Mayevsky A, Rogatsky GG. Mitochondrial function in vivo evaluated by NADH fluorescence: from animal models to human studies. Am J Physiol Cell Physiol 292: C615-C640, 2007. First published August 30, 2006; doi:10.1152/ajpcell.00249.2006.-Normal mitochondrial function is a critical factor in maintaining cellular homeostasis in various organs of the body. Due to the involvement of mitochondrial dysfunction in many pathological states, the real-time in vivo monitoring of the mitochondrial metabolic state is crucially important. This type of monitoring in animal models as well as in patients provides real-time data that can help interpret experimental results or optimize patient treatment. The goals of the present review are the following: 1) to provide an historical overview of NADH fluorescence monitoring and its physiological significance; 2) to present the solid scientific ground underlying NADH fluorescence measurements based on published materials; 3) to provide the reader with basic information on the methodologies used in the past and the current state of the art fluorometers; and 4) to clarify the various factors affecting monitored signals, including artifacts. The large numbers of publications by different groups testify to the valuable information gathered in various experimental conditions. The monitoring of NADH levels in the tissue provides the most important information on the metabolic state of the mitochondria in terms of energy production and intracellular oxygen levels. Although NADH signals are not calibrated in absolute units, their trend monitoring is important for the interpretation of physiological or pathological situations. To understand tissue function better, the multiparametric approach has been developed where NADH serves as the key parameter. The development of new light sources in UV and visible spectra has led to the development of small compact units applicable in clinical conditions for better diagnosis of patients.real-time tissue viability; tissue spectroscopy; patient monitoring UNDERSTANDING THE MITOCHONDRIAL function has been a challenge for many investigators, including cytologists, biochemists, and physiologists, since its discovery more than 120 years ago. In addition to many books regarding the mitochondria, Ernster and Schatz (79) reviewed the history of mitochondrial structure and function studies. In the past two decades, several studies have reported mitochondrial involvement in pathological processes such as stroke (225) or cytoprotection (77). Most of the information on the mitochondrial function has been accumulated from in vitro studies. A relatively small portion of published papers dealt with the monitoring of mitochondrial function in vivo and in real time. Presently, examination of the involvement of the mitochondrial function in many pathological states, such as sepsis, requires monitoring of patients treated in intensive care units. Unfortunately, real-time monitoring of the mitochondrial function in patients has rarely been performed. The current study pres...
