Umbilical Tissue-derived Cells Research Articles

Neuroprotection for Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is a leading cause of blindness worldwide. Early to intermediate AMD is characterized by the accumulation of lipid- and protein-rich drusen. Late stages of the disease are characterized by the development of choroidal neovascularization, termed "exudative" or "neovascular AMD," or retinal pigment epithelium (RPE) cell and photoreceptor death, termed "geographic atrophy" (GA) in advanced nonexudative AMD. Although we have effective treatments for exudative AMD in the form of anti-VEGF agents, they have no role for patients with GA. Neuroprotection strategies have emerged as a possible way to slow photoreceptor degeneration and vision loss in patients with GA. These approaches include reduction of oxidative stress, modulation of the visual cycle, reduction of toxic molecules, inhibition of pathologic protein activity, prevention of cellular apoptosis or programmed necrosis (necroptosis), inhibition of inflammation, direct activation of neurotrophic factors, delivery of umbilical tissue-derived cells, and RPE replacement. Despite active investigation in this area and significant promise based on preclinical studies, many clinical studies have not yielded successful results. We discuss selected past and current neuroprotection trials for AMD, highlight the lessons learned from these past studies, and discuss our perspective regarding remaining questions that must be answered before neuroprotection can be successfully applied in the field of AMD research.

HLA-G and CD152 Expression Levels Encourage the Use of Umbilical Cord Tissue-Derived Mesenchymal Stromal Cells as an Alternative for Immunosuppressive Therapy.

Mesenchymal stromal cells (MSCs) have been used in immunosuppressive therapy due to their therapeutic effects, with the HLA-G molecule seeming to play a fundamental role. This work evaluated alternative MSC sources to bone marrow (BM), namely, umbilical cord tissue (UC), adipose tissue (AD) and dental pulp tissue (DP), and the influence of interferon-γ (IFN-γ) and hypoxia on the cultivation of these cells for use in immunosuppression therapies. Expression of costimulatory markers CD40, CD80 and CD86 and immunosuppressive molecules CD152 and HLA-G was analyzed. Lymphocyte inhibition assays were also performed. Sequencing of the HLA-G gene from exons 1 to 5 was performed using next-generation sequencing to determine the presence of alleles. UC-derived MSCs (UCMSCs) expressed higher CD152 and HLA-G1 under standard cultivation. UCMSCs and DP-derived MSCs (DPSCs) secreted similar levels of HLA-G5. All MSC sources inhibited the proliferation of peripheral blood mononuclear cells (PBMCs); growth under regular versus hypoxic conditions resulted in similar levels of inhibition. When IFN-γ was added, PBMC growth was inhibited to a lesser extent by UCMSCs. The HLA-G*01:04:01:01 allele appears to generate a more efficient MSC response in inhibiting lymphocyte proliferation. However, the strength of this conclusion was limited by the small sample size. UCMSCs are an excellent alternative to BM in immunosuppressive therapy: they express high concentrations of inhibitory molecules and can be cultivated without stimuli, which minimizes cost.

In vitro evaluation of umbilical cord tissue-derived mesenchymal stromal cells to alleviate occupational lung disease

In vitro evaluation of umbilical cord tissue-derived mesenchymal stromal cells to alleviate occupational lung disease

A Flowable Placental Formulation Prevents Bleomycin-Induced Dermal Fibrosis in Aged Mice.

Fibrosis, the thickening and scarring of injured connective tissue, leads to a loss of organ function. Multiple cell types, including T-cells, macrophages, fibrocytes, and fibroblasts/myofibroblasts contribute to scar formation via secretion of inflammatory factors. This event results in an increase in oxidative stress and deposition of excessive extracellular matrix (ECM), characteristic of fibrosis. Further, aging is known to predispose connective tissue to fibrosis due to reduced tissue regeneration. In this study, we investigated the anti-fibrotic activity of a flowable placental formulation (FPF) using a bleomycin-induced dermal fibrosis model in aged mice. FPF consisted of placental amnion/chorion- and umbilical tissue-derived ECM and cells. The mice were injected with either FPF or PBS, followed by multiple doses of bleomycin. Histological assessment of FPF-treated skin samples revealed reduced dermal fibrosis, inflammation, and TGF-β signaling compared to the control group. Quantitative RT-PCR and Next Generation Sequencing analysis of miRNAs further confirmed anti-fibrotic changes in the FPF-treated group at both the gene and transcriptional levels. The observed modulation in miRNAs was associated with inflammation, TGF-β signaling, fibroblast proliferation, epithelial-mesenchymal transition and ECM deposition. These results demonstrate the potential of FPF in preventing fibrosis and may be of therapeutic benefit for those at higher risk of fibrosis due to wounds, aging, exposure to radiation and genetic predisposition.

Safety and Efficacy of Subretinally Administered Palucorcel for Geographic Atrophy of Age-Related Macular Degeneration: Phase 2b Study

To evaluate safety and successful use of a novel subretinal delivery system and suprachoroidal surgical approach and safety and activity of human umbilical tissue-derived cells (palucorcel) via a novel delivery system in patients with geographic atrophy (GA). Multicenter, open-label phase 2b study. Participants were 55 to 90 years with GA secondary to age-related macular degeneration (AMD) and best-corrected visual acuity (BCVA) of 20/80 to 20/800. Exclusion criteria included neovascular AMD in the intervention eye, glaucoma with intraocular pressure of 25 mmHg or more, or other significant ophthalmologic conditions. Participants received a subretinal injection of palucorcel, 3.0× 105 cells in 50 μl, using the custom-designed delivery system and surgical procedure. Safety assessments included treatment-emergent adverse events (AEs), immunologic assessments, and ophthalmologic evaluations. Efficacy was evaluated as change in mean number of BCVA letters from baseline, proportion of participants gaining 15 BCVA letters or more, and growth rate of GA lesions at 12 months. Surgery and palucorcel administration were performed in 21 participants at 8 sites by 8 different surgeons. At baseline, median total area of GA was 13.4 mm2 and median BCVA was 43 letters in the intervention eye. Eye-related AEs occurred in 76% of participants (16/21), including conjunctival hemorrhage (n= 5), retinal hemorrhage (n= 4), and vitreous floaters (n= 4). Most AEs were mild and resolved within 1 month. No serious AEs, no retinal detachment or perforation, and no significant changes in intraocular pressure occurred. At month 12, mean change in BCVA from baseline was -5.9 letters correct (standard deviation, 13.0 letters correct) in the intervention eye and -3.7 letters correct (standard deviation, 9.0 letters correct) in the fellow eye. No participants showed improvement of 15 letters or more in the intervention eye, and 3 participants lost more than 15 letters by month 1. No apparent effect of treatment was observed. Palucorcel was delivered successfully to the targeted subretinal site using a novel delivery system and suprachoroidal approach for most participants; however, improvement in GA area, retardation of growth, or visual acuity were not demonstrated.

Human Umbilical Tissue-Derived Cells Secrete Soluble VEGFR1 and Inhibit Choroidal Neovascularization

Exudative age-related macular degeneration (AMD), characterized by choroidal neovascularization (CNV), is the leading cause of irreversible blindness in developed countries. Anti-vascular endothelial growth factor (VEGF) drugs are the standard treatment for AMD, but they have limitations. Cell therapy is a promising approach for ocular diseases, and it is being developed in the clinic for the treatment of retinal degeneration, including AMD. We previously showed that subretinal injection of human umbilical tissue-derived cells (hUTCs) in a rodent model of retinal degeneration preserved photoreceptors and visual function through rescue of retinal pigment epithelial (RPE) cell phagocytosis. Here we investigated the effect of hUTCs on a rat model of laser-induced CNV and on a human RPE cell line, ARPE-19, for VEGF production. We demonstrate that subretinal injection of hUTCs significantly inhibited CNV and lowered choroidal VEGF in vivo. VEGF release from ARPE-19 decreased when co-cultured with hUTCs. Soluble VEGF receptor 1 (sVEGFR1) is identified as the only factor in hUTC conditioned medium (CM) that binds to VEGF. The level of exogenous recombinant VEGF in hUTC CM was dramatically reduced and could be recovered with sVEGFR1-neutralizing antibody. This suggests that hUTC inhibits angiogenesis through the secretion of sVEGFR1 and could serve as a novel treatment for angiogenic ocular diseases, including AMD.

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.

Retraction Note: Umbilical cord tissue-derived mesenchymal stem cells induce apoptosis in PC-3 prostate cancer cells through activation of JNK and downregulation of PI3K/AKT signaling

This article [1] has been retracted by the authors because, contrary to the statement in the article, ethical approval was not obtained to conduct this study.

Human umbilical cord tissue stem cells and neuronal lineages in an injectable caffeic acid-bioconjugated gelatin hydrogel for transplantation.

Present-day scaffolds are useful in cell therapy to a reasonable extent, but in pursuit of improvising the scaffold to improve the outcome, we tested a new injectable caffeic acid-bioconjugated gelatin hydrogel scaffold (CBGH; with tunable stiffness -10%). Two-dimensional (2D) form of human umbilical cord tissue-derived mesenchymal stem cells (HUCMSCs) culture performed based on our previously reported methods and characterized by using multipotent and pluripotent analysis. In addition, neurogenesis was induced in the presence of retinoic acid or neural growth factor or epidermal growth factor categorized by neuronal markers. The viability, proliferation rate, and vascular endothelial growth factor expression of HUCMSCs increased significantly in the CBGH scaffold. In addition, there was an increase in CD90 and TRA-1-81 phenotypic expressions and SOX-2, MAP-2, TAU, NeuN, and NF, which confirmed the neurogenesis of encapsulated HUCMSCs. Topographical elucidation by scanning electron microscopy data showed that the HUCMSCs proliferated and migrated inside the construct. Hematoxylin and eosin staining demonstrated a more viable structural pattern and cresyl violet staining showed the Nissl synthesis, confirming the presence of functional neurons in the encapsulated form. The molecular-level analysis further substantiated that HUCMSCs cultured in CBGH expressed significantly greater upregulation of stemness, neuronal genes, and protein expression compared with the adherent culture. Correspondingly, this is the first time that we have measured the fluorescence intensity variation of the HUCMSCs-stained cell segmentation process using customized MATLAB code execution to reduce the background noise and autofluorescence. We conclude that this novel CBGH scaffold increases the viability, proliferation, stemness, and also neuronal transdifferentiation of HUCMSCs in a three-dimensional culture than the 2D plastic adherent culture.

Cell based therapy enhances activation of ventral premotor cortex to improve recovery following primary motor cortex injury

Stroke results in enduring damage to the brain which is accompanied by innate neurorestorative processes, such as reorganization of surviving circuits. Nevertheless, patients are often left with permanent residual impairments. Cell based therapy is an emerging therapeutic that may function to enhance the innate neurorestorative capacity of the brain. We previously evaluated human umbilical tissue-derived cells (hUTC) in our non-human primate model of cortical injury limited to the hand area of primary motor cortex. Injection of hUTC 24 h after injury resulted in significantly enhanced recovery of fine motor function compared to vehicle treated controls (Moore et al., 2013). These monkeys also received an injection of Bromodeoxyuridine (BrdU) 8 days after cortical injury to label cells undergoing replication. This was followed by 12 weeks of behavioral testing, which culminated 3 h prior to perfusion in a final behavioral testing session using only the impaired hand. In this session, the neuronal activity initiating hand movements leads to the upregulation of the immediate early gene c-Fos in activated cells. Following perfusion-fixation of the brain, sections were processed using immunohistochemistry to label c-Fos activated cells, pre-synaptic vesicle protein synaptophysin, and BrdU labeled neuroprogenitor cells to investigate the hypothesis that hUTC treatment enhanced behavioral recovery by facilitating reorganization of surviving cortical tissues. Quantitative analysis revealed that c-Fos activated cells were significantly increased in the ipsi- and contra-lesional ventral premotor but not the dorsal premotor cortices in the hUTC treated monkeys compared to placebo controls. Furthermore, the increase in c-Fos activated cells in the ipsi- and contra-lesional ventral premotor cortex correlated with a decrease in recovery time and improved grasp topography. Interestingly, there was no difference between treatment groups in the number of synaptophysin positive puncta in either ipsi- or contra-lesional ventral or dorsal premotor cortices. Nor was there a significant difference in the density of BrdU labeled cells in the subgranular zone of the hippocampus or the subventricular zone of the lateral ventricle. These findings support the hypothesis that hUTC treatment enhances the capacity of the brain to reorganize after cortical injury and that bilateral plasticity in ventral premotor cortex is a critical locus for this recovery of function. This reorganization may be accomplished through enhanced activation of pre-existing circuits within ventral premotor, but it could also reflect ventral premotor projections to the brainstem or spinal cord.

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.

A Subretinal Cell Delivery Method via Suprachoroidal Access in Minipigs: Safety and Surgical Outcomes.

This study evaluated a new subretinal method for delivery of human or pig umbilical tissue-derived cells (hUTC or pUTC, respectively) using a novel subretinal injection cannula and suprachoroidal approach in Göttingen minipig eyes. hUTC (palucorcel) are currently under development for treating geographic atrophy in humans. Twenty-four Göttingen minipigs (divided into eight groups) were subretinally administered palucorcel, pUTC, or vehicle. In some cases, fluorescently labeled cells and vehicle were administered. Conjunctival cutdown and sclerotomy were performed, then a flexible cannula containing a microneedle was inserted and advanced into the suprachoroidal space. The microneedle was deployed and visualized; 50 μL cells (target concentration, 11.2 × 106 cells/mL [560,000 cells/eye]) or vehicle was injected subretinally. Safety outcomes were evaluated. For all animals, cells and vehicle were successfully administered. Labeled cells or fluorescent vehicle were contained in the subretinal bleb, without leakage into the vitreous. No retinal detachment or vitreous traction band was identified by ophthalmologic examination. At all time points, observed microscopic changes were attributable to experimental procedures. On histopathology immediately after injection, localized retinal detachments were seen, along with focal retinal, choroidal, and/or scleral discontinuities. A moderate inflammatory response was seen in a limited number of animals. In the allogeneic setting, no antibody responses were detectable. Anti-human UTC antibodies were detected in the xenogeneic setting. Palucorcel, pUTC, and vehicle were successfully administered to Göttingen minipigs using a novel subretinal injection cannula via a suprachoroidal surgical approach, with no significant adverse events; therefore, this technique appears to be feasible for further clinical development.

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

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

Abstract WP112: Residual Damage is Reduced Following Human Umbilical Tissue Derived Cell Infusion in a Non-human Primate Model of Cortical Injury

Introduction: Stroke is the leading cause of long-term disability in the United States due to impairments that endure after brain injury. While studies in rodent models have evaluated numerous neurorestorative treatments following stroke, none have received FDA approval. We evaluated a therapy using human umbilical tissue-derived cells (hUTC) as a potential neurorestorative treatment in our non-human primate model of cortical injury limited to the hand area of primary motor cortex. Given treatment 24 hours after injury, hUTC treated monkeys showed a significantly greater degree of recovery of fine motor function compared to vehicle treated controls (Moore et al., 2013). To explore the effect of hUTC, histopathological markers of inflammation and oxidative stress were assessed. Hypothesis: Treatment with hUTC will enhance the recruitment of glia to the injury and reduce the cascade of inflammation and oxidative stress. Methods: Using immunohistochemistry, activated microglia (LN3), reactive astrocytes (GFAP), oxidative damage (4HNE), and accumulated hemosiderin (Perls’ Prussian Blue) were quantified in ipsilesional primary motor cortex and underlying white matter. Microglia were counted using unbiased stereology. A Sholl Analysis was performed on traced perilesional astrocytes. The area of oxidative damage and hemosiderin was assessed using densitometry. Results: Compared to vehicle controls, density of activated microglia in the hUTC treated group approached a significant increase in the perilesional gray and white matter (p=0.070; p=0.092). Astrocytes exhibited more complex processes in treated monkeys (p=0.042). Staining for 4HNE was significantly reduced in white matter underlying the lesion in treated monkeys (p=0.033). Lastly, both the area and intensity of Perls’ staining for hemosiderin was significantly reduced in the perilesional area of treated monkeys (p=0.045; p=0.001). Conclusions: Treatment with hUTC resulted in increased activation of microglia and complexity of reactive astrocyte processes as well as reduced post-lesion oxidative damage and hemosiderin deposition. This suggests the hUTC treatment enhanced recovery, in part, by recruitment of glial cells that limited the damage following cortical injury.

Human umbilical tissue-derived cells rescue retinal pigment epithelium dysfunction in retinal degeneration.

Retinal pigment epithelium (RPE) cells perform many functions crucial for retinal preservation and vision. RPE cell dysfunction results in various retinal degenerative diseases, such as retinitis pigmentosa and age-related macular degeneration (AMD). Currently, there are no effective treatments for retinal degeneration except for a small percentage of individuals with exudative AMD. Cell therapies targeting RPE cells are being developed in the clinic for the treatment of retinal degeneration. Subretinal injection of human umbilical tissue-derived cells (hUTC) in the Royal College of Surgeons (RCS) rat model of retinal degeneration was shown to preserve photoreceptors and visual function. However, the precise mechanism remains unclear. Here, we demonstrate that hUTC rescue phagocytic dysfunction in RCS RPE cells in vitro. hUTC secrete receptor tyrosine kinase (RTK) ligands brain-derived neurotrophic factor (BDNF), hepatocyte growth factor (HGF), and glial cell-derived neurotrophic factor (GDNF), as well as opsonizing bridge molecules milk-fat-globule-epidermal growth factor 8 (MFG-E8), growth arrest-specific 6 (Gas6), thrombospondin (TSP)-1, and TSP-2. The effect of hUTC on phagocytosis rescue in vitro is mimicked by recombinant human proteins of these factors and is abolished by siRNA-targeted gene silencing in hUTC. The bridge molecules secreted from hUTC bind to the photoreceptor outer segments and facilitate their ingestion by the RPE. This study elucidates novel cellular mechanisms for the repair of RPE function in retinal degeneration through RTK ligands and bridge molecules, and demonstrates the potential of using hUTC for the treatment of retinal degenerative diseases.

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

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.

Efficacy of Single and Multiple Injections of Human Umbilical Tissue-Derived Cells Following Experimental Stroke in Rats (S45.007)

Efficacy of Single and Multiple Injections of Human Umbilical Tissue-Derived Cells Following Experimental Stroke in Rats (S45.007)

Intravenous Administration of Human Umbilical Tissue-Derived Cells Improves Neurological Function in Aged Rats after Embolic Stroke

Intravenous administration of human umbilical tissue-derived cells (hUTC) improves neurological function in young adult rats after stroke. However, stroke is a major cause of death and disability in the aged population, with the majority of stroke patients 65 years and older. The present study investigated the effect of hUTC on aged rats after embolic stroke. Rats at the age of 18-20 months were subjected to embolic middle cerebral artery (MCA) occlusion. Two groups of eight animals each were compared. The investigational group was injected intravenously with 1×10(7) cells/kg in serum-free culture medium (vehicle) 24 h after stroke onset, and the control group was treated with vehicle only at the same time poststroke. Intravenous administration of hUTC significantly improved neurological functional recovery without reducing infarct volume compared to vehicle-treated aged rats. Additionally, hUTC treatment significantly enhanced synaptogenesis and vessel density in the ischemic boundary zone (IBZ). Moreover, hUTC treatment resulted in a trend toward increased progenitor cell proliferation in the subventricular zone (SVZ) compared to vehicle-treated aged rats. Intravenous administration of hUTC improved functional recovery in aged rats after stroke. The enhancement of synaptogenesis and vessel density may contribute to the beneficial effects of hUTC in the treatment of stroke in the aged animal.

IFN-γ Stimulated Human Umbilical-Tissue-Derived Cells Potently Suppress NK Activation and Resist NK-Mediated Cytotoxicity In Vitro

Umbilical cord tissue represents a unique source of cells with potential for cell therapy applications for multiple diseases. Human umbilical tissue-derived cells (hUTC) are a developmentally early stage, homogenous population of cells that are HLA-ABC dim, HLA-DR negative, and lack expression of co-stimulatory molecules in the unactivated state. The lack of HLA-DR and co-stimulatory molecule expression on unactivated hUTC may account for their reduced immunogenicity, facilitating their use in allogeneic settings. However, such approaches could be confounded by host innate cells such as natural killer (NK) cells. Here, we evaluate in vitro NK cell interactions with hUTC and compare them with human mesenchymal stem cells (MSC). Our investigations show that hUTC suppress NK activation, through prostaglandin-E2 secretion in a contact-independent manner. Prestimulation of hUTC or human MSC with interferon gamma (IFN-γ) induced expression of the tryptophan degrading enzyme indoleamine 2, 3 dioxygenase, facilitating enhanced suppression. However, resting NK cells of different killer immunoglobulin-like receptor haplotypes did not kill hUTC or MSC; only activated NK cells had the ability to kill nonstimulated hUTC and, to a lesser extent, MSC. The cell killing process involved signaling through the NKG2D receptor and the perforin/granzyme pathway; this was supported by CD54 (ICAM-1) expression by hUTC. IFN-γ-stimulated hUTC or hMSC were less susceptible to NK killing; in this case, protection was associated with elevated HLA-ABC expression. These data delineate the different mechanisms in a two-way interaction between NK cells and two distinct cell therapies, hUTC or hMSC, and how these interactions may influence their clinical applications.

Recovery of fine motor performance after ischemic damage to motor cortex is facilitated by cell therapy in the rhesus monkey

We investigated the efficacy on recovery of function following controlled cortical ischemia in the monkey of the investigational cell drug product, CNTO 0007. This drug contains a cellular component, human umbilical tissue-derived cells, in a proprietary thaw and inject formulation. Results demonstrate significantly better recovery of motor function in the treatment group with no difference between groups in the volume or surface area of ischemic damage, suggesting that the cells stimulated plasticity.