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.

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.

APOE -491 T allele may reduce the risk of atherosclerotic lesions among middle-aged women.

Genetic variability of the APOE gene confers susceptibility to coronary artery disease (CAD). Beyond variability on the coding region, polymorphisms in the regulatory region of the APOE gene have been associated with variation on plasma cholesterol levels. It has also been demonstrated a complex and multifactorial association between, APOE gene polymorphisms, gender, plasma lipids levels and risk of CAD. In the present case-control study, we examined polymorphisms -427 T/C and -491 A/T in the promoter region of APOE in relation to lipid profile and the coronary atherosclerosis, in a sample of Argentinean adults with (cases) and without (controls) atherosclerotic injuries regarding gender and age. In females below 60 years APOE -491 T allele was less prevalent in cases than in controls (OR 0.12, 95% CI 0.04-0.76). Among females cases the T allele was more frequent with increasing age (OR 0.49, 95% CI 0.27-0.90). Female up to 45 years who were carriers of the T allele showed lower levels of total (P = 0.01) and LDL cholesterol (P = 0.02) compared with non-carriers. Levels of total and LDL cholesterol increased with the age only in female carriers (P < 0.01 and P < 0.01). No differences were observed for HDL and TG levels. Allele C of polymorphism APOE -427 was associated with higher levels of triglycerides (P < 0.01). We conclude that, in middle-aged women, APOE -491 T allele contributes keeping lower levels of LDL cholesterol in the population studied, and would have a putative protective effect for the development of CAD.

[Atherogenic lipoprotein remnants in humans]. / Lipoproteínas remanentes aterogénicas en humanos.

Remnant lipoproteins (RLPs) are the lipolytic product of triglycerides transported by very low density lipoproteins (VLDL) of hepatic and intestinal origin and intestinal chylomicrons. Lipoprotein lipase activity hydrolyse triglycerides in several steps, producing heterogeneous particles. Fasting plasma concentration in normolipidemic subjects is low, but it increases in post-prandial states. Genetic alterations in Apo-E subtypes increases RLPs plasma concentration and produce dyslipoproteinemia phenotype. RLPs atherogenicity depends on their role as endothelial injuring factors, their impaired recognition by lipoprotein receptors, and their susceptibility to oxidative stress. They also promote the circulation of molecular adhesion molecules, the internalization in subendothelial macrophages via scavenger receptors and the accumulation in foam cells, all of them early mechanisms of atheromatosis. RLPs metabolism has been a subject of controversial studies. Their origin from different lipoproteins may explain their structural heterogeneity, therefore increasing the methodological difficulties to include RLPs in the atherogenic lipoprotein profile in the epidemiological studies of the field. Last advances on metabolism of RLPs and their emergent clinical role justifies an up dated revision of RLPs.

Lipoproteínas remanentes aterogénicas en humanos / Atherogenic lipoprotein remnants in humans

La lipoproteínas remanentes (RLPs) son el producto de la lipólisis de los triglicéridos transportados por las lipoproteínas de baja densidad (VLDL) de origen hepático e intestinal y de los quilomicrones intestinales. Dicha lipólisis es catalizada por la lipoproteína lipasa y se produce en pasos sucesivos, de manera que los productos son heterogéneos. Su concentración plasmática en ayunas es pequeña en pacientes normolipémicos y aumenta en el estado post-prandial. Las alteraciones genéticas en subtipos de su componente Apo-E aumentan notablemente su concentración plasmática y producen el fenotipo de disbetalipoproteinemia. Se las considera aterogénicas porque injurian el endotelio, sufren estrés oxidativo, son captadas por los macrófagos en el subendotelio vascular y generan las células espumosas que son precursoras de ateromas. Su origen metabólico, como productos de varios tipos de lipoproteínas, explican su estructura heterogénea, sus concentraciones plasmáticas variables y las dificultades metodológicas que dificultan su inclusión en el perfil lipoproteico como parte de los estudios epidemiológicos. Los últimos avances en los estudios metabólicos y la actualización de su papel clínico, justifican una revisión de los conocimientos actuales.

Remnant lipoproteins (RLPs) are the lipolytic product of triglycerides transported by very low density lipoproteins (VLDL) of hepatic and intestinal origin and intestinal chylomicrons. Lipoprotein lipase activity hydrolyse triglycerides in several steps, producing heterogeneous particles. Fasting plasma concentration in normolipidemic subjects is low, but it increases in post-prandial states. Genetic alterations in Apo-E subtypes increases RLPs plasma concentration and produce dyslipoproteinemia phenotype. RLPs atherogenicity depends on their role as endothelial injuring factors, their impaired recognition by lipoprotein receptors, and their susceptibility to oxidative stress. They also promote the circulation of molecular adhesion molecules, the internalization in subendothelial macrophages via scavenger receptors and the accumulation in foam cells, all of them early mechanisms of atheromatosis. RLPs metabolism has been a subject of controversial studies. Their origin from different lipoproteins may explain their structural heterogeneity, therefore increasing the methodological difficulties to include RLPs in the atherogenic lipoprotein profile in the epidemiological studies of the field. Last advances on metabolism of RLPs and their emergent clinical role justifies an up dated revision of RLPs.

Common mitochondrial DNA deletion associated with sudden natural death in adults.

One of the most frequent causes of death in developed countries is sudden natural death (SND), which is the most common indication for medico-legal autopsies. Cardiac diseases are frequently detected among SND. Mitochondrial DNA (mtDNA) is easily damaged by reactive oxygen species, and it may cause dysfunction in tissues, leading to early events in cardiovascular disease. A specific mtDNA deletion of 4977 bp is associated to aging, myocardial dysfunction, and bioenergetic deficit. The potential link between mtDNA damage and SND has not been investigated before. Our aim was to evaluate the accumulation of the common mtDNA4977-deletion in cardiac muscle samples from autopsies of SND in adults (n = 14) in comparison to control samples from unnatural deaths (n = 12). Serial dilution-polymerase chain reaction method was performed to estimate the proportion of the total mtDNA harboring the mtDNA4977-deletion. Coefficient variation intra-assay was 8%, and inter-assay was 12%. MtDNA4977-deletion percentage was higher in samples obtained from victims of SND than in those from subjects who died of unnatural causes (p < 0.05). No differences in mtDNA4977-deletion were found between SND victims 39-51 years old, and no correlation was found between these samples and age, r = 0.30, p = 0.29 while it was significant among control samples, r = 0.68, p < 0.05. The association between mtDNA4977 deletion with SND victims might offer a tool to provide additional information to clarify complex SND investigations.

Nitric oxide inhibits prooxidant actions of uric acid during copper-mediated LDL oxidation.

Interactions between uric acid and physiologically relevant fluxes of nitric oxide ((?)NO) during copper-mediated low-density lipoprotein (LDL) oxidation were evaluated. In the absence of (?)NO, a dual pro- and antioxidant action of uric acid was evident: low concentrations of uric acid enhanced lipid oxidation and alpha-tocopherol consumption, while its protective role was observed at higher concentrations. The prooxidant effects of uric acid were mostly related to its copper-reducing ability to form Cu(+), an initiator of lipid oxidation processes. While the prooxidant action of uric acid was completely inhibited by (?)NO, the antioxidant action of (?)NO was slightly counterbalanced by uric acid. Enhancement of alpha-tocopherol consumption by uric acid was inhibited in the presence of (?)NO while additive antioxidant effects between (?)NO and uric acid were observed in conditions where uric acid spared alpha-tocopherol. Altogether, these results suggest that in the artery wall, the (?)NO/uric acid pair may exert antioxidant actions on LDL, even if increased amounts of redox active copper were available at conditions favoring prooxidant activities of uric acid.

Aterosclerosis: modificaciones cualitativas en lipoproteínas aterogénicas y protectoras / Atherosclerosis: qualitative modifications in atherogenic and protective lipoproteins

El objetivo de este trabajo es evaluar las alteraciones cuali y cuantitativas de las lipoproteínas plasmáticas en pacientes con enfermedad cardiovascular y en grupos de pacientes cuyo riesgo aterogénico está aumentado, como los que padecen diabetes de tipo II o las mujeres postmenopáusicas. La aterosclerosis está caracterizada como un síndrome multicausal, pero las tendencias modernas adjudican un papel importante a la relación entre el endotelio vascular y las lipoproteínas plasmáticas. Alteraciones cualitativas de las lipoproteínas que afectan su composición lipídica y apoproteica, el nuevo concepto de subespecies de lipoproteínas y la injuria sobre el endotelio que facilita su filtración y la deposición de sus componentes en la pared arterial, son fenómenos interrelacionados. También el transporte del colesterol desde las membranas hacia sus sitios catabólicos depende del tipo de subespecie de HDL que interviene en el proceso. En esta serie de estudios se tratan tres aspectos que involucran a las lipoproteínas plasmáticas típicas, modificados o con alteraciones en su composición, en pacientes con enfermedad cardiovascular aterosclerótica, diabéticos de tipo II y mujeres postmenopáusicas. Capítulo I: las alteraciones cualitativas de LDL pueden conducir a la oxidación de sus componentes que favorecen su ingreso a los macrófagos, transformándolos así en células espumosas. Dado que las LDL oxidadas son rápidamente captadas por los receptores scavenger, su suceptibilidad a la oxidación in vitro es una característica que permite predecir el deterioro metabólico y su aterogenicidad. Se estudiaron 50 pacientes con enfermedad cardiovascular aterosclerótica, 25 normolipémicos de acuerdo con criterios clásicos y 25 dislipémicos comparados con 39 controles sanos. Se separó LDL por ultracentrifugación secuencial y se estudio su composición química. Se midió el contenido en malondialdehído en condiciones basales y a los 120 min. post-oxidación con Cu2+. Se analizó la electronegatividad de LDL oxidada y la producción de dienos conjugados que evalúa la resistencia a la oxidación por según el tiempo lag, que mide el tiempo que tarda en dispararse la etapa de propagación de la lipoperoxidación. La LDL de pacientes presentó mayor contenido de triglicéridos e índice apo B/colesterol, definiendo partículas más oxidables... (TRUNCADO)(AU)

Aterosclerosis: modificaciones cualitativas en lipoproteínas aterogénicas y protectoras / Atherosclerosis: qualitative modifications in atherogenic and protective lipoproteins

El objetivo de este trabajo es evaluar las alteraciones cuali y cuantitativas de las lipoproteínas plasmáticas en pacientes con enfermedad cardiovascular y en grupos de pacientes cuyo riesgo aterogénico está aumentado, como los que padecen diabetes de tipo II o las mujeres postmenopáusicas. La aterosclerosis está caracterizada como un síndrome multicausal, pero las tendencias modernas adjudican un papel importante a la relación entre el endotelio vascular y las lipoproteínas plasmáticas. Alteraciones cualitativas de las lipoproteínas que afectan su composición lipídica y apoproteica, el nuevo concepto de subespecies de lipoproteínas y la injuria sobre el endotelio que facilita su filtración y la deposición de sus componentes en la pared arterial, son fenómenos interrelacionados. También el transporte del colesterol desde las membranas hacia sus sitios catabólicos depende del tipo de subespecie de HDL que interviene en el proceso. En esta serie de estudios se tratan tres aspectos que involucran a las lipoproteínas plasmáticas típicas, modificados o con alteraciones en su composición, en pacientes con enfermedad cardiovascular aterosclerótica, diabéticos de tipo II y mujeres postmenopáusicas. Capítulo I: las alteraciones cualitativas de LDL pueden conducir a la oxidación de sus componentes que favorecen su ingreso a los macrófagos, transformándolos así en células espumosas. Dado que las LDL oxidadas son rápidamente captadas por los receptores scavenger, su suceptibilidad a la oxidación in vitro es una característica que permite predecir el deterioro metabólico y su aterogenicidad. Se estudiaron 50 pacientes con enfermedad cardiovascular aterosclerótica, 25 normolipémicos de acuerdo con criterios clásicos y 25 dislipémicos comparados con 39 controles sanos. Se separó LDL por ultracentrifugación secuencial y se estudio su composición química. Se midió el contenido en malondialdehído en condiciones basales y a los 120 min. post-oxidación con Cu2+. Se analizó la electronegatividad de LDL oxidada y la producción de dienos conjugados que evalúa la resistencia a la oxidación por según el tiempo lag, que mide el tiempo que tarda en dispararse la etapa de propagación de la lipoperoxidación. La LDL de pacientes presentó mayor contenido de triglicéridos e índice apo B/colesterol, definiendo partículas más oxidables... (TRUNCADO)

Lipoproteína de baja densidad rica en triglicéridos y actividad de lipasa hepática en pacientes diabéticos insulino-dependientes / Low density lipoprotein rich in triglycerides and hepatic lipose activity in insulin-dependent diabetic patients

Genetic hepatic lipase (HL) deficiency is associated with low density lipoprotein (LDL) rich in triglycerides (TG), whose affinity for B:E receptors is decreased. In rats, experimental hypoinsulinemia produces HL deficiency. However, the relation between human insulin-dependent Diabetes Mellitus (IDDM), HL activity and the characteristics of LDL have not been studied. The objective of our study is to evaluate the relation between HL activity and the chemical composition of LDL in treated IDDM patients. Subjects were 15 IDDM patients and 15 controls (C), matched for sex and body mass index (BMI). The IDDM patients were classified by the WHO criteria, were free of nephropathy and hypothyroidism, and received no medication except insulin. Controls were clinically healthy and normolipidemic with no family history of diabetes. The IDDM group was divided into two subgroups: subgroup IDDM-A (n = 9) with HL values > 4.3 and IDDM-B (n = 6) with HL < than 4.2 mu-moles glycerol/ml h. The HL in IDDM was lower than in C (p < 0.001). Table 1 shows clinical data. Blood samples were drawn after 12 h fasting. Percentage of HbAlc and plasma concentrations of glucose, total cholesterol, LDL-cholesterol, HDL-cholesterol and TG were assayed. LDL was separated by sequential ultracentrifugation at densities of 1.019-1.063 g/ml and its chemical composition was analyzed. The most relevant results were: plasma TG concentration was higher in IDDM than in C (p < 0.05) (Table 2), although average values DMID not exceed the reference values of 200 mg/dl. The TG-LDL were higher in IDDM than in C: 24.8 +/- 2.7 vs 17.5 +/- 1.1 mg/dl plasma, media +/- SE, (p < 0.02). This difference reflected the values of IDDM-B, whose plasma concentrations of TG-LDL were higher than in C: 32.3 +/- 3.6 vs 17.5 +/- 1.1 mg/dl (p < 0.001), and also higher than in IDDMA (p < 0.02). (Table 3). The chemical composition of LDL in IDDM-B contained a higher percentage of TG than C: 8.5 +/- 0.7 vs 6.8 +/- 0.3 percent (p < 0.05), a lower percentage of cholesterol than IDDM-A: 39.0 +/- 1.7 vs 45.2 +/- 2.2 percent (p < 0.05) and also a larger percentage of proteins than IDDM-A: 28.9 +/- 1.9 vs 20.8 +/- 1.0 percent (p < 0.01). The correlations between TG/cholesterol and HL activity in IDDM were r = -0.53 (p < 0.05) and in IDDM-B, r = -0.81 (p = 0.05). The noteworthy result of this study is the modification of the LDL particle in IDDM, rich in TG in patients with low HL activity. Anomalies in the chemical composition of LDL like those described decrease the uptake of this particle by its physiological B:E receptors. It has recently been demonstrated that LDL is an indissoluble association of lipids and apoproteins, and that both act simultaneously to hold the apoB in a spatial position that expresses normal epitopes. It has been described that particles of LDL rich in TG and poor in cholesterol, shows low affinity for LDL receptors in human fibroblasts. Also in IDDM the interaction of LDL rich in TG with B:E receptors is decreased. This might be one more mechanism contributing to the accelerated atherosclerosis of these patients. Our results suggest that there may be a threshold of HL activity for the complete hydrolysis of the TG of LDL, for the normalization of the TG/cholesterol relation and for the conformation of typical LDL particles.

Lipoproteína de baja densidad rica en triglicéridos y actividad de lipasa hepática en pacientes diabéticos insulino-dependientes / Low density lipoprotein rich in triglycerides and hepatic lipose activity in insulin-dependent diabetic patients

Genetic hepatic lipase (HL) deficiency is associated with low density lipoprotein (LDL) rich in triglycerides (TG), whose affinity for B:E receptors is decreased. In rats, experimental hypoinsulinemia produces HL deficiency. However, the relation between human insulin-dependent Diabetes Mellitus (IDDM), HL activity and the characteristics of LDL have not been studied. The objective of our study is to evaluate the relation between HL activity and the chemical composition of LDL in treated IDDM patients. Subjects were 15 IDDM patients and 15 controls (C), matched for sex and body mass index (BMI). The IDDM patients were classified by the WHO criteria, were free of nephropathy and hypothyroidism, and received no medication except insulin. Controls were clinically healthy and normolipidemic with no family history of diabetes. The IDDM group was divided into two subgroups: subgroup IDDM-A (n = 9) with HL values > 4.3 and IDDM-B (n = 6) with HL < than 4.2 mu-moles glycerol/ml h. The HL in IDDM was lower than in C (p < 0.001). Table 1 shows clinical data. Blood samples were drawn after 12 h fasting. Percentage of HbAlc and plasma concentrations of glucose, total cholesterol, LDL-cholesterol, HDL-cholesterol and TG were assayed. LDL was separated by sequential ultracentrifugation at densities of 1.019-1.063 g/ml and its chemical composition was analyzed. The most relevant results were: plasma TG concentration was higher in IDDM than in C (p < 0.05) (Table 2), although average values DMID not exceed the reference values of 200 mg/dl. The TG-LDL were higher in IDDM than in C: 24.8 +/- 2.7 vs 17.5 +/- 1.1 mg/dl plasma, media +/- SE, (p < 0.02). This difference reflected the values of IDDM-B, whose plasma concentrations of TG-LDL were higher than in C: 32.3 +/- 3.6 vs 17.5 +/- 1.1 mg/dl (p < 0.001), and also higher than in IDDMA (p < 0.02). (Table 3). The chemical composition of LDL in IDDM-B contained a higher percentage of TG than C: 8.5 +/- 0.7 vs 6.8 +/- 0.3 percent (p < 0.05), a lower percentage of cholesterol than IDDM-A: 39.0 +/- 1.7 vs 45.2 +/- 2.2 percent (p < 0.05) and also a larger percentage of proteins than IDDM-A: 28.9 +/- 1.9 vs 20.8 +/- 1.0 percent (p < 0.01). The correlations between TG/cholesterol and HL activity in IDDM were r = -0.53 (p < 0.05) and in IDDM-B, r = -0.81 (p = 0.05). The noteworthy result of this study is the modification of the LDL particle in IDDM, rich in TG in patients with low HL activity. Anomalies in the chemical composition of LDL like those described decrease the uptake of this particle by its physiological B:E receptors. It has recently been demonstrated that LDL is an indissoluble association of lipids and apoproteins, and that both act simultaneously to hold the apoB in a spatial position that expresses normal epitopes. It has been described that particles of LDL rich in TG and poor in cholesterol, shows low affinity for LDL receptors in human fibroblasts. Also in IDDM the interaction of LDL rich in TG with B:E receptors is decreased. This might be one more mechanism contributing to the accelerated atherosclerosis of these patients. Our results suggest that there may be a threshold of HL activity for the complete hydrolysis of the TG of LDL, for the normalization of the TG/cholesterol relation and for the conformation of typical LDL particles.(AU)

Colesterol-IDL y/o colesterol-ß-VLDL: un nuevo parámetro en diferentes fenotipos lipoprotéicos / IDL- an/or ß-VLDL cholesterol: a new parameter in different lipoproteic phenotypes

IDL y/o ß-VLDL son consideradas una lipoproteína aterogénica. Nuestro objetivo es evaluar su concentración plasmática en diferentes fenotipos primarios y secundarios de dislipemia (según OMS). Se definió normolipemia de acuerdo a colesterol (C) total *200 mg/dl, triglicéridos *170 mg/dl, C-LDL *160 mg/dl, C-HDL *40 mg/dl y ausencia de "ß-ancha" en el lipodograma electroforético. El percentilo 90 de la concentración de C-IDL previamente hallado en 30 controles sanos fue 12 mg/dl. Los datos obtenidos no reflejan necesariamente la distribución de fenotipos y patologías en la población general, debido a que se obtuvieron en un laboratorio de referencia. Entre 99 pacientes normolipénicos (NL), cuya Xñ DS fue de 8,8 ñ 6,5 mg/dl, se encontró un subgrupo de 22 con C-IDL > 12 mg/dl cuya Xñ DS fue 18,7 ñ 5,3 mg/dl. En el fenotipo IIa la Xñ fue 12,3 ñ 8,3 mg/dl (n=40). En el fenotipo IIb la Xñ DS fue 16,4 ñ 7,9 mg/dl (n=20). Los fenotipos III y V presentaron en todos los casos C-IDL elevado (Xñ DS = 64,6 ñ 28,6 y 19,2 ñ 3,2 mg/dl respectivamente). En el fenotipo IV la Xñ DS fue 22,6 ñ 11,6 mg/dl (n=10). Todos los fenotipos presentaron C-IDL mayor que los NL (p<0.05 o menor, test U-Mann Whitney). El 22%de los pacientes "aparentemente" NL tenían C-IDL > 12 mg/dl, siendo éstos postmenopáusicas, diabéticos u obesos. De estos datos surge la conveniencia de incluir la medida de C-IDL en el seguimiento de estas patologías y de los fenotipos IIb, III, IV y V

Colesterol-IDL y/o colesterol-ß-VLDL: un nuevo parámetro en diferentes fenotipos lipoprotéicos / IDL- an/or ß-VLDL cholesterol: a new parameter in different lipoproteic phenotypes

IDL y/o ß-VLDL son consideradas una lipoproteína aterogénica. Nuestro objetivo es evaluar su concentración plasmática en diferentes fenotipos primarios y secundarios de dislipemia (según OMS). Se definió normolipemia de acuerdo a colesterol (C) total *200 mg/dl, triglicéridos *170 mg/dl, C-LDL *160 mg/dl, C-HDL *40 mg/dl y ausencia de "ß-ancha" en el lipodograma electroforético. El percentilo 90 de la concentración de C-IDL previamente hallado en 30 controles sanos fue 12 mg/dl. Los datos obtenidos no reflejan necesariamente la distribución de fenotipos y patologías en la población general, debido a que se obtuvieron en un laboratorio de referencia. Entre 99 pacientes normolipénicos (NL), cuya Xñ DS fue de 8,8 ñ 6,5 mg/dl, se encontró un subgrupo de 22 con C-IDL > 12 mg/dl cuya Xñ DS fue 18,7 ñ 5,3 mg/dl. En el fenotipo IIa la Xñ fue 12,3 ñ 8,3 mg/dl (n=40). En el fenotipo IIb la Xñ DS fue 16,4 ñ 7,9 mg/dl (n=20). Los fenotipos III y V presentaron en todos los casos C-IDL elevado (Xñ DS = 64,6 ñ 28,6 y 19,2 ñ 3,2 mg/dl respectivamente). En el fenotipo IV la Xñ DS fue 22,6 ñ 11,6 mg/dl (n=10). Todos los fenotipos presentaron C-IDL mayor que los NL (p<0.05 o menor, test U-Mann Whitney). El 22%de los pacientes "aparentemente" NL tenían C-IDL > 12 mg/dl, siendo éstos postmenopáusicas, diabéticos u obesos. De estos datos surge la conveniencia de incluir la medida de C-IDL en el seguimiento de estas patologías y de los fenotipos IIb, III, IV y V