This could liberate future researchers from relying on embryonic tissue, which can be more difficult to acquire.
“NatureNews,” the news alert website for the journal Nature, has a news report (registration required) on a study published in the December 6 issue of the journal by researchers from Bonn, New York, Rhode Island, and Pennsylvania on regenerating heart muscle.
It is known that (in mice and assumed in humans) that embryonic heart stem cells or precursor cells (they’re a bit more specialized than most of the “stem cells” we’ve been hearing about – cardiac myocytes (eCMs) and skeletal myocytes (“SMs”) will bind to damaged areas of the heart and promote healing and division. However, the SMs have a much higher risk of irregular heartbeats called “ventricular tachycardia.” (The “VTach” that causes most sudden deaths after heart attacks in real life and the dramatic scenes on TV.) Even though some people do have better heart function after treatment with their own SMs (from bone marrow or skeletal muscle), 15% of them die of VTach within 3 years.
The researchers found that the eCM’s “coupled physically” to the damaged cells in the heart and exchanged electrical signals with the surrounding heart cells, so that they contracted in the proper rhythm.
The scientists (rather than deciding to pursue only eCM therapy) wanted to know why the SMs didn’t do as well as eCM when it came to producing the correct rhythm. They discovered that the eCMs had more Cx43 than skeletal muscle. Mice were developed with gene therapy (using viral vectors to insert genes, a common technique used to create “gene mod” mice for research) so that the SMs of the mice express more Cx43 in skeletal muscle than normal. The mice hearts that received the modified SM’s from these mice, when cultured and then injected into damaged hearts of other mice, did as well as the hearts that received eCMs.
The science is fascinating, but the irony of the report coming this week is pretty interesting, too. The author of the NatureNews report is truly unbiased or evidently didn’t get the memo from the reactionary scientists this week.
(In case you’re wondering, I don’t get a memo from anyone other than the reactionaries’ own blogs, and statements to the press.)