Heredity in primary open-angle glaucoma

Glaucoma and its predictors among adult patients attending ophthalmic outpatient department: a hospital-based study, North West Ethiopia

BACKGROUND

Nearly 1.9% of global blindness is caused by glaucoma and this is sadly high in Africa which is around 15% and In Ethiopia, glaucoma is responsible for 5.2% of blindness. It is also the fifth cause of blindness in Ethiopia. Scarce information is available regarding glaucoma in Ethiopia; hence we determined the proportion of glaucoma and its associated factors in North West Ethiopia which will be utilized for future related researches and different stakeholders.

METHODS

Institution based cross-sectional study was conducted from September 1/2020 to February 30/21 among 258 adults aged 40 and above years old. The participants were selected using the systematic random sampling technique. The data was collected using an interview-administered questionnaire. Binary and Multi-variable logistic regressions were fitted to identify independent predictors of glaucoma. P-value less than 0.05 were used as a cutoff point for declaring statistical significance.

RESULTS

The prevalence of glaucoma was 66(26%) with a 95% CI of 17.7, 35.4%). Individuals with Positive family history of glaucoma (AOR: 3.72, 95% CI: 1.03-3.53), age (AOR: 3.21, 95% CI: 1.92-5.99) and elevated intraocular pressure (AOR: 3.09, 95% CI: 1.45-6.59) were statistically significant contributing factors for the development of glaucoma.

CONCLUSION

The study found a relatively high proportion of glaucoma in the study area, which is primarily a disease of the elderly. Age, elevated intraocular pressure, and positive family history of glaucoma was contributing factors for the emergence of glaucoma. Therefore, establishing public awareness programs about the identified risk factors for the prevention and early detection of cases is essential.

Characterization of a novel mutation in the MYOC gene in a Chinese family with primary open‑angle glaucoma

Although primary open-angle glaucoma (POAG)-related mutations in the myocilin (MYOC) gene have been reported, the underlying associations remain poorly understood. In the present study, the relationship between a MYOC mutation and POAG was investigated using ophthalmic examination and total exon gene sequencing in a Chinese family comprised of 5 individuals with POAG and 15 unaffected individuals. Pathogenic mutations underlying POAG were identified by whole-exome sequencing and subsequently validated by Sanger sequencing. Of the family members, nine (45%) harbored heterozygous p.D208Y mutations; among these, five had POAG and four were unaffected. The mean age at diagnosis was 26.2±4.12 years and the mean intraocular pressure (IOP) was 39.7±16.58 mmHg; all affected members complained of vision loss, headaches and eye swelling. Among the five cases of POAG, two presented with blindness. Among 10 members of the family who underwent comprehensive ophthalmologic examination, 3 individuals exhibited severe visual field defects. The mean age at the time of operation was 27.2±3.54 years. In the present study, a novel MYOC mutation (c.G622T: p.D208Y) was identified that was associated with severe visual impairment, high IOP and the need for frequent surgical interventions. Some carriers of the mutation were young and did not show signs of glaucoma. These individuals should be followed-up to firmly establish whether the mutated gene is pathogenic for POAG.

Canaloplasty for the treatment of primary open-angle glaucoma: A protocol of systematic review and meta-analysis

BACKGROUND

Canaloplasty has been reported to manage primary open-angle glaucoma (POAG) effectively. However, no study has specifically and systematically investigated the efficacy and safety of canaloplasty for the treatment of POAG. Thus, this study will systematically and comprehensively appraise the efficacy and safety of canaloplasty for the treatment of POAG.

METHODS

MEDLINE, EMBASE, Cochrane Library, Web of Science, Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure will be sought from the construction to the February 29, 2020. Only randomized controlled trials (RCTs) focusing on canaloplasty for the treatment of POAG will be included. Two reviewers will independently undertake selection of study, data extraction, and risk of bias assessment. Any doubts between 2 reviewers will be resolved through discussion with another experienced reviewer. RevMan 5.3 software will be employed for data analysis.

RESULTS

This study will summarize high-quality RCTs on investigating efficacy and safety of canaloplasty for the treatment of POAG.

CONCLUSION

The findings of this study will help to determine whether canaloplasty is effective and safety for the treatment of POAG.Systematic review registration: INPLASY202040119.

Cholinergic nervous system and glaucoma: From basic science to clinical applications

The cholinergic system has a crucial role to play in visual function. Although cholinergic drugs have been a focus of attention as glaucoma medications for reducing eye pressure, little is known about the potential modality for neuronal survival and/or enhancement in visual impairments. Citicoline, a naturally occurring compound and FDA approved dietary supplement, is a nootropic agent that is recently demonstrated to be effective in ameliorating ischemic stroke, traumatic brain injury, Parkinson's disease, Alzheimer's disease, cerebrovascular diseases, memory disorders and attention-deficit/hyperactivity disorder in both humans and animal models. The mechanisms of its action appear to be multifarious including (i) preservation of cardiolipin, sphingomyelin, and arachidonic acid contents of phosphatidylcholine and phosphatidylethanolamine, (ii) restoration of phosphatidylcholine, (iii) stimulation of glutathione synthesis, (iv) lowering glutamate concentrations and preventing glutamate excitotoxicity, (v) rescuing mitochondrial function thereby preventing oxidative damage and onset of neuronal apoptosis, (vi) synthesis of myelin leading to improvement in neuronal membrane integrity, (vii) improving acetylcholine synthesis and thereby reducing the effects of mental stress and (viii) preventing endothelial dysfunction. Such effects have vouched for citicoline as a neuroprotective, neurorestorative and neuroregenerative agent. Retinal ganglion cells are neurons with long myelinated axons which provide a strong rationale for citicoline use in visual pathway disorders. Since glaucoma is a form of neurodegeneration involving retinal ganglion cells, citicoline may help ameliorate glaucomatous damages in multiple facets. Additionally, trans-synaptic degeneration has been identified in humans and experimental models of glaucoma suggesting the cholinergic system as a new brain target for glaucoma management and therapy.

The clinical feature of myocilin Y437H mutation in a Chinese family with primary open-angle glaucoma

PURPOSE

To characterise the genotype(s), phenotype(s) and age-related penetrance of glaucoma in a Chinese family with primary open-angle glaucoma (POAG).

METHODS

Recruited from a Chinese family spanning four generations, 7 individuals with POAG, 1 with ocular hypertension (OHT) and 14 unaffected individuals were included in this study. Genotypic investigation included sequencing of mutation sites using a glaucoma panel in combination with high-throughput sequencing and validated using Sanger sequencing. Phenotypic characterisation included investigation into patient medical history and physical examination.

RESULTS

Eight (36.4%) family members harboured heterozygous Y437H mutation, of whom seven (87.5%) were glaucomatous and one (12.5%) had OHT. The mean age of POAG diagnosis was 30.85±7.13 years. The mean highest recorded intraocular pressure (IOP) was 46.57±6.53 mm Hg. They all had complained of symptoms associated with vision and pain. Four (57.1%) patients presented blindness. Five eyes (62.5%) presented with severe and three eyes with moderate visual field defects. Most of them underwent surgery on average 1.29±2.36 years after diagnosis, and the mean IOP at study was 17.95±7.23 mm Hg, with an average of 0.92±0.86 eye-drops. The patient with OHT was treated with latanoprost only and her IOP was well controlled. Age-related glaucoma penetrance was 0% in individuals under the age of 20 years, 50% at ages 20-35 years, 75% at ages 31-35 years and 87.5% over 45 years.

CONCLUSION

A novel MYOC mutation (c.1309T>C, p.Y437H) in a Chinese family with POAG was identified which was associated with a phenotype characterised by severe visual impairment, frequent surgical intervention requirement and relatively high penetrance.

Local genetic ancestry in CDKN2B-AS1 is associated with primary open-angle glaucoma in an African American cohort extracted from de-identified electronic health records

BACKGROUND

Glaucoma is a leading cause of blindness in developed countries. Primary open-angle glaucoma (POAG), the most prevalent clinical subtype of glaucoma in the United States, affects African Americans at a higher rate compared with European Americans. Risk factors identified for POAG include increased age and family history, which coupled with heritability estimates, suggest this complex condition is associated with genetic and environmental factors. To date, several genome-wide studies have identified loci significantly associated with POAG risk, but most of these studies were performed in populations of European-descent.

METHODS

To identify population-specific and trans-population genetic associations for POAG, we genotyped 11,521 African Americans using the Illumina Metabochip as part of the Epidemiologic Architecture for Genes Linked to Environment (EAGLE) study accessing BioVU, the Vanderbilt University Medical Center's biorepository linked to de-identified electronic health records. Among this study population, we identified 138 cases of POAG and 1376 controls and performed Metabochip-wide tests of association. We also estimated local genetic ancestry at CDKN2B-AS1, a POAG-associated locus established in European-descent populations.

RESULTS

Overall, we did not identify significant single SNP-POAG associations after adjusting for multiple testing. We did, however, detect a significant association between POAG risk and local African genetic ancestry at CDKN2B-AS1, where on average cases were of 90% African descent compared with controls at 58% (p = 2 × 10- 6).

CONCLUSIONS

These data suggest that CDKN2B-AS1 is an important locus for POAG risk among African Americans, warranting further investigation to identify the variants underlying this association.

Myocilin protein levels in the aqueous humor of the glaucomas in selected canine breeds

OBJECTIVE

To compare aqueous humor myocilin protein levels in dogs with the primary glaucomas to those with the secondary glaucomas, primary cataracts, and diabetic cataracts.

MATERIALS AND METHODS

Four groups were selected, based on diagnosis by the attending veterinary ophthalmologists and included: primary glaucoma (primary open-angle glaucoma (POAG) and primary closed angle glaucoma (PCAG); n = 155); secondary glaucoma (n = 94); primary (presumed inherited) cataract (n = 142), and diabetic cataract (n = 83). A total of 474 samples (187 males, 263 females, 24 unreported) with average ages of 117 months for the males and 101 months for the females were analyzed. Myocilin protein was measured using the Coomassie staining and Western blot methods relative to a myocilin control.

RESULTS

Differences were seen between nonglaucomatous (cataractous) and glaucomatous dogs with myocilin levels in glaucomatous eyes being many times higher than those in the cataractous dogs. Primary glaucomatous dogs were found to have an aqueous humor myocilin protein level of 17.30 +/- 1.03 units. Secondary glaucomas had the highest level of myocilin in the aqueous humor with 19.27 +/- 1.41 units. Diabetic cataractous dogs had the lowest levels of myocilin reported with 6.60 +/- 0.88 (mean +/- SEM) units. Normal (cataractous) dogs had a myocilin level in the aqueous humor of 8.05 +/- 0.86 units.

CONCLUSION

Aqueous humor protein levels were elevated, relative to the myocilin control, in both the primary and secondary glaucoma groups compared to the cataract and diabetic cataract groups. Like in the Beagle POAG, aqueous humor myocilin protein levels are increased. Further studies are indicated to investigate the exact role of the aqueous humor myocilin protein in the genesis in increased IOP in these primary glaucomatous breeds.

Relationship of cerebral blood flow and central visual function in primary open-angle glaucoma

PURPOSE

To investigate the relations between middle cerebral artery (MCA) blood flow velocities and central visual function measured by foveal cone electroretinograms (ERG) and visual field.

METHODS

Fifteen primary open-angle glaucoma patients were recruited. The eye with the more severe visual field defect (full threshold 24-2) and/or optic disc damage was chosen. Measurements included brachial arterial pressure, heart rate, visual acuity (logMAR), contrast sensitivity (CSV-1000), central visual field (Humphrey SITA 10-2), foveal cone ERG, and transcranial Doppler. Pearson correlation coefficients were estimated to assess the strength of the linear relationship between the MCA flow velocity and the other measured parameters.

RESULTS

Visual field was successfully completed in 12 eyes. We were unable to obtain ERG responses and MCA velocity readings for 1 patient. A significant correlation was observed between MCA mean flow velocity and focal cone ERG amplitude [r=0.69, n=13, confidence interval (CI) 0.22, 0.90, P=0.009], but correlation between mean foveal cone ERG implicit time and middle cerebral was not statistically significant (r=0.011, n=13, CI 0.47, 0.63). A significant correlation was also observed between MCA mean flow velocity and mean sensitivity (r=0.76, n=12, CI 0.32, 0.93, P=0.005), and mean defect (r=0.73, n=12, CI 0.28, 0.92, P=0.007) of the central visual field, logMAR visual acuity (r=0.57, n=14, CI 0.05, 0.84, P=0.036), and contrast sensitivity (r=0.61, n=13, CI 0.09, 0.87, P=0.027).

CONCLUSIONS

Our findings suggest that in certain primary open-angle glaucoma patients diminished central visual function may be one manifestation of widespread cerebrovascular insufficiency.

11beta-hydroxysteroid dehydrogenase type 1: a tissue-specific regulator of glucocorticoid response

11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) interconverts inactive cortisone and active cortisol. Although bidirectional, in vivo it is believed to function as a reductase generating active glucocorticoid at a prereceptor level, enhancing glucocorticoid receptor activation. In this review, we discuss both the genetic and enzymatic characterization of 11beta-HSD1, as well as describing its role in physiology and pathology in a tissue-specific manner. The molecular basis of cortisone reductase deficiency, the putative "11beta-HSD1 knockout state" in humans, has been defined and is caused by intronic mutations in HSD11B1 that decrease gene transcription together with mutations in hexose-6-phosphate dehydrogenase, an endoluminal enzyme that provides reduced nicotinamide-adenine dinucleotide phosphate as cofactor to 11beta-HSD1 to permit reductase activity. We speculate that hexose-6-phosphate dehydrogenase activity and therefore reduced nicotinamide-adenine dinucleotide phosphate supply may be crucial in determining the directionality of 11beta-HSD1 activity. Therapeutic inhibition of 11beta-HSD1 reductase activity in patients with obesity and the metabolic syndrome, as well as in glaucoma and osteoporosis, remains an exciting prospect.

Antiglaucoma eye drop pulses--increased interleukin-6 secretion by Tenon's capsule fibroblast cultures

PURPOSE

Long-term antiglaucoma eye drop therapy prior to trabeculectomy is a risk factor for surgical failure resulting from Tenon's capsule fibrosis at the fistula site. The study tested the hypothesis that secretion of the proinflammatory cytokine interleukin (IL)-6 by wounded Tenon's capsule-fibroblasts is elevated by prior long-term antiglaucoma eye drop treatment.

METHODS

Fibroblast cultures were established from Tenon's capsule biopsies during trabeculectomy. Twice daily and for four and a half days, confluent secondary (2-4 passages) cultures were treated (30 minutes at 37 degrees C) with the following drugs (diluted at 1:400-1:100): 0.2% brimonidine-tartrate (Alphagan), 2.0% dorzolamide-HCl (Trusopt), 0.5% timolol-maleate (Timoptic), 2.0% dorzolamide-HCl/0.5% timolol-maleate (Cosopt), 2 and 4% pilocarpine-HCl (Akarpine and Pilocar), 0.005% latanoprost (Xalatan), placebos for Trusopt and Timoptic, and 0.01% benzalkonium chloride. Subsequently, cultures were wounded by removing cells grown on half of each culture dishes along with the medium and conditioned for 20 hours in serum-free growth medium, which was then collected for ELISA for IL-6 (and TNF-alpha and IL-1 beta). Cultures were grown for four additional days to show the maintenance of culture sterility.

RESULTS

Latanoprost, pilocarpine-HCl, and timolol-maleate increased IL-6 levels in the conditioned medium in a dilution factor-dependent manner (P < 0.05, ANOVA). IL-6 concentrations were increased most significantly by latanoprost and were (pg/ml; mean +/- SEM; N = 3 cultures) 186 +/- 37, 187 +/- 33, 295 +/- 46 and 336 +/- 76 in cultures treated at 1:400, 1:250, 1:150, and 1:100 dilutions, respectively, whereas those of six control cultures averaged 80 +/- 9. Benzalkonium chloride, brimonidine-tartrate, dorzolamide-HCl, Cosopt placebo, Timoptic placebo, and dorzolamide-HCl/timolol-maleate did not significantly elevate IL-6 concentrations. IL-1 beta and TNF-alpha were not detected in the medium of control cultures and those treated with pilocarpine (1:200).

CONCLUSIONS

The present study demonstrated for the first time that the level of IL-6 secretion by wounded Tenon's capsule fibroblast cell cultures was increased by repeat pulsing of these cultures with some, but not all, antiglaucoma eye drops prior to wounding.

Pathophysiologic implications of angiotensin I-converting enzyme as a mechanosensor: diabetes

If somatic angiotensin I-converting enzyme (ACE) were a mechanosensor, as recently claimed, it would provide insight into the molecular origin of most adult diseases, such as diabetes, cancer, autoimmune diseases, and psychiatric disease, as well as aging itself. The "ACE as mechanosensor" hypothesis holds that tissue ACE is activated by turbulent flow with each heart beat, so that age-dependent diseases begin with a signal from the vasculature. Activation of ACE would thus represent the first of many amplification steps ("cascades"), placing it at the origin of most age-dependent diseases. As a corollary, effective inhibition of tissue ACE might significantly delay the progression of most diseases of aging. In this paper we will explore how useful this hypothesis is in explaining the molecular pathogenesis of diabetes and its complications, in which aging is accelerated.