Adult Stem Cells for Regenerative Therapy

Autologous Stem Cell Transplant in Hodgkin's and Non-Hodgkin's Lymphoma, Multiple Myeloma, and AL Amyloidosis

Human body cells are stem cell (SC) derivatives originating from bone marrow. Their special characteristics include their capacity to support the formation and self-repair of the cells. Cancer cells multiply uncontrollably and invade healthy tissues, making stem cell transplants a viable option for cancer patients undergoing high-dose chemotherapy (HDC). When chemotherapy is used at very high doses to eradicate all cancer cells from aggressive tumors, blood-forming cells and leukocytes are either completely or partially destroyed. Autologous stem cell transplantation (ASCT) is necessary for patients in those circumstances. The patients who undergo autologous transplants receive their own stem cells (SCs). The transplanted stem cells first come into contact with the bone marrow and then undergo engraftment, before differentiating into blood cells. ASCT is one of the most significant and innovative strategies for treating diseases. Here we focus on the treatment of Hodgkin's lymphoma, non-Hodgkin's lymphoma, multiple myeloma, and AL amyloidosis, using ASCT. This review provides a comprehensive picture of the effectiveness and the safety of ASCT as a therapeutic approach for these diseases, based on the currently available evidence.

The Safety and Efficacy of Human Umbilical Cord-Derived Mesenchymal Stem Cells in Patients With Heart Failure and Myocardial Infarction: A Meta-Analysis of Clinical Trials

Evidence from preclinical and clinical studies suggests that human umbilical cord-derived mesenchymal stromal cells (HUC-MSCs) may be useful in treating heart failure and acute myocardial infarction (MI). However, the effects of stem cell therapy on patients with heart failure remain the subject of ongoing controversy, and the safety and effectiveness of HUC-MSCs therapy have not yet been proven. To date, there has been no systematic overview and meta-analysis of clinical studies using HUC-MSCs therapy for heart failure and MI. The purpose of this study is to assess the safety and efficacy of HUC-MSC therapy versus a placebo in patients with heart failure and MI. While preparing this systematic review and meta-analysis, we adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A computer literature search of PubMed was performed. We considered randomized controlled trials (RCTs) that reported data on the safety and efficacy of HUC-MSC transplantation in patients with heart failure and MI. Two investigators independently searched the literature, extracted data, and rated the quality of the included research. Pooled data were analyzed using the fixed-effect model or the random-effect model in Review Manager 5.3. The Cochrane risk of bias tool was used to assess the bias of included studies. The primary outcome was ejection fraction (EF), whereas the secondary outcomes were readmission and mortality rates. Three RCTs (201 patients) were included in this meta-analysis. The overall effect did not favor either of the two groups in terms of risk of readmission (risk ratio = 0.5, 95% confidence interval (CI) = 0.22-1.15, p = 0.10) as well as mortality rate (risk ratio = 0.44, 95% CI = 0.14-1.44, p = 0.18). However, there was an improvement in EF in patients who received HUC-MSCs compared to placebo after 12 months of transplantation (mean difference (MD) = 3.21, 95% CI = 2.91-3.51, p < 0.00001). At the six-month follow-up period, there was no significant improvement in EF (MD = 1.30, 95% CI = -1.94-4.54), p = 0.43), indicating that the duration of follow-up can shape the response to therapy. Our findings indicate that HUC-MSC transplantation can improve EF but has no meaningful effect on readmission or mortality rates. Existing evidence is insufficient to confirm the efficacy of HUC-MSCs for broader therapeutic applications. Therefore, additional double-blind RCTs with larger sample sizes are required.

Insight into the Potential Mechanisms of Endocrine Disruption by Dietary Phytoestrogens in the Context of the Etiopathogenesis of Endometriosis

Phytoestrogens (PEs) are estrogen-like nonsteroidal compounds derived from plants (e.g., nuts, seeds, fruits, and vegetables) and fungi that are structurally similar to 17β-estradiol. PEs bind to all types of estrogen receptors, including ERα and ERβ receptors, nuclear receptors, and a membrane-bound estrogen receptor known as the G protein-coupled estrogen receptor (GPER). As endocrine-disrupting chemicals (EDCs) with pro- or antiestrogenic properties, PEs can potentially disrupt the hormonal regulation of homeostasis, resulting in developmental and reproductive abnormalities. However, a lack of PEs in the diet does not result in the development of deficiency symptoms. To properly assess the benefits and risks associated with the use of a PE-rich diet, it is necessary to distinguish between endocrine disruption (endocrine-mediated adverse effects) and nonspecific effects on the endocrine system. Endometriosis is an estrogen-dependent disease of unknown etiopathogenesis, in which tissue similar to the lining of the uterus (the endometrium) grows outside of the uterus with subsequent complications being manifested as a result of local inflammatory reactions. Endometriosis affects 10-15% of women of reproductive age and is associated with chronic pelvic pain, dysmenorrhea, dyspareunia, and infertility. In this review, the endocrine-disruptive actions of PEs are reviewed in the context of endometriosis to determine whether a PE-rich diet has a positive or negative effect on the risk and course of endometriosis.

Ginsenosides on stem cells fate specification-a novel perspective

Recent studies have demonstrated that stem cells have attracted much attention due to their special abilities of proliferation, differentiation and self-renewal, and are of great significance in regenerative medicine and anti-aging research. Hence, finding natural medicines that intervene the fate specification of stem cells has become a priority. Ginsenosides, the key components of natural botanical ginseng, have been extensively studied for versatile effects, such as regulating stem cells function and resisting aging. This review aims to summarize recent progression regarding the impact of ginsenosides on the behavior of adult stem cells, particularly from the perspective of proliferation, differentiation and self-renewal.

Decellularized Extracellular Matrix: The Role of This Complex Biomaterial in Regeneration

Organ transplantation is understood as a technique where an organ from a donor patient is transferred to a recipient patient. This practice gained strength in the 20th century and ensured advances in areas of knowledge such as immunology and tissue engineering. The main problems that comprise the practice of transplants involve the demand for viable organs and immunological aspects related to organ rejection. In this review, we address advances in tissue engineering for reversing the current challenges of transplants, focusing on the possible use of decellularized tissues in tissue engineering. We address the interaction of acellular tissues with immune cells, especially macrophages and stem cells, due to their potential use in regenerative medicine. Our goal is to exhibit data that demonstrate the use of decellularized tissues as alternative biomaterials that can be applied clinically as partial or complete organ substitutes.

Clinical Evaluation of Conditioned Media of Human Umbilical Cord Blood Mesenchymal Stem Cells for Improvement of Symptoms of Sensitive Skin: Prospective, Single Blinded, Split-face Study

BACKGROUND

The exact definition of sensitive skin is not established yet. Since its high prevalence and significant influence on quality of life, it has become an important topic of research. Among various ingredients, conditioned media from umbilical cord blood-derived mesenchymal stem cells (UCB-MSC-CM) can be a promising source for the treatment of sensitive skin.

OBJECTIVE

We evaluated the efficacy and safety of UCB-MSC-CM on patients with sensitive skin.

METHODS

We designed a randomized, single blinded, prospective, split-face comparison study and enrolled thirty patients. All patients underwent nonablative fractional laser over the entire face before UCB-MSC-CM or normal saline was applied. Each facial area was randomly assigned to undergo treatment with either UCB-MSC-CM or normal saline. We performed three sessions at two-week intervals, and final results were assessed on six weeks after the last session. As an outcome measure, we evaluated a five-point global assessment scale, transepidermal water loss (TEWL), erythema index (EI) and Sensitive Scale-10. Twenty seven subjects were included in final analysis.

RESULTS

The treated side exhibited greater improvement compared to the untreated side based on a five-point global assessment scale. TEWL, EI of the treated side were significantly lower than those of the untreated side throughout study period. Sensitive Scale-10 was significantly improved after treatment.

CONCLUSION

The application of UCB-MSC-CM resulted in improved skin barrier function and reduced inflammatory responsiveness, which could provide beneficial effect on sensitive skin.

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.

Bone marrow derived mesenchymal stem cells therapy for rheumatoid arthritis - a concise review of past ten years

Rheumatoid arthritis is an autoimmune disorder characterized by swelling in synovial joints and erosion of bones. The disease is normally treated with conventional drugs which provide only temporary relief to the symptoms. Over the past few years, mesenchymal stromal cells have become the center of attention for treating this disease due to their immuno-modulatory and anti-inflammatory characteristics. Various studies on treatment of rheumatoid arthritis by using these cells have shown positive outcomes in terms of reduction in the level of pain as well as improvement of the function and structure of joints. Mesenchymal stromal cells can be derived from multiple sources, however, the ones derived from bone marrow are considered most beneficial for treating several disorders including rheumatoid arthritis on account of being safer and more effective. This review summarizes all the preclinical and clinical studies which were conducted over the last ten years for therapy of rheumatoid arthritis utilizing these cells. The literature was reviewed using the terms "mesenchymal stem/stromal cells and rheumatoid arthritis'' and "bone marrow derived mesenchymal stromal cells and therapy of rheumatoid arthritis''. Data was extracted to enable the readers to have access to the most relevant information regarding advancement in therapeutic potential of these stromal cells. Additionally, this review will also help in fulfilling any gap in current knowledge of readers about the outcome of using these cells in animal models, cell line and in patients suffering from rheumatoid arthritis and other autoimmune disorders as well.

Aberrant epigenetic regulation of estrogen and progesterone signaling at the level of endometrial/endometriotic tissue in the pathomechanism of endometriosis

Endometriosis is a term referring to a condition whereby the endometrial tissue is found outside the uterine cavity. This progressive and debilitating condition affects up to 15% of women of reproductive age. Due to the fact that endometriosis cells may express estrogen receptors (ERα, Erβ, GPER) and progesterone (P4) receptors (PR-A, PR-B), their growth, cyclic proliferation, and breakdown are similar to the processes occurring in the endometrium. The underlying etiology and pathogenesis of endometriosis are still not fully explained. The retrograde transport of viable menstrual endometrial cells with the retained ability to attach within the pelvic cavity, proliferate, differentiate and invade into the surrounding tissue explains the most widely accepted implantation theory. Endometrial stromal cells (EnSCs) with clonogenic potential constitute the most abundant population of cells within endometrium that resemble the properties of mesenchymal stem cells (MSCs). Accordingly, formation of the endometriotic foci in endometriosis may be due to a kind of EnSCs dysfunction. Increasing evidence indicates the underestimated role of epigenetic mechanisms in the pathogenesis of endometriosis. Hormone-mediated epigenetic modifications of the genome in EnSCs or even MSCs were attributed an important role in the etiopathogenesis of endometriosis. The roles of excess estrogen exposure and P4 resistance were also found to be crucial in the development of epigenetic homeostasis failure. Therefore, the aim of this review was to consolidate the current knowledge regarding the epigenetic background of EnSCs and MSCs and the changed properties due to estrogen/P4 imbalances in the context of the etiopathogenesis of endometriosis.

Engineered adult stem cells: a promising tool for anti-cancer therapy

Cancers are one of the most dreaded diseases in human history and have been targeted by numerous trials including surgery, chemotherapy, radiation therapy, and anti-cancer drugs. Adult stem cells (ASCs), which can regenerate tissues and repair damage, have emerged as leading therapeutic candidates due to their homing ability toward tumor foci. Stem cells can precisely target malicious tumors, thereby minimizing the toxicity of normal cells and unfavorable side effects. ASCs, such as mesenchymal stem cells (MSCs), neural stem cells (NSCs), and hematopoietic stem cells (HSCs), are powerful tools for delivering therapeutic agents to various primary and metastatic cancers. Engineered ASCs act as a bridge between the tumor sites and tumoricidal reagents, producing therapeutic substances such as exosomes, viruses, and anti-cancer proteins encoded by several suicide genes. This review focuses on various anti-cancer therapies implemented via ASCs and summarizes the recent treatment progress and shortcomings. [BMB Reports 2023; 56(2): 71-77].

Engineered adult stem cells: a promising tool for anti-cancer therapy

Cancers are one of the most dreaded diseases in human history and have been targeted by numerous trials including surgery, chemotherapy, radiation therapy, and anti-cancer drugs. Adult stem cells (ASCs), which can regenerate tissues and repair damage, have emerged as leading therapeutic candidates due to their homing ability toward tumor foci. Stem cells can precisely target malicious tumors, thereby minimizing the toxicity of normal cells and unfavorable side effects. ASCs, such as mesenchymal stem cells (MSCs), neural stem cells (NSCs), and hematopoietic stem cells (HSCs), are powerful tools for delivering therapeutic agents to various primary and metastatic cancers. Engineered ASCs act as a bridge between the tumor sites and tumoricidal reagents, producing therapeutic substances such as exosomes, viruses, and anti-cancer proteins encoded by several suicide genes. This review focuses on various anti-cancer therapies implemented via ASCs and summarizes the recent treatment progress and shortcomings. [BMB Reports 2023; 56(2): 71-77].

Advances in Neural Stem Cell Therapy for Spinal Cord Injury: Safety, Efficacy, and Future Perspectives

Spinal cord injury (SCI) is a devastating central nervous system injury that leads to severe disabilities in motor and sensory functions, causing significant deterioration in patients' quality of life. Owing to the complexity of SCI pathophysiology, there has been no effective treatment for reversing neural tissue damage and recovering neurological functions. Several novel therapies targeting different stages of pathophysiological mechanisms of SCI have been developed. Among these, treatments using stem cells have great potential for the regeneration of damaged neural tissues. In this review, we have summarized recent preclinical and clinical studies focusing on neural stem cells (NSCs). NSCs are multipotent cells with specific differentiation capabilities for neural lineage. Several preclinical studies have demonstrated the regenerative effects of transplanted NSCs in SCI animal models through both paracrine effects and direct neuronal differentiation, restoring synaptic connectivity and neural networks. Based on the positive results of several preclinical studies, phase I and II clinical trials using NSCs have been performed. Despite several hurdles and issues that need to be addressed in the clinical use of NSCs in patients with SCI, gradual progress in the technical development and therapeutic efficacy of NSCs treatments has enhanced the prospects for cell-based treatments in SCI.

Intermittent hypoxic conditioning restores neurological dysfunction of mice induced by long-term hypoxia

BACKGROUND

Central nervous system diseases are associated with hypoxia, which usually cause irreversible nerve damage, but the underlying mechanism is unclear and effective intervention strategies are lacking. This study was designed to explore the mechanism and treatment strategy of hypoxia-induced nerve injury.

METHODS

In this study, 13% O₂ was used to treat mice for 0, 1, 3 7, and 14 days, Morris water maze and other animal behavior experiments were used to evaluate the neurological function of mice. TUNEL, BrdU, PCNA, DCX, and SOX2 staining were used to observe the apoptosis and proliferation of mouse neurons. RT-PCR and Iba1 staining were used to evaluate the release of inflammatory factors IL-1β, IL-6, and TNF-α and the activation of microglia.

RESULTS

Short-term hypoxia promotes neurogenesis, while long-term hypoxia inhibits neurogenesis. The changes in hypoxia-induced neurogenesis were positively correlated with neurological functions, but negatively correlated with apoptosis. Moreover, intermittent hypoxic conditioning restored long-term hypoxia-induced neurological dysfunction by promoting neural stem cell generation and inhibiting the release of inflammatory factors IL-1β, IL-6, and TNF-α and the activation of microglia.

CONCLUSION

Hypoxia promoted neurogenesis in a time-dependent manner, and intermittent hypoxic conditioning exerted a neuroprotective effect through promoting neural stem cell generation and suppressing inflammation induced by long-term hypoxia stress, which provided a novel concept to develop a treatment for hypoxia-related brain injury.

Skewed fate and hematopoiesis of CD34(+) HSPCs in umbilical cord blood amid the COVID-19 pandemic

Umbilical cord blood (UCB) is an irreplaceable source for hematopoietic stem progenitor cells (HSPCs). However, the effects of SARS-CoV-2 infection and COVID-19 vaccination on UCB phenotype, specifically the HSPCs therein, are currently unknown. We thus evaluated any effects of SARS-CoV-2 infection and/or COVID-19 vaccination from the mother on the fate and functionalities of HSPCs in the UCB. The numbers and frequencies of HSPCs in the UCB decreased significantly in donors with previous SARS-CoV-2 infection and more so with COVID-19 vaccination via the induction of apoptosis, likely mediated by IFN-γ-dependent pathways. Two independent hematopoiesis assays, a colony forming unit assay and a mouse humanization assay, revealed skewed hematopoiesis of HSPCs obtained from donors delivered from mothers with SARS-CoV-2 infection history. These results indicate that SARS-CoV-2 infection and COVID-19 vaccination impair the functionalities and survivability of HSPCs in the UCB, which would make unprecedented concerns on the future of HSPC-based therapies.

Intervention effects of traditional Chinese medicine on stem cell therapy of myocardial infarction

Cardiovascular diseases are the leading cause of global mortality, in which myocardial infarction accounts for 46% of total deaths. Although good progress has been achieved in medication and interventional techniques, a proven method to repair the damaged myocardium has not yet been determined. Stem cell therapy for damaged myocardial repair has evolved into a promising treatment for ischemic heart disease. However, low retention and poor survival of the injected stem cells are the major obstacles to achieving the intended therapeutic effects. Chinese botanical and other natural drug substances are a rich source of effective treatment for various diseases. As such, numerous studies have revealed the role of Chinese medicine in stem cell therapy for myocardial infarction treatment, including promoting proliferation, survival, migration, angiogenesis, and differentiation of stem cells. Here, we discuss the potential and limitations of stem cell therapy, as well as the regulatory mechanism of Chinese medicines underlying stem cell therapy. We focus on the evidence from pre-clinical trials and clinical practices, and based on traditional Chinese medicine theories, we further summarize the mechanisms of Chinese medicine treatment in stem cell therapy by the commonly used prescriptions. Despite the pre-clinical evidence showing that traditional Chinese medicine is helpful in stem cell therapy, there are still some limitations of traditional Chinese medicine therapy. We also systematically assess the detailed experimental design and reliability of included pharmacological research in our review. Strictly controlled animal models with multi-perspective pharmacokinetic profiles and high-grade clinical evidence with multi-disciplinary efforts are highly demanded in the future.

Stem cell membrane-coated abiotic nanomaterials for biomedical applications

Nanoscale materials have been extensively employed for diagnostic and therapeutic purposes. However, the developed nanosystems still suffer from some limitations, namely the rapid elimination by the immune system, lack of targeting to specific cells, and insufficient biocompatibility. Therefore, novel strategies based upon a biomimetic approach have received attention to improving the pharmacokinetics and safety profile of nanosystems. One promising strategy is the application of a biomimetic coating consisting of cell membranes derived from different cell types onto nanoparticle cores. Stem cells have been investigated to develop targeted nanodevices owing to their excellent intrinsic tissue-specific homing features, protecting them from the immune system to reach the sites of inflammation. This targeting ability is conferred by a surface repertoire of stem cell-associated biomolecules. Such nanoscopical materials offer sustained circulation and boosted drug accumulation at target sites, augmenting therapeutic efficacy and safety. Additionally, the coating of nanoparticles with cell membranes acts as a camouflage mechanism to increase their circulation time. The current review explores the particular features of stem cell membrane coating as multifunctional biomimetic surface functionalization agents to camouflage nanoparticle cores. Biomedical applications of engineered stem cell membrane-coated nanoparticles, challenges in clinical translation, and their future prospects are addressed.

Non-neutral clonal selection and its potential role in mammalian germline stem cell dysfunction with advancing age

The concept of natural selection, or "survival of the fittest", refers to an evolutionary process in nature whereby traits emerge in individuals of a population through random gene alterations that enable those individuals to better adapt to changing environmental conditions. This genetic variance allows certain members of the population to gain an advantage over others in the same population to survive and reproduce in greater numbers under new environmental pressures, with the perpetuation of those advantageous traits in future progeny. Here we present that the behavior of adult stem cells in a tissue over time can, in many respects, be viewed in the same manner as evolution, with each stem cell clone being representative of an individual within a population. As stem cells divide or are subjected to cumulative oxidative damage over the lifespan of the organism, random genetic alterations are introduced into each clone that create variance in the population. These changes may occur in parallel to, or in response to, aging-associated changes in microenvironmental cues perceived by the stem cell population. While many of these alterations will be neutral or silent in terms of affecting cell function, a small fraction of these changes will enable certain clones to respond differently to shifts in microenvironmental conditions that arise with advancing age. In some cases, the same advantageous genetic changes that support survival and expansion of certain clones over others in the population (viz. non-neutral competition) could be detrimental to the downstream function of the differentiated stem cell descendants. In the context of the germline, such a situation would be devastating to successful propagation of the species across generations. However, even within a single generation, the “evolution” of stem cell lineages in the body over time can manifest into aging-related organ dysfunction and failure, as well as lead to chronic inflammation, hyperplasia, and cancer. Increased research efforts to evaluate stem cells within a population as individual entities will improve our understanding of how organisms age and how certain diseases develop, which in turn may open new opportunities for clinical detection and management of diverse pathologies.

Dental Pulp-Derived Stem Cells Reduce Inflammation, Accelerate Wound Healing and Mediate M2 Polarization of Myeloid Cells

This work aimed to validate the potential use of dental pulp-derived stem cells (DPSCs) for the treatment of inflammation by defining their mechanisms of action. We planned to investigate whether priming of DPSC with proinflammatory molecules had any impact on their behavior and function. In the first step of our validation in vitro, we showed that priming of DPSCs with the bioactive agents LPS, TNF-α, or IFN-γ altered DPSCs’ immunologic properties by increasing their expression levels of IL-10, HGF, IDO, and IL-4 and by decreasing their mitochondrial functions. Moreover, DPSCs induced accelerated wound healing irrespective of priming, as determined by using a gut epithelial cell line in a scratch wound assay. Wound healing of gut epithelial cells was mediated by regulating the expressions of AKT, NF-κB, and ERK1/2 proteins compared to the control epithelial cells. In addition, primed DPSCs altered monocyte polarization toward an immuno-suppressive phenotype (M2), where monocytes expressed higher levels of IL-4R, IL-6, Arg1, and YM-1 compared to monocytes cultured with control DPSCs. In silico analysis revealed that this was accomplished in part by the interaction between kynurenine and PPARγ, which regulated the expression of M2 differentiation-related genes. Collectively, these data provided evidence that the DPSCs reduced inflammation, induced M2 polarization of myeloid cells, and healed damaged gut epithelial cells through inactivation of inflammation and modulating constitutively active signaling pathways.

Stem cells and common biomaterials in dentistry: a review study

Stem cells exist as normal cells in embryonic and adult tissues. In recent years, scientists have spared efforts to determine the role of stem cells in treating many diseases. Stem cells can self-regenerate and transform into some somatic cells. They would also have a special position in the future in various clinical fields, drug discovery, and other scientific research. Accordingly, the detection of safe and low-cost methods to obtain such cells is one of the main objectives of research. Jaw, face, and mouth tissues are the rich sources of stem cells, which more accessible than other stem cells, so stem cell and tissue engineering treatments in dentistry have received much clinical attention in recent years. This review study examines three essential elements of tissue engineering in dentistry and clinical practice, including stem cells derived from the intra- and extra-oral sources, growth factors, and scaffolds.

Cocktail Formula and Application Prospects for Oral and Maxillofacial Organoids

Oral and maxillofacial organoids (OMOs), tiny tissues and organs derived from stem cells cultured through 3-d cell culture models, can fully summarize the cell tissue structure, physiological functions and biological characteristics of the source tissues in the body. OMOs are applied in areas such as disease modelling, developmental and regenerative medicine, drug screening, personalized treatment, etc. Although the construction of organoids in various parts of the oral and maxillofacial (OM) region has achieved considerable success, the existing cocktail formulae (construction strategies) are not widely applicable for tissues of various sources due to factors including the heterogeneity of the source tissues and the dependence on laboratory technology. Most of their formulae are based on growth factor niches containing expensive recombinant proteins with their efficiency remaining to be improved. In view of this, the cocktail formulae of various parts of the OM organs are reviewed with further discussion of the application and prospects for those OMOs to find some affordable cocktail formula with strong operability and high repeatability for various maxillofacial organs. The results may help improve the efficiency of organoid construction in the laboratory and accelerate the pace of the clinical use of organoid technology.

Engineering Islets From Stem Cells: The Optimal Solution for the Treatment of Diabetes?

Diabetes is a metabolic disease characterized by insulin deficiency. Bioengineering of stem cells with the aim to restore insulin production and glucose regulation has the potential to cure diabetic patients. In this review, we focus on the recent developments for bioengineering of induced pluripotent stem cells (iPSCs), mesenchymal stem cells (MSCs), embryonic stem cells (ESCs), and pancreatic progenitor cells in view of generating insulin producing and glucose regulating cells for β-cell replacement therapies. Recent clinical trials using islet cells derived from stem cells have been initiated for the transplantation into diabetic patients, with crucial bottlenecks of tumorigenesis, post-transplant survival, genetic instability, and immunogenicity that should be further optimized. As a new approach given high expectations, bioengineered islets from stem cells occupies considerable potential for the future clinical application and addressing the treatment dilemma of diabetes.

Glycogene Expression Profile of Human Limbal Epithelial Cells with Distinct Clonogenic Potential

Glycans function as valuable markers of stem cells but also regulate the ability of these cells to self-renew and differentiate. Approximately 2% of the human genome encodes for proteins that are involved in the biosynthesis and recognition of glycans. In the present study, we evaluated the expression of a small subset of glycogenes in human limbal epithelial cells with distinct clonogenic potential. Individual clones were classified as abortive or clonogenic, based on the fraction of the terminal colonies produced; clones leading exclusively to terminal colonies were referred to as abortive while those with half or fewer terminal colonies were referred to as clonogenic. An analysis of glycogene expression in clonogenic cultures revealed a high content of transcripts regulating the galactose and mannose metabolic pathways. Abortive clones were characterized by increased levels of GCNT4 and FUCA2, genes that are responsible for the branching of mucin-type O-glycans and the hydrolysis of fucose residues on N-glycans, respectively. The expansion of primary cultures of human limbal epithelial cells for 10 days resulted in stratification and a concomitant increase in MUC16, GCNT4 and FUCA2 expression. These data indicate that the clonogenic potential of human limbal epithelial cells is associated with specific glycosylation pathways. Mucin-type O-glycan branching and increased fucose metabolism are linked to limbal epithelial cell differentiation.

Mesenchymal Stem Cell-Derived Extracellular Vesicles in the Management of COVID19-Associated Lung Injury: A Review on Publications, Clinical Trials and Patent Landscape

The unprecedented COVID-19 pandemic situation forced the scientific community to explore all the possibilities from various fields, and so far we have seen a lot of surprises, eureka moments and disappointments. One of the approaches from the cellular therapists was exploiting the immunomodulatory and regenerative potential of mesenchymal stromal cells (MSCs), more so of MSC-derived extracellular vesicles (EVs)—particularly exosomes, in order to alleviate the cytokine storm and regenerate the damaged lung tissues. Unlike MSCs, the EVs are easier to store, deliver, and are previously shown to be as effective as MSCs, yet less immunogenic. These features attracted the attention of many and thus led to a tremendous increase in publications, clinical trials and patent applications. This review presents the current landscape of the field and highlights some interesting findings on MSC-derived EVs in the context of COVID-19, including in silico, in vitro, in vivo and case reports. The data strongly suggests the potential of MSC-derived EVs as a therapeutic regime for the management of acute lung injury and associated complications in COVID-19 and beyond.

N6-Methyladenosine RNA Modification: A Potential Regulator of Stem Cell Proliferation and Differentiation

Stem cell transplantation (SCT) holds great promise for overcoming diseases by regenerating damaged cells, tissues and organs. The potential for self-renewal and differentiation is the key to SCT. RNA methylation, a dynamic and reversible epigenetic modification, is able to regulate the ability of stem cells to differentiate and regenerate. N⁶-methyladenosine (m⁶A) is the richest form of RNA methylation in eukaryotes and is regulated by three classes of proteins: methyltransferase complexes, demethylase complexes and m⁶A binding proteins. Through the coordination of these proteins, RNA methylation precisely modulates the expression of important target genes by affecting mRNA stability, translation, selective splicing, processing and microRNA maturation. In this review, we summarize the most recent findings on the regulation of m⁶A modification in embryonic stem cells, induced pluripotent stem cells and adult stem cells, hoping to provide new insights into improving SCT technology.

Senescence-Associated Cell Transition and Interaction (SACTAI): A Proposed Mechanism for Tissue Aging, Repair, and Degeneration

Aging is a broad process that occurs as a time-dependent functional decline and tissue degeneration in living organisms. On a smaller scale, aging also exists within organs, tissues, and cells. As the smallest functional unit in living organisms, cells “age” by reaching senescence where proliferation stops. Such cellular senescence is achieved through replicative stress, telomere erosion and stem cell exhaustion. It has been shown that cellular senescence is key to tissue degradation and cell death in aging-related diseases (ARD). However, senescent cells constitute only a small percentage of total cells in the body, and they are resistant to death during aging. This suggests that ARD may involve interaction of senescent cells with non-senescent cells, resulting in senescence-triggered death of non-senescent somatic cells and tissue degeneration in aging organs. Here, based on recent research evidence from our laboratory and others, we propose a mechanism—Senescence-Associated Cell Transition and Interaction (SACTAI)—to explain how cell heterogeneity arises during aging and how the interaction between somatic cells and senescent cells, some of which are derived from aging somatic cells, results in cell death and tissue degeneration.

[Cell therapy for destructive pancreatitis]

OBJECTIVE

To evaluate therapeutic efficacy of mesenchymal stem cells in patients with severe acute pancreatitis.

MATERIAL AND METHODS

There were 60 patients with severe acute pancreatitis randomized into 2 groups: the first group (n=30) - endoscopic surgical treatment, mean age 44.7±2.93 years (18 (60.0%) males and 12 (40.0%) females); the second group (n=30) - complex therapy (standard treatment + cell therapy), mean age 50.8±3.8 years (16 (53.3%) men and 14 (46.7%) women). Taxation of endogenous intoxication, immunity state and regional microcirculation were assessed. Genetic analysis of eNOS (C774T) gene polymorphism was also carried out.

RESULTS

Early period of acute severe pancreatitis is accompanied by significant disorders of homeostasis (endogenous intoxication, immune imbalance, severe disorders of regional microcirculation). Genetic analysis showed that polymorphic genotype (T774T) of the endothelial NO synthase gene in a larger percentage (66.7-71.6%, p=0.001) occur in patients with severe acute pancreatitis and more severe homeostatic disorders (p<0.05). Inclusion of mesenchymal stem cells into standard therapy in early phase of acute severe pancreatitis makes it possible to purposefully and relatively quickly exert its effect on abnormal processes of homeostasis, inhibiting toxemic phenomenon, restoring immune response, and improving microcirculation. A particularly positive therapeutic effect of the drug is observed in patients with the eNOS gene mutation (T774T).

CONCLUSION

Mesenchymal stem cell drugs are advisable in early period of acute pancreatitis, mainly in patients with severe forms of disease.

Investigating Adult Stem Cells Through Lineage analyses

A simple, universal and fundamental definition of adult stem cell communities is proposed. Key principles of cell lineage methods for defining adult stem cell numbers, locations and behaviors are critically evaluated, emphasizing the imperatives of capturing the full spectrum of individual stem cell behaviors, examining a variety of experimental time periods and avoiding unwarranted assumptions. The focus is first on defining fundamentals and then addresses stem cell heterogeneity, potential hierarchies and how individual cells serve the function of a stem cell community.

Targeting Programmed Cell Death to Improve Stem Cell Therapy: Implications for Treating Diabetes and Diabetes-Related Diseases

Stem cell therapies have shown promising therapeutic effects in restoring damaged tissue and promoting functional repair in a wide range of human diseases. Generations of insulin-producing cells and pancreatic progenitors from stem cells are potential therapeutic methods for treating diabetes and diabetes-related diseases. However, accumulated evidence has demonstrated that multiple types of programmed cell death (PCD) existed in stem cells post-transplantation and compromise their therapeutic efficiency, including apoptosis, autophagy, necroptosis, pyroptosis, and ferroptosis. Understanding the molecular mechanisms in PCD during stem cell transplantation and targeting cell death signaling pathways are vital to successful stem cell therapies. In this review, we highlight the research advances in PCD mechanisms that guide the development of multiple strategies to prevent the loss of stem cells and discuss promising implications for improving stem cell therapy in diabetes and diabetes-related diseases.

Cell Therapy: Types, Regulation, and Clinical Benefits

Cell therapy practices date back to the 19th century and continue to expand on investigational and investment grounds. Cell therapy includes stem cell- and non-stem cell-based, unicellular and multicellular therapies, with different immunophenotypic profiles, isolation techniques, mechanisms of action, and regulatory levels. Following the steps of their predecessor cell therapies that have become established or commercialized, investigational and premarket approval-exempt cell therapies continue to provide patients with promising therapeutic benefits in different disease areas. In this review article, we delineate the vast types of cell therapy, including stem cell-based and non-stem cell-based cell therapies, and create the first-in-literature compilation of the different "multicellular" therapies used in clinical settings. Besides providing the nuts and bolts of FDA policies regulating their use, we discuss the benefits of cell therapies reported in 3 therapeutic areas-regenerative medicine, immune diseases, and cancer. Finally, we contemplate the recent attention shift toward combined therapy approaches, highlighting the factors that render multicellular therapies a more attractive option than their unicellular counterparts.

Identification and characterization of murine adipose tissue-derived somatic stem cells of Shenque (CV8) acupoint

Background:

Shenque (CV8) acupoint is located on the navel and has been therapeutically used for more than 2000 years in Traditional Chinese Medicine (TCM). However, clinical research on the underlying therapeutic molecular mechanisms of the CV8 acupoint lags far behind. This study aimed to study the mechanisms of umbilical acupoint therapy by using stem cells.

Methods:

The morphological characteristics of CV8 acupoint were detected under a stereomicroscope using hematoxylin and eosin (H&E) staining. Oil Red, Masson, and immunohistochemical staining on multi-layered slices were used to identify the type of cells at the CV8 acupoint. Cell proliferation was measured by a cell counting kit-8 (CCK-8) method. Flow cytometry and immunohistochemistry were used for cell identification. Induced differentiation was used to compare the differentiation of cells derived from CV8 acupoint and non-acupoint somatic stem cells into other cell types, such as osteogenic, adipogenic, and neural stem cell-like cells.

Results:

Morphological observations showed that adipose tissues at the linea alba of the CV8 acupoint in mice had a mass-like distribution. Immunohistochemical staining confirmed the distribution of stem cell antigen-1 (Sca-1) positive cells in the multi-layered slices of CV8 acupoint tissues. Cells isolated from adipose tissues at the CV8 acupoint exhibited high expression of Sca-1 and CD44 and low expression of CD31 and CD34, and these cells possessed osteogenic, adipogenic, and neurogenic stem cell-like cell differentiation ability. The cell proliferation (day 4: 0.5138 ± 0.0111 vs. 0.4107 ± 0.0180, t = 8.447, P = 0.0011; day 5: 0.6890 ± 0.0070 vs. 0.5520 ± 0.0118, t = 17.310, P < 0.0001; day 6: 0.7320 ± 0.0090 vs. 0.6157 ± 0.0123, t = 13.190, P = 0.0002; and day 7: 0.7550 ± 0.0050 vs. 0.6313 ± 0.0051, t = 42.560, P < 0.0001), adipogenic ([9.224 ± 0.345]% vs. [3.933 ± 1.800]%, t = 5.000, P = 0.0075), and neurogenic stem cell-like cell differentiation (diameter < 50 μm: 7.2000 ± 1.3040 vs. 2.6000 ± 0.5477, t = 7.273, P < 0.0001; diameter 50–100 μm: 2.6000 ± 0.5477 vs. 1.0000 ± 0.7071, t = 4.000, P = 0.0039; and diameter >100 μm: 2.6000 ± 0.5477 vs. 0.8000 ± 0.8367, t = 4.025, P = 0.0038) were significantly enhanced in somatic stem cells derived from the CV8 acupoint compared to somatic stem cells from the groin non-acupoint. However, cells possessed significantly weaker osteogenicity ([2.697 ± 0.627]% vs. [7.254 ± 0.958]%, t = 6.893, P = 0.0023) in the CV8 acupoint group.

Conclusions:

Our study showed that CV8 acupoint was rich with adipose tissues that contained abundant somatic stem cells. The biological examination of somatic stem cells derived from the CV8 acupoint provided novel insights for future research on the mechanisms of umbilical therapy.

Understanding Drivers of Ocular Fibrosis: Current and Future Therapeutic Perspectives

Ocular fibrosis leads to severe visual impairment and blindness worldwide, being a major area of unmet need in ophthalmology and medicine. To date, the only available treatments are antimetabolite drugs that have significant potentially blinding side effects, such as tissue damage and infection. There is thus an urgent need to identify novel targets to prevent/treat scarring and postsurgical fibrosis in the eye. In this review, the latest progress in biological mechanisms underlying ocular fibrosis are discussed. We also summarize the current knowledge on preclinical studies based on viral and non-viral gene therapy, as well as chemical inhibitors, for targeting TGFβ or downstream effectors in fibrotic disorders of the eye. Moreover, the role of angiogenetic and biomechanical factors in ocular fibrosis is discussed, focusing on related preclinical treatment approaches. Moreover, we describe available evidence on clinical studies investigating the use of therapies targeting TGFβ-dependent pathways, angiogenetic factors, and biomechanical factors, alone or in combination with other strategies, in ocular tissue fibrosis. Finally, the recent progress in cell-based therapies for treating fibrotic eye disorders is discussed. The increasing knowledge of these disorders in the eye and the promising results from testing of novel targeted therapies could offer viable perspectives for translation into clinical use.

An Integrated View of Virus-Triggered Cellular Plasticity Using Boolean Networks

Virus-related mortality and morbidity are due to cell/tissue damage caused by replicative pressure and resource exhaustion, e.g., HBV or HIV; exaggerated immune responses, e.g., SARS-CoV-2; and cancer, e.g., EBV or HPV. In this context, oncogenic and other types of viruses drive genetic and epigenetic changes that expand the tumorigenic program, including modifications to the ability of cancer cells to migrate. The best-characterized group of changes is collectively known as the epithelial–mesenchymal transition, or EMT. This is a complex phenomenon classically described using biochemistry, cell biology and genetics. However, these methods require enormous, often slow, efforts to identify and validate novel therapeutic targets. Systems biology can complement and accelerate discoveries in this field. One example of such an approach is Boolean networks, which make complex biological problems tractable by modeling data (“nodes”) connected by logical operators. Here, we focus on virus-induced cellular plasticity and cell reprogramming in mammals, and how Boolean networks could provide novel insights into the ability of some viruses to trigger uncontrolled cell proliferation and EMT, two key hallmarks of cancer.

Engrafted stem cell therapy for Alzheimer's disease: A promising treatment strategy with clinical outcome

To date, although the microscopic alterations present in Alzheimer's disease (AD) have been well known for over a century only a handful of symptomatic treatments have been developed which are a far cry from a full cure providing volatile benefits. In this context, the intervention of stem cell therapy (SCT) has been proposed as an auxiliary treatment for AD as suggested by the rising number of pre-clinical studies that stem cell engraftment could provide an exciting future treatment regimen against neurodegeneration. Although, most of the primary enthusiasm about this approach was based on replacing deteriorating neurons, the latest studies have implied that the positive modulations fostered by stem cells are fuelled by bystander effects. Present review provides a detailed update on stem cell therapy for AD along with meticulous discussion regarding challenges in developing different stem cells from an aspect of experiment to clinical research and their potential in the milieu of AD hallmarks. Specifically, we focus and provide in depth view on recent advancements in the discipline of SCT aiming to repopulate or regenerate the degenerating neuronal circuitry in AD using stem-cell-on-a-chip and 3D bioprinting techniques. The focus is specifically on the successful restoration of cognitive functions upon engraftment of stem cells on in vivo models for the benefit of the current researchers and their understanding about the status of SCT in AD and finally summarizing on what future holds for SCT in the treatment of AD.

Combination of Stem Cells and Rehabilitation Therapies for Ischemic Stroke

Stem cell transplantation with rehabilitation therapy presents an effective stroke treatment. Here, we discuss current breakthroughs in stem cell research along with rehabilitation strategies that may have a synergistic outcome when combined together after stroke. Indeed, stem cell transplantation offers a promising new approach and may add to current rehabilitation therapies. By reviewing the pathophysiology of stroke and the mechanisms by which stem cells and rehabilitation attenuate this inflammatory process, we hypothesize that a combined therapy will provide better functional outcomes for patients. Using current preclinical data, we explore the prominent types of stem cells, the existing theories for stem cell repair, rehabilitation treatments inside the brain, rehabilitation modalities outside the brain, and evidence pertaining to the benefits of combined therapy. In this review article, we assess the advantages and disadvantages of using stem cell transplantation with rehabilitation to mitigate the devastating effects of stroke.

Age-related alteration in characteristics, function, and transcription features of ADSCs

BACKGROUND AND OBJECTIVES

Adipose tissue-derived stem cells (ADSCs) autologous transplantation has been a promising strategy for aging-related disorders. However, the relationship between ADSCs senescence and organismal aging has not been clearly established. Therefore, we aimed at evaluating senescence properties of ADSCs from different age donors and to verify the influence of organismal aging on the proliferation and function of ADSCs in vitro, providing the theoretical basis for the clinical application of autologous ADSCs transplantation.

METHODS AND RESULTS

The ADSCs were obtained from 1-month-old and 20-month-old mice. The cells characteristics, functions, gene expression levels, apoptosis proportion, cell cycle, SA-β-gal staining, and transcription features were evaluated. Compared to ADSCs from 1-month-old mice, ADSCs from 20-month-old mice exhibited some senescence-associated changes, including inhibited abilities to proliferate. Moreover, differentiation abilities, cell surface markers, and cytokines secreting differed between 1M and 20M ADSCs. SA-β-Gal staining did not reveal differences between the two donor groups, while cells exhibited more remarkable age-related changes through continuous passages. Based on transcriptome analysis and further detection, the CCL7-CCL2-CCR2 axis is the most probable mechanism for the differences.

CONCLUSIONS

ADSCs from old donors have some age-related alterations. The CCL7-CCL2-CCR2 axis is a potential target for gene therapy to reduce the harmful effects of ADSCs from old donors. To improve on autologous transplantation, we would recommend that ADSCs should be cryopreserved in youth with a minimum number of passages or block CCL7-CCL2-CCR2 to abolish the effects of age-related alterations in ADSCs through the Chemokine signaling pathway.

Estrogen- and Progesterone (P4)-Mediated Epigenetic Modifications of Endometrial Stromal Cells (EnSCs) and/or Mesenchymal Stem/Stromal Cells (MSCs) in the Etiopathogenesis of Endometriosis

Endometriosis is a common chronic inflammatory condition in which endometrial tissue appears outside the uterine cavity. Because ectopic endometriosis cells express both estrogen and progesterone (P4) receptors, they grow and undergo cyclic proliferation and breakdown similar to the endometrium. This debilitating gynecological disease affects up to 15% of reproductive aged women. Despite many years of research, the etiopathogenesis of endometrial lesions remains unclear. Retrograde transport of the viable menstrual endometrial cells with retained ability for attachment within the pelvic cavity, proliferation, differentiation and subsequent invasion into the surrounding tissue constitutes the rationale for widely accepted implantation theory. Accordingly, the most abundant cells in the endometrium are endometrial stromal cells (EnSCs). These cells constitute a particular population with clonogenic activity that resembles properties of mesenchymal stem/stromal cells (MSCs). Thus, a significant role of stem cell-based dysfunction in formation of the initial endometrial lesions is suspected. There is increasing evidence that the role of epigenetic mechanisms and processes in endometriosis have been underestimated. The importance of excess estrogen exposure and P4 resistance in epigenetic homeostasis failure in the endometrial/endometriotic tissue are crucial. Epigenetic alterations regarding transcription factors of estrogen and P4 signaling pathways in MSCs are robust in endometriotic tissue. Thus, perspectives for the future may include MSCs and EnSCs as the targets of epigenetic therapies in the prevention and treatment of endometriosis. Here, we reviewed the current known changes in the epigenetic background of EnSCs and MSCs due to estrogen/P4 imbalances in the context of etiopathogenesis of endometriosis. Graphical Abstract.

The Outcome of Stem Cell-Based Therapies on the Immune Responses in Rheumatoid Arthritis

Rheumatoid arthritis as a common autoimmune inflammatory disorder with unknown etiology can affect 0.5-1% of adults in developed countries. It involves more than just the patient's joints and can be accompanied by several comorbidities and affect cardiovascular, pulmonary, and some other systems of the human body. Although cytokine-mediated pathways are mentioned to have a central role in RA pathogenesis, adaptive and innate immune systems and intracellular signaling pathways all have important roles in this process. Non-steroidal anti-inflammatory drugs, glucocorticoids, conventional disease-modifying anti-rheumatic drugs, and biological agents are some mentioned medications used for RA. They are accompanied by some adverse effects and treatment failures which elucidates the needing for novel and more powerful therapeutic approaches. Stem cell-based therapies and their beneficial effects on therapeutic processes of different diseases have been founded so far. They can be an alternative and promising therapeutic approach for RA, too; due to their effects on immune responses of the disease. This review, besides some explanations about RA characteristics, addresses the outcome of the stem cell-based therapies including mesenchymal stem cell transplantation and hematopoietic stem cell transplantation for RA and explains their effects on the disease improvement.

The Use of Stem Cell-Derived Organoids in Disease Modeling: An Update

Organoids represent one of the most important advancements in the field of stem cells during the past decade. They are three-dimensional in vitro culturing models that originate from self-organizing stem cells and can mimic the in vivo structural and functional specificities of body organs. Organoids have been established from multiple adult tissues as well as pluripotent stem cells and have recently become a powerful tool for studying development and diseases in vitro, drug screening, and host-microbe interaction. The use of stem cells-that have self-renewal capacity to proliferate and differentiate into specialized cell types-for organoids culturing represents a major advancement in biomedical research. Indeed, this new technology has a great potential to be used in a multitude of fields, including cancer research, hereditary and infectious diseases. Nevertheless, organoid culturing is still rife with many challenges, not limited to being costly and time consuming, having variable rates of efficiency in generation and maintenance, genetic stability, and clinical applications. In this review, we aim to provide a synopsis of pluripotent stem cell-derived organoids and their use for disease modeling and other clinical applications.

Novel Clinical Therapies and Technologies in Dialysis Vascular Access

The hemodialysis population continues to grow. Although procedures for dialysis have existed for >60 years, significant challenges with vascular access to support hemodialysis persist. Failure of arteriovenous fistulas (AVFs) to mature, loss of AVF and graft patency, thrombosis, and infection hinder long-term access, and add extra health care costs and patient morbidity. There have been numerous innovations over the last decade aimed at addressing the issues. In this study, we review the literature and summarize the recent evolution of drug delivery, graft development, minimally invasive AVF creation, and stem-cell therapy for hemodialysis access.

Programmed cell death in stem cell-based therapy: Mechanisms and clinical applications

Stem cell-based therapy raises hopes for a better approach to promoting tissue repair and functional recovery. However, transplanted stem cells show a high death percentage, creating challenges to successful transplantation and prognosis. Thus, it is necessary to investigate the mechanisms underlying stem cell death, such as apoptotic cascade activation, excessive autophagy, inflammatory response, reactive oxygen species, excitotoxicity, and ischemia/hypoxia. Targeting the molecular pathways involved may be an efficient strategy to enhance stem cell viability and maximize transplantation success. Notably, a more complex network of cell death receives more attention than one crucial pathway in determining stem cell fate, highlighting the challenges in exploring mechanisms and therapeutic targets. In this review, we focus on programmed cell death in transplanted stem cells. We also discuss some promising strategies and challenges in promoting survival for further study.

Stem cell therapy in ocular pathologies in the past 20 years

Stem cell therapies are successfully used in various fields of medicine. This new approach of research is also expanding in ophthalmology. Huge investments, resources and important clinical trials have been performed in stem cell research and in potential therapies. In recent years, great strides have been made in genetic research, which permitted and enhanced the differentiation of stem cells. Moreover, the possibility of exploiting stem cells from other districts (such as adipose, dental pulp, bone marrow stem cells, etc.) for the treatment of ophthalmic diseases, renders this topic fascinating. Furthermore, great strides have been made in biomedical engineering, which have proposed new materials and three-dimensional structures useful for cell therapy of the eye. The encouraging results obtained on clinical trials conducted on animals have given a significant boost in the creation of study protocols also in humans. Results are limited to date, but clinical trials continue to evolve. Our attention is centered on the literature reported over the past 20 years, considering animal (the most represented in literature) and human clinical trials, which are limiting. The aim of our review is to present a brief overview of the main types of treatments based on stem cells in the field of ophthalmic pathologies.

Two Faces of Autophagy in the Struggle against Cancer

Autophagy can play a double role in cancerogenesis: it can either inhibit further development of the disease or protect cells, causing stimulation of tumour growth. This phenomenon is called "autophagy paradox", and is characterised by the features that the autophagy process provides the necessary substrates for biosynthesis to meet the cell's energy needs, and that the over-programmed activity of this process can lead to cell death through apoptosis. The fight against cancer is a difficult process due to high levels of resistance to chemotherapy and radiotherapy. More and more research is indicating that autophagy may play a very important role in the development of resistance by protecting cancer cells, which is why autophagy in cancer therapy can act as a "double-edged sword". This paper attempts to analyse the influence of autophagy and cancer stem cells on tumour development, and to compare new therapeutic strategies based on the modulation of these processes.

Stem Cells and the Endometrium: From the Discovery of Adult Stem Cells to Pre-Clinical Models

Adult stem cells (ASCs) were long suspected to exist in the endometrium. Indeed, several types of endometrial ASCs were identified in rodents and humans through diverse isolation and characterization techniques. Putative stromal and epithelial stem cell niches were identified in murine models using label-retention techniques. In humans, functional methods (clonogenicity, long-term culture, and multi-lineage differentiation assays) and stem cell markers (CD146, SUSD2/W5C5, LGR5, NTPDase2, SSEA-1, or N-cadherin) facilitated the identification of three main types of endogenous endometrial ASCs: stromal, epithelial progenitor, and endothelial stem cells. Further, exogenous populations of stem cells derived from bone marrow may act as key effectors of the endometrial ASC niche. These findings are promoting the development of stem cell therapies for endometrial pathologies, with an evolution towards paracrine approaches. At the same time, promising therapeutic alternatives based on bioengineering have been proposed.

Fighting the War Against COVID-19 via Cell-Based Regenerative Medicine: Lessons Learned from 1918 Spanish Flu and Other Previous Pandemics

The human population is in the midst of battling a rapidly-spreading virus- Severe Acute Respiratory Syndrome Coronavirus 2, responsible for Coronavirus disease 2019 or COVID-19. Despite the resurgences in positive cases after reopening businesses in May, the country is seeing a shift in mindset surrounding the pandemic as people have been eagerly trickling out from federally-mandated quarantine into restaurants, bars, and gyms across America. History can teach us about the past, and today's pandemic is no exception. Without a vaccine available, three lessons from the 1918 Spanish flu pandemic may arm us in our fight against COVID-19. First, those who survived the first wave developed immunity to the second wave, highlighting the potential of passive immunity-based treatments like convalescent plasma and cell-based therapy. Second, the long-term consequences of COVID-19 are unknown. Slow-progressive cases of the Spanish flu have been linked to bacterial pneumonia and neurological disorders later in life, emphasizing the need to reduce COVID-19 transmission. Third, the Spanish flu killed approximately 17 to 50 million people, and the lack of human response, overcrowding, and poor hygiene were key in promoting the spread and high mortality. Human behavior is the most important strategy for preventing the virus spread and we must adhere to proper precautions. This review will cover our current understanding of the pathology and treatment for COVID-19 and highlight similarities between past pandemics. By revisiting history, we hope to emphasize the importance of human behavior and innovative therapies as we wait for the development of a vaccine. Graphical Abstract.

Safety and efficacy of autologous non-hematopoietic enriched stem cell nebulization in COVID-19 patients: a randomized clinical trial, Abu Dhabi 2020

BACKGROUND

The novel SARS-CoV-2 has caused the coronavirus disease 2019 (COVID-19) pandemic. Currently, with insufficient worldwide vaccination rates, identifying treatment solutions to reduce the impact of the virus is urgently needed.

METHOD

An adaptive, multicentric, open-label, and randomized controlled phase I/II clinical trial entitled the "SENTAD-COVID Study" was conducted by the Abu Dhabi Stem Cells Center under exceptional conditional approval by the Emirates Institutional Review Board (IRB) for COVID-19 Research Committee from April 4th to July 31st, 2020, using an autologous peripheral blood non-hematopoietic enriched stem cell cocktail (PB-NHESC-C) administered by compressor (jet) nebulization as a complement to standard care therapy. The primary endpoints include safety and efficacy assessments, adverse events, the mortality rate within 28 days, and the time to clinical improvement as measured by a 2-point reduction on a seven-category ordinal scale or discharge from the hospital whichever occurred first.

RESULTS

The study included a total of 139 randomized COVID-19 patients, with 69 in the experimental group and 70 in the control group (standard care). Overall survival was 94.20% for the cocktail-treated group vs. 90.27% for the control group. Adverse events were reported in 50 (72.46%) patients receiving PB-NHESC-C and 51 (72.85%) in the control group (p = 0.9590), with signs and symptoms commonly found in COVID-19. After the first 9 days of the intervention, 67.3% of cocktail-treated patients recovered and were released from hospitals compared to 53.1% (RR = 0.84; 95% CI, 0.56-1.28) in the control group. Improvement, i.e., at least a 2-point reduction in the severity scale, was more frequently observed in cocktail-treated patients (42.0%) than in controls (17.0%) (RR = 0.69; 95% CI, 0.56-0.88).

CONCLUSIONS

Cocktail treatment improved clinical outcomes without increasing adverse events. Thus, the nebulization of PB-NHESC-C was safe and effective for treatment in most of these patients.

TRIAL REGISTRATION

ClinicalTrials.gov. NCT04473170. It was retrospectively registered on July 16th, 2020.

Role of Human Mesenchymal Stem Cells in Regenerative Therapy

Mesenchymal stem cells (MSCs) are multipotent cells which can proliferate and replace dead cells in the body. MSCs also secrete immunomodulatory molecules, creating a regenerative microenvironment that has an excellent potential for tissue regeneration. MSCs can be easily isolated and grown in vitro for various applications. For the past two decades, MSCs have been used in research, and many assays and tests have been developed proving that MSCs are an excellent cell source for therapy. This review focusses on quality control parameters required for applications of MSCs including colony formation, surface markers, differentiation potentials, and telomere length. Further, the specific mechanisms of action of MSCs under various conditions such as trans-differentiation, cell fusion, mitochondrial transfer, and secretion of extracellular vesicles are discussed. This review aims to underline the applications and benefits of MSCs in regenerative medicine and tissue engineering.