Medical research

Hair follicles heal blisters at personal cost

A team of scientists has shown that the healing of skin blisters is driven by hair follicle stem cells, which delay their own development in the process.

Cardiology

Self-organizing human heart organoids

Biologist Sasha Mendjan at the Austrian Academy of Sciences in Vienna and his team have used human pluripotent stem cells to grow sesame-seed-sized heart models, called cardioids, that spontaneously self-organize to develop ...

Cardiology

Newly discovered immune cell function vital to healing

Cardiovascular disease, the most common cause of death, is the result of oxygen deprivation as blood perfusion to affected tissue is prevented. To halt the development of the disease and to promote healing, re-establishment ...

Biomedical technology

Seaweed molecules found to aid wound healing

Scientists from the ARC Centre of Excellence for Electromaterial Science (ACES) and University of Wollongong (UOW), in partnership with their seaweed bioinks collaborators Venus Shell Systems, have discovered that a molecular ...

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. ...

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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