RESUMEN
Angiogenesis is considered to mediate the beneficial effects of mesenchymal cell therapy in spinal cord injury. After a moderate balloon-compression injury in rats, injections of either human adipose tissue-derived stromal/stem cells (hADSCs) or their conditioned culture media (CM-hADSC) elicited angiogenesis around the lesion site. Both therapies increased vascular density, but the presence of hADSCs in the tissue was required for the full maturation of new blood vessels. Only animals that received hADSC significantly improved their open field locomotion, assessed by the BBB score. Animals that received CM-hADSC only, presented haemorrhagic areas and lack pericytes. Proteomic analyses of human angiogenesis-related factors produced by hADSCs showed that both pro- and anti-angiogenic factors were produced by hADSCs in vitro, but only those related to vessel maturation were detectable in vivo. hADSCs produced PDGF-AA only after insertion into the injured spinal cord. hADSCs attracted resident pericytes expressing NG2, α-SMA, PDGF-Rß and nestin to the lesion, potentially contributing to blood vessel maturation. We conclude that the presence of hADSCs in the injured spinal cord is essential for tissue repair.
Asunto(s)
Medios de Cultivo Condicionados/farmacología , Trasplante de Células Madre Mesenquimatosas/métodos , Células Madre Mesenquimatosas/citología , Pericitos/citología , Traumatismos de la Médula Espinal/terapia , Animales , Vasos Sanguíneos/efectos de los fármacos , Vasos Sanguíneos/fisiología , Barrera Hematoencefálica , Movimiento Celular , Medios de Cultivo Condicionados/química , Endotelio Vascular/citología , Femenino , Hemorragia/sangre , Hemorragia/terapia , Humanos , Inyecciones Espinales , Neovascularización Fisiológica/genética , Nestina/metabolismo , Ratas Sprague-Dawley , Traumatismos de la Médula Espinal/patologíaRESUMEN
Cell therapy is a promising strategy to pursue the unmet need for treatment of spinal cord injury (SCI). Although several studies have shown that adult mesenchymal cells contribute to improve the outcomes of SCI, a description of the pro-regenerative events triggered by these cells is still lacking. Here we investigated the regenerative properties of human adipose tissue derived stromal cells (hADSCs) in a rat model of spinal cord compression. Cells were delivered directly into the spinal parenchyma immediately after injury. Human ADSCs promoted functional recovery, tissue preservation, and axonal regeneration. Analysis of the cord tissue showed an abundant deposition of laminin of human origin at the lesion site and spinal midline; the appearance of cell clusters composed of neural precursors in the areas of laminin deposition, and the appearance of blood vessels with separated basement membranes along the spinal axis. These effects were also observed after injection of hADSCs into non-injured spinal cord. Considering that laminin is a well-known inducer of axonal growth, as well a component of the extracellular matrix associated to neural progenitors, we propose that it can be the paracrine factor mediating the pro-regenerative effects of hADSCs in spinal cord injury.
Asunto(s)
Tejido Adiposo/citología , Laminina/metabolismo , Células Madre Mesenquimatosas/citología , Regeneración Nerviosa , Traumatismos de la Médula Espinal/patología , Animales , Astrocitos/citología , Conducta Animal , Células Endoteliales/citología , Matriz Extracelular/metabolismo , Femenino , Humanos , Inflamación , Trasplante de Células Madre Mesenquimatosas , Neuronas/citología , Ratas , Ratas Sprague-Dawley , Regeneración , Médula Espinal/patología , Traumatismos de la Médula Espinal/metabolismoRESUMEN
Regeneration of spinal cord injury (SCI) is a major topic of biomedical research. Laminin is an extracellular matrix protein implicated in neural development and regeneration, but despite that, there are no reports of exogenous laminin contributing to improve the outcome of experimental SCI. Here we investigated whether a biomimetic polymer of laminin assembled on pH acidification, henceforth called polylaminin, could be used to treat SCI in rats. Acute local injection of polylaminin, but not of nonpolymerized laminin, improved motor function after thoracic compression, partial or complete transection. In the latter case, the BBB score for open field locomotion 8 wk after lesion increased from 4.2 ± 0.48 to 8.8 ± 1.14 in animals treated with polylaminin of human origin. Accordingly, neurons retrogradely labeled from the sublesion stump were detected in the spinal cord and brain stem, indicating regrowth of short and long fibers across a complete transection. Polylaminin also played an unsuspected anti-inflammatory role, which underlies the early onset of its positive effects on locomotion from the first week after treatment. The beneficial effects of polylaminin were not observed in animals treated with the nonpolymerized protein or vehicle only. We propose that polylaminin is a promising therapeutic agent to treat human SCI.