Proinflammatory cytokines and angiogenic and anti-angiogenic factors in vitreous of patients with proliferative diabetic retinopathy and eales' disease.

PURPOSE: To investigate the mechanism of angiogenesis in proliferative diabetic retinopathy (PDR) and Eales' disease (ED) on the basis of the levels of proinflammatory cytokines, angiogenic growth factor, and antiangiogenic factor in the vitreous humor. METHODS: Twenty-five patients with PDR, 10 patients with ED, and 25 with macular hole (MH) as control subjects were studied. The concentration of the proinflammatory cytokines interleukin-6 (IL-6), IL-8, IL-1 beta; chemokine-monocyte chemoattractant protein-1 (MCP-1); angiogenic factor-vascular endothelial growth factor (VEGF); and antiangiogenic factor-pigment epithelium derived factor (PEDF) in the vitreous fluid obtained from the eyes during vitrectomy were measured by sandwich enzyme linked immunosorbent assay (ELISA). RESULTS: IL-6, IL-8, MCP-1, and VEGF levels in the vitreous were significantly higher in PDR (P < 0.0001) and ED (P < 0.0001) than in MH patients. Conversely, the vitreous level of PEDF was significantly reduced in PDR (P < 0.0001) but not in ED. A significant correlation was observed between VEGF and IL-6 in ED patients. CONCLUSION: The authors demonstrate the importance of VEGF in retinal neovascularization of ED which is an idiopathic inflammatory venous occlusion. Further study is required to understand the interrelationship between VEGF and inflammatory cytokines in PDR and ED.

Pegaptanib sodium for ocular vascular disease.

Pegaptanib sodium (Macugen) is a selective RNA aptamer that inhibits vascular endothelial growth factor (VEGF) 165 , the VEGF isoform primarily responsible for pathologic ocular neovascularization and vascular permeability, while sparing the physiological isoform VEGF 121 . After more than 10 years in development and preclinical study, pegaptanib was shown in clinical trials to be effective in treating choroidal neovascularization associated with age-related macular degeneration. Its excellent ocular and systemic safety profile has also been confirmed in patients receiving up to three years of therapy. Early, well-controlled studies further suggest that pegaptanib may provide therapeutic benefit for patients with diabetic macular edema, proliferative diabetic retinopathy and retinal vein occlusion. Notably, pegaptanib was the first available aptamer approved for therapeutic use in humans and the first VEGF inhibitor available for the treatment of ocular vascular diseases.

Identification of novel FZD4 mutations in Indian patients with familial exudative vitreoretinopathy.

PURPOSE: To identify novel mutations in FZD4 gene that cause familial exudative vitreoretinopathy (FEVR) in Indian patients. METHODS: The study was conducted on 75 subjects from 53 Indian families. These families were clinically diagnosed to have FEVR by fundus examination and fluorescein angiography. The candidate gene FZD4 was amplified from genomic DNA and PCR products were screened for mutations by single strand conformational polymorphism (PCR-SSCP), TA-cloning followed by bi-directional sequencing. RESULTS: For the FZD4 exonic region, three mutations were identified, including two novel sequence variations (C204R, F82fsX135) and one reported (P33S) mutation. These sequence changes were not observed in 100 normal controls and clinically unaffected family members analyzed. CONCLUSIONS: Mutations in FZD4 were observed in 5.6% of the clinically diagnosed FEVR, in the studied Indian population. The identified genetic variations of FZD4 could play a vital role in pathogenesis and provide greater insight in to the genotype/phenotypic functions of FZD4 gene.

Association of VEGF and eNOS gene polymorphisms in type 2 diabetic retinopathy.

PURPOSE: Vascular endothelial growth factor (VEGF) is a major mediator of angiogenesis, and nitric oxide (NO) is an upstream and downstream regulator of VEGF mediated angiogenesis. VEGF and NO have been suggested to play an important role in the pathogenesis of microvascular complications in diabetic retinopathy (DR). The objective of this study was to examine the genetic variations of the VEGF and eNOS gene and assess their possible relationship to DR in type 2 diabetic patients in the Indian population. METHODS: In this study, 210 unrelated patients were enrolled and categorized into two study groups: a DR group, consisting of patients with proliferative diabetic retinopathy, and a diabetic without retinopathy (DWR) group comprised of patients with type 2 diabetes of more than 15 years duration who showed no signs of DR or had fewer than five dots or blot hemorrhages. Association of the genetic polymorphisms in the promoter and 5' UTR region of VEGF and the intron4 region of eNOS were studied. Total genomic DNA was isolated from peripheral blood leukocytes. PCR-RFLP analysis was performed for all samples to evaluate the genotypes. The distributions of the genotypes were compared using the chi2 test. Haplotype estimation and multiple logistic regression analysis were carried out to analyze the significance of polymorphisms. RESULTS: We investigated four reported polymorphisms in the VEGF (5' UTR, promoter) and one reported polymorphism (intron 4) in the eNOS gene in Type 2 diabetes patients with (n=120) and without (n=90) retinopathy. The genotype distribution of the C(-7)T, T(-1498)C, and C(-634)G polymorphisms of VEGF differed significantly between patients with DR and DWR (p=0.001, p=0.0001, and p=0.021, respectively). Allele C in the -1498 region (p=0.0001) and T in -7 region (p=0.002) were also found to be significantly increased in patients with retinopathy. Calculated odds ratios (OR) for three heterozygous genotypes of C(-7)T, T(-1498)C, and C(-634)G regions were 4.17 (95% CI: 1.90-9.18, p=0.0001), 4.37 (95% CI: 2.44-7.84, p=0.0001), and 2.33 (95% CI: 1.24-4.36, p=0.008), respectively, and was found to be significantly higher in the DR group when compared with the DWR group. Multiple logistic regression analysis revealed that the nongenetic parameters, age (p=0.024) and duration of diabetes (p=0.009), and the genetic parameters, like VEGF C(-7)T (p=0.002) and T(-1498)C (p=0.001) polymorphisms, were significantly associated with DR. The frequencies of haplotype consisting of the majority of alleles in VEGF were found to be significantly associated with DR. The genotype distribution of eNOS did not differ significantly between the two study groups, and therefore the eNOS intron 4 polymorphism was considered to be less significant. CONCLUSIONS: This is the first study to report VEGF and eNOS gene polymorphisms in patients with DR in the Indian population. The data suggest that the polymorphisms in the 5' UTR and promoter region of VEGF could be regarded as a major genetic risk factor for DR.

A pilot study on awareness of diabetic retinopathy among non-medical persons in South India. The challenge for eye care programmes in the region.

This study was conducted to determine awareness and practices relating to diabetic retinopathy among non-medical persons in a south Indian population. In this population-based cross-sectional study, trained social workers conducted face-to-face interviews using a semi-structured questionnaire with 200 randomly selected paramedical personnel and 204 persons randomly selected from the community. Responses were graded on a five-point scale. Over half of respondents were not aware of risk factors for diabetic retinopathy. Only one-fifth of paramedics and one-tenth of persons from the community were aware that uncontrolled diabetes was a risk factor for retinopathy. Over 75% of respondents were not aware of either laser or surgery as an intervention for retinopathy. Although 80% of respondents from the community felt that yearly eye examinations were essential, only 43.5% had ever visited an ophthalmologist. Nearly three-fourths of paramedical personnel did not have any material related to diabetes for health education. It is evident that considerable effort is required to improve awareness of diabetic retinopathy, and to translate this improved awareness to actual utilisation of services.

Mutation analysis of congenital cataracts in Indian families: identification of SNPS and a new causative allele in CRYBB2 gene.

PURPOSE: To study some functional candidate genes in cataract families of Indian descent. METHODS: Nine Indian families, clinically documented to have congenital/childhood cataracts, were screened for mutations in candidate genes such as CRYG (A-->D), CRYBB2, and GJA8 by PCR analyses and sequencing. Genomic DNA samples of either probands or any representative affected member of each family were PCR amplified and sequenced commercially. Documentation of single nucleotide polymorphisms (SNPs) and candidate mutations was done through BLAST SEARCH (http://www.ncbi.nlm.nih.gov/blast/Blast.cgi?). RESULTS: Several single nucleotide polymorphisms in CRYG, CRYBB2, and GJA8 genes were observed. Because they do not co-segregate with the phenotype, they were excluded as candidates for the cataract formation in these patients. However, a substitution (W151C in exon 6 of CRYBB2) was identified as the most likely causative mutation underlying the phenotype of central nuclear cataract in all affected members of family C176. Protein structural interpretations demonstrated that no major structural alterations could be predicted and that even the hydrogen bonds to the neighboring Leu166 were unchanged. Surprisingly, hydropathy analysis of the mutant betaB2-crystallin featuring the amino acids at position 147 to 155, further increased the hydrophobicity, which might impair the solubility of the mutant protein. Finally, the Cys residue at position 151 might possibly be involved in intramolecular disulphide bridges with other cysteines during translation, possibly leading to dramatic structural changes. CONCLUSIONS: Exon 6 of CRYBB2 appears to be a critical region susceptible for mutations leading to lens opacity.

Developing a screening program to detect sight-threatening diabetic retinopathy in South India.

OBJECTIVE: To develop a screening protocol for detection of sight-threatening diabetic retinopathy in south India. RESEARCH DESIGN AND METHODS: We performed ophthalmic examinations, including posterior segment examination, using indirect ophthalmoscopy to detect sight-threatening retinopathy in patients with diabetes in screening camps targeting a high-risk population. RESULTS: We examined 3,949 persons with diabetes in 32 screening camps over a 13-month period beginning July 2001. Most of the patients (93.6%) were aware of their diabetic status, and 84.2% of those aware of their diabetes status were on treatment. One-fifth of those screened had evidence for any retinopathy; only 6.1% of these persons had evidence of past ophthalmic treatment for retinopathy. Only one-quarter of those diagnosed with worse than mild retinopathy came for follow-up to the base hospital within 2 months. CONCLUSIONS: Screening high-risk groups for sight-threatening retinopathy using indirect ophthalmoscopy may be a useful short-term alternative for India until retinal photography becomes affordable. In addition to strategies to improve coverage, strategies for better follow-up of subjects screened also need to be evolved.