高血糖会导致心脏病发作并发症

High blood sugar levels could lead to heart attack complications

　

　

日期: 2016年1月5日

来源: 莱斯特大学

　

　

研究人员报告说，葡萄糖(糖)导致血管收缩的直接证据首次被证实。即使是在一顿大餐后达到的血糖水平，也足以产生这种效果。这项研究为心脏病发作或中风后改善预后提供了一个潜在的治疗目标。

 

莱斯特大学的科学家首次展示了血糖水平对血管收缩的影响机制，对心脏和血压有潜在的危险影响。

 

由来自大学心血管科学部门的理查德·彩虹博士领导的研究人员已经表明，高血糖时血管收缩比正常生理水平时更强。

 

血管的收缩和舒张控制血压。一般来说，血管收缩越强，血压越高。利用电生理学和肌电图技术来检查葡萄糖对动脉肌细胞的影响，这些细胞构成了我们血管的组织，研究小组已经确定了一种控制血管收缩的机制。

 

　

当给心肌供血以提供所需的营养和氧气的冠状动脉阻塞时，就会发生心肌梗塞。心脏病发作时的高血糖会使血管阻塞加重，从而导致更严重的并发症风险。

 

心血管细胞生理学讲师理查德·虹博士说:“我们已经证明，血液中糖或葡萄糖的含量会改变血管的行为，使它们比正常情况下更容易收缩。”这可能导致血压升高，或者减少重要器官的血液灌注量。

 

这是一项实验性的实验室研究，这意味着我们可以在受控的环境中得出因果关系的结论。在这里，我们发现了一个已知的信号蛋白家族，蛋白激酶C，是增强收缩反应的一个关键部分，并且在我们的实验中也表明，使用这些蛋白质的抑制剂，我们可以恢复正常水平的收缩反应，并逆转对心脏的影响。

 

这是第一个直接证明葡萄糖使血管收缩，以及这个收缩反应背后的潜在机制的研究。我们在本研究中使用的实验模型，包括人类血管，将葡萄糖增加到一餐大餐后就可以达到的血糖水平，就可以改变血管的收缩。

 

“很多心脏病发作的病人因为‘压力反应’而有高血糖。”这意味着即使不是糖尿病患者在心脏病发作时也会变得高血糖。

　

　

 

这项研究的研究团队有研究葡萄糖对心血管系统、糖尿病和心脏功能的影响的历史。早在2010年的一项研究表明，任何原因的高血糖，不仅仅是糖尿病，都是心脏病发作后“更糟糕的结果”的指标。2012年，莱斯特集团的进一步研究表明，葡萄糖对心脏的正常功能有潜在的破坏性影响，比如心律失常，并消除了心脏在压力下激活的内在保护性机制。

 

彩虹博士补充道:“我们的研究表明，葡萄糖对心血管系统的正常功能有重要的生理影响。血糖升高到病理生理水平会导致正常的血管和心肌的变化，如果不及时治疗可能会危及生命。

“我们的数据显示了明显的葡萄糖诱导的血管收缩增强。针对特定类型的蛋白激酶C，我们已经证明，它可以提供一种新的治疗途径来改善缺血性疾病的结果，例如心脏病发作或中风。

 

英国心脏基金会(British Heart Foundation)副医学主任杰里米·皮尔森(Jeremy Pearson)教授说:“这个研究小组已经证明，在多种物种中，可以使用PKC作为目标，阻止血液中高水平的葡萄糖引起的血管收缩。”这就为通过提高葡萄糖水平来治疗心脏病的病人提供了改善治疗的可能性。

　

 

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High blood sugar levels could lead to heart attack complications

 

Date:

January 5, 2016

Source:

University of Leicester

Summary:

Direct evidence of blood vessel contraction due to glucose (sugar) has now been demonstrated for the first time, researchers report. These effects were observed even at glucose levels that could be reached after a large meal. This research provides a potential therapeutic target for improving outcomes following a heart attack or stroke

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FULL STORY

Scientists at the University of Leicester have demonstrated for the first time the mechanism by which the level of sugar in your blood can affect the contraction of blood vessels, with potentially dangerous effects on the heart and blood pressure.

 

Researchers led by Dr Richard Rainbow from the University's Department of Cardiovascular Sciences have shown that blood vessels contract more strongly at raised glucose levels than at 'normal physiological' levels.

 

Blood vessels contract and relax to control blood pressure. In general, the more contracted the blood vessels are, the higher the blood pressure. Using electrophysiology and myography techniques to examine the impact of glucose on arterial myocytes, cells that make up the tissue of our blood vessels, the team has identified a mechanism that controls the narrowing of blood vessels.

 

The research comes as MPs and health experts debate proposals for a 'sugar tax' and highlights the potential health risks of consuming large amounts of rich, sugary foods regularly in your diet. With healthy eating among the most common New Year's resolutions, it adds another incentive to reduce our intake of these foods all year round.

 

Heart attacks occur when a coronary artery, which provides the blood to the heart muscle to give the required nutrients and oxygen, are blocked. High glucose at the time of heart attack could make this block more severe by causing the blood vessel to contract, leading to a higher risk of complications.

 

Dr Richard Rainbow, Lecturer in Cardiovascular Cell Physiology, said: "We have shown that the amount of sugar, or glucose, in the blood changes the behaviour of blood vessels making them contract more than normal. This could result in higher blood pressure, or could reduce the amount of blood that flows through vital organs.

 

"This was an experimental lab study which means that we can draw conclusions about cause and effect in a controlled environment. Here, we have identified a known signalling protein family, protein kinase C, is a key part of this enhanced contractile response, and have also shown in our experiments that we can restore the normal level of contractile response, and reverse the effects on the heart, with inhibitors of these proteins.

 

"This is the first study to show direct evidence of blood vessel contraction to glucose, and the potential mechanism behind this contractile response. In the experimental models we used in this study, including human blood vessels, increasing glucose to the levels that could be reached after a large meal altered vascular contraction.

 

"A large number of people who suffer a heart attack will have high glucose due to the 'stress response'. This means that even people who are not diabetic may become hyperglycaemic during a heart attack."

 

The research team that worked on this study has a history of investigating the effects of glucose on the cardiovascular system, diabetes and heart function. Previous research in 20101 showed that high glucose from any cause, not just diabetes, was an indicator of a 'worse outcome' following a heart attack. Further research in 20142 by the Leicester group showed that glucose has potentially damaging effects on the normal function of the heart, such as arrhythmia and abolishing the built-in protective mechanisms that the heart can activate on stress.

 

Dr Rainbow added: "Our studies show that glucose has an important physiological effect on the normal functioning of the cardiovascular system. Increases in blood sugar to pathophysiological levels cause marked changes in normal blood vessel and cardiac muscle behaviour that could be life-threatening if left untreated.

 

"Our data show a clear glucose-induced potentiation of contraction in blood vessels. Targeting the specific types of protein kinase C that we've shown to be involved in this can provide a novel therapeutic route for improving outcome in ischaemic diseases, such as heart attack or stroke."

 

Professor Jeremy Pearson, Associate Medical Director at the British Heart Foundation, said: "This team have shown that, in multiple species, it is possible to use PKC as a target to block blood vessel constriction caused by high levels of glucose in the blood. This opens up the possibility for improved treatment for patients where recovery from heart attack is complicated by raised glucose levels."

 

University of Leicester. "High blood sugar levels could lead to heart attack complications." ScienceDaily. ScienceDaily, 5 January 2016. <www.sciencedaily.com/releases/2016/01/160105101902.htm>.