Nav: Home

Quantitative assessment of dynamic deformability and adhesion of red blood cells possible

March 01, 2016

A team of researchers from the Case Western Reserve University (CWRU) in Cleveland, OH have developed a versatile microfluidic platform integrated with a cell dimensioning algorithm for quantitative assessment of dynamic deformability and adhesion of RBCs in controlled microphysiological flow. Accurate measurement of RBC deformability and adhesion, which are the two key biophysical factors of vaso-occlusion in SCD, holds great potential as a marker for evaluation of disease progression, gaining insight into disease pathophysiology, and development of novel therapeutics. Although various approaches have been utilized for measurement of deformability and adhesion of RBCs, such as atomic force microscopy and optical tweezers, none of these methods could be conducted at physiological conditions using whole blood in a clinically relevant way. The developed microfluidic system can probe deformation characteristics of RBCs at the single cell level, as well as reflecting microvasculature adhesion response in whole SCD patient blood samples.

"Microfluidic techniques allow incorporation of physiological flow conditions, as well as biologically relevant adhesion surfaces in a closed setting, which better mimic the natural physiological environment of the RBCs in blood flow. The microfluidic system developed here has the potential to be used in a high-throughput manner with an integrated automated image processing algorithm for measurement of RBC deformability and adhesion in patients' blood." says Professor Umut Gurkan, Ph.D., of the Case Western Reserve University and Principal Investigator on the paper.

Red blood cells (RBCs) undergo dynamic reversible deformations in blood circulation and respond to fluid shear stresses rapidly with time constants in the range of 100 milliseconds. However, RBCs lose their ability to deform dynamically with maladies such as diabetes, malaria infection, hereditary spherocytosis, and various mutations affecting globin genes, such as the sickle cell disease (SCD). SCD is the first recog-nized molecular disease, which was identified as a hemoglobin disorder more than sixty years ago. In the roots of the disease is a point mutation in the 6th chain of the hemoglobin gene, which results in abnormal polymerization of hemoglobin molecules inside the RBCs. Formation of polymerized hemoglobin fibers disrupts cell morphology, decreases RBC deformability (increase in stiffness), and changes membrane adhesive properties. Abnormal adhesion and decreased deformability of RBCs are the main causes of blood vessel occlusion (vaso-occlusion) in SCD. Vaso-occlusion is the hallmark of the disease and it has been associated with severe pain, crises, wide-spread organ damage, and early mortality.

Molecular basis of the SCD have been investigated extensively. However, there are limited number of studies focusing on the biophysical factors in tandem, such as the deformability and the adhesion of RBCs, which are highly dynamic phenomena. Even though RBC deformability has been associated with vaso-occlusion in SCD, we have limited knowledge on dynamic deformation characteristics of RBCs adhered to endothelium associated proteins in microphysiological fluid flow conditions. While various approaches have been utilized for the measurement of RBC deformability, including optical tweezers, micropipette aspiration, atomic force microscopy (AFM), and microfluidics. Even though optical tweezers, micropipette aspiration, and AFM analyses have enabled sensitive and controlled measurement of RBC mechanical properties, these methods are typically performed in open environments without fluid flow.

The developed microfluidic platform by the CWRU researchers can probe dynamic deformation behavior of adhered RBCs under physiological flow conditions at the single cell level. To assess dynamic deformability of RBCs, the researchers introduced a new parameter: dynamic deformability index (DDI), which they defined as the time dependent change of the cell's aspect ratio. "Using this microfluidic system, we ana-lyzed dynamic deformability and adhesion of sickle RBCs at physiological and above physiological flow shear stresses. We report for the first time on the subpopulations of RBCs in terms of dynamic deformation characteristics in SCD: deformable and non-deformable RBCs. Furthermore, we analyzed adhesion of non-deformable RBCs, in comparison to deformable RBCs, quantitatively at physiological and above physiological flow shear stresses in blood samples obtained from SCD patients. We observed significantly greater number of adhered non-deformable sickle RBCs than deformable sickle RBCs at flow shear stresses well-above the physiological range, suggesting an interplay between dynamic deformability and increased adhesion of RBCs in vaso-occlusive events." says Yunus Alapan, Ph.D. candidate, the lead author on this paper.

A unified investigation of adhesion and deformability properties of RBCs may have significant implications for understanding vaso-occlusion events and for phenotyping disease pathophysiology. Studying dynamic deformation of cells may have implications in other multi-system diseases such as β-thalassemia, diabetes mellitus, hereditary spherocytosis, polycythemia vera, and malaria. The team from CWRU is now working to further characterize deformability and adhesion of RBCs in greater number of SCD patients to analyze their associations with clinical phenotypes and complications. This adaptable technology may give important biophysical insights into disease pathophysiology when widely applied in SCD. Further-more, the developed microfluidic platform has the potential to be used as an in vitro assay for monitoring disease activity, at baseline and during clinical flux after treatment, during painful episodes, and in association with long-term complications.
Co-authors of the TECHNOLOGY paper are Yumi Matsuyama from Mechanical and Aerospace Engineering Department at CWRU, and Jane Little, M.D., from University Hospitals and School of Medicine at CWRU.

This work was funded by the Doris Duke Charitable Foundation under award number 2013126.

Corresponding author for this study in TECHNOLOGY is Professor Umut Gurkan, Ph.D.,

World Scientific

Related Sickle Cell Disease Articles:

Cannabis shows potential for mitigating sickle cell disease pain
Cannabis appears to be a safe and potentially effective treatment for the chronic pain that afflicts people with sickle cell disease, according to a new clinical trial co-led by University of California, Irvine researcher Kalpna Gupta and Dr.
Exploring mechanisms of resistance to HIV in people with sickle cell disease
A new analysis supports prior reports that people with sickle cell disease have lower rates of human immunodeficiency virus (HIV) infection, but follow-up cell studies did not reveal a mechanism to explain the reduced risk.
Light-to-moderate exercise may bring benefits for sickle cell disease
While exercise offers benefits for a wide range of health conditions, it has historically been considered too dangerous for people living with sickle cell disease (SCD).
Social determinant screening useful for families with pediatric sickle cell disease
Individuals with sickle cell disease (SCD) face the burdens of chronic illness and often racial disparities, both of which may increase vulnerability to adverse social determinants of health (SDoH).
Uncovering new therapeutic targets for airway inflammation in sickle cell disease
A new study by De, Agrawal, Morrone et al, challenges the common notion that airway in-flammation in Sickle Cell Disease (SCD) is secondary to asthma, even though the two disor-ders often coexist.
Researchers develop new method to rapidly, reliably monitor sickle cell disease
Researchers have developed a rapid and reliable new method to continuously monitor sickle cell disease using a microfluidics-based electrical impedance sensor.
Sickle cell disease needs more attention
Article signed by researchers affiliated with institutions in the US, UK, Ghana and Brazil highlights recent progress in diagnosis and treatment but warns that more screening of newborns is needed.
New genetic weapons challenge sickle cell disease
Researchers advancing gene-editing techniques to help patients with sickle cell disease discover an unexpected boost in fetal hemoglobin production, which mutes the effect of the disease.
Routine sickle cell disease screening among migrants may help save lives
Hematologists are zeroing in on the escalating humanitarian crisis in southern Europe by assessing the burden of blood disorders among refugees and identifying strategies to facilitate more timely identification and treatment of refugees with sickle cell disease (SCD).
Most precise measurements of sickle cell disease building blocks could lead to new treatments
In a breakthrough study of sickle cell disease, biomedical engineers in the University of Minnesota College of Science and Engineering have revealed that the building blocks of the disease are much less efficient at organizing than previously thought.
More Sickle Cell Disease News and Sickle Cell Disease Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at     You can read The Transition Integrity Project's report here.