Retinal and Choroidal Thickness in an Indigenous Population from Ghana: Comparison with Individuals with European or African Ancestry

Purpose

To evaluate the thickness of the macular retina and central choroid in an indigenous population from Ghana, Africa and to compare them with those measured among individuals with European or African ancestry.

Design

Cross-sectional study, systematic review, and meta-analyses.

Participants

Forty-two healthy Ghanaians, 37 healthy individuals with European ancestry, and an additional 1427 healthy subjects with African ancestry from previously published studies.

Methods

Macular retinal thickness in the fovea, parafovea, and perifovea and central choroidal thickness were extracted from OCT volume scans. Associations with ethnicity, age, and sex were assessed using mixed-effect regression models. Monte Carlo simulations were performed to determine the sensitivity of significant associations to additional potential confounders. Pooled estimates of retinal thickness among other groups with African ancestry were generated through systematic review and meta-analyses.

Main Outcome Measures

Macular retinal thickness and central choroidal thickness and their association with ethnicity, age, and sex.

Results

When adjusted for age and sex, the macular retina and central choroid of Ghanaians are significantly thinner as compared with subjects with European ancestry (P < 0.001). A reduction in retinal and choroidal thickness is observed with age, although this effect is independent of ethnicity. Meta-analyses indicate that retinal thickness among Ghanaians differs markedly from that of African Americans and other previously reported indigenous African populations.

Conclusions

The thickness of the retina among Ghanaians differs not only from those measured among individuals with European ancestry, but also from those obtained from African Americans. Normative retinal and choroidal parameters determined among individuals with African or European ancestry may not be sufficient to describe indigenous African populations.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Vitreomacular interface abnormalities in the Ghanaian African

BACKGROUND/OBJECTIVE

Describe vitreomacular interface abnormalities (VMIA) using spectral-domain optical coherence tomography (SD-OCT), and correlations with age-related macular degeneration (AMD) grade in Ghanaian Africans.

SUBJECTS/METHODS

Prospective, cross-sectional study of adults aged ≥50 years recruited in Ghana AMD Study. Participant demographics, medical histories, ophthalmic examination, digital colour fundus photography (CFP) were obtained. High-resolution five-line raster OCT, Macular Cube 512 × 128 scans, and additional line scans in areas of clinical abnormality, were acquired. SD-OCT VMI features classified by International Vitreomacular Traction Study Group system and relationships to AMD grade were evaluated.

OUTCOMES

VMIA prevalence, posterior vitreous detachment (PVD), vitreomacular adhesions (VMA), vitreomacular traction (VMT), epiretinal membranes (ERM), correlations with AMD grade.

RESULTS

The full Ghana AMD cohort included 718 participants; 624 participants (1248 eyes) aged ≥50 years (range = 50-101, mean = 68.8), 68.9% female were included in this analysis. CFP with OCT scans were available for 776 eyes (397 participants); 707 (91.1%) had gradable CFP and OCT scans for both AMD and VMI grading forming the dataset for this report. PVD was absent in 504 (71.3%); partial and complete PVD occurred in 16.7% and 12.0% respectively. PVD did not increase with age (p = 0.720). VMIA without traction and macular holes were observed in 12.2% of eyes; 87.8% had no abnormalities. VMIA was not significantly correlated with AMD grade (p = 0.819).

CONCLUSIONS

This provides the first assessment of VMIA in Ghanaian Africans. VMIA are common in Africans; PVD may be less common than in Caucasians. There was no significant association of AMD grade with VMIA.

Usher Syndrome on the Island of Ireland: A Genotype-Phenotype Review

Purpose

Usher syndrome (USH) is a genetically heterogeneous group of autosomal recessive (AR) syndromic inherited retinal degenerations (IRDs) representing 50% of deaf-blindness. All subtypes include retinitis pigmentosa, sensorineural hearing loss, and vestibular abnormalities. Thorough phenotyping may facilitate genetic diagnosis and intervention. Here we report the clinical/genetic features of an Irish USH cohort.

Methods

USH patients were selected from the Irish IRD registry (Target 5000). Patients were examined clinically (deep-phenotyping) and genetically using a 254 IRD-associated gene target capture sequencing panel, USH2A exon, and whole genome sequencing.

Results

The study identified 145 patients (24.1% USH1 [n = 35], 73.8% USH2 [n = 107], 1.4% USH3 [n = 2], and 0.7% USH4 [n = 1]). A genetic diagnosis was reached in 82.1%, the majority (80.7%) being MYO7A or USH2A genotypes. Mean visual acuity and visual field (VF) were 0.47 ± 0.58 LogMAR and 31.3° ± 32.8°, respectively, at a mean age of 43 years. Legal blindness criteria were met in 40.7%. Cataract was present in 77.4%. ADGRV1 genotypes had the most VF loss, whereas USH2A patients had greater myopia and CDH23 had the most astigmatism. Variants absent from gnomAD non-Finnish Europeans and ClinVar represented more than 20% of the variants identified and were detected in ADGRV1, ARSG, CDH23, MYO7A, and USH2A.

Conclusions

USH is a genetically diverse group of AR IRDs that have a profound impact on affected individuals and their families. The prevalence and phenotype/genotype characteristics of USH in Ireland have, as yet, gone unreported. Understanding the genotype of Irish USH patients may guide clinical and genetic characterization facilitating access to existing/novel therapeutics.

Detailed analysis of an enriched deep intronic ABCA4 variant in Irish Stargardt disease patients

Over 15% of probands in a large cohort of more than 1500 inherited retinal degeneration patients present with a clinical diagnosis of Stargardt disease (STGD1), a recessive form of macular dystrophy caused by biallelic variants in the ABCA4 gene. Participants were clinically examined and underwent either target capture sequencing of the exons and some pathogenic intronic regions of ABCA4, sequencing of the entire ABCA4 gene or whole genome sequencing. ABCA4 c.4539 + 2028C > T, p.[= ,Arg1514Leufs*36] is a pathogenic deep intronic variant that results in a retina-specific 345-nucleotide pseudoexon inclusion. Through analysis of the Irish STGD1 cohort, 25 individuals across 18 pedigrees harbour ABCA4 c.4539 + 2028C > T and another pathogenic variant. This includes, to the best of our knowledge, the only two homozygous patients identified to date. This provides important evidence of variant pathogenicity for this deep intronic variant, highlighting the value of homozygotes for variant interpretation. 15 other heterozygous incidents of this variant in patients have been reported globally, indicating significant enrichment in the Irish population. We provide detailed genetic and clinical characterization of these patients, illustrating that ABCA4 c.4539 + 2028C > T is a variant of mild to intermediate severity. These results have important implications for unresolved STGD1 patients globally with approximately 10% of the population in some western countries claiming Irish heritage. This study exemplifies that detection and characterization of founder variants is a diagnostic imperative.

The human embryonic genome is karyotypically complex, with chromosomally abnormal cells preferentially located away from the developing fetus

STUDY QUESTION

Are chromosome abnormalities detected at Day 3 post-fertilization predominantly retained in structures of the blastocyst other than the inner cell mass (ICM), where chromosomally normal cells are preferentially retained?

SUMMARY ANSWER

In human embryos, aneuploid cells are sequestered away from the ICM, partly to the trophectoderm (TE) but more significantly to the blastocoel fluid within the blastocoel cavity (Bc) and to peripheral cells (PCs) surrounding the blastocyst during Day 3 to Day 5 progression.

WHAT IS KNOWN ALREADY

A commonly held dogma in all diploid eukaryotes is that two gametes, each with 'n' chromosomes (23 in humans), fuse to form a '2n' zygote (46 in humans); a state that remains in perpetuity for all somatic cell divisions. Human embryos, however, display high levels of chromosomal aneuploidy in early stages that reportedly declines from Day 3 (cleavage stage) to Day 5 (blastocyst) post-fertilization. While this observation may be partly because of aneuploid embryonic arrest before blastulation, it could also be due to embryo 'normalization' to a euploid state during blastulation. If and how this normalization occurs requires further investigation.

STUDY DESIGN, SIZE, DURATION

A total of 964 cleavage-stage (Day 3) embryos underwent single-cell biopsy and diagnosis for chromosome constitution. All were maintained in culture, assessing blastulation rate, both for those assessed euploid and aneuploid. Pregnancy rate was assessed for those determined euploid, blastulated and subsequently transferred. For those determined aneuploid and blastulated (174 embryos), ICM (all 174 embryos), TE (all 174), Bc (47 embryos) and PC (38 embryos) were analyzed for chromosome constitution. Specifically, concordance with the original Day 3 diagnosis and determination if any 'normalized' to euploid karyotypes within all four structures was assessed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All patients (144 couples) were undergoing routine preimplantation genetic testing for aneuploidy in three IVF clinical settings. Cleavage-stage biopsy preceded chromosome analysis by next-generation sequencing. All patients provided informed consent. Additional molecular testing was carried out on blastocyst embryos and was analyzed for up to four embryonic structures (ICM, TE, Bc and PC).

MAIN RESULTS AND THE ROLE OF CHANCE

Of 463/964 embryos (48%) diagnosed as euploid at Day 3, 70% blastulated (leading to a 59% pregnancy rate) and 30% degenerated. Conversely, of the 501 (52%) diagnosed as aneuploid, 65% degenerated and 35% (174) blastulated, a highly significant difference (P < 0.0001). Of the 174 that blastulated, the ratio of '(semi)concordant-aneuploid' versus 'normalized-euploid' versus 'other-aneuploid' embryos was, respectively, 39%/57%/3% in the ICM; 49%/48%/3% in the TE; 78%/21%/0% in the PC; and 83%/10%/5% in the Bc. The TE karyotype therefore has a positive predictive value of 86.7% in determining that of the ICM, albeit with marginally higher aneuploid rates of abnormalities (P = .071). Levels of abnormality in Bc/PC were significantly higher (P < 0.0001) versus the ploidy of the ICM and TE and nearly all chromosome abnormalities were (at least partially) concordant with Day 3 diagnoses.

LIMITATIONS, REASONS FOR CAUTION

The results only pertain to human IVF embryos so extrapolation to the in vivo situation and to other species is not certain. We acknowledge (rather than lineage-specific survival, as we suggest here) the possibility of other mechanisms, such as lineage-specific movement of cells, during blastulation. Ethical considerations, however, make investigating this mechanism difficult on human embryos.

WIDER IMPLICATIONS OF THE FINDINGS

Mosaic human cleavage-stage embryos can differentiate into a euploid ICM where euploid cell populations predominate. Sequestering of aneuploid cells/nuclei to structures no longer involved in fetal development has important implications for preimplantation and prenatal genetic testing. These results also challenge previous fundamental understandings of mitotic fidelity in early human development and indicate a complex and fluid nature of the human embryonic genome.

STUDY FUNDING/COMPETING INTEREST(S)

This research was funded by Organon Pharmaceuticals and Merck Serono by grants to W.G.K. W.G.K. is also an employee of AdvaGenix, who could, potentially, indirectly benefit financially from publication of this manuscript. R.C.M. is supported by the National Institute of General Medical Sciences of the National Institutes of Health under award number R35GM133747. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. D.K.G. provides paid consultancy services for Care Fertility.

TRIAL REGISTRATION NUMBER

: N/A.

Ocular sarcoidosis prevalence and clinical features in the Northern Ireland population

BACKGROUND/OBJECTIVES

To record the prevalence of ocular sarcoidosis (OS) cases present in Northern Ireland as diagnosed using the International Workshop on Ocular Sarcoidosis (IWOS) classification, 2019. There are currently no data regarding OS in this population.

SUBJECTS/METHODS

Retrospective case review of OS cases as identified by IWOS criteria 2019. Mid-year population estimates were used to calculate disease prevalence. Additional data collected included uveitis features, ocular complications and the presence of ocular only or multi-system disease.

RESULTS

A total of 86 patients were identified meeting the criteria for a diagnosis of OS, and the prevalence of OS in Northern Ireland was estimated to be 4.5 cases per 100,000. The most common type of uveitis was panuveitis in 36% of cases, and the most common ocular complication was ocular hypertension in 36% of cases and detectable glaucomatous changes in 10%. Overall, 80% of cases presenting with ocular only sarcoidosis subsequently developed second organ involvement at a rate of 14%/person-years. The most common extra-ocular site of sarcoidosis was pulmonary.

CONCLUSIONS

The Northern Ireland population has a relatively high prevalence of OS compared with other European countries. OS presenting with only ocular involvement progressed to second organ involvement in 80% of patients at a rate of 14%/person-years. Raised intra-ocular pressure with or without glaucomatous damage was a frequent finding. Thoracic CT imaging should be requested if clinical suspicion of OS exists and the presence of lymphopenia has utility in diagnosis with concurrent use of systemic ACE inhibitors.

Characterization of West African Crystalline Macular Dystrophy in the Ghanaian Population

OBJECTIVE/PURPOSE

West African Crystalline Maculopathy (WACM) is characterized by the presence of macular hyper-refractile crystal-like deposits. Although the underlying pathophysiology has not been elucidated, a few biological drivers have been proposed. We analysed a large WACM case series to gain a more robust understanding of its features and etiology.

DESIGN

Prospective, Cross-sectional cohort study.

SUBJECTS/PARTICIPANTS

Participants with WACM were selected from the large cohort recruited into the Ghana Age-Related Macular Degeneration Study (Ghana AMD Study).

METHODS

Demographic and detailed medical histories, full ophthalmic examinations, digital colour fundus photographs and optical coherence tomography (OCT) images were obtained. All WACM cases were evaluated by three retina experts. Crystal numbers, location, and distribution were determined. Associations between WACM and Caucasian AMD risk variants were assessed using Firth's bias-reduced logistic regression, including age and gender as covariates.

MAIN OUTCOME MEASURES

Phenotypic features of, and genetic associations with, WACM.

RESULTS

WACM was identified in 106 eyes of 53 participants: 22 were bilateral and 24 unilateral. Grading for AMD was not possible in one eye of seven WACM participants; therefore, laterality was not assessed in these subjects. Thirty-eight participants were female, and 14 male; gender was unrecorded for one participant. Mean age was 68.4 years (range 45-101). OCT demonstrated typical WACM crystals, which were more easily identified at high contrast and predominantly located at the inner limiting membrane (ILM). In eyes with co-pathology, crystals localised deeper in the inner retina with wider retinal distribution over co-pathology lesions. There was no age or gender association. A significant association was observed between the complement factor H (CFH) 402H risk variant and WACM.

CONCLUSION

This study confirms localization of crystals adjacent to the ILM, and distribution over lesions in eyes with co-pathology. Evaluation of OCT images under high contrast allows improved identification. WACM may be associated with the CFH-CFHR5 AMD-risk locus identified amongst Caucasians; however, it is also possible that combination of crystals and the CFH 402H allele increases the risk for developing late AMD. Further analyses using larger sample sizes are warranted to identify causalities between genotype and WACM phenotype.

Surgical planning during a pandemic: Identifying patients at high risk of severe disease or death due to COVID-19 in a cohort of patients on a cataract surgery waiting list

BACKGROUND

The delivery of cataract surgery during the COVID-19 pandemic is challenging because of the risk of nosocomial SARS-CoV-2 infection when patients attend hospital for elective care. In order to ascertain the risk to patients awaiting cataract surgery, this study aimed to identify the presence of systemic comorbidities that are associated with a high risk of severe disease or death due to COVID-19.

METHODS

A prospective study of 315 patients (630 eyes) was conducted from 3^rd June to 31^st July 2020. An electronic health record was used to identify any systemic comorbidities that would render a patient 'clinically extremely vulnerable' to COVID-19, as outlined by the Department of Health for Northern Ireland. Patient demographics, best-corrected visual acuity (VA) and risk of postoperative anisometropia were also recorded.

RESULTS

The median age of patients awaiting cataract surgery was 76 years (range 22-97). Of the 315 patients, 72% were aged over 70 and 16% were aged over 85. A systemic comorbidity that would confer high risk status was identified in 21% of patients. This high risk status was attributable to severe respiratory disease, cancer, and immunosuppression therapies in the majority of cases. The high risk group were younger than those deemed non-high risk, but there were no significant differences with respect to gender, anticipated degree of surgical difficulty, VA, or whether the patient was undergoing first or second eye surgery. Of those patients awaiting first eye cataract surgery, the mean VA in the listed eye was 0.84 logMAR and 39% (70/179) had a VA <0.3 logMAR (6/12 Snellen acuity) in their fellow eye. 57% of patients were awaiting first eye surgery, and 32% of those patients would be at risk of symptomatic anisometropia postoperatively.

CONCLUSION

One-fifth of patients awaiting cataract surgery were found to be at high risk of severe disease or death from COVID-19 and these patients may experience delays in their surgical care. Additional planning is required in order to minimise the morbidity associated with delayed cataract surgery.

Tubulointerstitial nephritis and uveitis in Northern Ireland

Objectives

This paper looks at patients with a diagnosis of tubulointerstitial nephritis and uveitis (TINU) presenting to the Northern Ireland regional adult and paediatric uveitis service in the Belfast Health and Social Care Trust. The demographic distribution, treatment required and the visual and renal outcomes of these patients are documented.

Methods

Data were collected retrospectively on 24 patients with TINU using the Northern Ireland Electronic Care Record, central pathology records alongside the adult and paediatric uveitis databases from 2011 to 2021. Patients were categorised into two groups using the Mandeville classification system. Standard Uveitis Nomenclature (SUN) was used to classify the uveitis.

Results

The population prevalence is at least 12.6 cases per million based on a population of 1.9 million. Nineteen of 24 cases were definite TINU and five of 24 probable. Seventeen out of 24 had biopsy-positive TIN, all of which met all of the Mandeville clinical diagnostic features required for a definite diagnosis. All but one presented with acute bilateral anterior uveitis. The paediatric cases ranged from age 12 to 18 at age of onset with a mean age of 14. Of the 18 adult onset cases, the age ranged from 20 to 76 years. The mean age of onset for the adult cases was 53 years. Of these patients 71% were female; 42% required second-line immunosuppression for ocular disease. Visual acuity was maintained. Follow-up time ranged from 3 months to 16 years. No patient developed long-term renal impairment.

Conclusions

TINU is a cause of uveitis in both the paediatric and adult populations. In Northern Ireland average age with TINU was older than much of the published literature. Long-term immunosuppression for uveitis may be required as ongoing ocular, rather than renal inflammation seemed to require treatment.

Target 5000: a standardized all-Ireland pathway for the diagnosis and management of inherited retinal degenerations

Introduction

Inherited retinal degenerations (IRD) are rare genetic disorders with > 300 known genetic loci, manifesting variably progressive visual dysfunction. IRDs were historically underserved due to lack of effective interventions. Many novel therapies will require accurate diagnosis (phenotype and genotype), thus an efficient and effective pathway for assessment and management is required.

Methods

Using surveys of existing practice patterns and advice from international experts, an all-Ireland IRD service (Target 5000) was designed. Detailed phenotyping was followed by next generation genetic sequencing in both a research and accredited laboratory. Unresolved pedigrees underwent further studies (whole gene/whole exome/whole genome sequencing). Novel variants were interrogated for pathogenicity (cascade screening, in silico analysis, functional studies). A multidisciplinary team (MDT; ophthalmologists, physicians, geneticists, genetic counsellors) reconciled phenotype with genotype. A bespoke care plan was created for each patient comprising supports, existing interventions, and novel therapies/clinical trials.

Results and discussion

Prior to Target 5000, a significant cohort of patients were not engaged with healthcare/support services due to lack of effective interventions. Pathogenic or likely pathogenic variants in IRD-associated genes were detected in 62.3%, with 11.6% having variants of unknown significance. The genotyping arm of Target 5000 allowed a 42.73% cost saving over independent testing, plus the value of MDT expertise/processing. Partial funding has transferred from charitable sources to government resources.

Conclusion

Target 5000 demonstrates efficacious and efficient clinical/genetic diagnosis, while discovering novel IRD-implicated genes/variants and investigating mechanisms of disease and avenues of intervention. This model could be used to develop similar IRD programmes in small/medium-sized nations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01841-1.

Pathogenic alleles in microtubule, secretory granule and extracellular matrix-related genes in familial keratoconus

Keratoconus is a common corneal defect with a complex genetic basis. By whole exome sequencing of affected members from 11 multiplex families of European ancestry, we identified 23 rare, heterozygous, potentially pathogenic variants in 8 genes. These include nonsynonymous single amino acid substitutions in HSPG2, EML6 and CENPF in two families each, and in NBEAL2, LRP1B, PIK3CG and MRGPRD in three families each; ITGAX had nonsynonymous single amino acid substitutions in two families and an indel with a base substitution producing a nonsense allele in the third family. Only HSPG2, EML6 and CENPF have been associated with ocular phenotypes previously. With the exception of MRGPRD and ITGAX, we detected the transcript and encoded protein of the remaining genes in the cornea and corneal cell cultures. Cultured stromal cells showed cytoplasmic punctate staining of NBEAL2, staining of the fibrillar cytoskeletal network by EML6, while CENPF localized to the basal body of primary cilia. We inhibited the expression of HSPG2, EML6, NBEAL2 and CENPF in stromal cell cultures and assayed for the expression of COL1A1 as a readout of corneal matrix production. An upregulation in COL1A1 after siRNA inhibition indicated their functional link to stromal cell biology. For ITGAX, encoding a leukocyte integrin, we assayed its level in the sera of 3 affected families compared with 10 unrelated controls to detect an increase in all affecteds. Our study identified genes that regulate the cytoskeleton, protein trafficking and secretion, barrier tissue function and response to injury and inflammation, as being relevant to keratoconus.

Plasma level of lipocalin 2 is increased in neovascular age-related macular degeneration patients, particularly those with macular fibrosis

Background

Previously, we and others have reported higher populations of circulating neutrophils in patients with neovascular age-related macular degeneration (nAMD). Neutrophil gelatinase-associated lipocalin (NGAL, also known as lipocalin-2, LCN2), an important innate immune mediator, is known to be critically involved in sterile inflammation-mediated organ failure, fibrosis, cancer progression and retinal degeneration. This study investigated the plasma levels of LCN2, matrix metalloproteinase 9 (MMP9) and LCN2/MMP9 complex in different types of nAMD and examined whether the levels were related to patients’ responsiveness to anti-VEGF therapy.

Results

One hundred and seventy-four nAMD patients, including 108 with choroidal neovascularisation (CNV), 32 with retinal angiomatous proliferation (RAP), 23 with polypoidal choroidal vasculopathy (PCV) and 11 unclassified patients, and 43 healthy controls were recruited to this case-control study. Fifty-eight nAMD patients had macular fibrosis and 110 patients did not. Out of the 174 nAMD patients, 80 patients responded completely, 90 responded partially, and 4 did not respond to the anti-VEGF therapy. The plasma levels of LCN2 in nAMD patients (181.46 ± 73.62 ng/ml) was significantly higher than that in healthy controls (152.24 ± 49.55 ng/ml, P = 0.047). However, the difference disappeared after adjusting for age. A positive correlation between plasma level of LCN2 and age was observed in nAMD patients (r = 0.29, P = 0.0002) but not in healthy controls. The plasma level of LCN2 was also positively correlated with circulating neutrophils in nAMD patients (r = 0.34, p = 0.0007) but not in healthy controls (r = 0.057, p = 0.77). No correlation was observed between age and circulating neutrophils. Further analysis of nAMD subtypes uncovered a significantly higher level of LCN2 in patients with macular fibrosis even after adjusting for age. No relationship was observed between plasma levels of LCN2 and patients’ responsiveness to anti-VEGF therapy. The plasma levels of MMP9 and LCN2/MMP9 complex were comparable between nAMD and controls.

Conclusions

Our results suggest that higher plasma levels of LCN2 in nAMD are related to ageing and increased population of circulating neutrophils. Our results also suggest that higher levels of LCN2 may increase the risk of macular fibrosis in nAMD.

COVID-19: The regional impact of COVID-19 on the certification of vision impairment in Northern Ireland

PURPOSE

In this paper we highlight the impact which the disruption of secondary care ophthalmic services, resulting from COVID-19, has had on Sight Impairment (SI) and Severe Sight Impairment (SSI) certification in Northern Ireland.

METHODS

Regional data on SI and SSI certification in the period after the onset of the lockdown (19 March 2020-18 June 2020) were compared to the period immediately before lockdown (1 January 2020-18 March 2020) and to the same periods in 2019. Change documented was compared to post-lockdown reductions in primary and secondary ophthalmic care activity.

RESULTS

In 2019, during the 3-month period (19 March 2019-18 June 2019), 115 individuals were certified as sight impaired (SI 36, SSI 75, unspecified 4). Of those certified, 65 were female, 49 male. Principal causes of certification were: Age-related macular degeneration (AMD) (N = 45), glaucoma (N = 20) and diabetic eye disease (DED) (N = 10). Mean VA, recorded from the better eye of those certified, was 0.96 LogMAR. In the 3 months following the onset of lockdown (19 March 2020-18 June 2020), only 37 individuals were certified (SI 6, SSI 31), 12 female and 25 male. AMD was the most frequent cause of sight impairment (N = 20). There were only two DED certifications and one due to glaucoma. Mean VA in the better eye of those certified was 1.15LogMAR. The numbers of CVI certifications completed following the introduction of COVID-19 lockdown fell by 68%, compared to the 2019 data. There was a significant reduction in the proportion of female certifications (p = 0.01), and in certifications due to glaucoma (p = 0.02). The proportion of those certified as SSI as opposed to SI in the period after the onset of lockdown rose from 68% in 2019 to 84% in 2020. The mean VA of those certified in the period after the onset of lockdown, when compared to those certified in the other three periods, was worse by between 0.21 and 0.19 LogMAR (p = 0.06). Reductions reflected change in overall primary and secondary ophthalmic care activity.

CONCLUSIONS

It is inconceivable that COVID-19 has reduced the incidence of sight-threatening eye disease. We must therefore assume that a flood of newly presenting sight loss will present once the pandemic has passed. New presentations will include those who would normally have attended during the lockdown period, and patients who, had they accessed ophthalmic care at the appropriate time, would have been saved from severe levels of blindness. The implications of the predicted increase in demand for medical, social and low vision related services are huge.

Comparison of the Morphology of the Foveal Pit Between African and Caucasian Populations

Purpose

The purpose of this study was to characterize foveal pit morphology in an African (Ghanaian) population, to compare it to that of a Caucasian group and to determine if it varied with age in the two populations.

Methods

The depth, diameter, slope, and volume of the foveal pit were interpolated from optical coherence tomography volume scans recorded in 84 Ghanaian and 37 Caucasian individuals. Their association with age, sex, and ethnicity was investigated using multilevel regression models.

Results

The foveal pit differed significantly in width, slope, and volume between Ghanaian men and women (P < 0.001), but only in width and volume between Caucasian men and women (P < 0.01). In Ghanaians, age was associated with a narrowing of the foveal depression and a reduction of its volume. Overall, these changes were more pronounced in women as compared to men and were largely absent from the Caucasian group. When controlled for age, the foveal pit of Ghanaians was significantly wider and larger in volume as compared to the Caucasian group (P < 0.001).

Conclusions

The morphology of the foveal pit differs between African and Caucasian individuals. These anatomic differences should be considered when examining differences in prevalence and clinical features of vitreoretinal disorders involving the fovea between the two populations.

Translational Relevance

Differences in retinal anatomy may partly explain variations in the prevalence and clinical features of retinal diseases between Africans and Caucasians. Such differences should be adequately considered in diagnoses and monitoring of ocular diseases in patients with African ancestry.

Findings from a Genotyping Study of Over 1000 People with Inherited Retinal Disorders in Ireland

The Irish national registry for inherited retinal degenerations (Target 5000) is a clinical and scientific program to identify individuals in Ireland with inherited retinal disorders and to attempt to ascertain the genetic cause underlying the disease pathology. Potential participants first undergo a clinical assessment, which includes clinical history and analysis with multimodal retinal imaging, electrophysiology, and visual field testing. If suitable for recruitment, a sample is taken and used for genetic analysis. Genetic analysis is conducted by use of a retinal gene panel target capture sequencing approach. With over 1000 participants from 710 pedigrees now screened, there is a positive candidate variant detection rate of approximately 70% (495/710). Where an autosomal recessive inheritance pattern is observed, an additional 9% (64/710) of probands have tested positive for a single candidate variant. Many novel variants have also been detected as part of this endeavor. The target capture approach is an economic and effective means of screening patients with inherited retinal disorders. Despite the advances in sequencing technology and the ever-decreasing associated processing costs, target capture remains an attractive option as the data produced is easily processed, analyzed, and stored compared to more comprehensive methods. However, with decreasing costs of whole genome and whole exome sequencing, the focus will likely move towards these methods for more comprehensive data generation.

Evaluation of long-term intravitreal anti-vascular endothelial growth factor injections on renal function in patients with and without diabetic kidney disease

Background

Administering anti-vascular endothelial growth factor (anti-VEGF) by intraocular injection has been shown to have a safe systemic profile. Nevertheless, incidents of acute kidney injury following anti-VEGF injection have been reported. We assessed the long-term effect of multiple intravitreal anti-VEGF injections on measures of renal function in patients with diabetes including rate of change of estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (ACR).

Methods

A retrospective review of patients receiving diabetic macular oedema (DMO) treatment was undertaken. Serum creatinine, ACR, number of intravitreal anti-VEGF injections and clinical characteristics were collected from electronic healthcare records (EHR). A co-efficient of eGFR and ACR change with time was calculated over a mean duration of 2.6 years. Regression modelling was used to assess variation in the number of anti-VEGF injections and change in eGFR and ACR.

Results

The EHR of 85 patients with DMO (59% male, 78% type 2 diabetes mellitus [T2DM]) were reviewed. On average, 26.8 intravitreal anti-VEGF injections were given per patient over a mean duration of 31 months. No association between increasing number of anti-VEGF injections and rate of eGFR decline (beta = 0.04, 95% confidence intervals [CI]: − 0.02, 0.09; p = 0.22) or ACR change over time (beta = 0.02, CI: − 0.19, 0.23; p = 0.86) was detected, following adjustment for hypertension, cerebrovascular disease, T2DM, and medications taken.

Conclusion

Our data suggests regular long-term intravitreal VEGF inhibition does not significantly alter the rate of change in eGFR and/or ACR with increasing number of treatment injections.

Serum xanthophyll carotenoids are associated with estimated glomerular filtration rate in an aged cohort

Progressive renal decline is associated with increasing oxidative stress. However, the majority of studies have investigated endogenous antioxidants in predominantly advanced stages of kidney disease. Many traditional risk factors associated with renal dysfunction have been linked with cognitive decline as the kidneys and brain share comparable anatomic and haemodynamic characteristics that leave them susceptible to common pathogenic mechanisms. The objective of this study was to examine serum dietary antioxidants and their association with renal function characterised by estimated glomerular filtration rate (eGFR) in a cross-sectional analysis of 570 participants. High performance liquid chromatography quantified serum levels of retinol, α-tocopherol, γ-tocopherol and six carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene and zeaxanthin) in participants. Multiple regression analyses were used to evaluate associations while adjusting for potential confounders. A sensitivity analysis was performed in cognitively-intact participants only. Serum levels of the xanthophyll carotenoid lutein were positively associated with eGFR in analyses adjusted for age (years), gender, smoking, APOE4 status and Alzheimer’s disease. Retinol was inversely associated with eGFR, although was no longer significant in the smaller sensitivity analysis. Our findings identify significant associations between the xanthophyll carotenoids and eGFR. Further investigations are required to confirm these findings.

The complex phenotype of spinocerebellar ataxia type 48 in eight unrelated Italian families

BACKGROUND AND PURPOSE

Heterozygous mutations in the STUB1 gene have recently been associated with an autosomal dominant form of spinocerebellar ataxia (SCA) associated with cerebellar cognitive-affective syndrome (CCAS), named SCA48.

METHODS

Molecular screening was performed in a cohort of 235 unrelated patients with adult-onset, autosomal dominant (17) or sporadic (218) cerebellar ataxia, negative for pathological trinucleotide expansions in the common SCAs, FRDA and FXTAS loci, by using targeted multigene panels or whole-exome sequencing. Bioinformatics analyses, detailed neurological phenotyping and family segregation studies corroborated the pathogenicity of the novel STUB1 mutations. Clinico-diagnostic findings were reviewed to define the phenotypic spectrum.

RESULTS

Eight heterozygous STUB1 mutations were identified, six of which were novel in 11 patients from eight index families, giving an estimated overall frequency of 3.4% (8/235) for SCA48 in our study cohort, rising to 23.5% (4/17) when considering only familial cases. All our SCA48 patients had cerebellar ataxia and dysarthria associated with cerebellar atrophy on brain magnetic resonance imaging; of note, many cases were also associated with parkinsonism, chorea and dystonia. CCAS also occurred frequently, whereas definite signs of pyramidal tract dysfunction and peripheral nervous system involvement were absent. One SCA48 patient presented with hypogonadism, associated with other autoimmune endocrine dysfunctions.

CONCLUSIONS

Our results support SCA48 as a significant cause of adult-onset SCA. Besides CCAS, our SCA48 patients often showed movement disorders and other clinical manifestations previously described in SCAR16, linked to biallelic variants in the same gene, thus suggesting a continuous clinical spectrum and significant overlap amongst recessive and dominantly inherited mutations in STUB1.

ERIGO: a possible strategy to treat orthostatic hypotension in progressive supranuclear palsy? A feasibility study

Progressive supranuclear palsy (PSP) is a neurodegenerative disease of the central nervous system, presenting with different clinical phenotypes, all involving the extrapyramidal system. Orthostatic hypotension (OH) is a common symptom of cardiovascular autonomic dysfunction. OH is defined as a fall in systolic blood pressure of at least 20 mmHg and/or a fall in diastolic blood pressure of at least 10 mmHg on standing or head-up tilt. In this pilot study, we tested the feasibility and efficacy of the ERIGO® device in managing OH non-responsive to conventional treatments in a sample of patients with PSP. OH was chosen as the primary outcome, as the symptom is a serious complication in neurodegenerative disorders, challenging the rehabilitation treatment. Six patients received intensive training using ERIGO®, a robot- assisted tilt table with an integrated leg movement system that allows progressive verticalization of the patient, and application of functional electrical stimulation. In all the participants, OH improved after the training with the device, suggesting that robotic verticalization may be a feasible and effective tool in improving blood pressure stability in patients with PSP. Further studies in larger samples, also including patients with other neurodegenerative disorders associated with OH, are needed to confirm these promising results.

Dietary patterns were not associated with age-related macular degeneration: a cross-sectional analysis in the Irish Nun Eye Study

BACKGROUND

Analysing dietary patterns (DP) evaluates overall dietary intake, taking account of its complexity, quality, variance and the interaction between different foods, providing an alternative approach for the evaluation of nutritional influences on age-related macular degeneration (AMD) risk.

AIMS

To evaluate the relationship between DP and AMD in an older female population.

METHODS

Data was analysed from the cross-sectional Irish Nun Eye Study involving 1233 older women with a restricted lifestyle (mean age 76.3 years [range, 56-100 years). The Wisconsin Age-related Maculopathy Grading System was used to classify digital colour macular fundus images and dietary intake was assessed using a food frequency questionnaire (n = 1033). A posteriori DP were derived using principal component analysis. Logistic regression models examined associations between DP and AMD risk with adjustment for confounders.

RESULTS

Two DP were identified: a 'healthy' pattern characterised by a high intake of oily fish, wholegrains, vegetables and fruit; and an 'unhealthy' pattern characterised by high-fat dairy products, sugar, sweets and chips. Of the participants included within the analysis, AMD status were categorised as controls (n = 818, 86.9%), early AMD (n = 83, 8.8%) and late AMD (n = 21, 2.2%). Regression analysis failed to identify any significant associations between healthy or unhealthy DP and AMD risk, in unadjusted and adjusted models.

CONCLUSION

No evidence of an association between the DP identified and AMD risk was detected in this well-characterised population. Further research is required to determine the overall dietary influences on AMD risk in general population cohorts.

Prevalence and phenotype of the c.1529C>T SPG7 variant in adult-onset cerebellar ataxia in Italy

BACKGROUND AND PURPOSE

Hereditary ataxias are heterogeneous groups of neurodegenerative disorders, characterized by cerebellar syndromes associated with dysarthria, oculomotor and corticospinal signs, neuropathy and cognitive impairment. Recent reports have suggested mutations in the SPG7 gene, causing the most common form of autosomal recessive spastic paraplegia (MIM#607259), as a main cause of ataxias. The majority of described patients were homozygotes or compound heterozygotes for the c.1529C>T (p.Ala510Val) change. We screened a cohort of 895 Italian patients with ataxia for p.Ala510Val in order to define the prevalence and genotype-phenotype correlation of this variant.

METHODS

We set up a rapid assay for c.1529C>T using restriction enzyme analysis after polymerase chain reaction amplification. We confirmed the diagnosis with Sanger sequencing.

RESULTS

We identified eight homozygotes and 13 compound heterozygotes, including two novel variants affecting splicing. Mutated patients showed a pure cerebellar ataxia at onset, evolving in mild spastic ataxia (alternatively) associated with dysarthria (~80% of patients), urinary urgency (~30%) and pyramidal signs (~70%). Comparing homozygotes and compound heterozygotes, we noted a difference in age at onset and Scale for the Assessment and Rating of Ataxia score between the two groups, supporting an earlier and more severe phenotype in compound heterozygotes versus homozygotes.

CONCLUSIONS

The SPG7 c.1529C>T (p.Ala510Val) mutants accounted for 2.3% of cerebellar ataxia cases in Italy, suggesting that this variant should be considered as a priority test in the presence of late-onset pure ataxia. Moreover, the heterozygous/homozygous genotype appeared to predict the onset of clinical manifestation and disease progression.

Estimated Glomerular Filtration Rate is not Associated with Alzheimer's Disease in a Northern Ireland Cohort

BACKGROUND

Alzheimer's disease (AD) prevalence is increasing globally and typically progresses for several years prior to clinical presentation of dementia. Renal dysfunction and vascular disease have been reported in association with dementia in several cross-sectional and longitudinal studies, and may contribute to AD risk. Experimental and observational studies suggest amyloid-β (Aβ) clearance may be impaired in chronic kidney disease (CKD) indicating a mechanism for increased AD risk.

OBJECTIVE

The objective of this study was to compare estimated glomerular filtration rate (eGFR) between individuals with AD and cognitively intact controls, controlling for potential confounding factors.

METHODS

A cross-sectional, case-control study was carried out in 317 cognitively normal participants and 253 cases with a clinical diagnosis of AD in a UK tertiary care dementia clinic. Associations were considered using logistic regression adjusting for confounding variables (age, APOEɛ4 genotype, systolic blood pressure, education (left school at 14), and smoking status).

RESULTS

AD cases were older than cognitively intact controls, had lower MMSE scores, were more likely to have at least one APOEɛ4 allele, had higher rates of smoking, were more likely to be taking aspirin and/or clopidogrel, and had lower blood pressure. We found no significant association between eGFR and AD both before and following adjustment for appropriate confounders.

CONCLUSION

This study failed to find an association between eGFR and AD in a cross-sectional sample study of elderly white individuals.

Dietary Patterns and Retinal Vessel Caliber in the Irish Nun Eye Study

BACKGROUND

Retinal vessel abnormalities are associated with cardiovascular disease risk. Widening of retinal venules is associated with increased risk of stroke while narrowing of retinal arterioles independently predicts incident hypertension, coronary heart disease and diabetes. Dietary factors are known to play an important role in cardiovascular health. However, few studies have examined the association between dietary patterns (DPs) and retinal microvascular health.

OBJECTIVE

To examine the association between 'a posteriori'-derived DPs and retinal vascular caliber (RVC) in older women with a restricted lifestyle.

METHODS

This was a cross-sectional study of 1233 participants (mean age: 76.3 years) from the Irish Nun Eye Study (INES). Computer-assisted software was used to measure RVC from digital eye images using standardized protocols. Dietary intake was assessed using a food frequency questionnaire (FFQ). DP analysis was performed using principal component analysis from completed FFQs. Regression models were used to assess associations between DPs and retinal vessel diameters, adjusting for age, body mass index, refraction, hypertension, diabetes mellitus, ischemic heart disease, cerebrovascular accident and fellow eye RVC.

RESULTS

Two DPs were identified: a 'healthy' pattern with high factor loadings for fruit, vegetables, wholegrains and oily fish and an 'unhealthy' pattern with high factor loadings for sugar and sweets, chips, high fat dairy products and French fries. Adjusted linear regression analysis revealed that those who adhered most closely to the unhealthy DP had wider central retinal venular equivalent (CRVE) (p=0.03) and narrower central retinal arteriolar equivalent (CRAE) (p=0.01) compared to the least unhealthy DP. No independent relationship was observed between the healthy DP and RVC.

CONCLUSION

In this cohort of older women with a restricted lifestyle, an unhealthy DP was independently associated with an unfavorable retinal profile, namely a widening of retinal venules and narrowing of retinal arterioles.

Speckle variance OCT for depth resolved assessment of the viability of bovine embryos

The morphology of embryos produced by in vitro fertilization (IVF) is commonly used to estimate their viability. However, imaging by standard microscopy is subjective and unable to assess the embryo on a cellular scale after compaction. Optical coherence tomography is an imaging technique that can produce a depth-resolved profile of a sample and can be coupled with speckle variance (SV) to detect motion on a micron scale. In this study, day 7 post-IVF bovine embryos were observed either short-term (10 minutes) or long-term (over 18 hours) and analyzed by swept source OCT and SV to resolve their depth profile and characterize micron-scale movements potentially associated with viability. The percentage of en face images showing movement at any given time was calculated as a method to detect the vital status of the embryo. This method could be used to measure the levels of damage sustained by an embryo, for example after cryopreservation, in a rapid and non-invasive way.

Peripheral blood mononuclear cells from neovascular age-related macular degeneration patients produce higher levels of chemokines CCL2 (MCP-1) and CXCL8 (IL-8)

Background

Infiltrating immune cells including monocytes/macrophages have been implicated in the pathogenesis of neovascular age-related macular degeneration (nAMD). The aim of this study was to investigate the cytokine and chemokine expression and secretion profile of peripheral blood mononuclear cells (PBMCs) from nAMD patients and the relationship between the cytokine/chemokine expression profile and clinical phenotype of nAMD, including macular fibrosis, macular atrophy or the responsiveness to anti-VEGF therapy.

Methods

One hundred sixty-one nAMD patients and 43 controls were enrolled in this study. nAMD patients were divided into subgroups based on the presence/absence of (1) macular atrophy, (2) macular fibrosis and (3) responsiveness to anti-VEGF therapy; 25–30 ml of peripheral blood were obtained from all participants and 5 ml were used for serum collection, and the remaining were used for PBMC isolation using density gradient centrifugation. Intracellular cytokine expressions by PBMCs following phorbol 12-myristate 13-acetate (PMA) and ionomycin stimulation were examined using flow cytometry. Cytokine productions in lipopolysaccharides (LPS)-or 1% oxygen -treated PBMC were measured using cytometric bead array (CBA) assay. In addition, cytokine and chemokine levels in the serum were also measured by CBA assay.

Results

PBMCs from nAMD patients secreted higher levels of IL-8, CCL2 and VEGF, especially following LPS and 1% oxygen stimulation, than those from controls. 60~80% of IL-8 producing cells were CD11b⁺CD3⁻ monocytes. The percentage of CD11b⁺CD3⁻ IL-8⁺ was significantly increased in nAMD patients compared to controls. PBMCs from nAMD patients without macular fibrosis produced the highest levels of IL-8 and CCL2, whilst PBMCs from nAMD patients with macular atrophy produced highest levels of VEGF. In addition, PBMCs from patients who partially responded to anti-VEGF produced higher levels of IL-8 compared to the cells from complete responders. Interestingly, serum level of CCL2 was not increased in nAMD patients although there was a trend of increased IL-8 in nAMD patients.

Conclusions

PBMCs, in particular monocytes, may contribute to CNV development in nAMD through secreting elevated levels of IL-8, CCL2 and VEGF after they are recruited to the macula. Apart from VEGF, IL-8 and CCL2 may be additional targets for nAMD management.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-017-0820-y) contains supplementary material, which is available to authorized users.

Myotonic dystrophy type 1: role of CCG, CTC and CGG interruptions within DMPK alleles in the pathogenesis and molecular diagnosis

Myotonic dystrophy type 1 (DM1) is a multisystem neuromuscular disease caused by a CTG triplet expansion in the 3'-untranslated region (3'-UTR) of DMPK gene. This CTG array is usually uninterrupted in both healthy and DM1 patients, but recent studies identified pathological variant expansions containing unstable CCG, CTC and CGG interruptions with a prevalence of 3-5% of cases. In this review, we will describe the clinical, molecular and genetic issues related to the occurrence of variant expansions associated with DM1. Indeed, the identification of these complex DMPK alleles leads to practical consequences in DM1 genetic counseling and testing, because these exams can give false negative results. Moreover, DM1 patients carrying interrupted alleles can manifest either additional atypical neurological symptoms or, conversely, mild, late-onset forms. Therefore, the prognosis of the disease in these patients is difficult to determine because of the great uncertainty about the genotype-phenotype correlations. We will discuss the putative effects of the variant DM1 alleles on the pathogenic disease mechanisms, including mitotic and meiotic repeats instability and splicing alteration typical of DM1 tissues. Interruptions within the DMPK expanded alleles could also interfere with the chromatin structure, the transcriptional activity of the DM1 locus and the interaction with RNA CUG-binding proteins.

STAT3 Activation in Circulating Monocytes Contributes to Neovascular Age-Related Macular Degeneration

Infiltrating macrophages are critically involved in pathogenic angiogenesis such as neovascular age-related macular degeneration (nAMD). Macrophages originate from circulating monocytes and three subtypes of monocyte exist in humans: classical (CD14⁺CD16^-), non-classical (CD14^-CD16⁺) and intermediate (CD14⁺CD16⁺) monocytes. The aim of this study was to investigate the role of circulating monocyte in neovascular age-related macular degeneration (nAMD). Flow cytometry analysis showed that the intermediate monocytes from nAMD patients expressed higher levels of CX3CR1 and HLA-DR compared to those from controls. Monocytes from nAMD patients expressed higher levels of phosphorylated Signal Transducer and Activator of Transcription 3 (pSTAT3), and produced higher amount of VEGF. In the mouse model of choroidal neovascularization (CNV), pSTAT3 expression was increased in the retina and RPE/choroid, and 49.24% of infiltrating macrophages express pSTAT3. Genetic deletion of the Suppressor of Cytokine Signalling 3 (SOCS3) in myeloid cells in the LysM-Cre^+/-:SOCS3^fl/fl mice resulted in spontaneous STAT3 activation and accelerated CNV formation. Inhibition of STAT3 activation using a small peptide LLL12 suppressed laser-induced CNV. Our results suggest that monocytes, in particular the intermediate subset of monocytes are activated in nAMD patients. STAT3 activation in circulating monocytes may contribute to the development of choroidal neovascularisation in AMD.

DJ-1 modulates mitochondrial response to oxidative stress: clues from a novel diagnosis of PARK7

DJ-1 mutations are associated to early-onset Parkinson's disease and accounts for about 1-2% of the genetic forms. The protein is involved in many biological processes and its role in mitochondrial regulation is gaining great interest, even if its function in mitochondria is still unclear. We describe a 47-year-old woman affected by a multisystem disorder characterized by progressive, early-onset parkinsonism plus distal spinal amyotrophy, cataracts and sensory-neural deafness associated with a novel homozygous c.461C>A [p.T154K] mutation in DJ-1. Patient's cultured fibroblasts showed low ATP synthesis, high ROS levels and reduced amount of some subunits of mitochondrial complex I; biomarkers of oxidative stress also resulted abnormal in patient's blood. The clinical pattern of multisystem involvement and the biochemical findings in our patient highlight the role for DJ-1 in modulating mitochondrial response against oxidative stress.

Hereditary spastic paraplegia: Novel mutations and expansion of the phenotype variability in SPG56

We describe a novel sporadic case of SPG56, a rare complicated form of HSP, that expands the clinical and molecular spectrum of the disease, being associated to novel mutations in CYP2U1 and showing as novel feature dorsal hydromyelia at spinal cord MRI. The patient presented an early-onset, slowly progressive paraparesis associated with mild mental retardation. Neurological assessments included the Spastic Paraplegia Rating Scale (SPRS), Mental Deterioration Battery (MDB), and Wechsler Adult Intelligence Scale (WAIS), neurophysiological and neuroimaging studies. Targeted next-generation sequencing panels for the whole set of genes associated with HSP were performed in the probands and her relatives. Neuroimaging studies showed dorsal hydromyelia but no brain MRI abnormalities. Targeted next-generation identified two novel mutations: the c.5C > A/p.S2* on the maternal allele in compound heterozygosity with the paternally-inherited c.1288+5G > C in CYP2U1. Both mutations predict early protein truncation and a loss of function. So far, only few SPG56 cases have been reported. This case, expands and further characterize the clinical and molecular spectrum of SPG56. In this regard, in consideration of the putative gene function in neurodevelopment, we suggest a causal association between CYP2U1 mutations and hydromyelia in our patient.

Mutational Analysis of the Rhodopsin Gene in Sector Retinitis Pigmentosa

BACKGROUND

To determine the role of rhodopsin (RHO) gene mutations in patients with sector retinitis pigmentosa (RP) from Northern Ireland.

DESIGN

A case series of sector RP in a tertiary ocular genetics clinic.

PARTICIPANTS

Four patients with sector RP were recruited from the Royal Victoria Hospital (Belfast, Northern Ireland) and Altnagelvin Hospital (Londonderry, Northern Ireland) following informed consent.

METHODS

The diagnosis of sector RP was based on clinical examination, International Society for Clinical Electrophysiology of Vision (ISCEV) standard electrophysiology, and visual field analysis. DNA was extracted from peripheral blood leucocytes and the coding regions and adjacent flanking intronic sequences of the RHO gene were polymerase chain reaction (PCR) amplified and cycle sequenced.

MAIN OUTCOME MEASURE

Rhodopsin mutational status.

RESULTS

A heterozygous missense mutation in RHO (c.173C > T) resulting in a non-conservative substitution of threonine to methionine (p. Thr58Met) was identified in one patient and was absent from 360 control individuals. This non-conservative substitution (p.Thr58Met) replaces a highly evolutionary conserved polar hydrophilic threonine residue with a non-polar hydrophobic methionine residue at position 58 near the cytoplasmic border of helix A of RHO.

CONCLUSIONS

The study identified a RHO gene mutation (p.Thr58Met) not previously reported in RP in a patient with sector RP. These findings outline the phenotypic variability associated with RHO mutations. It has been proposed that the regional effects of RHO mutations are likely to result from interplay between mutant alleles and other genetic, epigenetic and environmental factors.

Higher plasma levels of complement C3a, C4a and C5a increase the risk of subretinal fibrosis in neovascular age-related macular degeneration: Complement activation in AMD

Background

The aim of this study was to investigate the plasma levels of complement C3a, C4a, and C5a in different types of neovascular age-related macular degeneration (nAMD) and whether the levels were related to patients’ responsiveness to anti-VEGF therapy.

Results

Ninety-six nAMD patients (including 61 with choroidal neovascularisation (CNV), 17 with retinal angiomatous proliferation (RAP), 14 with polypoidal choroidal vasculopathy (PCV) and 4 unclassified patients) and 43 controls were recruited to this case–control study. Subretinal fibrosis was observed in 45 nAMD patients and was absent in 51 nAMD patients. In addition, the responsiveness to anti-VEGF (Lucentis) therapy was also evaluated in nAMD patients. Forty-four patients were complete responders, 48 were partially responders, and only 4 patients did not respond to the therapy. The plasma levels of C3a, C4a and C5a were significantly higher in nAMD patients compared to controls. Further analysis of nAMD subgroups showed that the levels of C3a, C4a and C5a were significantly increased in patients with CNV but not RAP and PCV. Significantly increased levels of C3a, C4a and C5a were also observed in nAMD patients with subretinal fibrosis but not in those without subretinal fibrosis. Higher levels of C3a were observed in nAMD patients who responded partially to anti-VEGF therapy.

Conclusions

Our results suggest increased systemic complement activation in nAMD patients with CNV but not RAP and PCV. Our results also suggest that higher levels of systemic complement activation may increase the risk of subretinal fibrosis in nAMD patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12979-016-0060-5) contains supplementary material, which is available to authorized users.

Lung cancer risk test trial: study design, participant baseline characteristics, bronchoscopy safety, and establishment of a biospecimen repository

BACKGROUND

The Lung Cancer Risk Test (LCRT) trial is a prospective cohort study comparing lung cancer incidence among persons with a positive or negative value for the LCRT, a 15 gene test measured in normal bronchial epithelial cells (NBEC). The purpose of this article is to describe the study design, primary endpoint, and safety; baseline characteristics of enrolled individuals; and establishment of a bio-specimen repository.

METHODS/DESIGN

Eligible participants were aged 50-90 years, current or former smokers with 20 pack-years or more cigarette smoking history, free of lung cancer, and willing to undergo bronchoscopic brush biopsy for NBEC sample collection. NBEC, peripheral blood samples, baseline CT, and medical and demographic data were collected from each subject.

DISCUSSION

Over a two-year span (2010-2012), 403 subjects were enrolled at 12 sites. At baseline 384 subjects remained in study and mean age and smoking history were 62.9 years and 50.4 pack-years respectively, with 34% current smokers. Obstructive lung disease (FEV1/FVC <0.7) was present in 157 (54%). No severe adverse events were associated with bronchoscopic brushing. An NBEC and matched peripheral blood bio-specimen repository was established. The demographic composition of the enrolled group is representative of the population for which the LCRT is intended. Specifically, based on baseline population characteristics we expect lung cancer incidence in this cohort to be representative of the population eligible for low-dose Computed Tomography (LDCT) lung cancer screening. Collection of NBEC by bronchial brush biopsy/bronchoscopy was safe and well-tolerated in this population. These findings support the feasibility of testing LCRT clinical utility in this prospective study. If validated, the LCRT has the potential to significantly narrow the population of individuals requiring annual low-dose helical CT screening for early detection of lung cancer and delay the onset of screening for individuals with results indicating low lung cancer risk. For these individuals, the small risk incurred by undergoing once in a lifetime bronchoscopic sample collection for LCRT may be offset by a reduction in their CT-related risks. The LCRT biospecimen repository will enable additional studies of genetic basis for COPD and/or lung cancer risk.

TRIAL REGISTRATION

The LCRT Study, NCT 01130285, was registered with Clinicaltrials.gov on May 24, 2010.

Plasma Complement factor H in Alzheimer's Disease

Biomarkers for Alzheimer's disease (AD) should meet several criteria, including simplicity of testing. Inappropriate activation of the complement cascade has been implicated in the pathogenesis of AD. Complement factor H (CFH) is a regulator of the cascade, but studies on plasma CFH levels in AD have provided mixed results. This study compared plasma CFH levels in 317 AD cases with 254 controls using an immunodiffusion assay. The sample had an 80% power to detect a difference of 23 mg/L between cases and controls, but no difference was evident. Plasma CFH may not be a suitable biomarker for AD.

Age-Related Macular Degeneration-Associated Genes in Alzheimer Disease

OBJECTIVES

Given the clinical and pathological similarities between age-related macular degeneration (AMD) and Alzheimer disease (AD), to assess whether AMD-associated single nucleotide polymorphisms (SNPs), including those from complement-related genes, are associated with AD.

DESIGN

A case-control association study-type design.

SETTING

A UK tertiary care dementia clinic.

PARTICIPANTS

322 cognitively normal participants and 258 cases with a clinical diagnosis of AD.

MEASUREMENTS

Polymorphisms in the following genes were studied: CFH, ARMS2, C2/CFB, C3, CFI/PLA2G12a, SERPING1, TLR3, TLR4, CRP, APOE, and TOMM40. Haplotypes were analysed for CFH, TOMM40, and APOE. Univariate analysis was performed for each genetic change and case-comparator status, and then correction for multiple testing performed.

RESULTS

The presence of an ε4 APOE allele was significantly associated with AD. No association was evident between CFH SNPs or haplotypes, or other AMD-associated SNPs tested, and AD. The exceptions were TOMM40 SNPs, which were associated with AD even after correction for multiple comparisons. The associations disappeared, however, when entered into a regression model including APOE genotypes.

CONCLUSIONS

The results for most SNPs tested, as well as CFH haplotypes, are novel. The functional effects of abnormal complement activity in AD's pathogenesis may be contradictory, but methodological reasons may underlie the lack of association-for example, genetic changes other than SNPs being involved.

Alterations in Circulating Immune Cells in Neovascular Age-Related Macular Degeneration

Neovascular age-related macular degeneration (nAMD) is the leading cause of irreversible blindness in developed countries. Recent advances have highlighted the essential role of inflammation in the development of the disease. In addition to local retinal chronic inflammatory response, systemic immune alterations have also been observed in AMD patients. In this study we investigated the association between the frequency of circulating leukocyte populations and the prevalence as well as clinical presentations of nAMD. Leukocyte subsets of 103 nAMD patients (most of them were receiving anti-VEGF therapy prior to enrolment) and 26 controls were analysed by flow cytometry by relative cell size, granularity and surface markers. Circulating CD11b(+) cells and CD16(hi)HLA-DR(-) neutrophils were significantly increased (P = 0.015 and 0.009 respectively) in nAMD when compared to controls. The percentage of circulating CD4(+) T-cells was reduced in nAMD patients without subretinal fibrosis (P = 0.026) compared to patients with subretinal fibrosis. There was no correlation between the percentage of circulating leukocytes and the responsiveness to anti-VEGF therapy in nAMD patients. Our results suggest that higher levels of circulating CD11b(+) cells and neutrophils are associated with nAMD and that reduced levels of CD4(+) T-cells are associated with the absence of subretinal fibrosis in nAMD.

Evaluation of the Retinal Vasculature in Hypertension and Chronic Kidney Disease in an Elderly Population of Irish Nuns

BACKGROUND

Chronic kidney disease (CKD) and hypertension are global public health problems associated with considerable morbidity, premature mortality and attendant healthcare costs. Previous studies have highlighted that non-invasive examination of the retinal microcirculation can detect microvascular pathology that is associated with systemic disorders of the circulatory system such as hypertension. We examined the associations between retinal vessel caliber (RVC) and fractal dimension (DF), with both hypertension and CKD in elderly Irish nuns.

METHODS

Data from 1233 participants in the cross-sectional observational Irish Nun Eye Study (INES) were assessed from digital photographs with a standardized protocol using computer-assisted software. Multivariate regression analyses were used to assess associations with hypertension and CKD, with adjustment for age, body mass index (BMI), refraction, fellow eye RVC, smoking, alcohol consumption, ischemic heart disease (IHD), cerebrovascular accident (CVA), diabetes and medication use.

RESULTS

In total, 1122 (91%) participants (mean age: 76.3 [range: 56-100] years) had gradable retinal images of sufficient quality for blood vessel assessment. Hypertension was significantly associated with a narrower central retinal arteriolar equivalent (CRAE) in a fully adjusted analysis (P = 0.002; effect size = -2.16 μm; 95% confidence intervals [CI]: -3.51, -0.81 μm). No significant associations between other retinal vascular parameters and hypertension or between any retinal vascular parameters and CKD were found.

CONCLUSIONS

Individuals with hypertension have significantly narrower retinal arterioles which may afford an earlier opportunity for tailored prevention and treatment options to optimize the structure and function of the microvasculature, providing additional clinical utility. No significant associations between retinal vascular parameters and CKD were detected.

The prevalence of age-related macular degeneration in Alzheimer's disease

BACKGROUND

Age-related macular degeneration (AMD) and Alzheimer's disease (AD) share several features, including the presence of extracellular abnormal deposits associated with neuronal degeneration, drusen, and plaques, respectively. Investigation of any association of AMD and specifically AD is worthwhile but has rarely been done.

OBJECTIVES

The aim of this study was to determine the prevalence of AMD in subjects with AD in comparison with an age-matched cognitively normal cohort.

METHODS

Cases were defined as those diagnosed with AD using standardized criteria as part of their clinical care, while controls were cognitively intact individuals aged 65 years or more. Dilated retinal photographs were taken, and a range of potentially confounding factors measured including APOE genotype. AMD features were recorded and AMD grades given.

RESULTS

Data was collected on 322 controls and 258 cases. While AMD was associated with AD, and the proportion of cases of advanced AMD in AD cases was twice that of controls, when corrected the association was lost. AD was associated with age, the presence of an APOE allele, and smoking, while being 'generally unwell recently' was associated with a reduced risk of AD.

CONCLUSION

AD and AMD are both associated with age, but our study does not find evidence they are associated with each other. However the retina offers an opportunity to non-invasively image neuronal tissue, and more sophisticated imaging techniques may shed light on ocular biomarkers of AD.

Unsupervised explorative data analysis of normal human leukocytes and BCR/ABL positive leukemic cells mid-infrared spectra

We proved the ability of Fourier Transform Infrared microspectroscopy (microFTIR) complemented by Principal Component Analysis (PCA) to detect protein phosphorylation/de-phosphorylation in mammalian cells. We analyzed by microFTIR human polymorphonuclear neutrophil (PMNs) leukocytes, mouse-derived parental Ba/F3 cells (Ba/F3#PAR), Ba/F3 cells transfected with p210(BCR/ABL) (Ba/F3#WT) and expressing high levels of protein tyrosine kinase (PTK), and human-derived BCR/ABL positive K562 leukemic cell sub-clones engineered to differently express receptor-type tyrosine-protein phosphatase gamma (PTPRG). Synchrotron radiation (SR) and conventional (globar) IR sources were used to perform microFTIR respectively, on single cells and over several cells within the same sample. Ex vivo time-course experiments were run, inducing maximal protein phosphorylation in PMNs by 100 nM N-formylated tripeptide fMLP. Within the specific IR fingerprint 1800-850 cm(-1) frequency domain, PCA identified two regions with maximal signal variance. These were used to model and test the robustness of PCA in representing the dynamics of protein phosphorylation/de-phosphorylation processes. An IR signal ratio marker reflecting the homeostatic control by protein kinases and phosphatases was identified in normal leukocytes. The models identified by microFTIR and PCA in normal leukocytes also distinguished BCR/ABL positive Ba/F3#WT from BCR/ABL negative Ba/F3#PAR cells as well as K562 cells exposed to functionally active protein tyrosine phosphatase recombinant protein ICD-Tat transduced in cells by HIV-1 Tat technology or cells treated with the PTK inhibitor imatinib mesylate (IMA) from cells exposed to phosphatase inactive (D1028A)ICD-Tat recombinant protein and untreated control cells, respectively. The IR signal marker correctly reflected the degrees of protein phosphorylation associated with abnormal PTK activity in BCR/ABL positive leukemic cells and in general was inversely related to the expression/activity of PTPRG in leukemic sub-clones. In conclusion, we have described a new, reliable and simple spectroscopic method to study the ex vivo protein phosphorylation/de-phosphorylation balance in cell models: it is suitable for biomedical and pharmacological research labs but it also needs further optimization and its evaluation on large cohorts of patients to be proposed in the clinical setting of leukemia.

Retinal microvascular network attenuation in Alzheimer's disease

INTRODUCTION

Cerebral small-vessel disease has been implicated in the development of Alzheimer's disease (AD). The retinal microvasculature enables the noninvasive visualization and evaluation of the systemic microcirculation. We evaluated retinal microvascular parameters in a case-control study of AD patients and cognitively normal controls.

METHODS

Retinal images were computationally analyzed and quantitative retinal parameters (caliber, fractal dimension, tortuosity, and bifurcation) measured. Regression models were used to compute odds ratios (OR) and confidence intervals (CI) for AD with adjustment for confounders.

RESULTS

Retinal images were available in 213 AD participants and 294 cognitively normal controls. Persons with lower venular fractal dimension (OR per standard deviation [SD] increase, 0.77 [CI: 0.62-0.97]) and lower arteriolar tortuosity (OR per SD increase, 0.78 [CI: 0.63-0.97]) were more likely to have AD after appropriate adjustment.

DISCUSSION

Patients with AD have a sparser retinal microvascular network and retinal microvascular variation may represent similar pathophysiological events within the cerebral microvasculature of patients with AD.