ResearchPad - tissue-engineering-and-regenerative-medicine https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Functional restoration of ex vivo model of pylorus: Co‐injection of neural progenitor cells and interstitial cells of Cajal]]> https://www.researchpad.co/article/elastic_article_6468 An interstitial cell of Cajal (ICC)‐ and neural progenitor cell (NPCs)‐depleted ex vivo neuromuscular dysfunctional pylorus model was developed. The study demonstrated that simultaneous delivery of ICCs, and NPCs could be used as an effective method to promote survival, differentiation, and integration of NPCs in a denervated and dysfunctional pylorus. The resulted reinstatement and restoration of functionality would be critical in the treatment of pylorus dysfunctionality.

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<![CDATA[Exosomal 2′,3′‐CNP from mesenchymal stem cells promotes hippocampus CA1 neurogenesis/neuritogenesis and contributes to rescue of cognition/learning deficiencies of damaged brain]]> https://www.researchpad.co/article/N852b96c8-0f2a-48c6-9317-afb24cc91d5c

Abstract

Mesenchymal stem cells (MSCs) have been used in clinical studies to treat neurological diseases and damage. However, implanted MSCs do not achieve their regenerative effects by differentiating into and replacing neural cells. Instead, MSC secretome components mediate the regenerative effects of MSCs. MSC‐derived extracellular vesicles (EVs)/exosomes carry cargo responsible for rescuing brain damage. We previously showed that EP4 antagonist‐induced MSC EVs/exosomes have enhanced regenerative potential to rescue hippocampal damage, compared with EVs/exosomes from untreated MSCs. Here we show that EP4 antagonist‐induced MSC EVs/exosomes promote neurosphere formation in vitro and increase neurogenesis and neuritogenesis in damaged hippocampi; basal MSC EVs/exosomes do not contribute to these regenerative effects. 2′,3′‐Cyclic nucleotide 3′‐phosphodiesterase (CNP) levels in EP4 antagonist‐induced MSC EVs/exosomes are 20‐fold higher than CNP levels in basal MSC EVs/exosomes. Decreasing elevated exosomal CNP levels in EP4 antagonist‐induced MSC EVs/exosomes reduced the efficacy of these EVs/exosomes in promoting β3‐tubulin polymerization and in converting toxic 2′,3′‐cAMP into neuroprotective adenosine. CNP‐depleted EP4 antagonist‐induced MSC EVs/exosomes lost the ability to promote neurogenesis and neuritogenesis in damaged hippocampi. Systemic administration of EV/exosomes from EP4‐antagonist derived MSC EVs/exosomes repaired cognition, learning, and memory deficiencies in mice caused by hippocampal damage. In contrast, CNP‐depleted EP4 antagonist‐induced MSC EVs/exosomes failed to repair this damage. Exosomal CNP contributes to the ability of EP4 antagonist‐elicited MSC EVs/exosomes to promote neurogenesis and neuritogenesis in damaged hippocampi and recovery of cognition, memory, and learning. This experimental approach should be generally applicable to identifying the role of EV/exosomal components in eliciting a variety of biological responses.

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<![CDATA[Antibacterial activity of human mesenchymal stem cells mediated directly by constitutively secreted factors and indirectly by activation of innate immune effector cells]]> https://www.researchpad.co/article/N5e1a696f-7bd1-44a9-bb1d-95034d4e0514

Abstract

Mesenchymal stem cells (MSC) have been shown to improve wound healing and suppress inflammatory immune responses. Newer research also indicates that MSC exhibit antimicrobial activity, although the mechanisms underlying this activity have not been fully elucidated. Therefore, we conducted in vitro and in vivo studies to examine the ability of resting and activated MSC to kill bacteria, including multidrug resistant strains. We investigated direct bacterial killing mechanisms and the interaction of MSC with host innate immune responses to infection. In addition, the activity of MSC against chronic bacterial infections was investigated in a mouse biofilm infection model. We found that MSC exhibited high levels of spontaneous direct bactericidal activity in vitro. Moreover, soluble factors secreted by MSC inhibited Staphylococcus aureus biofilm formation in vitro and disrupted the growth of established biofilms. Secreted factors from MSC also elicited synergistic killing of drug‐resistant bacteria when combined with several major classes of antibiotics. Other studies demonstrated interactions of activated MSC with host innate immune responses, including triggering of neutrophil extracellular trap formation and increased phagocytosis of bacteria. Finally, activated MSC administered systemically to mice with established S. aureus biofilm infections significantly reduced bacterial numbers at the wound site and improved wound healing when combined with antibiotic therapy. These results indicate that MSC generate multiple direct and indirect, immunologically mediated antimicrobial activities that combine to help eliminate chronic bacterial infections when the cells are administered therapeutically.

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<![CDATA[Multiple doses of adipose tissue‐derived mesenchymal stromal cells induce immunosuppression in experimental asthma]]> https://www.researchpad.co/article/N6ceae66a-68dc-4919-a055-933fca68c166

Abstract

In experimental house dust mite (HDM)‐induced allergic asthma, therapeutic administration of a single dose of adipose tissue‐derived mesenchymal stromal cells (MSCs) ameliorates lung inflammation but is unable to reverse remodeling. We hypothesized that multiple doses of MSCs might exert better therapeutic effects by reducing lung inflammation and remodeling but might also result in immunosuppressive effects in experimental asthma. HDM was administered intranasally in C57BL/6 mice. After the last HDM challenge, mice received two or three doses of MSCs (105 cells per day) or saline intravenously. An additional cohort of mice received dexamethasone as a positive control for immunosuppression. Two and three doses of MSCs reduced lung inflammation, levels of interleukin (IL)‐4, IL‐13, and eotaxin; total leukocyte, CD4+ T‐cell, and eosinophil counts in bronchoalveolar lavage fluid; and total leukocyte counts in bone marrow, spleen, and mediastinal lymph nodes. Two and three doses of MSCs also reduced collagen fiber content and transforming growth factor‐β levels in lung tissue; however, the three‐dose regimen was more effective, and reduced these parameters to control levels, while also decreasing α‐actin content in lung tissue. Two and three doses of MSCs improved lung mechanics. Dexamethasone, two and three doses of MSCs similarly increased galectin levels, but only the three‐dose regimen increased CD39 levels in the thymus. Dexamethasone and the three‐dose, but not the two‐dose regimen, also increased levels of programmed death receptor‐1 and IL‐10, while reducing CD4+CD8low cell percentage in the thymus. In conclusion, multiple doses of MSCs reduced lung inflammation and remodeling while causing immunosuppression in HDM‐induced allergic asthma.

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<![CDATA[Amnion membrane hydrogel and amnion membrane powder accelerate wound healing in a full thickness porcine skin wound model]]> https://www.researchpad.co/article/N6fe5b1a2-8c62-4966-8bfb-638935f64341

Abstract

There is a need for effective wound treatments that retain the bioactivity of a cellular treatment, but without the high costs and complexities associated with manufacturing, storing, and applying living biological products. Previously, we developed an amnion membrane‐derived hydrogel and evaluated its wound healing properties using a mouse wound model. In this study, we used a full thickness porcine skin wound model to evaluate the wound‐healing efficacy of the amnion hydrogel and a less‐processed amnion product comprising a lyophilized amnion membrane powder. These products were compared with commercially available amnion and nonamnion wound healing products. We found that the amnion hydrogel and amnion powder treatments demonstrated significant and rapid wound healing, driven primarily by new epithelialization versus closure by contraction. Histological analysis demonstrated that these treatments promote the formation of a mature epidermis and dermis with similar composition to healthy skin. The positive skin regenerative outcomes using amnion hydrogel and amnion powder treatments in a large animal model further demonstrate their potential translational value for human wound treatments.

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<![CDATA[Functional equivalence of stem cell and stem cell‐derived extracellular vesicle transplantation to repair the irradiated brain]]> https://www.researchpad.co/article/N2afc4605-8453-412e-8d67-a50bd3ff74c2

Abstract

Cranial radiotherapy, although beneficial for the treatment of brain tumors, inevitably leads to normal tissue damage that can induce unintended neurocognitive complications that are progressive and debilitating. Ionizing radiation exposure has also been shown to compromise the structural integrity of mature neurons throughout the brain, an effect believed to be at least in part responsible for the deterioration of cognitive health. Past work has shown that cranially transplanted human neural stem cells (hNSCs) or their extracellular vesicles (EVs) afforded long‐term beneficial effects on many of these cognitive decrements. To provide additional insight into the potential neuroprotective mechanisms of cell‐based regenerative strategies, we have analyzed hippocampal neurons for changes in structural integrity and synaptic remodeling after unilateral and bilateral transplantation of hNSCs or EVs derived from those same cells. Interestingly, hNSCs and EVs similarly afforded protection to host neurons, ameliorating the impact of irradiation on dendritic complexity and spine density for neurons present in both the ipsilateral and contralateral hippocampi 1 month following irradiation and transplantation. These morphometric improvements were accompanied by increased levels of glial cell‐derived growth factor and significant attenuation of radiation‐induced increases in postsynaptic density protein 95 and activated microglia were found ipsi‐ and contra‐lateral to the transplantation sites of the irradiated hippocampus treated with hNSCs or hNSC‐derived EVs. These findings document potent far‐reaching neuroprotective effects mediated by grafted stem cells or EVs adjacent and distal to the site of transplantation and support their potential as therapeutic agents to counteract the adverse effects of cranial irradiation.

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<![CDATA[Smurf1 Silencing Using a LNA‐ASOs/Lipid Nanoparticle System to Promote Bone Regeneration]]> https://www.researchpad.co/article/Nca7f098d-0c72-4152-b890-b25978acfac8

Abstract

Despite the great advance of bone tissue engineering in the last few years, repair of bone defects remains a major problem. Low cell engraftment and dose‐dependent side effects linked to the concomitant administration of bone morphogenetic proteins (BMPs) are the main problems currently hindering the clinical use of mesenchymal stem cell (MSC)‐based therapies in this field. We have managed to bypass these drawbacks by combining the silencing the Smurf1 ubiquitin ligase in MSCs with the use of a scaffold that sustainably releases low doses of BMP‐2. In this system, Smurf1 silencing is achieved by using GapmeRs, a clinically safe method that avoids the use of viral vectors, facilitating its translation to the clinic. Here, we show that a single transient transfection with a small quantity of a Smurf1‐specific GapmeR is able to induce a significant level of silencing of the target gene, enough to prime MSCs for osteogenic differentiation. Smurf1 silencing highly increases MSCs responsiveness to BMP‐2, allowing a dramatic reduction of the dose needed to achieve the desired therapeutic effect. The combination of these primed cells with alginate scaffolds designed to sustainably and locally release low doses of BMP‐2 to the defect microenvironment is able to induce the formation of a mature bone matrix both in an osteoporotic rat calvaria system and in a mouse ectopic model. Importantly, this approach also enhances osteogenic differentiation in MSCs from osteoporotic patients, characterized by a reduced bone‐forming potential, even at low BMP doses, underscoring the regenerative potential of this system. stem cells translational medicine 2019;8:1306&1317

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<![CDATA[Characterization and Comparison of Postnatal Rat Meniscus Stem Cells at Different Developmental Stages]]> https://www.researchpad.co/article/N86c1662a-abb9-42a0-9f97-a3fd2537b62b

Abstract

Meniscus‐derived stem cells (MeSCs) are a potential cell source for meniscus tissue engineering. The stark morphological and structural changes of meniscus tissue during development indicate the complexity of MeSCs at different tissue regions and stages of development. In this study, we characterized and compared postnatal rat meniscus tissue and MeSCs at different tissue regions and stages of development. We observed that the rat meniscus tissue exhibited marked changes in tissue morphology during development, with day 7 being the most representative time point of different developmental stages. All rat MeSCs displayed typical stem cell characteristics. Rat MeSCs derived from day 7 inner meniscus tissue exhibited the highest self‐renewal capacity, cell proliferation, differentiation potential toward various mesenchymal lineage and the highest expression levels of chondrogenic genes and proteins. Transplantation of rat MeSCs derived from day 7 inner meniscus tissue promoted neo‐tissue formation and effectively protected joint surface cartilage in vivo. Our results demonstrated for the first time that rat MeSCs are not necessarily better at earlier developmental stages, and that rat MeSCs derived from day 7 inner meniscus tissue may be a superior cell source for effective meniscus regeneration and articular cartilage protection. This information could make a significant contribution to human meniscus tissue engineering in the future. stem cells translational medicine 2019;8:1318&1329

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<![CDATA[Rat Mesenchymal Stromal Cell Sheets Suppress Renal Fibrosis via Microvascular Protection]]> https://www.researchpad.co/article/Nf83f49b6-6822-469d-98dd-a7eb3ad630c8

Abstract

Renal fibrosis is one of the largest global health care problems, and microvascular (MV) injury is important in the development of progressive fibrosis. Although conventional cell therapy suppresses kidney injury via the role of vasoprotective cytokines, the effects are limited due to low retention of administered cells. We recently described that transplantation of hepatocyte growth factor (HGF)‐transgenic mesothelial cell sheets showed a remarkable cell survival and strong therapeutic effects in a rat renal fibrosis model. Due to the translational hurdles of transgenic cells, we here applied this technique for allogeneic transplantation using rat bone marrow mesenchymal stromal cells (MSCs). MSC sheets were transplanted onto the kidney surface of a rat renal ischemia–reperfusion‐injury model and the effects were compared between those in untreated rats and those receiving intravenous (IV) administration of the cells. We found that donor‐cell survival was superior in the cell sheet group relative to the IV group, and that the cell sheets secreted HGF and vascular endothelial growth factor (VEGF) up to day 14. Transplantation of cell sheets increased the expression of activated HGF/VEGF receptors in the kidney. There was no evidence of migration of transplanted cells into the kidney parenchyma. Additionally, the cell sheets significantly suppressed renal dysfunction, MV injury, and fibrosis as compared with that observed in the untreated and IV groups. Furthermore, we demonstrated that the MSC sheet protected MV density in the whole kidney according to three‐dimensional microcomputed tomography. In conclusion, MSC sheets strongly prevented renal fibrosis via MV protection, suggesting that this strategy represents a potential novel therapy for various kidney diseases. stem cells translational medicine 2019;8:1330&1341

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<![CDATA[Cell Mass Increase Associated with Formation of Glucose‐Controlling β‐Cell Mass in Device‐Encapsulated Implants of hiPS‐Derived Pancreatic Endoderm]]> https://www.researchpad.co/article/Ncb36e1ff-f0a6-46ad-8a8b-3afe4da2026d

Abstract

Device‐encapsulated human stem cell‐derived pancreatic endoderm (PE) can generate functional β‐cell implants in the subcutis of mice, which has led to the start of clinical studies in type 1 diabetes. Assessment of the formed functional β‐cell mass (FBM) and its correlation with in vivo metabolic markers can guide clinical translation. We recently reported ex vivo characteristics of device‐encapsulated human embryonic stem cell‐derived (hES)‐PE implants in mice that had established a metabolically adequate FBM during 50‐week follow‐up. Cell suspensions from retrieved implants indicated a correlation with the number of formed β cells and their maturation to a functional state comparable to human pancreatic β cells. Variability in metabolic outcome was attributed to differences in number of PE‐generated β cells. This variability hinders studies on processes involved in FBM‐formation. This study reports modifications that reduce variability. It is undertaken with device‐encapsulated human induced pluripotent stem cell‐derived‐PE subcutaneously implanted in mice. Cell mass of each cell type was determined on intact tissue inside the device to obtain more precise data than following isolation and dispersion. Implants in a preformed pouch generated a glucose‐controlling β‐cell mass within 20 weeks in over 60% of recipients versus less than 20% in the absence of a pouch, whether the same or threefold higher cell dose had been inserted. In situ analysis of implants indicated a role for pancreatic progenitor cell expansion and endocrine differentiation in achieving the size of β‐ and α‐cell mass that correlated with in vivo markers of metabolic control. stem cells translational medicine 2019;8:1296&1305

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<![CDATA[Cell‐Based Therapies for Alveolar Bone and Periodontal Regeneration: Concise Review]]> https://www.researchpad.co/article/N6086f8aa-2549-4c04-8728-65b31b133a97

Abstract

Current regenerative strategies for alveolar bone and periodontal tissues are effective and well adopted. These are mainly based on the use of a combination of synthetic/natural scaffolds and bioactive agents, obviating the incorporation of cells. However, there are some inherent limitations associated with traditional techniques, and we hypothesized that the use of cell‐based therapies as part of comprehensive regenerative protocols may help overcome these hurdles to enhance clinical outcomes. We conducted a systematic review of human controlled clinical trials investigating the clinical and/or histological effect of the use of cell‐based therapies for alveolar bone and periodontal regeneration and explored the translational potential of the different cell‐based strategies identified in the included trials. A total of 16 studies (11 randomized controlled trials, 5 controlled clinical trials) were included for data synthesis and qualitative analysis with meta‐analyses performed when appropriate. The results suggest a clinical benefit from the use of cell therapy. Improved outcomes were shown for alveolar ridge preservation, lateral ridge augmentation, and periodontal regeneration. However, there was insufficient evidence to identify best‐performing treatment modalities amongst the different cell‐based techniques. In light of the clinical and histological outcomes, we identify extraction socket and challenging lateral and vertical bone defects requiring bone block grafts as strong candidates for the adjuvant application of mesenchymal stem cells. Given the complexity, invasiveness, and costs associated with techniques that include “substantial manipulation” of tissues and cells, their additional clinical benefit when compared with “minimal manipulation” must be elucidated in future trials. stem cells translational medicine 2019;8:1286&1295

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<![CDATA[A mathematical model of cartilage regeneration after chondrocyte and stem cell implantation – I: the effects of growth factors]]> https://www.researchpad.co/article/5ca25fbad5eed0c4846d8269

Autologous chondrocyte implantation is a cell-based therapy for treating chondral defects. The procedure begins by inserting chondrocytes into the defect region. The chondrocytes initiate healing by proliferating and depositing extracellular matrix, which allows them to migrate into the defect until it is completely filled with new cartilage. Mesenchymal stem cells can be used instead of chondrocytes with similar long-term results. The main differences are at early times since mesenchymal stem cells must first differentiate into chondrocytes before cartilage is formed. To better understand this repair process, we present a mathematical model of cartilage regeneration after cell therapy. We extend our previous work to include the cell–cell interaction between mesenchymal stem cells and chondrocytes via growth factors. Our results show that matrix formation is enhanced at early times in the presence of growth factors. This study reinforces the importance of mesenchymal stem cell and chondrocyte interaction in the cartilage healing process as hypothesised in experimental studies.

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<![CDATA[The Effects of Platelet‐Derived Growth Factor‐BB on Human Dental Pulp Stem Cells Mediated Dentin‐Pulp Complex Regeneration]]> https://www.researchpad.co/article/5b45d61b463d7e54c1d63b08

Abstract

Dentin‐pulp complex regeneration is a promising alternative treatment for the irreversible pulpitis caused by tooth trauma or dental caries. This process mainly relies on the recruitment of endogenous or the transplanted dental pulp stem cells (DPSCs) to guide dentin‐pulp tissue formation. Platelet‐derived growth factor (PDGF), a well‐known potent mitogenic, angiogenic, and chemoattractive agent, has been widely used in tissue regeneration. However, the mechanisms underlying the therapeutic effects of PDGF on dentin‐pulp complex regeneration are still unclear. In this study, we tested the effect of PDGF‐BB on dentin‐pulp tissue regeneration by establishing PDGF‐BB gene‐modified human dental pulp stem cells (hDPSCs) using a lentivirus. Our results showed that PDGF‐BB can significantly enhance hDPSC proliferation and odontoblastic differentiation. Furthermore, PDGF‐BB and vascular endothelial growth factor (VEGF) secreted by hDPSCs enhanced angiogenesis. The chemoattractive effect of PDGF‐BB on hDPSCs was also confirmed using a Transwell chemotactic migration model. We further determined that PDGF‐BB facilitates hDPSCs migration via the activation of the phosphatidylinositol 3 kinase (PI3K)/Akt signaling pathway. In vivo, CM‐DiI‐labeled hDPSCs were injected subcutaneously into mice, and our results showed that more labeled cells were recruited to the sites implanted with calcium phosphate cement scaffolds containing PDGF‐BB gene‐modified hDPSCs. Finally, the tissue‐engineered complexes were implanted subcutaneously in mice for 12 weeks, the Lenti‐PDGF group generated more dentin‐like mineralized tissue which showed positive staining for the DSPP protein, similar to tooth dentin tissue, and was surrounded by highly vascularized dental pulp‐like connective tissue. Taken together, our data demonstrated that the PDGF‐BB possesses a powerful function in prompting stem cell‐based dentin‐pulp tissue regeneration. Stem Cells Translational Medicine 2017;6:2126–2134

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