Atherosclerosis remains the principal cause of cardiovascular morbidity and mortality worldwide, with vascular smooth muscle cells (VSMC) serving as central effectors in plaque initiation, progression, and destabilization. Although originally characterized as a hepatic regulator of LDL receptor degradation and systemic cholesterol homeostasis, PCSK9 is increasingly recognized as a pivotal mediator of vascular pathology. Within the arterial wall, VSMC constitute the predominant extrahepatic source of PCSK9, through which it exerts autocrine and paracrine effects on proliferation, migration, phenotypic plasticity, foam cell formation, oxidative stress, inflammation, and calcification. Collectively, these processes destabilize vascular homeostasis and amplify maladaptive crosstalk with endothelial and immune cells, thereby accelerating atherogenesis. Therapeutic inhibition of PCSK9 provides benefits beyond lipid lowering, reinforcing fibrous cap stability, and dampening inflammatory activity within plaques. While monoclonal antibodies and RNA-based silencing therapies are supported of a growing body of clinical data, recent advances include the development of novel oral PCSK9 inhibitors, among which MK-0616 (Enlicitide) has progressed to phase 3 evaluation. Conversely, genome editing, peptide vaccination, and CAP1-targeted biologics remain at a conceptual or early investigational stage and are still distant from regulatory approval. Yet PCSK9 lives a double life: circulating as a systemic regulator of lipids while acting locally as a driver of vascular pathology. Unraveling this duality through focused research is essential to unlock its full potential in cardiovascular medicine.

Aims Proprotein convertase subtilisin/kexin type 9 (PCSK9) is the third gene involved in autosomal dominant hypercholesterolemia, an atherosclerosis major cause. Its role in regulating plasma cholesterol through hepatocyte functions has been widely reported, and anti-PCSK9 drugs have been developed. However, direct interactions between PCSK9 and arterial pathology are not fully elucidated. As vascular smooth muscle cells (vSMC) play a major role in arterial wall pathophysiology, we describe PCSK9's presence in human atherosclerotic lesions and its interaction with vSMC. Methods Healthy and atheromatous human aortas were collected, tissues fixed, and tissue soluble release obtained after 24 h incubation in serum-free medium. Primary vSMC were isolated from aortic media. Results We showed that PCSK9, though rare in healthy tissues, was present in fibroatheromas and fatty streaks, and localized in foam cells. PCSK9 gene expression was low in the arterial wall, and no PCSK9 protein was detected in primary vSMC. However, primary vSMC could uptake PCSK9. Moreover, PCSK9 and oxidized LDL (ox-LDL) uptakes were reciprocally reduced, suggesting competition to enter vSMC. LDL receptor-related protein 1 (LRP1), a known ox-LDL receptor and potential PCSK9 receptor, had its gene expression highly expressed in primary vSMC. An LRP1-ligand antagonist significantly decreased PCSK9 uptake by vSMC. The PCSK9 monoclonal antibody reduced PCSK9 uptake by vSMC in a concentration-dependent manner. Conclusions We characterized the presence of PCSK9 in healthy and atherosclerotic human tissues and demonstrated that PCSK9 present in the aortic wall is not synthesized locally. Our results suggest that vSMC is internalizing PCSK9 through LRP1.

BACKGROUND AND AIMS:Hyperglycerolemia is a rare X-linked inborn error of metabolism whose prevalence is currently unknown. Whether extreme glycerol levels are associated with atherosclerosis is still unknown. The aim of this study was to assess subclinical atherosclerotic cardiovascular disease (ASCVD) in hyperglycerolemia. METHODS:We performed a retrospective analysis in a cohort of patients referred to a tertiary referral center for dyslipidemia between 2000 and 2011. We assessed plasma glycerol levels in all subjects exhibiting hypertriglyceridemia (defined as triglyceride levels > 200 mg/dL). Genetic testing was performed in patients with confirmed hyperglycerolemia. RESULTS:Over 314,268 lipid profiles, 11.8% had hypertriglyceridemia, of whom 13 patients had biological hyperglycerolemia. Genetic tests showed 7 previously undescribed variants of the X-linked glycerol kinase gene. None of the hyperglycerolemic patients presented carotid atherosclerosis at baseline. After a median 11.5 years follow-up, none of the hyperglycerolemic patients developed clinical ASCVD, although noninvasive coronary and carotid imaging revealed the incidence of subclinical atherosclerosis for three of the hyperglycerolemic patients with concomitant classical cardiovascular (CV) risk factors together with an unhealthy trajectory in body weight. CONCLUSIONS:Hyperglycerolemia per se is not associated with premature ASCVD. Its screening should be considered only in patients with persistent hypertriglyceridemia unresponsive to treatment. The confirmation of hyperglycerolemia can help the clinician reassure the patient concerning his CV risk, as no further assessment is required other than common CV risk factors monitoring, including body weight increase and insulin resistance that may appear over the life course.

Background and aims: PCSK9 is a key regulator of LDL-cholesterol levels. PCSK9 gain of function variants (GOFVs) cause autosomal dominant hypercholesterolemia (ADH). The first described PCSK9-GOFV, p.Ser127Arg, almost exclusively reported in France, represents 67 % of the PCSK9 French GOFVs due to a founder effect. Few other carriers are reported in South Africa and Norway. This study aims to estimate when the common ancestor lived and to describe a cohort of p.Ser127Arg carriers. Methods: Eight families and 14 p.Ser127Arg carriers were genotyped and phenotyped. Haplotypes were constructed using 11 microsatellites around PCSK9 and 6 intragenic single nucleotide polymorphisms (SNPs). To add to the biological analysis, eight additional p.Ser127Arg carriers, 12 carriers of other PCSK9-GOFVs, 93 LDLR loss of function variant (LOFV) carriers and 49 non-carriers subjects were phenotyped. Results: The most common ancestor of p.Ser127Arg was estimated to have lived 775 years ago [95 % CI: 5751075]. French Protestants exiled after the revocation of the Edict of Nantes in 1685 AD likely brought the variant to South Africa and Norway. As expected for ADH subjects, carriers of LDLR-LOFV, the p.Ser127Arg, or other PCSK9-GOFVs showed significantly higher LDL-C levels than that of the non-carriers. Interestingly, LDL-C levels are higher for LDLR-LOFVs and for the reduced secreted p.Ser127Arg than for secreted PCSK9-GOFVs, suggesting a greater effect of the p.Ser127Arg. Conversely, HDL-C was significantly lower for LDLR-LOFV and p.Ser127Arg carriers. Conclusions: This first report from a large cohort of PCSK9-p.Ser127Arg carriers provides observations suggesting a stronger hypercholesterolemic potential of the mutated pro-PCSK9 compared with the secreted mature protein. This work also provides additional data to support the association between PCSK9 and HDL metabolism, and molecular evidence that this variant appeared in France around 1248 AD (Graphical Abstract = Fig. 1).

Background and Aims: Autosomal Dominant Hypercholesterolemia (ADH) is a common monogenic disease (1/313)1 characterized by isolated elevation of LDL-cholesterol levels. ADH is associated with a high risk of cardiovascular disease due to the early development of atherosclerosis. In 80% of cases, ADH is due to variants in 4 genes (LDLR, APOB, APOE, PCSK9) and for the 20% remaining (ADH/M-) the defect has to be identified. Inhibition of genes encoding U2-spliceosome (U2-S) has been shown to decreased LDL internalization in Huh-7 cell lines2and thus suggest these genes are candidates for ADH. We aimed to investigate variants in the U2-S genes in a French ADH/M- cohort. Methods: We performed next generation sequencing (NGS) of U2-S genes in a French cohort of 219 ADH/M- patients. Selected variants present a read depth >15, a <1% frequency in GnomAD3 and are predicted deleterious according to prediction tools (CADD4>20 or MutationTaster5). Results: The sequencing highlighted 13 rare exonic variants predicted deleterious (Figure 1) and 150 in non-coding regions (131 intronic, 21 in UTRs). For the variants p.A67T in RBM25 and p.P675H in SF3A1, familial enlargement has been achieved and has shown a segregation with the ADH phenotype in each family. Conclusions: These results suggest that variants in U2-S genes are involved in ADH/M- cases. References : 1. Beheshti et al. J Am Coll Cardiol. 2020;75(20):2553-2566. 2. Zanoni et al. Circ Res. 2022;130(1):80-95. 3. https://gnomad.broadinstitute.org/ 4. https://www.mutationtaster.org/ 5. https://cadd.gs.washington.edu/snv

In the Fig. 1 of this article the VLDL receptor (VLDLR) is erroneously indicated in the liver. Numerous studies worldwide clearly demonstrated that VLDLR receptors are highly abundant in the brain, heart, kidney, lung, stomach, pancreas, muscle and adipose tissue, while barely detected in the liver [1Takahashi S. Role of VLDL receptor in atherogenesis.Curr. Opin. Lipidol. 2021; 32: 219-225https://doi.org/10.1097/MOL.0000000000000760Crossref PubMed Scopus (7) Google Scholar, 2Bhat K.G. Guleria V.S. J R.K. Rastogi G. Sharma V. Sharma A. Preliminary genome wide screening identifies new variants associated with coronary artery disease in Indian population.Am. J. Transl. Res. 2022; 14: 5124-5131PubMed Google Scholar, 3Yakovlev S. Strickland D.K. Medved L. Current view on the molecular mechanisms underlying fibrin(ogen)-dependent inflammation.Thromb. Haemostasis. 2022; 122: 1858-1868https://doi.org/10.1055/a-1910-4538Crossref PubMed Scopus (6) Google Scholar, 4Shin K.C. Huh J.Y. Ji Y. Han J.S. Han S.M. Park J. et al.VLDL-VLDLR axis facilitates brown fat thermogenesis through replenishment of lipid fuels and PPARβ/δ activation.Cell Rep. 2022; 41111806https://doi.org/10.1016/j.celrep.2022.111806Abstract Full Text Full Text PDF Scopus (3) Google Scholar, 5Krauss R.M. Lu J.T. Higgins J.J. Clary C.M. Tabibiazar R. VLDL receptor gene therapy for reducing atherogenic lipoproteins.Mol. Metabol. 2023; 69101685https://doi.org/10.1016/j.molmet.2023.101685Crossref PubMed Scopus (2) Google Scholar, 6Reddy S.S. Connor T.E. Weeber E.J. Rebeck W. Similarities and differences in structure, expression, and functions of VLDLR and ApoER2.Mol. Neurodegener. 2011; 6: 30https://doi.org/10.1186/1750-1326-6-30Crossref PubMed Scopus (56) Google Scholar, 7Fernández-Calle R. Konings S.C. Frontiñán-Rubio J. García-Revilla J. Camprubí-Ferrer L. Svensson M. et al.APOE in the bullseye of neurodegenerative diseases: impact of the APOE genotype in Alzheimer's disease pathology and brain diseases.Mol. Neurodegener. 2022; 17: 62https://doi.org/10.1186/s13024-022-00566-4Crossref PubMed Scopus (35) Google Scholar]. The authors sincerely apologize for this inaccuracy. APOE gene variants in primary dyslipidemiaAtherosclerosisVol. 328PreviewApolipoprotein E (apoE) is a major apolipoprotein involved in lipoprotein metabolism. It is a polymorphic protein and different isoforms are associated with variations in lipid and lipoprotein levels and thus cardiovascular risk. The isoform apoE4 is associated with an increase in LDL-cholesterol levels and thus a higher cardiovascular risk compared to apoE3. Whereas, apoE2 is associated with a mild decrease in LDL-cholesterol levels. In the presence of other risk factors, apoE2 homozygotes could develop type III hyperlipoproteinemia (familial dysbetalipoproteinemia or FD), an atherogenic disorder characterized by an accumulation of remnants of triglyceride-rich lipoproteins. Full-Text PDF Open Access

BACKGROUND:Autosomal dominant hypercholesterolemia (ADH) is due to deleterious variants in LDLR, APOB, or PCSK9 genes. Double heterozygote for these genes induces a more severe phenotype. More recently, a new causative variant of heterozygous ADH was identified in APOE. Here we study the phenotype of 21 adult patients, double heterozygotes for rare LDLR and rare APOE variants (LDLR+APOE) in a national wide French cohort.METHODS:LDLR, APOB, PCSK9, and APOE genes were sequenced in 5743 probands addressed for ADH genotyping. The lipid profile and occurrence of premature atherosclerotic cardiovascular diseases were compared between the LDLR+APOE carriers (n=21) and the carriers of the same LDLR causative variants alone (n=22).RESULTS:The prevalence of LDLR+APOE carriers in this French ADH cohort is 0.4%. Overall, LDL (low-density lipoprotein)-cholesterol concentrations were 23% higher in LDLR+APOE patients than in LDLR patients (9.14±2.51 versus 7.43±1.59 mmol/L, P=0.0221). When only deleterious or probably deleterious variants were considered, the LDL-cholesterol concentrations were 46% higher in LDLR+APOE carriers than in LDLR carriers (10.83±3.45 versus 7.43±1.59 mmol/L, P=0.0270). Two patients exhibited a homozygous familial hypercholesterolemia phenotype (LDL-cholesterol >13 mmol/L). Premature atherosclerotic cardiovascular disease was more common in LDLR+APOE patients than in LDLR carriers (70% versus 30%, P=0.026).CONCLUSIONS:Although an incomplete penetrance should be taken into account for APOE variant classification, these results suggest an additive effect of deleterious APOE variants on ADH phenotype highlighting the relevance of APOE sequencing.

Primary hypercholesterolemia is characterized by elevated LDL-cholesterol (LDL-C) levels isolated in autosomal dominant hypercholesterolemia (ADH) or associated with elevated triglyceride levels in familial combined hyperlipidemia (FCHL). Rare APOE variants are known in ADH and FCHL. We explored the APOE molecular spectrum in a French ADH/FCHL cohort of 5743 unrelated probands. The sequencing of LDLR, PCSK9, APOB, and APOE revealed 76 carriers of a rare APOE variant, with no mutation in LDLR, PCSK9, or APOB. Among the 31 APOE variants identified here, 15 are described in ADH, 10 in FCHL, and 6 in both probands. Five were previously reported with dyslipidemia and 26 are novel, including 12 missense, 5 synonymous, 2 intronic, and 7 variants in regulatory regions. Sixteen variants were predicted as pathogenic or likely pathogenic, and their carriers had significantly lower polygenic risk scores (wPRS) than carriers of predicted benign variants. We observed no correlation between LDL-C levels and wPRS, suggesting a major effect of APOE variants. Carriers of p.Leu167del were associated with a severe phenotype. The analysis of 11 probands suggests that carriers of an APOE variant respond better to statins than carriers of a LDLR mutation. Altogether, we show that the APOE variants account for a significant contribution to ADH and FCHL.

Autosomal Dominant Hypercholesterolemia (ADH) is a genetic disorder caused by pathogenic variants in LDLR, APOB, PCSK9 and APOE genes. We sought to identify new candidate genes responsible for the ADH phenotype in patients without pathogenic variants in the known ADH-causing genes by focusing on a French family with affected and non-affected members who presented a high ADH polygenic risk score (wPRS). Linkage analysis, whole exome and whole genome sequencing resulted in the identification of variants p.(Pro398Ala) in CYP7A1, p.(Val1382Phe) in LRP6 and p.(Ser202His) in LDLRAP1. A total of 6 other variants were identified in 6 of 160 unrelated ADH probands: p.(Ala13Val) and p.(Aps347Asn) in CYP7A1; p.(Tyr972Cys), p.(Thr1479Ile) and p.(Ser1612Phe) in LRP6; and p.(Ser202LeufsTer19) in LDLRAP1. All six probands presented a moderate wPRS. Serum analyses of carriers of the p.(Pro398Ala) variant in CYP7A1 showed no differences in the synthesis of bile acids compared to the serums of non-carriers. Functional studies of the four LRP6 mutants in HEK293T cells resulted in contradictory results excluding a major effect of each variant alone. Within the family, none of the heterozygous for only the LDLRAP1 p.(Ser202His) variant presented ADH. Altogether, each variant individually does not result in elevated LDL-C; however, the oligogenic combination of two or three variants reveals the ADH phenotype.

BACKGROUND:The role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in dyslipidemia may go beyond its immediate effects on low-density lipoprotein receptor (LDL-R) activity. OBJECTIVE:This study aimed to assess PCSK9-derived alterations of high-density lipoprotein (HDL) physiology, which bear a potential to contribute to cardiovascular risk profile. METHODS:HDL was isolated from 33 patients with familial autosomal dominant hypercholesterolemia (FH), including those carrying PCSK9 gain-of-function (GOF) genetic variants (FH-PCSK9, n = 11), together with two groups of dyslipidemic patients employed as controls and carrying genetic variants in the LDL-R not treated (ntFH-LDLR, n = 11) and treated (tFH-LDLR, n = 11) with statins, and 11 normolipidemic controls. Biological evaluations paralleled by proteomic, lipidomic and glycomic analyses were applied to characterize functional and compositional properties of HDL. RESULTS:Multiple deficiencies in the HDL function were identified in the FH-PCSK9 group relative to dyslipidemic FH-LDLR patients and normolipidemic controls, which involved reduced antioxidative, antiapoptotic, anti-thrombotic and anti-inflammatory activities. By contrast, cellular cholesterol efflux capacity of HDL was unchanged. In addition, multiple alterations of the proteomic, lipidomic and glycomic composition of HDL were found in the FH-PCSK9 group. Remarkably, HDLs from FH-PCSK9 patients were systematically enriched in several lysophospholipids as well as in A2G2S2 (GP13) glycan and apolipoprotein A-IV. Based on network analysis of functional and compositional data, a novel mosaic structure-function model of HDL biology involving FH was developed. CONCLUSION:Several metrics of anti-atherogenic HDL functionality are altered in FH-PCSK9 patients paralleled by distinct compositional alterations. These data provide a first-ever overview of the impact of GOF PCSK9 genetic variants on structure-function relationships in HDL.

We developed successive extensions of the SIR model in order to track the dynamics of the SARS-Cov2 disease. The analysis of health system available data is published in a chronicle accessible on the net: https://corona-circule.github.io/lettres/. This chronicle was initiated on late march 2020 and up to now contains 50 issues. A constant concern was the reliability of the data: for instance, we very soon evidenced that the number of confirmed cases, because of the asymptomatic carriers and the erratic testing policy, was hugely underestimated. By the end of 2020 we made a basic change in the model which consisted in accounting for a constant contagiousness time (SIR-tcc) instead of the probabilistic evolution of the end of the infection assumed so far. Recently we completed this SIR-tcc model for the vaccination effects in order to properly track the evolution of the group immunity threshold. Calculations were performed using the Excel facility (Microsoft), allowing a manual fitting of the model parameters. The results have dealt with a large number of countries, but we focus here on the data regarding France. Further pieces of information are also presented, in order to help elucidating some the factors responsible for the complex history of the pandemic dynamics. (submitted dec 14th 2021)

Four regression models have been fitted to data of the monthly number of induced abortions in Italy between January 1984 and April 1986, in order to predict the number which would have occurred in the 5 months following the Chernobyl explosion. In model I the average number of abortions per day in each month was the dependent variable and calendar months, a linear time trend and previous month's value were the independent variables. Model II included a quadratic time trend term in addition to the independent variables used in model I. Models III and IV were like models I and II except that the dependent variable was the average number of abortions per working day in each month and the effect of the previous month's value was omitted. The 4 models all implied that an excess number of abortions were performed in the 5 months following the Chernobyl accident. The mean daily excess was estimated to be 28 and 52 per day for models I and II and the mean excess per working day was estimated to be 20 and 30 by models III and IV, respectively. Clearly the estimated magnitude of the excess depends on whether the quadratic time trend is included among the explanatory variables, but these results imply that the excess is unlikely to be merely due to chance.

In adults, elevated levels of circulating Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) have been associated with increased Low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and worse cardiovascular outcomes. However, few studies analyzed the relation between PCSK9 and lipid parameters in pediatric populations. The aim of our study is to evaluate the distribution and the correlation of serum PCSK9 levels with lipid parameters in a sample of Lebanese school children. Using an immunofluorescence assay, we measured serum PCSK9 levels in 681 school children recruited from ten public and private Lebanese schools. We analyzed the association between PCSK9 and age, sex, Body Mass Index (BMI), and lipid parameters (total cholesterol (TC), LDL-C, TG, High-density lipoprotein cholesterol (HDL-C), non-HDL-C, and lipoprotein (a) (Lp(a)). Serum PCSK9 levels were significantly correlated with TC, LDL-C, and non-HDL-C (p value < 0.0001) but not with TG, HDL-C, and Lp(a). PCSK9 levels were also significantly higher in children with high TC, LDL-C, and non-HDL-C (p values = 0.0012, 0.0002, 0.001, respectively). No significant gender differences in PCSK9 were found. In addition, no significant associations between PCSK9 and both age and BMI percentiles were observed. In girls, no difference in PCSK9 values was observed according to menarche while in boys, testosterone levels were not significantly associated with PCSK9. Serum PCSK9 levels were significantly correlated with TC, LDL-C, and non-HDL-C levels. Further studies are needed to find if PCSK9 measurements have an additional value to predict future cardiovascular outcomes in pediatric populations.