Effects of Vitamin C on Hyperoxia-Induced Reduction of Retinal Blood Flow
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 12
- 试验地点
- 1
- 主要终点
- Intraocular pressure (applanation tonometry)
研究概览
简要总结
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Diagnostic
- 盲法
- Double (Participant, Investigator)
入排标准
- 年龄范围
- 19 Years 至 35 Years（Adult）
- 性别
- Male
- 接受健康志愿者
- 是
入选标准
- •Men aged between 19 and 35 years, nonsmokers
- •Body mass index between 15th and 85th percentile (Must A 1991)
- •Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
- •Normal laboratory values unless the investigator considers an abnormality to be clinically irrelevant
- •Normal ophthalmic findings, ametropia < 3 Dpt.
排除标准
- •Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
- •Treatment in the previous 3 weeks with any drug
- •Symptoms of a clinically relevant illness in the 3 weeks before the first study day
- •History of hypersensitivity to the trial drug or to drugs with a similar chemical structure
- •History or presence of gastrointestinal, liver or kidney disease, or other conditions known to interfere with, distribution, metabolism or excretion of study drugs
- •Blood donation during the previous 3 weeks
研究组 & 干预措施
1
vitamin C (Mayrhofer)
干预措施: vitamin C (Mayrhofer) 24mg/min i.v. for 64 min (Dietary Supplement)
1
vitamin C (Mayrhofer)
干预措施: 100% O2 (AGA) two times for 12 min (Other)
2
Placebo
干预措施: Placebo (Dietary Supplement)
2
Placebo
干预措施: 100% O2 (AGA) two times for 12 min (Other)
结局指标
主要结局
Intraocular pressure (applanation tonometry)
时间窗: in total 10 minutes
Retinal blood flow velocity (laser Doppler velocimetry)
时间窗: in total 6 hours
Retinal arterial and venous diameter (Zeiss retinal vessel analyzer)
时间窗: in total 6 hours
次要结局
未报告次要终点