pinecone/core-2020-05-10-deduplication huggingface dataset:
On the use of dexamethasone-loaded liposomes to induce the osteogenic differentiation of human mesenchymal stem cells

Article first published online: 7 Oct. 2013Stem cells have received considerable attention by the scientific community because of their potential for tissue engineering and regenerative medicine. The most frequently used method to promote their differentiation is supplementation of the in vitro culture medium with growth/differentiation factors (GDFs). The limitations of that strategy caused by the short half-life of GDFs limit its efficacy in vivo and consequently its clinical use. Thus, the development of new concepts that enable the bioactivity and bioavailability of GDFs to be protected, both in vitro and in vivo, is very relevant. Nanoparticle-based drug delivery systems can be injected, protect the GDFs and enable spatiotemporal release kinetics to be controlled. Liposomes are well-established nanodelivery devices presenting significant advantages, viz. a high load-carrying capacity, relative safety and easy production, and a versatile nature in terms of possible formulations and surface functionalization. The main objective of the present study was to optimize the formulation of liposomes to encapsulate dexamethasone (Dex). Our results showed that the optimized Dex-loaded liposomes do not have any cytotoxic effect on human bone marrow-derived mesenchymal stem cells (hBMSCs). More importantly, they were able to promote an earlier induction of differentiation of hBMSCs into the osteogenic lineage, as demonstrated by the expression of osteoblastic markers, both phenotypically and genotypically. We concluded that Dex-loaded liposomes represent a viable nanoparticle strategy with enhanced safety and efficacy for tissue engineering and regenerative medicine.The authors thank the Portuguese Foundation for Science and Technology for a PhD grant (No. SFRH/BD/62465/2009, to N. S. Monteiro). This work was partly supported by the FIND and BIND Project (No. NMP4-SL-2009-229292) and the OsteoGraphy Project (No. PTDC/EME-MFE/2008)
Influence of the surface chemistry in the osteogenic activity of silica nano particles

Polyeletrolyte multilayers (PEM) have been extensively studied in the biomedical field, namely as biodegradable systems, biosensors and drug delivery systems [1]. Using PEM films, it is possible to control the early steps in cell adhesion but also processes that occur at a longer time scale, such as cell differentiation and tissue formation. In this work, we study the influence of silica particles concentration, coated with polyelectrolytes, and we evaluate their biological activity (osteogenic differentiation of human bone marrow stem cells - hBMSC) as a function of the nanoparticle’s concentration and surface coating. We chose to execute the polyelectrolyte constructions using poly-L-lysine (PLL), a polycation which is widely used in cell culture to promote cell adhesion to solid substrates [2], and hyaluronic acid (HA), a polyanion, which is known for providing excellent biocompatibility and have been used for ophthalmic surgery, treatment of arthritis, drug delivery, and tissue engineering [3]. In this context, we prepared silica nanoparticles (diameter of ~174nm) and silica particles coated with PLL-HA (diameter of ~200 nm). Further on, we studied the activity of these systems, under different concentration of particles (50µg/mL, 25µg/mL and 12,5µg/mL), towards the osteogenic differentiation of hBMSC. The cell viability, cell proliferation, protein quantification (i.e. ALP, DNA and MTS) and gene expression (evaluated by RT-PCR, i.e. Osteocalcin, Bone Sialoprotein, Runx2, Osteopontin and Osterix) was monitored, during 21 days. Our data indicates the overexpression of some of the osteogenic transcripts (e.g. Bone Sialoprotein, Osteocalcin and Osterix) in the hBMSCs cultured in the presence of SiO2-PLL-HA, under concentrations of 100µg/mL and 50µg/mL, in comparison with non-coated silica nanoparticles
Performance of new gellan gum hydrogels combined with human articular chondrocytes for cartilage regeneration when subcutaneously implanted in nude mice

Gellan gum is a polysaccharide that has been recently proposed by our group for cartilage tissueengineering
applications. It is commonly used in the food and pharmaceutical industry and has
the ability to form stable gels without the use of harsh reagents. Gellan gum can function as a
minimally invasive injectable system, gelling inside the body in situ under physiological conditions
and efficiently adapting to the defect site. In this work, gellan gum hydrogels were combined with
human articular chondrocytes (hACs) and were subcutaneously implanted in nude mice for 4 weeks.
The implants were collected for histological (haematoxylin and eosin and Alcian blue staining),
biochemical [dimethylmethylene blue (GAG) assay], molecular (real-time PCR analyses for collagen
types I, II and X, aggrecan) and immunological analyses (immunolocalization of collagen types I and
II). The results showed a homogeneous cell distribution and the typical round-shaped morphology
of the chondrocytes within the matrix upon implantation. Proteoglycans synthesis was detected by
Alcian blue staining and a statistically significant increase of proteoglycans content was measured
with the GAG assay quantified from 1 to 4 weeks of implantation. Real-time PCR analyses showed a
statistically significant upregulation of collagen type II and aggrecan levels in the same periods. The
immunological assays suggest deposition of collagen type II along with some collagen type I. The
overall data shows that gellan gum hydrogels adequately support the growth and ECM deposition
of human articular chondrocytes when implanted subcutaneously in nude mice.J. T. Oliveira would like to acknowledge the Portuguese Foundation for Science and Technology (FCT) for his grant (SFP,H/BD17135/2004). The authors would like to thank the patients at Hospital de S. Marcos, Braga, Portugal, for the donation of the biological samples and the medical staff for their help and support. The authors would also like to thank the Institute for Health and Life Sciences (ICVS), University of Minho, Braga, Portugal, for allowing the use of their research facilities. This work was carried out under the scope of European NoE EXPERTISSUES (Project No. NMP3-CT-2004-500283) and partially supported by the European Project HIPPOCRATES (No. STRP 505758-1)
Poly(ester-urethane) scaffolds: effect of structure on properties and osteogenic activity of stem cells

The present study aimed to investigate the effect of structure (design and porosity) on the matrix stiffness and osteogenic activity of stem cells cultured on poly(ester-urethane) (PEU) scaffolds. Different three-dimensional (3D) forms of scaffold were prepared from lysine-based PEU using traditional salt-leaching and advanced bioplotting techniques. The resulting scaffolds were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), mercury porosimetry and mechanical testing. The scaffolds had various pore sizes with different designs, and all were thermally stable up to 300â  Â°C.Â In vitrotests, carried out using rat bone marrow stem cells (BMSCs) for bone tissue engineering, demonstrated better viability and higher cell proliferation on bioplotted scaffolds compared to salt-leached ones, most probably due to their larger and interconnected pores and stiffer nature, as shown by higher compressive moduli, which were measured by compression testing. Similarly, SEM, von Kossa staining and EDX analyses indicated higher amounts of calcium deposition on bioplotted scaffolds during cell culture. It was concluded that the design with larger interconnected porosity and stiffness has an effect on the osteogenic activity of the stem cells.This work was supported by the European FP6 NoE EXPERTISSUES project (Grant No. NMP3-500283), the mini-project Fibrocell, TUBITAK (Grant No. TBAG 105 T508 Nanobiomat) and by METU-BAP
Comparative study of NMP-preloaded and dip-loaded membranes for guided bone regeneration of rabbit cranial defects

Guided bone regeneration (GBR) has been utilized for several decades for the healing of cranio-maxillofacial bone defects and, particularly in the dental field, by creating space with a barrier membrane to exclude soft tissue and encourage bone growth in the membrane-protected volume. Although the first membranes were non-resorbable, a new generation of GBR membranes aims to biodegrade and provide bioactivity for better overall results. The Inion GTR™ poly(lactide-co-glycolide) (PLGA) membrane is not only resorbable but also bioactive, since it includes N-methylpyrrolidone (NMP), which has been shown to promote bone regeneration. In this study, the effects of loading different amounts of NMP onto the membrane through chemical vapour deposition or dipping have been explored. In vitro release demonstrated that lower levels of NMP led to lower NMP concentrations and slower release, based on total NMP loaded in the membrane. The dipped membrane released almost all of the NMP within 15 min, leading to a high NMP concentration. For the in vivo studies in rabbits, 6 mm calvarial defects were created and left untreated or covered with an ePTFE membrane or PLGA membranes dipped in, or preloaded with, NMP. Evaluation of the bony regeneration revealed that the barrier membranes improved bony healing and that a decrease in NMP content improved the performance. Overall, we have demonstrated the potential of these PLGA membranes with a more favourable NMP release profile and the significance of exploring the effect of NMP on these PLGA membranes with regard to bone ingrowth
Human periosteal-derived cell expansion in a perfusion bioreactor system: proliferation, differentiation and extracellular matrix formation

Perfusion bioreactor systems have shown to be a valuable tool for the in vitro development of three-dimensional (3D) cell-carrier constructs. Their use for cell expansion, however, has been much less explored. Since maintenance of the initial cell phenotype is essential in this process, it is imperative to obtain insight into the bioreactor-related variables determining cell fate. Therefore, this study investigated the influence of fluid flow-induced shear stress on the proliferation, differentiation and matrix deposition of human periosteal-derived cells in the absence of additional differentiation-inducing stimuli; 120 000 cells were seeded on additive manufactured 3D Ti6Al4V scaffolds and cultured for up to 28 days at different flow rates in the range 0.04-6 ml/min. DNA measurements showed, on average, a three-fold increase in cell content for all perfused conditions in comparison to static controls, whereas the magnitude of the flow rate did not have an influence. Contrast-enhanced nanofocus X-ray computed tomography showed substantial formation of an engineered neotissue in all perfused conditions, resulting in a filling (up to 70%) of the total internal void volume, and no flow rate-dependent differences were observed. The expression of key osteogenic markers, such as RunX2, OCN, OPN and Col1, did not show any significant changes in comparison to static controls after 28 days of culture, with the exception of OSX at high flow rates. We therefore concluded that, in the absence of additional osteogenic stimuli, the investigated perfusion conditions increased cell proliferation but did not significantly enhance osteogenic differentiation, thus allowing for this process to be used for cell expansion. Copyright © 2014 John Wiley & Sons, Ltd.status: publishe
Polymeric nanofibrous substrates stimulate Pluripotent Stem Cells to form three-dimensional multilayered patty-like spheroids in feeder-free culture and maintain their pluripotency

Expansion of pluripotent stem cells in defined media devoid of animal-derived feeder cells to generate multilayered three-dimensional (3D) bulk preparations or spheroids, rather than two-dimensional (2D) monolayers, is advantageous for many regenerative, biological or disease-modelling studies. Here we show that electrospun polymer matrices comprised of nanofibres that mimic the architecture of the natural fibrous extracellular matrix allow for feeder-free expansion of pluripotent human induced pluripotent stem cells (IPSCs) and human embryonic stem cells (HESCs) into multilayered 3D 'patty-like' spheroid structures in defined xeno-free culture medium. The observation that IPSCs and HESCs readily revert to 2D growth in the absence of the synthetic nanofibre membranes suggests that this 3D expansion behaviour is mediated by the physical microenvironment and artificial niche provided by the nanofibres only. Importantly, we could show that such 3D growth as patties maintained the pluripotency of cells as long as they were kept on nanofibres. The generation of complex multilayered 3D structures consisting of only pluripotent cells on biodegradable nanofibre matrices of the desired shape and size will enable both industrial-scale expansion and intricate organ–tissue engineering applications with human pluripotent stem cells, where simultaneous coupling of differentiation pathways of all germ layers from one stem cell source may be required for organ formation.Griffith Health FacultyFull Tex
Materials in particulate form for tissue engineering. 1 Basic concepts

For biomedical applications, materials small in size are growing in importance. In an era where
‘nano’ is the new trend, micro- and nano-materials are in the forefront of developments. Materials in
the particulate form aim to designate systems with a reduced size, such as micro- and nanoparticles.
These systems can be produced starting from a diversity of materials, of which polymers are the
most used. Similarly, a multitude of methods are used to produce particulate systems, and both
materials and methods are critically reviewed here. Among the varied applications that materials
in the particulate form can have, drug delivery systems are probably the most prominent, as these
have been in the forefront of interest for biomedical applications. The basic concepts pertaining
to drug delivery are summarized, and the role of polymers as drug delivery systems conclude this
review
Sustained-release of naproxen sodium from electrospun-aligned PLLA/PCL scaffolds

This is the peer reviewed version of the following article: LUI, Y.S., LEWIS, M.P. and LOO, S.C.J., 2015. Sustained-release of naproxen sodium from electrospun-aligned PLLA/PCL scaffolds. Journal of Tissue Engineering and Regenerative Medicine, which has been published in final form at http://dx.doi.org/10.1002/term.2000. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Spontaneous tendon healing may result in reduced tissue functionality. In view of this, tissue engineering (TE) emerges as a promising approach in promoting proper tendon regeneration. However, unfavourable post-surgical adhesion formations restrict adequate tendon healing through the TE approach. Naproxen sodium (NPS), a non-steroidal anti-inflammatory drug (NSAID), has been demonstrated to prevent adhesions by inhibiting inflammatory response. Therefore, in this work, various factors, i.e. polymer composition (i.e. different poly-l-lactic acid (PLLA) to polycaprolactone (PCL) ratios) and percentage of water (H2O) to hexafluoroisopropanol (HFIP) as co-solvent, were investigated to understand how these can influence the release of NPS from electrospun scaffolds. By adjusting the amount of H2O as the co-solvent, NPS could be released sustainably for as long as two weeks. Scaffold breaking strength was also enhanced with the addition of H2O as the co-solvent. This NPS-loaded scaffold showed no significant cytotoxicity, and L929 murine fibroblasts cultured on the scaffolds were able to proliferate and align along the fiber orientation. These scaffolds with desirable tendon TE characteristics would be promising candidates in achieving better tendon regeneration in vivo
Biodistribution and preliminary therapeutic potential of CMCht/PAMAM dendrimer nanoparticles administration in rats

The development of drug delivery systems (DDS) for targeted intracellular
delivery of therapeutic agents has been attracting great deal of
attention. In traumatic central nervous system conditions, where therapies
have been revealing to be highly inneficient and non-specific, these
targeted DDS could be highly beneficial. We have previously shown in
vitro studies where the carboxymethylchitosan (CMCht)/ poly(amidoamine)
(PAMAM) nanoparticles (NPs) were able to be uptaken by different
cell types (neurons and glial cells), while not evidencing any
cytotoxicity. In the present study, in vivo biodistribution of the CMCht/
PAMAM NPs was investigated. Following intravenous injection in adult
male Wistar rats, the NPs showed to be stable in circulation and able to
be internalized by cells from different tissues (e.g., brain, liver, kidney
and lung). Afterwards, methylprednisolone (MP)-loaded fluorescentlylabelled
NPs were administered in the cerebrospinal fluid of the cisterna
magna of adult male Wistar rats. Upon the intracisternal injection,
NPs were detected throughout the cortical and parenchimal areas
of the brain, namely in the prefrontal cortex, hippocampus and periventricular
areas after 24 h. More recently, ongoing studies are focusing on the therapeutic value of these methylprednisolone-loaded NPs administered following a spinal cord lesion in rats. Significant differences in the BBB locomotory test were found in MP-NPs treated rats 1 month after injury
In vitro chondrogenic commitment of human Wharton's jelly stem cells by co-culture with human articular chondrocytes.

Wharton's jelly stem cells (WJSCs) are a potential source of transplantable stem cells in cartilage-regenerative strategies, due to their highly proliferative and multilineage differentiation capacity. We hypothesized that a non-direct co-culture system with human articular chondrocytes (hACs) could enhance the potential chondrogenic phenotype of hWJSCs during the expansion phase compared to those expanded in monoculture conditions. Primary hWJSCs were cultured in the bottom of a multiwell plate separated by a porous transwell membrane insert seeded with hACs. No statistically significant differences in hWJSCs duplication number were observed under either of the culture conditions during the expansion phase. hWJSCs under co-culture conditions show upregulations of collagen type I and II, COMP, TGFÎ²1 and aggrecan, as well as of the main cartilage transcription factor, SOX9, when compared to those cultured in the absence of chondrocytes. Chondrogenic differentiation of hWJSCs, previously expanded in co-culture and monoculture conditions, was evaluated for each cellular passage using the micromass culture model. Cells expanded in co-culture showed higher accumulation of glycosaminoglycans (GAGs) compared to cells in monoculture, and immunohistochemistry for localization of collagen type I revealed a strong detection signal when hWJSCs were expanded under monoculture conditions. In contrast, type II collagen was detected when cells were expanded under co-culture conditions, where numerous round-shaped cell clusters were observed. Using a micromass differentiation model, hWJSCs, previously exposed to soluble factors secreted by hACs, were able to express higher levels of chondrogenic genes with deposition of cartilage extracellular matrix components, suggesting their use as an alternative cell source for treating degenerated cartilage.European Union-funded Network of  Excellence’EXPERTISSUES’(Grant  No.  NMP3-CT-2004-500283)
Posterior talar process as a suitable cell source for treatment of cartilage and osteochondral defects of the talus

Osteochondral defects of the ankle are common lesions affecting the talar cartilage and subchondral bone. Current treatments include cell-based therapies but are frequently associated with donor-site morbidity. Our objective is to characterize the posterior process of the talus (SP) and the os trigonum (OT) tissues and investigate its potential as a new source of viable cells for application in tissue engineering and regenerative medicine.SP and OT tissues obtained from six patients were characterized by micro-computed tomography, and histological, histomorphometric and immunohistochemical analyses. Isolated cells proliferation and viability were evaluated by MTS assay, DNA quantification and Live/Dead staining. The TUNEL assay was performed to evaluate cell death by apoptosis. Moreover, the production of extracellular matrix was evaluated by toluidine blue staining, whereas cells phenotype was investigated by flow cytometry. Ankle explants characterization showed the presence of a cartilage tissue layer in both SP and OT tissues, which represent, at least 20% in average of the explant. The presence of type II collagen was detected in the extracellular matrix. Isolated cells presented a round morphology typical of chondrocytes. In in vitro studies, cells were viable and proliferating up to 21 days of culturing. No signs of apoptosis were detected. Flow cytometry analysis revealed that isolated cells maintained the expression of several chondrocytic markers during culturing. The results indicate that the SP and OT tissues are a reliable source of viable chondrocytes, which can find promising applications in ACI/MACI strategies with minimal concerns regarding donor zone complications.Portuguese Foundation for Science and Technology (FCT) through the project OsteoCart (Grant No. PTDC/CTM-BPC/115977/2009),   Fundación MAPFRE (Ayudas a la Investigación Ignacio H. de Larramendi, Prevención, Salud y Medio Ambiente, Spain) under the project 'Preventing the progression of the knee osteoarthritis: advanced therapies combining injectable hydrogels, autologous stem cells and PRP' (Grant No. BIL/13/SA/235). This study was also carried out with the support of Fundo Europeu de Desenvolvimento Regional (FEDER) through Programa Operacional do Norte through the project Articulate (Grant No. 23189