Jevtovic Filip, Krassovskaia Polina M, Lopez Christian A, Fisher-Wellman Kelsey H, Cortright Ronald N, Broskey Nicholas T
Human Performance Laboratory, Department of Kinesiology, East Carolina University, Greenville, NC 27858, USA.
East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27858, USA.
Biomedicines. 2022 Jun 20;10(6):1456. doi: 10.3390/biomedicines10061456.
African Americans (AA) are disproportionately burdened by metabolic diseases. While largely unexplored between Caucasian (C) and AA, differences in mitochondrial bioenergetics may provide crucial insight to mechanisms for increased susceptibility to metabolic diseases. AA display lower total energy expenditure and resting metabolic rate compared to C, but paradoxically have a higher amount of skeletal muscle mass, suggestive of inherent energetic efficiency differences between these races. Such adaptations would increase the chances of overnutrition in AA; however, these disparities would not explain the racial difference in insulin resistance (IR) in healthy subjects. Hallmarks associated with insulin resistance (IR), such as reduced mitochondrial oxidative capacity and metabolic inflexibility are present even in healthy AA without a metabolic disease. These adaptations might be influential of mitochondrial "substrate preference" and could play a role in disproportionate IR rates among races. A higher glycolytic flux and provision of shuttles transferring electrons from cytosol to mitochondrial matrix could be a contributing factor in development of IR via heightened reactive oxygen species (ROS) production. This review highlights the above concepts and provides suggestions for future studies that could help delineate molecular premises behind potential impairments in insulin signaling and metabolic disease susceptibility in AA.
非裔美国人（AA）承受着不成比例的代谢性疾病负担。虽然白种人（C）和非裔美国人之间在很大程度上尚未得到充分研究，但线粒体生物能量学的差异可能为深入了解代谢性疾病易感性增加的机制提供关键线索。与白种人相比，非裔美国人的总能量消耗和静息代谢率较低，但矛盾的是，他们的骨骼肌质量却更高，这表明这两个种族之间存在内在的能量效率差异。这种适应性变化会增加非裔美国人营养过剩的几率；然而，这些差异并不能解释健康受试者中胰岛素抵抗（IR）的种族差异。即使在没有代谢疾病的健康非裔美国人中，也存在与胰岛素抵抗（IR）相关的特征，如线粒体氧化能力降低和代谢灵活性下降。这些适应性变化可能会影响线粒体的“底物偏好”，并可能在不同种族间胰岛素抵抗率不成比例中发挥作用。更高的糖酵解通量以及提供将电子从细胞质转移到线粒体基质的穿梭系统，可能是通过增加活性氧（ROS）生成导致胰岛素抵抗发展的一个因素。本综述强调了上述概念，并为未来的研究提供了建议，这些研究可能有助于阐明非裔美国人胰岛素信号潜在损伤和代谢疾病易感性背后的分子前提。
