Various attempts have been made to straightly change somatic cells into pluripotent cells.
There is constrained use of ES cells due to ethical laws and concerns, this causes no possibility of generating patient specific ES cell lines.
In order to over come this handicap, patient-specific induced pluripotent stem cell lines have been subjected from patients with Parkinson's disease (Park et al 2008), Fanconi anemia (Raya et al. 2009) and sickle cell anemia (Ye et al.2009) and this eradicate the risk of immune-rejection with cell replacement therapies.
Induced pluripotent cells, the first pioneered approach by Shinya Yamanaka's group enables successfully reprogramming of somatic cells to pluripotent state through over expression of pluripotency in relation with transcription factors.7
After one year the same group (Takahashi 2007) and another group (Yu 2007) successfully generated human induced pluripotent cells although direct programming of defined transcription factors that are highly expressed in pluripotent cells.
Induced pluripotent stem cells comprise unique characteristic features of differentiating into all types of cells of human body known as somatic cells.
Much progress has been achieved with relation to higher scale competence, assimilating free strategy in the innovation of induced pluripotent cells. ([Jin Z.-B., Okamoto S., Mandai M. and Takahashi M. 2009 Induced pluripotent stem cells for retinal degenerative diseases: a new perspective on the challenges. J. Genet. 88, 417-424]
In view of human induced pluripotent stem cells, the first report Takahashi et al. (2007) along with his colleagues showed a relatively low output of colonies based on ES.
But now , many groups submitted highly efficient induced pluripotent stem cells with the addition of supplement factors like valproic acid (histone deacetylase inhibitor) and the SV40 large T antigen ( Huang fu et al. 2008; Mali et al 2008).
Much progress has been made by Yamanaka's group projected in discovering a non-viral method demonstrating the virus vectors altered by plasmids (okita et al.2008)
Recently, non-integrating episomal vectors (Yu et al. 2009) are being used to generate induced pluripotent stem cells directly.
In addition, the induced pluripotent cells' production have been shown to increase by using micro RNA- a class of short single - stranded RNA molecules(Judson et al. 2009).
-These induced pluripotent cells have the potential to differentiate into any cell types , making them a potential source from which to produce cells as a therapeutic platform for the treatment of wide range of diseases. (Protective effects of human induced pluripotent stem cells-derived retinal pigment epithelium cell transplantation as in the retinal dystrophic rat) Carr AJ
Induced Pluripotent Stem cells have been produced from patients with Parkinson's disease, thalasaemia, amyotrophic lateral sclerosis, type 1 diabetes mellitus,Fanconi anemia, adenosine deaminase deficiency-related severe combined immunodeficiency,Shwachman-Bodian-Diamond syndrome, Gaucher disease type III, Duchenne and Becker muscular dystrophy,Huntington disease, juvenile-onset, , Down's syndrome/trisomy 21, and Lesch-Nyhan syndrome(Dimos et al. 2008; Park et al. 2008;Raya et al. 2009; Ye et al. 2009).
These cells also provide a capability based on disease models. Most of human inherited diseases are miscellaneous with link to genetics and clinical basis.
Different genes comprising of most mutations that give rise to distinct diseases and the distinct phenotype given by each mutation and with this link for each reported mutation, it is not possible to create animal models, but it is possible to create such induced pluripotent stem cells as disease models.
Taking into an account, establishing appropriate therapies are not possible for most retinal degenerative diseases like AMD and RP.
In order to over come from above , if patient's own induced pluripotent cells capable of generating useful retinal neurons can be a good idea for eradicating different mechanisms of disease. This would an ease to find information based on intrinsic factors such as apoptosis in patients.
Also point to be noticed that these cells also provide a capability based resource for drug screening and biological resource.
It has been mention that ES cells have been used for study pharmacology (Ho and Li 2006).
Induced pluripotent cells can also be subjected as biological tool for toxicity screening in addition to drug discovery.
Like during regular research, there is unavailability of retinal cells from patients, these cells helps during clinical trials to examine both toxicity and effectiveness of a new drug([Jin Z.-B., Okamoto S., Mandai M. and Takahashi M. 2009 Induced pluripotent stem cells for retinal degenerative diseases: a new perspective on the challenges. J. Genet. 88, 417-424]