This research may hold considerable importance for a broad audience, encompassing individuals engaging in fasting for health advantages, and researchers specializing in neuroscience and immunity. In fact, the nervous system has long been implicated in orchestrating large-scale immune cell migration (Pavlov and Tracey
2017). Pioneering studies have revealed the intricate connection between the nervous and immune systems, highlighting how specific neural circuits and brain regions influence the stressed-induced, counter-directional shifts in leukocyte populations. A fasting/refeeding-induced mechanism underscores the temporal dynamics of diet in modulating monocyte lifespan, which also involves a CXCR4 response mediated by corticosteroid and monocytic glucocorticoid receptor NR3C1 via the HPA axis (Janssen
et al. 2023). Poller
et al. demonstrate that motor circuits induce rapid mobilization of neutrophils from the bone marrow to peripheral tissues, while the paraventricular hypothalamus controls monocyte and lymphocyte dynamics between secondary lymphoid organs, blood, and bone marrow through glucocorticoid signaling, finally participating in the altered susceptibility to infection, injury, and systematic inflammation (Poller
et al. 2022). More evidence from diabetes research suggests a role for sympathetic neuronal activation in the generation of inflammatory myeloid cells from hematopoietic progenitor cells. Myeloid cell numbers strongly correlated with plasma norepinephrine levels in diabetic patients, and mice lacking tyrosine hydroxylase (TH)-producing leukocytes exhibited diminished granulocyte macrophage progenitor (GMP) proliferation, highlighting the role of catecholamines in modulating hematopoiesis and leukocyte hemostasis (Vasamsetti
et al. 2018). In addition to the cooperation of neural catecholaminergic circuits, vagus nerve–splenic nerve reflex, Pavlovian conditioning and reward system, as well as brain integration of neuroimmune pathways are also involved in the neural regulation of immunity and inflammation (Carnevale
et al. 2016; Schedlowski and Pacheco-López
2010; Udit
et al. 2022). Understanding the depth and selectivity of the nervous system's regulatory control over immune function will be crucial for monitoring and modulating immune homeostasis and maximizing efforts in implementing effective strategies for aberrant immune responses.