Wounds on the skin are elderly people with fewer scars than with the young, and now it became clear why. The reason for this phenomenon – the lack of blood protein SDF1 with age is synthesized in much smaller amounts.
To such conclusion scientists from the medical school of the University of Pennsylvania in Philadelphia, conducted a study on mice and samples of human skin, grown in laboratory conditions, according to the website of the University.
– Dermatologists and plastic surgeons are constantly observed that wounds of the elderly heal with a thinner scar than in younger patients, but until now nobody could answer the question why this is so, says the lead author of the scientific work, doctor of medical Sciences Thomas Leung (Thomas Leung).
He and his team were engaged in that studied the healing of tissues in mice of different ages, in terms of human measurements – 12 and 70 years. Animals did the piercings in the ears, and in older specimens they heal without scarring, and young people – with the scars. The researchers then literally exchanged blood in animals, and then the effect was reversed: the ears of young mice healed without scars.
Then the scientists took tissue samples from young and old mice and compared the expression of different genes in them. They identified 80 differences, explore all the given possible combinations was an impossible task. But as previously became apparent that the reason for the different efficiency of the regenerative function of the skin is covered in blood, the circle of “suspects” is narrowed to 13. One of them was SDF1 protein in young mice, which it was already known that he plays a role in the formation of scars on the skin, liver and lungs.
To confirm their guesses scientists have created a genetically modified mouse, which was not SDF1 in the skin, as a result, her recovery was going the same way as in older animals.
– This is a rare case where aging actually improves the body’s ability to heal, instead of reducing it, – said Thomas Leung. – When we are younger, we have allocated more than SDF1 in the bloodstream to form scars, but with aging we lose this ability, which allows the tissue to recover.
The meaning of this process from the point of view of evolution is that tissue regeneration is a slow process, requiring in mice about a month on the full restoration of the skin in comparison with 3-5 days in the formation of scars. Young and active people the second option is more advantageous because it allows faster return to duty.
Note that experiments on human skin grown in the laboratory, also showed that its recovery depends on the availability of SDF1 protein.