Effect of Flavanol-rich Cocoa on Peripheral and Cerebral Blood Flow in Type 2 Diabetes
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 18
- 试验地点
- 2
- 主要终点
- Change in Fasting Brain Blood Flow
研究概览
简要总结
Cocoa flavanols form part of the family of chemicals (also found in red wine and tea) which have aroused interest due to population studies suggesting that diets high in these substances might reduce risks of heart disease. In the laboratory, these flavanols have been shown to cause blood vessels to widen and blood flow to increase. As dysfunction in this ability of blood vessels to widen is now thought to play a central role in the complications of diabetes, novel ways to mitigate this are constantly being sought.
The present study aims to use non-invasive magnetic resonance imaging (MRI) to measure foot and brain blood flow before and after 7 days consumption of a cocoa drink high in flavanols, in subjects with diabetes, with and without peripheral neuropathy.
详细描述
Cocoa flavanols form part of the family of polyphenols (also found in red wine and tea) which have aroused interest due to epidemiological studies suggesting that diets high in these substances might reduce risks of heart disease. However, it is difficult to account for all sources of polyphenols in these epidemiological studies, and the level of cocoa product consumption was generally not well documented. Furthermore, in readily available cocoa products, processing may remove most of the flavanols, leading to such products varying considerably in flavanol content. Recently, laboratory studies of the effects of cocoa flavanols have suggested an effect on the relaxation of smooth muscle in blood vessel walls, specifically the element mediated by the endothelium (blood vessel wall). Studies using ultrasound methods in healthy volunteers have shown an increase in blood flow in the arm following temporary arterial occlusion.
As endothelial dysfunction is now thought to play a central role in the complications of diabetes, novel ways to mitigate this are constantly being sought. It is well recognised that diabetic peripheral nerve damage leads to abnormal foot blood flow, including impaired superficial skin blood flow, and that this is one of the factors delaying wound healing in diabetic foot ulcers (the single largest cost in secondary care diabetes).
Several techniques are currently used to monitor blood flow to the limbs, including venous occlusion plethysmography (VOP), laser Doppler methods and nuclear medicine techniques. These techniques have low spatial resolution, low specificity, are labour intensive, or require the use of injected radioactive contrast agents (which pose a particular risk to diabetic patients). Radiation dose also limits repeat studies.
The arterial spin labelling magnetic resonance (ASL MR) technique is non-invasive, but yields a quantifiable measure of blood flow with high resolution, and allows measurements to be repeated several times, as the technique uses no external contrast agents.
The present study aims to use non-invasive magnetic resonance imaging (MRI) to measure peripheral (foot) and brain blood flow at baseline and in response to a cocoa drink high in flavanols, in subjects with type 2 diabetes, with and without peripheral neuropathy.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
入排标准
- 年龄范围
- 35 Years 至 70 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Type 2 diabetes
- •Peripheral neuropathy or free from neuropathy
排除标准
- •Current foot ulceration
- •Hypertension
- •Anti-hypertensive medications other than thiazide diuretics and ACE inhibitors
- •Ischaemic heart disease
- •Peripheral vascular disease (ABPI ,0.9 &/or impalpable foot pulses)
- •Chronic kidney disease
- •Poor glycaemic control
- •Pregnancy
- •Contraindications to MRI
- •Intolerance to lactose or cow's milk protein
结局指标
主要结局
Change in Fasting Brain Blood Flow
时间窗: Day 0 and after 7d consumption of a cocoa drink
Measured by ASL-MR at Day 0 and after 7d consumption of a cocoa drink to detect a change following intervention
次要结局
- Change in Brain blood flow after acute consumption of cocoa(1,3,5 and 8hrs after cocoa consumption)
- Change in Fasting foot blood flow(Day 0 and after 7d consumption of a cocoa drink)
- Change in Foot blood flow after acute consumption of cocoa(1,3,5 and 8hrs after cocoa consumption)
- Change in Blood Flavanol concentration(Day 0 and after 7d consumption of a cocoa drink)
- Change in Fasting oxidative stress status(Day 0 and after 7 days of consuming a cocoa drink)
- Change in diabetes control(Day 0 and after 7days of consuming a cocoa drink daily)