In contrast to an obsolete notion that erythrocytes, or red blood cells (
The advancement of microfluidic technology has facilitated the simulation of physiological conditions of the microcirculation, such as oxygen tension, fluid flow, and shear stress in these devices. Here, we present a micro‐gas exchanger integrated with microfluidics to study
We simulated a range of physiological conditions and explored
Significant heterogeneity in
The approach presented here enabled the control of oxygen tension in blood during microscale flow and the quantification of
- Award ID(s):
- 1552782
- NSF-PAR ID:
- 10027485
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Microcirculation
- Volume:
- 24
- Issue:
- 5
- ISSN:
- 1073-9688
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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RBC s), play a passive and minor role in haemostasis and thrombosis, over the past decades there has been increasing evidence thatRBC s have biologically and clinically important functions in blood clotting and its disorders. This review summarizes the main mechanisms that underlie the involvement ofRBC s in haemostasis and thrombosisin vivo , such as rheological effects on blood viscosity and platelet margination, aggregation and deformability ofRBC s; direct adhesion and indirect biochemical interactions with endothelial cells and platelets. The ability of stored and pathologically alteredRBC s to generate thrombin through exposure of phosphatidylserine has been emphasized. The procoagulant and prothrombotic potential ofRBC ‐derived microparticles transfused with storedRBC s or formed in various pathological conditions associated with haemolysis has been described along with prothrombotic effects of free haemoglobin and haem. Binding of fibrinogen or fibrin toRBC s may influence their effects on fibrin network structure, clot mechanical properties and fibrinolytic resistance. Recent data on platelet‐driven clot contraction show thatRBC s compressed by platelets pulling on fibrin form a tightly packed array of polyhedral erythrocytes, or polyhedrocytes, which comprises a nearly impermeable barrier important for haemostasis and wound healing.RBC s may perform dual roles, both helping to stem bleeding but at the same time contributing to thrombosis in a variety of ways. -
Abstract Sickle cell disease (SCD) is a recessive genetic blood disorder exhibiting abnormal blood rheology. Polymerization of sickle hemoglobin, due to a point mutation in the
β‐globin gene of hemoglobin, results in aberrantly adhesive and stiff red blood cells (RBCs). Hemolysis, abnormal RBC adhesion, and abnormal blood rheology together impair endothelial health in people with SCD, which leads to cumulative systemic complications. Here, we describe a microfluidic assay combined with a micro particle image velocimetry technique for the integrated in vitro assessment of whole blood viscosity (WBV) and RBC adhesion. We examined WBV and RBC adhesion to laminin (LN) in microscale flow in whole blood samples from 53 individuals with no hemoglobinopathies (HbAA, N = 10), hemoglobin SC disease (HbSC, N = 14), or homozygous SCD (HbSS, N = 29) with mean WBV of 4.50 cP, 4.08 cP, and 3.73 cP, respectively. We found that WBV correlated with RBC count and hematocrit in subjects with HbSC or HbSS. There was a significant inverse association between WBV and RBC adhesion under both normoxic and physiologically hypoxic (SpO2of 83%) tests, in which lower WBV associated with higher RBC adhesion to LN in subjects with HbSS. Low WBV has been found by others to associate with endothelial activation. Altered WBV and abnormal RBC adhesion may synergistically contribute to the endothelial damage and cumulative pathophysiology of SCD. These findings suggest that WBV and RBC adhesion may serve as clinically relevant biomarkers and endpoints in assessing emerging targeted and curative therapies in SCD. -
Abstract Objective To characterize ossified bone marrow blood vessels and confirm the presence of ossified particles (
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