Systemic transplantation of mesenchymal stem cells can reduce cognitive and motor deficits in rats with unilateral lesions of the neostriatum

Stem Cells and Natural Agents in the Management of Neurodegenerative Diseases: A New Approach

Neurodegenerative diseases refer to a group of neurological disorders as a consequence of various destructive illnesses, that predominantly impact neurons in the central nervous system, resulting in impairments in certain brain functions. Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, and other neurodegenerative disorders represent a major risk to human health. In order to optimize structural and functional recovery, reconstructive methods integrate many approaches now, to address the complex and multivariate pathophysiology of neurodegenerative disorders. Stem cells, with their unique property of regeneration, offer new possibilities in regenerative and reconstructive medicine. Concurrently, there is an important role for natural products in controlling many health sufferings and they can delay or even prevent the onset of various diseases. In addition, due to their therapeutic properties, they have been used as neuroprotective agents to treat neurodegenerative disorders. After decades of intensive research, scientists made advances in treating these disorders so far, but current therapies are still not capable of preventing the illnesses from progressing. Therefore, in this review, we focused on a new perspective combining stem cells and natural products as an innovative therapy option in the management of neurodegenerative diseases.

Mesenchymal Stem Cell Therapy for Huntington Disease: A Meta-Analysis

Objective

Mesenchymal stem cell (MSC) therapy has been explored in Huntington disease (HD) as a potential therapeutic approach; however, a complete synthesis of these results is lacking. We conducted a meta-analysis to evaluate the effects of MSCs on HD.

Method

Eligible studies published before November 2022 were screened from Embase, PubMed, Web of Science, Medline, and Cochrane in accordance with PRISMA guidelines. ClinicalTrial.gov and the World Health Organization International Clinical Trials Registry Platform were also searched for registered clinical trials. The outcomes in rodent studies evaluated included morphological changes (striatal volume and ventricular volume), motor function (rotarod test, wire hang test, grip strength test, limb-clasping test, apomorphine-induced rotation test, and neuromuscular electromyography activity), cognition (Morris water maze test), and body weight.

Result

The initial search returned 362 records, of which 15 studies incorporating 346 HD rodents were eligible for meta-analysis. Larger striatal and smaller ventricular volumes were observed in MSC-treated animals compared to controls. MSCs transplanted before the occurrence of motor dysfunction rescued the motor incoordination of HD. Among different MSC sources, bone marrow mesenchymal stem cells were the most investigated cells and were effective in improving motor coordination. MSC therapy improved muscle strength, neuromuscular electromyography activity, cortex-related motor function, and striatum-related motor function, while cognition was not changed. The body weight of male HD rodents increased after MSC transplantation, while that of females was not affected.

Conclusion

Meta-analysis showed a positive effect of MSCs on HD rodents overall, as reflected in morphological changes, motor coordination, muscle strength, neuromuscular electromyography activity, cortex-related motor function, and striatum-related motor function, while cognition was not changed by MSC therapy.

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.

'Real-life' hippocampal-dependent spatial memory impairments in Huntington's disease

Hippocampal-dependent spatial memory impairments are seen in Huntington's disease animal models. Similar impairments were recently reported in Huntington's disease participants on analogous spatial memory tasks (e.g., virtual Morris Water Maze), however, these tasks do not translate well to the range of functions involved in day-to-day spatial cognition. In this study we examined 'real-life' hippocampal-dependent spatial memory in Huntington's disease participants. We studied premanifest Huntington's disease (N = 24), early manifest Huntington's disease (N = 14), and matched healthy controls (N = 33) with a virtual environment, which demanded spatial memory function on three levels: navigation, object location, and plan drawing. To examine the case for hippocampal-dependent spatial memory more closely, we compared the performance of our Huntington's disease participants to that of a group of temporal lobe epilepsy patients (N = 30) who were previously tested on the virtual environment. Spatial memory performance was also compared to two common neuropsychological tests of spatial cognition, the Paired Associates Learning from the Cambridge Neuropsychological Automated Test Battery, and the Rey-Osterrieth Complex Figure Test. People with early manifest Huntington's disease were impaired across all spatial memory tasks. Premanifest Huntington's disease participants were most notably impaired on the object location measure of the virtual environment, which is heavily dependent on hippocampal function, but showed no such impairments on the Paired Associates Learning or the Rey-Osterrieth Complex Figure Test. Object location memory and navigation performance did not differ between people with Huntington's disease and temporal lobe epilepsy. Aligned with studies in Huntington's disease animal models, 'real-life' spatial memory is impaired in people with Huntington's disease prior to clinical diagnosis. This alignment has important implications for testing treatments for Huntington's disease. From the standpoint of neurodegeneration, the dependence of our spatial memory measures on hippocampal function extends the focus of cognitive assessment research in Huntington's disease beyond its primary pathology within the striato-frontal circuit.

Regenerative medicine in Huntington's disease: Strengths and weaknesses of preclinical studies

Huntington's disease (HD) is an inherited neurodegenerative disorder, characterized by impairment in motor, cognitive and psychiatric domains. Currently, there is no specific therapy to act on the onset or progression of HD. The marked neuronal death observed in HD is a main argument in favour of stem cells (SCs) transplantation as a promising therapeutic perspective to replace the population of lost neurons and restore the functionality of the damaged circuitry. The availability of rodent models of HD encourages the investigation of the restorative potential of SCs transplantation longitudinally. However, the results of preclinical studies on SCs therapy in HD are so far largely inconsistent; this hampers the individuation of the more appropriate model and precludes the comparative analysis of transplant efficacy on behavioural end points. Thus, this review will describe the state of the art of in vivo research on SCs therapy in HD, analysing in a translational perspective the strengths and weaknesses of animal studies investigating the therapeutic potential of cell transplantation on HD progression.

Human Mesenchymal Stem Cells Genetically Engineered to Overexpress Brain-derived Neurotrophic Factor Improve Outcomes in Huntington's Disease Mouse Models

Huntington's disease (HD) is a fatal degenerative autosomal dominant neuropsychiatric disease that causes neuronal death and is characterized by progressive striatal and then widespread brain atrophy. Brain-derived neurotrophic factor (BDNF) is a lead candidate for the treatment of HD, as it has been shown to prevent cell death and to stimulate the growth and migration of new neurons in the brain in transgenic mouse models. BDNF levels are reduced in HD postmortem human brain. Previous studies have shown efficacy of mesenchymal stem/stromal cells (MSC)/BDNF using murine MSCs, and the present study used human MSCs to advance the therapeutic potential of the MSC/BDNF platform for clinical application. Double-blinded studies were performed to examine the effects of intrastriatally transplanted human MSC/BDNF on disease progression in two strains of immune-suppressed HD transgenic mice: YAC128 and R6/2. MSC/BDNF treatment decreased striatal atrophy in YAC128 mice. MSC/BDNF treatment also significantly reduced anxiety as measured in the open-field assay. Both MSC and MSC/BDNF treatments induced a significant increase in neurogenesis-like activity in R6/2 mice. MSC/BDNF treatment also increased the mean lifespan of the R6/2 mice. Our genetically modified MSC/BDNF cells set a precedent for stem cell-based neurotherapeutics and could potentially be modified for other neurodegenerative disorders such as amyotrophic lateral sclerosis, Alzheimer's disease, and some forms of Parkinson's disease. These cells provide a platform delivery system for future studies involving corrective gene-editing strategies.

Stem cell models of polyglutamine diseases and their use in cell-based therapies

Polyglutamine diseases are fatal neurological disorders that affect the central nervous system. They are caused by mutations in disease genes that contain CAG trinucleotide expansions in their coding regions. These mutations are translated into expanded glutamine chains in pathological proteins. Mutant proteins induce cytotoxicity, form intranuclear aggregates and cause neuronal cell death in specific brain regions. At the moment there is no cure for these diseases and only symptomatic treatments are available. Here, we discuss novel therapeutic approaches that aim in neuronal cell replacement using induced pluripotent or adult stem cells. Additionally, we present the beneficial effect of genetically engineered mesenchymal stem cells and their use as disease models or RNAi/gene delivery vehicles. In combination with their paracrine and cell-trophic properties, such cells may prove useful for the development of novel therapies against polyglutamine diseases.

Reductions in behavioral deficits and neuropathology in the R6/2 mouse model of Huntington's disease following transplantation of bone-marrow-derived mesenchymal stem cells is dependent on passage number

Introduction

Huntington’s disease (HD) is an autosomal dominant disorder caused by an expanded CAG repeat (greater than 38) on the short arm of chromosome 4, resulting in loss and dysfunction of neurons in the neostriatum and cortex, leading to cognitive decline, motor dysfunction, and death, typically occurring 15 to 20 years after the onset of motor symptoms. Although an effective treatment for HD has remained elusive, current studies using transplants of bone-marrow-derived mesenchymal stem cells provides considerable promise. This study further investigates the efficacy of these transplants with a focus on comparing how passage number of these cells may affect subsequent efficacy following transplantation.

Methods

In this study, mesenchymal stem cells isolated from the bone-marrow of mice (BM MSCs), were labeled with Hoechst after low (3 to 8) or high (40 to 50) numbers of passages and then transplanted intrastriatally into 5-week-old R6/2 mice, which carries the N-terminal fragment of the human HD gene (145 to 155 repeats) and rapidly develops symptoms analogous to the human form of the disease.

Results

It was observed that the transplanted cells survived and the R6/2 mice displayed significant behavioral and morphological sparing compared to untreated R6/2 mice, with R6/2 mice receiving high passage BM MSCs displaying fewer deficits than those receiving low-passage BM MSCs. These beneficial effects are likely due to trophic support, as an increase in brain derived neurotrophic factor mRNA expression was observed in the striatum following transplantation of BM MSCs.

Conclusion

The results from this study demonstrate that BM MSCs hold significant therapeutic value for HD, and that the amount of time the cells are exposed to in vitro culture conditions can alter their efficacy.

Developing stem cell therapies for juvenile and adult-onset Huntington's disease

Stem cell therapies have been explored as a new avenue for the treatment of neurologic disease and damage within the CNS in part due to their native ability to mimic repair mechanisms in the brain. Mesenchymal stem cells have been of particular clinical interest due to their ability to release beneficial neurotrophic factors and their ability to foster a neuroprotective microenviroment. While early stem cell transplantation therapies have been fraught with technical and political concerns as well as limited clinical benefits, mesenchymal stem cell therapies have been shown to be clinically beneficial and derivable from nonembryonic, adult sources. The focus of this review will be on emerging and extant stem cell therapies for juvenile and adult-onset Huntington's disease.

Scaffolds derived from cancellous bovine bone support mesenchymal stem cells' maintenance and growth

Since bone defects can lead to various disabilities, in recent years, many increasing attempts have been made in bone tissue engineering. In this regard, scaffolds have attracted a lot of attention as three dimensional substrates for cell attachment which improve successful tissue engineering. The aim of the present study was to provide an interconnected porous scaffold to facilitate cell infiltration. To do so, cancellous bone from bovine femur was dissected in fragments and decellularized by physicochemical methods, including snap freeze/thaw, rinsing in hot water and treatment with different solutions of sodium dodecyl sulfate (SDS). Histological analysis and 4',6-diamidino-2-phenylindole staining revealed that the best results were obtained after treatment with 2.5%, 5%, and 8% SDS for 8, 3, or 1 h respectively, which significantly removed bone cells with intact trabeculae geometry. Further characterization of decellularized scaffolds by the compression tests also revealed no significant difference between elastic modulus values of the three different SDS treatments. Moreover, studying the ratio of bone trabeculae to bone surfaces (BT/BS) as assessed by Clemex vision software 3.5 showed that treatment with 2.5% SDS for 8 h resulted in a BT/BS score in the range of native bone and therefore this treatment was used for further experiments. Histological studies and scanning electron microscopy revealed rat mesenchymal stem cells integration, adhesion, and maintenance during the 2 and 7 d of culture in vitro. In conclusion, the present results support the effective role of SDS in cancellous bovine bone decellularization and also propensity of treated samples in providing a suitable three-dimentional environment to support the maintenance and growth of mesenchymal stem cells.

Transdifferentiation: a cell and molecular reprogramming process

Evidence has emerged recently indicating that differentiation is not entirely a one-way process, and that it is possible to convert one cell type to another, both in vitro and in vivo. This phenomenon is called transdifferentiation, and is generally defined as the stable switch of one cell type to another. Transdifferentiation plays critical roles during development and in regeneration pathways in nature. Although this phenomenon occurs rarely in nature, recent studies have been focused on transdifferentiation and the reprogramming ability of cells to produce specific cells with new phenotypes for use in cell therapy and regenerative medicine. Thus, understanding the principles and the mechanism of this process is important for producing desired cell types. Here some well-documented examples of transdifferentiation, and their significance in development and regeneration are reviewed. In addition, transdifferentiation pathways are considered and their potential molecular mechanisms, especially the role of master switch genes, are considered. Finally, the significance of transdifferentiation in regenerative medicine is discussed.

Neuroprotective effects of mesenchymal stem cell transplantation in animal model of cerebellar degeneration

BACKGROUND

The cerebellum has been considered a key structure for the processes involved in sensorimotor integration ultimately leading to motor planning and execution of coordinated movement. Thus, motor deficits and behavioral changes can be associated with cerebellar degeneration.

METHODS

Here, the chemical neurotoxin pyridine-2,3-dicarboxylic acid (quinolinic acid, QA) used to create partially cerebellar degeneration in adult Wistar rats suitable for use in stem cell transplantation studies. Stereotaxicaly administration of QA (0.2 mmol) in the right cerebellar hemisphere (folia VI) caused noticeable motor disturbance in all treated animals. Forty-eights hours after causing lesion, rat bone marrow-derived mesenchymal stem cells (MSCs) were transplanted into damaged cerebellar hemisphere. We investigated the role of MSC transplantation in forms of motor and non-motor learning that involves the cerebellum and its neuroprotective effects in Purkinje cells loss.

RESULTS

CM-Dil labeling showed that the transplanted MSCs survived and migrated in the cerebellum 6 weeks after transplantation. The MSC-transplanted group showed markedly improved functional performance on the rotating rod test (P≤0.0001) and beam walking test (P≤0.0001) during 6 weeks compared with the controls. For non-motor learning, we used passive avoidance learning test in 3 weeks after transplantation. The results showed that MSC transplantation prevented the development of memory deficit caused by cerebellar degeneration (P≤0.001). Stereological analysis in 6 weeks after transplantation showed that QA significantly decreases Purkinje cells in vehicle-treated rats and MSC transplantation is neuroprotective and decreases Purkinje cell loss in MSC-treated rats (P≤0.0001).

CONCLUSION

The results indicate that transplantation of MSCs can significantly reduce the behavioral and neuroanatomical abnormalities of these animals during 6 weeks after engraftment. According to results of this assay, cell therapy by means of bone marrow-derived adult stem cells promises for treatment of cerebellar diseases.

Evaluating the biodegradability of Gelatin/Siloxane/Hydroxyapatite (GS-Hyd) complex in vivo and its ability for adhesion and proliferation of rat bone marrow mesenchymal stem cells

Recent studies have shown that the use of biomaterials and new biodegradable scaffolds for repair or regeneration of damaged tissues is of vital importance. Scaffolds used in tissue engineering should be biodegradable materials with three-dimensional structures which guide the growth and differentiation of the cells. They also tune physical, chemical and biological properties for efficient supplying of the cells to the selected tissues and have proper porosity along with minimal toxic effects. In this manner, the study of these characteristics is a giant stride towards scaffold design. In this study, Gelatin/Siloxane/Hydroxyapatite (GS-Hyd) scaffold was synthesized and its morphology, in vivo biodegradability, cytotoxic effects and ability for cell adhesion were investigated using mesenchymal stem cells (MSCs). The cells were treated with different volumes of the scaffold suspension for evaluation of its cytotoxic effects. The MSCs were also seeded on scaffolds and cultured for 2 weeks to evaluate the ability of the scaffold in promoting of cell adhesion and growth. To check the biodegradability of the scaffold in vivo, scaffolds were placed in the rat body for 21 days in three different positions of thigh muscle, testicle, and liver and they were analyzed by scanning electron microscopy (SEM) and weight changes. According to the results of the viability of this study, no cytotoxic effects of GS-Hyd scaffold was found on the cells and MSCs could adhere on the scaffold with expanding their elongations and forming colonies. The rate of degradation as assessed by weight loss was significant within each group along with significant differences between different tissues at the same time point. SEM micrographs also indicated the obvious morphological changes on the surface of the particles and diameter of the pores through different stages of implantation. The greatest amount of degradation happened to the scaffold particles implanted into the muscle, followed by testicle and liver, respectively.

Genetically engineered mesenchymal stem cells as a proposed therapeutic for Huntington's disease

There is much interest in the use of mesenchymal stem cells/marrow stromal cells (MSC) to treat neurodegenerative disorders, in particular those that are fatal and difficult to treat, such as Huntington's disease. MSC present a promising tool for cell therapy and are currently being tested in FDA-approved phase I-III clinical trials for many disorders. In preclinical studies of neurodegenerative disorders, MSC have demonstrated efficacy, when used as delivery vehicles for neural growth factors. A number of investigators have examined the potential benefits of innate MSC-secreted trophic support and augmented growth factors to support injured neurons. These include overexpression of brain-derived neurotrophic factor and glial-derived neurotrophic factor, using genetically engineered MSC as a vehicle to deliver the cytokines directly into the microenvironment. Proposed regenerative approaches to neurological diseases using MSC include cell therapies in which cells are delivered via intracerebral or intrathecal injection. Upon transplantation, MSC in the brain promote endogenous neuronal growth, encourage synaptic connection from damaged neurons, decrease apoptosis, reduce levels of free radicals, and regulate inflammation. These abilities are primarily modulated through paracrine actions. Clinical trials for MSC injection into the central nervous system to treat amyotrophic lateral sclerosis, traumatic brain injury, and stroke are currently ongoing. The current data in support of applying MSC-based cellular therapies to the treatment of Huntington's disease is discussed.

Review paper: Critical Issues in Tissue Engineering: Biomaterials, Cell Sources, Angiogenesis, and Drug Delivery Systems

Tissue engineering is a newly emerging biomedical technology, which aids and increases the repair and regeneration of deficient and injured tissues. It employs the principles from the fields of materials science, cell biology, transplantation, and engineering in an effort to treat or replace damaged tissues. Tissue engineering and development of complex tissues or organs, such as heart, muscle, kidney, liver, and lung, are still a distant milestone in twenty-first century. Generally, there are four main challenges in tissue engineering which need optimization. These include biomaterials, cell sources, vascularization of engineered tissues, and design of drug delivery systems. Biomaterials and cell sources should be specific for the engineering of each tissue or organ. On the other hand, angiogenesis is required not only for the treatment of a variety of ischemic conditions, but it is also a critical component of virtually all tissue-engineering strategies. Therefore, controlling the dose, location, and duration of releasing angiogenic factors via polymeric delivery systems, in order to ultimately better mimic the stem cell niche through scaffolds, will dictate the utility of a variety of biomaterials in tissue regeneration. This review focuses on the use of polymeric vehicles that are made of synthetic and/or natural biomaterials as scaffolds for three-dimensional cell cultures and for locally delivering the inductive growth factors in various formats to provide a method of controlled, localized delivery for the desired time frame and for vascularized tissue-engineering therapies.

Human mesenchymal stem cells prolong survival and ameliorate motor deficit through trophic support in Huntington's disease mouse models

We investigated the therapeutic potential of human bone marrow-derived mesenchymal stem cells (hBM-MSCs) in Huntington's disease (HD) mouse models. Ten weeks after intrastriatal injection of quinolinic acid (QA), mice that received hBM-MSC transplantation showed a significant reduction in motor function impairment and increased survival rate. Transplanted hBM-MSCs were capable of survival, and inducing neural proliferation and differentiation in the QA-lesioned striatum. In addition, the transplanted hBM-MSCs induced microglia, neuroblasts and bone marrow-derived cells to migrate into the QA-lesioned region. Similar results were obtained in R6/2-J2, a genetically-modified animal model of HD, except for the improvement of motor function. After hBM-MSC transplantation, the transplanted hBM-MSCs may integrate with the host cells and increase the levels of laminin, Von Willebrand Factor (VWF), stromal cell-derived factor-1 (SDF-1), and the SDF-1 receptor Cxcr4. The p-Erk1/2 expression was increased while Bax and caspase-3 levels were decreased after hBM-MSC transplantation suggesting that the reduced level of apoptosis after hBM-MSC transplantation was of benefit to the QA-lesioned mice. Our data suggest that hBM-MSCs have neural differentiation improvement potential, neurotrophic support capability and an anti-apoptotic effect, and may be a feasible candidate for HD therapy.

Bone marrow derived mesenchymal stem cell transplantation in cerebellar degeneration: a behavioral study

In addition to its key role in complex motor function, the cerebellum is increasingly recognized to have a role in cognition. Thus, motor and cognitive deficits can be associated with cerebellar degeneration. After unilateral lesion in cerebellum (folia VI) was caused by Quinolinic acid, CM-DiI labeled mesenchymal stem cells (MSCs), which were isolated and purified from bone marrow, were transplanted into the damaged folium. Motor function was assessed using the cylinder test, rotarod, hanging wire and beam balance during 6 weeks after transplantation. Cognitive function was assessed using the Morris water maze learning paradigm in 3 weeks after transplantation. Six weeks after transplantation surviving MSCs were detectable in QA-treated animals. The MSC-transplanted group showed markedly improved functional performance in spatial memory, motor learning, locomotor asymmetry, dysmetria, abnormality in neuromuscular strength and equilibrium 2-6 weeks compared with the controls. We found that cerebellar lesions produced deficits (folia VI) in motor and cognitive aspects of a spatial task. The results indicate that transplantation of MSCs can significantly reduce the behavioral abnormalities of these animals during six weeks after engraftment. According to results of this assay, cell therapy by means of bone marrow derived adult stem cells promises for treatment of cerebellar diseases.