Liver Progenitor Cells in Massive Hepatic Necrosis-How Can a Patient Survive Acute Liver Failure?

Liver Regeneration in Acute on Chronic Liver Failure

Liver regeneration is a multifaceted process by which the organ regains its original size and histologic organization. In recent decades, substantial advances have been made in our understanding of the mechanisms underlying regeneration following loss of hepatic mass. Liver regeneration in acute liver failure possesses several classic pathways, while also exhibiting unique differences in key processes such as the roles of differentiated cells and stem cell analogs. Here we summarize these unique differences and new molecular mechanisms involving the gut-liver axis, immunomodulation, and microRNAs with an emphasis on applications to the patient population through stem cell therapies and prognostication.

Loss of liver function in chronic liver disease: An identity crisis

Adult hepatocyte identity is constructed throughout embryonic development and fine-tuned after birth. A multinodular network of transcription factors, along with pre-mRNA splicing regulators, define the transcriptome, which encodes the proteins needed to perform the complex metabolic and secretory functions of the mature liver. Transient hepatocellular dedifferentiation can occur as part of the regenerative mechanisms triggered in response to acute liver injury. However, persistent downregulation of key identity genes is now accepted as a strong determinant of organ dysfunction in chronic liver disease, a major global health burden. Therefore, the identification of core transcription factors and splicing regulators that preserve hepatocellular phenotype, and a thorough understanding of how these networks become disrupted in diseased hepatocytes, is of high clinical relevance. In this context, we review the key players in liver differentiation and discuss in detail critical factors, such as HNF4α, whose impairment mediates the breakdown of liver function. Moreover, we present compelling experimental evidence demonstrating that restoration of core transcription factor expression in a chronically injured liver can reset hepatocellular identity, improve function and ameliorate structural abnormalities. The possibility of correcting the phenotype of severely damaged and malfunctional livers may reveal new therapeutic opportunities for individuals with cirrhosis and advanced liver disease.