Spleen Gives Heart a Leg Up

A study in the journal Science shows that the spleen has a previously unrecognized function, as a large reservoir of infection-fighting monocytes that come into play in heart damage. Cynthia Graber reports

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Poor old spleen, it never got the recognition it deserved. Until now. Scientists had known that the spleen is part of our immune systems. But it was considered expendable, an organ we could live fine without, if we had to, nothing crucial. Now researchers in Boston say that the spleen actually helps mend damaged hearts. The study was published in the July 31st issue of the journal Science.

They’ve shown that the spleen is what they call a critical reservoir of monocytes. Those are cells that scientists had previously thought were only found in bone marrow and blood that help fight infection. Scientists discovered these spleen-based monocytes by accident. They were investigating heart damage and found more monocytes at the site of the damage than should have been in the entire circulatory system. Upon investigation, they found the reservoir in the spleen.


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After a heart attack, those monocytes surge out of the spleen. When they reach the heart, they fight infection and are critically important in helping mend the heart tissue. The researchers now want to find out if there are other conditions where spleen-based monocytes are critical. Finally, the Rodney Dangerfield of organs gets some respect.

—Cynthia Graber

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