Ironically, researchers have just discovered that a tissue-damaging disease somehow has the potential to regenerate mammalian livers.
Leprosy, one of mankind’s oldest and most persistent diseases, is caused by two parasitic bacteria, Mycobacterium leprae Where Mycobacterium lepromatosis. These microbes damage the skin, nerves and other tissues when infected.
Unlike the the stigma that surrounds it, leprosy is not very contagious. It is spread by repeated and excessive contact with an infected person’s mucus; however, 95% of people exposed to the bacteria do not contract the disease, and it can be cured with a cocktail of modern drugs.
Bacteria are naturally present in armadillos (Dasypus novemcinctus), and by studying the interaction between the microbe and its host, the researchers noticed that the parasite had an unexpected ability to hijack and reprogram cells.
For example, University of Edinburgh medical researcher Samuel Hess and his colleagues infected 45 armadillos with M. leprae13 of which resisted infection, then they compared the infected livers to a group of 12 uninfected animals.
Surprisingly, the infected armadillos developed more livers – their organs became perfectly oversized. The organs remained functionally normal with all the right types of liver tissue in the right places, including the proportionally enlarged blood and biliary systems.
“If we can identify how bacteria develop the liver as a functional organ without causing adverse effects in living animals, we may be able to translate this knowledge to develop safer therapeutic interventions to rejuvenate aging livers and regenerate damaged tissues, Explain Anura Rambukkana, cell biologist at the University of Edinburgh.
It seems that over the course of evolutionary history, bacteria have learned to regenerate and increase the number of cells that suit them best in the body of the armadillo where they live.
Although the details are unclear, M. leprae appears to reprogram adult liver cells, hepatocytes, converting them into a stem cell-like state, allowing all additional liver tissue to grow properly from them.
Research team members previously demonstrated leprosy could do something similar to nerve support cells called Schwann cells, reprogramming them into a younger cellular state that can produce a wider variety of cell types.
In the latest armadillo studythis resulted in a perfectly healthy oversized liver with no signs of scarring, aging, fibrosis or tumor.
“Thus, regenerative medicine’s pursuit of a functional organ ‘grown to order’ is not theoretical but has natural precedent,” Hess and colleagues write.
While human livers have the ability to regrow at least in part – the only internal organ that can do so – even with repeated inflammatory damage from chronic liver disease, they accumulate damage over time, leaving millions of people succumb to chronic liver disease every year.
Understanding how leprosy parasites regenerate liver tissue may one day give us the power to harness this ability as well.
“Although unexpected and unconventional, this evolutionary refinement live [within body] model can advance our understanding of native regenerative machinery,” the team concluded. in their diary.
This research was published in Medicine Reports Unit.