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El factor de necrosis tumoral alfa regula el factor de crecimiento similar a la insulina 1 y la expresión de la
A Anwar1, A A Zahid, K J Scheidegger
1Division of Cardiology, University Hospital of Geneva, Switzerland.
Circulation
|March 13, 2002
Resumen
El factor de necrosis tumoral alfa (TNF-alfa) reduce el factor de crecimiento similar a la insulina-1 (IGF-1) y aumenta la proteína de unión al IGF-3 (IGFBP-3) en las células musculares lisas vasculares. Esta regulación a la baja de IGF-1 por el TNF-alfa puede promover la inestabilidad de la placa en los síndromes coronarios.
Área de la Ciencia:
- Biología cardiovascular Biología cardiovascular
- La medicina molecular es una medicina molecular.
- La investigación de la aterosclerosis en la investigación de la aterosclerosis.
Sus antecedentes:
- Los mediadores inflamatorios como el TNF-alfa pueden afectar la integridad de la placa coronaria al alterar la supervivencia del VSMC y la matriz extracelular.
- Se sabe que el factor de crecimiento similar a la insulina-1 (IGF-1) previene la apoptosis y promueve la formación de la matriz, contrarrestando algunos efectos inflamatorios.
Objetivo del estudio:
- Investigar los efectos de las citoquinas clave en el sistema IGF-1 dentro de las células del músculo liso vascular (VSMC).
- Para aclarar el papel del TNF-alfa en la regulación de IGF-1 y las proteínas de unión a IGF (IGFBPs) en VSMCs.
Principales métodos:
- Los VSMC aórticos en ratas fueron tratados con varias concentraciones de TNF-alfa, IL-1beta, IL-6 e IFN-gamma.
- Se analizaron la expresión génica (ARNm) y los niveles de proteínas de IGF-1 e IGFBP-3.
- Se evaluaron los mecanismos de transcripción utilizando actinomicina D.
- Los efectos funcionales se evaluaron utilizando anticuerpos anti-IGFBP-3 y ensayos de apoptosis.
Principales resultados:
- TNF-alfa disminuyó significativamente el ARNm de IGF-1 y aumentó el ARNm y la proteína de IGFBP-3 en los VSMC.
- Otras citocinas probadas (IL-1beta, IL-6, IFN-gamma) no afectaron el sistema IGF-1.
- El aumento de los niveles de IGFBP-3 se correlacionó con la reducción de la síntesis de ADN VSMC, mientras que los análogos de IGF-1 redujeron la apoptosis.
Conclusiones:
- El TNF-alfa regula a la baja el IGF-1 y regula al alza el IGFBP-3 en los VSMC, lo que probablemente reduzca el IGF-1 bioactivo.
- Esta reducción mediada por el TNF-alfa en el IGF-1 puede contribuir a la disminución de la viabilidad de los VSMC y la inestabilidad de la placa en los síndromes coronarios.
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