Intestinal Barrier Dysfunction and Microbial Translocation in Human Immunodeficiency Virus-Infected Pregnant Women Are Associated With Preterm Birth

Maternal inflammatory and microbial drivers of low birthweight in low- and middle-income countries

BACKGROUND

Low birthweight (LBW) is when an infant is born too soon or too small, and it affects one in seven infants in low- and middle-income countries. LBW has a significant impact on short-term morbidity and mortality, and it impairs long-term health and human capital. Antenatal microbial and inflammatory exposure may contribute to LBW.

METHODS

Ovid-Medline, Embase and Cochrane databases were searched for English-language articles evaluating inflammatory, microbial or infective causes of LBW, small-for-gestational age, intra-uterine growth restriction or prematurity. Inclusion criteria were human studies including published data; conference abstracts and grey literature were excluded. A narrative synthesis of the literature was conducted.

RESULTS

Local infections may drive the underlying causes of LBW: for example, vaginitis and placental infection are associated with a greater risk of prematurity. Distal infection and inflammatory pathways are also associated with LBW, with an association between periodontitis and preterm delivery and environmental enteric dysfunction and reduced intra-uterine growth. Systemic maternal infections such as malaria and HIV are associated with LBW, even when infants are exposed to HIV but not infected. This latter association may be driven by chronic inflammation, co-infections and socio-economic confounders. Antimicrobial prophylaxis against other bacteria in pregnancy has shown minimal impact in most trials, though positive effects on birthweight have been found in some settings with a high infectious disease burden.

CONCLUSION

Maternal inflammatory and infective processes underlie LBW, and provide treatable pathways for interventions. However, an improved understanding of the mechanisms and pathways underlying LBW is needed, given the impact of LBW on life-course.

Systemic inflammation in pregnant women with HIV: relationship with HIV treatment regimen and preterm delivery

OBJECTIVE

HIV treatment regimen during pregnancy was associated with preterm delivery (PTD) in the PROMISE 1077 BF trial. Systemic inflammation among pregnant women with HIV could help explain differences in PTD by treatment regimen. We assessed associations between inflammation, treatment regimen, and PTD.

DESIGN/METHODS

A nested 1 : 1 case-control study ( N  = 362) was conducted within a multicountry randomized trial comparing three HIV regimens in pregnant women: zidovudine alone, or combination antiretroviral therapy (ART) with lopinavir/ritonavir and either zidovudine or tenofovir. Cases were women with PTD (<37 weeks of gestational age). The following inflammatory biomarkers were measured in plasma samples using immunoassays: soluble CD14 (sCD14) and sCD163, intestinal fatty acid-binding protein, interleukin (IL)-6, interferon γ, and tumor necrosis factor α. We fit regression models to assess associations between second trimester biomarkers (measured before ART initiation at 13-23 weeks of gestational age and 4 weeks later), treatment regimen, and PTD. We also assessed whether inflammation was a mediator in the relationship between ART regimen and PTD.

RESULTS

Persistently high interleukin-6 was associated with increased PTD. Compared with zidovudine alone, the difference in biomarker concentration between week 0 and week 4 was significantly higher ( P  < 0.05) for both protease inhibitor-based regimens. However, the estimated proportion of the ART effect on increased PTD mediated by persistently high biomarker levels was 5% or less for all biomarkers.

CONCLUSION

Persistently high IL-6 during pregnancy was associated with PTD. Although protease inhibitor-based ART was associated with increases in inflammation, factors other than inflammation likely explain the increased PTD in ART-based regimens compared with zidovudine alone.

Intestinal barrier disruption with Plasmodium falciparum infection in pregnancy and risk of preterm birth: a cohort study

BACKGROUND

Malaria in early pregnancy is a risk factor for preterm birth and is associated with sustained inflammation and dysregulated angiogenesis across gestation. This study investigated whether malaria is associated with increased gut leak and whether this contributes to systemic inflammation, altered angiogenesis, and preterm birth.

METHODS

We quantified plasma concentrations of gut leak markers, soluble CD14 (sCD14) and lipopolysaccharide binding protein (LBP) from 1339 HIV-negative pregnant Malawians at <24 weeks gestational age. We assessed the relationship of sCD14 and LBP concentrations with markers of inflammation, angiogenesis, and L-arginine bioavailability and compared them between participants with and without malaria, and with and without preterm birth.

FINDINGS

Plasma concentrations of sCD14 and LBP were significantly higher in participants with malaria and were associated with parasite burden (p <0.0001, both analyses and analytes). The odds ratio for preterm birth associated with one log sCD14 was 2.67 (1.33 to 5.35, p = 0.006) and 1.63 (1.07-2.47, p = 0.023) for LBP. Both gut leak analytes were positively associated with increases in proinflammatory cytokines CRP, sTNFR2, IL18-BP, CHI3L1 and Angptl3 (p <0.05, all analytes) and sCD14 was significantly associated with angiogenic proteins Angpt-2, sENG and the sFLT:PlGF ratio (p <0.05, all analytes). sCD14 was negatively associated with L-arginine bioavailability (p <0.001).

INTERPRETATION

Malaria in early pregnancy is associated with intestinal barrier dysfunction, which is linked to an increased risk of preterm birth.

FUNDING

Open Philanthropy, Canadian Institutes of Health Research, Canada Research Chair program, European and Developing Countries Clinical Trials Partnership, Bill & Melinda Gates Foundation.

Markers of intestinal immune activation and inflammation are not associated with preterm birth among women with low level HIV viremia

BACKGROUND

Maternal markers of intestinal immune activation may be used to predict preterm birth (PTB) in pregnant women living with HIV.

METHODS

This study used de-identified samples from the International Maternal Pediatric Adolescent AIDS Clinical Trials Group (IMPAACT) Protocol P1025 study. Singleton pregnancies with ≥3 ml plasma available and HIV viral load ≤400 copies/ml within 4 weeks of specimen collection were included. Frequency matching of PTB cases and term birth controls was performed on basis of maternal race, number of available plasma specimens, and timing of plasma sample collection in a 1:1 ratio. Plasma progesterone, 25-hydroxy vitamin D, soluble CD14, intestinal fatty acid binding protein (I-FABP), Lipopolysaccharide (LPS)-binding protein, and inflammatory cytokines (IL-1B, IFN-gamma, IL-6, TNF-alpha) were measured. Generalized mixed linear regression modeling was used to examine the association between PTB and biomarkers, adjusting for covariates and confounders. Data analyses were performed using SAS 9.4 (Cary, NC).

RESULTS

We included 104 PTB compared to 104 controls. Third trimester log2 IL-1B was lower among PTB versus term birth controls by univariate analysis (-1.50 ± 2.26 vs. -.24 ± 2.69, p = .01) though this association was no longer significant by regression modeling. In an uncontrolled, exploratory sub-analysis, subjects with prior PTB had increased odds of PTB with higher I-FABP [aOR 2.72, 95% CI 1.18-6.24] and lower IFN-gamma [aOR .23, 95% CI .12-.41] after adjustment for covariates and confounders.

CONCLUSIONS

Intestinal immune activation measured by soluble CD14 or intestinal fatty acid binding protein was not associated with preterm birth among pregnant women with low-level HIV viremia.

Unique Profile of Inflammation and Immune Activation in Pregnant People With HIV in the United States

BACKGROUND

Little is known about inflammation/immune activation during pregnancy in people with HIV (PWH) and growth in their children who are HIV-exposed and uninfected (CHEU).

METHODS

Using data from the Pediatric HIV/AIDS Cohort Study and an HIV-seronegative comparison group, we assessed associations of (1) HIV status, mode of HIV acquisition (perinatally vs nonperinatally acquired), and type of antiretroviral therapy (ART) with inflammation/immune activation in pregnancy; and (2) inflammation/immune activation in pregnancy with growth of CHEU at 12 months. Interleukin 6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), soluble(s) TNF-α receptor 1 and 2 (sTNFR1, sTNFR2), sCD14, and sCD163 were measured between 13 and 27 weeks' gestation. Linear regression models were fit to estimate differences between groups for each log-transformed biomarker, adjusted for confounders.

RESULTS

Pregnant PWH (188 total, 39 perinatally acquired, 149 nonperinatally acquired) and 76 HIV-seronegative persons were included. PWH had higher IL-6, sTNFR1, sCD14, and sCD163 and lower sTNFR2 compared to HIV-seronegative persons in adjusted models. Among PWH, sCD163 was higher in those with perinatally versus nonperinatally acquired HIV and on PI-based versus INSTI-based ART. Higher maternal concentrations of IL-6, sTNFR2, and hs-CRP were associated with poorer growth at 12 months.

CONCLUSIONS

Maternal HIV status is associated with a distinct profile of inflammation/immune activation during pregnancy, which may influence child growth.

Pregnancy Related Venous Thromboembolism-Associated with HIV Infection and Antiretroviral Therapy

Human immunodeficiency virus (HIV) infection in pregnancy is associated with substantial morbidity and mortality. Improved access to effective antiretroviral therapy (ART) has shifted the spectrum of pregnancy-related complications among HIV-infected pregnant women. In addition to placental vascular complications and preterm delivery, increased rates of venous thromboembolism (VTE) have been described. HIV infection is characterized by immune activation, inflammation, and endothelial dysfunction, which contribute to the activation of coagulation and its prothrombotic consequences. Indeed, activated coagulation factors have been reported to be increased and natural anticoagulants reduced in HIV. Several mechanisms for this persistent prothrombotic balance on ART have been identified. These may include: co-infections, immune recovery, and loss of the gastrointestinal mucosal integrity with microbial translocation. In addition to the direct effects of HIV and ART, traditional venous and obstetric risk factors also contribute to the risk of VTE. A research priority has been to understand the mechanisms of VTE in HIV-infected pregnant women receiving suppressive ART and to translate this into HIV-specific thromboprophylaxis recommendations. Management requires a multidisciplinary approach and further studies are indicated to guide the prevention and management of pregnancy-associated VTE in this population. The current review describes the epidemiology, mechanisms, and management of VTE in HIV-infected women in pregnancy and the postpartum period.

Evaluation of markers of fibrinolysis and coagulation in pregnant women with human immunodeficiency virus

INTRODUCTION

Human immunodeficiency virus (HIV) in pregnant women is characterized by immune activation and inflammation despite suppressive antiretroviral therapy (ART). The extent to which ongoing inflammation contributes to activation of coagulation and fibrinolysis is unknown.

MATERIALS AND METHODS

This cross-sectional study included pregnant women in the following three groups: HIV negative (n = 109), HIV infected virologically suppressed (n = 109) and HIV infected with HIV viral load (VL) of >50 copies/mL (n = 80). Fibrinolytic activity was evaluated by measuring d-dimer and plasminogen activator inhibitor-1 (PAI-1) as well as thrombin-antithrombin (TAT) complex concentrations, as an index of coagulation, in the first, second and third trimesters.

RESULTS

In this population, with a mean age of 33 ± 6 years, pregnancy outcomes were recorded for 277 (93.0 %) participants with live births. HIV infected participants with virological suppression and VL of >50 copies/mL showed significantly increasing levels of d-dimer and PAI-1 in the first, second and third trimesters, as compared to HIV negative participants. No significant differences were observed between HIV infected participants with virological suppression and HIV infected participants with VL > 50 copies/mL for levels of first and third trimester d-dimer and PAI-1 in each trimester. In addition, TAT complex levels in the first trimester were significantly increased in HIV infected virologically suppressed participants as compared to HIV negative participants.

CONCLUSION

HIV infected virologically suppressed pregnant women show evidence of persistently impaired markers of fibrinolysis. Future research should explore the risk of adverse pregnancy complications among HIV infected pregnant women in the modern era of ART.

Study of Treatment and Reproductive Outcomes Among Reproductive-Age Women With HIV Infection in the Southern United States: Protocol for a Longitudinal Cohort Study

BACKGROUND

Nearly a quarter of the 1.1 million individuals with HIV in the United States are women. Racial and ethnic minority women in the Southern United States are disproportionately impacted. Reproductive-age women with HIV are prone to poor HIV outcomes but remain underrepresented in HIV research. We will answer contemporary questions related to the health outcomes in this population by enrolling a prospective cohort of reproductive-age women with and without HIV in the Southern United States.

OBJECTIVE

The Study of Treatment and Reproductive Outcomes (STAR) will enroll and retain 2000 reproductive-age women with and without HIV. The STAR will leverage the infrastructure of the US-based Multicenter AIDS Cohort Study (MACS)/Women's Interagency HIV Study (WIHS) Combined Cohort Study, comprising the WIHS (a cohort of women with and at risk for HIV, which began in 1993), and the MACS (a cohort of gay and bisexual men with and at risk for HIV, which began in 1984). Although the advancing age of the participants enrolled in the MACS/WIHS Combined Cohort Study provides an opportunity to address the questions related to HIV and aging, the research questions pertinent to the reproductive years must also be addressed. The STAR will conduct high-priority scientific research in key areas with the overall aim of addressing the unique needs of reproductive-age women with HIV.

METHODS

The STAR is a prospective, observational cohort study that will be conducted at 6 sites in the United States-Atlanta, Georgia; Birmingham, Alabama; Jackson, Mississippi; Chapel Hill, North Carolina; Miami, Florida; and Washington, District of Columbia. Visits will occur semiannually for 2 years, with additional visits for up to 5 years. At each visit, the participating women will complete a structured interview for collecting key demographic, psychosocial, and clinical variables, and undergo biospecimen collection for laboratory testing and repositing (blood, urine, hair, vaginal, anal, and oral specimens). Pregnant women and infants will undergo additional study assessments. The initial scientific focus of the STAR is to understand the roles of key social determinants of health, depression, reproductive health, and oral health on HIV and pregnancy outcomes across the reproductive life span.

RESULTS

Enrollment in the STAR commenced in February 2021 and is ongoing.

CONCLUSIONS

Through in-depth, longitudinal data and biospecimen collection, the newly initiated STAR cohort will create a platform to answer scientific questions regarding reproductive-age women with and without HIV. STAR will be uniquely positioned to enable investigators to conduct high-impact research relevant to this population. Building on the legacy of the MACS and WIHS cohorts, the STAR is designed to foster multidisciplinary collaborations to galvanize scientific discoveries to improve the health of reproductive-age women with HIV and ameliorate the effects of the HIV epidemic in this population in the United States.

Association of Maternal Inflammation During Pregnancy With Birth Outcomes and Infant Growth Among Women With or Without HIV in India

IMPORTANCE

The association of elevated levels of specific inflammatory markers during pregnancy with adverse birth outcomes and infant growth could indicate pathways for potential interventions.

OBJECTIVE

To evaluate whether higher levels of certain inflammatory markers during pregnancy are associated with preterm birth (PTB), low birth weight (LBW), and infant growth deficits.

DESIGN, SETTING, AND PARTICIPANTS

In this cohort study of pregnant women with or without HIV, 218 mother-infant pairs were followed up from pregnancy through 12 months post partum from June 27, 2016, to December 9, 2019. Pregnant women aged 18 to 40 years and between 13 and 34 weeks of gestation who were receiving antenatal care were enrolled in a cohort stratified by HIV status; sampling was based on convenience sampling from women receiving antenatal care at Byramjee Jeejeebhoy Government Medical College.

EXPOSURES

Levels of multiple circulating inflammation markers during the third trimester of pregnancy.

MAIN OUTCOMES AND MEASURES

The primary study outcome was PTB (<37 weeks' gestation). Secondary outcomes were LBW (<2500 g) and repeated measures (delivery; 6 weeks post partum; and 3, 6, and 12 months post partum using multivariable generalized linear models) of infant growth outcomes (length-for-age, weight-for-age, and weight-for-length z scores).

RESULTS

The median age of the 218 women at enrollment was 23 years (IQR, 21-27 years). In multivariable models, higher pregnancy levels of interleukin 17A were associated with increased odds of both PTB (adjusted odds ratio [aOR], 2.62; 95% CI, 1.11-6.17) and LBW (aOR, 1.81; 95% CI, 1.04-3.15). Higher levels of interleukin 1β were associated with increased PTB (aOR, 1.47; 95% CI, 1.15-1.89) and infant growth deficits (lower length-for-age z score: adjusted β = -0.10; 95% CI, -0.18 to -0.01; lower weight-for-age z score: adjusted β = -0.07; 95% CI, -0.14 to 0.001).

CONCLUSIONS AND RELEVANCE

This study suggests that increased levels of certain systemic inflammatory markers, including interleukin 1β and interleukin 17A, during pregnancy were associated with adverse birth outcomes and infant growth deficits. Future studies should evaluate whether potential interventions to modulate specific inflammatory pathways during pregnancy could improve birth outcomes and infant growth.

von Willebrand factor propeptide-to-antigen ratio in HIV-infected pregnancy: Evidence of endothelial activation

BACKGROUND

Endothelial activation has been proposed as a potential mechanism for the increased risk of venous thromboembolism (VTE) in human immunodeficiency virus (HIV)-infected pregnancy.

OBJECTIVES

To assess the state of endothelial activation in HIV-infected pregnancy by measuring the von Willebrand factor (VWF) propeptide-to-antigen ratio, as an index of acute endothelial activation.

METHODS

VWF antigen and VWF propeptide were measured in HIV-negative participants (n = 85), HIV-infected virologically suppressed participants, (n = 89) and HIV-infected participants with HIV viral load (VL) of >50 copies/ml (n = 63) in each trimester. Results were correlated with multimer patterns and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS-13) antigen, activity, and antibody levels.

RESULTS

VWF propeptide-to-antigen ratio was increased, in the first, second, and third trimester, in the HIV-infected virologically suppressed group (1.7 ± 0.7, 1.7 ± 0.4, 1.6 ± 0.5) and the HIV-infected group with VL > 50 copies/ml (1.9 ± 0.9, 1.7 ± 0.9, 1.6 ± 1.1) compared to the HIV-negative group (1.4 ± 0.6, 1.3 ± 0.4, 1.2 ± 0.3, P < .05). Increased high molecular weight multimers were observed in the HIV-infected groups, despite only a mild reduction in ADAMTS-13 activity compared to the HIV-negative group (P < .001). No correlation was observed between VWF antigen or VWF propeptide and ADAMTS-13 activity.

CONCLUSION

HIV-infected virologically suppressed pregnant participants showed persistent endothelial activation. Future research should focus on whether endothelial activation contributes to the excess risk of pregnancy-related VTE.

Impact of HIV status on systemic inflammation during pregnancy

OBJECTIVE

There are limited studies on the association of HIV infection with systemic inflammation during pregnancy.

DESIGN

A cohort study (N = 220) of pregnant women with HIV (N = 70) (all on antiretroviral therapy) and without HIV (N = 150) were enrolled from an antenatal clinic in Pune, India.

METHODS

The following systemic inflammatory markers were measured in plasma samples using immunoassays: soluble CD163 (sCD163), soluble CD14 (sCD14), intestinal fatty acid-binding protein (I-FABP), C-reactive protein (CRP), alpha 1-acid glycoprotein (AGP), interferon-β (IFNβ), interferon-γ (IFNγ), interleukin (IL)-1β, IL-6, IL-13, IL-17A, and tumor necrosis factor α (TNFα). Generalized estimating equation (GEE) and linear regression models were used to assess the association of HIV status with each inflammatory marker during pregnancy and by trimester, respectively.

RESULTS

Pregnant women with HIV had higher levels of markers for gut barrier dysfunction (I-FABP), monocyte activation (sCD14) and markers of systemic inflammation (IL-6 and TNFα), but surprisingly lower levels of AGP, an acute phase protein, compared with pregnant women without HIV, with some trimester-specific differences.

CONCLUSION

Our data show that women with HIV had higher levels of markers of gut barrier dysfunction, monocyte activation and systemic inflammation. These markers, some of which are associated with preterm birth, might help explain the increase in adverse birth outcomes in women with HIV and could suggest targets for potential interventions.

Maternal fecal microbiome predicts gestational age, birth weight and neonatal growth in rural Zimbabwe

BACKGROUND

Preterm birth and low birth weight (LBW) affect one in ten and one in seven livebirths, respectively, primarily in low-income and middle-income countries (LMIC) and are major predictors of poor child health outcomes. However, both have been recalcitrant to public health intervention. The maternal intestinal microbiome may undergo substantial changes during pregnancy and may influence fetal and neonatal health in LMIC populations.

METHODS

Within a subgroup of 207 mothers and infants enrolled in the SHINE trial in rural Zimbabwe, we performed shotgun metagenomics on 351 fecal specimens provided during pregnancy and at 1-month post-partum to investigate the relationship between the pregnancy gut microbiome and infant gestational age, birth weight, 1-month length-, and weight-for-age z-scores using extreme gradient boosting machines.

FINDINGS

Pregnancy gut microbiome taxa and metabolic functions predicted birth weight and WAZ at 1 month more accurately than gestational age and LAZ. Blastoscystis sp, Brachyspira sp and Treponeme carriage were high compared to Western populations. Resistant starch-degraders were important predictors of birth outcomes. Microbiome capacity for environmental sensing, vitamin B metabolism, and signalling predicted increased infant birth weight and neonatal growth; while functions involved in biofilm formation in response to nutrient starvation predicted reduced birth weight and growth.

INTERPRETATION

The pregnancy gut microbiome in rural Zimbabwe is characterized by resistant starch-degraders and may be an important metabolic target to improve birth weight.

FUNDING

Bill and Melinda Gates Foundation, UK Department for International Development, Wellcome Trust, Swiss Agency for Development and Cooperation, US National Institutes of Health, and UNICEF.

Pregnancy-related venous thromboembolism and HIV infection

OBJECTIVE

To assess risk factors for venous thromboembolism (VTE) in African women in order to guide thromboprophylaxis.

METHODS

A case-control study was performed at a specialist obstetric unit in South Africa from July 1, 2017 to June 30, 2020. We identified 128 cases with VTE and 640 controls, matched for gestation.

RESULTS

Prepartum risk factors associated with VTE included; medical comorbidities (odds ratios [OR] 5.32, 95% confidence intervals [CI] 1.82-15.56), human immunodeficiency virus (HIV) (OR 2.84, 95% CI 1.50-5.41), and hospital admission or immobility (OR 5.33, 95% CI 1.17-24.22). Postpartum, the following were identified as significant risk factors; medical comorbidities (OR 23.72, 95% CI 8.75-64.27), hospital admission or immobility (OR 13.18, 95% CI 5.04-34.49), systemic infection (OR 4.48, 95% CI 1.28-15.68), HIV (OR 3.20, 95% CI 1.49-6.87), pre-eclampsia and fetal growth restriction (OR 2.74, 95% CI 1.18-6.36), and postpartum hemorrhage (OR 4.38, 95% CI 1.75-10.97). Antiretroviral therapy, opportunistic infections, and viral load >50 copies/ml, however, were not associated with VTE risk among HIV-infected participants.

CONCLUSION

HIV was a significant risk factor for pregnancy-related thrombosis. This was independent of traditional HIV risk factors. As such, future studies are recommended to explore the mechanisms of thrombosis associated with HIV infection.

Association of Vegetable and Animal Flesh Intake with Inflammation in Pregnant Women from India

In pregnant women, studies are lacking on the relationship of vegetable and animal flesh (poultry, red meat and seafood) intake with inflammation, especially in low- and middle-income countries. We conducted a cohort study of pregnant women receiving antenatal care at BJ Medical College in Pune, India. The dietary intake of pregnant women was queried in the third trimester using a validated food frequency questionnaire. Twelve inflammatory markers were measured in plasma samples using immunoassays. Only 12% of the study population were vegetarians, although animal flesh intake levels were lower compared to Western populations. In multivariable models, higher intakes of total vegetables were associated with lower levels of the T-helper (Th) 17 cytokine interleukin (IL)-17a (p = 0.03) and the monocyte/macrophage activation marker soluble CD163 (sCD163) (p = 0.02). Additionally, higher intakes of poultry were negatively associated with intestinal fatty-acid binding protein (I-FABP) levels (p = 0.01), a marker of intestinal barrier dysfunction and Th2 cytokine IL-13 (p = 0.03), and higher seafood was associated with lower IL-13 (p = 0.005). Our data from pregnant women in India suggest that a higher quality diet emphasizing vegetables and with some animal flesh is associated with lower inflammation. Future studies should confirm these findings and test if modulating vegetables and animal flesh intake could impact specific aspects of immunity and perinatal health.