Main description

The growing body of evidence on the role of the gut microbiota (GM) in regulating the bidirectional gut-brain axis suggests the existence of a complex network that also involves the immune system (IS). The interaction between GM and IS is crucial for the development and modulation of immune responses, through microbial metabolites such as short-chain fatty acids (SCFAs), which influence both mucosal immunity and neuroinflammation. SCFAs regulate immune homeostasis and the function of the blood-brain barrier (BBB), affecting microglia, astrocytes, and neurons. These mechanisms are particularly relevant in neurological disorders such as Parkinson's disease, where dysbiosis and SCFA alterations contribute to neurodegeneration. Although most results derive from preclinical studies and should be interpreted with caution, the use of probiotics, prebiotics, and postbiotics represents a promising therapeutic approach. The "microbiota-immune-brain" model opens new insights for the prevention and treatment of neurological and psychiatric disorders, although larger and more specific clinical trials are needed to confirm its applicability in humans.