Drug-like delivery methods of stem cells as biologics for stroke

ABSTRACT

Introduction: Stem cell therapy is an experimental treatment for brain disorders. Although a cellular product, stem cells can be classified as biologics based on the cells’ secretion of therapeutic substances. Treatment with stem cell biologics may appeal to stroke because of the secondary cell death mechanisms, especially neuroinflammation, that are rampant from the onset and remain elevated during the progressive phase of the disease requiring multi-pronged biological targets to effectively abrogate the neurodegenerative pathology. However, the optimal delivery methods, among other logistical approaches (i.e. cell doses and timing of intervention), for stem cell therapy will need to be refined before stem cell biologics can be successfully utilized for stroke in large scale clinical trials.

Areas covered: In this review, we discuss how the innate qualities of stem cells characterize them as biologics, how stem cell transplantation may be an ideal treatment for stroke, and the various routes of stem cell administration that have been employed in various preclinical and clinical investigations.

Expert opinion: There is a need to optimize the delivery of stem cell biologics for stroke in order to guide the safe and effective translation of this therapy from the laboratory to the clinic.     

Embryonic stem cell therapy

Stem cell therapies, particularly those using embryonic stem cells, offer a novel approach to treating disease. There is an ongoing effort to develop tools and reagents to assist in understanding stem cells at a research level. In addition to these research tools, making stem cell therapy a reality requires the development of tools that enable the translation of research into viable therapies. Three sets of tools are discussed in this article: tools enabling stem cell scale-up and manufacture to GMP standards, tools addressing the behavior of cells in animal models, and tools to assess transplanted cells in early clinical trials. The development of such tools will address many of the safety and efficacy questions that are likely to arise as stem cell therapies move from bench to bedside.     

Design and creation of cytomedicine for application to cell therapy

Cells, which are the basic unit of life, are the most intelligent particles on earth. Recent advances in life science research encourage the development of cell therapy utilizing specialized functions of highly differentiated cells, the self-renewal and differentiation abilities of stem cells, and signal networks among various types of cells. Although cell therapy including ex vivo gene therapy, cellular immunotherapy, and regenerative therapy is expected to become the next generation of medical care for intractable disorders, the establishment of technology to prepare cells as medical supplies, namely, cytomedicine, is essential for the assurance of efficacy and safety in cell therapy. This review introduces our approach to the design and creation of cytomedicine for application to cell therapy against diabetes mellitus and cancer.     

Intranasal delivery of stem cells to the brain

INTRODUCTION: Stem cell-based therapy has proved to be a promising treatment option for neurological disorders. However, there are difficulties in successfully administrating these stem cells. For example, the brain-blood barrier impedes the entrance of stem cells into the CNS after systemic administration. Direct transplantation or injection may result in brain injury, and these strategies are clinically less feasible. Intranasal administration is a non-invasive and effective alternative for the delivery of drugs, vector-encoded viruses or even phages to the CNS. Recent studies have in fact demonstrated that stem cells may enter the CNS after intranasal administration. These results suggest that intranasal delivery may provide an alternative strategy for stem cell-based therapy. AREAS COVERED: This review summarizes current studies that have applied the intranasal delivery of stem cells into the brain. In addition, the distribution and fate of stem cells in the brain and the potential opportunities as well as challenges of intranasal stem cell delivery are also discussed. EXPERT OPINION: Intranasal delivery of stem cells is a new method with great potential for the transplantation of stem cells into the brain, and it may provide an extraordinary approach to overcoming the existing barriers of stem cell delivery for the treatment of many neurological disorders. This potential benefit emphasizes the importance of future research into intranasal delivery of stem cells.     

发展监管科学，促进细胞治疗产品和技术应用科学规范发展

细胞治疗（包括干细胞）是目前生物医药领域发展最快、最前沿的领域之一。细胞治疗产品是从实验室培养的干细胞、组织和器官中提取的,被注射到病人体内的生物技术产品。在分析国外情况的基础上,认为加强细胞产品制备和临床应用规范管理是势在必行的大事。提出细胞治疗产品和技术的监管科学的5大要素,据此分析了我国发展的3大短板。最后,为加强法规、政策与科学监管体系建设,促进细胞治疗产业和技术发展,提出发展细胞产品和技术应用的监管科学3点建议：一是发展细胞治疗监管科学的顶层设计的设想;二是在发展政策指导下,细胞产品研发体系和质量标准的原则是产业发展的基础和迫在眉睫的任务的问题;三是降低研发风险,明确细胞产品和治疗技术的主体责任。     

Preclinical pharmacology and safety of a novel avidin derivative for tissue-targeted delivery of radiolabelled biotin

Abstract: We recently described an oxidized avidin variant, named AvidinOX^®, which is a product that chemically links to tissue proteins while maintaining the capacity to uptake intravenously administered biotin. Such product proved to be successful in targeting radionuclide therapy in a mouse model of inoperable breast cancer. Here, we show that the uptake of a single or multiple doses of biotin (up to five times), by the tissue‐bound AvidinOX^®, is stable for 2 weeks. Taking into account that oxidized avidin is the first chemically reactive protein to be proposed for clinical use, we evaluated its tolerability, immunogenicity and mutagenicity. Present in vitro data indicate that AvidinOX^® (up to 10 μg/5 × 10⁵ cells) does not affect cell viability or proliferation of PC3 human prostate cancer or 3T3 mouse fibroblast cell lines as well as primary mouse spleen cells. Safety pharmacology and toxicology studies were conducted using AvidinOX^® up to the highest concentration compatible with its solubility (about 12 mg/mL), representing four times the product concentration intended for human use, and in the maximum administrable volume compatible with each study system. The intramuscular administration in rat and monkey induced a moderate to strong inflammatory response particularly after a second administration and consistently with the induction of an immune response. Interestingly, the intramuscular administration of AvidinOX^® to rodents and monkeys exhibiting very high anti‐avidin antibody titres was well tolerated with no systemic symptoms of any kind. Intravenous administration of AvidinOX^®, performed to mimic an accidental injection of the dose intended for a local administration (15 μL of 3.3 mg/mL solution), showed significant localization of the product into the spleen not associated with uptake of the radiolabelled biotin intravenously injected after 24 hr, thus suggesting rapid inactivation. No mutagenic activity was induced by oxidized avidin in prokaryotic and eukaryotic cells. Overall, the present data indicate that AvidinOX^® is well tolerated in rodents and non‐human primates, thus supporting its clinical use within protocols of radionuclide therapy of inoperable tumour lesions.     

Intranasal delivery of stem cells to the brain

Introduction: Stem cell-based therapy has proved to be a promising treatment option for neurological disorders. However, there are difficulties in successfully administrating these stem cells. For example, the brain–blood barrier impedes the entrance of stem cells into the CNS after systemic administration. Direct transplantation or injection may result in brain injury, and these strategies are clinically less feasible. Intranasal administration is a non-invasive and effective alternative for the delivery of drugs, vector-encoded viruses or even phages to the CNS. Recent studies have in fact demonstrated that stem cells may enter the CNS after intranasal administration. These results suggest that intranasal delivery may provide an alternative strategy for stem cell-based therapy.

Areas covered: This review summarizes current studies that have applied the intranasal delivery of stem cells into the brain. In addition, the distribution and fate of stem cells in the brain and the potential opportunities as well as challenges of intranasal stem cell delivery are also discussed.

Expert opinion: Intranasal delivery of stem cells is a new method with great potential for the transplantation of stem cells into the brain, and it may provide an extraordinary approach to overcoming the existing barriers of stem cell delivery for the treatment of many neurological disorders. This potential benefit emphasizes the importance of future research into intranasal delivery of stem cells.     

Dry Powder Antibiotic Aerosol Product Development: Inhaled Therapy for Tuberculosis

Inhaled therapies offer a unique approach to the treatment of tuberculosis (TB) using a relevant target organ system as a route of administration. The number of research reports on this topic has been increasing exponentially in the last decade but studies of clinical efficacy have been rare in recent times. The challenge is to take many research findings and translate them into a strategy for product development. Dry powder inhalers are the dominant drug product under consideration by those interested in the inhaled therapy for TB. A range of factors including candidate drug, formulation, device selection, drug product testing for proof of concept, and preclinical and clinical purposes all demand different considerations. The following review is intended to raise awareness of a growing body of evidence, suggesting that inhaled therapy for TB is possible and desirable. In addition, it is intended to outline key elements of the product‐development activity for this particular application that has not been discussed elsewhere in the literature. Hopefully, this will encourage those with development expertise to seriously contemplate the steps required to bring such products forward. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:3900–3907, 2013     

Rituximab in autologous stem cell transplantation for follicular lymphoma

Contamination of stem cell harvests with residual tumor cells is a significant problem hampering the success of autologous peripheral blood stem cell transplantation in non-Hodgkin's lymphoma (NHL). Techniques have therefore been introduced to attempt to remove these cells, either in vivo, prior to harvesting, or ex vivo, before reinfusion into the patient. Rituximab is a human-mouse chimeric anti-CD20 monoclonal antibody that has been administered to patients prior to stem cell harvesting, to purge the blood of residual malignant cells. Clinical studies have shown that rituximab is safe to use during stem cell mobilization since administration did not adversely affect the yield of CD34+ stem cells or the functional capability of these progenitors. Rituximab was also effective in purging stem cell harvests of malignant cells. Translocation of the bcl-2 gene was found in a significantly smaller proportion of stem cell harvests from patients who had received a purging infusion of rituximab than controls. Rituximab may also be useful as salvage therapy following post-transplant relapse or as maintenance therapy for patients in remission. Prospective randomized trials will ultimately define the role of rituximab in the autologous transplantation setting.     

Mesenchymal stem cells: a new trend for cell therapy

Mesenchymal stem cells (MSCs), the major stem cells for cell therapy, have been used in the clinic for approximately 10 years. From animal models to clinical trials, MSCs have afforded promise in the treatment of numerous diseases, mainly tissue injury and immune disorders. In this review, we summarize the recent opinions on methods, timing and cell sources for MSC administration in clinical applications, and provide an overview of mechanisms that are significant in MSC-mediated therapies. Although MSCs for cell therapy have been shown to be safe and effective, there are still challenges that need to be tackled before their wide application in the clinic.     

Bone marrow stem cell therapy for myocardial angiogenesis

Despite the recent advances in medical therapy and coronary revascularization procedures, coronary artery disease (CAD) remains the major cause of morbidity and mortality in the developing countries. In patients with severe CAD, persistent myocardial ischemia in hibernated myocardium resulted in progressive loss of cardiomyocytes with development of heart failure. As a result, therapeutic approaches to enhance neovascularization are being underwent intensive investigation. Recent experimental studies have demonstrated adult bone marrow (BM) can induce neovascularization in ischemic myocardium can improve heart function. These findings have prompted the development of different cellular transplantation approaches for heart diseases refractory to conventional therapy after myocardial infarction. Although the initial pilot clinical trials have shown potential clinical benefit of BM therapy for therapeutic angiogenesis, the long-term safety, the optimal timing and treatment strategy remains unclear. Furthermore, in order to acquire more optimized quality and quantity of BM derived stem cell for myocardial regeneration, several issues remain to be addressed, such as the development of a more efficient method of stem cells identification, purification and expansion. Emerging, rationally designed, randomized clinical trials are required to assess the clinical implication of BM derived stem cells therapy in treatment of CAD.     

系统性硬化症的细胞治疗进展

系统性硬化症(SSc)是一种病因不明的多系统结缔组织病,以皮肤和脏器进行性纤维化为特征.至今尚无能改变SSc自然病程的有效疗法.自造血干细胞移植治疗SSc取得突破性成绩以来,间充质干细胞、骨髓或脂肪来源干细胞、致耐受树突状细胞、调节性T细胞均被尝试用于SSc,但长期安全性和有效性尚有待进一步的临床验证.该文综述了现有的细胞治疗方法以评估其治疗SSc的潜力.     

New idea to promote the clinical applications of stem cells or their extracellular vesicles in central nervous system disorders: Combining with intranasal delivery

The clinical translation of stem cells and their extracellular vesicles (EVs)-based therapy for central nervous system (CNS) diseases is booming. Nevertheless, the insufficient CNS delivery and retention together with the invasiveness of current administration routes prevent stem cells or EVs from fully exerting their clinical therapeutic potential. Intranasal (IN) delivery is a possible strategy to solve problems as IN route could circumvent the brain‒blood barrier non-invasively and fit repeated dosage regimens. Herein, we gave an overview of studies and clinical trials involved with IN route and discussed the possibility of employing IN delivery to solve problems in stem cells or EVs-based therapy. We reviewed relevant researches that combining stem cells or EVs-based therapy with IN administration and analyzed benefits brought by IN route. Finally, we proposed possible suggestions to facilitate the development of IN delivery of stem cells or EVs.Key words: Stem cells, Extracellular vesicles, Central nervous system disorders, Intranasal, Clinical translation, Stroke, Neurodegenerative disease, Glioma     

Cell therapy for the treatment of chronic ischemic heart disease

Over the last decade, much was learned about the biology of several types of stem and progenitor cells. It has become apparent that various cell sources may have the capacity to promote cardiomyogenesis and new blood vessel formation through different mechanisms, forming the rationale for cell-based therapy in patients with chronic ischemic heart disease. After initial clinical studies have provided evidence for safety of cell administration, larger randomized trials demonstrated variable effects on myocardial perfusion and contractile performance. Although cell-based therapy is a promising strategy for the treatment of myocardial disease, many questions remain to be answered with respect to the optimal cell type, delivery route and mechanism of action in order to improve the outcome of cardiac cell therapy. This paper aims to provide an overview of the methods available to apply cell-based therapy in chronic ischemic myocardial disease. The different cell types that have been tested in (pre)clinical trials and their proposed mechanism of action will be discussed, along with the possible routes of cell delivery. Furthermore, the experience from experimental and clinical studies will be summarized, and innovative strategies to enhance the efficacy of cell therapy, for example by improving cell retention and survival, will be reviewed.     

Mesenchymal stem cells: cell biology and potential use in therapy

Mesenchymal stem cells are clonogenic, non-haematopoietic stem cells present in the bone marrow and are able to differentiate into multiple mesoderm-type cell lineages e.g. osteoblasts, chondrocytes, endothelial-cells and also non-mesoderm-type lineages e.g. neuronal-like cells. Several methods are currently available for isolation of the mesenchymal stem cells based on their physical and immunological characteristics. Because of the ease of their isolation and their extensive differentiation potential, mesenchymal stem cells are among the first stem cell types to be introduced in the clinic. Recent studies have demonstrated that the life span of mesenchymal stem cells in vitro can be extended by increasing the levels of telomerase expression in the cells and thus allowing culture of large number of cells needed for therapy. In addition, it has been shown that it is possible to culture the cells in xeno-free environment without affecting their growth or differentiation potential. Finally, the mesenchymal stem cells seems to be hypoimmunogenic and thus allogenic mesenchymal stem cells transplantation is possible. It is envisaged that mesenchymal stem cells can be used in systemic transplantation for generalized diseases, local implantation for local tissue defects, as a vehicle for genes in gene therapy protocols or to generate transplantable tissues and organs in tissue engineering protocols. The results of these initial trials are very encouraging and several clinical trials are under way to study the efficacy and long-term safety of therapeutics based on mesenchymal stem cells.     

干细胞临床研究及管理的现状与未来

干细胞研究和临床试验发展迅速,目前全球干细胞临床研究排名前三的国家或地区分别是美国、欧洲和中国,干细胞治疗种类以造血干细胞为主,间充质干细胞日益增长,神经干细胞和多能干细胞的临床试验也相对较多。目前全球已有14款干细胞药物上市,超过一半以上是间充质干细胞治疗产品。中国共有87个干细胞临床项目完成备案,其中间充质干细胞备案项目最多。细胞治疗是按照医疗技术还是药品来监管,世界各国有所不同。在美国按细胞组织类产品风险高低进行归类监管,欧盟以先进技术治疗医学产品归类监管,日本按照再生医学产品管理,中国目前进行机构和项目双备案制度。在严格分类管理的基础上,无论欧盟的医院豁免制度、日本的条件限制性准入政策,还是中国从药品-第三类医疗技术-备案制管理政策的变迁,都为干细胞及其他细胞治疗产品的研究和应用提供了科学而快速发展的政策保障。对国内外干细胞临床研究及应用的发展现状进行综述,同时分析各国干细胞临床研究相关的法律法规与质量控制监管政策。     

Stem cells as a treatment for chronic liver disease and diabetes

Advances in stem cell biology and the discovery of pluripotent stem cells have made the prospect of cell therapy and tissue regeneration a clinical reality. Cell therapies hold great promise to repair, restore, replace or regenerate affected organs and may perform better than any pharmacological or mechanical device. There is an accumulating body of evidence supporting the contribution of adult stem cells, in particular those of bone marrow origin, to liver and pancreatic islet cell regeneration. In this review, we will focus on the cell therapy for the diseased liver and pancreas by adult haematopoietic stem cells, as well as their possible contribution and application to tissue regeneration. Furthermore, recent progress in the generation, culture and targeted differentiation of human haematopoietic stem cells to hepatic and pancreatic lineages will be discussed. We will also explore the possibility that stem cell technology may lead to the development of clinical modalities for human liver disease and diabetes.     

Myocardial regeneration with stem cells: pharmacological possibilities for efficacy enhancement.

Cell therapy through the application of stem or progenitor cells to regenerate and repair damaged myocardium has gone from the bench to clinical trial. The functional benefits observed in clinical trials are, however, moderate, and many challenges need to be overcome before cell therapy can be put into widespread clinical use. Better understanding of the signals and molecules that promote cell proliferation, differentiation, engraftment and survival may lead to development of pharmacological agents that enhance the capacity of stem/progenitor cells for myocardial regeneration. The present review will provide a critical analysis of the merits and limitations of different populations of stem/progenitor cells and discuss the potential of pharmacological strategies for enhancing the efficacy of cell therapy for myocardial regeneration.     

Preclinical safety evaluation of human gene therapy products

Human gene therapy products include naked DNA and viral as well as non- viral vectors containing nucleic acids. There is limited experience on the preclinical toxicity studies necessary for the safety evaluation of these products, which have been outlined in several recently released guidelines. Requirements for the preclinical safety evaluation of human gene therapy products are both specific and non-specific. All key preclinical studies should be performed in compliance with Good Laboratory Practices. Non-specific requirements are in fact common to all pharmaceutical products. Critical specific issues to be addressed are: the safety evaluation of the vector and the toxicity of the expressed protein(s), which are the two components of gene therapy products, the quality of the test article, the selection of animal species, and the verification that the administration method successfully transports the gene of interest, with the vector, to the target site(s). The treatment schedule should mimic the intended human therapeutic design. The host's immune response against the gene therapy product has to be evaluated to detect possible adverse effects and immune neutralization by antibodies. The biodistribution of the gene of interest is also essential and can be evaluated by molecular biology techniques, such as PCR. Specific confinement is required for the safe manipulation of viral vectors.      

基因修饰体细胞国内外临床研究和相关产业现状及未来发展趋势

基因编辑技术可针对性增强体细胞的靶向性,一定程度上解决了传统过继性免疫疗法在肿瘤等多种疾病治疗中显露出的靶向性差等问题。最具代表性的是嵌合抗原受体T细胞(CAR-T)免疫疗法,其在血液系统肿瘤治疗中已取得良好疗效,此外,T细胞受体基因工程化的T细胞(TCR-T)、基因修饰的树突状细胞以及基因修饰的干细胞在多种疾病治疗的临床研究中也显现了良好的安全性和有效性。目前国内外多家研究机构和生物公司已在基因修饰体细胞行业加速布局,相关产业即将进入快速发展期,基因修饰体细胞疗法的临床转化应用具有广阔前景,对目前已经开展疾病临床研究的几种基因修饰免疫细胞疗法进行总结。