Targeting the Vascular Marginated Neutrophil Pool to Enhance Post-Infarct Healing

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Summary of  Nature Communications. https://doi.org/10.1038/s41467-026-71612-8 
Dr. Albert Dahdah et al.

Points

Investigators discovered that the first wave of neutrophils to reach the injured heart after an attack originates from blood vessel walls rather than being newly produced in the bone marrow.
The study found that norepinephrine released during the body’s stress response signals these immune cells to detach and flood the myocardium which causes excessive inflammation and subsequent tissue damage.
Researchers identified that neutrophils arriving at the heart release proteins called alarmins which further signal the bone marrow to increase the production of even more inflammatory cells throughout recovery.
Clinical data in mice demonstrated that using a beta two blocker to interrupt this stress signal successfully limited the number of neutrophils entering the heart and improved overall cardiac function.
The findings suggest that temporarily adding non-selective beta blockers to the standard of care could help patients by reducing hyper-inflammatory injury while still allowing for essential heart muscle repair.

Summary

This study evaluated the mechanism of early neutrophil recruitment to the heart following myocardial infarction (MI) in murine models. While bone marrow granulopoiesis typically peaks days post-infarct, the research sought to identify the source of the rapid, acute neutrophil influx that exacerbates ischemic injury. Using hematopoietic stem cell ablation and flow cytometry, the investigators determined that the initial wave of neutrophils originates from a marginated vascular pool rather than de novo production in the bone marrow or spleen.

The analysis identified the “fight or flight” stress response, specifically norepinephrine-driven beta-2-adrenergic signaling, as the primary trigger for this demargination process. Upon MI-induced catecholamine release, neutrophils adherent to blood vessel walls detach and rapidly infiltrate the myocardium. This early infiltration triggers a secondary signaling cascade via the release of alarmins, which subsequently stimulate the bone marrow to amplify the inflammatory response. Pharmacological inhibition of beta-2-adrenergic receptors or norepinephrine synthesis was found to suppress this demargination, significantly limiting acute cardiac neutrophil infiltration.

The findings suggest that the temporal modulation of adrenergic signaling may improve post-MI recovery. While sustained beta-adrenergic blockade did not yield long-term benefits in this model, transient inhibition during the acute phase successfully enhanced cardiac remodeling and functional preservation. These results indicate that targeting the vascular marginated pool through short-term, non-selective beta-blockade could mitigate hyper-inflammatory injury without compromising the essential healing functions of neutrophils. Future research is required to determine the translational potential of these findings in human clinical populations receiving standard post-MI care.

Link to the article: https://www.nature.com/articles/s41467-026-71612-8

References

Dahdah, A., Maremanda, K. P., Marimuthu, M., Park, K. H., Jaggers, R. M., Chattopadhyay, D., Qiang, W., Nitin, N., Stavrakis, S., Dasari, T. W., Șuicã, V. I., Boteanu, R. M., Uyy, E., Antohe, F., Tilley, D. G., Murphy, A. J., & Nagareddy, P. R. (2026). Β2 adrenergic receptors orchestrate neutrophil demargination and recruitment to the ischemic heart following myocardial infarction. Nature Communications. https://doi.org/10.1038/s41467-026-71612-8