Getting a tattoo is a huge decision because they're permanent. Well, not entirely. There are ways to remove ink-based bodily adornments, but they can be painful and complicated. Also, it doesn't help that cells are actually doing all the maintenance work, making it that much harder to get rid of tattoos.

A new study by French scientists, published in the Journal of Experimental Medicine, suggests that the permanence of tattoos is caused by something called macrophages — immune system cells that swallow up foreign debris in the body. Targeting these cells might lead to better tattoo removal procedures.

What Happens When You Get A Tattoo

When a person gets a tattoo, macrophages swallow up the injected ink, the researchers claim, but because perhaps ink granules are too big, they can't fully break them down, so the ink remains.

As time goes by, these macrophages die and release the tattoo granules they swallowed up, which are then eaten by a new army of macrophages, restarting the process — maintaining the tattoo on the body. That's according to Sandrine Henri, a researcher at the Immunology Center of Marseille-Luminy who led the study alongside Bernard Malissen.

"When they die [within a few years], they release into the dermis the pigments they contain. These free pigments are then taken up by the neighboring macrophages, which seem to be the only skin cells capable to handle them," said Henri.

Experts have long held the belief that tattoos stay permanent because they pigment fibroblasts under the skin, which are the cells that synthesize collagen.

In the study, the researchers tattooed green stripe patterns onto the tail of mice, and then weeks later, those same mice received an injection to kill off the macrophages that ate up the green pigment. The macrophages did die — but that tattoo remained. They observed that new macrophages almost immediately began replacing the dead ones.

Better Ways To Remove Tattoos

The researchers say their findings may help other researchers to come up with improved methods for removing tattoos, ones that are far more efficient and less painful for the host.

Among the current removal methods include laser treatment, but this isn't exactly quick. For some, it might take years before the tattoo is completely erased. This is because macrophages are excellent at reabsorbing pigment from nearby cells and keeping them in the dermis instead of being sent for disposal, said the researchers. They hope to work with dermatologists in the future to determine whether purposefully killing off macrophages will speed up the laser process.

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