Fazekasova H.,King's College London |
Lechler R.,King's College London |
Langford K.,Smith and Nephew Research Center |
Lombardi G.,King's College London
Journal of Tissue Engineering and Regenerative Medicine | Year: 2011
Over the past few years, mesenchymal stem cells (MSCs) have become of increasing interest for use in the field of regenerative medicine. To date, bone marrow (BM) has been the main source of MSCs (BM-MSCs) for both experimental and clinical studies. However, the use of MSCs derived from BM can be problematic, due to the low number of MSCs found in bone marrow aspirates and the invasive procedure associated with obtaining them. We aimed to develop a method of obtaining high numbers of purified MSCs from placental tissue with minimal expansion and to characterize their phenotype and function relative to BM-MSCs. We show here that placenta-derived MSCs (PD-MSCs) can be isolated with high numbers from whole placental tissue. However, PD-MSCs isolated from whole tissue were often found to be a mixed population of both maternal and neonatal cells. The immunological properties of PD-MSCs and BM-MSCs were compared. PD-MSCs were found to express lower levels of HLA class I and higher levels of PDL-1 and CD1a, compared to BM-MSCs. HLA-DR became upregulated in PD-MSCs following treatment with IFNγ, whereas BM-MSCs expressed constitutively low levels of HLA-DR. Whilst untreated or IFNγ-treated BM-MSCs were incapable of stimulating T cells, we observed a small T cell proliferation in response to the highest concentration of PD-MSCs when treated with IFNγ. It was noted that BM-MSCs were more immunomodulatory than PD-MSCs in this study. We therefore suggest that BM-MSCs may be better candidates for use in commercial regenerative or transplantation medicine. © 2010 John Wiley & Sons, Ltd.
Boettger M.K.,Friedrich - Schiller University of Jena |
Boettger M.K.,Bayer AG |
Kummel D.,Friedrich - Schiller University of Jena |
Harrison A.,Smith and Nephew Research Center |
Schaible H.-G.,Friedrich - Schiller University of Jena
Arthritis Research and Therapy | Year: 2011
Introduction: Clinical trials provided controversial results on whether the injection of hyaluronan preparations into osteoarthritic joints reduces pain. Problems of clinical studies may be the substantial placebo effects of intra-articular injections, different severity and rate of progression of the disease and others. We hypothesize that the use of preclinical pain models may help to clarify whether a certain hyaluronan exerts antinociceptive effects upon intra-articular injection. In the present study we tested in the bradykinin/prostaglandin E2(PGE2) model primarily the putative antinociceptive effect of stabilized hyaluronic acid from a non animal source (NASHA), a stabilized hyaluronic acid based gel for intra-articular treatment of OA. We established a dose-response relationship for NASHA and we compared NASHA to other hyaluronans with different formulations that are in clinical use.Methods: To induce transient joint pain episodes bradykinin and PGE2were repetitively administered intra-articularly and unilaterally into rat knee joints during short anaesthesia. After establishment of the predrug nociceptive responses, a single intra-articular injection of saline or NASHA at different concentrations was administered and pain responses to further bradykinin/PGE2injections were monitored up to 56 days after NASHA. Furthermore, the obtained effective dose was compared to clinically defined concentrations of Hylan GF20 and sodium hyaluronate. The primary outcome measures were primary mechanical hyperalgesia at the knee joint and pain-induced weight bearing.Results: On day 1 after injection, all tested hyaluronan preparations showed an antinociceptive effect >50% compared to saline. Single injections of higher doses of NASHA (50, 75 and 100 μl) were antinociceptive up to 56 days. When injection volumes in rat knee joints were adapted to clinical injection volumes in humans, the antinociceptive effects of the cross-linked NASHA and Hylan GF20 had a longer duration than that of the non cross-linked sodium hyaluronate (with a slightly better effect of NASHA than Hylan GF20).Conclusions: In the bradykinin/PGE2model of joint pain a single injection of all hyaluronan preparations provided significant antinociceptive effects compared to saline. It appeared that the duration of the antinociceptive effect of the cross-linked hyaluronan preparations NASHA and Hylan GF20 was more prolonged. In addition, the gel beads structure allowing only a slow release of hyaluronic acid (NASHA) may even enhance this prolonged antinociceptive effect. © 2011 Boettger et al.; licensee BioMed Central Ltd.
Montes De Oca H.,University of Leeds |
Farrar D.F.,Smith and Nephew Research Center |
Ward I.M.,University of Leeds
Acta Biomaterialia | Year: 2011
Highly oriented poly(glycolic acid) (PGA) fibres with an initial tensile strength of 1.1 GPa and different lamellar morphologies were prepared and studied during degradation in aqueous media at 37 °C. A combination of small- and wide-angle X-ray scattering was used to study the structural changes during degradation and to generate two structural models of highly oriented PGA fibres with different lamellar morphologies. It is shown that as a result of crystallisation during degradation PGA crystals grow preferentially along the (1 1 0) and (0 2 0) directions of the crystal lattice or perpendicular to the orientation direction of the fibres. 1H nuclear magnetic resonance measurements revealed three phases within the fibres with different relaxation times: (1) a mobile amorphous phase with a short relaxation time; (2) a semi-rigid phase with an intermediate relaxation time; (3) a rigid crystalline phase with a longer relaxation time. It is shown that the mobile amorphous phase degrades very rapidly and that it plays only a small role in the tensile mechanical behaviour of the fibres during degradation. It is shown that semi-rigid chains connecting crystalline domains are responsible for transferring the stress between crystalline domains and carrying the tensile deformation. It is proposed that once these tie molecules degrade considerably the oriented fibres very rapidly lose their strength retention. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Frith J.E.,University of York |
Thomson B.,Smith and Nephew Research Center |
Genever P.G.,University of York
Tissue Engineering - Part C: Methods | Year: 2010
Mesenchymal stem cells (MSCs) are capable of self-renewal and differentiation along the osteogenic, chondrogenic, and adipogenic lineages and have potential applications in a range of therapies. MSCs can be cultured as monolayers on tissue culture plastic, but there are indications that they lose cell-specific properties with time in vitro and so poorly reflect in vivo MSC behavior. We developed dynamic three-dimensional (3D) techniques for in vitro MSC culture using spinner flasks and a rotating wall vessel bioreactor. We characterized the two methods for dynamic 3D MSC culture and compared the properties of these cultures with monolayer MSCs. Our results showed that under optimal conditions, MSCs form compact cellular spheroids and remain viable in dynamic 3D culture. We demonstrated altered cell size and surface antigen expression together with enhanced osteogenic and adipogenic differentiation potential in MSCs from dynamic 3D conditions. By microarray analysis of monolayer and spinner flask MSCs, we identified many differences in gene expression, including those confirming widespread changes to the cellular architecture and extracellular matrix. The upregulation of interleukin 24 in dynamic 3D cultures was shown to selectively impair the viability of prostate cancer cells cultured in medium conditioned by dynamic 3D MSCs. Overall, this work suggests a novel therapeutic application for dynamic 3D MSCs and demonstrates that these methods are a viable alternative to monolayer techniques and may prove beneficial for retaining MSC properties in vitro. © 2010 Mary Ann Liebert, Inc.
Saleh F.A.,University of York |
Whyte M.,Smith and Nephew Research Center |
Genever P.G.,University of York
European Cells and Materials | Year: 2011
An increasing body of data suggest that mesenchymal stem cells (MSCs) reside in a perivascular niche. To more closely mimic this in vivo microenvironment and for better understanding of its complexity, and the factors that regulate the MSC activity, human umbilical vein endothelial cells (HUVECs) were co-cultured with human bone marrow MSCs - using a novel three-dimensional (3D) spheroid co-culture system. Using confocal microscopy of fluorescently labelled cells, we observed HUVECs and MSCs to self-assemble and form organised structures with segregated cell-type partitioning. Under osteogenic conditions, the rate and extent of differentiation in MSC/ HUVEC spheroids was significantly elevated compared to 3D co-cultures of MSCs and human dermal fibroblast controls as shown by alkaline phosphatase staining. Conversely, HUVECs inhibited adipogenic differentiation and the proliferation of MSCs in 3D co-cultures indicating that HUVECs suppressed MSC cycling and selectively promoted osteogenic differentiation in 3D. We have also shown that HUVECs enhanced activation of endogenous Wnt signalling and bone morphogenetic protein (BMP) signalling as shown by increased levels of active nuclear β-catenin and pSmad 1/5/8 immunopositivity respectively. These data suggest strongly that endothelial cells regulate the MSC activity in simulated in vivo conditions, by maintaining quiescence and facilitating niche exit via osteogenic differentiation following appropriate cues. Our findings also underline the importance of 3D heterotypic cell-cell interactions in the regulation of MSC behaviour, suggesting that multicellular cocktails and/or 3D-based delivery strategies may be beneficial for bone repair.
Saleh F.A.,University of York |
Whyte M.,Smith and Nephew Research Center |
Ashton P.,University of York |
Genever P.G.,University of York
Stem Cells and Development | Year: 2011
Emerging data suggest that mesenchymal stem cells (MSCs) are part of a periendothelial niche, suggesting the existence of heterotypic cell-cell crosstalk between endothelial cells and MSCs that regulate MSCs in their local microenvironment. We determined the effects of paracrine factors secreted by human umbilical vein endothelial cells (HUVECs) on MSC survival, proliferation, and differentiation by using an optimized, serum-free HUVEC-conditioned medium (CM). HUVEC-CM induced a significant increase in the size and number of colony-forming units-fibroblast (CFU-F) and CFU-osteoblast (CFU-O) and stimulated the proliferation of MSCs as determined by 5-bromo-2′- deoxyuridine incorporation, compared with non-CM. We also demonstrated that CM significantly enhanced the osteogenic differentiation of MSCs as shown by alkaline phosphatase enzyme histochemistry and von Kossa staining of mineralized nodules as well as by quantitative reverse transcriptase-polymerase chain reaction analysis of osteogenic markers. In contrast, there was no effect on the adipogenic differentiation of MSCs. Bioinformatic integration of HUVEC and MSC gene expression datasets identified several candidate signaling pathways responsible for mediating these effects, including fibroblast growth factor, Wnt, bone morphogenetic protein, and Notch. These data suggest strongly that endothelial cells secrete a soluble factor (or factors) that stimulates progenitor cell activity and, selectively, the osteogenic differentiation of MSCs that could contribute to niche exit. © 2011, Mary Ann Liebert, Inc.
Ehrenfried L.M.,University of Cambridge |
Farrar D.,Smith and Nephew Research Center |
Cameron R.E.,University of Cambridge
Journal of the Royal Society Interface | Year: 2010
This study investigates the in vitro degradation properties of composites consisting of a porous tricalcium phosphate (TCP) foam filled with degradable poly(DL-lactic acid) (PDLLA) via either in situ polymerization or infiltration. The motivation was to develop a material for bone repair that would be initially mechanically strong and would develop porosity during degradation of one of the components. A thorough analysis of the physical in vitro degradation properties has been conducted and reported by the same authors elsewhere. Synchrotron microcomputer tomography analysis (conducted at ID19, ESRF, Grenoble, France) allowed detailed insights to be gained into the process of the composites' degradation, which was discovered to be strongly influenced by the manufacturing method. The polymer phase of in situ-polymerized TCP-PDLLA degraded as a bulk sample, with faster degradation in the centre of the sample as a whole. In contrast, the polymer phase of infiltrated TCP-PDLLA degraded as individual polymer spheres with faster degradation in the centre of each sphere. 2010 The Royal Society.
Farrar D.,Smith and Nephew Research Center
Advanced Wound Repair Therapies | Year: 2011
Wound repair is an important and growing sector of the medical industry with increasingly sophisticated biomaterials and strategies being developed to treat wounds. Advanced wound repair therapies provides readers with up-to-date information on current and emerging biomaterials and advanced therapies concerned with healing surgical and chronic wounds. Part one provides an introduction to chronic wounds, with chapters covering dysfunctional wound healing, scarring and scarless wound healing and monitoring of wounds. Part two covers biomaterial therapies for chronic wounds, including chapters on functional requirements of wound repair biomaterials, polymeric materials for wound dressings and interfacial phenomena in wound healing. In part three, molecular therapies for chronic wounds are discussed, with chapters on topics such as drug delivery, molecular and gene therapies and antimicrobial dressings. Part four focuses on biologically-derived and cell-based therapies for chronic wounds, including engineered tissues, biologically-derived scaffolds and stem cell therapies for wound repair. Finally, part five covers physical stimulation therapies for chronic wounds, including electrical stimulation, negative pressure therapy and mechanical debriding devices. © 2011 Woodhead Publishing Limited. All rights reserved.
Farrar D.F.,Smith and Nephew Research Center
International Journal of Adhesion and Adhesives | Year: 2012
The idea of being able to glue bone fragments with a suitable biocompatible adhesive remains highly attractive to orthopaedic surgeons. Yet despite decades of research, no suitable system that fully meets all the many requirements for such an adhesive has yet been identified. This article reviews the requirements and challenges of developing a bone adhesive for fracture repair and also the substantial progress that has been made. Developments in bone adhesives can roughly be classified into two groups: synthetic and biologically-derived/ inspired. Early examples of synthetic adhesives include poly(methyl methacrylate) and related polymers, cyanoacrylates and polyurethanes. These materials are characterised by relatively good mechanical properties but often lack the required biocompatibility and biodegradability. More recent adhesive systems based on lactidemethacrylate chemistry therefore attempt to address these issues. Similarly, there is renewed interest in glass ionomer cements and calcium/magnesium phosphate cements. Biological adhesives include fibrin and gelatin-based systems. These have good biocompatibility and biodegradability but lack the cohesive strength to have good adhesion to bone and are used chiefly in soft tissue applications. Newer examples that are looking more promising include adhesives inspired by mussel adhesive proteins and the sandcastle glue of the marine worm Phragmatopoma californica. As well as the challenge to develop the adhesive systems themselves a further need is for greater consistency in the testing of adhesion to bone both in vitro/ex vivo and in vivo. Test methods in the literature are reviewed together with considerations for the design of such tests. © 2011 Elsevier Ltd. All rights reserved.
Plaas A.,Rush University Medical Center |
Li J.,Rush University Medical Center |
Riesco J.,Rush University Medical Center |
Das R.,Rush University Medical Center |
And 2 more authors.
Arthritis Research and Therapy | Year: 2010
Introduction: Intraarticular hyaluronan (HA) is used clinically for symptomatic relief in patients with knee osteoarthritis (OA); however, the mechanism of action is unclear. In this study, we examined the effects of a single injection of HA on joint tissue pathology, mechanical allodynia and gait changes (measured by stride times) in a murine model of OA.Methods: OA was induced in the right knee joint (stifle) of 12-week-old male C57BL/6 mice by transforming growth factor β1 (TGFβ1) injection and treadmill running for 14 days. Gait parameters were quantified by using TreadScan, mechanical allodynia was evaluated with von Frey filaments, and joint pathology was evaluated by scoring of macroscopic images for both cartilage erosion and periarticular fibrosis. HA or saline control was injected 1 day after TGFβ1 injection but before the start of treadmill running.Results: OA development in this model was accompanied by significant (P < 0.01) enhancement of the stance and propulsion times of affected legs. HA injection (but not saline injection) blocked all gait changes and also protected joints from femoral cartilage erosion as well as tibial and femoral tissue fibrosis. Both HA injection and saline injection attenuated acute allodynia, but the HA effect was more pronounced and prolonged than the saline injection.Conclusions: We conclude that videographic gait analysis is an objective, sensitive and reproducible means of monitoring joint pathology in experimental murine OA, since stance time appears to correlate directly with OA severity. A single injection of HA prevents acute and prolonged gait changes and ameliorates the cartilage erosion and periarticular fibrosis normally seen in this model. We speculate that the capacity of HA to prevent cartilage erosion results from its normalization of joint biomechanics and its inhibitory effects on periarticular cells, which are involved in tissue hyperplasia and fibrosis. This effect of exogenous HA appears to mimic the protective effects of ablation of Adamts5 (a disintegrin and metalloproteinase with thrombospondin motifs 5) on experimental murine OA, and we speculate that a common mechanism is involved. © 2011 Plaas et al.; licensee BioMed Central Ltd.