ELASTIN AND FIBRILLIN MESSENGER-RNA AND PROTEIN-LEVELS IN THE ONTOGENY OF NORMAL HUMAN AORTA

Elastin associated microfibrils (EAMF) are ubiquitous connective tissu e structures that are believed to provide tensile strength and flexibi lity to numerous tissues. In this study the ontogeny of EAMF in normal human aorta was examined using immunohistochemical analysis of fibril lin, an EAMF component, and mRNA levels of fibrillin and elastin. Spec imens of infra-renal aorta from ages 11 months to 44 years were obtain ed following organ procurement. Decreasing amounts, as judged by compu ter digitized image analysis, of immunoreactive fibrillin when compare d to elastin auto-fluorescence were observed in aortic sections with i ncreasing age. Elastase treatment would un-mask the anti-fibrillin rea ctive epitope reinforcing the suggestion that EAMF act as a ''scaffold '' for elastin deposition. Northern and dot blot hybridizations demons trated a decrease in relative fibrillin message levels with increasing age. The abundance of fibrillin in relation to elastin may suggest a role for EAMF independent of their association with elastin.