A bioartificial liver device (BAL) is an artificial extracorporeal supportive device for an individual who is suffering from acute liver failure. An extracorporeal medical procedure is any medical procedure which is carried outside the body. ... Acute liver failure is the appearance of severe complications rapidly after the first signs of liver disease (such as jaundice), and indicates that the liver has sustained severe damage (loss of function of 80-90% of liver cells). ...

Use

The purpose of BAL-type devices, currently, is not to permanently replace liver functions, but to serve as a supportive device,^[1] either allowing the liver to regenerate properly upon acute liver failure, or to bridge the individual's liver functions until a transplant is possible. Liver function tests (LFTs or LFs), which include liver enzymes, are groups of clinical biochemistry laboratory blood assays designed to give information about the state of a patients liver. ... Acute liver failure is the appearance of severe complications rapidly after the first signs of liver disease (such as jaundice), and indicates that the liver has sustained severe damage (loss of function of 80-90% of liver cells). ... Liver transplantation is the replacement of a diseased liver with a healthy liver allograft. ...

Function

BALs are essentially bioreactors, with embedded hepatocytes (liver cells) that perform the functions of a normal liver. They process oxygenated blood plasma, which is separated from the other blood constituents.^[2] Several types of BALs are being developed, including hollow fiber systems and flat membrane sheet systems.^[3] A bioreactor may refer to any device or system that supports a biologically active environment. ... Hepatocytes make up 60-80% of the cytoplasmic mass of the liver. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... For the bird, see Liver bird. ... Blood plasma is the liquid component of blood, in which the blood cells are suspended. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ...

Hollow fiber system

One type of BAL is similar to kidney dialysis systems that employ a hollow fiber cartridge. Hepatocytes are suspended in a gel solution, such as collagen, which is injected into a series of hollow fibers. In the case of collagen, the suspension is then gelled within the fibers, usually by a temperature change. The hepatocytes then contract the gel by their attachment to the collagen matrix, reducing the volume of the suspension and creating a flow space within the fibers. Nutrient media is circulated through the fibers to sustain the cells. During use, a patient's blood is fed into the space surrounding the fibers. The fibers, which are composed of a semi-permeable membrane, facilitate transfer of toxins, nutrients and other chemicals between the blood and the suspended cells. The membrane also keeps immune bodies, such as immunoglobulins, from passing to the cells to prevent an immune system rejection. ^[4] This article is about clinical dialysis; for the laboratory technique, see Dialysis (biochemistry) In medicine, dialysis is a method for removing waste such as urea from the blood when the kidneys are incapable of this, i. ... Tropocollagen triple helix. ... Schematic of antibody binding to an antigen An antibody is a protein complex used by the immune system to identify and neutralize foreign objects like bacteria and viruses. ...

Comparison to liver dialysis

The advantages of using a BAL, over other dialysis-type devices (e.g. liver dialysis), is that metabolic functions (such as lipid and plasma lipoprotein synthesis, regulation of carbohydrate homeostasis, production of serum albumin and clotting factors, etc.), in addition to detoxification, can be replicated without the use of multiple devices. There are currently several BAL devices currently in clinical trials. Liver dialysis or artificial extracorporeal liver support is a detoxification treatment for liver failure and has shown promise for patients with hepatorenal syndrome. ... Some common lipids. ... A lipoprotein is a biochemical assembly that contains both proteins and lipids. ... Lactose is a disaccharide found in milk. ... Homeostasis is the property of either an open system or a closed system,[1] especially a living organism, to regulate its internal environment to maintain a stable, constant condition. ... It has been suggested that this article or section be merged into serum albumin. ... Coagulation is the thickening or congealing of any liquid into solid clots. ... Detox, short for detoxification, in general is the removal of toxic substances from the body. ...

A series of studies in 2004 showed that a BAL device reduced mortality by about half in acute liver failure cases ^[5]. The studies, which covered 171 patients in the U.S. and Europe, compared standard supportive care to the use of a bioreactor device using pig liver cells.

See also

• Artificial extracorporeal liver support
• Liver dialysis
• Tissue engineering

Artificial extracorporeal liver support is term that is used to describe measures that are used to carry-out liver function and are outside of the body. ... Liver dialysis or artificial extracorporeal liver support is a detoxification treatment for liver failure and has shown promise for patients with hepatorenal syndrome. ... Tissue engineering is the use of a combination of cells, engineering and materials methods, and suitable biochemical and physio-chemical factors to improve or replace biological functions. ...

References

1. ^ Allen J, Hassanein T, Bhatia S (2001). "Advances in bioartificial liver devices". Hepatology 34 (3): 447-55. PMID 11526528.  Free Full Text.
2. ^ Strain A, Neuberger J (2002). "A bioartificial liver--state of the art". Science 295 (5557): 1005-9. PMID 11834813. 
3. ^ Current Work on the Bioartificial Liver
4. ^ University of Minnesota Bioartificial Liver: How it Works
5. ^ Major study: Bioartificial liver reduces mortality by 44 percent in acute liver-failure patients