Further laboratory tests showed that this defect disrupts the calcium pump in heart muscle cells.
Scientists have measured electrical signals from the beat of heart muscle cells and reconstructed the pattern on a computer.
They do not appear to turn into beating new heart muscle cells.
After an average of nine days, the new heart muscle cells were present in 68% of the damaged portions of the mouse hearts.
However, when poloxamer 188 was added, the cells were able to handle the stretching with no problem, in the same way as healthy heart muscle cells.
For example, in the cases of the heart-muscle cells and pancreatic cells mentioned above, dosing them with leptin keeps them healthy.
More subtly, though, the two researchers have dug up evidence that an excess of lipids damages heart-muscle cells, and even destroys pancreatic cells in rodents.
Injecting stem cells into the heart muscle carries the risk of arrhythmia, said Techung Lee, associate professor of biochemistry at the State University New York at Buffalo.
Except that researchers still couldn't prove that the heart, nerve, muscle and other cells they made from the iPS cells were exactly like the ones generated from the embryonic stem cells.
About four months after each patient's original operation, when their hearts had stabilised, Dr Bolli used a catheter to deliver 1m of the newly bred stem cells to their damaged heart muscle.
ECONOMIST: Stem cells and medicine: Repairing broken hearts | The
They overlaid muscle cells, obtained from a rat heart, on this membrane in a particular pattern.
Genzyme is itself involved in a European 300-patient phase II trial that attempts to use skeletal muscle cells from the leg to prevent heart failure.
The long-term hope is to treat patients with some sort of stem cell that could turn into beating heart muscle and replace dead cardiac tissue with fully functioning new cells.
They found that the stem cells produced growth factors that traveled to the heart, in addition to stimulating the muscle itself to make growth factors that also improved cardiac function.
He has managed to reprogram mouse connective-tissue cells so that they develop into cardiac muscle cells, and has tested them in the hearts of mice that have had heart attacks.
ECONOMIST: Stem cells and medicine: Repairing broken hearts | The
In humans they sit on nerve cells throughout the body--in the brain, heart and stomach and on skeletal muscle.
The fat cells release biochemicals that lead to inflammation, which could lead to heart attacks, strokes and joint and muscle pain.
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