Yellow Fellows: Is the gut microbiota changed in mild hyperbilirubinemia?

Autoren:Zöhrer, Patrick A.; Mölzer, Christine (University of Aberdeen); Wallner, Marlies (Fachhochschule Joanneum); Berry, David; Wagner, Karl-Heinz
Abstrakt:Modulations in bilirubin metabolism are phenotypically shown as moderately increased unconjugated bilirubin (UCB) levels. This condition of mild elevated UCB has been identified as inversely associated with the prevalence of cardiovascular diseases, type-2 diabetes as well as obesity. UCB levels above the commonly accepted threshold of 17.1 µM are the characteristic trait in Gilbert’s syndrome (GS), which affects approximately 10 percent of the Caucasian population. Furthermore, it is well established that the gut microbiota and its composition is linked to overall health, including body composition. The connection however, between bilirubin metabolism and the gut microbiota has not been evaluated so far. The aim of this project was therefore to discover links between UCB level, microbiota diversity and possible consequences on body composition. Based on the multiplex-barcoding-approach published previously, DNA was extracted from feces and the 16S-rRNA-gene sequence amplified. Subjects included age- and gender-matched BILIHEALTH study participants, divided into cases and controls based on a serum UCB cut-off of </≥17.1 µM (n = 45/45). Sequences were analyzed by an Illumina paired-end MiSeq-run and microbiota identified by comparative sequence analysis. Results showed effects of mildly increased UCB-levels (≥ 17.1 µM) on microbiota, primarily in individuals above 35 years of age (p = 0.008). However, age per se was found to contribute by trend to this change in microbial diversity (p = 0.057). Both factors favor a higher level of diversity. In addition, indicator species that were identified in this project to correlate with increased UCB levels are also the ones that are known as beneficial for health and body composition.