"Off-The-Shelf" Bioartificial Liver Support System Using Cryopreserved Immobilized Hepatocyte Spheroids in a Porcine Acute Liver Failure Model.

Abstract

BACKGROUND: We had previously established an adequate cryopreservation process for hepatocyte spheroids for the development of an off-the-shelf bioartificial liver (BAL) system. The purpose of this study is to evaluate the efficacy of a BAL system containing cryopreserved immobilized porcine hepatocyte spheroids in a porcine model of acute liver failure (ALF). METHODS: ALF pigs were divided into three groups. The control group consisted of treatment-na&#xef;ve pigs (n&#x2009;=&#x2009;5), the blank group consisted of pigs that were attached to the BAL system not containing hepatocyte spheroids for 12&#x2009;h (n&#x2009;=&#x2009;5), and the BAL group consisted of pigs that were attached to the BAL containing hepatocyte spheroids for 12&#x2009;h (n&#x2009;=&#x2009;5). RESULTS: Analysis of specific oxygen uptake rates showed that the hepatocytes sustained vigorous activity throughout the 12-h period of BAL operation. Median survival time of pigs was 24.0&#x2009;h in the BAL group, 17.0&#x2009;h in the blank group, and 15.0&#x2009;h in the control group. The BAL group showed significantly prolonged survival according to Kaplan-Meier survival analysis compared to the blank group (p&#x2009;=&#x2009;0.04) and control group (p&#x2009;=&#x2009;0.04). Serum ammonia levels were significantly increased in the blank group (p&#x2009;<&#x2009;0.01) and control group (p&#x2009;<&#x2009;0.01), compared to the BAL group during the treatment period of the porcine ALF models. Prothrombin time (PT) was significantly lower in the BAL group compared to the blank group (p&#x2009;=&#x2009;0.04) and control group (p&#x2009;=&#x2009;0.01). CONCLUSIONS: A BAL system with a bioreactor containing cryopreserved immobilized hepatocyte spheroids showed effective clearance of serum ammonia, preservation of renal function, and improved survival in a porcine model of ALF.