LAUSR

The development of a sensitive assay using an extracellular flux analyzer has enabled the determination of lactate, the end product of glycolysis, by measuring the pH (extracellular acidification rate; ECAR) of living cells, such as circulating leukocytes. Mitochondrial oxidative phosphorylation can also be simultaneously measured by measuring the oxygen consumption rate (OCR). The basal OCR/ ECAR ratio is a marker of the relative use of glycolysis and oxidative phosphorylation (OXPHOS). Among various immune-mediated cells, OXPHOS is highest in lymphocytes (2.87 ± 0.22 pmol O2/mpH), followed in decreasing OXPHOS by monocytes (1.24 ± 0.13 pmol O2/mpH) and neutrophils (0.47 ± 0.08 pmol O2/mpH) [1]. The amount of energy produced and the balance between glycolysis and mitochondrial OXPHOS are critical factors in the immune responses mediated by the activation of the various immune-mediated cells. Hyperglycemia, chronic inflammation and hyperinsulinemia observed in type 2 diabetes and obesity may affect the metabolic program in immunemediated cells and generate harmful effects on the immune defense against infection and carcinogenesis. Neutrophils