Orally Administered Bifidobacterium adolescentis Diminishes Serum Glutamate Concentration in Mice

Abstract

This work presents the results of a trial using mice as a model that were fed with a bacterial strain of the species B. adolescentis , which possesses different active genes capable of degrading glutamate and converting it into GABA. Indeed, the bacterium is able to survive the passage through the gastric tract and, more importantly, the animals reduce over time the concentration of glutamate in their blood.

Mouse intestinal microbiome modulation by oral administration of a GABA-producing Bifidobacterium adolescentis strain

“…Since 16S rRNA regions sequenced do not permit to discriminate among Bifidobacterium species, we cannot rule out the possibility that other bifidobacterial species naturally encountered in the animals might be contributing to the high levels of Bifidobacterium detected in the control group or even to those detected in the vehicle group. However, our culture-dependent results did not reveal differences in the amount of viable absolute amount of bifidobacterial cells that can be recovered from both control and probiotic groups and confirm the absence of recoverable bifidobacterial cells in the vehicle group, which were beyond the detection limit (<10 2 CFU/mL) ( 30 ).…”

“…In this work, the administration of B. adolescentis strains, including the GABA producer IPLA 60004 previously characterized in our research group ( 29 , 30 ) to healthy mice, did result in a significant alteration in the representation of several microbial taxa at intestinal level. Administration of control strain (LMG10502 T ) resulted in an increased representation in the colonic contents of Faecalibaculum, and administration of GABA-producing strain (IPLA60004) resulted in an increased representation of Bifidobacterium , Lactobacilli , and Clostridia UCG-014, as compared to the groups receiving only the vehicle.…”

“…1 ). Besides, fecal samples plating at the beginning of the experiment demonstrated the absence of recoverable bifidobacterial cells, whereas along the intervention period (days 2–14), an average of 5.21 ± 0.38 and 5.15 ± 0.76 logarithmic CFU/mL of bifidobacterial cells was recovered in the control groups (male and female groups, respectively), and an average of 5.46 ± 0.65 and 5.29 ± 0.54 logarithmic CFU/mL of bifidobacterial cells was recovered in the probiotic groups (male and female groups, respectively) ( 30 ). No significant differences were detected in the level of recoverable viable bifidobacterial cells for the two bifidobacterial strains administered, LMG10502 T (control) and IPLA60004 (probiotic), neither between male and female groups.…”

“…In order to further investigate the possible modulation that the strains administration may have on the intestinal microbiome, a metataxonomic profiling of the gut microbiota was performed (longitudinally along the intervention, from fecal samples; and at the end of the experimental period, from individual colonic contents). Besides, target metabolites including short-chain fatty acids, GABA, and glutamate were determined in these samples and correlated to the data obtained from serum and brain tissues and included in a prior publication ( 30 ). When no differences were observed among male and female animals, data are presented jointly without animal’s segregation by sex.…”

“…All animal experimentation was conducted in accordance with Spanish guidelines for the care and use of laboratory animals, and protocols were approved by the CIC bioGUNE Institute and the regional Basque Country ethical committee (ref. P-CBG-CBBA-1521) as previously described, using sex-segregated groups ( 30 ). Briefly, C3H/HeJ mice were provided by the Jackson Laboratory (Bar Harbor, Ma, USA) at the age of 9 weeks.…”