Late-onset retinal degeneration (L-ORD) is a rare autosomal dominant retinal dystrophy, characterised by extensive sub-retinal pigment epithelium (RPE) deposits, RPE atrophy, choroidal ...neovascularisation and photoreceptor cell death associated with severe visual loss. L-ORD shows striking phenotypic similarities to age-related macular degeneration (AMD), a common and genetically complex disorder, which can lead to misdiagnosis in the early stages. To date, a single missense mutation (S163R) in the C1QTNF5 gene, encoding C1q And Tumor Necrosis Factor Related Protein 5 (C1QTNF5) has been shown to cause L-ORD in a subset of affected families. Here, we describe the identification and characterisation of three novel pathogenic mutations in C1QTNF5 in order to elucidate disease mechanisms. In silico and in vitro characterisation show that these mutations perturb protein folding, assembly or polarity of secretion of C1QTNF5 and, importantly, all appear to destabilise the wildtype protein in co-transfection experiments in a human RPE cell line. This suggests that the heterozygous mutations in L-ORD show a dominant negative, rather than a haploinsufficient, disease mechanism. The function of C1QTNF5 remains unclear but this new insight into the pathogenetic basis of L-ORD has implications for future therapeutic strategies such as gene augmentation therapy.
Purpose
The PAUL® glaucoma implant (PGI) is a novel glaucoma drainage device, which has not been previously reported in paediatric glaucoma management. This study aims to evaluate the safety and ...effectiveness of the PGI in a paediatric cohort.
Methods
A retrospective evaluation of 25 cases of paediatric PGI surgery (age 8 months to 16 years) was performed at Manchester Royal Eye Hospital between September 2019 and July 2020. Primary outcome measures included failure (intraocular pressure (IOP) > 21 mmHg or < 20% reduction of IOP, removal of the implant, further glaucoma intervention or visual loss. Secondary outcomes included mean IOP, mean number of medications, logMAR visual acuity and complications.
Results
Eleven eyes (48%) had a complete success and achieved an unmedicated IOP < 21 mmHg, and 21 eyes (84%) had a qualified success (with or without medications). Four failures were observed, 2 due to hypotony and 2 underwent further surgery (gonioscopy-assisted transluminal trabeculotomy). The mean preop IOP was 30.9 ± 5.9 mmHg (
n
= 25), falling to 13.5 ± 6.8 mmHg at 1 month, 17.9 ± 7.2 mmHg at 3 months, 13.4 ± 5.1 mmHg at 6 months, 13.2 ± 4.9 mmHg at 12 months and 11.8 ± 4.6 mmHg at 24 months. The mean change in IOP from the preoperative visit to the last visit was a reduction of 19.1 ± 7.7 mmHg. A significant reduction in the number of medications and IOP was demonstrated after PGI (
p
< 0.0001). Nine patients required removal of the intraluminal Prolene stent from the PGI for further pressure lowering.
Conclusion
The one- to two-year results demonstrate paediatric PGI has high qualified success rates and effectively reduces IOP and the need for glaucoma medical therapy.
The aim of this study was to determine whether mutations in mitochondrial DNA play a role in high-pressure primary open-angle glaucoma (OMIM 137760) by analyzing new data from massively parallel ...sequencing of mitochondrial DNA.
Glaucoma patients with high-tension primary open-angle glaucoma and ethnically matched and age-matched control subjects without glaucoma were recruited. The entire human mitochondrial genome was amplified in two overlapping fragments by long-range polymerase chain reaction and used as a template for massively parallel sequencing on an Ion Torrent Personal Genome Machine. All variants were confirmed by conventional Sanger sequencing.
Whole-mitochondrial genome sequencing was performed in 32 patients with primary open-angle glaucoma from India (n = 16) and Ireland (n = 16). In 16 of the 32 patients with primary open-angle glaucoma (50% of cases), there were 22 mitochondrial DNA mutations consisting of 7 novel mutations and 8 previously reported disease-associated sequence variants. Eight of 22 (36.4%) of the mitochondrial DNA mutations were in complex I mitochondrial genes.
Massively parallel sequencing using the Ion Torrent Personal Genome Machine with confirmation by Sanger sequencing detected a pathogenic mitochondrial DNA mutation in 50% of the primary open-angle glaucoma cohort. Our findings support the emerging concept that mitochondrial dysfunction results in the development of glaucoma and, more specifically, that complex I defects play a significant role in primary open-angle glaucoma pathogenesis.
The primary cause of failure for minimally invasive glaucoma surgery (MIGS) is fibrosis in the trabecular meshwork (TM) that regulates the outflow of aqueous humour, and no anti-fibrotic drug is ...available for intraocular use in MIGS. The myocardin-related transcription factor/serum response factor (MRTF/SRF) pathway is a promising anti-fibrotic target. This study aims to utilise a novel lipid nanoparticle (LNP) to deliver MRTF-B siRNA into human TM cells and to compare its effects with those observed in human conjunctival fibroblasts (FF). Two LNP formulations were prepared with and without the targeting peptide cΥ, and with an siRNA concentration of 50 nM. We examined the biophysical properties and encapsulation efficiencies of the LNPs, and evaluated the effects of
silencing on cell viability, key fibrotic genes expression and cell contractility. Both LNP formulations efficiently silenced
gene and were non-cytotoxic in TM and FF cells. The presence of cΥ made the LNPs smaller and more cationic, but had no significant effect on encapsulation efficiency. Both TM and FF cells also showed significantly reduced contractibility after transfection with MRTF-B siRNA LNPs. In TM cells, LNPs with cΥ achieved a greater decrease in contractility compared to LNPs without cΥ. In conclusion, we demonstrate that the novel CL4H6-LNPs are able to safely and effectively deliver MRTF-B siRNA into human TM cells. LNPs can serve as a promising non-viral gene therapy to prevent fibrosis in MIGS.
ObjectivesTo describe a surgical technique and early post-operative outcomes for a novel glaucoma drainage device—the PAUL® glaucoma implant (PGI).MethodsA consecutive cohort study of subjects who ...had PGI surgery between February 2019 and May 2020 with a minimum of 6-month follow-up. Primary outcome measures included failure (intraocular pressure (IOP) > 21 mmHg or a <20% reduction of IOP, removal of the implant, further glaucoma intervention or visual loss to no light perception). Secondary outcomes included mean IOP, mean number of medications, logMAR visual acuity (VA) and complications.ResultsNinety-nine eyes of 97 patients had a preoperative IOP (mean ± standard deviation) of 28.1 ± 9.0 mmHg, falling to 18.2 ± 6.8 mmHg at 1 month, 17.9 ± 6.7 mmHg at 3 months and 13.6 ± 4.7 mmHg at 6 months. 52 patients had a 12-month mean IOP of 13.3 ± 4.4 mmHg. The mean change in number of medications was a reduction of 2.38 ± 1.48. A significant reduction in the number of medications and intraocular pressure was demonstrated after PGI (p < 0.0001). No significant change was demonstrated in VA (p = 0.1158). A total of nine cases were deemed failures (six had <20% IOP reduction from baseline and three had IOP >21 mmHg). Thirty-eight (38.4%) of eyes had complete success and achieved an unmedicated IOP <21 mmHg. Ninety (90.1%) of eyes were qualified successes (with or without topical medications). Seventy-four (74.7%) eyes have achieved an intraocular pressure of <15 mmHg. Two cases of hypotony were observed.ConclusionThis study presents a safe surgical technique, which significantly reduces IOP and number of medications with minimal complications.
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