Basic Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jun 21, 2021; 27(23): 3342-3356
Published online Jun 21, 2021. doi: 10.3748/wjg.v27.i23.3342
Conditioned secretome of adipose-derived stem cells improves dextran sulfate sodium-induced colitis in mice
Seunghun Lee, Jeonghoon Heo, Eun-Kyung Ahn, Jae Hyun Kim, Young-Ho Kim, Hee-Kyung Chang, Sang-Joon Lee, Jongsik Kim, Seun-Ja Park
Seunghun Lee, Department of Colorectal Surgery, Kosin University College of Medicine, Busan 49267, South Korea
Jeonghoon Heo, Eun-Kyung Ahn, Young-Ho Kim, Department of Molecular Biology and Immunology, Kosin University College of Medicine, Busan 49267, South Korea
Jae Hyun Kim, Seun-Ja Park, Department of Gastroenterology, Kosin University College of Medicine, Busan 49267, South Korea
Hee-Kyung Chang, Department of Pathology, Kosin University College of Medicine, Busan 49267, South Korea
Sang-Joon Lee, Department of Ophthalmology, Kosin University College of Medicine, Busan 49267, South Korea
Jongsik Kim, Department of Anatomy, Kosin University College of Medicine, Busan 49267, South Korea
Author contributions: Lee S, Ahn EK, Park SJ and Heo J designed the study; Lee S, Ahn EK, Chang HK, Kim J, Park SJ and Heo J performed the research; Lee S, Ahn EK, Kim JH, Kim YH, Lee SJ, Park SJ and Heo J participated in the interpretation of the data; Lee S, Ahn EK, Park SJ and Heo J wrote paper; Chang HK, Kim YH, Lee SJ, Kim J, Park SJ and Heo J supervised the analysis; all authors approved the final version.
Supported by National Research Foundation of Korea (NRF) grants funded by the Korea Government (MSIT), No. 2017R1A2B2011956 and No. 2019R1F1A1061453.
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the Institutional Animal Care and Use Committee at Kosin University College of Medicine (IACUC protocol number: Kosin15-12).
Conflict-of-interest statement: None of the authors have any conflicts of interest to declare.
Data sharing statement: No additional data are available.
ARRIVE guidelines statement: The authors have read the ARRIVE guidelines, and the manuscript was prepared and revised according to the ARRIVE guidelines.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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/
Corresponding author: Seun-Ja Park, MD, PhD, Professor, Department of Gastroenterology, Kosin University College of Medicine, 262 Gamcheon-ro, Seogu, Busan 49267, South Korea. parksj@kosinmed.or.kr
Received: February 4, 2021
Peer-review started: February 4, 2021
First decision: February 24, 2021
Revised: March 5, 2021
Accepted: May 19, 2021
Article in press: May 19, 2021
Published online: June 21, 2021
Processing time: 134 Days and 2.7 Hours
ARTICLE HIGHLIGHTS
Research background

Inflammatory bowel diseases (IBD) causing chronic and destructive inflammation of the gastrointestinal tract is mainly related to uncontrolled immune response. Current treatment for IBD using immunosuppressive agents is not successful for significant improvement in remission rates. It is necessary to develop effective, feasible and safe therapeutic strategy for IBD. Stem cells having the ability to regulate immune response have emerged as attractive therapeutic tools for incurable IBD.

Research motivation

Mesenchymal stem cells (MSCs) including adipose-derived stem cells (ADSCs) has been known as a promising therapeutic for IBD. However, the transplantation of MACSs in IBD patients showed inconsistent results because of their distinct differentiation and regenerative potential, and the variety of protocols for treatment. In addition, the therapeutic ability of MSCs is mostly mediated by their secretome including cytokines, chemokines, growth factor, and hormones. Therefore, it has been suggested that the MSCs secretome may have therapeutic potential for IBD treatment.

Research objectives

Although the immune-modulatory activity of ADSC is mediated by soluble paracrine factors, it is still unclear whether the therapeutic efficacy of soluble factors secreted from ADSCs is better than ADSCs themselves in inflammation-related diseases. Therefore, the purpose of this study was to investigate the effects of conditioned mouse ADSCs (mADSCs) secretome on colitis-induced mice.

Research methods

mADSCs were isolated from C57BL/6 mice (female, 8-10 wk-old) and identified using fluorescence-activated cell sorting. The conditioned mADSCs secretome was obtained by culturing mADSCs in serum-free medium with lipopolysaccharide (1 μg/mL) for 24 h, and characterized using a Proteome Profiler mouse cytokine array kit. For induction of mouse acute colitis, mice (C57BL/6. female, 8-wk-old) were supplied with 2% dextran sodium sulfate for 7 d and then normal drinking water for 4 d. Animals were divided into 4 groups, control (CON) group receiving normal drinking water during the experimental period, normal culture medium (NM) group receiving 100 μL normal culture medium three times (on 4, 6 and 8 d), mADSCs (SC) group receiving 1 × 105 cells/100 μL ADSCs once (on 4 d) and conditioned mADSCs secretome (CM) group receiving 100 μL mADSCs secretome three times (on days 4, 6, and 8). The length of the colon and histopatholgy of colon tissues were evaluated after sacrificing animals on 11 d. The mRNA expression levels of inflammatory cytokines in colon tissue were determined by quantitative real-time polymerase chain reaction assay, and the serum interleukin (IL)-6 levels were determined by enzyme-linked immunosorbent assay.

Research results

The isolated mADSCs maintained the mADSCs specific gene expression profiles during experiment. The conditioned mADSCs secretome obtained by culturing mADSCs with 1 μg/mL of lipopolysaccharides for 24 h contained high amounts of colony-stimulating factors, inflammatory chemokines and cytokines. The conditioned mADSCs secretome in dextran sulfate sodium (DSS)-induced mice ameliorated the loss of body weight and reduction of colon length, and improved the recovery of damaged colon tissue. The expression of IL-1b mRNA and IL-6 mRNA in colon tissues was significantly lower (P < 0.05) in the CM group than in the SC group (P < 0.05) and/or NM group (P < 0. 005). However, the expression level of tumor necrosis factor-α mRNAs in the NM and CM groups did not differ from that in the CON group. The concentration of serum IL-6 in DSS-induced mice was significantly lower in the CM group (5.94 pg/mL, P < 0.005) and the SC group (38.01 pg/mL, P < 0.05) than in NM group (207.40 pg/mL), which indicates that the conditioned mADSCs secretome suppressed the elevation of serum IL-6 concentration in DSS-induced mice.

Research conclusions

This study suggests that conditioned mADSCs secretome may inhibit the synthesis of pro-inflammatory cytokines in the damaged colon tissue, and reduce serum IL-6 Levels more effectively than mADSCs themselves in DSS-induced mice. This effective suppression of proinflammatory cytokines in colon tissue and serum might mainly contributes to the recovery of damaged colon tissue in DSS-induced mice, which suggests the therapeutic potential of the conditioned mADSCs secretome for IBD treatment.

Research perspectives

The conditioned mADSCs secretome may serve as a novel therapeutic tool for IBD. Therefore, it is needed to investigate the factors in conditioned mADSCs secretome involved in the effective regeneration of damaged colon tissue.