The bacteria that causes leprosy can rejuvenate and regrow liver tissue without harmful side effects. Patients with impaired liver function may benefit from this finding in the future.
Biologist Samuel Hess, at the University of Edinburgh in Scotland, found that in armadillos infected with the leprosy bacteria, liver cells reverse their aging and start dividing again. This is how the body forms new, healthy liver tissue. In addition, even the blood supply to the brand new tissue is fully functional.
In the experiment, Hess and his team used nearly 60 armadillos, which they infected with the leprosy bacteria Mycobacterium leprae. They then monitored the animals for more than three years. The team made ultrasounds of the animals to record the development of new liver tissue.
READ ALSO
Obesity medication is not a quick fix
Rats, mice or primates usually play the role of laboratory animals. Therefore, the choice of armadillos in this study is at least striking. Nevertheless, according to gastrointestinal and liver scientist Roel Bennink, affiliated with Amsterdam UMC, this preference is not illogical. ‘Over the years, armadillos and the leprosy bacteria have entered into a kind of collaboration,’ he says. ‘In this way, the armadillo has become a natural host for the bacteria. The bacteria can survive in the liver without harming the animal. That balance makes the armadillo ideal for this research.’
Most organs in the human body cannot form new, healthy tissue once damaged or aged. The liver can do that to a certain extent. The findings of Hess and his colleagues are therefore promising for people with impaired liver function.
tumors
‘There are various causes of liver damage,’ says Bennink. ‘Think of an inflammation of the liver, excessive scarring or fattening of the tissue due to obesity. A tumor that has to be surgically removed is also a regular occurrence.’
According to Bennink, the latter group in particular can benefit from Hess’s discovery. ‘If you remove liver tissue with a tumor in it, a piece of the liver is often too small to recover and live a healthy life. To ensure that a surgeon can safely remove the tumor, sufficient healthy tissue must be present in the patient before he enters the operating room. You can achieve this by stimulating the liver to grow. The problem is that we can only do that at the moment by doing some damage to the liver first.’ Hess shows that an infection with the leprosy bacteria in armadillos has the same effect.
‘The bacteria knows a trick that ensures that liver cells rejuvenate and divide,’ says Bennink. ‘The question now is which mechanisms play a role in this, and whether we can imitate them.’
Nevertheless, according to him, it is impossible that the leprosy bacteria can be used as a medicine in the short term because of the major health risks associated with it. After all, patients should not run the risk of actually developing the disease leprosy. ‘Mycobacteria are dangerous. Consider, for example, the bacterium that causes TB: it belongs to the same group.’
Trick
Moreover, stimulating tissue growth is a thorny issue in biology. The dividing line between controlled growth and unrestrained tumor formation is thin, says Bennink. The fact that the armadillos’ grafted liver tissue showed no signs of tumor growth is no guarantee that the method is safe in humans.
‘The concept is very interesting and can certainly contribute to better techniques for performing operations safely,’ says Bennink. ‘But a great deal of research is still needed. Before we can improve our current methods, we first need to discover how the leprosy bacteria work in the armadillos. Only then can we start pushing all kinds of buttons ourselves.’