According to Dr. Mosser, macrophages can change their physiology and switch types. For example, in healthy, non-obese people, macrophages in fat tend to function as wound-healing macrophages. They are also thought to maintain insulin sensitivity in adipose cells. However, should an individual become obese, macrophages in fat will instead promote inflammation and cause the adipose cells to become resistant to insulin.
Immune-regulating macrophages produce high levels of the cytokine interleukin-10, which helps suppress the body's immune response. Suppressing an immune response may seem counter-intuitive, but in the later stages of immunity it comes in handy because it limits inflammation.
According to Dr. Mosser, immune-regulating macrophages may hold the key to developing treatments for autoimmune diseases such as multiple sclerosis or rheumatoid arthritis. The focus of new research is on reprogramming the macrophages to assume a regulatory phenotype and prevent autoimmunity, he said.
There is broad potential for exploiting different stages of macrophage activation, Dr. Mosser added. "It might be possible to manipulate macrophages to make better vaccines, prevent immunosuppression, or develop novel therapeutics that promote anti-inflammatory immune responses."
The release of interleukin-4 in response to tissue injury not only results in macrophages that specialize in wound-healing, it allows the macrophages to convert arginine to ornithine, which is a precursor of polyamines and collagen. Both polyamines and collagen are instrumental to the formation and maint
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American Physiological Society