Using video microscopy in the living mouse lung, UC San Francisco scientists have revealed that the lungs play a previously unrecognized role in blood production. As reported online March 22, 2017, in Nature, the researchers found that the lungs produced more than half of the platelets ? blood components required for the clotting that stanches bleeding ? in the mouse circulation.

In another surprise finding, the scientists also identified a previously unknown pool of blood stem cells capable of restoring blood production when the stem cells of the bone marrow, previously thought to be the principal site of blood production, are depleted.

?This finding definitely suggests a more sophisticated view of the lungs ? that they?re not just for respiration but also a key partner in formation of crucial aspects of the blood,? said pulmonologist Mark R. Looney, MD, a professor of medicine and of laboratory medicine at UCSF and the new paper?s senior author. ?What we?ve observed here in mice strongly suggests the lung may play a key role in blood formation in humans as well.?

The findings could have major implications for understanding human diseases in which patients suffer from low platelet counts, or thrombocytopenia, which afflicts millions of people and increases the risk of dangerous uncontrolled bleeding. The findings also raise questions about how blood stem cells residing in the lungs may affect the recipients of lung transplants.

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http://www.ucsf.edu/news/2017/03/406...s-making-blood