Mitochondrial respiration and nucleotide profiling in human left internal mammary artery from CABG: a novel real-time ex vivo approach.

Abstract

Mitochondrial dysfunction plays a critical role in the pathogenesis of cardiovascular and metabolic diseases. However, direct assessment of mitochondrial respiration in human vascular tissue remains technically challenging. In this study, we present an ex vivo approach for real-time analysis of mitochondrial respiration in human left internal mammary artery (LIMA) grafts obtained during coronary artery bypass grafting (CABG). LIMA segment was collected intraoperatively and processed for bioenergetic assessment using the Seahorse XF Flex 3D Analyzer. Mitochondrial respiration was evaluated using the Mito Stress Test, enabling real-time measurement of oxygen consumption rate (OCR). In parallel, tissue nucleotide levels were quantified using high-performance liquid chromatography (HPLC), allowing complementary assessment of cellular energy status and redox balance. We demonstrate the feasibility of measuring mitochondrial respiration in intact human arterial tissue ex vivo. To our knowledge, this is the first application of the Seahorse XF Flex 3D platform for real-time bioenergetic analysis in intact human vascular tissue. Combined analysis of OCR and nucleotide levels enabled integrated assessment of vascular bioenergetic status. The applied protocol enabled reliable assessment of key bioenergetic parameters, including basal and maximal respiration. This study establishes a novel proof-of-concept workflow for ex vivo bioenergetic profiling of human vascular grafts, providing a platform for future investigations of vascular metabolism in cardiovascular and metabolic disorders.