THE ROUTE OF NUTRITION SUPPORT AFFECTS THE EARLY PHASE OF WOUND-HEALING

Background: Nutrition support via the enteral route has been shown to be superior to parenteral administration in maintaining immune functio n, decreasing septic complications, and increasing survival after seve re trauma and surgical injury. Whether the route of nutrition support affects wound healing, another important determinant of outcome follow ing injury, is not known. Methods: Forty-nine Sprague-Dawley rats, 290 to 360 g body wt, underwent identical surgical manipulation consistin g of central venous catheterization, fashioning of gastrostomy and dor sal skin incision, and placement of polyvinyl alcohol sponges into sub cutaneous pockets. Identical infusates of 25% dextrose, 4.25% amino ac ids, and vitamins were given, half the animals receiving the infusion via the gastrostomy and the other half via the venous catheter. Animal s were killed on day 5,7, or 10. Wound breaking strength, sponge hydro xyproline content tan index of wound collagen deposition), and types I and III collagen gene expression were measured. Results: There were n o nutritional differences between the two groups in terms of energy in take, body weight gain, and plasma levels of albumin, total protein, o r urea nitrogen. On day 5 wound breaking strength was significantly hi gher in the enterally supported group (89.3 +/- 130.7 vs 64.9 +/- 40.2 g for the parenteral group, p < .05). This was paralleled by enhanced wound collagen accumulation (182 +/- 19 vs 132 +/- 13 mu g, p < .05). Gene expression of type I, but not type III, collagen also was increa sed in the enterally fed group. There were no differences noted betwee n the two groups in wound healing parameters 7 and 10 days after injur y. Conclusions: The data demonstrate that the route of nutrition admin istration can influence wound healing. The beneficial effect of the en teral feeding route is limited to the early phases of healing.