1,721,080 research outputs found
By the Skin of Your Teeth: A Subcutaneous Mouse Model to Study Pulp Regeneration
No full textExiting developments in tissue engineering and new insights in stem cell biology have led to new possible strategies for the regeneration of damaged tissues in the oral cavity. The regeneration of the pulp–dentin complex regeneration in particular, has drawn the attention of many researchers because of the high clinical needs. While it is still important to perform in vitro research using a wide variety of cells, scaffolds and growth factors, it is also critical to have a reliable animal model for preclinical trials. In this chapter, we describe a mouse model in which a scaffold resembling a tooth containing dental pulp cells is implanted subcutaneously. We also describe which histological stainings could be used to examine blood vessel formation and the regeneration of the pulp–dentin complex
Proteostasis plays an important role in demyelinating Charcot Marie Tooth disease
No full textType 1 Charcot-Marie-Tooth disease (CMT1) is the most common demyelinating peripheral neuropathy. Patients suffer from progressive muscle weakness and sensory problems. The underlying disease mechanisms of CMT1 are still unclear and no therapy is currently available, hence patients completely rely on supportive care. Balancing protein levels is a complex multistep process fundamental to maintain cells in their healthy state and a disrupted proteostasis is a hallmark of several neurodegenerative diseases. When protein misfolding occurs, protein quality control systems are activated such as chaperones, the lysosomal-autophagy system and proteasomal degradation to ensure proper degradation. However, in pathological circumstances, these mechanisms are overloaded and thereby become inefficient to clear the load of misfolded proteins. Recent evidence strongly indicates that a disbalance in proteostasis plays an important role in several forms of CMT1. In this review, we present an overview of the protein quality control systems, their role in CMT1, and potential treatment strategies to restore proteostasis.KL is PhD fellow funded by “Fonds Wetenschappelijk Onderzoek” (FWO: “Research Foundation Flanders”; 11A4120N & 11A4122N) and by the “Special Research Fund” (BOF) of Hasselt University (R-10491). TVG is a Junior postdoc fellow funded by “Fonds Wetenschappelijk Onderzoek” (FWO: “Research Foundation Flanders”; 12Z2620N)
The Effect of Leukocyte- and Platelet-Rich Fibrin on Central and Peripheral Nervous System Neurons-Implications for Biomaterial Applicability
No full textLeukocyte- and Platelet-Rich Fibrin (L-PRF) is a second-generation platelet concentrate that is prepared directly from the patient's own blood. It is widely used in the field of regenerative medicine, and to better understand its clinical applicability we aimed to further explore the biological properties and effects of L-PRF on cells from the central and peripheral nervous system. To this end, L-PRF was prepared from healthy human donors, and confocal, transmission, and scanning electron microscopy as well as secretome analysis were performed on these clots. In addition, functional assays were completed to determine the effect of L-PRF on neural stem cells (NSCs), primary cortical neurons (pCNs), and peripheral dorsal root ganglion (DRG) neurons. We observed that L-PRF consists of a dense but porous fibrin network, containing leukocytes and aggregates of activated platelets that are distributed throughout the clot. Antibody array and ELISA confirmed that it is a reservoir for a plethora of growth factors. Key molecules that are known to have an effect on neuronal cell functions such as brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), vascular endothelial growth factor (VEGF), and platelet-derived growth factor (PDGF) were slowly released over time from the clots. Next, we found that the L-PRF secretome had no significant effect on the proliferative and metabolic activity of NSCs, but it did act as a chemoattractant and improved the migration of these CNS-derived stem cells. More importantly, L-PRF growth factors had a detrimental effect on the survival of pCNs, and consequently, also interfered with their neurite outgrowth. In contrast, we found a positive effect on peripheral DRG neurons, and L-PRF growth factors improved their survival and significantly stimulated the outgrowth and branching of their neurites. Taken together, our study demonstrates the positive effects of the L-PRF secretome on peripheral neurons and supports its use in regenerative medicine but care should be taken when using it for CNS applications
The sphingosine-1-phosphate receptor 1 modulator ponesimod repairs cuprizone-induced demyelination and induces oligodendrocyte differentiation
No full textSphingosine-1-phosphate receptor (S1PR) modulators are clinically used to treat relapse-remitting multiple sclerosis (MS) and the early phase of progressive MS when inflammation still prevails. In the periphery, S1PR modulators prevent lymphocyte egress from lymph nodes, hence hampering neuroinflammation. Recent findings suggest a role for S1PR modulation in remyelination. As the Gi alpha-coupled S1P1 subtype is the most prominently expressed S1PR in oligodendrocyte precursor cells (OPCs), selective modulation (functional antagonism) of S1P1 may have direct effects on OPC functionality. We hypothesized that functional antagonism of S1P1 by ponesimod induces remyelination by boosting OPC differentiation. In the cuprizone mouse model of demyelination, we found ponesimod to decrease the latency time of visual evoked potentials compared to vehicle conditions, which is indicative of functional remyelination. In addition, the Y maze spontaneous alternations test revealed that ponesimod reversed cuprizone-induced working memory deficits. Myelin basic protein (MBP) immunohistochemistry and transmission electron microscopy of the corpus callosum revealed an increase in myelination upon ponesimod treatment. Moreover, treatment with ponesimod alone or in combination with A971432, an S1P5 monoselective modulator, significantly increased primary mouse OPC differentiation based on O4 immunocytochemistry. In conclusion, S1P1 functional antagonism by ponesimod increases remyelination in the cuprizone model of demyelination and significantly increases OPC differentiation in vitro.Ponesimod reverses a cuprizone-induced working memory deficit, restores the cuprizone-induced delay in latency time of the optic pathway, and enhances remyelination after cuprizone intoxication in vivo. Furthermore, ponesimod enhances differentiation of oligodendrocyte precursor cells into mature oligodendrocytes in vitro.imag
Altered lysosomal abundance and activity in Charcot-Marie-Tooth disease type 1A (late breaking abstract)
No full textSafety and Homing of Human Dental Pulp Stromal Cells in Head and Neck Cancer
No full textBACKGROUND: Head and neck cancer (HNC) is one of the most common cancers, associated with a huge mortality and morbidity. In order to improve patient outcomes, more efficient and targeted therapies are essential. Bone marrow-derived mesenchymal stromal cells (BM-MSCs) express tumour homing capacity, which could be exploited to target anti-cancer drug delivery to the tumour region and reduce adverse side-effects. Nevertheless, dental pulp stromal cells (DPSCs), an MSC-like population present in teeth, could offer important clinical benefits because of their easy isolation and superior proliferation compared to BM-MSCs. Therefore, we aimed to elucidate the tumour homing and safe usage of DPSCs to treat HNC. METHODS: The in vivo survival as well as the effect of intratumourally administered DPSCs on tumour aggressiveness was tested in a HNC xenograft mouse model by using bioluminescence imaging (BLI), (immuno)histology and qRT-PCR. Furthermore, the in vitro and in vivo tumour homing capacity of DPSCs towards a HNC cell line were evaluated by a transwell migration assay and BLI, respectively. RESULTS: Intratumourally injected DPSCs survived for at least two weeks in the tumour micro-environment and had no significant influence on tumour morphology, growth, angiogenesis and epithelial-to-mesenchymal transition. In addition, DPSCs migrated towards tumour cells in vitro, which could not be confirmed after their in vivo intravenous, intraperitoneal or peritumoural injection under the tested experimental conditions. CONCLUSIONS: Our research suggests that intratumourally delivered DPSCs might be used as safe factories for the continuous delivery of anti-cancer drugs in HNC. Nevertheless, further optimization as well as efficacy studies are necessary to understand and improve in vivo tumour homing and determine the optimal experimental set-up of stem cell-based cancer therapies, including dosing and timing.sponsorship: G.M. was supported by 'Bijzonder Onderzoeksfonds' of Hasselt University (BOF, BOF16DOC06). M.L.M. was funded by 'Bijzonder Onderzoeksfonds' and 'Fonds Special de Recherche' (BOF16DOCNA02-FSR-confin UHasselt-UNamur). This research was further supported by research grants to I.L., U.H., A.B. and E.W. fromthe Research Foundation Flanders ('Fonds Wetenschappelijk Onderzoek Vlaanderen (FWO)', grant numbers G0C1916FWO, 1517916 N and G0A7514N), BOF of Hasselt University (BOF20TT04), Limburg Cancer foundation ('Limburgs kankerfonds' LIKAF) and KU Leuven for PF 10/017 IMIR. The funding bodies played no role in study design, data collection, analysis and interpretation, or writing of the manuscript. ('Bijzonder Onderzoeksfonds' of Hasselt University (BOF)|BOF16DOC06, Bijzonder Onderzoeksfonds, Fonds Special de Recherche|BOF16DOCNA02-FSR-confin UHasselt-UNamur, Research Foundation Flanders ('Fonds Wetenschappelijk Onderzoek Vlaanderen (FWO)'|G0C1916FWO, Research Foundation Flanders ('Fonds Wetenschappelijk Onderzoek Vlaanderen (FWO)'|1517916 N, Research Foundation Flanders ('Fonds Wetenschappelijk Onderzoek Vlaanderen (FWO)'|G0A7514N, BOF of Hasselt University|BOF20TT04, Limburg Cancer foundation ('Limburgs kankerfonds' LIKAF), KU Leuven|PF 10/017 IMIR)status: Publishe
Expression Pattern of Basal Markers in Human Dental Pulp Stem Cells and Tissue
Full text linkDental pulp stem cells (DPSC) have been characterized as a multipotent stem cell population, with the ability to differentiate into mesodermal and neural cell lineages. Although 'de novo' expression of neural markers after differentiation is mostly considered as proof of differentiation, expression of these markers in undifferentiated DPSC is not well described. Therefore, an immunocytochemical analysis was performed to evaluate the neural marker expression of undifferentiated human DPSC (hDPSC) in in vitro cultures. Undifferentiated hDPSC uniformly expressed neural markers β-III-tubulin, S100 protein and synaptophysin. A subset of the population showed a positive immune-reactivity for galactocerebroside, neurofilament and nerve growth factor receptor p75. Furthermore, the location of possible stem cell niches, present in young dental pulp tissue, was determined by means of immunohistochemistry based on mesenchymal and neural marker expression. The results demonstrated the presence of a perivascular niche and a second stem cell niche at the cervical area. In adult dental pulp, only a perivascular niche could be observed. Based on the expression of neural markers in naïve DPSC, it has to be taken into account that not only the marker expression upon neural differentiation must be analyzed, but an ultrastructural analysis of the morphological changes and functional studies must also be performed to confirm a successful differentiation.sponsorship: The authors of the manuscript are very grateful to Marc Jans and Jeanine Santermans for their dedicated technical assistance. A.B. received a postdoctoral grant from the Fonds voor Wetenschappelijk Onderzoek-Vlaanderen. (Fonds voor Wetenschappelijk Onderzoek-Vlaanderen)status: Publishe
Ultrastructural evidence for multi-lineage differentiation of human dental pulp stem cells
No full textMesenchymal stemm cells (MSCs) are one of the most promising stem cell types due to their availability and relatively simple requirements for in vitro expansion and genetic manipulation. Besides the well-characterized MSCs derived from bone marrow, there is growing eveidence suggesting that dental pulp and the umbilical cord matrix both contain a substantial amount of cells having propertes similar to those of MSCs. In order to assess the potential of dental pulp-derived MSCs(DPSC) and umbilical cord-derived MSCs(UCSC) in future clinical applications, it is essential to gain more insight into their differentiation capacity and to evaluate the tissues formed by these cells. In the present study, the morphological and ultrastructural characteristics of DPSC and UCSC induced towards osteogenic, adipogenic, and chondrogenic lineages were investigated. Cultured DPSC and UCSC showed a similar expression pattern of antigens characteristic of MSCs including CD105, CD29, CD44, CD146, and STRO-1. Under appropriate culture conditions, both DPSC and UCSC showed chondrogenic and osteogenic potential. Adipogenesis could be only partially induced in DPSC resulting in the de novo expression of fatty acid binding protein (FABP), whereas UCSC expressed FABP combined with a very high accumulation of lipid droplets in the cytoplasm. Our results demonstrate, at the biochemical and ultrastructural level, that DPSC display at least bilineage potential, whereas UCSC, which are developmentally more primitive cells, show trilineage potential. We emphasize that transmission electron microscopical analysis is useful to elucidate detailed structural information and provides indisputable evidence of differentiation. These findings highlight their potential therapeutic value for cell-based tissue engineering
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