Recently, European scientists bombarded tattooed corpses with X-rays from a particle accelerator. While it could have been a scene for an upcoming goth body horror movie, it was actually a study meant to benefit living humans with tattoos. This grisly experiment helped European nanoparticle researchers understand how tattoo ink travels in human bodies over time.
In a study published in the journal Scientific Reports on Tuesday, a team of French and German researchers reports that nanoparticles found in some tattoo inks can migrate away from the skin — and accumulate in lymph nodes.
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This team, made up of members from the European Synchrotron Radiation Facility in France, and the German Federal Institute for Risk Assessment, Physikalisch-Technische Bundesanstalt, and Ludwig-Maximilians University, used synchrotron X-ray fluorescence to detect the moving pigment particles in the corpses.
First, the scientists took samples of lymph nodes and skin from four tattooed donor cadavers and one un-tattooed control cadaver. Then, they examined the skin and lymph nodes to see whether the pigments present in the skin were also in the lymph nodes. If that were the case, it would suggest that particles in the ink had indeed migrated through the lymphatic system to the lymph nodes, which filter lymph, the fluid that carries white blood cells through the body to fight infections.
Sure enough, they did find particles in the nodes, confirming their long-held suspicion that pigment particles accumulate there.
“We found a broad range of tattoo pigment particles with up to several micrometers in size in human skin but only smaller (nano)particles transported to the lymph nodes,” write the study’s authors. They suspect that the larger particles — those up to a micrometer across — can’t travel through the lymphatic system. Which is a good thing, because they found that just the small particles had caused the tattooed donors’ lymph nodes to become enlarged.
In particular, the researchers found elevated levels of titanium dioxide — a white tattoo ink pigment that’s added to other pigments to create various color shades — in the skin and lymph nodes of tattooed donors but not in the control sample.
Unsettling as it may be for people with tattoos to learn that their ink isn’t staying put, it’s actually not that surprising that tattoo pigment particles can be found in the lymphatic system. When foreign matter like tattoo ink is traumatically inserted into the body, this system’s action kicks into high gear in its attempt to expel invaders.
Until now, this kind of research had been challenging to conduct. The scientists needed to test actual biological tissues, but that presented a dilemma.
“The animal experiments which would be necessary to address these toxicological issues were rated unethical because tattoos are applied as a matter of choice and lack medical necessity, similar to cosmetics,” the study’s authors write.
Admittedly, this is a small sample size, so these findings are far from being the final word on the matter, and this paper definitely doesn’t support some advocates’ argument that tattoo ink can cause cancer. But it does confirm that tattoo pigments can both travel in the body and accumulate in lymph nodes, which could be worrisome.
“In future experiments we will also look into the pigment and heavy metal burden of other, more distant internal organs and tissues in order to track any possible biodistribution of tattoo ink ingredients throughout the body,” write the authors.
If you liked this article, check out this video on how tattoos are more likely to attract men than women.
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