Mitochondrial Changes in Platelets Are Not Related to Those in Skeletal Muscle during Human Septic Shock

Platelets can serve as general markers of mitochondrial (dys)function during several human diseases. Whether this holds true even during sepsis is unknown. Using spectrophotometry, we measured mitochondrial respiratory chain biochemistry in platelets and triceps brachii muscle of thirty patients with septic shock (within 24 hours from admission to Intensive Care) and ten surgical controls (during surgery). Results were expressed relative to citrate synthase (CS) activity, a marker of mitochondrial density. Patients with septic shock had lower nicotinamide adenine dinucleotide dehydrogenase (NADH)/CS (p = 0.015), complex I/CS (p = 0.018), complex I and III/CS (p<0.001) and complex IV/CS (p = 0.012) activities in platelets but higher complex I/CS activity (p = 0.021) in triceps brachii muscle than controls. Overall, NADH/CS (r2 = 0.00; p = 0.683) complex I/CS (r2 = 0.05; p = 0.173), complex I and III/CS (r2 = 0.01; p = 0.485), succinate dehydrogenase (SDH)/CS (r2 = 0.00; p = 0.884), complex II and III/CS (r2 = 0.00; p = 0.927) and complex IV/CS (r2 = 0.00; p = 0.906) activities in platelets were not associated with those in triceps brachii muscle. In conclusion, several respiratory chain enzymes were variably inhibited in platelets, but not in triceps brachii muscle, of patients with septic shock. Sepsis-induced mitochondrial changes in platelets do not reflect those in other organs.

在多种人类疾病进程中，血小板可作为线粒体功能（失调）的通用生物标志物。但该关联在脓毒症中是否成立仍未明确。本研究采用分光光度法，对30例脓毒性休克患者（入院重症监护室24小时内）及10例手术对照患者（手术期间）的血小板与肱三头肌组织进行线粒体呼吸链生化指标检测。检测结果以柠檬酸合酶（citrate synthase, CS）活性作为归一化参照，该酶为线粒体密度标志物。与对照组相比，脓毒性休克患者的血小板中烟酰胺腺嘌呤二核苷酸脱氢酶（nicotinamide adenine dinucleotide dehydrogenase, NADH）/CS（p=0.015）、复合物I/CS（p=0.018）、复合物I+III/CS（p<0.001）及复合物IV/CS（p=0.012）活性均显著降低，但其肱三头肌组织中复合物I/CS活性（p=0.021）则显著升高。整体而言，血小板中的NADH/CS（r²=0.00；p=0.683）、复合物I/CS（r²=0.05；p=0.173）、复合物I+III/CS（r²=0.01；p=0.485）、琥珀酸脱氢酶（succinate dehydrogenase, SDH）/CS（r²=0.00；p=0.884）、复合物II+III/CS（r²=0.00；p=0.927）及复合物IV/CS（r²=0.00；p=0.906）活性，均与肱三头肌组织中的对应活性无显著相关性。综上，脓毒性休克患者的血小板中存在多种呼吸链酶活性受抑的情况，但肱三头肌组织中并无此现象；脓毒症诱导的血小板线粒体变化，并不能反映其他器官的线粒体改变。