Differential gene expression analysis of corneal endothelium indicates involvement of phagocytic activity in Fuchs' endothelial corneal dystrophy.

Fuchs' endothelial corneal dystrophy (FECD) is a progressive vision impairing disease caused by thickening of Descemet's membrane and gradual degeneration and loss of corneal endothelial cells. The aim of this study was to identify differentially expressed genes between FECD-affected and unaffected corneal endothelium to gain insight into the pathophysiological mechanisms underlying this disease. Microarray gene expression analysis was performed on total RNA from FECD-affected and unaffected corneal endothelium-Descemet's membrane (CE-DM) specimens using the Illumina HumanHT-12 v4.0 expression array. RNA from pools of FECD-affected (n = 3 per pool) and individual unaffected (n = 3) specimens was used for comparison. Altered expression of a sub-set of differentially expressed genes was validated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) in independent specimens. Bioinformatics analysis was performed using InnateDB to reveal functional relationships among the differentially expressed genes and molecular pathways involved in the disease. A total of 16,513 genes were found expressed in the corneal endothelium of which 142 genes were differentially expressed between FECD-affected and unaffected endothelium (log2 fold-change ≥1.5, corrected p-value ≤0.05). Most of the genes were up-regulated (126) and a small proportion down-regulated (16) in affected corneal endothelium. Of the twelve genes prioritised for validation, differential expression of 10 genes, including those ranked 57th and 81st by significance validated by qRT-PCR (8 up-regulated and 2 downregulated, corrected p ≤ 0.05), one gene showed a trend for up-regulation in affected endothelium, consistent with the microarray analysis and another was up-regulated in an independent study indicating robustness of the differential expression dataset. Bioinformatic analysis revealed significant over-representation of differentially expressed genes in extracellular matrix reorganisation, cellular remodelling, immune response, and inflammation. Network analysis showed functional inter-relatedness of the majority of the dysregulated genes and revealed known direct functional relationships between 20 of the genes; many of these genes have roles in macrophage differentiation, phagocytosis and inflammation. This is the second report of microarray gene expression analysis in FECD. This study revealed a set of highly dysregulated genes in the corneal endothelium in FECD. More than a third of the dysregulated genes in the disease have been discovered for the first time and thus are novel. The dysregulated genes strongly suggest the presence of phagocytic cells, most likely immune cells, and inflammation in corneal endothelium in the disease. This study provides a molecular framework for delineating the mechanisms underlying these cellular processes in FECD.

Person-centered, non-pharmacological intervention in reducing psychotropic medications use among residents with dementia in Australian rural aged care homes.

BACKGROUND: High rates of psychotropic medications are prescribed in aged care homes despite their limited effectiveness and associated adverse effects. We aim to evaluate the changes in prescription patterns for elderly residents with dementia in the 'Harmony in the Bush Dementia Study'. Harmony in the Bush is a person-centered model of dementia care in nursing homes, based on the principles of Progressively Lowered Stress Threshold and person-centered music intervention. METHODS: Our larger study (12 weeks period) was a quasi-experimental design conducted in five rural nursing homes in Australia. Medication charts (n = 31) were collected retrospectively from three rural aged care facilities. Medication data for each resident was collected from a three-month medication charts, pre-intervention, and post-intervention. Fifty-three staff participated in 31 semi-structured interviews and 8 focus groups at post-intervention, and at 1-month and 3-months follow up. RESULTS: The median age of the participants was 83 years, and 68% of them were female. Polypharmacy was measured in 87% (n = 27) of the participants. Hypertension, hyperlipidemia, diabetes, and the Alzheimer's disease were the major comorbidities identified in residents. None of the residents received more than the maximum dose of psychotropic medications recommended by the guidelines. There was a reduction of 22.4% (77.4% vs 55%) in the use of at least any psychotropic medications, 19.6% (39% vs, 19.4%) reduction in antipsychotics and benzodiazepines (39% vs 19.4%), and 6.5% (42% vs 35.5%) reduction in antidepressants prescription medicines, when comparing residents' medication charts data covering 3-months pre- and post-intervention, however, these changes were not statistically significant. Additionally, there was a decreasing trend in the use of inappropriate medications. Psychotropic medications were prescribed in up to 43% and anti-dementia medications in 44% of participants for more than 6 months. Three themes extracted from qualitative data include decrease behavioral and psychiatric symptoms of dementia due to medication weaning or dose tapering, other strategies to reduce medication use, and environmental or noise control. CONCLUSIONS: Our findings indicate that the Harmony in the Bush model as a non-pharmacological approach reduces the prescription of psychotropic medications in rural nursing homes as supported by findings from both quantitative and qualitative data. TRIAL REGISTRATION: ANZCTR, ACTRN12618000263291 . Registered on 20th February 2018.

The outcomes of a person-centered, non-pharmacological intervention in reducing agitation in residents with dementia in Australian rural nursing homes.

BACKGROUND: There is limited best- practice evidence to address behavioral and psychiatric symptoms for those with dementia in Australian rural nursing homes. This study aims to evaluate the outcomes of a person-centered, non-pharmacological dementia care model, 'Harmony in the Bush', based on the Progressively Lowered Stress Threshold principles and person-centered music in rural Australia. METHODS: A quasi-experimental (nonrandomized, pre-post) intervention study was conducted in five rural nursing homes in Queensland and South Australia. Seventy-four residents with dementia participated in this intervention study, which yielded a sample power of 80%. Eighty-seven staff completed the Caregiver Stress Inventory at pre-post four-weeks of intervention. Staff training workshops focused on the theory of the Progressively Lowered Stress Threshold principles and delivery of person-centered care plan with integrated music intervention. We used reported changes in agitation of the residents, measured using Cohen- Mansfield Agitation Inventory, and staff's caregiving stress, using Caregivers Stress Inventory. This study adheres to the CONSORT guidelines. RESULTS: Mean age of residents with dementia was 82.4 (7.7) years and 69% were females. The mean age of admission was 80.1(8.4) years. Baseline measures indicated that 32.7% had mild- severe pain and 30.5% reported mild-severe sadness. The results showed statistically significant decline in aggressive behaviors, physically non-aggressive behaviors, verbally agitated behavior and hiding and hoarding. There was similar reduction in staff stress in the domains of aggressive behaviors, inappropriate behaviors, resident safety, and resource deficiency. CONCLUSIONS: The Harmony in the Bush model is effective in reducing agitation among dementia residents with significant reduction in staff stress levels in nursing homes in rural Australia. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry (ANZCTR) on 20/2/2018 (Registration No: ACTRN12618000263291p). https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374458.

Personalised music for residents with dementia in an Australian rural aged-care setting.

OBJECTIVE: Personalised music reportedly has a positive effect on behaviour and mood in people living with dementia. This intervention has not been conducted in low-resourced or rural aged-care settings. We evaluated the effect of a non-therapist-led personalised music listening intervention on residents with dementia and workplace culture in a rural aged-care facility in South Australia. DESIGN: Qualitative pilot study. SETTING: Rural aged-care home in South Australia. PARTICIPANTS: Ten residents with dementia and 15 aged-care staff participated in this study. INTERVENTIONS: Ten residents participated in an 8-week music program. Four focus groups were conducted with aged-care staff post-intervention. A thematic analysis was used to identify emerging themes. MAIN OUTCOME MEASURE: Personalised music positively influenced resident's behaviour and well-being, social interaction and the workplace environment and culture, and served as a useful tool for personalised care. RESULTS: Three themes emerged: quality of life, personalised care and better aged-care environment. Personalised music positively influenced resident's behaviour and well-being, social interaction and the workplace environment and culture, and served as a useful tool for personalised care. CONCLUSION: Personalised music program is an effective, low-cost intervention to improve quality of life and personalised care of residents living with dementia, staff well-being, and a workplace and culture in low-resourced or rural aged-care settings.

The genetic and clinical landscape of nanophthalmos and posterior microphthalmos in an Australian cohort.

Nanophthalmos and posterior microphthalmos are ocular abnormalities in which both eyes are abnormally small, and typically associated with extreme hyperopia. We recruited 40 individuals from 13 kindreds with nanophthalmos or posterior microphthalmos, with 12 probands subjected to exome sequencing. Nine probands (69.2%) were assigned a genetic diagnosis, with variants in MYRF, TMEM98, MFRP, and PRSS56. Two of four PRSS56 families harbored the previously described c.1066dupC variant implicated in over half of all reported PRSS56 kindreds, with different surrounding haplotypes in each family suggesting a mutational hotspot. Individuals with a genetic diagnosis had shorter mean axial lengths and higher hyperopia than those without, with recessive forms associated with the most extreme phenotypes. These findings detail the genetic architecture of nanophthalmos and posterior microphthalmos in a cohort of predominantly European ancestry, their relative clinical phenotypes, and highlight the shared genetic architecture of rare and common disorders of refractive error.

Reduced expression of apolipoprotein E and immunoglobulin heavy constant gamma 1 proteins in Fuchs endothelial corneal dystrophy.

BACKGROUND: Fuchs endothelial corneal dystrophy (FECD) is a progressive and potentially a sight threatening disease, and a common indication for corneal grafting in the elderly. Aberrant thickening of Descemet's membrane, formation of microscopic excrescences (guttae) and gradual loss of corneal endothelial cells are the hallmarks of the disease. The aim of this study was to identify differentially abundant proteins between FECD-affected and unaffected Descemet's membrane. METHODS: Label-free quantitative proteomics using nanoscale ultra-performance liquid chromatography-mass spectrometry (nUPLC-MSE ) was employed on affected and unaffected Descemet's membrane extracts, and interesting findings were further investigated using quantitative reverse transcription-polymerase chain reaction and immunohistochemical techniques. RESULTS: Quantitative proteomics revealed significantly lower abundance of apolipoprotein E (APOE) and immunoglobulin heavy constant gamma 1 protein (IGHG1) in affected Descemet's membrane. The difference in the distribution of APOE between affected and unaffected Descemet's membrane and of IGHG1 detected by immunohistochemistry support their down-regulation in the disease. Comparative gene expression analysis showed significantly lower APOE mRNA levels in FECD-affected than unaffected corneal endothelium. IGHG1 gene is expressed at extremely low levels in the corneal endothelium, precluding relative expression analysis. CONCLUSIONS: This is the first study to report comparative proteomics of Descemet's membrane tissue, and implicates dysregulation of APOE and IGHG1 proteins in the pathogenesis of Fuchs endothelial corneal dystrophy.

Person-Centred, Culturally Appropriate Music Intervention to Improve Psychological Wellbeing of Residents with Advanced Dementia Living in Australian Rural Residential Aged Care Homes.

This quasi-experimental, nonrandomized intervention study reports the effect of person-centred, culturally appropriate music on psychological wellbeing of residents with advanced dementia in five rural residential aged care homes in Australia. Seventy-four residents attended in person-centred music sessions and culturally appropriate group sessions. Interest, response, initiation, involvement, enjoyment, and general reactions of the residents were assessed using the Music in Dementia Assessment Scale (MiDAS), and interviews and focus groups were conducted with aged care staff and musicians. The overall effect of person-centred sessions at two-time points were: during the intervention-351.2 (SD 93.5); and two-hours post intervention-315.1 (SD 98.5). The residents presented a moderate to high level of interest, response, initiation, involvement, and enjoyment during the session and at post-intervention. However, the MiDAS sub-categories' mean scores differed between the time-points: interest (t59 = 2.8, p = 0.001); response (t59 = 2.9, p = 0.005); initiation (t59 = 2.4, p = 0.019); and involvement (t59 = 2.8, p = 0.007), indicating a significant decline in the effect of person-centred music over time. Interestingly, during the period of time, most of the residents were observed with no exhibitions of agitation (87.5%), low in mood (87.5%), and anxiousness (70.3%), and with a presentation of relaxation (75.5%), attentiveness (56.5%), and smiling (56.9%). Themes from qualitative data collected regarding culturally appropriate group music sessions were behavioural change, meaningful interaction, being initiative, increased participation, and contentment. The findings suggest that the integration of music into care plans may reduce the residents' agitation and improve their emotional wellbeing in rural aged care homes.

RNA Sequencing of Lens Capsular Epithelium Implicates Novel Pathways in Pseudoexfoliation Syndrome.

Purpose: Pseudoexfoliation syndrome (PEX) is a common systemic disease that results in severe and often irreversible vision loss. Despite considerable research effort, PEX remains incompletely understood. This study sought to perform the first RNAseq study in elucidate the pathophysiology of PEX, and contribute a publicly available transcriptomic data resource for future research. Methods: Human ocular lens capsular epithelium samples were collected from 25 patients with PEX and 39 non-PEX controls undergoing cataract surgery. RNA extracted from these specimens was subjected to polyadenylated (mRNA) selection and deep bulk RNA sequencing. Differential expression analysis investigated protein-coding gene transcripts. Exploratory analyses used pathway analysis tools, and curated class- and disease-specific gene sets. Results: Differential expression analysis demonstrated that 2882 genes were differentially expressed according to PEX status. Genes associated with viral gene expression pathways were among the most upregulated, alongside genes encoding ribosomal and mitochondrial respiratory transport chain proteins. Cell adhesion protein transcripts including type 4 collagen subunits were downregulated. Conclusions: This comparative transcriptomic dataset highlights novel and previously recognized pathogenic pathways in PEX and provides the first comprehensive transcriptomic resource, adding an additional layer to build further understanding of PEX pathophysiology.

The APOE E4 Allele Is Associated with Faster Rates of Neuroretinal Thinning in a Prospective Cohort Study of Suspect and Early Glaucoma.

Purpose: To investigate the association between the apolipoprotein E (APOE) E4 dementia-risk allele and prospective longitudinal retinal thinning in a cohort study of suspect and early manifest glaucoma. Design: Retrospective analysis of prospective cohort data. Participants: This study included all available eyes from participants recruited to the Progression Risk of Glaucoma: Relevant SNPs [single nucleotide polymorphisms] with Significant Association (PROGRESSA) study with genotyping data from which APOE genotypes could be determined. Methods: Apolipoprotein E alleles and genotypes were determined in PROGRESSA, and their distributions were compared with an age-matched and ancestrally matched normative cohort, the Blue Mountains Eye Study. Structural parameters of neuroretinal atrophy measured using spectral-domain OCT were compared within the PROGRESSA cohort on the basis of APOE E4 allele status. Main Outcome Measures: Longitudinal rates of thinning in the macular ganglion cell-inner plexiform layer (mGCIPL) complex and the peripapillary retinal nerve fiber layer (pRNFL). Results: Rates of mGCIPL complex thinning were faster in participants harboring ≥1 copies of the APOE E4 allele (ß = -0.13 µm/year; P ≤0.001). This finding was strongest in eyes affected by normal-tension glaucoma (NTG; ß = -0.20 µm/year; P = 0.003). Apolipoprotein E E4 allele carriers were also more likely to be lost to follow-up (P = 0.01) and to demonstrate a thinner average mGCIPL complex (70.9 µm vs. 71.9 µm; P = 0.011) and pRNFL (77.6 µm vs. 79.2 µm; P = 0.045) after a minimum of 3 years of monitoring. Conclusions: The APOE E4 allele was associated with faster rates of mCGIPL complex thinning, particularly in eyes with NTG. These results suggest that the APOE E4 allele may be a risk factor for retinal ganglion cell degeneration in glaucoma.

Matrix metalloproteinase-9 genetic variation and primary angle closure glaucoma in a Caucasian population.

PURPOSE: To investigate the association between genetic variation at the matrix metalloproteinase-9 (MMP9) locus and primary angle closure glaucoma (PACG) in an Australian Caucasian population. METHODS: A total of 107 Australian patients with PACG and 288 age and sex-matched controls were included in the current study. Tag single nucleotide polymorphisms (SNPs) were selected and genotyped to cover the majority of common variation within MMP9. Allele, genotype and haplotype association analyses were conducted using PLINK. RESULTS: Two SNPs from MMP9, rs3918249 and rs17576 were significantly associated under the allelic model with p values of 0.006 for both SNPs. In addition, haplotype analysis revealed a protective haplotype TACGG to be significantly more frequent in controls (69%) than in PACG cases (59%), with p=0.006. CONCLUSIONS: This study demonstrates an association between MMP9 SNPs rs3918249 and rs17576 and PACG in the Australian population, suggesting MMP9 may be involved in the pathogenesis of this blinding disease. Further replication will be helpful in confirming this finding before future clinical translation.

Towards personalized care: Factors associated with the quality of life of residents with dementia in Australian rural aged care homes.

Quality of dementia care improves with a personalized approach to aged care, and knowledge of the disease process and unique care needs of residents with dementia. A personalized model of care can have a significant impact on the overall organizational culture in aged care homes. However, the dimensions of personalized aged care relating to dementia often remain under-managed. We aim to explore the factors that shape the dimensions of personalized dementia care in rural nursing homes using qualitative data of a mixed-method 'Harmony in the Bush' dementia study. The study participants included clinical managers, registered nurses, enrolled nurses and care workers from five rural aged care homes in Queensland and South Australia. One hundred and four staff participated in 65 semi-structured interviews and 20 focus groups at three phases: post-intervention, one-month follow-up and three-months follow-up. A multidimensional model of nursing home care quality developed by Rantz et al. (1998) was used in data coding and analysis of the factors. Three key themes including seven dimensions emerged from the findings: resident and family [resident and family centeredness, and assessment and care planning]; staff [staff education and training, staff-resident interaction and work-life balance]; and organization [leadership and organizational culture, and physical environment and safety]. A lack of consideration of family members views by management and staff, together with poorly integrated, holistic care plan, limited resources and absence of ongoing education for staff, resulted in an ineffective implementation of personalized dementia care. Understanding the dimensions and associated factors may assist in interpreting the multidimensional aspects of personalized approach in dementia care. Staff training on person-centered approach, assessment and plan, and building relationships among and between staff and residents are essential to improve the quality of care residents receive.

TGC repeat expansion in the TCF4 gene increases the risk of Fuchs' endothelial corneal dystrophy in Australian cases.

Fuchs' endothelial corneal dystrophy (FECD) is a progressive, vision impairing disease. Common single nucleotide polymorphisms (SNPs) and a trinucleotide repeat polymorphism, thymine-guanine-cytosine (TGC), in the TCF4 gene have been associated with the risk of FECD in some populations. We previously reported association of SNPs in TCF4 with FECD risk in the Australian population. The aim of this study was to determine whether TGC repeat polymorphism in TCF4 is associated with FECD in the Australian population. In 189 unrelated Australian cases with advanced late-onset FECD and 183 matched controls, the TGC repeat polymorphism located in intron 3 of TCF4 was genotyped using a short tandem repeat (STR) assay. The repeat length was verified by direct sequencing in selected homozygous carriers. We found significant association between the expanded TGC repeat (≥ 40 repeats) in TCF4 and advanced FECD (P = 2.58 × 10-22; OR = 15.66 (95% CI: 7.79-31.49)). Genotypic analysis showed that 51% of cases (97) compared to 5% of controls (9) were heterozygous or homozygous for the expanded repeat allele. Furthermore, the repeat expansion showed stronger association than the most significantly associated SNP, rs613872, in TCF4, with the disease in the Australian cohort. This and haplotype analysis of both the polymorphisms suggest that considering both the polymorphisms together rather than either of the two alone would better predict susceptibility to FECD in the Australian population. This is the first study to report association of the TGC trinucleotide repeat expansion in TCF4 with advanced FECD in the Australian population.

Genome-wide association study identifies three novel loci in Fuchs endothelial corneal dystrophy.

The structure of the cornea is vital to its transparency, and dystrophies that disrupt corneal organization are highly heritable. To understand the genetic aetiology of Fuchs endothelial corneal dystrophy (FECD), the most prevalent corneal disorder requiring transplantation, we conducted a genome-wide association study (GWAS) on 1,404 FECD cases and 2,564 controls of European ancestry, followed by replication and meta-analysis, for a total of 2,075 cases and 3,342 controls. We identify three novel loci meeting genome-wide significance (P<5 × 10-8): KANK4 rs79742895, LAMC1 rs3768617 and LINC00970/ATP1B1 rs1200114. We also observe an overwhelming effect of the established TCF4 locus. Interestingly, we detect differential sex-specific association at LAMC1, with greater risk in women, and TCF4, with greater risk in men. Combining GWAS results with biological evidence we expand the knowledge of common FECD loci from one to four, and provide a deeper understanding of the underlying pathogenic basis of FECD.

Association of TCF4 and CLU polymorphisms with Fuchs' endothelial dystrophy and implication of CLU and TGFBI proteins in the disease process.

Fuchs' endothelial dystrophy (FED) is a disease affecting the corneal endothelium. Recent studies reported significant association of polymorphisms in the TCF4 (transcription factor 4) gene, and a borderline association of PTPRG (protein tyrosine phosphatase, receptor type, G) variants with late-onset FED in Caucasians from the United States. Association of TCF4 has also been reported in the Chinese population. We aimed to determine association of the reported polymorphisms in TCF4 and PTPRG, and association of polymorphisms in the candidate genes ZEB1 (zinc-finger E-box binding homoebox 1), COL8A2 (collagen, type VIII, alpha 2), TGFBI (transforming growth factor, ß-induced) and CLU (clusterin) in Australian cases. We also compared the expression of TGFBI and CLU proteins between FED and normal whole corneas. In all, 30 single-nucleotide polymorphisms (SNPs) from the candidate genes were genotyped in 103 cases and 275 controls. Each SNP and haplotype was assessed for association with the disease. SNP analysis identified an association of TCF4 (rs613872 (P=5.25 × 10(-15), OR=4.05), rs9954153 (P=3.37 × 10(-7), OR=2.58), rs2286812 (P=4.23 × 10(-6), OR=2.55) and rs17595731 (P=3.57 × 10(-5), OR=3.79)), CLU (rs17466684; P=0.003, OR=1.85) and one haplotype of TGFBI SNPs (P=0.011, OR=2.29) with FED in Caucasian Australians. No evidence for genetic association of PTPRG, ZEB1 and COL8A2 was found. Immunohistochemistry showed differential expression of CLU and TGFBI proteins in FED-affected compared with normal corneas. In conclusion, variation in TCF4, CLU and TGFBI, but not PTPRG, ZEB1 and COL8A2 genes are associated with FED in Caucasian Australian cases. Differential expression of CLU and TGFBI proteins in FED-affected corneas provides novel insights into the disease mechanism.

Sequence variation in DDAH1 and DDAH2 genes is strongly and additively associated with serum ADMA concentrations in individuals with type 2 diabetes.

BACKGROUND: Asymmetric dimethylarginine (ADMA), present in human serum, is an endogenous inhibitor of nitric oxide synthase and contributes to vascular disease. Dimethylarginine dimethylaminohydrolase (DDAH) is an ADMA degrading enzyme that has two isoforms: DDAHI and DDAHII. We sought to determine whether serum ADMA levels in type 2 diabetes are influenced by common polymorphisms in the DDAH1 and DDAH2 genes. METHODOLOGY/PRINCIPAL FINDINGS: Relevant clinical parameters were measured and peripheral whole blood obtained for serum and genetic analysis on 343 participants with type 2 diabetes. Serum ADMA concentrations were determined by mass spectroscopy. Twenty six tag SNPs in the DDAH1 and 10 in the DDAH2 gene were genotyped in all subjects and tested for association with serum ADMA levels. Several SNPs and haplotypes in the DDAH genes were strongly associated with ADMA levels. Most significantly in the DDAH1 gene, rs669173 (p = 2.96x10(-7)), rs7521189 (p = 6.40x10(-7)), rs2474123 (p = 0.00082) and rs13373844 (p = 0.00027), and in the DDAH2 gene, rs3131383 (p = 0.0029) and the TGCCCAGGAG haplotype (p = 0.0012) were significantly associated with ADMA levels. Sub-analysis by diabetic retinopathy (DR) status revealed these variants were associated with ADMA levels predominantly in participants without DR. Combined analysis of the most strongly associated SNPs in DDAH1 (rs669173) and DDAH2 (rs3131383) revealed an additive effect (p = 1.37x10(-8)) on ADMA levels. CONCLUSIONS/SIGNIFICANCE: Genetic variation in the DDAH1 and 2 genes is significantly associated with serum ADMA levels. Further studies are required to determine the pathophysiological significance of elevated serum ADMA in type 2 diabetes and to better understand how DDAH gene variation influences ADMA levels.

Diabetic retinopathy is associated with elevated serum asymmetric and symmetric dimethylarginines.

OBJECTIVE: Asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), and l-arginine directly influence nitric oxide production. Our objective was to test whether serum ADMA, SDMA, or l-arginine levels correlate with diabetic retinopathy subtype or severity. RESEARCH DESIGN AND METHODS: A total of 162 subjects with type 1 diabetes and 343 with type 2 diabetes, of whom 329 subjects had no diabetic retinopathy, 27 had nonproliferative diabetic retinopathy (NPDR), 101 had proliferative diabetic retinopathy (PDR), and 107 had clinically significant macular edema (CSME), were recruited. Blinding diabetic retinopathy was defined as severe NPDR, PDR, or CSME. Serum ADMA, SDMA, and l-arginine concentrations were determined by mass spectroscopy. RESULTS: In multivariate analysis, blinding diabetic retinopathy, PDR, and nephropathy were associated with significantly increased serum levels of ADMA (P < 0.001), SDMA (P < 0.001), and l-arginine (P = 0.001). Elevated ADMA (P < 0.001) and SDMA (P < 0.001) were also significantly associated with CSME. CONCLUSIONS: Severe forms of diabetic retinopathy are associated with elevated serum ADMA, SDMA, and l-arginine. Further investigation is required to determine whether these findings are of clinical relevance.