A PACEMAKER MADE FROM LIVING CELLS:

Cowan’s team, including first author Yeong-Hoon Choi in Children’s Department of Cardiac Surgery, obtained skeletal muscle from rats and isolated muscle precursor cells called myoblasts. They “seeded” the myoblasts onto a flexible scaffolding material made of collagen, creating a 3-dimensional bit of living tissue that could be surgically implanted in the heart.

The cells distributed themselves evenly in the tissue and oriented themselves in the same direction. Tested in the laboratory, the engineered tissue started beating when stimulated electrically, and its muscle cells produced proteins called connexins that channel ions from cell to cell, connecting the cells electrically.

When the engineered tissue was implanted into rats, between the right atrium and right ventricle, the implanted cells integrated with the surrounding heart tissue and electrically coupled to neighboring heart cells. Optical mapping of the heart showed that in nearly a third of the hearts, the engineered tissue had established an electrical conduction pathway, which disappeared when the implants were destroyed. The implants remained functional through the animals’ lifespan (about 3 years).

This is cool, though it’s more a pacemaker-substitute than a pacemaker, I think. (Via Slashdot).

UPDATE: Reader Chuck Pelto emails to note that the above is actually better than a pacemaker, since it fixes the problem. He also asks how Don Ho is doing after his Thai stem-cell operation. Pretty well, according to this report:

In December, Ho flew to Thailand for treatment of a deteriorating heart muscle and abnormal heart rhythm. The operation was described as a last resort for the entertainer after doctors here said there was nothing more that could be done to treat him.

Ho was back in January doing two shows a week at the Ohana Waikiki Beachcomber Hotel.

The experimental stem cell procedure costs between $25,000 and $30,000, but has not been approved in the United States and isn’t covered by insurance. . . .

Since last May, the Bangkok doctors have performed the procedure on 54 patients, mostly Americans.

“There is some light for the people who don’t have any other option left and have severe end-stage heart failure,” said Arom, who worked more than 30 years on the Mainland.

The main concern of American doctors is whether stem cells survive and actually contribute to improved heart performance.

While the procedure has been proved to work on rats, no one knows its effect on humans, said Livingston Wong, who retired from well-known transplant practice Surgical Associates in Honolulu.

I guess we’ll find out. I’d like to see this get more rigorous evaluation, and I certainly hope it turns out to work as well as advertised. Note that these are autologous stem cells, not embryonic stem cells — it’s done overseas because normal U.S. regulatory barriers are too high, not because of any stem-cell-specific ban.