METHYLATION-ASSOCIATED PATHWAYS IN MACULAR TELANGIECTASIA TYPE 2 AND OPHTHALMOLOGIC FINDINGS IN PATIENTS WITH GENETIC METHYLATION DISORDERS.

PURPOSE: Serine (Ser) and glycine (Gly) levels were reported to differ between patients with macular telangiectasia type 2 (MacTel) compared with healthy controls. Because they are closely related to methylation metabolism, this report investigates methylation-associated metabolite levels in patients with MacTel and retinal changes in monogenetic methylation disorders. METHODS: Prospective, monocentric study on patients with MacTel and healthy controls underwent a standardized protocol including a blood draw. Methylation-associated metabolite levels in plasma were determined using targeted quantitative metabolomics. Furthermore, patient records of cystathionine beta-synthase, methylenetetrahydrofolate reductase, and methylmalonic aciduria and homocystinuria type C protein (MMACHC) deficiency were screened for reported retinal changes. RESULTS: In total, 29 patients with MacTel and 27 healthy controls were included. Patients with MacTel showed lower plasma Ser ( P = 0.02 and P = 0.01) and Gly ( P = 0.11 and P = 0.11) levels than controls. Principal component analyses revealed that methylation-associated metabolite, especially homocysteine, contributed to a distinct clustering of patients with MacTel. No retinal changes were seen in cystathionine beta-synthase (n = 1) and methylenetetrahydrofolate reductase (n = 2) deficiency, while two patients with MMACHC (n = 4) deficiency displayed extensive macular dystrophy. CONCLUSION: Patients with MacTel show distinct clustering of methylation-associated metabolite compared with controls. Of the three homocystinurias, only MMACHC resulted in macular dystrophy, possibly due to distinct compensatory pathways.

Efficacy and Safety of Anti-Vascular Endothelial Growth Factor Drugs for Coats' Disease Treatment: A Systematic Review.

Purpose: The efficacy and safety of anti-vascular endothelial growth factor (anti-VEGF) treatment for Coats' disease remains controversial. This study was designed to evaluate the efficacy and safety of anti-VEGF treatment for Coats' disease. Methods: PubMed, Embase, The Cochrane Library, Clinical Trials, CNKI, and WanFang databases were systematically searched for clinical efficacy and safety studies on anti-VEGF treatment for Coats' disease through June 2021. Study selection, data extraction, and quality assessment were independently performed by 2 reviewers. Quality assessments were performed using the Joanna Briggs Institute Critical Appraisal tools and GRADE-CERQual. Results: A total of 1,501 articles were retrieved and reviewed, of which 24 case series involving 378 patients (range: 3-67 patients each with 3-71 eyes) were included in the analysis. No randomized controlled trials, case-controlled studies, or cohort studies were available for analysis. Most patients were male (60.0%-92.9%), aged 1.35-42.3 years, with a median follow-up time ranging from 3 to 63 months. Among the 24 case series, 22 reported changes in the visual acuity (VA) after anti-VEGF treatment and 21 reported safety outcomes. The results showed that VA improved in 73 patients (37.63%), was stable in 89 (45.87%), and worsening VA was observed in 12 cases (6.19%). The most common adverse event was fibrotic changes (n = 35). Systemic complications were not observed. Conclusions: The results of this study indicate that anti-VEGF drugs provide an effective and relatively safe treatment strategy for Coats' disease. However, conducting well-designed, prospective, randomized clinical trials are necessary to confirm our findings.

iPSC-derived retinal pigmented epithelial cells from patients with macular telangiectasia show decreased mitochondrial function.

Patient-derived induced pluripotent stem cells (iPSCs) provide a powerful tool for identifying cellular and molecular mechanisms of disease. Macular telangiectasia type 2 (MacTel) is a rare, late-onset degenerative retinal disease with an extremely heterogeneous genetic architecture, lending itself to the use of iPSCs. Whole-exome sequencing screens and pedigree analyses have identified rare causative mutations that account for less than 5% of cases. Metabolomic surveys of patient populations and GWAS have linked MacTel to decreased circulating levels of serine and elevated levels of neurotoxic 1-deoxysphingolipids (1-dSLs). However, retina-specific, disease-contributing factors have yet to be identified. Here, we used iPSC-differentiated retinal pigmented epithelial (iRPE) cells derived from donors with or without MacTel to screen for novel cell-intrinsic pathological mechanisms. We show that MacTel iRPE cells mimicked the low serine levels observed in serum from patients with MacTel. Through RNA-Seq and gene set enrichment pathway analysis, we determined that MacTel iRPE cells are enriched in cellular stress pathways and dysregulation of central carbon metabolism. Using respirometry and mitochondrial stress testing, we functionally validated that MacTel iRPE cells had a reduction in mitochondrial function that was independent of defects in serine biosynthesis and 1-dSL accumulation. Thus, we identified phenotypes that may constitute alternative disease mechanisms beyond the known serine/sphingolipid pathway.

Imaging endpoints for clinical trials in MacTel type 2.

INTRODUCTION: Macular Telangiectasia type 2 (MacTel) is a bilateral neurodegenerative disease associated with dysfunction in the serine and lipid metabolism resulting in loss of Muller cells and photoreceptors. Typical structural changes include vascular abnormalities, loss of retinal transparency, redistribution of macular pigment and thinning of the central retina with photoreceptor loss. The presence and extent of photoreceptor loss, as visible on Optical Coherence Tomography (OCT) ("disease severity scale"), correlate with functional loss and the limitation of photoreceptor loss appears to be the most promising therapeutic approach. Ongoing clinical trials of ciliary neurotrophic factor (CNTF) implants for the treatment of MacTel are using this outcome to evaluate efficacy. An ideal outcome measure provides the ability to quantify the extent of the disease progression with precision and reproducibility. METHODS: This review describes the changes and findings on different imaging techniques including fluorescein- and OCT angiography, blue light reflectance, 1- and 2-wavelength autofluorescence and OCT. RESULTS: The possibilities of objective quantification of the severity of MacTel and correlation with functional characteristics such as best-corrected visual acuity (BCVA) and microperimetry and their applications as quantitative imaging endpoints for clinical treatment trials are discussed. OCT and especially en face OCT could be demonstrated as precise and reproducible methods to quantify the area of photoreceptor loss, which correlated highly significantly with functional loss in microperimetry. CONCLUSION: The analysis of the area of photoreceptor loss on en face OCT is the most reliable imaging endpoint for treatment trials in MacTel. This method is already being used in ongoing randomized trials.

Identification of genetic factors influencing metabolic dysregulation and retinal support for MacTel, a retinal disorder.

Macular Telangiectasia Type 2 (MacTel) is a rare degenerative retinal disease with complex genetic architecture. We performed a genome-wide association study on 1,067 MacTel patients and 3,799 controls, which identified eight novel genome-wide significant loci (p < 5 × 10-8), and confirmed all three previously reported loci. Using MAGMA, eQTL and transcriptome-wide association analysis, we prioritised 48 genes implicated in serine-glycine biosynthesis, metabolite transport, and retinal vasculature and thickness. Mendelian randomization indicated a likely causative role of serine (FDR = 3.9 × 10-47) and glycine depletion (FDR = 0.006) as well as alanine abundance (FDR = 0.009). Polygenic risk scoring achieved an accuracy of 0.74 and was associated in UKBiobank with retinal damage (p = 0.009). This represents the largest genetic study on MacTel to date and further highlights genetically-induced systemic and tissue-specific metabolic dysregulation in MacTel patients, which impinges on retinal health.

Subretinal Mononuclear Cells in Coats' Disease Studied with RPE65 and CD163: Evidence for Histiocytoid Pigment Epithelial Cells.

PURPOSE: To evaluate the mononuclear cells in the subretinal exudate in Coats' disease. DESIGN: Retrospective case series. METHODS: Five enucleated globes and 1 cytology sample from a patient with Coats' disease and 1 case of chronic retinal detachment following repair of an open globe injury were examined immunohistochemically to identify intraretinal and subretinal exudative cells. The 2 biomarkers were RPE65 for retinal pigment epithelium and CD163 for histiocytes, each tagged with different chromogens, yellow for pigment epithelium and purple for CD163-positive (CD163+) monocytes/histiocytes. Expression levels were sought from both biomarkers together and singly. A color shift to red in the cells' chromogenic reaction indicated the simultaneous presence of the 2 biomarkers. RESULTS: Most of the mononuclear cells in Coats' disease samples were CD163+ (purple), and a minority were RPE65+ (yellow). An intermediate number of cells were RPE65+/CD163+ (orange-red). The eye with a chronic retinal detachment had an equal distribution of CD163+ and RPE65+/CD163+ cells. CONCLUSIONS: RPE has several well-delineated phenotypes and functions. In normal visual physiology, the pigment epithelium supports photoreceptors and participates in their renewal by phagocytosis of the tips of the photoreceptors. The expression of CD163, a feature of hematopoietically derived monocytes, together with RPE65 in the retinal pigment epithelium, supports differentiation toward histiocytes. Yellow staining of detached pigment epithelial cells were rare. The presence of histiocytoid pigment epithelium at the Bruch membrane probably also has implications for macular degeneration.

Aqueous humour cytokines profiles in eyes with Coats disease and the association with the severity of the disease.

BACKGROUND: To investigate aqueous humour (AH) cytokine profiles in eyes with Coats disease and analyze the association between cytokine concentrations and the severity of the disease. METHODS: The study included 36 patients (36 eyes) with Coats disease and 15 control patients (15 eyes) with congenital cataract. AH samples were obtained preoperatively and the concentrations of 22 different cytokines were measured through Cytometric Bead Array technology. Clinical characteristics of Coats disease, including the extent of retinal exudation and exudative retinal detachment (ERD), were recorded for analysis. RESULTS: The concentrations of 8 cytokines (VEGF, IL-6, IL-8, MCP-1, MIP-1α, IP-10, VCAM-1 and ICAM-1) were significantly higher in the Coats disease group than in the control group (all P < 0.002). Except for VCAM-1 and ICAM-1, the concentration of the other cytokines listed above showed a significant increase from stage 2 to stage 3 (all P < 0.05). Meanwhile, the concentrations of VEGF, IL-8, MCP-1 and MIP-1α showed a significant and positive association with the extent of retinal exudation and ERD (all r > 0.4, P < 0.05). Among these, IL-8 showed a strong association with the extent of retinal exudation and ERD (all r > 0.7, P < 0.001). The concentrations of IL-1α, IL-1ß, IL-2, IL-4, IL-5, IL-10, IL-12, Fractalkine, RANTES, G-CSF and GM-CSF were very low in both groups. CONCLUSIONS: Various cytokines in the AH, including elevated VEGF, IL-6, IL-8, MCP-1, MIP-1α, IP-10, VCAM-1 and ICAM-1, may be involved in the pathogenesis and progression of Coats disease. Increasing severity of Coats disease is significantly associated with the AH concentrations of VEGF, IL-8, MCP-1 and MIP-1α. Further clinical treatment aimed to reduce vascular leakage and antagonize neovascularization and inflammation may be useful in preventing the progression of Coats disease.

FLUORESCENCE LIFETIME PATTERNS IN MACULAR TELANGIECTASIA TYPE 2.

PURPOSE: Type 2 idiopathic macular telangiectasia (MacTel) is a rare bilateral neurodegenerative disease characterized by alterations in the macular capillary network leading to central vision loss. The purpose of this study was to quantify disease-specific retinal fluorescence lifetime patterns in patients with MacTel using fluorescence lifetime imaging ophthalmoscopy. PARTICIPANTS: Both eyes of 14 patients (mean age ± SEM, 67.8 ± 6.4 years) with a clinical diagnosis of MacTel Type 2 and 14 healthy age-matched controls (age 69.8 ± 6.4 years) were included in this study. METHODS: All participants were imaged with a fluorescence lifetime imaging ophthalmoscope (Heidelberg Engineering, Germany). Mean retinal fluorescence lifetimes (Tm) were obtained in the short spectral channels (498-560 nm) and long spectral channels (560-720 nm). Clinical features, fundus images, fundus autofluorescence intensity images, spectral domain optical coherence tomography, and corresponding macular pigment optical density measurements using a modified confocal scanning laser ophthalmoscope (mpHRA) were further analyzed. Patients were classified into five phenotypic subgroups using the Gass and Blodi classification. RESULTS: Mean fluorescence lifetimes were significantly prolonged temporal to the fovea in patients with MacTel compared with healthy controls (mean ± SEM: short spectral channels 543 ± 61 ps vs. 304 ± 9 ps; P < 0.0001; long spectral channels: 447 ± 26 ps vs. 348 ± 11 ps; P < 0.0001), and appeared as a crescent or ring-shaped pattern. Prolonged lifetime patterns correlated with decreased macular pigment density on macular pigment optical density measurements. Follow-up examinations were performed in four MacTel patients, which revealed an increase of short spectral channel Tm of 22% over 2.1 years in the temporal fovea. CONCLUSION: This study confirms that fundus autofluorescence lifetimes display characteristic patterns in patients with MacTel Type 2 disease and provide information about macular pigment and possibly photoreceptor loss. Fluorescence lifetime prolongation correlates with disease severity and may therefore be a useful addition to other imaging modalities for assessing disease progression in MacTel Type 2.

Serine and Lipid Metabolism in Macular Disease and Peripheral Neuropathy.

BACKGROUND: Identifying mechanisms of diseases with complex inheritance patterns, such as macular telangiectasia type 2, is challenging. A link between macular telangiectasia type 2 and altered serine metabolism has been established previously. METHODS: Through exome sequence analysis of a patient with macular telangiectasia type 2 and his family members, we identified a variant in SPTLC1 encoding a subunit of serine palmitoyltransferase (SPT). Because mutations affecting SPT are known to cause hereditary sensory and autonomic neuropathy type 1 (HSAN1), we examined 10 additional persons with HSAN1 for ophthalmologic disease. We assayed serum amino acid and sphingoid base levels, including levels of deoxysphingolipids, in patients who had macular telangiectasia type 2 but did not have HSAN1 or pathogenic variants affecting SPT. We characterized mice with low serine levels and tested the effects of deoxysphingolipids on human retinal organoids. RESULTS: Two variants known to cause HSAN1 were identified as causal for macular telangiectasia type 2: of 11 patients with HSAN1, 9 also had macular telangiectasia type 2. Circulating deoxysphingolipid levels were 84.2% higher among 125 patients with macular telangiectasia type 2 who did not have pathogenic variants affecting SPT than among 94 unaffected controls. Deoxysphingolipid levels were negatively correlated with serine levels, which were 20.6% lower than among controls. Reduction of serine levels in mice led to increases in levels of retinal deoxysphingolipids and compromised visual function. Deoxysphingolipids caused photoreceptor-cell death in retinal organoids, but not in the presence of regulators of lipid metabolism. CONCLUSIONS: Elevated levels of atypical deoxysphingolipids, caused by variant SPTLC1 or SPTLC2 or by low serine levels, were risk factors for macular telangiectasia type 2, as well as for peripheral neuropathy. (Funded by the Lowy Medical Research Institute and others.).

Contrast sensitivity and visual acuity under low light conditions in macular telangiectasia type 2.

BACKGROUND/AIM: Macular pigment optical density (MPOD) is centrally depleted early on in macular telangiectasia type 2 (MacTel). Contrast sensitivity (CS) might be related to MPOD, and thus impaired in early MacTel. The effect of low luminance was assessed on both CS and best corrected visual acuity (BCVA). METHODS: This is a cross-sectional study. Pelli-Robson charts were used for CS testing at 1 m in photopic (110 lux) and mesopic (1 lux) conditions. BCVA was tested with ETDRS charts and low luminance visual acuity (LLVA) with a 2.0 log unit neutral density filter. MPOD was obtained with dual-wavelength autofluorescence. RESULTS: One hundred and three eyes of 52 patients with MacTel (mean±SD age 62.9±10.2, range 35-77) were compared with 34 healthy eyes of 17 controls (mean±SD age 65.2±7.4, range 53-78). CS was significantly lower in the eyes with MacTel. This impairment was higher in low light conditions (low light contrast sensitivity (LL-CS)). Eyes at the early stages of MacTel had significantly lower LL-CS than controls, but normal (photopic) CS. The results were similar but less pronounced for BCVA/LLVA. Decrease in CS was correlated with loss of MPOD. CONCLUSIONS: Low light conditions have a detrimental effect on visual performance in MacTel. Impaired CS might correlate with MPOD depletion as a pathognomonic finding in MacTel. Functional impairment might precede structural disintegration, indicating dysfunction at the cellular level. The applied tests might be useful as additional functional assessments in clinical routine and as outcome measures in future interventional clinical trials.

Associations of cytokine concentrations in aqueous humour with retinal vascular abnormalities and exudation in Coats' disease.

PURPOSE: To investigate the associations of cytokine concentrations in aqueous humour with the severity of retinal vascular abnormalities, exudation and fibrosis in patients with Coats' disease. METHODS: Aqueous humour samples were collected in 23 paediatric patients (23 eyes) with Coats' disease and six age-matched control patients (six eyes) with congenital cataract in this cross-sectional, case-control study. Through Cytometric Bead Array technology, six angiogenic, inflammatory and fibrotic cytokines were measured for their concentrations in aqueous humour. Ophthalmologic characteristics including retinal vessel abnormalities, exudation and fibrosis of Coats' disease were also clinically evaluated for analysis. RESULTS: The aqueous levels of vascular endothelial growth factor (VEGF) (p = 0.006) and monocyte chemoattractant protein-1 (MCP-1) (p < 0.001) were significantly higher in the Coats' disease group than in the control group. The concentrations of angiogenin were peaked in eyes with first-grade vessels tortuosity (p < 0.001), and also positively correlated with the severity of retinal capillary abnormalities (r = 0.910, p < 0.001). The concentrations of MCP-1 (r = 0.966, p < 0.001) and VEGF (r = 0. 765, p = 0.002) were significantly correlated with the extent of retinal exudation. The aqueous humour transforming growth factor-ß (TGFß) concentrations were higher in eyes with retinal fibrosis than in non-fibrotic eyes with Coats' disease (p = 0.004). CONCLUSION: In Coats' disease, angiogenin may act as a potential biomarker for retinal vascular abnormalities. The concentrations of VEGF and MCP-1 may positively correlate with the severity of retinal exudation.

Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO) of Macular Pigment.

Purpose: To describe different patterns of macular pigment (MP) seen in fluorescence lifetime imaging ophthalmoscopy (FLIO) and to analyze ex vivo fluorescence characteristics of carotenoids. Methods: A total of 31 eyes of young healthy subjects, 4 eyes from patients with albinism, 36 eyes with macular telangiectasia type 2 (MacTel), 24 eyes with retinitis pigmentosa, and 1 eye with a macular hole were included in this clinic-based, cross-sectional study. All subjects underwent Heidelberg Engineering FLIO and MP measurements (dual-wavelength autofluorescence). Fundus autofluorescence (FAF) lifetimes of a 30° retinal field were detected in two spectral channels (SSC: 498-560 nm; LSC: 560-720 nm), and amplitude-weighted mean fluorescence lifetimes (τm) were calculated. Additionally, autofluorescence lifetimes of known dilutions of lutein and zeaxanthin were measured in a cuvette in free- and protein-associated states. Results: MP shows a significant inverse correlation to foveal FAF lifetimes measured with FLIO (SSC: r = -0.608; P < 0.001). Different distribution patterns can be assigned to specific disease-related changes. Two patients with albinism, who did not have MP, were found to be missing short FAF lifetimes. In solvent, lutein and zeaxanthin show very short autofluorescence lifetimes (∼50-60 ps; SSC), as do their respective binding proteins (∼40-50 ps; SSC). When combining carotenoids with their specific binding proteins, the decay times shift to longer means (∼70-90 ps; SSC). Conclusions: This study expands upon previous findings of an impact of MP on short FAF lifetimes by describing ex vivo autofluorescence lifetimes of carotenoids and different in vivo autofluorescence patterns that can be associated with certain diseases.

Macular Pigment Distribution as Prognostic Marker for Disease Progression in Macular Telangiectasia Type 2.

PURPOSE: To evaluate macular pigment distribution pattern as a prognostic marker for disease progression in patients with macular telangiectasia type 2 (MacTel). DESIGN: Retrospective cohort study. METHODS: In this single-center study, 90 eyes of 47 patients were analyzed. Macular pigment optical density (MPOD) was measured with dual-wavelength fundus autofluorescence. Eyes were graded into MPOD distribution classes 1 to 3 with increasing loss of macular pigment and grading was performed masked by 2 independent graders. Best-corrected visual acuity, reading acuity, total scotoma size in fundus-controlled perimetry (microperimetry), and break of the ellipsoid zone (EZ) in optical coherence tomography (en face measurement) were defined as functional and morphologic outcome parameters and evaluated at baseline and after 60 months. RESULTS: After a mean review period of 59.6 months (±standard deviation 5.2 months), no change between MPOD classes was observed compared to baseline. Morphologic and functional deficits were limited to the area of MPOD loss. At last follow-up, a significant mean decrease of visual acuity and reading acuity as well as a significant mean increase of scotoma size and EZ break were observed in eyes assigned to MPOD classes 2 and 3, while outcome parameters remained stable in eyes of class 1. CONCLUSIONS: The results indicate that MPOD and its distribution may serve as a prognostic marker for disease progression and functional impairment in patients with MacTel.

Conditional Müller Cell Ablation Leads to Retinal Iron Accumulation.

Purpose: Retinal iron accumulation is observed in a wide range of retinal degenerative diseases, including AMD. Previous work suggests that Müller glial cells may be important mediators of retinal iron transport, distribution, and regulation. A transgenic model of Müller cell loss recently demonstrated that primary Müller cell ablation leads to blood-retinal barrier leakage and photoreceptor degeneration, and it recapitulates clinical features observed in macular telangiectasia type 2 (MacTel2), a rare human disease that features Müller cell loss. We used this mouse model to determine the effect of Müller cell loss on retinal iron homeostasis. Methods: Changes in total retinal iron levels after Müller cell ablation were measured using inductively coupled plasma mass spectrometry. Corresponding changes in the expression of iron flux and iron storage proteins were determined using quantitative PCR, Western analysis, and immunohistochemistry. Results: Müller cell loss led to blood-retinal barrier breakdown and increased iron levels throughout the neurosensory retina. There were corresponding changes in mRNA and/or protein levels of ferritin, transferrin receptor, ferroportin, Zip8, and Zip14. There were also increased iron levels within the RPE of retinal sections from a patient with MacTel2 and both RPE and neurosensory retina of a patient with diabetic retinopathy, which, like MacTel2, causes retinal vascular leakage. Conclusion: This study shows that Müller cells and the blood-retinal barrier play pivotal roles in the regulation of retinal iron homeostasis. The retinal iron accumulation resulting from blood-retinal barrier dysfunction may contribute to retinal degeneration in this model and in diseases such as MacTel2 and diabetic retinopathy.

MACULAR PIGMENT DISTRIBUTION RESPONSES TO HIGH-DOSE ZEAXANTHIN SUPPLEMENTATION IN PATIENTS WITH MACULAR TELANGIECTASIA TYPE 2.

PURPOSE: To analyze macular pigment (MP) amount and distribution in patients with macular telangiectasia Type 2 receiving oral zeaxanthin supplementation in a randomized, open-label, interventional trial. METHODS: Eight macular telangiectasia Type 2 patients were randomized to 10 mg or 20 mg of zeaxanthin per day. At each visit, best-corrected visual acuity, contrast sensitivity, fundus biomicroscopy, color fundus photography, autofluorescence imaging, optical coherence tomography, and serum carotenoid levels were tested. Patients were assessed at baseline and after 6, 12, 18, and 24 months of zeaxanthin supplementation. Concentration of MP was analyzed and calculated from autofluorescence imaging obtained at 488-nm excitation wavelength. Serum carotenoid levels were obtained using high-performance liquid chromatography. RESULTS: The majority of patients had definite increases in the intensity of hypofluorescent ring of MP, but none of them deposited MP centrally at the fovea. Although some patients noted subjective improvements in vision, no objective improvements could be documented, and there were no changes in foveal optical coherence tomographic features. Yellowish, hypofluorescent crystals appeared in one patient's macular region with no change in visual acuity. These inner retinal crystals disappeared several months after discontinuing her 20-mg zeaxanthin supplement. CONCLUSION: Based on the current study, zeaxanthin supplementation does not result in any visual benefit in patients with macular telangiectasia Type 2 and does not reestablish a normal peaked distribution of MP in the fovea. One patient developed a novel, reversible, crystalline maculopathy in response to zeaxanthin supplementation that was reminiscent of canthaxanthin crystalline maculopathy.

Differences in aqueous concentrations of cytokines in paediatric and adult patients with Coats' disease.

PURPOSE: To investigate the differential aqueous concentrations of vascular endothelia growth factor (VEGF) and inflammatory cytokines in paediatric and adult patients with Coats' disease. METHODS: A total of 20 eyes of 20 patients with Coats' disease, 12 eyes of 12 paediatric patients, and eight eyes of eight adult patients, six patients (six eyes) with congenital cataract as the paediatric control group and 10 patients (10 eyes) with senile cataract as the adult control group were examined. Aqueous humour samples were assessed for interleukin-6, -8, -1ß (IL-6, IL-8, IL-1ß, respectively), basic fibroblast growth factor, monocyte chemo-attractant protein 1, tumour necrosis factor alpha and VEGF by multiplex bead assay. RESULTS: Significantly, higher concentrations of VEGF, IL-6 and IL-1ß were found in the paediatric patients with Coats' disease (p = 0.001, p = 0.004 and p = 0.006). Concentration of VEGF in the paediatric patients with Stage 3B of Coats' disease was significantly higher than that of Stage 3A (p = 0.010). In the adult patients with Coats' disease, the aqueous levels of IL-6 and IL-1ß were significantly higher than that of the controls (p = 0.012, and p = 0.005). The concentration of IL-6 was significantly linearly associated with the extent of exudative retinal detachment (p = 0.003, R = 0.892). CONCLUSIONS: Increasing severity of Coats' disease is significantly associated with intraocular VEGF concentration in the paediatric patients. And IL-6 may be involved with the inflammatory process in the adult patients with Coats' disease.

iTRAQ-Based Proteomics Investigation of Aqueous Humor from Patients with Coats' Disease.

BACKGROUND: Coats' disease is an uncommon form of retinal telangiectasis, and the identification of novel proteins that contribute to the development of Coats' disease is useful for improving treatment efficacy. Proteomic techniques have been used to study many eye diseases; however, few studies have used proteomics to study the development of Coats' disease. METHODS: Isobaric tagging for relative and absolute protein quantification (iTRAQ) was employed to screen differentially expressed proteins (DEPs) in the aqueous humor (AH) between stage 3A patients (n = 8), stage 3B patients (n = 14), stage 4 patients (n = 2) and control patients (n = 20). Differentially co-expressed proteins (DCPs) were present in all three stages of Coats' disease and were considered disease-specific proteins. These proteins were further analyzed using Gene Ontology (GO) functional annotations. RESULTS: A total of 819 proteins were identified in the AH, 222 of which were significantly differentially expressed (fold change > 2 and P < 0.05) in the samples from at least one stage of Coats' disease. Of the DEPs, 46 were found among all three stages of Coats' disease and the controls; therefore, they were considered Coats' disease-specific proteins (DCPs). A GO classification analysis indicated that the DCPs were closely related to structural molecule activity, cell adhesion molecule binding and receptor binding. Western blotting confirmed the expression levels of haptoglobin and apolipoprotein C-I were significantly up-regulated in Coats' disease. CONCLUSIONS: The 46 Coats' disease-specific proteins may provide additional insights into the mechanism of Coats' disease and represent potential biomarkers for identifying individuals with Coats' disease.

CORRELATION OF OPTICAL COHERENCE TOMOGRAPHY AND MACULAR PIGMENT OPTICAL DENSITY MEASUREMENTS IN TYPE 2 IDIOPATHIC MACULAR TELANGIECTASIA.

PURPOSE: Macular telangiectasia is associated with neurodegenerative changes including focal outer retinal atrophy and a loss of macular pigment (MP). We aimed to investigate whether an association between spectral domain optical coherence tomography neurodegenerative signs and MP abnormalities can be detected. METHODS: Forty-seven eyes of 27 macular telangiectasia Type 2 patients (mean age 66.7 years, range 50-82 years, 12 male) were investigated. An MP pattern was recorded using a dual-wavelength autofluorescence method and classified according to severity (I-III). Outer plexiform, inner nuclear, and photoreceptor layer thickness values were measured in Spectralis spectral domain optical coherence tomography scans. Thickness values were compared with those of a control group of 14 healthy age-matched eyes. RESULTS: Macular pigment redistribution was found to be Class I in 11 eyes, Class II in 28 eyes, and Class III in 8 eyes. More advanced stages of MP loss were associated with a greater, statistically significant thinning of the outer plexiform and inner nuclear layer complex and photoreceptor layers (P ≤ 0.001). Lower absolute levels of MP were also associated with a thinning of the photoreceptor layer. Thinning was restricted to within the parafovea, more severe at temporal eccentricities. CONCLUSION: Our findings support the hypothesis that in macular telangiectasia Type 2 cellular degenerative processes leading to a thinning of these layers also result in reduction and redistribution of MP.

ASSOCIATION BETWEEN CHANGES IN MACULAR VASCULATURE IN OPTICAL COHERENCE TOMOGRAPHY- AND FLUORESCEIN- ANGIOGRAPHY AND DISTRIBUTION OF MACULAR PIGMENT IN TYPE 2 IDIOPATHIC MACULAR TELANGIECTASIA.

PURPOSE: We investigate the association between morphologic findings in optical coherence tomography angiography (OCTA) as a new method offering the visualization of deeper layers of retinal vasculature and fluorescein angiography (FA) and macular pigment imaging and in Type 2 macular telangiectasia. METHODS: Fourty-two eyes of 21 patients with macular telangiectasia (38-68 years, 14 female) were examined by FA and OCTA and 24 eyes additionally with dual-wavelength autofluorescence. Early and late FA, macular pigment density images, and (after segmentation of retinal vasculature into superficial and deep capillary network and outer) OCTA images were graded into standardized categories. Agreement between the methods was evaluated statistically. RESULTS: In OCTA, a reduction of density of superficial capillaries, dilated vessels in the deep capillary network, anastomoses toward the superficial capillary network, and "new" vessels in the outer retina layers can be detected. The described anatomical features, especially in the deep capillary plexus and outer retina corresponded well with changes in FA. Classes of macular pigment distribution correlated most with classes of changes in OCTA superficial capillary plexus. CONCLUSION: Progressive changes in macular telangiectasia apparent in FA and macular pigment imaging are most obvious in the deep capillary network and outer retina in OCTA. Optical coherence tomography angiography offers a noninvasive technology to analyze vascular changes in the retina and choroid of patients with macular telangiectasia.