Basic Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. Feb 27, 2018; 10(2): 287-296
Published online Feb 27, 2018. doi: 10.4254/wjh.v10.i2.287
Multipotent stromal cells stimulate liver regeneration by influencing the macrophage polarization in rat
Andrey Elchaninov, Timur Fatkhudinov, Natalia Usman, Irina Arutyunyan, Andrey Makarov, Anastasia Lokhonina, Irina Eremina, Viktor Surovtsev, Dmitry Goldshtein, Galina Bolshakova, Valeria Glinkina, Gennady Sukhikh
Andrey Elchaninov, Timur Fatkhudinov, Natalia Usman, Irina Arutyunyan, Andrey Makarov, Anastasia Lokhonina, Gennady Sukhikh, National Medical Research Center for Obstetrics, Gynecology and Perinatology named after Academician V.I.Kulakov of Ministry of Healthcare of Russian Federation, Moscow 117997, Russia
Andrey Elchaninov, Timur Fatkhudinov, Anastasia Lokhonina, Irina Eremina, Viktor Surovtsev, Peoples Friendship University of Russia (RUDN University), Moscow 117198, Russia
Irina Arutyunyan, Galina Bolshakova, Scientific Research Institute of Human Morphology, Moscow 117418, Russia
Andrey Makarov, Valeria Glinkina, Pirogov Russian National Research Medical University, Ministry of Healthcare of the Russian Federation, Moscow 117997, Russia
Dmitry Goldshtein, Research Center of Medical Genetics, Moscow 115478, Russia
Author contributions: Elchaninov A and Fatkhudinov T contributed to study conception and design; Elchaninov A, Usman N and Arutyunyan I contributed to data acquisition, data analysis and interpretation; Elchaninov A, Makarov A, Lokhonina A, Eremina I, Surovtsev V, Goldshtein D, Bolshakova G, Glinkina V and Sukhikh G contributed to data acquisition, data analysis and interpretation; Elchaninov A, Fatkhudinov T and Usman N contributed to editing, reviewing and final approval of article.
Supported by Russian Science Foundation, No. 17-15-01419.
Institutional review board statement: The study was approved by the Ethical Review Board at the Scientific Research Institute of Human Morphology, Protocol No. 16, November 19, 2015 (Moscow, Russian Federation).
Institutional animal care and use committee statement: All experimental work involving animals was carried out according to the standards of laboratory practice (National Guidelines No.267 by Ministry of Healthcare of the Russian Federation.
Conflict-of-interest statement: The authors do not have any commercial or other association that might pose a conflict of interest.
Data sharing statement: No additional data are available.
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: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Timur Fatkhudinov, DSc, MD, PhD, Academic Research, Laboratory of Regenerative Medicine, National Medical Research Center for Obstetrics, Gynecology and Perinatology named after Academician V.I.Kulakov of Ministry of Healthcare of Russian Federation, 4 Oparina Street, Moscow 117997, Russia. tfat@yandex.ru
Telephone: +7-903-2561157 Fax: +7-495-4388507
Received: September 18, 2017
Peer-review started: September 20, 2017
First decision: October 31, 2017
Revised: October 31, 2017
Accepted: February 5, 2018
Article in press: February 5, 2018
Published online: February 27, 2018
Processing time: 167 Days and 0.5 Hours
ARTICLE HIGHLIGHTS
Research background

The resulting post-hepatectomy liver failure is a major manifestation of the small-for-size liver remnant syndrome, when the critically reduced liver mass is insufficient to maintain normal liver function. The problem can be solved by some specific controllable stimulation of compensatory growth combined with intensive liver care and management for acute hepatic failure. Multipotent stromal cells may therefore represent a reasonable choice not only in cases of extensive hepatectomy but also for other types of severe liver damage (e.g. cirrhosis). Multipotent stromal cells are found to be a helpful supplement in various repair processes in mammals, particularly in solid organs. These cells are considered as a promising tool of regenerative medicine. Their ability to stimulate reparative regeneration of damaged liver has been confirmed, but the mechanisms remain uncertain.

Research motivation

The experimentally proven enhancement of liver regeneration by multipotent stromal cells (MSCs) must be essentially paracrine, because their transplantation to residual livers causes an increase in concentrations of HGF and several other growth factors within the regenerating tissues. Therapeutic activity of MSCs is apparently related to their anti-inflammatory properties, which also represent a sort of paracrine regulation, as manifested by a local increase in IL-4, IL-13, and TSG-6 production paralleled by relative shortage of TNFα and IL-6. Modulation of inflammatory reactions may be implemented via influence of these, or similar, paracrine factors on immune cells, especially on macrophages. Several studies, however, confirm the ability of MSCs to differentiate into hepatocytes, which leads to quite a different explanation for the positive influence of MSCs on liver repair.

Research objectives

In our experiments we found that intrasplenic allogeneic transplantation of the umbilical cord-derived multipotent stromal cells stimulated hepatocyte proliferation and organ mass recovery after subtotal resection. These effects may result from positive paracrine influence of the transplanted cells on polarization of the liver resident macrophages to M2 phenotype.

Research methods

The MSCs were obtained from the intervascular tissue of umbilical cords, dissected from rat fetuses, by the explant culture technique. The vital labeling of MSCs with РКН26 was carried out on the 3rd passage. The subtotal resection was performed on male Sprague-Dawley rats. The experimental group animals received a transplant 106 MSCs infused into the spleen. Hepatocyte proliferation was assessed by counting of either mitotic figures or Ki67-positive cells in microscopic images. MSC differentiation was assessed with antibodies to hepatocyte-specific marker cytokeratin 18 (CK18), cholangiocyte-specific protein CK19, smooth muscle cell-specific protein α-SMA, the endothelial cell marker CD31, or the active fibroblast marker FAPα. Total macrophages of the liver were selectively stained in cryosections incubated with anti-CD68 antibodies (1:100, Abcam), while the M2a and M2c macrophage populations were selectively stained with anti-CD206 antibodies. Expression of interleukin and growth factor genes was evaluated with PCR-RT.

Research results

Intrasplenic allogeneic transplantation of the umbilical cord-derived multipotent stromal cells stimulates reparative processes within the residual liver tissue after subtotal resection (removal of 80% of the organ mass), as indicated by increased rates of hepatocyte proliferation and accelerated organ mass recovery. These effects may result from paracrine influence of the transplanted cells on the resident macrophage population of the liver. The transplantation favors polarization of macrophages to M2 phenotype (the M2-polarized macrophages specifically express CD206; they are known to suppress inflammation and support tissue repair). No differentiation of the transplanted cells into any of the liver cell types have been observed in the study.

Research conclusions

In this study we observed a stimulating effect of the umbilical cord-derived MSCs on liver regeneration after subtotal resection in rats, manifested as increased survival of the operated animals, increased rates of liver mass recovery, and increased proliferation activity of hepatocytes. We found no direct evidence for the paracrine effect of MSCs on liver regeneration after the subtotal liver resection in rats. However, the paracrine mechanism of the therapeutic activity of transplanted MSC is indirectly indicated by a decrease in the total number of CD68 + macrophages and an increase in the proportion of M2 pro-repair macrophages in the regenerating liver as compared to animals in which the transplantation was only mimicked.

Research perspectives

Exact molecular mechanisms of the paracrine effect of MSC transplantation on hepatocyte proliferation and liver macrophage behavior in the aftermath of subtotal liver resection remain unclear. Further studies in this direction are very desirable, since any possibility of controlling hepatocyte proliferation and/or liver macrophage polarization could be of great therapeutic importance, especially in severe liver injuries.