The findings once again highlight the role the gut microbiome plays in controlling nutrient absorption as well as reducing the factors that contribute to persistent inflammation.
Metabolic disorders, such as obesity and type 2 diabetes, are associated with a state of chronic, low-grade inflammation in peripheral tissues as well as the circulation.
This inflammation can affect multiple tissues and organs, including the liver, skeletal muscle and heart, which can lead to various chronically painful conditions, such as osteoarthritis.
The study could lead to improvements in treating the inflammatory state of the gut and adipose tissue. The hope is to better understand a possible mechanism underlying the anti-obesity effect of the probiotic mix studied.
The University of Toulouse researchers took a probiotic mixture that consisted of five bacterial strains (Lactobacillus acidophilus, L. plantarum, L. salivarius and two strains of Bifidobacterium lactis).
They wanted to see if the inclusion of this mixture into the diet of mice could weaken the onset of obesity induced by a high-fat diet.
The probiotic mixture had been the subject of a previous study that demonstrated its anti-inflammatory properties.
In addition, the mixture has also shown efficacy in preventing disruption of the gut epithelial barrier in a similar study. Here researchers demonstrated that another probiotic mix could protect the epithelial barrier from the disruption caused by stress and prevent intestinal hypersensitivity found in Irritable Bowel Syndrome patients.
Twenty-seven male mice aged 6 weeks were randomly allocated to receive one of three different experimental diets for 14 weeks. These diets were the control (CT), a high-fat (HF) diet and a HF diet plus the probiotic mixture (HF-Pb diet).
Body weights were recorded in all three groups of mice once a week. Body fat percentage was also measured at week 13.
Blood samples were also taken after a 6-h fast (before allocation to the experimental diets) and at weeks 6 and 12. Serum glucose and insulin concentrations were determined from this.
The researchers discovered that body weight increased to a greater extent in mice fed the high-fat diet than in those consuming the control diet, the difference between these two groups being significant from 6 weeks onwards.
However, the body weight increase induced by the high-fat diet was reduced by administration of the probiotic mixture, the difference between the HF and HF-Pb groups being significant from week 10 to the end of the study at week 14.
Mean serum glucose and insulin concentrations determined at week 12 were significantly higher in the HF and HF-Pb groups than in the CT group, but significantly lower (by 17 and 37%, respectively) in the HF-Pb group compared to the HF group.
“In this study, administration of this probiotic mixture for 14 weeks to mice fed a high-fat diet diminished the increase in body weight gain and body fat mass observed in mice receiving the same high-fat diet alone,” the study noted.
“It also protected mice from the insulin resistance induced by the high-fat diet as determined in the HF and HF-Pb groups.”
The study also identified a series of genes that have been implicated in inflammatory processes in the gut.
Analysis of these genes revealed an impact of the tested probiotic mixture on the expression of genes encoding unique enzymes found in the leukotriene pathway.
The Treg genes were also implicated in colon tissue from mice fed a high-fat diet. Here, the probiotic mixture increased the expression of genes involved in the immunosuppression and resolution of inflammation.
Previous data using experimental models and in clinical studies have already shown that changing the gut microbiota by means of prebiotics (such as fructans) or probiotics (such as Lactobacillus casei W8) may contribute to regulating gut peptide creation and controlling food intake.
With these results in mind the beneficial effect of this study’s probiotic mixture on body weight gain might be better understood by reducing food intake and/or increased energy expenditure.
Published online ahead of print, http://dx.doi.org/10.1016/j.phanu.2015.03.003
“A multispecies Lactobacillus- and Bifidobacterium-containing probiotic mixture attenuates body weight gain and insulin resistance after a short-term challenge with a high-fat diet in C57/BL6J mice.”
Authors: Sophie Holowacz, Charlotte Guigne´, Gerald Chene, Sandrine Mouysset, Angele Guilbot, Christian Seyrig, Marc Dubourdeau