Arrieta, M.-C. | Search bioRxiv

bioRxiv2020

Consumption of artificially sweetened beverages during pregnancy impacts infant gut microbiota and body mass index

Artificial sweetener consumption by pregnant women has been associated with an increased risk of infant obesity, but the underlying mechanisms are unknown. We aimed to determine if maternal consumption of artificially sweetened beverages (ASB) during pregnancy is associated with modifications of infant gut bacterial community composition during the first year of life, and whether these alterations are linked with infant body mass index (BMI) at one year of age. This research included 100 infants from the prospective Canadian CHILD Cohort Study, selected based on maternal ASB consumption during pregnancy (50 non-consumers and 50 daily consumers). We identified four microbiome clusters, of which two recapitulated the maturation trajectory of the infant gut bacterial communities from immature to mature and two deviated from this trajectory. Maternal ASB consumption was associated with the depletion of several Bacteroides sp. and higher infant BMI. As we face an unprecedented rise in childhood obesity, future studies should evaluate the causal role of gut microbiota in the association between maternal ASB consumption, infant development and metabolism, and body composition.

microbiology↗

bioRxiv2019

Contribution of fungal microbiome to intestinal physiology, early-life immune development and mucosal inflammation in mice

Gut microbiomes make major contributions to the physiological and immunological development of the host, but the relative importance of their bacterial and fungal components, and how they interact, remain largely unknown. We applied carefully controlled experiments in gnotobiotic mice colonized with defined communities of bacteria, fungi, or both to differentiate the direct role of fungi on microbiome assembly, host development, and susceptibility to colitis and airway inflammation. Our results revealed that fungal colonization alone was insufficient to promote the intestinal anatomic and physiological changes seen in mice colonized by bacteria, and had limited impact on the fecal metabolome. However, fungal colonization promoted major shifts in bacterial microbiome ecology, and had an independent effect on the innate and adaptive immune development in young mice. Fungi further exacerbated some aspects of the inflammatory effects of the bacterial community during OVA-induced airway inflammation by promoting macrophage infiltration in the airway. Our results demonstrate a dominant ecological and physiological role of bacteria in gut microbiomes, but highlight fungi as an ecological factor shaping the assembly of the bacterial community and a direct capacity to impact immune system and modulate disease susceptibility. These findings demonstrate that studies focused on bacteria alone provide an incomplete portrayal on microbiome ecology and functionality, and prompt for the inclusion of fungi in human microbiome studies.

microbiology↗