Current status and future prospects of stem cell therapy in Alzheimer's disease

The Major Hypotheses of Alzheimer's Disease: Related Nanotechnology-Based Approaches for Its Diagnosis and Treatment

Alzheimer's disease (AD) is a well-known chronic neurodegenerative disorder that leads to the progressive death of brain cells, resulting in memory loss and the loss of other critical body functions. In March 2019, one of the major pharmaceutical companies and its partners announced that currently, there is no drug to cure AD, and all clinical trials of the new ones have been cancelled, leaving many people without hope. However, despite the clear message and startling reality, the research continued. Finally, in the last two years, the Food and Drug Administration (FDA) approved the first-ever medications to treat Alzheimer's, aducanumab and lecanemab. Despite researchers' support of this decision, there are serious concerns about their effectiveness and safety. The validation of aducanumab by the Centers for Medicare and Medicaid Services is still pending, and lecanemab was authorized without considering data from the phase III trials. Furthermore, numerous reports suggest that patients have died when undergoing extended treatment. While there is evidence that aducanumab and lecanemab may provide some relief to those suffering from AD, their impact remains a topic of ongoing research and debate within the medical community. The fact is that even though there are considerable efforts regarding pharmacological treatment, no definitive cure for AD has been found yet. Nevertheless, it is strongly believed that modern nanotechnology holds promising solutions and effective clinical strategies for the development of diagnostic tools and treatments for AD. This review summarizes the major hallmarks of AD, its etiological mechanisms, and challenges. It explores existing diagnostic and therapeutic methods and the potential of nanotechnology-based approaches for recognizing and monitoring patients at risk of irreversible neuronal degeneration. Overall, it provides a broad overview for those interested in the evolving areas of clinical neuroscience, AD, and related nanotechnology. With further research and development, nanotechnology-based approaches may offer new solutions and hope for millions of people affected by this devastating disease.

A Multicenter Study to Determine Knowledge and Perceptions on Stem Cell Donation, Transplantation Among Saudi Medical Students

BACKGROUND

Despite significant contributions to stem cell research in Saudi Arabia, knowledge and awareness of stem cell research is the subject of ongoing studies with controversial findings, specifically among medical students. This was a cross-sectional study with 685 medical students aimed to explore their knowledge and attitudes in relation to stem cell research and transplantation.

METHODS

A validated survey exploring knowledge and attitudes in relation to stem cell research and transplantation was administered. The total knowledge, attitude, and age scores were presented through mean and SD RESULTS: The results of the present study showed that university students in the Eastern Province had an average 35.88 knowledge of stem cell research. In contrast, the attitudes were positive among the entire study sample, with a mean of 3.79 out of 5. Both men and women had significant knowledge about the definition of stem cells and adult stem cells, bone marrow, whether stem cells can be used for drug testing, and recommended stem cell treatment if available.

CONCLUSIONS

The medical curriculum needs to be refined and enriched with additional data on organ and stem cell donation. This can be further enriched with experimental evidence through additional training initiatives that will allow those with negative attitudes to re-evaluate their perceptions and provide accurate information to patients as future health care providers.

Application of mesenchymal stem cells (MSCs) in neurodegenerative disorders: History, findings, and prospective challenges

Over the past few decades, the application of mesenchymal stem cells has captured the attention of researchers and practitioners worldwide. These cells can be obtained from practically every tissue in the body and are used to treat a broad variety of conditions, most notably neurological diseases such as Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, and Alzheimer's disease. Studies are still being conducted, and the results of these studies have led to the identification of several different molecular pathways involved in the neuroglial speciation process. These molecular systems are closely regulated and interconnected due to the coordinated efforts of many components that make up the machinery responsible for cell signaling. Within the scope of this study, we compared and contrasted the numerous mesenchymal cell sources and their cellular features. These many sources of mesenchymal cells included adipocyte cells, fetal umbilical cord tissue, and bone marrow. In addition, we investigated whether these cells can potentially treat and modify neurodegenerative illnesses.

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.

Nanomedicine-driven therapeutic interventions of autophagy and stem cells in the management of Alzheimer's disease

Drug-loaded, brain-targeted nanocarriers could be a promising tool in overcoming the challenges associated with Alzheimer's disease therapy. These nanocargoes are enormously flexible to functionalize and facilitate the delivery of drugs to brain cells by bridging the blood-brain barrier and into brain cells. To date, modifications have included nanoparticles (NPs) coating with tunable surfactants/phospholipids, covalently attaching polyethylene glycol chains (PEGylation), and tethering different targeting ligands to cell-penetrating peptides in a manner that facilitates their entry across the BBB and downregulates various pathological hallmarks as well as intra- and extracellular signaling pathways. This review provides a brief update on drug-loaded, multifunctional nanocarriers and the therapeutic intervention of autophagy and stem cells in the management of Alzheimer's disease.

Stem Cell-Based Therapeutic Approaches in Genetic Diseases

Stem cells, which can self-renew and differentiate into different cell types, have become the keystone of regenerative medicine due to these properties. With the achievement of superior clinical results in the therapeutic approaches of different diseases, the applications of these cells in the treatment of genetic diseases have also come to the fore. Foremost, conventional approaches of stem cells to genetic diseases are the first approaches in this manner, and they have brought safety issues due to immune reactions caused by allogeneic transplantation. To eliminate these safety issues and phenotypic abnormalities caused by genetic defects, firstly, basic genetic engineering practices such as vectors or RNA modulators were combined with stem cell-based therapeutic approaches. However, due to challenges such as immune reactions and inability to target cells effectively in these applications, advanced molecular methods have been adopted in ZFN, TALEN, and CRISPR/Cas genome editing nucleases, which allow modular designs in stem cell-based genetic diseases' therapeutic approaches. Current studies in genetic diseases are in the direction of creating permanent treatment regimens by genomic manipulation of stem cells with differentiation potential through genome editing tools. In this chapter, the stem cell-based therapeutic approaches of various vital genetic diseases were addressed wide range from conventional applications to genome editing tools.

Neural Stem Cells in the Treatment of Alzheimer's Disease: Current Status, Challenges, and Future Prospects

Alzheimer's disease (AD), a progressive dementia, is one of the world's most dangerous and debilitating diseases. Clinical trial results of amyloid-β (Aβ) and tau regulators based on the pretext of straightforward amyloid and tau immunotherapy were disappointing. There are currently no effective strategies for slowing the progression of AD. Further understanding of the mechanisms underlying AD and the development of novel therapeutic options are critical. Neurogenesis is impaired in AD, which contributes to memory deficits. Transplanted neural stem cells (NSCs) can regenerate degraded cholinergic neurons, and new neurons derived from NSCs can form synaptic connections with neighboring neurons. In theory, employing NSCs to replace and restore damaged cholinergic neurons and brain connections may offer new treatment options for AD. However there remain barriers to surmount before NSC-based therapy can be used clinically. The objective of this article is to describe recent advances in the treatment of AD models and clinical trials involving NSCs. In addition, we discuss the challenges and prospects associated with cell transplant therapy for AD.

Amyloid β, Lipid Metabolism, Basal Cholinergic System, and Therapeutics in Alzheimer’s Disease

The presence of insoluble aggregates of amyloid β (Aβ) in the form of neuritic plaques (NPs) is one of the main features that define Alzheimer’s disease. Studies have suggested that the accumulation of these peptides in the brain significantly contributes to extensive neuronal loss. Furthermore, the content and distribution of cholesterol in the membrane have been shown to have an important effect on the production and subsequent accumulation of Aβ peptides in the plasma membrane, contributing to dysfunction and neuronal death. The monomeric forms of these membrane-bound peptides undergo several conformational changes, ranging from oligomeric forms to beta-sheet structures, each presenting different levels of toxicity. Aβ peptides can be internalized by particular receptors and trigger changes from Tau phosphorylation to alterations in cognitive function, through dysfunction of the cholinergic system. The goal of this review is to summarize the current knowledge on the role of lipids in Alzheimer’s disease and their relationship with the basal cholinergic system, as well as potential disease-modifying therapies.

Promising Stem Cell therapy in the Management of HIV and AIDS: A Narrative Review

Stem cell therapies are becoming a major topic in biomedical research all over the planet. It may be a viable treatment choice for people suffering from a wide range of illnesses and injuries. It has recently emerged as an extremely intriguing and well-established science and research topic. Expectations have risen due to advancements in therapeutic approaches. Multiple laboratory testing of regulated stem cell culture and derivation is carried out before the formation of stem cells for the use of therapeutic process. Whereas HIV infection is contagious and can last a lifetime. Researchers are still working to develop a comprehensive and effective treatment for HIV and its associated condition, as well as AIDS. HIV propagation is primarily restricted to the immune system, notably T lymphocytes, as well as macrophages. Large numbers of research studies have contributed to a plethora of data about the enigmatic AIDS life cycle. This vast amount of data provides potential targets for AIDS therapies. Currently, stem cell transplantation, along with other procedures, provided novel insights into HIV pathogenesis and offered a glimpse of hope for the development of a viable HIV cure technique. One of its existing focus areas in HIV and AIDS research is to develop a novel therapeutic strategic plan capable of providing life-long complete recovery of HIV and AIDS without regular drug treatment and, inevitably, curative therapy for HIV and AIDS. The current paper tries to address the possibilities for improved stem cell treatments with "bone marrow, Hematopoietic, human umbilical cord mesenchymal, Genetical modifications with CRISPR/Cas9 in combination of stem cells, induced pluripotent stem cells applications" are discussed which are specifically applied in the HIV and AIDS therapeutic management advancement procedures.

The Angelica dahurica: A Review of Traditional Uses, Phytochemistry and Pharmacology

Angelica dahurica (A. dahurica) root is a famous edible medicinal herb that has been used in China for thousands of years. To date, more than 300 chemical constituents have been discovered from A. dahurica. Among these ingredients, coumarins and volatile oils are the major active compounds. Moreover, a few other compounds have also been isolated from the root of A. dahurica, such as alkaloids, phenols, sterols, benzofurans, polyacetylenes and polysaccharides. Modern pharmacological studies demonstrated that the root of A. dahurica and its active components displayed various bioactivities such as anti-inflammation, anti-tumor, anti-oxidation, analgesic activity, antiviral and anti-microbial effects, effects on the cardiovascular system, neuroprotective function, hepatoprotective activity, effects on skin diseases and so on. Based on these studies, this review focused on the research publications of A. dahurica and aimed to summarize the advances in the traditional uses, phytochemistry and pharmacology which will provide reference for the further studies and applications of A. dahurica.

Stem Cell-based Therapeutic and Diagnostic Approaches in Alzheimer's Disease

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative impairment mainly recognized by memory loss and cognitive deficits. However, the current therapies against AD are mostly limited to palliative medications, prompting researchers to investigate more efficient therapeutic approaches for AD, such as stem cell therapy. Recent evidence has proposed that extensive neuronal and synaptic loss and altered adult neurogenesis, which is perceived pivotal in terms of plasticity and network maintenance, occurs early in the course of AD, which exacerbates neuronal vulnerability to AD. Thus, regeneration and replenishing the depleted neuronal networks by strengthening the endogenous repair mechanisms or exogenous stem cells and their cargoes is a rational therapeutic approach. Currently, several stem cell-based therapies as well as stem cell products like exosomes, have shown promising results in the early diagnosis of AD.

OBJECTIVE

This review begins with a comparison between AD and normal aging pathophysiology and a discussion on open questions in the field. Next, summarizing the current stem cell-based therapeutic and diagnostic approaches, we declare the advantages and disadvantages of each method. Also, we comprehensively evaluate the human clinical trials of stem cell therapies for AD.

METHODOLOGY

Peer-reviewed reports were extracted through Embase, PubMed, and Google Scholar until 2021.

RESULTS

With several ongoing clinical trials, stem cells and their derivatives (e.g., exosomes) are an emerging and encouraging field in diagnosing and treating neurodegenerative diseases. Although stem cell therapies have been successful in animal models, numerous clinical trials in AD patients have yielded unpromising results, which we will further discuss.

Exploring the Role of Stem Cell Therapy in Treating Neurodegenerative Diseases: Challenges and Current Perspectives

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Several human neurological disorders, such as Parkinson’s disease, Alzheimer’s disease, amyotrophic lateral sclerosis, Huntington’s disease, spinal cord injury, multiple sclerosis, and brain stroke, are caused by the injury to neurons or glial cells. The recent years have witnessed the successful generation of neurons and glia cells driving efforts to develop stem-cell-based therapies for patients to combat a broad spectrum of human neurological diseases. The inadequacy of suitable cell types for cell replacement therapy in patients suffering from neurological disorders has hampered the development of this promising therapeutic approach. Attempts are thus being made to reconstruct viable neurons and glial cells from different stem cells, such as embryonic stem cells, mesenchymal stem cells, and neural stem cells. Dedicated research to cultivate stem cell-based brain transplantation therapies has been carried out. We aim at compiling the breakthroughs in the field of stem cell-based therapy for the treatment of neurodegenerative maladies, emphasizing the shortcomings faced, victories achieved, and the future prospects of the therapy in clinical settings.

Fe3O4@polydopamine nanoparticle-loaded human umbilical cord mesenchymal stem cells improve the cognitive function in Alzheimer's disease mice by promoting hippocampal neurogenesis

One of the most promising treatments for neurodegenerative diseases is the stem cell therapy; however, there are still some limitations in the treatment of Alzheimer's disease. In this study, superparamagnetic nanoparticles composed of magnetic Fe₃O₄ and polydopamine shells were used to label human umbilical cord mesenchymal stem cells (hUC-MSCs) in order to increase the targeting of hUC-MSCs. Our data suggested that Fe₃O₄@PDA labeling increase the efficiency of hUC-MSCs entering the brain. Moreover, the water maze test showed that compared with hUC-MSCs only, Fe₃O₄@PDA-labeled hUC-MSCs improved the cognitive ability of APP/PS1 transgenic mice more significantly. Other experimental data showed that the expression of essential proteins in the hippocampus, such as Aβ, synaptophysin, brain-derived neurotrophic factor, are affected by Fe₃O₄@PDA coated-hUC-MSCs. The regulation of Fe₃O₄@PDA coated-hUC-MSCs could improve the memory and cognitive ability of AD mice by excessive generation of neuroprotective factors, which might be considered a viable therapy to treat AD.

Extracellular Vesicles Released from Neprilysin Gene-Modified Human Umbilical Cord-Derived Mesenchymal Stem Cell Enhance Therapeutic Effects in an Alzheimer's Disease Animal Model

Alzheimer's disease (AD) animal studies have reported that mesenchymal stem cells (MSCs) have therapeutic effects; however, clinical trial results are controversial. Neprilysin (NEP) is the main cleavage enzyme of β-amyloid (Aβ), which plays a major role in the pathology and etiology of AD. We evaluated whether transplantation of MSCs with NEP gene modification enhances the therapeutic effects in an AD animal model and then investigated these pathomechanisms. We manufactured NEP gene-enhanced human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) and intravenously transplanted them in Aβ_1-42-injected AD animal models. We compared the differences in behavioral tests and immunohistochemical assays between four groups: normal, Aβ_1-42 injection, naïve hUC-MSCs, and NEP-enhanced hUC-MSCs. Both naïve and NEP-enhanced hUC-MSC groups showed significant improvements in memory compared to the Aβ_1-42 injection group. There was no significant difference between naïve and NEP-enhanced hUC-MSC groups. There was a significant decrease in Congo red, BACE-1, GFAP, and Iba-1 and a significant increase in BDNF, NeuN, and NEP in both hUC-MSC groups compared to the Aβ_1-42 injection group. Among them, BDNF, NeuN, GFAP, Iba-1, and NEP showed more significant changes in the NEP-enhanced hUC-MSC group than in the naïve group. After stem cell injection, stem cells were not found. Extracellular vesicles (EVs) were equally observed in the hippocampus in the naïve and NEP-enhanced hUC-MSC groups. However, the EVs of NEP-enhanced hUC-MSCs contained higher amounts of NEP as compared to the EVs of naïve hUC-MSCs. Thus, hUC-MSCs affect AD animal models through stem cell-released EVs. Although there was no significant difference in cognitive function between the hUC-MSC groups, NEP-enhanced hUC-MSCs had superior neurogenesis and anti-inflammation properties compared to naïve hUC-MSCs due to increased NEP in the hippocampus by enriched NEP-possessing EVs. NEP gene-modified MSCs that release an increased amount of NEP within EVs may be a promising therapeutic option in AD treatment.

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.

Intravenous administration of mesenchymal stem cells reduces Tau phosphorylation and inflammation in the 3xTg-AD mouse model of Alzheimer's disease

Mesenchymal stem cell (MSC) administration is a novel and promising therapeutic approach for Alzheimer's disease (AD). Focusing on an intervention easily translatable into clinical practice, we administered allogeneic bone marrow-derived MSCs intravenously in a mouse model of AD (3xTg-AD). We systematically evaluated the effects of a single-dose and multiple-doses of MSCs in young and old mice (5 or 10 months old), comparing the short-term and long-term effects after 1, 2, or 7 months of treatment. A single dose of MSCs in young mice attenuated neuroinflammation 1 and 7 months after injection, whereas multiple-doses did not show any effect. Multiple-doses of MSCs (administered at 5 to 12 mo, or 10 to 12 mo) reduced the β-secretase cleavage of the amyloid precursor protein, although levels of Aβ-42 did not change. Most interestingly, multiple doses of MSCs affected tau hyperphosphorylation. MSCs administered in young mice for 7 months decreased the pathological tau phosphorylation at T205, S214, and T231. MSCs administered in old mice for 2 months decreased tau phosphorylation at S396. Our findings show how different timing and frequency of MSC injections can affect and modulate several aspects of the AD-like neuropathology in the 3xTg-AD mouse model, strengthening the concept of fine-tuning MSC therapy for Alzheimer's disease.

Stem cell therapies and benefaction of somatic cell nuclear transfer cloning in COVID-19 era

BACKGROUND

The global health emergency of COVID-19 has necessitated the development of multiple therapeutic modalities including vaccinations, antivirals, anti-inflammatory, and cytoimmunotherapies, etc. COVID-19 patients suffer from damage to various organs and vascular structures, so they present multiple health crises. Mesenchymal stem cells (MSCs) are of interest to treat acute respiratory distress syndrome (ARDS) caused by SARS-CoV-2 infection.

MAIN BODY

Stem cell-based therapies have been verified for prospective benefits in copious preclinical and clinical studies. MSCs confer potential benefits to develop various cell types and organoids for studying virus-human interaction, drug testing, regenerative medicine, and immunomodulatory effects in COVID-19 patients. Apart from paving the ways to augment stem cell research and therapies, somatic cell nuclear transfer (SCNT) holds unique ability for a wide range of health applications such as patient-specific or isogenic cells for regenerative medicine and breeding transgenic animals for biomedical applications. Being a potent cell genome-reprogramming tool, the SCNT has increased prominence of recombinant therapeutics and cellular medicine in the current era of COVID-19. As SCNT is used to generate patient-specific stem cells, it avoids dependence on embryos to obtain stem cells.

CONCLUSIONS

The nuclear transfer cloning, being an ideal tool to generate cloned embryos, and the embryonic stem cells will boost drug testing and cellular medicine in COVID-19.

Nisin and non-essential amino acids: new perspective in differentiation of neural progenitors from human-induced pluripotent stem cells in vitro

Over the past decades, stem cell therapy has been investigated as a promising approach towards various diseases, including neurodegenerative disorders. Stem cells show the capability to differentiate into neuronal progenitor cells in vitro. In the present study, the differentiation potential of human-induced pluripotent stem cells (hiPSCs) into neural lineages was examined under the efficient induction media containing forskolin and 3-isobutyl-1-methyl-xanthine (IBMX) in the presence of nisin (Ni), non-essential amino acids (NEAA) and combination of those (NEAA-Ni) in vitro. The optimum concentrations of these factors were obtained by MTT assay and acridine orange (AO) staining. The effect of Ni and NEAA on the expression rate of neural-specific markers including NSE, MAP2, and ß-tubulin III was studied via immunocytochemistry (ICC) and real-time RT-PCR analyses. Our results indicated that the induction medium containing Ni or NEAA increased the gene and protein expression of NSE, MAP2, and β-tubulin III on the 14th differentiation day. On the other hand, NEAA-Ni showed a less-differentiated hiPSCs compared to Ni and NEAA alone. In conclusion, the obtained results illustrated that Ni and NEAA could be applied as effective factors for neural differentiation of hiPSCs in the future.

Transplantation of Stem Cells as a Potential Therapeutic Strategy in Neurodegenerative Disorders

Stem cells are considered to have significant capacity to differentiate into various cell types in humans and animals. Unlike specialized cells, these cells can proliferate several times to produce millions of cells. Nowadays, pluripotent stem cells are important candidates to provide a renewable source for the replacement of cells in tissues of interest. The damage to neurons and glial cells in the brain or spinal cord is present in neurological disorders such as Amyotrophic lateral sclerosis, stroke, Parkinson's disease, multiple sclerosis, Alzheimer's disease, Huntington's disease, spinal cord injury, lysosomal storage disorder, epilepsy, and glioblastoma. Therefore, stem cell transplantation can be used as a novel therapeutic approach in cases of brain and spinal cord damage. Recently, researchers have generated neuron-like cells and glial-like cells from embryonic stem cells, mesenchymal stem cells, and neural stem cells. In addition, several experimental studies have been performed for developing stem cell transplantation in brain tissue. Herein, we focus on stem cell therapy to regenerate injured tissue resulting from neurological diseases and then discuss possible differentiation pathways of stem cells to the renewal of neurons.

Chromone-lipoic acid conjugate: Neuroprotective agent having acceptable butyrylcholinesterase inhibition, antioxidant and copper-chelation activities

PURPOSE

Alzheimer's disease (AD) is a multifaceted neurodegenerative disease. To target simultaneously multiple pathological processes involved in AD, natural-origin compounds with unique characteristics are promising scaffolds to develop novel multi-target compounds in the treatment of different neurodegenerative disease, especially AD. In this study, novel chromone-lipoic acid hybrids were prepared to find a new multifunctional lead structure for the treatment of AD.

METHODS

Chromone-lipoic acid hybrids were prepared through click reaction and their neuroprotection and anticholinesterase activity were fully evaluated. The anti-amyloid aggregation, antioxidant and metal-chelation activities of the best compound were also investigated by standard methods to find a new multi-functional agent against AD.

RESULTS

The primary biological screening demonstrated that all compounds had significant neuroprotection activity against H2O2-induced cell damage in PC12 cells. Compound 19 as the most potent butyrylcholinesterase (BuChE) inhibitor (IC50 = 7.55 μM) having significant neuroprotection activity as level as reference drug was selected for further biological evaluations. Docking and kinetic studies revealed non-competitive mixed-type inhibition of BuChE by compound 19. It could significantly reduce formation of the intracellular reactive oxygen species (ROS) and showed excellent reducing power (85.57 mM Fe+2), comparable with quercetin and lipoic acid. It could also moderately inhibit Aβ aggregation and selectively chelate with copper ions in 2:1 M ratio.

CONCLUSION

Compound 19 could be considered as a hopeful multifunctional agent for the further development gainst AD owing to the acceptable neuroprotective and anti-BuChE activity, moderate anti-Aβ aggregation activity, outstanding antioxidant activity as well as selective copper chelation ability. A new chromone-lipoic acid hybrid was synthesized as anti-Alzheimer agent with BuChE inhibitory activity, anti-Aβ aggregation, metal-chelation and antioxidant properties.

Stem Cell-Based Disease Modeling and Cell Therapy

Stem cell science is among the fastest moving fields in biology, with many highly promising directions for translatability. To centralize and contextualize some of the latest developments, this Special Issue presents state-of-the-art research of adult stem cells, induced pluripotent stem cells (iPSCs), and embryonic stem cells as well as cancer stem cells. The studies we include describe efficient differentiation protocols of generation of chondrocytes, adipocytes, and neurons, maturation of iPSC-derived cardiomyocytes and neurons, dynamic characterization of iPSC-derived 3D cerebral organoids, CRISPR/Cas9 genome editing, and non-viral minicircle vector-based gene modification of stem cells. Different applications of stem cells in disease modeling are described as well. This volume also highlights the most recent developments and applications of stem cells in basic science research and disease treatments.

Innovative Therapies and Nanomedicine Applications for the Treatment of Alzheimer's Disease: A State-of-the-Art (2017-2020)

The field of nanomedicine is constantly expanding. Since the first work dated in 1999, almost 28 thousand articles have been published, and more and more are published every year: just think that only in the last five years 20,855 have come out (source PUBMED) including original research and reviews. The goal of this review is to present the current knowledge about nanomedicine in Alzheimer’s disease, a widespread neurodegenerative disorder in the over 60 population that deeply affects memory and cognition. Thus, after a brief introduction on the pathology and on the state-of-the-art research for NPs passing the BBB, special attention is placed to new targets that can enter the interest of nanoparticle designers and to new promising therapies. The authors performed a literature review limited to the last three years (2017–2020) of available studies with the intention to present only novel formulations or approaches where at least in vitro studies have been performed. This choice was made because, while limiting the sector to nanotechnology applied to Alzheimer, an organic census of all the relevant news is difficult to obtain.

Gene Editing and Alzheimer's Disease: Is There Light at the End of the Tunnel?

Alzheimer's disease continues to be a fatal, incurable neurodegenerative disease, despite many years of efforts to find approaches to its treatment. Here we review recent studies on Alzheimer's disease as a target for gene therapy and specifically, gene editing technology. We also review the opportunities and limitations of modern methods of gene therapy based on the CRISPR editing system. The opportunities of using this approach for modeling, including cellular and animal models, studying on pathogenesis and disease correction mechanisms, as well as limitations for its therapeutic use are discussed.

Current state of stem cell-based therapies: an overview

Recent research reporting successful translation of stem cell therapies to patients have enriched the hope that such regenerative strategies may one day become a treatment for a wide range of vexing diseases. In fact, the past few years witnessed, a rather exponential advancement in clinical trials revolving around stem cell-based therapies. Some of these trials resulted in remarkable impact on various diseases. In this review, the advances and challenges for the development of stem-cell-based therapies are described, with focus on the use of stem cells in dentistry in addition to the advances reached in regenerative treatment modalities in several diseases. The limitations of these treatments and ongoing challenges in the field are also discussed while shedding light on the ethical and regulatory challenges in translating autologous stem cell-based interventions, into safe and effective therapies.