Blind World Magazine

Stem cells promise cure for vision loss.




SCIENCE.
Wednesday April 19 2006.




NEW DELHI: Age-related degeneration of vision has been a common problem, which so far has no cure. However, an ongoing stem cell study at AIIMS might just provide a solution.


For about six months now, Dr Rajender Prasad Centre for Opthalmic Sciences at AIIMS has been studying the effect of stem cells in patients who suffer from degenerative vision disorders — the patients taken in the Phase I of study can’t see beyond 3 metre and according to the WHO classification are termed ‘blind’.


The study is being conducted on patients who have age-related vision loss or are affected by Retinitis pigmentosa — a heritable group of blinding diseases resulting from loss of photoreceptors, primarily rods and secondarily cones that mediate central vision.


The study, which has got clearance from the Ethics Committee of the Department of Biotechnology, Ministry of Science and Technology, and also from AIIMS Ethics Committee, is focusing on 50 patients.


The initial results have been encouraging. According to doctors at the centre, significant improvement has been noticed in vision of the patients after one month of injecting stem cells. There is further improvement after a gap of three months.


‘‘Since this is the Phase I clinical trial undertaken to study safety and preliminary indicators of efficacy in patients with retinal degenerative disorders, we are taking patients with nearly zero vision. Our studies have shown that there is vision enhancement of at least a few metres, which is significant considering that the patients had near zero vision,’’ says Dr Atul Kumar, Professor of Opthalmology and head of the team undertaking the research at the centre.


The researchers are using autologous (derived from patient’s own body) bone marrow derived stem cells and injecting them into the eyes of the patients.


‘‘The cells are derived from the hip bone of the patient by sucking them out with a syringe,’’ said Dr Kumar. The cells are sterilized and centrifuged so that the doctors obtain a high concentration of the cells. Cells are also checked if they are viable, that is, whether they are alive and have the capability of transforming into ocular cells.


‘‘ There has been some success with transplantation of neural stem cells, but this approach is limited by political and ethical controversies related to the use of embryonic stem cells, as well as by cell rejection. So we are using cells derived from patient’s own body,’’ said Dr Kumar.


The stem cells derived in this manner are injected into a loose tissue near the cornea. ‘‘This is done by a fine 25 gauge needle (less that 0.1 mm), which is barely visible to the naked eye. A dose of 0.1 ml is injected under local anaesthesia,’’ the doctor said.


A subsequent dose of antibiotics is given so that the area doesn’t develop infection following the injection. Next morning, the patient is discharged. ‘‘We do a follow-up after one month followed by checks after three, six and 12 months,’’ added Dr Kumar.




End of article.



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