This axolotl, which looks almost mischievously, is an important aid to medicine. Because its cells and tissues provided crucial clues as to why this salamander can replace entire limbs, but we cannot
The axolotls native to Mexico are evolutionary eccentrics in many ways. Unlike other salamanders, their gill-bearing and aquatic larvae never transform into land-living amphibians. Instead, the axolotl become sexually mature as larvae and never lose their larval-typical features throughout their life – including the gill tufts on the head sides that are clearly recognizable in this picture. Among other things, these appendices gave these salamanders their name: Axolotl means something like water monster in the Aztec language Nahuatl.
But the axolotl is mainly famous for one other property: it has an unusually good ability to regenerate. If a leg is severed, a nerve is severed or an organ is injured, these body parts simply grow back. Even parts of the brain or heart can regenerate the “healing miracle”. Special genetics seem to be responsible for this, by means of which a kind of “regeneration brake” of the cells and tissues is released. As a result, cell types that are normally difficult to regrow, such as nerves, can regenerate in these animals
But there is also another factor, as researchers led by James Godwin from the MDI Biological Laboratory in the US state of Maine have found out with the help of the axolotl shown here, among other things. Accordingly, the macrophages of the immune system also play a decisive role in the axolotl’s ability to heal. The axolotl-specific type of these phagocytes prevents the tissue from scarring at the wound site and instead promotes regeneration.
Goodwin and his team recently discovered that these special macrophages do not come from the bone marrow, as is usually the case, but have their origin in the liver of the axolotl. This finding now opens up the possibility of investigating whether this special cell type might not also exist in humans and what distinguishes our macrophages from those of the axolotl. “Humans could also have macrophages that could heal injuries, but something might be holding back,” says Goodwin.
The aim of such research is not to allow people to regrow an entire leg. Instead, the axolotl researchers want to improve the healing of injuries – for example, by preventing scarring. The possibility of stimulating severed or severely injured nerves to regenerate also drives this research.