One of the world’s oldest diseases may hold the secret to renewing aging livers

The bacterium that causes the infectious disease could potentially regrow liver cells.
Brittney Grimes
A medical doctor holding up an anatomical model of the human liver.
A medical doctor holding up an anatomical model of the human liver.


Researchers have discovered that leprosy bacteria can reprogram cells to increase the size of the liver in adult animals. This can be done without damaging or scarring the organ. It also did not create tumors when the liver grew in size.

Leprosy bacteria can renew aging livers

Leprosy, one of the oldest and most persistent infectious diseases, may have the ability to regenerate livers, according to a new study. The bacteria that causes the disease can also renew aging livers and allow humans to live disease-free for longer periods of time, also known as healthspan.

This discovery could also lead to regrowing damaged livers, which would reduce the need for liver transplants. Currently, a transplant is the only cure available for people with end-stage scarred livers. A prior study in 2013 was tested in the livers of mice, promoting the regrowth of their livers by creating stem cells and progenitor cells – the step following a stem cell that can form a cell for any type of organ. The regrowth required an invasive treatment that resulted in scarring and tumor growth, also called tumorigenesis.

In order to counteract the harmful side effects, researchers expanded on their previous breakthrough for liver regrowth by looking into their study involving Mycobacterium leprae (ML), the bacteria that causes leprosy.

One of the world’s oldest diseases may hold the secret to renewing aging livers
Mycobacterium leprae, the bacteria that causes leprosy.

The researchers studied the effects in armadillos, natural hosts to the bacteria

The research team, who worked with the U.S. Department of Health and Human Services in Baton Rouge, Louisiana, U.S., infected 57 nine-banded armadillos with the bacteria ML. The team chose the animals specifically because they are natural hosts of the leprosy bacteria.  Then, they compared the infected armadillos’ livers with those that were uninfected and others that were resistant to infection.

They noticed that the infected animals developed enlarged, healthy livers with the same vital components, such as blood vessels, bile ducts and functional units called lobules, as the uninfected and resistant animals. The team thinks the bacteria ‘hijacked’ the regenerative ability of the liver to increase the organ’s size, providing it with more cells to grow bigger, giving the organ the ability to increase and renew itself.

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Researchers also discovered several factors about the primary type of liver cells, called hepatocytes, suggesting the cells had reached a revived state in the infected armadillos.

One of the world’s oldest diseases may hold the secret to renewing aging livers
Hepatocyte cells.

In addition, the livers of the infected armadillos also contained gene expression patterns, which references the blueprint for building cells. The patterns were similar to those found in younger animals and human fetal livers. The genes linked to metabolism that are associated with growth, and cell production were activated, and the ones linked with aging were suppressed.

Reprogramming aging or damaged liver cells

The researchers believe this is because the leprosy bacteria reprogrammed the liver cells, returning them to an earlier stage the original, healthy cells. This allowed the cells to become new hepatocytes and grow new liver tissues. “If we can identify how bacteria grow the liver as a functional organ without causing adverse effects in living animals, we may be able to translate that knowledge to develop safer therapeutic interventions to rejuvenate aging livers and to regenerate damaged tissues,” said Anura Rambukkana, professor and lead author from University of Edinburgh’s Centre for Regenerative Medicine in Scotland.

The study was published today (Nov. 15) in the journal Cell Reports Medicine.

The research team wants the findings to eventually lead to the option of regrowing the cells of aging or damaged livers. This way, there can be alternatives to receiving liver transplants, by regenerating the liver itself.


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