Hepatic Bioprinted Tissue Therapeutics Demonstrate Promise for the Treatment of Acute and Chronic Liver Diseases

Introduction: Acute liver failure (ALF) and Acute-on-chronic liver failure (ACLF) are treated with liver transplantation. Metabolic liver diseases such as phenylketonuria (PKU) and alpha-1-antitrypsin deficiency (A1ATD) can also be treated with liver transplantation. Due to the limited number of donor organs available, many patients are unable to receive a transplant. Transplant recipients are required to spend a lifetime on immune-suppressing drugs. Pediatric ALF has previously been treated via transplantation of isolated and encapsulated primary human hepatocytes (PHHs) with promising results. Herein we use Bioprinted Tissue Therapeutics (BTTs) containing PHHs and MSCs to rescue immune-competent mice with ALF and to explore the use of hepatic BTTs to treat chronic liver disease. Methods: Hepatic BTTs were created using Aspect Biosystems’ proprietary 3D bioprinting technology. BTTs are comprised of co-aggregated PHHs and MSCs suspended in a combination of solidified semi-permeable, immune-protective hydrogel biomaterials. ALF was induced via injection of CCl4 into immunocompetent mice. BTTs were implanted into either the intraperitoneal (IP) or subcutaneous (SubQ) space. Survival was recorded over 7 days. Healthy NSG mice were also implanted with BTTs to examine release of soluble A1AT. Blood was collected at regular intervals and livers were embedded for histology upon the completion of the study. Results: BTT treatment resulted in a survival rate of 78% (n=15) and 85% (n=7) in IP and SubQ implanted mice respectively, compared to 46% (IP, n=15) and 50% (SubQ, n=8) for mice receiving cell-free controls. SubQ implantation results were confirmed using PHHs from an alternate donor, wherein the survival rate for hepatic BTT-treated mice was 50% (n=8) compared to 13% for mice receiving cell-free controls. Combined the survival rate for hepatic BTT-treated mice was 68% vs 35% for mice receiving cell-free controls (P=0.003). Additionally, BTTs metabolized phenylalanine and produced A1AT. Conclusion: CCl4-induced ALF in immunocompetent mice can be successfully treated with hepatic BTTs containing primary human hepatocytes. Additionally, there is promise that this treatment could be used for chronic metabolic liver diseases. The high level of function of these devices suggests that they could be used to support liver function on an ongoing basis or to act as a bridge to transplantation or recovery. Our next step is to test a scaled up BTT for testing in rats for acute and chronic liver disease.