Isolation, Culture, and Functional Characterization of Human Embryonic Stem Cells: Current Trends and Challenges

The Current Update of Conventional and Innovative Treatment Strategies for Central Nervous System Injury

This review explores the complex challenges and advancements in the treatment of traumatic brain injury (TBI) and spinal cord injury (SCI). Traumatic injuries to the central nervous system (CNS) trigger intricate pathophysiological responses, frequently leading to profound and enduring disabilities. This article delves into the dual phases of injury-primary impacts and the subsequent secondary biochemical cascades-that worsen initial damage. Conventional treatments have traditionally prioritized immediate stabilization, surgical interventions, and supportive medical care to manage both the primary and secondary damage associated with central nervous system injuries. We explore current surgical and medical management strategies, emphasizing the crucial role of rehabilitation and the promising potential of stem cell therapies and immune modulation. Advances in stem cell therapy, gene editing, and neuroprosthetics are revolutionizing treatment approaches, providing opportunities not just for recovery but also for the regeneration of impaired neural tissues. This review aims to emphasize emerging therapeutic strategies that hold promise for enhancing outcomes and improving the quality of life for affected individuals worldwide.

Stem Cells and Acellular Preparations in Bone Regeneration/Fracture Healing: Current Therapies and Future Directions

Bone/fracture healing is a complex process with different steps and four basic tissue layers being affected: cortical bone, periosteum, fascial tissue surrounding the fracture, and bone marrow. Stem cells and their derivatives, including embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, hematopoietic stem cells, skeletal stem cells, and multipotent stem cells, can function to artificially introduce highly regenerative cells into decrepit biological tissues and augment the healing process at the tissue level. Stem cells are molecularly and functionally indistinguishable from standard human tissues. The widespread appeal of stem cell therapy lies in its potential benefits as a therapeutic technology that, if harnessed, can be applied in clinical settings. This review aims to establish the molecular pathophysiology of bone healing and the current stem cell interventions that disrupt or augment the bone healing process and, finally, considers the future direction/therapeutic options related to stem cells and bone healing.

Standardisation is the key to the sustained, rapid and healthy development of stem cell-based therapy

BACKGROUND

Stem cell-based therapy (SCT) is an important component of regenerative therapy that brings hope to many patients. After decades of development, SCT has made significant progress in the research of various diseases, and the market size has also expanded significantly. The transition of SCT from small-scale, customized experiments to routine clinical practice requires the assistance of standards. Many countries and international organizations around the world have developed corresponding SCT standards, which have effectively promoted the further development of the SCT industry.

METHODS

We conducted a comprehensive literature review to introduce the clinical application progress of SCT and focus on the development status of SCT standardization.

RESULTS

We first briefly introduced the types and characteristics of stem cells, and summarized the current clinical application and market development of SCT. Subsequently, we focused on the development status of SCT-related standards as of now from three levels: the International Organization for Standardization (ISO), important international organizations, and national organizations. Finally, we provided perspectives and conclusions on the significance and challenges of SCT standardization.

CONCLUSIONS

Standardization plays an important role in the sustained, rapid and healthy development of SCT.

Comparing stem cells, transdifferentiation and brain organoids as tools for psychiatric research

The inaccessibility of neurons coming directly from patients has hindered our understanding of mental illnesses at the cellular level. To overcome this obstacle, six different cellular approaches that carry the genetic vulnerability to psychiatric disorders are currently available: Olfactory Neuroepithelial Cells, Mesenchymal Stem Cells, Pluripotent Monocytes, Induced Pluripotent Stem Cells, Induced Neuronal cells and more recently Brain Organoids. Here we contrast advantages and disadvantages of each of these six cell-based methodologies. Neuronal-like cells derived from pluripotent monocytes are presented in more detail as this technique was recently used in psychiatry for the first time. Among the parameters used for comparison are; accessibility, need for reprograming, time to deliver differentiated cells, differentiation efficiency, reproducibility of results and cost. We provide a timeline on the discovery of these cell-based methodologies, but, our main goal is to assist researchers selecting which cellular approach is best suited for any given project. This manuscript also aims to help readers better interpret results from the published literature. With this goal in mind, we end our work with a discussion about the differences and similarities between cell-based techniques and postmortem research, the only currently available tools that allow the study of mental illness in neurons or neuronal-like cells coming directly from patients.

Stem cell-based combinatorial therapies for spinal cord injury: a narrative review of current research and future directions

Spinal cord injury (SCI) is a devastating condition that can result in lifelong disability. Despite significant progress in SCI research, current treatments only offer limited functional recovery. Stem cell-based combinatorial therapies have emerged promising to enhance neural repair and regeneration after SCI. Combining stem cells with growth factors, biomaterials, and other therapeutic agents can improve outcomes by providing a multifaceted approach to neural repair. However, several challenges must be addressed before these therapies can be widely adopted in clinical practice. Standardisation of stem cell isolation, characterisation, and production protocols ensures consistency and safety in clinical trials. Developing appropriate animal models that accurately mimic human SCI is crucial for successfully translating these therapies. Additionally, optimal delivery methods and biomaterials that support the survival and integration of stem cells into injured tissue must be identified. Despite these challenges, stem cell-based combinatorial therapies for SCI hold great promise. Innovative approaches such as gene editing and the use of neural tissue engineering may further enhance the efficacy of these therapies. Further research and development in this area are critical to advancing the field and providing effective therapies for SCI patients. This paper discusses the current evidence and challenges from the literature on the potential of stem cell-based combinatorial therapies for SCI.

Stem Cells and the Microenvironment: Reciprocity with Asymmetry in Regenerative Medicine

Much of the current research in regenerative medicine concentrates on stem-cell therapy that exploits the regenerative capacities of stem cells when injected into different types of human tissues. Although new therapeutic paths have been opened up by induced pluripotent cells and human mesenchymal cells, the rate of success is still low and mainly due to the difficulties of managing cell proliferation and differentiation, giving rise to non-controlled stem cell differentiation that ultimately leads to cancer. Despite being still far from becoming a reality, these studies highlight the role of physical and biological constraints (e.g., cues and morphogenetic fields) placed by tissue microenvironment on stem cell fate. This asks for a clarification of the coupling of stem cells and microenvironmental factors in regenerative medicine. We argue that extracellular matrix and stem cells have a causal reciprocal and asymmetric relationship in that the 3D organization and composition of the extracellular matrix establish a spatial, temporal, and mechanical control over the fate of stem cells, which enable them to interact and control (as well as be controlled by) the cellular components and soluble factors of microenvironment. Such an account clarifies the notions of stemness and stem cell regeneration consistently with that of microenvironment.

Expression of Zeb1 in the differentiation of mouse embryonic stem cell

Embryonic stem cells (ESCs) differentiation is a process of replication and refinement, and the directional lineage differentiation of ESCs involves the epithelial-mesenchymal transition (EMT)- mesenchymal-epithelial transition (MET) process. A previous study revealed that Zinc finger E-box-binding homeobox 1 (Zeb1) plays a vital role in EMT, which could repress E-cadherin promoter and induce an EMT in cells. To verify the expression of Zeb1 and its correlation with Lin28a in mouse ESCs differentiation, we performed qRT-PCR and western blots to detect the expression of Lin28a mRNA and protein after Zeb1 knockdown. The expression of Zeb1 decreased over time of mouse ESCs differentiation but significantly increased in mouse embryonal carcinoma cells. After knockdown of Zeb1, Lin28a and Vimentin expression were decreased, while E-cadherin expression increased both in mouse ESCs, EBs, GC1, and P19 cells. We found that Zeb1 promoted the invasive ability of mouse embryonal carcinoma cells. These results revealed that expression of Zeb1 decreased during the differentiation of ESCs, and Lin28a and EMT processes can be regulated by Zeb1, which need to be verified in the future studies.

DDX4 + stem cells in the ovaries of postmenopausal women: existence and differentiation potential

Ovarian aging is a pacemaker with multiple organ dysfunction. Recently, stem cells with the ability to generate new oocytes have been identified, which provides the possibility of stem cell therapy for ovarian aging. Several studies have revealed the existence of stem cells in human postmenopausal ovary. In this study, we describe a new method using magnetic activated cell sorting combined with differential adhesion to isolate DDX4 + stem cells from ovaries of postmenopausal women and show that the cells exhibit similar gene expression profiles and growth characteristics with primitive germ cells. Furthermore, the DDX4 + stem cells could enter meiosis stage and differentiation into oocytes. The RNA-seq data of the differentiated oocytes shows that mitochondrial metabolism may play an important role in the oogenesis process of the DDX4 + stem cells. Through using human ovarian cortical fragments transplantation model, we indicated that the GFP-DDX4 + stem cells differentiated into some GFP positive oocyte-like structure in vivo. Our study provided a new method for the isolation of DDX4 + stem cells from the ovaries of postmenopausal women and confirmed the ability of these stem cells to differentiate into oocytes.

Diamond Concept as Principle for the Development of Spinal Cord Scaffold: A Literature Review

INTRODUCTION: Spinal cord injury (SCI) has been bringing detrimental impacts on the affected individuals. However, not only that, it also brings a tremendous effect on the socioeconomic and health-care system. Treatment regimen and strategy for SCI patient have been under further research. DISCUSSION: The main obstacles of regeneration on neuronal structure are the neuroinflammatory process and poor debris clearance, causing a longer healing process and an extensive inflammation process due to this particular inflammatory process. To resolve all of the mentioned significant issues in SCIs neuronal regeneration, a comprehensive model is necessary to analyze each step of progressive condition in SCI. In this review, we would like to redefine a comprehensive concept of the “Diamond Concept” from previously used in fracture management to SCI management, which consists of cellular platform, cellular inductivity, cellular conductivity, and material integrity. The scaffolding treatment strategy for SCI has been widely proposed due to its flexibility. It enables the physician to combine another treatment method such as neuroprotective or neuroregenerative or both in one intervention. CONCLUSION: Diamond concept perspective in the implementation of scaffolding could be advantageous to increase the outcome of SCI treatment.

Clinical Practice of Umbilical Cord Blood Stem Cells in Transplantation and Regenerative Medicine - Prodigious Promise for Imminent Times

The umbilical cord blood is usually disposed of as an unwanted material after parturition; however, today, it is viewed as a regenerative medication so as to create the organ tissues. This cord blood gathered from the umbilical cord is made up of mesenchymal stem cells, hematopoietic stem cells, and multipotent non-hematopoietic stem cells having many therapeutic effects as these stem cells are utilized to treat malignancies, hematological ailments, inborn metabolic problem, and immune deficiencies. Presently, numerous clinical applications for human umbilical cord blood inferred stem cells, as stem cell treatment initiate new research. These cells are showing such a boon to stem cell treatment; it is nevertheless characteristic that the prospect of conservation of umbilical cord blood is gaining impetus. Current research works have demonstrated that about 80 diseases, including cancer, can be treated or relieved utilizing umbilical cord blood stem cells, and every year, many transplants have been effectively done around the world. However, in terms of factors, including patient selection, cell preparation, dosing, and delivery process, the treatment procedure for therapy with minimally manipulated stem cells can be patented. It is also worth thinking about how this patent could affect cord blood banks. Meanwhile, the utilization of cord blood cells is controversial and adult-derived cells may not be as successful, so numerous clinicians have begun working with stem cells that are acquired from umbilical cord blood. This review epitomizes a change in outlook from what has been completed with umbilical cord blood cell research and cord blood banking on the grounds that cord blood cells do not require much in the method of handling for cryopreservation or for transplantation in regenerative medicine.

Human Pluripotent Stem Cells in Neurodegenerative Diseases: Potentials, Advances and Limitations

Neurodegenerative diseases are progressive and uncontrolled gradual loss of motor neurons function or death of neuron cells in the central nervous system (CNS) and the mechanisms underlying their progressive nature remain elusive. There is urgent need to investigate therapeutic strategies and novel treatments for neural regeneration in disorders like Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS). Currently, the development and identification of pluripotent stem cells enabling the acquisition of a large number of neural cells in order to improve cell recovery after neurodegenerative disorders. Pluripotent stem cells which consist of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are characterized by their ability to indefinitely self-renew and the capacity to differentiate into different types of cells. The first human ESC lines were established from donated human embryos; while, because of a limited supply of donor embryos, human ESCs derivation remains ethically and politically controversial. Hence, hiPSCs-based therapies have been shown as an effective replacement for human ESCs without embryo destruction. Compared to the invasive methods for derivation of human ESCs, human iPSCs has opened possible to reprogram patient-specific cells by defined factors and with minimally invasive procedures. Human pluripotent stem cells are a good source for cell-based research, cell replacement therapies and disease modeling. To date, hundreds of human ESC and human iPSC lines have been generated with the aim of treating various neurodegenerative diseases. In this review, we have highlighted the recent potentials, advances, and limitations of human pluripotent stem cells for the treatment of neurodegenerative disorders.

Optogenetically Controlled TrkA Activity Improves the Regenerative Capacity of Hair-Follicle-Derived Stem Cells to Differentiate into Neurons and Glia

Hair-follicle-derived stem cells (HSCs) originating from the bulge region of the mouse vibrissa hair follicle are able to differentiate into neuronal and glial lineage cells. The tropomyosin receptor kinase A (TrkA) receptor that is expressed on these cells plays key roles in mediating the survival and differentiation of neural progenitors as well as in the regulation of the growth and regeneration of different neural systems. In this study, the OptoTrkA system is introduced, which is able to stimulate TrkA activity via blue-light illumination in HSCs. This allows to determine whether TrkA signaling is capable of influencing the proliferation, migration, and neural differentiation of these somatic stem cells. It is found that OptoTrkA is able to activate downstream molecules such as ERK and AKT with blue-light illumination, and subsequently able to terminate this kinase activity in the dark. HSCs with OptoTrkA activity show an increased ability for proliferation and migration and also exhibited accelerated neuronal and glial cell differentiation. These findings suggest that the precise control of TrkA activity using optogenetic tools is a viable strategy for the regeneration of neurons from HSCs, and also provides a novel insight into the clinical application of optogenetic tools in cell-transplantation therapy.

Stem Cell Aging and Regenerative Medicine

Stem cells are a promising source for regenerative medicine to cure a plethora of diseases that are currently treated based on either palliative or symptomatic relief or by preventing their onset and progression. Aging-associated degenerative changes in stem cells, stem cell niches, and signaling pathways bring a step by step decline in the regenerative and functional potential of tissues. Clinical studies and experiments on model organisms have pointed out checkpoints that aging will inevitably impose on stem cell aiming for transplantation and hence questions are raised about the age of the donor. In the following discourse, we review the fundamental molecular pathways that are implicated in stem cell aging and the current progress in tissue engineering and transplantation of each type of stem cells in regenerative medicine. We further focus on the consequences of stem cell aging on their clinical uses and the development of novel strategies to bypass those pitfalls and improve tissue replenishment.

Adult Stem Cells for Bone Regeneration and Repair

The regeneration of bone fractures, resulting from trauma, osteoporosis or tumors, is a major problem in our super-aging society. Bone regeneration is one of the main topics of concern in regenerative medicine. In recent years, stem cells have been employed in regenerative medicine with interesting results due to their self-renewal and differentiation capacity. Moreover, stem cells are able to secrete bioactive molecules and regulate the behavior of other cells in different host tissues. Bone regeneration process may improve effectively and rapidly when stem cells are used. To this purpose, stem cells are often employed with biomaterials/scaffolds and growth factors to accelerate bone healing at the fracture site. Briefly, this review will describe bone structure and the osteogenic differentiation of stem cells. In addition, the role of mesenchymal stem cells for bone repair/regrowth in the tissue engineering field and their recent progress in clinical applications will be discussed.

Dental Pulp Stem Cell-Derived Factors Alleviate Subarachnoid Hemorrhage-Induced Neuroinflammation and Ischemic Neurological Deficits

Aneurysmal subarachnoid hemorrhage (aSAH), characterized by the extravasation of blood into the subarachnoid space caused by an intracranial aneurysm rupture, may lead to neurocognitive impairments and permanent disability and usually carries poor outcome. Dental or gingiva-derived stem cells have been shown to contribute to immune modulation and neuroregeneration, but the underlying mechanisms are unclear. In the present study, we sought to investigate whether dental pulp stem cells (DPSCs) secrete certain factor(s) that can ameliorate the neural damage and other manifestations in a rat aSAH model. Twenty-four hours after the induction of aSAH, microthrombosis, cortical vasoconstriction, and the decrease in microcirculation and tissue oxygen pressure were detected. Intrathecal administration of DPSC-derived conditioned media (DPSC-CM) ameliorated aSAH-induced vasoconstriction, neuroinflammation, and improved the oxygenation in the injured brain. Rotarod test revealed that the aSAH-induced cognitive and motor impairments were significantly improved by this DPSC-CM administration. Cytokine array indicated the major constituent of DPSC-CM was predominantly insulin growth factor-1 (IGF-1). Immunohistochemistry staining of injured brain tissue revealed the robust increase in Iba1-positive cells that were also ameliorated by DPSC-CM administration. Antibody-mediated neutralization of IGF-1 moderately deteriorated the rescuing effect of DPSC-CM on microcirculation, Iba1-positive cells in the injured brain area, and the cognitive/motor impairments. Taken together, the DPSC-derived secretory factors showed prominent therapeutic potential for aSAH. This therapeutic efficacy may include improvement of microcirculation, alleviation of neuroinflammation, and microglial activation; partially through IGF-1-dependent mechanisms.

Ethics assessment in research proposals adopting CRISPR technology

The rapid and exponential growth of genome editing has posed many challenges for bioethics. This article briefly explains the nature of the technique and the particularly rapid development of Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) technology. The international and, specifically, European-level systems for assessing the ethical issues consequent on these developments are outlined and discussed. The challenges posed by cases in China are summarized to raise concerns about how a more shared, universally consistent appraisal of bioethical issues can be promoted.