Asociación de variantes funcionales en genes del metabolismo de la homocisteína con riesgo de trombosis venosa profunda e hiperhomocisteinemia en individuos del Sur de Chile / Association of functional variants in homocysteine metabolism genes, deep venous thrombosis risk and hyperhomocysteinemia in Southern Chilean subjects

Introducción: La Trombosis Venosa Profunda (TVP) es un importante problema de salud en la sociedad moderna. Evidencia reciente sugiere una asociación entre variantes funcionales en genes del metabolismo de la homocisteína con TVP. Sin embargo, los resultados entre poblaciones son contradictorios. En este trabajo, evaluamos la potencial asociación entre la presencia de polimorfismos en genes del metabolismo de la homocis-teína y susceptibilidad a TVP e hiperhomocisteinemia en sujetos chilenos. Métodos: Un total de 231 individuos, 77 pacientes con diagnóstico de TVP y 154 controles fueron incluidos en el estudio. Polimorfismos en los genes Metilenotetrahi-drofolato reductasa (MTHFR) y Cistationina p-sintetasa fueron genotipificados por PCR-RFLP Las concentraciones de homocisteína basal fueron cuantificadas mediante Inmunoensayo de Fluorescencia Polarizada. Resultados: La distribución genotípica y frecuencias alélicas del polimorfismo MTHFR C677T fue significativamente diferente entre pacientes y controles (p<0.01). Odds Ratio para TVP asociada al genotipo homocigoto fue 3.68 (I.C. 95 por ciento: 1.628-8.337, p<0.01). Por el contrario, la distribución genotípica de la variante CBS 844ins68 fue similar en ambos grupos (OR=1.82, I.C. 95 por ciento: 0.636-5.234, p=0.257). Además, los portadores del genotipo homocigoto MTHFR 677TT presentaron niveles más elevados de homocisteína plasmática. Conclusiones: El polimorfismo MTHFR C677T constituye un biomarcador de riesgo de TVP en población chilena, y se relaciona a mayores niveles de homo-cisteína en sujetos homocigotos. Los resultados sugieren que la detección molecular de esta variante debería ser incluida en el estudio básico de Trombofilia en nuestra población.

Background: Deep Venous Thrombosis (DVT) is an important health problem in modern society. Recent evidence suggests an association between functional variants in homocysteine metabolism genes and DVT. However, findings in different populations have been contradictory. In this work, we evaluated the potential association between the presence of polymorphisms in homocysteine metabolism genes, DVT susceptibility and hyperhomocysteinemia in Chilean subjects. Methods: A total of 231 individuals, 77 patients with diagnosis of DVT and 154 controls were included in this study. Common variants in Metylenete-trahydrofolate reductase (MTHFR) and Cistationine p-synthetase (CBS) genes were genotyped by PCR-RFLP. Basal homocysteine was quantified by Fluorescence Polarization Immunoassay. Results: Genotype distribution and allelic frequencies of MTHFR C677T polymorphism were significantly different between patients and controls. Odds Ratio for DVT associated to homozygous status was 3.68 (95 percent C.I., 1.628-8.337, p<0.01). On the other hand, the genotype distribution of the CBS 844ins68 variant was similar in both groups (OR 1.82, 95 percent C.I.: 0.636-5.234, p=0.257). In addition, the individuals carrying the MTHFR 677TT homozygous genotype exhibited higher levels of homocysteine. Conclusion: The MTHFR C677T polymorphism constituted a molecular biomarker of DVT in Chilean population, and related to higher levels of homocysteine in homozygote subjects. The results suggest that the molecular detection of this polymorphism should be included in the basic screening for thrombophilia in our population.

Comparison of anticoagulant effects on vein grafts between human TFPI gene transfection and aspirin oral administration / 华中科技大学学报（医学）（英德文版）

To develop a more efficient antithrombotic way after coronary artery bypass grafting (CABG), the anticoagulant effects were compared of human tissue factor pathway inhibitor (TFPI) gene transfection and aspirin oral administration (traditional method) on vein grafts. An eukaryotic expression plasmid pCMV-(Kozak) TFPI was prepared. Animal model of carotid artery bypass grafting was constructed. In operation, endothelial cells of vein grafts in TFPI group and empty plasmid control group were transfected with pCMV-(Kozak) TFPI and empty plasmid pCMV respectively, while no transfection was conducted in aspirin control group. After operation, aspirin (2 mg.kg(-1).(-1)) was administered (i.g.) in aspirin control group. Three days later, grafts (n=10) were harvested for RT-PCR, Western blotting and immunohistochemical analyses of exogenous gene expression and for pathological, scanning electron microscopic observation of thrombus. Thirty days later, the patency rates of remnant grafts (n=10) were recorded by vessel Doppler ultrasonography. Human TFPI gene products were detected in gene transferred vein grafts. Three days later, thrombi were found in 7 animals of aspirin control group and in 8 animals of empty plasmid control group, but in only 1 of TFPI group (P<0.01). Thirty days later, 5 grafts were occluded in empty plasmid control group, but none of grafts was occluded in the other groups (P<0.05). The endothelial surfaces of grafts in both of the control groups were covered with aggregated erythrocytes and platelets, and it were not seen in TFPI group. It was suggested that the anticoagulant effects on vein grafts of human TFPI gene transfection are better than those of aspirin.