Extended 78% Hepatectomy in a Mouse Surgical Model

The scope of our research is to evaluate therapeutic strategies to enhance liver regeneration and repair that could aid in improving patients'outcomes in the setting of liver transplantation using marginal liver grafts as well as extended liver resection for cancer that are at higher risk for primary non-function and acute hepatic failure. Our team utilizes genomic, proteomic, and metabolomic platforms to study liver regeneration and identify novel therapeutic targets to improve outcomes. The focus of our laboratories is to develop state-of-the-art gene therapy platforms to deliver the hepatoprotective and liver regenerative gene A20.

We uncovered a potent hepatoprotective function for A20, also called TNFAIP3, through its combined anti-inflammatory, anti-apoptotic, and proproliferative functions in hepatocytes. Liver-targeted A20 gene therapies protected from lethality in mouse models of toxic hepatitis, extended 78%and lethal radical hepatectomies 90%and also prolonged liver ischemia. Recent promising pretranslational studies in large animal prelude clinical translation of this therapy.

This protocol offers a unique surgical model designed for investigating small-for-size syndrome as well as assessing therapeutic strategies to improve outcomes of extensive hepatectomies for cancer and increased successful rates of marginal and extended criteria liver grafts. When the 78%hepatectomy is performed correctly, this procedure results in approximately 50%postoperative survival as opposed to nearly 100%survival associated with the classical two-thirds partial hepatectomy in healthy mice. To begin, place the anesthetized mouse in the supine position.

After making a vertical midline laparotomy incision, enter the peritoneal cavity by incising through the linea alba with sharp scissors up to the length of the skin incision. Then, clamp the xiphoid process with a hemostat, retract the sternum superiorly, and, using appropriate retractors, open the abdominal wall laterally. Gently pull the exposed liver down and transect the falciform ligament along the length of the liver using sharp scissors.

After retracting the liver superiorly towards the thorax, transect the hepatogastric ligament and intrahepatic lobe ligaments using sharp micro scissors. Next, retract the median lobe superiorly, keeping the left lobe in its original anatomic position. Wrap a 5-0 silk suture around the superior medial part of the left lobe.

Subsequently, reflect the left lobe superiorly towards the thorax to expose the undersurface and tie the suture at the base to secure the ends. Using sharp scissors, resect the left lobe distally to the suture knot, maintaining a two-millimeter tissue cuff between the suture and the resected lobe edge. After lifting the median lobe towards the chest, wrap a 5-0 silk suture around its base and position the lobe back in place.

Secure and tie the suture ends over the lobe's base, then resect the ligated median lobe, leaving a small cuff of tissue around the suture tie. After confirming hemostasis, mobilize the liver from right to left and carefully retract the exposed right upper and lower lobes medially and inferiorly. Using a 5-0 suture, encircle the superior medial aspect of the right upper lobe and then reflect the lobe towards the thorax.

Then wrap and tie the suture underneath the right upper lobe and resect it, leaving a small cuff of remnant tissue. Reposition the remaining liver to its natural anatomic location. To maintain hemostasis, apply pressure with gauze to bleeding areas at resected liver margins.

Finally, close the midline abdominal wall using a 5-0 polyglactin suture, followed by the skin incision with a 5-0 monofilament suture. Typically, mice death occurs within two to three days, but a 50%postoperative survival rate was observed in healthy mice within one week following an extended 78%hepatectomy.