July 31, 2008

Researchers Test New Source for Blood Platelets

THURSDAY, July 31 (HealthDay News) -- A new and potentially better source of platelets (clot-forming blood cells) for transfusion has been identified by Japanese researchers.

Platelets can drop to dangerously low levels in people with anemia and in cancer patients undergoing chemotherapy. To boost platelet levels, doctors filter platelets from donated blood. However, this approach may increase the risk of transmitting blood infections and cause other side effects in patients who require frequent transfusions, according to background information in the study.

To avoid these problems, researchers have been trying to find ways to generate platelets from embryonic stem cell lines. However, these stem cells also give rise to other types of cells, which can quickly outnumber the platelets. The Japanese team solved this problem by starting with a stem cell population already committed to becoming platelets.

The researchers also noted that platelets derived from stem cells often fail to form clots properly, a problem that can be caused by the presence of enzymes that shear adhesive proteins from the surface of platelets, which prevents them from sticking to one another or to blood vessel walls.

The Japanese scientists found that blocking these enzymes restored platelet function when the cells were placed in mice. The researchers plan to test whether this same approach will work in people.

The study was published in the current issue of the Journal of Experimental Medicine.

More information

The MedlinePlus Medical Encyclopedia has more about low platelet count.

-- Robert Preidt
SOURCE: Journal of Experimental Medicine, news release, July 28, 2008
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