Liver Regeneration Coming?

Liver damage due to the infiltration of plasma cells in Multiple Myeloma victims is one of the collateral effects of the cancer. The liver is the body’s filter, removing toxins from the bloodstream. The only solution to liver failure is transplant, but with only 6,000 organs becoming available for the 100,000 potential recipients each year, it could be a very long wait. When it’s necessary to give those organs to those who might reap the greatest potential, cancer sufferers aren’t likely to make the waiting list with any reasonable expectation.

However, researchers at University of Pittsburgh’s McGowan Institute for Regenerative Medicine have found a way to turn any of the approximately 500 lymph nodes in the human body into incubators to grow an entirely new liver, and one for which rejection isn’t an issue. The lymph nodes are small, oval shaped organs where immune cells collect to fight pathogens that have invaded the body. Pitt’s researcher Eric Lagasse came up with the idea in 2007 as he was studying ways to overcome obstacles to liver regeneration. When liver damage occurs, scar tissues are formed which effectively block access to areas of the liver, rendering them useless. He notd that transplanted liver cells could survive in unusual areas of the body, like beneath the renal capsule –a fibrous layer that protects the kidney.

Lagasse thought that if he could transplant liver cells away from the diseased and damaged organ, instead of dying, the cells just might multiply and do well. He used mice with end stage liver disease as a test bed by implanting hepatocytes (liver cells) from healthy mice into the kidney capsules as well as subcutaneously and in their spleens.  Most of the mice died within the eight weeks usual for mice with end stage liver disease. But when he injected the cells into the bellies of the mice, they regained weight and inside a few weeks showed to be energetic and healthy. He observed those mice for a few months, and then performed the same experiment, this time using flourescent dyes to trace the pathways of the liver cells. He found that they had migrated to the lymph nodes where they grew into nodules. Combined, these nodules created enough liver function to keep the mice healthy.

It made sense to Lagasse, lymph nodes can be excellent bioreactors because of their unusual ability to expand, good access to the bloodstream, and access to hormones and other compounds required to induce cell growth. With an abundance of lymph nodes in the body, it doesn’t sacrifice much to have them trade their original function for new ones like those of the liver. Continuing his experiments, Lagasse discovered that if he injected the liver cells directly into the lymph nodes, they got the signal to grow from proteins released into the body by the dying liver.  Lagasse says there is some mysterious connection or communication between the failing liver and the new ones grown in the lymph glands. He then says that the metod of that communications isn’t important, the important part is that it happens and the process works.

His methodology employed in mice gives up to 70 percent of the original mass of the normal liver. No adverse reactions have appeared. Rejection isn’t a problem because the mice were genetically engineered to have the same DNA. This eliminates the possibility that the body’s immune system would attack the hepatocytes as invaders. Legasse says that in humans, immunosupression drugs would have to be relied on to prevent rejection.

The concept is still relatively young, with a ways to go to reach maturity. But it does offer a tantalizing image of a possible future. It’s a long way from mice to human trials, but the basic concept has been proven sound