Health

Why do older people heal more slowly?

I recently visited an 83-year-old patient in the hospital after EMTs rushed her to the ER with an infected leg wound. Her ordeal started inconspicuously when she bumped into the sharp edge of a table and developed a small ...

Biomedical technology

Researchers develop 3-D dressing to heal wounds

Researchers at ITMO University and the University of Toronto have developed a material based on gelatin and nanocrystalline cellulose that can fight off antibiotic-resistant bacteria and speed up the wound healing process. ...

Medical research

Researchers study delayed wound healing due to gene mutations

"Wound healing is one of the most complex biological processes," write Professor Kazumitsu Sugiura and Dr. Kenta Saito from Fujita Health University, Japan, in their article recently published in Scientific Reports. As countless ...

Medical research

A new approach to understanding the biology of wound healing

Our bodies frequently heal wounds, like a cut or a scrape, on their own. However patients with diabetes, vascular disease, and skin disorders, sometimes have difficulty healing. This can lead to chronic wounds, which can ...

Immunology

Rare immune cells drive gut repair

Scientists from King's College London have discovered an unexpected tissue reparative role for a rare immune cell type in the gut that could tip toward fibrosis or cancer if dysregulated. The breakthrough will have important ...

Medical research

Novel alkaline hydrogel advances skin wound care

With an increase in the elderly and aging population and also in the number of invasive surgeries, wound healing has become a critical focus area in medicine. The complex bodily processes involved in wound healing make it ...

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Wound healing

Wound healing, or wound repair, is an intricate process in which the skin (or some other organ) repairs itself after injury. In normal skin, the epidermis (outermost layer) and dermis (inner or deeper layer) exists in a steady-stated equilibrium, forming a protective barrier against the external environment. Once the protective barrier is broken, the normal (physiologic) process of wound healing is immediately set in motion. The classic model of wound healing is divided into three or four sequential, yet overlapping, phases: (1) hemostasis (not considered a phase by some authors), (2) inflammatory, (3) proliferative and (4) remodeling.

Upon injury to the skin, a set of complex biochemical events takes place in a closely orchestrated cascade to repair the damage. Within minutes post-injury, platelets (thrombocytes) aggregate at the injury site to form a fibrin clot. This clot acts to control active bleeding (hemostasis).

In the inflammatory phase, bacteria and debris are phagocytized and removed, and factors are released that cause the migration and division of cells involved in the proliferative phase.

The proliferative phase is characterized by angiogenesis, collagen deposition, granulation tissue formation, epithelialization, and wound contraction. In angiogenesis, new blood vessels are formed by vascular endothelial cells. In fibroplasia and granulation tissue formation, fibroblasts grow and form a new, provisional extracellular matrix (ECM) by excreting collagen and fibronectin. Concurrently, re-epithelialization of the epidermis occurs, in which epithelial cells proliferate and 'crawl' atop the wound bed, providing cover for the new tissue.

In contraction, the wound is made smaller by the action of myofibroblasts, which establish a grip on the wound edges and contract themselves using a mechanism similar to that in smooth muscle cells. When the cells' roles are close to complete, unneeded cells undergo apoptosis.

In the maturation and remodeling phase, collagen is remodeled and realigned along tension lines and cells that are no longer needed are removed by apoptosis.

However, this process is not only complex but fragile, and susceptible to interruption or failure leading to the formation of chronic non-healing wounds. Factors which may contribute to this include diabetes, venous or arterial disease, old age, and infection.

This text uses material from Wikipedia, licensed under CC BY-SA