Stem cells have long held the the promise of revolutionising medicine. They're taking a while to deliver on the promise, but two new studies have brought us a little closer.

One combats the life-threatening rejection disease that many bone marrow donation recipients develop ... using a different type of stem cell.

The other looks at using someone's own blood to generate a 'patch' that could replace the need for a heart transplant. What's more, a key ingredient of keeping the patch going comes from silkworms.