Chance discovery offers new treatments for high blood pressure

Research into the effects of zinc-based drugs on brain function has led to a surprising discovery that looks set to benefit the millions worldwide suffering from a host of cardiovascular diseases, including angina, stroke and hypertension.

While researching the brain, scientists at the Florey Institute and Melbourne University, working in collaboration with researchers at the University of Vermont and TEDA International Cardiovascular Hospital in China, found zinc-based drugs produced a “pronounced and unexpected decrease in blood pressure” in mouse models. They then spent several years working out why and how this could be applied to humans.

In an article for Pursuit, Dr Ashenafi Betrie and Associate Professor Scott Ayton, from the Florey Institute of Neuroscience and Mental Health, and Associate Professor Christine Wright, from the University of Melbourne, explain how the discovery can assist those suffering heart disease and hypertension.

“Your movements, your thoughts, the constant operation of your organs, all depend on your arteries channelling oxygen-rich blood to where it’s needed, releasing energy to fuel every function of your body,” they wrote.

“As the muscles contract, they narrow the artery and increase the blood pressure, and as the muscle relaxes, the artery expands and blood pressure falls.

“If the blood pressure is too low, the blood flow won’t be enough to sustain your body with oxygen and nutrients. Too much blood pressure and blood vessels risk being damaged or even ruptured.”

Read more: Older Aussies with high blood pressure need to check their meds

They say that understanding how this works and how to treat blood flow issues is incredibly important for a host of diseases affecting the heart and blood circulation system, including angina and stroke.

High blood pressure or hypertension is the leading modifiable risk factor for cardiovascular diseases and premature death worldwide. The Australian Institute of Health and Welfare (AIHW) reports that about one in three people aged 18 and over have high blood pressure and that men are more likely to have uncontrolled high blood pressure than women.

The proportion of adults with uncontrolled high blood pressure increased with age – from 10 per cent or less among 18 to 34-year-olds (10 per cent for men, 4.9 per cent for women) to a peak of 47 per cent at age 85 and over (51 per cent for men, 48 per cent for women).

The researchers explained that the effects of potassium and calcium in regulating how blood vessels expand and contract was well known. But their new research, published in Nature Communications, showed the importance of another metal that is abundant in our cells – zinc.

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The discovery creates a potential new pathway for developing treatments for a range of cardiovascular diseases, they say.

“Potassium regulates calcium in the muscle, and it is calcium that has been well studied and recognised for causing the narrowing of the arteries and veins that elevates blood pressure and restricts blood flow,” they wrote.

“This biology is well established, and many drugs have been based on this understanding …”

“Our discovery that zinc is also important was serendipitous because we’d been researching the brain, not blood pressure …

“Eventually, our work showed that coordinated action by zinc within sensory nerves, endothelial cells and the muscle of arteries, triggers lower calcium levels in the muscle of the blood vessel. This makes the vessel relax, decreasing blood pressure and increasing blood flow.

“Essentially, zinc has the opposite effect to calcium on blood flow and pressure.”

The researchers said it was surprising the role of zinc had not previously been appreciated.

Read more: Five ways to lower blood pressure

So, is it as simple as ensuring we have sufficient zinc in our diet?

Not so, they say, because the zinc that makes it into our blood must be transported into our blood vessel cells in a highly regulated process.

“But, there are compounds that can trick cells to increase or decrease their zinc levels, and these compounds might be the basis for new therapeutic drugs,” they said.

The researchers said that while there was a range of existing drugs to lower blood pressure, many people developed resistance to them, and new zinc-based drugs might provide new opportunities.

“There are also a range of cardiovascular diseases that are poorly treated by currently available drugs, including pulmonary hypertension, where zinc-based drugs may warrant investigation.”

Do you suffer from high blood pressure? Does medication control the problem? Are there side-effects that mean you can’t take it for an extended period? Why not share your experiences in the comments section below?

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Written by Janelle Ward



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