Definitions and criteria for stem cells

Safety and efficiency of Wharton's Jelly-derived mesenchymal stem cell administration in patients with traumatic brain injury: First results of a phase I study

BACKGROUND

Traumatic brain injury (TBI) is characterized by a disruption in the normal function of the brain due to an injury following a trauma, which can potentially cause severe physical, cognitive, and emotional impairment. Stem cell transplantation has evolved as a novel treatment modality in the management of TBI, as it has the potential to arrest the degeneration and promote regeneration of new cells in the brain. Wharton's Jelly-derived mesenchymal stem cells (WJ-MSCs) have recently shown beneficial effects in the functional recovery of neurological deficits.

AIM

To evaluate the safety and efficiency of MSC therapy in TBI.

METHODS

We present 6 patients, 4 male and 2 female aged between 21 and 27 years who suffered a TBI. These 6 patients underwent 6 doses of intrathecal, intramuscular (i.m.) and intravenous transplantation of WJ-MSCs at a target dose of 1 × 106/kg for each application route. Spasticity was assessed using the Modified Ashworth scale (MAS), motor function according to the Medical Research Council Muscle Strength Scale, quality of life was assessed by the Functional Independence Measure (FIM) scale and Karnofsky Performance Status scale.

RESULTS

Our patients showed only early, transient complications, such as subfebrile fever, mild headache, and muscle pain due to i.m. injection, which resolved within 24 h. During the one year follow-up, no other safety issues or adverse events were reported. These 6 patients showed improvements in their cognitive abilities, muscle spasticity, muscle strength, performance scores and fine motor skills when compared before and after the intervention. MAS values, which we used to assess spasticity, were observed to statistically significantly decrease for both left and right sides (P < 0.001). The FIM scale includes both motor scores (P < 0.05) and cognitive scores (P < 0.001) and showed a significant increase in pretest posttest analyses. The difference observed in the participants' Karnofsky Performance Scale values pre and post the intervention was statistically significant (P < 0.001).

CONCLUSION

This study showed that cell transplantation has a safe, effective and promising future in the management of TBI.

Safety and efficiency of Wharton’s Jelly-derived mesenchymal stem cell administration in patients with traumatic brain injury: First results of a phase I study

BACKGROUND

Traumatic brain injury (TBI) is characterized by a disruption in the normal function of the brain due to an injury following a trauma, which can potentially cause severe physical, cognitive, and emotional impairment. Stem cell transplantation has evolved as a novel treatment modality in the management of TBI, as it has the potential to arrest the degeneration and promote regeneration of new cells in the brain. Wharton’s Jelly-derived mesenchymal stem cells (WJ-MSCs) have recently shown beneficial effects in the functional recovery of neurological deficits.

AIM

To evaluate the safety and efficiency of MSC therapy in TBI.

METHODS

We present 6 patients, 4 male and 2 female aged between 21 and 27 years who suffered a TBI. These 6 patients underwent 6 doses of intrathecal, intramuscular (i.m.) and intravenous transplantation of WJ-MSCs at a target dose of 1 × 10⁶/kg for each application route. Spasticity was assessed using the Modified Ashworth scale (MAS), motor function according to the Medical Research Council Muscle Strength Scale, quality of life was assessed by the Functional Independence Measure (FIM) scale and Karnofsky Performance Status scale.

RESULTS

Our patients showed only early, transient complications, such as subfebrile fever, mild headache, and muscle pain due to i.m. injection, which resolved within 24 h. During the one year follow-up, no other safety issues or adverse events were reported. These 6 patients showed improvements in their cognitive abilities, muscle spasticity, muscle strength, performance scores and fine motor skills when compared before and after the intervention. MAS values, which we used to assess spasticity, were observed to statistically significantly decrease for both left and right sides (P < 0.001). The FIM scale includes both motor scores (P < 0.05) and cognitive scores (P < 0.001) and showed a significant increase in pretest posttest analyses. The difference observed in the participants’ Karnofsky Performance Scale values pre and post the intervention was statistically significant (P < 0.001).

CONCLUSION

This study showed that cell transplantation has a safe, effective and promising future in the management of TBI.

Improving Efficiency of Direct Pro-Neural Reprogramming: Much-Needed Aid for Neuroregeneration in Spinal Cord Injury

Spinal cord injury (SCI) is a medical condition affecting ~2.5-4 million people worldwide. The conventional therapy for SCI fails to restore the lost spinal cord functions; thus, novel therapies are needed. Recent breakthroughs in stem cell biology and cell reprogramming revolutionized the field. Of them, the use of neural progenitor cells (NPCs) directly reprogrammed from non-neuronal somatic cells without transitioning through a pluripotent state is a particularly attractive strategy. This allows to "scale up" NPCs in vitro and, via their transplantation to the lesion area, partially compensate for the limited regenerative plasticity of the adult spinal cord in humans. As recently demonstrated in non-human primates, implanted NPCs contribute to the functional improvement of the spinal cord after injury, and works in other animal models of SCI also confirm their therapeutic value. However, direct reprogramming still remains a challenge in many aspects; one of them is low efficiency, which prevents it from finding its place in clinics yet. In this review, we describe new insights that recent works brought to the field, such as novel targets (mitochondria, nucleoli, G-quadruplexes, and others), tools, and approaches (mechanotransduction and electrical stimulation) for direct pro-neural reprogramming, including potential ones yet to be tested.

Isolation and Culture of Neural Stem/Progenitor Cells from the Postnatal Periventricular Region

Due to the complexity of the neural stem cell (NSC) niche organization, the lack of specific NSC markers, and the difficulty of long-term tracking these cells and their progeny in vivo, the functional properties of the endogenous NSCs remain largely unexplored. These limitations have led to the development of methodologies to efficiently isolate, expand, and differentiate NSCs ex vivo. We describe here the peculiarities of the neurosphere assay (NSA) as a methodology that allows to efficiently isolate, expand, and differentiate somatic NSCs derived from the postnatal and adult forebrain periventricular region while preserving proliferation, self-renewal, and multipotency, the main attributes that provide their functional identification.

Biotechnology and Biomaterial-Based Therapeutic Strategies for Age-Related Macular Degeneration. Part II: Cell and Tissue Engineering Therapies

Age-related Macular Degeneration (AMD) is an up-to-date untreatable chronic neurodegenerative eye disease of multifactorial origin, and the main causes of blindness in over 65 y.o. people. It is characterized by a slow progression and the presence of a multitude of factors, highlighting those related to diet, genetic heritage and environmental conditions, present throughout each of the stages of the illness. Current therapeutic approaches, mainly consisting on intraocular drug delivery, are only used for symptoms relief and/or to decelerate the progression of the disease. Furthermore, they are overly simplistic and ignore the complexity of the disease and the enormous differences in the symptomatology between patients. Due to the wide impact of the AMD and the up-to-date absence of clinical solutions, Due to the wide impact of the AMD and the up-to-date absence of clinical solutions, different treatment options have to be considered. Cell therapy is a very promising alternative to drug-based approaches for AMD treatment. Cells delivered to the affected tissue as a suspension have shown poor retention and low survival rate. A solution to these inconveniences has been the encapsulation of these cells on biomaterials, which contrive to their protection, gives them support, and favor their retention of the desired area. We offer a two-papers critical review of the available and under development AMD therapeutic approaches, from a biomaterials and biotechnological point of view. We highlight benefits and limitations and we forecast forthcoming alternatives based on novel biomaterials and biotechnology methods. In this second part we review the preclinical and clinical cell-replacement approaches aiming at the development of efficient AMD-therapies, the employed cell types, as well as the cell-encapsulation and cell-implant systems. We discuss their advantages and disadvantages and how they could improve the survival and integration of the implanted cells.

Enhancement of Hippocampal Plasticity by Physical Exercise as a Polypill for Stress and Depression: A Review

Generation of newborn neurons that form functional synaptic connections in the dentate gyrus of adult mammals, known as adult hippocampal neurogenesis, has been suggested to play critical roles in regulating mood, as well as certain forms of hippocampus-dependent learning and memory. Environmental stress suppresses structural plasticity including adult neurogenesis and dendritic remodeling in the hippocampus, whereas physical exercise exerts opposite effects. Here, we review recent discoveries on the potential mechanisms concerning how physical exercise mitigates the stressrelated depressive disorders, with a focus on the perspective of modulation on hippocampal neurogenesis, dendritic remodeling and synaptic plasticity. Unmasking such mechanisms may help devise new drugs in the future for treating neuropsychiatric disorders involving impaired neural plasticity.

Neuronal and astrocytic primary cilia in the mature brain

Primary cilia are tiny microtubule-based signaling devices that regulate a variety of physiological functions, including metabolism and cell division. Defects in primary cilia lead to a myriad of diseases in humans such as obesity and cancers. In the mature brain, both neurons and astrocytes contain a single primary cilium. Although neuronal primary cilia are not directly involved in synaptic communication, their pathophysiological impacts on obesity and mental disorders are well recognized. In contrast, research on astrocytic primary cilia lags far behind. Currently, little is known about their functions and molecular pathways in the mature brain. Unlike neurons, postnatal astrocytes retain the capacity of cell division and can become reactive and proliferate in response to various brain insults such as epilepsy, ischemia, traumatic brain injury, and neurodegenerative β-amyloid plaques. Since primary cilia derive from the mother centrioles, astrocyte proliferation must occur in coordination with the dismantling and ciliogenesis of astrocyte cilia. In this regard, the functions, signal pathways, and structural dynamics of neuronal and astrocytic primary cilia are fundamentally different. Here we discuss and compare the current understanding of neuronal and astrocytic primary cilia.

CD73, CD90, CD105 and Cadherin-11 RT-PCR Screening for Mesenchymal Stem Cells from Cryopreserved Human Cord Tissue

Background and Objectives

Mesenchymal stem cells (MSCs) are self-renewing, non-specialized cells used clinically in tissue regeneration and sourced from bone marrow, peripheral blood, umbilical cord blood and umbilical cord tissue (UCT). To demonstrate an alternative method for MSC detection, cryopreserved UCT and expanded MSC were screened for MSC markers CD73, CD90, CD105 and CDH-11 by RT-PCR.

Methods and Results

Human UCT were washed, sectioned, cryopreserved with 10% DMSO and stored in the vapor phase of liquid nitrogen. Fresh and frozen UCT samples were expanded for MSC. UCT and MSC were processed for RNA and screened for CD73, CD90, CD105 and CDH-11 mRNA by RT-PCR. CD73, CD90 and CD105 were detected by flow cytometry and CDH-11 was detected by Western blotting. Short and long-term frozen UCT shows a loss of mRNA expression for CD73 at 33.2±34.0%, CD90 at 6.2±8.2%, CD105 at 17.7±21.6% and CDH-11 at 30.1±26.7% but was not statistically significant to indicate the deterioration. Expanded MSCs from fresh UCT expressed 0.09±0.07-fold CD73, 0.17±0.11-fold CD90, 0.04±0.06-fold CD105 and 0.14±0.08-fold CDH-11. Expanded MSCs from frozen UCTs expressed 0.09±0.06-fold CD73, 0.13±0.06-fold CD90, 0.04±0.05-fold CD105 and 0.11±0.06-fold CDH-11 and confirmed by flow cytometry and Western blotting.

Conclusion

CD73, CD90, CD105 and CDH-11 were detected by RT-PCR in cryopreserved UCT and MSC expansion. CDH-11 appears as a useful single target MSC marker for quick screening.

Bone Marrow-Derived Stem Cells Protect against Haloperidol-Induced Brain and Liver Damage in Mice

We studied the effect of bone marrow-derived stem cells (BM-SCs) on oxidative stress, inflammation and pathological changes induced in the brain and liver of mice by the antipsychotic drug haloperidol. Mice were intraperitoneally (i.p.) treated with haloperidol at 5 mg/kg for 3 consecutive days followed by i.p. stem cell suspension and euthanized 24h later. Haloperidol resulted in increased brain and liver malondialdehyde (MDA) and nitric oxide contents together with decreased reduced glutathione (GSH). There were also decreased paraoxonase-1 (PON-1) activity in brain and liver and increased interleukin-1β (IL-1 β), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) in brain tissue. Haloperidol produced neuronal necrosis and apoptosis and the appearance of esinophilic areas and strong TNF-α immunoreactivity in the cerebral cortex and striatum of treated mice. In the liver, centrilobular necrosis, inflammatory cell infiltration and sinusoidal haemorrhage were observed. In haloperidol-treated mice, stem cell injection had no significant effects on brain and liver levels of MDA, nitric oxide or GSH. Paraoxonase-1 activity in brain, however, decreased by stem cells application. In brain, there were decreased IL-1β, IL-6 and TNF-α. Brain neurodegenerative changes, brain TNF-immunoreactivity and histological liver damage were all markedly ameliorated after stem cell treatment. These results indicate that stem cells protect against brain and liver toxicity caused by short term haloperidol treatment in high dose. The protective effects of stem cell treatment is likely to result from interfering with cytokine release.

The Potential of microRNAs for Stem Cell-based Therapy for Degenerative Skeletal Diseases

Purpose of Review

Degenerative skeletal disorders including osteoarthritis (OA) and osteoporosis (OP) are the result of attenuation of tissue regeneration and lead to painful conditions with limited treatment options. Preventative measures to limit the onset of OA and OP remain a significant unmet clinical need. MicroRNAs (miRNAs) are known to be involved in the differentiation of stem cells, and in combination with stem cell therapy could induce skeletal regeneration and potentially prevent OA and OP onset.

Recent Findings

The combination of stem cells and miRNA has been successful at regenerating the bone and cartilage in vivo. MiRNAs, including miR-146b known to be involved in chondrogenic differentiation, could provide innovative targets for stem cell-based therapy, for the repair of articular cartilage defects forestalling the onset of OA or in the generation of a stem cell-based therapy for OP.

Summary

This review discusses the combination of skeletal stem cells (SSCs) and candidate miRNAs for application in a cell-based therapy approach for skeletal regenerative medicine.

Adrenal cortical and chromaffin stem cells: Is there a common progeny related to stress adaptation?

The adrenal gland is a highly plastic organ with the capacity to adapt the body homeostasis to different physiological needs. The existence of stem-like cells in the adrenal cortex has been revealed in many studies. Recently, we identified and characterized in mice a pool of glia-like multipotent Nestin-expressing progenitor cells, which contributes to the plasticity of the adrenal medulla. In addition, we found that these Nestin progenitors are actively involved in the stress response by giving rise to chromaffin cells. Interestingly, we also observed a Nestin-GFP-positive cell population located under the adrenal capsule and scattered through the cortex. In this article, we discuss the possibility of a common progenitor giving rise to subpopulations of cells both in the adrenal cortex and medulla, the isolation and characterization of this progenitor as well as its clinical potential in transplantation therapies and in pathophysiology.

Bone marrow mesenchymal stem cell therapy for voiding dysfunction

Lower urinary tract symptoms can significantly impact quality of life. Current standard treatments are not always effective and are associated with complications and side effects. The discovery of stem cells led to research into cell-based therapies for treatment of disorders of voiding dysfunction. Bone marrow mesenchymal stem cells are particularly promising given their ability to differentiate into a variety of cell types. Recent studies have investigated bone marrow stem cells to treat a number of functional voiding pathologies including bladder outlet obstruction, neurogenic bladder, and stress urinary incontinence. Experiments in tissue regeneration have also attempted to create artificial bladders and urethras. The purpose of this article is to critically review the literature regarding the use of bone marrow mesenchymal stem cells in treatment of voiding dysfunction.

Biomechanical conditioning of tissue engineered heart valves: Too much of a good thing?

Surgical replacement of dysfunctional valves is the primary option for the treatment of valvular disease and congenital defects. Existing mechanical and bioprosthetic replacement valves are far from ideal, requiring concomitant anticoagulation therapy or having limited durability, thus necessitating further surgical intervention. Heart valve tissue engineering (HVTE) is a promising alternative to existing replacement options, with the potential to synthesize mechanically robust tissue capable of growth, repair, and remodeling. The clinical realization of a bioengineered valve relies on the appropriate combination of cells, biomaterials, and/or bioreactor conditioning. Biomechanical conditioning of valves in vitro promotes differentiation of progenitor cells to tissue-synthesizing myofibroblasts and prepares the construct to withstand the complex hemodynamic environment of the native valve. While this is a crucial step in most HVTE strategies, it also may contribute to fibrosis, the primary limitation of engineered valves, through sustained myofibrogenesis. In this review, we examine the progress of HVTE and the role of mechanical conditioning in the synthesis of mechanically robust tissue, and suggest approaches to achieve myofibroblast quiescence and prevent fibrosis.

Injury in aged animals robustly activates quiescent olfactory neural stem cells

While the capacity of the olfactory epithelium (OE) to generate sensory neurons continues into middle age in mice, it is presumed that this regenerative potential is present throughout all developmental stages. However, little experimental evidence exists to support the idea that this regenerative capacity remains in late adulthood, and questions about the functionality of neurons born at these late stages remain unanswered. Here, we extend our previous work in the VNO to investigate basal rates of proliferation in the OE, as well as after olfactory bulbectomy (OBX), a commonly used surgical lesion. In addition, we show that the neural stem cell retains its capacity to generate mature olfactory sensory neurons in aged animals. Finally, we demonstrate that regardless of age, a stem cell in the OE, the horizontal basal cell (HBC), exhibits a morphological switch from a flattened, quiescent phenotype to a pyramidal, proliferative phenotype following chemical lesion in aged animals. These findings provide new insights into determining whether an HBC is active or quiescent based on a structural feature as opposed to a biochemical one. More importantly, it suggests that neural stem cells in aged mice are responsive to the same signals triggering proliferation as those observed in young mice.

Delivery strategies for treatment of age-related ocular diseases: From a biological understanding to biomaterial solutions

Age-related ocular diseases, such as age-related macular degeneration (AMD), diabetic retinopathy, and glaucoma, result in life-long functional deficits and enormous global health care costs. As the worldwide population ages, vision loss has become a major concern for both economic and human health reasons. Due to recent research into biomaterials and nanotechnology major advances have been gained in the field of ocular delivery. This review provides a summary and discussion of the most recent strategies employed for the delivery of both drugs and cells to the eye to treat a variety of age-related diseases. It emphasizes the current challenges and limitations to ocular delivery and how the use of innovative materials can overcome these issues and ultimately provide treatment for age-related degeneration and regeneration of lost tissues. This review also provides critical considerations and an outlook for future studies in the field of ophthalmic delivery.

Adrenomedullary progenitor cells: Isolation and characterization of a multi-potent progenitor cell population

The adrenal is a highly plastic organ with the ability to adjust to physiological needs by adapting hormone production but also by generating and regenerating both adrenocortical and adrenomedullary tissue. It is now apparent that many adult tissues maintain stem and progenitor cells that contribute to their maintenance and adaptation. Research from the last years has proven the existence of stem and progenitor cells also in the adult adrenal medulla throughout life. These cells maintain some neural crest properties and have the potential to differentiate to the endocrine and neural lineages. In this article, we discuss the evidence for the existence of adrenomedullary multi potent progenitor cells, their isolation and characterization, their differentiation potential as well as their clinical potential in transplantation therapies but also in pathophysiology.

Mesenchymal Stromal Cell Dependent Regression of Pulmonary Metastasis from Ewing's

INTRODUCTION

Ewing's sarcoma (ES) is the second most common bone tumor in children. Survival has not improved over the last decade and once pulmonary metastatic disease is present, survival is dismal. Mesenchymal stromal cell (MSC) therapy has shown potential benefit for Kaposi's sarcoma; however, the role of progenitor cell therapies for cancer remains controversial. MSC treatment of ES or pulmonary metastatic disease has not been demonstrated. We have developed an orthotopic xenograft model of ES in which animals develop spontaneous pulmonary metastases. Within this model, we demonstrate the use of MSCs to target ES lung metastasis.

MATERIALS AND METHODS

Human ES cells were transfected with luciferase and injected into the rib of nude mice. Development of pulmonary metastases was confirmed by imaging. After flow cytometry based characterization, MSCs were injected into the tail vein of nude mice with established local ES tumor or pulmonary metastasis. Mice were treated with intravenous MSCs weekly followed by bioluminescent imaging.

RESULTS

The intravenous injection of MSCs in an ES model decreases the volume of pulmonary metastatic lesions; however, no effect on primary chest wall tumor size is observed. Thus verifying the MSC preferential homing to the lung. MSCs are found to "home to" the pulmonary parenchyma and remain engrafted up to 5 days after delivery.

DISCUSSION

MSC treatment of ES slows growth of pulmonary metastasis. MSCs have more affinity for pulmonary metastasis and can effect a greater decrease in tumor growth in the lungs compared to the primary tumor site.

Neural stem cells-trends and advances

For many years, accepted dogma held that brain is a static organ with no possibility of regeneration of cells in injured or diseased human brain. However, recent preclinical reports have shown regenerative potential of neural stem cells using various injury models. This has resulted in renewed hope for those suffering from spinal cord injury and neural damage. As the potential of stem cell therapy gained impact, these claims, in particular, led to widespread enthusiasm that acute and chronic injury of the nervous system would soon be a problem of the past. The devastation caused by injury or diseases of the brain and spinal cord led to wide premature acceptance that "neural stem cells (NSCs)" derived from embryonic, fetal or adult sources would soon be effective in reversing neural and spinal trauma. However, neural therapy with stem cells has not been realized to its fullest extent. Although, discrete population of regenerative stem cells seems to be present in specific areas of human brain, the function of these cells is unclear. However, similar cells in animals seem to play important role in postnatal growth as well as recovery of neural tissue from injury, anoxia, or disease.

Organ engineering--combining stem cells, biomaterials, and bioreactors to produce bioengineered organs for transplantation

Often the only treatment available for patients suffering from diseased and injured organs is whole organ transplant. However, there is a severe shortage of donor organs for transplantation. The goal of organ engineering is to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. Recent progress in stem cell biology, biomaterials, and processes such as organ decellularization and electrospinning has resulted in the generation of bioengineered blood vessels, heart valves, livers, kidneys, bladders, and airways. Future advances that may have a significant impact for the field include safe methods to reprogram a patient's own cells to directly differentiate into functional replacement cell types. The subsequent combination of these cells with natural, synthetic and/or decellularized organ materials to generate functional tissue substitutes is a real possibility. This essay reviews the current progress, developments, and challenges facing researchers in their goal to create replacement tissues and organs for patients.

Intestinal tissue engineering: current concepts and future vision of regenerative medicine in the gut

Functional tissue engineering of the gastrointestinal (GI) tract is a complex process aiming to aid the regeneration of structural layers of smooth muscle, intrinsic enteric neuronal plexuses, specialized mucosa, and epithelial cells as well as interstitial cells. The final tissue-engineered construct is intended to mimic the native GI tract anatomically and physiologically. Physiological functionality of tissue-engineered constructs is of utmost importance while considering clinical translation. The construct comprises of cellular components as well as biomaterial scaffolding components. Together, these determine the immune response a tissue-engineered construct would elicit from a host upon implantation. Over the last decade, significant advances have been made to mitigate adverse host reactions. These include a quest for identifying autologous cell sources like embryonic and adult stem cells, bone marrow-derived cells, neural crest-derived cells, and muscle derived-stem cells. Scaffolding biomaterials have been fabricated with increasing biocompatibility and biodegradability. Manufacturing processes have advanced to allow for precise spatial architecture of scaffolds to mimic in vivo milieu closely and achieve neovascularization. This review will focus on the current concepts and the future vision of functional tissue engineering of the diverse neuromuscular structures of the GI tract from the esophagus to the internal anal sphincter.

Tissue engineering: current strategies and future directions

Novel therapies resulting from regenerative medicine and tissue engineering technology may offer new hope for patients with injuries, end-stage organ failure, or other clinical issues. Currently, patients with diseased and injured organs are often treated with transplanted organs. However, there is a shortage of donor organs that is worsening yearly as the population ages and as the number of new cases of organ failure increases. Scientists in the field of regenerative medicine and tissue engineering are now applying the principles of cell transplantation, material science, and bioengineering to construct biological substitutes that can restore and maintain normal function in diseased and injured tissues. In addition, the stem cell field is a rapidly advancing part of regenerative medicine, and new discoveries in this field create new options for this type of therapy. For example, new types of stem cells, such as amniotic fluid and placental stem cells that can circumvent the ethical issues associated with embryonic stem cells, have been discovered. The process of therapeutic cloning and the creation of induced pluripotent cells provide still other potential sources of stem cells for cell-based tissue engineering applications. Although stem cells are still in the research phase, some therapies arising from tissue engineering endeavors that make use of autologous, adult cells have already entered the clinical setting, indicating that regenerative medicine holds much promise for the future.

Progenitor cells as remote "bioreactors": neuroprotection via modulation of the systemic inflammatory response

Acute central nervous system (CNS) injuries such as spinal cord injury, traumatic brain injury, autoimmune encephalomyelitis, and ischemic stroke are associated with significant morbidity, mortality, and health care costs worldwide. Preliminary research has shown potential neuroprotection associated with adult tissue derived stem/progenitor cell based therapies. While initial research indicated that engraftment and transdifferentiation into neural cells could explain the observed benefit, the exact mechanism remains controversial. A second hypothesis details localized stem/progenitor cell engraftment with alteration of the loco-regional milieu; however, the limited rate of cell engraftment makes this theory less likely. There is a growing amount of preclinical data supporting the idea that, after intravenous injection, stem/progenitor cells interact with immunologic cells located in organ systems distant to the CNS, thereby altering the systemic immunologic/inflammatory response. Such distant cell "bioreactors" could modulate the observed post-injury pro-inflammatory environment and lead to neuroprotection. In this review, we discuss the current literature detailing the above mechanisms of action for adult stem/progenitor cell based therapies in the CNS.

Adult Hippocampal Neurogenesis: A Possible Way how Physical Exercise Counteracts Stress

It was considered that neurogenesis only occurred during the embryonic and developmental stage. This view has greatly changed since the discovery of adult neurogenesis in two brain regions: the hippocampus and the olfactory bulb. Recently, it is suggested that altered hippocampal neurogenesis is related to pathophysiology of mood disorders and mechanism of antidepressant treatments. Accumulating knowledge about the effects of physical exercise on brain function suggests a special role of adult hippocampal neurogenesis in cognitive and mental health, even though the functional significance of adult neurogenesis is still debated. The beneficial effects of running correlating with increased adult neurogenesis may provide a hint that newborn neurons may be involved, at least in part, in the counteractive mechanism of physical exercise on stress-related disorders, like depression. The present review provides an overview of recent findings to emphasize the possible involvement of hippocampal neurogenesis in mediating the beneficial effects of physical exercise on counteracting stress.

Tissue engineering of human bladder

There are a number of conditions of the bladder that can lead to loss of function. Many of these require reconstructive procedures. However, current techniques may lead to a number of complications. Replacement of bladder tissues with functionally equivalent ones created in the laboratory could improve the outcome of reconstructive surgery. A review of the literature was conducted using PubMed to identify studies that provide evidence that tissue engineering techniques may be useful in the development of alternatives to current methods of bladder reconstruction. A number of animal studies and several clinical experiences show that it is possible to reconstruct the bladder using tissues and neo-organs produced in the laboratory. Materials that could be used to create functionally equivalent urologic tissues in the laboratory, especially non-autologous cells that have the potential to reject have many technical limitations. Current research suggests that the use of biomaterial-based, bladder-shaped scaffolds seeded with autologous urothelial and smooth muscle cells is currently the best option for bladder tissue engineering. Further research to develop novel biomaterials and cell sources, as well as information gained from developmental biology, signal transduction studies and studies of the wound healing response would be beneficial.

Progenitor cell therapy for the treatment of central nervous system injury: a review of the state of current clinical trials

Recent preclinical work investigating the role of progenitor cell therapies for central nervous system (CNS) injuries has shown potential neuroprotection in the setting of traumatic brain injury (TBI), spinal cord injury (SCI), and ischemic stroke. Mechanisms currently under investigation include engraftment and transdifferentiation, modulation of the locoregional inflammatory milieu, and modulation of the systemic immunologic/inflammatory response. While the exact mechanism of action remains controversial, the growing amount of preclinical data demonstrating the potential benefit associated with progenitor cell therapy for neurological injury warrants the development of well-controlled clinical trials to investigate therapeutic safety and efficacy. In this paper, we review the currently active or recently completed clinical trials investigating the safety and potential efficacy of bone marrow-derived progenitor cell therapies for the treatment of TBI, SCI, and ischemic stroke. Our review of the literature shows that while the preliminary clinical trials reviewed in this paper offer novel data supporting the potential efficacy of stem/progenitor cell therapies for CNS injury, a great deal of additional work is needed to ensure the safety, efficacy, and mechanisms of progenitor cell therapy prior to widespread clinical trials.

Overexpression of metallothioneins, stem cell niches and field cancerization in experimental gliomagenesis

INTRODUCTION: stem cells may originate and perpetuate the tumor growth, but they are poorly known in gliomagenesis. Metallothioneins (MTs) are proteins involved in oncogenesis and immunopositivity, for MT may be used as a stem cell mutation marker. OBJECTIVE: to study the MT expression in the ENU experimental model and to establish an experimental model to track glioma stem cells in early oncogenesis. METHODS: Thirty-six male Wistar rats were divided into two groups; the experimental group was treated within 24 hours after birth (neonate rats) with a single dose of subcutaneously injected N-ethyl N-nitrosourea ENU (40 mg/kg body weight). The control animals were injected with the same volume of saline. These experimental animals were subdivided into three groups according to the euthanize time, as follows: the Group 1 (G1) was euthanized at the age of 30 days; the Group 2 (G2), at the age of 180 days and the Group 3 (G3) was euthanized soon after the appearing of signs of the existence of nervous system tumors, at an average age of 321 days. Immunohistochemical detection of MT protein in cold acetone-fixed paraffin embedded spine cord sections was performed by the streptavidin-avidin-biotin-immuno peroxidase complex method. RESULTS: by using the experimental model of gliomagenesis induced by the N-ethyl N-nitrosourea, it was possible to detect putative tumor stem cells in early oncogenesis, to analyze a field cancerization process and to observe a close morphological relationship between MT positive cells and blood vessels. CONCLUSIONS: this reproducible experimental model allows further studies on the origins, development and regulating factors involved in gliomagenesis.

Advances in progenitor cell therapy using scaffolding constructs for central nervous system injury

Traumatic brain injury (TBI) is a major cause of morbidity and mortality in the United States. Current clinical therapy is focused on optimization of the acute/subacute intracerebral milieu, minimizing continued cell death, and subsequent intense rehabilitation to ameliorate the prolonged physical, cognitive, and psychosocial deficits that result from TBI. Adult progenitor (stem) cell therapies have shown promise in pre-clinical studies and remain a focus of intense scientific investigation. One of the fundamental challenges to successful translation of the large body of pre-clinical work is the delivery of progenitor cells to the target location/organ. Classically used vehicles such as intravenous and intra arterial infusion have shown low engraftment rates and risk of distal emboli. Novel delivery methods such as nanofiber scaffold implantation could provide the structural and nutritive support required for progenitor cell proliferation, engraftment, and differentiation. The focus of this review is to explore the current state of the art as it relates to current and novel progenitor cell delivery methods.

Modern approaches to pediatric brain injury therapy

Each year, pediatric traumatic brain injury (TBI) accounts for 435,000 emergency department visits, 37,000 hospital admissions, and approximately 2,500 deaths in the United States. TBI results in immediate injury from direct mechanical force and shear. Secondary injury results from the release of biochemical or inflammatory factors that alter the loco-regional milieu in the acute, subacute, and delayed intervals after a mechanical insult. Preliminary preclinical and clinical research is underway to evaluate the benefit from progenitor cell therapeutics, hypertonic saline infusion, and controlled hypothermia. However, all phase III clinical trials investigating pharmacologic monotherapy for TBI have shown no benefit. A recent National Institutes of Health consensus statement recommends research into multimodality treatments for TBI. This article will review the complex pathophysiology of TBI as well as the possible therapeutic mechanisms of progenitor cell transplantation, hypertonic saline infusion, and controlled hypothermia for possible utilization in multimodality clinical trials.

Progenitor cell therapies for traumatic brain injury: barriers and opportunities in translation

Traumatic brain injury (TBI) directly affects nearly 1.5 million new patients per year in the USA, adding to the almost 6 million cases in patients who are permanently affected by the irreversible physical, cognitive and psychosocial deficits from a prior injury. Adult stem cell therapy has shown preliminary promise as an option for treatment, much of which is limited currently to supportive care. Preclinical research focused on cell therapy has grown significantly over the last decade. One of the challenges in the translation of this burgeoning field is interpretation of the promising experimental results obtained from a variety of cell types, injury models and techniques. Although these variables can become barriers to a collective understanding and to evidence-based translation, they provide crucial information that, when correctly placed, offers the opportunity for discovery. Here, we review the preclinical evidence that is currently guiding the translation of adult stem cell therapy for TBI.

Stem cells in urology

The shortage of donors for organ transplantation has stimulated research on stem cells as a potential resource for cell-based therapy in all human tissues. Stem cells have been used for regenerative medicine applications in many organ systems, including the genitourinary system. The potential applications for stem cell therapy have, however, been restricted by the ethical issues associated with embryonic stem cell research. Instead, scientists have explored other cell sources, including progenitor and stem cells derived from adult tissues and stem cells derived from the amniotic fluid and placenta. In addition, novel techniques for generating stem cells in the laboratory are being developed. These techniques include somatic cell nuclear transfer, in which the nucleus of an adult somatic cell is placed into an oocyte, and reprogramming of adult cells to induce stem-cell-like behavior. Such techniques are now being used in tissue engineering applications, and some of the most successful experiments have been in the field of urology. Techniques to regenerate bladder tissue have reached the clinic, and exciting progress is being made in other areas, such as regeneration of the kidney and urethra. Cell therapy as a treatment for incontinence and infertility might soon become a reality. Physicians should be optimistic that regenerative medicine and tissue engineering will one day provide mainstream treatment options for urologic disorders.