Cytotoxicity of snake venom Lys49 PLA2-like myotoxin on rat cardiomyocytes ex vivo does not involve a direct action on the contractile apparatus

AbstractViperid snake venoms contain a unique family of cytotoxic proteins, the Lys49 PLA2 homologs, which are devoid of enzymatic activity but disrupt the integrity of cell membranes. They are known to induce skeletal muscle damage and are therefore named ‘myotoxins’. Single intact and skinned (devoid of membranes and cytoplasm but with intact sarcomeric proteins) rat cardiomyocytes were used to analyze the cytotoxic action of a myotoxin, from the venom of Bothrops asper. The toxin induced rapid hypercontraction of intact cardiomyocytes, associated with an increase in the cytosolic concentration of calcium and with cell membrane disruption. Hypercontraction of intact cardiomyocytes was abrogated by the myosin inhibitor para-aminoblebbistatin (AmBleb). No toxin-induced changes of key parameters of force development were observed in skinned cardiomyocytes. Thus, although myosin is a key effector of the observed hypercontraction, a direct effect of the toxin on the sarcomeric proteins -including the actomyosin complex- is not part of the mechanism of cytotoxicity. Owing to the sensitivity of intact cardiomyocytes to the cytotoxic action of myotoxin, this ex vivo model is a valuable tool to explore in further detail the mechanism of action of this group of snake venom toxins.

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1849: Systematic Evaluation of 21μm Thulium Laser Device for Treatment of Benign Prostatic Enlargement in an Ex-VIVO Model

The Journal of Urology ◽

10.1016/s0022-5347(18)32022-6 ◽

2007 ◽

Vol 177 (4S) ◽

pp. 614-614 ◽

Cited By ~ 3

Author(s):

Gunnar Wendt-Nordahl ◽

Stefanie Huckele ◽

Patrick Honeck ◽

Peter Aiken ◽

Thomas Knoll ◽

...

Keyword(s):

Ex Vivo ◽

Systematic Evaluation ◽

Thulium Laser ◽

Laser Device ◽

Benign Prostatic Enlargement ◽

Ex Vivo Model ◽

Prostatic Enlargement

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Assessment of phosphodiesterase inhibition and endothelin receptor antagonism combination therapy for pulmonary hypertension in a human ex vivo model

The Thoracic and Cardiovascular Surgeon ◽

10.1055/s-0032-1332505 ◽

2013 ◽

Vol 61 (S 01) ◽

Author(s):

M Ried ◽

M Hönicka ◽

T Potzger ◽

R Neu ◽

Z Sziklavari ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Combination Therapy ◽

Ex Vivo ◽

Endothelin Receptor ◽

Phosphodiesterase Inhibition ◽

Ex Vivo Model ◽

Receptor Antagonism

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Porcine small intestine, a good ex vivo model to investigate absorption and metabolism of natural products

10.1055/s-0037-1608241 ◽

2017 ◽

Author(s):

J Houriet ◽

YE Arnold ◽

C Petit ◽

YN Kalia ◽

JL Wolfender

Keyword(s):

Natural Products ◽

Small Intestine ◽

Ex Vivo ◽

Ex Vivo Model

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Effects of Two Different Doses of Hirudin on APTT, Determined with Eight Different Reagents

Thrombosis and Haemostasis ◽

10.1055/s-0038-1653754 ◽

1995 ◽

Vol 73 (02) ◽

pp. 219-222 ◽

Cited By ~ 4

Author(s):

Manuel Monreal ◽

Luis Monreal ◽

Rafael Ruiz de Gopegui ◽

Yvonne Espada ◽

Ana Maria Angles ◽

...

Keyword(s):

Ex Vivo ◽

Anticoagulant Activity ◽

Subcutaneous Administration ◽

In Vitro Study ◽

Ex Vivo Model ◽

Suitable Candidate ◽

Significant Prolongation ◽

High Doses ◽

Different Doses

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.

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

10.1055/s-0039-1695530 ◽

2019 ◽

Author(s):

RF Knoop ◽

E Wedi ◽

V Ellenrieder ◽

A Neesse ◽

S Kunsch

Keyword(s):

Ex Vivo ◽

Ex Vivo Model

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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

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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.

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