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Demostración de disfunción endotelial vascular de inicio rápido después de hiperhomocisteinemia: un efecto reversible

J C Chambers¹, A McGregor, J Jean-Marie

¹National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, London, UK.

|March 9, 1999

Resumen

Los niveles elevados de homocisteína perjudican agudamente la función endotelial vascular, un proceso relacionado con el estrés oxidativo. El pretratamiento con vitamina C previene esta disfunción en individuos sanos, lo que sugiere un papel protector contra el daño vascular inducido por la homocisteína.

Área de la Ciencia:

Investigaciones Cardiovasculares Investigación Cardiovascular Investigaciones Cardiovasculares
Biología Vascular Biología Vascular
Ciencias de la Nutrición Ciencias de la Nutrición

Sus antecedentes:

La hiperhomocisteinemia es un factor de riesgo significativo para la enfermedad vascular.
Todavía no están claros los mecanismos precisos por los cuales la homocisteína contribuye a la aterosclerosis.
El estrés oxidativo está implicado en la disfunción endotelial mediada por homocisteína.

Objetivo del estudio:

Investigar la asociación entre las concentraciones elevadas de homocisteína y la disfunción endotelial aguda.
Para determinar si la vitamina C puede prevenir la disfunción endotelial inducida por la homocisteína.
Para explorar el papel de los mecanismos de estrés oxidante en este proceso.

Principales métodos:

17 voluntarios sanos se sometieron a un desafío oral de L-metionina para inducir hiperhomocisteinemia.
Las respuestas del diámetro de la arteria braquial (dependientes del endotelio e independientes) se midieron utilizando ultrasonido de alta resolución.
Las mediciones se tomaron al inicio, 2 y 4 horas después de la metionina, con y sin pretratamiento de vitamina C.

Principales resultados:

La L-metionina oral aumentó significativamente los niveles plasmáticos de homocisteína y redujo la dilatación mediada por flujo.
Se observó una fuerte correlación inversa entre la concentración de homocisteína y la dilatación mediada por flujo.
El pretratamiento con vitamina C no alteró los niveles de homocisteína, pero mejoró significativamente la reducción de la dilatación mediada por flujo.

Conclusiones:

La elevación aguda de la homocisteína afecta la función endotelial vascular en sujetos sanos.
El pretratamiento con vitamina C previene eficazmente esta disfunción endotelial aguda.
Estos hallazgos apoyan la hipótesis de que la homocisteína ejerce efectos vasculares adversos a través de mecanismos de estrés oxidativo.

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