Chemical assembly of N-glycans by use of modular building blocks

Abstract

G and free fatty acids (FFA) are the predominant metabolic substrates in heart. Their relative uptake in normal hearts varies with the metabolic milieu (fed/fasting state), plasma levels and insulin levels. Myocardial ischemia results in a profound up-regulation of glucose and down regulation of FFA metabolism. Fluorine-18 labeled deoxyglucose (FDG); a glucose analogue is used extensively in clinical practice for imaging glucose metabolism in heart, tumors and other organs. Alternations in glucose metabolism accompanying several disease conditions can be used to diagnose these conditions. Exercise results in ischemia and up-regulates glucose uptake in regions perfused by diseased coronary arteries. This can be used for developing a non-invasive diagnostic imaging test for coronary artery disease (CAD). We evaluated the diagnostic potential of exercise FDG imaging for CAD and compared it with exercise-rest myocardial perfusion imaging (MPI), an established and routinely used test. FDG imaging had higher diagnostic sensitivity compared to MPI. Furthermore, increased regional FDG uptake is observed only on exercise images. Persistence of FDG uptake 24 hours later is seen in less than one third of cases and is indicative of more severe CAD. Cardiac imaging using radiolabeled sugars is a highly promising new diagnostic test for CAD and may also provide a powerful tool for studying the pathophysiology of myocardial ischemia.