Abstract P350: Interstitial Volume Regulation in the Heart: Mechanistic Insights from ex Vivo Fluid Dynamics in Pig Myocardia

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Maria P McGee ◽  
Michael Morykwas ◽  
Jim Jordan ◽  
Louis Argenta
Keyword(s):  
Fluid Dynamics ◽  
Ex Vivo ◽  
Myocardial Edema ◽  
Lymphatic Drainage ◽  
Control Mechanisms ◽  
Pressure Gradients ◽  
Interstitial Volume ◽  
The Media ◽  
Fluid Transfer

Developing and testing specific therapies for myocardial edema require understanding their mode and site of action. However, parsing determinants of interstitial volume/pressure relationships in vivo is difficult, particularly in the myocardium, where rhythmic contractions add to the confounding components of fluid-transfer driving pressures. Here, we describe a novel ex-vivo model system based on osmotic stress techniques and illustrate its application to analyses of local myocardial fluid dynamics that exclude systemic influences and systole/diastole compressive cycles. Freshly harvested ventricular explants were equilibrated in physiologic media at colloidosmotic pressures ranging from 3 to 219 mmHg, and fluid transfer in/out was measured gravimetrically as a function of time and pressure. The relationship between the change in explant volume and the imposed colloidosmotic pressure of the media was linear. The hydration potential , defined empirically as the pressure at which explant volume did not change, was calculated from the abscissa intercept at volume change = 0 , and the compliance from the slope of volume/pressure regression lines. Fluid-transfer rates and energies were derived from volume versus time trajectories measured at 4 and 37 °C. Hydration potential was 71.3 ± 10.6 and 23.0 ± 15.2 mmHg at 4 and 37°C (significant, P = 0.002), while compliance was 1.09 ± 0.3 and 1.22 ± 0.2 µl/g/ mmHg (not significant, P = 0.2, n = 5). Temperature-dependent differences between in/out flow rates were also significant, giving experimental activation energies of −5.9 ± 2.2 and 1.4 ± 0.7 kcal/mol for inflow and outflow, respectively. Results show that at physiologic temperatures, even without vascular hydrostatic pressure gradients and lymphatic drainage, the myocardial bias toward interstitial fluid efflux persists. These findings are consistent with local fluid-control mechanisms actuated by colloidosmotic and tensional forces rather than passive changes in flow resistance. This new approach allows quantitative evaluation of interstitial components of Starling’s forces and should help in mechanistic preclinical characterization of treatments to correct interstitial myocardial edema.

scholarly journals Extracellular Vesicles Derived From Human Corneal Endothelial Cells Inhibit Proliferation of Human Corneal Endothelial Cells

2021 ◽  
Author(s):  
Mohit Parekh ◽  
Hefin Rhys ◽  
Tiago Ramos ◽  
Stefano Ferrari ◽  
Sajjad Ahmad
Keyword(s):  
Endothelial Cells ◽  
Extracellular Vesicles ◽  
Ex Vivo ◽  
Treatment Options ◽  
Proliferative Capacity ◽  
Corneal Endothelial Cells ◽  
Human Corneal Endothelial Cells ◽  
The Media

Abstract Corneal endothelial cells (CEnCs) are a monolayer of hexagonal cells that are responsible for maintaining the function and transparency of the cornea. Damage or dysfunction of CEnCs could lead to blindness. Human CEnCs (HCEnCs) have shown limited proliferative capacity in vivo hence, their maintenance is crucial. Extracellular vesicles (EVs), are responsible for inter- and intra-cellular communication, proliferation, cell-differentiation, migration, and many other complex biological processes. Therefore, we investigated the effect of EVs (derived from human corneal endothelial cell line – HCEC-12) on corneal endothelial cells. HCEC-12 cells were starved with serum-depleted media for 72 hours. The media was ultracentrifuged at 100,000xg to isolate the EVs. EV counting, characterization, internalization and localization were performed using NanoSight, flow cytometry, Dil labelling and confocal microscopy respectively. HCEC-12 and HCEnCs were cultured with media supplemented with EVs. Extracted EVs showed a homogeneous mixture of exosomes and microvesicles. Cells with EVs decreased the proliferation rate; increased apoptosis and cell size; showed poor wound healing response in vitro and on ex vivo human, porcine, and rabbit CECs. Thirteen miRNAs were found in the EV sample using next generation sequencing. We observed that increased cellular uptake of EVs by CECs limit the proliferative capacity of HCEnCs. These preliminary data may help in understanding the pathology of corneal endothelial dysfunction and provide further insights in the development of future therapeutic treatment options.

scholarly journals Ex vivo mouse hematopoietic stem cell expansion using polyvinyl alcohol

2019 ◽  
Author(s):  
Adam C. Wilkinson ◽  
Reiko Ishida ◽  
Satoshi Yamazaki ◽  
Hiromitsu Nakauchi
Keyword(s):  
Polyvinyl Alcohol ◽  
Serum Albumin ◽  
Ex Vivo ◽  
Culture Conditions ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Biological Contaminants ◽  
The Media ◽  
Mouse Hematopoietic Stem Cell

Abstract The self-renewal of multipotent hematopoietic stem cells (HSCs) is key for life-long maintenance of hematopoiesis and the curative capacity of clinical bone marrow transplantation. However, while in vivo HSC self-renewal has been well-described, existing culture conditions poorly support ex vivo HSC self-renewal and afford a very limited window to study or modify HSCs in-a-dish. Here, we describe a simple culture platform that supports functional mouse HSCs ex vivo for 1-2 months. Rather than containing serum albumin, the media uses the synthetic polymer polyvinyl alcohol (PVA). PVA represents an inexpensive and chemically-defined alternative to serum albumin supplements, which have long represented a major source of biological contaminants and batch-to-batch variability in HSC cultures. This novel culture system therefore provides a useful platform to expand and interrogate mouse HSCs.

scholarly journals Differences in Regulatory Mechanisms Induced by β-Lactoglobulin and κ-Casein in Cow’s Milk Allergy Mouse Model–In Vivo and Ex Vivo Studies

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 349
Author(s):  
Dagmara Złotkowska ◽  
Emilia Stachurska ◽  
Ewa Fuc ◽  
Barbara Wróblewska ◽  
Anita Mikołajczyk ◽  
...  
Keyword(s):  
Immune Responses ◽  
Ex Vivo ◽  
Milk Proteins ◽  
Interleukin 10 ◽  
Control Mechanisms ◽  
Applied Model ◽  
Allergenic Potential ◽  
Cd4 Lymphocyte ◽  
Β Lactoglobulin

The presence of various proteins, including modified ones, in food which exhibit diverse immunogenic and sensitizing properties increases the difficulty of predicting host immune responses. Still, there is a lack of sufficiently reliable and comparable data and research models describing allergens in dietary matrices. The aim of the study was to estimate the immunomodulatory effects of β-lactoglobulin (β-lg) in comparison to those elicited by κ-casein (κ-CN), in vivo and ex vivo, using naïve splenocytes and a mouse sensitization model. Our results revealed that the humoral and cellular responses triggered by β-lg and κ-CN were of diverse magnitudes and showed different dynamics in the induction of control mechanisms. β-Lg turned out to be more immunogenic and induced a more dominant Th1 response than κ-CN, which triggered a significantly higher IgE response. For both proteins, CD4+ lymphocyte profiles correlated with CD4+CD25+ and CD4+CD25+Foxp3+ T cells induction and interleukin 10 secretion, but β-lg induced more CD4+CD25+Foxp3- Tregs. Moreover, ex vivo studies showed the risk of interaction of immune responses to different milk proteins, which may exacerbate allergy, especially the one caused by β-lg. In conclusion, the applied model of in vivo and ex vivo exposure to β-lg and κ-CN showed significant differences in immunoreactivity of the tested proteins (κ-CN demonstrated stronger allergenic potential than β-lg), and may be useful for the estimation of allergenic potential of various food proteins, including those modified in technological processes.

scholarly journals Ex vivo signatures of myocardial edema by in vivo T2-CMR in a novel large animal model of NSTE-ACS

2013 ◽  
Vol 15 (S1) ◽  
Author(s):  
Henry Chang ◽  
Tam Tran ◽  
George Billman ◽  
Mark W Julian ◽  
Robert Hamlin ◽  
...  
Keyword(s):  
Animal Model ◽  
Ex Vivo ◽  
Myocardial Edema ◽  
Large Animal Model ◽  
Large Animal

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

Antithrombotic Effects and Bleeding Time Prolongation with Synthetic Platelet GPIIb/llla Inhibitors in Animal Models of Platelet-Mediated Thrombosis

1994 ◽  
Vol 71 (01) ◽  
pp. 095-102 ◽  
Author(s):  
Désiré Collen ◽  
Hua Rong Lu ◽  
Jean-Marie Stassen ◽  
Ingrid Vreys ◽  
Tsunehiro Yasuda ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Bleeding Time ◽  
Bolus Injection ◽  
Cell Injury ◽  
Ex Vivo ◽  
Thrombus Formation ◽  
Femoral Vein ◽  
Thrombotic Occlusion ◽  
Antithrombotic Effects

SummaryCyclic Arg-Gly-Asp (RGD) containing synthetic peptides such as L-cysteine, N-(mercaptoacetyl)-D-tyrosyl-L-arginylglycyl-L-a-aspartyl-cyclic (1→5)-sulfide, 5-oxide (G4120) and acetyl-L-cysteinyl-L-asparaginyl-L-prolyl-L-arginyl-glycyl-L-α-aspartyl-[0-methyltyrosyl]-L-arginyl-L-cysteinamide, cyclic 1→9-sulfide (TP9201) bind with high affinity to the platelet GPIIb/IIIa receptor.The relationship between antithrombotic effect, ex vivo platelet aggregation and bleeding time prolongation with both agents was studied in hamsters with a standardized femoral vein endothelial cell injury predisposing to platelet-rich mural thrombosis, and in dogs with a carotid arterial eversion graft inserted in the femoral artery. Intravenous administration of G4120 in hamsters inhibited in vivo thrombus formation with a 50% inhibitory bolus dose (ID50) of approximately 20 μg/kg, ex vivo ADP-induccd platelet aggregation with ID50 of 10 μg/kg, and bolus injection of 1 mg/kg prolonged the bleeding time from 38 ± 9 to 1,100 ± 330 s. Administration of TP9201 in hamsters inhibited in vivo thrombus formation with ID50 of 30 μg/kg, ex vivo platelet aggregation with an ID50 of 50 μg/kg and bolus injection of 1 mg/kg did not prolong the template bleeding time. In the dog eversion graft model, infusion of 100 μg/kg of G4120 over 60 min did not fully inhibit platelet-mediated thrombotic occlusion but was associated with inhibition of ADP-induccd ex vivo platelet aggregation and with prolongation of the template bleeding time from 1.3 ± 0.4 to 12 ± 2 min. Infusion of 300 μg/kg of TP9201 over 60 min completely prevented thrombotic occlusion, inhibited ex vivo platelet aggregation, but was not associated with prolongation of the template bleeding time.TP9201, unlike G4120, inhibits in vivo platelet-mediated thrombus formation without associated prolongation of the template bleeding time.

Significance of Platelet β-Adrenoceptors for Platelet Responses In Vivo and In Vitro

1992 ◽  
Vol 68 (06) ◽  
pp. 687-693 ◽  
Author(s):  
P T Larsson ◽  
N H Wallén ◽  
A Martinsson ◽  
N Egberg ◽  
P Hjemdahl
Keyword(s):  
Ex Vivo ◽  
High Dose ◽  
Platelet Aggregability ◽  
Adrenoceptor Agonist ◽  
Dose Infusion ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Antigen

SummaryThe significance of platelet β-adrenoceptors for platelet responses to adrenergic stimuli in vivo and in vitro was studied in healthy volunteers. Low dose infusion of the β-adrenoceptor agonist isoprenaline decreased platelet aggregability in vivo as measured by ex vivo filtragometry. Infusion of adrenaline, a mixed α- and β-adrenoceptor agonist, increased platelet aggregability in vivo markedly, as measured by ex vivo filtragometry and plasma β-thromboglobulin levels. Adrenaline levels were 3–4 nM in venous plasma during infusion. Both adrenaline and high dose isoprenaline elevated plasma von Willebrand factor antigen levels β-Blockade by propranolol did not alter our measures of platelet aggregability at rest or during adrenaline infusions, but inhibited adrenaline-induced increases in vWf:ag. In a model using filtragometry to assess platelet aggregability in whole blood in vitro, propranolol enhanced the proaggregatory actions of 5 nM, but not of 10 nM adrenaline. The present data suggest that β-adrenoceptor stimulation can inhibit platelet function in vivo but that effects of adrenaline at high physiological concentrations are dominated by an α-adrenoceptor mediated proaggregatory action.

In Vivo Effect of Suloctidil as an Antiplatelet Agent

1979 ◽  
Vol 41 (03) ◽  
pp. 465-474 ◽  
Author(s):  
Marcia R Stelzer ◽  
Thomas S Burns ◽  
Robert N Saunders
Keyword(s):  
Ex Vivo ◽  
Antiplatelet Agent ◽  
Ratio Method ◽  
Platelet Aggregate ◽  
Permanent Effect ◽  
Platelet Aggregates ◽  
5 Ht Uptake ◽  
High Doses

SummaryThe relationship between the effects of suloctidil in vivo as an antiplatelet agent and in vitro as a modifier of platelet serotonin (5-HT) parameters was investigated. Suloctidil was found to be effective in reducing platelet aggregates formation in the retired breeder rat as determined using the platelet aggregate ratio method (PAR) with an ED50 of 16.1 mg/kg 24 hours post administration. In contrast to the hypothesis that 5-HT depletion is involved in the anti-aggregatory mechanism of suloctidil, no correlation was found between platelet 5- HT content and this antiplatelet activity. Reduction of platelet 5-HT content required multiple injections of high doses (100 mg/kg/day) of suloctidil. Suloctidil administration for 8 days at 100 mg/kg/day, which lowered platelet 5-HT content by 50%, resulted in no permanent effect on ex vivo platelet 5-HT uptake or thrombin-induced release, nor alteration in the plasma 5-HT level. However, these platelets exhibited a short-lived, significant increase in percent leakage of 5-HT after 30 minutes of incubation. Therefore, suloctidil treatment at high doses may with time result in platelet 5-HT depletion, however this effect is probably not related to the primary anti-aggregatory activity of the drug.

Studies on the Haemostatic Defect in a Complicated Syndrome

1995 ◽  
Vol 74 (05) ◽  
pp. 1244-1251 ◽  
Author(s):  
H Stormorken ◽  
H Holmsen ◽  
R Sund ◽  
K S Sakariassen ◽  
T Hovig ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Bleeding Tendency ◽  
Clot Retraction ◽  
Abnormal Finding ◽  
Shear Rates ◽  
Perfusion Chamber ◽  
Coagulant Activity ◽  
5 Ht Uptake ◽  
And Storage

SummaryThe Stormorken syndrome is a multifacetted syndrome including a bleeding tendency. No deviations were found in the coagulation- or fibrinolytic systems. Platelet number was low normal, and size abnormal, whereas EM findings were unremarkable. Survival time was half normal. Clot retraction was initially rapid, but clearly decreased, whereas prothrombin consumption was also initially rapid, but complete. Membrane GP’s were normal, so was AA metabolism, PI-cycle, granule storage and secretion, and c-AMP function, whereas 5-HT uptake and storage was decreased. Optical platelet aggregation was low normal with all physiological agonists. The only clearly abnormal finding was that coagulant activity was present on non stimulated platelets at the same level as kaolin-stimulated normal platelets. This indicated a platelet abnormality which should lead to a thrombogenic, not to a haemorrhagic trait. This paradox may have its origin in rheology, because when challenged with in vivo shear rates in an ex vivo perfusion chamber, platelet cohesion was abnormally low. Further studies to better delineate the membrane abnormality are underway.

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