Engineering Wound Healing Research Articles

Management Of Leg Ulcers

In the United States, leg ulcers present a significant clinical problem, occurring at a rate of approximately 600,000 new cases per year. (1) The most common types are venous, arterial, and neuropathic ulcers. Venous hypertension is the primary culprit in venous ulcerations. Peripheral vascular disease due to atherosclerosis with microvascular or macrovascular changes leads to ischemic ulcers. Sensory impairment with loss of protective sensation in the foot and repetitive trauma lead to neuropathic ulcers. Unusual causes of leg ulcers must be considered in the differential diagnosis. To arrive at the diagnosis, the clinician must perform a thorough history and physical examination, and order relevant investigative studies. Good management of chronic leg ulcers depends on correction of identified underlying conditions, long-term multidisciplinary care effort, and integrating traditional and new wound-healing technologies. Most patients with chronic leg ulcers benefit from the use of compression bandaging at a level appropriate to their vascular status. Venous ulcers must be managed with an arsenal of strategies to control venous insufficiency, heal the wound, and prevent recurrence. Surgery with revascularization remains the treatment of choice for chronic ischemic leg ulcers. In the absence of vascular compromise, up to 90 percent of neuropathic ulcers will heal with proper ulcer debridement, treatment of infection, saline wet-to-dry dressings, and relief of weight from the ulcerated area. The available armamentarium for wound care includes over 2000 wound dressing products and elastic compression wraps. Chronic leg ulcer treatment options have been expanded by alternatives available to treating these wounds. These alternatives include hyperbaric oxygen therapy, bioengineered skin substitutes, recombinant platelet-derived growth factors and vacuum assisted wound closure. Patients with large leg ulcers may benefit from skin grafting. Other patients may benefit from ligation and stripping of superficial veins or subfascial interruption of perforating veins.

Advances in wound care and healing technology.

Wounds are unique in so far as no disease process other than wounds would have existed from the beginning of mankind. Over the years, the management of wounds, especially that of chronic wounds, has had enormous social and economic implications worldwide. With an aging population, this impact is likely to increase. In recent years, this has been reflected by the birth and rapid growth of the new speciality of 'wound healing'. Continuous advances made in the study of the wound microenvironment, an ever-broadening understanding of the pathophysiology of wounds, and improved techniques in monitoring the response of healing have led to continuing developments in the treatment of chronic wounds. Current research focuses on growth factors and human skin substitutes that provide promising results. This article reviews advances made in wound care management over the years. Despite all these advances, it must be borne in mind that basic principles of wound care in a multidisciplinary team setting still remain the backbone of wound management.

Fibrin Microbeads (FMB) as Biodegradable Carriers for Culturing Cells and for Accelerating Wound Healing

We have developed biodegradable fibrin-derived microbeads as potent cell carriers. The fibrin-derived microbeads, 50-200 microm in diameter, were tested for their attachment to a wide range of cell types. Fibrin-derived microbeads were shown to be greatly haptotactic to cells (such as endothelial cells, smooth muscle cells and fibroblasts), which respond to fibrinogen in contrast to keratinocytes and different cell lines derived from leukocytic lineage. The cells on fibrin-derived microbeads could be maintained for more than 10 d and achieved a high density. 31P-nuclear magnetic resonance was employed to monitor phosphate metabolism in cells, with densities on the order of 100 million cells per g of fibrin-derived microbeads. The 31P-nuclear magnetic resonance adenosine triphosphate and phosphocreatine signals, equivalent to the signal obtained with perfused normal skin, indicated that metabolism of cells on fibrin-derived microbeads was responsive to oxygenation and nutrients. Light, fluorescent, and confocal laser microscopy revealed that the porous fibrin-derived microbeads accommodate up to 200-300 cells due to their high surface area which minimized contact inhibition. Cells could degrade the fibrin-derived microbeads and be transferred to seed culture flasks without trypsinization. In a pig skin wound healing model, fibrin-derived microbeads + fibroblasts were transplanted into full thickness punch wounds. This procedure was compared with other treatment modalities, such as the addition of human platelet-derived growth factor BB or fibrin-derived microbeads alone. By the third day after wounding, only the wounds in which fibroblasts on fibrin-derived microbeads were added showed significant formation of granulation tissue. Based on the above, we project many uses of our novel fibrin-derived microbead technology for cell culturing, wound healing and tissue engineering.

A novel treatment for venous leg ulcers

Venous ulceration, a relatively common manifestation of venous hypertension, is often difficult to treat. This article reports the authors' experience with a new wound-healing technology using a bilayered, culture-derived human skin equivalent (HSE, Apligraf) for treatment of venous ulcers. In the patients studied, HSE appeared to promote wound healing in three ways: 1) apparent graft "take"; 2) temporary wound closure (persistence of HSE with subsequent wound re-epithelialization from wound margins); and 3) stimulation of host healing without temporary persistence by acting as a biologic dressing. The demonstrated efficacy of HSE suggests that it will prove useful for promoting the healing of venous ulcers.

Wound Care Dressings

Significant advances in wound healing technologies dramatically enhance the health provider's ability to achieve optimal wound healing. Maximal success in treating both pressure and skin ulcers, however, remains with the fundamental principles of moist wound healing, pressure relief, local and systemic infection control and adequate nutrition. Nurse executives are challenged to evaluate wound dressing technologies in the integrated clinical environment of comprehensive, scientifically validated, wound care clinical practice guidelines.