Der Einfluss von TNF-(alpha) und IL-1(beta) auf die Knorpeldestruktion durch synoviale Fibroblasten: Untersuchungen in einem in vitro-Knorpeldestruktions-Assay als Modell für die Gelenkzerstörung bei der rheumatoiden Arthritis

Die rheumatoide Arthritis (RA) ist eine chronisch-entzündliche Systemerkrankung mit charakteristischer Hyperplasie der Synovialmembran und Zerstörung der befallenen Gelenke. Hierbei wird den aktivierten synovialen Fibroblasten (SFB) eine besondere pathogenetische Bedeutung zugeschrieben, da sie durch die Produktion von pro-inflammatorischen Zytokinen und matrixdegradierenden Enzymen maßgeblich an der Gelenkentzündung und der Knorpeldestruktion in der RA beteiligt sind. Das Ziel der vorliegenden Arbeit war es, die relative Bedeutung von RA-SFB und Chondrozyten bei der Knorpeldestruktion zu untersuchen. Dabei war von besonderem Interesse, welche biochemischen und zellbiologischen Prozesse zur Destruktion des meist noch nicht geschädigten Gelenkknorpels in den frühen Stadien der RA beitragen. In dem Modell wurde das destruktive Potential von SFB aus Patienten mit RA bzw. mit Osteoarthrose (OA, als primär nicht-entzündliche Kontrolle) vergleichend untersucht. Dazu wurden die SFB mit vitalen bzw. avitalen bovinen Gelenkknorpelexplantaten über einen Zeitraum von 14 d bzw. 42 d unter Zusatz von TNF-α, IL-1β oder der Kombination von TNF- α/IL-1β kokultiviert. Zur Analyse der induzierten Vorgänge wurde eine Vielzahl von Parametern des Knorpeldestruktionsprozesses im Knorpel bzw. in den SFB untersucht (Matrixabbau und - Neosynthese, matrixdegradierende Proteasen und ihre Inhibitoren, pro-inflammatorische Zytokine, morphologische Veränderungen). Das Modell stellt insgesamt ein geeignetes Werkzeug dar, um die Wechselwirkungen zwischen SFB, Chondrozyten und der Knorpelmatrix in vitro zu untersuchen und die Mechanismen des in vivo ablaufenden Destruktionsprozesses in den betroffenen rheumatischen Gelenken besser zu verstehen. Es stellt eine wirkungsvolle Alternative zu experimentell sehr aufwendigen und tierschutzrechtlich problematischen in vivo-Tiermodellen dar

Self-Assembly of Core-Shell Hybrid Nanoparticles by Directional Crystallization of Grafted Polymers

Nanoparticle self-assembly is an efficient bottom-up strategy for the creation of nanostructures. In the standard approach, ligands are grafted on the surfaces of nanoparticles to keep them separated and control interparticle interactions. Ligands then remain secondary and usually are not expected to order significantly during superstructure formation. Here, we investigate how ligands can play a more primary role in the formation of inorganic-organic hybrid materials. We graft poly(2-iso-propyl-2-oxazoline) (PiPrOx) as a crystallizable shell onto SiO$_2$ nanoparticles. By varying the PiPrOx grafting density, solution stability, and nanoparticle aggregation behavior can be controlled. Upon prolonged heating, anisotropic nanostructures form in conjunction with the crystallization of the ligands. Self-assembly of hybrid PiPrOx@SiO$_2$ (shell@core) nanoparticles proceeds in two steps: First, rapid formation of amorphous aggregates via gelation, mediated by the interaction between nanoparticles through grafted polymers; second, slow radial growth of fibers via directional crystallization, governed by the incorporation of crystalline ribbons formed from unbound polymers coupling to the grafted polymer shell. Our work reveals how crystallization-driven self-assembly of ligands can create intricate hybrid nanostructures.Comment: 12 pages, 5 figure

The Effect of Temperature on Gill Aquaporin 3 (AQP3) mRNA Expression in Killifish (\u3cem\u3eFundulus heteroclitus\u3c/em\u3e): Correlations With Branchial Osmotic Water Permeability

The idea was tested that killifish gill cell surface membrane water channel proteins (aquaporin 3) might be responsible for water flows into and out of the gills, that increase with temperature. There are several factors that determine the level of gill water flow: these include the measurement temperature used and the temperature to which fish are acclimatized. Changes in aquaporin 3 may account for changes in gill water flow occurring due to differences in fish acclimation temperature

In vitro model for the analysis of synovial fibroblast-mediated degradation of intact cartilage

INTRODUCTION: Activated synovial fibroblasts are thought to play a major role in the destruction of cartilage in chronic, inflammatory rheumatoid arthritis (RA). However, profound insight into the pathogenic mechanisms and the impact of synovial fibroblasts in the initial early stages of cartilage destruction is limited. Hence, the present study sought to establish a standardised in vitro model for early cartilage destruction with native, intact cartilage in order to analyse the matrix-degrading capacity of synovial fibroblasts and their influence on cartilage metabolism. METHODS: A standardised model was established by co-culturing bovine cartilage discs with early-passage human synovial fibroblasts for 14 days under continuous stimulation with TNF-α, IL-1β or a combination of TNF-α/IL-1β. To assess cartilage destruction, the co-cultures were analysed by histology, immunohistochemistry, electron microscopy and laser scanning microscopy. In addition, content and/or neosynthesis of the matrix molecules cartilage oligomeric matrix protein (COMP) and collagen II was quantified. Finally, gene and protein expression of matrix-degrading enzymes and pro-inflammatory cytokines were profiled in both synovial fibroblasts and cartilage. RESULTS: Histological and immunohistological analyses revealed that non-stimulated synovial fibroblasts are capable of demasking/degrading cartilage matrix components (proteoglycans, COMP, collagen) and stimulated synovial fibroblasts clearly augment chondrocyte-mediated, cytokine-induced cartilage destruction. Cytokine stimulation led to an upregulation of tissue-degrading enzymes (aggrecanases I/II, matrix-metalloproteinase (MMP) 1, MMP-3) and pro-inflammatory cytokines (IL-6 and IL-8) in both cartilage and synovial fibroblasts. In general, the activity of tissue-degrading enzymes was consistently higher in co-cultures with synovial fibroblasts than in cartilage monocultures. In addition, stimulated synovial fibroblasts suppressed the synthesis of collagen type II mRNA in cartilage. CONCLUSIONS: The results demonstrate for the first time the capacity of synovial fibroblasts to degrade intact cartilage matrix by disturbing the homeostasis of cartilage via the production of catabolic enzymes/pro-inflammatory cytokines and suppression of anabolic matrix synthesis (i.e., collagen type II). This new in vitro model may closely reflect the complex process of early stage in vivo destruction in RA and help to elucidate the role of synovial fibroblasts and other synovial cells in this process, and the molecular mechanisms involved in cartilage degradation

Investigating the impact of cleaning treatments on polystyrene using SEM, AFM and ToF–SIMS

Abstract Concerns about the stability of plastic artefacts are commonly expressed when discussing the conservation of modern materials. One of the factors affecting the degradation of plastics is the presence of soil, degradation products and other contaminants on the surface. Cleaning treatments for plastic artefacts may therefore increase their stability as well as improving their visual appearance. While past studies have shown that dry, aqueous and solvent cleaning can visibly damage a plastic surface, the chemical and physical changes occurring to the surface at the micro-scale have been largely unexplored. In this work time-of-flight secondary ion mass spectrometry (ToF–SIMS) has been used in conjunction with atomic force microscopy (AFM) and scanning electron microscopy (SEM) to examine the effect of cleaning treatments on the surface of sheet polystyrene. Chemometric analysis of the ToF–SIMS data reveals the presence of surfactant residues and contamination from cleaning agents while physical damage in the form of scratching has been characterised using AFM and SEM. It is anticipated such work will assist in informing future conservation treatments for plastics

Synthesis and Solution Properties of Double Hydrophilic Poly(ethylene oxide)-block-poly(2-ethyl-2-oxazoline) (PEO-b-PEtOx) Star Block Copolymers

We demonstrate the synthesis of star-shaped poly(ethylene oxide)-block-poly(2-ethyl-2-oxazoline) [PEOm-b-PEtOxn]x block copolymers with eight arms using two different approaches, either the “arm-first” or the “core-first” strategy. Different lengths of the outer PEtOx blocks ranging from 16 to 75 repeating units were used, and the obtained materials [PEO28-b-PEtOxx]8 were characterized via size exclusion chromatography (SEC), nuclear magnetic resonance spectroscopy (NMR), and Fourier-transform infrared spectroscopy (FT-IR) measurements. First investigations regarding the solution behavior in water as a non-selective solvent revealed significant differences. Whereas materials synthesized via the “core-first” method seemed to be well soluble (unimers), aggregation occurred in the case of materials synthesized by the “arm-first” method using copper-catalyzed azide-alkyne click chemistry