Infusion of human umbilical cord blood cells protect against cerebral ischemia and damage during heatstroke in the rat

Attenuation of Heat-Induced Hypothalamic Ischemia, Inflammation, and Damage by Hyperbaric Oxygen in Rats

The present study was attempted to assess the mechanisms underlying the beneficial effects of hyperbaric oxygen (HBO₂; 100% O₂ at 253 kpa) in treating experimental heatstroke. Anesthetized rats were divided into five major groups: normothermic control (NC) rats treated with normobaric air (NBA; 21% O₂ at 101 kpa; NC + NBA); NC rats treated with HBO₂ (NC + HBO₂); heatstroke (HS) rats treated with NBA (HS + NBA); HS rats treated with hyperbaric air (HBA; 21% at 253 kpa; HS + HBA); and HS rats treated with HBO₂ (HS + HBO₂). HS groups were exposed to heat (43°C) for exactly 68 min and then allowed to recover at 26°C. HBA or HBO₂ was adopted 68 or 78 min after the start of heat exposure. Survival time values for (HS + NBA) rats, (HS + HBA) rats at 68 min, (HS + HBA) rats at 78 min, (HS + HBO₂) rats at 68 min, and (HS + HBO₂) rats at 78 min were found to be 90 ± 3, 133 ± 12, 109 ± 9, 240 ± 18, and 170 ± 15 min, respectively. Resuscitation with HBA or HBO₂ at 68 min was superior to those treated at 78 min in prolonging the survival time values. All (HS + NBA) animals displayed hyperthermia, hypotension, and increased cellular levels of ischemia, oxidative stress and damage markers, pro-inflammatory cytokines, and an indicator of polymorphonuclear cell accumulation in their hypothalamus as compared to those of NCs. Heat-induced hyperthermia was not affected by HBA or HBO₂ treatment. However, heat-induced hypotension and hypothalamic ischemia, oxidative stress, neuronal damage, and inflammation were all significantly reduced by HBA or HBO₂ therapy. Compared to those of HBA therapy, HBO₂ therapy had a significantly higher beneficial effect in treating heatstroke. Our results suggested that HBO₂ improved heatstroke outcomes, in part, by restoring normal hypothalamic function. Delaying the onset of HBO₂ therapy reduced the therapeutic efficiency.

Targeted Metabolomic Profiling Reveals Association Between Altered Amino Acids and Poor Functional Recovery After Stroke

Amino acids have been shown to be among the most important metabolites to be altered following stroke; however, they are a double-edged sword with regard to regulating hemostasis. In this study, we conducted a targeted metabolomic study to examine the association between serum levels of amino acids and functional recovery after stroke. Three hundred and fifty-one patients with stroke admitted to an acute rehabilitation hospital were screened, and 106 patients were selected based on inclusion and exclusion criteria. Recruited patients were stratified using Montebello Rehabilitation Factor Score (MRFS) efficiency. We selected the top (n = 20, 19%) and bottom (n = 20, 19%) of MRFS efficiency for metabolomic analysis. A total of 21 serum amino acids levels were measured using ultra high performance liquid chromatography and mass spectrometry. The normalized data were analyzed by multivariate approaches, and the selected potential biomarkers were combined in different combinations for prediction of stroke functional recovery. The results demonstrated that there were significant differences in leucine-isoleucine, proline, threonine, glutamic acid, and arginine levels between good and poor recovery groups. In the training (0.952) and test (0.835) sets, metabolite biomarker panels composed of proline, glutamic acid, and arginine had the highest sensitivity and specificity in distinguishing good recovery from poor. In particular, arginine was present in the top 10 combinations of the average area under the receiver operating characteristic curve (AUC) test set. Our findings suggest that amino acids related to energy metabolism and excitotoxicity may play an important role in functional recovery after stroke. Therefore, the level of serum arginine has predictive value for the recovery rate after stroke.

CD34- human placenta-derived mesenchymal stem cells protect against heat stroke mortality in rats

CD34 is a transmembrane phosphoglycoprotein used to selectively enrich bone marrow in hematopoietic stem cells for transplantation. Treating rats with CD34⁺ cells derived from human umbilical cord blood before or after heat stroke has been shown to promote survival. We investigated whether CD34^– human placenta-derived stem cells (PDMSCs) could improve survival following heat stroke in rats. Rats were subjected to heat stress (42°C for 98 min) to induce heat stroke. Intravenous administration of PDMSCs 1 day before or immediately after the onset of heat stroke improved survival by 60% and 20%, respectively. Pre-treatment with CD34⁻ PDMSCs protected against heat stroke injury more effectively than that treatment after injury. PDMSCs treatment attenuated cerebrovascular dysfunction, the inflammatory response, and lipid peroxidation. These data suggest human PDMSCs protect against heat stroke injury in rats. Moreover, these effects do not require the presence of CD34⁺ cells.

Mesenchymal stem cell-based treatments for stroke, neural trauma, and heat stroke

BACKGROUND

Mesenchymal stem cell (MSC) transplantation has been reported to improve neurological function following neural injury. Many physiological and molecular mechanisms involving MSC therapy-related neuroprotection have been identified.

METHODS

A review is presented of articles that pertain to MSC therapy and diverse brain injuries including stroke, neural trauma, and heat stroke, which were identified using an electronic search (e.g., PubMed), emphasize mechanisms of MSC therapy-related neuroprotection. We aim to discuss neuroprotective mechanisms that underlie the beneficial effects of MSCs in treating stroke, neural trauma, and heatstroke.

RESULTS

MSC therapy is promising as a means of augmenting brain repair. Cell incorporation into the injured tissue is not a prerequisite for the beneficial effects exerted by MSCs. Paracrine signaling is believed to be the most important mediator of MSC therapy in brain injury. The multiple mechanisms of action of MSCs include enhanced angiogenesis and neurogenesis, immunomodulation, and anti-inflammatory effects. Microglia are the first source of the inflammatory cascade during brain injury. Cytokines, including tumor necrosis factor-α, interleukin-1β, and interleukin-6, are significantly produced by microglia in the brain after experimental brain injury. The proinflammatory M1 phenotype of microglia is associated with tissue destruction, whereas the anti-inflammatory M2 phenotype of microglia facilitates repair and regeneration. MSC therapy may improve outcomes of ischemic stroke, neural trauma, and heatstroke by inhibiting the activity of M1 phenotype of microglia but augmenting the activity of M2 phenotype of microglia.

CONCLUSION

This review offers a testable platform for targeting microglial-mediated cytokines in clinical trials based upon the rational design of MSC therapy in the future. MSCs that are derived from the placenta provide a great choice for stem cell therapy. Although targeting the microglial activation is an important approach to reduce the burden of the injury, it is not the only one. This review focuses on this specific aspect.

Neurotherapeutic effect of cord blood derived CD45+ hematopoietic cells in mice after traumatic brain injury

Treatment of traumatic brain injury (TBI) is still an unmet need. Cell therapy by human umbilical cord blood (HUCB) has shown promising results in animal models of TBI and is under evaluation in clinical trials. HUCB contains different cell populations but to date, only mesenchymal stem cells have been evaluated for therapy of TBI. Here we present the neurotherapeutic effect, as evaluated by neurological score, using a single dose of HUCB-derived mononuclear cells (MNCs) upon intravenous (IV) administration one day post-trauma in a mouse model of closed head injury (CHI). Delayed (eight days post-trauma) intracerebroventricular administration of MNCs showed improved neurobehavioral deficits thereby extending the therapeutic window for treating TBI. Further, we demonstrated for the first time that HUCB-derived pan-hematopoietic CD45 positive (CD45(+)) cells, isolated by magnetic sorting and characterized by expression of CD45 and CD11b markers (96-99%), improved the neurobehavioral deficits upon IV administration, which persisted for 35 days. The therapeutic effect was in a direct correlation to a reduction in the lesion volume and decreased by pre-treatment of the cells with anti-human-CD45 antibody. At the site of brain injury, 1.5-2 h after transplantation, HUCB-derived cells were identified by near infrared scanning and immunohistochemistry using anti-human-CD45 and anti-human-nuclei antibodies. Nerve growth factor and vascular endothelial growth factor levels were differentially expressed in both ipsilateral and contralateral brain hemispheres, thirty-five days after CHI, measured by enzyme-linked immunosorbent assay. These findings indicate the neurotherapeutic potential of HUCB-derived CD45(+) cell population in a mouse model of TBI and propose their use in the clinical setting of human TBI.

Stem Cell Banking for Regenerative and Personalized Medicine

Regenerative medicine, tissue engineering and gene therapy offer the opportunity to treat and cure many of today’s intractable afflictions. These approaches to personalized medicine often utilize stem cells to accomplish these goals. However, stem cells can be negatively affected by donor variables such as age and health status at the time of collection, compromising their efficacy. Stem cell banking offers the opportunity to cryogenically preserve stem cells at their most potent state for later use in these applications. Practical stem cell sources include bone marrow, umbilical cord blood and tissue, and adipose tissue. Each of these sources contains stem cells that can be obtained from most individuals, without too much difficulty and in an economical fashion. This review will discuss the advantages and disadvantages of each stem cell source, factors to be considered when contemplating banking each stem cell source, the methodology required to bank each stem cell source, and finally, current and future clinical uses of each stem cell source.

Humoral activity of cord blood-derived stem/progenitor cells: implications for stem cell-based adjuvant therapy of neurodegenerative disorders

Background

Stem/progenitor cells (SPCs) demonstrate neuro-regenerative potential that is dependent upon their humoral activity by producing various trophic factors regulating cell migration, growth, and differentiation. Herein, we compared the expression of neurotrophins (NTs) and their receptors in specific umbilical cord blood (UCB) SPC populations, including lineage-negative, CD34⁺, and CD133⁺ cells, with that in unsorted, nucleated cells (NCs).

Methods and Results

The expression of NTs and their receptors was detected by QRT-PCR, western blotting, and immunofluorescent staining in UCB-derived SPC populations (i.e., NCs vs. lineage-negative, CD34⁺, and CD133⁺ cells). To better characterize, global gene expression profiles of SPCs were determined using genome-wide RNA microarray technology. Furthermore, the intracellular production of crucial neuro-regenerative NTs (i.e., BDNF and NT-3) was assessed in NCs and lineage-negative cells after incubation for 24, 48, and 72 h in both serum and serum-free conditions. We discovered significantly higher expression of NTs and NT receptors at both the mRNA and protein level in lineage-negative, CD34⁺, and CD133⁺ cells than in NCs. Global gene expression analysis revealed considerably higher expression of genes associated with the production and secretion of proteins, migration, proliferation, and differentiation in lineage-negative cells than in CD34⁺ or CD133⁺ cell populations. Notably, after short-term incubation under serum-free conditions, lineage-negative cells and NCs produced significantly higher amounts of BDNF and NT-3 than under steady-state conditions. Finally, conditioned medium (CM) from lineage-negative SPCs exerted a beneficial impact on neural cell survival and proliferation.

Conclusions

Collectively, our findings demonstrate that UCB-derived SPCs highly express NTs and their relevant receptors under steady-state conditions, NT expression is greater under stress-related conditions and that CM from SPCs favorable influence neural cell proliferation and survival. Understanding the mechanisms governing the characterization and humoral activity of subsets of SPCs may yield new therapeutic strategies that might be more effective in treating neurodegenerative disorders.

Intrathecal Administration of Autologous CD34 Positive Cells in Patients with Past Cerebral Infarction: A Safety Study

Regenerative strategies in treatment of stroke have great potential. The goal of the current study was to investigate safety of intrathecal administration of autologous CD34 positive cells in treatment of patients with poststroke. A total of eight male patients with a history of stroke were enrolled. The patients were treated subcutaneously with 5 μg/kg body weight rhG-CSF for 5 consecutive days, and then leukapheresis was performed to concentrate cells for CD34 positive immunoselection. All patients underwent intrathecal administration of CD34 positive cells via lumbar puncture. The primary outcome was safety evaluation for 12-month followup. In addition, behavioral function was evaluated with NIH stroke scale and Barthel index 1, 6, and 12 months after the last treatment, respectively. There were no major adverse events, and abnormal changes of blood tests during the whole treatment process included intrathecal administration and 12-month followup. The main message from the current study was that administration of G-CSF-mobilized autologous CD34 positive cells in patients with poststroke was safe. Future studies with larger population and control group are needed to confirm the safety and investigate the efficacy.

Stem cells as promising therapeutic options for neurological disorders

Due to the limitations of pharmacological and other current therapeutic strategies, stem cell therapies have emerged as promising options for treating many incurable neurologic diseases. A variety of stem cells including pluripotent stem cells (i.e., embryonic stem cells and induced pluripotent stem cells) and multipotent adult stem cells (i.e., fetal brain tissue, neural stem cells, and mesenchymal stem cells from various sources) have been explored as therapeutic options for treating many neurologic diseases, and it is becoming obvious that each type of stem cell has pros and cons as a source for cell therapy. Wise selection of stem cells with regard to the nature and status of neurologic dysfunctions is required to achieve optimal therapeutic efficacy. To this aim, the stem cell-mediated therapeutic efforts on four major neurological diseases, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and stroke, will be introduced, and current problems and future directions will be discussed.

Enhanced survival and neurite network formation of human umbilical cord blood neuronal progenitors in three-dimensional collagen constructs

Umbilical cord blood (CB) stem cells have been proposed for cell-based therapeutic applications for diverse diseases of the CNS. We hypothesized that tissue-engineering strategies may extend the efficacy of these approaches by improving the long-term viability and function of stem cell-derived neuronal progenitors. To test our hypothesis, we explored the survival and differentiation of human CB-derived neuronal progenitors (HUCBNP) in a three-dimensional (3D) collagen construct. In contrast to two-dimensional culture conditions, the cells survived in 3D for an extended period of time of more than 2 months. Under 3D conditions, HUCBNP underwent spontaneous neuronal differentiation, which was further enhanced by treatment with neuronal conditioned medium (CM) and nerve growth factor (NGF). Neurite outgrowth, quantified by assessing the fractal dimension (D f) of the complex neuronal networks, was significantly enhanced under 3D conditions in the presence of CM/NGF, concomitant with a reduced expression of the early neuronal marker nestin (1.9-fold), and increased levels of mature neuronal markers such as MAP-2 (3.6-fold), β-tubulin (1.5-fold), and neuronal specific enolase (6.6-fold) and the appearance of the synaptic marker synaptophysin. To assess the feasibility for clinical usage, HUCBNP were also isolated from frozen CB samples and cultured under 3D conditions. The data indicate the essential complete preservation of neurotrophic (survival) and neurotropic (neurite outgrowth) properties. In conclusion, 3D culture conditions are proposed as an essential step for both maintenance of CB neuronal progenitors in vitro and for investigating specific features of neuronal differentiation towards future use in regenerative therapy.

Combination treatment of stroke with sub-therapeutic doses of Simvastatin and human umbilical cord blood cells enhances vascular remodeling and improves functional outcome

Human umbilical cord blood cells (HUCBCs) have been employed as a restorative treatment for experimental stroke. In this study, we investigated whether transplantation of sub-therapeutic doses of HUCBCs and Simvastatin enhances cerebral vascular remodeling after stroke. Adult male Wistar rats (n=34) were subjected to transient middle cerebral artery occlusion (MCAo) and treated with: phosphate-buffered solution (PBS, gavaged daily for 7 days); Simvastatin (0.5mg/kg, gavaged daily for 7 days); HUCBCs (1×10(6), injected once via tail vein); and combination Simvasatin with HUCBCs, starting at 24h after MCAo. There was no significant difference between Simvastatin- or HUCBC-monotherapy and MCAo-alone group. Combination treatment 24h post-stroke significantly increased the perimeter of von Willebrand factor (vWF)-positive vessels, the diameter and density of alpha smooth muscle actin (αSMA)-positive arteries, and the percentage of 5-bromodeoxyuridine (BrdU)-positive endothelial cells (ECs) in the ischemic boundary zone (IBZ) compared with MCAo-alone or HUCBC-monotherapy 14 days after MCAo (p<0.05, n=8/group); Combination treatment significantly increased the densities of vWF-vessels and αSMA-arteries as well as the densities of BrdU-ECs and BrdU-positive smooth muscle cells (SMCs) in vascular walls in the IBZ compared with Simvastatin-monotherapy. Moreover, the increased BrdU-ECs and BrdU-SMCs were significantly correlated with neurological functional outcome 14 days after MCAo. Combination treatment also significantly increased the expression of Angiopoietin-1 (Ang1), Tie2 and Occludin in the IBZ (p<0.05, n=8/group). The in vitro experiments showed that combination treatment and Ang1 significantly increased capillary-like tube formation and arterial cell migration; anti-Ang1 significantly reduced combination treatment-induced tube-formation and artery cell migration (p<0.05, n=6/group). These findings indicated that a combination of sub-therapeutic doses of Simvastatin and HUCBCs treatment of stroke increases Ang1/Tie2 and Occludin expression in the ischemic brain, amplifies endogenous angiogenesis and arteriogenesis, and enhances vascular remodeling which in concert may contribute to functional outcome after stroke.

Stem cell therapy for cerebral ischemia: from basic science to clinical applications

Recent stem cell technology provides a strong therapeutic potential not only for acute ischemic stroke but also for chronic progressive neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis with neuroregenerative neural cell replenishment and replacement. In addition to resident neural stem cell activation in the brain by neurotrophic factors, bone marrow stem cells (BMSCs) can be mobilized by granulocyte-colony stimulating factor for homing into the brain for both neurorepair and neuroregeneration in acute stroke and neurodegenerative diseases in both basic science and clinical settings. Exogenous stem cell transplantation is also emerging into a clinical scene from bench side experiments. Early clinical trials of intravenous transplantation of autologous BMSCs are showing safe and effective results in stroke patients. Further basic sciences of stem cell therapy on a neurovascular unit and neuroregeneration, and further clinical advancements on scaffold technology for supporting stem cells and stem cell tracking technology such as magnetic resonance imaging, single photon emission tomography or optical imaging with near-infrared could allow stem cell therapy to be applied in daily clinical applications in the near future.

The splenic response to ischemic stroke: what have we learned from rodent models?

The majority of promising experimental compounds have failed in clinical trials, highlighting the need for novel approaches to treat stroke. Much research has been devoted to elucidating the signaling pathways involved in delayed neuroinflammation that can be targeted at clinically relevant time points. The field of stroke research has benefited from experiments characterizing the temporal expression profiles of candidate cytokines, chemokines, matrix metalloproteinases, and other putative pro-inflammatory molecules. Yet, these data have offered only a glimpse into the complex pathological sequelae and have not advanced the treatment of neuropathies. Upon recognition that peripheral immune cell activation is involved in penumbral expansion, the spleen has emerged as a novel target that mediates the peripheral immune response and promotes pro-inflammatory injury. Although the precise mechanisms have yet to be elucidated, accumulated evidence demonstrates that focal cerebral ischemia alters cytokine, chemokine, and immune cell profiles in the spleen. Additionally, removal of this peripheral lymphoid organ is neuroprotective, and the efficacy of several protective therapies has been linked to actions at the level of the spleen. Future experiments aimed at identifying the splenic lymphocyte populations that respond to ischemic stroke, as well as their signaling mechanisms, are critical in developing novel therapies.

Kynurenic acid attenuates multiorgan dysfunction in rats after heatstroke

AIM

To assess whether systemic delivery of kynurenic acid improves the outcomes of heatstroke in rats.

METHODS

Anesthetized rats were divided into 2 major groups and given vehicle solution (isotonic saline 0.3 mL/kg rat weight) or kynurenic acid (30-100 mg in 0.3 mL saline/kg) 4 h before the start of thermal experiments. They were exposed to an ambient temperature of 43 °C for 68 min to induce heatstroke. Another group of rats were exposed to room temperature (26 °C) and used as normothermic controls. Their core temperatures, mean arterial pressures, serum levels of systemic inflammatory response molecules, hypothalamic values of apoptotic cells and neuronal damage scores, and spleen, liver, kidney and lung values of apoptotic cells were determined.

RESULTS

The survival time values during heatstroke for vehicle-treated rats were decreased from the control values of 475-485 min to new values of 83-95 min. Treatment with KYNA (30-100 mg/kg, iv) 4 h before the start of heat stress significantly and dose-dependently decreased the survival time to new values of 152-356 min (P<0.05). Vehicle-treated heatstroke rats displayed hypotension, hypothalamic neuronal degeneration and apoptosis, increased serum levels of tumor necrosis factor-α (TNF-α), intercellular adhesion molecule-1 (ICAM-1), and interleukin-10 (IL-10), and spleen, liver, kidney, and lung apoptosis. KYNA preconditioning protected against hypotension but not hyperthermia and attenuated hypothalamic neuronal degeneration and apoptosis during heatstroke. KYNA preconditioning attenuated spleen, kidney, liver, and lung apoptosis and up-regulated serum IL-10 levels but down-regulated serum TNF-α and ICAM-1 levels during heatstroke.

CONCLUSION

Our results suggest that systemic delivery of kynurenic acid may attenuate multiorgan dysfunction in rats after heatstroke.

Tissue regeneration potential in human umbilical cord blood

Regenerative medicine is the process of creating functional tissue with the aid of stem cells, to repair loss of organ function. Possible targets for regenerative medicine include orthopaedic, cardiac, hepatic, pancreatic and central nervous system (CNS) applications. Umbilical cord blood (CB) has established itself as a legitimate source for haematopoietic stem cell transplantation. It is also considered an accessible and less immunogenic source for mesenchymal, unrestricted somatic and for other stem cells with pluri/multipotent properties. The latter are capable of differentiating into a wide variety of cell types including bone, cartilage, cardiomyocytes and neural. They also possess protective abilities that may contribute to tissue repair even if in vitro differentiation is excluded. In view of the absence of treatment for many devastating diseases, the elucidation of non-haematopoietic applications for CB will facilitate the development of pioneering relevant cell therapy approaches. This review focusses on current studies using human CB-derived cells for regenerative medicine.

The therapeutic potential of human umbilical cord blood-derived mesenchymal stem cells in Alzheimer's disease

The neuropathological hallmarks of Alzheimer's disease (AD) include the presence of extracellular amyloid-beta peptide (Abeta) in the form of amyloid plaques in the brain parenchyma and neuronal loss. The mechanism associated with neuronal death by amyloid plaques is unclear but oxidative stress and glial activation has been implicated. Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) are being scrutinized as a potential therapeutic tool to prevent various neurodegenerative diseases including AD. However, the therapeutic impact of hUCB-MSCs in AD has not yet been reported. Here we undertook in vitro work to examine the potential impact of hUCB-MSCs treatment on neuronal loss using a paradigm of cultured hippocampal neurons treated with Abeta. We confirmed that hUCB-MSCs co-culture reduced the hippocampal apoptosis induced by Abeta treatment. Moreover, in an acute AD mouse model to directly test the efficacy of hUCB-MSCs treatment on AD-related cognitive and neuropathological outcomes, we demonstrated that markers of glial activation, oxidative stress and apoptosis levels were decreased in AD mouse brain. Interestingly, hUCB-MSCs treated AD mice demonstrated cognitive rescue with restoration of learning/memory function. These data suggest that hUCB-MSCs warrant further investigation as a potential therapeutic agent in AD.

Human umbilical cord blood-derived mesenchymal stem cells improve neuropathology and cognitive impairment in an Alzheimer's disease mouse model through modulation of neuroinflammation

Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSC) have a potential therapeutic role in the treatment of neurological disorders, but their current clinical usage and mechanism of action has yet to be ascertained in Alzheimer's disease (AD). Here we report that hUCB-MSC transplantation into amyloid precursor protein (APP) and presenilin1 (PS1) double-transgenic mice significantly improved spatial learning and memory decline. Furthermore, amyloid-β peptide (Aβ) deposition, β-secretase 1 (BACE-1) levels, and tau hyperphosphorylation were dramatically reduced in hUCB-MSC transplanted APP/PS1 mice. Interestingly, these effects were associated with reversal of disease-associated microglial neuroinflammation, as evidenced by decreased microglia-induced proinflammatory cytokines, elevated alternatively activated microglia, and increased anti-inflammatory cytokines. These findings lead us to suggest that hUCB-MSC produced their sustained neuroprotective effect by inducing a feed-forward loop involving alternative activation of microglial neuroinflammation, thereby ameliorating disease pathophysiology and reversing the cognitive decline associated with Aβ deposition in AD mice.

Non-haematological uses of cord blood stem cells

Embryonic stem (ES) cell therapies are often promoted as the optimal stem cell source for regenerative medicine applications because of their ability to develop into any tissue in the body. Unfortunately, ES cell applications are currently limited by ethical, political, biological and regulatory hurdles. However, multipotent non-ES cells are available in large numbers in umbilical cord blood (CB). CB stem cells are capable of giving rise to hematopoietic, epithelial, endothelial and neural tissues both in vitro and in vivo. Thus, CB stem cells are amenable to treat a wide variety of diseases including cardiovascular, ophthalmic, orthopaedic, neurological and endocrine diseases. In addition, the recent use of CB in several regenerative medicine clinical studies has demonstrated its pluripotent nature. Here we review the latest developments in the use of CB in regenerative medicine. Examples of these usages include cerebral palsy and type I diabetes. The numbers of individuals affected with each of these diseases are estimated at 10 000 infants diagnosed with cerebral palsy annually and 15 000 youths diagnosed with type 1 diabetes annually. A summary of the initial results from such clinical studies using autologous cord blood stem cells will be presented.

Human umbilical cord blood cells protect against hypothalamic apoptosis and systemic inflammation response during heatstroke in rats

BACKGROUND

Intravenous administration of human umbilical cord blood cells (HUCBC) has been shown to improve heatstroke by reducing arterial hypotension as well as cerebral ischemia and damage in a rat model. To extend these findings, we assessed both hypothalamic neuronal apoptosis and systemic inflammatory responses in the presence of HUCBCs or vehicle medium immediately after initiation of heatstroke.

METHODS

Anesthetized rats, immediately after the initiation of heat stress, were divided into two groups and given either serum-free lymphocyte medium (0.3mL per rat, intravenously) or HUCBCs (5 x 10(6) in 0.3 mL serum-free lymphocyte medium, intravenously). Another group of rats were exposed to room temperature (26 degrees C) and used as normothermic controls. Heatstroke was induced by exposing the anesthetized rats to a high ambient temperature of 43 degrees C for 68 minutes.

RESULTS

After the onset of heatstroke, animals treated with serum-free lymphocyte medium displayed hyperthermia, hypotension, bradycardia, hypothalamic neuronal apoptosis and degeneration, and up-regulation of systemic inflammatory response molecules including serum tumor necrosis factor-alpha, soluble intercellular adhesion molecule-1 and E-selectin. Heatstroke-induced hypotension, bradycardia, hypothalamic neuronal apoptosis and degeneration, and increased systemic inflammatory response molecules were significantly inhibited by HUCBC treatment. Although heatstroke-induced hyperthermia was not affected by HUCBC treatment, the serum levels of the anti-inflammatory cytokine interleukin-10 were significantly increased by HUCBC therapy during hyperthermia.

CONCLUSIONS

These findings suggest that HUCBC transplantation may prevent the occurrence of heatstroke by reducing hypothalamic neuronal damage and the systemic inflammatory responses.

Human Umbilical Cord Blood Cell Grafts for Brain Ischemia

Irreversible and permanent damage develop immediately adjacent to the region of reduced cerebral blood perfusion in stroke patients. Currently, the proven thrombolytic treatment for stroke, tissue plasminogen activator, is only effective when administered within 3 h after stroke. These disease characteristics should be taken under consideration in developing any therapeutic intervention designed to widen the narrow therapeutic range, especially cell-based therapy. Over the past several years, our group and others have characterized the therapeutic potential of human umbilical cord blood cells for stroke and other neurological disorders using in vitro and vivo models focusing on the cells' ability to differentiate into nonhematopoietic cells including neural lineage, as well as their ability to produce several neurotrophic factors and modulate immune and inflammatory reaction. Rather than the conventional cell replacement mechanism, we advance alternative pathways of graft-mediated brain repair involving neurotrophic effects resulting from release of various growth factors that afford cell survival, angiogenesis, and anti-inflammation. Eventually, these multiple protective and restorative effects from umbilical cord blood cell grafts may be interdependent and act in harmony in promoting therapeutic benefits for stroke.

Human umbilical cord blood stem cells, myocardial infarction and stroke

Myocardial infarction (MI) and stroke are the first and third leading causes of death in the U.S.A. accounting for more than 1 in 3 deaths per annum. Despite interventional and pharmaceutical advances, the number of people diagnosed with heart disease is on the rise. Therefore, new clinical strategies are needed. Cell-based therapy holds great promise for treatment of these diseases and is currently under extensive preclinical as well as clinical trials. The source and types of stem cells for these clinical applications are questions of great interest. Human umbilical cord blood (hUCB) appears to be a logical candidate as a source of cells. hUCB is readily available, and presents little ethical challenges. Stem cells derived from hUCB are multipotent and immunologically naive. Here is a critical literature review of the beneficial effects of hUCB cell therapy in preclinical trials.

Systemic neurotransplantation--a problem-oriented systematic review

Systemic neurotransplantation (SNT) was introduced in the laboratory in 2000 and currently it is being widely examined in animal models of neurological disorders. The aim of this systematic review was to evaluate the current state of knowledge in the field of experimental SNT and the premise for the introduction of clinical trials. PubMed was searched and 60 articles utilizing an SNT approach were found and subjected to analysis. The time window for cell transplantation was addressed in only two studies, with contradictory results. Immunosuppression was applied in 25% of studies. No study addressed the justification for immunosuppression. Bone marrow was the most frequent source of grafted cells, followed by cord blood and then by cells of embryonic origin. Studies investigating dose-dependency revealed no satisfactory results with transplantation of less than 10(6) cells/animal; the efficient dose most frequently ranged from 10(6)-10(7) cells/animal (mice and rats). The behavioral effects of cell transplantation were assessed in 75% of all studies; significant improvement was achieved in 95% of them. Morphological effect was evaluated in half of the studies; significant positive effect was achieved in 73% of them. Experimental attempts to elucidate the mechanisms mediating cell-dependent effect were not undertaken in half of the studies. In the other half, the most frequent mechanisms were growth factors, neurogenesis and immunomodulation. SNT still seems to be at the very initial stage of development. Many critical factors have not been sufficiently addressed in laboratory studies and they must be clarified before the introduction of clinical trials.

Interferon-gamma-induced neuronal differentiation of human umbilical cord blood-derived progenitors

Human umbilical cord blood (HUCB) provides a source of progenitors for cell therapy. We isolated and characterized an HUCB-derived population of progenitors (HUCBNP), differentiated toward neuronal phenotype by human neuroblastoma-conditioning medium (CM) and nerve growth factor (NGF), which have been found to confer neuroprotection toward hypoxia-mediated neuronal injury. This study investigated whether interferon-gamma (IFN-gamma) contributes to HUCBNP differentiation. IFN-gamma was detected in the CM used for the induction of differentiation of HUCBNP and a neutralizing antibody of IFN-gamma significantly inhibited either IFN-gamma or CM-induced differentiation. Transcriptome analysis of CM-differentiated HUCBNP, identified 86 genes as highly upregulated, among them 25 were IFN-induced (such as 2',5'-oligoadenylate synthetase 1 and 2, IFN-induced protein and transmembrane proteins, STAT1 (IFN-gamma-receptor signal transducer and activator of transcription) and chemokine C-X-C motif ligand 5). Treatment of HUCBNP with human recombinant IFN-gamma, inhibited cell proliferation in a dose-dependent manner. IFN-gamma (1-100 ng/ml) enhanced neuronal differentiation, expressed by neurite outgrowths and increased expression of the neuronal markers beta-tubulin III, microtubule-associated protein 2, neuronal nuclei, neurofilament M and neuronal-specific enolase. IFN-gamma additively cooperated with NGF to induce the differentiation of HUCBNP. These data indicate that IFN-gamma promotes neuronal differentiation of HUCB-derived progenitors, proposing its use in future protocols towards cell therapy.

Cord blood cell therapy alters LV remodeling and cytokine expression but does not improve heart function after myocardial infarction in rats

OBJECTIVE

In this study the ability of unrestricted somatic stem cells (USSC) and mononuclear cord blood cells (MN-CBC) was tested to improve heart function and left ventricular (LV) remodeling after myocardial infarction (MI).

METHODS

The cells were delivered by i.v. or intramyocardial injections in rat models of MI by permanent coronary artery occlusion and by ischemia/reperfusion (I/R) injury. Heart function and remodeling was followed by recurrent echocardiography over 8 or 12 weeks after which catheterization was performed.

RESULTS

Although injected labeled cells could be observed within the myocardium for up to 6 d, there was no sign of cardiac regeneration 8 or 12 weeks after MI. However, the mRNA expression of components of the extracellular matrix was attenuated in the infarct scar 12 weeks after MI and cell injection. Additionally, the expression of interleukin (IL)-6 but not of IL-1 beta increased at the site of injury and the adjacent border-zone 12 weeks after I/R and USSC-injection. However, these effects did not translate into improved heart function or attenuated LV dilatation.

CONCLUSION

These data indicate that cord blood cell implantation after MI acts through paracrine mechanisms to modify remodeling rather than myocyte regeneration. The role of myofibroblasts and the optimal conditions of cell application need to be determined to translate these mechanisms into functional improvement.

Evidence for neuroprotective properties of human umbilical cord blood cells after neuronal hypoxia in vitro

Background

One of the most promising options for treatment of stroke using adult stem cells are human umbilical cord blood (HUCB) cells that were already approved for therapeutic efficacy in vivo. However, complexity of animal models has thus far limited the understanding of beneficial cellular mechanisms. To address the influence of HUCB cells on neuronal tissue after stroke we established and employed a human in vitro model of neuronal hypoxia using fully differentiated vulnerable SH-SY5Y cells. These cells were incubated under an oxygen-reduced atmosphere (O₂< 1%) for 48 hours. Subsequently, HUCB mononuclear cells (MNC) were added to post-hypoxic neuronal cultures. These cultures were characterized regarding to the development of apoptosis and necrosis over three days. Based on this we investigated the therapeutic influence of HUCB MNC on the progression of apoptotic cell death. The impact of HUCB cells and hypoxia on secretion of neuroprotective and inflammatory cytokines, chemokines and expression of adhesion molecules was proved.

Results

Hypoxic cultivation of neurons initially induced a rate of 26% ± 13% of apoptosis. Hypoxia also caused an enhanced expression of Caspase-3 and cleaved poly(ADP-ribose) polymerase (PARP). Necrosis was only detected in low amounts. Within the next three days rate of apoptosis in untreated hypoxic cultures cumulated to 85% ± 11% (p ≤ 0.001). Specific cytokine (VEGF) patterns also suggest anti-apoptotic strategies of neuronal cells. Remarkably, the administration of MNC showed a noticeable reduction of apoptosis rates to levels of normoxic control cultures (7% ± 3%; p ≤ 0.001). In parallel, clustering of administered MNC next to axons and somata of neuronal cells was observed. Furthermore, MNC caused a pronounced increase of chemokines (CCL5; CCL3 and CXCL10).

Conclusion

We established an in vitro model of neuronal hypoxia that affords the possibility to investigate both, apoptotic neuronal cell death and neuroprotective therapies. Here we employed the therapeutic model to study neuroprotective properties of HUCB cells.

We hypothesize that the neuroprotective effect of MNC was due to anti-apoptotic mechanisms related to direct cell-cell contacts with injured neuronal cells and distinct changes in neuroprotective, inflammatory cytokines as well as to the upregulation of chemokines within the co-cultures.

Human umbilical cord blood-derived CD34+ cells can be used as a prophylactic agent for experimental heatstroke

We attempted to assess the prophylactic effect of human umbilical cord blood-derived CD34(+) cells in experimental heatstroke. Anesthetized rats, 1 day before heat stress, were divided into 2 major groups and given CD34(-) cells (defined by 1 x 10(6) human cord blood lymphocytes and monocytes that contained <0.2% CD34(+) cells) or CD34(+) cells (defined by 1 x 10(6) human cord blood lymphocytes and monocytes that contained >95% CD34(+) cells). They were exposed to ambient temperature of 43 degrees C for 70 min to induce heatstroke. When the CD34(-) cells-treated or untreated rats underwent heat stress, their survival time values were found to be 20-24 min. Pretreatment with CD34(+) cells significantly increased survival time (123-351 min). As compared with normothermic controls, all CD34(-) cells-treated heatstroke animals displayed hypotension, hepatic and renal failure, hypercoagulable state, activated inflammation, and cerebral ischemia and injury. However, these heatstroke reactions all were significantly suppressed by CD34(+) cells pretreatment. In addition, the levels of interleukin-10 in plasma and glial cell line-derived neurotrophic factors in brain were all significantly increased after CD34(+) cell administration during heatstroke. Our data indicate that human umbilical cord-derived CD34(+) cells can be used as a prophylactic agent for experimental heatstroke.

The potential of umbilical cord blood multipotent stem cells for nonhematopoietic tissue and cell regeneration

Stem cells have been isolated from human embryos, fetal tissue, umbilical cord blood (UCB), and also from "adult" sources. Adult stem cells are found in many tissues of the body and are capable of maintaining, generating, and replacing terminally differentiated cells. A source of pluripotent stem cells has been recently identified in UCB that can also differentiate across tissue lineage boundaries into neural, cardiac, epithelial, hepatocytic, and dermal tissue. Thus, UCB may provide a future source of stem cells for tissue repair and regeneration. Its widespread availability makes UCB an attractive source for tissue regeneration. UCB-derived stem cells offer multiple advantages over adult stem cells, including their immaturity, which may play a significant role in reduced rejection after transplantation into a mismatched host and their ability to produce larger quantities of homogenous tissue or cells. While research with embryonic stem cells continues to generate considerable controversy, human umbilical stem cells provide an alternative cell source that has been more ethically acceptable and appears to have widespread public support. This review will summarize the in vitro and in vivo studies examining UCB stem cells and their potential use for therapeutic application for nonhematopoietic tissue and cell regeneration.

Human umbilical cord blood-derived CD34+ cells cause attenuation of multiorgan dysfunction during experimental heatstroke

Multiorgan dysfunction ensuing from severe heatstroke includes hypotension, hepatic and renal failure, hypercoagulable state, activated inflammation, and cerebral ischemia and injury. We attempted to assess whether human umbilical cord blood-derived CD34+ cell therapy improves survival during experimental heatstroke by attenuating multiorgan dysfunction. Anesthetized rats, immediately after the onset of heatstroke, were divided into 2 major groups and given CD34- or CD34+ cells (1 x 10(5)-5 x 10(5)/mL/kg body weight) i.v. They were exposed to ambient temperature of 43 degrees C to induce heatstroke. Another group of rats were exposed to room temperature (26 degrees C) and used as normothermic controls. Hypotension, hepatic and renal failure (evidenced by increased serum urea nitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase levels in plasma), hypercoagulable state (evidenced by increased prothrombin time, activated partial thromboplastin time, and D-dimer, and decreased platelet count and protein C in plasma), activated inflammation (evidence by increased TNF-alpha levels in serum), and cerebral dysfunction (evidenced by intracranial hypertension, cerebral hypoperfusion and hypoxia, and cerebral ischemia and injury) were monitored. When the CD34- cell-treated or untreated rats underwent heat stress, their survival time values were found to be 19 to 23 min. Resuscitation with CD34+ cells significantly improved survival time (duration, 63-291 min). As compared with normothermic controls, all CD34- cell-treated heatstroke animals displayed hypotension, hepatic and renal failure, hypercoagulable state, activated inflammation, and cerebral ischemia and injury. However, CD34+ cell therapy significantly caused attenuation of all the above-mentioned heatstroke reactions. In addition, the levels of IL-10 in plasma and glial cell line-derived neurotrophic factors in brain were all significantly increased after CD34+ cell therapy during heatstroke. Our data indicate that CD34+ cell therapy may resuscitate persons who had a heatstroke by reducing multiorgan dysfunction or failure.

Neural stem/precursor cells for the treatment of ischemic stroke

In ischemic stroke, the third most frequent cause of mortality in industrialized countries, therapeutic options have until now been limited to the first hours after disease onset. Cell transplantation has emerged in various neurological disorders, including experimental stroke, as a successful recovery-promoting approach also in the post-acute stroke phase. However, before envisaging any translation into humans of such promising cell-based approaches we still need to clarify: (i) the ideal cell source for transplantation, (ii) the most appropriate route of cell administration, and, last but not least, (iii) the best approach to achieve an appropriate and functional integration of transplanted cells into the host tissue. Here we discuss, with special emphasis on neural stem/precursor cells, potential mechanisms that may be involved in the action of cell-based therapies in stroke.

Stem cell therapy for autism

Autism spectrum disorders (ASD) are a group of neurodevelopmental conditions whose incidence is reaching epidemic proportions, afflicting approximately 1 in 166 children. Autistic disorder, or autism is the most common form of ASD. Although several neurophysiological alterations have been associated with autism, immune abnormalities and neural hypoperfusion appear to be broadly consistent. These appear to be causative since correlation of altered inflammatory responses, and hypoperfusion with symptology is reported. Mesenchymal stem cells (MSC) are in late phases of clinical development for treatment of graft versus host disease and Crohn's Disease, two conditions of immune dysregulation. Cord blood CD34+ cells are known to be potent angiogenic stimulators, having demonstrated positive effects in not only peripheral ischemia, but also in models of cerebral ischemia. Additionally, anecdotal clinical cases have reported responses in autistic children receiving cord blood CD34+ cells. We propose the combined use of MSC and cord blood CD34+cells may be useful in the treatment of autism.

Human umbilical cord blood cells or estrogen may be beneficial in treating heatstroke

This current review summarized animal models of heatstroke experimentation that promote our current knowledge of therapeutic effects on cerebrovascular dysfunction, coagulopathy, and/or systemic inflammation with human umbilical cord blood cells (HUCBCs) or estrogen in the setting of heatstroke. Accumulating evidences have demonstrated that HUCBCs provide a promising new therapeutic method against neurodegenerative diseases, such as stroke, traumatic brain injury, and spinal cord injury as well as blood disease. More recently, we have also demonstrated that post- or pretreatment by HUCBCs may resuscitate heatstroke rats with by reducing circulatory shock, and cerebral nitric oxide overload and ischemic injury. Moreover, CD34+ cells sorted from HUCBCs may improve survival by attenuating inflammatory, coagulopathy, and multiorgan dysfunction during experimental heatstroke. Many researchers indicated pro- (e.g. tumor necrosis factor-alpha [TNF-alpha]) and anti-inflammatory (e.g. interleukin-10 [IL-10]) cytokines in the peripheral blood stream correlate with severity of circulatory shock, cerebral ischemia and hypoxia, and neuronal damage occurring in heatstroke. It has been shown that intravenous administration of CD34+ cells can secrete therapeutic molecules, such as neurotrophic factors, and attenuate systemic inflammatory reactions by decreasing serum TNF-alpha but increasing IL-10 during heatstroke. Another line of evidence has suggested that estrogen influences the severity of injury associated with cerebrovascular shock. Recently, we also successfully demonstrated estrogen resuscitated heatstroke rats by ameliorating systemic inflammation. Conclusively, HUCBCs or estrogen may be employed as a beneficial therapeutic strategy in prevention and repair of cerebrovascular dysfunction, coagulopathy, and/or systemic inflammation during heatstroke.

Cord blood rescues stroke-induced changes in splenocyte phenotype and function

The neuroprotective mechanism of human umbilical cord blood cells (HUCBC) in the rat middle cerebral artery occlusion (MCAO) stroke model remains uncertain. Given the inflammatory sequelae that occur following stroke, we investigated whether HUCBC protection could be derived from the modulation of this immuno-inflammatory event, suggested by the attraction of the HUCBC to the spleen. We found that, following MCAO, rat spleen size was reduced concomitantly with their CD8+ T-cell counts. Interestingly, MCAO-induced spleen size reduction correlated with the extent of ischemic damage, however, HUCBC treatment rescued the spleen weight, splenic CD8+ T-cell counts, as well as the amount of brain injury. Additionally, splenocyte proliferation assays demonstrated that HUCBC treatment opposed MCAO-associated T-cell proliferation by increasing the production of IL-10 while decreasing IFN-gamma. Taken together, these results suggest a novel immunomodulatory mechanism by which HUCBC mediate protection in the rat MCAO model of stroke.

Cytokines produced by cultured human umbilical cord blood (HUCB) cells: Implications for brain repair

The potential therapeutic benefits from human umbilical cord blood (HUCB) cells for the treatment of injuries, diseases, and neurodegeneration are becoming increasingly recognized. The transplantation or infusion of cord blood cells in various animal models, such as ischemia/stroke, traumatic brain injury, myocardial infarction, Parkinson's disease, and amyotropic lateral sclerosis, has resulted in amelioration of behavioral deficits, and with some diseases, a prolonged lifespan decreased neuropathology. Previously, we reported the migration of HUCB cells to ischemic brain supernatant (tissue extracts) is time-dependent, and the expression of specific chemokines responds to this migration pattern. The mechanism(s) responsible for these effects are unknown. The expression of cytokines and chemokines produced by HUCB cells (under various culturing conditions) was investigated in this study. IL-8, MCP-1, and IL-1alpha were consistently expressed by the HUCB mononuclear cells regardless of the culture condition. These results provide insights to factors that may be partially responsible for the functional improvements seen in the animal models of injury investigating the therapeutic use of HUCB cells.