Does a liver regenerate after partial hepatectomy (surgical removal of part of the liver)?

From the Guidelines

Yes, the liver does grow back after partial donation, with the remaining liver tissue regaining about 90% of its original volume within 2-3 months after surgery, as supported by recent studies such as 1. The liver is a remarkable organ with the unique ability to regenerate itself. When a portion of the liver is surgically removed for donation, the remaining liver tissue in both the donor and recipient will grow to compensate for the lost volume. This regenerative capacity is possible because liver cells (hepatocytes) can rapidly divide to restore liver mass when needed, as seen in the rapid hypertrophy of the future liver remnant (FLR) after resection, with restoration of liver mass and function within a few weeks 1. During recovery, donors should follow their medical team's guidance regarding activity restrictions, typically avoiding heavy lifting for 6-8 weeks and strenuous exercise for 3 months. They should also avoid alcohol for at least 3 months and take prescribed pain medications as directed. Some key points to consider in liver regeneration include:

• The mechanism of liver regeneration after partial donation is complex and involves the combination of peri-portal inflammation and the diversion of portal venous blood to the FLR, as described in 1.
• The increase in FLR volume after partial donation is due to both clonal expansion and cellular hypertrophy, with the extent of post-donation liver growth being proportional to the degree of portal flow diversion 1.
• Rapid FLR growth can be expected within the first 3–4 weeks after partial donation and continues up to 8 weeks, as reported in 1. This remarkable regenerative ability is what makes living liver donation possible and successful for both donors and recipients, with complete functional recovery usually occurring within 6-12 months, as supported by the current guidelines and narrative review in 1.

From the Research

Liver Regeneration After Partial Donation

• The liver has a unique ability to regenerate itself after partial donation, with studies showing that the liver can grow back to its original size or even exceed it 2, 3.
• A study published in 2004 found that living donors who donated their right lobe had attained 78.6% of their ideal liver volume at 3 months postoperatively, with a 1.85-fold increase in liver size compared to immediately postoperatively 2.
• Another study published in 2008 found that the remnant liver volume in right lobe donors increased rapidly to 68.9% at 1 month and 89.8% at 6 months, with the regeneration ratios being almost the same in all donor groups at 6 months 3.
• The recipient liver also regenerates rapidly, with one study finding that the liver volume increased rapidly until 2 months, exceeding the standard liver volume, and then gradually decreased to 90% of the standard liver volume 3.

Factors Affecting Liver Regeneration

• The use of certain immunosuppressive medications, such as sirolimus, may affect liver regeneration, with one study finding that sirolimus was associated with lower levels of hepatocyte proliferation compared to sirolimus-free patients 4.
• Another study found that the use of sirolimus with reduced-dose tacrolimus was associated with higher rates of graft loss, death, and sepsis compared to the use of conventional-dose tacrolimus alone 5.
• However, sirolimus may be effective in treating certain immune-mediated disorders in pediatric liver transplant recipients, with one study finding that conversion from tacrolimus to sirolimus resulted in complete resolution of symptoms in 50% of patients 6.

Overall Regeneration Patterns

• The liver regeneration pattern can vary depending on the type of donation and the individual patient, with some studies finding that the right lobe donor group regenerated fastest in the donor groups, and the recipient liver regenerated faster than the donor liver 2, 3.
• Overall, the liver has a remarkable ability to regenerate itself after partial donation, and further research is needed to fully understand the factors that affect liver regeneration and to optimize immunosuppressive regimens for liver transplant recipients 2, 4, 5, 3, 6.