Thiamine (vitamin B1) improves endothelium-dependent vasodilatation in the presence of hyperglycemia
Thiamine (vitamin B1) improves endothelium-dependent vasodilatation in the presence of hyperglycemia
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DOI：
10.1007/s10016-006-9055-6
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发表时间：
2006-09-01
影响因子：
1.5
通讯作者：
Sidawy, Anton N.
中科院分区：
文献类型：
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作者：
Arora, Subodh;Lidor, Anne;Sidawy, Anton N.
臂动脉血管活性(BAVA)是一种可靠的、无创性的在体评估内皮依赖性血管扩张(EDV)的方法。急性高血糖、糖耐量受损(IGT)和糖尿病会损害EDV，而EDV是动脉粥样硬化的先兆。硫胺素是细胞内葡萄糖代谢的重要辅酶。本研究的目的是评价硫胺素在高血糖状态下对BAVA的影响。研究对象包括10例健康受试者(H组，平均年龄27岁)、10例世界卫生组织糖耐量低减患者(IGT组，平均年龄65岁)和10例非胰岛素依赖型糖尿病(NIDDM组，平均年龄50岁)。采用双功能超声检测止血带阻断5min后反应性充血时的肱动脉血流变化。这项测试是在禁食10小时后，在口服75g葡萄糖后30、60和120分钟进行的，同时测量血糖水平(BGL)。一周后，在静脉注射硫胺素100 mg后，再次进行BAVA评估。比较使用硫胺素和不使用硫胺素时BGL峰值和谷底的BAVA(血流增加百分比)。糖耐量低减(P<；152.8)组由57.6%+/-12.6%改善至139.7+/-12.4%，非胰岛素依赖型糖尿病(P<；167.8)组由57.8%+/-8.3%改善至167.8+/-11.6%(P<；0.005)。另一方面，在低谷血糖水平下，H组(前硫胺素83.8+/-6.5%比后硫胺素83.8+/-17.0%，p>；0.05)和糖耐量低组(前硫胺素96.7+/-8.5%比后硫胺素104.0+/-17.4%，p>；0.05)基本保持不变。低谷血糖140 mg/dL继发的NIDDM组未测到低谷血糖时的BAVA。在健康受试者以及IGT和NIDDM患者存在高血糖的情况下，硫胺素可以改善EDV。硫胺素改善EDV的机制不是由于降糖作用，因为硫胺素在正常血糖条件下对EDV没有影响。常规应用硫胺素可能会改善内皮功能，从而减缓动脉粥样硬化的发生和发展，特别是在IGT和NIDDM患者中，这些患者容易发生加速的动脉粥样硬化。
Brachial artery vasoactivity (BAVA) is a reliable, noninvasive method of assessing endothelium-dependent vasodilatation (EDV) in vivo. Acute hyperglycemia, impaired glucose tolerance (IGT), and diabetes mellitus impair EDV, a precursor to atherosclerosis. Thiamine is a coenzyme important in intracellular glucose metabolism. The purpose of this study was to evaluate the effect of thiamine on BAVA in the presence of hyperglycemia. Ten healthy subjects (group H, mean age 27 years), 10 patients with impaired glucose tolerance by World Health Organization criteria (group IGT, mean age 65 years), and 10 patients with non-insulin-dependent diabetes mellitus (group NIDDM, mean age 50 years) were studied. Duplex ultrasound was used to measure brachial artery flow changes in response to reactive hyperemia following brachial artery tourniquet occlusion for 5 min. This test was performed after a 10 hr fast and at 30, 60, and 120 min after a 75 g oral glucose challenge along with measurements of blood glucose level (BGL). A week later, BAVA evaluation was repeated after administration of 100 mg of intravenous thiamine. BAVA (% increased blood flow) at peak and trough BGL was compared with and without thiamine. BAVA at peak glucose improved from 69.0 +/- 6.4% to 152.8 +/- 22.9% in group H (p < 0.005), from 57.6 +/- 12.6% to 139.7 +/- 12.4% in group IGT (p < 0.005), and from 57.8 +/- 8.3% to 167.8 +/- 11.6% in group NIDDM (p < 0.005) following administration of thiamine. On the other hand, at trough glucose levels, BAVA remained essentially unchanged in group H (prethiamine 83.8 +/- 6.5% vs. post-thiamine 83.8 +/- 17.0%, p > 0.05) as well as group IGT (prethiamine 96.7 +/- 8.5% vs. post-thiamine 104.0 +/- 17.4%, p > 0.05). BAVA at trough glucose was not measured in group NIDDM secondary to trough BGL > 140 mg/dL. EDV was improved by thiamine in the presence of hyperglycemia in healthy subjects and in patients with IGT and NIDDM. The mechanism by which thiamine improves EDV is not due to a glucose-lowering effect as thiamine had no effect on EDV under normoglycemic conditions. Routine administration of thiamine might improve endothelial function and therefore slow the development and progression of atherosclerosis, especially in patients with IGT and NIDDM who are prone to develop accelerated atherosclerosis.