Our researchers are at the forefront of exciting fields. Read about their latest projects and the people who inspire them every day.
For Professor Kazuaki “Kaz” Negishi, climate change has an unexpected impact on the heart
A recent paper by Charles Perkins Centre Nepean researcher, Professor Kazuaki “Kaz” Negishi, was published in Lancet Planetary Health, which showed the increased risk of out-of-hospital cardiac arrest (OHCA) from short-term exposure to low concentrations of fine particulate matter PM2.5.
With Australia’s recent catastrophic bushfire season and its flow-on effects to widespread areas throughout the country, the impacts of P2 particles are becoming more pronounced due to their presence in bushfire smoke – making Kaz’s research more and more topical.
According to Kaz, the mechanism for the PM2.5 effect on cardiac function is threefold:
1. It causes inflammation in the lungs leading to systemic inflammation, which hastens lipid plaque progression;
2. Since they are tiny particles, smaller than red blood cells, they can enter the blood stream and increase plaque progression;
3. They cause an imbalance in the autonomic nervous system leading to oxidative stress.
In the paper, Kaz and his team identified those over 65 years with an underlying medical condition had a higher risk of cardiac arrest with air pollution and this is not conclusive, given the extreme nature of Australia’s bushfire season this year. At Nepean Hospital, there was reportedly a 10% increase in heart attacks in the relatively short but intense period of smoke pollution this summer. Data from other sources is required, and to this end, Kaz and the team hope to secure funding to explore these issues in more detail.
Infants and foetuses too are at risk. The 2014 Hazelwood coal mine fire in Victoria burned for 45 days, exposing local populations, and pregnant women to air pollutants. Thanks to a government grant to investigating pollutant effects on paediatric populations, Kaz’s team showed that children whose mothers smoked and who had been exposed to the coal mine fire during pregnancy had early signs of arthrosclerosis up to as early as 3 years old. Usually the mother’s lungs and placenta filter out these particles, but the burden of pollution meant that some particles reached the developing foetus.
This work is part of a newer field of research called environmental cardiology. In addition to his air pollution research, Kaz collaborates with NASA looking at the effect of microgravity on the heart, which like any muscle, needs exercise to keep it working well in space. He also continues his work in imaging, and in the Obesity Clinic at CPC looks at the cardiac effect of obesity and diabetes.
With his PhD focus on cardiac imaging during his studies in Japan, this specialisation was further honed during his time at Cleveland Ohio as a Research Fellow. Kaz later moved to the University of Tasmania as a Senior Lecturer in Medicine, where he obtained his Australian clinical cardiology qualifications.
Kaz is recognised as an expert in cardio-oncology and runs a clinic at Nepean Hospital. It is known that some chemotherapy regimes damage the heart, which can severely affect patient outcomes. Using cardiac imaging, Kaz monitors oncology patients hourly to detect any heart damage. His collaborators at Charles Perkins Centre are Gemma Figtree, Stuart Grieve, and Ben Freedman.
Professor Negishi is currently the Head of Medicine, Nepean Clinical School, at the University's Faculty of Medicine and Health, a member of the Charles Perkins Centre Nepean, and a cardiologist at Nepean Hospital.
Dr Nick Fuller is an obesity researcher with The Boden Collaboration, Charles Perkins Centre. He works with Ian Caterson, Tania Markovic, and others in the field of metabolic biochemistry, where research is focused on how the body responds to weight loss and the processes that make long term maintenance of weight loss so difficult. Dr Fuller and others see thousands of patients a year in various clinics run at the Royal Prince Alfred Hospital clinic on the ground floor of the Charles Perkins Centre.
Metabolic rate is the amount of energy the body burns at rest. Following diets, the rate slows considerably, by as much as 15%. While weight loss improves metabolic parameters such as cholesterol and triglyceride readings, the metabolic rate seems permanently slowed, and shuts down to regain its former weight.
This observation prompted Nick to complete a PhD in obesity treatments, focused on whether diets are not only effective for the participant, but also cost-effective. His main motivation was to help people and many of those he helped long term in their weight loss struggle he now counts as friends.
The rebound effect is now widely acknowledged by the diet industry. Even now, individual dieters who regain weight will simply try again with a different or the same diet. This leads to a long-term cycle of yo-yo weight losses and gains.
According to Dr Fuller, dieting (intentional weight loss) is one of the factors leading to the obesity epidemic and should be avoided at all costs. The exception are people under clinician’s care, but resources are scarce and only a small minority can access clinician care and advice.
One way of beating the rebound effect is making exercise a regular part of life. Exercise preserves lean muscle mass, and people with more muscle mass are burning more energy when at rest.
Another method of avoiding the dieting rebound effect is through Dr Fuller’s interval weight loss program, which is underpinned by research and evidence. The idea here is to lose a small amount of weight only (2kg-3kg) – the amount found to be clinically significant for reducing the long-term risk of diabetes and cardiovascular disease. After this, the person takes a break (e.g. a month) and simply maintains that 2kg-3kg loss for a while, before losing another small amount of weight. The break allows the body to welcome the weight loss and the metabolic rate does not decrease in the same way it does with large losses.
Another of Dr Fuller's passions is correcting misleading information about diets. He has found it most useful to write for the popular media, through educational pieces in the places where most people consume their health information (or misinformation).
In these pieces, he emphasises a mindset of abundance rather than deprivation – an abundance of whole foods such as fruit, vegetables and nuts, fish, and grains. Part of this education piece is to help people retrain their brains and to eat more good food rather than less. In this way, the same pleasure from fruit nuts and vegies can be gained in a similar way to highly processed foods.