Despite constant skin renewal Why a tattoo does not fade

New findings: That's why tattoos do not fade

Around 15 percent of Germans have a tattoo. Many a person would rather not have it, but the tattoo remains - even though the skin is constantly renewed. Researchers have now discovered why tattoos do not fade.

Tattoos do not disappear despite skin renewal

While tattoos used to be socially outlawed and reserved for special populations (such as seafarers, prisoners), today they are widely accepted and found in all walks of life. Some want to get rid of the pictures or writing on the skin. It is a pity that the tattoos do not just disappear again, even though the skin is constantly renewing itself. Researchers have now found out why the colors are preserved.

Although the skin is constantly renewed, tattoos are preserved. Researchers have now discovered why tattoos do not fade. (Image: K.- P. Adler / fotolia.com)

Remove old youthful sins

Sometimes it is a small rose on the arm, sometimes a dolphin on the back; but it can also be the name of the ex or an ugly "antlers": Many people have stung a tattoo that they want to get rid of again.

But what possibilities exist to have the body images removed?

Laser removal is sometimes associated with major health risks. Nevertheless, it is considered the safest and most effective method.

But why is it so problematic to remove tattoos? After all, the skin is constantly renewing itself. Researchers from France have now found an answer.

Color particles deposit in macrophages

When tattooing water-insoluble color pigments are stung in the skin. In the past, it was assumed that the tattoo remains permanently because the ink colors connective tissue cells.

However, French scientists have now been able to show in mice that the color particles in phagocytes - called macrophages - deposit.

When these cells die off, the pigments are initially released, but only until they are resumed by new macrophages.

As the researchers from the Aix Marseille Université report in the journal "Journal of Experimental Medicine", the particles in this process remain largely in their original position, so that the tattoo does not change noticeable.

Tails tattooed by mice

To get to their results, the researchers tattooed the tails of mice. The animals were genetically engineered so that the skin macrophages could be selectively destroyed by the administration of a toxin.

The scientists examined sections of the tattooed skin under a microscope to confirm that the ink particles were actually taken up by the macrophages.

They then infected the rodents with diphtheria, causing macrophages to be destroyed. A few weeks later, new blood-infested macrophages had replaced the destroyed cells. The tattoo remained unchanged.

Better removal of tattoos

"The fact that macrophages hardly move in the skin, explains why the tattoo is quite stable," said study author Sandrine Henri, according to a report by the journal "Scientific American".

"In addition, the pigment particles present in the tattoo ink are quite large and, because of their size, do not flow via the lymphatic vessels into the lymph nodes. Once released from dying macrophages, they remain stuck until they are taken up by other macrophages, "said the researcher.

Simon Yona, an immunologist at University College London, who studied macrophages and was not involved in the study, praised the work of the French scientists.

It "actually provides a strategy to remove unwanted tattoos, in combination with conventional approaches that could be particularly useful for removing small tattoos in a well-defined location."

Henri said that she and her colleagues are already developing a method to provide certain types of immune cells with genetic instructions, and that they plan to work closely with dermatologists in the next stages of their work.

She hopes that laser tattoo removal could work better when combined with the temporary inhibition of skin macrophage function. (Ad)