Embryonic Stem Cells
Adult stem cells have several shortcomings and this is where the embryonic stem cells (ESCs) become useful.
ESCs began to be projected as the best candidates for obtaining pleuripotent stem cells, as they were undifferentiated cells with immense potential to grow into any type of cells.
Human embryos that were created in IVF labs after an artificial reproductive technology (ART) were the ideal candidates. Day-5 embryos, also known as a blastocyst, had a reservoir of pleuripotent stem cells.
But hope soon began to fade as the technique became riddled with ethical challenges. Scientists began to look elsewhere and, soon enough, they started coming up with more feasible alternatives.
Out of this effort the induced pleuripotent stem cells (iPS)) took shape. It was discovered by Japanese scientists that skin cells can be reprogrammed to become embryonic stem cells. This is done by introducing the appropriate genes into the skin cells, through viral vectors, and by using an external stimuli as a trigger.
This technique takes care of the ethical issues swathed around the embryonic stem cells. It has immense potential as it can be used to create neurons, heart muscles, cartilage, liver and bladder cells.
However, involvement of the viral vector is worrying and non-viral alternatives are being looked into.
