Last updated March 15, 2018 at 10:45 am
Our bodies response to tattoos may hold the key to more effective removal.
Credit: Belyjmishka/iStock
New research, which looked at skin and immune cells in mice, shows that there is a continuous turnover of a type of immune cell called macrophages.
After tattoo ink is implanted in the skin, immune cells are attracted to the wound site. These macrophages start a cycle where they capture pigment, become trapped by the size of the pigment, then die and release it. The cycle then begins again, with a new macrophage taking up the pigment.
Prior to this research, it was thought that either macrophages or dermis cells permanently trapped the pigment.
Evidence from mice models
The researchers discovered this by experimenting on tattooed mice that had been genetically engineered to allow them to kill off all of the affected macrophages at once.
They also transferred tattooed skin from one mouse to another, which showed them that the recipient animal’s immune system kicked in to supply the macrophages that kept the process going.
Green tattoo pigment is taken up by dermal macrophages (left). The pigment is released when these cells are killed (center) but, 90 days later, is taken back up into new macrophages that have replaced the old ones (right). CREDIT: Baranska et al., 2018
“We think that, when tattoo pigment-laden macrophages die during the course of adult life, neighbouring macrophages recapture the released pigments.” says co-lead researcher Sandrine Henri. This accounts for their long-term persistence, she says.
These finding could be applied to current and future methods of laser removal surgeries, says co-lead research Bernard Malissen.
“Tattoo removal can be likely improved by combining laser surgery with the transient ablation of the macrophages present in the tattoo area.
As a result, the fragmented pigment particles generated using laser pulses will not be immediately recaptured, a condition increasing the probability of having them drained away via the lymphatic vessels.”
This research was published in the Journal of Experimental Medicine.
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