Embryonic Stem Cells
Embryonic Stem Cells
Are embryonic pluripotent stem cells the best cells to use?
Answer: Although pluripotent stem cells may exhibit high diversity by differentiating into a variety of tissues in a Petri dish, there is no evidence to date that such cells are going to perform well as healthy-replacement tissues in patients. There is misinformation surrounding the potential of embryonic stem cells based on their pluripotent nature or plasticity in a Petri dish. On the contrary, the plasticity and pluripotent potential of embryonic stem cells has significant obstacles to overcome before they become suitable replacement cells. Since these stem cells are quite dynamic and diverse, they exhibit very uncommitted and uncontrolled growth, genetic instability and unpredictability. Injection of embryonic stem cells into rodents has consistently produced teratomas or tumors.
It is important to remember that embryonic stem cells are normally subjected to a dynamic metamorphous during development by the regulation of chemical signals that turn on and off during development, and these signals are unknown and very poorly understood. When these cells are removed from their normal embryonic environment and these factors are not reproduced under artificial conditions, there is no prediction on how functional or safe these cells will perform in patients.
For example, though embryonic stem cells differentiate into pancreatic tissue, the tissue do not produce insulin or can be regulated by the level of blood glucose level for the long term, which are required features in normal pancreatic islet cells. Although some scientist criticize adult stem cells because they exhibit less plasticity under culture conditions, this restriction may serve as an advantage because the stem cell has passed through a period of committed growth and stability, which makes them less likely to form tumors. Thus, stem cell plasticity and pluripotency does NOT necessarily translate into a superior stem cell. It is fair to say that there is no way to judge whether embryonic stem cell researchers will solve the fundamental scientific obstacle of genetic stability and tumor formation. It has not been documented that human embryonic stem cells can achieve any therapeutic benefit for patients. Since the IPS cell can produce the same pluripotent stem cell features as an embyronic stem cell, it is now concerivable that induced pluripotent stem (IPS) cells can replace embryonic stem cells as the preferred pluripotent stem cell for therapeutic investigation.