Systemic Glutathione Level in Normal Tension Glaucoma

Evaluation of Systemic Glutathione Level in Patients With Normal Tension Glaucoma

The purpose of this study is to evaluate whether systemic glutathione level is decreased in patients with normal tension glaucoma.

Study Overview

• Status: Completed
• Conditions: Normal Tension Glaucoma

Detailed Description

Normal tension glaucoma is one of the most common cause of primary open angle glaucoma in Korea. Even though, we still do not know what the cause is. Only IOP-lowering drugs are the currently available therapeutic method. Glutathione is one of the mostly high concentrated intracellular antioxidants. We find apoptosis of neuronal cell in the mouse retina by systemic depletion of glutathione using buthionine sulfoximine. Glutathione is also known to be reduced in primary open angle glaucoma with high IOP. So we are planning to evaluate systemic glutathione level in normal tension glaucoma.

Blood samples will be obtained by venipuncture to the antecubital vein of normal tension glaucoma patients and age-matched normal controls. Five milliliters of blood will be collected in EDTA-treated tubes (to prevent oxidation). Thirty microliters of blood will be then transferred into centrifuge tubes, and will be added 33.3 microliter of 5-sulfosalicylic acid (SSA), 100mg/mL within 10 minutes from the blood collection.Each sample will be then diluted with 936.7 microliter sodium phosphate buffer (pH 7.5), and the content of each tube will be mixed rapidly in a centrifuge at 13,000 rpm for 5 minutes. A portion of supernatant (150 microliter) will be then collected into clean centrifuge tubes and immediately cooled at -70°C. To each well of a 96-well plate, 150 microliter of daily buffer (3 mg NADPH into 10 mL sodium phosphate buffer), 50microliter of DTNB solution, and 25 microliter of standards or samples will be added in quadruplicate, and the plate will be incubated at 37 °C for 3 minutes.Finally, 25 microliter GSSGR will be added to the previous mixture, and the plate will be read at 410 nm using a 96-well plate reader(UV spectrophotometer).

• Study Type: Observational
• Enrollment (Actual): 49

Contacts and Locations

Study Locations

• Korea, Republic of
  • Seoul, Korea, Republic of, 150-713
    • College of Medicine, The Catholic University of Korea, St. Mary's Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

patients of tertiary referred center

Description

Patients were included in the normal tension glaucoma group according to the following criteria.

Inclusion Criteria (normal tension glaucoma group):

• Clinical Diagnosis of Normal Tension Glaucoma: Patients underwent diurnal IOP phasing and were diagnosed as having normal tension glaucoma(IOP always lesser than 22 mm Hg by applanation tonometry), glaucomatous optic disc cupping on fundoscopic examination, open anterior chamber angles by gonioscopy(Schaffer grade III or more), and repeatable VF defects consistent with the diagnosis of glaucoma, according to results obtained with program 24-2 of the Humphrey Field Analyzer.
• Must be able to provide intravenous blood sampling

Exclusion Criteria (normal tension glaucoma group):

• Narrow iridocorneal angles
• Any evidence of secondary open-angle glaucoma
• Any other ocular disease except cataract
• History of previous intraocular surgery including cataract
• Any other systemic disease except hypertension

The control group was composed of age-matched healthy volunteers who had neither glaucoma nor other ocular diseases such as cataract, diabetic retinopathy or age related macular degeneration. The control group did not show any glaucomatous optic disc cupping on fundoscopic examination or visual field defects with program 24-2 of the Humphrey Field Analyzer. The healthy volunteers in the control group must be able to provide intravenous blood sampling.

Exclusion criteria for both groups:

• Smoking
• History of any chronic systemic disease with presumed low glutathione levels, including autoimmune diseases, alcoholic liver disease, cancer, and diabetes mellitus.

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total Glutathione Levels	Subjects were instructed to fast from midnight to 8 AM on the morning of the test. All blood samples were obtained by a qualified registered nurse in the morning, between 8 and 10 AM.	Once in the morning.

Collaborators and Investigators

• Sponsor: The Catholic University of Korea
• Investigators: Study Director: Jung-Il Moon, Professor, Department of Ophthalmology, St.Mary's Hospital, College of Medicine, The Catholic University of Korea

Study record dates

Study Major Dates

• Study Start: March 1, 2008
• Primary Completion (Actual): October 1, 2008
• Study Completion (Actual): October 1, 2008

Study Registration Dates

• First Submitted: December 7, 2007
• First Submitted That Met QC Criteria: December 7, 2007
• First Posted (Estimate): December 10, 2007

Study Record Updates

• Last Update Posted (Estimate): August 10, 2010
• Last Update Submitted That Met QC Criteria: July 14, 2010
• Last Verified: December 1, 2007

More Information

Terms related to this study

• Keywords: Glutathione; Antioxidant; Normal tension glaucoma
• Additional Relevant MeSH Terms: Eye Diseases; Ocular Hypertension; Optic Nerve Diseases; Glaucoma; Low Tension Glaucoma
• Other Study ID Numbers: Merck-001; CMCEYE-GSH