The prospective role of mesenchymal stem cells exosomes on circumvallate taste buds in induced Alzheimer's disease of ovariectomized albino rats: (Light and transmission electron microscopic study)

Regenerative potentials of bone marrow mesenchymal stem cells derived exosomes or its combination with zinc in recovery of degenerated circumvallate papilla following surgical bilateral transection of glossopharyngeal nerve in rats

BACKGROUND

Taste buds' innervation is necessary to sustain their cell turnover, differentiated taste buds and nerve fibers in circumvallate papilla (CVP) disappear following glossopharyngeal nerve transection. Normally, taste buds recover to baseline number in about 70 days. Bone marrow stem cell (BM-MSC) derived exosomes or their combination with Zinc chloride are used to assess their potential to speed up the regeneration process of CVP following bilateral deafferentation.

METHODS

Twenty-eight male Sprague-Dawley rats were randomly divided into four groups; Group I: subjected to sham operation followed by IP injection of saline. The other experimental groups (II, III and IV) were subjected to surgical bilateral transection of glossopharyngeal nerve. Group II received single IP injection of saline. Group III received single IV injection of BM-MSC-derived exosomes (100 µg). Group IV received single IV injection of BM-MSC-derived exosomes and single IP injection of zinc chloride (5 mg/kg). After 28 days, CVP was dissected and prepared for histological and histomorphometric analysis, RT-PCR for cytokeratin 8 gene expression, ELISA to assess protein level of brain-derived neurotrophic factor, redox state analysis of malondialdehyde and glutathione content, followed by statistical analysis.

RESULTS

Histopathologically, group II exhibited great tissue damage with marked reduction in taste buds and signs of degeneration in the remaining ones. Group III was close to control group with marked improvement in taste buds' number and structure. Group IV showed inferior results when compared to group III, with many immature taste buds and signs of degeneration. Statistical results showed that groups I and III have significantly higher values than groups II and IV regarding taste buds' number, cytokeratin 8, and reduced glutathione. However, malondialdehyde demonstrated high significant values in group IV compared to groups I and III. Regarding brain-derived neurotrophic factor, group III had significantly higher values than group II.

CONCLUSION

BM-MSC-derived exosomes have superior regenerative potentials in acceleration of CVP and nerve healing following bilateral transection of glossopharyngeal nerve in contrary to its combination with zinc chloride.

Locally injected bone marrow-derived mesenchymal stem cells reverts the histopathological changes in the tongue of carbimazole-induced hypothyroidism of male rats

OBJECTIVE

To decipher the role of locally injected bone marrow mesenchymal stem cells (BM-MSCs) in the tongue of hypothyroid rats.

DESIGN

A total 24 male Wister rats were utilized and allocated into 3 groups (n = 8). As for the control group, rats received distilled water via oral gavage. In the hypothyroid group, rats administered carbimazole 5 mg/ 250 g/ day for 6 successive weeks, for hypothyroidism induction. The BM-MSC treated hypothyroid group (BM-MSC group); hypothyroid rats received local injection of 0.5 million BM-MSCs in tongue. Six weeks after BM-MSC injection, tongue samples were processed for Hematoxylin and eosin (H and E) staining, Ki67-immunohistochemistry and histomorphometric analysis.

RESULTS

The hypothyroid group revealed degenerative alterations in the lingual papillae, and apparent thinning of the inferior lingual epithelium compared to their controls. Tongues of the BM-MSC group depicted restoration of the normal tongue histology. The Ki67 immunoreaction was apparently decreased in the lingual epithelium of hypothyroid group compared to their controls, however the BM-MSC group regained Ki67 immunostaining.

CONCLUSION

Our data suggest that administration of BM-MSCs rescued the degenerative changes in the lingual mucosa and one of the possible underlying mechanisms could be the restoration of cellular proliferation in the lingual epithelium.

Phosphorylated Tau in the Taste Buds of Alzheimer's Disease Mouse Models

Numerous systemic diseases manifest with oral symptoms and signs. The molecular diagnosis of Alzheimer's disease (AD), the most prevalent neurodegenerative disease worldwide, currently relies on invasive or expensive methods, emphasizing the imperative for easily accessible biomarkers. In this study, we explored the expression patterns of key proteins implicated in AD pathophysiology within the taste buds of mice. We detected the expression of amyloid precursor protein (APP) and tau protein in the taste buds of normal C57BL/6 mice. Phosphorylated tau was predominantly found in type II and III taste cells, while APP was located in type I taste cells. Remarkably, we observed significantly stronger immunoreactivity to phosphorylated tau in the taste buds of aged AD mouse models compared to age-matched controls. These findings underscore the oral expression of biomarkers associated with AD, highlighting the diagnostic potential of the oral cavity for neurodegenerative diseases.

Mesenchymal stromal cell-derived secretome-based therapy for neurodegenerative diseases: overview of clinical trials

BACKGROUND

Over the past few years, mesenchymal stromal cells (MSCs) have attracted a great deal of scientific attention owing to their promising results in the treatment of incurable diseases. However, there are several concerns about their possible side effects after direct cell transplantation, including host immune response, time-consuming cell culture procedures, and the dependence of cell quality on the donor, which limit the application of MSCs in clinical trials. On the other hand, it is well accepted that the beneficial effects of MSCs are mediated by secretome rather than cell replacement. MSC secretome refers to a variety of bioactive molecules involved in different biological processes, specifically neuro-regeneration.

MAIN BODY

Due to the limited ability of the central nervous system to compensate for neuronal loss and relieve disease progress, mesenchymal stem cell products may be used as a potential cure for central nervous system disorders. In the present study, the therapeutic effects of MSC secretome were reviewed and discussed the possible mechanisms in the three most prevalent central nervous system disorders, namely Alzheimer's disease, multiple sclerosis, and Parkinson's disease. The current work aimed to help discover new medicine for the mentioned complications.

CONCLUSION

The use of MSC-derived secretomes in the treatment of the mentioned diseases has encouraging results, so it can be considered as a treatment option for which no treatment has been introduced so far.

New frontiers of oral sciences: Focus on the source and biomedical application of extracellular vesicles

Extracellular vesicles (EVs) are a class of nanoparticles that are derived from almost any type of cell in the organism tested thus far and are present in all body fluids. With the capacity to transfer "functional cargo and biological information" to regulate local and distant intercellular communication, EVs have developed into an attractive focus of research for various physiological and pathological conditions. The oral cavity is a special organ of the human body. It includes multiple types of tissue, and it is also the beginning of the digestive tract. Moreover, the oral cavity harbors thousands of bacteria. The importance and particularity of oral function indicate that EVs derived from oral cavity are quite complex but promising for further research. This review will discuss the extensive source of EVs in the oral cavity, including both cell sources and cell-independent sources. Besides, accumulating evidence supports extensive biomedical applications of extracellular vesicles in oral tissue regeneration and development, diagnosis and treatment of head and neck tumors, diagnosis and therapy of systemic disease, drug delivery, and horizontal gene transfer (HGT). The immune cell source, odontoblasts and ameloblasts sources, diet source and the application of EVs in tooth development and HGT were reviewed for the first time. In conclusion, we concentrate on the extensive source and potential applications offered by these nanovesicles in oral science.

Mesenchymal Stem Cell-Derived Extracellular Vesicles as Proposed Therapy in a Rat Model of Cerebral Small Vessel Disease

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have been employed in the past decade as therapeutic agents in various diseases, including central nervous system (CNS) disorders. We currently aimed to use MSC-EVs as potential treatment for cerebral small vessel disease (CSVD), a complex disorder with a variety of manifestations. MSC-EVs were intranasally administrated to salt-sensitive hypertension prone SBH/y rats that were DOCA-salt loaded (SBH/y-DS), which we have previously shown is a model of CSVD. MSC-EVs accumulated within brain lesion sites of SBH/y-DS. An in vitro model of an inflammatory environment in the brain demonstrated anti-inflammatory properties of MSC-EVs. Following in vivo MSC-EV treatment, gene set enrichment analysis (GSEA) of SBH/y-DS cortices revealed downregulation of immune system response-related gene sets. In addition, MSC-EVs downregulated gene sets related to apoptosis, wound healing and coagulation, and upregulated gene sets associated with synaptic signaling and cognition. While no specific gene was markedly altered upon treatment, the synergistic effect of all gene alternations was sufficient to increase animal survival and improve the neurological state of affected SBH/y-DS rats. Our data suggest MSC-EVs act as microenvironment modulators, through various molecular pathways. We conclude that MSC-EVs may serve as beneficial therapeutic measure for multifactorial disorders, such as CSVD.

Emerging role of mesenchymal stromal cells (MSCs)-derived exosome in neurodegeneration-associated conditions: a groundbreaking cell-free approach

Accumulating proofs signify that pleiotropic effects of mesenchymal stromal cells (MSCs) are not allied to their differentiation competencies but rather are mediated mainly by the releases of soluble paracrine mediators, making them a reasonable therapeutic option to enable damaged tissue repair. Due to their unique immunomodulatory and regenerative attributes, the MSC-derived exosomes hold great potential to treat neurodegeneration-associated neurological diseases. Exosome treatment circumvents drawbacks regarding the direct administration of MSCs, such as tumor formation or reduced infiltration and migration to brain tissue. Noteworthy, MSCs-derived exosomes can cross the blood-brain barrier (BBB) and then efficiently deliver their cargo (e.g., protein, miRNAs, lipid, and mRNA) to damaged brain tissue. These biomolecules influence various biological processes (e.g., survival, proliferation, migration, etc.) in neurons, oligodendrocytes, and astrocytes. Various studies have shown that the systemic or local administration of MSCs-derived exosome could lead to the favored outcome in animals with neurodegeneration-associated disease mainly by supporting BBB integrity, eliciting pro-angiogenic effects, attenuating neuroinflammation, and promoting neurogenesis in vivo. In the present review, we will deliver an overview of the therapeutic benefits of MSCs-derived exosome therapy to ameliorate the pathological symptoms of acute and chronic neurodegenerative disease. Also, the underlying mechanism behind these favored effects has been elucidated.

Therapeutic utility of mesenchymal stromal cell (MSC)-based approaches in chronic neurodegeneration: a glimpse into underlying mechanisms, current status, and prospects

Recently, mesenchymal stromal cell (MSC)-based therapy has become an appreciated therapeutic approach in the context of neurodegenerative disease therapy. Accordingly, a myriad of studies in animal models and also some clinical trials have evinced the safety, feasibility, and efficacy of MSC transplantation in neurodegenerative conditions, most importantly in Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), and Huntington’s disease (HD). The MSC-mediated desired effect is mainly a result of secretion of immunomodulatory factors in association with release of various neurotrophic factors (NTFs), such as glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF). Thanks to the secretion of protein-degrading molecules, MSC therapy mainly brings about the degradation of pathogenic protein aggregates, which is a typical appearance of chronic neurodegenerative disease. Such molecules, in turn, diminish neuroinflammation and simultaneously enable neuroprotection, thereby alleviating disease pathological symptoms and leading to cognitive and functional recovery. Also, MSC differentiation into neural-like cells in vivo has partially been evidenced. Herein, we focus on the therapeutic merits of MSCs and also their derivative exosome as an innovative cell-free approach in AD, HD, PD, and ALS conditions. Also, we give a brief glimpse into novel approaches to potentiate MSC-induced therapeutic merits in such disorders, most importantly, administration of preconditioned MSCs.

Exosomes Derived from Bone Marrow Mesenchymal Stem Cells (BMSC) Inhibit Apoptosis Factors Caspase-3 and Caspase-9 to Promote the Repair of Cardiomyocytes

This study assesses the effect of exosomes derived from bone marrow mesenchymal stem cells (MSCs) on cardiomyocytes by inhibiting the apoptotic factors Caspase-3 and Caspase-9. Cell purity was evaluated under a microscope and exosomes were obtained by ultracentrifugation from the culture supernatant of BMSCs. Tunable resistive pulse sensing (TRPS) method analyzed the concentration distribution of exosomes particle size, and specific surface antigens were examined by flow cytometry. Exosomes were used to process cardiomyocytes to detect cardiomyocyte repair. After plasmid interference technology, the effect of exosomes on caspase-3 and caspase-9 expression was detected by western blot. The activity of cardiomyocytes was analyzed by CCK-8. Exosomes can promote the viability of cardiomyocytes. The mRNA and protein levels of GLUT3 in cardiomyocytes were significantly increased. Exosomes can inhibit cardiomyocyte apoptosis by down-regulating the expression of apoptosis-related proteins. Exosomes can improve the function and promote the repair of myocardium by inhibiting the expression of apoptotic factors Caspase-3 and Caspase-9.

Edaravone Protects Nerve Synapse Damage in Alzheimer’s Disease via Regulating Rho (Ras Homologue)/Rho-Associated Protein Kinase (Rho/ROCK) Pathway

Edaravone regulates Rho/ROCK signaling pathway and its relationship with Alzheimer’s disease (AD) damage repair remains unclear. Our study aims to explore the protective mechanism of edar-avone on Alzheimer Disease nerve synapses. The Alzheimer Disease animal mouse model was established followed by analysis of hippocampal synaptic damage by Congo red stain and Golgi’s method, Morris water maze assay, levels of postsynaptic density mRNA 95 antibody (PSD95) and synapse-associated mRNA synapsin 1 (SYN1) in the hippocampus. Edaravone can improve the behavior of mice, including spatial learning and memory, and reduce senile plaques in the cerebral cortex of APP/PS1 mice. Edaravone can upregulate the expression of synapse-related mRNA SYN1 and PSD95 in the hippocampus of APP/PS1 mice and inhibit Rho and ROCK mRNA level. Edaravone targets the Rho/ROCK pathway to protect Alzheimer Disease nerve synapse damage, indicating that the Rho/ROCK pathway may be a key link in the effect of edaravone.

Promising Opportunities for Treating Neurodegenerative Diseases with Mesenchymal Stem Cell-Derived Exosomes

Neurodegenerative disease refers to any pathological condition in which there is a progressive decline in neuronal function resulting from brain atrophy. Despite the immense efforts invested over recent decades in developing treatments for neurodegenerative diseases, effective therapy for these conditions is still an unmet need. One of the promising options for promoting brain recovery and regeneration is mesenchymal stem cell (MSC) transplantation. The therapeutic effect of MSCs is thought to be mediated by their secretome, and specifically, by their exosomes. Research shows that MSC-derived exosomes retain some of the characteristics of their parent MSCs, such as immune system modulation, regulation of neurite outgrowth, promotion of angiogenesis, and the ability to repair damaged tissue. Here, we summarize the functional outcomes observed in animal models of neurodegenerative diseases following MSC-derived exosome treatment. We will examine the proposed mechanisms of action through which MSC-derived exosomes mediate their therapeutic effects and review advanced studies that attempt to enhance the improvement achieved using MSC-derived exosome treatment, with a view towards future clinical use.