EMR+: Vorstellung einer neuen endoskopischen Resektionsmethode im ex-vivo Model

SummaryThe APTT has been considered the most suitable candidate to monitor the anticoagulant activity of hirudin. However, its use is hampered by problems of standardization, which make the results heavily dependent on the responsiveness of the reagent used. Our aim was to investigate if this different responsiveness of different reagents when added in vitro is to be confirmed in an ex vivo study.Two different doses of r-hirudin (CGP 39393), 0.3 mg/kg and 1 mg/kg, were administered subcutaneously to 20 New Zealand male rabbits, and the differences in prolongation of APTT 2 and 12 h later were compared, using 8 widely used commercial reagents. All groups exhibited a significant prolongation of APTT 2 h after sc administration of hirudin, both at low and high doses. But this prolongation persisted 12 h later only when the PTTa reagent (Boehringer Mannheim) was used. In general, hirudin prolonged the APTT most with the silica- based reagents.In a further study, we compared the same APTT reagents in an in vitro study in which normal pooled plasma was mixed with increasing amount of hirudin. We failed to confirm a higher sensitivity for silica- containing reagents. Thus, we conclude that subcutaneous administration of hirudin prolongs the APTT most with the silica-based reagents, but this effect is exclusive for the ex vivo model.

Download Full-text

Newly designed colonic ex-vivo model with real flat lesions for learning endoscopic submucosal dissection in western countries: double evaluation including experts' assessment and learning curve study on fellows

10.26226/morressier.57c5383dd462b80296c9c275 ◽

2016 ◽

Author(s):

Jean-Michel Gonzalez

Keyword(s):

Learning Curve ◽

Endoscopic Submucosal Dissection ◽

Ex Vivo ◽

Ex Vivo Model ◽

Western Countries ◽

Submucosal Dissection ◽

Flat Lesions

Download Full-text

Anti-Inflammatory Effects of Novel Standardized Platelet Rich Plasma Releasates on Knee Osteoarthritic Chondrocytes and Cartilage in vitro

Current Pharmaceutical Biotechnology ◽

10.2174/1389201020666190619111118 ◽

2019 ◽

Vol 20 (11) ◽

pp. 920-933 ◽

Cited By ~ 3

Author(s):

Lucía Gato-Calvo ◽

Tamara Hermida-Gómez ◽

Cristina R. Romero ◽

Elena F. Burguera ◽

Francisco J. Blanco

Keyword(s):

Gene Expression ◽

Ex Vivo ◽

Platelet Rich Plasma ◽

Cartilage Explants ◽

Ex Vivo Model ◽

Chondrocyte Viability ◽

Platelet Concentration ◽

The Absolute ◽

Anti Inflammatory

Background: Platelet Rich Plasma (PRP) has recently emerged as a potential treatment for osteoarthritis (OA), but composition heterogeneity hampers comparison among studies, with the result that definite conclusions on its efficacy have not been reached. Objective: 1) To develop a novel methodology to prepare a series of standardized PRP releasates (PRP-Rs) with known absolute platelet concentrations, and 2) To evaluate the influence of this standardization parameter on the anti-inflammatory properties of these PRP-Rs in an in vitro and an ex vivo model of OA. Methods: A series of PRPs was prepared using the absolute platelet concentration as the standardization parameter. Doses of platelets ranged from 0% (platelet poor plasma, PPP) to 1.5·105 platelets/µl. PRPs were then activated with CaCl2 to obtain releasates (PRP-R). Chondrocytes were stimulated with 10% of each PRP-R in serum-free culture medium for 72 h to assess proliferation and viability. Cells were co-stimulated with interleukin (IL)-1β (5 ng/ml) and 10% of each PRP-R for 48 h to determine the effects on gene expression, secretion and intra-cellular content of common markers associated with inflammation, catabolism and oxidative stress in OA. OA cartilage explants were co-stimulated with IL-1β (5 ng/ml) and 10% of either PRP-R with 0.75·105 platelets/µl or PRP-R with 1.5·105 platelets/µl for 21 days to assess matrix inflammatory degradation. Results: Chondrocyte viability was not affected, and proliferation was dose-dependently increased. The gene expression of all pro-inflammatory mediators was significantly and dose-independently reduced, except for that of IL-1β and IL-8. Immunoblotting corroborated this effect for inducible NO synthase (NOS2). Secreted matrix metalloproteinase-13 (MMP-13) was reduced to almost basal levels by the PRP-R from PPP. Increasing platelet dosage led to progressive loss to this anti-catabolic ability. Safranin O and toluidine blue stains supported the beneficial effect of low platelet dosage on cartilage matrix preservation. Conclusion: We have developed a methodology to prepare PRP releasates using the absolute platelet concentration as the standardization parameter. Using this approach, the composition of the resulting PRP derived product is independent of the donor initial basal platelet count, thereby allowing the evaluation of its effects objectively and reproducibly. In our OA models, PRP-Rs showed antiinflammatory, anti-oxidant and anti-catabolic properties. Platelet enrichment could favor chondrocyte proliferation but is not necessary for the above effects and could even be counter-productive.

Download Full-text

Anti-pseudomonad Activity of Manuka Honey and Antibiotics in a Specialized ex vivo Model Simulating Cystic Fibrosis Lung Infection

Frontiers in Microbiology ◽

10.3389/fmicb.2019.00869 ◽

2019 ◽

Vol 10 ◽

Cited By ~ 5

Author(s):

Aled E. L. Roberts ◽

Lydia C. Powell ◽

Manon F. Pritchard ◽

David W. Thomas ◽

Rowena E. Jenkins

Keyword(s):

Cystic Fibrosis ◽

Ex Vivo ◽

Lung Infection ◽

Cystic Fibrosis Lung ◽

Manuka Honey ◽

Ex Vivo Model

Download Full-text

100P Patient-derived tissue cultures of esophagogastric-junction cancer (EGJC) and gastric cancer (GC): An ex vivo model to study individual response of immunotherapy

Annals of Oncology ◽

10.1016/j.annonc.2020.10.589 ◽

2020 ◽

Vol 31 ◽

pp. S1457

Author(s):

J. Körfer ◽

M. Hußtegge ◽

I. Gockel ◽

A. Monecke ◽

G. Schumacher ◽

...

Keyword(s):

Gastric Cancer ◽

Esophagogastric Junction ◽

Ex Vivo ◽

Individual Response ◽

Tissue Cultures ◽

Ex Vivo Model ◽

Esophagogastric Junction Cancer

Download Full-text

Scleraxis expressing scleral cells respond to inflammatory stimulation

Histochemistry and Cell Biology ◽

10.1007/s00418-021-01985-y ◽

2021 ◽

Author(s):

Ghada Atta ◽

Falk Schroedl ◽

Alexandra Kaser-Eichberger ◽

Gabriel Spitzer ◽

Andreas Traweger ◽

...

Keyword(s):

Ex Vivo ◽

Interleukin 1 ◽

Collagen Fibre ◽

Tissue Growth ◽

Collagen Degradation ◽

Ocular Tissue ◽

Marker Genes ◽

Ex Vivo Model ◽

Tendon Cell ◽

Fibre Degradation

AbstractThe sclera is an ocular tissue rich of collagenous extracellular matrix, which is built up and maintained by relatively few, still poorly characterized fibroblast-like cells. The aims of this study are to add to the characterization of scleral fibroblasts and to examine the reaction of these fibroblasts to inflammatory stimulation in an ex vivo organotypic model. Scleras of scleraxis-GFP (SCX-GFP) mice were analyzed using immunohistochemistry and qRT-PCR for the expression of the tendon cell associated marker genes scleraxis (SCX), mohawk and tenomodulin. In organotypic tissue culture, explanted scleras of adult scleraxis GFP reporter mice were exposed to 10 ng/ml recombinant interleukin 1-ß (IL1-ß) and IL1-ß in combination with dexamethasone. The tissue was then analyzed by immunofluorescence staining of the inflammation- and fibrosis-associated proteins IL6, COX-2, iNOS, connective tissue growth factor, MMP2, MMP3, and MMP13 as well as for collagen fibre degradation using a Collagen Hybridizing Peptide (CHP) binding assay. The mouse sclera displayed a strong expression of scleraxis promoter-driven GFP, indicating a tendon cell-like phenotype, as well as expression of scleraxis, tenomodulin and mohawk mRNA. Upon IL1-ß stimulation, SCX-GFP+ cells significantly upregulated the expression of all proteins analysed. Moreover, IL1-ß stimulation resulted in significant collagen degradation. Adding the corticosteroid dexamethasone significantly reduced the response to IL1-ß stimulation. Collagen degradation was significantly enhanced in the IL1-ß group. Dexamethasone demonstrated a significant rescue effect. This work provides insights into the characteristics of scleral cells and establishes an ex vivo model of scleral inflammation.

Download Full-text

Pharmacological ablation of astrocytes reduces Aβ degradation and synaptic connectivity in an ex vivo model of Alzheimer’s disease

Journal of Neuroinflammation ◽

10.1186/s12974-021-02117-y ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Nicola Davis ◽

Bibiana C. Mota ◽

Larissa Stead ◽

Emily O. C. Palmer ◽

Laura Lombardero ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Culture Media ◽

Ex Vivo ◽

Wild Type ◽

Insulin Degrading Enzyme ◽

Ex Vivo Model ◽

Model Of Alzheimer’S Disease ◽

Aβ Clearance ◽

5Xfad Mice

Abstract Background Astrocytes provide a vital support to neurons in normal and pathological conditions. In Alzheimer’s disease (AD) brains, reactive astrocytes have been found surrounding amyloid plaques, forming an astrocytic scar. However, their role and potential mechanisms whereby they affect neuroinflammation, amyloid pathology, and synaptic density in AD remain unclear. Methods To explore the role of astrocytes on Aβ pathology and neuroinflammatory markers, we pharmacologically ablated them in organotypic brain culture slices (OBCSs) from 5XFAD mouse model of AD and wild-type (WT) littermates with the selective astrocytic toxin L-alpha-aminoadipate (L-AAA). To examine the effects on synaptic circuitry, we measured dendritic spine number and size in OBCSs from Thy-1-GFP transgenic mice incubated with synthetic Aβ42 or double transgenics Thy-1-GFP/5XFAD mice treated with LAAA or vehicle for 24 h. Results Treatment of OBCSs with L-AAA resulted in an increased expression of pro-inflammatory cytokine IL-6 in conditioned media of WTs and 5XFAD slices, associated with changes in microglia morphology but not in density. The profile of inflammatory markers following astrocytic loss was different in WT and transgenic cultures, showing reductions in inflammatory mediators produced in astrocytes only in WT sections. In addition, pharmacological ablation of astrocytes led to an increase in Aβ levels in homogenates of OBCS from 5XFAD mice compared with vehicle controls, with reduced enzymatic degradation of Aβ due to lower neprilysin and insulin-degrading enzyme (IDE) expression. Furthermore, OBSCs from wild-type mice treated with L-AAA and synthetic amyloid presented 56% higher levels of Aβ in culture media compared to sections treated with Aβ alone, concomitant with reduced expression of IDE in culture medium, suggesting that astrocytes contribute to Aβ clearance and degradation. Quantification of hippocampal dendritic spines revealed a reduction in their density following L-AAA treatment in all groups analyzed. In addition, pharmacological ablation of astrocytes resulted in a decrease in spine size in 5XFAD OBCSs but not in OBCSs from WT treated with synthetic Aβ compared to vehicle control. Conclusions Astrocytes play a protective role in AD by aiding Aβ clearance and supporting synaptic plasticity.

Download Full-text