An article published in Current Gerontology and Geriatrics Research discussed that many organ systems exhibit significant age-related deficits, but based on studies in old rodents and elderly humans, the liver appears to be relatively protected from such changes. A remarkable feature of the liver is its capacity to regenerate its mass following partial hepatectomy.

Evidence suggests that aging compromises the livers regenerative capacity, both in the rate and to the extent the organs original volume is restored. However, there has been modest definitive information as to which cellular and molecular mechanisms regulating hepatic regeneration are affected by aging.

Changes in hepatic sensitivity to growth factors—for example, epidermal growth factor (EGF)—appear to influence regeneration in old animals. On the other hand, recent studies suggest that reduced phosphorylation and dimerization of the EGF receptor—critical steps in the activation of the extracellular signal-regulated kinase pathway—and subsequent cell proliferation are responsible. While other studies have demonstrated that aging affects the upregulation of a Forkhead Box transcription factor (FoxM1B) – essential for growth hormone-stimulated liver regeneration.

Hence, aging appears to compromise liver regeneration by influencing several pathways, the result of which is a reduction in the rate of regeneration, but not in the capacity to restore the organ to its original volume.

Furthermore, the relative efficacies of normal, cell-cycle-induced hepatocyte proliferation versus an independent pathway involving hepatocyte hypertrophy in maintaining liver functions requires additional study; the roles of VEGF, serotonin and liver sinusoidal pseudocapillarization require further investigation.

Most evidence supports the concept that the age of the liver donor or recipient exerts only a modest impact on post-transplantation patient’s survival. The findings suggest that a pre-transplantation regimen of growth factors in potential elderly liver recipients merits further consideration.

Source: Current Gerontology and Geriatrics Research. Volume 2011. Article ID 526379. https://doi.org/10.1155/2011/526379