Hypertension: making the silent killer audible

Cardiovascular disease is New Zealand’s single biggest killer, resulting in a death every 90 minutes. Its greatest risk factor? Hypertension, or high blood pressure. “At least 25 percent of the population in New Zealand has high blood pressure,” says Julian Paton, Professor of Translational Physiology and director of Manaaki Manawa, the Centre for Heart Research at the University of Auckland. “This makes us more susceptible to nasty cardiovascular events, such as heart attacks, stroke, renal failure, retinopathies, than any other risk factor. It’s crucial that we better understand and control it.”

Hypertension is especially dangerous because it is asymptomatic, earning its name “the silent killer”. Many Kiwis are unaware they even have high blood pressure, and of those who are, 50 percent remain hypertensive even when on medication.

How can we improve control of blood pressure? That is a question Julian hopes to answer with Dr Amanda Dixon-McIver, laboratory director at IGENZ. In November they were named as the inaugural Partridge Laureates, a programme created by Partridge Jewellers in celebration of their 160th anniversary with the aim of making a positive, lasting impact on New Zealanders’ health. They are working on a two-pronged research project encompassing the development of a new diagnostic to better control hypertension and subsequently reduce deaths.

The first step is understanding why blood pressure medication has such a poor success rate. This is largely due to a lack of individual patient assessment and an empirical prescription approach, Julian explains. “When a GP prescribes drugs for high blood pressure, no diagnosis is made as to why your body has generated this condition.” Added to this is the fact that all available hypertension medications have been around for more than 20 years and were originally tested on a predominantly Caucasian population.

 Julian, Amanda and a team of talented researchers and scientists are developing cutting-edge DNA screening to reveal best blood pressure medication. If successful, it would be the first of its kind in the Southern Hemisphere. While they can’t share much during the development phase, the research is expected, through genetics, to accurately predict the most effective drug or drugs for hypertensive patients that would assist GPs to more quickly treat their blood pressure. “We’re hoping to create a test that can be done at the GP’s practice or at the bedside,” explains Amanda. “This would tell you which drugs you are most likely to respond to, taking away the guesswork that occurs at the moment and enabling a degree of personalised medication based on your genetic makeup.”

After validating the screening exercise in hypertensive people, they will then apply it to patients who also have diabetes, as in this group high blood pressure is even more difficult to control. “Aotearoa New Zealand is an epicentre for hypertension with diabetes, so this approach will be really important and improve equity for our Māori and Pacific patients,” says Julian.

The team also plan to preclinically trial a new form of therapy to control blood pressure in hypertension. Having established a connection between the body’s autonomic nervous system and high blood pressure, they will test an existing medication approved in Europe for human use for a different disease. Should it work, they will progress to first-in-human trials and develop New Zealand’s first blood pressure drug in 25 years. “This will be a completely new type of medication affecting a different system that we believe is out of control in many patients and not responding to current therapy,” says Julian.

Auckland’s ethnically diverse population makes it an attractive location for their research, says Julian – in fact, it’s why he moved here from Bristol, England in 2017. “What brought me here is the opportunities to do things that I could not do in the UK. The University of Auckland is conducting world-class research, things that no one else is doing around the world. The skill base and the facilities here are second to none. This is ideal for early discovery research, and that's what allows us to compete at the international level.”

Within the next 18 months, Amanda and Julian anticipate confirming the project’s viability. First-in-human trials would follow, and they are excited about the potential impact this could have on New Zealanders’ health. “High blood pressure can be the starting point that triggers a sequelae of diseases later in life, so treating it effectively is crucial for preventing downstream adverse events,” Julian explains. Successfully managing hypertension would keep more Kiwis out of hospital, significantly lowering the financial burden and resource strain on our healthcare system. A healthier society also means more people at work, generating tax income. “New Zealand has a limited ability to generate GDP. That’s a problem, because the percentage of GDP that goes into research is insufficient.” 

This makes philanthropic funding more valuable, and Julian and Amanda are grateful to the Partridge Family Foundation for supporting their work. “It’s humbling and I’m hugely honoured to be one of the first Partridge Laureates,” says Julian. “What they’ve done not only gives us an opportunity to do something we couldn’t do before, but provides the family with a legacy of national impact for improving the heart health and well-being of a nation.”

The family’s support will go a long way towards helping New Zealanders live longer, healthier lives, Amanda says. “This project has the potential to change people’s lives in our own country as well as globally. It’s fantastic that the Partridge Family have given us the opportunity to bring it to fruition.”