Stem cells for the treatment of neurological disease

The Use of Stem Cells as a Potential Treatment Method for Selected Neurodegenerative Diseases: Review

Stem cells have been the subject of research for years due to their enormous therapeutic potential. Most neurological diseases such as multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD) are incurable or very difficult to treat. Therefore new therapies are sought in which autologous stem cells are used. They are often the patient's only hope for recovery or slowing down the progress of the disease symptoms. The most important conclusions arise after analyzing the literature on the use of stem cells in neurodegenerative diseases. The effectiveness of MSC cell therapy has been confirmed in ALS and HD therapy. MSC cells slow down ALS progression and show early promising signs of efficacy. In HD, they reduced huntingtin (Htt) aggregation and stimulation of endogenous neurogenesis. MS therapy with hematopoietic stem cells (HSCs) inducted significant recalibration of pro-inflammatory and immunoregulatory components of the immune system. iPSC cells allow for accurate PD modeling. They are patient-specific and therefore minimize the risk of immune rejection and, in long-term observation, did not form any tumors in the brain. Extracellular vesicles derived from bone marrow mesenchymal stromal cells (BM-MSC-EVs) and Human adipose-derived stromal/stem cells (hASCs) cells are widely used to treat AD. Due to the reduction of Aβ42 deposits and increasing the survival of neurons, they improve memory and learning abilities. Despite many animal models and clinical trial studies, cell therapy still needs to be refined to increase its effectiveness in the human body.

Stem Cell Transplantation Therapy and Neurological Disorders: Current Status and Future Perspectives

Neurodegenerative diseases are a global health issue with inadequate therapeutic options and an inability to restore the damaged nervous system. With advances in technology, health scientists continue to identify new approaches to the treatment of neurodegenerative diseases. Lost or injured neurons and glial cells can lead to the development of several neurological diseases, including Parkinson's disease, stroke, and multiple sclerosis. In recent years, neurons and glial cells have successfully been generated from stem cells in the laboratory utilizing cell culture technologies, fueling efforts to develop stem cell-based transplantation therapies for human patients. When a stem cell divides, each new cell has the potential to either remain a stem cell or differentiate into a germ cell with specialized characteristics, such as muscle cells, red blood cells, or brain cells. Although several obstacles remain before stem cells can be used for clinical applications, including some potential disadvantages that must be overcome, this cellular development represents a potential pathway through which patients may eventually achieve the ability to live more normal lives. In this review, we summarize the stem cell-based therapies that have been explored for various neurological disorders, discuss the potential advantages and drawbacks of these therapies, and examine future directions for this field.

Genetically Encoded Self-Assembling Iron Oxide Nanoparticles as a Possible Platform for Cancer-Cell Tracking

The study of growth and possible metastasis in animal models of tumors would benefit from reliable cell labels for noninvasive whole-organism imaging techniques such as magnetic resonance imaging. Genetically encoded cell-tracking reporters have the advantage that they are contrast-selective for viable cells with intact protein expression machinery. Besides, these reporters do not suffer from dilution during cell division. Encapsulins, which are bacterial protein nanocompartments, can serve as genetically controlled labels for multimodal detection of cells. Such nanocompartments can host various guest molecules inside their lumen. These include, for example, fluorescent proteins or enzymes with ferroxidase activity leading to biomineralization of iron oxide inside the encapsulin nanoshell. The aim of this work was to implement heterologous expression of encapsulin systems from Quasibacillus thermotolerans using the fluorescent reporter protein mScarlet-I and ferroxidase IMEF in the human hepatocellular carcinoma cell line HepG2. The successful expression of self-assembled encapsulin nanocompartments with functional cargo proteins was confirmed by fluorescence microscopy and transmission electron microscopy. Also, coexpression of encapsulin nanoshells, ferroxidase cargo, and iron transporter led to an increase in T₂-weighted contrast in magnetic resonance imaging of HepG2 cells. The results demonstrate that the encapsulin cargo system from Q. thermotolerans may be suitable for multimodal imaging of cancer cells and could contribute to further in vitro and in vivo studies.

Molecular Imaging of Stem Cells

Regenerative medicine with the use of stem cells has appeared as a potential therapeutic alternative for many disease states. Despite initial enthusiasm, there has been relatively slow transition to clinical trials. In large part, numerous questions remain regarding the viability, biology and efficacy of transplanted stem cells in the living subject. The critical issues highlighted the importance of developing tools to assess these questions. Advances in molecular biology and imaging have allowed the successful non-invasive monitoring of transplanted stem cells in the living subject. Over the years these methodologies have been updated to assess not only the viability but also the biology of transplanted stem cells. In this review, different imaging strategies to study the viability and biology of transplanted stem cells are presented. Use of these strategies will be critical as the different regenerative therapies are being tested for clinical use.

Ethical clinical translation of stem cell interventions for neurologic disease

The application of stem cell transplants in clinical practice has increased in frequency in recent years. Many of the stem cell transplants in neurologic diseases, including stroke, Parkinson disease, spinal cord injury, and demyelinating diseases, are unproven-they have not been tested in prospective, controlled clinical trials and have not become accepted therapies. Stem cell transplant procedures currently being carried out have therapeutic aims, but are frequently experimental and unregulated, and could potentially put patients at risk. In some cases, patients undergoing such operations are not included in a clinical trial, and do not provide genuinely informed consent. For these reasons and others, some current stem cell interventions for neurologic diseases are ethically dubious and could jeopardize progress in the field. We provide discussion points for the evaluation of new stem cell interventions for neurologic disease, based primarily on the new Guidelines for Stem Cell Research and Clinical Translation released by the International Society for Stem Cell Research in May 2016. Important considerations in the ethical translation of stem cells to clinical practice include regulatory oversight, conflicts of interest, data sharing, the nature of investigation (e.g., within vs outside of a clinical trial), informed consent, risk-benefit ratios, the therapeutic misconception, and patient vulnerability. To help guide the translation of stem cells from the laboratory into the neurosurgical clinic in an ethically sound manner, we present an ethical discussion of these major issues at stake in the field of stem cell clinical research for neurologic disease.

Mesenchymal stem cell treatment for chronic renal failure

Chronic renal failure is an important clinical problem with significant socioeconomic impact worldwide. Despite advances in renal replacement therapies and organ transplantation, poor quality of life for dialysis patients and long transplant waiting lists remain major concerns for nephrologists treating this condition. There is therefore a pressing need for novel therapies to promote renal cellular repair and tissue remodeling. Over the past decade, advances in the field of regenerative medicine allowed development of cell therapies suitable for kidney repair. Mesenchymal stem cells (MSCs) are undifferentiated cells that possess immunomodulatory and tissue trophic properties and the ability to differentiate into multiple cell types. Studies in animal models of chronic renal failure have uncovered a unique potential of these cells for improving function and regenerating the damaged kidney. Nevertheless, several limitations pertaining to inadequate engraftment, difficulty to monitor, and untoward effects of MSCs remain to be addressed. Adverse effects observed following intravascular administration of MSCs include immune rejection, adipogenic differentiation, malignant transformation, and prothrombotic events. Nonetheless, most studies indicate a remarkable capability of MSCs to achieve kidney repair. This review summarizes the regenerative potential of MSCs to provide functional recovery from renal failure, focusing on their application and the current challenges facing clinical translation.

Coleta e cultura de células-tronco obtidas da polpa de dentes decíduos: técnica e relato de caso clínico

INTRODUÇÃO: as células-tronco (CT) possuem capacidade de induzir a regeneração tecidual e, portanto, apresentam um potencial terapêutico. Assim como a medula óssea e o cordão umbilical, a polpa dentária é uma das fontes disponíveis de CT. O seu fácil acesso e o fato de os dentes decíduos não serem órgãos vitais, que normalmente são descartados após a esfoliação, provêm um atrativo para testes de segurança e viabilidade terapêutica dessas células. OBJETIVOS: descrever a coleta, o isolamento e o cultivo de CT obtidas da polpa de dentes decíduos, assim como a sua caracterização por meio de citometria de fluxo e da indução da diferenciação em linhagens osteogênica e adipogênica. MÉTODOS: as CT foram obtidas de forma relativamente simples e apresentaram boa capacidade proliferativa, mesmo a partir de pouca quantidade de tecido pulpar. RESULTADOS: a análise por citometria de fluxo confirmou as características de CT mesenquimais, com baixos níveis de expressão dos antígenos CD34 e CD45, que são marcadores de células hematopoiéticas, e altos níveis de expressão dos antígenos CD105, CD166, CD90 e CD73, que são marcadores de CT mesenquimais. A plasticidade das células foi confirmada pela identificação de depósitos de cálcio nas culturas que receberam meio osteogênico, e de acúmulo lipídico intracelular nas culturas que receberam meio adipogênico. CONCLUSÕES: as CT de dentes decíduos têm um potencial promissor de aplicação em regeneração tecidual. Sendo assim, é importante difundir entre os cirurgiões-dentistas o conhecimento sobre a existência e as características dessa fonte de CT, discutindo a técnica utilizada, suas limitações e possíveis indicações.

Molecular imaging of cell therapy for gastroenterologic applications

Stem cell therapy has appeared as a possible therapeutic alternative for numerous diseases. Furthermore, cancer stem cells are a focus of significant interest as they may allow for a better understanding of the genesis of different malignancies. The ultimate goal of stem cell therapeutics is to ensure the viability and functionality of the transplanted cells. Similarly, the ultimate goal of understanding cancer stem cells is to understand how they behave in the living subject. Until recently, the efficacy of stem cell therapies has been assessed by overall organ function recovery. Understanding the behavior and biology of stem cells directly in the living subject can also lead to therapy optimization. Thus, there is a critical need for reliable and accurate methods to understand stem cell biology in vivo. Recent advances in both imaging and molecular biology have enabled transplanted stem cells to be successfully monitored in the living subject. The use of molecular imaging modalities has the capability to answer these questions and may one day be translated to patients. In this review, we will discuss the potential imaging strategies and how they can be utilized, depending on the questions that need to be answered.

[Stem cells use in the treatment of neurologic disorders--has the future already arrived?]

<zakljucak> Buducnost celijske terapije u lecenju neuroloskih bolesti je pocela. Ostaju vazna pitanja na koja odgovor mogu dati samo dobro osmisljene medjunarodne studije, a ticu se vrste celija, nacina njihovog umnozavanja i aplikacije, kao i optimalnog vremenskog okvira za ovakvu vrstu lecenja.

Can we pass from the experimental to the clinical phase in MS stem cell research?

A crucial point in development of new treatments is the step from the experimental level to the first clinical trials. For stem cell treatments in general, but for stem cell treatment in Multiple Sclerosis specifically, this is the question for the moment. To answer this question a rational analysis of the hypotheses and the suppositions behind the application of stem cells is necessary, as well as a review of the present knowledge, the risks and the gains to be expected. This is a personal analysis of 32 oral presentation and discussions of the European Charcot Foundation Symposium, Taormina 2006. It is the application of the Kenter and Cohen [Kenter MJH, Cohen AF. Establishing risk of human experimentation with drugs: lessons from TGN 1412. Lancet 2006; 368:1387-91] approach, adapted for stem cell treatment in MS. About half of the pertinent issues plead for the start of clinical experiments now. However, the absence of knowledge on deleterious effects and their predictability heavily weights against it. Organisational and funding aspects were discussed to prevent uncritical, uncontrolled clinical approaches.

Bone marrow-derived stem cells in neurological diseases: stones or masons?

In spite of the commonly held belief that ‘the brain does not regenerate’, it is now accepted that postnatal neurogenesis does occur. Thus, one wonders whether cellular-replacement therapy might be used to heal the brain in diseases caused by neuronal cell loss. The existence of neural stem cells has been demonstrated by many scientists and is now generally accepted. The exact role of these cells, how their numbers are regulated and how they participate in CNS and spinal cord regeneration in postnatal life are still not well known. There are many reviews summarizing work on these cells; consequently, I will focus instead on other cells that may participate in postnatal neurogenesis: bone marrow-derived stem cells. The possibility that bone marrow-derived stem cells populate the CNS and differentiate into various neural elements is certainly not universally accepted.

Mammalian stem cells

Stem cells are quickly coming into focus of much biomedical research eventually aiming at the therapeutic applications for various disorders and trauma. It is important, however, to keep in mind the difference between the embryonic stem cells, somatic stem cells and somatic precursor cells when considering potential clinical applications. Here we provide the review of the current status of stem cell field and discuss the potential of therapeutic applications for blood and Immune system disorders, multiple sclerosis, hypoxic-ischemic brain injury and brain tumors. For the complimentary information about various stem cells and their properties we recommend consulting the National Institutes of Health stem cell resources (http://stemcells.nih.gov/info/basics).

Neurobehavioral aspects of cerebral white matter disorders

The study of higher function in humans requires a consideration of all the neural tissues in the brain. Long neglected as a contributor to the organization of cognitive and emotional operations, the cerebral white matter is now the subject of substantial effort to improve understanding. Among the many approaches that can address this area usefully, the study of individuals with white matter disorders offers a wealth of clinical insights that exploits the time-tested lesion method of behavioral neurology. This process is complemented by sophisticated neuroimaging techniques that increasingly enable detailed visualization of white matter tracts as they participate in the cognitive and emotional operations of distributed neural networks. In practical terms, an appreciation of the neurobehavioral importance of white matter disorders can be of great benefit for patients seen by neurologists and psychiatrists alike, especially because early recognition and treatment often can have an important influence on outcome. In theoretical terms, a focus on the white matter and its disorders promises to expand knowledge of the brain as an extraordinarily complex organ in which the connectivity provided by white matter is central to cognition, emotion, and consciousness itself. As the details of white matter structure and function become clarified, a more complete portrait of the organ of the mind can be anticipated.

Future directions in the treatment of Alzheimer’s disease

Alzheimer's disease (AD) remains the most common of the neurodegenerative disorders. In the elderly, it represents the most frequently occurring form of dementia, especially if considered alongside concomitant cerebrovascular disease. Current treatment involves the use of acetylcholinesterase inhibitors, which have shown symptomatic benefits in the recognised domains of cognition, function and behaviour. While they may have intrinsic disease-modifying activity, this is yet to be proven, and strategies to alter the fundamental neuropathological changes in AD continue to be sought. Much of the evidence suggests that the accumulation of amyloid-beta may play a pivotal role, therefore the bulk of current research is focused on possible intervention along the amyloid pathways. However, the abnormal phosphorylation of tau is also a reasonable target and as the molecular basis of AD is better delineated, more targeted treatment approaches are being proposed. This paper reports on the current data that is setting the future directions for research into AD.

Adult stem cells--reprogramming neurological repair?

Much excitement has surrounded recent breakthroughs in embryonic stem-cell research. Of lower profile, but no less exciting, are the advances in the field of adult stem-cell research, and their implications for cell therapy. Clinical experience from use of adult haemopoietic stem cells in haematology will facilitate and hasten transition from laboratory to clinic--indeed, clinical trials using adult human stem cells are already in progress in some disease states, including myocardial ischaemia. Here, with particular reference to neurology, we review processes that might underlie apparent changes in adult cell phenotype. We discuss implications these processes might have for the development of new therapeutic strategies using adult stem cells.