Health

No smoking four weeks before operation cuts risks: WHO

Patients who stop smoking at least four weeks before an operation significantly reduce the risk of having postsurgical complications because their blood flow improves, according to a study published Monday.

Medical research

How signalling proteins affect wound healing

What do a scraped knee, a paper cut, or any form of surgery have in common? The short answer is a wound in need of healing—but the long answer lies in a series of biological activities that allow tissues to repair themselves.

Medical research

Linking wound healing and cancer risk

When our skin is damaged, a whole set of biological processes springs into action to heal the wound. Now, researchers from the VIB-UGent Center for Inflammation Research have shown that one of the molecules involved in this, ...

Cardiology

New molecule could help improve heart attack recovery

Reparative medicine scientists at the Fralin Biomedical Research Institute discovered a new compound that could shield heart tissue before a heart attack, as well as preserve healthy cells when administered after a heart ...

Medical research

Scars: Gone with the foam

A scar on the elbow that is strained with every movement, or a foot, on which a wound simply does not want to close—poorly healing injuries are a common cause of health restrictions. And although millions of people are ...

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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