PhD defence S.Y. (Suk) Lam

Technical advances in the field of microbial research have enabled the in depth investigation of the microorganisms within the gastrointestinal tract and their genetic content (microbiome). It has become apparent that the bacteria within our human body play an important role in health, but also the development of diseases. Nowadays, not only diseases of the intestinal tract, but also metabolic disorders, skin diseases and psychiatric disorders have been linked to changes of the gut microbiota. To investigate the role of bacterial compositional changes relevant in different diseases, it is important to better understand the normal microbiome. Therefore, we investigated the bacterial composition along the gastrointestinal tract using a special technique (16S rRNA amplicon sequencing) and showed that the density and composition of the upper and lower parts of the gastrointestinal tract differ. We have also indicated that the application of this technique is challenging to investigate tissue fragments preserved in paraffin blocks, but illustrated that targeted analysis of specific bacteria was possible in this material as well as in samples used in the national colorectal cancer screening program (fecal immunochemical test). We further investigated whether microbiome analysis could play a role in the prediction of colorectal cancer, relapse of inflammatory bowel disease following surgery, and the skin disease ‘hidradenitis suppurativa, where we observed specific bacterial differences in patients and controls. Lastly, we demonstrated that variation in the human genetic code may influence how the human body handles bacterial Helicobacter pylori infection of the stomach.

The public defence will take place at the Prof. Andries Queridoroom, 3rd floor Education Center, location Erasmus MC. The ceremony will begin exactly at 10.30 AM. In light of the solemn nature of the ceremony, we recommend that you do not take children under the age of 6 to the first part of the ceremony.