Understanding transplants


I'm new to all this so please forgive my lack of understanding. I'm trying to figure out how a transplant could potentially cure PSC. PSC is a disease of the bile ducts and after transplant the patient still has the same ducts. I know you all already figured this one out, could anyone explain how it works?



Structurally, most of the ductwork is inside of the liver and gets replaced with the new organ. If the common hepatic duct outside the liver is damaged by PSC, it is removed and the new liver is typically attached to the small intestine further downstream.

As far as why PSC usually doesn't come back in the new liver, I don't think anyone knows that answer yet largely because nobody knows what causes PSC in the first place. Research is suggesting there is a genetic component to what triggers PSC and if the new organ is dissimilar enough the disease is unable to recur. Rates of PSC recurrence are much higher if the living donor organ is sourced from a child or a parent when compared to an organ sourced from a spouse or a friend.

Thanks again JTB. So for live donors, one will keep his own intrahepatic plumbing. I knew the stats about family members. If we get to the transplant point it will have to be from someone outside the family.

Yes and no about the plumbing. The live donor will regain full liver size and function when the liver regrows but will lose some of the redundant structure built into the liver after the operation because the surgeons can only sew together the bits outside the liver (extrahepatic). A normal liver has two major bile ducts, one going to each lobe. A normal liver also has 2-3 portal veins and portal arteries, one each to the left and right lobes (and another sometimes in the center). Think of each of these ducts/veins/arteries as a tree with a single trunk outside the liver but with lots of branches inside the liver. During the procedure one of these major bile ducts and 1-2 of the portal veins and arteries each are cut outside the liver along with one of the lobes. These extrahepatic ducts, veins, and arteries are then sewn into the matching extrahepatic structure in the recipient. The remaining duct, veins, and arteries for both the donor and recipient are blocked off because there is nothing for them to plug into (there is no second lobe). Eventually the liver regrows, but it is structurally closer to one giant lobe. Both the donor and recipient are much more susceptible to future bile duct issues because the entire liver drains through a single duct rather than two. This loss of structure also means that the decision to donate part of a liver is a one time deal.

Thank you so much for your explanation. I finally get it, and I understand why one can give only once. Thanks for taking the time to write this. I hope that this exchange helped others on this list too.

Good night,