Malon Van Den Hof Promoted After Outstanding PhD Defense

On November 19, Malon Van den Hof successfully defended her PhD “Growing up with HIV: Research into brain development and long-term health” in the Agnietenkapel in Amsterdam. She presented in front of family, friends, jury, her promoter Prof. Dr. Peter Reiss and co-promotors Dr. Dasja Pajkrt and Dr. Ferdinand Wit.

After completing year 1 of biomedical sciences at the University of Amsterdam (UvA), Malon pursued her studies in medicine. After receiving her medical degree where she participated in the honours program, Malon worked as a pediatric clinician for two years at the OLVG. Malon was attracted to the fields of infectious disease, global health, and tropical disease and under the motto of “always wanting to know the ins and outs of things”, she decided to pursue a research pathway. She started her PhD at the Amsterdam Medical Centre (AMC) in 2016 under supervision of Prof. Dr. Peter Reiss. The AMC is one of the four treatment centers for HIV-infected children.

A Unique Study

Malon’s 5-year study investigated brain development in children born with HIV. She observed brain functioning on two levels: on a structural level using MRI scans and on a cognitive functioning level. Malon compared two groups of children; children who are HIV-positive and children who are HIV-negative between the ages of 12 and 18. The control group was highly specific, exhibiting similar age, gender, ethnicity, and adoption history to the HIV-positive cohort, limiting bias. The results of her research suggest that the observed difference in brain development between children who are HIV-positive at birth and children who are HIV-negative at birth is already observable at baseline, and that the pace of development evolves similarly in the two groups.

Most MRI studies are cross-sectional studies and measure brain characteristics at one point in time. Malon observed the brain at two points in time at baseline and after a 5-year follow up. The longitudinal character of her study provides insights as to how brain development evolves in children infected with HIV over time. Malon discovered that the executive planning stage was an outlier in the trends, demonstrating that tasks such as planning, organizing, or working towards a certain goal were more impacted in the HIV-positive group. The fruits of her research show that more attention must be given in the executive functioning stage during development of children who are HIV-positive. She highlights the importance of HIV prevention by stressing treatment of women with HIV at an early stage of pregnancy, lowering the probability of giving birth to a child who is HIV-positive to less than 1%. It all comes down to integrating preventive practices, with testing and monitoring at an early stage of pregnancy.

What’s next for Malon?

There is still a lot to learn from her generated data, and she is looking forward to seeing what the data brings to PhD successors. Malon has published 5 articles as part of her PhD, and two are currently under finalization. She hopes that there will be funding in the future to follow-up on this research and observe brain development over longer periods of time. Malon plans to continue research, focusing on the impact of early life adversities – particularly in the first 1000 days of life – on health later life. She will alternate this with the role of prevention-focused youth healthcare doctor at municipality level. Though working virtually only minorly impacted her PhD, the current pandemic will impact her post-doctoral work more heavily because the institutions she collaborates with are closed and work from home. We wish Malon the best of luck in her future endeavors and congratulate her on her doctorate!