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FDA Testing Artificial Liver
NIckGorton writes "Research is now underway in the US to seek FDA approval for an artificial liver. The Extracorporeal Liver Assist Device (ELAD) filters blood through a cartridge containing immortalized human liver cells with fiber tubes running through that allow the patients blood to interact with them. This allows the matrix of liver cells to perform both the metabolic (cleansing the blood of toxins/waste) and synthetic (producing albumin, clotting factors, etc) functions of the patient's failing liver. A small trial in China showed a statistically and clinically significant difference in 30 day survival with ELAD."
I for one, and this might just be my superstitious self, would be concerned about the prospect of my bodily fluids interacting with biological material that has been, so to speak, "immortalized."
Don't blame me, I voted for Baltar.
Hm, immortal. How is that different from cancerous? And all of the immune cells are really carefully filtered out so there's no potential for graft-vs-host disease if one gets loose in the patient, right?
Bruce Perens.
As a two time kidney transplant recipient myself, I know how hard it is to live with organ failure. I met a guy who had gone through 3 liver transplants, and hepatitis had killed all of them. He is all right now,on his fourth transplant, but something like this can make all the difference in the world to people waiting for a liver. Especially since he had two small daughters.
Ultimately, as we understand more, i believe the mechanisms of cancer will be more harnessed than eliminated.
That which does not kill us makes us... st
There's no information about the interface of this device to the patient. Blood flow to the liver is rather unique (http://biology.about.com/library/organs/bldigestliver.htm), with 3/4 of its bloodflow coming from the portal vein and 1/4 from the hepatic artery. The blood mixes before being processed by the liver.
Is the device similarly fed by both arterial and venous sources? How is the pressure compensated? Where is the output reintroduced? Does the device run in parallel to the natural liver or in series? If the latter, which receives the blood first? Does it attempt to handle any of the other numerous functions of the liver such as the creation of bile or lymph?
Some background on why an artificial liver is a really big deal, and why it has been really hard until now to produce one:
(Any doctors or biologists more knowledgeable can fill in the gaps and correct me)
The liver breaks down toxins in the blood by metabolizing them. That is, they get broken down into simpler compounds by chemical reactions that take place in and around living cells. Contrast this with dialysis - an artificial kidney - which is able to work by filtering out chemicals based on molecular weight. Dialysis uses bundles of membranes that allow relatively light molecules (such as water) to pass through, but block heavier ones. The stuff the liver breaks down are too unwieldy or complex to be filtered out based just on weight - there are lots of other, good things in the blood that are of similar weight or complexity. A simple filter can't distinguish them; hepatocytes (liver cell clusters) can.
The task of creating the filtering membrane of a dialysis machine is a relatively well understood materials and processing problem. An artificial liver, which usually has a mini dialysis unit on the front or back end, also requires you to have living clusters of cells, and keep them alive, nourished, and healthy long enough for them to do some effective and therapeutic blood filtering. That's a much trickier biological problem, and we are only now getting decent at it.
The uses for a bio-artificial liver is huge. It can help people with chronic liver failure live longer and healthier lives, true, but it has more uses than that. The liver, as it turns out, is one of the few organs that can regenerate itself. If it is damaged by disease or some toxic insult, it is possible for it to repair itself if given the chance (in normally healthy people - the liver can also be damaged beyond repair). The problem is that in lots of cases the patient will die before the liver gets a chance to heal, leaving two options: hope for a liver transplant on really short notice, or die. A device like this can be a bridge to transplant or, in some cases, take the burden off the liver long enough for it to heal itself.
"we didn't want to worry about medical ethics"
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