A new study, published in the journal Proceedings of the Royal Society B: Biological Sciences, has found that humans heal from wounds much more slowly than other primates.
To compare healing speeds, Akiko Matsumoto-Oda from the University of the Ryukyus in Japan and her team studied four types of primates - velvet monkeys, Sykes' monkeys, olive baboons, and chimpanzees.
The researchers made small wounds on these animals, treated them to prevent infection, and measured how quickly they healed. All of the primates healed at about 0.61 millimetres per day.
Then, the team looked at 24 human patients who had surgery to remove skin tumours. Their wounds healed much more slowly, at just 0.25 millimetres per day.
The researchers also checked wound healing in mice and rats, and found they healed at about the same speed as the primates, but much faster than humans, suggesting that most mammals have an optimal healing speed, while humans are the exception.
The team noted that the wound healing happens in several steps in a human. First, blood clots stop the bleeding. Then immune cells clean the wound, and the body starts to rebuild using collagen and new skin cells.
Meanwhile, other animals heal in similar ways, but some, like rats, mice, horses, and cats, can also pull the edges of a wound together, helping it close faster.
The researchers believe that humans may have evolved slower healing after splitting from the common ancestor with chimpanzees about 6 million years ago. They suggest that changes in body hair, skin thickness, and the number of sweat glands may be part of the reason.
As humans lost body hair and gained more sweat glands, the skin may have thickened for protection, which could have slowed healing. However, living in social groups and using medicinal plants might have helped humans manage wounds despite healing more slowly.
"This finding indicates that the slow wound healing observed in humans is not a common characteristic among the primate order and highlights the possibility of evolutionary adaptations in humans," the researchers concluded.
"A more comprehensive understanding of the underlying causes of delayed wound healing in humans requires a comprehensive approach that integrates genetic, cellular, morphological, fossil human skeletal, and extant non-human primate data".
by RTTNews Staff Writer
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