Those cells and the pigment inside them can hang around for years. Together, the macrophages and fibroblasts bind enough ink for the image of, say, a carrot or feather to appear on your calf.
Hold the line tattoo full#
"They just sit there like a full vacuum cleaner bag," says Klitzman.Īnother type of cell, called a fibroblast, is also known to take in some ink particles in human skin. Eventually, the pigment-filled macrophages dial back their attack, content to contain the threat, even if they can't completely neutralize it. That means a macrophage that has gorged on ink has no way to finish its job. Acid has little effect on the ink ingredients. It's a good strategy for killing bacteria and viruses, but not for tattoo pigments. Usually, a macrophage digests the invaders it devours, using acid to rip its enemy apart. "Macrophages can basically swallow many, many tattoo pigment particles, almost like a vacuum cleaner, just go along and suck up all those particles," he says. They're specialized immune cells - their name means big eater in Greek - and their job is to slurp up interlopers, says Klitzman. That's where the macrophages, the cells Henri studied, come in. For the remaining pigment particles, the next order of the immune system's business is consuming the foreign invaders, to try to destroy them.
Hold the line tattoo skin#
Newly tattooed skin swells, the same way it would respond to any other wound, and blood and lymph ferry away the smallest bits of ink. Only a fraction of the ink an artist lays down actually makes it into the dermis, and this is also why new tattoos tend to leak ink as they heal. So skin cells mount a multilevel attack on the ink particles.įirst, the cells that weren't hit by the tattoo needle block out guests, Klitzman says.
In broad strokes, we understand this process, says Bruce Klitzman, a biomedical engineer at Duke who once worked on creating an erasable tattoo.Īs a tattoo artist outlines a yin-yang symbol on someone's shoulder, a solid needle loaded with ink pierces the tattoo-ee's skin, or epidermis, and the needle's exit lets pigment flow into a second layer of skin, the dermis, Klitzman says.īut any self-respecting immune system treats all visitors - including the ink particles meant to create a wolf's face on your forearm - as unwelcome. To think about removing ink from human shoulders, rather than mouse tails, it helps to know how tattoos appear. The researchers' findings appeared Tuesday in the Journal of Experimental Medicine. It turns out that new macrophages quickly took over the job of holding the tiny flecks of ink in place, and the mice kept their sporty green-striped tails.īut if it were possible, Henri says, to use an ointment, or a drug, to delay those replacement macrophages, it might improve tattoo removal for mice - and humans. The messed-up macrophages released their ink particles, but the color persisted. So they engineered mice whose macrophages - and only those cells - would shrivel in the face of a specific toxin, and then injected that compound into these special, tattooed mice. The researchers thought they might be able to disrupt the tattoos by destroying the macrophages that had locked up the ink. From the mice's tail tattoos, Henri and her colleagues identified one type of cell that captured ink particles and stayed in place, the dermal macrophage. If you zoom way in on any tattoo, it's really just a bunch of cells holding tight to ink particles. "The thing is, the mouse skin can be super fragile, much more fragile than human skin," says Sandrine Henri, an immunologist at the Centre d'Immunologie Marseille-Luminy.
Instead, they got tail tats - three stripes of green ink - for researchers to study. The mice didn't get Mom tattoos on their tiny biceps. So, first, of course, they gave some mice tattoos. Recently, a group of French scientists looked into how that works, hoping to use the knowledge to improve tattoo removal. Between the lines, he seemed to say, "This will be permanent, so I don't want to give you the wrong tattoo."īut considering how many changes skin weathers - burns heal, scars fade and wrinkles set in - it's sort of unbelievable that tattoos do stick around. Maybe they should set up an appointment for her sometime next week, with another artist, he offered. The artist rubbed his beard and told her he didn't do realistic tattoos. have a photo on my phone of the feather that I like, I could show you that?"
He peppered her with questions: How big? What style? She alternated between a blank stare and a furrowed brow: "I. "I want a red-tailed hawk feather," she told the artist on duty at the Washington, D.C., tattoo parlor. Last Saturday, while I was visiting Fatty's Tattoos and Piercings, a college-aged woman in a hoodie walked in and asked for a tattoo, her first, right on the spot. Make sure that tattoo is one you want to keep.