Imaging Technique Monitors Movement of White Blood Cells

Microdomains are restricted areas on the surface of the cells in which receptors and signaling molecules accumulate during cell activation. Using digital multi-channel videomicroscopy, researchers were able to view white blood cell subsets and their forming microdomains in the vascular system in real time. The investigators, from Mount Sinai School of Medicine (New York, NY, USA), published their findings in the March 2007 issue of the journal Nature Methods. The new research displays the migration and inner workings of white blood cells in the small veins and bone marrow of mice.

"Intravital microscopy [IVM] has contributed enormously to the recent mechanistic advances in leukocyte trafficking,” wrote researchers from the department of medicine's Immunobiology Center at the Mount Sinai School of Medicine and Black Family Stem Cell Institute (New York, NY, USA). "Multichannel digital fluorescence videomicropscopy vastly improves on prior intravital observations of leukocyte behavior in vivo by allowing the near-simultaneous observation of cell surface markers and microdomains.”

Researchers examined various mouse models including that of sickle cell disease, which is a common inherited blood disorder in the United States, affecting 72,000 Americans according to the U.S. National Institutes of Health (NIH). Sickle cell disease is a blood disorder that affects hemoglobin. Abnormal hemoglobin polymerizes, and red blood cells become sickle-shaped. Sickle-shaped red blood cells then clog blood vessels by sticking to white blood cells and depriving the body of needed oxygen.

Utilizing this new imaging method, red blood cells in a mouse model of sickle cell disease were shown to interact specifically with neutrophils, a subset of inflammatory white blood cells. "The ease and rapidity of this method, and the ability to combine it with current genetic labeling techniques will greatly aid investigations to elucidate in vivo inflammatory cell behavior, and provide a powerful tool for the development of therapeutics for these diseases,” according to Mount Sinai researchers.

"Sickle cell anemia was the first disease characterized at the molecular level but there is still no treatment for the acute vascular occlusions which are the hallmark of the disease,” said Mount Sinai researcher Dr. Paul S. Frenette. "In vivo imaging provides a window inside the body that allows us to see exactly which blood cells and which molecular constituents participate in the vascular occlusions. Advances in molecular imaging will likely lead to new targets for the treatment that will improve the life of patients afflicted by this terrible illness.”


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