The role of Blastocystis in inflammatory bowel disease.

Når folk lider av alvorlige tarmproblemer, undersøker sykehuset ofte pasientens avføring for å se etter ledetråder. Hvis sykehuslaboratoriet finner små organismer kalt mikrobielle eukaryoter, antas de ofte å være årsaken til sykdommen og pasienten får medisiner for å eliminere disse parasittene. Dette forskningsprosjektet fokuserer på en slik parasitt kalt Blastocystis fordi vi er i tvil om det faktisk er en parasitt. Tidligere studier med undersøkelser gjort i mindre grupper av mennesker har funnet denne "parasitten" hos en stor andel av mennesker uten tarmproblemer. Dessuten, når vi gir denne parasitten til rotter som har alvorlig tarmsykdom, er symptomene mindre alvorlige sammenlignet med rotter som ikke har fått Blastocystis.

When people suffer from severe intestinal problems, the hospital often examines the patient's stool to look for clues. If the hospital lab finds small organisms called microbial eukaryotes, they are often thought to be the cause of the disease and the patient is given medication to eliminate these parasites. This proposal focuses on one such parasite called Blastocystis because we have doubts about whether it is actually a parasite. Previous studies using small groups of people have found this ‘parasite’ in a large proportion of people without intestinal problems. Also, when we give this parasite to rats that have severe intestinal disease, symptoms are less severe compared to rats that have not been given Blastocystis. To prevent people being treated for something that did not make them sick, we want to investigate this matter thoroughly. We will be looking for the distribution of Blastocystis in a large Danish study group that includes over 7,000 people. This background population will be the largest study of the distribution of Blastocystis ever. We will also be looking for Blastocystis in a large 700 patient Norwegian clinical trial of inflammatory bowel disease. We will also try to find out whether cancer patients receiving immunotherapy are more or less likely to develop severe bowel disease (as an adverse side effect) if they have Blastocystis or not. Finally, we will conduct comparative studies in a rat model that we can infect with Blastocystis and then induce bowel disease, as this will allow us to study in a controlled manner whether Blastocystis makes symptoms better or worse. We hope that our thorough investigations with a large interdisciplinary team of clinicians, molecular biologists, epidemiologists, and animal scientists will eventually allow us to inform hospitals whether they should treat patients when they find Blastocystis or whether they need to look further for the real cause of the patients' symptoms.