SCIENCE CHINA Life Sciences • RESEARCH PAPER •
doi: 10.1007/s11427-016-9002-6
Human placenta-derived mesenchymal stem cells loaded on linear ordered collagen scaffold improves functional recovery after completely transected spinal cord injury in canine Sufang Han1†, Zhifeng Xiao1†, Xing Li1†, Huan Zhao2, Bin Wang1, Zhixue Qiu2, Zhi Li2, Xin Mei2, Bai Xu3, Caixia Fan3, Bing Chen1, Jin Han1, Yanzheng Gu2, Huilin Yang2, Qin Shi2* & Jianwu Dai1** 1
State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100080, China; 2 Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopaedic Institute, Soochow University, Suzhou 215006, China; 3 Key Laboratory for Nano-Bio Interface Research, Division of Nanobiomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China Received November 8, 2016; accepted January 10, 2017; published online May 16, 2017
Traumatic spinal cord injury (SCI) is a major challenge in the clinic. In this study, we sought to examine the synergistic effects of linear ordered collagen scaffold (LOCS) and human placenta-derived mesenchymal stem cells (hPMSCs) when transplanted into completely transected beagle dogs. After 36 weeks observation, we found that LOCS+hPMSCs implants promoted better hindlimb locomotor recovery than was observed in the non-treatment (control) group and LOCS group. Histological analysis showed that the regenerated tissue after treatment was well integrated with the host tissue, and dramatically reduced the volume of cystic and chondroitin sulfate proteoglycans (CSPGs) expression. Furthermore, the LOCS+hPMSCs group also showed more neuron-specific βIII-tubulin (Tuj-1)- and NeuN-positive neurons in the lesion area, as well as axonal regeneration, remyelination and synapse formation in the lesion site. Additionally, dogs in the LOCS+hPMSCs group experienced enhanced sprouting of both ascending (CGRP-positive) sensory fibers and descending (5-HT- and TH-positive) motor fibers at the lesion area. All these data together suggested that the combined treatment had beneficial effects on neuronal regeneration and functional improvement in a canine complete transection model. Therefore, LOCS+hPMSCs implantation holds a great promise for bridging the nerve defect and may be clinically useful in the near future. spinal cord injury, hPMSCs, LOCS, canine, regeneration Citation:
Han, S., Xiao, Z., Li, X., Zhao, H., Wang, B., Qiu, Z., Li, Z., Mei, X., Xu, B., Fan, C., Chen, B., Han, J., Gu, Y., Yang, H., Shi, Q., and Dai, J. (2017). Human placenta-derived mesenchymal stem cells loaded on linear ordered collagen scaffold improves functional recovery after completely transected spinal cord injury in canine. Sci China Life Sci 60. doi: 10.1007/s11427-016-9002-6
†Contributed equally to this work *Corresponding author (email:
[email protected]) **Corresponding author (email:
[email protected])
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Han, S., et al.
INTRODUCTION Traumatic spinal cord injury (SCI) results in the disruption of ascending and descending axons, leading to severe sensory, motor, and autonomic nerve deficits below the level of injury (Thuret et al., 2006). SCIs often cause permanent functional impairments, such as paraplegia and quadriplegia, which seriously affect quality of life and pose a significant economic burden on patients (Anderson, 2004). However, there are no therapeutic methods with robust effects available for clinical use (Olson, 2013). Repairing SCIs has been a hot issue for both medicine and neuroscience. In recent years, extensive interventions involving the administration of growth-promoting trophic factors, neutralization of inhibitory molecules, and use of cell or biomaterial scaffolds have been considered to facilitate the creation of a permissive environment in injured spinal cords (Hollis and Tuszynski, 2011; Shrestha et al., 2014; Thuret et al., 2006). Stem cell-based transplantation therapy has been proven to be a potentially powerful tool for repairing SCIs (AssuncaoSilva et al., 2015; Dong et al., 2015). Among various stem cells, mesenchymal stem cells (MSCs) have been intensively studied because of their pluripotency, easy availability, and low immunogenicity (Chamberlain et al., 2007; Di Nicola et al., 2002; Jiang et al., 2002). Furthermore, the paracrine and immunomodulatory properties of MSCs are considered to ameliorate the SCI microenvironment (D’Souza et al., 2015). The MSCs we used in this study were derived from human term placentas, which are usually discarded after childbirth, and are therefore more easily obtainable and involve no ethical concerns (Fukuchi et al., 2004; Yen et al., 2005). However, in the case of large lesions, the regenerated axonal fibers could not cross the physical gap. A growing number of studies are currently focused on the development of bioengineered scaffolds to bridge the lesion cavities and support tissue restoration (Pires and Pêgo, 2015; Straley et al., 2010; Wang et al., 2011). An ideal scaffold would include the following properties: (i) good biocompatibility, low immunogenicity and suitable biodegradability when implanted in vivo; (ii) suitable mechanical properties for cell adhesion and axonal regeneration; and (iii) the ability to provide guidance to the regenerating axons (Ji et al., 2014; Straley et al., 2010). In our previous studies, we developed a LOCS, a linear-ordered collagen scaffold, which showed excellent biocompatibility, and its linear-ordered structure could effectively orient and guide regenerating axons (Cao et al., 2011). In addition, the LOCS also acted as a backbone to carry biologically active molecules, such as neurotrophic factors and the antagonists to the myelin-associated inhibitors (Han et al., 2010; Shi et al., 2014). Therefore, in this study, we tried to evaluate the synergistic effects of grafting a LOCS combined with hPMSCs (LOCS+hPMSCs) on the restoration of function in a canine T8 completely transected spinal cord. After 36 weeks of
observation, our data showed that the LOCS+hPMSCs implant ameliorated the hostile microenvironment of the injured spinal cord and effectively facilitated axonal regeneration and functional recovery after spinal cord injury.
RESULTS LOCS+hPMSCs promoted locomotor functional recovery after SCI In this study, we evaluated hindlimb function by Olby score, which was able to accurately quantify the extent of recovery of the dogs following SCI. The dogs had normal motor function before SCI (Olby score=14), but immediately after SCI, the hindlimbs of all of the experimental dogs had no voluntary hindlimb movement and dragged passively (Olby score=0). As shown in Figure 1, after 36 weeks of recovery, the dogs in the control group reached a plateau, with an average score of (5.0±0.35), which indicated that three joints of the hindlimbs had extensive movement but there was no weight-bearing protraction of the pelvic limb (Movie S1 in Supporting Information). In contrast, dogs in the LOCS (Movie S2 in Supporting Information) and LOCS+hPMSCs group (Movie S3 in Supporting Information) could support their weight using the hindlimbs, and dogs in the LOCS+hPMSCs group showed the most improvement in locomotor function. In the LOCS+hPMSCs group, unassisted standing on the hindlimbs was noticed in one dog at the 8th week, and half of the dogs could stand or walk unassisted from the 16th week. Furthermore, the Olby scores in the LOCS+hPMSCs group were higher than those in the LOCS group at all indicated time points, and the differences between the two groups were significant at weeks four and eight. LOCS+hPMSCs reduced cystic cavities and the expression of chondroitin sulfate proteoglycans (CSPGs) We examined the histopathological changes of the injured
LOCS+hPMSCs Figure 1 implants promoted locomotor functional recovery in canine SCIs. Hindlimb locomotor scores as assessed by the Olby score. *, P
