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The chemical structure of lipoprotein (a) is similar to that of LDL, from which it differs due to the presence of apolipoprotein (a) bound to apo B100 via one disulfide bridge. Lipoprotein (a) is synthesized in the liver and its plasma concentration, which can be determined by use of monoclonal antibody-based methods, ranges from < 1 mg to > 1,000 mg/dL. Lipoprotein (a) levels over 20-30 mg/dL are associated with a two-fold risk of developing coronary artery disease. Usually, black subjects have higher lipoprotein (a) levels that, differently from Caucasians and Orientals, are not related to coronary artery disease. However, the risk of black subjects must be considered. Sex and age have little influence on lipoprotein (a) levels. Lipoprotein (a) homology with plasminogen might lead to interference with the fibrinolytic cascade, accounting for an atherogenic mechanism of that lipoprotein. Nevertheless, direct deposition of lipoprotein (a) on arterial wall is also a possible mechanism, lipoprotein (a) being more prone to oxidation than LDL. Most prospective studies have confirmed lipoprotein (a) as a predisposing factor to atherosclerosis. Statin treatment does not lower lipoprotein (a) levels, differently from niacin and ezetimibe, which tend to reduce lipoprotein (a), although confirmation of ezetimibe effects is pending. The reduction in lipoprotein (a) concentrations has not been demonstrated to reduce the risk for coronary artery disease. Whenever higher lipoprotein (a) concentrations are found, and in the absence of more effective and well-tolerated drugs, a more strict and vigorous control of the other coronary artery disease risk factors should be sought.

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The chemical structure of lipoprotein (a) is similar to that of LDL, from which it differs due to the presence of apolipoprotein (a) bound to apo B100 via one disulfide bridge. Lipoprotein (a) is synthesized in the liver and its plasma concentration, which can be determined by use of monoclonal antibody-based methods, ranges from < 1 mg to > 1,000 mg/dL. Lipoprotein (a) levels over 20-30 mg/dL are associated with a two-fold risk of developing coronary artery disease. Usually, black subjects have higher lipoprotein (a) levels that, differently from Caucasians and Orientals, are not related to coronary artery disease. However, the risk of black subjects must be considered. Sex and age have little influence on lipoprotein (a) levels. Lipoprotein (a) homology with plasminogen might lead to interference with the fibrinolytic cascade, accounting for an atherogenic mechanism of that lipoprotein. Nevertheless, direct deposition of lipoprotein (a) on arterial wall is also a possible mechanism, lipoprotein (a) being more prone to oxidation than LDL. Most prospective studies have confirmed lipoprotein (a) as a predisposing factor to atherosclerosis. Statin treatment does not lower lipoprotein (a) levels, differently from niacin and ezetimibe, which tend to reduce lipoprotein (a), although confirmation of ezetimibe effects is pending. The reduction in lipoprotein (a) concentrations has not been demonstrated to reduce the risk for coronary artery disease. Whenever higher lipoprotein (a) concentrations are found, and in the absence of more effective and well-tolerated drugs, a more strict and vigorous control of the other coronary artery disease risk factors should be sought.

A partícula de lipoproteína (a) apresenta estrutura semelhante à da LDL, diferenciando-se pela presença da apolipoproteína (a) ligada por uma ponte dissulfeto à apolipoproteína B. Sua síntese ocorre no fígado e sua concentração plasmática varia de < 1 mg a > 1.000 mg/dL, podendo ser dosada de rotina em laboratório clínico por método baseado em anticorpos monoclonais. Acima de 20 a 30 mg/dL o risco de desenvolvimento de doença cardiovascular aumenta em cerca de duas vezes, o que não é válido para os afrodescendentes, que já apresentam normalmente níveis mais altos dessa lipoproteína, do que caucasianos e orientais. Entretanto, o risco para indivíduos negros também deve ser levado em conta. Gênero e idade exercem pouca influência na concentração de lipoproteína (a). A homologia com o plasminogênio, que interfere na cascata fibrinolítica, pode ser um mecanismo da aterogenicidade da lipoproteína (a). Entretanto, a deposição direta na parede da artéria também é um dos mecanismos possíveis, sendo a lipoprotrína (a) mais oxidável do que a LDL. De forma geral estudos prospectivos confirmam a lipoproteína (a) como fator predisponente à aterosclerose. O uso de estatinas não interfere no nível da lipoproteína (a), diferentemente da niacina e da ezetimiba, que promovem sua diminuição, embora essa última dependa de confirmação. Não está demonstrado que a redução de lipoproteína (a) resulte em diminuição de risco de doença arterial coronária. Diante de concentrações mais elevadas de lipoproteína (a) e na falta de medicações mais efetivas e de boa tolerabilidade, deve-se, pelo menos, procurar controlar, de forma mais rigorosa, os outros fatores de risco de doença arterial coronária.

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Lipoprotein-A (LpA) is an emerging independent risk factor for cerebro- and cardio-vascular diseases (CCVD). Recognizing its function and its normal distribution is of fundamental importance for a better understanding of CCVD patho-physiology. The present study evaluated plasma LpA levels of healthy university students using turbidimetric methods. Medians and inter-quartile differences obtained for male and female participants were 11.3mg/dL (3.1-30.7) and 20.9mg/dL (6.5-42.3), respectively, demonstrating a significant difference (P=0.017) between men and women. A third of students showed plasma concentrations above reference values. Our results indicate that 33% of students possess a hidden independent risk factor for CCVD. Multi-disciplinary evaluation and characterization of young individuals should be recommended in an attempt to take early preventive measures and to eliminate possible modifiable risk factors such as sedentary lifestyle, smoking, hypertension, obesity and atherogenic diet.

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INTRODUÇÃO: A doença arterial obstrutiva periférica (DAOP) constitui um excelente marcador para a aterosclerose sistêmica. Entre os fatores de risco para essa doença está o diabetes mellitus tipo 2 (DM2). Acredita-se que a lipoproteína (a) [Lp(a)] esteja ligada a risco aumentado de aterosclerose, embora os mecanismos que levem a esse aumento não sejam completamente conhecidos. Níveis elevados de Lp(a) parecem estar associados a risco aumentado de doença arterial coronariana (DAC), assim como DAOP e doença cerebrovascular. OBJETIVO: Avaliar os níveis plasmáticos de Lp(a) e outras variáveis lipídicas em um grupo de pacientes com DAOP e/ou DM2. MATERIAL E MÉTODOS: Níveis plasmáticos de Lp(a), colesterol total (CT), colesterol da lipoproteína de alta densidade (HDL-c), colesterol da lipoproteína de baixa densidade (LDL-c), triglicérides (TG) e apolipoproteínas A-I e B foram medidos em amostras de sangue de 12 indivíduos comprovadamente não-portadores de DAOP e DM2 (controles), 17 pacientes portadores de DAOP, 18 pacientes com DM2 e 19 pacientes portadores de DAOP e DM2 simultaneamente. Os participantes desse estudo foram selecionados buscando-se homogeneidade e semelhança estatística em relação às variáveis sexo, idade e nível socioeconômico. RESULTADOS: A Lp(a) apresentou tendência a elevação tanto no grupo de pacientes com DAOP quanto naquele com DM2 + DAOP. Foram encontradas diferenças significativas entre os grupos para as dosagens de HDL-c e Apo A-I, inclusive com correlação positiva entre esses parâmetros. A relação CT/HDL-c apresentou diferença estatística significativa entre os grupos. Foram observadas correlações positiva entre Lp(a) e LDL-c, e negativa entre o índice tornozelo-braquial (ITB) e a Lp(a). CONCLUSÃO: Para as variáveis lipídicas estudadas foram observadas diferenças estatísticas significativas apenas entre os níveis plasmáticos de HDL-c e Apo A-I. Para o parâmetro Lp(a) foram observados níveis plasmáticos mais elevados...

BACKGROUND: Peripheral arterial obstructive disease (PAOD) constitutes an excellent marker for systemic atherosclerosis and type 2 diabetes mellitus (DM2) is among the greatest risk factors for this disease. It is believed that lipoprotein (a) [Lp(a)] is linked to increased risk of atherosclerosis, although the mechanisms responsible for that are not widely known. Elevated levels of Lp(a) seem to be associated with a higher risk of coronary artery disease (CAD), as well as PAOD and cerebrovascular disease. OBJECTIVES: To assess the plasma levels of Lp(a) and other lipid parameters in patients with PAOD and/or DM2. Material and methods: Plasma levels of Lp(a), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), triglycerides (TG) and apolipoproteins A-I and B were measured in blood samples of 12 subjects carrying neither PAOD nor DM2 (control group), 17 patients with PAOD, 18 with DM2 and 19 with both PAOD and DM2. The subjects selected for this study showed homogeneity and no statistical difference for gender, age, and socioeconomic status. RESULTS: The Lp(a) showed a tendency to elevation both in groups PAOD only and PAOD + DM2 simultaneously. Significant differences were observed among the groups as to HDL-c and apolipoprotein A-I levels, with positive correlation between these two parameters. TC/HDL-c ratio showed significant difference among the groups. Positive correlation was found between Lp(a) and LDL-c, and negative one, between the ankle-arm index and LP(a). CONCLUSION: As to the lipid parameters studied, significant statistical differences were found between HDL-c and apolipoprotein A-I plasma levels only. For Lp(a) parameter, higher plasma levels were observed in PAOD and PAOD + DM2, which have also shown concomitant and significant HDL-c reduction.

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Altas concentraciones de Lipoproteína (a) [Lp)a)] son consideradas un factor de riesgo independiente para la enfermedad cardiovascular, sin embargo su determinación no se realiza como prueba de rutina en la evaluación de dicho riesgo. El propósito de este estudio fue determinar los niveles séricos de Lp(a) en individuos de las poblaciones de Maracaibo, una localidad con predominio blanco-hispánico, y de Bobures, una localidad afrovenezolana, ambas ubicadas en el Estado Zulia, Venezuela. para ello se seleccionaron al azar un total de 112 individuos, 57 de Maracaibo (edad promedio 41,8 ± 13,5 años), y 55 de Bobures (edad promedio 31,4 ± 17,4 años) a los cuales se les determinó en condiciones basales glicemia, perfil lípidico y Lp(a). Para la cuantificación sérica de Lp(a) fue utilizado un Kit comercial basado en ELISA de doble anticuerpo monoclonal contra apo-B100 y contra apo(a) (Heber Biotech BioSCREEN Lp(a), La Habana, Cuba). El colesterol total y el colesterol de HDL fueron significativamente más elevados en los individuos de Maracaibo que en los de Bobures (p<0.009 y p<0.001 respectivamente), mientras que los niveles de Lp(a) séricos fueron significativamente más elevados (p<0.001 en la población afrovenezolana (media de 59,0 mg/dl) que en los blancos hispánicos) (media de 29,0 mg/dl). Nuestros rsultados sugieren que la población afrovenezolana estudiada al tener concentraciones de Lp(a) dos veces más elevada que la muestra de blancos-hispánicos estudiados y por encima del rango normal de 30 mg/dl, tienen un mayor riesgo de enfermedad cardiovascular, por lo tanto deben ser realizados estudios destinados a determinar de los subtipos de Lp(a) presentes en esta población(AU)

High serum Lipoprotein (a) [Lp(a)] concentrations are considered an independent risk factor for cardiovascular disease. Lp(a) is not usually included as a marker in the routine measurement of the evaluation and management of cardiovascular disease. The goal of this study was to determine the serum Lp(a) levels in two Venezuelas population, Maracaibo, a white-hispanic population, and Bobures, an afro-venezuelan population which has a high prevalence of cardiovascular disease. A total of 112 subjects, 57 from Maracaibo (aged 41,8 ± 13,5 years) and 55 from Bobures (aged 31,4 ± 17,4 years), were selected randomly. Fasting glycemia, lipid profile and Lp(a) concentrations were measured throughout. Serum Lp(a) was measured using a commercial kit (Heber Biotech BioSCREEN Lp(a), La Habana, Cuba). Serum total cholesterol and HDL cholesterol levels were significantly higher in Maracaibo than Bobures subjects (p<0.009 and p<0.001 respectively); whereas Lp(a) levels were significantly higher (p<0.001) in afro-venezuelan (mean 59.0 mg/dl) than in white-hispanic subjects (mean 29.0 mg/dl). Our results suggest that afro-venezuelan population had high serum Lp(a) and low HDL-cholesterol concentrations which could be related with the high prevalence of mortality from cardiovascular disease in this population(AU)

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Altas concentraciones de Lipoproteína (a) [Lp)a)] son consideradas un factor de riesgo independiente para la enfermedad cardiovascular, sin embargo su determinación no se realiza como prueba de rutina en la evaluación de dicho riesgo. El propósito de este estudio fue determinar los niveles séricos de Lp(a) en individuos de las poblaciones de Maracaibo, una localidad con predominio blanco-hispánico, y de Bobures, una localidad afrovenezolana, ambas ubicadas en el Estado Zulia, Venezuela. para ello se seleccionaron al azar un total de 112 individuos, 57 de Maracaibo (edad promedio 41,8 ± 13,5 años), y 55 de Bobures (edad promedio 31,4 ± 17,4 años) a los cuales se les determinó en condiciones basales glicemia, perfil lípidico y Lp(a). Para la cuantificación sérica de Lp(a) fue utilizado un Kit comercial basado en ELISA de doble anticuerpo monoclonal contra apo-B100 y contra apo(a) (Heber Biotech BioSCREEN Lp(a), La Habana, Cuba). El colesterol total y el colesterol de HDL fueron significativamente más elevados en los individuos de Maracaibo que en los de Bobures (p<0.009 y p<0.001 respectivamente), mientras que los niveles de Lp(a) séricos fueron significativamente más elevados (p<0.001 en la población afrovenezolana (media de 59,0 mg/dl) que en los blancos hispánicos) (media de 29,0 mg/dl). Nuestros rsultados sugieren que la población afrovenezolana estudiada al tener concentraciones de Lp(a) dos veces más elevada que la muestra de blancos-hispánicos estudiados y por encima del rango normal de 30 mg/dl, tienen un mayor riesgo de enfermedad cardiovascular, por lo tanto deben ser realizados estudios destinados a determinar de los subtipos de Lp(a) presentes en esta población

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O objetivo deste trabalho foi o estudo de parametros bioquimicos (homocisteina,Lp(a), ApoA e ApoB) e biologicos (dilatação arterial endotélio dependente e dilatação arterial após nitrato sublingual) em mulheres com hipotireoidismo sub-clinico;nas pacientes que apresentaram alteração nos parametros biologicos foram estudados novamente todos os parametros,bioquimicos e biologicos após o tratamento com levotiroxina.Os resultados mostraram alteração na dilatação arterial endotélio / The objective of this work was to study biochemical ( homocysteine,Lp(a),ApoA and ApoB) and biological ( endothelium-dependent arterial dilation and arterial dilation after sublingual nitrate) parameters in women with subclinical hypothyroidism;in patients with abnormal biological parameters,biochemical and biological parameters were studied again after levothyroxine therapy.Results show abnormal endothelium-dependent arterial dilation...

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The present study describes a monoclonal antibody-based enzyme immunoassay (ELISA) for the quantitation of lipoprotein(a), Lp(a), in human plasma. Two antibodies to Lp(a), 2F4E7 and 8G12G7, were produced and characterized as specific and high affinity antibodies against Lp(a). A reference control serum was utilized to prepare the standard curve in a Lp(a) concentration range from 0.015 to 0.5 ug/ml. A biotinylated monoclonal antibody against apoB-LDL was used as the second antibody. The comparison of the standardized ELISA using mAb 2F4E7 with an ELISA using a characterized mAb against Lp(a) (clone KO9) as capture antibody showed that the Lp(a) concentration of two standard sera was similar with both assays. Furthermore, when compared with an electroimmunoassay kit, similar Lp(a) concentrations for the standard were also obtained.

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We produced, selected and cloned hybridomas that secrete monoclonal antibodies against human apolipoprotein (apo) A-I. All of the antibodies corresponded to the IgG(1) subclass and were named 1C11, 2B4, 2C10, 7C5, 8A4 and 8A5. The antibodies were characterized by their reactivity with whole lipoproteins, apolipoproteins, synthetic peptides and fragments generated by cleavage of the apo A-I. Three of the monoclonal antibodies studied (2B4, 2C10 and 7C5) were similarly inhibited by an amino-terminal peptide (amino acid sequence 1-20) of apo A-I, whereas antibodies 1C11, 8A4 and 8A5 had no reaction. Other results show that monoclonal antibody 1C11 recognizes an epitope located between amino acids 135-148. We evaluated the monoclonal antibody 8A4 against different HDL subpopulations by competitive displacement analysis and it showed a similar reactivity with the HDL particles: LpA-I and LpA-I:A-II. This antibody was used to standardize a sandwich ELISA to quantitate LpA-I in plasma. We conclude that these monoclonal antibodies are relevant for the study of apo A-I epitope expression and for quantitating apo A-I containing lipoparticles.

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La Lp(a) es una partícula con capacidad aterogénica que ha sido indicada, con resultados contradictorios, como factor de riesgo coronario. En el presente estudio fueron incluídos 121 hombres con hiperlipidemia severa (valores de colesterol > 30 mg/dl), de los cuales 66 tuvieron evidencias de enfermedad coronaria, y un grupo control de 55 hombres. Se realizó un análisis multivariado con regresión logística, incluyendo las siguientes variables: edad, colesterol, HDL-colesterol, triglicéridos, Lp(a). Los resultados del presente estudio sugieren que la Lp(a) es un parámetro de riesgo independiente en hombres con hiperlipidemia severa, por lo cual su determinación permitiría seleccionar entre los sujetos hiperlipidémicos un subgrupo con mayor riesgo de enfermedad coronaria (AU)

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La Lp(a) es una partícula con capacidad aterogénica que ha sido indicada, con resultados contradictorios, como factor de riesgo coronario. En el presente estudio fueron incluídos 121 hombres con hiperlipidemia severa (valores de colesterol > 30 mg/dl), de los cuales 66 tuvieron evidencias de enfermedad coronaria, y un grupo control de 55 hombres. Se realizó un análisis multivariado con regresión logística, incluyendo las siguientes variables: edad, colesterol, HDL-colesterol, triglicéridos, Lp(a). Los resultados del presente estudio sugieren que la Lp(a) es un parámetro de riesgo independiente en hombres con hiperlipidemia severa, por lo cual su determinación permitiría seleccionar entre los sujetos hiperlipidémicos un subgrupo con mayor riesgo de enfermedad coronaria

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Los aumentos de la lipoproteína (a) sérica , (Lp(a)), están asociados a un incremento del riesgo para la aterosclerosis a través de su papel atero-trombótico. Para su dosaje en sangre, se desarrolló un método por electroinmunodifusión. Se utilizó un soporte de agarosa al 1,5 por ciento con 30 por ciento de agar (p/p), disuelto en un buffer tris-glicina-veronal sódico, con antisuero específico anti apo (a) y calibrador liofilizado comerciales. El CV por ciento intra-ensayos fue 6,9 por ciento y el CV por ciento inter-ensayos fue 8,8 por ciento. La linealidad se mantuvo entre 5 y 120 mg/dl. Se midió la Lp(a) en 134 sujetos "aparentemente sanos" de ambos sexos. La distribución de valores no fue gaussiana y tuvo una mediana de 10 mg/dl. El percentil 75 fue 33 mg/dl el cual se consideró "valor de corte", para la detección de sujetos en riesgo; el percentil 90 fue 72 mg/dl. Los valores hallados por este método correlacionaron bien con otro método por ELISA, obteniéndose r = + 0,896, P < 0,000001. El congelamiento de los sueros por 45 días a -20ºC no modificó significativamente los valores, hallándose r = + 0,963, P < 0,000001. Se concluye que el método propuesto puede ser utilizado para la determinación de Lp(a) sérica (AU)

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Los aumentos de la lipoproteína (a) sérica , (Lp(a)), están asociados a un incremento del riesgo para la aterosclerosis a través de su papel atero-trombótico. Para su dosaje en sangre, se desarrolló un método por electroinmunodifusión. Se utilizó un soporte de agarosa al 1,5 por ciento con 30 por ciento de agar (p/p), disuelto en un buffer tris-glicina-veronal sódico, con antisuero específico anti apo (a) y calibrador liofilizado comerciales. El CV por ciento intra-ensayos fue 6,9 por ciento y el CV por ciento inter-ensayos fue 8,8 por ciento. La linealidad se mantuvo entre 5 y 120 mg/dl. Se midió la Lp(a) en 134 sujetos "aparentemente sanos" de ambos sexos. La distribución de valores no fue gaussiana y tuvo una mediana de 10 mg/dl. El percentil 75 fue 33 mg/dl el cual se consideró "valor de corte", para la detección de sujetos en riesgo; el percentil 90 fue 72 mg/dl. Los valores hallados por este método correlacionaron bien con otro método por ELISA, obteniéndose r = + 0,896, P < 0,000001. El congelamiento de los sueros por 45 días a -20ºC no modificó significativamente los valores, hallándose r = + 0,963, P < 0,000001. Se concluye que el método propuesto puede ser utilizado para la determinación de Lp(a) sérica

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