Diet change affects intestinal microbiota restoration and improves vertical sleeve gastrectomy outcome in diet-induced obese rats - PubMed (original) (raw)
Diet change affects intestinal microbiota restoration and improves vertical sleeve gastrectomy outcome in diet-induced obese rats
Joana Rossell et al. Eur J Nutr. 2020 Dec.
Abstract
Purpose: Obesity, a worldwide health problem, is linked to an abnormal gut microbiota and is currently most effectively treated by bariatric surgery. Our aim was to characterize the microbiota of high-fat fed Sprague-Dawley rats when subjected to bariatric surgery (i.e., vertical sleeve gastrectomy) and posterior refeeding with either a high-fat or control diet. We hypothesized that bariatric surgery followed by the control diet was more effective in reverting the microbiota modifications caused by the high-fat diet when compared to either of the two factors alone.
Methods: Using next-generation sequencing of ribosomal RNA amplicons, we analyzed and compared the composition of the cecal microbiota after vertical sleeve gastrectomy with control groups representing non-operated rats, control fed, high-fat fed, and post-operative diet-switched animals. Rats were fed either a high-fat or control low-fat diet and were separated into three comparison groups after eight weeks comprising no surgery, sham surgery, and vertical sleeve gastrectomy. Half of the rats were then moved from the HFD to the control diet. Using next-generation sequencing of ribosomal RNA amplicons, we analyzed the composition of the cecal microbiota of rats allocated to the vertical sleeve gastrectomy group and compared it to that of the non-surgical, control fed, high-fat fed, and post-operative diet-switched groups. Additionally, we correlated different biological parameters with the genera exhibiting the highest variation in abundance between the groups.
Results: The high-fat diet was the strongest driver of altered taxonomic composition, relative microbial abundance, and diversity in the cecum. These effects were partially reversed in the diet-switched cohort, especially when combined with sleeve gastrectomy, resulting in increased diversity and shifting relative abundances. Several highly-affected genera were correlated with obesity-related parameters.
Conclusions: The dysbiotic state caused by high-fat diet was improved by the change to the lower fat, higher fiber control diet. Bariatric surgery contributed significantly and additively to the diet in restoring microbiome diversity and complexity. These results highlight the importance of dietary intervention following bariatric surgery for improved restoration of cecal diversity, as neither surgery nor change of diet alone had the same effects as when combined.
Keywords: Bariatric surgery; High-fat diet; Microbiota; Rat models.
Conflict of interest statement
On behalf of all authors, the corresponding author states that there is no conflict of interest.
Figures
Fig. 1
Experiment design and group distribution. Rats were fed either the control diet (red line) or HFD (blue line) for 8 weeks. At week eight, each diet group was then divided in three (n = 6), and subjected to one of the three surgical situations: No Surgery, Sham surgery or VSG. Half of the HFD-fed rats were then switched to the control diet (green line). Rats continued the allocated diet until week 12
Fig. 2
a The D group had a higher body weight gain from week one (P < 0.001). At week eight, half of the D animals switched from the HFD to the control diet, and all were divided into surgery groups NS, Sham or VSG. At week 12, VSG had a significantly lower BWG than Sham or NS in the same diet group, especially for D + C (P < 0.001). b Different parameters at week 12. The adiposity index was lowered by the combination of VSG and diet switch. Leptin was affected by VSG. Ghrelin was reduced in D groups. Insulin Sensitivity Index increased in D + C-VSG. No significant changes were seen in Insulin or HOMA-IR. P values < 0.001 (***) and a–c correspond for significantly different groups (Tukey post-test)
Fig. 3
Diversity measures. a Shannon and Simpson indices showing sample alpha diversity. The bottom and top of the boxplot indicate the first and third quartile, whilst the line inside the box show the median. Diversity was reduced by both Sham surgery and VSG in all groups. D samples had the lowest diversity except for D + C-NS in the NS situation. P values < 0.001 (***), P values < 0.01 (**) and a–c correspond for significantly different groups (Tukey post-test). b Beta diversity. The non-metric Multidimensinal Scaling (NMDS) plot for the bacterial communities in our samples based on Bray–Curtis dissimilarities. D groups, C-NS and C-VSG formed distinct clusters. PERMANOVA analysis: Surgery (P < 0.001), Diet (P < 0.001). D + C samples formed less defined clusters, but were very distinct from D samples and were overlapping the C-VSG and C-Sham groups
Fig. 4
Relative abundances of bacterial composition, a at the phylum level, dominated by the Bacteroidetes and the Firmicutes phyla. Relative abundances of bacterial composition, b at the family level, with phyla separations marked with black lines and family separations marked with white lines. Family names in legend grouped by phyla (phylums initial letter). Group labels were marked according the diet: Red for C, Blue for D, Green for D + C
Fig. 5
Graphic representation of the Spearman correlation coefficients between the significantly altered genera obtained by DESeq and different parameters such as adiposity index, biochemical parameters, and KEGG pathways. Positive correlations are shown in green color and negative correlations in red color. The color intensity and the circle size are proportional to the correlation coefficients. Only genera with significant correlations (< 0.05) are shown