Medical Faculty News v25i1

Obesity is associated with serious health problems, such as diabetes, cardiovascular diseases and some cancers. Work by Dr Hannah Hui Xiaoyan , Research Assistant Professor of the Department of Medicine, is helping to unlock the mechanisms involved and reveal new drug targets to reduce obesity. Dr Hui’s work focuses on adipose tissue, an organ that was once believed to be an inert organ simply responsible for storing lipid in the body. But now we know that adipose tissue is a highly dynamic and heterogeneous organ. It is the largest endocrine organ in the body and plays a pivotal role in the body’s shift from a healthy state to an obese, unhealthy one. There are two types: white adipose tissue stores excess energy and is related to chronic inflammation, which is a bad guy in numerous diseases, while brown adipose tissue burns energy and help the body to clean up excess glucose and lipid. It is this latter type that is of most interest to Dr Hui. Brown adipose tissue was not discovered in adult humans until about ten years ago – it was previously thought to be present only in certain types of animals and newborn babies. New imaging technologies made the discovery possible, but there is still much to discover about this organ. “I am very interested in elucidating how this energy-burning, good adipose tissue is activated in our body. I wish my research could eventually lead to effective pharmacological ways to activate or generate it, since I strongly believe this could help people to lose weight and solve other related complications,” Dr Hui said. In one project, she and her team found a connection between brown adipose tissue and the protein adiponectin. When mice were exposed to cold temperatures, the expression of adiponectin in their white adipose tissue increased and this in turn increased the amount of brown adipose tissue. When the mice were deficient in adiponectin, this did not happen. The scientists were also able to explain how the protein acted to increase browning by influencing the immune system, which in turn acted back on the adipose sites. “It’s a kind of cross-talk between cells in the adipose tissue. This relates to a new concept, immunometabolism. We are among the first to provide evidence that immunity and metabolism are closely associated,” she said. To carry that work forward, Dr Hui recently received funding from the Excellent Young Scientists Fund of the National Natural Science Foundation of China. She is looking at the protein UCP1, which enables brown adipose tissue to generate heat. Her previous research had led her to suspect there are other pathways besides UCP1 that are equally or more important in heat- generation and she now wants to uncover these. Alongside that research, her team is exploring strategy for adipose-targeted delivery, which will maximise the anti-obese capacity of the drug to be delivered, without harming other organs. So far, the results look promising in mice and she hopes this can be applied to human tissue in near future. The Fat Buster I am very interested in elucidating how this energy-burning, good adipose tissue is activated in our body. I wish my research could eventually lead to effective pharmacological ways to activate or generate it, since I strongly believe this could help people to lose weight and solve other related complications. 18 Feature