Regeneración de partes?

Estaba leyendo un articulo llamado "Humans can regrow fingers?" , cuentan como un señor perdió la punta de su dedo y se le regenero completamente con uña y todo!!!. Vean un poco.

February 20, 2007 When a hobby-store owner in Cincinnati sliced off his fingertip in 2005 while showing a customer why the motor on his model plane was dangerous, he went to the emergency room without the missing tip. He couldn't find it anywhere. The doctor bandaged the wound and recommended a skin graft to cover the top of his right-middle stub for cosmetic purposes, since nothing could be done to rebuild the finger. Months later, he had regrown it, tissue, nerves, skin, fingernail and all. This particular hobbyist happened to have a brother in the tissue-regeneration business, who told him to forego the skin graft and instead apply a powdered extract taken from pig's bladder to the raw finger tip. The extract, called extracellular matrix, lays the framework that cells use to generate any given body part. It's like a cellular scaffolding, and all animals have it. It holds the signals that direct cells to divide, differentiate and build themselves into a specific form. Extracellular matrix is not cellular -- it's a component of body tissue that functions outside of the body's cells (thus the "extracellular" designation"). It's made up mostly of collagen, a type of protein. So extracellular matrix extracted from the bladder of a pig does not actually have any of the pig's cells in it. In human fetuses, the substance works in concert with stem cells to grow and regrow everything from heart aortas to toes. Fetuses can regrow almost anything that gets damaged while in the womb.

Mas