Kuppusamy Periannan
Departments of Radiology and Medicine, Geisel School of Medicine, Dartmouth College, Lebanon, NH, USA
Physiological homeostasis in aerobic organisms is strictly maintained by optimal cellular and tissue oxygen levels through intricate oxygen-sensing mechanisms, signaling cascades, and transport processes. Molecular oxygen is at the center of oxygenation, oxidative phosphorylation, and oxidative stress. An increase (hyperoxia) or decrease (hypoxia) in cellular oxygen level may result in altered cell-signaling cascades and redox imbalance leading to pathophysiological processes including cell death and tissue damage. Hypoxia has been implicated as a critical factor influencing the outcomes for several diseases, including cardiovascular diseases (myocardial infarction, ischemic stroke, and peripheral arterial disease), cancer, wound healing, and diabetic foot ulcer. The capability to measure tissue oxygenation in a reliable and repeated manner will be immensely useful for correct prognosis and treatment. This chapter focuses on the methods, particularly electron paramagnetic resonance (EPR) oximetry for quantitative measurement of tissue oxygenation using implantable oxygen sensors. Representative examples for cardiovascular and cancer applications are presented.
需氧生物体内的生理稳态通过复杂的氧传感机制、信号级联反应和运输过程，由最佳的细胞和组织氧水平严格维持。分子氧处于氧合作用、氧化磷酸化和氧化应激的核心位置。细胞氧水平的升高（高氧）或降低（低氧）可能导致细胞信号级联反应改变和氧化还原失衡，从而引发包括细胞死亡和组织损伤在内的病理生理过程。低氧被认为是影响多种疾病预后的关键因素，这些疾病包括心血管疾病（心肌梗死、缺血性中风和外周动脉疾病）、癌症、伤口愈合和糖尿病足溃疡。以可靠且可重复的方式测量组织氧合的能力对于正确的预后和治疗将极为有用。本章重点介绍相关方法，特别是使用可植入氧传感器进行组织氧合定量测量的电子顺磁共振（EPR）血氧测定法。还介绍了心血管和癌症应用的代表性实例。
