Gundula Schulze-tanzil | Paracelsus Medical University Nuernberg (original) (raw)

Papers by Gundula Schulze-tanzil

Macromolecular bioscience, Jan 11, 2016

A stable polymeric network that mimics the highly polyanionic extracellular cartilage matrix stil... more A stable polymeric network that mimics the highly polyanionic extracellular cartilage matrix still remains a great challenge. The main aim of this study is to present the synthesis of dendritic polyglycerol sulfate (dPGS)-based in situ forming hydrogels using strain promoted azide-alkyne cycloaddition reactions. A real time rheological study has been used to characterize the hydrogel properties. The viability of encapsulated human chondrocytes in the different hydrogels are monitored using live-dead staining. Furthermore, type I and II collagen gene have been analyzed. Hydrogels with elastic moduli ranging from 1 to 5 kPa have been prepared by varying the dPGS amount. The chondrocyte viability in dPGS hydrogels is found to be higher than in pure PEG and alginate-based hydrogels after 21 d. The higher cell viability in the dPGS engineered hydrogels can be explained by the fact that dPGS can interact with different proteins responsible for cell growth and proliferation.

BMC Musculoskeletal Disorders, 2015

Anti-inflammatory nanoparticular compounds could represent a strategy to diminish osteoarthritis ... more Anti-inflammatory nanoparticular compounds could represent a strategy to diminish osteoarthritis (OA) progression. The present study was undertaken to prove the uptake of nanoparticular dendritic polyglycerol sulfates (dPGS) by rat-derived articular chondrocytes and to answer the question of whether dPGS could modulate knee joint cartilage degradation in a rat OA model and whether complications could arise. dPGS uptake and cytotoxicity was assessed in cultured primary rat-derived articular chondrocytes. Subsequently, OA was induced in the right knee joints of 12 male Wistar rats by medial collateral ligament and meniscus transection. Unoperated left knees remained as controls. Six weeks post surgery six rats were either treated daily (14 days) with 30 mg/kg dPGS (s.c.) or a similar volume of physiological saline. Animals were analyzed clinically for gait alterations. Explanted knee joints were studied histologically using OA scores according to Mankin (1971), Glasson et al., (2010) and the synovitis score according to Krenn et al., (2006). Liver, spleen and kidneys were analyzed for degenerative changes due to dPGS accumulation. dPGS was taken up after 2 hours by the chondrocytes. Whereas no significant clinical signs of OA could be detected, at the histological level, all operated rat knee joints revealed features of OA in the medial compartment. The values produced by both OA score systems were lower in rats treated with dPGS compared with saline-treated animals. Synovitis score did not significantly differ between the groups. The analyzed organs revealed no degenerative changes. dPGS presented overall cyto- and biocompatibility, no accumulation in metabolizing organs and chondroprotective properties in the osteoarthritic knee joint.

Histology and histopathology

The urokinase-type plasminogen activator receptor (uPAR) plays a critical role in cartilage degra... more The urokinase-type plasminogen activator receptor (uPAR) plays a critical role in cartilage degradation during osteoarthritis as it regulates pericellular proteolysis mediated by serine proteinases. Another important family of proteinases responsible for ECM destruction in arthritis are the matrix metalloproteinases (MMPs). MMPs are regulated by IL-1ß, a cytokine that plays a pivotal role in pathogenesis of osteoarthritis. This study was undertaken to address two questions: 1. Is uPAR-expression regulated by proinflammatory cytokines such as IL-1ß? 2. Does a functional co-localization exist between uPAR and MMPs?

Sensitivity to biomechanical signals and adaptive responses to such stimuli are fundamental prope... more Sensitivity to biomechanical signals and adaptive responses to such stimuli are fundamental properties of articular cartilage. Chondrocytes are specialized cells that utilize mechanical signals to synthesize a mechanically unique extracellular matrix capable of withstanding high loads and shear stresses. Chondrocytes undergo changes in shape and volume when load induces matrix deformation. Changes in hydrostatic pressure, ionic and osmotic composition, interstitial fluid and streaming potentials are sensed by chondrocytes. Responses to these stimuli alter gene expression, matrix composition and biomechanical competence. In this article we focus on the role of mechanosensitive ion channels, !1-integrins and mitogen-activated protein (MAP) kinase kinase pathways in chondrocyte mechanotransduction.

Journal of gravitational physiology: a journal of the International Society for Gravitational Physiology

Weightlessness influences the human immune and hormone system, reduces bone mass, leads to muscle... more Weightlessness influences the human immune and hormone system, reduces bone mass, leads to muscle atrophy and cardiac atrophy. Effects on control mechanisms for proliferation, programmed cell death and differentiation are well documented. The principal aim of this study was to investigate changes of the cytoskeleton in thyroid cells cultured in vector-averaged gravity under clinostat rotation. After 12 hours the formation of multicellular spheroids started. An increase of extracellular matrix proteins and beta 1-integrin was observed. Laser scanning confocal microscopy of ML-1 follicular thyroid carcinoma cells and normal thyroid HTU-5 cells immunostained with anti-cytokeratin to demonstrate these intermediate filaments revealed that cytokeratin filaments extended from centers, were thickened, coalesced and shortened as compared to control cells. Moreover, vimentin was highly disorganized. The vimentin network formed a coiled aggregate closely associated with the nucleus. Western blot analyses of talin, alpha- and beta-tubulin showed a clear increase of these proteins in cells cultured under simulated 0 g. Our data suggest that the effects of microgravity on cultured human thyroid cells are accompanied by noticeable functional cellular changes. Future studies to clarify the pathway that regulate the observed integrin activation and the mechanisms by which they function have to be performed.

Histology and histopathology

The limited ability of articular cartilage to recover from injury, remains an unsolved clinical c... more The limited ability of articular cartilage to recover from injury, remains an unsolved clinical challenge in orthopaedic surgery. Persistent injury of the articular surface can lead to the development of posttraumatic osteoarthritis. The local inflammatory response contributes to the pathogenesis of osteoarthritis by inducing chondrocyte apoptosis and the de-regulation of chondrocyte matrix remodelling. The role of the complement system in contributing to secondary inflammation-mediated cartilage degradation represents a newer field of investigation. The purpose of this review article is to summarize the known complement-mediated actions in cartilage homeostasis and injury. This article focuses on the known effects of complement on secondary chondrocyte apoptosis, and the interplay of the complement system with pro-inflammatory cytokines. Pharmacological therapies related to complement inhibition will be discussed as they potentially represent a new avenue for attenuating the effect of the complement system on cartilage repair.

Inflammation research : official journal of the European Histamine Research Society ... [et al.], Jan 9, 2015

Inflammatory processes driven by cytokines play a crucial role during osteoarthritis (OA) progres... more Inflammatory processes driven by cytokines play a crucial role during osteoarthritis (OA) progression. Dendritic polyglycerol sulfate (dPGS) was analyzed in vitro for its effects on articular chondrocytes, cartilage and cytokines involved in the OA process. The metabolic activity of cultured human articular chondrocytes stimulated for 24 h with dPGS (10(-3)-10(-6) mol/L) was monitored using AlamarBlue(®) assay. The dPGS uptake was studied using fluorescence labeled nanoparticles. Further, chondrocytes were either treated with 10(-6) M dPGS, TNFα (10 ng/mL) alone or with a combination of both. The influence on extracellular matrix components, pro- and anti-inflammatory cytokines, matrix metalloproteinase (MMP)1 and the anaphylatoxin receptor C3aR was analyzed by RTD-PCR, flow cytometry and ELISA. Even at higher dosages (10(-3) mol/L), dPGS did not influence chondrocytes viability. Uptake of dPGS was successfully monitored in human articular chondrocytes and synovial fibroblasts, pene...

Histology and histopathology

Tissue microarrays (TMAs) are an ordered array of tissue cores on a glass slide. They permit immu... more Tissue microarrays (TMAs) are an ordered array of tissue cores on a glass slide. They permit immunohistochemical analysis of numerous tissue sections under identical experimental conditions. The arrays can contain samples of every organ in the human body, or a wide variety of common tumors and obscure clinical cases alongside normal controls. The arrays can also contain pellets of cultured tumor cell lines. These arrays may be used like any histological section for immunohistochemistry and in situ hybridization to detect protein and gene expression. This new technology will allow investigators to analyze numerous biomarkers over essentially identical samples, develop novel prognostic markers and validate potential drug targets. The ability to combine TMA technology with DNA microarrays and proteomics makes it a very attractive tool for analysis of gene expression in clinically stratified tumor specimens and relate expression of each particular protein with clinical outcome. Public d...

Histology and histopathology, 2001

Beta1-integrins were found in the cartilage matrix, suggesting their implication in the assembly ... more Beta1-integrins were found in the cartilage matrix, suggesting their implication in the assembly of its architectural scaffold, but the mechanism for this event is not yet clear. Matrix metalloproteinases (MMPs) may be involved in an integrin-shedding mechanism and matrix beta1-integrins may act to alter MMP activity. To begin to address this question, this study was designed to determine whether beta1-integrins and MMPs are colocalized in the chondrocytes or in the extracellular matrix of cartilage. We investigated high-density cultures of limb buds of 12-day-old mouse embryos by double immunofluorescence, immunoelectron microscopy and by coimmunoprecipitation assays in order to examine the localization of beta1-integrins and matrix metalloproteinases (MMP-1, MMP-3 and MMP-9) in cartilage. It was found, that all investigated MMPs and beta1-integrins were specifically co-localized in high-density cartilage cultures. Immunogold and immunofluorescence labelling of both beta1-integrins...

Histology and histopathology, 2006

Cultivation of phenotypically stable auricular chondrocytes will have applications in autologous ... more Cultivation of phenotypically stable auricular chondrocytes will have applications in autologous chondrocyte transplantation and reconstructive surgery of cartilage. Chondrocytes grown in monolayer culture rapidly dedifferentiate assuming a fibroblast-like morphology and lose their cartilage-specific pattern of gene expression. Three-dimensional high-density culture models mimic more closely the in vivo conditions of cartilage. Therefore, this study was undertaken to test whether the high-density cultures might serve as a suitable model system to acquire phenotypically and functionally differentiated auricular chondrocytes from porcine cartilage. Freshly isolated porcine auricular chondrocytes were cultured for 7 passages in monolayer culture. From each passage (passage 0 and 1-7) cells were introduced to high-density cultures and examined by transmission electron microscopy. Western blotting was used to analyse the expression of cartilage-specific markers, such as collagen type II ...

Muscles, ligaments and tendons journal, 2011

Leukocyte derived pro-inflammatory mediators could be involved in tendon healing and scar formati... more Leukocyte derived pro-inflammatory mediators could be involved in tendon healing and scar formation. Hence, the effect of autologous leukocytes (PBMCs, peripheral blood mononuclear cells and neutrophils) on primary rabbit Achilles tenocytes gene expression was tested in insert assisted co-cultures. Subsequently, tenocytes gene expression of extra-cellular matrix (ECM) components (type I collagen, decorin, fibronectin), the cell-ECM receptor β1-integrin, the angiogenic factor myodulin, ECM degrading matrix-metalloproteinase (MMP)1 and pro-inflammatory cytokines (interleukin [IL]-1β, tumour necrosis factor [TNFα] and IL-6) was analysed. The only significant effect of leukocytes on tenocytes ECM genes expression was a suppression of type I collagen by neutrophils combined with TNFα stimulation. The same effect could be observed analysing the β1-integrin and myodulin gene expression. However, PBMCs up-regulated significantly cytokine and MMP1 gene expression in tenocytes. These in vitro...

European Archives of Oto-Rhino-Laryngology, 2014

Nasal sprays were introduced several years ago to support the treatment of allergic rhinitis. The... more Nasal sprays were introduced several years ago to support the treatment of allergic rhinitis. These sprays may come in direct contact with directly exposed nasoseptal cartilage (e.g. is case of nasoseptal perforation). To date, no studies investigated the effects of nasal sprays on cartilage tissues and cells. Therefore, our aim was to analyze the influence of two different nasal spray types (thixotropic and liposomal) on the vitality of nasoseptal chondrocytes. Human chondrocytes were isolated from surgically dissected tissues. Alternatively, nasal septa (porcine and human) tissue explants were used. The cell or explant cultures were treated with nasal sprays for 4-24 h. As a read-out, cell vitality and gene and protein expression profiles of type I and II collagen, SOX 9 and matrix metalloproteinase MMP-1 were compared to the untreated controls by means of real-time RT-PCR and immunostaining. Using the liposomal, but not thixotropic nasal spray in an explant or chondrocyte in vitro culture led to increased cell death, as compared to the untreated controls. A trend towards suppression of type II collagen and SOX 9 on protein level was found in cultures exposed to liposomal nasal spray, as compared to the controls. The thixotropic nasal spray has not affected the nasoseptal chondrocytes. Further studies with the use of viable nasoseptal cartilage explants and particularly using an in vivo animal model of exposed nasoseptal cartilage are necessary to clear the effect of liposomal spray on chondrocytes.

Bone and Tissue Regeneration Insights, 2014

Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology, 2004

Weightlessness influences the human immune and hormone system, reduces bone mass, leads to muscle... more Weightlessness influences the human immune and hormone system, reduces bone mass, leads to muscle atrophy and cardiac atrophy. Effects on control mechanisms for proliferation, programmed cell death and differentiation are well documented. The principal aim of this study was to investigate changes of the cytoskeleton in thyroid cells cultured in vector-averaged gravity under clinostat rotation. After 12 hours the formation of multicellular spheroids started. An increase of extracellular matrix proteins and beta 1-integrin was observed. Laser scanning confocal microscopy of ML-1 follicular thyroid carcinoma cells and normal thyroid HTU-5 cells immunostained with anti-cytokeratin to demonstrate these intermediate filaments revealed that cytokeratin filaments extended from centers, were thickened, coalesced and shortened as compared to control cells. Moreover, vimentin was highly disorganized. The vimentin network formed a coiled aggregate closely associated with the nucleus. Western bl...

Cell and Tissue Banking, 2014

ABSTRACT Adult mesenchymal stem cells (MSCs) are a promising cell source in tissue engineering du... more ABSTRACT Adult mesenchymal stem cells (MSCs) are a promising cell source in tissue engineering due to their availability, ease of isolation and high proliferative activity. This study was undertaken to investigate whether immortalised human MSC are able to undergo chondrogenic differentiation when cultured in alginate or in resorbable scaffolds. We directly compared chondrogenesis MSCs with that of human nasoseptal chondrocytes. Two previously established human stem cell lines L87/4 and V54-2 immortalised using the SV40 large T-antigen were either cultured in alginate or in polyglycolic acid/poly-L-lactic acid (PGA/PLLA) (90/10) copolymer scaffolds. TGF-β1 was added for induction of chondrogenesis. Human nasoseptal chondrocytes and human fibroblasts were used as controls. Cultures were analysed for sulfated glycosaminoglycans (alcian blue staining) and for the presence of collagen type I, II and X (immunolabelling). SV40 large T-antigen immortalised human MSCs have the potential to undergo chondrogenic differentiation: After 21 days, cartilage-specific type II collagen was present in alginate and PGA/PLLA scaffolds, independent of the addition of TGF-β1. Collagen type X was present in monolayer cultures as well as in alginate and PGA/PLLA scaffolds. Collagen type I was produced in marginal amounts only. Immortalised human MSCs are a suitable tool to study chondrogenesis in vitro and to screen biomaterials for cartilage tissue engineering applications.

Deutsche Gesellschaft für Chirurgie, 2005

ABSTRACT

Advanced Healthcare Materials, 2013

Targeting bone with anionic macromolecules is a potent approach for the development of novel diag... more Targeting bone with anionic macromolecules is a potent approach for the development of novel diagnostics and therapeutics for bone related diseases. A highly effi cient modular synthesis of dendritic polyglycerol (dPG) polyanion dye conjugates, namely, sulfates, sulfonates, carboxylates, phosphates, phosphonates, and bisphosphonates via click chemistry is presented. By investigating the microarchitecture of stained bone sections with confocal laser scanning microscopy, the bisphosphonate, phosphonate, and phosphate functionalized polymers are identifi ed as strongly penetrating compounds, whereas sulfates, sulfonates, and carboxylates reveal a weaker binding to hydroxyapatite (HA) but a more pronounced affi nity toward collagen. In a quantitative HA binding assay, the affi nity of the dPG sulfonate, sulfate, and carboxylate toward collagen and the exceptional high HA affi nity of the phosphorous containing polyelectrolytes are validated. This shows the potential of dendritic polyphosphates and phosphonates as alternatives to the commonly employed bisphosphonate modifi cation. In cytotoxicity studies with murine fi broblasts, the conjugates have no signifi cant effect on the cell viability at 10 −5 M . All polyanions are taken up into the cells within 24 h. The presented synthetic approach allows versatile extensions for preparing conjugates for selective bone imaging applications, tissue engineering, and drug delivery.

Cells, 2012

Tendon healing is generally a time-consuming process and often leads to a functionally altered re... more Tendon healing is generally a time-consuming process and often leads to a functionally altered reparative tissue. Using degradable scaffolds for tendon reconstruction still remains a compromise in view of the required high mechanical strength of tendons. Regenerative approaches based on natural decellularized allo- or xenogenic tendon extracellular matrix (ECM) have recently started to attract interest. This ECM combines the advantages of its intrinsic mechanical competence with that of providing tenogenic stimuli for immigrating cells mediated, for example, by the growth factors and other mediators entrapped within the natural ECM. A major restriction for their therapeutic application is the mainly cell-associated immunogenicity of xenogenic or allogenic tissues and, in the case of allogenic tissues, also the risk of disease transmission. A survey of approaches for tendon reconstruction using cell-free tendon ECM is presented here, whereby the problems associated with the decellularization procedures, the success of various recellularization strategies, and the applicable cell types will be thoroughly discussed. Encouraging in vivo results using cell-free ECM, as, for instance, in rabbit models, have already been reported. However, in comparison to native tendon, cells remain mostly inhomogeneously distributed in the reseeded ECM and do not align. Hence, future work should focus on the optimization of tendon ECM decellularization and recolonization strategies to restore tendon functionality.

Veterinary Research, 2001

Isolates of the genera Pasteurella and Mannheimia cause a wide variety of diseases of great econo... more Isolates of the genera Pasteurella and Mannheimia cause a wide variety of diseases of great economic importance in poultry, pigs, cattle and rabbits. Antimicrobial agents represent the most powerful tools to control such infections. However, increasing rates of antimicrobial resistance may dramatically reduce the efficacy of the antimicrobial agents used to control Pasteurella and Mannheimia infections. This review presents a short summary of the infections caused by Pasteurella and Mannheimia isolates in food-producing animals and the possibilities of preventing and controlling primary and secondary pasteurellosis. Particular reference is given to antimicrobial chemotherapy and the resistance properties of Pasteurella and Mannheimia isolates. The genetic basis of the most predominant resistance properties such as resistance to β-lactam antibiotics, tetracyclines, aminoglycosides, sulfonamides, and chloramphenicol is discussed. This is depicted with reference to the role of plasmids and transposons in the spread of the resistance genes among Pasteurellaceae and members of other bacterial families and genera. antimicrobial resistance / Pasteurella / Mannheimia / plasmid / transposon / horizontal gene transfer Résumé -Résistance aux antimicrobiens chez Pasteurella et Mannheimia : épidémiologie et bases génétiques. Les bactéries des genres Pasteurella et Mannheimia provoquent une grande variété de maladies ayant des conséquences économiques considérables chez les volailles, les porcs, Vet. Res. 32 (2001) 323-339 323

Macromolecular bioscience, Jan 11, 2016

A stable polymeric network that mimics the highly polyanionic extracellular cartilage matrix stil... more A stable polymeric network that mimics the highly polyanionic extracellular cartilage matrix still remains a great challenge. The main aim of this study is to present the synthesis of dendritic polyglycerol sulfate (dPGS)-based in situ forming hydrogels using strain promoted azide-alkyne cycloaddition reactions. A real time rheological study has been used to characterize the hydrogel properties. The viability of encapsulated human chondrocytes in the different hydrogels are monitored using live-dead staining. Furthermore, type I and II collagen gene have been analyzed. Hydrogels with elastic moduli ranging from 1 to 5 kPa have been prepared by varying the dPGS amount. The chondrocyte viability in dPGS hydrogels is found to be higher than in pure PEG and alginate-based hydrogels after 21 d. The higher cell viability in the dPGS engineered hydrogels can be explained by the fact that dPGS can interact with different proteins responsible for cell growth and proliferation.

BMC Musculoskeletal Disorders, 2015

Anti-inflammatory nanoparticular compounds could represent a strategy to diminish osteoarthritis ... more Anti-inflammatory nanoparticular compounds could represent a strategy to diminish osteoarthritis (OA) progression. The present study was undertaken to prove the uptake of nanoparticular dendritic polyglycerol sulfates (dPGS) by rat-derived articular chondrocytes and to answer the question of whether dPGS could modulate knee joint cartilage degradation in a rat OA model and whether complications could arise. dPGS uptake and cytotoxicity was assessed in cultured primary rat-derived articular chondrocytes. Subsequently, OA was induced in the right knee joints of 12 male Wistar rats by medial collateral ligament and meniscus transection. Unoperated left knees remained as controls. Six weeks post surgery six rats were either treated daily (14 days) with 30 mg/kg dPGS (s.c.) or a similar volume of physiological saline. Animals were analyzed clinically for gait alterations. Explanted knee joints were studied histologically using OA scores according to Mankin (1971), Glasson et al., (2010) and the synovitis score according to Krenn et al., (2006). Liver, spleen and kidneys were analyzed for degenerative changes due to dPGS accumulation. dPGS was taken up after 2 hours by the chondrocytes. Whereas no significant clinical signs of OA could be detected, at the histological level, all operated rat knee joints revealed features of OA in the medial compartment. The values produced by both OA score systems were lower in rats treated with dPGS compared with saline-treated animals. Synovitis score did not significantly differ between the groups. The analyzed organs revealed no degenerative changes. dPGS presented overall cyto- and biocompatibility, no accumulation in metabolizing organs and chondroprotective properties in the osteoarthritic knee joint.

Histology and histopathology

The urokinase-type plasminogen activator receptor (uPAR) plays a critical role in cartilage degra... more The urokinase-type plasminogen activator receptor (uPAR) plays a critical role in cartilage degradation during osteoarthritis as it regulates pericellular proteolysis mediated by serine proteinases. Another important family of proteinases responsible for ECM destruction in arthritis are the matrix metalloproteinases (MMPs). MMPs are regulated by IL-1ß, a cytokine that plays a pivotal role in pathogenesis of osteoarthritis. This study was undertaken to address two questions: 1. Is uPAR-expression regulated by proinflammatory cytokines such as IL-1ß? 2. Does a functional co-localization exist between uPAR and MMPs?

Sensitivity to biomechanical signals and adaptive responses to such stimuli are fundamental prope... more Sensitivity to biomechanical signals and adaptive responses to such stimuli are fundamental properties of articular cartilage. Chondrocytes are specialized cells that utilize mechanical signals to synthesize a mechanically unique extracellular matrix capable of withstanding high loads and shear stresses. Chondrocytes undergo changes in shape and volume when load induces matrix deformation. Changes in hydrostatic pressure, ionic and osmotic composition, interstitial fluid and streaming potentials are sensed by chondrocytes. Responses to these stimuli alter gene expression, matrix composition and biomechanical competence. In this article we focus on the role of mechanosensitive ion channels, !1-integrins and mitogen-activated protein (MAP) kinase kinase pathways in chondrocyte mechanotransduction.

Journal of gravitational physiology: a journal of the International Society for Gravitational Physiology

Weightlessness influences the human immune and hormone system, reduces bone mass, leads to muscle... more Weightlessness influences the human immune and hormone system, reduces bone mass, leads to muscle atrophy and cardiac atrophy. Effects on control mechanisms for proliferation, programmed cell death and differentiation are well documented. The principal aim of this study was to investigate changes of the cytoskeleton in thyroid cells cultured in vector-averaged gravity under clinostat rotation. After 12 hours the formation of multicellular spheroids started. An increase of extracellular matrix proteins and beta 1-integrin was observed. Laser scanning confocal microscopy of ML-1 follicular thyroid carcinoma cells and normal thyroid HTU-5 cells immunostained with anti-cytokeratin to demonstrate these intermediate filaments revealed that cytokeratin filaments extended from centers, were thickened, coalesced and shortened as compared to control cells. Moreover, vimentin was highly disorganized. The vimentin network formed a coiled aggregate closely associated with the nucleus. Western blot analyses of talin, alpha- and beta-tubulin showed a clear increase of these proteins in cells cultured under simulated 0 g. Our data suggest that the effects of microgravity on cultured human thyroid cells are accompanied by noticeable functional cellular changes. Future studies to clarify the pathway that regulate the observed integrin activation and the mechanisms by which they function have to be performed.

Histology and histopathology

The limited ability of articular cartilage to recover from injury, remains an unsolved clinical c... more The limited ability of articular cartilage to recover from injury, remains an unsolved clinical challenge in orthopaedic surgery. Persistent injury of the articular surface can lead to the development of posttraumatic osteoarthritis. The local inflammatory response contributes to the pathogenesis of osteoarthritis by inducing chondrocyte apoptosis and the de-regulation of chondrocyte matrix remodelling. The role of the complement system in contributing to secondary inflammation-mediated cartilage degradation represents a newer field of investigation. The purpose of this review article is to summarize the known complement-mediated actions in cartilage homeostasis and injury. This article focuses on the known effects of complement on secondary chondrocyte apoptosis, and the interplay of the complement system with pro-inflammatory cytokines. Pharmacological therapies related to complement inhibition will be discussed as they potentially represent a new avenue for attenuating the effect of the complement system on cartilage repair.

Inflammation research : official journal of the European Histamine Research Society ... [et al.], Jan 9, 2015

Inflammatory processes driven by cytokines play a crucial role during osteoarthritis (OA) progres... more Inflammatory processes driven by cytokines play a crucial role during osteoarthritis (OA) progression. Dendritic polyglycerol sulfate (dPGS) was analyzed in vitro for its effects on articular chondrocytes, cartilage and cytokines involved in the OA process. The metabolic activity of cultured human articular chondrocytes stimulated for 24 h with dPGS (10(-3)-10(-6) mol/L) was monitored using AlamarBlue(®) assay. The dPGS uptake was studied using fluorescence labeled nanoparticles. Further, chondrocytes were either treated with 10(-6) M dPGS, TNFα (10 ng/mL) alone or with a combination of both. The influence on extracellular matrix components, pro- and anti-inflammatory cytokines, matrix metalloproteinase (MMP)1 and the anaphylatoxin receptor C3aR was analyzed by RTD-PCR, flow cytometry and ELISA. Even at higher dosages (10(-3) mol/L), dPGS did not influence chondrocytes viability. Uptake of dPGS was successfully monitored in human articular chondrocytes and synovial fibroblasts, pene...

Histology and histopathology

Tissue microarrays (TMAs) are an ordered array of tissue cores on a glass slide. They permit immu... more Tissue microarrays (TMAs) are an ordered array of tissue cores on a glass slide. They permit immunohistochemical analysis of numerous tissue sections under identical experimental conditions. The arrays can contain samples of every organ in the human body, or a wide variety of common tumors and obscure clinical cases alongside normal controls. The arrays can also contain pellets of cultured tumor cell lines. These arrays may be used like any histological section for immunohistochemistry and in situ hybridization to detect protein and gene expression. This new technology will allow investigators to analyze numerous biomarkers over essentially identical samples, develop novel prognostic markers and validate potential drug targets. The ability to combine TMA technology with DNA microarrays and proteomics makes it a very attractive tool for analysis of gene expression in clinically stratified tumor specimens and relate expression of each particular protein with clinical outcome. Public d...

Histology and histopathology, 2001

Beta1-integrins were found in the cartilage matrix, suggesting their implication in the assembly ... more Beta1-integrins were found in the cartilage matrix, suggesting their implication in the assembly of its architectural scaffold, but the mechanism for this event is not yet clear. Matrix metalloproteinases (MMPs) may be involved in an integrin-shedding mechanism and matrix beta1-integrins may act to alter MMP activity. To begin to address this question, this study was designed to determine whether beta1-integrins and MMPs are colocalized in the chondrocytes or in the extracellular matrix of cartilage. We investigated high-density cultures of limb buds of 12-day-old mouse embryos by double immunofluorescence, immunoelectron microscopy and by coimmunoprecipitation assays in order to examine the localization of beta1-integrins and matrix metalloproteinases (MMP-1, MMP-3 and MMP-9) in cartilage. It was found, that all investigated MMPs and beta1-integrins were specifically co-localized in high-density cartilage cultures. Immunogold and immunofluorescence labelling of both beta1-integrins...

Histology and histopathology, 2006

Cultivation of phenotypically stable auricular chondrocytes will have applications in autologous ... more Cultivation of phenotypically stable auricular chondrocytes will have applications in autologous chondrocyte transplantation and reconstructive surgery of cartilage. Chondrocytes grown in monolayer culture rapidly dedifferentiate assuming a fibroblast-like morphology and lose their cartilage-specific pattern of gene expression. Three-dimensional high-density culture models mimic more closely the in vivo conditions of cartilage. Therefore, this study was undertaken to test whether the high-density cultures might serve as a suitable model system to acquire phenotypically and functionally differentiated auricular chondrocytes from porcine cartilage. Freshly isolated porcine auricular chondrocytes were cultured for 7 passages in monolayer culture. From each passage (passage 0 and 1-7) cells were introduced to high-density cultures and examined by transmission electron microscopy. Western blotting was used to analyse the expression of cartilage-specific markers, such as collagen type II ...

Muscles, ligaments and tendons journal, 2011

Leukocyte derived pro-inflammatory mediators could be involved in tendon healing and scar formati... more Leukocyte derived pro-inflammatory mediators could be involved in tendon healing and scar formation. Hence, the effect of autologous leukocytes (PBMCs, peripheral blood mononuclear cells and neutrophils) on primary rabbit Achilles tenocytes gene expression was tested in insert assisted co-cultures. Subsequently, tenocytes gene expression of extra-cellular matrix (ECM) components (type I collagen, decorin, fibronectin), the cell-ECM receptor β1-integrin, the angiogenic factor myodulin, ECM degrading matrix-metalloproteinase (MMP)1 and pro-inflammatory cytokines (interleukin [IL]-1β, tumour necrosis factor [TNFα] and IL-6) was analysed. The only significant effect of leukocytes on tenocytes ECM genes expression was a suppression of type I collagen by neutrophils combined with TNFα stimulation. The same effect could be observed analysing the β1-integrin and myodulin gene expression. However, PBMCs up-regulated significantly cytokine and MMP1 gene expression in tenocytes. These in vitro...

European Archives of Oto-Rhino-Laryngology, 2014

Nasal sprays were introduced several years ago to support the treatment of allergic rhinitis. The... more Nasal sprays were introduced several years ago to support the treatment of allergic rhinitis. These sprays may come in direct contact with directly exposed nasoseptal cartilage (e.g. is case of nasoseptal perforation). To date, no studies investigated the effects of nasal sprays on cartilage tissues and cells. Therefore, our aim was to analyze the influence of two different nasal spray types (thixotropic and liposomal) on the vitality of nasoseptal chondrocytes. Human chondrocytes were isolated from surgically dissected tissues. Alternatively, nasal septa (porcine and human) tissue explants were used. The cell or explant cultures were treated with nasal sprays for 4-24 h. As a read-out, cell vitality and gene and protein expression profiles of type I and II collagen, SOX 9 and matrix metalloproteinase MMP-1 were compared to the untreated controls by means of real-time RT-PCR and immunostaining. Using the liposomal, but not thixotropic nasal spray in an explant or chondrocyte in vitro culture led to increased cell death, as compared to the untreated controls. A trend towards suppression of type II collagen and SOX 9 on protein level was found in cultures exposed to liposomal nasal spray, as compared to the controls. The thixotropic nasal spray has not affected the nasoseptal chondrocytes. Further studies with the use of viable nasoseptal cartilage explants and particularly using an in vivo animal model of exposed nasoseptal cartilage are necessary to clear the effect of liposomal spray on chondrocytes.

Bone and Tissue Regeneration Insights, 2014

Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology, 2004

Weightlessness influences the human immune and hormone system, reduces bone mass, leads to muscle... more Weightlessness influences the human immune and hormone system, reduces bone mass, leads to muscle atrophy and cardiac atrophy. Effects on control mechanisms for proliferation, programmed cell death and differentiation are well documented. The principal aim of this study was to investigate changes of the cytoskeleton in thyroid cells cultured in vector-averaged gravity under clinostat rotation. After 12 hours the formation of multicellular spheroids started. An increase of extracellular matrix proteins and beta 1-integrin was observed. Laser scanning confocal microscopy of ML-1 follicular thyroid carcinoma cells and normal thyroid HTU-5 cells immunostained with anti-cytokeratin to demonstrate these intermediate filaments revealed that cytokeratin filaments extended from centers, were thickened, coalesced and shortened as compared to control cells. Moreover, vimentin was highly disorganized. The vimentin network formed a coiled aggregate closely associated with the nucleus. Western bl...

Cell and Tissue Banking, 2014

ABSTRACT Adult mesenchymal stem cells (MSCs) are a promising cell source in tissue engineering du... more ABSTRACT Adult mesenchymal stem cells (MSCs) are a promising cell source in tissue engineering due to their availability, ease of isolation and high proliferative activity. This study was undertaken to investigate whether immortalised human MSC are able to undergo chondrogenic differentiation when cultured in alginate or in resorbable scaffolds. We directly compared chondrogenesis MSCs with that of human nasoseptal chondrocytes. Two previously established human stem cell lines L87/4 and V54-2 immortalised using the SV40 large T-antigen were either cultured in alginate or in polyglycolic acid/poly-L-lactic acid (PGA/PLLA) (90/10) copolymer scaffolds. TGF-β1 was added for induction of chondrogenesis. Human nasoseptal chondrocytes and human fibroblasts were used as controls. Cultures were analysed for sulfated glycosaminoglycans (alcian blue staining) and for the presence of collagen type I, II and X (immunolabelling). SV40 large T-antigen immortalised human MSCs have the potential to undergo chondrogenic differentiation: After 21 days, cartilage-specific type II collagen was present in alginate and PGA/PLLA scaffolds, independent of the addition of TGF-β1. Collagen type X was present in monolayer cultures as well as in alginate and PGA/PLLA scaffolds. Collagen type I was produced in marginal amounts only. Immortalised human MSCs are a suitable tool to study chondrogenesis in vitro and to screen biomaterials for cartilage tissue engineering applications.

Deutsche Gesellschaft für Chirurgie, 2005

ABSTRACT

Advanced Healthcare Materials, 2013

Targeting bone with anionic macromolecules is a potent approach for the development of novel diag... more Targeting bone with anionic macromolecules is a potent approach for the development of novel diagnostics and therapeutics for bone related diseases. A highly effi cient modular synthesis of dendritic polyglycerol (dPG) polyanion dye conjugates, namely, sulfates, sulfonates, carboxylates, phosphates, phosphonates, and bisphosphonates via click chemistry is presented. By investigating the microarchitecture of stained bone sections with confocal laser scanning microscopy, the bisphosphonate, phosphonate, and phosphate functionalized polymers are identifi ed as strongly penetrating compounds, whereas sulfates, sulfonates, and carboxylates reveal a weaker binding to hydroxyapatite (HA) but a more pronounced affi nity toward collagen. In a quantitative HA binding assay, the affi nity of the dPG sulfonate, sulfate, and carboxylate toward collagen and the exceptional high HA affi nity of the phosphorous containing polyelectrolytes are validated. This shows the potential of dendritic polyphosphates and phosphonates as alternatives to the commonly employed bisphosphonate modifi cation. In cytotoxicity studies with murine fi broblasts, the conjugates have no signifi cant effect on the cell viability at 10 −5 M . All polyanions are taken up into the cells within 24 h. The presented synthetic approach allows versatile extensions for preparing conjugates for selective bone imaging applications, tissue engineering, and drug delivery.

Cells, 2012

Tendon healing is generally a time-consuming process and often leads to a functionally altered re... more Tendon healing is generally a time-consuming process and often leads to a functionally altered reparative tissue. Using degradable scaffolds for tendon reconstruction still remains a compromise in view of the required high mechanical strength of tendons. Regenerative approaches based on natural decellularized allo- or xenogenic tendon extracellular matrix (ECM) have recently started to attract interest. This ECM combines the advantages of its intrinsic mechanical competence with that of providing tenogenic stimuli for immigrating cells mediated, for example, by the growth factors and other mediators entrapped within the natural ECM. A major restriction for their therapeutic application is the mainly cell-associated immunogenicity of xenogenic or allogenic tissues and, in the case of allogenic tissues, also the risk of disease transmission. A survey of approaches for tendon reconstruction using cell-free tendon ECM is presented here, whereby the problems associated with the decellularization procedures, the success of various recellularization strategies, and the applicable cell types will be thoroughly discussed. Encouraging in vivo results using cell-free ECM, as, for instance, in rabbit models, have already been reported. However, in comparison to native tendon, cells remain mostly inhomogeneously distributed in the reseeded ECM and do not align. Hence, future work should focus on the optimization of tendon ECM decellularization and recolonization strategies to restore tendon functionality.

Veterinary Research, 2001

Isolates of the genera Pasteurella and Mannheimia cause a wide variety of diseases of great econo... more Isolates of the genera Pasteurella and Mannheimia cause a wide variety of diseases of great economic importance in poultry, pigs, cattle and rabbits. Antimicrobial agents represent the most powerful tools to control such infections. However, increasing rates of antimicrobial resistance may dramatically reduce the efficacy of the antimicrobial agents used to control Pasteurella and Mannheimia infections. This review presents a short summary of the infections caused by Pasteurella and Mannheimia isolates in food-producing animals and the possibilities of preventing and controlling primary and secondary pasteurellosis. Particular reference is given to antimicrobial chemotherapy and the resistance properties of Pasteurella and Mannheimia isolates. The genetic basis of the most predominant resistance properties such as resistance to β-lactam antibiotics, tetracyclines, aminoglycosides, sulfonamides, and chloramphenicol is discussed. This is depicted with reference to the role of plasmids and transposons in the spread of the resistance genes among Pasteurellaceae and members of other bacterial families and genera. antimicrobial resistance / Pasteurella / Mannheimia / plasmid / transposon / horizontal gene transfer Résumé -Résistance aux antimicrobiens chez Pasteurella et Mannheimia : épidémiologie et bases génétiques. Les bactéries des genres Pasteurella et Mannheimia provoquent une grande variété de maladies ayant des conséquences économiques considérables chez les volailles, les porcs, Vet. Res. 32 (2001) 323-339 323