The effect of fibronectin therapy and fibronectin deficiency on healing of rat burns and excision wounds

Reversal of gelatin-impaired wound healing in rats by exogenous fibronectin

Animal experiments have shown that administration of gelatin results in a deprivation of plasma fibronectin (FN) and impaired wound healing. For further elucidation of these findings a therapy study with purified human FN was performed in rats. Fifty animals received a standard burn injury of 1% body surface and were divided into five experimental groups. Positive controls given no further treatment or treated with solvent only served for estimation of normal healing. For a negative control, 10 animals received three intraperitoneal injections of gelatin (58 mg/kg body wt) on Days 0, 1, and 2 after injury. They exhibited a striking lack of plasma FN (Day 1) and a significant delay of wound contraction (Days 7 and 14). In the therapy groups each administration of gelatin was followed by an intraperitoneal or intracardiac injection of FN (58 mg/kg body wt) 1 hr later. In these animals the negative effect of gelatin upon plasma FN and wound contraction was prevented. According to this study wound healing is menaced by FN deficiency and can be optimized by substitution of exogenous FN.

RGD-albumin conjugate: expression of tissue regeneration activity

Albumin conjugated with Arg-Gly-Asp (RGD) has cellular adhesive activity comparable to that of fibronectin in vitro. This study examined whether RGD-albumin conjugate (RGD-ALB) can promote soft tissue ingrowth into a porous matrix in vivo. Polyurethane sponges with 150-500 microns pore size adsorbed with RGD-ALB, fibronectin and albumin were implanted in the subcutaneous tissue of rats. The RGD-ALB-adsorbed sponge exhibited tissue ingrowth comparable to that of the fibronectin-adsorbed sponge at the early period of implantation. On the other hand, the tissue ingrowth was markedly retarded for non-adsorbed and albumin-adsorbed sponges. The enhanced tissue ingrowth found for RGD-ALB and fibronectin was deduced to be mainly a result of its cell-adhesion activity. It is concluded that RGD-ALB exhibits tissue ingrowth-promoting activity at the initial stage of wound healing as effectively as fibronectin.

[Early phase of healing of anastomoses with special reference to peritonitis and ischemia]

Experimental sutureless colonic anastomosis was evaluated under various conditions during the first 24 postoperative hours. Adaptation of large bowel segments was achieved by interrupted inverting sutures, which were removed after one hour. This short adaptation period was sufficient for fibrinous contact of bowel segments. Breaking strength of intestinal anastomosis was determined under normal conditions, in peritonitis, complete ischemia and unilateral ischemia of one bowel segment. As control parameter breaking strength of conventional anastomosis was determined under normal conditions. We obtained the following results: 1) Sutureless anastomosis exhibited significantly lower breaking strength than conventional anastomosis. 2) Sutureless anastomosis showed a significant increase in breaking strength under normal conditions after the first 6 h, on the contrary breaking strength remained at lower levels in peritonitis. 3) In complete ischemia anastomotic failure was observed even after 3 h of adaptation. Therefore breaking strength was not measurable. 4) Under unilateral ischemia breaking strength of intestinal anastomosis was significantly lower than under normal conditions.