Researchers at WashU Medicine’s Center for Cardiovascular Research have discovered that specialized immune cells from the spleen play a critical role in healing the heart after a heart attack. The study, led by Sumanth Prabhu, MD, Division Chief and director of the Prabhu Lab, identifies a unique population of macrophages—immune cells that clean up cellular debris—that travel from the spleen to the heart to support tissue repair and reduce long-term damage.
Using advanced mouse models and a range of techniques including single-cell RNA sequencing, cell tracking, and splenectomy, Prabhu and his team demonstrated that CD169⁺Tim4⁺ macrophages originating in the spleen are essential to the wound healing process following a heart attack (also called myocardial infarction, or MI). The study also examined blood samples from human patients and found similar immune cell activity, suggesting that this healing pathway exists in people as well.
Following MI, these spleen-derived cells mobilize to the heart, where they help clear out dead cells, calm excessive inflammation, and encourage regeneration of heart tissue. Mice lacking these macrophages showed worse inflammation and more scarring, while increasing the number of these cells through drug treatment improved both short- and long-term recovery of heart function.
The findings were recently published in Circulation, and highlight the potential of therapies that boost or mimic the reparative functions of spleen macrophages to prevent long-term heart damage.