Stratification in Heterozygous Familial Hypercholesterolemia: Imaging, Biomarkers, and Genetic Testing.

PURPOSE OF REVIEW: Heterozygous familial hypercholesterolemia (HeFH) is the most common monogenic autosomal dominant disorder. However, the condition is often underdiagnosed and undertreated. The objective of this review is to provide an update on the risk stratification in patients with HeFH, incorporating new cardiovascular imaging techniques, various biomarkers, and genetic studies. RECENT FINDINGS: The diagnosis of HeFH places patients in a high cardiovascular risk category due to the increased incidence of premature atherosclerotic cardiovascular disease. However, the level of risk varies significantly among different individuals with HeFH. Achieving an optimal stratification of cardiovascular risk is crucial for establishing appropriate and accurate treatment and management strategies. Different new tools such as risk scores have emerged in recent years, aiding physicians in assessing the risk stratification for HeFH using imaging, biomarkers, and genetics. This review emphasizes that not all patients with HeFH face the same cardiovascular risk. By utilizing different assessment tools, we can identify those who require more intensive monitoring, follow-up, and treatment.

Lipoproteínas ricas en triglicéridos y riesgo cardiovascular residual / Triglyceride rich lipoproteins and residual cardiovascular risk / Lipoproteínas ricas em triglicerídeos e risco cardiovascular residual / Reconocimiento a la trayectoria del Prof. Dr. Juan Miguel Castagnino†

Resumen Una vasta evidencia científica de resultados de ensayos clínicos, preclínicos, epidemiológicos y genéticos, mostraron una asociación causal entre el aumento de triglicéridos (TG), lipoproteínas ricas en TG (LRT) y sus remanentes para la enfermedad cardiovascular aterosclerótica (ECA). La acumulación de LRT circulantes puede explicar, en parte, el riesgo cardiovascular residual que se observa en pacientes eficazmente tratados para reducir sus niveles de LDL; sin embargo, persiste el riesgo de ECA. Es imprescindible que en el estudio del perfil lipídico se considere la determinación o estimación de estas lipoproteínas, sumada a la medida de TG plasmáticos. El objetivo de la presente revisión fue actualizar el conocimiento acerca de los niveles incrementados de TG, de LRT y sus remanentes, brindar alternativas para su determinación y comprender los mecanismos que involucran a las LRT en el desarrollo acelerado de la aterosclerosis. La actualización de los diferentes parámetros asociados al aumento de TG y sus valores de corte o límites de decisión clínica según la clasificación del riesgo de ECA para cada paciente, permitirá el rediseño de un informe de resultados que será de gran utilidad para el médico y el paciente con respecto a las conductas preventivas y terapéuticas de la ECA.

Abstract Vast scientific evidence from clinical, preclinical, epidemiological, and genetic trial results show a causal association between increased triglycerides (TG), TG-rich lipoproteins (TRL), and their remnants for atherosclerotic cardiovascular disease (ASCVD). The accumulation of circulating LRT may explain, in part, the residual cardiovascular risk observed in patients successfully treated to reduce their LDL levels, however, the risk of ASCVD still persists. It is essential that in the assessment of the lipid profile, the determination or estimation of these lipoproteins be considered, added to the measurement of plasmatic TG. The objective of this review is to update the knowledge about the increased levels of TG, LRT and their remnants, proprovide alternatives for their determination and understand the mechanisms that involve LRT in the accelerated development of atherosclerosis. Updating the different parameters associated with increased TG and their cut-off values or clinical decision limits according to the ASCVD risk classification for each patient will allow for the redesign of a results report that will be very useful for the physician and the patient regarding the preventive and therapeutic behaviours of the ASCVD.

Resumo Vastas evidências científicas de resultados de ensaios clínicos, pré-clínicos, epidemiológicos e genéticos mostraram uma associação causal entre o aumento de triglicerídeos (TG), lipoproteínas ricas em TG (LRT) e seus remanescentes para doença cardiovascular aterosclerótica (DCA). O acúmulo de LRT circulante pode explicar, em parte, o risco cardiovascular residual observado em pacientes tratados de maneira eficaz para reduzir seus níveis de LDL, no entanto, o risco de DCA persiste. É fundamental que no estudo do perfil lipídico seja considerada a determinação ou estimativa dessas lipoproteínas, somada à dosagem de TG plasmáticos. O objetivo desta revisão foi atualizar o conhecimento sobre os níveis aumentados de TG, LRT e seus remanescentes, fornecer alternativas para sua determinação e compreender os mecanismos que envolvem as LRT no desenvolvimento acelerado da aterosclerose. A atualização dos diferentes parâmetros associados ao aumento de TG, e seus valores de corte ou limites de decisão clínica de acordo com a classificação do risco de DCE para cada paciente, permitirá o redesenho de um relatório de resultados que será muito útil para o médico e o paciente quanto às condutas preventivas e terapêuticas da DCE.

Remnant cholesterol levels are associated with severity and death in COVID-19 patients.

Coronavirus disease-19 (COVID-19) patients with severe complications present comorbidities like cardiovascular-disease, hypertension and type-2 diabetes mellitus (DM), sharing metabolic alterations like insulin resistance (IR) and dyslipidemia. Our objective was to evaluate the association among different components of the lipid-lipoprotein profile, such as remnant lipoprotein (RLP)-cholesterol, in patients with COVID-19, and to analyze their associations with the severity of the disease and death. We studied 193 patients (68 (29-96) years; 49.7% male) hospitalized for COVID-19 and 200 controls (46 (18-79) years; 52.5% male). Lipoprotein profile, glucose and procalcitonin were assessed. Patients presented higher glucose, TG, TG/HDL-cholesterol and RLP-cholesterol levels, but lower total, LDL, HDL and no-HDL-cholesterol levels (p < 0.001). When a binary logistic regression was performed, age, non-HDL-cholesterol, and RLP-cholesterol were associated with death (p = 0.005). As the COVID-19 condition worsened, according to procalcitonin tertiles, a decrease in all the cholesterol fractions (p < 0.03) was observed with no differences in TG, while levels of RLP-cholesterol and TG/HDL-cholesterol increased (p < 0.001). Lower levels of all the cholesterol fractions were related with the presence and severity of COVID-19, except for RLP-cholesterol levels and TG/HDL-cholesterol index. These alterations indicate a lipid metabolic disorder, characteristic of IR states in COVID-19 patients. RLP-cholesterol levels predicted severity and death in these patients.

Elevated Lipoprotein(a) prevalence and association with family history of premature cardiovascular disease in general population with moderate cardiovascular risk and increased LDL cholesterol.

Background: Elevated Lipoprotein(a) [Lp(a)] is independently associated with increased cardiovascular disease (CVD) risk. There are discrepancies regarding its epidemiology due to great variability in different populations. This study aimed to evaluate the prevalence of elevated Lp(a) in people with moderate CVD risk and increased LDL-c and to determine the association between family history of premature CVD and elevated Lp(a). Methods: Random subjects from the CESCAS population-based study of people with moderate CVD risk (Framingham score 10-20 %) and LDL-c ≥ 130 mg/dL, were selected to evaluate Lp(a) by immunoturbidimetry independent of the Isoforms variability. The association between family history of premature CVD and elevated Lp(a) was evaluated using multivariate logistic regression models. Elevated Lp(a) was defined as Lp(a) ​​≥ 125 nmol/L. Results: Lp(a) was evaluated in 484 samples; men = 39.5 %, median age = 57 years (Q1-Q3: 50-63), mean CVD risk = 14.4 % (SE: 0.2), family history of premature CVD = 11.2 %, Lp(a) median of 21 nmol/L (Q1-Q3: 9-42 nmol/L), high Lp(a) = 6.1 % (95 % CI = 3.8-9.6). Association between family history of premature CVD and elevated Lp(a) in total population: OR 1.31 (95 % CI = 0.4, 4.2) p = 0.642; in subgroup of people with LDL-c ≥ 160 mg%, OR 4.24 (95 % CI = 1.2, 15.1) p = 0.026. Conclusions: In general population with moderate CVD risk and elevated LDL-c from the Southern Cone of Latin America, less than one over ten people had elevated Lp(a). Family history of premature CVD was significantly associated with the presence of elevated Lp(a) in people with LDL-c ≥ 160 mg/dL.

Phenotype of definite familial hypercholesterolemia with negative genetic study in Argentina.

Objective: Familial hypercholesterolemia (FH) is a monogenic disease, associated with variants in the LDLR, APOB and PCSK9 genes. The initial diagnosis is based on clinical criteria like the DLCN criteria. A score > 8 points qualifies the patient as "definite" for FH diagnosis. The detection of the presence of a variant in these genes allows carrying out familial cascade screening and better characterizes the patient in terms of prognosis and treatment. Methods: In the context of the FH detection program in Argentina (Da Vinci Study) 246 hypercholesterolemic patients were evaluated, 21 with DLCN score > 8 (definite diagnosis).These patients were studied with next generation sequencing to detect genetic variants, with an extended panel of 23 genes; also they were adding the large rearrangements analysis and a polygenic score of 10 SNP (single nucleotide polymorphism) related to the increase in LDL-c. Results: Of the 21 patients, 10 had variants in LDLR, 1 in APOB with APOE, 1 in LIPC plus elevated polygenic score, and 2 patients showed one deletion and one duplication in LDLR, the later with a variation in LIPA. It is highlighted that 6 of the 21 patients with a score > 8 did not show any genetic alteration. Conclusions: We can conclude that 28% of the patients with definite clinical diagnosis of FH did not show genetic alteration. The possible explanations for this result would be the presence of mutations in new genes, confusing effects of the environment over the genes, the gene-gene interactions, and finally the impossibility of detecting variants with the current available methods.

Objetivo: La hipercolesterolemia familiar (HF) es una enfermedad monogénica asociada a variantes en los genes RLDL, APOB y PCSK9. El diagnóstico inicial se basa en criterios clínicos, como el de la red de clínica de lípidos holandesa (DLCN). Un puntaje > 8 puntos califica al paciente como "definitivo" para diagnóstico de HF. La identificación de una variante en estos genes permite realizar el cribado en cascada familiar y caracterizar mejor al paciente en cuanto al pronóstico y el tratamiento. Métodos: En el marco del Programa de Detección de HF en Argentina (Estudio Da Vinci) se evaluó a 246 pacientes hipercolesterolémicos, 21 con puntaje DLCN > 8 (diagnóstico definitivo). Se estudió a estos pacientes con secuenciación de próxima generación para reconocer variantes genéticas, con un panel ampliado de 23 genes, sumado al análisis de grandes rearreglos y por último se aplicó un score poligénico de 10 SNP (polimorfismo de nucleótido único) relacionados con aumento del c-LDL. Resultados: De los 21 pacientes, 10 presentaron variantes en RLDL, uno en APOB junto a APOE, uno en LIPC más puntaje poligénico elevado, dos pacientes con una deleción y una duplicación en RLDL y este último caso con una variante en LIPA. Es destacable que 6 de los 21 pacientes con puntaje DLCN > 8 no mostraron ninguna alteración genética. Conclusiones: El 28% de los pacientes con diagnóstico clínico definitivo de HF no evidenció alteración genética. Las posibles explicaciones de este resultado serían la presencia de mutaciones en nuevos genes, los efectos confundidores del ambiente sobre los genes o la interacción gen-gen y por último la imposibilidad de detectar variantes con la metodología actual disponible.

Phenotypical, Clinical, and Molecular Aspects of Adults and Children With Homozygous Familial Hypercholesterolemia in Iberoamerica.

OBJECTIVE: Characterize homozygous familial hypercholesterolemia (HoFH) individuals from Iberoamerica. Approach and Results: In a cross-sectional retrospective evaluation 134 individuals with a HoFH phenotype, 71 adults (age 39.3±15.8 years, 38.0% males), and 63 children (age 8.8±4.0 years, 50.8% males) were studied. Genetic characterization was available in 129 (96%). The majority (91%) were true homozygotes (true HoFH, n=79, 43.0% children, 46.8% males) or compound heterozygotes (compound heterozygous familial hypercholesterolemia, n=39, 51.3% children, 46.2% males) with putative pathogenic variants in the LDLR. True HoFH due to LDLR variants had higher total (P=0.015) and LDL (low-density lipoprotein)-cholesterol (P=0.008) compared with compound heterozygous familial hypercholesterolemia. Children with true HoFH (n=34) tended to be diagnosed earlier (P=0.051) and had a greater frequency of xanthomas (P=0.016) than those with compound heterozygous familial hypercholesterolemia (n=20). Previous major cardiovascular events were present in 25 (48%) of 52 children (missing information in 2 cases), and in 43 (67%) of 64 adults with LDLR variants. Children who are true HoFH had higher frequency of major cardiovascular events (P=0.02), coronary heart (P=0.013), and aortic/supra-aortic valve diseases (P=0.022) than compound heterozygous familial hypercholesterolemia. In adults, no differences were observed in major cardiovascular events according to type of LDLR variant. From 118 subjects with LDLR variants, 76 (64%) had 2 likely pathogenic or pathogenic variants. In 89 subjects with 2 LDLR variants, those with at least one null allele were younger (P=0.003) and had a greater frequency of major cardiovascular events (P=0.038) occurring at an earlier age (P=0.001). CONCLUSIONS: There was a high frequency of cardiovascular disease even in children. Phenotype and cardiovascular complications were heterogeneous and associated with the type of molecular defect.

The antagonic behavior of GPIHBP1 between EAT and circulation does not reflect lipolytic enzymes levels in the tissue and serum from coronary patients.

BACKGROUND: Coronary artery disease (CAD) is the leading cause of morbidity and mortality worldwide. Recently, triglyceride rich lipoproteins are proposed to contribute to CAD risk; its concentrations would be partly determined by lipoprotein lipase (LPL) and endothelial lipase (EL). Epicardial adipose tissue (EAT), a visceral AT surrounding myocardium and coronary arteries, emerged as an important actor in CAD; the increase in its volume could be a consequence of LPL and EL. Circulating enzymes levels would be conditioned by local tissue factors. Our aim was to evaluate LPL, EL and their regulators levels in serum and EAT from CAD patients, searching for possible parallelisms and their role in the lipoprotein profile. METHODS: In serum, EAT and subcutaneous AT (SAT) from patients undergoing coronary artery bypass graft (CABG, n = 25) or valve replacement (No CABG, n = 25), LPL, EL and glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein-1 (GPIHBP1) expression were evaluated. Besides, Apoprotein (Apo)CII, CIII and AV were determined in serum, along with lipoprotein profile. RESULTS: Insulin-resistance markers were higher in CABG (p < 0.05). Serum LPL levels were decreased (p = 0.045), while EL levels increased (p < 0.001) in CABG, without differences in EAT or SAT. Circulating GPIHBP1 concentrations were decreased in CABG (p = 0.047), while EAT GPIHBP1 expression was increased (p < 0.001). ApoCII and ApoAV concentrations were higher in CABG (p = 0.016 and p = 0.047, respectively), without differences in ApoCIII concentrations between groups. CONCLUSIONS: In EAT, LPL and EL protein levels were not changed in CAD, although GPIHBP1 protein levels were higher. EAT would be a minor contributor to the circulating levels of the enzymes.

Phenotype of definite familial hypercholesterolemia with negative genetic study in Argentina / Fenotipo de hipercolesterolemia familiar definitivo con estudio genético negativo en Argentina

Abstract Objective: Familial hypercholesterolemia (FH) is a monogenic disease, associated with variants in the LDLR, APOB and PCSK9 genes. The initial diagnosis is based on clinical criteria like the DLCN criteria. A score > 8 points qualifies the patient as "definite" for FH diagnosis. The detection of the presence of a variant in these genes allows carrying out familial cascade screening and better characterizes the patient in terms of prognosis and treatment. Methods: In the context of the FH detection program in Argentina (Da Vinci Study) 246 hypercholesterolemic patients were evaluated, 21 with DLCN score > 8 (definite diagnosis).These patients were studied with next generation sequencing to detect genetic variants, with an extended panel of 23 genes; also they were adding the large rearrangements analysis and a polygenic score of 10 SNP (single nucleotide polymorphism) related to the increase in LDL-c. Results: Of the 21 patients, 10 had variants in LDLR, 1 in APOB with APOE, 1 in LIPC plus elevated polygenic score, and 2 patients showed one deletion and one duplication in LDLR, the later with a variation in LIPA. It is highlighted that 6 of the 21 patients with a score > 8 did not show any genetic alteration. Conclusions: We can conclude that 28% of the patients with definite clinical diagnosis of FH did not show genetic alteration. The possible explanations for this result would be the presence of mutations in new genes, confusing effects of the environment over the genes, the gene-gene interactions, and finally the impossibility of detecting variants with the current available methods.

Resumen Objetivo: La hipercolesterolemia familiar (HF) es una enfermedad monogénica asociada a variantes en los genes RLDL, APOB y PCSK9. El diagnóstico inicial se basa en criterios clínicos, como el de la red de clínica de lípidos holandesa (DLCN). Un puntaje > 8 puntos califica al paciente como "definitivo" para diagnóstico de HF. La identificación de una variante en estos genes permite realizar el cribado en cascada familiar y caracterizar mejor al paciente en cuanto al pronóstico y el tratamiento. Métodos: En el marco del Programa de Detección de HF en Argentina (Estudio Da Vinci) se evaluó a 246 pacientes hipercolesterolémicos, 21 con puntaje DLCN > 8 (diagnóstico definitivo). Se estudió a estos pacientes con secuenciación de próxima generación para reconocer variantes genéticas, con un panel ampliado de 23 genes, sumado al análisis de grandes rearreglos y por último se aplicó un score poligénico de 10 SNP (polimorfismo de nucleótido único) relacionados con aumento del c-LDL. Resultados: De los 21 pacientes, 10 presentaron variantes en RLDL, uno en APOB junto a APOE, uno en LIPC más puntaje poligénico elevado, dos pacientes con una deleción y una duplicación en RLDL y este último caso con una variante en LIPA. Es destacable que 6 de los 21 pacientes con puntaje DLCN > 8 no mostraron ninguna alteración genética. Conclusiones: El 28% de los pacientes con diagnóstico clínico definitivo de HF no evidenció alteración genética. Las posibles explicaciones de este resultado serían la presencia de mutaciones en nuevos genes, los efectos confundidores del ambiente sobre los genes o la interacción gen-gen y por último la imposibilidad de detectar variantes con la metodología actual disponible.

Fenotipo de hipercolesterolemia familiar definitivo con estudio genético negativo en Argentina.

Objective: Familial hypercholesterolemia (FH) is a monogenic disease, associated with variants in the LDLR, APOB and PCSK9 genes. The initial diagnosis is based on clinical criteria like the DLCN criteria. A score > 8 points qualifies the patient as "definite" for FH diagnosis. The detection of the presence of a variant in these genes allows carrying out familial cascade screening and better characterizes the patient in terms of prognosis and treatment. Methods: In the context of the FH detection program in Argentina (Da Vinci Study) 246 hypercholesterolemic patients were evaluated, 21 with DLCN score > 8 (definite diagnosis).These patients were studied with next generation sequencing to detect genetic variants, with an extended panel of 23 genes; also they were adding the large rearrangements analysis and a polygenic score of 10 SNP (single nucleotide polymorphism) related to the increase in LDL-c. Results: Of the 21 patients, 10 had variants in LDLR, 1 in APOB with APOE, 1 in LIPC plus elevated polygenic score, and 2 patients showed one deletion and one duplication in LDLR, the later with a variation in LIPA. It is highlighted that 6 of the 21 patients with a score > 8 did not show any genetic alteration. Conclusions: We can conclude that 28% of the patients with definite clinical diagnosis of FH did not show genetic alteration. The possible explanations for this result would be the presence of mutations in new genes, confusing effects of the environment over the genes, the gene-gene interactions, and finally the impossibility of detecting variants with the current available methods.

Objetivo: La hipercolesterolemia familiar (HF) es una enfermedad monogénica asociada a variantes en los genes RLDL, APOB y PCSK9. El diagnóstico inicial se basa en criterios clínicos, como el de la red de clínica de lípidos holandesa (DLCN). Un puntaje > 8 puntos califica al paciente como "definitivo" para diagnóstico de HF. La identificación de una variante en estos genes permite realizar el cribado en cascada familiar y caracterizar mejor al paciente en cuanto al pronóstico y el tratamiento. Métodos: En el marco del Programa de Detección de HF en Argentina (Estudio Da Vinci) se evaluó a 246 pacientes hipercolesterolémicos, 21 con puntaje DLCN > 8 (diagnóstico definitivo). Se estudió a estos pacientes con secuenciación de próxima generación para reconocer variantes genéticas, con un panel ampliado de 23 genes, sumado al análisis de grandes rearreglos y por último se aplicó un score poligénico de 10 SNP (polimorfismo de nucleótido único) relacionados con aumento del c-LDL. Resultados: De los 21 pacientes, 10 presentaron variantes en RLDL, uno en APOB junto a APOE, uno en LIPC más puntaje poligénico elevado, dos pacientes con una deleción y una duplicación en RLDL y este último caso con una variante en LIPA. Es destacable que 6 de los 21 pacientes con puntaje DLCN > 8 no mostraron ninguna alteración genética. Conclusiones: El 28% de los pacientes con diagnóstico clínico definitivo de HF no evidenció alteración genética. Las posibles explicaciones de este resultado serían la presencia de mutaciones en nuevos genes, los efectos confundidores del ambiente sobre los genes o la interacción gen-gen y por último la imposibilidad de detectar variantes con la metodología actual disponible.

Armonizacion del estudio de lipidos en el laboratorio clinico / Harmonization of the study of lipids in the clinical laboratory

Los profesionales que ejercen la bioquimica clinica son conscientes de la falta de resultados comparables entre laboratorios, independientemente de donde y cuando se realicen. Durante muchos anos el centro de la gestion de la calidad estuvo en la estandarizacion de los procedimientos de medida, la armonizacion va mas alla del metodo y los resultados analiticos e incluye todos los aspectos que hay que tener en cuenta durante el proceso total de la prueba. Los laboratorios de bioquimica clinica han logrado en las ultimas decadas importantes mejoras en la calidad de los procesos analiticos, pero es necesario un esfuerzo mayor dedicado a la vulnerabilidad de los procedimientos extra analiticos para asegurar la comparacion y la concordancia de los resultados obtenidos por diferentes laboratorios clinicos. Las iniciativas destinadas a mejorar la armonizacion de los resultados de laboratorio tienen una dimension etica y de gran importancia en el diagnostico de las dislipemias asociadas al desarrollo de aterosclerosis y la evaluacion del riesgo cardiovascular. Los estudios poblacionales aun muestran dificultades en la identificacion del mejor biomarcador que pueda evidenciar adecuadamente el riesgo cardiovascular en un individuo. La correlacion, discordancia y concordancia muestran que es necesario el diseno de un perfil de pruebas de laboratorio personalizado, con marcadores estandarizados y armonizados, que permita la prediccion del riesgo.

The health professionals who practice clinical biochemistry are aware of the lack of comparable results between laboratories, regardless of where and when they are performed. For many years, the objective of the quality management was the standardization of measurement procedures. The harmonization is beyond the methods and the analytical results, and it includes all the aspects to be taken into account during the whole process of the test. The clinical biochemistry laboratories have achieved important improvements in the quality of the analytical processes in the last decades, but greater effort is necessary for the vulnerability of the extra analytical procedures to ensure the comparison and the agreement of the results obtained by different clinical laboratories. The initiatives aimed to improve the harmonization of laboratory results have an ethical dimension and importance in the diagnosis of dyslipidemia associated with the development of atherosclerosis and the assessment of cardiovascular risk. The population studies still show difficulties in the identification of the best biomarker that can adequately show the cardiovascular risk in an individual. The correlation, discordance and concordance between biomarkers show that it is necessary to design a personalized laboratory test profile, and with standardized and harmonized markers that allow the prediction of risk.

Os profissionais que exercem a bioquímica clínica Clinical estão cientes da falta de resultados comparáveis entre laboratórios, independentemente de onde e quando forem realizados. Por muitos anos, o centro de gestão da qualidade esteve na padronização dos procedimentos de medição, a harmonização vai além do método analítico e dos resultados analíticos e inclui todos os aspectos a considerar durante o processo do teste. Laboratórios bioquímica clínica têm alcançado, nas últimas décadas grandes melhorias na qualidade dos processos analíticos, mas precisa de um esforço maior dedicado à vulnerabilidade dos procedimentos extra-analíticos, para garantir a comparação e concordancia dos resultados obtidos pelos diferentes laboratórios clínicos. Iniciativas para melhorar a harmonização dos resultados laboratoriais têm uma dimensão ética e de grande importȃncia no diagnóstico de dislipidemias associadas ao desenvolvimento de aterosclerose e à avaliação do risco cardiovascular. As pesquisas populacionais mostram ainda dificuldades em identificar o melhor biomarcador que possa demonstrar em forma adecuada o risco cardiovascular em um individuo, a correlação, discordância e concordância mostram que é necessário o desenho de um perfil de testes personalizado, com marcadores padronizados e harmonizada, que permite a previsão de risco.

Glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 and angiopoietin-like protein 4 are associated with the increase of lipoprotein lipase activity in epicardial adipose tissue from diabetic patients.

BACKGROUND AND AIMS: Epicardial adipose tissue (EAT) is a visceral AT, surrounding myocardium and coronary arteries. Its volume is higher in Type 2 diabetic (DM2) patients, associated with cardiovascular disease risk. Lipoprotein lipase (LPL) hydrolyses triglycerides (TG) from circulating lipoproteins, supplying fatty acids to AT, contributing to its expansion. We aimed to evaluate LPL expression and activity in EAT from DM2 and no DM2 patients, and its regulators ANGPTL4, GPIHBP1 and PPARγ levels, together with VLDLR expression and EAT LPL association with VLDL characteristics. METHODS: We studied patients undergoing coronary by-pass graft (CABG) divided into CABG-DM2 (n = 21) and CABG-noDM2 (n = 29), and patients without CABG (No CABG, n = 30). During surgery, EAT and subcutaneous AT (SAT) were obtained, in which LPL activity, gene and protein expression, its regulators and VLDLR protein levels were determined. Isolated circulating VLDLs were characterized. RESULTS: EAT LPL activity was higher in CABG-DM2 compared to CABG-noDM2 and No CABG (p=0.002 and p<0.001) and in CABG-noDM2 compared to No CABG (p=0.02), without differences in its expression. ANGPTL4 levels were higher in EAT from No CABG compared to CABG-DM2 and CABG-noDM2 (p<0.001). GPIHBP1 levels were higher in EAT from CABG-DM2 and CABG-noDM2 compared to No CABG (p= 0.04). EAT from CABG-DM2 presented higher PPARγ levels than CABG-noDM2 and No CABG (p=0.02 and p=0.03). No differences were observed in VLDL composition between groups, although EAT LPL activity was inversely associated with VLDL-TG and TG/protein index (p<0.05). CONCLUSIONS: EAT LPL regulation would be mainly post-translational. The higher LPL activity in DM2 could be partly responsible for the increase in EAT volume.

Fetal and postnatal zinc restriction: Sex differences in metabolic alterations in adult rats.

OBJECTIVE: Intrauterine and postnatal micronutrient malnutrition may program metabolic diseases in adulthood. We examined whether moderate zinc restriction in male and female rats throughout fetal life, lactation, or postweaning growth induces alterations in liver, adipose tissue, and intermediate metabolism. METHODS: Female Wistar rats were fed low-zinc or control zinc diets from pregnancy to offspring weaning. After weaning, male and female offspring were fed either a low-zinc or a control zinc diet. At 74 d of life, oral glucose tolerance tests were performed and serum metabolic profiles were evaluated. Systolic blood pressure and oxidative stress and morphology of liver and retroperitoneal adipose tissue were evaluated in 81 d old offspring. RESULTS: Zinc restriction during prenatal and postnatal life induced an increase in systolic blood pressure, hyperglycemia, hypertriglyceridemia, higher serum glucose levels at 180 min after glucose overload, and greater insulin resistance indexes in male rats. Hepatic histologic studies revealed no morphologic alterations, but an increase in lipid peroxidation and catalase activity were identified in zinc-deficient male rats. Adipose tissue from zinc-deficient male rats had adipocyte hypertrophy, an increase in lipid peroxidation, and a reduction in catalase and glutathione peroxidase activity. Adequate dietary zinc content during postweaning growth reversed basal hyperglycemia, hypertriglyceridemia, insulin resistance indexes, hepatic oxidative stress, and adipocyte hypertrophy. Female rats were less sensitive to the metabolic effects of zinc restriction. CONCLUSIONS: This study strengthens the importance of a balanced intake of zinc during growth to ensure adequate lipid and carbohydrate metabolism in adult life.

Endothelial Lipase Is an Alternative Pathway for Fatty Acid Release from Lipoproteins: Evidence from a High Fat Diet Model of Obesity in Rats.

Lipoprotein lipase (LPL) and endothelial lipase (EL) are involved in lipoprotein metabolism. In insulin-resistance, their behavior is altered. Peroxisome proliferator-activated receptors (PPAR) and apoproteins (apo)CII and CIII could be partly responsible for these alterations. To evaluate this response, we assessed Lpl and Lipg expression, protein levels, and enzyme activity in adipose tissue (AT) and heart in an obesity model. Besides, we assessed the role of PPAR and apoC. Male Wistar rats were fed with standard diet (Control, n = 14) or high-fat diet (HFD, n = 14) for 14 weeks. Glucose and lipoprotein profiles were measured. Histological studies were performed in heart and epididymal AT. Lpl and Lipg were assessed by reverse transcription polymerase chain reaction (RT-qPCR), protein levels by Western Blot, and activities by radiometric assays. Cardiac and AT PPAR expression were measured by Western Blot and hepatic Apoc2 and Apoc3 mRNA by RT-qPCR. In HFD, fat deposits were observed in hearts, whereas AT presented a higher adipocyte size. In heart and AT, no differences were found in Lipg mRNA between groups, while AT Lpl mRNA and LPL protein were decreased in HFD, without differences in heart. In both tissues, EL protein levels and activity were increased and inversely associated with decreased LPL activity, being partially responsible for the atherogenic lipoprotein profile in HFD. PPARγ expression in AT was decreased in HFD, without differences in cardiac PPARδ expression and hepatic apoC mRNA. The increase in EL activity could be an alternative pathway for fatty acid release from lipoproteins and uptake in tissues with decreased LPL activity. In AT, PPARγ could be involved in enzyme regulation.

Unusual genetic variants associated with hypercholesterolemia in Argentina.

BACKGROUND AND AIMS: Marked hypercholesterolemia, defined as low density lipoprotein cholesterol (LDL-C) levels ≥ 190 mg/dL, may be due to LDLR, APOB, and PCSK9 variants. In a recent analysis, only 1.7% of cases had such variants. Our goal was to identify other potential genetic causes of hypercholesterolemia. METHODS: In a total of 51,253 subjects with lipid testing, 3.8% had elevated total cholesterol >300 mg/dL and/or LDL-C≥190 mg/dL. Of these, 246 were further studied, and 69 without kidney, liver, or thyroid disease and who met Dutch Lipid Clinic Network criteria of ≥6 points had DNA sequencing done at the LDLR, APOB, PCSK9, APOE, LDLRAP1, STAP1, ABCG5, ABCG8, CYP27A1, LIPA, LIPC, LIPG, LPL, and SCARB1 gene loci and also had 10 SNP analysis for a weighted high LDL-C genetic risk score. RESULTS: In the 69 subjects with genetic analyses, the following variants were observed in 37 subjects (53.6%): LDLR (n = 20, 2 novel), ABCG5/8 (n = 7, 2 novel), APOB (n = 3, 1 novel), CYP27A1 (n = 3, 1 novel), LIPA (n = 2, 1 novel), APOE (n = 2), LIPC (n = 1, novel), LIPG (n = 1, novel), and SCARB1 (n = 1); 14 subjects (20.3%) had a high polygenic score, with 4 (5.8%) having no variants. CONCLUSIONS: Our data indicate that in addition to variants in LDLR, APOB, PCSK9, APOE, LDLRAP1, and STAP1, variants in ABCG5/8, CYP27A1, LIPA, LIPC, and LIPG may be associated with hypercholesterolemia and such information should be used to optimize therapy.

Metalloproteinases in non-alcoholic fatty liver disease and their behavior in liver fibrosis.

Non-alcoholic fatty liver disease (NAFLD) is a clinical entity of high prevalence in the world characterized by fatty infiltration of liver tissue in the absence of alcohol consumption. The natural history of the disease develops in successive phases reflected in different histological stages, with 10-20% of patients developing liver cirrhosis and fibrosis. Fibrosis is a basic connective tissue lesion defined by the increase of the fibrillary extracellular matrix (ECM) components in a tissue or organ. Matrix metalloproteinases (MMPs) constitute a family of endopeptidases, which are involved in ECM and basement membranes components degradation. Fibrogenic process is characterized by altered ECM composition, associated with modifications in MMPs behavior. The active cross-talk between adipose tissue and liver can be altered in pathologies associated to insulin resistance (IR), such as NAFLD. The role of adipokines on MMPs behavior in the liver could be partly responsible of liver damage during IR. The aim of this revision is to describe the behavior of MMPs in NAFLD and its role in the associated fibrosis.

Vitamin D is Related to Markers of Vulnerable Plaque in Acute Myocardial Infarction.

BACKGROUND: Vitamin D is a fat soluble vitamin involved in calcium and bone metabolism; recently its deficiency has been related to cardiovascular disease. In cardiac tissue, vitamin D suppresses metalloproteinases (MMPs) expression, enzymes directly associated with vulnerable plaque. OBJECTIVE: To investigate whether the association between vitamin D and leptin is related to markers of vulnerable plaque, such as MMPs in patients with acute myocardial infarction. METHODS: We studied 66 male patients with acute myocardial infarction, undergoing primary angioplasty. Blood samples were obtained at admission and 24hs after the surgery. Leptin and vitamin D concentrations in serum and MMP-2 and -9 activities in plasma were determined. RESULTS: MMP-2 activity was increased in Vitamin D deficient/insufficient patients at admission (p=0.04) and 24 hs later (p=0.05). In a linear regression model, vitamin D explained 24% of the variance of MMP-2 activity (F=2.839 p=0.04). At admission, vitamin D correlated with serum leptin (r=-0.302 p=0.033), and explained 39.5% of its variation (F=4.432 p=0.003). CONCLUSION: In the studied population, vitamin D was inversely related to MMP-2 and leptin which are involved in coronary artery disease and acute myocardial infarction. The decrease in this hormone levels would be associated with a worse metabolic profile in acute coronary syndrome patients.

Preliminary spectrum of genetic variants in familial hypercholesterolemia in Argentina.

BACKGROUND: Familial hypercholesterolemia (FH) is a genetic disorder characterized by elevated low-density lipoprotein cholesterol and early cardiovascular disease. As cardiovascular disease is a leading cause of mortality in Argentina, early identification of patients with FH is of great public health importance. OBJECTIVE: The aim of our study was to identify families with FH and to approximate to the characterization of the genetic spectrum mutations of FH in Argentina. METHODS: Thirty-three not related index cases were selected with clinical diagnosis of FH. Genetic analysis was performed by sequencing, multiplex ligation-dependent probe amplification, and bioinformatics tools. RESULTS: Twenty genetic variants were identified among 24 cases (73%), 95% on the low-density lipoprotein receptor gene. The only variant on APOB was the R3527Q. Four were novel variants: c.-135C>A, c.170A>C p.(Asp57Ala), c.684G>C p.(Glu228Asp), and c.1895A>T p.(Asn632Ile); the bioinformatics' analysis revealed clear destabilizing effects for 2 of them. The exon 14 presented the highest number of variants (32%). Four variants were observed in more than 1 case and the c.2043C>A p.(Cys681*) was carried by 18% of index cases. Two true homozygotes, 3 compound heterozygotes, and 1 double heterozygote were identified. CONCLUSION: This study characterizes for the first time in Argentina genetic variants associated with FH and suggest that the allelic heterogeneity of the FH in the country could have 1 relative common low-density lipoprotein receptor mutation. This knowledge is important for the genotype-phenotype correlation and for optimizing both cholesterol-lowering therapies and mutational analysis protocols. In addition, these data contribute to the understanding of the molecular basis of FH in Argentina.

Clinical and molecular aspects of familial hypercholesterolemia in Ibero-American countries.

BACKGROUND: There is little information about familial hypercholesterolemia (FH) epidemiology and care in Ibero-American countries. The Ibero-American FH network aims at reducing the gap on diagnosis and treatment of this disease in the region. OBJECTIVE: To describe clinical, molecular, and organizational characteristics of FH diagnosis in Argentina, Brazil, Chile, Colombia, Mexico, Portugal, Spain, and Uruguay. METHODS: Descriptive analysis of country data related to FH cascade screening, molecular diagnosis, clinical practice guidelines, and patient organization presence in Ibero-America. RESULTS: From a conservative estimation of an FH prevalence of 1 of 500 individuals, there should be 1.2 million heterozygous FH individuals in Ibero-America and roughly 27,400 were diagnosed so far. Only Spain, Brazil, Portugal, and Uruguay have active cascade screening programs. The prevalence of cardiovascular disease ranged from 10% to 42% in member countries, and the highest molecular identification rates are seen in Spain, 8.3%, followed by Portugal, 3.8%, and Uruguay with 2.5%. In the 3 countries with more FH patients identified (Spain, Portugal, and Brazil) between 10 and 15 mutations are responsible for 30% to 47% of all FH cases. Spain and Portugal share 5 of the 10 most common mutations (4 in low density lipoprotein receptor [LDLR] and the APOB3527). Spain and Spanish-speaking Latin American countries share 6 of the most common LDLR mutations and the APOB3527. LDL apheresis is available only in Spain and Portugal and not all countries have specific FH diagnostic and treatment guidelines as well as patient organizations. CONCLUSIONS: Ibero-American countries share similar mutations and gaps in FH care.

Adiponectina determinaría el predominio de VLDL alteradas en el síndrome metabólico / Adiponectin would determine the predominance of altered VLDL in metabolic syndrome / Adiponectina iria determinar o predomínio de VLDL alteradas na síndrome metabólica

El objetivo del trabajo fue evaluar si la reducción de adiponectina (ADP) en el síndrome metabólico (SMet), influencia las características aterogénicas de VLDL. Se estudiaron 45 pacientes con SMet y 15 controles sanos. En suero en ayunas se midió perfil lipídico, ácidos grasos libres (AGL), ADP, se aisló VLDL (d<1,006 g/L) caracterizándola en su composición química y tamaño (HPLC-exclusión molecular). En plasma post-heparínico se determinó la actividad de lipoproteína lipasa (LPL). En SMet VLDL mostró incremento de masa, número de partículas, contenido en triglicéridos-VLDL y mayor proporción de VLDL grandes (p<0,05). El incremento de AGL correlacionó con la masa de VLDL (r=0,36; p=0,009), número de partículas-VLDL (r=0,45; p=0,0006) y %-VLDL grandes (r=0,32; p=0,02). SMet mostró descenso en ADP (7,4±4,8 vs. 15,5±7,2 μg/mL, p=0,01) y en actividad de LPL (p=0,01), que correlacionaron entre si (r=0,38; p=0,01; ajustado por HOMA-IR y cintura: β=0,35; p=0,02). ADP correlacionó negativamente con AGL y %-VLDL grandes (p<0,03). Se concluye que en SMet la disminución de ADP favorecería la secreción de VLDL sobre-enriquecidas en triglicéridos y de mayor tamaño, y además retardaría el catabolismo de VLDL mediado por LPL, resultando en la acumulación de VLDL alteradas en circulación con características aterogénicas.

The aim of the work was to evaluate whether the reduction of adiponectin (ADP) in metabolic syndrome (MetS) affects the atherogenic features of VLDL. A total of 45 patients with MetS (ATPIII) and 15 healthy controls were studied. In fasting serum, lipid profile, free fatty acids (FFA) and ADP were determined. VLDL was isolated (d<1.006 g/L) and characterized in chemical composition and size (size exclusion-HPLC). In post-heparin plasma, lipoprotein lipase (LPL) activity was measured. In MetS, VLDL showed increased total mass, particle number, VLDL-triglyceride content and higher large-VLDL proportion (p<0.05). The increase in FFA correlated with VLDL mass (r=0.36; p=0.009), VLDL particle number (r=0.45; p=0.0006) and large-VLDL proportion (r=0.32; p=0.02). MetS patients showed a decrease in ADP (7.4±4.8 vs. 15.5±7.2 μg/mL, p=0.01) and in LPL activity (p=0.01), that positively correlated between them (r=0.38; p=0.01; adjusted by HOMA-IR and waist: β=0.35; p=0.02). ADP inversely correlated with FFA and large-VLDL% (p<0.03). It can be concluded that in MetS, decreased ADP would favour the secretion of triglyceride over-enriched and larger VLDL particles, and also would delay VLDL catabolism mediated by LPL, resulting in the accumulation of altered VLDL with atherogenic characteristics.

O objetivo do trabalho foi avaliar se a redução da adiponectina (ADP) na síndrome metabólica (SM), afeta as características aterogênicas das VLDL. Foram estudados 45 indivíduos com SM e 15 controles saudáveis. Em jejum, foi medido em soro o perfil lipídico, ácidos graxos livres (AGL) e ADP. Foram isoladas as VLDL (d <1,006 g / L) caracterizando-as em relação a sua composição química e tamanho (HPLC- exclusão molecular). No plasma pós-heparina foi medida a atividade da lipoproteína lipase (LPL). Em indivíduos com SM, as VLDL apresentaram aumento de massa, número de partículas, conteúdo de triglicerídeos -VLDL e maior proporção de VLDL grandes (p<0,05). O aumento de AGL correlacionou com a massa de VLDL (r=0,36; p=0,009), número de partículas -VLDL (r=0,45; p=0,0006) e percentual -VLDL grandes (r=0,32; p=0,02). A SM mostrou uma diminuição em ADP (7,4±4,8 vs. 15,5±7,2 μg/mL, p=0,01) e em atividade de LPL (p=0,01), que correlacionaram entre eles (r=0,38; p=0,01; ajustada por HOMA-IR e cintura: β=0,35; p=0,02). A ADP correlacionou em forma negativa com AGL e %-VLDL grandes (p<0,03). A conclusão é que em indivíduos com SM, a diminuição da ADP iria favorecer a secreção de VLDL super-enriquecidas em triglicerídeos e de maior tamanho, e também atrasaria o catabolismo das VLDL mediado por LPL, resultando na acumulação de VLDL alteradas em circulação com características aterogênicas.

Atherogenic Lipoproteins in Subclinical Hypothyroidism and Their Relationship with Hepatic Lipase Activity: Response to Replacement Treatment with Levothyroxine.

BACKGROUND: Qualitative lipoprotein changes, such as an increase in fasting remnants, are reported in subclinical hypothyroidism (SCH). It was hypothesized that such changes are due to reduced hepatic lipase (HL) activity in SCH: HL is an enzyme regulated by thyroid hormones, and is involved in the degradation of triglyceride (TG)-rich remnants. This study aimed to quantify remnant-like lipoproteins (RLP), small dense LDL (sdLDL), and HL activity in women with SCH, and to assess these parameters after levothyroxine replacement therapy. METHODS: This was an observational cross-sectional study with a subsequent longitudinal follow-up. Findings in women with thyrotropin levels >4.5 mIU/L (SH group) were compared with age- and body mass index (BMI)-matched euthyroid women (control group). In addition, a subgroup analysis was undertaken in SCH women who chose to receive levothyroxine treatment (0.9 µg/kg/day) for 6 months. RLP was quantified by measuring cholesterol (RLP-C) and triglycerides (RLP-TG) after immunoaffinity chromatography, and sdLDL by automated standardized methods; HL activity was measured in post-heparin plasma. RESULTS: The SCH group included 37 women; 29 women were included in the control group. In addition, 22 women with SCH were included in the subgroup analysis (levothyroxine treatment). Significantly higher RLP values were observed in the SCH group than in the control group: RLP-C (median [range], mg/dL): 20.3 (5.8-66.8) versus 10.2 (2.7-36.3), p = 0.005; RLP-TG (mg/dL): 26.3 (3.2-123.3) versus 12.1 (2.5-61.6), p = 0.033. HL activity (mean ± standard deviation [SD], µmol free fatty acid/mL post-heparin plasma.h)-9.83 ± 4.25 versus 9.92 ± 5.20, p = 0.707-and sdLDL levels (mg/dL)-23.1 ± 10.7 versus 22.6 ± 8.4, p = 0.83-were similar. After levothyroxine, RLP-C decreased-21.5 (5.8-66.8) versus 17.2 (4.1-45.6), p = 0.023-and HL increased-9.75 ± 4.04 versus 11.86 ± 4.58, p = 0.012-in the subgroup of SCH women. No changes in sdLDL were observed. CONCLUSIONS: Women with SCH have higher RLP levels than matched controls do, but their RLP-C levels decrease significantly following levothyroxine therapy. Furthermore, HL activity also increases after levothyroxine therapy and can be interpreted as a possible explanation for the decrease in RLP-C.