Genital Injury Signatures and Microbiome Alterations Associated With Depot Medroxyprogesterone Acetate Usage and Intravaginal Drying Practices

Abstract

Background: Increasing evidence suggests depot medroxyprogesterone acetate (DMPA) and intravaginal practices may be associated with human immunodeficiency virus (HIV-1) infection risk; however, the mechanisms are not fully understood. This study evaluated the effect of DMPA and intravaginal practices on the genital proteome and microbiome to gain mechanistic insights.

Methods: Cervicovaginal secretions from 86 Kenyan women, including self-reported DMPA users (n = 23), nonhormonal contraceptive users (n = 63), and women who practice vaginal drying (n = 46), were analyzed using tandem-mass spectrometry.

Results: We identified 473 human and 486 bacterial proteins from 18 different genera. Depot medroxyprogesterone acetate use associated with increased hemoglobin and immune activation (HBD, HBB, IL36G), and decreased epithelial repair proteins (TFF3, F11R). Vaginal drying associated with increased hemoglobin and decreased phagocytosis factors (AZU1, MYH9, PLAUR). Injury signatures were exacerbated in DMPA users who also practiced vaginal drying. More diverse (H index: 0.71 vs 0.45; P = .009) bacterial communities containing Gardnerella vaginalis associated with vaginal drying, whereas DMPA showed no significant association with community composition or diversity.

Conclusions: These findings provide new insights into the impact of DMPA and vaginal drying on mucosal barriers. Future investigations are needed to confirm their relationship with HIV risk in women.

Keywords: DMPA; Depot medroxyprogesterone acetate; HIV; Mucosa; genital injury; metaproteome; microbiome; progestin; proteomics; vaginal drying.

Figure 1.

Increased injury signals in the female genital tract mucosa are associated with the use of depot medroxyprogesterone acetate (DMPA) and vaginal drying. A, Hierarchical clustering of differentially abundant proteins among DMPA users and nonhormonal contraceptive user controls (Kendall’s tau distance metric, complete linkage). Inflammatory response proteins found to be overabundant in DMPA users are highlighted. B, Hemoglobin subunit delta levels were examined as a blood/injury biomarker. Individuals with levels 1.5 fold higher than the mean were considered to have an injury signature. Vaginal drying independently was significantly associated with an increased risk of injury (P = .01), as was DMPA (P = .004), and the combination of DMPA use and vaginal drying together was associated with an even greater injury signal (P = .0001). Statistical comparisons were performed using unpaired Student’s t tests. The comparisons shown are between each separate variable (vaginal wash, vaginal dry, DMPA, and DMPA with vaginal drying) and controls (women who do not vaginal wash or dry or use DMPA) where each variable was adjusted for in its own model.

Figure 2.

Vaginal bacterial profiles by mass spectrometry reveal 2 distinct microbial community structures. A, Bacterial abundances were calculated by summing normalized total spectral counts for all proteins associated with each genus. Hierarchical clustering of the samples was performed using unsupervised, average Euclidean linkage of the proportional bacterial abundance of each sample, resulting in 2 major clusters: one dominated by Lactobacillus (group I), and the other dominated by non-Lactobacillus bacteria (group II). Subgroups are as follows: A = Lactobacillus predominance; B = Lactobacillus/Clostridium heterogeneous; C = Gardnerella vaginalis predominance, D = Pseudomonas and Streptomyces predominance. B, Shannon’s diversity indices were compared between women who vaginally washed, vaginally dried, or used depot medroxyprogesterone acetate (DMPA) and their respective controls, showing increased ecological diversity associated with vaginal drying practices (Mann-Whitney U test, ** = P < .01).

Figure 3.

Model of molecular effects of depot medroxyprogesterone acetate (DMPA) use on the vagina mucosa. The use of DMPA is associated with a molecular signature, which suggests that the genital epithelium is weak and likely more prone to injury when faced with any kind of mechanical stress. Breach signals are evident, leading to an increase in the release of inflammatory molecules, which serve to attract immune cells to the breach site. Proteins involved in this inflammatory signalling cascade are increased in women using DMPA, whereas mucosal protection and repair proteins are reduced. This lack of mucosal protection and reparation may further exacerbate risk of human immunodeficiency virus (HIV) infection in DMPA users as the portal of entry that is generated is likely slow to heal. Further to this, DMPA users who practice vaginal drying appear to exacerbate this phenomenon, which likely contributes to an even great risk of HIV infection due to this compounding effect.