A comparison of neurosphere differentiation potential of canine bone marrow-derived mesenchymal stem cells and adipose-derived mesenchymal stem cells

Mesenchymal Stem Cells in Soft Tissue Regenerative Medicine: A Comprehensive Review

Soft tissue regeneration holds significant promise for addressing various clinical challenges, ranging from craniofacial and oral tissue defects to blood vessels, muscle, and fibrous tissue regeneration. Mesenchymal stem cells (MSCs) have emerged as a promising tool in regenerative medicine due to their unique characteristics and potential to differentiate into multiple cell lineages. This comprehensive review explores the role of MSCs in different aspects of soft tissue regeneration, including their application in craniofacial and oral soft tissue regeneration, nerve regeneration, blood vessel regeneration, muscle regeneration, and fibrous tissue regeneration. By examining the latest research findings and clinical advancements, this article aims to provide insights into the current state of MSC-based therapies in soft tissue regenerative medicine.

Mesenchymal stem cells for regenerative medicine in central nervous system

Mesenchymal stem cells (MSCs) are multipotent stem cells, whose paracrine and immunomodulatory potential has made them a promising candidate for central nervous system (CNS) regeneration. Numerous studies have demonstrated that MSCs can promote immunomodulation, anti-apoptosis, and axon re-extension, which restore functional neural circuits. The therapeutic effects of MSCs have consequently been evaluated for application in various CNS diseases including spinal cord injury, cerebral ischemia, and neurodegenerative disease. In this review, we will focus on the research works published in the field of mechanisms and therapeutic effects of MSCs in CNS regeneration.

Can a Scaffold Enriched with Mesenchymal Stem Cells Be a Good Treatment for Spinal Cord Injury?

Spinal cord injury (SCI) is a worldwide highly crippling disease that can lead to the loss of motor and sensory neurons. Among the most promising therapies, there are new techniques of tissue engineering based on stem cells that promote neuronal regeneration. Among the different types of stem cells, mesenchymal stem cells (MSCs) seem the most promising. Indeed, MSCs are able to release trophic factors and to differentiate into the cell types that can be found in the spinal cord. Currently, the most common procedure to insert cells in the lesion site is infusion. However, this causes a low rate of survival and engraftment in the lesion site. For these reasons, tissue engineering is focusing on bioresorbable scaffolds to help the cells to stay in situ. Scaffolds do not only have a passive role but become fundamental for the trophic support of cells and the promotion of neuroregeneration. More and more types of materials are being studied as scaffolds to decrease inflammation and increase the engraftment as well as the survival of the cells. Our review aims to highlight how the use of scaffolds made from biomaterials enriched with MSCs gives positive results in in vivo SCI models as well as the first evidence obtained in clinical trials.

Thin films of functionalized carbon nanotubes support long-term maintenance and cardio-neuronal differentiation of canine induced pluripotent stem cells

Induced pluripotent stem cells (iPSCs) are a promising cell source for regenerative medicine. However, their feeder-free maintenance in undifferentiated states remains challenging. In recent past extensive studies have been directed using pristine or functionalized carbon nanotube in tissue engineering. Here we proposed thin films of functionalized carbon nanotubes (OH-single-walled CNTs [SWCNTs] and OH-multiwalled CNTs [MWCNTs]), as alternatives for the feeder-free in vitro culture of canine iPSCs (ciPSCs), considered as the cellular model. The ciPSC colonies could maintain their dome-shaped compactness and other characteristics when propagated on CNT films. Concomitantly, high cell viability and upregulation of pluripotency-associated genes and cell adhesion molecules were observed, further supported by molecular docking. Moreover, CNTs did not have profound toxic effects compared to feeder cultures as evident by cytocompatibility studies. Further, cardiac and neuronal differentiation of ciPSCs was induced on these films to determine their influence on the differentiation process. The cells retained differentiation potential and the nanotopographical features of the substrates provided positive cues to enhance differentiation to both lineages as evident by immunocytochemical staining and marker gene expression. Overall, OH-SWCNT provided better cues, maintained pluripotency, and induced the differentiation of ciPSCs. These results indicate that OH-functionalized CNT films could be used as alternatives for the feeder-free maintenance of ciPSCs towards prospective utilization in regenerative medicine.

Transdifferentiation of canine mesenchymal stem cells into neuron-like cells by induction with β-mercaptoethanol

The objective of this study was to check whether β- mercaptoethanol in a culture medium can induce the neuronal differentiation of canine MSCs. The canine bonemarrow derived MSCs were first pre-inducted with 1 mM BME for 24 hrs followed by induction in a serum-free medium supplemented with 4 mM BME without FBS for another 6 days. Morphological changes in MSCs from spindle-shaped to neuron-like branching from the edges of the cells were noticed at the end of induction. These neuronlike cells were found positive for the immunophenotypic expression of different neural cell markers β-tubulin III, MAP-2 and Nestin. In RT-PCR analysis, it was also evident that the relative expressions of these representative genes were significantly higher in the differentiated cells. On the basis of our observations, it can be summarized that the BME induction of canine MSCs resulted in morphological changes that resembled neuron-like cells which were found to express the representative neuronal markers. Therefore, inducing canine MSCs with BME resulted in the generation of neuron-like cells that might be utilized for the prospective therapeutic applications in veterinary medicine.

Long Non-coding RNA Regulation of Mesenchymal Stem Cell Homeostasis and Differentiation: Advances, Challenges, and Perspectives

Given the self-renewal, multi-differentiation, immunoregulatory, and tissue maintenance properties, mesenchymal stem cells (MSCs) are promising candidates for stem cell-based therapies. Breakthroughs have been made in uncovering MSCs as key contributors to homeostasis and the regenerative repair of tissues and organs derived from three germ layers. MSC differentiation into specialized cell types is sophisticatedly regulated, and accumulating evidence suggests long non-coding RNAs (lncRNAs) as the master regulators of various biological processes including the maintenance of homeostasis and multi-differentiation functions through epigenetic, transcriptional, and post-translational mechanisms. LncRNAs are ubiquitous and generally referred to as non-coding transcripts longer than 200 bp. Most lncRNAs are evolutionary conserved and species-specific; however, the weak conservation of their sequences across species does not affect their diverse biological functions. Although numerous lncRNAs have been annotated and studied, they are nevertheless only the tip of the iceberg; the rest remain to be discovered. In this review, we characterize MSC functions in homeostasis and highlight recent advances on the functions and mechanisms of lncRNAs in regulating MSC homeostasis and differentiation. We also discuss the current challenges and perspectives for understanding the roles of lncRNAs in MSC functions in homeostasis, which could help develop promising targets for MSC-based therapies.

Adipose-Derived Mesenchymal Stromal Cells in Regenerative Medicine: State of Play, Current Clinical Trials, and Future Prospects

Significance: Wound healing is a complex process involving pain and inflammation, where innervation plays a central role. Managing wound healing and pain remains an important issue, especially in pathologies such as excessive scarring (often leading to fibrosis) or deficient healing, leading to chronic wounds. Recent Advances: Advances in therapies using mesenchymal stromal cells offer new insights for treating indications that previously lacked options. Adipose-derived mesenchymal stromal cells (AD-MSCs) are now being used to a much greater extent in clinical trials for regenerative medicine. However, to be really valid, these randomized trials must imperatively follow strict guidelines such as consolidated standards of reporting trials (CONSORT) statement. Indeed, AD-MSCs, because of their paracrine activities and multipotency, have potential to cure degenerative and/or inflammatory diseases. Combined with their relatively easy access (from adipose tissue) and proliferation capacity, AD-MSCs represent an excellent candidate for allogeneic treatments. Critical Issues: The success of AD-MSC therapy may depend on the robustness of the biological functions of AD-MSCs, which requires controlling source heterogeneity and production processes, and development of biomarkers that predict desired responses. Several studies have investigated the effect of AD-MSCs on innervation, wound repair, or pain management separately, but systematic evaluation of how those effects could be combined is lacking. Future Directions: Future studies that explore how AD-MSC therapy can be used to treat difficult-to-heal wounds, underlining the need to thoroughly characterize the cells used, and standardization of preparation processes are needed. Finally, how this a priori easy-to-use cell therapy treatment fits into clinical management of pain, improvement of tissue healing, and patient quality of life, all need to be explored.

Neural differentiation of canine mesenchymal stem cells/multipotent mesenchymal stromal cells

BACKGROUND

The ability of adipose tissue-derived multipotent mesenchymal stromal cells/mesenchymal stem cells (ASCs) to differentiate in neural lineages promises progress in the field of regenerative medicine, especially for replacing neuronal tissue damaged by different neurological disorders. Reprogramming of ASCs can be induced by the growth medium with neurogenic inductors and specific growth factors. We investigated the neural differentiation potential of canine ASCs using several growth media (KEM, NIMa, NIMb, NIMc) containing various combinations of neurogenic inductors: B27 supplement, valproic acid, forskolin, N2-supplement, and retinoic acid. Cells were first preconditioned in the pre-differentiation neural induction medium (mitogenically stimulated; STIM1), followed by the induction of neuronal differentiation.

RESULTS

After 3, 6, and 9 days of neural induction, elongated neural-like cells with bipolar elongations were observed, and some oval cells with light nuclei appeared. The expression of neuronal markers tubulin beta III (TUBB3), neurofilament H (NF-H), microtubule-associated protein-2 (MAP2), and glial fibrillary acidic protein (GFAP) was observed using immunocytochemistry, which confirmed the differentiation into neurons and glial cells. Flow cytometry analysis showed high GFAP expression (between 70 and 90% of all cells) after cells had been growing three days in the neural induction medium a (NIMa). Around 25% of all cells also expressed adult neuronal markers NF-H and MAP2. After nine days of ASCs differentiation, the expression of all neural markers was reduced. There were no differences between the neural differentiation of ASCs isolated from female or male dogs.

CONCLUSIONS

The differentiation repertoire of canine ASCs extends beyond mesodermal lineages. Using a defined neural induction medium, the canine ASCs differentiated into neural lineages and expressed markers of neuronal and glial cells, and also displayed the typical neuronal morphology. Differentiated ASCs can thus be a source of neural cellular lineages for the regenerative therapy of nerve damage and could be useful in the future for therapy or the modelling of neurodegenerative diseases.

Mesenchymal Stem Cells for Regenerative Medicine

In recent decades, the biomedical applications of mesenchymal stem cells (MSCs) have attracted increasing attention. MSCs are easily extracted from the bone marrow, fat, and synovium, and differentiate into various cell lineages according to the requirements of specific biomedical applications. As MSCs do not express significant histocompatibility complexes and immune stimulating molecules, they are not detected by immune surveillance and do not lead to graft rejection after transplantation. These properties make them competent biomedical candidates, especially in tissue engineering. We present a brief overview of MSC extraction methods and subsequent potential for differentiation, and a comprehensive overview of their preclinical and clinical applications in regenerative medicine, and discuss future challenges.

Pharmacological Notch pathway inhibition leads to cell cycle arrest and stimulates ascl1 and neurogenin2 genes expression in dental pulp stem cells-derived neurospheres

OBJECTIVE

Human dental pulp-derived stem cells (hDPSCs) are becoming an attractive source for cell-based neurorestorative therapies. As such, it is important to understand the molecular mechanisms that regulate the differentiation of hDPSCs toward the neuronal fate. Notch signaling plays key roles in neural stem/progenitor cells (NS/PCs) maintenance and prevention of their differentiation. The aim of this study was to address the effects of Notch signaling inhibition on neurosphere formation of hDPSCs and neuronal differentiation of hDPSCs-neurospheres.

RESULTS

hDPSCs were isolated from third molar teeth. The cultivated hDPSCs highly expressed CD90 and CD44 and minimally presented CD34 and CD45 surface markers. The osteo/adipogenic differentiation of hDPSCs was documented. hDPSCs were cultured in neural induction medium and N-[N-(3,5-difluorophenacetyl-L-alanyl)]-Sphenylglycine t-butyl ester (DAPT) was applied to impede Notch signaling during transformation into spheres or on the formed neurospheres. Our results showed that the size and number of neurospheres decreased and the expression profile of nestin, sox1 and pax6 genes reduced provided DAPT. Treatment of the formed neurospheres with DAPT resulted in the cleaved Notch1 reduction, G0/G1 arrest and a decline in L-lactate production. DAPT significantly reduced hes1 and hey1 genes, while ascl1 and neurogenin2 expressions augmented. The number of MAP2 positive cells improved in the DAPT-treated group.

CONCLUSIONS

Our findings demonstrated the Notch activity in hDPSCs-neurospheres. DAPT treatment positively regulated proneural genes expression and increased neuronal-like differentiation.

Differentiation of Bone Marrow Mesenchymal Stem Cells into Neural Lineage Cells Induced by bFGF-Chitosan Controlled Release System

Bone marrow mesenchymal stem cells undergo differentiation to different lineages with different efficiencies when induced by different factors. We added a bFGF-chitosan controlled release system (bFGF-CCRS) as an inducer into conditioned medium to facilitate the oriented differentiation of BMSCs into neural lineage cells (eventually mature neurons); furthermore, we synchronized BMSCs to the G0/G1 phase via serum starvation to observe the effect of the inducer on the differentiation direction and efficiency. The nonsynchronized group, chitosan alone (not loaded with bFGF) group, soluble bFGF group, and conditioned medium group served as controls, and we observed the dynamic process of differentiation of BMSCs into neural lineage cells at different time points after the beginning of coculture. We analyzed the binding patterns of bFGF and chitosan and assayed the expression differences of key factors (FGFR1, ERK, and c-fos) and molecular switches (BTG2) that regulate the transformation from cell proliferation to differentiation. We also investigated the potential molecular mechanism of BMSC differentiation into neural lineage cells at a high percentage when induced by bFGF-CCRS.

Mesenchymal stem cell basic research and applications in dog medicine

The stem cells, owing to their special characteristics like self-renewal, multiplication, homing, immunomodulation, anti-inflammatory, and dedifferentiation are considered to carry an "all-in-one-solution" for diverse clinical problems. However, the limited understanding of cellular physiology currently limits their definitive therapeutic use. Among various stem cell types, currently mesenchymal stem cells are extensively studied for dog clinical applications owing to their readily available sources, easy harvesting, and ability to differentiate both into mesodermal, as well as extramesodermal tissues. The isolated, culture expanded, and characterized cells have been applied both at preclinical as well as clinical settings in dogs with variable but mostly positive results. The results, though positive, are currently inconclusive and demands further intensive research on the properties and their dependence on the applications. Further, numerous clinical conditions of dog resemble to that of human counterparts and thus, if proved rewarding in the former may act as basis of therapy for the latter. The current review throws some light on dog mesenchymal stem cell properties and their potential therapeutic applications.

Immunocytochemical analysis of valproic acid induced histone H3 and H4 acetylation during differentiation of rat adipose derived stem cells into neuron-like cells

Valproic acid (VPA) is an inhibitor of histone deacetylases (HDACs) that can regulate differentiation and proliferation of stem cells by epigenetic mechanisms. We investigated VPA induced histone H3 and H4 acetylation in adipose derived stem cells (ADSCs) transdifferentiated into neuron-like cells (NLCs). Rat ADSCs were transdifferentiated into neural stem cells (NSCs) that had been generated from neurospheres. The NSCs were differentiated into NLCs by induction with different concentrations of VPA at 24, 48 and 72 h. The NLCs were evaluated using anti-H3 and -H4 antibodies, and ADSCs, NSCs and NLCs were evaluated using immunofluorescence. The ADSCs were immunoreactive to CD90 and CD49d, but not to CD45 and CD31. Both the neurospheres and NSCs were immunostained with nestin and neurofilament 68. The neurospheres expressed Musashi1, Sox2 and Neu N genes as determined by RT-PCR. Our dose-response study indicated that the optimal concentration of VPA was 1 mM at 72 h. Histone acetylation levels of H3 and H4 immunostaining intensities in NLCs were significantly greater than for ADSCs and NSCs. VPA alters H4 and H3 acetylation immunoreactivities of ADSCs transdifferentiated into NLCs.

Tissue source determines the differentiation potentials of mesenchymal stem cells: a comparative study of human mesenchymal stem cells from bone marrow and adipose tissue

Background

Mesenchymal stem cells (MSCs) possess intrinsic regeneration capacity as part of the repair process in response to injury, such as fracture or other tissue injury. Bone marrow and adipose tissue are the major sources of MSCs. However, which cell type is more effective and suitable for cell therapy remains to be answered. The intrinsic molecular mechanism supporting the assertion has also been lacking.

Methods

Human bone marrow-derived MSCs (BMSCs) and adipose tissue-derived MSCs (ATSCs) were isolated from bone marrow and adipose tissue obtained after total hip arthroplasty. ATSCs and BMSCs were incubated in standard growth medium. Trilineage differentiation including osteogenesis, adipogenesis, and chondrogenesis was performed by addition of relevant induction mediums. The expression levels of trilineage differentiation marker genes were evaluated by quantitative RT-PCR. The methylation status of CpG sites of Runx2, PPARγ, and Sox9 promoters were checked by bisulfite sequencing. In addition, ectopic bone formation and calvarial bone critical defect models were used to evaluate the bone regeneration ability of ATSCs and BMSCs in vivo.

Results

The results showed that BMSCs possessed stronger osteogenic and lower adipogenic differentiation potentials compared to ATSCs. There was no significant difference in the chondrogenic differentiation potential. The CpG sites of Runx2 promoter in BMSCs were hypomethylated, while in ATSCs they were hypermethylated. The CpG sites of PPARγ promoter in ATSCs were hypomethylated, while in BMSCs they were hypermethylated. The methylation status of Sox9 promoter in BMSCs was only slightly lower than that in ATSCs.

Conclusions

The epigenetic memory obtained from either bone marrow or adipose tissue favored MSC differentiation along an osteoblastic or adipocytic lineage. The methylation status of the main transcription factors controlling MSC fate contributes to the differential differentiation capacities of different source-derived MSCs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0716-x) contains supplementary material, which is available to authorized users.

Comparison of the neuronal differentiation abilities of bone marrow‑derived and adipose tissue‑derived mesenchymal stem cells

Bone marrow-derived mesenchymal stem cells (BMSCs) and adipose tissue-derived mesenchymal stem cells (ADSCs) are able to differentiate into neuron-like cells when exposed to small molecule compounds, however the specific differences in their neuronal differentiation abilities remain to be fully elucidated. The present study aimed to compare the neuronal differentiation abilities of BMSCs and ADSCs. BMSCs and ADSCs from the same Sprague Dawley rats were isolated and cultured for use. The proliferation capacity was revealed using a cell counting method. Following BMSCs and ADSCs induction by four types of small-molecular compounds, the expression of various neuronal markers and the secretion of several neurotrophic factors were detected by immunofluorescence, western blotting, reverse transcription-quantitative polymerase chain reaction and ELISA. It was demonstrated that the ADSCs exhibited an increased proliferation capacity compared with BMSCs, according to cumulative population doubling analyses. Following a 7-day neuronal induction period, BMSCs and ADSCs exhibited a neuron-like morphology, and were termed neuronal induced (NI)-BMSCs and NI-ADSCs. They expressed neuronal markers including β-tubulin III, microtubule associated protein 2 and choline acetyltransferase. The number of NI-BMSCs that positively expressed the neuronal markers was significantly decreased compared with NI-ADSCs, and the expression and secretion of the neurotrophic factors nerve growth factor and 3′-nucleotidase in NI-BMSCs were additionally decreased compared with NI-ADSCs. The findings of the present study indicated that the neuronal differentiation abilities and neurotrophic factor secretion abilities of ADSCs were increased compared with BMSCs. ADSCs may therefore act as efficient candidates in cell transplantation therapy for diseases and injuries of the nervous system.

Functionalized carbon nanotubes as suitable scaffold materials for proliferation and differentiation of canine mesenchymal stem cells

In the field of regenerative medicine, numerous potential applications of mesenchymal stem cells (MSCs) can be envisaged, due to their ability to differentiate into a range of tissues on the basis of the substrate on which they grow. With the advances in nanotechnology, carbon nanotubes (CNTs) have been widely explored for use as cell culture substrate in tissue engineering applications. In this study, canine bone marrow-derived MSCs were considered as the cellular model for an in vitro study to elucidate the collective cellular processes, using three different varieties of thin films of functionalized carbon nanotubes (COOH-single-walled CNTs [SWCNTs], COOH-multiwalled CNTs [MWCNTs] and polyethylene glycol [PEG]-SWCNTs), which were spray dried onto preheated cover slips. Cells spread out better on the CNT films, resulting in higher cell surface area and occurrence of filopodia, with parallel orientation of stress fiber bundles. Canine MSCs proliferated at a slower rate on all types of CNT substrates compared to the control, but no decline in cell number was noticed during the study period. Expression of apoptosis-associated genes decreased on the CNT substrates as time progressed. On flow cytometry after AnnexinV-fluorescein isothiocyanate/propidium iodide (PI) staining, total number of apoptotic and necrotic cells remained lower in COOH-functionalized films compared to PEG-functionalized ones. Collectively, these results indicate that COOH-MWCNT substrate provided an environment of low cytotoxicity. Canine MSCs were further induced to differentiate along osteogenic, chondrogenic, and neuronal lineages by culturing under specific differentiation conditions. The cytochemical and immunocytochemical staining results, as well as the expression of the bone marker genes, led us to hypothesize that the COOH-MWCNT substrate acted as a better cue, accelerating the osteogenic differentiation process. However, while chondrogenesis was promoted by COOH-SWCNT, neuronal differentiation was promoted by both COOH-SWNCT and COOH-MWCNT. Taken together, these findings suggest that COOH-functionalized CNTs represent a promising scaffold component for future utilization in the selective differentiation of canine MSCs in regenerative medicine.

New Insights into the Neural Differentiation Potential of Canine Adipose Tissue-Derived Mesenchymal Stem Cells

Adipose tissue-derived stem cells (ASCs) can be obtained from different adipose tissue sources within the body. It is an abundant cell pool, easily accessible, suitable for cultivation and expansion in vitro and preparation for therapeutic approaches. Amongst these therapeutic approaches are tissue engineering and nervous system disorders such as spinal cord injuries. For such treatment, ASCs have to be reliably differentiated in to the neuronal direction. Therefore, we investigated the neural differentiation potential of ASCs using protocols with neurogenic inductors such as valproic acid and forskolin, while dog brain tissue served as control. Morphological changes could already be noticed 1 h after neuronal induction. Gene expression analysis revealed that the neuronal markers nestin and βIII-tubulin as well as MAP2 were expressed after induction of neuronal differentiation. Additionally, the expression of the neurotrophic factors NGF, BDNF and GDNF was determined. Some of the neuronal markers and neurotrophic factors were already expressed in undifferentiated cells. Our findings point out that ASCs can reliably be differentiated into the neuronal lineage; therefore, these cells are a suitable cell source for cell transplantation in disorders of the central nervous system. Follow-up studies would show the clinical benefit of these cells after transplantation.

Stem cell therapies in age-related neurodegenerative diseases and stroke

Aging, a complex process associated with various structural, functional and metabolic changes in the brain, is an important risk factor for neurodegenerative diseases and stroke. These diseases share similar neuropathological changes, such as the formation of misfolded proteins, oxidative stress, loss of neurons and synapses, dysfunction of the neurovascular unit (NVU), reduction of self-repair capacity, and motor and/or cognitive deficiencies. In addition to gray matter dysfunction, the plasticity and repair capacity of white matter also decrease with aging and contribute to neurodegenerative diseases. Aging not only renders patients more susceptible to these disorders, but also attenuates their self-repair capabilities. In addition, low drug responsiveness and intolerable side effects are major challenges in the prevention and treatment of senile diseases. Thus, stem cell therapies-characterized by cellular plasticity and the ability to self-renew-may be a promising strategy for aging-related brain disorders. Here, we review the common pathophysiological changes, treatments, and the promises and limitations of stem cell therapies in age-related neurodegenerative diseases and stroke.

Bone morphogenetic protein 4 and bone morphogenetic protein receptor expression in the pituitary gland of adult dogs in healthy condition and with ACTH-secreting pituitary adenoma

The purpose of this study was to investigate the expression of bone morphogenetic protein 4 (BMP4) and its receptors, bone morphogenetic protein receptor I (BMPRI) and BMPRII, in the pituitary gland of healthy adult dogs and in those with ACTH-secreting pituitary adenoma. Quantitative polymerase chain reaction analysis showed that the BMP4 messenger RNA expression level in the ACTH-secreting pituitary adenoma samples was significantly lower than that in the normal pituitary gland samples (P = 0.03). However, there were no statistically significant differences between samples with respect to the messenger RNA expression levels of the receptors BMPRIA, BMPRIB, and BMPRII. Double-immunofluorescence analysis of the normal canine pituitary showed that BMP4 was localized in the thyrotroph (51.3 ± 7.3%) and not the corticotroph cells. By contrast, BMPRII was widely expressed in the thyrotroph (19.9 ± 5.2%) and somatotroph cells (94.7 ± 3.6%) but not in the corticotroph cells (P < 0.001, thyrotroph cells vs somatotroph cells). Similarly, in ACTH-secreting pituitary adenoma, BMP4 and BMPRII were not expressed in the corticotroph cells. Moreover, the percentage of BMP4-positive cells was also significantly reduced in the thyrotroph cells of the surrounding normal pituitary tissue obtained from the resected ACTH-secreting pituitary adenoma (8.3 ± 7.9%) compared with that in normal canine pituitary (P < 0.001). BMP4 has been reported to be expressed in corticotroph cells in the human pituitary gland. Therefore, the results of this study reveal a difference in the cellular pattern of BMP4-positive staining in the pituitary gland between humans and dogs and further revealed the pattern of BMPRII-positive staining in the dog pituitary gland. These species-specific differences regarding BMP4 should be considered when using dogs as an animal model for Cushing's disease.

Adipose Stem Cells Display Higher Regenerative Capacities and More Adaptable Electro-Kinetic Properties Compared to Bone Marrow-Derived Mesenchymal Stromal Cells

Adipose stem cells (ASCs) have recently emerged as a more viable source for clinical applications, compared to bone-marrow mesenchymal stromal cells (BM-MSCs) because of their abundance and easy access. In this study we evaluated the regenerative potency of ASCs compared to BM-MSCs. Furthermore, we compared the dielectric and electro-kinetic properties of both types of cells using a novel Dielectrophoresis (DEP) microfluidic platform based on a printed circuit board (PCB) technology. Our data show that ASCs were more effective than BM-MSCs in promoting neovascularization in an animal model of hind-limb ischemia. When compared to BM-MSCs, ASCs displayed higher resistance to hypoxia-induced apoptosis, and to oxidative stress-induced senescence, and showed more potent proangiogenic activity. mRNA expression analysis showed that ASCs had a higher expression of Oct4 and VEGF than BM-MSCs. Furthermore, ASCs showed a remarkably higher telomerase activity. Analysis of the electro-kinetic properties showed that ASCs displayed different traveling wave velocity and rotational speed compared to BM-MSCs. Interestingly, ASCs seem to develop an adaptive response when exposed to repeated electric field stimulation. These data provide new insights into the physiology of ASCs, and evidence to their potential superior potency compared to marrow MSCs as a source of stem cells.

Comparative analysis of human mesenchymal stem cells from bone marrow and adipose tissue under xeno-free conditions for cell therapy

INTRODUCTION

Mesenchymal stem cells (MSCs) are promising candidates for cell-based therapies. Human platelet lysate represents an efficient alternative to fetal bovine serum for clinical-scale expansion of MSCs. Different media used in culture processes should maintain the biological characteristics of MSCs during multiple passages. However, bone marrow-derived MSCs and adipose tissue-derived MSCs have not yet been directly compared with each other under human platelet lysate conditions. This study aims to conduct a direct head-to-head comparison of the biological characteristics of the two types of MSCs under human platelet lysate-supplemented culture conditions for their ability to be used in regenerative medicine applications.

METHODS

The bone marrow- and adipose tissue-derived MSCs were cultured under human platelet lysate conditions and their biological characteristics evaluated for cell therapy (morphology, immunophenotype, colony-forming unit-fibroblast efficiency, proliferation capacity, potential for mesodermal differentiation, secreted proteins, and immunomodulatory effects).

RESULTS

Under human platelet lysate-supplemented culture conditions, bone marrow- and adipose tissue-derived MSCs exhibited similar fibroblast-like morphology and expression patterns of surface markers. Adipose tissue-derived MSCs had greater proliferative potential than bone marrow-derived MSCs, while no significantly difference in colony efficiency were observed between the two types of cells. However, bone marrow-derived MSCs possessed higher capacity toward osteogenic and chondrogenic differentiation compared with adipose tissue-derived MSCs, while similar adipogenic differentiation potential wase observed between the two types of cells. There were some differences between bone marrow- and adipose tissue-derived MSCs for several secreted proteins, such as cytokine (interferon-γ), growth factors (basic fibroblast growth factor, hepatocyte growth factor, and insulin-like growth factor-1), and chemokine (stem cell-derived factor-1). Adipose tissue-derived MSCs had more potent immunomodulatory effects than bone marrow-derived MSCs.

CONCLUSIONS

Adipose tissue-derived MSCs have biological advantages in the proliferative capacity, secreted proteins (basic fibroblast growth factor, interferon-γ, and insulin-like growth factor-1), and immunomodulatory effects, but bone marrow-derived MSCs have advantages in osteogenic and chondrogenic differentiation potential and secreted proteins (stem cell-derived factor-1 and hepatocyte growth factor); these biological advantages should be considered systematically when choosing the MSC source for specific clinical application.

Canine Mesenchymal Stem Cell Potential and the Importance of Dog Breed: Implication for Cell-Based Therapies

The study of canine bone marrow-derived mesenchymal stem cells (MSCs) has a prominent position in veterinary cell-based applications. Yet the plethora of breeds, their different life spans, and interbreed variations provide unclearness on what can be achieved specifically by such therapies. In this study, we compared a set of morphological, physiological, and genetic markers of MSCs derived from large dog breeds, namely, Border collie, German shepherd, Labrador, Malinois, Golden retriever, and Hovawart. We compared colony-forming units (CFUs) assay, population doubling time (PDT), senescence-associated β-galactosidase (SA-β-gal) activity, telomere length, and gene expression of MSCs, as well as the ability of cells to differentiate to osteogenic, adipogenic, and chondrogenic phenotypes. The influence of the culture media α-MEM, low-glucose DMEM, and high-glucose DMEM, used in cell isolation and expansion, was investigated in the presence and absence of basic fibroblast growth factor (bFGF). Initial cell yield was not affected by culturing medium, but MSCs expanded best in α-MEM supplemented with bFGF. After isolation, the number of MSCs was similar among breeds--as shown by equivalent CFUs--except in the Hovawart samples, which had fivefold less CFU. Telomere lengths were similar among breeds. MSCs divided actively only for 4 weeks in culture (PDT = ∼50 h/division), except Border collie cells divided for a longer time than cells from other groups. The percentage of senescent cells increased linearly in all breeds with time, with a faster rate in German shepherd, Labrador, and Golden retriever. Border collie cells underwent efficient osteogenic differentiation, Hovawart cells performed the best in chondrogenic differentiation, and Labrador cells in both, while German shepherd cells had the lower differentiation potential. MSCs from all breeds preserved the same adipogenic differentiation potential. In conclusion, despite variations, isolated MSCs can be expanded and differentiated in vitro, and all breeds are eligible for MSC-based therapies.

Transplantation of purified autologous leukapheresis-derived CD34+ and CD133+ stem cells for patients with chronic spinal cord injuries: long-term evaluation of safety and efficacy

This study is aimed at describing a novel method for treating patients with chronic complete spinal cord injuries (SCIs) by utilizing autologous, purified CD34(+) and CD133(+) stem cells (SCs). The study focuses on the safety and efficacy of transplanting unmanipulated, autologous, purified stem cells in treated patients during a 5-year follow-up period. In this report, 19 patients were included (16 males and 3 females) who presented with a complete SCI (ASIA-A) in the thoracic region. The patients' endogenous cells were mobilized with subcutaneous granulocyte-colony-stimulating factor (G-CSF) for 5 days. We utilized the CliniMACS magnetic separation system to purify leukapheresis-derived CD34(+) and CD133(+) SCs. Purified SCs were directly transplanted into the SCI site. Patients were then monitored and followed for up to 5 years. On average, 76 × 10(6) purified SCs were obtained from each patient, with 95.2% purity and >98% viability. SC transplantation into the cyst cavity or the subarachnoid space was successful and well tolerated in all 19 patients and did not cause any allergic or inflammatory reactions within the CNS in the early or late periods after transplantation. Ten patients (53%) showed no improvement after 42-60 months (ASIA-A), while seven patients (37%) demonstrated segmental sensory improvement (ASIA-B), and the remaining two patients (10%) had motor improvement (ASIA-C). This study presents a safe method for transplanting specific populations of purified autologous SCs that can be used to treat SCIs in a clinical setting. The results may be utilized as a stepping-stone for future investigations in the field of regenerative medicine for treatment of SCIs and other neurological diseases. This manuscript is published as part of the International Association of Neurorestoratology (IANR) special issue of Cell Transplantation.

Acute spinal cord injury: tetraplegia and paraplegia in small animals

Spinal cord injury (SCI) is a common problem in animals for which definitive treatment is lacking, and information gained from its study has benefit for both companion animals and humans in developing new therapeutic approaches. This review provides an overview of the main concepts that are useful for clinicians in assessing companion animals with severe acute SCI. Current available advanced ancillary tests and those in development are reviewed. In addition, the current standard of care for companion animals following SCI and recent advances in the development of new therapies are presented, and new predictors of recovery discussed.

Differentiation of canine bone marrow stromal cells into voltage- and glutamate-responsive neuron-like cells by basic fibroblast growth factor

We investigated the in vitro differentiation of canine bone marrow stromal cells (BMSCs) into voltage- and glutamate-responsive neuron-like cells. BMSCs were obtained from the bone marrow of healthy beagle dogs. Canine BMSCs were incubated with the basal medium for neurons containing recombinant human basic fibroblast growth factor (bFGF; 100 ng/ml). The viability of the bFGF-treated cells was assessed by a trypan blue exclusion assay, and the morphology was monitored. Real-time RT-PCR was performed to evaluate mRNA expression of neuronal, neural stem cell and glial markers. Western blotting and immunocytochemical analysis for the neuronal markers were performed to evaluate the protein expression and localization. The Ca(2+) mobilization of the cells was evaluated using the Ca(2+) indicator Fluo3 to monitor Ca(2+) influx. To investigate the mechanism of bFGF-induced neuronal differentiation, the fibroblast growth factor receptor inhibitor, the phosphoinositide 3-kinase inhibitor or the Akt inhibitor was tested. The bFGF treatment resulted in the maintenance of the viability of canine BMSCs for 10 days, in the expression of neuronal marker mRNAs and proteins and in the manifestation of neuron-like morphology. Furthermore, in the bFGF-treated BMSCs, a high concentration of KCl and L-glutamate induced an increase in intracellular Ca(2+) levels. Each inhibitor significantly attenuated the bFGF-induced increase in neuronal marker mRNA expression. These results suggest that bFGF contributes to the differentiation of canine BMSCs into voltage- and glutamate-responsive neuron-like cells and may lead to the development of new cell-based treatments for neuronal diseases.

Hip osteoarthritis in dogs: a randomized study using mesenchymal stem cells from adipose tissue and plasma rich in growth factors

Purpose: The aim of this study was to compare the efficacy and safety of a single intra-articular injection of adipose mesenchymal stem cells (aMSCs) versus plasma rich in growth factors (PRGF) as a treatment for reducing symptoms in dogs with hip osteoarthritis (OA). Methods: This was a randomized, multicenter, blinded, parallel group. Thirty-nine dogs with symptomatic hip OA were assigned to one of the two groups, to receive aMSCs or PRGF. The primary outcome measures were pain and function subscales, including radiologic assessment, functional limitation and joint mobility. The secondary outcome measures were owners’ satisfaction questionnaire, rescue analgesic requirement and overall safety. Data was collected at baseline, then, 1, 3 and 6 months post-treatment. Results: OA degree did not vary within groups. Functional limitation, range of motion (ROM), owner’s and veterinary investigator visual analogue scale (VAS), and patient’s quality of life improved from the first month up to six months. The aMSCs group obtained better results at 6 months. There were no adverse effects during the study. Our findings show that aMSCs and PRGF are safe and effective in the functional analysis at 1, 3 and 6 months; provide a significant improvement, reducing dog’s pain, and improving physical function. With respect to basal levels for every parameter in patients with hip OA, aMSCs showed better results at 6 months.

The potential of mesenchymal stem cell in prion research

Scrapie and bovine spongiform encephalopathy are fatal neurodegenerative diseases caused by the accumulation of a misfolded protein (PrP(res)), the pathological form of the cellular prion protein (PrP(C)). For the last decades, prion research has greatly progressed, but many questions need to be solved about prion replication mechanisms, cell toxicity, differences in genetic susceptibility, species barrier or the nature of prion strains. These studies can be developed in murine models of transmissible spongiform encephalopathies, although development of cell models for prion replication and sample titration could reduce economic and timing costs and also serve for basic research and treatment testing. Some murine cell lines can replicate scrapie strains previously adapted in mice and very few show the toxic effects of prion accumulation. Brain cell primary cultures can be more accurate models but are difficult to develop in naturally susceptible species like humans or domestic ruminants. Stem cells can be differentiated into neuron-like cells and be infected by prions. However, the use of embryo stem cells causes ethical problems in humans. Mesenchymal stem cells (MSCs) can be isolated from many adult tissues, including bone marrow, adipose tissue or even peripheral blood. These cells differentiate into neuronal cells, express PrP(C) and can be infected by prions in vitro. In addition, in the last years, these cells are being used to develop therapies for many diseases, including neurodegenerative diseases. We review here the use of cell models in prion research with a special interest in the potential use of MSCs.

Valproic acid, a histone deacetylase inhibitor, decreases proliferation of and induces specific neurogenic differentiation of canine adipose tissue-derived stem cells

Adipose tissue-derived stem cells (ADSCs) isolated from adult tissue have pluripotent differentiation and self-renewal capability. The tissue source of ADSCs can be obtained in large quantities and with low risks, thus highlighting the advantages of ADSCs in clinical applications. Valproic acid (VPA) is a widely used antiepileptic drug, which has recently been reported to affect ADSC differentiation in mice and rats; however, few studies have been performed on dogs. We aimed to examine the in vitro effect of VPA on canine ADSCs. Three days of pretreatment with VPA decreased the proliferation of ADSCs in a dose-dependent manner; VPA concentrations of 4 mM and above inhibited the proliferation of ADSCs. In parallel, VPA increased p16 and p21 mRNA expression, suggesting that VPA attenuated the proliferative activity of ADSCs by activating p16 and p21. Furthermore, the effects of VPA on adipogenic, osteogenic or neurogenic differentiation were investigated morphologically. VPA pretreatment markedly promoted neurogenic differentiation, but suppressed the accumulation of lipid droplets and calcium depositions. These modifications of ADSCs by VPA were associated with a particular gene expression profile, viz., an increase in neuronal markers, that is, NSE, TUBB3 and MAP2, a decrease in the adipogenic marker, LPL, but no changes in osteogenic markers, as estimated by reverse transcription-PCR analysis. These results suggested that VPA is a specific inducer of neurogenic differentiation of canine ADSCs and is a useful tool for studying the interaction between chromatin structure and cell fate determination.