Transplantation of hESCs-Derived Neural Progenitor Cells Alleviates Secondary Damage of Thalamus After Focal Cerebral Infarction in Rats.

Human embryonic stem cells-derived neural progenitor cells (hESCs-NPCs) transplantation holds great potential to treat stroke. We previously reported that delayed secondary degeneration occurs in the ventroposterior nucleus (VPN) of ipsilateral thalamus after distal branch of middle cerebral artery occlusion (dMCAO) in adult male Sprague-Dawley (SD) rats. In this study, we investigate whether hESCs-NPCs would benefit the neural recovery of the secondary damage in the VPN after focal cerebral infarction. Permanent dMCAO was performed with electrocoagulation. Rats were randomized into Sham, dMCAO groups with or without hESCs-NPCs treatment. HESCs-NPCs were engrafted into the peri-infarct regions of rats at 48 h after dMCAO. The transplanted hESCs-NPCs survive and partially differentiate into mature neurons after dMCAO. Notably, hESCs-NPCs transplantation attenuated secondary damage of ipsilateral VPN and improved neurological functions of rats after dMCAO. Moreover, hESCs-NPCs transplantation significantly enhanced the expression of BDNF and TrkB and their interaction in ipsilateral VPN after dMCAO, which was reversed by the knockdown of TrkB. Transplantated hESCs-NPCs reconstituted thalamocortical connection and promoted the formation of synapses in ipsilateral VPN post-dMCAO. These results suggest that hESCs-NPCs transplantation attenuates secondary damage of ipsilateral thalamus after cortical infarction, possibly through activating BDNF/TrkB pathway, enhancing thalamocortical projection, and promoting synaptic formation. It provides a promising therapeutic strategy for secondary degeneration in the ipsilateral thalamus post-dMCAO.

Mesenchymal Stem/Stromal Cells Derived from Human and Animal Perinatal Tissues-Origins, Characteristics, Signaling Pathways, and Clinical Trials.

Mesenchymal stem/stromal cells (MSCs) are currently one of the most extensively researched fields due to their promising opportunity for use in regenerative medicine. There are many sources of MSCs, of which cells of perinatal origin appear to be an invaluable pool. Compared to embryonic stem cells, they are devoid of ethical conflicts because they are derived from tissues surrounding the fetus and can be safely recovered from medical waste after delivery. Additionally, perinatal MSCs exhibit better self-renewal and differentiation properties than those derived from adult tissues. It is important to consider the anatomy of perinatal tissues and the general description of MSCs, including their isolation, differentiation, and characterization of different types of perinatal MSCs from both animals and humans (placenta, umbilical cord, amniotic fluid). Ultimately, signaling pathways are essential to consider regarding the clinical applications of MSCs. It is important to consider the origin of these cells, referring to the anatomical structure of the organs of origin, when describing the general and specific characteristics of the different types of MSCs as well as the pathways involved in differentiation.

Pluripotent Stem Cells for Spinal Cord Injury Repair.

Spinal cord injury (SCI) is a devastating condition of the central nervous system that strongly reduces the patient's quality of life and has large financial costs for the healthcare system. Cell therapy has shown considerable therapeutic potential for SCI treatment in different animal models. Although many different cell types have been investigated with the goal of promoting repair and recovery from injury, stem cells appear to be the most promising. Here, we review the experimental approaches that have been carried out with pluripotent stem cells, a cell type that, due to its inherent plasticity, self-renewal, and differentiation potential, represents an attractive source for the development of new cell therapies for SCI. We will focus on several key observations that illustrate the potential of cell therapy for SCI, and we will attempt to draw some conclusions from the studies performed to date.

In vitro cell culture of amniotic fluid keratinocytes on amniotic membrane: the ideal tissue for repairing skin ulcers.

OBJECTIVE: The amniotic fluid contains a large population of stem keratinocytes demonstrating minimal immunological rejection. Recent evidence suggests that stem cells from the amniotic fluid can be employed in the field of tissue engineering. In this work we identified precursors of the epithelial cells and expanded them in vitro. MATERIALS AND METHODS: After collecting samples of amniotic fluid and separating the cells via centrifugation, we seeded a portion of these cells in selection media to analyze the proliferation of epithelial cells. The stem cells precursors of keratinocytes were identified through specific markers. The expression of these markers was evaluated by immunofluorescence and reverse transcription polymerase chain reaction (PCR). RESULTS: The stem cells demonstrated 90% confluence, after undergoing proliferation in the selection medium for 15 days. Most of these cells tested positive for the keratinocyte-specific markers, but negative for stem cell specific markers. Of note, the identity of the keratinocytes was well established even after several subcultures. CONCLUSIONS: These results suggested that it is feasible to isolate and expand differentiated cell populations in the amniotic fluid from precursor cells. Furthermore, amniotic membranes can be utilized as scaffolds to grow keratinocytes, which can be potentially exploited in areas of skin ulcer transplantation and tissue engineering interventions.

Electroacupuncture Promotes the Survival of the Grafted Human MGE Neural Progenitors in Rats with Cerebral Ischemia by Promoting Angiogenesis and Inhibiting Inflammation.

Stem cells have the potential as a regenerative therapy for cerebral ischemia by improving functional outcomes. However, cell transplantation has some limitations, including a low rate of the grafted cell survival. There is still a major challenge of promoting the harmonious symbiosis between grafted cells and the host. Acupuncture can effectively improve the functional outcome after cerebral ischemia. The present study evaluated the therapeutic effects and explored the mechanism of combined medial ganglionic eminence (MGE) neural progenitors differentiated from human embryonic stem cells (hESCs) with electroacupuncture (EA) in a bilateral common carotid artery occlusion (2VO) rat model. The results showed that EA could promote the survival of the grafted MGE neural progenitors differentiated from hESCs and alleviate learning and memory impairment in rats with cerebral ischemia. This may have partially resulted from inhibited expression of TNF-α and IL-1ß and increased vascular endothelial growth factor (VEGF) expression and blood vessel density in the hippocampus. Our findings indicated that EA could promote the survival of the grafted MGE neural progenitors and enhance transplantation therapy's efficacy by promoting angiogenesis and inhibiting inflammation.

Bone Marrow-Derived VSELs Engraft as Lung Epithelial Progenitor Cells after Bleomycin-Induced Lung Injury.

BACKGROUND: Alveolar type 2 (AT2) cells and bronchioalveolar stem cells (BASC) perform critical regenerative functions in response to lung damage. Published data show that nonhematopoietic, bone marrow-derived "very small embryonic-like stem cells" (VSELs) can differentiate in vivo into surfactant protein C (SPC)-producing AT2 cells in the lung. Here, we test directly whether VSEL-derived BASC and AT2 cells function to produce differentiated progeny. METHODS: using a reporter mouse in which the H2B-GFP fusion protein is driven from the murine SPC promoter, we tested whether bone marrow-derived VSELs or non-VSEL/nonhematopoietic stem cells (non-VSEL/non-HSCs) can differentiate into AT2 and BASC cells that function as progenitor cells. Immediately following bleomycin administration, WT recipient mice underwent intravenous administration of VSELs or non-VSEL/non-HSCs from SPC H2B-GFP mice. GFP+ AT2 and BASC were isolated and tested for progenitor activity using in vitro organoid assays. RESULTS: after 21 days in vivo, we observed differentiation of VSELs but not non-VSEL/non-HSCs into phenotypic AT2 and BASC consistent with previous data in irradiated recipients. Subsequent in vitro organoid assays revealed that VSEL-derived AT2 and BASC maintained physiological potential for differentiation and self-renewal. CONCLUSION: these findings prove that VSELs produce functional BASC and AT2 cells, and this may open new avenues using VSELs to develop effective cell therapy approaches for patients with lung injury.

Lens regeneration: scientific discoveries and clinical possibilities.

In the process of exploring new methods for cataract treatment, lens regeneration is an ideal strategy for effectively restoring accommodative vision and avoiding postoperative complications and has great clinical potential. Lens regeneration, which is not a simple repetition of lens development, depends on the complex regulatory network comprising the FGF, BMP/TGF-ß, Notch, and Wnt signaling pathways. Current research mainly focuses on in situ and in vitro lens regeneration. On the one hand, the possibility of the autologous stem cell in situ regeneration of functional lenses has been confirmed; on the other hand, both embryonic stem cells and induced pluripotent stem cells have been induced into lentoid bodies in vitro which are similar to the natural lens to a certain extent. This article will briefly summarize the regulatory mechanisms of lens development, describe the recent progress of lens regeneration, explore the key molecular signaling pathways, and, more importantly, discuss the prospects and challenges of their clinical applications to provide reference for clinical transformations.

Method for selective ablation of undifferentiated human pluripotent stem cell populations for cell-based therapies.

Human pluripotent stem cells (PSCs), which are composed of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), provide an opportunity to advance cardiac cell therapy-based clinical trials. However, an important hurdle that must be overcome is the risk of teratoma formation after cell transplantation due to the proliferative capacity of residual undifferentiated PSCs in differentiation batches. To tackle this problem, we propose the use of a minimal noncardiotoxic doxorubicin dose as a purifying agent to selectively target rapidly proliferating stem cells for cell death, which will provide a purer population of terminally differentiated cardiomyocytes before cell transplantation. In this study, we determined an appropriate in vitro doxorubicin dose that (a) eliminates residual undifferentiated stem cells before cell injection to prevent teratoma formation after cell transplantation and (b) does not cause cardiotoxicity in ESC-derived cardiomyocytes (CMs) as demonstrated through contractility analysis, electrophysiology, topoisomerase activity assay, and quantification of reactive oxygen species generation. This study establishes a potentially novel method for tumorigenic-free cell therapy studies aimed at clinical applications of cardiac cell transplantation.

The Role of B Cells in PE Pathophysiology: A Potential Target for Perinatal Cell-Based Therapy?

The pathophysiology of preeclampsia (PE) is poorly understood; however, there is a large body of evidence that suggests a role of immune cells in the development of PE. Amongst these, B cells are a dominant element in the pathogenesis of PE, and they have been shown to play an important role in various immune-mediated diseases, both as pro-inflammatory and regulatory cells. Perinatal cells are defined as cells from birth-associated tissues isolated from term placentas and fetal annexes and more specifically from the amniotic membrane, chorionic membrane, chorionic villi, umbilical cord (including Wharton's jelly), the basal plate, and the amniotic fluid. They have drawn particular attention in recent years due to their ability to modulate several aspects of immunity, making them promising candidates for the prevention and treatment of various immune-mediated diseases. In this review we describe main findings regarding the multifaceted in vitro and in vivo immunomodulatory properties of perinatal cells, with a focus on B lymphocytes. Indeed, we discuss evidence on the ability of perinatal cells to inhibit B cell proliferation, impair B cell differentiation, and promote regulatory B cell formation. Therefore, the findings discussed herein unveil the possibility to modulate B cell activation and function by exploiting perinatal immunomodulatory properties, thus possibly representing a novel therapeutic strategy in PE.

Cellular therapy for treatment of spinal cord injury in Zebrafish model.

Spinal cord injury is a serious problem with a high rate of morbidity and mortality for all persons, especially young people (15-25 years old). Due to the large burden and the costs incurred on the government, finding the best therapeutic approach is necessary. In this respect, treatment strategies based on the disease mechanism can be effective. After the first trauma of spinal cord cascades, cellular events happen one after the other known as secondary trauma. The mechanism of secondary events of spinal cord injury could be helpful for target therapy as trying to stop the secondary trauma. Herein, some medical and surgical therapy has been introduced and cell therapy strategy was considered as a recent method. Actually, cell therapy is defined as the application of different cells including mesenchymal stem cells, embryonic stem cells, induced pluripotent stem cells, and some others to replace or reconstruct the damaged tissues and restore their functions. However, as a newly emerged therapeutic method, cell therapy should be used through various subclinical studies in animal models to assess the efficacy of the treatment under controlled conditions. In this review, the role of Zebrafish as a recommended model has been discussed and combinatory approach as the probably most useful treatment has been suggested.

Transplantation of Human Neural Precursor Cells Reverses Syrinx Growth in a Rat Model of Post-Traumatic Syringomyelia.

Posttraumatic syringomyelia (PTS) is a serious condition of progressive expansion of spinal cord cysts, affecting patients with spinal cord injury years after injury. To evaluate neural cell therapy to prevent cyst expansion and potentially replace lost neurons, we developed a rat model of PTS. We combined contusive trauma with subarachnoid injections of blood, causing tethering of the spinal cord to the surrounding vertebrae, resulting in chronically expanding cysts. The cysts were usually located rostral to the injury, extracanalicular, lined by astrocytes. T2*-weighted magnetic resonance imaging (MRI) showed hyperintense fluid-filled cysts but also hypointense signals from debris and iron-laden macrophages/microglia. Two types of human neural stem/progenitor cells-fetal neural precursor cells (hNPCs) and neuroepithelial-like stem cells (hNESCs) derived from induced pluripotent stem cells-were transplanted to PTS cysts. Cells transplanted into cysts 10 weeks after injury survived at least 10 weeks, migrated into the surrounding parenchyma, but did not differentiate during this period. The cysts were partially obliterated by the cells, and cyst walls often merged with thin layers of cells in between. Cyst volume measurements with MRI showed that the volumes continued to expand in sham-transplanted rats by 102%, while the cyst expansion was effectively prevented by hNPCs and hNESCs transplantation, reducing the cyst volumes by 18.8% and 46.8%, respectively. The volume reductions far exceeded the volume of the added human cells. Thus, in an animal model closely mimicking the clinical situation, we provide proof-of-principle that transplantation of human neural stem/progenitor cells can be used as treatment for PTS.

Long-term safety and tolerability of subretinal transplantation of embryonic stem cell-derived retinal pigment epithelium in Asian Stargardt disease patients.

BACKGROUND: Although human embryonic stem cells (hESCs) have been considered a potential therapeutic option for regenerative medicine, there are some concerns regarding tumorigenicity, immunogenicity and ethical considerations. Stargardt macular dystrophy (SMD) is the most common form of juvenile macular degeneration that causes early onset blindness. Therapeutic options for SMD remain limited, although several treatment strategies are currently under investigation. Here, we report a 3-year assessment of a phase I clinical trial involving subretinal transplantation of hESC-retinal pigment epithelium (RPE) cells in patients with SMD. METHODS: This prospective, non-randomised clinical trial included three patients with SMD. All transplant recipients had central visual acuity no better than 20/400. Trans-pars plana vitrectomy was performed in the eye with poorer vision. RPE cells were reconstituted in balanced salt solution plus, then injected into the subretinal space using a semi-automated subretinal injection method. RESULTS: No serious adverse events occurred throughout the 3-year period following the injection of hESC-RPE cells. The functional and anatomical results were favourable, compared with the natural course of SMD reported in the ProgStar study. One patient showed best-corrected visual acuity improvement, while the other patients had stable best-corrected visual acuity during the 3-year follow-up period. CONCLUSION: These results suggest the long-term safety, tolerability, and feasibility of subretinal hESC-derived RPE cell transplantation in regenerative medicine. TRIAL REGISTRATION NUMBER: NCT01625559.

Stem cell therapy in patients with epilepsy: A systematic review.

PURPOSE: The existing evidence of the potential applications and benefits of stem cell transplantation (SCT) in people with epilepsy and also its adverse effects in humans were systematically reviewed. METHODS: MEDLINE (accessed from PubMed), Google Scholar, and Scopus from inception to August 17, 2020 were systematically reviewed for related published manuscripts. The following key words (in the title) were used: "stem cell" AND "epilepsy" OR "seizure". Articles written in English that were human studies on stem cell transplantation in people with epilepsy were all included. RESULTS: We could identify six related articles. Because of their different methodologies, performing a meta-analysis was not feasible; they included 38 adults and 81 pediatric patients together. Five studies were single-arm human studies; there were no serious adverse events in any of the studies. CONCLUSION: While stem cell transplantation seems like a promising therapeutic option for patients with drug-resistant epilepsy, data on its application is scarce and of low quality. For now, clinical stem cell-based interventions are not justified. Perhaps, in the future, there will be a rigorous and intensely scrutinized clinical trial protocol with informed consent that could provide enough scientific merit and could meet the required ethical standards.

Administration of Amyloid Precursor Protein Gene Deleted Mouse ESC-Derived Thymic Epithelial Progenitors Attenuates Alzheimer's Pathology.

Alzheimer's disease (AD) is a devastating neurodegenerative disorder and the most common cause of dementia in older adults. Although amyloid-beta (Aß) plaque deposition and chronic neuroinflammation in the central nervous system (CNS) contribute to AD pathology, neither Aß plaque removal nor anti-inflammatory therapy has shown much clinical success, suggesting that the combinational therapies for the disease-causative factors may be needed for amelioration. Recent data also suggest that systemic immunity in AD should be boosted, rather than suppressed, to drive an immune-dependent cascade needed for Aß clearance and brain repair. Thymic epithelial cells (TECs) not only play a critical role in supporting T cell development but also mediate the deletion of autoreactive T cells by expressing autoantigens. We have reported that embryonic stem cells (ESCs) can be selectively induced to differentiate into thymic epithelial progenitors (TEPs) in vitro that further develop into TECs in vivo to support T cell development. We show here that transplantation of mouse ESC (mESC)-TEPs into AD mice reduced cerebral Aß plaque load and improved cognitive performance, in correlation with an increased number of T cells, enhanced choroid plexus (CP) gateway activity, and increased number of macrophages in the brain. Furthermore, transplantation of the amyloid precursor protein (APP) gene deleted mESC-TEPs (APP-/-) results in more effective reduction of AD pathology as compared to wild-type (APP+/+) mESC-TEPs. This is associated with the generation of Aß-specific T cells, which leads to an increase of anti-Aß antibody (Ab)-producing B cells in the spleen and enhanced levels of anti-Aß antibodies in the serum, as well as an increase of Aß phagocytosing macrophages in the CNS. Our results suggest that transplantation of APP-/- human ESC- or induced pluripotent stem cell (iPSC)-derived TEPs may provide a new tool to mitigate AD in patients.

Utility of Common Marmoset (Callithrix jacchus) Embryonic Stem Cells in Liver Disease Modeling, Tissue Engineering and Drug Metabolism.

The incidence of liver disease is increasing significantly worldwide and, as a result, there is a pressing need to develop new technologies and applications for end-stage liver diseases. For many of them, orthotopic liver transplantation is the only viable therapeutic option. Stem cells that are capable of differentiating into all liver cell types and could closely mimic human liver disease are extremely valuable for disease modeling, tissue regeneration and repair, and for drug metabolism studies to develop novel therapeutic treatments. Despite the extensive research efforts, positive results from rodent models have not translated meaningfully into realistic preclinical models and therapies. The common marmoset Callithrix jacchus has emerged as a viable non-human primate model to study various human diseases because of its distinct features and close physiologic, genetic and metabolic similarities to humans. C. jacchus embryonic stem cells (cjESC) and recently generated cjESC-derived hepatocyte-like cells (cjESC-HLCs) could fill the gaps in disease modeling, liver regeneration and metabolic studies. They are extremely useful for cell therapy to regenerate and repair damaged liver tissues in vivo as they could efficiently engraft into the liver parenchyma. For in vitro studies, they would be advantageous for drug design and metabolism in developing novel drugs and cell-based therapies. Specifically, they express both phase I and II metabolic enzymes that share similar substrate specificities, inhibition and induction characteristics, and drug metabolism as their human counterparts. In addition, cjESCs and cjESC-HLCs are advantageous for investigations on emerging research areas, including blastocyst complementation to generate entire livers, and bioengineering of discarded livers to regenerate whole livers for transplantation.

Generation of rat blood vasculature and hematopoietic cells in rat-mouse chimeras by blastocyst complementation.

Interspecies chimera through blastocyst complementation could be an alternative approach to create human organs in animals by using human pluripotent stem cells. A mismatch of the major histocompatibility complex of vascular endothelial cells between the human and host animal will cause graft rejection in the transplanted organs. Therefore, to achieve a transplantable organ in animals without rejection, creation of vascular endothelial cells derived from humans within the organ is necessary. In this study, to explore whether donor xeno-pluripotent stem cells can compensate for blood vasculature in host animals, we generated rat-mouse chimeras by injection of rat embryonic stem cells (rESCs) into mouse blastocysts with deficiency of Flk-1 protein, which is associated with endothelial and hematopoietic cell development. We found that rESCs could differentiate into vascular endothelial and hematopoietic cells in the rat-mouse chimeras. The whole yolk sac (YS) of Flk-1EGFP/EGFP rat-mouse chimera was full of rat blood vasculature. Rat genes related to vascular endothelial cells, arteries, and veins, blood vessels formation process, as well as hematopoietic cells, were highly expressed in the YS. Our results suggested that rat vascular endothelial cells could undergo proliferation, migration, and self-assembly to form blood vasculature and that hematopoietic cells could differentiate into B cells, T cells, and myeloid cells in rat-mouse chimeras, which was able to rescue early embryonic lethality caused by Flk-1 deficiency in mouse.

Transplanted Embryonic Neurons Improve Functional Recovery by Increasing Activity in Injured Cortical Circuits.

Transplantation of appropriate neuronal precursors after injury is a promising strategy to reconstruct cortical circuits, but the efficiency of these approaches remains limited. Here, we applied targeted apoptosis to selectively ablate layer II/III pyramidal neurons in the rat juvenile cerebral cortex and attempted to replace lost neurons with their appropriate embryonic precursors by transplantation. We demonstrate that grafted precursors do not migrate to replace lost neurons but form vascularized clusters establishing reciprocal synaptic contacts with host networks and show functional integration. These heterotopic neuronal clusters significantly enhance the activity of the host circuits without causing epileptic seizures and attenuate the apoptotic injury-induced functional deficits in electrophysiological and behavioral tests. Chemogenetic activation of grafted neurons further improved functional recovery, and the persistence of the graft was necessary for maintaining restored functions in adult animals. Thus, implanting neuronal precursors capable to form synaptically integrated neuronal clusters combined with activation-based approaches represents a useful strategy for helping long-term functional recovery following brain injury.

TWIST1-Reprogrammed Endothelial Cell Transplantation Potentiates Neovascularization-Mediated Diabetic Wound Tissue Regeneration.

Hypovascularized diabetic nonhealing wounds are due to reduced number and impaired physiology of endogenous endothelial progenitor cell (EPC) population that limits their recruitment and mobilization at the wound site. For enrichment of the EPC repertoire from nonendothelial precursors, abundantly available mesenchymal stromal cells (MSC) were reprogrammed into induced endothelial cells (iEC). We identified cell signaling molecular targets by meta-analysis of microarray data sets. BMP-2 induction leads to the expression of inhibitory Smad 6/7-dependent negative transcriptional regulation of ID1, rendering the latter's reduced binding to TWIST1 during transdifferentiation of Wharton jelly-derived MSC (WJ-MSC) into iEC. TWIST1, in turn, regulates endothelial gene transcription, positively of proangiogenic KDR and negatively, in part, of antiangiogenic SFRP4 Twist1 reprogramming enhanced the endothelial lineage commitment of WJ-MSC and increased the vasculogenic potential of reprogrammed endothelial cells (rEC). Transplantation of stable TWIST1 rEC into a type 1 and 2 diabetic full-thickness splinted wound healing murine model enhanced the microcirculatory blood flow and accelerated the wound tissue regeneration. An increased or decreased colocalization of GFP with KDR/SFRP4 and CD31 in the regenerated diabetic wound bed with TWIST1 overexpression or silencing (piLenti-TWIST1-shRNA-GFP), respectively, further confirmed improved neovascularization. This study depicted the reprogramming of WJ-MSC into rEC using unique transcription factor TWIST1 for an efficacious cell transplantation therapy to induce neovascularization-mediated diabetic wound tissue regeneration.

Cerebral organoids transplantation improves neurological motor function in rat brain injury.

BACKGROUND AND PURPOSE: Cerebral organoids (COs) have been used for studying brain development, neural disorders, and species-specific drug pharmacology and toxicology, but the potential of COs transplantation therapy for brain injury remains to be answered. METHODS: With preparation of traumatic brain injury (TBI) model of motor dysfunction, COs at 55 and 85 days (55 and 85 d-CO) were transplanted into damaged motor cortex separately to identify better transplantation donor for brain injury. Further, the feasibility, effectiveness, and underlying mechanism of COs transplantation therapy for brain injury were explored. RESULTS: 55 d-CO was demonstrated as better transplantation donor than 85 d-CO, evidenced by more neurogenesis and higher cell survival rate without aggravating apoptosis and inflammation after transplantation into damaged motor cortex. Cells from transplanted COs had the potential of multilinage differentiation to mimic in-vivo brain cortical development, support region-specific reconstruction of damaged motor cortex, form neurotransmitter-related neurons, and migrate into different brain regions along corpus callosum. Moreover, COs transplantation upregulated hippocampal neural connection proteins and neurotrophic factors. Notably, COs transplantation improved neurological motor function and reduced brain damage. CONCLUSIONS: This study revealed 55 d-CO as better transplantation donor and demonstrated the feasibility and efficacy of COs transplantation in TBI, hoping to provide first-hand preclinical evidence of COs transplantation for brain injury.

Grafting Embryonic Raphe Neurons Reestablishes Serotonergic Regulation of Sympathetic Activity to Improve Cardiovascular Function after Spinal Cord Injury.

Cardiovascular dysfunction often occurs after high-level spinal cord injury. Disrupting supraspinal vasomotor pathways affects basal hemodynamics and contributes to the development of autonomic dysreflexia (AD). Transplantation of early-stage neurons to the injured cord may reconstruct the descending projections to enhance cardiovascular performance. To determine the specific role of reestablishing serotonergic regulation of hemodynamics, we implanted serotonergic (5-HT+) neuron-enriched embryonic raphe nucleus-derived neural stem cells/progenitors (RN-NSCs) into a complete spinal cord transection lesion site in adult female rats. Grafting embryonic spinal cord-derived NSCs or injury alone served as 2 controls. Ten weeks after injury/grafting, histological analysis revealed well-survived grafts and partial integration with host tissues in the lesion site. Numerous graft-derived serotonergic axons topographically projected to the caudal autonomic regions. Neuronal tracing showed that host supraspinal vasomotor pathways regenerated into the graft, and 5-HT+ neurons within graft and host brainstem neurons were transsynaptically labeled by injecting pseudorabies virus (PRV-614) into the kidney, indicating reconnected serotonergic circuits regulating autonomic activity. Using an implanted telemeter to record cardiovascular parameters, grafting RN-NSCs restored resting mean arterial pressure to normal levels and remarkably alleviated naturally occurring and colorectal distension-induced AD. Subsequent pharmacological blockade of 5-HT2A receptors with ketanserin in RN-NSC-grafted rats reduced resting mean arterial pressure and increased heart rate in all but 2 controls. Furthermore, spinal cord retransection below RN-NSC grafts partially eliminated the recovery in AD. Collectively, these data indicate that RN-NSCs grafted into a spinal cord injury site relay supraspinal control of serotonergic regulation for sympathetic activity to improve cardiovascular function.SIGNIFICANCE STATEMENT Disruption of supraspinal vasomotor pathways results in cardiovascular dysfunction following high-level spinal cord injury. To reestablish the descending regulation of autonomic function, we transplanted serotonergic neuron enriched embryonic raphe nucleus-derived neural stem cells/progenitors into the lesion site of completely transected rat spinal cord. Consequently, grafted raphe nucleus-derived neural stem cells/progenitors acted as a neuronal relay to reconnect supraspinal center and spinal sympathetic neurons below the injury. The reconstituted serotonergic regulation of sympathetic activity led to the improvement of hemodynamic parameters and mitigated autonomic dysreflexia. Based on morphological and physiological results, this study validates the effectiveness of transplanting early-stage serotonergic neurons into the spinal cord for cardiovascular functional recovery after spinal cord injury.