Brain Research Bulletin Special Issue: Brain-body communication in health and diseases Brain-spleen axis in health and diseases: a review and future perspective.

The spleen filters blood and supports the immune system. New evidence shows it also influences brain function in health and disease through immune modulation. In mice, systemic inflammation or chronic social defeat stress causes spleen enlargement (splenomegaly). The antidepressant arketamine can reverse both splenomegaly and depression-like behaviors in stressed mice. A direct brain-to-spleen pathway exists: neurons in the paraventricular nucleus and central amygdala regulate humoral immune defense. Vagal nerve signaling also contributes to brain-spleen communication. This review summarizes recent findings on the brain-spleen axis.

Study at a glance

Abstract

The spleen, an important tissue for the immune system, acts as a filter for blood within the immune system. Accumulating evidence suggests that the spleen affects a number of brain functions in health and diseases via immune modulation. Systemic inflammation or chronic social defeat stress (CSDS) can cause splenomegaly in rodents. Interestingly, the new antidepressant arketamine could normalize splenomegaly and depression-like behaviors in CSDS-susceptible mice. A recent study strongly supports the direct connection pathway between the brain and spleen, whereby the spleen can regulate the humoral immune defense by the two brain regions, such as corticotropin-related neurons in the paraventricular nucleus (PVN) and the central nucleus of the amygdala (CeA). Furthermore, afferent and efferent vagus nerve signaling may contribute to brain and spleen communication. In this article, we review recent findings of the brain-spleen axis in health and diseases.