Why Do Wounds Heal Slowly With Age? Researchers Find Long-Sought Answer

Posted: Nov 19 2016, 8:29am CST | by , Updated: Nov 19 2016, 11:09am CST, in News | Latest Science News

 

Why Do Wounds Heal Slowly with Age? Researchers Find Long-Sought Answer
Five days after the injury to young mice, the new skin is filling wound (Top) while it took longer time in "Bottom" image. Credit: Rockefeller University
 

Researchers that disruptions to communication between skin cells and immune cells slow down the healing process

Younger people tend to recover faster. But as we get older, our injuries take longer time to heal. 

In World War I, the injuries of older soldiers healedmuch more slowly than the younger ones. This is where the phenomena was first observed and documented. Yet until now, researchers have not been able to work out the what age-related changes disrupts healing process and slows down recovery.

The ecent experiments on aging mouse skin, however, provide a biological explanation for the phenomena.

“Wound healing is one of the most complex processes to occur in the human body,” said Brice Keyes, researcher at Calico Life Sciences. “Numerous types of cells, molecular pathways and signaling systems go to work over timescales that vary from seconds to months. Changes related to aging have been observed in every step of this process.”

A wound, which could be a result of accident or surgery, requires a sequence of events to take place to heal and both skin cells and immune cells contribute to this process. First the blood platelets clump together to form clots and a scab. Then, immune cells clean up the wound and after that rebuilding of the tissues takes place where new skin cells known as keratinocytes travel in and fill in the wound under the scab.

In the latest study, researchers focused on the letter step in two-month old verses 24-month old mice – which are roughly equivalent to 20 and 70 years old humans. Researchers found that among older mice, keratinocytes were slower to travel from their original place to the wounded skin under the scab. Thus, it took longer to close a gap.

Following an injury, keratinocytes at the wound edge communicate with immune cells known as Skints and ask them to move around and assist in filling gap. But experiments show that this  communication is delayed in the older mice.

“Within days of an injury, skin cells migrate in and close the wound, a process that requires coordination with nearby immune cells. Our experiments have shown that, with aging, disruptions to communication between skin cells and their immune cells slow down this step.” Professor Elaine Fuchs said.

To quicken the communication between skin and immune cells, researchers turned to a protein that reside in immune cells and is released after the injury. When this protein was applied on both young and old skin tissues in petri dish, researcher observed enhanced signaling and migration, which was otherwise relatively slower in the older mice.

Researchers hope the same principle could be applied to develop treatments and approaches that could speed healing among older people.

Fuchs says. “Our work suggests it may be possible to develop drugs to activate pathways that aging skin cells to communicate better with their immune cells neighbor and so boost the signals that normally decline with age.”

The results of the study were published in November 17 issue of Cell.

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Hira Bashir covers daily affairs around the world.

 

 

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