Background: Women living with HIV-1 (WLHIV) are at higher risk of having an adverse birth outcome, but the underlying mechanism(s) are unknown. We hypothesized that HIV-associated endothelial activation could adversely impact placental function and lead to impaired fetal growth or stillbirth.
Methods: We used stored samples from WLHIV and HIV-negative women who had enrolled during pregnancy in the observational Botswana Tshipidi cohort. Written informed consent was obtained from the participants. We measured plasma levels of markers of endothelial activation (soluble vascular adhesion molecule 1 [VCAM-1], intercellular adhesion molecule 1 [ICAM-1] and E-selectin) from samples taken during pregnancy. We compared log10 biomarker levels by maternal HIV status and by the timing of ART initiation (ART prior to conception vs. during pregnancy; ART prior to sample collection vs. no ART prior to sampling) using t-tests and the Kruskal-Wallis rank test. We evaluated the association between these biomarkers and adverse birth outcomes (composite of stillbirth or small for gestational age [SGA]) using univariate and multivariate log-binomial regression controlling for maternal age (continuous) and timing of ART start. We also used generalized linear models (GLM) to evaluate the association between continuous birthweight (in grams) and gestational age (in weeks) and markers of endothelial dysfunction, adjusting for maternal age (continuous) and timing of ART relative to sample collection.
Results: Specimens collected before delivery were available for 414 women (372 WLHIV and 42 HIV-negative women), with a median age of 28 years and median gestational age at sample collection of 30 weeks (range 26, 35 weeks). WLHIV had significantly higher median VCAM1 (p = 0.002) than HIV-negative women, but HIV-negative women had higher median ICAM1 (p = 0.01); e-Selectin levels did not differ by maternal HIV status. Women starting ART during pregnancy had higher log10 VCAM1 levels than those on ART before conception, regardless of whether the sample was collected before (p = 0.02) or after (p = 0.03) ART initiation. However, ICAM1 and e-Selectin did not differ significantly by ART status or ART timing. Ninety-eight women (91 WLHIV and 7 HIV-negative), or 9 (2%) and 89 (22%) included in this study, had a stillborn or SGA baby respectively. Univariate and adjusted analyses did not show significant associations between levels of any of the biomarkers with these adverse birth outcomes. However, lower birthweight (p = 0.03) and lower gestational age at delivery were associated e-Selectin and ICAM (p = 0.008), respectively.
Conclusion: Maternal HIV infection and lack of ART (or recent ART initiation) were associated with one marker of greater endothelial activation (VCAM-1), but not with other markers (ICAM-1 nor E-selectin) in pregnancy. e-Selectin was associated with lower birthweight and every unit increase in log ICAM-1 at delivery was associated with lower gestation age at delivery.