Liver Failure After Extended Hepatectomy in Mice Is Mediated by a p21-Dependent Barrier to Liver Regeneration

doi:10.1053/j.gastro.2012.08.043

Gastroenterology

Volume 143, Issue 6, December 2012, Pages 1609-1619.e4

https://doi.org/10.1053/j.gastro.2012.08.043 Get rights and content

Background & Aims

Extended liver resection leads to hepatic failure because of a small remnant liver volume. Excessive parenchymal damage has been proposed as the principal cause of this failure, but little is known about the contribution of a primary deficiency in liver regeneration. We developed a mouse model to assess the regenerative capacity of a critically small liver remnant.

Methods

Extended (86%) hepatectomy (eHx) was modified to minimize collateral damage; effects were compared with those of standard (68%) partial hepatectomy (pHx) in mice. Markers of liver integrity and survival were evaluated after resection. Liver regeneration was assessed by weight gain, proliferative activity (analyses of Ki67, proliferating cell nuclear antigen, phosphorylated histone 3, mitosis, and ploidy), and regeneration-associated molecules. Knockout mice were used to study the role of p21.

Results

Compared with pHx, survival of mice was reduced after eHx, and associated with cholestasis and impaired liver function. However, no significant differences in hepatocyte death, sinusoidal injury, oxidative stress, or energy depletion were observed between mice after eHx or pHx. No defect in the initiation of hepatocyte proliferation was apparent. However, restoration of liver mass was delayed after eHx and associated with inadequate induction of Foxm1b and a p21-dependent delay in cell-cycle progression. In p21^-/- mice, the cell cycle was restored, the gain in liver weight was accelerated, and survival improved after eHx.

Conclusions

Significant parenchymal injury is not required for liver failure to develop after extended hepatectomy. Rather, liver dysfunction after eHx results from a transient, p21-dependent block before hepatocyte division. Therefore, a deficiency in cell-cycle progression causes liver failure after extended hepatectomy and can be overcome by inhibition of p21.

Section snippets

Animals

All animal experiments were performed in accordance with Swiss Federal Animal Regulations and approved by the Veterinary Office of Zurich. Animals aged 10–12 weeks were kept on a 12-hour day/night cycle with free access to food and water. C57Bl/6 mice were obtained from Harlan (Horst, The Netherlands); p21 knockout animals and corresponding wild types (B6129SF2/J) were obtained from Jackson Laboratories (Bar Harbor, ME).

Animal Surgery

Anesthesia was induced by isoflurane inhalation (2%–4%), and preoperative

Extended Hepatectomy Induces Liver Failure in Mice

To provoke a murine entity reminiscent of human SFSS, extended 86% hepatectomy (eHx) was performed on C57Bl/6 mice with ligature of the vascular pedicle before resection (Figure 1A and B). This modification was performed to protect critical structures from close mass ligatures and to reduce blood loss. The outcome was compared with the standard model of pHx, which induces active liver regeneration. In contrast to pHx after which no increase in cholestatic parameters was observed,

Discussion

Under physiologic conditions, the liver has an unmatched potential to regenerate after major tissue loss. In mice, restoration of the initial liver mass usually is completed within a few days.¹⁷ If tissue loss is too extensive, resection can lead to acute liver failure in mice, akin to human SFSS.4, 5, 6, 7 Whether a diminished regenerative capacity of small liver remnants contributes to liver failure is unclear. Blunted regeneration leading to hepatic dysfunction has been observed in different

Acknowledgments

The authors would like to thank Udo Ungethuem, Heidi Seiler, Martha Bain, and Pia Fuchs for their excellent technical assistance, and Carol de Simio for her help with drawing Figure 1.

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: Conflicts of interest The authors disclose no conflicts.

: Funding Supported by a grant from the Liver and Gastrointestinal Disease Foundation (LGID) (P.A.C.), and the Olga Mayenfisch Foundation (K.L.), the Center for Clinical Research, University and University Hospital Zurich (K.L.), the Amelie Waring Foundation (K.L. and O.T.), as well as from the Swiss National Foundation (32003B-109906 to P.A.C.).

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Original ResearchBasic and Translational—LiverLiver Failure After Extended Hepatectomy in Mice Is Mediated by a p21-Dependent Barrier to Liver Regeneration

Background & Aims

Methods

Results

Conclusions

Section snippets

Animals

Animal Surgery

Extended Hepatectomy Induces Liver Failure in Mice

Discussion

Acknowledgments

Am J Pathol

Curr Opin Cell Biol

Am J Surg

Cancer Cell

Am J Transplant

What is critical for liver surgery and partial liver transplantation: size or quality?

Hepatology

Strategies for safer liver surgery and partial liver transplantation

N Engl J Med

RAGE limits regeneration after massive liver injury by coordinated suppression of TNF-alpha and NF-kappaB

J Exp Med

A complement-dependent balance between hepatic ischemia/reperfusion injury and liver regeneration in mice

J Clin Invest

Interleukin-6 inhibits oxidative injury and necrosis after extreme liver resection