Centre for Eye Research Australia (CERA) - Research Publications
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Human Mitoribosome Biogenesis and Its Emerging Links to Disease
Mammalian mitochondrial ribosomes (mitoribosomes) synthesize a small subset of proteins, which are essential components of the oxidative phosphorylation machinery. Therefore, their function is of fundamental importance to cellular metabolism. The assembly of mitoribosomes is a complex process that progresses through numerous maturation and protein-binding events coordinated by the actions of several assembly factors. Dysregulation of mitoribosome production is increasingly recognized as a contributor to metabolic and neurodegenerative diseases. In recent years, mutations in multiple components of the mitoribosome assembly machinery have been associated with a range of human pathologies, highlighting their importance to cell function and health. Here, we provide a review of our current understanding of mitoribosome biogenesis, highlighting the key factors involved in this process and the growing number of mutations in genes encoding mitoribosomal RNAs, proteins, and assembly factors that lead to human disease.
Renal supportive care, palliative care and end-of-life care: Perceptions of similarities, differences and challenges across Australia and New Zealand
Renal supportive care (RSC) is an approach integrating nephrology and palliative care to improve quality of life for people with chronic kidney disease (CKD). RSC practice varies across services; therefore, understanding clinicians' perspectives is important to the evolution and definition of RSC.
Evaluation of the diagnostic performance of the creatinine-based Chronic Kidney Disease Epidemiology Collaboration equation in people with diabetes: A systematic review
AIMS: GFR estimated with the creatinine-based Chronic Kidney Disease Epidemiology Collaboration (CKD-EPICr ) equation is used to screen for diabetic kidney disease and assess its severity. We systematically reviewed the process and outcome of evaluating CKD-EPICr in estimating point GFR or GFR decline over time in adults with type 1 or type 2 diabetes. METHODS: In this systematic review, MEDLINE, Embase and Cochrane Central Register of Controlled Trials were searched up to August 2019. Observational studies comparing CKD-EPICr with measured GFR (mGFR) in adults with diabetes were included. Studies on people with kidney transplant, non-diabetes related kidney disease, pregnancy, potential kidney donors, and those with critical or other systematic illnesses were excluded. Two independent reviewers extracted data from published papers and disagreements were resolved by consensus. Risk-of-bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. (PROSPERO registration number: CRD42018108776). RESULTS: From the 2820 records identified, 29 studies (14 704 participants) were included. All studies were at risk of bias. Bias (eight different forms) ranged from -26 to 35 ml min-1 1.73 m-2 ; precision (five different forms) ranged between 9 and 63 ml min-1 1.73 m-2 ; accuracy (five different forms) ranged between 16% and 96%; the correlation coefficient between CKD-EPICr and mGFR (four different forms) ranged between 0.38 and 0.86; and the reduced major axis regression slope ranged between 0.8 and 1.8. CONCLUSIONS: Qualitative synthesis of data suggested CKD-EPICr was inaccurate in estimating point GFR or GFR decline over time. Furthermore, a lack of consistency in the methods and processes of evaluating the diagnostic performance of CKD-EPICr limits reliable quantitative assessment. The equation needs to be improved in adults with diabetes.
Infliximab, adalimumab and vedolizumab concentrations across pregnancy and vedolizumab concentrations in infants following intrauterine exposure
Background The impact of pregnancy on levels of biologic agents in patients with IBD is undefined and time to elimination in vedolizumab‐exposed infants is unknown. Aims To determine the effect of pregnancy on infliximab, adalimumab and vedolizumab levels and to study infant vedolizumab clearance Methods In a prospective observational study, maternal drug levels were measured pre‐conception, in each trimester, at delivery and postpartum. The association between drug levels and gestation in weeks was assessed using generalised estimating equation modelling. Infant vedolizumab levels were performed at birth (cord blood), 6 weeks and 3 months or until undetectable. Results We included 50 IBD patients (23 on infliximab, 15 on adalimumab and 12 on vedolizumab) with at least two intrapartum observations, plus 5 patients on vedolizumab with only mother and baby samples at delivery. Modelling showed no change in adalimumab levels, an increase in infliximab levels of 0.16 (95% CI 0.08‐0.24) µg/L/week (P < 0.001) and a decrease of 0.18 (95% CI: −0.33 to −0.02) µg/L/week (P = 0.03) for vedolizumab. In 17 mother‐baby pairs, median infant vedolizumab levels at birth were lower than maternal levels (P < 0.05) with an infant:maternal ratio of 0.7 (IQR 0.5‐0.9). Vedolizumab was undetectable between 15 and 16 weeks of age in all 12 infants completing follow‐up testing. Conclusions During pregnancy, adalimumab levels remain stable, while infliximab levels increase and vedolizumab levels decrease. However, the increments were small suggesting that intrapartum therapeutic drug monitoring and dose adjustment are not indicated. Unlike infliximab and adalimumab, infant vedolizumab levels are lower in cord blood than in mothers and appear to clear rapidly.
Multi-focal electro-retinogram response following sub-threshold nano-second laser intervention in age-related macular degeneration
IMPORTANCE: The effect of sub-threshold nano-second laser (SNL) treatment on retinal function remains unknown. BACKGROUND: SNL treatment has been studied as a potential intervention in intermediate age-related macular degeneration (iAMD). This study investigated the longitudinal effect of SNL treatment on retinal function. DESIGN: This was a sub-study of the LEAD trial; a 36-month, multi-centre, randomized and sham-controlled trial. PARTICIPANTS: Subjects with iAMD. METHODS: Eligible participants were assigned randomly to receive SNL or sham treatment to the study eye at 6-monthly visits. Multi-focal electro-retinography (mfERG) was performed at each study visit from a study site. The mfERG responses were grouped into three regions (central, middle and outer rings) and compared between the SNL and sham group. MAIN OUTCOME MEASURES: mfERG P1 response amplitude and implicit time. RESULTS: Data were collected from 50 subjects (26 in the SNL group, 24 in the sham group). At baseline, the P1 amplitudes of both the study eyes and the fellow eyes were similar between the groups at all rings. In the sham group, the P1 amplitude gradually decreased over time (P < .05). In the SNL group, there was an improvement in P1 amplitude which became statistically significant at the 36-month visit, detected in both the treated and fellow eyes at the central (P = .005) and middle ring (P = .007) but not at the outer ring (P = .070). No difference in P1 implicit time detected between the groups (P > .05). CONCLUSIONS AND RELEVANCE: SNL treatment improved electro-physiological function. mfERG could be useful for monitoring AMD progression and evaluating the efficacy of SNL treatment.
A Survey on Knowledge Gaps in Assessment and Management of Severe Drug Hypersensitivity Reactions: Multicenter Cross-Sectional Study of Australian Health Care Providers
Severe drug hypersensitivity reactions (DHRs) are often encountered by health care professionals (HCPs). We evaluated knowledge of doctors and pharmacists in the assessment and management of severe DHRs using a structured questionnaire. A cross-sectional study was conducted in 4 metropolitan hospital networks in Melbourne, Australia. A 13-question, scenario-based multiple-choice questionnaire to assess specific knowledge domains in drug hypersensitivity syndrome recognition, causality attribution, cross-reactivity patterns, appropriate diagnostic tests, and therapy was administered to HCPs of various vocation and specialty groups. Data were analyzed according to profession, self-reported experience, and preparedness in managing severe DHRs. Two hundred thirty-eight participants (45.0% senior doctors, 24.4% junior doctors, and 30.7% pharmacists) across a range of subspecialties achieved an overall median score of 7 (IQR, 5-8)-overall 55.6% correct responses to all questions-with senior doctors outperforming junior doctors and pharmacists (P < .001). The best performance by all participants was in DHR syndrome recognition (60.9%), and the poorest was in diagnostics/therapy (52.0%). HCP group and experience level were significantly associated with better performance in the knowledge domains of cross-reactivity and diagnostics/therapy (P = .003 and < .001, respectively), but not in the domains of syndrome recognition and causality attribution (P > .05). Levels of self-reported preparedness in DHR management were not associated with performance rates in any of the knowledge domains. This study demonstrated significant knowledge gaps in the recognition and management of severe drug hypersensitivity reactions. Targeted multidisciplinary education of staff caring for these patients is needed to improve knowledge gaps.
Visual impairment in highly myopic eyes: The ZOC-BHVI High Myopia Cohort Study
Importance Understanding visual impairment (VI) under different definitions and potential risk factors in high myopic is important for future myopia control. Background Limited studies exists investigating the VI among high myopic and with varying VI definitions. Design Registry cohort study. Participants Eight hundred and eighty‐four participants were from ZOC‐BHVI study. Methods Subjects aged 7 to 70 years with high myopia were enrolled. Uncorrected visual acuity and best‐corrected visual acuity (UCVA and BCVA), cycloplegic refraction, axial length (AL), corneal curvatures, anterior chamber depth and lens thickness were measured. Axial length/corneal radius of curvature ratio (AL/CR ratio) was calculated. Fundus lesions were graded into five categories. VI and blindness were defined based on the better‐seeing eye according to the World Health Organization (WHO) criteria and US criteria. Multiple logistic regression analysis was used to assess risk factors for VI. Main Outcome Measures Rates of VI and blindness. Results A total of 884 participants were included, with mean (SD) age 18.5 (12.4) years and 46.4% male. Rate of UCVI/blindness were 72.6%/27.3% and 17.9%/82.1% based on WHO and US criteria. With respect to BCVA, 4.1%/5.9% of participants had BCVI using two definitions, whereas the rate for blindness was 0.2% and 0.6%. After adjusting confounders, multiple logistic regression showed that more severe fundus lesions, greater AL/CR ratio were at a higher risk of being VI, both in two definitions (P < .005). Conclusions and Relevance The rate of VI and blindness in highly myopic patients varies significantly using different definition. Severe fundus lesions and greater AL/CR ratios were associated with a higher risk of VI.
Diabetic retinopathy progression 6 months post-cataract surgery with intravitreous bevacizumab vs triamcinolone: A secondary analysis of the DiMECAT trial
IMPORTANCE: Diabetic retinopathy (DR) may progress following cataract surgery due to surgery-induced inflammation. The effect of intravitreal bevacizumab (BVB) and triamcinolone acetonide (TCA), which have differing anti-inflammatory properties, on DR progression following cataract surgery has not been reported. BACKGROUND: To report the progression of DR in diabetic patients undergoing cataract extraction treated with intravitreal BVB or TCA during the surgery. DESIGN: Post hoc analysis of 6-month data from a prospective, randomized, double-masked clinical trial. PARTICIPANTS: Diabetic patients with clinically significant cataract and fovea involving diabetic macular oedema (DME), or a recent history of DME. METHODS: Participants were randomly allocated 1:1 to receive intravitreal BVB 1.25 mg or TCA 4 mg during and post-cataract surgery as needed. The rate of DR progression between groups was compared. MAIN OUTCOME MEASURES: DR progression. RESULTS: There were 61 eyes included. Patients receiving BVB were older than those receiving TCA (70.2 vs 64.3 years; P < .05). Three participants (10.7%) in the BVB and three (9.09%) in the TCA group had a one-step progression, while none in BVB and only one (3%) in the TCA group demonstrated two-step DR progression. In the majority of these patients, DR progression was from mild to moderate non-proliferative diabetic retinopathy. CONCLUSION AND RELEVANCE: In this study, BVB and TCA groups had a similar, and lower rate of DR progression compared to previous studies where no adjunctive treatment was administered, suggesting that patients with DME may benefit from either intraoperative intravitreous BVB or TCA injection to reduce the risk of DR progression following cataract surgery.
Epidemiology of episcleritis and scleritis in urban Australia
IMPORTANCE: The epidemiology of episcleritis and scleritis in Australia is largely unknown. BACKGROUND: To determine the incidence, prevalence and clinical characteristics of episcleritis and scleritis in Melbourne. DESIGN: Retrospective longitudinal study. PARTICIPANTS: Patients aged ≥18 years with episcleritis or scleritis seen at the Royal Victorian Eye and Ear Hospital from November 2014 to October 2015. METHODS: Medical record review confirmed clinical diagnosis and characteristics. Incidence and prevalence were calculated using estimates of the adult population in areas of Melbourne with ≥30 ocular presentations/year to the emergency department. MAIN OUTCOME MEASURES: Diagnosis of active episcleritis or scleritis, aetiology, ocular complications and treatments. RESULTS: From a general population of 3 408 068, we confirmed 149 new and 23 pre-existing cases of active episcleritis, and 35 new and 23 pre-existing cases of active scleritis. Incidence per 100 000 person-years was 4.4 (95% confidence interval [CI] 3.7-5.1) for episcleritis and 1.0 (95% CI 0.7-1.4) for scleritis, while 12-month prevalence was 5.1 (95% CI 4.3-5.9) and 1.7 (1.3-2.2) per 100 000 persons, respectively. Systemic disease was associated with 10% of episcleritis compared with 34% of scleritis (P < .001). Ocular complications were seen in 3% (6/184) of episcleritis eyes and 44% (32/72) of scleritis eyes, with the commonest being anterior uveitis (12/72) and ocular hypertension (14/72). At presentation, scleritis patients were commonly treated with oral non-steroidal anti-inflammatory drugs (60%) and prednisolone (19%). By 12 months, 24% of scleritis patients required immunosuppressants. CONCLUSIONS AND RELEVANCE: Rates of episcleritis and scleritis in our single-centre Australian study were low. Episcleritis was usually benign, whereas scleritis had increased ocular complications and systemic disease.
The genetic and clinical landscape of nanophthalmos and posterior microphthalmos in an Australian cohort
Nanophthalmos and posterior microphthalmos are ocular abnormalities in which both eyes are abnormally small, and typically associated with extreme hyperopia. We recruited 40 individuals from 13 kindreds with nanophthalmos or posterior microphthalmos, with 12 probands subjected to exome sequencing. Nine probands (69.2%) were assigned a genetic diagnosis, with variants in MYRF, TMEM98, MFRP, and PRSS56. Two of four PRSS56 families harbored the previously described c.1066dupC variant implicated in over half of all reported PRSS56 kindreds, with different surrounding haplotypes in each family suggesting a mutational hotspot. Individuals with a genetic diagnosis had shorter mean axial lengths and higher hyperopia than those without, with recessive forms associated with the most extreme phenotypes. These findings detail the genetic architecture of nanophthalmos and posterior microphthalmos in a cohort of predominantly European ancestry, their relative clinical phenotypes, and highlight the shared genetic architecture of rare and common disorders of refractive error.
Plurality in multi-disciplinary research: multiple institutional affiliations are associated with increased citations
(PEERJ INC, 2018-09-24)
Background: The institutional affiliations and associated collaborative networks that scientists foster during their research careers are salient in the production of high-quality science. The phenomenon of multiple institutional affiliations and its relationship to research output remains relatively unexplored in the literature. Methods: We examined 27,612 scientific articles, modelling the normalized citation counts received against the number of authors and affiliations held. Results: In agreement with previous research, we found that teamwork is an important factor in high impact papers, with average citations received increasing concordant with the number of co-authors listed. For articles with more than five co-authors, we noted an increase in average citations received when authors with more than one institutional affiliation contributed to the research. Discussion: Multiple author affiliations may play a positive role in the production of high-impact science. This increased researcher mobility should be viewed by institutional boards as meritorious in the pursuit of scientific discovery.
Genomic locus modulating corneal thickness in the mouse identifies POU6F2 as a potential risk of developing glaucoma.
(Public Library of Science (PLoS), 2018-01)
Central corneal thickness (CCT) is one of the most heritable ocular traits and it is also a phenotypic risk factor for primary open angle glaucoma (POAG). The present study uses the BXD Recombinant Inbred (RI) strains to identify novel quantitative trait loci (QTLs) modulating CCT in the mouse with the potential of identifying a molecular link between CCT and risk of developing POAG. The BXD RI strain set was used to define mammalian genomic loci modulating CCT, with a total of 818 corneas measured from 61 BXD RI strains (between 60-100 days of age). The mice were anesthetized and the eyes were positioned in front of the lens of the Phoenix Micron IV Image-Guided OCT system or the Bioptigen OCT system. CCT data for each strain was averaged and used to QTLs modulating this phenotype using the bioinformatics tools on GeneNetwork (www.genenetwork.org). The candidate genes and genomic loci identified in the mouse were then directly compared with the summary data from a human POAG genome wide association study (NEIGHBORHOOD) to determine if any genomic elements modulating mouse CCT are also risk factors for POAG.This analysis revealed one significant QTL on Chr 13 and a suggestive QTL on Chr 7. The significant locus on Chr 13 (13 to 19 Mb) was examined further to define candidate genes modulating this eye phenotype. For the Chr 13 QTL in the mouse, only one gene in the region (Pou6f2) contained nonsynonymous SNPs. Of these five nonsynonymous SNPs in Pou6f2, two resulted in changes in the amino acid proline which could result in altered secondary structure affecting protein function. The 7 Mb region under the mouse Chr 13 peak distributes over 2 chromosomes in the human: Chr 1 and Chr 7. These genomic loci were examined in the NEIGHBORHOOD database to determine if they are potential risk factors for human glaucoma identified using meta-data from human GWAS. The top 50 hits all resided within one gene (POU6F2), with the highest significance level of p = 10-6 for SNP rs76319873. POU6F2 is found in retinal ganglion cells and in corneal limbal stem cells. To test the effect of POU6F2 on CCT we examined the corneas of a Pou6f2-null mice and the corneas were thinner than those of wild-type littermates. In addition, these POU6F2 RGCs die early in the DBA/2J model of glaucoma than most RGCs. Using a mouse genetic reference panel, we identified a transcription factor, Pou6f2, that modulates CCT in the mouse. POU6F2 is also found in a subset of retinal ganglion cells and these RGCs are sensitive to injury.