Inflammatory findings about cortisol
From out of nowhere, a large dog appears and lunges at you, sinking his teeth into your arm. You may not know how to react, but your body does. Almost instantaneously, you get a rush of adrenaline. At the same time, your cortisol level surges. The role of adrenaline in such a scenario is well known—it helps you to respond by either fighting back or running away. But what role does cortisol play?
A recent paper in the journal Dose-Response by researchers Mark Yeager, M.D., a professor of anesthesiology, Patricia Pioli, Ph.D., an assistant professor of obstetrics and gynecology, and Paul Guyre, Ph.D., a professor of physiology, begins to answer that question.
The surge in cortisol "is preparing the immune system for the subsequent challenge it might see if an infection ensues," Guyre explains. In other words, the temporary spike in cortisol primes the body to react to a secondary threat—in this case, the possibility of an infection from the dog bite—with beneficial inflammation. The interdisciplinary team, with the aid of other scientists and clinicians, reached that conclusion after conducting several different experiments designed to decipher the relationship between cortisol levels and inflammation.
The temporary spike in cortisol primes the body to react to a secondary threat.
First the researchers examined the effects of lowering cortisol to below a normal (or baseline) level. Then they compared the effects of low, medium, high, and very high cortisol levels in patients undergoing cardiac surgery, a procedure that causes a lot of inflammation. And then they tested how varying levels of cortisol might prepare the body for a future infection.
They found that the role of cortisol varies depending on the context. At normal levels, cortisol neither promotes nor suppresses inflammation. When it is at a high level during an acute, stressful event—as when facing a snarling dog—cortisol suppresses inflammation. But several hours after the jump in level, it can promote immune responses.
This dynamic portrait of cortisol is surprising given its well-known anti-inflammatory effects. Hydrocortisone cream quells the itch from poison ivy, for example, and a cortisone shot to an injured joint minimizes painful swelling.
"Because so much of human disease . . . is a complication of inflammation," says Yeager, "all anyone wanted to think about, literally for decades," was cortisol's anti-inflammatory effects.
Yeager, a specialist in critical care medicine, believes that if doctors have a better understanding of how cortisol acts in the body at different times and under different circumstances, they might discover better ways to treat patients.
"Anything in which inflammation is involved could potentially be affected," Yeager says. That includes infections from overly aggressive dogs.
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