Researchers in France have discovered that, though a tattoo may be forever, the skin cells that carry the tattoo pigment are not. Instead, the researchers say, the cells can pass on the pigment to new cells when they die. The study, which will be published March 6 in the Journal of Experimental Medicine, suggests ways to improve the ability of laser surgery to remove unwanted tattoos.
For many years, tattoos were thought to work by staining fibroblast cells in the dermal layer of the skin. More recently, however, researchers have suggested that macrophages--specialized immune cells that reside in the dermis--are attracted to the wound inflicted by the tattoo needle and gobble up the tattoo pigment just as they would normally engulf an invading pathogen or piece of a dying cell. In either case, it is assumed that the pigment-carrying cell lives forever, allowing the tattoo to be more or less permanent.
Green tattoo pigment is taken up by dermal macrophages (left). The pigment is released when these cells are killed (center) but, 90 days later, is taken back up into new macrophages that have replaced the old ones (right).
Credit: Baranska et al., 2018
Usage Restrictions: Reporters may freely use these materials in news coverage with the appropriate credit information.
A team of researchers led by Sandrine Henri and Bernard Malissen of the Centre d'Immunologie de Marseille-Luminy developed a genetically engineered mouse that allowed them to kill the macrophages that reside in the dermis and certain other tissues. Over the following few weeks, these cells are replaced by new macrophages derived from precursor cells known as monocytes.
The researchers found that dermal macrophages were the only cell type to take up pigment when they tattooed the mice's tails. Yet the tattoos' appearance did not change when the macrophages were killed off. The team determined that the dead macrophages release the pigment into their surroundings, where, over the following weeks, it is taken up by new, monocyte-derived macrophages before it can disperse.
This cycle of pigment capture, release, and recapture occurs continuously in tattooed skin, even when macrophages aren't killed off in a single burst. The researchers transferred a piece of tattooed skin from one mouse to another and found that, after six weeks, most of the pigment-carrying macrophages were derived from the recipient, rather than the donor, animal.
"We think that, when tattoo pigment-laden macrophages die during the course of adult life, neighboring macrophages recapture the released pigments and insure in a dynamic manner the stable appearance and long-term persistence of tattoos," Henri explains.
Tattoos can be removed by laser pulses that cause skin cells to die and release their pigment, which can then be transported away from the skin and into the body's lymphatic system.
"Tattoo removal can be likely improved by combining laser surgery with the transient ablation of the macrophages present in the tattoo area," says Malissen. "As a result, the fragmented pigment particles generated using laser pulses will not be immediately recaptured, a condition increasing the probability of having them drained away via the lymphatic vessels."
Baranska et al., 2018. J. Exp. Med. http://jem.
About the Journal of Experimental Medicine
The Journal of Experimental Medicine (JEM) features peer-reviewed research on immunology, cancer biology, stem cell biology, microbial pathogenesis, vascular biology, and neurobiology. All editorial decisions are made by research-active scientists in conjunction with in-house scientific editors. JEM provides free online access to many article types from the date of publication and to all archival content. Established in 1896, JEM is published by Rockefeller University Press. For more information, visit jem.org.
Visit our Newsroom, and sign up for a weekly preview of articles to be published. Embargoed media alerts are for journalists only.
Ben Short | EurekAlert!
Skipping Meat on Occasion May Protect Against Type 2 Diabetes
25.06.2019 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke
Inhaling air pollution-like irritant alters defensive heart-lung reflex for hypertension
19.06.2019 | University of South Florida (USF Innovation)
From June 25th to 27th 2019, the Fraunhofer Institute for Digital Media Technology IDMT in Ilmenau (Germany) will be presenting a new solution for acoustic quality inspection allowing contact-free, non-destructive testing of manufactured parts and components. The method which has reached Technology Readiness Level 6 already, is currently being successfully tested in practical use together with a number of industrial partners.
Reducing machine downtime, manufacturing defects, and excessive scrap
The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.
Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...
The well-known representation of chemical elements is just one example of how objects can be arranged and classified
The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...
Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.
Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...
Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.
The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...
24.06.2019 | Event News
29.04.2019 | Event News
17.04.2019 | Event News
25.06.2019 | Architecture and Construction
25.06.2019 | Life Sciences
25.06.2019 | Power and Electrical Engineering