Diabetes Health Talk

Clinicians have known for some time that people treated for HIV also become much more susceptible to diabetes and heart disease. A study by scientists at Sydney’s Garvan Institute of Medical Research has now shown some of the reasons why - enabling better patient management and monitoring.

Associate Professor Katherine Samaras, Head of Garvan’s Diabetes and Obesity Clinical Research Group and senior endocrinologist at St Vincent’s Hospital, has demonstrated that inflammation (typically associated with immune function) plays a much greater role than previously suspected. Her findings were published online last week in the journal Obesity.

“People being treated for HIV tend to lose fat on their arms, legs, face and buttocks and gain it around their abdomen,” said Samaras. This redistribution of fat is termed ‘lipodystrophy’ and those patients with the condition have a cardiac and metabolic risk profile worse than being very obese.”

“We think that in some way anti-retroviral drugs influence fat cells, making them push out inflammatory molecules that contribute to creating the heart disease and diabetes we see in patients.”

Professor Samaras collaborated with Professor Andrew Carr from St. Vincent’s Hospital’s Centre for Immunology to measure the body compositions and metabolic responses of patients with HIV-infection.

MRI and DEXA scans measured fat, muscle and bone mass. Blood tests measured cholesterol, glucose and various molecules involved in heart disease and diabetes, such as tumour necrosis factor-alpha, interleukin-6 and adiponectin. Insulin resistance, which refers to the body’s ability to use insulin to take up glucose, was measured by ‘clamp’.

Cumulatively, the tests showed marked changes in body composition and a dramatic increase in tissue-damaging inflammatory molecules.

Samaras and a number of other HIV specialists published a state of the science paper in July’s Circulation, arising out an American Heart Association meeting. The paper summarised the current understanding of how HIV and its treatments caused body composition changes and increased cardio-metabolic risk.

“In the Circulation paper, we discussed the evidence that these drugs increase the risk of heart disease and diabetes and how important it is to understand the mechanisms. My recent study gives some insights into those mechanisms - and how we might avert them.