Taking central nervous system regenerative therapies to the clinic: curing rodents versus nonhuman primates versus humans

The central nervous system is known to have limited regenerative capacity.Not only does this halt the human body’s reparative processes after central nervous system lesions,but it also impedes the establishment of effective and safe therapeutic options for such patients.Despite the high prevalence of stroke and spinal cord injury in the general population,these conditions remain incurable and place a heavy burden on patients’families and on society more broadly.Neuroregeneration and neural engineering are diverse biomedical fields that attempt reparative treatments,utilizing stem cells-based strategies,biologically active molecules,nanotechnology,exosomes and highly tunable biodegradable systems(e.g.,certain hydrogels).Although there are studies demonstrating promising preclinical results,safe clinical translation has not yet been accomplished.A key gap in clinical translation is the absence of an ideal animal or ex vivo model that can perfectly simulate the human microenvironment,and also correspond to all the complex pathophysiological and neuroanatomical factors that affect functional outcomes in humans after central nervous system injury.Such an ideal model does not currently exist,but it seems that the nonhuman primate model is uniquely qualified for this role,given its close resemblance to humans.This review considers some regenerative therapies for central nervous system repair that hold promise for future clinical translation.In addition,it attempts to uncover some of the main reasons why clinical translation might fail without the implementation of nonhuman primate models in the research pipeline.

Disease modifying treatment of spinal cord injury with directly reprogrammed neural precursor cells in non-human primates

BACKGROUND The development of regenerative therapy for human spinal cord injury(SCI)is dramatically restricted by two main challenges:the need for a safe source of functionally active and reproducible neural stem cells and the need of adequate animal models for preclinical testing.Direct reprogramming of somatic cells into neuronal and glial precursors might be a promising solution to the first challenge.The use of non-human primates for preclinical studies exploring new treatment paradigms in SCI results in data with more translational relevance to human SCI.AIM To investigate the safety and efficacy of intraspinal transplantation of directly reprogrammed neural precursor cells(drNPCs).METHODS Seven non-human primates with verified complete thoracic SCI were divided into two groups:drNPC group(n=4)was subjected to intraspinal transplantation of 5 million drNPCs rostral and caudal to the lesion site 2 wk post injury,and lesion control(n=3)was injected identically with the equivalent volume of vehicle.RESULTS Follow-up for 12 wk revealed that animals in the drNPC group demonstrated a significant recovery of the paralyzed hindlimb as well as recovery of somatosensory evoked potential and motor evoked potential of injured pathways.Magnetic resonance diffusion tensor imaging data confirmed the intraspinal transplantation of drNPCs did not adversely affect the morphology of the central nervous system or cerebrospinal fluid circulation.Subsequent immunohistochemical analysis showed that drNPCs maintained SOX2 expression characteristic of multipotency in the transplanted spinal cord for at least 12 wk,migrating to areas of axon growth cones.CONCLUSION Our data demonstrated that drNPC transplantation was safe and contributed to improvement of spinal cord function after acute SCI,based on neurological status assessment and neurophysiological recovery within 12 wk after transplantation.The functional improvement described was not associated with neuronal differentiation of the allogeneic drNPCs.Instead,directed drNPCs migration to the areas of active growth cone formation may provide exosome and paracrine trophic support,thereby further supporting the regeneration processes.

人酪氨酸羟化酶基因在猴骨骼肌直接注射后的表达

为了对多途径治疗帕金森病（ＰＤ）提供研究依据，将带人酪氨酸羟化酶基因的质粒ｐＲｃＴＨ与脂质体混合后直接注射至猴骨骼肌内，１００ｄ后取注射部位肌肉组织，以地高辛标记的ｈＴＨＲＮＡ探针进行Ｎｏｒｔｈｅｒｎ杂交，以检测该质粒在非人灵长类活体骨骼肌组织中表达的目的基因的ｍＲＮＡ水平。本研究结果表明，人酪氨酸羟化酶基因在猴体内有较高效率的表达。本研究提示，质粒可作为基因治疗的较理想的表达载体。

非人灵长类胚胎干细胞研究进展

胚胎干细胞是来源于胚胎发育早期的具有多分化潜能的未分化细胞。非人灵长类作为与人类亲缘关系最密切的动物,其ES细胞与人类十分接近。非人灵长类ES细胞的建系成功为开展干细胞的基础和应用研究提供了重要的工具。本文阐述非人灵长类ES细胞的建系、分化的研究进展。

Labeling of cynomolgus monkey bone marrow-derived mesenchymal stem cells for cell tracking by multimodality imaging

Recently,transplantation of allogeneic and autologous cells has been used for regenerative medicine.A critical issue is monitoring migration and homing of transplanted cells,as well as engraftment efficiency and functional capability in vivo.Monitoring of superparamagnetic iron oxide(SPIO) particles by magnetic resonance imaging(MRI) has been used in animal models and clinical settings to track labeled cells.A major limitation of MRI is that the signals do not show biological characteristics of transplanted cells in vivo.Bone marrow mesenchymal stem cells(MSCs) have been extensively investigated for their various therapeutic properties,and exhibit the potential to differentiate into cells of diverse lineages.In this study,cynomolgus monkey MSCs(cMSCs) were labeled with Molday ION Rhodamine-BTM(MIRB),a new SPIO agent,to investigate and characterize the biophysical and MRI properties of labeled cMSCs in vitro and in vivo.The results indicate that MIRB is biocompatible and useful for cMSCs labeling and cell tracking by multimodality imaging.Our method is helpful for detection of transplanted stem cells in vivo,which is required for understanding mechanisms of cell therapy.

Immunity:研究开发出最优的HIV疫苗递送模式

HIV已不再占据头条新闻。这主要是因为抗逆转录病毒药物的成功开发已将HIV病毒感染导致的艾滋病（AIDS）转化为一种慢性的可控制的疾病。然而。当前在全世界大约0．367亿名HIV感染者中，仅约一半的人能够获得控制这种病毒所需的药物。与此同时。新的HIV感染率持续保持在非常高的水平，这突出强调了需要开发一种预防性疫苗。然而，几十年来。