Evaluating the activity of cardiac mitochondria is probably the best way to estimate early cellular damage in chronic pathology. Early diagnosis allows rapid therapeutic intervention thus increasing patient survival rate in a number of diseases. However, data on human cardiac mitochondria are scarce in the international literature. Here, we describe a method to extract and study functional mitochondria from the small-sized right atrial aliquots (minimum of 400 mg) obtained during extracorporeal circulation and usually considered as surgical waste products. The mitochondria were purified through several mechanical processes (fine myocardial cutting, tissue grinding and potter Elvehjem homogenising), an enzymatic proteolytic action (subtilisin) and differential centrifugations. In chronic pathologies, including obesity, early disturbances of mitochondrial function can occur. The effects of obesity on the rate of mitochondrial oxygen consumption and H2O2 release were thus determined with three different substrates (glutamate/malate, succinate/rotenone and palmitoylcarnitine/malate). The human atrial mitochondria were of high quality from a functional viewpoint, compared to rat ventricle organelles, but the extraction yield of the human mitochondria was twice lower than that of rat mitochondria. Tests showed that glutamate/malate-related ADP-stimulated respiration was strongly increased in obese subjects, although the oxidation of the other two substrates was unaffected. Reactive oxygen species (ROS) production by the isolated mitochondria was low in comparison with that of the lean subjects. These results confirm those found in one of our previous studies in the ventricles of rats fed a high-fat diet. In conclusion, the described method is simple, reliable and sensitive. It allows for the description of the impact of obesity on the function of atrial mitochondria while using only a small patient sampling (n = 5 in both the lean and the obese groups).

中文翻译：

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从小型人房样本中提取功能性线粒体的程序。具有部分细胞器特征的肥胖症的应用。

评价心脏线粒体的活性可能是评估慢性病理中早期细胞损伤的最佳方法。早期诊断可以快速进行治疗干预，从而提高多种疾病的患者存活率。但是，国际文献中关于人心脏线粒体的数据很少。在这里，我们描述了一种从体外循环中获得的，通常被视为手术废物的小型右心房等分试样（最少400 mg）中提取和研究功能性线粒体的方法。线粒体通过几种机械过程（精细的心肌切割，组织研磨和波特Elvehjem匀浆），酶促蛋白水解作用（枯草杆菌蛋白酶）和差异离心来纯化。在包括肥胖在内的慢性疾病中，可能会发生线粒体功能的早期紊乱。因此，通过三种不同的底物（谷氨酸/苹果酸，琥珀酸/鱼藤酮和棕榈酰肉碱/苹果酸）确定了肥胖对线粒体耗氧率和H2O2释放速率的影响。从功能的角度来看，人心房线粒体比大鼠心室细胞器高品质，但人线粒体的提取率比大鼠线粒体低两倍。测试显示，尽管其他两种底物的氧化不受影响，但肥胖受试者中谷氨酸/苹果酸相关的ADP刺激的呼吸作用显着增加。与瘦的受试者相比，分离的线粒体产生的活性氧（ROS）较低。这些结果证实了在我们先前的一项研究中发现，在高脂饮食的大鼠心室中发现的那些结果。总之，所描述的方法简单，可靠且灵敏。它允许描述肥胖症对心房线粒体功能的影响，同时仅使用少量患者样本（瘦弱人群和肥胖人群中n = 5）。