Elsevier

Neuroscience

Volume 335, 29 October 2016, Pages 221-231
Neuroscience

Intravenous infusion of mesenchymal stem cells promotes functional recovery in a model of chronic spinal cord injury

https://doi.org/10.1016/j.neuroscience.2016.08.037Get rights and content

Highlights

  • IV infusion of MSCs in the chronic phase of SCI improved locomotor function.

  • Some infused MSCs distributed to the injured spinal cord.

  • IV MSC infusion rapidly reduced intravenous dye leakage into the injured spinal cord.

  • RECA-1 and PDGFR β positive microvasculature was more prevalent in the MSC-group.

  • MSC-group showed greater anatomical repair in the chronic SCI.

Abstract

Intravenous infusion of mesenchymal stem cells (MSCs) derived from adult bone marrow improves behavioral function in rat models of spinal cord injury (SCI). However, most studies have focused on the acute or subacute phase of SCI. In the present study, MSCs derived from bone marrow of rats were intravenously infused 10 weeks after the induction of a severe contusive SCI. Open field locomotor function was assessed weekly until 20 weeks post-SCI. Motor recovery was greater in the MSC-treated group with rapid improvement beginning in earlier post-infusion times than in the vehicle-treated group. Blood spinal cord barrier (BSCB) integrity was assessed by the intravenous infusion of Evans Blue (EvB) with spectrophotometric quantitation of its leakage into the parenchyma. In MSC-treated rats, BSCB leakage was reduced. Immunohistochemical staining for RECA-1 and PDGFR-β showed increased microvasculature/repair-neovascularization in MSC-treated rats. There was extensive remyelination around the lesion center and increased sprouting of the corticospinal tract and serotonergic fibers after MSC infusion. These results indicate that the systemic infusion of MSCs results in functional improvement that is associated with structural changes in the chronically injured spinal cord including stabilization of the BSCB, axonal sprouting/regeneration and remyelination.

Introduction

There are approximately 5.3 million people living with the consequences of spinal cord injury (SCI) worldwide (Wyndaele and Wyndaele, 2006, van den Berg et al., 2010, Piltti et al., 2013). Local and segment-limited primary damage to the spinal cord is characterized by the rupture or contusion of axons and the subsequent development of hemorrhage, ischemia, and edema. The damaged area expands considerably during the first weeks due to secondary damage to neuronal and glial cells. The combination of primary and secondary damage results in necrosis with tissue loss and chronic paralysis with sensorimotor disturbances (Schwab et al., 2006).

A promising cell-based therapy in the treatment of SCI using mesenchymal stem cells (MSCs) is currently being investigated. However, most studies have focused on the acute phase of SCI (Tetzlaff et al., 2011). In an acute model of rodent SCI, direct transplantation of MSCs enhances functional recovery, promotes axonal regeneration, reduces lesion size and protects the corticospinal tract (CST) (Sasaki et al., 2009). Intravenous infusion of MSCs also improves functional outcome after acute (Quertainmont et al., 2012, Matsushita et al., 2015) and acute/subacute (Osaka et al., 2010) contusive SCI. However, there are a limited number of studies evaluating treatment efficacy during the chronic phase of SCI (Tetzlaff et al., 2011). It is an important clinical and research issue to develop approaches to provide therapeutic efficacy in chronic SCI.

In this study MSCs derived from bone marrow were intravenously delivered at 10 weeks after SCI to investigate whether systemic injections improve functional outcome after contusive chronic SCI. Evaluation of the behavioral outcome, histological changes, blood spinal cord barrier (BSCB) disruption, remyelination and sprouting of descending axon tracts were performed to study the structural and functional changes after MSC infusion in a model of chronic SCI in rats.

Section snippets

Experimental procedures

All experiments were carried out in accordance with the National Institute of Health Guide for the Care and Use of Laboratory Animals (NIH Publication No. 80-23, revised 1996) and the institutional guidelines in Sapporo Medical University. The use of animals in this study was approved by the Animal Care and Use Committee of Sapporo Medical University. All methods and data were reported in accordance with guidelines provided by Animals in Research: Reporting in Vivo Experiments (ARRIVE) and

Behavioral analysis of locomotor function

Open field locomotor activity was assessed with the BBB scoring scale at 2 days before and weekly up to 20 weeks after SCI induction (Fig. 1). Before SCI induction, BBB scores had a value of 21. All animals demonstrated near-complete hind limb paraplegia immediately after SCI and then exhibited a gradual improvement that plateaued 6 weeks after injury. To examine whether infused MSCs improved functional outcome after chronic SCI, we randomized the rats and performed intravenous administration of

Discussion

In the present study, we demonstrated that intravenous administration of MSCs in the chronic phase of a severe contusive SCI model in the rat improved locomotor function. A precise definition of the chronic phase of SCI has not been established (Piltti et al., 2013). In our model, a severe contusive SCI was induced and spontaneous motor recovery was observed over several weeks. Spontaneous recovery peaked at about 6 week’s post-SCI and reached a persistent plateau. We chose 10 weeks after SCI as

Conclusion

In summary, intravenous infusion of MSCs resulted in improved locomotor function in chronic and severe SCI model in rats. There was a therapeutic effect of MSC administration even when administered 10 weeks after SCI induction. The therapeutic mechanisms include attenuation of BSCB disruption, sprouting and regeneration and remyelination of fiber tracts in the injured spinal cord. Thus, a cell-based MSC therapy may have therapeutic value in not only the acute phase following SCI, but also the

Acknowledgments

This work was supported in part by JSPS KAKENHI, Japan grant Numbers 26462213, 24890181, 25462227, 25462226, 16K10794, the AMED Translational Research Network Program (B51), the RR&D Service of U.S. Department of Veterans Affairs (B7335R, B9260L), the National Multiple Sclerosis Society (RG2135), and the Connecticut (CT) Stem Cell Research Program (12-SCB-Yale-05). We are thankful to the National BioResource Project – Rat (http://www.anim.med.kyoto-u.ac.jp/NBR/) for providing this strain of rat

References (52)

  • M. Osaka et al.

    Intravenous administration of mesenchymal stem cells derived from bone marrow after contusive spinal cord injury improves functional outcome

    Brain Res

    (2010)
  • C.A. Ruff et al.

    Cell-based transplantation strategies to promote plasticity following spinal cord injury

    Exp Neurol

    (2012)
  • M. Sasaki et al.

    Remyelination of the injured spinal cord

    Prog Brain Res

    (2007)
  • J.M. Schwab et al.

    Experimental strategies to promote spinal cord regeneration–an integrative perspective

    Prog Neurobiol

    (2006)
  • J. Suzuki et al.

    Bilateral cortical hyperactivity detected by fMRI associates with improved motor function following intravenous infusion of mesenchymal stem cells in a rat stroke model

    Brain Res

    (2013)
  • A. Takayanagi et al.

    Intravenous preload of mesenchymal stem cells rescues erectile function in a rat model of cavernous nerve injury

    J Sex Med

    (2015)
  • W. Zheng et al.

    Therapeutic benefits of human mesenchymal stem cells derived from bone marrow after global cerebral ischemia

    Brain Res

    (2010)
  • Y. Akiyama et al.

    Remyelination of the spinal cord following intravenous delivery of bone marrow cells

    Glia

    (2002)
  • Y. Akiyama et al.

    Remyelination of the rat spinal cord by transplantation of identified bone marrow stromal cells

    J Neurosci

    (2002)
  • A.R. Alexanian et al.

    Transplanted neurally modified bone marrow-derived mesenchymal stem cells promote tissue protection and locomotor recovery in spinal cord injured rats

    Neurorehabil Neural Repair

    (2011)
  • A. Armulik et al.

    Pericytes regulate the blood–brain barrier

    Nature

    (2010)
  • S.P. Bandaru et al.

    Dendritic spine dysgenesis contributes to hyperreflexia after spinal cord injury

    J Neurophysiol

    (2015)
  • D.M. Basso et al.

    A sensitive and reliable locomotor rating scale for open field testing in rats

    J Neurotrauma

    (1995)
  • E.J. Bradbury et al.

    Chondroitinase ABC promotes functional recovery after spinal cord injury

    Nature

    (2002)
  • W.B.J. Cafferty et al.

    The Nogo–Nogo receptor pathway limits a spectrum of adult CNS axonal growth

    J Neurosci

    (2006)
  • S.J.A. Davies et al.

    Transplantation of specific human astrocytes promotes functional recovery after spinal cord injury

    PLoS One

    (2011)
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