Reduction of neural and vascular damage by transplantation of VEGF-secreting neural stem cells after cerebral ischemia

Reconstituting neurovascular unit based on the close relations between neural stem cells and endothelial cells: an effective method to explore neurogenesis and angiogenesis

The discovery of neural stem cells (NSCs) and their microenvironment, the NSC niche, brought new therapeutic strategies through neurogenesis and angiogenesis for stroke and most neurodegenerative diseases, including Alzheimer's disease. Based on the close links between NSCs and endothelial cells, the integration of neurogenesis and angiogenesis of the NSC niche is also a promising area to the neurovascular unit (NVU) modeling and is now offering a powerful tool to advance our understanding of the brain. In this review, critical aspects of the NVU and model systems are discussed. First, we briefly describe the interaction of each part in the NSC niche. Second, we introduce the co-culture system, microfluidic platforms, and stem cell-derived 3D reconstitution used in NVU modeling based on the close relations between NSCs and endothelial cells, and various characteristics of cell interactions in these systems are also described. Finally, we address the challenges in modeling the NVU that can potentially be overcome by employing strategies for advanced biomaterials and stem cell co-culture use. Based on these approaches, researchers will continue to develop predictable technologies to control the fate of stem cells, achieve accurate screening of drugs for the nervous system, and advance the clinical application of NVU models.

Neural Stem Cell-Laden Self-Healing Polysaccharide Hydrogel Transplantation Promotes Neurogenesis and Functional Recovery after Cerebral Ischemia in Rats

Exploring a strategy to effectively repair cerebral ischemic injury is a critical requirement for neuroregeneration. Herein, we transplanted a neural stem cell (NSC)-laden self-healing and injectable hydrogel into the brains of ischemic rats and evaluated its therapeutic effects. We observed an improvement in neurological functions in rats transplanted with the NSC-laden hydrogel. This strategy is sufficiently efficient to support neuroregeneration evidenced by NSC proliferation, differentiation, and athletic movement recovery of rats. This therapeutic effect relates to the inhibition of the astrocyte reaction and the increased expression of vascular endothelial growth factor. This work provides a novel approach to repair cerebral ischemic injury.

Apigenin as a Candidate Prenatal Treatment for Trisomy 21: Effects in Human Amniocytes and the Ts1Cje Mouse Model

Human fetuses with trisomy 21 (T21) have atypical brain development that is apparent sonographically in the second trimester. We hypothesize that by analyzing and integrating dysregulated gene expression and pathways common to humans with Down syndrome (DS) and mouse models we can discover novel targets for prenatal therapy. Here, we tested the safety and efficacy of apigenin, identified with this approach, in both human amniocytes from fetuses with T21 and in the Ts1Cje mouse model. In vitro, T21 cells cultured with apigenin had significantly reduced oxidative stress and improved antioxidant defense response. In vivo, apigenin treatment mixed with chow was administered prenatally to the dams and fed to the pups over their lifetimes. There was no significant increase in birth defects or pup deaths resulting from prenatal apigenin treatment. Apigenin significantly improved several developmental milestones and spatial olfactory memory in Ts1Cje neonates. In addition, we noted sex-specific effects on exploratory behavior and long-term hippocampal memory in adult mice, and males showed significantly more improvement than females. We demonstrated that the therapeutic effects of apigenin are pleiotropic, resulting in decreased oxidative stress, activation of pro-proliferative and pro-neurogenic genes (KI67, Nestin, Sox2, and PAX6), reduction of the pro-inflammatory cytokines INFG, IL1A, and IL12P70 through the inhibition of NFκB signaling, increase of the anti-inflammatory cytokines IL10 and IL12P40, and increased expression of the angiogenic and neurotrophic factors VEGFA and IL7. These studies provide proof of principle that apigenin has multiple therapeutic targets in preclinical models of DS.

Transplantation of vascular endothelial growth factor-modified neural stem/progenitor cells promotes the recovery of neurological function following hypoxic-ischemic brain damage

Neural stem/progenitor cell (NSC) transplantation has been shown to effectively improve neurological function in rats with hypoxic-ischemic brain damage. Vascular endothelial growth factor (VEGF) is a signaling protein that stimulates angiogenesis and improves neural regeneration. We hypothesized that transplantation of VEGF-transfected NSCs would alleviate hypoxic-ischemic brain damage in neonatal rats. We produced and transfected a recombinant lentiviral vector containing the VEGF₁₆₅ gene into cultured NSCs. The transfected NSCs were transplanted into the left sensorimotor cortex of rats 3 days after hypoxic-ischemic brain damage. Compared with the NSCs group, VEGF mRNA and protein expression levels were increased in the transgene NSCs group, and learning and memory abilities were significantly improved at 30 days. Furthermore, histopathological changes were alleviated in these animals. Our findings indicate that transplantation of VEGF-transfected NSCs may facilitate the recovery of neurological function, and that its therapeutic effectiveness is better than that of unmodified NSCs.

Neuroprotective therapies in glaucoma: II. Genetic nanotechnology tools

Neurotrophic factor genome engineering could have many potential applications not only in the deeper understanding of neurodegenerative disorders but also in improved therapeutics. The fields of nanomedicine, regenerative medicine, and gene/cell-based therapy have been revolutionized by the development of safer and efficient non-viral technologies for gene delivery and genome editing with modern techniques for insertion of the neurotrophic factors into clinically relevant cells for a more sustained pharmaceutical effect. It has been suggested that the long-term expression of neurotrophic factors is the ultimate approach to prevent and/or treat neurodegenerative disorders such as glaucoma in patients who do not respond to available treatments or are at the progressive stage of the disease. Recent preclinical research suggests that novel neuroprotective gene and cell therapeutics could be promising approaches for both non-invasive neuroprotection and regenerative functions in the eye. Several progenitor and retinal cell types have been investigated as potential candidates for glaucoma neurotrophin therapy either as targets for gene therapy, options for cell replacement therapy, or as vehicles for gene delivery. Therefore, in parallel with deeper understanding of the specific protective effects of different neurotrophic factors and the potential therapeutic cell candidates for glaucoma neuroprotection, the development of non-invasive and highly specific gene delivery methods with safe and effective technologies to modify cell candidates for life-long neuroprotection in the eye is essential before investing in this field.

Classic Studies on the Potential of Stem Cell Neuroregeneration

The 1990s and 2000s were the beginning of an exciting time period for developmental neuroscience and neural stem cell research. By better understanding brain plasticity and the birth of new neurons in the adult brain, contrary to established dogma, hope for therapy from devastating neurological diseases was generated. The potential for stem cells to provide functional recovery in humans remains to be further tested and to further move into the clinical trial realm. The future certainly has great promise on stem cells to assist in alleviation of difficult-to-treat neurologic disorders. This article reviews classic studies of the 1990s and 2000s that paved the way for the advances of today, which can in turn lead to tomorrow's therapies.

Adult stem cells in neural repair: Current options, limitations and perspectives

Stem cells represent a promising step for the future of regenerative medicine. As they are able to differentiate into any cell type, tissue or organ, these cells are great candidates for treatments against the worst diseases that defy doctors and researchers around the world. Stem cells can be divided into three main groups: (1) embryonic stem cells; (2) fetal stem cells; and (3) adult stem cells. In terms of their capacity for proliferation, stem cells are also classified as totipotent, pluripotent or multipotent. Adult stem cells, also known as somatic cells, are found in various regions of the adult organism, such as bone marrow, skin, eyes, viscera and brain. They can differentiate into unipotent cells of the residing tissue, generally for the purpose of repair. These cells represent an excellent choice in regenerative medicine, every patient can be a donor of adult stem cells to provide a more customized and efficient therapy against various diseases, in other words, they allow the opportunity of autologous transplantation. But in order to start clinical trials and achieve great results, we need to understand how these cells interact with the host tissue, how they can manipulate or be manipulated by the microenvironment where they will be transplanted and for how long they can maintain their multipotent state to provide a full regeneration.

Monitoring ferumoxide-labelled neural progenitor cells and lesion evolution by magnetic resonance imaging in a model of cell transplantation in cerebral ischaemia

Efficacy of neural stem/progenitor cell (NPC) therapies after cerebral ischaemia could be better evaluated by monitoring in vivo migration and distribution of cells post-engraftment in parallel with analysis of lesion volume and functional recovery. Magnetic resonance imaging (MRI) is ideally placed to achieve this, but still poses several challenges. We show that combining the ferumoxide MRI contrast agent Endorem with protamine sulphate (FePro) improves iron oxide uptake in cells compared to Endorem alone and is non-toxic. Hence FePro complex is a better contrast agent than Endorem for monitoring NPCs. FePro complex-labelled NPCs proliferated and differentiated normally in vitro, and upon grafting into the brain 48 hours post-ischaemia they were detected in vivo by MRI. Imaging over four weeks showed the development of a confounding endogenous hypointense contrast evolution at later timepoints within the lesioned tissue. This was at least partly due to accumulation within the lesion of macrophages and endogenous iron. Neither significant NPC migration, assessed by MRI and histologically, nor a reduction in the ischaemic lesion volume was observed in NPC-grafted brains.  Crucially, while MRI provides reliable information on engrafted cell location early after an ischaemic insult, pathophysiological changes to ischaemic lesions can interfere with cellular imaging at later timepoints.

Neuroprotection of VEGF-expression neural stem cells in neonatal cerebral palsy rats

Cerebral palsy (CP) is a very common neural system development disorder that can cause physical disability in human. Here, we studied the neuroprotective effect of vascular endothelial growth factor (VEGF)-transfected neural stem cells (NSCs) in newborn rats with cerebral palsy (CP). Seven-day-old Sprague-Dawley rats were randomly divided into four groups: sham operation (control group), PBS transplantation (PBS group), VEGF+NSCs transplantation (transgene NSCs group) and NSCs transplantation groups (NSCs group). PBS, Transgene NSCs and NSCs groups respectively received stereotactic injections of PBS, lentiviral vector (pGC-FU-VEGF) infected NSCs or a NSCs suspension in the left sensory-motor cortex 3 days after CP model was established. The NSCs activity, their impacts on neural cell growth and apoptosis, brain development and animal behaviors were examined on the animals up to age 35-days. As expected, unilateral carotid artery occlusion plus hypoxia (cerebral palsy model) resulted in severe neural developmental disorders, including slowed growth, increased in cortical neuron apoptosis, decreased cerebral cortex micro-vessel density and retarded behavior developments. Transplantation of NSCs not only resulted in increases in VEGF protein expression in rat brains, but also largely prevented the behavioral defects and brain tissue pathology that resulted from cerebral palsy procedure, with animals received VEGF transfected NSCs always being marginally better than these received un-transfected cells. In conclusion, NSCs transplantation can partially prevent/slow down the brain damages that are associated with CP in the newborn rats, suggesting a new possible strategy for CP treatment.

Huashan Hospital affiliated to Fudan University: spanning a century of history

Established in 1907, Huashan Hospital affiliated to Fudan University represents in microcosm the growth of modern Chinese medical science and shows its course of development. Over the past 103 years, the hospital has grown from a staff of a dozen to 3103 staff members, covering an area of 37,396 m(2) with 1216 hospital beds. Huashan Hospital has grown into one of the best-known hospitals in China with multiple world-renowned disciplines, including neurosurgery, hand surgery, dermatology, and infectious disease.

The effects of human umbilical cord blood transplantation in rats with experimentally induced spinal cord injury

OBJECT

Even though there have been many efforts to recover neuronal dysfunction following spinal cord injuries, there are limitations to the treatment of these injuries. The purpose of this laboratory investigation was to determine the clinical and neurophysiological effects of human umbilical cord blood (HUCB) transplantation in a rat hemisection model of spinal cord injury.

METHODS

In this study, experimental hemisection of the thoracic spinal cord was performed in rats. The rats were divided into 4 groups (6 rats in each group). One group of rats (Group 1) underwent thoracic laminectomy only. Rats in Group 2 underwent laminectomy and right hemisection of the thoracic spinal cord. Rats in Group 3 underwent right hemisection and implantation of freshly obtained HUCB on Day 0 postinjury. Rats in Group 4 underwent hemisection and implantation of freshly obtained HUCB on Day 4 postinjury. Clinical evaluations of rat motor function included the following: neurological examination, Rotarod performance, and inclined plane tests. Rats also underwent reflex evaluation.

RESULTS

The neurological examinations revealed that the frequency of plegic rats was 70.8% at the beginning of the study across all 4 groups; this value decreased to 20.8% by the end of the study. The percentage of rats with a normal examination increased from 25% to 50%. The results of Rotarod performance and 8-week inclined plane performance tests showed statistical significance (p < 0.05) in an overall group comparison across all time points. At the end of the 8 weeks, a statistically significant difference was found in the inclined plane test results between rats in Groups 1 and 2. There were no statistically significant differences between Groups 1, 3, and 4 (p < 0.05). When the reflex responses of the hemisectioned sides were compared, statistically significant differences were detected between groups (p < 0.05). All groups were significantly different with regard to the right-side reflex response score (p < 0.05). Spinal cord preparations of rats in all groups were examined for histopathological changes.

CONCLUSIONS

Human umbilical cord blood is stem cell rich and easily available, and it carries less risk of inducing a graft-versus-host reaction in the recipient. Human umbilical cord blood serum is also noted to contain stem cell–promoting factors, which is why cell isolation was not used in this study. Freshly obtained cord blood was also used because storage of cord blood has been reported to have some negative effects on stem cells. Transplantation of freshly obtained HUCB into the hemisectioned spinal cord experimental model demonstrated clinical and neurophysiological improvement.

The targeting expression of the vascular endothelial growth factor gene in endothelial cells regulated by HRE.ppET-1

The success of gene therapy depends largely on the efficacy of gene delivery vector systems that can deliver genes to target organs or cells selectively and efficiently with minimal toxicity. Here, we show that by using the HRE.ppET-1 regulatory element, we were able to restrict expression of the transgene of vascular endothelial growth factor (VEGF) to endothelial cells exclusively in hypoxic conditions. Eukaryotic expression vectors such as pEGFP-HRE.ppET-1, pcDNA3.1-VEGF+Pa, pcDNA3.1-ppET-1+ EGF+Pa, and pcDNA3.1-HRE.ppET-1+VEGF+Pa were constructed by using a series of nuclear molecule handling methods like PCR, enzyme digestion. The recombinant vectors were transfected into HUVEC cells and HL7702 cells by the lipofectin method. GFP expression was observed with a fluorescence microscope to validate the specificity of expression in endothelial cells under the regulation of HRE.ppET-1 element. Cobalt chloride (final concentration 100 mumol/L) was added to the medium to mimic hypoxia in vitro. After transfection of vectors, the expression of VEGF mRNA was detected by RT-PCR, and the expression of VEGF was detected by Western blotting and ELISA methods under normoxia and hypoxia, respectively. The cell proliferation rate was detected by the MTT test. The expression of GFP revealed that the exterior gene was transcripted effectively in endothelial cells regulated by the HRE.ppET-1 element, while the expression of GFP was very weak in nonendothelial cells. The results of RT-PCR, Western blotting and ELISA showed that VEGF gene expression in the pcDNA3.1-HRE.ppET-1+VEGF+Pa group and in the pcDNA3.1-ppET-1+VEGF+Pa group was higher in hypoxia than it was in normoxia (P<0.05). The MTT test showed that the proliferation rate of HUVEC transfected with HPVA under hypoxia exceeded that of the control group. We conclude that the HRE.ppET-1 element was expressed specifically in endothelial cells, and can increase the expression of VEGF in hypoxia and stimulate proliferation of endothelial cells. Taking advantage of these facts could greatly improve the efficiency of gene therapy. The vector would be valuable for various gene transfer studies targeting endothelial cells.

The Department of Neurosurgery at Shanghai Huashan Hospital

The Department of Neurosurgery at Shanghai HuaShan Hospital is one of the oldest neurosurgical departments in China and is also one of the country's leading academic neurosurgery programs. The department was established in 1953 under the direction of Yuquan Shi, one of the pioneers and founders of neurosurgery in China, and is currently directed by Liang-Fu Zhou. The HuaShan Neurosurgical Group Hospital and the Shanghai HuaShan Institution of Neurosurgery were established in 2000. The department currently has 67 faculty and 450 beds distributed among one main hospital (HuaShan Hospital) and seven affiliates. More than 8000 neurosurgical procedures are performed annually. The Shanghai Emergency Center of Neurosurgery is also maintained by the department. The Department of Neurosurgery at HuaShan Hospital will continue to grow in strength and position as one of the leaders in the field of neurosurgery.

Experimental concepts for toxicity prevention and tissue restoration after central nervous system irradiation

Several experimental strategies of radiation-induced central nervous system toxicity prevention have recently resulted in encouraging data. The present review summarizes the background for this research and the treatment results. It extends to the perspectives of tissue regeneration strategies, based for example on stem and progenitor cells. Preliminary data suggest a scenario with individually tailored strategies where patients with certain types of comorbidity, resulting in impaired regeneration reserve capacity, might be considered for toxicity prevention, while others might be "salvaged" by delayed interventions that circumvent the problem of normal tissue specificity. Given the complexity of radiation-induced changes, single target interventions might not suffice. Future interventions might vary with patient age, elapsed time from radiotherapy and toxicity type. Potential components include several drugs that interact with neurodegeneration, cell transplantation (into the CNS itself, the blood stream, or both) and creation of reparative signals and a permissive microenvironment, e.g., for cell homing. Without manipulation of the stem cell niche either by cell transfection or addition of appropriate chemokines and growth factors and by providing normal perfusion of the affected region, durable success of such cell-based approaches is hard to imagine.

Platelet-derived growth factor-mediated gliomagenesis and brain tumor recruitment

Platelet-derived growth factor (PDGF) is a growth factor family of ligands and receptors known to activate phosphatidylinositol 3-kinase, mitogen-activated protein kinase, Jak family kinase, Src family kinase, and phospholipase Cgamma signal transduction pathways, some of which have been causally linked to glioma formation. Extensive involvement of PDGF in development and its implication in a variety of pathologic conditions, including gliomagenesis, are mediated not only by autocrine effects but by paracrine effects. Many researchers view brain tumors as clonal entities derived from the cancer stem cell; however, recent documentation of the importance of the tumor microenvironment for glioma initiation and progression as well as the ability of neural stem or progenitor cells to migrate toward the sites of injury or tumor formation reveals additional complexities in brain tumorigenesis. Paracrine effects of PDGF in animal models of gliomagenesis, continued adult neurogenesis capable of increasing in response to brain injury, and the growth factor-rich environment of brain tumors suggest that recruitment may play a role in gliomagenesis. In this view, glioma formation involves recruitment of cells from the adjacent brain and possibly other sites.