Stem Cell Therapy: A Prospective Treatment for Alzheimer's Disease

Stem Cell Therapy and Thiamine Deficiency-Induced Brain Damage

Wernicke's encephalopathy (WE) is a major central nervous system disorder resulting from thiamine deficiency (TD) in which a number of brain regions can develop serious damage including the thalamus and inferior colliculus. Despite decades of research into the pathophysiology of TD and potential therapeutic interventions, little progress has been made regarding effective treatment following the development of brain lesions and its associated cognitive issues. Recent developments in our understanding of stem cells suggest they are capable of repairing damage and improving function in different maladys. This article puts forward the case for the potential use of stem cell treatment as a therapeutic strategy in WE by first examining the effects of TD on brain functional integrity and its consequences. The second half of the paper will address the future benefits of treating TD with these cells by focusing on their nature and their potential to effectively treat neurodegenerative diseases that share some overlapping pathophysiological features with TD. At the same time, some of the obstacles these cells will have to overcome in order to become a viable therapeutic strategy for treating this potentially life-threatening illness in humans will be highlighted.

Dose-dependent neuroprotective effects of adipose-derived mesenchymal stem cells on amyloid β-induced Alzheimer's disease in rats

AIM

Mesenchymal stem cells (MSCs) have emerged as an intriguing candidate in cell therapy for treating neurodegenerative diseases, including Alzheimer's disease (AD). To achieve the maximum efficiency of cell therapy, determining the optimal dose of MSCs is essential. This study was conducted to assess the dose-dependent therapeutic response of MSCs against pathological and behavioral AD-associated alterations.

METHODS

Aβ1-42 was injected intrahippocampally to establish an AD rat model. The MWM test was utilized to evaluate the animal's behavioral functions after receiving low and high doses of MSCs in the hippocampus region. ELISA and RT-qPCR were also employed to assess the concentration of markers related to antioxidant activity and inflammation and the gene expression related to apoptosis in the hippocampus region, respectively.

RESULTS

Low-dose MSC transplantation by increasing the concentrations of the antioxidant GSH, the anti-inflammatory cytokine IL-10, as well as by lowering the concentrations of TNF-α, and the expression levels of apoptotic factors (Bax and caspase 3), exerted a neuroprotective effect in the hippocampus of AD rats and relatively ameliorated spatial learning and memory impairments. However, increasing the dose of MSCs decreased the therapeutic benefits of these cells and had no significant effect on the recovery of behavioral disorders.

CONCLUSION

Our findings reveal the dose-dependent neuroprotective effect of MSCs in AD. The therapeutic response of MSCs to ameliorate the pathological and behavioral alterations associated with AD is attenuated when the dosage of MSCs is increased.

A consolidated review on stem cell therapy for treatment and management of Alzheimer's disease

Alzheimer's disease (AD) is one of the most common forms of dementia and affects around 50 million people around the globe. AD is diagnosed mainly through imaging techniques and to date only five drugs are approved for management of AD but no promising treatment is available for AD. So in this review, we are focusing on stem cell therapy for AD. This review will cover all stem cells like mesenchymal stem cells, embryonic stem cells, induced pluripotent stem cells, and neural stem cells. Clinical trials of AD have also been discussed. Finally, limitations of stem cells are discussed with ongoing clinical trials, and in the future stem cell therapy can be used for treatment of AD.

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.

Metabolic disorder in Alzheimer's disease

Alzheimer's disease (AD), a well known aging-induced neurodegenerative disease is related to amyloid proteinopathy. This proteinopathy occurs due to abnormalities in protein folding, structure and thereby its function in cells. The root cause of such kind of proteinopathy and its related neurodegeneration is a disorder in metabolism, rather metabolomics of the major as well as minor nutrients. Metabolomics is the most relevant "omics" platform that offers a great potential for the diagnosis and prognosis of neurodegenerative diseases as an individual's metabolome. In recent years, the research on such kinds of neurodegenerative diseases, especially aging-related disorders is broadened its scope towards metabolic function. Different neurotransmitter metabolisms are also involved with AD and its associated neurodegeneration. The genetic and epigenetic backgrounds are also noteworthy. In this review, the physiological changes of AD in relation to its corresponding biochemical, genetic and epigenetic involvements including its (AD) therapeutic aspects are discussed.

Alzheimer's disease and its treatment by different approaches: A review

Alzheimer's disease (AD) is a neurodegenerative disorder that impairs mental ability development and interrupts neurocognitive function. This neuropathological condition is depicted by neurodegeneration, neural loss, and development of neurofibrillary tangles and Aβ plaques. There is also a greater risk of developing AD at a later age for people with cardiovascular diseases, hypertension and diabetes. In the biomedical sciences, effective treatment for Alzheimer's disease is a severe obstacle. There is no such treatment to cure Alzheimer's disease. The drug present in the market show only symptomatic relief. The cause of Alzheimer's disease is not fully understood and the blood-brain barrier restricts drug efficacy are two main factors that hamper research. Stem cell-based therapy has been seen as an effective, secure, and creative therapeutic solution to overcoming AD because of AD's multifactorial nature and inadequate care. Current developments in nanotechnology often offer possibilities for the delivery of active drug candidates to address certain limitations. The key nanoformulations being tested against AD include polymeric nanoparticles (NP), inorganic NPs and lipid-based NPs. Nano drug delivery systems are promising vehicles for targeting several therapeutic moieties by easing drug molecules' penetration across the CNS and improving their bioavailability. In this review, we focus on the causes of the AD and their treatment by different approaches.

A quantitative proteomics analysis for small molecule Stemazole's effect on human neural stem cells

BACKGROUND

Stemazole is a novel small molecule that has been suggested to have the ability to protect multiple stem cells. The proliferation-promoting activity and promising neuroprotective effects of stemazole make it a prospective drug for neurodegenerative disease treatment.

METHODS

Since previous studies have shown that it protective effect in extreme conditions, to understand more aspects of stemazole, in this study, a systematic tandem mass tags (TMT)-labelled proteomics approach was used to address the whole proteome expression profile with or without stemazole in normal conditions instead of extreme conditions. Bioinformatics analyses, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment and protein-protein interaction (PPI) network analyses, were employed.

RESULTS

The effect of stemazole on the expression profiles of neural stem cells was obtained. A total of 408 proteins with changes at the abundance level of two groups were identified: 178 proteins increase in abundance and 240 proteins decrease in abundance, respectively. Low abundance of some mitochondrial respiratory chain enzyme, overproduction of reactive oxygen species (ROS) and reduction of mitochondrial membrane potential may indicate stemazole has cytotoxicity.

CONCLUSIONS

It is the first proteomics research about stemazole, and the possible cytotoxicity of stemazole has been reported for the first time. The information about proteins that were affected by stemazole and more characteristics of stemazole will help obtain a complete picture of this small molecule drug. These findings provide a scientific basis for further stemazole treatment research.

Delay of gCJD aggravation in sick TgMHu2ME199K mice by combining NPC transplantation and Nano-PSO administration

gCJD is a fatal late-onset neurodegenerative disease linked to mutations in the PRNP gene. We have previously shown that transplantation of neural precursor cells (NPCs), or administration of a nanoformulation of pomegranate seed oil (Nano-PSO, GranaGard), into newborn asymptomatic TgMHu2ME199K mice modeling for E200K gCJD significantly delayed the advance of clinical disease. In the present study, we tested the individual and combined effects of both treatments in older and sick TgMHu2ME199K mice. We show that while transplantation of NPCs at both initial (140 days) and advance clinical states (230 days) arrested disease progression for about 30 days, after which scores rapidly climbed to those of untreated Tgs, administration of Nano-PSO to transplanted TgMHu2ME199K mice resulted in detention of disease advance for 60-80 days, followed by a slower disease progression thereafter. Pathological examinations demonstrated the combined treatment extended the survival of the transplanted NPCs, and also increased the generation of endogenous stem cells. Our results suggest that administration of Nano-PSO may increase the beneficial effects of NPCs transplantation.

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

Alzheimer's disease is a common progressive neurodegenerative disorder, pathologically characterized by the presence of β-amyloid plaques and neurofibrillary tangles. Current treatment approaches using drugs only alleviate the symptoms without curing the disease, which is a serious issue and influences the quality of life of the patients and their caregivers. In recent years, stem cell technology has provided new insights into the treatment of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Currently, the main sources of stem cells include neural stem cells, embryonic stem cells, mesenchymal stem cells, and induced pluripotent stem cells. In this review, we discuss the pathophysiology and general treatment of Alzheimer's disease, and the current state of stem cell transplantation in the treatment of Alzheimer's disease. We also assess future challenges in the clinical application and drug development of stem cell transplantation as a treatment for Alzheimer's disease.

Pharmacokinetics and absolute oral bioavailability of stemazole by UPLC-MS/MS and its bio-distribution through tritium labeling

The small molecule, stemazole, has significant therapeutic effects on neurodegenerative diseases, such as Alzheimer's disease (AD), due to its neuroprotective effects and remarkable survival-promoting activity in stem cells. However, pharmacokinetic properties of stemazole were unclear. In this study, a rapid and effective ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to detect stemazole. The detector was operated in the positive-ion mode with an electrospray ionization (ESI) interface in multiple reaction monitoring (MRM) mode. Chromatographic separation was performed on an Acquity UPLC^® BEH C₁₈ column with gradient elution. Stemazole was extracted from plasma following a one-step protein precipitation method. The method was fully validated for its selectivity, specificity, and sensitivity. The calibration curve range of 5-1125 ng/mL showed good linearity for stemazole. Intra-day and inter-day precision rates were less than 10%, and accuracy ranged from 95.87% to 105.23%. The pharmacokinetic profiles were illustrated through the newly developed method for the first time. The absolute oral bioavailability of stemazole is 32.10%. Therefore, it is feasible as an oral medication, which greatly facilitates its broad application. The biological distribution of tritium-labeled stemazole in mice was studied, and the results showed that stemazole was absorbed rapidly and distributed widely, mainly in the liver and kidneys. A specific amount was also detected in the brain, which provides a prerequisite for the use of stemazole to treat neurodegenerative diseases. This work represents first description of the pharmacokinetics, bioavailability, and tissue distribution of stemazole and will lay the foundation for further investigation and drug development.

Stem cell therapies for Alzheimer's disease: is it time?

PURPOSE OF REVIEW

Stem cell therapy has the potential to modify the disease of Alzheimer's disease. This article aims to describe the mechanisms of action, preclinical animal studies, human clinical trials, and challenges for the future direction of stem cell therapy for Alzheimer's disease.

RECENT FINDINGS

Stem cells of diverse origins (embryonic, placental or umbilical cord blood, and induced pluripotent stem cells) and cell types (neural and mesenchymal stem cells) are widely studied in both animals and humans.

SUMMARY

In terms of mechanism of actions, recent research focused on the interplay between amyloid-beta Aβ (and tau), neurons, and glia. Stem cells can induce direct regeneration of neurons and synapses. They can also prevent activation of pro-inflammatory microglia, promote activation of anti-inflammatory microglia, inhibit astrogliosis, and promote nonreactive astrocytes. These effects in return may increase amyloid-beta (Aβ) degradation, decrease the risk of the Aβ cascade, repair injured neurons, and enhance synaptogenesis. Two completed and nine ongoing clinical trials using diverse stem cells and administration methods (intravenous, subcutaneous, and intra-cranial) were found for the treatment of Alzheimer's disease. Although stem cell therapy shows great potential to become a prospective treatment for Alzheimer's disease in the future, these studies are still in their early stages and more studies showing safety and efficacy are needed.

Clinical PET Imaging of Microglial Activation: Implications for Microglial Therapeutics in Alzheimer's Disease

In addition to extracellular β-amyloid plaques and intracellular neurofibrillary tangles, neuroinflammation has been identified as a key pathological characteristic of Alzheimer's disease (AD). Once activated, neuroinflammatory cells called microglia acquire different activation phenotypes. At the early stage of AD, activated microglia are mainly dominated by the neuroprotective and anti-inflammatory M2 phenotype. Conversely, in the later stage of AD, the excessive activation of microglia is considered detrimental and pro-inflammatory, turning into the M1 phenotype. Therapeutic strategies targeting the modulation of microglia may regulate their specific phenotype. Fortunately, with the rapid development of in vivo imaging methodologies, visualization of microglial activation has been well-explored. In this review, we summarize the critical role of activated microglia during the pathogenesis of AD and current studies concerning imaging of microglial activation in AD patients. We explore the possibilities for identifying activated microglial phenotypes with imaging techniques and highlight promising therapies that regulate the microglial phenotype in AD mice.

Umbilical Cord Mesenchymal Stem Cells Conditioned Medium Promotes Aβ25-35 phagocytosis by Modulating Autophagy and Aβ-Degrading Enzymes in BV2 Cells

Mesenchymal stem cell (MSC) therapy is a promising prospect for the treatment of Alzheimer's disease (AD); however, the underlying mechanisms by which MSCs mediate positive effects are still unclear. We speculated that MSCs mediate microglial autophagy and enhance the clearance of Aβ. To test this hypothesis, we cultured BV2 microglial cells with umbilical cord mesenchymal stem cells conditioned medium (ucMSCs-CM) in the presence or absence of Aβ25-35 oligomers. We investigated BV2 cell proliferation, cell death, and Aβ25-35 phagocytosis as well as protein expression levels of LC3, Beclin-1, p62, insulin-degrading enzyme (IDE), and neprilysin (Nep) with western blotting. The results showed that ucMSCs-CM inhibited the proliferation and decreased cell death of BV2 cells induced by Aβ25-35. ucMSCs-CM also promoted the phagocytosis of Aβ25-35 by BV2 cells and changed the expression of autophagy-related proteins LC3, Beclin-1, and p62. Treatment also upregulated the expression of Aβ-degrading enzymes IDE and Nep. Furthermore, the culture medium in BV2 cells with Aβ25-35 and ucMSCs-CM prevented neuronal cell SH-SY5Y from cell death compared to control medium without ucMSCs-CM. Altogether, these data suggested that ucMSCs-CM protect microglial and neuronal cells from Aβ25-35-induced cell death and promote Aβ phagocytosis by modulating autophagy and enhancing the expression of Aβ-degrading enzymes in microglia.

A stretchable conductive Polypyrrole Polydimethylsiloxane device fabricated by simple soft lithography and oxygen plasma treatment

This paper reports a simple method used to fabricate a stretchable conductive polypyrrole (PPy) rough pore-shape polydimethylsiloxane (p-PDMS) device. An abrasive paper is first used to imprint rough micro-structures on the SU-8 micromold. The p-PDMS microchannel is then fabricated using a standard soft-lithography process. An oxygen plasma treatment is then applied to form an irreversible sealing between the microchannel and a blank cover PDMS. The conductive layer is formed by injecting the PPy mixture into the microchannel which polymerizes in the rough pore-shape micro-structures; The PPy/p-PDMS hybrid device shows good electrical property and stretchability. The electrical properties of different geometrical designs of the PPy/p-PDMS microchannel under stretching were investigated, including straight, curved, and serpentine. Mouse embryonic fibroblasts (NIH/3 T3) were also cultured inside the PPy/p-PDMS device to demonstrate good biocompatibility and feasibility using the conductive and stretchable microchannel in cell culture microfluidics applications. Finally, cyclic stretching and bending tests were performed to evaluate the reliability of PPy/p-PDMS microchannel.

Post-Traumatic Stress Disorder Delineating the Progression and Underlying Mechanisms Following Blast Traumatic Brain Injury

Posttraumatic Stress Disorder (PTSD) is a devastating condition that can develop after blast Traumatic Brain Injury (TBI). Ongoing work has been performed to understand how PTSD develops after injury. In this review, we highlight how PTSD affects individuals, discuss what is known about the physiologic changes to the hypothalamic pituitary axis and neurotransmitter pathways, and present an overview of genetic components that may predispose individuals to developing PTSD. We then provide an overview of current treatment strategies to treat PTSD in veterans and present new strategies that may be useful going forward. The need for further clinical and pre-clinical studies is imperative to improve diagnosis, treatment, and management for patients that develop PTSD following blast TBI.

Cell reprogramming: Therapeutic potential and the promise of rejuvenation for the aging brain

Aging is associated with a progressive increase in the incidence of neurodegenerative diseases, with Alzheimer's (AD) and Parkinson's (PD) disease being the most conspicuous examples. Within this context, the absence of efficacious therapies for most age-related brain pathologies has increased the interest in regenerative medicine. In particular, cell reprogramming technologies have ushered in the era of personalized therapies that not only show a significant potential for the treatment of neurodegenerative diseases but also promise to make biological rejuvenation feasible. We will first review recent evidence supporting the emerging view that aging is a reversible epigenetic phenomenon. Next, we will describe novel reprogramming approaches that overcome some of the intrinsic limitations of conventional induced-pluripotent-stem-cell technology. One of the alternative approaches, lineage reprogramming, consists of the direct conversion of one adult cell type into another by transgenic expression of multiple lineage-specific transcription factors (TF). Another strategy, termed pluripotency factor-mediated direct reprogramming, uses universal TF to generate epigenetically unstable intermediates able to differentiate into somatic cell types in response to specific differentiation factors. In the third part we will review studies showing the potential relevance of the above approaches for the treatment of AD and PD.

Amniotic Mesenchymal Stem Cells Decrease Aβ Deposition and Improve Memory in APP/PS1 Transgenic Mice

Transplantation of human amniotic mesenchymal stem cells (hAM-MSCs) seems to be a promising strategy for the treatment of neurodegenerative disorders, including Alzheimer's disease (AD). However, the clinical therapeutic effects of hAM-MSCs and their mechanisms of action in AD remain to be determined. Here, we used amyloid precursor protein (APP) and presenilin1 (PS1) double-transgenic mice to evaluate the effects of hAM-MSC transplantation on AD-related neuropathology and cognitive dysfunction. We found that hAM-MSC transplantation into the hippocampus dramatically reduced amyloid-β peptide (Aβ) deposition and rescued spatial learning and memory deficits in APP/PS1 mice. Interestingly, these effects were associated with increasing in Aβ-degrading factors, elevations in activated microglia, and the modulation of neuroinflammation. Furthermore, enhanced hippocampal neurogenesis in the subgranular zone (SGZ) of the dentate gyrus (DG) and enhanced synaptic plasticity following hAM-MSC treatment could be another important factor in reversing the cognitive decline in APP/PS1 mice. Instead, the mechanism underlying the improved cognition apparently involves a robust increase in hippocampal synaptic density and neurogenesis that is mediated by brain-derived neurotrophic factor (BDNF). In conclusion, our data suggest that hAM-MSCs may be a new and effective therapy for the treatment of AD.