Humoral activity of cord blood-derived stem/progenitor cells: implications for stem cell-based adjuvant therapy of neurodegenerative disorders

Mechanism and Therapeutic Prospect of miRNAs in Neurodegenerative Diseases

MicroRNAs (miRNAs) are the smallest class of noncoding RNAs, which widely exist in animals and plants. They can inhibit translation or overexpression by combining with mRNA and participate in posttranscriptional regulation of genes, resulting in reduced expression of target proteins, affecting the development, growth, aging, metabolism, and other physiological and pathological processes of animals and plants. It is a powerful negative regulator of gene expression. It mediates the information exchange between different cellular pathways in cellular homeostasis and stress response and regulates the differentiation, plasticity, and neurotransmission of neurons. In neurodegenerative diseases, in addition to the complex interactions between genetic susceptibility and environmental factors, miRNAs can serve as a promising diagnostic tool for diseases. They can also increase or reduce neuronal damage by regulating the body's signaling pathways, immune system, stem cells, gut microbiota, etc. They can not only affect the occurrence of diseases and exacerbate disease progression but also promote neuronal repair and reduce apoptosis, to prevent and slow down the development of diseases. This article reviews the research progress of miRNAs on the mechanism and treatment of neurodegenerative diseases in the nervous system. This trial is registered with NCT01819545, NCT02129452, NCT04120493, NCT04840823, NCT02253732, NCT02045056, NCT03388242, NCT01992029, NCT04961450, NCT03088839, NCT04137926, NCT02283073, NCT04509271, NCT02859428, and NCT05243017.

Umbilical Cord Blood Cell Clearance Post-Infusion in Immune-Competent Children with Cerebral Palsy

Umbilical cord blood cells have therapeutic potential for neurological disorders, through a paracrine mechanism of action. A greater understanding of the safety and immunological effects of allogeneic donor cord blood cells in the context of a healthy recipient immune system, such as in cerebral palsy, is needed. This study aimed to determine how quickly donor cord blood cells were cleared from the circulation in children with cerebral palsy who received a single intravenous infusion of 12/12 human leucocyte antigen (HLA)-matched sibling cord blood cells. Twelve participants with cerebral palsy aged 2-12 years received cord blood cell infusions as part of a phase I trial of umbilical blood infusion for cerebral palsy. Digital droplet PCR analysis of DNA copy number variants specific to donor and recipient was used to assess donor DNA clearance at five timepoints post-infusion, a surrogate measure of cell clearance. Donor cells were cleared by 3 months post-infusion in 11/12 participants. When detected, donor DNA was at a fraction of 0.01-0.31% of total DNA with no signs of graft-versus-host disease in any participant. The donor DNA clearance times provided by this study have important implications for understanding the safety of allogeneic cord blood cell infusion for cerebral palsy and translational tissue engineering or regenerative medicine research in other disorders.

Ablation of cardiomyocyte-derived BDNF during development causes myocardial degeneration and heart failure in the adult mouse heart

Objective

Brain-derived neurotrophic factor (BDNF) and its receptor TrkB-T1 were recently found to be expressed in cardiomyocytes. However, the functional role of cardiomyocyte-derived BDNF in heart pathophysiology is not yet fully known. Recent studies revealed that BDNF-TrkB pathway plays a critical role to maintain integrity of cardiac structure and function, cardiac pathology and regeneration of myocardial infarction (MI). Therefore, the BDNF-TrkB pathway may be a novel target for myocardial pathophysiology in the adult heart.

Approach and results

In the present study, we established a cardiomyocyte-derived BDNF conditional knockout mouse in which BDNF expression in developing cardiomyocytes is ablated under the control of the Myosin heavy chain 6 (MYH6) promoter. The results of the present study show that ablation of cardiomyocyte-derived BDNF during development does not impair survival, growth or reproduction; however, in the young adult heart, it causes cardiomyocyte death, degeneration of the myocardium, cardiomyocyte hypertrophy, left atrial appendage thrombosis, decreased cardiac function, increased cardiac inflammation and ROS activity, and metabolic disorders, leading to heart failure (HF) in the adult heart and eventually resulting in a decrease in the one-year survival rate. In addition, ablation of cardiomyocyte-derived BDNF during the developmental stage leads to exacerbation of cardiac dysfunction and poor regeneration after MI in adult hearts.

Conclusion

Cardiomyocyte-derived BDNF is irreplaceable for maintaining the integrity of cardiac structure and function in the adult heart and regeneration after MI. Therefore, the BDNF-TrkB pathway will be a novel target for myocardial pathophysiology in the adult heart.

Effect of expansion of human umbilical cord blood CD34 + cells on neurotrophic and angiogenic factor expression and function

The use of CD34 + cell-based therapies has largely been focused on haematological conditions. However, there is increasing evidence that umbilical cord blood (UCB) CD34 + -derived cells have neuroregenerative properties. Due to low cell numbers of CD34 + cells present in UCB, expansion is required to produce sufficient cells for therapeutic purposes, especially in adults or when frequent applications are required. However, it is not known whether expansion of CD34 + cells has an impact on their function and neuroregenerative capacity. We addressed this knowledge gap in this study, via expansion of UCB-derived CD34 + cells using combinations of LDL, UM171 and SR-1 to yield large numbers of cells and then tested their functionality. CD34 + cells expanded for 14 days in media containing UM171 and SR-1 resulted in over 1000-fold expansion. The expanded cells showed an up-regulation of the neurotrophic factor genes BDNF, GDNF, NTF-3 and NTF-4, as well as the angiogenic factors VEGF and ANG. In vitro functionality testing showed that these expanded cells promoted angiogenesis and, in brain glial cells, promoted cell proliferation and reduced production of reactive oxygen species (ROS) during oxidative stress. Collectively, this study showed that our 14-day expansion protocol provided a robust expansion that could produce enough cells for therapeutic purposes. These expanded cells, when tested in in vitro, maintained functionality as demonstrated through promotion of cell proliferation, attenuation of ROS production caused by oxidative stress and promotion of angiogenesis.

Adjuvant Lineage-Negative Cell Therapy as a Potential Silencer of the Complement-Mediated Immune System in ALS Patients

ALS remains a fatal, neurodegenerative motor neuron disease. Numerous studies seem to confirm that innate immune system is involved in the pathophysiology of ALS. Hence, the assessment of the complement system and attempts to modify its activity remain the target of medical intervention in ALS. In the present study, three intrathecal administrations of autologous bone marrow-derived lineage-negative (Lin^–) cells were performed every 6 weeks in 20 sporadic ALS patients. The concentrations of various complement components in the cerebrospinal fluid and plasma at different time points after cell injection were quantified using a Luminex multiplex. The results of the complement system were correlated with the level of leukocytes, neutrophils, lymphocytes, fibrinogen and CRP in the peripheral blood and the functional status of ALS patients using Norris and ALS-FRSr scales. The study showed a statistically significant decrease in plasma C3b concentration in all 7th days after cell application. In parallel, a peak decrease in neutrophil count and CRP level was observed on days 5–7, with a simultaneous maximum clinical improvement on days 7–28 of each Lin^– cell administration. Adjuvant Lin^– cell therapy appears to have the silencing potential on the complement-mediated immune system and thus suppress pro-inflammatory reactions responsible for neurodegeneration. However, further in-depth studies are necessary to address this issue.

Long-Term Effects of Adjuvant Intravitreal Treatment with Autologous Bone Marrow-Derived Lineage-Negative Cells in Retinitis Pigmentosa

BACKGROUND

Autologous bone marrow-derived lineage-negative (Lin-) cells present antiapoptotic and neuroprotective activity. The aim of the study was to evaluate the safety and efficacy of novel autologous Lin- cell therapy during a 12-month follow-up period.

METHODS

Intravitreal injection of Lin- cells in 30 eyes with retinitis pigmentosa (RP) was performed. The fellow eyes (FEs) were considered control eyes. Functional and morphological eye examinations were performed before and 1, 3, 6, 9, and 12 months after the injection.

RESULTS

Patients whose symptoms started less than 10 years ago gained 14 ± 10 letters, while those with a longer disease duration gained 2.86 ± 8.54 letters compared to baseline at the 12-month follow-up (p = 0.021). There were significantly higher differences in response densities of P1-wave amplitudes in the first ring of multifocal ERGs in treated eyes than FE recordings in all follow-up points were detected. Accordingly, the mean deviation in 10-2 static perimetry improved significantly in the treated eyes compared with fellow eyes 12 months after the procedure. The QoL scores improved significantly and lasted until the 9-month visit.

CONCLUSION

Lin- cell-based therapy is safe and effective, especially for a well-selected group of RP patients who still maintained good function of the foveal cones.

Humoral Influence of Repeated Lineage-Negative Stem/Progenitor Cell Administration on Articulatory Functions in ALS Patients

Amyotrophic lateral sclerosis (ALS) remains a fatal, neurodegenerative disease frequently leading to dysarthria and impaired swallowing. Better understanding of ALS pathophysiology is prompting the use of humoral cell therapies. Hence, a repeated cellular therapy was applied to ALS patients as an attempt to prevent speech deterioration. Autologous bone marrow-derived lineage-negative (Lin⁻) cells were intrathecally administered three times at six-week intervals to 42 sporadic ALS patients. Patients were examined for articulatory functions using subjective (VHI) and objective (FDA) scales. Selected trophic, proinflammatory factors and expression profiles of miRNA were measured in cerebrospinal fluid (CSF) and plasma by multiplex Luminex and q-PCR in different timepoints. Of the 42 patients who received the Lin⁻ cells, 6 showed improvement in articulatory functions, 27 remained stable, and 9 deteriorated after 18 weeks of therapy according to FDA scale. Clinical improvement was particularly evident by the 7^th day of each cell application and concerned better cough and swallow reflex, soft palate, laryngeal time, pitch, and volume. These results correlated with significant changes in the concentration of various trophic and proinflammatory factors and miRNA expression profiles. A multiple application of Lin⁻ cells proved to be safe and feasible. The repeated procedure can potentate a humoral effect and prevent speech deterioration. A short-lasting trophic effect of each Lin⁻ cells administration was observed on local and systemic level. However, further in-depth studies are necessary to sustain the beneficial effect.

Repeated Application of Autologous Bone Marrow-Derived Lineage-Negative Stem/Progenitor Cells-Focus on Immunological Pathways in Patients with ALS

Therapeutic interventions in amyotrophic lateral sclerosis (ALS) are still far from satisfying. Immune modulating procedures raise hopes for slowing the disease progression. Stem cell therapies are believed to possess the ability to regulate innate and adaptive immune response and inflammation processes. Hence, three intrathecal administrations of autologous bone marrow-derived lineage-negative (Lin^–) cells were performed every six weeks in 40 sporadic ALS patients. The concentrations of inflammatory-related proteins and expression profiles of selected miRNA in the cerebrospinal fluid (CSF) and plasma at different timepoints post-transplantation were quantified by multiplex Luminex and qRT-PCR. The global gene expression in nucleated blood cells was assessed using the gene microarray technique. According to the ALS Functional Rating Scale (FRSr), the study population was divided into responders (group I, n = 17) and non-responders (group II, n = 23). A thorough analysis of the pro-inflammatory expression profiles, regulated miRNA pathways, and global gene expression profiles at the RNA level revealed the local and systemic effects of Lin^– cell therapy on the immune system of patients with ALS. The autologous application of Lin^– cells in CSF modulates immune processes and might prevent the progression of neurodegeneration. However, further in-depth studies are necessary to confirm the findings, and prolonged intervention is needed to maintain therapeutic effects.

The effectiveness of various cytotherapeutic strategies for the treatment of ischemic stroke: a Bayesian network meta-analysis of randomized controlled trials

BACKGROUND

Cytotherapy is a potential treatment for ischemic stroke (IS) patients but lacks uniform procedures. We aimed to assess the impact of the time of intervention, cell type, dose, and route of administration on the clinical effects by network meta-analysis.

METHODS

We searched public electronic databases through July 7, 2019. Bayesian network meta-analyses were performed to compare differences among different cytotherapeutic strategies.

RESULTS

Cytotherapy can significantly improve patients' activity of daily living according to the modified Rankin Scale (standard mean difference (SMD) - 0.81; 95% confidence interval (CI) - 1.58, - 0.03; p = 0.0417) and Barthel Index (SMD 0.67; 95% CI 0.05, 1.30; p = 0.036) results as well as improve neurological recovery (SMD - 0.93; 95% CI - 1.29, - 0.57; p < 0.001). Network meta-analysis showed that the intra-arterial injection of large amounts of mononuclear cells (NCs) or aldehyde dehydrogenase (ALDH)-positive cells was beneficial for improving patients' activity of daily living, while CD34+ cells through intracerebral injection had an advantage in the recovery of injured nerve function. Intravenous injection of mesenchymal stem cells (MSCs) or endothelial progenitor cells (EPCs) was beneficial in reducing mortality and serious adverse event (SAE) onset.

CONCLUSIONS

In the subacute stage, the intra-arterial injection of NCs or ALDH cells improves patients' activity of daily living. Additionally, CD34+ cells through intracerebral injection had an advantage in the recovery of injured nerve function even in the chronic stage. Intravenous injection of MSCs or EPCs is a safety delivery route that can reduce mortality and SAE onset. However, further clinical studies are still needed to confirm these results.

Single group multisite safety trial of sibling cord blood cell infusion to children with cerebral palsy: study protocol and rationale

INTRODUCTION

Cerebral palsy (CP) is the most common physical disability of childhood but has no cure. Stem cells have the potential to improve brain injury and are proposed as a therapy for CP. However, many questions remain unanswered about the most appropriate cell type, timing of infusions, dose required and associated risks. Therefore, human safety and efficacy trials are necessary to progress knowledge in the field.

METHODS AND ANALYSIS

This is a single group study with sample size n=12 to investigate safety of single-dose intravenous 12/12 human leucocyte antigen-matched sibling cord blood cell infusion to children with CP aged 1-16 years without immune suppression. The study is similar to a 3+3 design, where the first two groups of participants have severe CP, and the final six participants include children with all motor severities. Children will be monitored for adverse events and the duration that donor cells are detected. Assessments at baseline, 3 and 12 months will investigate safety and preliminary evidence of change in gross motor, fine motor, cognitive and quality of life outcomes.

ETHICS AND DISSEMINATION

Full approval was obtained from The Royal Children's Hospital Human Research Ethics Committee, and a clinical trial notification was accepted by Australia's Therapeutic Goods Administration. Participant guardian informed consent will be obtained before any study procedures. The main results of this study will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ACTRN12616000403437, NCT03087110.

Local and Systemic Humoral Response to Autologous Lineage-Negative Cells Intrathecal Administration in ALS Patients

Amyotrophic lateral sclerosis (ALS) remains a fatal disease with limited therapeutic options. Signaling via neurotrophins (NTs), neuroinflammation, and certain micro-RNAs are believed to play essential role in ALS pathogenesis. Lineage-negative stem/progenitor cells (Lin⁻) were obtained from bone marrow of 18 ALS patients and administered intrathecally. Clinical assessment was performed using ALS Functional Rating Scale (FRSr) and Norris scale. Protein concentrations were measured in plasma and cerebrospinal fluid (CSF) by multiplex fluorescent bead-based immunoassay. Gene expression in nucleated blood cells was assessed using gene microarray technique. Finally, miRNA expression was analyzed using qPCR in CSF and plasma samples. We observed a significant decrease of C-reactive protein (CRP) concentration in plasma on the seventh day from the application of cells. Gene array results revealed decreased expression of gene sets responsible for neutrophil activation. Further analysis revealed moderate negative correlation between CRP level in CSF and clinical outcome. Brain-derived neurotrophic factor (BDNF) concentrations in both plasma and CSF significantly correlated with the favorable clinical outcome. On a micro-RNA level, we observed significant increase of miR-16-5p expression one week after transplantation in both body fluids and significant increase of miR-206 expression in plasma. Administration of Lin⁻ cells may decrease inflammatory response and prevent neurodegeneration. However, these issues require further investigations.

The Effect of Intracoronary Infusion of Autologous Bone Marrow-Derived Lineage-Negative Stem/Progenitor Cells on Remodeling of Post-Infarcted Heart in Patient with Acute Myocardial Infarction

Introduction: Regenerative capacity of the heart is limited, and the post-infarct left ventricle (LV) dysfunction is associated with poor prognosis. Administration of stem/progenitor cells (SPCs) is a promising approach for cardiac regeneration. Objectives: In the study, we assessed LV function and post-infarcted remodeling in patients with ST-elevated myocardial infarct (STEMI) who received autologous lineage-negative (LIN^-) SPCs. Patients and methods: Patients with STEMI and one-vessel coronary artery disease treated with percutaneous revascularisation were divided into study group (LIN^- group, 15 patients) that received standard therapy and autologous BM-derived LIN^- SPCs and control group (standard therapy group, 19 patients). The cells were administered intracoronary 24 hours after STEMI. The follow-up was 12 months with subsequent non-invasive tests and laboratory parameter evaluation on days 1^st, 3^rd, and 7^th as well as at 1^st, 3^rd, 6^th and 12^th month after STEMI. Results: All procedures related to SPCs administration were well tolerated by the patients. In 12-month follow-up, there were no major adverse cardiac events connected with LIN^- SPCs administration. During 12-month follow-up, 9 patients from LIN^- group (Responders) achieved an improvement in LV ejection fraction (>10% after 12 months) with no signs of unfavorable LV remodeling. Laboratory parameters analysis showed that Troponin T levels were significantly lower until day 7^th in the Responders group, while brain natriuretic peptide (BNP) level remained significantly lower from day 3^rd to 12^th month respectively. Conclusions: Intracoronary infusion of autologous BM-derived LIN^- stem/progenitor cells is feasible and safe for patient. Improvement in LV function and prevention of unfavorable remodeling in the 60% of study group seems relatively promising. Stem cell-based therapy for cardiac regeneration still needs more accurate and extensive investigations to estimate and improve their efficacy.

Articulation recovery in ALS patients after lineage-negative adjuvant cell therapy - preliminary report

Background: Amyotrophic lateral sclerosis (ALS) is one of the most frequently occurring neurodegenerative diseases affecting speech and swallowing. This preliminary study aimed to investigate whether an autologous lineage-negative stem/progenitor cell therapy applied to ALS patients affects the level of selected trophic and proinflammatory factors, and subsequently improves the articulation. Methods: We enrolled 12 patients with sporadic ALS, who underwent autologous bone marrow-derived lineage negative (LIN^-) cells administration into cerebrospinal fluid (CSF). We evaluated patients' articulation using the Frenchay Dysarthria Assessment on days 0 and 28 following the LIN^- cells administration. Concentrations of various factors (BDNF, NGF, ANGP-2, VEGF, PDGF-AA, PEDF, COMP-FH, CRP, C3, C4) in CSF were quantified by multiplex fluorescent bead-based immunoassays in the samples collected on the day of LIN^- cells administration and 28 days later. On top of this, we assessed levels of BDNF and NGF in the patients' plasma on the day of the injection, three, seven days and three months after the treatment. Results: Of the 12 patients who received the LIN^- cell therapy 8 showed short-termed improvement in articulatory functions (group I), which was particularly noticeable in better phonation time, lips and soft palate performance, swallowing reflex and voice loudness. Four patients (group II) did not show substantial improvement. CSF concentrations of BDNF, ANGP-2 and PDGF-AA in group I decreased significantly 28 days after LIN^- cells administration. The highest concentration levels of BDNF in group II and NGF in both groups in blood plasma were observed on day 3 following the injection. Conclusions: The outcomes of the LIN^- cell application in ALS treatment of articulatory organs are promising. The procedure proved to be safe and feasible. A short-lasting trophic effect of autologous LIN^- administration could encourage repeated cell's application in order to sustain their beneficial effects, however this approach needs further investigation.

Induction of regional chemokine expression in response to human umbilical cord blood cell infusion in the neonatal mouse ischemia-reperfusion brain injury model

Regenerative medicine using umbilical cord blood (UCB) cells shows promise for the treatment of cerebral palsy. Although the efficacy of this therapy has been seen in the clinic, the mechanisms by which UCB cells interact and aid in the improvement of symptoms are not clear. We explored the chemokine expression profile in damaged brain tissue in the neonatal mouse ischemia-reperfusion (IR) brain injury model that was infused with human UCB (hUCB) cells. IR brain injury was induced in 9-day-old NOD/SCID mice. hUCB cells were administered 3 weeks post brain injury. Chemokine expression profiles in the brain extract were determined at various time points. Inflammatory chemokines such as CCL1, CCL17, and CXCL12 were transiently upregulated by 24 hours post brain injury. Upregulation of other chemokines, including CCL5, CCL9, and CXCL1 were prolonged up to 3 weeks post brain injury, but most chemokines dissipated over time. There were marked increases in levels of CCL2, CCL12, CCL20, and CX3CL1 in response to hUCB cell treatment, which might be related to the new recruitment and differentiation of neural stem cells, leading to the induction of tissue regeneration. We propose that the chemokine expression profile in the brain shifted from responding to tissue damage to inducing tissue regeneration. hUCB cell administration further enhanced the production of chemokines, and chemokine networks may play an active role in tissue regeneration in neonatal hypoxic-ischemic brain injury.

Novel Evidence of the Increase in Angiogenic Factor Plasma Levels after Lineage-Negative Stem/Progenitor Cell Intracoronary Infusion in Patients with Acute Myocardial Infarction

Cell therapy raises hope to reduce the harmful effects of acute myocardial ischemia. Stem and progenitor cells (SPCs) may be a valuable source of trophic factors. In this study, we assessed the plasma levels of selected trophic factors in patients undergoing application of autologous bone marrow (BM)-derived, lineage-negative (Lin^-) stem/progenitor cells into the coronary artery in the acute phase of myocardial infarction. The study group consisted of 15 patients with acute myocardial infarction (AMI) who underwent percutaneous revascularization and, afterwards, Lin^- stem/progenitor cell administration into the infarct-related artery. The control group consisted of 19 patients. BM Lin^- cells were isolated using immunomagnetic methods. Peripheral blood was collected on day 0, 2, 4, and 7 and after the first and third month to assess the concentration of selected trophic factors using multiplex fluorescent bead-based immunoassays. We found in the Lin^- group that several angiogenic trophic factors (vascular endothelial growth factor, Angiopoietin-1, basic fibroblast growth factor, platelet-derived growth factor-aa) plasma level significantly increased to the 4th day after myocardial infarction. In parallel, we noticed a tendency where the plasma levels of the brain-derived neurotrophic factor were increased in the Lin^- group. The obtained results suggest that the administered SPCs may be a valuable source of angiogenic trophic factors for damaged myocardium, although this observation requires further in-depth studies.

Influence of Lineage-Negative Stem Cell Therapy on Articulatory Functions in ALS Patients

Introduction

Amyotrophic lateral sclerosis (ALS) is a fatal, neurodegenerative disease, leading to loss of muscle strength and motor control. Impaired speech and swallowing lower the quality of life and consequently may induce acute respiratory failure. Bone marrow-derived stem and progenitor cells (SPCs) may be a valuable source of trophic factors. In this study, we assessed whether adjuvant cellular therapy could affect the levels of selected neurotrophins and proinflammatory factors in the cerebrospinal fluid (CSF) and subsequently prevent the deterioration of articulation.

Materials and Methods

The study group consisted of 32 patients with sporadic ALS who underwent autologous lineage-negative (Lin⁻) stem cell intrathecal administration to the spinal canal. Lin⁻ cells were aspirated from the bone marrow and isolated using immunomagnetic beads and a lineage cell depletion kit. Patients were examined for articulatory functions by means of the Voice Handicap Index (VHI) questionnaire and Frenchay Dysarthria Assessment (FDA). In parallel, we carried out the analysis of selected trophic and proinflammatory factors in CSF utilizing multiplex fluorescent bead-based immunoassays.

Results

Of the 32 patients who received the Lin⁻ progenitor cell therapy, 6 (group I) showed improvement in articulatory functions, 23 remained stable (group II), and 3 deteriorated (group III) on the 28^th day. The improvement was particularly noticeable in a better cough reflex, laryngeal time, and dribble reflex. A statistically significant lower level of brain-derived neurotrophic factor (BDNF) was observed on day 0 in group I compared to group II. The CSF concentrations of C-reactive protein (CRP) in group I significantly decreased 7 days after Lin⁻ SPC transplantation. On the contrary, a significant increase in the tumor necrosis factor receptor (TNF-R) level was confirmed among patients from group I with improvement of dribble and coughing reflex, tongue movements, and respiration on the 7^th day, as well as on day 28 including dribble reflex solely.

Conclusions

An application of Lin⁻ stem cells could potentate the beneficial humoral effect. The prevention of deterioration of articulatory functions in ALS patients after applying adjuvant Lin⁻ stem cell therapy seems to be promising. Although the procedure is safe and feasible, it requires further in-depth studies.

Preclinical Evaluation of Long-Term Neuroprotective Effects of BDNF-Engineered Mesenchymal Stromal Cells as Intravitreal Therapy for Chronic Retinal Degeneration in Rd6 Mutant Mice

This study aimed to investigate whether the transplantation of genetically engineered bone marrow-derived mesenchymal stromal cells (MSCs) to overexpress brain-derived neurotrophic factor (BDNF) could rescue the chronic degenerative process of slow retinal degeneration in the rd6 (retinal degeneration 6) mouse model and sought to identify the potential underlying mechanisms. Rd6 mice were subjected to the intravitreal injection of lentivirally modified MSC-BDNF or unmodified MSC or saline. In vivo morphology, electrophysiological retinal function (ERG), and the expression of apoptosis-related genes, as well as BDNF and its receptor (TrkB), were assessed in retinas collected at 28 days and three months after transplantation. We observed that cells survived for at least three months after transplantation. MSC-BDNF preferentially integrated into the outer retinal layers and considerably rescued damaged retinal cells, as evaluated by ERG and immunofluorescence staining. Additionally, compared with controls, the therapy with MSC-BDNF was associated with the induction of molecular changes related to anti-apoptotic signaling. In conclusion, BDNF overexpression observed in retinas after MSC-BDNF treatment could enhance the neuroprotective properties of transplanted autologous MSCs alone in the chronically degenerated retina. This research provides evidence for the long-term efficacy of genetically-modified MSC and may represent a strategy for treating various forms of degenerative retinopathies in the future.

Safety and Feasibility of Lin- Cells Administration to ALS Patients: A Novel View on Humoral Factors and miRNA Profiles

Therapeutic options for amyotrophic lateral sclerosis (ALS) are still limited. Great hopes, however, are placed in growth factors that show neuroprotective abilities (e.g., nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and vascular endothelial growth factor (VEGF)) and in the immune modulating features, in particular, the anti-inflammatory effects. In our study we aimed to investigate whether a bone marrow-derived lineage-negative (Lin-) cells population, after autologous application into cerebrospinal fluid (CSF), is able to produce noticeable concentrations of trophic factors and inflammatory-related proteins and thus influence the clinical course of ALS. To our knowledge, the evaluation of Lin- cells transplantation for ALS treatment has not been previously reported. Early hematopoietic Lin- cells were isolated from twelve ALS patients’ bone marrow, and later, the suspension of cells was administered into the subarachnoid space by lumbar puncture. Concentrations of selected proteins in the CSF and plasma were quantified by multiplex fluorescent bead-based immunoassays at different timepoints post-transplantation. We also chose microRNAs (miRNAs) related to muscle biology (miRNA-1, miRNA-133a, and miRNA-206) and angiogenesis and inflammation (miRNA-155 and miRNA-378) and tested, for the first time, their expression profiles in the CSF and plasma of ALS patients after Lin- cells transplantation. The injection of bone marrow cells resulted in decreased concentration of selected inflammatory proteins (C3) after Lin- cells injection, particularly in patients who had a better clinical outcome. Moreover, several analyzed miRNAs have changed expression levels in the CSF and plasma of ALS patients subsequent to Lin- cells administration. Interestingly, the expression of miR-206 increased in ALS patients, while miR-378 decreased both in the CSF and plasma one month after the cells’ injection. We propose that autologous lineage-negative early hematopoietic cells injected intrathecally may be a safe and feasible source of material for transplantations to the central nervous system (CNS) environment aimed at anti-inflammatory support provision for ALS adjuvant treatment strategies. Further research is needed to evaluate whether the observed effects could significantly influence the ALS progression.

BDNF - A key player in cardiovascular system

Neurotrophins (NTs) were first identified as target-derived survival factors for neurons of the central and peripheral nervous system (PNS). They are known to control neural cell fate, development and function. Independently of their neuronal properties, NTs exert unique cardiovascular activity. The heart is innervated by sensory, sympathetic and parasympathetic neurons, which require NTs during early development and in the establishment of mature properties, contributing to the maintenance of cardiovascular homeostasis. The identification of molecular mechanisms regulated by NTs and involved in the crosstalk between cardiac sympathetic nerves, cardiomyocytes, cardiac fibroblasts, and vascular cells, has a fundamental importance in both normal heart function and disease. The article aims to review the recent data on the effects of Brain-Derived Neurotrophic Factor (BDNF) on various cardiovascular neuronal and non-neuronal functions such as the modulation of synaptic properties of autonomic neurons, axonal outgrowth and sprouting, formation of the vascular and neural networks, smooth muscle migration, and control of endothelial cell survival and cardiomyocytes. Understanding these mechanisms may be crucial for developing novel therapeutic strategies, including stem cell-based therapies.

The effect of hypoxia preconditioning on the neural and stemness genes expression profiling in human umbilical cord blood mesenchymal stem cells

In recent years, human umbilical cord blood-derived mesenchymal stem cell (hUB-MSCs) has been regarded as an alternative source for stem cell therapy. In this study, we evaluated the effect of hypoxia preconditioning (HPC) on the expression of Nt-3, GFAP, Nestin, Oct-4 and Nanog genes and proliferative capacity of hUB-MSCs in comparison with normoxic conditions. HPC+Hypoxia protocol includes cultured hUB-MSCs for 15min at 2.5% O₂ and after that reoxygenation for 30min at 21% O₂ (HPC), and then hypoxia preconditioned hUB-MSCs subjected to 2.5% O₂ for 72h (Hypoxia). Conclusively, the results showed that hypoxic preconditioning is an effective strategy for enhancing proliferation capacity of hUB-MSCs, and also can trigger expression of some of the neural genes. In addition, the concept of involvement of oxygen tension in the expression of some of the neural genes of hUB-MSCs would be a good sign of enhanced neural differentiation potential in vitro.

Stem cells for ALS: An overview of possible therapeutic approaches

Amyotrophic lateral sclerosis (ALS) is an unusual, fatal, neurodegenerative disorder leading to the loss of motor neurons. After diagnosis, the average lifespan ranges from 3 to 5 years, and death usually results from respiratory failure. Although the pathogenesis of ALS remains unclear, multiple factors are thought to contribute to the progression of ALS, such as network interactions between genes, environmental exposure, impaired molecular pathways and many others. The neuroprotective properties of neural stem cells (NSCs) and the paracrine signaling of mesenchymal stem cells (MSCs) have been examined in multiple pre-clinical trials of ALS with promising results. The data from these initial trials indicate a reduction in the rate of disease progression. The mechanism through which stem cells achieve this reduction is of major interest. Here, we review the to-date pre-clinical and clinical therapeutic approaches employing stem cells, and discuss the most promising ones.

Evidence for proangiogenic cellular and humoral systemic response in patients with acute onset of spinal cord injury

CONTEXT/OBJECTIVE

Traumatic spinal cord injury (SCI) leads to disruption of local vasculature inducing secondary damage of neural tissue. Circulating endothelial progenitor cells (EPCs) play an important role in post-injury regeneration of vasculature, whereas endothelial cells (ECs) reflect endothelial damage.

METHODS

Twenty patients with SCI were assessed during the first 24 hours, at day 3, and day 7 post-injury and compared to 25 healthy subjects. We herein investigated EPC and EC counts by flow cytometry as well as the levels of soluble factors (SDF-1, HGF, VEGF, Ang2, EGF, endoglin, PLGF, FGF-2, ET-1, BDNF, IGF-1) regulating their migration and proangiogenic function. To better characterize peripheral blood (PB) cells, global gene expression profiles of PB-derived cells were determined using genome-wide RNA microarray technology.

RESULTS

We found significantly higher EPC (CD34(+)/CD133(+)/VEGFR2(+)) as well as EC (VEGFR2(+)) count in PB of patients with SCI within 7 days post-injury and the increased HGF, ET-1, Ang2, EGF, and PLGF plasma levels. Global gene expression analysis revealed considerably lower expression of genes associated with both innate and adaptive immune response in PB cells in patients.

CONCLUSION

Collectively, our findings demonstrate that SCI triggers bone marrow-derived EPC mobilization accompanied by increased circulating EC numbers. Significant changes in both chemoattractive and proangiogenic cytokines plasma levels occurring rapidly after SCI suggest their role in SCI-related regenerative responses to injury. Broadened knowledge concerning the mechanisms governing of human organism response to the SCI might be helpful in developing effective therapeutic strategies.

Neuroprotective and antiapoptotic activity of lineage-negative bone marrow cells after intravitreal injection in a mouse model of acute retinal injury

We investigated effects of bone marrow-derived, lineage-negative cell (Lin(-)BMC) transplantation in acute retinal injury. Lin(-)BMCs were intravitreally injected into murine eyes at 24 h after NaIO3-induced injury. Morphology, function, and expression of apoptosis-related genes, including brain-derived neurotrophic factor (BDNF) and its receptor, were assessed in retinas at 7 days, 28 days, and 3 months after transplantation. Moreover, global gene expression at day 7 was analyzed by RNA arrays. We observed that Lin(-)BMCs integrated into outer retinal layers improving morphological retinal structure and induced molecular changes such as downregulation of proapoptotic caspase-3 gene, a decrease in BAX/BCL-2 gene ratio, and significant elevation of BDNF expression. Furthermore, transplanted Lin(-)BMCs differentiated locally into cells with a macrophage-like phenotype. Finally, Lin(-)BMCs treatment was associated with generation of two distinct transcriptomic patterns. The first relates to downregulated genes associated with regulation of neuron cell death and apoptosis, response to oxidative stress/hypoxia and external stimuli, and negative regulation of cell proliferation. The second relates to upregulated genes associated with neurological system processes and sensory perception. Collectively, our data demonstrate that transplanted Lin(-)BMCs exert neuroprotective function against acute retinal injury and this effect may be associated with their antiapoptotic properties and ability to express neurotrophic factors.

Tissue regeneration in stroke: cellular and trophic mechanisms

Stroke is a leading cause of morbidity in the developed world and results in chronic disability in many cases. The literature related to the critical factors that regulate tissue self-regeneration in stroke is still limited, which restricts effective therapy. However, optimism in this area has been provided by recent research. The mechanisms involved in tissue regeneration and the mode of the participation of stem/progenitor cells and soluble protein neurotrophic factors in this process may yield a more complete understanding of the nature of stroke. This review summarizes the current understanding of both cellular and humoral issues with a particular emphasis on how these issues contribute to tissue regeneration in stroke.