scholarly journals Phagocytic Uptake of Particles by Immune cells Under Flow Conditions

2021 ◽  
Author(s):  
Megha Srinivas ◽  
Preeti Sharma ◽  
Siddharth Jhunjhunwala
Keyword(s):  
Immune Cells ◽  
Cell Type ◽  
Pulsatile Blood Flow ◽  
Flow Conditions ◽  
Circulating Cells ◽  
Type Particle ◽  
Particulate Delivery ◽  
Static Conditions ◽  
Phagocytic Uptake

Particles injected intravenously are thought to be cleared by macrophages residing in the liver and spleen, but they also encounter circulating immune cells. It remains to be determined if the circulating cells can take up particles while flowing in the blood. Here, we use an in vitro peristaltic pump setup that mimics pulsatile blood flow to establish if immune cells take up particles under constant fluidic flow. Our results show that the immune cells do phagocytose under flow conditions, and the uptake depends on the cell type, particle size, and flow rate. We demonstrate that cell lines representing myeloid cells, and primary neutrophils and monocytes are similar or better at taking up sub-micrometer-sized particles under flow compared to static conditions. Experiments with whole blood show that even under the crowding effects of red blood cells, neutrophils and monocytes take up particles while flowing. These data suggest that therapeutics may be delivered to circulating immune cells using particulate delivery systems.

Gas Transport in Serpentine Microporous Tubes Under Steady and Pulsatile Blood Flow Conditions

1991 ◽  
Vol 113 (2) ◽  
pp. 223-229 ◽  
Author(s):  
Kazuo Tanishita ◽  
Masanobu Ujihira ◽  
Akihisa Watabe ◽  
Kunio Nakano ◽  
Peter D. Richardson ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Transfer ◽  
Ex Vivo ◽  
Radius Of Curvature ◽  
Gas Transfer ◽  
Pulsatile Blood Flow ◽  
Flow Conditions ◽  
Wide Range ◽  
Exchange Unit

A serpentine gas exchange unit was built with cylindrical tubular microporous membranes featuring periodic arcs with a fixed curvature ratio (ratio of tube radius to radius of curvature) of 1/14 and circular angles between 30 and 360 deg. Oxygen transfer was measured under steady and pulsatile blood flow conditions in vitro and ex vivo to assess the design features which most effectively augment gas transfer. Under steady blood flow conditions, oxygen transfer increased with circular angles beyond 70 deg. Under pulsatile conditions, a wide range of geometrical and fluid mechanical parameters could be combined to enhance gas transfer performance, which eventually depended upon the secondary Reynolds number and the Womersley parameter.

scholarly journals Defective Neutrophil Transendothelial Migration and Lateral Motility in ARPC1B Deficiency Under Flow Conditions

2021 ◽  
Vol 12 ◽  
Author(s):  
Lanette Kempers ◽  
Evelien G. G. Sprenkeler ◽  
Abraham C. I. van Steen ◽  
Jaap D. van Buul ◽  
Taco W. Kuijpers
Keyword(s):  
Actin Polymerization ◽  
Collagen Matrix ◽  
Flow Conditions ◽  
Tnf Α ◽  
A Subunit ◽  
3D Collagen ◽  
And Migration ◽  
Static Conditions ◽  
Cellular Immune

The actin-related protein (ARP) 2/3 complex, essential for organizing and nucleating branched actin filaments, is required for several cellular immune processes, including cell migration and granule exocytosis. Recently, genetic defects in ARPC1B, a subunit of this complex, were reported. Mutations in ARPC1B result in defective ARP2/3-dependent actin filament branching, leading to a combined immunodeficiency with severe inflammation. In vitro, neutrophils of these patients showed defects in actin polymerization and chemotaxis, whereas adhesion was not altered under static conditions. Here we show that under physiological flow conditions human ARPC1B-deficient neutrophils were able to transmigrate through TNF-α-pre-activated endothelial cells with a decreased efficiency and, once transmigrated, showed definite impairment in subendothelial crawling. Furthermore, severe locomotion and migration defects were observed in a 3D collagen matrix and a perfusable vessel-on-a-chip model. These data illustrate that neutrophils employ ARP2/3-independent steps of adhesion strengthening for transmigration but rely on ARP2/3-dependent modes of migration in a more complex multidimensional environment.

scholarly journals Effect of Pulse Frequency on the Osteogenic Differentiation of Mesenchymal Stem Cells in a Pulsatile Perfusion Bioreactor

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
Katherine D. Kavlock ◽  
Aaron S. Goldstein
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Three Dimensional ◽  
Intermediate Frequency ◽  
Osteoblastic Differentiation ◽  
Protein Accumulation ◽  
Flow Conditions ◽  
Alp Activity ◽  
Static Conditions

Perfusion bioreactors are a promising in vitro strategy to engineer bone tissue because they supply needed oxygen and nutrients and apply an osteoinductive mechanical stimulus to osteoblasts within large porous three-dimensional scaffolds. Model two-dimensional studies have shown that dynamic flow conditions (e.g., pulsatile oscillatory waveforms) elicit an enhanced mechanotransductive response and elevated expression of osteoblastic proteins relative to steady flow. However, dynamic perfusion of three-dimensional scaffolds has been primarily examined in short term cultures to probe for early markers of mechanotransduction. Therefore, the objective of this study was to investigate the effect of extended dynamic perfusion culture on osteoblastic differentiation of primary mesenchymal stem cells (MSCs). To accomplish this, rat bone marrow-derived MSCs were seeded into porous foam scaffolds and cultured for 15 days in osteogenic medium under pulsatile regimens of 0.083, 0.050, and 0.017 Hz. Concurrently, MSCs seeded in scaffolds were also maintained under static conditions or cultured under steady perfusion. Analysis of the cells after 15 days of culture indicated that alkaline phosphatase (ALP) activity, mRNA expression of osteopontin (OPN), and accumulation of OPN and prostaglandin E2 were enhanced for all four perfusion conditions relative to static culture. ALP activity, OPN and OC mRNA, and OPN protein accumulation were slightly higher for the intermediate frequency (0.05 Hz) as compared with the other flow conditions, but the differences were not statistically significant. Nevertheless, these results demonstrate that dynamic perfusion of MSCs may be a useful strategy for stimulating osteoblastic differentiation in vitro.

scholarly journals A surface acoustic wave-driven micropump for particle uptake investigation under physiological flow conditions in very small volumes

2015 ◽  
Vol 6 ◽  
pp. 414-419 ◽  
Author(s):  
Florian G Strobl ◽  
Dominik Breyer ◽  
Phillip Link ◽  
Adriano A Torrano ◽  
Christoph Bräuchle ◽  
...  
Keyword(s):  
Cellular Uptake ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Fluid Motion ◽  
Flow Profile ◽  
Flow Conditions ◽  
Particle Uptake ◽  
Physiological Flow ◽  
Static Conditions

Static conditions represent an important shortcoming of many in vitro experiments on the cellular uptake of nanoparticles. Here, we present a versatile microfluidic device based on acoustic streaming induced by surface acoustic waves (SAWs). The device offers a convenient method for introducing fluid motion in standard cell culture chambers and for mimicking capillary blood flow. We show that shear rates over the whole physiological range in sample volumes as small as 200 μL can be achieved. A precise characterization method for the induced flow profile is presented and the influence of flow on the uptake of Pt-decorated CeO2 particles by endothelial cells (HMEC-1) is demonstrated. Under physiological flow conditions the particle uptake rates for this system are significantly lower than at low shear conditions. This underlines the vital importance of the fluidic environment for cellular uptake mechanisms.

Simulation of Pulsatile Blood Flow Through a Flexible Cannula

2008 ◽  
Author(s):  
Scott C. Corbett ◽  
Ahmet U. Coskun ◽  
Hamid N-Hashemi
Keyword(s):  
Blood Flow ◽  
Survival Rates ◽  
Rigid Wall ◽  
Shear Stresses ◽  
Pulsatile Blood Flow ◽  
Flow Conditions ◽  
Access Methods ◽  
Catheter Tip ◽  
Flexible Wall

Implantable devices in direct contact with flowing blood are currently being used to treat many medical conditions; however, thromboembolism, blood damage and the attendant risk for ischemic stroke remains a major impediment. Specifically, vascular access methods, performed by the insertion of cannulae into vessels, may give rise to non-physiological pressure variations and shear stresses. To date, the hydrodynamic behavior of cannulae has been evaluated by comparing their pressure loss-flow rate relationships, as obtained from in vitro experiments. Numerical studies have evaluated cannulae as rigid wall vessels with steady flow conditions [1]. Various catheter tip styles have been compared [2], and the fluid dynamics of arterial cannulae inserted in the aortic arch have been investigated [3]. Evaluation of shear stresses within a flexible wall cannula under pulsatile blood flow conditions is discussed herein. We anticipate that considerations for pulsating blood flow and flexible device walls will indicate that anticoagulation requirements can be minimized and device related complications can be decreased, thus increasing patient survival rates.

Potential role of activated platelets in homing of human endothelial progenitor cells to subendothelial matrix

2006 ◽  
Vol 96 (10) ◽  
pp. 498-504 ◽  
Author(s):  
Eli Lev ◽  
Zeev Estrov ◽  
Khatira Aboulfatova ◽  
David Harris ◽  
Juan Granada ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Endothelial Progenitor Cells ◽  
Vascular Injury ◽  
Tissue Injury ◽  
Platelet Rich Plasma ◽  
Flow Conditions ◽  
Endothelial Progenitor ◽  
Activated Platelets ◽  
Static Conditions

SummaryEndothelial progenitor cells (EPCs) mobilize from the bone marrow in response to tissue injury and participate in vascular repair. However, there is limited data about the homing mechanisms of EPCs to vascular injury sites. Recently animal experiments indicated that platelets playa role in recruitment of EPCs to injury sites. However, data on the possible interaction between platelets and EPCs within the human system are limited. We, therefore, examined in-vitro human platelet-EPC interaction under static and flow conditions. Human EPCs were isolated from donated buffy coats by magnetic microbeads and flow cytometry cell sorting using CD133 and VEGFR-2, respectively, as markers. Platelets were tested in the form of washed platelets, platelet rich plasma or whole blood. EPCs formed heterotypic aggregates with resting platelets under static conditions, an interaction that was greatly enhanced when platelets were activated by collagen, ADP or thrombin-activation peptide. The platelet-EPC interaction was inhibited by antibodies to P-selectin or P-selectin glycoprotein ligand-1 (PSGL-1), but not by antibodies to glycoproteins Ib-IX-V or IIb/IIIa. When perfused over activated platelets under shear stress of 2.5 dyn/cm2, EPCs tethered to platelayers and either adhered immediately or rolled a short distance before adhering. In addition, platelets promoted the colonization of adherent EPCs in culture conditions. Consistent with recent animal studies, these findings demonstrate that human EPCs interact in vitro with activated platelets under static and flow conditions, mediated through P-selectin–PSGL-1 interaction. This interaction may be a central mechanism for homing of EPCs to vascular injury sites.

Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

1982 ◽  
Vol 40 ◽  
pp. 210-211
Author(s):  
M.J. Murphy ◽  
R.R. Price ◽  
J.C. Sloman
Keyword(s):  
Cultured Cells ◽  
Human Tumor ◽  
Cell Type ◽  
Tumor Mass ◽  
Initial Cell ◽  
Cloning Assay ◽  
Human Tumor Cloning ◽  
The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

Platelet and Shear Rate Promote Tumor Cell Adhesion to Human Endothelial Extracellular Matrix - Absence of a Role for Platelet Cyclooxygenase

1989 ◽  
Vol 61 (03) ◽  
pp. 485-489 ◽  
Author(s):  
Eva Bastida ◽  
Lourdes Almirall ◽  
Antonio Ordinas
Keyword(s):  
Cell Adhesion ◽  
Shear Rate ◽  
Tumor Cell ◽  
Umbilical Vein ◽  
Blood Platelets ◽  
Flow Conditions ◽  
Tumor Cell Adhesion ◽  
Rate Dependent ◽  
Static Conditions

SummaryBlood platelets are thought to be involved in certain aspects of malignant dissemination. To study the role of platelets in tumor cell adherence to vascular endothelium we performed studies under static and flow conditions, measuring tumor cell adhesion in the absence or presence of platelets. We used highly metastatic human adenocarcinoma cells of the lung, cultured human umbilical vein endothelial cells (ECs) and extracellular matrices (ECM) prepared from confluent EC monolayers. Our results indicated that under static conditions platelets do not significantly increase tumor cell adhesion to either intact ECs or to exposed ECM. Conversely, the studies performed under flow conditions using the flat chamber perfusion system indicated that the presence of 2 × 105 pl/μl in the perfusate significantly increased the number of tumor cells adhered to ECM, and that this effect was shear rate dependent. The maximal values of tumor cell adhesion were obtained, in presence of platelets, at a shear rate of 1,300 sec-1. Furthermore, our results with ASA-treated platelets suggest that the role of platelets in enhancing tumor cell adhesion to ECM is independent of the activation of the platelet cyclooxygenase pathway.

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