Comparison of in vivo immunomodulatory effects of intravenous and intraperitoneal administration of adipose-tissue mesenchymal stem cells in experimental autoimmune encephalomyelitis (EAE) Forouzan Yousefi a , Massoumeh Ebtekar a, ⁎, Masoud Soleimani c, ⁎⁎, Sara Soudi b , Seyed Mahmoud Hashemi b a Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran b Stem Cell Biology Department, Stem Cell Technology Research Center, Tehran, Iran c Department of Hematology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran abstract article info Article history: Received 18 April 2013 Received in revised form 14 July 2013 Accepted 29 July 2013 Available online 21 August 2013 Keywords: Mesenchymal stem cells Experimental autoimmune encephalomyelitis Immunomudulation Regulatory T cells Due to their immunomodulatory and anti-inflammatory competence, mesenchymal stem cells (MSCs) have been considered as a suitable candidate for treatment of autoimmune diseases. Earlier studies have shown that treatment with bone marrow-derived MSCs may modulate immune responses and reduce disease severity in ex- perimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Here we compare the immune regulatory properties of adipose tissue MSCs (AT-MSCs) in two independent routes of injection; namely intraperitoneal (IP) and intravenous (IV). We investigated the splenic CD4 + CD25 + FOXP3+ T cell population known as regulatory T cells, by flow cytometry and their brain cell infiltration by hematoxylin–eosin staining in both IP and IV routes of AT-MSC administration. We also evaluated the inflammatory cytokine profile including IFN-γ and IL-17 and anti-inflammatory cytokines such as IL-4 by ELISA technique in both routes of cell administration. We show that the IP route has a more pronounced effect in maintaining the splenic CD4 + CD25 + FOXP3+ T cell population and increase of IL-4 secretion. We also showed that IP injection of cells resulted in lower IFN-γ secretion and reduced cell infiltration in brain more effectively as compared to the IV route. The effects of AT-MSCs on down-regulation of splenocyte proliferation, IL-17 secretion and alleviat- ing the severity of clinical scores were similar in IP and IV routes. Our data show that, due to their immunomodulative and neuroprotective effects, AT-MSCs may be a proper candidate for stem cell based MS therapy. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Multiple sclerosis (MS) is a chronic autoimmune disease targeting the central nervous system (CNS), resulting in axonal pathology. Axonal lesions may lead to irreversible abrasions and contribute to disease se- verity [1–3]. Experimental autoimmune encephalomyelitis (EAE) is an alternative proper model for MS that is employed for investigating mechanisms of pathology and therapeutic approaches [4–6]. Stem cell therapy has gained attention in the field of treatment for neurodegener- ative diseases due to the self-renewing capacity of stem cells, their substantial proliferation and differentiation potentials [7–10]. Neural precursor cells, as a first candidate for therapeutic targets in neuro- inflammatory diseases, are considered as an optimum source but their application has been associated with certain limitations including harvesting, accessibility and low number of cells that can be used [11–13]. On other hand, embryonic stem cells are prone to forming ter- atomas due to their high potential for proliferation and differentiation, and may exhibit genetic anomalies in high passages. Their use is also limited by ethical issues and legal restrictions in certain countries [14–16]. Mesenchymal stem cells (MSCs) are a suitable candidate for cell therapy in neuroinflammatory diseases. They exert their anti- inflammatory and immunomodulatory effects via the suppression of T, B, NK and antigen presenting cells as well as their differentiation into neural-like and glial-like cells. Moreover, MSCs are less invasive in com- parison to other stem cells. As they are known to induce tolerance in im- mune cells, they do not pose the risk of malignancies, which may be induced by hematopoietic stem cell (HSC) transplantation. MSCs also produce different growth factors for promoting the angiogenesis and mitosis of neural stem cells. These factors can also promote oligodendrogenesis and inhibit astrogliosis. These effects are mediated by both cell–cell contact and soluble factors that foster the survival and proliferation of neural cells. MSCs also have been shown to affect the differentiation of T helper and Treg cells [17–23]. International Immunopharmacology 17 (2013) 608–616 ⁎ Correspondence to: M. Ebtekar, Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Ale-Ahmad Avenue, P.O. Box 14115-331, Tehran, Iran. ⁎⁎ Correspondence to: M. Soleimani, Department of Hematology, Faculty of Medical Sciences, Tarbiat Modares University, Ale-Ahmad Avenue, P.O. Box 14115-331, Tehran, Iran. E-mail addresses: ebtekarm@modares.ac.ir (M. Ebtekar), soleim_m@modares.ac.ir (M. Soleimani). 1567-5769/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.intimp.2013.07.016 Contents lists available at ScienceDirect International Immunopharmacology journal homepage: www.elsevier.com/locate/intimp