Neuroimmune Interactions and Their Implication in Immune Cell Trafficking in Cardiovascular Diseases and Cancer

Sympathetic nerves innervate bone marrow and various immune organs, where norepinephrine—the primary sympathetic neurotransmitter—directly interacts with immune cells that express adrenergic receptors. This article reviewed the key molecular pathways triggered by sympathetic activation and explored how sympathetic activity influences immune cell migration. Norepinephrine serves as a chemoattractant for monocytes, macrophages, and stem cells, promoting the migration of myeloid cells while inhibiting the migration of lymphocytes at physiological concentrations. We also examined the role of immune cell infiltration in cardiovascular diseases and cancer. Evidence suggests that sympathetic activation increases myeloid cell infiltration into target tissues across various cardiovascular diseases, including atherosclerosis, hypertension, cardiac fibrosis, cardiac hypertrophy, arrhythmia, myocardial infarction, heart failure, and stroke. In contrast, inhibiting sympathetic activity may serve as a potential therapeutic strategy to treat these conditions by reducing macrophage infiltration. Furthermore, sympathetic activation suppresses T lymphocyte infiltration and promotes macrophage accumulation in cancer tissues, which are linked to increased cancer growth and metastasis. Thus, inhibiting sympathetic activation could help protect against cancer by enhancing T cell infiltration and reducing macrophage presence in tumors.