Plasma concentration of injectable contraceptive correlates with reduced cervicovaginal growth factor expression in South African women

Abstract

Long-acting injectable contraceptives have been associated with mucosal immune changes and increased HIV acquisition, but studies have often been hampered by the inaccuracy of self-reported data, unknown timing of injection, and interactions with mucosal transmission co-factors. We used mass spectrometry to quantify the plasma concentrations of injectable contraceptives in women from the CAPRISA004 study (n = 664), with parallel quantification of 48 cytokines and >500 host proteins in cervicovaginal lavage. Higher DMPA levels were associated with reduced CVL concentrations of GCSF, MCSF, IL-16, CTACK, LIF, IL-1α, and SCGF-β in adjusted linear mixed models. Dose-dependent relationships between DMPA concentration and genital cytokines were frequently observed. Unsupervised clustering of host proteins by DMPA concentration suggest that women with low DMPA had increases in proteins associated with mucosal fluid function, growth factors, and keratinization. Although DMPA was not broadly pro-inflammatory, DMPA was associated with increased IP-10 in HSV-2 seropositive and older women. DMPA-cytokine associations frequently differed by vaginal microbiome; in non-Lactobacillus-dominant women, DMPA was associated with elevated IL-8, MCP-1, and IP-10 concentrations. These data confirm a direct, concentration-dependant effect of DMPA on functionally important immune factors within the vaginal compartment. The biological effects of DMPA may vary depending on age, HSV-2 status, and vaginal microbiome composition.

Fig. 1. Correlation between plasma DMPA depletion over time in months.

Different colors display different PIDs.

Fig. 2. The effect of MPA levels on cervicovaginal cytokines milieu stratified by pro-inflammatory cytokines (red), chemokines (green), growth factors (purple), adaptive factors (blue), and anti-inflammatory cytokines (gray).

a An unadjusted model conducted using 426 samples of n = 390 women with detectable MPA, compared with 98 samples of n = 91 women without detectable contraceptive. b Model adjusting for HSV-2, age, study arm, study site, number of sex acts per month, condom use, and microbial grouping using 356 samples from n = 344 women with MG data and have detectable MPA compared with 90 samples of n = 86 women without detectable contraceptive. Stars denotes the degree of significance: *p < 0.05, **p < 0.01, ***p < 0.001.

Fig. 3

Interaction analsysis showing the impact of detectable MPA vs. non-detectable MPA on cervical cytokines stratified by (a) baseline HSV-2, (b) age, and (c) microbial grouping (MG). Pro-inflammatory cytokines (red), chemokines (green), growth factors (purple), adaptive factors (blue), and anti-inflammatory cytokines (gray). Stars denotes the degree of significance: *p < 0.05, **p < 0.01, ***p < 0.001. The P-value of the interaction analysis is represented using boxes: p < 0.05 (red box), p > 0.05, and ≤0.1 (green box), and p > 0.1 and ≤ 0.2 (blue box). For baseline HSV-2 and age, interaction and stratification analysis were conducted using 426 samples of n = 390 women with detectable MPA, compared with 98 samples of n = 91 women without detectable contraceptive, whereas for MG 356 samples of n = 344 women with MG data and have detectable MPA compared with 90 samples of n = 86 women without detectable contraceptive.

Fig. 4

Protein clusters with MPA/growth factor levels showing (a) the number of proteins which were associated with MPA levels. b Hierarchical cluster analysis of proteins associated with MPA levels formed four sub-branches based on protein expression patterns. c Quartile figures were used to show the frequency of women associated with MPA, MCSF, and GCSF levels.