NCT00712907

Effects of Vitamin C on Hyperoxia-Induced Reduction of Retinal Blood Flow

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 12 (actual)
• Sponsor: Medical University of Vienna · Academic / Other
• Sex: Male
• Age: 19 Years – 35 Years
• Healthy volunteers: Accepted

Summary

High arterial blood oxygen tension leads to vasoconstriction of retinal vessels, possibly related to an interaction between reactive oxygen species and endothelium-derived vasoactive factors. Vitamin C is a potent antioxidant capable of reversing endothelial dysfunction due to increased oxidant stress. Vitamin C appears to have vasodilatory properties, but the underlying mechanisms are not well understood. In the present study we hypothesized that hyperoxic vasoconstriction of retinal vessels could be diminished by vitamin C. Ocular blood flow will be determined by non-invasive methods, including laser Doppler velocimetry and the Zeiss retinal vessel analyser.

Conditions

• Ocular Physiology
• Regional Blood Flow

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	vitamin C (Mayrhofer) 24mg/min i.v. for 64 min	Substance: Ascorbic acid (Mayrhofer) Manufacturer: Mayrhofer, Linz, Austria Dosage form: i.v. Dosage: 24mg/min over 64 min Dosage reference: Ting HH 1996
DIETARY_SUPPLEMENT	Placebo	Substance: Physiologic saline solution 0.9% (placebo) Dosage form: i.v. Dosage: 24ml/min over 64 min
OTHER	100% O2 (AGA) two times for 12 min	Substance: 100% oxygen (AGA, Vienna, Austria, gases for human use) Manufacturer: AGA, Vienna, Austria, gases for human use Dosage form: Inhalation through an oxygenmask over a period of 12 minutes two times per study day. Dosage reference: Strenn K 1997

Timeline

• Start date: 2003-02-01
• Primary completion: 2003-05-01
• Completion: 2003-05-01
• First posted: 2008-07-10
• Last updated: 2008-07-10

Locations

1 site across 1 country: Austria