Improved skin regeneration with acellular fish skin grafts

Advances in our understanding of the mechanisms that bring about the resolution of acute inflammation have uncovered a new genus of pro-resolving lipid mediators that include the lipoxin, resolvin, protectin and maresin families, collectively called specialized pro-resolving mediators. Synthetic versions of these mediators have potent bioactions when administered in vivo. In animal experiments, the mediators evoke anti-inflammatory and novel pro-resolving mechanisms, and enhance microbial clearance. Although they have been identified in inflammation resolution, specialized pro-resolving mediators are conserved structures that also function in host defence, pain, organ protection and tissue remodelling. This Review covers the mechanisms of specialized pro-resolving mediators and omega-3 essential fatty acid pathways that could help us to understand their physiological functions.

Significance: Chronic wounds include, but are not limited, to diabetic foot ulcers, venous leg ulcers, and pressure ulcers. They are a challenge to wound care professionals and consume a great deal of healthcare resources around the globe. This review discusses the pathophysiology of complex chronic wounds and the means and modalities currently available to achieve healing in such patients. Recent Advances: Although often difficult to treat, an understanding of the underlying pathophysiology and specific attention toward managing these perturbations can often lead to successful healing. Critical Issues: Overcoming the factors that contribute to delayed healing are key components of a comprehensive approach to wound care and present the primary challenges to the treatment of chronic wounds. When wounds fail to achieve sufficient healing after 4 weeks of standard care, reassessment of underlying pathology and consideration of the need for advanced therapeutic agents should be undertaken. However, selection of an appropriate therapy is often not evidence based. Future Directions: Basic tenets of care need to be routinely followed, and a systematic evaluation of patients and their wounds will also facilitate appropriate care. Underlying pathologies, which result in the failure of these wounds to heal, differ among various types of chronic wounds. A better understanding of the differences between various types of chronic wounds at the molecular and cellular levels should improve our treatment approaches, leading to better healing rates, and facilitate the development of new more effective therapies. More evidence for the efficacy of current and future advanced wound therapies is required for their appropriate use.

Optimum healing of a cutaneous wound requires a well-orchestrated integration of the complex biological and molecular events of cell migration and proliferation, and of extracellular matrix deposition and remodelling. Cellular responses to inflammatory mediators, growth factors, and cytokines, and to mechanical forces, must be appropriate and precise. However, this orderly progression of the healing process is impaired in chronic wounds, including those due to diabetes. Several pathogenic abnormalities, ranging from disease-specific intrinsic flaws in blood supply, angiogenesis, and matrix turnover to extrinsic factors due to infection and continued trauma, contribute to failure to heal. Yet, despite these obstacles, there is increasing cause for optimism in the treatment of diabetic and other chronic wounds. Enhanced understanding and correction of pathogenic factors, combined with stricter adherence to standards of care and with technological breakthroughs in biological agents, is giving new hope to the problem of impaired healing.