Treatment for commonest form of blindness moves a step closer

The scientists used health human eye tissue donated post mortem to the Manchester Eye Tissue Repository.

They identified those who are risk of developing age-related macular degeneration based on their risk genes, and discovered underlying changes in the tissue of the otherwise healthy at-risk individuals.

They collected retinal tissue from the back of donor eyes post mortem, following removal of the cornea for transplantation.

Then they took a small sample from the macula – the part of the retina responsible for central vision – and removed the cells to leave a thin layer of membrane which supports the photoreceptors called rod and cone cells and is where disease begins.

They analysed the proteins present in the membrane from 30 people using mass spectrometry, which identifies protein components based on their mass, to find differences in the tissue make-up between those with and without genetic risk of AMD.

The mass spectrometry, identified a series of enzymes which are made almost exclusively by mast cells, a type of immune cell.

Examining tissue from a further 53 people, they observed higher levels of mast cells in patients with higher disease risk.

Dr Unwin added: “We next need to look at how mast cells are activated, and whether by preventing, or clearing mast cell activation we can slow or stop disease development.

“There are several researchers and companies looking at complement mediated-therapies for AMD and while these are promising for Chr1-related disease there is no evidence that they will have an effect on Chr10 disease.

“A therapy designed to target mast cell activation as a unified mechanism could in theory treat all patients with AMD and prevent sight loss “

Geraldine Hoad, the Macular Society’s research manager, said: “This is an exciting development and we look forward to seeing further research in this area. We know lots of current treatments for wet AMD don’t work for everyone and for those with dry AMD there is no treatment at all.  Finding something that works for everyone would be an important piece of the puzzle and make a huge difference to the lives of those affected.

“While this particular study is in its early stages. it’s great to see the benefit of our investment in the Manchester Eye Tissue Repository, which is proving a vital resource for lots of research in this area.”

The paper  Mast cell infiltration of the choroid and protease release are early events in age-related 2 macular degeneration associated with genetic risk at both chromosome 1q32 and 10q26 is published in PNAS

The Macular Society is the leading sight loss charity for people affected by macular disease. If you are affected by the conditions, or know someone contact the Society’s Advice and Information Service on 0300 3030 111 or email help@macularsociety.org. Alternatively for more information on macular disease visit macularsociety.org

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