Inner ecosystem: understanding the gut microbiota

18 September 2017

The digestive tract is an intricate ecosystem, with gut microbiota reacting to and determining other bodily processes. Dr Sunny Wong studies host-microbial interactions with a view to clinical translation.

The digestive tract is an intricate ecosystem, with gut microbiota reacting to and determining other bodily processes.

While we know the basic function the microbial organisms in helping digestion, their role in affecting our energy and metabolism, appetite, weight, and other physiological functions are less understood. Disorders including diabetes, cardiovascular disease, and some cancers are now known to be related to the function of gut microbiota.

Dr Sunny Wong (Croucher Clinical Assistant Professorship 2013) is a clinician-scientist specialising in internal medicine and digestive diseases. Wong’s primary research interest is to understand the host-microbial interaction and explore it for clinical translation.

“The neurological and psychological effects are still understudied, but one out of ten neurons in our body are present in the gut, which is why it is sometimes called the second brain,” Wong says, “For example, people with depression or developmental disorders have a different gut flora composition.”

“On some level, people have always known that the digestive system is an essential indicator of overall health and wellbeing—look at any traditional medicine practice - but we’ve only started appreciating the depth of gut microbiota in the last decade since we haven’t been able to culture and identify many of them before now”.

As a clinician-scientist Wong works at the interface of science and medicine. Building on clinical training in internal medicine, gastroenterology, and hepatology, as well as a research background in molecular genetics, Wong now splits his time between studying gut microbiota and treating patients.

“Clinical medicine gives me specialised knowledge of the human body, how it can go wrong, and what can be remedied, which helps me to orient my research towards questions that can have a direct impact on people,” he explains.

Wong and his team have spent time analysing the actions of individual microbiotic components. His research has focused on colorectal cancer, which presents an extreme environment, making gut microbes and other markers easier to monitor. Initial screening studies looked at stool and mucosal microbes in patients with and without cancer, mapping how the microbes changed from a healthy environment to different stages of the disease. This established a basic understanding of the bacterial composition of the cancer microenvironment, and led to the discovery of some bacteria which promote tumorous polyps, present at higher levels in cancer patients.

Like many young people, Wong originally chose to study medicine because he was passionate about helping people firsthand, and after beginning his studies, he decided to improve his research skills. He joined the MBChB programme at the Chinese University of Hong Kong to complete his medical training, and afterwards took three additional years to study for a PhD at the University of Oxford. He worked on the genetics of tuberculosis, leprosy, and malaria, diseases, developing skills genomics which he now uses in a microbiological setting.

“There’s really going to be a boom in new ideas and treatments related to the digestive ecosystem in the next few years, now that clinicians are appreciating its role,” Wong notes, “Not just to reverse or treat disease, but also to define what the best balance is for each body, and how to maintain individually beneficial states.”


Dr Wong is a clinician-scientist specialising in internal medicine and digestive diseases. Born and raised in Hong Kong, Wong completed his Medical Degree with Honours at the Chinese University of Hong Kong in 2006. After his medical internship, he went on to pursue his postgraduate study at the University of Oxford, under the supervision of Professor Adrian V. S. Hill on human genetics. In his dissertation, he has identified several major genetic loci contributing to tuberculosis, leprosy and malaria. Wong received his Doctor of Philosophy degree in 2010. Following his doctorate degree, Wong carried on his clinical training in internal medicine, gastroenterology and hepatology. He was admitted as a Member of the Royal College of Physicians (UK) in 2012, a Fellow of the Hong Kong College of Physicians and the Hong Kong Academy of Medicine in 2016. 

He joined the Chinese University of Hong Kong as an Assistant Professor in 2013.


To view Dr Wong’s Croucher profile, please click here.