Some people may forget that the skin is the human body’s largest organ, and it has many diverse functions. Now, researchers realize that regulating blood pressure and heart rate is one of those functions, and a collaboration between University of Cambridge and Karolinska Institute scientists breaks down the intricate details of how the skin is involved in regulating blood flow through small vessels.
What causes changes in blood pressure, specifically? It’s not exactly clear, but scientists do know that things like high altitude, pollution, smoking, and obesity can all influence changes. "Nine of ten cases of high blood pressure appear to occur spontaneously, with no known cause," explained Cambridge’s Randall Johnson.
Whatever the specific cause, increases in blood pressure can quickly become dangerous if left untreated, leading to heart attack, stroke, and other cardiovascular diseases when blood flow through small vessels, like those in the skin, changes. By examining the skin instead of other organs classically studied in the context of blood pressure - brain, heart and kidneys - the present study yields unique findings.
Whatever the reason, when a tissue is oxygen deficient, the body redirects blood flow as a response. This is a mechanism highly regulated by a family of proteins called “HIF.” So when the team of researchers began their study of the skin and blood pressure, they started with HIF.
First, researchers watched how mice, genetically modified as unable to produce particular HIF proteins in the skin, responded to low oxygen conditions. They observed a so-called “feedback loop” between the skin and the cardiovascular system. “By working with mice, we were able to manipulate key genes involved in this loop,” Johnson explained.
They saw that when mice lacked one of two HIF skin proteins, HIF-1α or HIF-2α, the response to low oxygen levels changed compared to mice sufficient with both proteins, impacting heart rate, blood pressure, and skin temperature.
Next, researchers looked at the response of normally, genetically-unaltered mice to oxygen starvation. Losing HIF proteins had an enormous influence on the initiation and duration of this process.
“Our skin's response to low levels of oxygen may have substantial effects on the how the heart pumps blood around the body," explained first author Dr. Andrew Cowburn. "Low oxygen levels - whether temporary or sustained - are common and can be related to our natural environment or to factors such as smoking and obesity.”
The present study was published in the journal eLife.
Source: University of Cambridge