28 April Thesis defense Jelte van der Vaart: “Modelling of a wide variety of disease using adult stem cell-derived organoids.” Back to news Jelte van der Vaart, member of the group of Hans Clevers, successfully defended his PhD thesis “Modelling of a wide variety of disease using adult stem cell-derived organoids” on the 28th of April 2022. His research focused on the mechanisms behind a variety of human diseases by using miniature organs in a dish: organoids. During his PhD, Van der Vaart used several organoid models to gain a better understanding of various diseases related to the airways, intestines and thyroid gland. According to the researcher, these models can speed up the process of implementing scientific findings in the clinic. To reduce the need for laboratory animals or human patient material, organoidsMiniature organs that can be cultured in the laboratory. These organoids mimic the shape and function of the original organ in the body. Researchers use these structures to, for example, study the effects of medication on diseased organs. are widely used in research. This development opened up a possibility to study the functioning of organs, both healthy and diseased, in the laboratory. For this purpose, Jelte van der Vaart used various existing organoid models to study divergent human diseases. Furthermore, he developed new organoid systems of human alveoli to study SARS-CoV-2 infection of the lower airways. He also cultivated organoids of the thyroid gland, which can be used to study Graves’ disease. The research on all of these models generated a lot of data, which provides a better view on mechanisms behind various human diseases. SARS-CoV-2 research during the pandemic One of the highlights of Van der Vaart’s PhD was the study on SARS-CoV-2. Together with Joep Beumer, he collected the required virus samples at the Erasmus MC in Rotterdam. During the national lockdown, the two travelled over empty roads to do their experiments in an empty institute. Van der Vaart: “It felt apocalyptic and like any end-of-the-world series: two scientists were trying to find a cure to save the world. A published manuscript in Science as a result also helps the good memory.” In this publication, the researchers provided evidence that SARS-CoV-2 could infect intestinal cells. This gave new perspectives on the spreading and infectious properties of the virus. Future perspectives Since the organoid models are representative of human organs, processes observed in these models are representative for processes in the human body. This makes the translation of scientific findings to the clinic easier. Ultimately, this could speed up the bench-to-bedside process for new therapeutics for the studied diseases. Furthermore, the thyroid gland organoids that Van der Vaart developed are an innovation in organoid biology. These create the possibility to study both the healthy and diseased thyroid gland in the future. According to Van der Vaart, his research is only the tip of the iceberg of understanding human biology and disease: “The next steps would require experts in diverse scientific fields, including virology, (stem) cell biology and the clinic. They have to apply these organoids for outstanding questions in their fields.” The importance of balance Standing at the end of his own PhD, Van der Vaart recommends other PhD students to find the balance between their project and personal life. “While a PhD might seem super stressful, try to find your joy in the project but also outside of the lab. It is better to be efficient when you are in the lab and have some activities to relax again in weekends and evenings, than to spend every waking hour in the lab. By taking your mind off your experiments, you will actually come up with new ideas and feel lively to undertake those ideas.” Time to celebrate Since the restrictions on gatherings are lifted, Van der Vaart can fully celebrate obtaining his PhD: “I will have a full audience during the defense, as well as during the drinks afterwards. The next day, we will have a big party to celebrate with friends and family!” In February, Van der Vaart started his postdoc in the group of Madelon Maurice at the UMC Utrecht. He will be working on developing organoid models to study the Peutz-Jeghers syndrome and adrenal cortical cancer.