Interindividual variation, correlations, and sex-related differences in the salivary biochemistry of young healthy adults.

A cross-sectional observational study was conducted to evaluate interindividual biochemical variation in unstimulated whole saliva in a population of 268 systemically healthy young students, 18-30 yr of age, with no apparent caries lesions or periodontal disease. Salivary flow rate, protein content, pH, buffering capacity, mucins MUC5B and MUC7, albumin, secretory IgA, cystatin S, lactoferrin, chitinase, amylase, lysozyme, and proteases were measured using ELISAs and enzymatic activity assays. Significant differences were found between male and female subjects. Salivary pH, buffering capacity, protein content, MUC5B, secretory IgA, and chitinase activity were all lower in female subjects compared with male subjects, whereas MUC7 and lysozyme activity were higher in female subjects. There was no significant difference between sexes in salivary flow rate, albumin, cystatin S, amylase, and protease activity. Principal component analysis (PCA) and spectral clustering (SC) were used to assess intervariable relationships within the data set and to identify subgroups. Spectral clustering identified two clusters of participants, which were subsequently described. This study provides a comprehensive overview of the distribution and inter-relations of a set of important salivary biochemical variables in a systemically healthy young adult population, free of apparent caries lesions and periodontal disease. It highlights significant gender differences in salivary biochemistry.

The impact of hormonal contraception and pregnancy on sexually transmitted infections and on cervicovaginal microbiota in african sex workers.

BACKGROUND: The observed association between Depo-Provera injectable use and increased HIV acquisition may be caused by hormone-induced increased susceptibility to other sexually transmitted infections (STIs) or changes in the cervicovaginal microbiota (VMB), accompanied by genital immune activation and/or mucosal remodeling. METHODS: Rwandan female sex workers (n = 800) were interviewed about contraceptive use and sexual behavior and were tested for STIs, bacterial vaginosis by Nugent score and pregnancy, at baseline. A subset of 397 HIV-negative, nonpregnant women were interviewed and tested again at regular intervals for 2 years. The VMB of a subset of 174 women was characterized by phylogenetic microarray. Outcomes of STI and VMB were compared between women with hormonal exposures (reporting oral contraceptive or injectable use, or testing positive for pregnancy) and controls (not reporting hormonal contraception and not pregnant). RESULTS: Oral contraceptive use was associated with increased human papillomavirus prevalence (adjusted odds ratio [aOR], 3.10; 1.21-7.94) and Chlamydia trachomatis incidence (aOR, 6.13; 1.58-23.80), injectable use with increased herpes simplex virus-2 prevalence (aOR, 2.13; 1.26-3.59) and pregnancy with lower HIV prevalence (aOR, 0.45; 0.22-0.92) but higher candidiasis incidence (aOR, 2.14; 1.12-4.09). Hormonal status was not associated with Nugent score category or phylogenetic VMB clustering, but oral contraceptive users had lower semiquantitative vaginal abundance of Prevotella, Sneathia/Leptotrichia amnionii, and Mycoplasma species. CONCLUSIONS: Oral contraceptive and injectable use were associated with several STIs but not with VMB composition. The increased herpes simplex virus-2 prevalence among injectable users might explain the potentially higher HIV risk in these women, but more research is needed to confirm these results and elucidate biological mechanisms.

Lactobacillus-dominated cervicovaginal microbiota associated with reduced HIV/STI prevalence and genital HIV viral load in African women.

Cervicovaginal microbiota not dominated by lactobacilli may facilitate transmission of HIV and other sexually transmitted infections (STIs), as well as miscarriages, preterm births and sepsis in pregnant women. However, little is known about the exact nature of the microbiological changes that cause these adverse outcomes. In this study, cervical samples of 174 Rwandan female sex workers were analyzed cross-sectionally using a phylogenetic microarray. Furthermore, HIV-1 RNA concentrations were measured in cervicovaginal lavages of 58 HIV-positive women among them. We identified six microbiome clusters, representing a gradient from low semi-quantitative abundance and diversity dominated by Lactobacillus crispatus (cluster R-I, with R denoting 'Rwanda') and L. iners (R-II) to intermediate (R-V) and high abundance and diversity (R-III, R-IV and R-VI) dominated by a mixture of anaerobes, including Gardnerella, Atopobium and Prevotella species. Women in cluster R-I were less likely to have HIV (P=0.03), herpes simplex virus type 2 (HSV-2; P<0.01), and high-risk human papillomavirus (HPV; P<0.01) and had no bacterial STIs (P=0.15). Statistically significant trends in prevalence of viral STIs were found from low prevalence in cluster R-I, to higher prevalence in clusters R-II and R-V, and highest prevalence in clusters R-III/R-IV/R-VI. Furthermore, only 10% of HIV-positive women in clusters R-I/R-II, compared with 40% in cluster R-V, and 42% in clusters R-III/R-IV/R-VI had detectable cervicovaginal HIV-1 RNA (Ptrend=0.03). We conclude that L. crispatus-dominated, and to a lesser extent L. iners-dominated, cervicovaginal microbiota are associated with a lower prevalence of HIV/STIs and a lower likelihood of genital HIV-1 RNA shedding.