[HTML][HTML] Quantitative microfluidic fluorescence microscopy to study vaso-occlusion in sickle cell disease

MA Jimenez, E Tutuncuoglu, S Barge, EM Novelli… - …, 2015 - ncbi.nlm.nih.gov
Haematologica, 2015ncbi.nlm.nih.gov
Vaso-occlusive crisis is the primary reason for emergency medical care sought by Sickle
Cell Disease (SCD) patients. 1 In vivo imaging in transgenic SCD mice has identified
molecular events that may promote vasoocclusion. 2-4 However, the relevance of these
mechanisms is not completely understood in humans. As non-invasive in vivo imaging in
humans is limited by low-resolution, 5-7 there is a need for in vitro approaches8 that can
allow visualization of single cell events in flowing human blood. Here, we introduce …
Vaso-occlusive crisis is the primary reason for emergency medical care sought by Sickle Cell Disease (SCD) patients. 1 In vivo imaging in transgenic SCD mice has identified molecular events that may promote vasoocclusion. 2-4 However, the relevance of these mechanisms is not completely understood in humans. As non-invasive in vivo imaging in humans is limited by low-resolution, 5-7 there is a need for in vitro approaches8 that can allow visualization of single cell events in flowing human blood. Here, we introduce quantitative microfluidic fluorescence microscopy (qMFM) that enables visualization of cellular interactions in human blood flowing through silicone microfluidic channels. qMFM reproduces the leukocyteendothelium adhesion cascade, starting from rolling, transition to arrest followed by crawling and platelet capture by crawling leukocytes in human blood. Remarkably, qMFM reveals that leukocyte rolling and arrest is several fold higher in SCD than in control human blood. qMFM also provides the first evidence to support the presence of slings in rolling and arresting human neutrophils. qMFM allows visualization of platelet-neutrophil interactions at single cell resolution and enables a numerical read-out of the vaso-occlusive events in the form of frequency and lifetime of interactions. This quantitative assessment renders qMFM a unique platform to study the molecular mechanism of vaso-occlusion and test the efficacy of anti-adhesion drugs in preventing vaso-occlusion.
SCD is an autosomal recessive genetic disorder that affects an estimated 100,000 Americans, and millions of people across the world. 1 Sickle Cell Anemia (SS), the most common form of SCD, leads to sickling of red blood cells (RBCs). 2 It is believed that sickle RBCs get trapped in blood vessels along with leukocytes and platelets to
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