Absence of altered expression of optineurin in primary open angle glaucoma patients

PURPOSE: To investigate the expression level of the optineurin gene (OPTN) in the blood of primary open angle glaucoma (POAG) patients to determine if altered expression is playing a role in primary open angle glaucoma systemically. METHODS: Patients (n=47) were eligible for inclusion if they met standard clinical criteria for POAG, including age greater than 40 years, intraocular pressure ≥21 mmHg in at least one eye before treatment, normal-appearing anterior chamber angles bilaterally on gonioscopy, and optic nerve injury characteristic of POAG. Control subjects (n=27) were recruited who were free from glaucoma by examination. DNA from patient was sequenced to look for possible mutations in the coding region of OPTN or its promoter. RNA was extracted from leukocytes of patients and controls and converted to cDNA by reverse transcriptase enzyme, and quantitative PCR was used to assess expression levels of OPTN and the β-globulin gene. The ratio of OPTN expression to β-globulin gene expression for POAG patients was compared to that of controls and to clinical characteristics of POAG patients. RESULTS: No mutation(s) were detected in any of the patients after sequencing the full OPTN gene and its promoter region. Mean OPTN (p≤0.35), and β-globulin (p≤0.48) gene expression values were statistically similar in POAG patients and controls. OPTN/β-globulin (p≤0.83) ratios were also indistinguishable between POAG patients and controls. OPTN/β-globulin ratios were not significantly associated with age, sex, or ethnicity of patients within the POAG group. Similarly, OPTN/β-globulin ratios were not significantly affected by ethnicity or clinical parameters related to POAG severity including maximum intraocular pressure, vertical cup-to-disk ratio, static perimetry mean deviation, or static perimetry pattern standard deviation. CONCLUSIONS: OPTN expression is not altered in the blood of POAG patients, suggesting that OPTN expression is not changed systemically and implying that other mechanisms are involved in POAG pathogenesis

Unaltered myocilin expression in the blood of primary open angle glaucoma patients

PURPOSE: To investigate the expression of the myocilin gene (MYOC) in the blood of primary open angle glaucoma (POAG) patients to determine if altered systemic expression is playing a role. METHODS: Patients (n=47) were eligible for inclusion if they met standard clinical criteria for POAG. Control subjects (n=27) were recruited who were free from glaucoma by examination. RNA was extracted from leukocytes of patients and controls and converted to cDNA by reverse transcriptase enzyme, and quantitative PCR was used to assess expression levels of MYOC and the house keeping gene β-globulin (HBB). The ratio of MYOC expression to HBB expression for POAG patients was compared to that of controls and to clinical characteristics of POAG patients. RESULTS: Mean gene expression values were statistically similar in POAG patients and controls for both MYOC (p≤0.55) and HBB (p≤0.48). MYOC/HBB ratios were also statistically indistinguishable between POAG patients and controls (p≤0.90). MYOC/HBB ratios were not significantly associated with age, sex, or ethnicity of patients within the POAG group. Similarly, MYOC/HBB ratios were not significantly associated with clinical parameters related to POAG severity, including maximum intraocular pressure, vertical cup-to-disk ratio, static perimetry mean deviation, or static perimetry pattern standard deviation. CONCLUSIONS: MYOC expression is not altered in the blood of POAG patients, unlike MYOC expression in trabecular meshwork (TM) cultures. These results suggests that MYOC expression is not altered systemically but rather that MYOC expression may contribute to POAG pathogenesis in specific tissues such as TM