Elastin Content Correlates With Human Disc Degeneration in the Anulus Fibrosus and Nucleus Pulposus.

Cloyd, Jordan M. and Elliott, Dawn M.

Recently, an abundant and organized network of elastic fibers was observed in nondegenerated human disc using immunostaining histochemistry, suggesting a functional role for elastin. While degenerative changes in the disc extracellular matrix composition are well known, changes in elastin content that may accompany degeneration have not been reported.  The objective of this study was to measure the site-specific changes in elastin content that accompany disc degeneration using a quantitative, dye-binding assay to assess elastin levels.  Human discs were assigned a degenerative grade by 3 independent orthopedic surgeons based on gross morphology. Samples were taken from the outer anulus fibrosus (OAF), inner AF (IAF) and nucleus pulposus (NP). Elastin content was measured using a specific, dye-binding assay and normalized to dry weight and collagen content, which was measured via a hydroxyproline assay.The authors concluded that based on the location-dependent degenerative changes, with highest increases in the IAF, elastin may function to restore lamellar structure under radial loads that potentially cause delamination.

Spine.    2007, 32(17), 1826-1831.

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