Particle Deposition in Arteries Ex Vivo: Effects of Pressure, Flow, and Waveform

2003 ◽  
Vol 125 (3) ◽  
pp. 389-394 ◽  
Author(s):  
Naomi C. Chesler ◽  
Omyekachi C. Enyinna
Keyword(s):  
Particle Deposition ◽  
Carotid Arteries ◽  
Ex Vivo ◽  
Confocal Laser ◽  
Hydraulic Permeability ◽  
Perfusion System ◽  
Pressure Flow ◽  
Arterial Tissue ◽  
The Media ◽  
Microscopy Images

The goal of this study was to quantify the effect of hemodynamic pressure, flow and waveform perturbations on the deposition of protein-sized particles in porcine carotid arteries ex vivo. An ex vivo perfusion system was used to control the pressure and flow environment for excised arterial tissue. Confocal laser microscopy images revealed that 200 nm particles were deposited intimally and that more spheres were evident along vessels perfused under oscillatory waveform conditions than all others. Under all pressure, flow and waveform conditions, particles were excluded from the media and adventitia of the vessel wall. The steady flow data support the use of Darcy’s Law with pressure-dependent hydraulic permeability to model arterial tissue.

scholarly journals Surface modification of decellularized bovine carotid arteries with human vascular cells significantly reduces their thrombogenicity

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Eriselda Keshi ◽  
Peter Tang ◽  
Marie Weinhart ◽  
Hannah Everwien ◽  
Simon Moosburner ◽  
...  
Keyword(s):  
Surface Modification ◽  
Whole Blood ◽  
Carotid Arteries ◽  
Complete Blood Count ◽  
Ex Vivo ◽  
Vascular Grafts ◽  
Blood Perfusion ◽  
Vascular Cells ◽  
Perfusion System ◽  
Human Whole Blood

Abstract Background Since autologous veins are unavailable when needed in more than 20% of cases in vascular surgery, the production of personalized biological vascular grafts for implantation has become crucial. Surface modification of decellularized xenogeneic grafts with vascular cells to achieve physiological luminal coverage and eventually thromboresistance is an important prerequisite for implantation. However, ex vivo thrombogenicity testing remains a neglected area in the field of tissue engineering of vascular grafts due to a multifold of reasons. Methods After seeding decellularized bovine carotid arteries with human endothelial progenitor cells and umbilical cord-derived mesenchymal stem cells, luminal endothelial cell coverage (LECC) was correlated with glucose and lactate levels on the cell supernatant. Then a closed loop whole blood perfusion system was designed. Recellularized grafts with a LECC > 50% and decellularized vascular grafts were perfused with human whole blood for 2 h. Hemolysis and complete blood count evaluation was performed on an hourly basis, followed by histological and immunohistochemical analysis. Results While whole blood perfusion of decellularized grafts significantly reduced platelet counts, platelet depletion from blood resulting from binding to re-endothelialized grafts was insignificant (p = 0.7284). Moreover, macroscopic evaluation revealed thrombus formation only in the lumen of unseeded grafts and histological characterization revealed lack of CD41 positive platelets in recellularized grafts, thus confirming their thromboresistance. Conclusion In the present study we were able to demonstrate the effect of surface modification of vascular grafts in their thromboresistance in an ex vivo whole blood perfusion system. To our knowledge, this is the first study to expose engineered vascular grafts to human whole blood, recirculating at high flow rates, immediately after seeding.

scholarly journals Intimal and medial contributions to the hydraulic resistance of the arterial wall at different pressures: a combined computational and experimental study

2016 ◽  
Vol 13 (119) ◽  
pp. 20160234 ◽  
Author(s):  
K. Y. Chooi ◽  
A. Comerford ◽  
S. J. Sherwin ◽  
P. D. Weinberg
Keyword(s):  
Hydraulic Resistance ◽  
Arterial Wall ◽  
Ex Vivo ◽  
Water Flux ◽  
Applied Pressure ◽  
Volumetric Strain ◽  
Transport Processes ◽  
Constitutive Law ◽  
Hydraulic Permeability ◽  
The Media

The hydraulic resistances of the intima and media determine water flux and the advection of macromolecules into and across the arterial wall. Despite several experimental and computational studies, these transport processes and their dependence on transmural pressure remain incompletely understood. Here, we use a combination of experimental and computational methods to ascertain how the hydraulic permeability of the rat abdominal aorta depends on these two layers and how it is affected by structural rearrangement of the media under pressure. Ex vivo experiments determined the conductance of the whole wall, the thickness of the media and the geometry of medial smooth muscle cells (SMCs) and extracellular matrix (ECM). Numerical methods were used to compute water flux through the media. Intimal values were obtained by subtraction. A mechanism was identified that modulates pressure-induced changes in medial transport properties: compaction of the ECM leading to spatial reorganization of SMCs. This is summarized in an empirical constitutive law for permeability and volumetric strain. It led to the physiologically interesting observation that, as a consequence of the changes in medial microstructure, the relative contributions of the intima and media to the hydraulic resistance of the wall depend on the applied pressure; medial resistance dominated at pressures above approximately 93 mmHg in this vessel.

scholarly journals TheEx VivoHuman Placental Transfer of the Anti-HIV Nucleoside Inhibitor Abacavir and the Protease Inhibitor Amprenavir

1998 ◽  
Vol 6 (6) ◽  
pp. 244-246 ◽  
Author(s):  
R. E. Bawdon
Keyword(s):  
Protease Inhibitor ◽  
Peak Concentration ◽  
Placental Transfer ◽  
Ex Vivo ◽  
Perfusion System ◽  
Trough Serum ◽  
Immunodeficiency Virus ◽  
The Media ◽  
Trough Concentrations ◽  
Anti Hiv

Objective:The transfer of abacavir, a new nucleoside inhibitor, and amprenavir, a new protease inhibitor, used for the treatment of human immunodeficiency virus, has been studied in theex vivohuman placental model.Methods:Theex vivohuman placental model used C14antipyrine to determine the transport fraction and clearance index of these compounds at both the peak and trough serum concentrations. The clearance index accumulation and tissue concentrations were determined for each drug by high pressure liquid chromatography.Results:The clearance index of abacavir was 0.47 ± 0.19 and 0.50 ± 0.07 at peak and trough concentrations, respectively. The clearance index of amprenavir was 0.38 ± 0.09 and 0.14 ± 0.08 at peak and trough concentrations, respectively. There was no unusual accumulation of either drug in the media or tissue when the perfusion system was closed.Conclusion:Abacavir is the first nueleoside compound studied in the perfusion system with a high clearance index. The transfer of the protease inhibitor amprenavir had a clearance index 2.75 times greater than the clearance index of ritonavir at peak concentration determined in a previous study. At trough concentration the clearance index was much less than at the peak concentration. A similar result was found with ritonavir.

scholarly journals Quantitative susceptibility mapping of carotid arterial tissue ex vivo: assessing sensitivity to vessel microstructural composition

2021 ◽  
Author(s):  
Alan J. Stone ◽  
Brooke Tornifoglio ◽  
Robert D. Johnston ◽  
Karin Shmueli ◽  
Christian Kerskens ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Carotid Arteries ◽  
Ex Vivo ◽  
Enzymatic Digestion ◽  
Susceptibility Mapping ◽  
Specific Marker ◽  
Quantitative Susceptibility Mapping ◽  
Healthy Human ◽  
Significant Difference ◽  
Arterial Tissue

AbstractPurposeTo characterise microstructural contributions to the magnetic susceptibility of carotid arteries.MethodArterial vessels were scanned using high resolution quantitative susceptibility mapping (QSM) at 7T. Models of vessel degradation were generated using ex vivo porcine carotid arteries that were subjected to several different enzymatic digestion treatments that selectively removed microstructural components (smooth muscle cells, collagen and elastin). Magnetic susceptibilities measured in these tissue models were compared to those in untreated (native) porcine arteries. Magnetic susceptibility measured in native porcine carotid arteries was further compared to the susceptibility of cadaveric human carotid arteries to investigate their similarity.ResultsThe magnetic susceptibility of native porcine vessels was diamagnetic (𝒳native = −0.1820ppm), with higher susceptibilities in all models of vessel degradation (𝒳elastin degraded = −0.0163ppm; 𝒳collagen degraded = −0.1158ppm; 𝒳decellularised = −0.1379ppm; 𝒳fixed native = −0.2199ppm). Magnetic susceptibility was significantly higher in collagen degraded compared to native porcine vessels (Tukey-Kramer, p<0.01) and between elastin degraded and all other models (including native, Tukey-Kramer, p<0.001). The susceptibility of fixed healthy human arterial tissue was diamagnetic and no significant difference was found between fixed human and fixed porcine arterial tissue susceptibilities (ANOVA, p>0.05).ConclusionsMagnetic susceptibility measured using QSM is sensitive to the microstructural composition of arterial vessels – most notably to collagen. The similarity of human and porcine arterial tissue susceptibility values provides a solid basis for translational studies. As vessel microstructure becomes disrupted during the onset and progression of carotid atherosclerosis, QSM has the potential to provide a sensitive and specific marker of vessel disease.

102 Functional and metabolic phenotyping of the murine heart using an ex vivo perfusion system and 13C-substrates

2003 ◽  
Vol 2 (1) ◽  
pp. 12
Author(s):  
M KHAIRALLAH ◽  
B BOUCHARD ◽  
J MCDUFF ◽  
F LABARTHE ◽  
G DANIALOU ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Perfusion System ◽  
Metabolic Phenotyping ◽  
Ex Vivo Perfusion

The Development of Pemetrexed Diacid-Loaded Gelatin-Cloisite 30B (MMT) Nanocomposite for Improved Oral Efficacy Against Cancer: Characterization, In-Vitro and Ex-Vivo Assessment

2020 ◽  
Vol 17 (3) ◽  
pp. 246-256
Author(s):  
Kriti Soni ◽  
Ali Mujtaba ◽  
Md. Habban Akhter ◽  
Kanchan Kohli
Keyword(s):  
Drug Release ◽  
Oral Delivery ◽  
Ex Vivo ◽  
Confocal Laser ◽  
Release Mechanism ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Cloisite 30B ◽  
Ft Ir

Aim: The intention of this investigation was to develop Pemetrexed Diacid (PTX)-loaded gelatine-cloisite 30B (MMT) nanocomposite for the potential oral delivery of PTX and the in vitro, and ex vivo assessment. Background: Gelatin/Cloisite 30 B (MMT) nanocomposites were prepared by blending gelatin with MMT in aqueous solution. Methods: PTX was incorporated into the nanocomposite preparation. The nanocomposites were investigated by Fourier Transmission Infra Red Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), Scanning Electron Microscope (SEM) X-Ray Diffraction (XRD) and Confocal Laser Microscopy (CLSM). FT-IR of nanocomposite showed the disappearance of all major peaks which corroborated the formation of nanocomposites. The nanocomposites were found to have a particle size of 121.9 ± 1.85 nm and zeta potential -12.1 ± 0.63 mV. DSC thermogram of drug loaded nanocomposites indicated peak at 117.165 oC and 205.816 oC, which clearly revealed that the drug has been incorporated into the nanocomposite because of cross-linking of cloisite 30 B and gelatin in the presence of glutaraldehyde. Results: SEM images of gelatin show a network like structure which disappears in the nanocomposite. The kinetics of the drug release was studied in order to ascertain the type of release mechanism. The drug release from nanocomposites was in a controlled manner, followed by first-order kinetics and the drug release mechanism was found to be of Fickian type. Conclusion: Ex vivo gut permeation studies revealed 4 times enhancement in the permeation of drug present in the nanocomposite as compared to plain drug solution and were further affirmed by CLSM. Thus, gelatin/(MMT) nanocomposite could be promising for the oral delivery of PTX in cancer therapy and future prospects for the industrial pharmacy.

Axial Stretch Increases Cell Proliferation in Arteries in Organ Culture

2000 ◽  
Author(s):  
Hai-Chao Han ◽  
Raymond P. Vito ◽  
Kristin Michael ◽  
David N. Ku
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Organ Culture ◽  
Vascular Function ◽  
Culture System ◽  
Carotid Arteries ◽  
Ex Vivo ◽  
Axial Stretch ◽  
Organ Culture System ◽  
Physiological Flow

Abstract To study the effect of axial stretch on vascular function and wall remodeling, porcine carotid arteries were cultured under conditions of physiological flow and elevated axial stretch in an ex vivo organ culture system. Smooth muscle cell proliferation was measured by bromodeoxyuridine index. Results showed that cell proliferation was significantly increased in the highly stretched arteries when compared to the normally stretched arteries. This may indicate the feasibility of stimulating new arterial growth by stretching natural arteries.

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