Latvian Institute of Organic Synthesis, Aizkraukles Str. 21, Riga, LV-1006, Latvia.
Metabolism. 2014 Jan;63(1):127-36. doi: 10.1016/j.metabol.2013.09.014. Epub 2013 Oct 18.
A variety of calorie restriction diets and fasting regimens are popular among overweight people. However, starvation could result in unexpected cardiovascular effects. Therefore, it is necessary to evaluate the short-term effects of diets on cardiovascular function, energy metabolism and potential risk of heart damage in case of myocardial infarction. The objective of the present study was to investigate whether the increased level of glucose oxidation or reduction of fatty acid (FA) load in the fed state provides the basis for protection against myocardial infarction in an experimental rat model of ischemia-reperfusion.
MATERIALS/METHODS: We tested the effects of the availability of energy substrates and their metabolites on the heart functionality and energy metabolism under normoxic and ischemia-reperfusion conditions.
In a fasted state, the heart draws energy exclusively from FAs, whereas in a fed state, higher concentration of circulating insulin ensures a partial switch to glucose oxidation, while the load of FA on heart and mitochondria is reduced. Herein, we demonstrate that ischemic damage in hearts isolated from Wistar rats and diabetic Goto-Kakizaki rats is significantly lower in the fed state compared to the fasted state.
Present findings indicate that postprandial or fed-state physiology, which is characterised by insulin-activated glucose and lactate utilisation, is protective against myocardial infarction. Energy metabolism pattern in the heart is determined by insulin signalling and the availability of FAs. Overall, our study suggests that even overnight fasting could provoke and aggravate cardiovascular events and high-risk cardiovascular patients should avoid prolonged fasting periods.
各种热量限制饮食和禁食方案在超重人群中很受欢迎。然而，饥饿可能会导致意想不到的心血管效应。因此，有必要评估饮食对心血管功能、能量代谢和心肌梗死潜在风险的短期影响。本研究的目的是探讨在缺血再灌注实验大鼠模型中，进食状态下葡萄糖氧化增加或脂肪酸（FA）负荷减少是否为心肌梗死提供保护的基础。
材料/方法：我们测试了能量底物及其代谢物的可用性对正常氧合和缺血再灌注条件下心脏功能和能量代谢的影响。
在禁食状态下，心脏仅从 FAs 中获取能量，而在进食状态下，循环胰岛素浓度升高可确保部分切换到葡萄糖氧化，同时降低 FA 对心脏和线粒体的负荷。在这里，我们证明与禁食状态相比，取自 Wistar 大鼠和糖尿病 Goto-Kakizaki 大鼠的心脏在进食状态下的缺血损伤明显更低。
目前的研究结果表明，餐后或进食状态的生理学特征是胰岛素激活的葡萄糖和乳酸利用，可预防心肌梗死。心脏的能量代谢模式由胰岛素信号和 FAs 的可用性决定。总体而言，我们的研究表明，即使是 overnight fasting 也可能引发和加重心血管事件，高风险心血管患者应避免长时间禁食。
