Basic Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. Oct 27, 2018; 10(10): 719-730
Published online Oct 27, 2018. doi: 10.4254/wjh.v10.i10.719
Experimental bio-artificial liver: Importance of the architectural design on ammonia detoxification performance
María Dolores Pizarro, María Eugenia Mamprin, Lucas Damián Daurelio, Joaquín Valentín Rodriguez, María Gabriela Mediavilla
María Dolores Pizarro, María Eugenia Mamprin, Lucas Damián Daurelio, Joaquín Valentín Rodriguez, María Gabriela Mediavilla, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Rosario S2002 LRK, Argentina
María Dolores Pizarro, Lucas Damián Daurelio, Laboratorio de Investigaciones en Fisiología y Biología Molecular Vegetal (LIFiBVe), Facultad de Ciencias Agrarias, Universidad Nacional del Litoral, Esperanza 3080, Argentina
María Eugenia Mamprin, Farmacología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario S2002 LRK, Argentina
Joaquín Valentín Rodriguez, Centro Binacional de Criobiología Clínica y Aplicada (CAIC), Universidad Nacional de Rosario, Rosario S2011 BXN, Argentina
María Gabriela Mediavilla, Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Consejo Nacional de Investigaciones Científicas y Tecnológicas, y Universidad Nacional de Rosario, Rosario S2002 LRK, Argentina
Author contributions: Pizarro MD performed the majority of experiments, analyzed data, and wrote the manuscript; Mamprin ME and Mediavilla MG designed the research, contributed new reagents, analyzed data, and wrote the manuscript; Daurelio LD designed and supervised the statistical analysis; Rodriguez JV developed the cylindrical bioreactor and metabolite mass balance equations, performed a critical revision, and contributed to the research and the redaction of this article; all the authors were involved in reviewing the literature for latest contributions in the field, writing, and editing the manuscript; Mamprin ME and Mediavilla MG have equally contributed to this work.
Supported by Universidad Nacional de Rosario (UNR), BIO 272, Resol. C.S., No. 677/2013; Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT), PICT-03-14492, BID 1728 OC/AR (Argentina); and a grant from Regione Autonoma Friuli-Venezia Giulia, Italy.
Institutional review board statement: The study was reviewed and approved by the National University of Rosario Institutional Review Board (Resol. C.S. No. 677/2013).
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the Institutional Animal Care and Use Committee of the Faculty of Biochemical and Pharmaceutical Sciences-UNR (Resol. No. 139/2011).
Conflict-of-interest statement: No potential conflicts of interest relevant to this article were reported.
Open-Access: This article is an open-access article, which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Correspondence to: María Gabriela Mediavilla, PhD, Associate Researcher, Doctor, Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Consejo Nacional de Investigaciones Científicas y Tecnológicas, y Universidad Nacional de Rosario, Suipacha 531, Rosario S2002 LRK, Argentina.
Telephone: +54-341-4350661 Fax: +54-341-4390465
Received: May 22, 2018
Peer-review started: May 23, 2018
First decision: June 14, 2018
Revised: July 12, 2018
Accepted: August 6, 2018
Article in press: August 7, 2018
Published online: October 27, 2018
Research background

Liver failure is a condition that usually requires liver transplantation, but in some cases acute liver failure resolves spontaneously due to the viable hepatic mass remaining after the cause of the damage has disappeared. If the amount of this functional tissue has the sufficient capacity to handle the detoxification of harmful metabolites produced by the insult and to provide the needed essential hepatic molecules and factors, then the regeneration capacity of the organ allows the recovery. This is why many attempts have been pursued to help the patient´s liver to pass through this acute failure and either recover or extend the time frame for a liver transplantation. Artificial livers, either dialysis based or incorporating hepatic cells and tissues (these later referred to as bio-artificial livers or BALs), are extracorporeal devices intended to aid the failing livers to overcome failure or at least to permit the patient to improve to undergo transplantation. In this sense, BALs are considered the choice to accomplish this job but until now they have been applied only by medical care teams that are able to obtain the biological component and to assemble the device at the same location making the practice limited to very few centers in the world.

Research motivation

The BAL research field is several decades old but still no successful device has been developed. Several prototypes have been submitted to clinical trials but none are routinely used in clinical settings or commercially available. These prototypes use isolated cells of hepatic origin (isolated primary human or pig hepatocytes and HepG2/C3A cell line), which is a biological material that requires expertise and money to be obtained and/or maintained. Additionally, cryopreservation of primary hepatocytes is not a very successful technique and recovery after thawing is poor. Among other researchers in the field, we propose and are testing the use of liver microorgans (LMOs) as the biological component for BAL devices, which are promising in terms of bearing all hepatic cellular types and microarchitecture and involve a simple method to obtain. These characteristics are appealing because they bring the possibility of using procured organs not suitable for transplantation to get the material necessary to feed pre-assembled cartridges at the same centers were the BAL would be needed. Our experience in the field has taught us that changes in the artificial part of these devices can have an impact on the biological component function. The finding that these changes in design, that can be minor or significant, have an influence on performance with effects ranging from subtle to massive, address the importance of finely tuning the interplay between the components of the device to optimize BAL operation.

Research objectives

LMOs failed to detoxify ammonia in a scaled-up BAL configuration that was previously successful. We set out to solve this problem and analyze the possible reasons of the phenomenon we were observing.

Research methods

The methodology used is the standard in our laboratory and has been previously published. The novelty is to perform and report the comparison of different BAL designs using the same biological component. This is the first report making such a comparison in the same set of experiments using cells and tissues from the same brood of experimental animals, same batches of solutions, same laboratory instruments, same materials to construct the devices, and so forth.

Research results

The main result we achieved in this work is that LMOs were totally incompetent to detoxify ammonia when placed in a cylindrical shaped BAL while they were fully able to detoxify ammonia inside a flat bottomed BAL.

Research conclusions

The accumulation of high levels of ammonia in the blood is an important issue in patients presenting liver failure, and is of the highest interest when studying this kind of device. In the literature, we have always found comparisons of different BALs only in review articles that use data from different research groups, which renders the comparative analysis incomplete. Our experimental design makes our comparison coherent and valid, and strongly demonstrates that the architecture of BALs can determine the success of this kind of device.

Research perspectives

We consider that this is an especially important finding, particularly in the light of the results presented, compelling future research to put an effort to finely tune the interplay between the artificial and biological components of BALs in order to achieve optimal performance and finally reach the clinical setting.