Professor Michael Horowitz AO

Michael Horowitz’s mother was the only woman in her class studying science at Charles University in Prague when the Nazis invaded in World War II. His father had a doctorate in agricultural sciences from one of Europe’s oldest universities, in Krakow, Poland.

It is not surprising that young Michael, now Professor Michael Horowitz, would follow the path of research.

Science, like The Force in Star Wars, ran strong in the Horowitz family – to the extent that Professor Horowitz is an author of 767 peer-reviewed papers and 41 book chapters. He is responsible for ground-breaking research into the importance of gastric emptying in people with diabetes – work for which he was in June made a Member of the Order of Australia (AO).

Professor Horowitz’s father moved to Adelaide for a position as Head of Plant Genetics at the Waite Institute. His parents’ sustained love of Adelaide was instilled in him from birth and he has never left.

‘There were clear messages of the importance of people, the importance of Australia and the importance of scientific endeavour during my childhood, as well as that of classical music and good food, particularly Czech cakes,’ he remembers.

‘I’ve always been aware that money and possessions can be taken away, but what you did with your head, and particularly scientific endeavour relating to other people, were extremely important and meaningful.’

Yet he says that his interests in gastroenterology and endocrinology, which led to his King’s Birthday Honour, were mainly a matter of serendipity.

Having the good fortune to work with eminent supervisors and mentors – gastroenterologist Professor David Shearman and endocrinologist Dr Philip Harding – on a PhD focusing on the rate at which the stomach empties in people with diabetes, Professor Horowitz set his sights on a career as a clinician-scientist.

‘I was very fortunate with both my timing and the research environment. David Shearman and Phil Harding both encouraged me, and I recognised that I wanted to pursue a career as a clinician-scientist. The seeds, however, had clearly been sown by my parents.

‘The environment in Adelaide to support the development of clinician-scientists – doctors, nurses, dieticians, or, like my wife, with a background in nuclear medicine, was much better than it is today.’

Professor Horowitz recognised that there was a need for an improved understanding of the function of the gastrointestinal tract in diabetes. He says there are two interrelated elements: first, abnormal gastrointestinal function occurs very frequently in people with diabetes - in the broadest sense, probably as a result of nerve damage. In the 1980s, he and his team showed that about 50% of people who have longstanding type 1 or type 2 diabetes have abnormally delayed stomach emptying (gastroparesis).

The second element was that the rate the stomach empties is a major determinant of the magnitude of the rise in blood glucose after meals. It was thought that everyone’s stomach emptied at about the same rate, but he found there is about a four times variation in health, which is even greater in people with diabetes.

‘This has changed clinical practice, with the development of new drugs to improve blood glucose control in people with type 2 diabetes, by modulating the rate the stomach empties, including agonists of the hormone, glucagon-like peptide-1 (GLP-1 receptor agonists),’ he says.

‘The latter have recently been in short supply, as their efficacy to also induce weight loss in obese people, with and without type 2 diabetes, has been appreciated.’

He says it’s not a lack of willpower that about 95% of people who lose weight by diet, exercise or medication put it back on again.

‘When people lose weight, it induces a number of potent mechanisms to favour weight regain. If you are going to treat obesity with medication, it is only logical for medication, if effective and well tolerated, to be continued in the long-term.

‘It’s like suggesting that someone with treated hypertension who has a normal blood pressure should have their antihypertensive medication stopped.

He says the need for non-surgical treatment for obesity to be sustained poses a quandary for health administrators, ‘given that some 65% of adult Australians are overweight or obese’.

Clinical research remains a major interest for Professor Horowitz. He and his wife, Professor Karen Jones, continue to work together at the University of Adelaide’s Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, which he leads. The Centre continues to explore gastrointestinal motor, sensory, and hormonal function, particularly in the context of diabetes, appetite regulation, critical illness and ageing.