Immunometabolism, an emerging field in perioperative and critical care medicine: a narrative review

Metabolism and immune function are tightly intertwined, and have been the focus of research in the expanding field of immunometabolism. Immunometabolism focuses on the metabolic adaptation of immune cells to their environment, allowing an efficient and targeted immune response even in hypoxic or nutrient-depleted tissue. The inflammatory response can be pathologically altered in chronic metabolic disease or acute injury as a result of poor immunometabolic adaptation, contributing to short- and long-term complications. Novel techniques, including 'omics' investigations, advanced imaging, and phenotyping with flow cytometry, now allow for in-depth and near real-time profiling of the intricate interactions between cell function and metabolism. Although this has significantly increased our knowledge of immunometabolic consequences in the fields of diabetes mellitus and cancer, it has been largely underappreciated in the perioperative period, even though the perioperative period serves as a strong translational model to investigate complex and highly dynamic metabolic shifts in acute inflammation. Interventions to modulate immunometabolism are being explored, particularly through immunonutrition in critical care, with heterogeneous results underscoring the need for greater understanding of the complex underlying mechanisms. In this review, we describe immunometabolic adaptation in health and metabolic disease, and under the acute inflammatory stress caused by surgery. We also discuss potential interventions, including immunonutrition and mode of anaesthesia to modulate immunometabolism in the perioperative period and critical illness.