Baumbach Philipp, Schmidt-Winter Christiane, Hoefer Jan, Derlien Steffen, Best Norman, Herbsleb Marco, Coldewey Sina M
Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Jena, Germany.
Septomics Research Center, Jena University Hospital, Jena, Germany.
Front Med (Lausanne). 2020 Dec 21;7:585462. doi: 10.3389/fmed.2020.585462. eCollection 2020.
Mitochondria are the key players in aerobic energy generation via oxidative phosphorylation. Consequently, mitochondrial function has implications on physical performance in health and disease ranging from high performance sports to critical illness. The protoporphyrin IX-triplet state lifetime technique (PpIX-TSLT) allows measurements of mitochondrial oxygen tension (mitoPO). Hitherto, few data exist on the relation of mitochondrial oxygen metabolism and ergospirometry-derived variables during physical performance. This study investigates the association of mitochondrial oxygen metabolism with gas exchange and blood gas analysis variables assessed during cardiopulmonary exercise testing (CPET) in aerobic and anaerobic metabolic phases. Seventeen volunteers underwent an exhaustive CPET (graded multistage protocol, 50 W/5 min increase), of which 14 were included in the analysis. At baseline and for every load level PpIX-TSLT-derived mitoPO measurements were performed every 10 s with 1 intermediate dynamic measurement to obtain mitochondrial oxygen consumption and delivery (mito O, mito O). In addition, variables of gas exchange and capillary blood gas analyses were obtained to determine ventilatory and lactate thresholds (VT, LT). Metabolic phases were defined in relation to VT1 and VT2 (aerobic: <VT1, aerobic-anaerobic transition: ≥VT1 and <VT2 and anaerobic: ≥VT2). We used linear mixed models to compare variables of PpIX-TSLT between metabolic phases and to analyze their associations with variables of gas exchange and capillary blood gas analyses. MitoPO increased from the aerobic to the aerobic-anaerobic phase followed by a subsequent decline. A mitoPO peak, termed mitochondrial threshold (MT), was observed in most subjects close to LT2. Mito O increased during CPET, while no changes in mito O were observed. MitoPO was negatively associated with partial pressure of end-tidal oxygen and capillary partial pressure of oxygen and positively associated with partial pressure of end-tidal carbon dioxide and capillary partial pressure of carbon dioxide. Mito O was associated with cardiovascular variables. We found no consistent association for mito O. Our results indicate an association between pulmonary respiration and cutaneous mitoPO during physical exercise. The observed mitochondrial threshold, coinciding with the metabolic transition from an aerobic to an anaerobic state, might be of importance in critical care as well as in sports medicine.
线粒体是通过氧化磷酸化进行有氧能量生成的关键参与者。因此，线粒体功能对从高性能运动到危重病等健康和疾病状态下的身体表现都有影响。原卟啉IX三线态寿命技术（PpIX-TSLT）可用于测量线粒体氧张力（mitoPO）。迄今为止，关于身体运动过程中线粒体氧代谢与运动肺功能测试衍生变量之间关系的数据很少。本研究调查了有氧和无氧代谢阶段心肺运动测试（CPET）期间评估的线粒体氧代谢与气体交换及血气分析变量之间的关联。17名志愿者进行了力竭性CPET（分级多阶段方案，每5分钟增加50W），其中14名纳入分析。在基线和每个负荷水平，每10秒进行一次PpIX-TSLT衍生的mitoPO测量，并进行1次中间动态测量，以获取线粒体氧消耗和输送（mito O，mito O）。此外，获取气体交换和毛细血管血气分析变量以确定通气阈值和乳酸阈值（VT，LT）。根据VT1和VT2定义代谢阶段（有氧：<VT1，有氧-无氧过渡：≥VT1且<VT2，无氧：≥VT2）。我们使用线性混合模型比较代谢阶段之间PpIX-TSLT的变量，并分析它们与气体交换和毛细血管血气分析变量的关联。mitoPO从有氧阶段到有氧-无氧阶段增加，随后下降。在大多数接近LT2的受试者中观察到一个mitoPO峰值，称为线粒体阈值（MT）。CPET期间mito O增加，而mito O未观察到变化。mitoPO与呼气末氧分压和毛细血管氧分压呈负相关，与呼气末二氧化碳分压和毛细血管二氧化碳分压呈正相关。mito O与心血管变量相关。我们未发现mito O有一致的关联。我们的结果表明体育锻炼期间肺呼吸与皮肤mitoPO之间存在关联。观察到的线粒体阈值与从有氧状态到无氧状态的代谢转变一致，这在重症监护以及运动医学中可能具有重要意义。
