Macrophage Polarization in Aging is Complicated and Poorly Understood

Macrophages are a type of innate immune cell, and like all immune cells are involved in a great many processes in the body, ranging from tissue regeneration to clearing out molecular waste and debris to destruction of pathogens. Macrophages, and the similar microglia of the central nervous system, adopt different phenotypes, known as polarizations, depending on environment and the task at hand. The M1 polarization is pro-inflammatory and focused on ingestion of pathogens and debris, while the M2 polarization is anti-inflammatory and focused on regeneration. These are broad buckets and as such not truly representative of the real complexity of types and behaviors in these cell populations, but they are helpful enough for researchers to consider therapies based on forcing macrophages to preferentially adopt one polarization over another. Earlier work on macrophage polarizations in aging suggested that issues arise with a growth in M1 populations and reduction in M2 populations, mirroring the rising chronic inflammation of aging. Matters are more complicated and tissue specific than that, however. To pick one illustrative example, today's open access commentary looks at what is known of polarization in the aging of muscle tissue, where the opposite trend is observed. The collective activities of cells, like cell metabolism itself, is a ferociously complicated domain and varies widely from tissue type to tissue type within the body. How these aspects of our biology change ...
Source: Fight Aging! - Category: Research Authors: Tags: Medicine, Biotech, Research Source Type: blogs