For many years it was believed that The tatoos stain cells in the dermis of the skin (called fibroblasts). But researchers have recently suggested that skin macrophages (specialized immune cells residing in the dermis) “gobble up” the tattoo pigment, as they normally would an invading pathogen or a piece of dying cell.
In either case, it was assumed that the pigment-bearing cell lived on forever, thus allowing the tattoo to be more or less permanently.
Macrophages pass on pigment before they die
This hypothesis has just been called into question by a research team bringing together researchers from Inserm, CNRS and the University of Aix-Marseille, who have developed a genetically modified mouse capable of killing the macrophages residing in its dermis.
Over the weeks, the researchers observed that the cells thus destroyed had been replaced by new macrophages derived from precursor cells present in the blood and known as monocytes. They discovered that macrophages in the dermis were the only type of cells to absorb the pigment when tattooing the tails of mice.
Read also : A tattoo that changes color depending on the state of health
The team therefore concluded that the macrophages pass this pigment on to new cells before dying. This cycle of capture, release and re-uptake of pigment occurs continuously in tattooed skin, even when the macrophages are not killed all at once. Understanding this cycle suggests that tattoos could be erased by laser pulses that would cause skin cells to die and release and fragment their pigments.
“The fragmented particles of pigment generated by means of the laser pulses would not be immediately recaptured: this state would increase the probability of seeing them evacuated by the lymphatic vessels”.
This study was published in the Journal of Experimental Medicine.
Read also :
Tattoos: a dedicated consultation at Bichat Hospital
Everything you need to know before getting a tattoo