Diabetic Disease of the Eye in Canada: Consensus Statements from a Retina Specialist Working Group.

Despite advances in systemic care, diabetic disease of the eye (DDE) remains the leading cause of blindness worldwide. There is a critical gap of up-to-date, evidence-based guidance for ophthalmologists in Canada that includes evidence from recent randomized controlled trials. Previous guidance has not always given special consideration to applying treatments and managing DDE in the context of the healthcare system. This consensus statement aims to assist practitioners in the field by providing a spectrum of acceptable opinions on DDE treatment and management from recognized experts in the field. In compiling evidence and generating consensus, a working group of retinal specialists in Canada addressed clinical questions surrounding the four themes of disease, patient, management, and collaboration. The working group reviewed literature representing the highest level of evidence on DDE and shared their opinions on topics surrounding the epidemiology and pathophysiology of diabetic retinopathy and diabetic macular edema; diagnosis and monitoring; considerations around diabetes medication use; strategic considerations for management given systemic comorbidities, ocular comorbidities, and pregnancy; treatment goals and modalities for diabetic macular edema, non-proliferative and proliferative diabetic retinopathy, and retinal detachment; and interdisciplinary collaboration. Ultimately, this work highlighted that the retinal examination in DDE not only informs the treating ophthalmologist but can serve as a global index for disease progression across many tissues of the body. It highlighted further that DDE can be treated regardless of diabetic control, that a systemic approach to patient care will result in the best health outcomes, and prevention of visual complications requires a multidisciplinary management approach. Ophthalmologists must tailor their clinical approach to the needs and circumstances of individual patients and work within the realities of their healthcare setting.

Improving the understanding of how patients with non-dystrophic myotonia are selected for myotonia treatment with mexiletine (NaMuscla): outcomes of treatment impact using a European Delphi panel.

BACKGROUND: Non-dystrophic myotonias (NDMs) comprise muscle chloride and sodium channelopathies due to genetic defects of the CLCN1- and SCN4A-channels. No licensed antimyotonic treatment has been available until approval of mexiletine (NaMuscla®) for adult patients by the EMA in December 2018. This Delphi panel aimed to understand how outcomes of the pivotal phase III Mexiletine study (MYOMEX) translate to real world practice and investigate health resource use, quality of life and the natural history of NDM to support economic modelling and facilitate patient access. METHODS: Nine clinical experts in treating NDM took part in a two-round Delphi panel. Their knowledge of NDM and previous use of mexiletine as an off-label treatment prior to NaMuscla's approval ensured they could provide both qualitative context and quantitative estimates to support economic modelling comparing mexiletine (NaMuscla) to best supportive care. Consensus in four key areas was sought: healthcare resource utilization (HRU), treatment with mexiletine (NaMuscla), patient quality of life (QoL), and the natural history of disease. Concept questions were also asked, considering perceptions on the feasibility of mapping the validated Individualized Neuromuscular Quality of Life (INQoL) instrument to the generic EQ-5D™, and the potential impact on caregiver QoL. RESULTS: Consensus was achieved for key questions including the average long-term dosage of mexiletine (NaMuscla) in practice, the criteria for eligibility of myotonia treatment, the clinical importance of QoL outcomes in MYOMEX, the higher proportion of patients with increased QoL, and the reduction in the need for mental health resources for patients receiving mexiletine (NaMuscla). While consensus was not achieved for other questions, the results demonstrated that most experts felt mexiletine (NaMuscla) reduced the need for HRU and was expected to improve QoL. The QoL mapping exercise suggested that it is feasible to map domains of INQoL to EQ-5D. Points of interest for future research were identified, including that mexiletine (NaMuscla) may slow the annual decrease in QoL of patients over their lifetime, and a significant negative impact on QoL for some caregivers. CONCLUSIONS: This project successfully provided data from an informed group of clinical experts, complementing the currently available clinical trial data for mexiletine (NaMuscla) to support patient access decisions.

Disorganization of Retinal Inner Layers and Ellipsoid Zone Disruption Predict Visual Outcomes in Central Retinal Vein Occlusion.

PURPOSE: To assess the associations and predictive value of spectral-domain (SD) OCT inner and outer retinal structural parameters and visual acuity (VA) outcomes in macular edema (ME) secondary to central retinal vein occlusion (CRVO). DESIGN: Retrospective, longitudinal cohort study. PARTICIPANTS: Eighty-four patients with ME secondary to CRVO receiving pro re nata anti-vascular endothelial growth factor (VEGF) therapy at 3 tertiary-level retina referral centers. METHODS: In all participants, VA, demographic and clinical parameters, and SD OCT images from baseline, 3 months, and 12 months were reviewed. Spectral-domain OCT-based morphologic features in the 1500-µm foveal zone were analyzed by masked graders for disorganization of the retinal inner layers (DRIL), ellipsoid zone (EZ) and external limiting membrane disruption, cone outer segment tip (COST) visibility, cysts, subretinal and intraretinal fluid, and epiretinal membranes. MAIN OUTCOME MEASURES: Spectral-domain OCT-based retinal structural parameters and VA outcomes. RESULTS: In multivariate analyses adjusting for baseline VA, worsening VA over 1 year was associated with 1-year increases in DRIL (point estimate, 0.06 per 100 µm; P < 0.001) and EZ disruption (0.07 per 100 µm; P = 0.023), but decreased COST visibility (-0.09 per 100 µm; P = 0.018). A 3-month increase in DRIL (0.05 per 100 µm; P = 0.003) and EZ disruption (0.10 per 100 µm; P < 0.001) were the only factors predicting VA worsening over 1 year, after controlling for baseline VA. A multivariate model including 3-month evolution in DRIL, EZ disruption, and VA accounted for 86.3% of variability in 1-year VA change. Absolute differences between predicted and actual 1-year VA were within 2 lines in 80.9%. When DRIL increased by 250 µm or more over 3 months, no eyes showed VA improvement of 1 line or more in 1 year. When EZ disruption decreased by 250 µm or more over 3 months, no eyes worsened by 1 line or more over 1 year. CONCLUSIONS: Early recovery over 3 months in both DRIL and EZ parameters are key drivers of 1-year VA outcomes. Predictive models incorporating 3-month changes in DRIL and EZ disruption support their usefulness as potential robust determinants of future VA.

Association of Genetic Variants With Response to Anti-Vascular Endothelial Growth Factor Therapy in Age-Related Macular Degeneration.

Importance: Visual acuity (VA) outcomes differ considerably among patients with neovascular age-related macular degeneration (nAMD) treated with anti-vascular endothelial growth factor (VEGF) drugs. Identification of pharmacogenetic associations may help clinicians understand the mechanisms underlying this variability as well as pave the way for personalized treatment in nAMD. Objective: To identify genetic factors associated with variability in the response to anti-VEGF therapy for patients with nAMD. Design, Setting, and Participants: In this multicenter genome-wide association study, 678 patients with nAMD with genome-wide genotyping data were included in the discovery phase; 1380 additional patients with nAMD were genotyped for selected common variants in the replication phase. All participants received 3 monthly injections of bevacizumab or ranibizumab. Clinical data were evaluated for inclusion/exclusion criteria from October 2014 to October 2015, followed by data analysis from October 2015 to February 2016. For replication cohort genotyping, clinical data collection and analysis (including meta-analysis) was performed from March 2016 to April 2017. Main Outcomes and Measures: Change in VA after the loading dose of 3 monthly anti-VEGF injections compared with baseline. Results: Of the 2058 included patients, 1210 (58.8%) were women, and the mean (SD) age across all cohorts was 78 (7.4) years. Patients included in the discovery cohort and most of the patients in the replication cohorts were of European descent. The mean (SD) baseline VA was 51.3 (20.3) Early Treatment Diabetic Retinopathy Study (ETDRS) score letters, and the mean (SD) change in VA after the loading dose of 3 monthly injections was a gain of 5.1 (13.9) ETDRS score letters (ie, 1-line gain). Genome-wide single-variant analyses of common variants revealed 5 independent loci that reached a P value less than 10 × 10-5. After replication and meta-analysis of the lead variants, rs12138564 located in the CCT3 gene remained nominally associated with a better treatment outcome (ETDRS letter gain, 1.7; ß, 0.034; SE, 0.008; P = 1.38 × 10-5). Genome-wide gene-based optimal unified sequence kernel association test of rare variants showed genome-wide significant associations for the C10orf88 (P = 4.22 × 10-7) and UNC93B1 (P = 6.09 × 10-7) genes, in both cases leading to a worse treatment outcome. Patients carrying rare variants in the C10orf88 and UNC93B1 genes lost a mean (SD) VA of 30.6 (17.4) ETDRS score letters (ie, loss of 6.09 lines) and 26.5 (13.8) ETDRS score letters (ie, loss of 5.29 lines), respectively, after 3 months of anti-VEGF treatment. Conclusions and Relevance: We propose that there is a limited contribution of common genetic variants to variability in nAMD treatment response. Our results suggest that rare protein-altering variants in the C10orf88 and UNC93B1 genes are associated with a worse response to anti-VEGF therapy in patients with nAMD, but these results require further validation in other cohorts.

Case Report: Hydroxychloroquine Retinopathy.

SIGNIFICANCE: Hydroxychloroquine retinopathy causes irreversible central visual loss and can progress despite medication discontinuation. Appropriate dosing and recognition of early disease are important to minimize adverse visual sequelae. In 2016, the American Academy of Ophthalmology updated its 2011 recommendations for dosing, screening, and monitoring of hydroxychloroquine retinopathy. PURPOSE: The aim of this study was to report a case of hydroxychloroquine retinopathy in a patient who developed toxicity on a dose meeting safety thresholds from the 2011 guidelines (i.e., 6.5 mg/kg ideal body weight and cumulative dose <1000 g), but exceeding that from the 2016 revised recommendations (i.e., 5.0 mg/kg real body weight). CASE REPORT: A 61-year-old woman with rheumatoid arthritis treated with 400 mg/kg hydroxychloroquine daily for 6 years (daily dose, 5.72 mg/real body weight or 6.5 mg/kg ideal body weight; cumulative dose, 876 g) experienced progressive central vision loss and a scotoma affecting her reading ability and was referred to the Retina service. Prior yearly examination with only Ishihara color vision and Amsler grid testing was normal. On examination, visual acuity was 20/40 in the right eye and 20/30 in the left eye. A fundus examination showed bilateral bull's-eye maculopathy, a classic finding of hydroxychloroquine retinal toxicity. Fundus autofluorescence showed a parafoveal ring of speckled hypoautofluorescence and an external ring of increased signal. There were characteristic structural changes on spectral domain-optical coherence tomography, including parafoveal loss of the ellipsoid zone and outer nuclear layer. Humphrey visual field testing of the central 10-2 revealed incomplete paracentral annular scotoma. Subsequently, hydroxychloroquine was switched to sulfasalazine. CONCLUSIONS: The 2016 American Academy of Ophthalmology guidelines for hydroxychloroquine retinopathy were revised to reflect new dosing and care guidelines for early detection of retinal toxicity and to minimize the extent of irreversible vision loss.

MACULAR TELANGIECTASIA TYPE 2 IN AN OTHERWISE HEALTHY TEENAGE BOY WITH CONSANGUINEOUS PARENTS.

PURPOSE: To report a case of macular telangiectasia Type 2 in a teenage boy with consanguineous parents. METHOD: Clinical case report and literature review. RESULTS: A healthy 14-year-old boy presented with mildly reduced vision in both eyes. Visual acuity was 20/30 in the right eye and 20/25 in the left eye. Fundus examination revealed intraretinal crystals in both eyes and an intraretinal pigment plaque temporal to the fovea in the left eye. Neither eye showed evidence of choroidal neovascular membrane or peripheral telangiectasia. Fluorescein angiography revealed temporal juxtafoveal leakage in both eyes. Spectral-domain optical coherence tomography showed ellipsoid layer and external limiting membrane disruption in the right eye and an inner retinal pigment plaque with shadowing in the left eye. The patient was of South Asian descent, and his parents were first cousins. His younger brother and parents were unaffected with a normal fundus examination. CONCLUSION: This is the youngest reported case of a healthy individual with MacTel Type 2, which usually manifests in the fifth or sixth decade. This is also the only reported case of MacTel Type 2 with consanguineous parents. This proband offers a unique opportunity to study possible monogenic etiologies of the condition.

GWAS study using DNA pooling strategy identifies association of variant rs4910623 in OR52B4 gene with anti-VEGF treatment response in age-related macular degeneration.

Pooled DNA based GWAS to determine genetic association of SNPs with visual acuity (VA) outcome in anti-vascular endothelial growth factor (anti-VEGF) treated neovascular age-related macular degeneration (nAMD) patients. We performed pooled DNA based GWAS on 285 anti-VEGF treated nAMD patients using high density Illumina 4.3 M array. Primary outcome was change in VA in Early Treatment Diabetic Retinopathy Study (ETDRS) letters after 6 months of anti-VEGF treatment (patients who lost ≥5 ETDRS letters classified as non-responders and all remaining classified as responders). GWAS analysis identified 44 SNPs of interest: 37 with strong evidence of association (p < 9 × 10-8), 2 in drug resistance genes (p < 5 × 10-6) and 5 nonsynonymous changes (p < 1 × 10-4). In the validation phase, individual genotyping of 44 variants showed three SNPs (rs4910623 p = 5.6 × 10-5, rs323085 p = 6.5 × 10-4 and rs10198937 p = 1.30 × 10-3) remained associated with VA response at 6 months. SNP rs4910623 also associated with treatment response at 3 months (p = 1.5 × 10-3). Replication of these three SNPs in 376 patients revealed association of rs4910623 with poor VA response after 3 and 6 months of treatment (p = 2.4 × 10-3 and p = 3.5 × 10-2, respectively). Meta-analysis of both cohorts (673 samples) confirmed association of rs4910623 with poor VA response after 3 months (p = 1.2 × 10-5) and 6 months (p = 9.3 × 10-6) of treatment in nAMD patients.

Real-World Outcomes of Ranibizumab Treatment for Diabetic Macular Edema in a United Kingdom National Health Service Setting.

PURPOSE: To determine visual acuity (VA) and spectral-domain optical coherence tomography (OCT) outcomes with intravitreal ranibizumab for diabetic macular edema (DME) in a United Kingdom National Health Service clinical setting. DESIGN: Retrospective interventional case series. PARTICIPANTS: Consecutive patients with DME, treated with the first ranibizumab injection between August 2013 and March 2014 across 4 sites of Moorfields Eye Hospital, London. METHODS: Two hundred eyes of 164 consecutive patients with center-involving DME and VA ≤79 ETDRS letters, central subfield macular thickness (CST) ≥350 µm on Topcon 3D OCT 2000, initiated on a loading phase of 3 intravitreal ranibizumab injections and who had at least 6 months follow-up were reviewed. Subsequent retreatment was guided by VA and OCT with the aim of treating to stability. VA, OCT CST, and macular volume (MV) were recorded at baseline and monthly to 12 months. RESULTS: The mean VA, mean CST, and mean MV at baseline were 54.4 (± 15.26) letters, 490.16 (± 116.54) µm, and 10.46 (± 2.28) mm3. The mean VA change at 12 months was +6.6 (± 13.35) letters (P = .0003). A total of 40.3% of patients (n = 77) gained ≥10 letters and 25.1% (n = 48) gained ≥15 letters; 8.9% (n = 17) lost ≥10 letters and 6.3% (n = 12) lost ≥15 letters. At 12 months, the mean change in CST and MV were -133.9 (± 160.12) µm (P = .0001) and -1.5 (± 1.96) mm3 (P = .0001), respectively. An average of 7.2 (± 2.3) injections were given over 12 months. CONCLUSIONS: Outcomes with 3 loading injections of 0.5 mg ranibizumab given monthly followed by pro re nata retreatment in a clinical setting are comparable with outcomes from clinical trials.

A genetic variant in NRP1 is associated with worse response to ranibizumab treatment in neovascular age-related macular degeneration.

OBJECTIVE: The aim of the study was to investigate the role of single-nucleotide polymorphisms (SNPs) located in the neuropilin-1 (NRP1) gene in treatment response to antivascular endothelial growth factor (VEGF) therapy for neovascular age-related macular degeneration (nvAMD). METHODS: Four SNPs in the NRP1 gene (rs2229935, rs2247383, rs2070296, and rs2804495) were genotyped in a study cohort of 377 nvAMD patients who received the loading dose of three monthly ranibizumab injections. Treatment response was assessed as the change in visual acuity after three monthly loading injections compared with baseline. RESULTS: SNP rs2070296 was associated with change in visual acuity after 3 months of treatment. Patients carrying the GA or AA genotypes performed significantly worse than individuals carrying the GG genotype (P=0.01). A cumulative effect of rs2070296 in the NRP1 gene and rs4576072 located in the VEGF receptor 2 (VEGFR2 or KDR) gene, previously associated with treatment response, was observed. Patients carrying two risk alleles performed significantly worse than patients carrying zero or one risk allele (P=0.03), and patients with more than two risk alleles responded even worse to the therapy (P=3×10). The combined effect of these two SNPs on the response was also seen after 6 and 12 months of treatment. CONCLUSION: This study suggests that genetic variation in NRP1, a key molecule in VEGFA-driven neovascularization, influences treatment response to ranibizumab in nvAMD patients. The results of this study may be used to generate prediction models for treatment response, which in the future may help tailor medical care to individual needs.

Novel insights into the molecular pathogenesis of CYP4V2-associated Bietti's retinal dystrophy.

Bietti's crystalline dystrophy (BCD) is a rare, autosomal recessive retinal degenerative disease associated with mutations in CYP4V2. In this study, we describe the genetic and clinical findings in 19 unrelated BCD patients recruited from five international retinal dystrophy clinics. Patients underwent ophthalmic examinations and were screened for CYP4V2 mutations by Sanger sequencing and quantitative polymerase chain reaction (qPCR) copy number variation screening. Eight CYP4V2 mutations were found in 10/19 patients, including three patients in whom only monoallelic mutations were detected. Four novel mutations were identified: c.604G>A; p.(Glu202Lys), c.242C>G; p.(Thr81Arg), c.604+4A>G; p.(?), and c.1249dup; p.(Thr417Asnfs*2). In addition, we identified a heterozygous paternally inherited genomic deletion of at least 3.8 Mb, encompassing the complete CYP4V2 gene and several other genes, which is novel. Clinically, patients demonstrated phenotypic variability, predominantly showing choroidal sclerosis, attenuated vessels, and crystalline deposits of varying degrees of severity. To our knowledge, our study reports the first heterozygous CYP4V2 deletion and hence a novel mutational mechanism underlying BCD. Our results emphasize the importance of copy number screening in BCD. Finally, the identification of CYP4V2-negative patients with indistinguishable phenotypes from CYP4V2-positive patients might suggest the presence of mutations outside the coding regions of CYP4V2, or locus heterogeneity, which is unreported so far.

Profile and geographical distribution of reported cutaneous leishmaniasis cases in Northwestern Saudi Arabia, from 2010 to 2013

Objective: To describe the profile and geographical distribution of reported cases of cutaneous leishmaniasis (CL) in the province of Hail, Saudi Arabia from 2010 to 2013. Methods: Human data were collected from the dermatology service of both King Khaled and General Hail hospitals. Results: A total of 483 confirmed CL cases were investigated. Cutaneous leishmaniasis follows a seasonal distribution related to the activity of the phlebotomine sand fly fauna. Both saudi and non saudi patients were almost equally infected. The number of reported cases of CL in men was higher than that in females. The frequency of CL was asoociated with age and increased in teenager and adult group. By analyzing the geographical distribution, the majority of Hail districts were affected with this disease. However it is more prevalent in Hail city. Conclusions: The lack of data concerning the parasite, the sand fly fauna and the existing transmission cycles in Hail province make difficult to interpret the reported results and to follow up the spatio-temporal evolution of the disease.

Profile and geographical distribution of reported cutaneous leishmaniasis cases in Northwestern Saudi Arabia, from 2010 to 2013

OBJECTIVE@#To describe the profile and geographical distribution of reported cases of cutaneous leishmaniasis (CL) in the province of Hail, Saudi Arabia from 2010 to 2013.@*METHODS@#Human data were collected from the dermatology service of both King Khaled and General Hail hospitals.@*RESULTS@#A total of 483 confirmed CL cases were investigated. Cutaneous leishmaniasis follows a seasonal distribution related to the activity of the phlebotomine sand fly fauna. Both saudi and non saudi patients were almost equally infected. The number of reported cases of CL in men was higher than that in females. The frequency of CL was asoociated with age and increased in teenager and adult group. By analyzing the geographical distribution, the majority of Hail districts were affected with this disease. However it is more prevalent in Hail city.@*CONCLUSIONS@#The lack of data concerning the parasite, the sand fly fauna and the existing transmission cycles in Hail province make difficult to interpret the reported results and to follow up the spatio-temporal evolution of the disease.

Profile and geographical distribution of reported cutaneous leishmaniasis cases in Northwestern Saudi Arabia, from 2010 to 2013

Objective: To describe the profile and geographical distribution of reported cases of cutaneous leishmaniasis (CL) in the province of Hail, Saudi Arabia from 2010 to 2013. Methods:Human data were collected from the dermatology service of both King Khaled and General Hail hospitals. Results: A total of 483 confirmed CL cases were investigated. Cutaneous leishmaniasis follows a seasonal distribution related to the activity of the phlebotomine sand fly fauna. Both saudi and non saudi patients were almost equally infected. The number of reported cases of CL in men was higher than that in females. The frequency of CL was asoociated with age and increased in teenager and adult group. By analyzing the geographical distribution, the majority of Hail districts were affected with this disease. However it is more prevalent in Hail city. Conclusions: The lack of data concerning the parasite, the sand fly fauna and the existing transmission cycles in Hail province make difficult to interpret the reported results and to follow up the spatio-temporal evolution of the disease.

Cumulative effect of risk alleles in CFH, ARMS2, and VEGFA on the response to ranibizumab treatment in age-related macular degeneration.

PURPOSE: Intravitreal ranibizumab injections currently are the standard treatment for neovascular age-related macular degeneration (AMD). However, a broad range of response rates have been observed, the reasons for which are poorly understood. This pharmacogenetic study evaluated the impact of high-risk alleles in CFH, ARMS2, VEGFA, vascular endothelial growth factor (VEGF) receptor KDR, and genes involved in angiogenesis (LRP5, FZD4) on the response to ranibizumab treatment and on the age of treatment onset. In contrast to previous studies, the data were stratified according to the number of high-risk alleles to enable the study of the combined effects of these genotypes on the treatment response. DESIGN: Case series study. PARTICIPANTS: A cohort of 420 eyes of 397 neovascular AMD patients. METHODS: The change in visual acuity (VA) between baseline and after 3 ranibizumab injections was calculated. Genotyping of single nucleotide polymorphisms in the CFH, ARMS2, VEGFA, KDR, LPR5, and FZD4 genes was performed. Associations were assessed using linear mixed models. MAIN OUTCOME MEASURES: The VA change after 3 ranibizumab injections and the age of neovascular disease onset. RESULTS: After ranibizumab treatment, AMD patients without risk alleles in the CFH and ARMS2 genes (4.8%) demonstrated a mean VA improvement of 10 Early Treatment Diabetic Retinopathy Study (ETDRS) letters, whereas no VA improvement was observed in AMD patients with 4 CFH and ARMS2 risk alleles (6.9%; P = 0.014). Patients with 4 high-risk alleles in CFH and ARMS2 were 5.2 years younger than patients with 1 or 2 risk alleles, respectively (63.5%; P<0.0001). The mean age at which the first ranibizumab treatment was carried out among AMD patients with all 6 risk alleles in CFH, ARMS2, and VEGFA was 65.9 years (2%) versus 75.3 years in patients with 0 or 1 high-risk allele (8.8%; P = 0.001). After ranibizumab treatment, patients with 6 high-risk alleles demonstrated a mean VA loss of 10 ETDRS letters (P<0.0001). CONCLUSIONS: This study evaluated the largest pharmacogenetic AMD cohort reported to date. A cumulative effect of high-risk alleles in CFH, ARMS2, and VEGFA seems to be associated with a younger age of onset in combination with poor response rates to ranibizumab treatment.

Homozygosity mapping in patients with cone-rod dystrophy: novel mutations and clinical characterizations.

PURPOSE: To determine the genetic defect and to describe the clinical characteristics in a cohort of mainly nonconsanguineous cone-rod dystrophy (CRD) patients. METHODS: One hundred thirty-nine patients with diagnosed CRD were recruited. Ninety of them were screened for known mutations in ABCA4, and those carrying one or two mutations were excluded from further research. Genome-wide homozygosity mapping was performed in the remaining 108. Known genes associated with autosomal recessive retinal dystrophies located within a homozygous region were screened for mutations. Patients in whom a mutation was detected underwent further ophthalmic examination. RESULTS: Homozygous sequence variants were identified in eight CRD families, six of which were nonconsanguineous. The variants were detected in the following six genes: ABCA4, CABP4, CERKL, EYS, KCNV2, and PROM1. Patients carrying mutations in ABCA4, CERKL, and PROM1 had typical CRD symptoms, but a variety of retinal appearances on funduscopy, optical coherence tomography, and autofluorescence imaging. CONCLUSIONS: Homozygosity mapping led to the identification of new mutations in consanguineous and nonconsanguineous patients with retinal dystrophy. Detailed clinical characterization revealed a variety of retinal appearances, ranging from nearly normal to extensive retinal remodeling, retinal thinning, and debris accumulation. Although CRD was initially diagnosed in all patients, the molecular findings led to a reappraisal of the diagnosis in patients carrying mutations in EYS, CABP4, and KCNV2.

Regulation of collagen synthesis by inhibitory Smad7 in cardiac myofibroblasts.

Transforming growth factor-beta(1) (TGF-beta(1)) signal and downstream Smads play an important role in tissue fibrosis and matrix remodeling in various etiologies of heart failure. Inhibitory Smad7 (I-Smad7) is an inducible regulatory Smad protein that antagonizes TGF-beta(1) signal mediated via direct abrogation of R-Smad phosphorylation. The effect of ectopic I-Smad7 on net collagen production was investigated using hydroxyproline assay. Adenovirus-mediated I-Smad7 gene (at 100 multiplicity of infection) transfer was associated with significant decrease of collagen synthesis in the presence and absence of TGF-beta(1) in primary rat cardiac myofibroblasts. In I-Smad7-infected cells, we also observed the ablation of TGF-beta(1)-induced R-Smad2 phosphorylation vs. LacZ controls. Overdriven I-Smad7 was associated with significantly increased expression of immunoreactive 65-kDa matrix metalloproteinase-2 (MMP-2) protein in culture medium of myofibroblast compared with LacZ-infected cells. Expression of the 72-kDa MMP-2 variant, e.g., the inactive form, was not altered by exogenous I-Smad7 transfection/overexpression. Furthermore, I-Smad7 overexpression was associated with a significant increase and decrease in expression of p27 and phospho-Rb protein, respectively, as well as reduced [(3)H]thymidine incorporation vs. Ad-LacZ-infected controls. We suggest that negative modulation of R-Smad phosphorylation by ectopic I-Smad7 may contribute to the downregulation of collagen in cardiac myofibroblasts and may suppress the proliferation of these cells. Thus treatments targeting the collagen deposition by overexpression of I-Smad7 may provide a new therapeutic strategy for cardiac fibrosis.

GABA(B) receptor activation and limbic network ictogenesis.

Rat brain slices containing interconnected hippocampus and entorhinal cortex (EC) responded to 4-aminopyridine (50 microM) application by generating: (i) CA3-driven interictal discharges that propagated to the EC; and (ii) N-methyl-D-aspartic (NMDA) acid receptor-dependent ictal events originating in EC (cf. J. Neurosci. 17 (1997) 9308 for experiments made in brain slices). Ictal discharges disappeared within 1-2 h, but were re-established by cutting the Schaffer collaterals, which abolished CA3-driven interictal discharge propagation to EC. In intact slices, GABA(B) receptor activation by baclofen (5-40 microM): (i) depressed CA3-driven interictal activity; and (ii) disclosed non-NMDA glutamatergic receptor-dependent ictal discharges originating in CA3 and propagating to EC. These effects were reversed by the GABA(B) receptor antagonist CGP 35348 (0.5 mM). Application of increasing baclofen doses to slices in which hippocampus and EC networks were surgically isolated decreased epileptiform events with an IC50 that was lower in EC (0.6 microM; n = 12) than in CA3 (2.5 microM; n = 12). Hence, under control conditions, EC ictogenesis depends on NMDA receptor function and is controlled by CA3-driven output activity; in contrast, following GABA(B) receptor activation EC excitability is depressed to a greater extent than CA3, which leads to non-NMDA glutamatergic receptor-mediated ictogenesis in CA3. We propose that GABA(B) receptor modulation may represent an important mechanism for setting the site of initiation, the modalities of propagation and the glutamatergic receptor properties of ictogenesis in the limbic system and, perhaps, in mesial temporal lobe epilepsy patients.