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

Olivia Raglan,Anita Mitra,David A Macintyre,Ann Smith,Maria Kyrgiou,Sanjay Purkayastha,Yun S Lee,Phillip R Bennett,Marc J Gunter,Hani Gabra,Nada Assi,Jaya Nautiyal,Julian R Marchesi

doi:10.1186/s40168-021-01011-2

Abstract

BackgroundObesity 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.MethodsVaginal 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.ResultsThe 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.ConclusionsObese 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.9Ths4NJW1qxph_9zeEV_5KVideo abstract

Highlights

Obesity and vaginal microbiome (VMB) dysbiosis are each risk factors for adverse reproductive and oncological health outcomes in women
We investigated how obesity, defined as body mass index (BMI) ≥30 kg/m2, associates with bacterial structure and composition of the vaginal microbiome compared to non-obese women and local inflammation
Obesity has been associated with a multitude of adverse health outcomes in women [2, 4, 5, 12, 18], and the mechanisms leading to these complications of obesity in women remain unclear, the vaginal microbiota composition may be important

Summary

Introduction

Obesity and vaginal microbiome (VMB) dysbiosis are each risk factors for adverse reproductive and oncological health outcomes in women. High-throughput sequencing approaches have aided characterisation of the vaginal microbiota in health and disease states, leading to a better understanding of the factors which affect vaginal community composition including age and ethnicity [31], menstrual cycle phase [32], oestrogen levels and menopause status [33], intercourse [34], pregnancy [35, 36] and hygiene practices [37]

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