And the lymph nodes near the liver are close enough to receive chemical distress signals sent by dying tissue from a diseased liver, Lagasse says. These signals are intended to stimulate the regeneration of any remaining healthy liver tissue, but this does not work in cases of severe disease. However, the signals appear to aid the growth of liver tissue in neighboring lymph nodes.
“It’s amazing,” says Gouon-Evans. “Having this little incubator in the body [that can grow organs] it’s just amazing.”
About five years ago, Lagasse, along with businessman and drug developer Michael Hufford and transplant surgeon Paulo Fontes, founded LyGenesis to take the technology further. The team is exploring the use of lymph nodes to grow new thymus glands, kidneys and pancreas.
But the company’s priority is the livers. Over the past 10 years, team members have collected promising evidence suggesting they can use their approach to grow new mini-livers in mice, pigs and dogs. Mini-livers don’t grow indefinitely: the body has an internal regulator that stops liver growth at a certain point, which is why healthy livers don’t overdo it when they regenerate.
The teams mouse research with a genetic liver disorder has shown that most cells injected into a lymph node will stay there, but some will migrate to the liver, provided there is enough healthy liver tissue left. These migratory cells can help the remaining liver tissue to regenerate and heal. When this happens, the new mini-liver in the lymph node will shrink, keeping the total amount of liver tissue in balance, says Lagasse.
Other studies have focused on pigs and dogs that have diverted the blood supply to the liver, causing the organ to die. Injecting liver cells into the animals’ lymph nodes will ultimately rescue their liver function.
In the pig studyFor example, the team first surgically diverted the blood supply from the liver in six animals. Once the pigs had recovered from surgery, the team injected healthy liver cells into their lymph nodes. Doses ranged from 360 million cells injected in three lymph nodes to 1.8 billion cells in 18 lymph nodes.
Within a couple of months, all the animals seemed to recover from liver damage. Tests suggested that his liver function had improved. And when the team later autopsied the animals, the new organs in the lymph nodes closely resembled healthy miniature livers, each up to about 2% the size of a typical adult liver. Other studies suggest that it takes about three months for the treatment to have significant benefits.