How white blood cells rip holes in your blood vessels—and how your blood vessels recover
White blood cells are constantly tearing holes in your blood vessel
walls. But these guardians of the immune system are doing it to protect
you: Once they ride through the bloodstream to infected tissues—where
they make antibodies and eat foreign invaders—they need a way to get
inside. Now, scientists have discovered just how they do it without
permanently damaging blood vessels, which they slip into and out of up
to 10 times each day. First, researchers added fluorescent tags to their
nuclei and to the structural fibers of blood vessel walls, which keep
out foreign particles and seal in blood, plasma, and immune cells. The
researchers then tracked the process with video-microscopy. They found
that blood vessel cells were not the ones making the openings, as
previously thought. Instead, immune cells make their own way across. By
softening their bulky nuclei and pushing them to the front edge of their
cells, white blood cells probe apart scaffolding in the blood vessel walls and squeeze through, researchers report online today in Cell Reports.
This process (seen above) snaps smaller, threadlike fibers that form
the flexible scaffolding of blood vessel walls; the cells easily repair
that breakage later as part of routine cellular maintenance. The
researchers hope to use their discovery to better understand how
metastatic cancer cells migrate into the bloodstream and spread cancer
throughout the body.
A. Barzilai et. al. Cell Reports 18, 3 (17 January 2017) © 2017 Elsevier Inc.
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