http://www.hammondopticians.co.uk/wp-content/uploads/2015/09/hammond-opticians-enfield.png 0 0 hammondopticians http://www.hammondopticians.co.uk/wp-content/uploads/2015/09/hammond-opticians-enfield.png hammondopticians2014-04-03 10:05:482014-02-22 14:23:05Human Müller cells restore function of rat retinas
Stem cells derived from human eyes have been used to restore vision in rats with damaged photoreceptors.
Müller cells were harvested from human donor tissue and transplanted into the retinas of blind rats where they partially restored vision, with scans showing that half of the signals between the eye and the brain had been recovered.
The approach could be used to treat a range of conditions, such as AMD, diabetic retinopathy and retinitis pigmentosa.
Previous research had shown that in some species, such as zebra fish, stress or injury to the eye can kick-start Müller cells back into the cell cycle. The cells can then develop into different types of cell in the retina to repair the damage, however, this spontaneous cellular awakening is not seen in human Müller cells.
After the cells were harvested from human tissue they were cultured in the lab and given chemical growth factors to persuade them to enter a stem-cell like state, forming human Müller stem cells (hMSCs). Once they had been injected into the retinas, the hMSCs developed into rod cells which were responsive to light signals.
Stem cell characteristics
Unlike other types of stem cells, such as those obtained from embryos, hMSCs are already part matured and so are restricted to becoming only retinal cells. This may avoid issues which can be associated with other types of stem cells, such as the risk of forming tumours, said researchers involved in the study.
“They have all the characteristics of stem cells,” said Dr Hari Jayaram, one of the study authors and clinical lecturer at the NIHR Moorfields Biomedical Research Centre in London. “It’s relatively easy to isolate these cells from donor tissue,” he added.
Speaking of the potential clinical application for the approach, he told OT: “In terms of transplantation, you could in theory take a sample of retina from [a patient], culture the cells and put them back.”
“It’s the timescale which is significant,” explained Dr Jayarama, “[it is] significantly shorter than for using embryonic stem cells.” He explained that while developing embryonic stem cells lines can take months, Müller cells can be developed ready for transplantation in as little as a week.
This approach could pave the way for personalised medicine, where using a patient’s own cells would also avoid the issue of rejection which may be associated with using stem cells from another individual.
The next steps, explained Dr Jayaram, is to develop clinical grade cell lines for trials in humans, but it’s feasible that a viable treatment using the approach could be available within five years. One consideration with the approach, however, is that the cells would need to be tissue matched with potential recipients in order to reduce the risk of rejection. This could be achieved by generating a number a small number of cell lines which could be used for a wide range of patients.
Dr Paul Colville-Nash of the Medical Research Council, who supported the work, said that the cells provided “another avenue of exploration for cell therapy in retinal diseases”.