Complement factor H polymorphism in age-related macular degeneration.

PURPOSE: To determine the association between complement factor H (CFH) polymorphism T1277C (tyrosine-402 --> histidine-402) and phenotypic variations of age-related macular degeneration (AMD). DESIGN: Cross-sectional observational study. PARTICIPANTS: Subjects with dry or wet AMD and a control population consisting of age-matched non-AMD subjects from 2 clinical facilities examined during the period January 1, 1999 through December 31, 2002. METHODS: Total DNA isolated from the leukocytes of 66 AMD subjects and 58 age-matched control subjects was studied. The CFH gene was amplified by polymerase chain reaction and analyzed by Nla III restriction fragment length analysis. MAIN OUTCOME MEASURES: Incidence of CHF polymorphism with the occurrence of AMD. RESULTS: Among the AMD patients, 15 had dry and 51 had wet AMD. For the CFH gene, the T1277C variant showed the genotype distribution as CC, TC, and TT. There was a strong association between homozygous C and AMD compared with the control population (odds ratio [OR] = 3.4; 95% confidence interval [CI], 1.32-8.74; P = 0.0053). Furthermore, dry AMD had a stronger association (OR, 8.32; 95% CI, 2.30-30.11; P = 0.001) than wet AMD (OR, 2.49; 95% CI, 0.90-6.84; P = 0.039) compared with the control population. Homozygous T was more prevalent in the control subjects compared with AMD patients (OR, 5; 95% CI, 2.18-11.43; P = 0.00005). CONCLUSIONS: Complement factor H polymorphism T1277C (tyrosine-402 --> histidine-402) is strongly associated with both dry and wet AMD and points to a possible role for inflammation in the pathogenesis of AMD.

Activation of caspase-8 and caspase-12 pathways by 7-ketocholesterol in human retinal pigment epithelial cells.

PURPOSE: To determine whether caspase or cathepsin pathways are activated in human retinal pigment epithelial cells (ARPE-19) after exposure to 7-ketocholesterol (7kCh). METHODS: ARPE-19 cells were exposed to 7kCh with or without z-VAD-fmk, a pan-caspase inhibitor. Caspase-3, -8, and -9 activities were measured by a fluorochrome inhibitor of caspase (FLICA) assay. Caspase-12 activity was detected by Western blotting. RT-PCR was performed for 18s, mortalin-2, cathepsins B, D, and L/V2. RESULTS: At 24 hours, 7kCh-treated cultures had increased caspase-8 (P < 0.001) and caspase-3 (P < 0.001) activities compared with vehicle-treated cultures. 7kCh-induced caspase-3 activation was blocked by z-VAD-fmk (P < 0.001). Caspase-9 was not activated by 7kCh treatment (P > 0.05). Procaspase-12 was cleaved into its active form after treatment with 7kCh for 24 hours. At 6 hours, the RNA level for mortalin-2, a pro-survival gene, was upregulated. ARPE-19 cells did not express RNA for cathepsins B, D, or L/V2 under any conditions. CONCLUSIONS: In ARPE-19 cells, 7kCh-induced apoptosis uses the receptor-mediated caspase-8 pathway and the endoplasmic reticulum stress-induced caspase-12 pathway but not the mitochondrial caspase-9 pathway. The cathepsin pathways are not involved in 7kCh-induced cell death. These data demonstrate that 7kCh causes a loss of cell viability through caspase-dependent apoptosis and can act as an oxidative stressor leading to retinal pigment epithelial cell atrophy. Elucidating the specific apoptotic pathways involved may have therapeutic potential for AMD and other retinal diseases.