For many years it was believed that The tatoos stained cells in the dermis of the skin (called fibroblasts). But researchers recently suggested that the skin’s macrophages (specialized immune cells residing in the dermis) “engulf” the pigment from the tattoo, as they normally would with an invading pathogen or a piece of dying cell.
In both cases, it was assumed that the pigment-carrying cell lived forever, thus allowing the tattoo to be more or less permanent.
Macrophages pass on the pigment before they die
This hypothesis has just been questioned 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 macrophages residing in its dermis.
Over the weeks, the researchers observed that the cells thus destroyed were replaced by new macrophages derived from precursor cells found in the blood and known as monocytes. They discovered that macrophages in the dermis were the only type of cells that absorbed 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 macrophages pass this pigment on to new cells before they die. This cycle of pigment capture, release and reuptake occurs continuously in tattooed skin, even when macrophages are not killed all at once. Understanding this cycle suggests that tattoos could be erased by laser pulses which would cause skin cells to die and their pigments to release and fragment.
“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
