An Unexpected New Lung Function Has Been Found - They Make Bloodhttp://www.sciencealert.com/an-unexpected-new-lung-function-has-been-discovered-and-it-could-disrupt-decades-of-scientific-thought
Researchers have discovered that the lungs play a far more complex role in mammalian bodies than we thought, with new evidence revealing that they don't just facilitate respiration - they also play a key role in blood production. ( Read more... )
While the lungs have been known to produce a limited amount of platelets - platelet-forming cells called megakaryocytes have been identified in the lungs before - scientists have long assumed that most of the cells responsible for blood production are kept inside the bone marrow.
Here, a process called haematopoiesis was thought to churn out oxygen-laden red blood cells, infection-fighting white blood cells, and platelets - blood components required for the clotting that halts bleeding.
But scientists have now watched megakaryocytes functioning from within the lung tissue to produce not a few, but most of the body's platelets.
So how did we miss such a crucial biological process this whole time?
The discovery was made possible by a new type of technology based on two-photon intravital imaging - a similar technique to one used by a separate team this week to discover a previously unidentified function of the brain's cerebellum.
The process involves inserting a substance called green fluorescent protein (GFP) into the mouse genome - a protein that's naturally produced by bioluminescent animals such as jellyfish, and is harmless to living cells.
The mouse platelets started to emit bright green fluorescence as they circulated around the body in real time, allowing the team to trace their paths like never before.
They noticed a surprisingly large population of platelet-producing megakaryocytes inside the lung tissue, which initially didn't make much sense, seeing as they're usually associated with bone marrow.
"When we discovered this massive population of megakaryocytes that appeared to be living in the lung, we realised we had to follow this up," says one of the team, Emma Lefrançais.
They found that this huge supply of megakaryocytes is actually producing more than 10 million platelets per hour in the lungs of mice, which means at least half of the body's total platelet production is occurring in the lungs.
Here's what it looks like:( Read more... )