A 60-year-old woman and an 86-year-old man suffering from age-related macular degeneration (DMLE) have partially regained their lost visual acuity thanks to the transplantation of embryonic stem cells. The success of the first phase of clinical trials of this new technique, the report of which was published in the well-known magazine Nature Biotechnology, was achieved by a group of British doctors from Moorfields Eye Hospital as part of the London Project to Cure Blindness.
What is AWD
The DMLE is today one of the main causes of blindness due to the loss of central vision, in respect of which irreversible degeneration of the retinal pigment epithelium (EPR), a layer of cells whose function is to nourish the photoreceptors, the cells responsible for central vision (cones and rods) located in the macula, the central part of the retina. L'physiological ageingIn fact, as a result of a multiplicity of concomitant factors (genetic, environmental, systemic disease-related, lifestyle-related, etc.), it can lead to the onset of this serious senile eye disease that results in decreased vision, difficulty in reading, loss of colour recognition and difficulty in performing normal daily activities.
There are two forms of AMD:
-the dry' form, which affects approximately 90% of all macular degeneration, characterised by the accumulation below the macula of deposits of yellowish material, the drusenwhich progressively alter the functionality of the cells responsible for perceiving light stimuli;
-the wet' or exudative form, fortunately less frequent than dry, but with a more disabling outcome, characterised by the formation of small abnormal blood vessels below the macula. These vessels, with very fragile walls, can easily ooze fluid, or they can rupture, causing haemorrhages in the retina.
The embryonic stem cell experiment
The researchers of the Moorfields Eye Hospital in London managed to introduce embryonic stem cells into cells of the retinal pigment epithelium. The monolayer of EPR cells was inserted into a very thin synthetic membrane, which they called a 'patch', and then implanted into the sub-retinal space of one eye in both patients.
Following this intervention, both patients, suffering from severe exudative AMD, showed an improvement in visual acuity: the woman was able to read approximately 83 words per minute; the man, on the other hand, went from no reading ability at all to 43 words per minute.
However, although this technique is promising and may open up new frontiers in the therapeutic field, the trial has still been conducted on too small a number of patients whose follow-up ended in one year.
In the near future, the experiment will be repeated in eight more patients so that efficacy and any occurrence of adverse events can be better evaluated in the long term.
Bibliography
by Cruz L, et al. Phase 1 clinical study of an embryonic stem cell-derived retinal pigment epithelium patch in age-related macular degeneration. Nat Biotechnol. 2018. doi:10.1038/nbt.4114
Dr. Carmelo Chines
Direttore responsabile
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