Accelerated wound repair, cell proliferation, and collagen accumulation are produced by a cartilage-derived growth factor.

Abstract

Cartilage-derived growth factor (CDGF), a cationic polypeptide of ~18,000 mol wt, was prepared from bovine articular cartilage; other sources were bovine and human scapular and costal cartilage. Previous studies have shown that CDGF stimulates the proliferation of cultured mouse fibroblasts as well as chondrocytes and endothelial cells from various sources. In this study, CDGF was shown to stimulate dose-dependently the accumulation of DNA and collagen by rat embryo fibroblasts and a population of fibroblasts derived from granulation tissue. CDGF also stimulated the proliferation of cultured bovine capillary endothelial cells dose-dependently. To evaluate the effects of CDGF in vivo, we implanted polyvinyl alcohol sponges subcutaneously in rats. 6 d postimplantation, sponges were injected with 300 pg of partially purified CDGF, a dose which takes into account the cell numbers in the sponges as compared with cell cultures. CDGF rapidly disappeared from the sponges and only ~10% of the initial dose was present at 4 h. Despite its transient presence, CDGF caused a relative increase in sponge DNA content of 2.6-fold at 48 h and 2.4-fold at 72 h. We repeated the sponge experiment by using 500-ng injections of CDGF purified to near homogeneity by heparin-Sepharose chromatography. Purified CDGF caused significant increases in sponge collagen, protein, and DNA content at 48 and 72 h after a single injection. The effects of CDGF were abolished by heat and unaffected by reduction of disulfide linkages. Morphologically, CDGF did not evoke an inflammatory response, and its effect on proliferating endothelial cells and fibroblasts was, therefore, probably direct. However, increases in DNA content of sponges could not be fully accounted for by increased DNA synthesis, which suggests that recruitment may be an important component of the in vivo response. Taken together, the effects of CDGF on cultured cells and granulation tissue suggest that the sustained presence of CDGF in vivo may greatly enhance its effects upon wound repair.A number of polypeptide growth factors that stimulate the proliferation of cells in culture have been described in the last decade. These include epidermal growth factor, fibroblast growth factor, and platelet-derived growth factor (5,6,17). Many of the growth factors are large polypeptides that have specific receptor-mediated interactions with their target cells, and such interactions are associated with cell proliferation in vitro. By contrast, the efficacy of growth factors in vivo is not nearly so clearly established. This is in part the result of the difficulty of administering growth factors and measuring their cellular response in vivo.The cartilage-derived growth factor (CDGF)' is a cationic polypeptide with a molecular weight of ~ 18,000 which can 1 Abbreviations used in this paper. BCE, bovine capillary endothelial; CDGF, cartilage-derived growth factor; DME, Dulbecco's modified Eagle's medium; FCS, fetal calf serum; TCA, trichloroacetic acid.

Expression of a binding protein for FGF is associated with epithelial development and skin carcinogenesis

“…FGF-2 plays inductive roles during embryogenesis, wound healing and stimulates angiogenesis (Broadlay et al, 1989;Davidson et al, 1985;Hori et al, 1991;Shing et al, 1985). It is found ubiquitously in adult tissues and in many tumors where it appears bound to proteoglycan molecules of the EM (Aviezer et al, 1994;Moscatelli et al, 1991).…”

“…FGF-2 is expressed in the dermis of normal skin (Werner et al, 1993) as well as in tissues from patients with SCC of the head and neck (Huang et al, 1993;Schultz-Hector and Haghayegh, 1993). FGF-2 has been shown to play an essential role during wound healing (Broadley et al, 1989;Davidson et al, 1985) and to stimulate the proliferation of keratinocytes and a number of other cell types including ®broblasts and endothelial cells in vitro (Brem and Klagsbrun, 1993;Schweigerer et al, 1987).…”

Isolation and characterization of a macrophage-derived heparin-binding growth factor.

“…With the exception of bFGF and IL-1, macrophage-derived growth factors are secreted and act ostensibly in a paracrine manner. bFGF is known to stimulate processes such as formation of granulation tissue and angiogenesis (Davidson et al, 1985;Shing et al, 1985;Folkman and Klagsbrun, 1987;Klagsbrun, 1989). However, as a cell-associated growth factor, the mechanism by which macrophagederived bFGF could stimulate these processes is unclear.…”

Sustained release of epidermal growth factor accelerates wound repair.

“…This system was devised because it has been suggested that the effect of growth factors can be modulated by controlling their availability to cell surface receptors (11) and because of our earlier observation that cartilage-derived growth factor (CDGF), an accelerator of wound repair, disappeared rapidly from sites of Injection (12 Savage and Cohen (13) and this crude extract was purified by HPLC procedures (14). The purity of EGF was determined by NaDodSO4/PAGE, amino acid analysis, and sequence analysis, and its concentration was measured by amino acid analysis.…”

“…The remainder of each sponge was minced finely in medium (Dulbecco's modified Eagle's medium) containing antibiotics (penicillin, 100 units/ml; streptomycin, 100 4g/ml). Minces were incubated as described (12). More than 95% of the newly synthesized collagen was recovered by combining three vigorous washes of the minces in phosphate-buffered saline together with incubation medium.…”