vs 7.90 (3.60) mmol/L; P was not significant]. HDL cholesterol showed a progressive reduction, leading to a considerably higher cholesterol/HDL cholesterol ratio after 3 years. Variability in the APOA5 gene predisposes patients with HIV, particularly those treated with PI, to severe hyperlipidemia. Show less

The newly recognised apolipoprotein (apo) AV gene (APOAV) has been linked to fasting plasma triglyceride (TG) concentrations with some polymorphisms associated with elevated fasting TGs. Since fasting plasma TGs are mainly determined by the hepatic production of TG-rich particles (very low density lipoprotein; VLDL), and fasting TGs are the major determinants of postprandial lipaemia, we have evaluated the effects of an APOAV polymorphism on postprandial triglyceridaemia, which is largely determined by the intestinal production and clearance of chylomicrons. For this purpose, diurnal capillary triglyceridaemia (reflecting postprandial lipaemia) was determined in a cohort of 88 healthy volunteers (48 males and 40 females) in relation with a -1131T>C variant in the promoter of APOAV. Thirteen of these subjects (7 males and 6 females) were carriers of the -1131C allele, which has been associated with higher fasting plasma TG levels. The carriers had higher fasting capillary TG concentrations, although plasma TGs were not significantly different from non-carriers in this cohort. Surprisingly, total diurnal triglyceridaemia calculated as the area under the capillary TG curve was similar in carriers compared to non-carriers but after correction for fasting capillary TG levels, incremental diurnal triglyceridaemia was significantly lower in carriers (1.74 (5.27) mmol/h/l) than in non-carriers (4.91 (4.90) mmol/h/l; p = 0.036). The same trends were found for both males and females when analysed separately. Since dietary intake, which is a major determinant of incremental diurnal triglyceridaemia, did not differ between the two groups, we believe that these differences are at least partly explained by the APOAV. In summary, the APOAV assessed by means of the -1131T>C variant seemed to have a paradoxical effect on postprandial lipaemia when compared to fasting TG levels. Show less

There is growing evidence of the capacity of vitamin A to regulate the expression of the genetic region that encodes apolipoproteins (apo) A-I, C-III, and A-IV. This region in turn has been proposed to modulate the expression of hyperlipidemia in the commonest genetic form of dyslipidemia, familial combined hyperlipidemia (FCHL). The hypothesis tested here was whether vitamin A (retinol), by controlling the expression of the AI-CIII-AIV gene cluster, plays a role in modulating the hyperlipidemic phenotype in FCHL. We approached the subject by studying three genetic variants of this region: a C1100-T transition in exon 3 of the apoC-III gene, a G3206-T transversion in exon 4 of the apoC-III gene, and a G-75-A substitution in the promoter region of the apoA-I gene. The association between plasma vitamin A concentrations and differences in the plasma concentrations of apolipoproteins A-I and C-III based on the different genotypes was assessed in 48 FCHL patients and 74 of their normolipidemic relatives. The results indicated that the subjects carrying genetic variants associated with increased concentrations of apoA-I and C-III (C1100-T and G-75-A) also presented increased plasma concentrations of vitamin A. This was only observed among the FCHL patients, which suggested that certain characteristics of these patients contributed to this association. The G3206-T was not associated with changes in either apolipoprotein concentrations or in vitamin A. In summary, we report a relationship between genetically determined elevations of proteins of the AI-CIII-AIV gene cluster and vitamin A in FCHL patients. More studies will be needed to confirm that vitamin A plays a role in FCHL which might also be important for its potential application to therapeutical approaches. Show less