Dr Marlou Dirks
Sir Henry Wellcome Postdoctoral Fellow, University of Exeter, UK

Q. What initially led you into academia?

A. My fascination with muscle physiology originated in 2007, when I had my leg cast for 7 weeks after a basketball injury. At the time I had to pick a dissertation topic for my BSc Nutrition and Health at Wageningen University (Netherlands). After being left with a very thin leg once the cast was removed, I decided to write a thesis about muscle disuse atrophy. Shortly after that I met Professor Luc van Loon at Maastricht University, whom I had approached for an MSc project, and he suggested to come over for a year to work on a study with spinal cord-injured individuals. Ever since stepping into the lab I knew I wanted to do a PhD, and I was delighted that several years later the opportunity came up. I find the fact that we can lose muscle mass so rapidly incredibly fascinating. As an example, a healthy individual who remains bed-rested for a week loses close to 1.5 kg of lean tissue, while it takes at least 8-10 weeks of progressive resistance training to gain a similar amount of muscle. Gaining insight into why we lose muscle during physical inactivity and how we can prevent this muscle loss is, to date, still the focus of my academic career.

Q. How did you hear about membership of The Physiological Society, how long have you been a member and what do you value most about your membership?

A. When I started as a postdoctoral fellow at the University of Exeter in 2016, my colleagues told me about the opportunities that membership of The Physiological Society would provide, and I signed up. There are various benefits of my membership that I value, including hearing about and taking part in the various meetings and workshops that are organised, the opportunities to apply for fellowships, and the support The Physiological Society provides to Society Representatives to organise institutional seminars or conferences. The Society contributes to physiology research, education and dissemination in many ways, and I appreciate that they are always open to input and suggestions.

Q. You were funded by The Physiological Society to conduct a project on the role of dietary branched-chain amino acid ingestion and omittance on skeletal muscle protein synthesis and insulin sensitivity. Why is this an important research question to investigate?

A. Despite a strong focus on the potential beneficial effects of branched-chain amino acids (BCAAs) on skeletal muscle mass in the field of muscle amino acid metabolism, their role in the stimulation of postprandial muscle protein synthesis remains to be elucidated. Importantly, the potentially anabolic effect of BCAAs may be overridden by their potential involvement in the development of muscle insulin resistance. In my Physiological Society Accelerator Fellowship, I am investigating whether BCAAs are required to stimulate muscle protein synthesis, and simultaneously examine the effect of dietary BCAA omittance on muscle insulin sensitivity. This will advance the field of physiology by providing insight into the mechanisms that underlie muscle mass maintenance and metabolic health, and specifically the role of BCAA therein. Moreover, I envisage that the data generated via this Accelerator Fellowship will act as the foundation for further work in insulin resistant populations, e.g. individuals with type 2 diabetes (in whom BCAA omittance or restriction might be a potential interventional strategy to attenuate muscle loss and improve metabolic health) or ICU patients (who have large quantities of exogenous amino acids coming from muscle protein breakdown, accompanied by the rapid development of severe insulin resistance).

Q. You are now roughly halfway through your project; how has the support helped your project move forward?

A. The funding by The Physiological Society has enabled the start of a new research line on the role of BCAAs in skeletal muscle protein turnover and metabolic health. Practically, this support has helped me in taking up a part-time position at Wageningen University in the Netherlands, in addition to my position at the University of Exeter. Importantly, the Society’s support has provided me with opportunities to expand my research team via the appointment of a PhD student and a research nurse, and new collaborations to establish the required mass spectrometry analyses. Although most progress at this stage has taken place behind the scenes, I am very pleased that the expansion of my research team will ensure that the study will start shortly, with the next generation of scientists benefiting from training on this project.

Q. How do you think receiving support from The Society has helped with your career development?

A. Being able to expand my research team has been a tremendous step for my career. Importantly, the PhD student starting on the project will provide me with the opportunity to take on the role of primary supervisor for the first time. Although I have had the opportunity to co-supervise several PhD students in the past, being able to take on the role of primary supervisor will be very important for my career development. Moreover, the 4 years of funding for the PhD student will enable them to follow up the results from this project with future work on skeletal muscle BCAA metabolism. As such, the support via the Accelerator Fellowship has not only supported me by providing funding for the first study of a new research line, but also follow-up work to develop this further. I am very grateful for the support from The Physiological Society and the opportunities it has provided, and am looking forward to being able to share the results from this support in the years to come!

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