Fingerprinting of metabolic states by NAD(P)H fluorescence lifetime spectroscopy in living cells: A review

SummaryChange in metabolic pathways is an important indicator of modifications in physiological, pathological and/or differentiation state of the cell. Its non-invasive investigation can significantly improve medical practice, namely the determination of the suspected tissue during surgery, including fast biopsy used for pre-operative tissue diagnostics, and/or resection guidance during surgical operations. Early detection of these changes is a prerequisite of fast and precise diagnostics directly in living cells and tissues and is thus crucial for the patient's survival and/or his/hers better quality of life. In this contribution, we review time-resolved fluorescence measurements of endogenous NAD(P)H in cells and tissues aimed at separation of specific metabolic pathways (glycolysis vs. oxidative phosphorylation – OXPHOS). Other complex situations, including the presence of oxidative stress, are also discussed. Current state of knowledge on non-invasive diagnostics of pathophysiological state in living cells and tissues, based on time-resolved autofluorescence, is presented.