Glial cells in the heart: Implications for their roles in health and disease

Glial cells are essential regulators of brain homeostasis by orchestrating neuronal function, metabolism and immune responses. However, much less is known about peripheral glial cells, particularly those in the heart. This review explores the development, types and functions of cardiac glial cells, including Schwann cells, satellite glial cells and recently identified cardiac nexus glia, with some reference to their central nervous system counterparts. The heart's autonomic nervous system consists of sympathetic and parasympathetic nerve fibres, primarily located in the epicardial fat pads within the transverse and oblique sinuses and around the roots of the great vessels. Schwann cells support cardiac repair by myelinating neurons and modulating inflammation, while satellite glial cells regulate the neuronal microenvironment, influencing heart rate and rhythm. Cardiac nexus glial cells interact with both sympathetic and parasympathetic pathways to regulate heart function. Understanding the roles of cardiac glial cells could provide new insights into neuro-cardiac interactions and reveal potential therapeutic targets for cardiac disorders.