Brain-derived neurotrophic factor produced by human umbilical tissue-derived cells is required for its effect on hippocampal dendritic differentiation

Classification and Characteristics of Mesenchymal Stem Cells and Its Potential Therapeutic Mechanisms and Applications against Ischemic Stroke

Ischemic stroke is a serious cerebral disease that often induces death and long-term disability. As a currently available therapy for recanalization after ischemic stroke, thrombolysis, including intravenous thrombolysis and endovascular therapy, still cannot be applicable to all patients due to the narrow time window. Mesenchymal stem cell (MSC) transplantation therapy, which can trigger neuronal regeneration and repair, has been considered as a significant advance in treatment of ischemic stroke. MSC transplantation therapy has exhibited its potential to improve the neurological function in ischemic stroke. Our review describes the current progress and future perspective of MSC transplantation therapy in ischemic stroke treatment, including cell types, transplantation approaches, therapeutic mechanisms, and preliminary clinical trials of MSC transplantation, for providing us an update role of MSC transplantation in ischemic stroke treatment.

Cell-based therapies for retinal diseases: a review of clinical trials and direct to consumer "cell therapy" clinics

Background

The retinal pigment epithelium (RPE) is implicated in the pathophysiology of many retinal degenerative diseases. This cell layer is also an ideal target for cell-based therapies. Several early phase clinical trials evaluating cell therapy approaches for diseases involving the RPE, such as age-related macular degeneration and Stargardt's macular dystrophy have been published. However, there have also been numerous reports of complications from unproven “cell therapy” treatments marketed by “cell therapy” clinics. This review aims to outline the particular approaches in the different published clinical trials for cell-based therapies for retinal diseases. Additionally, the controversies surrounding experimental treatments offered outside of legitimate studies are presented.

Main body

Cell-based therapies can be applied to disorders that involve the RPE via a variety of techniques. A defining characteristic of any cell therapy treatment is the cell source used: human embryonic stem cells, induced pluripotent stem cells, and human umbilical tissue-derived cells have all been studied in published trials. In addition to the cell source, various trials have evaluated particular immunosuppression regiments, surgical approaches, and outcome measures. Data from early phase studies investigating cell-based therapies in non-neovascular age-related macular degeneration (70 patients, five trials), neovascular age-related macular degeneration (12 patients, four trials), and Stargardt’s macular dystrophy (23 patients, three trials) have demonstrated safety related to the cell therapies, though evidence of significant efficacy has not been reported. This is in contrast to the multiple reports of serious complications and permanent vision loss in patients treated at “cell therapy” clinics. These interventions are marketed directly to patients, funded by the patient, lack Food and Drug Administration approval, and lack significant oversight.

Conclusion

Currently, there are no proven effective cell-based treatments for retinal diseases, although several trials have investigated potential therapies. These studies reported favorable safety profiles with multiple surgical approaches, with cells derived from multiple sources, and with utilized different immunosuppressive regiments. However, data demonstrating the efficacy and long-term safety are still pending. Nevertheless, “cell therapy” clinics continue to conduct direct-to consumer marketing for non-FDA-approved treatments with potentially blinding complications.

Cell based therapy reduces secondary damage and increases extent of microglial activation following cortical injury

Cortical injury elicits long-term cytotoxic and cytoprotective mechanisms within the brain and the balance of these pathways can determine the functional outcome for the individual. Cytotoxicity is exacerbated by production of reactive oxygen species, accumulation of iron, and peroxidation of cell membranes and myelin. There are currently no neurorestorative treatments to aid in balancing the cytotoxic and cytoprotective mechanisms following cortical injury. Cell based therapies are an emerging treatment that may function in immunomodulation, reduction of secondary damage, and reorganization of surviving structures. We previously evaluated human umbilical tissue-derived cells (hUTC) in our non-human primate model of cortical injury restricted to the hand area of primary motor cortex. Systemic hUTC treatment resulted in significantly greater recovery of fine motor function compared to vehicle controls. Here we investigate the hypothesis that hUTC treatment reduces oxidative damage and iron accumulation and increases the extent of the microglial response to cortical injury. To test this, brain sections from these monkeys were processed using immunohistochemistry to quantify oxidative damage (4-HNE) and activated microglia (LN3), and Prussian Blue to quantify iron. hUTC treated subjects exhibited significantly reduced oxidative damage in the sublesional white matter and iron accumulation in the perilesional area as well as a significant increase in the extent of activated microglia along white matter pathways. Increased perilesional iron accumulation was associated with greater perilesional oxidative damage and larger reconstructed lesion volume. These findings support the hypothesis that systemic hUTC administered 24 h after cortical damage decreases the cytotoxic response while increasing the extent of microglial activation.

Endocytic Adaptor Protein HIP1R Controls Intracellular Trafficking of Epidermal Growth Factor Receptor in Neuronal Dendritic Development

Huntington-interacting protein 1-related protein (HIP1R) was identified on the basis of its structural homology with HIP1. Based on its domain structure, HIP1R is a putative endocytosis-related protein. Our previous study had shown that knockdown of HIP1R induces a dramatic decrease of dendritic growth and branching in cultured rat hippocampal neurons. However, the underlying mechanism remains elucidative. In this study, we found that knockdown of HIP1R impaired the endocytosis of activated epidermal growth factor receptor (EGFR) and the consequent activation of the downstream ERK and Akt proteins. Meanwhile, it blocked the EGF-induced dendritic outgrowth. We also showed that the HIP1R fragment, amino acids 633–822 (HIP1R_633–822), interacted with EGFR and revealed a dominant negative effect in disrupting the HIP1R-EGFR interaction-mediated neuronal development. Collectively, these results reveal a novel mechanism that HIP1R plays a critical role in neurite initiation and dendritic branching in cultured hippocampal neurons via mediating the endocytosis of EGFR and downstream signaling.

Transplanting Mesenchymal Stem Cells for Treatment of Ischemic Stroke

Stroke is a major disease that leads to high mortality and morbidity. Given the ageing population and the potential risk factors, the prevalence of stroke and socioeconomic burden associated with stroke are expected to increase. During the past decade, both prophylactic and therapeutic strategies for stroke have made significant progress. However, current therapies still cannot adequately improve the outcomes of stroke and may not apply to all patients. One of the significant advances in modern medicine is cell-derived neurovascular regeneration and neuronal repair. Progress in stem cell biology has greatly contributed to ameliorating stroke-related brain injuries in preclinical studies and demonstrated clinical potential in stroke treatment. Mesenchymal stem cells (MSCs) have the differentiating potential of chondrocytes, adipocytes, and osteoblasts, and they have the ability to transdifferentiate into endothelial cells, glial cells, and neurons. Due to their great plasticity, MSCs have drawn much attention from the scientific community. This review will focus on MSCs, stem cells widely utilized in current medical research, and evaluate their effect and potential of improving outcomes in ischemic stroke.

Subretinal Human Umbilical Tissue-Derived Cell Transplantation Preserves Retinal Synaptic Connectivity and Attenuates Müller Glial Reactivity

Human umbilical tissue-derived cells (hUTC or palucorcel) are currently under clinical investigation for the treatment of geographic atrophy, a late stage of macular degeneration, but how hUTC transplantation mediates vision recovery is not fully elucidated. Subretinal administration of hUTC preserves visual function in the Royal College of Surgeons (RCS) rat, a genetic model of retinal degeneration caused by Mertk loss of function. hUTC secrete synaptogenic and neurotrophic factors that improve the health and connectivity of the neural retina. Therefore, we investigated the progression of synapse and photoreceptor loss and whether hUTC treatment preserves photoreceptors and synaptic connectivity in the RCS rats of both sexes. We found that RCS retinas display significant deficits in synaptic development already by postnatal day 21 (P21), before the onset of photoreceptor degeneration. Subretinal transplantation of hUTC at P21 is necessary to rescue visual function in RCS rats, and the therapeutic effect is enhanced with repeated injections. Synaptic development defects occurred concurrently with morphological changes in Müller glia, the major perisynaptic glia in the retina. hUTC transplantation strongly diminished Müller glia reactivity and specifically protected the α2δ-1-containing retinal synapses, which are responsive to thrombospondin family synaptogenic proteins secreted by Müller glia. Müller glial reactivity and reduced synaptogenesis observed in RCS retinas could be recapitulated by CRISPR/Cas9-mediated loss-of-Mertk in Müller glia in wild-type rats. Together, our results show that hUTC transplantation supports the health of retina at least in part by preserving the functions of Müller glial cells, revealing a previously unknown aspect of hUTC transplantation-based therapy.SIGNIFICANCE STATEMENT Despite the promising effects observed in clinical trials and preclinical studies, how subretinal human umbilical tissue-derived cell (hUTC) transplantation mediates vision improvements is not fully known. Using a rat model of retinal degeneration, the RCS rat (lacking Mertk), here we provide evidence that hUTC transplantation protects visual function and health by protecting photoreceptors and preserving retinal synaptic connectivity. Furthermore, we find that loss of Mertk function only in Müller glia is sufficient to impair synaptic development and cause activation of Müller glia. hUTC transplantation strongly attenuates the reactivity of Müller glia in RCS rats. These findings highlight novel cellular and molecular mechanisms within the neural retina, which underlie disease mechanisms and pinpoint Müller glia as a novel cellular target for hUTC transplantation.

The 3' UTRs of Brain-Derived Neurotrophic Factor Transcripts Differentially Regulate the Dendritic Arbor

The patterning of dendrites is regulated by many factors, such as brain-derived neurotrophic factor (BDNF), which our laboratory has previously shown alters the dendritic arbor uniquely depending on the mode of extracellular application. In the current work, we examine how BDNF affects dendritogenesis in hippocampal neurons when it is overexpressed intracellularly by transcripts previously reported to be transported to distinct cellular compartments. The BDNF gene is processed at two different polyadenylation sites, leading to mRNA transcription with two different length 3′ untranslated regions (UTRs), and therefore, different mRNA localization preferences. We found that overexpression of BDNF mRNA with or without 3′ UTRs significantly alters dendritic branching compared to branching in control neurons as analyzed by Sholl distribution curves. Unexpectedly, we found that the overexpression of the shorter BDNF mRNA (reported to be preferentially targeted to the cell body) results in similar changes to Sholl curves compared to overexpression of the longer BDNF mRNA (reported to be preferentially targeted to both the cell body and dendrites). We also investigated whether the BDNF receptor TrkB mediates these changes and found that inhibiting TrkB blocks increases in Sholl curves, although at different distances depending on the transcript’s UTR. Finally, although it is not found in nature, we also examined the effects of overexpressing BDNF mRNA with the unique portion of the longer 3′ UTR since it was previously shown to be necessary for dendritic targeting of mRNA. We found that its overexpression increases Sholl curves at distances close to the cell body and that these changes also depend on TrkB activity. This work illustrates how the mRNA spatial code affects how BDNF alters local dendritogenesis and how TrkB may mediate these effects. Finally, our findings emphasize the importance of intracellular transport of BDNF mRNAs in the regulation of dendrite morphology.

Distinct effects on the dendritic arbor occur by microbead versus bath administration of brain-derived neurotrophic factor

Proper communication among neurons depends on an appropriately formed dendritic arbor, and thus, aberrant changes to the arbor are implicated in many pathologies, ranging from cognitive disorders to neurodegenerative diseases. Due to the importance of dendritic shape to neuronal network function, the morphology of dendrites is tightly controlled and is influenced by both intrinsic and extrinsic factors. In this work, we examine how brain-derived neurotrophic factor (BDNF), one of the most well-studied extrinsic regulators of dendritic branching, affects the arbor when it is applied locally via microbeads to cultures of hippocampal neurons. We found that local application of BDNF increases both proximal and distal branching in a time-dependent manner and that local BDNF application attenuates pruning of dendrites that occurs with neuronal maturation. Additionally, we examined whether cytosolic PSD-95 interactor (cypin), an intrinsic regulator of dendritic branching, plays a role in these changes and found strong evidence for the involvement of cypin in BDNF-promoted increases in dendrites after 24 but not 48 h of application. This current study extends our previous work in which we found that bath application of BDNF for 72 h, but not shorter times, increases proximal dendrite branching and that this increase occurs through transcriptional regulation of cypin. Moreover, this current work illustrates how dendritic branching is regulated differently by the same growth factor depending on its spatial localization, suggesting a novel pathway for modulation of dendritic branching locally.

Experience With a Subretinal Cell-based Therapy in Patients With Geographic Atrophy Secondary to Age-related Macular Degeneration

PURPOSE

To evaluate the safety and tolerability of and clinical response to a single, subretinal dose of human umbilical tissue-derived cells (palucorcel [CNTO-2476]) in the eyes of adults aged ≥50 years with bilateral geographic atrophy (GA) secondary to age-related macular degeneration (AMD).

DESIGN

Phase 1/2a, multicenter, open-label, dose-escalation, fellow-eye-controlled study.

METHODS

In the phase 1 portion, eyes were assigned to receive a single, subretinal dose of palucorcel (ranging from 6.0 × 10⁴ to 5.6 × 10⁵ viable cells). In the phase 2a portion, eyes were assigned to one of 2 palucorcel doses (6.0 × 10⁴ or 3.0 × 10⁵ cells) determined during the phase 1 portion. The intervention eye was the eye with worse baseline visual acuity.

RESULTS

A total of 35 eligible subjects underwent at least a partial surgical procedure. Palucorcel was administered in 33 eyes. Overall, 17.1% (6/35) of subjects experienced retinal detachments and 37.1% (13/35) experienced retinal perforations. No episodes of immune rejection or tumor formation were observed. At 1 year, ≥10- and ≥15-letter gains in best-corrected visual acuity were observed in 34.5% (10/29) and 24.1% (7/29) of eyes receiving palucorcel, respectively, and in 3.3% (1/30; for both) of fellow eyes.

CONCLUSIONS

The subretinal delivery procedure in this study was associated with a high rate of retinal perforations (n = 13) and retinal detachments (n = 6). When cells were sequestered in the subretinal space, palucorcel was well tolerated and may be associated with improvements in visual acuity. Larger randomized controlled studies are required to confirm these results. Future studies would require a modified surgical approach.

Mesenchymal Stromal Cells Promote Axonal Outgrowth Alone and Synergistically with Astrocytes via tPA

We reported that mesenchymal stromal cells (MSCs) enhance neurological recovery from experimental stroke and increase tissue plasminogen activator (tPA) expression in astrocytes. Here, we investigate mechanisms by which tPA mediates MSC enhanced axonal outgrowth. Primary murine neurons and astrocytes were isolated from wild-type (WT) and tPA-knockout (KO) cortices of embryos. Mouse MSCs (WT) were purchased from Cognate Inc. Neurons (WT or KO) were seeded in soma side of Xona microfluidic chambers, and astrocytes (WT or KO) and/or MSCs in axon side. The chambers were cultured as usual (normoxia) or subjected to oxygen deprivation. Primary neurons (seeded in plates) were co-cultured with astrocytes and/or MSCs (in inserts) for Western blot. In chambers, WT axons grew significantly longer than KO axons and exogenous tPA enhanced axonal outgrowth. MSCs increased WT axonal outgrowth alone and synergistically with WT astrocytes at both normoxia and oxygen deprivation conditions. The synergistic effect was inhibited by U0126, an ERK inhibitor, and receptor associated protein (RAP), a low density lipoprotein receptor related protein 1 (LRP1) ligand antagonist. However, MSCs exerted neither individual nor synergistic effects on KO axonal outgrowth. Western blot showed that MSCs promoted astrocytic tPA expression and increased neuronal tPA alone and synergistically with astrocytes. Also, MSCs activated neuronal ERK alone and synergistically with astrocytes, which was inhibited by RAP. We conclude: (1) MSCs promote axonal outgrowth via neuronal tPA and synergistically with astrocytic tPA; (2) neuronal tPA is critical to observe the synergistic effect of MSC and astrocytes on axonal outgrowth; and (3) tPA mediates MSC treatment-induced axonal outgrowth through the LRP1 receptor and ERK.

Astroglial Activation by an Enriched Environment after Transplantation of Mesenchymal Stem Cells Enhances Angiogenesis after Hypoxic-Ischemic Brain Injury

Transplantation of mesenchymal stem cells (MSCs) has paracrine effects; however, the effects are known to be largely limited. Here we investigated the combination effects of cell transplantation and enriched environment (EE) in a model of hypoxic-ischemic brain injury. Brain damage was induced in seven-day-old mice by unilateral carotid artery ligation and exposure to hypoxia (8% O₂ for 90 min). At six weeks of age, the mice were randomly assigned to four groups: phosphate-buffered saline (PBS)-control (CON), PBS-EE, MSC-CON, and MSC-EE. Rotarod and grip strength tests were performed to evaluate neurobehavioral functions. Histologic evaluations were also performed to confirm the extent of astrocyte activation and endogenous angiogenesis. An array-based multiplex ELISA and Western blot were used to identify growth factors in vivo and in vitro. Two weeks after treatment, levels of astrocyte density and angiogenic factors were increased in MSC-EE mice, but glial scarring was not increased. Eight weeks after treatment, angiogenesis was increased, and behavioral outcomes were synergistically improved in the MSC-EE group. Astrocytes co-cultured with MSCs expressed higher levels of angiogenic factors than astrocytes cultured alone. The mechanisms of this synergistic effect included enhanced repair processes, such as increased endogenous angiogenesis and upregulation of angiogenic factors released from activated astrocytes.

Human Umbilical Tissue-Derived Cells Promote Synapse Formation and Neurite Outgrowth via Thrombospondin Family Proteins

Cell therapy demonstrates great potential for the treatment of neurological disorders. Human umbilical tissue-derived cells (hUTCs) were previously shown to have protective and regenerative effects in animal models of stroke and retinal degeneration, but the underlying therapeutic mechanisms are unknown. Because synaptic dysfunction, synapse loss, degeneration of neuronal processes, and neuronal death are hallmarks of neurological diseases and retinal degenerations, we tested whether hUTCs contribute to tissue repair and regeneration by stimulating synapse formation, neurite outgrowth, and neuronal survival. To do so, we used a purified rat retinal ganglion cell culture system and found that hUTCs secrete factors that strongly promote excitatory synaptic connectivity and enhance neuronal survival. Additionally, we demonstrated that hUTCs support neurite outgrowth under normal culture conditions and in the presence of the growth-inhibitory proteins chondroitin sulfate proteoglycan, myelin basic protein, or Nogo-A (reticulon 4). Furthermore, through biochemical fractionation and pharmacology, we identified the major hUTC-secreted synaptogenic factors as the thrombospondin family proteins (TSPs), TSP1, TSP2, and TSP4. Silencing TSP expression in hUTCs, using small RNA interference, eliminated both the synaptogenic function of these cells and their ability to promote neurite outgrowth. However, the majority of the prosurvival functions of hUTC-conditioned media was spared after TSP knockdown, indicating that hUTCs secrete additional neurotrophic factors. Together, our findings demonstrate that hUTCs affect multiple aspects of neuronal health and connectivity through secreted factors, and each of these paracrine effects may individually contribute to the therapeutic function of these cells.

SIGNIFICANCE STATEMENT

Human umbilical tissue-derived cells (hUTC) are currently under clinical investigation for the treatment of geographic atrophy secondary to age-related macular degeneration. These cells show great promise for the treatment of neurological disorders; however, the therapeutic effects of these cells on CNS neurons are not fully understood. Here we provide compelling evidence that hUTCs secrete multiple factors that work synergistically to enhance synapse formation and function, and support neuronal growth and survival. Moreover, we identified thrombospondins (TSPs) as the hUTC-secreted factors that mediate the synaptogenic and growth-promoting functions of these cells. Our findings highlight novel paracrine effects of hUTC on CNS neuron health and connectivity and begin to unravel potential therapeutic mechanisms by which these cells elicit their effects.

The potential use of mesenchymal stem cells in stroke therapy--From bench to bedside

Stroke is the second main cause of morbidity and mortality worldwide. The rationale for the use of mesenchymal stem cells (MSCs) in stroke is based on the capacity of MSCs to secrete a large variety of bioactive molecules such as growth factors, cytokines and chemokines leading to reduction of inflammation, increased neurogenesis from the germinative niches of central nervous system, increased angiogenesis, effects on astrocytes, oligodendrocytes and axons. This review presents the data derived from experimental studies and the evidence available from clinical trials about the use of MSCs in stroke therapy.

Serotonin dysregulation in Fragile X Syndrome: implications for treatment

Fragile X Syndrome (FXS) is a trinucleotide repeat disorder that results in the silencing of the Fragile X Mental Retardation 1 gene (FMR1), leading to a lack of the FMR1 protein (FMRP). FMRP is an mRNA-binding protein that regulates the translation of hundreds of mRNAs important for synaptic plasticity. Several of these pathways have been identified and have guided the development of targeted treatments for FXS. Here we present evidence that serotonin is dysregulated in FXS and treatment with the selective serotonin reuptake inhibitor (SSRI) sertraline may be beneficial for individuals with FXS, particularly in early childhood.

Bone Marrow Stromal Cells Rescue Ischemic Brain by Trophic Effects and Phenotypic Change Toward Neural Cells

Background. Transplantation of bone marrow stromal cells (BMSCs) may contribute to functional recovery after stroke. This study was designed to clarify their mechanisms, trophic effects of neurotrophic factors, and neural differentiation. Methods. Mouse neurons exposed to glutamate were cocultured with mouse BMSCs. Either neutralizing antibodies against brain-derived neurotrophic factor (BDNF) or nerve growth factor (NGF) or Trk inhibitor K252a was added to explore the mechanism of their protective effects. Fluorescence in situ hybridization (FISH) was used to assess BDNF or NGF mRNA expression in BMSCs. The mice were subjected to permanent focal ischemia, and 7 days later, either BMSCs or the vehicle was stereotactically transplanted into the ipsilateral striatum. The mouse brains were processed for FISH and immunostaining 2 or 4 weeks after transplantation. Results. BMSCs significantly ameliorated glutamate-induced neuronal death. Treatment with anti-BDNF antibody significantly reduced their protective effects. FISH analysis showed that the majority of BMSCs expressed BDNF and NGF mRNA in vitro. BMSC transplantation significantly improved the survival of neurons in peri-infarct areas. FISH analysis revealed that approximately half of BMSCs expressed BDNF and NGF mRNA 2 weeks after transplantation; however, the percentage of BDNF and NGF mRNA-positive cells decreased thereafter. Instead, the percentage of microtubule-associated protein 2–positive BMSCs gradually increased during 4 weeks after transplantation. Conclusions. These findings strongly suggest that BDNF may be a key factor underlying the trophic effects of BMSCs. BMSCs might exhibit the trophic effect in the early stage of cell therapy and the phenotypic change toward neural cells thereafter.

Neural differentiation and support of neuroregeneration of non-neural adult stem cells

Although it is well established that neural stem cells (NSCs) or neural stem/progenitor cells differentiated from pluripotent stem cells can generate neurons, astrocytes, and oligodendrocytes, a number of other cell populations are also being considered for therapy of central nervous system disorders. Here, we describe the potential of (stem) cells from other postnatal tissues, including bone marrow, (umbilical cord) blood, fat tissue, or dental pulp, which themselves do not (robustly) generate neural progeny. However, these non-neuroectoderm derived cell populations appear to capable of inducing endogenous neurogenesis and angiogenesis. As these "trophic" effects are also, at least partly, responsible for some of the beneficial effects seen when NSC are grafted in the brain, these non-neuroectodermal cells may exert beneficial effects when used to treat neurodegenerative disorders.

The role of astrocytes in mediating exogenous cell-based restorative therapy for stroke

Astrocytes have not been a major therapeutic target for the treatment of stroke, with most research emphasis on the neuron. Given the essential role that astrocytes play in maintaining physiological function of the central nervous system and the very rapid and sensitive reaction astrocytes have in response to cerebral injury or ischemic insult, we propose to replace the neurocentric view for treatment with a more nuanced astrocytic centered approach. In addition, after decades of effort in attempting to develop neuroprotective therapies, which target reduction of the ischemic lesion, there are no effective clinical treatments for stroke, aside from thrombolysis with tissue plasminogen activator, which is used in a small minority of patients. A more promising therapeutic approach, which may affect nearly all stroke patients, may be in promoting endogenous restorative mechanisms, which enhance neurological recovery. A focus of efforts in stimulating recovery post stroke is the use of exogenously administered cells. The present review focuses on the role of the astrocyte in mediating the brain network, brain plasticity, and neurological recovery post stroke. As a model to describe the interaction of a restorative cell-based therapy with astrocytes, which drives recovery from stroke, we specifically highlight the subacute treatment of stroke with multipotent mesenchymal stromal cell therapy.

Injection of human umbilical tissue-derived cells into the nucleus pulposus alters the course of intervertebral disc degeneration in vivo

BACKGROUND CONTEXT

Patients often present to spine clinic with evidence of intervertebral disc degeneration (IDD). If conservative management fails, a safe and effective injection directly into the disc might be preferable to the risks and morbidity of surgery.

PURPOSE

To determine whether injecting human umbilical tissue-derived cells (hUTC) into the nucleus pulposus (NP) might improve the course of IDD.

DESIGN

Prospective, randomized, blinded placebo-controlled in vivo study.

PATIENT SAMPLE

Skeletally mature New Zealand white rabbits.

OUTCOME MEASURES

Degree of IDD based on magnetic resonance imaging (MRI), biomechanics, and histology.

METHODS

Thirty skeletally mature New Zealand white rabbits were used in a previously validated rabbit annulotomy model for IDD. Discs L2-L3, L3-L4, and L4-L5 were surgically exposed and punctured to induce degeneration and then 3 weeks later the same discs were injected with hUTC with or without a hydrogel carrier. Serial MRIs obtained at 0, 3, 6, and 12 weeks were analyzed for evidence of degeneration qualitatively and quantitatively via NP area and MRI Index. The rabbits were sacrificed at 12 weeks and discs L4-L5 were analyzed histologically. The L3-L4 discs were fixed to a robotic arm and subjected to uniaxial compression, and viscoelastic displacement curves were generated.

RESULTS

Qualitatively, the MRIs demonstrated no evidence of degeneration in the control group over the course of 12 weeks. The punctured group yielded MRIs with the evidence of disc height loss and darkening, suggestive of degeneration. The three treatment groups (cells alone, carrier alone, or cells+carrier) generated MRIs with less qualitative evidence of degeneration than the punctured group. MRI Index and area for the cell and the cell+carrier groups were significantly distinct from the punctured group at 12 weeks. The carrier group generated MRI data that fell between control and punctured values but failed to reach a statistically significant difference from the punctured values. There were no statistically significant MRI differences among the three treatment groups. The treated groups also demonstrated viscoelastic properties that were distinct from the control and punctured values, with the cell curve more similar to the punctured curve and the carrier curve and carrier+cells curve more similar to the control curve (although no creep differences achieved statistical significance). There was some histological evidence of improved cellularity and disc architecture in the treated discs compared with the punctured discs.

CONCLUSIONS

Treatment of degenerating rabbit intervertebral discs with hUTC in a hydrogel carrier solution might help restore the MRI, histological, and biomechanical properties toward those of nondegenerated controls. Treatment with cells in saline or a hydrogel carrier devoid of cells also might help restore some imaging, architectural, and physical properties to the degenerating disc. These data support the potential use of therapeutic cells in the treatment of disc degeneration.

Efficacy of single and multiple injections of human umbilical tissue-derived cells following experimental stroke in rats

Introduction

Human umbilical tissue-derived cells (hUTC) are a promising source of cells for regenerative treatment of stroke. In this study, we tested the efficacy of hUTC in experimental stroke and whether multiple injections of hUTC provide additional therapeutic benefits as compared to a single injection.

Methods

Adult male Wistar rats were subjected to 2 hours of middle cerebral artery occlusion (MCAo), and randomly selected animals were injected (i.v) with 3×10⁶ hUTC or with vehicle control (at day: 1, 1&3 or 1&7 after MCAo, n = 8–9/group). A battery of functional outcome tests was performed at days 1, 7, 14, 21, 28, 35, 42, 49, 56 and 63 after MCAo. Rats were sacrificed at 63 days after MCAo and lesion volumes were measured. To investigate the underlying mechanism of hUTC treatment of stroke, Von Willebrand Factor (vWF), and Synaptophysin immunostaining were performed.

Results

All hUTC treated groups, single or multiple injections, had better functional recovery compared to control (p<0.01). There was no statistically significant difference between a single and multiple injections of hUTC (p = 0.23) or between different multiple injections groups (p>0.07) in functional outcome. All hUTC treatment groups showed significant increases in Synaptophysin, vascular density and perimeter compared to the control group (p<0.05). There was no statistically significant difference between a single and multiple injections of hUTC or between the two groups of multiple injections in all immunohistochemical measurements (p>0.1).

Conclusion

hUTC treatment significantly improves long term functional outcome after stroke and promotes vascular density and synaptic plasticity. At the proscribed doses, multiple injections of hUTC were not superior to single injection therapy in both functional outcome and histological assessments.

Different routes of administration of human umbilical tissue-derived cells improve functional recovery in the rat after focal cerebral ischemia

Human umbilical tissue-derived cells (hUTC) are a potential neurorestorative candidate for stroke treatment. Here, we test the effects of hUTC treatment in a rat model of stroke via various routes of administration. Rats were treated with hUTC or phosphate-buffered saline (PBS) via different routes including intraarterial (IA), intravenous (IV), intra-cisterna magna (ICM), lumber intrathecal (IT), or intracerebral injection (IC) at 24h after stroke onset. Treatment with hUTC via IV and IC route led to significant functional improvements starting at day 14, which persisted to day 60 compared with respective PBS-treated rats. HUTC administered via IA, ICM, and IT significantly improved neurological functional recovery starting at day 14 and persisted up to day 49 compared with PBS-treated rats. Although IA administration resulted in the highest donor cell number detected within the ischemic brain compared to the other routes, hUTC treatments significantly increased ipsilateral bromodeoxyuridine incorporating subventricular zone (SVZ) cells and vascular density in the ischemic boundary compared with PBS-treated rats regardless of the route of administration. While rats received hUTC treatment via IA, IV, IC, and ICM routes showed greater synaptophysin immunoreactivity, significant reductions in TUNEL-positive cells in the ipsilateral hemisphere were observed in IA, IV, and IC routes compared with PBS-treated rats. hUTC treatments did not reduce infarct volume when compared to the PBS groups. Our data indicate that hUTC administered via multiple routes provide therapeutic benefit after stroke. The enhancement of neurorestorative events in the host brain may contribute to the therapeutic benefits of hUTC in the treatment of stroke.