The work performed and the main results: In order to identify the timing of the effect of microbiota on lung development (Objective 1), I setup a larger and repeat experiment to elucidate effect the probiotic exposure of Dams through pregnancy and weaning periods. I added a cross-breeding element, by redistributing pups at birth between dams, in such a way that I would end up with four groups of offspring with different timing of exposure to Dams microbiome with and without probiotic bacteria. (1.PRO-PRO 2.PRO-Control 3.Control-PRO and 4.Control-Control). I measured lung physiology by stereology and breathing patterns of these four groups of offspring. The results show that breathing patterns are indeed influenced by timing of exposure but was unable to repeat the physiological changes by stereology results from the preliminary experiments.
In order to identify the mechanism behind the effect of microbiota on lung development (Objective 2), I performed microbiota transfer experiment, where pregnant mice completely free of bacteria (Germ-free(GF)), were exposed to become: either Controls (no exposure), Monoculture (exposed to the single probiotics strain of Bifidobacteria) or Full Microbiome (exposed to a full microbiome composition from Dams used in Objective 1). The offspring of these dams was then tested for, milk microbiome and milk components of the Dams, lung-gene-expression and specific immunesystem alterations of the offspring at age of 10days (when they are still obligatory fed by mothers milk) and breathing patterns age of 21 days. Results so far, shows small changes to the immunesystem, gene expression and breathing patterns according to the direct exposure of the dams and indirect though milk and housing in early life. Furthermore, we are currently mapping fluctuations to the pregnancy gut microbiome of the dams according to exposure throughout the pregnancy period. These data and the milk analysis are still being compiled.
The final objective (Objective 3) was to apply the result to a relevant lung disease model of BPD based on O2 exposure. This was never attempted, as some of the questions were simultaneously addressed and published by my research collaborators and leading scientists at The University of Michigan. Their results show that the microbiome indeed are influenced by O2 exposure and has an influence on lung damage in BPD in correlations to the lung microbiome of the mice.
