induced Pluripotent Stem Cell (iPS) is a newer concept in the field of stem cell therapy. Let us see how it promises us a newer and brighter future…
Stem Cell- Name of a New Light in the World of Therapeutics
Stem cell research has been a hot topic among the biotechnologists since the last two decades. During this period stem cells are worked upon at a very fast rate due to its immense potential in therpeutic research and medical application.
Pluripotent Stem cells are a type of stem cell that has the ability to differentiate into any type of tissue except extra-embryonic tissue such as placenta. Pluripotent Stem cells are derived mainly from embryonic cells.
Embryonic stem cells (ES cells) are stem cells derived from the inner cell mass of an early stage embryo known as a blastocyst. Human embryos reach the blastocyst stage 4–5 days post fertilization, at which time they consist of 50–150 cells.
Hurdles in ES Research
The biggest hurdle that was posed in the way of implementation of ES cell in application and over its research is by the religious leaders from Vatican [stemcell.taragana.net/archive/vatican-warns-obama-against-embryonic-stem-cell-research/#more-1763] who considered it to be crime since it aimed at manipulating embryo cells of human which they compared to as the budding lives. In the year 2001 George W. Bush banned research in ES cells and stopped all the fundings related to the research. With change in power in US in the beginning of this year, 2009 [stemcell.taragana.net/archive/will-federal-ban-on-embryonic-stem-cell-research-be-over/#more-1788] , it was hoped that Barrack Obama would loosen the restriction over stem cell research. Finally as was expected funding in ES cell research was revived in March, 2009. It has also been approved by the FDA recently.
New Avenues for Deriving Pluripotent Cells
During the period since 2001, scientist started to explore new ways of obtaining pluripotent cells from different other sources. This lead to the finding of adult stem cells obtained from bone marrow cells. These cells were engineered to become pluripotent with some modifications. Though it was seen that the obtained cells were less prone to teratoma formation or did not produce any graft vs host reactions, it was found that its very difficult to grow the cells conventionally in laboratories and also they are limited in their use.
Therefore scientists moved forward towards thinking about a much better method to obtain pluripotent cells, which they ultimately succeeded by developing induced pluripotent Stem cells (iPS).
induced Pluripotent Stem Cells (iPS)
Advantage of iPS Cells
The main advantages of iPS cells are that:
- They can be propagated almost indefinitely under laboratory conditions.
- They can be easily genetically modified and, in principle, be induced to differentiate into any desired cell type.
- The wide-scale application of iPS cells by necessity involves a `therapeutic cloning’ step to overcome problems of tissue rejection after engraftment. This in turn raises major practical considerations.
How it is engineered?
To create the iPS cells, the scientists started with cells which were modified by a standard lab technique employing retroviruses customized to insert genes into the cell’s DNA. The inserted genes were Oct4, Sox2, Lif4 and c-Myc, known to act together as master regulators to keep cells in an embryonic-stem-cell-like state. iPS cells were selected based on their morphology and then verified to express gene markers specific to embryonic stem cells. To decrease or eliminate possible cancer in the treated cells, the c-Myc gene was removed by genetic manipulation from the iPS cells.
Recent Challenges to iPS
The titanic challenge with which scientists are still finding hard to fight with is the transplantation od these cells into the host. Referring to a recent article it has been seen that four approaches were made in this direction but unfortunately all the four faced a heavy loss. Enumerated as :
•Two international teams, one led by Keisuke Kaji of the U.K.’s University of Edinburgh and the other headed by Andras Nagy of Mount Sinai Hospital in Toronto, separately announced ways to insert raw DNA containing the cancer genes into the cells and then strip the DNA out once the genes have done their work, a process that leaves behind a few mutations in the cells.
•A group led by Rudolph Jaenisch of the Whitehead Institute in Cambridge, Mass., used removable viruses to deliver the cancer genes. Once the viruses were taken out, only traces of the cancer genes remained.
•A group led by embryonic stem cell pioneer James Thomson of the University of Wisconsin attached the cancer genes to free-floating plasmid genes that don’t enter the nucleus of the cell. Because the cancer genes aren’t in the nucleus, they disappear when the cells reproduce, neatly removing them from subsequent generations of cells.
• A group headed by Kwang-Soo Kim of Harvard Medical School reported that skin cells treated with proteins from the cancer genes, not the genes themselves, created two induced cell lines, or colonies.
So by far though induced Pluripotent Stem cells (iPS) has been successful in getting away scot free from the Popes and the People of Bioethics, it has to find a way to get into the host body through a safe path.
Medical Application of induced Pluripotent Stem Cells:
Stem cells have found to be of great use to replace verious defective cells in order to cure several diseases as enumerated below:
Though scientists are exploring new avenues and trying to think differently just in order to find a replacement to ES cells, according to an unbiased view, it can be said that it might have been less painstaking for them if ES cells would have been accepted. As a result of which till date what could have been a boon of this society through the blessing of the discovery of ES cells, and might have cured a million, it still remains as a topic of debate in some corner of a lawsuit. Also due to these debates a lot of funds are being invested to find something new to bypass this strategy, where the same could have been used conventionally.
It can be pointed out that though practices such as research involving guniea pigs and even monkeys (one of the closest relatives of Homo sapiens) are employed in researches so why not “a not still human” embryo cell be not utilised for something better which can really help the cause of curing human ailments.
But viewing this matter from a neutral side, it can be said that a lot of new things has come into being as a result of these controversies. So can we say proudly that induced Pluripotent Stem cells are “A Blessing in Disguise”?
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