Retinal A to Z. Five subpopulations of distinctly different cells were found in the RPE layer – researchers used AI to analyze single-cell resolution images. Five concentric RPE populations were identified, along with subpopulations with different susceptibility to monogenic and polygenic retinal diseases. These findings will help the development of specific cell and gene therapies to target retinal diseases. Link
Optical powerhouses. A research group from the National Eye Institute in Bethesda, Maryland, US, has shown that mitochondria aggregated by mammalian photoreceptors act as a microlens and focus light entry into the outer segment, remodeling themselves to alter light concentration. This phenomenon is essential in improving resolution – the insight given from this study is relevant to clinical ophthalmic imaging, and may help early diagnosis of retinal diseases. Link
Unintended consequences. Researchers analyzing health insurance claim records of over 213,000 American men found an increase in the risk of serous retinal detachment, retinal vascular occlusion, and ischemic optic neuropathy in those who regularly use phosphodiesterase type 5 inhibitors (PDE5Is), used in the management of erectile dysfunction. This data is important, as previous results on this subject are conflicting and epidemiological data are non-existent. People using PDE5Is will need to be aware of these adverse events, and alert their physicians at the first sign of trouble. Link
Double trouble. A study of 502 participants assessed associations of the two most common genetic risk loci for AMD with disease progression: CFH-CFHR5 on chromosome 1 and ARMS2/HTRA1 on chromosome 10. The risk of disease onset was increased in people who carried two risk alleles for each of the loci. The findings suggest that AMD disease progression is associated with these loci through distinct biological mechanisms, and warrant consideration when designing clinical trials. Link
New foundations. In vivo correction of an Rpe65 mutation by adenine base editor has been demonstrated to prolong the survival of cones in a mouse model of Leber congenital amaurosis. The findings highlight base editing as a potential gene therapy that could confer long-lasting retinal projection. Link
Ophthalmic oracle. Relative telomere length (RTL) is now associated with risk of AMD, but only in women. A previous link between physiological aging and RTL had been established, so researchers sought to establish a link to AMD in a 2,262 strong, elderly cohort. The results are in tune with levels of reactive oxygen species levels and higher telomerase activity in women. Link
In Other News…
Sight after death. Scientists describe how they were able to revive retinal neurons and restore light signalling in the post-mortem mouse and human retina. Link
Road to recovery. A recent study shows that a treatment for retinal vein occlusion has long-lasting advantages for vision – but patients require ongoing treatment. Link
‘Allo ‘Allo! A clinical trial of allogenic RPE transplant patch has shown it survive for two years post implantation, with researchers looking to secure FDA approval. Link
In the womb. UK’s National Health Service is rolling out a non-invasive test capable of identifying babies’ risk of developing retinoblastoma – in utero. The test, developed at Birmingham’s Women’s and Children’s Foundation Trust, uses a maternal blood sample and has almost 100 percent accuracy, enabling treatment straight after delivery. Link
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