Bone Marrow Stem Cell Slow Down Liver Damage

BBC News, September 26, 2007

Using stem cells taken from the bone marrow, scientists have developed a new way to treat liver failure by dampening the immune response.

The technique could help save human lives after it moves past animal testing.

Potentially, the liver would be given the maximum chance to repair itself as the patient could be kept alive longer until a donor organ is found. The journal PLOS One featured the work by The Massachusetts General Hospital.

With the ability to regenerate itself, the liver is one of the few major organs with this ability.

But diseases like chronic hepatitis, or excessive long-term alcohol consumption stress the organ to point that is too extensive to cope with.

Powerful drugs to suppress the immune response are required to avoid transplant rejection of donor organs -- this is necessary for the only current treatment for severe "end stage" damage. But still, donor organs themselves are limited.

External liver assist devices have successfully supported some patients, but such machines require a supply of (preferably) human liver cells, which have been difficult to acquire.

Tissues supporting blood cell development in the marrow cavity can be created using stem cells from bone marrow. The mesenchymal stem cells (MSCs) were used be the United States researchers.

By putting a brake on the movement of immune cells to areas of damage, previous research has shown that MSCs are able to inhibit several immune system activities.

MSC's can be expanded to levels that could be therapeutically useful after being extracted from a patient's own bone marrow.

To treat rats with liver failure, the researchers tested several ways of using the cells.

Simply transplanting MSCs into the animals' livers was not effective.

However, lessening inflammation and halting cell death were two methods of delivering molecules secreted by the cells.

Also, greatly reducing signs of liver failure in the animals, and boosted survival rates from 14% to 71%, was the result of cycling the blood of rats with liver failure through an external bioreactor containing MSCs.

To try to halt cell damage, and allow the organ to regenerate, a patient could be injected with a drug containing MSC-derived molecules in theory said researcher Biju Parekkadan.

A device similar to the bioreactor could be considered to buy extra time before a transplant if the initial efforts with the drug were not successful, or the damage was too extensive.

The research is still in an early stage warned the British Liver Trust.

But Professor Mark Thursz, of St Mary's Hospital, London and spokesperson for the trust, said: "A long standing goal in hepatology is the suppression of liver cell death until regeneration could occur."

"This development could potentially reduce the number of donor organs used in urgent transplant procedures thereby increasing the number available for the growing number of patients on routine waiting lists."