Vaginal Histological Changes Of The Baboon During The Normal Menstrual Cycle And Pregnancy

Nyachieo, Atunga; Kiulia, NM; Arimi, MM; Chai, Daniel; Jm, Mwenda

doi:10.4314/eamj.v86i4.46946

Cited by 6 publications

(8 citation statements)

References 14 publications

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“…The histological and cytological changes of the vagina during the menstrual cycle are similar in humans and baboons33, including an increased level of glycogen-enriched cells during ovulation3334. Differences in the structural morphology of the vagina include epithelial maturation (which occurs in the early proliferative phase in baboons but the ovulation phase in humans), the absence of erythrocytes in the vaginal smear around ovulation35 and the presence of cornification of the vaginal epithelium in 10% of baboon specimens36; in humans, hyperkeratosis represents a metaplastic change37.…”

Section: Discussionmentioning

confidence: 87%

Vaginal Dysbiosis from an Evolutionary Perspective

Schlabritz‐Loutsevitch

Gygax

Dick

et al. 2016

Sci Rep

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Evolutionary approaches are powerful tools for understanding human disorders. The composition of vaginal microbiome is important for reproductive success and has not yet been characterized in the contexts of social structure and vaginal pathology in non-human primates (NHPs). We investigated vaginal size, vulvovaginal pathology and the presence of the main human subtypes of Lactobacillus spp./ BV-related species in the vaginal microflora of baboons (Papio spp.). We performed morphometric measurements of external and internal genitalia (group I, n = 47), analyzed pathology records of animals from 1999–2015 (group II, n = 64 from a total of 12,776), and evaluated vaginal swabs using polymerase chain reaction (PCR) (group III, n = 14). A total of 68 lesions were identified in 64 baboons. Lactobacillus iners, Gardnerella vaginalis, Atopobium vaginae, Megasphaera I, and Megasphaera II were not detected. L. jensenii, L. crispatus, and L. gasseri were detected in 2/14 (14.2%), 1/14 (7.1%), and 1/14 (7.1%) samples, respectively. BVAB2 was detected in 5/14 (35.7%) samples. The differences in the vaginal milieu between NHP and humans might be the factor associated with human-specific pattern of placental development and should be taken in consideration in NHP models of human pharmacology and microbiology.

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Section: Discussionmentioning

confidence: 87%

Vaginal Dysbiosis from an Evolutionary Perspective

Schlabritz‐Loutsevitch

Gygax

Dick

et al. 2016

Sci Rep

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“…Specifically, rising estrogen levels increase available glycogen in the vaginal epithelium, which in turn, provides an energy source for lactobacilli to produce lactic acid. Indeed, like humans, many non-human mammals exhibit a thickening of the vaginal epithelium and increasing glycogen content in response to rising estrogen levels during the ovarian cycle (e.g., Gregoire and Guinness, 1968; Gregoire and Parakkal, 1972; Williams et al, 1992; Nyachieo et al, 2009). However, direct correlations between estrogen, glycogen, lactic acid, lactobacilli, and vaginal pH have yet to be explored in non-human mammals to the extent they have been in humans (e.g., Boskey et al, 1999, 2001; Mirmonsef et al, 2014; but see Mirmonsef et al, 2012).…”

Section: Resultsmentioning

confidence: 99%

Lactobacilli Dominance and Vaginal pH: Why Is the Human Vaginal Microbiome Unique?

et al. 2016

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The human vaginal microbiome is dominated by bacteria from the genus Lactobacillus, which create an acidic environment thought to protect women against sexually transmitted pathogens and opportunistic infections. Strikingly, lactobacilli dominance appears to be unique to humans; while the relative abundance of lactobacilli in the human vagina is typically >70%, in other mammals lactobacilli rarely comprise more than 1% of vaginal microbiota. Several hypotheses have been proposed to explain humans' unique vaginal microbiota, including humans' distinct reproductive physiology, high risk of STDs, and high risk of microbial complications linked to pregnancy and birth. Here, we test these hypotheses using comparative data on vaginal pH and the relative abundance of lactobacilli in 26 mammalian species and 50 studies (N = 21 mammals for pH and 14 mammals for lactobacilli relative abundance). We found that non-human mammals, like humans, exhibit the lowest vaginal pH during the period of highest estrogen. However, the vaginal pH of non-human mammals is never as low as is typical for humans (median vaginal pH in humans = 4.5; range of pH across all 21 non-human mammals = 5.4–7.8). Contrary to disease and obstetric risk hypotheses, we found no significant relationship between vaginal pH or lactobacilli relative abundance and multiple metrics of STD or birth injury risk (P-values ranged from 0.13 to 0.99). Given the lack of evidence for these hypotheses, we discuss two alternative explanations: the common function hypothesis and a novel hypothesis related to the diet of agricultural humans. Specifically, with regard to diet we propose that high levels of starch in human diets have led to increased levels of glycogen in the vaginal tract, which, in turn, promotes the proliferation of lactobacilli. If true, human diet may have paved the way for a novel, protective microbiome in human vaginal tracts. Overall, our results highlight the need for continuing research on non-human vaginal microbial communities and the importance of investigating both the physiological mechanisms and the broad evolutionary processes underlying human lactobacilli dominance.

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“…4b), we also used LEfSe to identify the microbial taxa that exhibited the greatest changes in relative abundance during periovulation or anestrus relative to other cycle phases. These two phases may exhibit particularly distinct microbial communities because they represent the periods of maximum and minimum estrogen and vaginal glycogen within the ovarian cycle [46, 50–52]. Overall, samples from periovulatory females exhibited significantly higher relative abundance of Bacilli , especially members of the lactic acid-producing order Lactobacillales (mean: 44 ± 10% SD), and significantly lower relative abundance of the family Fusobacteriaceae , as compared to the other three cycle phases (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Similar to humans, we found that reproductive state is also the primary driver of inter-individual variation in baboon vaginal microbiota, and many of the patterns we observe are consistent with the idea that fluctuations in estrogen and glycogen drive baboon vaginal microbial dynamics. For instance, like humans, glycogen is lowest in baboon vaginal mucus during both pregnancy and postpartum amenorrhea and highest during ovarian cycling [52]. Paralleling this pattern, the family Aerococcaceae , particularly the genus Facklamia , is prolific during pregnancy and PPA in female baboons, but rare during ovarian cycling.…”

Section: Discussionmentioning

confidence: 98%

“…However, like humans, baboons reproduce year-round: when not pregnant or in postpartum amenorrhea, baboons experience ~34-day ovarian cycles and can conceive at any time of the year [48, 49]. Also similar to humans, estrogen and vaginal glycogen are highest in baboons around ovulation and decrease during anestrus (i.e., menses)[46, 50–52]. Hence, if baboon vaginal microbiota experience dynamics similar to those in humans, we would expect to observe relatively high levels of lactic acid-producing bacteria during the periovulatory period and relatively low levels during low estrogen periods such as anestrus.

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Section: Introductionmentioning

confidence: 99%

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Ovarian cycling and reproductive state shape the vaginal microbiota in wild baboons

et al. 2017

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BackgroundThe vaginal microbiome is an important site of bacterial-mammalian symbiosis. This symbiosis is currently best characterized for humans, where lactobacilli dominate the microbial community and may help defend women against infectious disease. However, lactobacilli do not dominate the vaginal microbiota of any other mammal studied to date, raising key questions about the forces that shape the vaginal microbiome in non-human mammals.ResultsWe used Illumina sequencing of the bacterial 16S rRNA gene to investigate variation in the taxonomic composition of the vaginal microbiota in 48 baboons (Papio cynocephalus), members of a well-studied wild population in Kenya. Similar to prior studies, we found that the baboon vaginal microbiota was not dominated by lactobacilli. Despite this difference, and similar to humans, reproductive state was the dominant predictor of baboon vaginal microbiota, with pregnancy, postpartum amenorrhea, and ovarian cycling explaining 18% of the variance in community composition. Furthermore, among cycling females, a striking 39% of variance in community composition was explained by ovarian cycle phase, with an especially distinctive microbial community around ovulation. Periovulatory females exhibited the highest relative abundance of lactic acid-producing bacteria compared to any other phase, with a mean relative abundance of 44%. To a lesser extent, sexual behavior, especially a history of shared sexual partners, also predicted vaginal microbial similarity between baboons.ConclusionsDespite striking differences in their dominant microbes, both human and baboon vaginal microbiota exhibit profound changes in composition in response to reproductive state, ovarian cycle phase, and sexual behavior. We found major shifts in composition during ovulation, which may have implications for disease risk and conception success. These findings highlight the need for future studies to account for fine-scale differences in reproductive state, particularly differences between the various phases of the ovarian cycle. Overall, our work contributes to an emerging understanding of the forces that explain intra- and inter-individual variation in the mammalian vaginal microbiome, with particular emphasis on its role in host health and disease risk.Electronic supplementary materialThe online version of this article (doi:10.1186/s40168-017-0228-z) contains supplementary material, which is available to authorized users.

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Vaginal Histological Changes Of The Baboon During The Normal Menstrual Cycle And Pregnancy

Cited by 6 publications

References 14 publications

Vaginal Dysbiosis from an Evolutionary Perspective

Vaginal Dysbiosis from an Evolutionary Perspective

Lactobacilli Dominance and Vaginal pH: Why Is the Human Vaginal Microbiome Unique?

Ovarian cycling and reproductive state shape the vaginal microbiota in wild baboons

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