Leprosy bacteria cause liver to grow – wissenschaft.de

Leprosy can cause severe skin changes, paralysis and neurological damage. Bacteria that cause disease may also have medically useful properties: their ability to genetically reprogram host cells could help regenerate the liver. Using armadillos, the researchers demonstrated that the livers of individuals infected with leprosy grew while maintaining their healthy structure. Further insight into the bacteria’s tricks could help develop regenerative therapies for people with liver damage.

Leprosy is one of the oldest known diseases in the world. Also known as leprosy, it was widespread in Europe in the Middle Ages. Today it is mainly found in countries such as India, Brazil and Indonesia. The cause of this infectious disease is Mycobacterium lepra. It spreads mainly under poor hygienic conditions, but it can be effectively combated by timely treatment with antibiotics. However, if left untreated, it burrows into infected host cells and changes them. In advanced stages, it leads to stigmatizing skin tumors, tactile disturbances and paralysis.

Armadillos with leprosy

However, the ability to change host cells could be medically useful: Mycobacterium leprae in the liver apparently ensures that the organ grows while maintaining its healthy structure. A team led by Samuel Hess from the University of Edinburgh in Scotland has now demonstrated this in armadillos (Dasypus novemcinctus). Mammals native to the New World are the natural host of the leprosy bacteria.

Hess and his colleagues infected 32 adult leprosy-susceptible armadillos with the pathogen. Twelve uninfected individuals and 13 leprosy-resistant armadillos that were also infected but could not spread the bacteria served as controls. “Compared to uninfected and resistant animals, the livers of infected armadillos were significantly enlarged over ten to 30 months,” the researchers report. Infected individuals showed high numbers of bacteria in their livers.

growth without damage

The remarkable thing about it: “The enlarged infected liver had an intact architecture and vascular organization without damage, scarring or tumors,” the researchers said. Analysis of the cells showed that gene expression patterns similar to those observed in very young animals were activated in infected livers: genes related to metabolism, growth and cell proliferation were activated, and genes related to aging were reduced or suppressed.

The authors suspect that the bacteria reprogrammed the liver cells, returning them to an earlier stage of progenitor cells from which new liver cells can develop and new liver tissue can grow. This has the advantage for the bacteria that there is more tissue in which to spread. “If we can figure out how bacteria grow the liver as a functional organ without causing harmful effects in living animals, we might be able to use this knowledge to develop safer therapeutic measures to rejuvenate aging livers and regenerate damaged tissues,” says Hess’s colleague. Anura Rambukkana.

Help with liver disease?

Liver diseases currently lead to approximately two million deaths worldwide each year. In many cases, transplantation is the only option to save the patient. If what was left of a patient’s own liver could be regrown into a healthy organ, many liver-related deaths could likely be prevented. However, earlier studies that attempted to regenerate mouse livers using implanted stem cells were not very successful: in many cases, scarring and tumors formed.

Mycobacterium leprosy could open up promising new approaches: Although it is ruled out to intentionally infect patients with damaged livers with leprosy due to the severe symptoms of the disease in humans, the mechanisms used by the bacterium could be copied for therapies. . “The bacterial genome is a valuable resource for future studies,” say the researchers.

Quelle: Samuel Hess (University of Edinburgh, Scotland) et al., Cell Reports Medicine, doi: 10.1016/j.xcrm.2022.100820

Leave a Comment