The association between obesity and weight loss after bariatric surgery on the vaginal microbiota

Abstract

Background Obesity and vaginal microbiome (VMB) dysbiosis are each risk factors for adverse reproductive and oncological health outcomes in women. Here, we investigated the relationship between obesity, vaginal bacterial composition, local inflammation and bariatric surgery. Methods Vaginal bacterial composition assessed by high-throughput sequencing of bacterial 16S rRNA genes and local cytokine levels measured using a multiplexed Magnetic Luminex Screening Assay were compared between 67 obese and 42 non-obese women. We further assessed temporal changes in the microbiota and cytokines in a subset of 27 women who underwent bariatric surgery. Results The bacterial component of the vaginal microbiota in obese women was characterised by a lower prevalence of a Lactobacillus-dominant VMB and higher prevalence of a high diversity (Lactobacillus spp., and Gardnerella- spp. depleted) VMB, compared with non-obese subjects (p<0.001). Obese women had higher relative abundance of Dialister species (p<0.001), Anaerococcus vaginalis (p=0.021), and Prevotella timonensis (p=0.020) and decreased relative abundance of Lactobacillus crispatus (p=0.014). Local vaginal IL-1β, IL-4, IL-6, IL-8, IFNγ, MIP-1α and TNFα levels were all higher among obese women, however, only IL-1β and IL-8 correlated with VMB species diversity. In a subset of obese women undergoing bariatric surgery, there were no significant overall differences in VMB following surgery; however, 75% of these women remained obese at 6 months. Prior to surgery, there was no relationship between body mass index (BMI) and VMB structure; however, post-surgery women with a Lactobacillus-dominant VMB had a significantly lower BMI than those with a high diversity VMB. Conclusions Obese women have a significantly different vaginal microbiota composition with increased levels of local inflammation compared to non-obese women. Bariatric surgery does not change the VMB; however, those with the greatest weight loss 6-month post-surgery are most likely to have a Lactobacillus-dominant VMB.

The vaginal microbiome in women of reproductive age with healthy weight versus overweight/obesity

“…In addition, BV has also been associated with increased rates of sexually transmitted infections and pregnancy complications, including preterm birth (6,7,31). A recent study looked at Lactobacillus dominance in the vaginal microbiome among women with obesity following bariatric surgery and noted a significant increase in Lactobacillus dominance among women who experienced significant weight loss postsurgically (32).…”

The Intestinal Microbiome in Patients Undergoing Bariatric Surgery: A Systematic Review

“…The IM works as an organ of the human body, whose various functions can suffer alterations if not nourished correctly 14 , 16 , 17 . Its main activities are related to the immune system, helping in the intestinal barrier, metabolism, nutrient absorption, vitamin synthesis, defense against pathogens, and the dehydroxylation of bile acid.…”

“…Obese individuals often have the microbiota associated with a decrease in Bacteroidetes and an increase in Firmicutes , but some studies in humans have found an opposite ratio, suggesting that the Firmicutes-Bacteroidetes ratio would be increased. Low MGR in obese people is associated with metabolic diseases, inflammation, and insulin resistance 16 , 17 . IM may contribute to obesity in some ways.…”

“…Therefore, the Enterococcus species, for example, when fermenting dietary fiber, produce certain SCFAs that are directly related to the decrease in appetite. Thus, direct communication is established between gut and brain 1 , 3 , 4 , 12 , 15 – 17 .…”

“…Another effect of bariatric surgery, pointed out by studies, is the possible improvement of dysbiosis found in obese patients, which may lead to an increase in the diversity of the IM and the richness of microbial genes, in addition to an increase in specific genera of bacteria. Such changes lead to weight loss, reduced systemic inflammatory status, increased insulin sensitivity, and various metabolic improvements 17 .…”