Research conducted at St. George’s, University of London has led to the discovery of a possible biological catalyst for the development of hypertension. Blood pressure levels are known to be influenced by three factors: heart rate, flexibility of the arteries, and the amount of blood circulating through blood vessels. An imbalance in the chemicals involved in these factors is believed to be the main cause of high blood pressure, but what triggers these chemical imbalances that cause hypertension is still unknown.
According to the American Heart Association, 1 in every 3 deaths in the United States is attributed to cardiovascular disease, and 33.5% of US adults have hypertension. People with hypertension have a significantly larger risk of experiencing heart failure, kidney disease, strokes, and heart attacks.
Researchers at St. George’s found that the role of a potassium channel known as Kv7.4 might be a key factor in the progression of hypertension. This protein is found in the renal artery, the main blood supplier for the kidney. Kv7.4’s role is to relax the arteries, and allow potassium to flow out of muscle cells and into the blood vessels. Kv7.4 channels tell the vessels to expand and allow oxygen and blood to flow to tissues where they are needed. Adrenaline is one of the triggers that tell the Kv7.4 channel to relax or contract vessel muscles.
Laboratory studies have revealed that when a Kv7.4 channel is inactivated, the body doesn’t respond to the triggers signaling it to expand the artery, so blood flow is constricted. If this happens in one or two arteries, researchers state that it probably won’t result in high blood pressure. Inactive Kv7.4 channels may just be a “tipping point” that eventually leads to hypertension once there is an increase in other risk factors.
The research did not investigate how kidneys react to arteries that have been constricted by inactive Kv7.4 channels. However, they know that when the kidneys have an insufficient blood supply, they react by releasing an enzyme called renin, which flows throughout the blood and tells blood vessels to narrow and constrict. This results in an increase in blood pressure.
In future treatments, these channels could be stimulated in order to dilate arteries and lower blood pressure. More research is needed before treatment that regulates the activity of Kv7.4 channels can be developed, but these findings change the understanding of how hypertension develops.