Synthetic Polypentapeptide of Elastin for Initiating Calcification

摘要

A polypentapeptide (PPP) of tropoelastin having a repeating amino acid sequence of (Val-Pro-Gly-Val-Glyn) was evaluated for its potential to initiate in vivo calcification and to enhance bone formation in nonhealing calvarial wounds (8.0 mm) in 396 adults Walter Reed rats. There were four configurations of the PPP (molecular weight range of 50-100K dalton) consisting of 1-dry PPP; 2-coacervate PPP; 3-gamma irradiated, cross-linked PPP; 4-calcified, gamma irradiated, cross-linked PPP. These four iterations plus a control group of animals constituted the five treatment and 36 rats for the control. Following euthanitization, specimens were placed into 70% ethanol, embedded in polymethyl methacrylate, sectioned at 3.5 micrometers, and alternating sections were stained with Masson-Goldner trichrome and von Kossa stains. Histomorphometric analysis was accomplished using a Zeiss Universal microscope (250x) and Videoplan Image Analysis System to evaluate five random histologic fields from margin to margin of the craniotomy. Trabecular bony volume and area of calcification islands were quantitated. These data provide the first in vivo demonstration of the validity of the neutral site binding/charge neutralization mechanism of calcification. Although the synthetic peptide did support calcification, in no group was new bone formed in the craniotomies. Keywords: Polypentapeptide, Calcification, Histomorphometry, Bone repair, Reprints. (AW)