In 2005, Sutherland et. al. reported that they had succeeded in creating stem-cell tissue-engineered heart valves from stem cells. These engineered heart valves were able to function satisfactorily for more than four months when transplanted into sheep. As yet, no human trials have been carried out. However, as reported in their paper published in May 31 st issue of Circulation, it is now possible to create autologous living heart valves from stem cells. The possibility of creating human heart valves and perhaps, one day, a whole functional human heart is no longer something we only see in our imagination or sci-fi movies. It may very well be reality in the not-too-distant future.
Scientists have acknowledged that hematopoietic stem cells, readily isolated from cord blood, are a delivery cell of choice in gene therapy. Gene therapy is basically the introduction of a therapeutic transgene (the new genetic material) into the patient’s body, to alter or supplement the function of an abnormal (or faulty) gene. In other words, gene therapy is a procedure whereby a normal gene is introduced into the patient’s body via a vector (delivery cells) to directly repair the faulty gene or to add new functions that were previously present in the patient. Stem cells have been acknowledged as an important vector in gene therapy for several reasons:
| 1. |
Stem cells are a self-renewing population of cells and reduce the need for repeated administrations in gene therapy. |
| 2. |
Stem cells are easily obtained by non-intrusive methods such as cord blood collection. |
| 3. |
They are easily identified and manipulated in the lab and can be returned to patients by a simple infusion. |
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Hematopoietic stem cells are able to give rise to many different types of blood cells.
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In the May 19 th, 2005, issue of the New England Journal of Medicine, Escolar et. al. reported that they had carried out successful umbilical cord blood transplants in babies with infantile Krabbe’s disease. Infantile Krabbe’s disease results in progressive neurologic deterioration and death in early childhood. The extensive study was carried out on 25 newborns with infantile Krabbe’s disease using umbilical cord blood from unrelated donors. It was found that transplantation of umbilical cord blood from unrelated donors in newborns with infantile Krabbe’s disease favorably altered the natural history of the disease. Infants who underwent transplantation before the development of symptoms showed progress in developmental skills, as well as cognitive function and receptive language skills equivalent to that of normal unaffected infants.
