Effects of Green Tea Extract (GTE) on Systemic Oxidative and Antioxidative Status in Chinese Patients With Stable Asthma
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 30
- 试验地点
- 2
- 主要终点
- Serum Inflammatory markers
研究概览
简要总结
Asthma is a disease characterized by chronic inflammation in the airways. Recent research has demonstrated that one of the reasons for the chronic inflammatory state is an imbalance between oxidative stress and antioxidative defenses in patients with asthma.
Green tea is a common beverage consumed by Chinese patients from all walks of life. Green tea contains chemical components that are thought to have immunomodulatory actions in chronic inflammation.
The investigators propose to recruit 35 patients with stable asthma. Recruited subject will be given oral tablets containing Green tea extract (GTE) to be taken daily for three months. Clinical follow up and assessment will be done at baseline, on completion of GTE intake at three months, and at three months after GTE intake has been stopped. A questionnaire on their health status and the frequency of symptoms and use of bronchodilators and inhaled steroids will be completed, spirometry will be done and a venous blood sample will be taken during recruitment and during each reassessment at 3 and 6 months. Measurement of oxidants/antioxidants (GSH, GSSG, SOD, CAT and GPx) will be carried out on the blood samples. Oxidants/antioxidants will be compared and correlated with lung function results.
This study would provide us with pilot data as to whether GTE, a strong antioxidant with immunomodulatory actions, has any effect on reducing the oxidative stress and improving the antioxidant status in patients with asthma and whether these changes are accompanied improvement in clinical status.
Hypothesis Green tea extract (GTE) reduces oxidative stress and improves antioxidant defenses in Chinese patients with asthma
详细描述
- Background
Asthma constitutes a significant health problem both in Hong Kong and worldwide (1). Different risk factors for asthma have been identified. These include atopy (2), family history of asthma, exposure to indoor aeroallergens (3) air pollution (4) and exposure to environmental tobacco smoke (5).
Asthma is associated with a chronic inflammatory state in the airway. The inflammatory component is thought to result from an imbalance between an increased free radical formation (oxidative stress) and a reduction of antioxidative defenses. Reactive oxygen species (ROS) such as superoxide radicals and hydrogen peroxide were found to be increased in patients with asthma indicating the presence of oxidative stress, and the increased level of ROS has also been found to correlate with asthma severity (6).
The airway displays a wide range of enzymatic and non-enzymatic antioxidant defenses, including reduced glutathione (GSH), superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx). There is evidence of reduced antioxidant defenses, namely GPx and SOD activity, in asthma patients (6). Furthermore, the measurement of the oxidized form of glutathione, (glutathione disulfide, GSSG) could be used as an index to reflect the degree of oxidative stress in asthma and the level of GSSG has been reported to be high in the bronchial washings of asthma patients (7). We have reported that patients with asthma showed significantly increased erythrocyte GSSG, SOD and catalase activities with concomitant reduction of erythrocyte GPx (8). These results indicate a state of increased oxidative stress accompanied by an altered state of systemic antioxidant status in asthma patients.
Green tea represents one of the common beverages consumed by people from all walks of life. Epigallocatechin gallate (EGCG) is the major polyphenol (catechin) in green tea. Green tea extract (GTE) demonstrates anti-inflammatory and immunomodulatory activities. GTE has been shown to damp down neutrophil chemotaxis and attenuates interleukin-mediated inflammatory reaction cascades (9). It has also been shown to attenuate lung injury in experimental mouse model (10).
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Prevention
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 70 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Asthma patients being followed up in out-patient clinic with stable clinical condition.
- •Age 18 - 70 years
排除标准
- •Patients with known significant concomitant illness including pulmonary causes (COPD, pulmonary tuberculosis, lung cancer, bronchiectasis, interstitial lung disease and obstructive sleep apnoea) and non-pulmonary causes (hypertension, diabetes mellitus, ischaemic heart disease, stroke, cancer of other organ sites).
- •Patients with unstable asthma
- •Patients with alcohol dependence
- •Patients with abnormal liver function or is a hepatitis B or C carrier,
- •Patients who have habits of taking tea or tea extract, or under other clinical drug trial or herbs
- •Patients who are pregnant or breast feeding
- •Patients who are unwilling to participate or unable to give written consent on his/her own
结局指标
主要结局
Serum Inflammatory markers
时间窗: Six months
Serum catalase, superoxide dismutase, glutathione peroxidase, oxidized glutathione and other inflammatory markers including CRP, IL6 and IL8
次要结局
- Respiratory symptoms(Six months)