The extraordinary regenerating liver

The liver is an incredible example of an organ that can regenerate when it’s injured; in fact, it’s so good that live liver donations are possible where a person gives away up to 80% of their liver to a new recipient and then regrows themselves a new one! Martin Boughen has personally experienced how well the liver can regenerate.

Martin - My adult son suffered from a complex and rare immune condition that progressed to end stage liver failure just four years after diagnosis. The transplant was only chance for life. Despite being on the active transplant list, my son's condition was approaching critical and he may not have lived long enough given a shortage of suitable organs and patient priorities. I was carefully assessed both physically and psychologically before the transplant unit was given permission to transplant some of my liver into my son. I donated 61 percent of my liver. It was the most I could safely offer and the effect to my body and potential to save my son's life was measured. I was in surgery for six hours followed by 24 hours in ICU and released from hospital after just 10 days. My liver regenerated to its near original mass and function within twelve weeks. My liver is a strange shape now and uncomfortable at times but works. The living donor transplant worked long enough to save my son's life. Sadly he needed a full transplant just three months later due to serious complications with the original disease. Six years later is living the life he so richly deserves. For me live liver donation is a very important issue. Advancements in medical and surgical procedures make a living donation a very viable option in the right circumstances and in my opinion this option could be offered earlier rather than waiting for the patient to be so ill that it may be the only option left open to try.

But why does the liver have this extraordinary regenerative capacity in the first place?  Eva Higginbotham heard from Meritxell Huch, who's trying to find out at Cambridge University’s Gurdon Institute...

Meritxell - Because the liver has this property of detoxification every day it gets injured. The liver has evolved to have a very huge capacity to restore these cells back and restore their normal state of the liver.

Eva - How does it do that? How does it grow back?

Meritxell - That's very interesting and is actually very important question to address. We know that it does it and it does it very well. The molecular mechanism how the cells know they have to regrow how the cells know they have to stop growing because the liver is regenerated, we know which factors are important, but we don’t know all of them and we don't know how they do it. There is a lot of investigation on that area. Obviously we think that if we understand how the liver regenerates well we might be able to apply it to other organs and understand why the other organs cannot do it.

Eva - What about when things go wrong in the liver?  You hear about people damaging their liver with alcohol for example, what happens there?

Meritxell - Yeah. We get many patients that have what we call alcoholic liver disease. Their livers have been damaged because of drinking alcohol and liver disease is actually one of the diseases that is increasing because despite you can injure the liver in a daily basis and it can to grow, is not an infinite capacity.

That means that at some point for reasons that we still don't understand, it will stop regenerating. And when the tissues stop regenerating it has only two options. Either it undergoes a scar, the function is lost and is replaced by cells that do not have this detoxifying function of the liver. Or the other option is that actually it grows cancer because in regeneration the mechanism is that the cells have to sense the damage and respond to the damage by proliferating in order to make a new pool of cells. If you have a lot of proliferating shells on the liver you are susceptible to that mutations and therefore you're susceptible to cancer and alcohol has a huge influence on liver disease because it's a constant damage to the tissue.