Inflammation in the body is an important mechanism that helps to heal. But, as is well known, it can also create problems by aggravating injuries and intensifying various medical conditions. Researchers at the Wyss Institute at Harvard University have been working on getting a handle on the process of inflammation so as to be able to better guide how it heals the body.
The team has focused on being able to switch macrophages, the white blood cells of the immune system found at sites of injury and infection, between their two primary inflammatory states. Normally, the cells are first in their M1 state, which results in the production of molecules such as inflammatory cytokines and antimicrobial peptides, and then they eventually switch to the M2 state, in which inflammation is reduced and tissue fibers are allowed to mature. The issue is that the body is not very good at deciding when to switch between M1 and M2, too often resulting in continued inflammation when it’s time to let tissues heal and regenerate.
The team was able to take IL-4, a natural anti-inflammatory cytokine, and attach many molecules of it to the surface of gold nanoparticles, which when injected into injured mice caused the macrophages to switch from M1 to M2 and to significantly speed up overall healing. IL-4 has been used in the past to control inflammation, but the systemic delivery to large parts of the body without being able to target it well to the site of injury have limited its practical application. The new findings, reported on in Proceedings of the National Academy of Sciences, will hopefully lead to new therapies for chronic muscle diseases such as Duchenne Muscular Dystrophy and for common sports injuries experienced by most people at some point throughout their life.
Image: Stains for cellular components (pink) and muscle fibers (red) in mouse muscle injected with IL-4 nanoparticles show that a muscle that received treatment (right) displayed better regeneration of muscle cells and less empty space in the muscle tissue (white) than a muscle that did not receive treatment (left). Credit: Wyss Institute at Harvard University
Study in Proceedings of the National Academy of Sciences: Functional muscle recovery with nanoparticle-directed M2 macrophage polarization in mice…
Via: Wyss Institute…