Why do liver cells regenerate

Clearly the hepatocyte is not a terminally differentiated cell. Changes in gene expression associated with regeneration are observed within minutes of hepatic resection. An array of transcription factors are rapidly induced and probably participate in orchestrating expression of a group of hepatic mitogens. Proliferating hepatocytes appear to at least partially revert to a fetal phenotype and express markers such as alpha-fetoprotein. Despite what appears to be a massive commitment to proliferation, the regenerating hepatocytes continue to conduct their normal metabolic duties for the host such as support of glucose metabolism.

The processes and signals involved in shutting down the regenerative response are less well studied than those that stimulate it. TGF-beta1, which is known to inhibit proliferative responses in hepatocytes, is one cytokine involved in this process, but undoubtedly several others participate.

These devices support patients as their livers recover from disease or as they await liver transplants. Center for Regenerative Medicine researchers are refining their own version of a bioartificial liver, known as the Spheroid Reservoir Bioartificial Liver.

This device contains pig liver cell hepatocyte spheroids, which replace a patient's liver function. Research into using human hepatocytes in the device is underway.

Patient-specific liver cell transplantation. Existing liver cell transplantation procedures used to treat genetic liver diseases do not use patient-specific cells and require immunosuppression. Center for Regenerative Medicine researchers are developing an individualized approach to liver cell transplantation that uses the patient's own cells.

With this approach, cells would be collected from the patient and gene therapy would be used to correct the genetic defect responsible for the patient's disease. The corrected healthy cells would then be transplanted back into the patient's liver. As the corrected hepatocytes were originally derived from the patient's own cells, no immunosuppressive drugs would be needed. Proof-of-concept studies in the first genetically engineered large animal model of a metabolic liver disease have already been shown to be curative.

Mayo Clinic researchers are now planning to move this regenerative therapy to the clinical setting. Also, scientists are working to design devices to help patients with certain liver problems. These devices can temporarily help patients while they wait for a transplant, in a similar way to the dialysis machines that are used to help patients with kidney failure [ 5 ].

Tissue engineering is a branch of science that might also help patients who are waiting for a transplant. Tissue engineering uses special methods and materials to try to grow livers in the lab.

In the absence of donors, these lab-grown livers may be transplanted into the patients to improve or replace their damaged liver tissues. A huge part of the knowledge of the biological behavior of liver cells has been obtained studying the liver regeneration phenomenon.

This process is called decellularization , and it is done because the three dimensional structure or matrix that supports the cellular components of the liver is well-kept.

Observe in the picture the well-preserved blood vessels of the liver matrix. In this way, the clean liver can receive new hepatic cells from healthy people or animals and then be transplanted [ 6 ].

This process has been done successfully in several mammalian species, but it is difficult. Cleaning a rat liver can take 48 h, and cleaning a complete human liver can take up to 6 weeks! However, a problem to solve after the decellularization is getting enough healthy liver cells to refill the clean liver. Today, an alternative under study is the production of liver cells from stem cells located in or out of the liver.

But that is another story. The goal of writing this article was to inform young people about how the liver works in the body and to describe its amazing capacity to respond to different injuries.

Another goal was to provide knowledge about scientific research that is focused on improving the quality of life of people who have severe liver diseases. The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

The author would like to thank Dr. Patrick Weill, who assisted with English language editing. Gross and cellular anatomy of the liver. In Molecular Pathology of Liver Diseases. Experimental pathology of the liver. Restoration of the liver of the white rat following partial surgical removal. Liver regeneration versus direct hyperplasia. Department of Health and Human Services. Cell sources, liver support systems and liver tissue engineering: alternatives to liver transplantation.

Stem Cells — Organ reengineering through development of a transplantable recellularized liver graft using decellularized liver matrix. Share on Facebook. Core Concept Published: July 24,