![]() ![]() Depletion of wound T lymphocytes decreases wound strength and collagen content, while selective depletion of the CD8 + suppressor subset of T lymphocytes enhances wound healing. Though known to be essential to wound healing, the lymphocytes' role in wound healing is not fully defined. Less numerous than macrophages, T-lymphocyte numbers peak at about 1 week post-injury and truly bridge the transition from the inflammatory to the proliferative phase of healing. T lymphocytes comprise another population of inflammatory/immune cells that routinely invades the wound. ![]() Fibroblasts then carry the wound through the proliferative and remodeling phase, synthesizing collagen and releasing growth factors that facilitate epithelialization, angiogenesis, and granulation.Įach of these cell populations and the complex signaling pathways that regulate these stages of wound healing depend on an intact and operational immune system. Subsequently, the macrophages predominate, both numerically and functionally, and release essential growth factors and chemoattractants that signal fibroblasts to migrate into the injured area. As neutrophils arrive, they begin clearing bacteria and cellular debris by phagocytosis. 1 To see this illustration in color, the reader is referred to the web version of this article at As platelets aggregate to provide hemostasis to the injured area, they release chemoattractants that draw inflammatory cells toward the area of injury. Adapted with permission from Witte and Barbul. Macrophages and neutrophils are predominant during inflammation, whereas lymphocytes peak somewhat later and fibroblasts are predominant during the proliferative phase. The time course of the different cells appearing in the wound during the healing process. Research on how immunonutrition affects wound healing has often been extrapolated from or interposed with studies looking at these other clinical outcomes. Most of the literature on immunonutrition explores its impact on a wide variety of important clinical outcomes (ventilator times, hospital stays, rates of infection, and mortality), in which the immune response plays a pivotal role. Although most clinicians agree that the presence of an “ideal” nutritional environment, as yet incompletely defined, is beneficial to the process of wound healing, the nature of this environment and how it should be created is still a matter of significant debate. Many variations in formulation and route of administration have been used with mixed results. In recent years, a number of studies and reviews have evaluated the role of immunomodulating diets (IMDs) or their components in wound healing. Immunonutrition can be defined as the usage of specific nutritional elements in an attempt to modulate the immune system in a way that benefits a certain injury or disease state. Immunonutrition in its current formulation usually includes supplementation with arginine, glutamine, omega-3 fatty acids, vitamins, and trace minerals, and its use has often been associated with decreased infectious complications and sometimes with improvements in wound healing.Ĭritical Issues: A key to understanding the role of immunonutrition in wound healing is recognizing the distinct contributions and importance of the various elements utilized.įuture Directions: Critical areas for future study include identifying the specific populations, timing, and ideal composition of immunomodulating diets in order to optimize the wound healing process. Recent Advances: Recent studies have rekindled efforts to elucidate the roles of specific immunonutrients, and we now have a better understanding of the conditionally essential role of various nutrients such as arginine, which becomes essential in certain clinical situations such as for the trauma patient or patients at high risk for malnutrition. Still, the prospect of optimizing nutrition to assist the immune system in wound repair bears great significance in both medical and surgical fields, as the costs of wound care and repair cannot be ignored. Although deficiencies in certain nutrients have long been known to impair healing, supplementation of specific immune modulating nutrients has not consistently yielded improvements in wound healing. Significance: The role of immunonutrition in wound healing has been an area of both interest and controversy for many years.
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