The Vaginal Microbiome: Disease, Genetics and the Environment

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DESCRIPTION: The vagina is an interactive interface with the environment, and as such is covered by a protective epithelial surface. This surface, in turn, is colonized by bacteria and other microorganisms which, through a variety of mechanisms serve to further protect the host from invasion by pathogens. Alterations in the normal vaginal microflora, particularly those associated with bacterial vaginosis, are thought to contribute to risk of spontaneous pregnancy loss in the second trimester and spontaneous preterm birth. Additionally, alterations in the vaginal microbiome may increase the likelihood of transmission of certain agents including human immunodeficiency virus type 1 (HIV-1). There are physiologic alterations in host condition (e.g., menopause and pregnancy), which are beginning to be investigated as potential selective conditions for change in the "normal" flora, and their impact on disease susceptibility and transmission remains to be more definitively elucidated. The effects of chronically abnormal physiologic states (e.g., diabetes mellitus) on normal vaginal flora have not been well described or studied. Finally, an almost unexplored area of inquiry is the genetic contribution, including race/ethnicity, to the establishment and maintenance of a "normal" vaginal flora, under normal and physiologically altered circumstances. The proposed research will address gaps in our knowledge and shed light on how the vaginal microbiome contributes to adverse obstetrical outcomes and sexually transmitted disease in diverse populations. The aims of the project are intended to answer the following questions: Specific Aim 1. Do the genes of the host contribute to the composition of the vaginal microbiome? We hypothesize that a woman's genetic composition significantly affects the ability of certain commensal, parasitic and pathogenic microbes to colonize and/or infect the genital tract. This aim is divided into 2 subaims, the first of which will compare and quantify the microbial populations inhabiting the vaginas of monozygotic (MZ) and dizygotic (DZ) twins in the Mid Atlantic Twin Registry (MATR). The second subaim will address the question of whether there is a relationship between the microbiomes of the vagina, mouth and GI tract utilizing samples collected from the DZ and MZ twins. Specific Aim 2. What changes in the vaginal microbiome are associated with common physiological perturbations or non-infectious pathological states of the host? We hypothesize that "altered" physiologic (pregnancy, menopause) and pathologic (chronic disease, hysterectomy) conditions, or environmental "exposures" (exogenous hormones, antibiotics, chronic immunosuppressant, smoking; douching) can and often do predictably alter the vaginal microenvironment. These alterations in turn will lead to alterations in microbial populations within the vagina. Changes in the microbial populations may have impacts, positive or more likely negative, on the spontaneous and future well-being of the affected individual. We will characterize the effects of these "altered" physiologic and pathologic conditions, and environmental exposures exert on the composition of the vaginal microbiome, and test the hypothesis that they lead to predictable changes in the vaginal microbiome. The relationship between the molecular analysis of the microbiome and laboratory findings based on Amsel's criteria and the Nugent Score will be evaluated. Specific Aim 3. What changes in the vaginal microbiome are associated with relevant infectious diseases and conditions? We will test the hypothesis that infectious diseases predictably alter the vaginal microbiome, and that these changes have an impact on the disease process. We will also test the hypothesis that the vaginal microbiome has an impact on susceptibility to some relevant infectious diseases. The research to be conducted in this Specific Aim will provide a platform for modeling the impact of physiological, pathological, environmental and ethnic/racial factors, and their interactions, in determining the vaginal microbiome. In addition to providing critical descriptive data, this will be a hypothesis-generating Specific Aim. We will analyze the vaginal microbiomes of: normal women of reproductive age; women in the same age range with common pathological conditions (e.g., vaginosis, vaginitis, viral infections, bacterial STDs); women of three different ethnic/racial groups: European Caucasian, African-American, and Mexican Hispanic. We will address these questions using a combination of high throughput 'nextgen' sequencing technologies, including the Roche 454 FLX and the upgraded Illumina Genome Analyzer II instruments currently installed in the Nucleic Acids Research Facilities at VCU.