Inflammatory biomarkers and spontaneous preterm birth among obese women

Finding the priority and cluster of inflammatory biomarkers for infectious preterm birth: a systematic review

Infectious preterm birth (PTB) is one of the most important causes of perinatal death. It is difficult to find reliable biomarkers accurate to gestational weeks for infectious PTB prediction clinically. Infectious PTB is found usually accompanied with immune imbalance. Thus, the systematic study to find the priority of inflammatory biomarkers and innovative inflammatory clusters for infectious PTB prediction is urgently needed.This systematic study that focused on the inflammatory clusters and infectious PTB in the PubMed database was analyzed by using the criteria of the Population, Intervention, Comparison, Outcome, and Study design (PICOS) framework according to the recommendations of preferred reporting items for systematic reviews and meta-analysis (PRISMA).The network meta-analyzed results showed that the prioritization of the inflammatory factors for infectious PTB prediction is soluble tumor necrosis factor receptor 2 (sTNFR2) > tumor necrosis factor α (TNFα) > interleukin-10 (IL-10) > interleukin-6 (IL-6) > C-reactive protein (CRP) > interleukin-1β (IL-1β). Furthermore, the results also indicated that global consideration of multiple inflammatory factors, such as CRP/IL-1β/IL-6 biomarker cluster in gestational 27-34 weeks, and the tumor necrosis factor/nerve growth factor (TNF/NGF) family during gestational 25-33 weeks, were potential biomarker clusters that specific for infectious PTB prediction.This study systematically pointed out prioritization of the inflammatory factors for infectious PTB prediction. The results also provided evidence that maternal inflammatory clusters can predict infectious PTB occurrence at accurate gestational week. The global consideration of multiple inflammatory factors at accurate gestational age is highlighted.

Sequential disruptions to inflammatory and angiogenic pathways and risk of spontaneous preterm birth in Malawian women

Preterm birth is a leading cause of death in children under five years of age. We hypothesized that sequential disruptions to inflammatory and angiogenic pathways during pregnancy increase the risk of placental insufficiency and spontaneous preterm labor and delivery. We conducted a secondary analysis of inflammatory and angiogenic analytes measured in plasma samples collected across pregnancy from 1462 Malawian women. Women with concentrations of the inflammatory markers sTNFR2, CHI3L1, and IL18BP in the highest quartile before 24 weeks gestation and women with anti-angiogenic factors sEndoglin and sFlt-1/PlGF ratio in the highest quartile at 28-33 weeks gestation had an increased relative risk of preterm birth. Mediation analysis further supported a potential causal link between early inflammation, subsequent angiogenic dysregulation detrimental to placental vascular development, and earlier gestational age at delivery. Interventions designed to reduce the burden of preterm birth may need to be implemented before 24 weeks of gestation.

Impact of maternal obesity on preterm delivery in patients with cervical cerclage

BACKGROUND

Maternal obesity has risen in the United States in recent decades.

OBJECTIVE

This study aimed to evaluate the impact of maternal obesity on the risk for spontaneous preterm delivery and the risk for overall preterm delivery among patients with cervical cerclage placement.

STUDY DESIGN

This was a retrospective study in which data from the California Office of Statewide Health Planning and Development linked birth file from 2007 to 2012 were used, yielding a total of 3654 patients with and 2,804,671 patients without cervical cerclage placement. Exclusion criteria included patients with missing information on body mass index, multiple gestation, anomalous pregnancies, and gestations <20 weeks or >42 weeks. Patients in each group were identified and were further categorized based on body mass index with the nonobese group defined as having a body mass index of <30 kg/m², the obese group defined as having a body mass index of 30 to 40 kg/m², and the morbidly obese group defined as having a body mass index >40 kg/m². The risks for overall and spontaneous preterm delivery were compared between patients without obesity and those with obesity or those with morbid obesity patients. The analysis was stratified by cerclage placement.

RESULTS

Among patients who underwent cerclage placement, the risk for spontaneous preterm delivery was not significantly different in the obese and morbidly obese group when compared with the nonobese group (24.2% vs 20.6%; adjusted odds ratio, 1.18; 95% confidence interval, 0.97-1.43; and 24.5% vs 20.6%; adjusted odds ratio, 1.12; 0.78-1.62, respectively). However, among patients without cerclage placement, the obese and morbidly obese groups had a higher risk for spontaneous preterm delivery than the nonobese group (5.1% vs 4.4%; adjusted odds ratio, 1.04; 1.02-1.05; and 5.9% vs 4.4%; adjusted odds ratio, 1.03; 1.00-1.07, respectively). The risks for overall preterm delivery at <37 weeks' gestation were higher for the obese and morbidly obese groups than for the nonobese group among patients with cerclage (33.7% vs 28.2%; adjusted odds ratio, 1.23; 1.03-1.46; and 32.1% vs 28.2%; adjusted odds ratio, 1.01; 0.72-1.43, respectively). Similarly, among patients without cerclage placement, the risks for preterm delivery at <37 weeks' gestation were higher for the obese and morbidly obese groups than for the nonobese group (7.9% vs 6.8%; adjusted odds ratio, 1.05; 1.04-1.06; and 9.3% vs 6.8%; adjusted odds ratio, 1.10; 1.08-1.13, respectively).

CONCLUSION

Among patients who received a cervical cerclage for the prevention of preterm birth, obesity was not associated with an increased risk for spontaneous preterm delivery. However, it was associated with an overall increased risk for preterm delivery.

Preterm birth buccal cell epigenetic biomarkers to facilitate preventative medicine

Preterm birth is the major cause of newborn and infant mortality affecting nearly one in every ten live births. The current study was designed to develop an epigenetic biomarker for susceptibility of preterm birth using buccal cells from the mother, father, and child (triads). An epigenome-wide association study (EWAS) was used to identify differential DNA methylation regions (DMRs) using a comparison of control term birth versus preterm birth triads. Epigenetic DMR associations with preterm birth were identified for both the mother and father that were distinct and suggest potential epigenetic contributions from both parents. The mother (165 DMRs) and female child (136 DMRs) at p < 1e-04 had the highest number of DMRs and were highly similar suggesting potential epigenetic inheritance of the epimutations. The male child had negligible DMR associations. The DMR associated genes for each group involve previously identified preterm birth associated genes. Observations identify a potential paternal germline contribution for preterm birth and identify the potential epigenetic inheritance of preterm birth susceptibility for the female child later in life. Although expanded clinical trials and preconception trials are required to optimize the potential epigenetic biomarkers, such epigenetic biomarkers may allow preventative medicine strategies to reduce the incidence of preterm birth.

Mid-gestation serum lipidomic profile associations with spontaneous preterm birth are influenced by body mass index

Spontaneous preterm birth (sPTB) is a major cause of infant morbidity and mortality. While metabolic changes leading to preterm birth are unknown, several factors including dyslipidemia and inflammation have been implicated and paradoxically both low (<18.5 kg/m²) and high (>30 kg/m²) body mass indices (BMIs) are risk factors for this condition. The objective of the study was to identify BMI-associated metabolic perturbations and potential mid-gestation serum biomarkers of preterm birth in a cohort of underweight, normal weight and obese women experiencing either sPTB or full-term deliveries (n = 102; n = 17/group). For this purpose, we combined untargeted metabolomics and lipidomics with targeted metabolic profiling of major regulators of inflammation and metabolism, including oxylipins, endocannabinoids, bile acids and ceramides. Women who were obese and had sPTB showed elevated oxidative stress and dyslipidemia characterized by elevated serum free fatty acids. Women who were underweight-associated sPTB also showed evidence of dyslipidemia characterized by elevated phospholipids, unsaturated triglycerides, sphingomyelins, cholesteryl esters and long-chain acylcarnitines. In normal weight women experiencing sPTB, the relative abundance of 14(15)-epoxyeicosatrienoic acid and 14,15-dihydroxyeicosatrienoic acids to other regioisomers were altered at mid-pregnancy. This phenomenon is not yet associated with any biological process, but may be linked to estrogen metabolism. These changes were differentially modulated across BMI groups. In conclusion, using metabolomics we observed distinct BMI-dependent metabolic manifestations among women who had sPTB. These observations suggest the potential to predict sPTB mid-gestation using a new set of metabolomic markers and BMI stratification. This study opens the door to further investigate the role of cytochrome P450/epoxide hydrolase metabolism in sPTB.

Serum Health Biomarkers in African and Asian Elephants: Value Ranges and Clinical Values Indicative of the Immune Response

Simple Summary

Biomarkers are biological molecules found in the blood or other fluids or tissues that can indicate normal or abnormal processes or disease. Developing tools to measure biomarkers that indicate immune function and establishing concentrations observed within a species is an important first step in their use for managing health and understanding disease processes. Here we report assays, observed value ranges, and concentrations during illness or injury for seven immune biomarkers measured in the serum of African and Asian elephants under human care. Concentrations were variable in both clinical and non-clinical samples, but all seven biomarkers were elevated in at least one case and most increased in response to routine vaccination in a single Asian elephant. These tools provide an exciting avenue for monitoring health status and helping diagnose and treat health problems in wildlife species, like elephants.

Abstract

Serum biomarkers indicative of inflammation and disease can provide useful information regarding host immune processes, responses to treatment and prognosis. The aims of this study were to assess the use of commercially available anti-equine reagents for the quantification of cytokines (tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), interleukins (IL) 2, 6, and 10) in African (Loxodonta africana, n = 125) and Asian (Elephas maximus, n = 104) elephants, and alongside previously validated anti-human reagents for acute-phase proteins (serum amyloid A and haptoglobin), calculate species-specific biomarker value ranges. In addition, we used opportunistically collected samples to investigate the concentrations of each biomarker during identified clinical cases of illness or injury, as a first step to understanding what biomarkers may be useful to managing elephant health. Immune biomarkers were each elevated above the calculated species-specific value ranges in at least one clinical case, but due to variability in both clinical and non-clinical samples, only serum amyloid A was significantly higher in clinical compared to non-clinical paired samples, with tendencies for higher TNF-α and IL-10. We also detected increased secretion of serum amyloid A and all five cytokines following routine vaccination of a single Asian elephant, indicating that these biomarkers can be beneficial for studying normal immune processes as well as pathology. This study indicates that assays developed with commercial reagents can be used to quantify health biomarkers in wildlife species and identifies several that warrant further investigation to elucidate immune responses to various pathologies.

Evolving cervical imaging technologies to predict preterm birth

Preterm birth, defined as delivery at less than 37 weeks' gestation, increases maternal-fetal morbidity and mortality and places heavy financial and emotional burdens on families and society. Although premature cervical remodeling is a major factor in many preterm deliveries, how and why this occurs is poorly understood. This review describes existing and emerging imaging techniques and their advantages and disadvantages in assessing cervical remodeling. Brightness mode (B-mode) ultrasound is used to measure the cervical length, currently the gold standard for determining risk of preterm birth. Several new B-mode ultrasound techniques are being developed, including measuring attenuation, cervical gland area, and the cervical consistency index. Shear wave speed can differentiate between soft (ripe) and firm (unripe) cervices by measuring the speed of ultrasound through a tissue. Elastography provides qualitative information regarding cervical stiffness by compressing the tissue with the ultrasound probe. Raman spectroscopy uses a fiber optic probe to assess the biochemical composition of the cervix throughout pregnancy. Second harmonic generation microscopy uses light to quantify changes in collagen fiber structure and size during cervical maturation. Finally, photoacoustic endoscopy records light-induced sound to determine optical characteristics of cervical tissue. In the long term, a combination of several imaging approaches, combined with consideration of clinical epidemiologic characteristics, will likely be required to accurately predict preterm birth.

Elevated body mass index during pregnancy and gestational weight gain in HIV-infected and HIV-uninfected women in Cape Town, South Africa: association with adverse birth outcomes

OBJECTIVES

To examine the association between maternal body mass index (BMI) and gestational weight gain (GWG) and adverse birth outcomes in HIV-infected and HIV-uninfected women.

METHODS

In an urban South African community, 2921 consecutive HIV-infected and HIV-uninfected pregnant women attending primary healthcare services were assessed at their first antenatal visit. A subset of HIV-infected women enrolled in a longitudinal study was assessed three times during pregnancy. All women had birth outcome data from medical records and study questionnaires. In analyses, the associations between BMI, GWG, maternal factors and adverse birth outcomes were assessed with logistic regression models.

RESULTS

The estimated pre-pregnancy BMI median was 29 kg/m2 (IQR, 24-34) overall, 29 kg/m2 (IQR, 24-34) for HIV-uninfected and 28 kg/m2 (IQR, 24-34) for HIV-infected women; HIV prevalence was 38%. In adjusted models, increased BMI in the overall cohort was positively associated with age, haemoglobin and parity at first antenatal visit. Maternal obesity was associated with increased likelihood of having high birthweight (aOR 2.54, 95% CI 1.39-4.66) and large size for gestational age (aOR 1.66, 95% CI 1.20-2.31) infants. In the subset cohort, GWG was associated with increased likelihood of spontaneous preterm delivery (aOR 4.35, 95% CI 1.55-12.21) and high birthweight (aOR 3.00, 95% CI 1.22-7.34) infants.

CONCLUSION

Obesity during pregnancy is prevalent in this setting and appears associated with increased risk of adverse birth outcomes in both HIV-infected and HIV-uninfected women. Weight management interventions targeting women of child-bearing age are needed to promote healthy pregnancies and reduce adverse birth outcomes.

Brief Report: Markers of Spontaneous Preterm Delivery in Women Living With HIV: Relationship With Protease Inhibitors and Vitamin D

BACKGROUND

Women living with HIV (WLHIV) have increased risk of spontaneous preterm delivery (SPTD). We sought to identify plasma predictors of SPTD and their correlations with factors that increase the risk of SPTD, such as vitamin D deficiency and use of protease inhibitors.

DESIGN

Plasma was obtained from 103 WLHIV with SPTD (≤35 weeks gestation) and 205 controls with term deliveries (TDs; ≥37 weeds) matched to cases 2:1 by race and gestational age at blood draw. TNFα, IFNγ, IL6, IL8, IL1β, IL18, IL17, granulocyte colony stimulating factor (GCSF), MCP1, IP10, sIL2Rα, sCD14, vascular endothelial factor a, monocyte colony stimulation factor, GROα, MMP9, IL10, TGFβ, sCTLA4, and eicosanoids were compared between cases adjusting for known SPTD risk factors.

RESULTS

Participants had similar demographic characteristics, but cases had higher plasma HIV RNA, lower CD4 cells, and more advanced HIV disease compared with controls. High sIL2Rα was associated with increased risk of SPTD. High sCD14, GCSF, PGF2α, and 5-HEPE were marginally associated with increased risk of SPTD. Women who initiated protease inhibitors-containing antiretroviral treatment before or during the first trimester had higher levels of GCSF and 5-HEPE compared with women without such exposure before plasma collection. Vitamin D insufficiency was associated with higher inflammatory sCD14 and PGF2α, and lower anti-inflammatory 5-HEPE.

CONCLUSIONS

The best plasma predictor of SPTD in WLHIV was sIL2Rα, a marker of T-cell activation. Markers of monocyte activation and eicosanoids were marginally increased in WLHIV and SPTD, suggesting that they may also play a role in the pathogenesis of this disorder.

Second trimester serum cortisol and preterm birth: an analysis by timing and subtype

OBJECTIVE

We hypothesized second trimester serum cortisol would be higher in spontaneous preterm births compared to provider-initiated (previously termed 'medically indicated') preterm births.

STUDY DESIGN

We used a nested case-control design with a sample of 993 women with live births. Cortisol was measured from serum samples collected as part of routine prenatal screening. We tested whether mean-adjusted cortisol fold-change differed by gestational age at delivery or preterm birth subtype using multivariable linear regression.

RESULT

An inverse association between cortisol and gestational age category (trend p = 0.09) was observed. Among deliveries prior to 37 weeks, the mean-adjusted cortisol fold-change values were highest for preterm premature rupture of the membranes (1.10), followed by premature labor (1.03) and provider-initiated preterm birth (1.01), although they did not differ statistically.

CONCLUSION

Cortisol continues to be of interest as a marker of future preterm birth. Augmentation with additional biomarkers should be explored.

'The obesity paradox': a reconsideration of obesity and the risk of preterm birth

OBJECTIVE

The association between obesity and spontaneous preterm births (sPTBs) has been shown to be influenced by obesity-attendant comorbidities. Our objective was to better understand the complex relationship of obesity and its attendant comorbidities with sPTBs.

STUDY DESIGN

A retrospective analysis utilizing maternally linked hospital and birth certificate records of 2 049 196 singleton California deliveries from 2007 to 2011. Adjusted relative risks (aRRs) for sPTBs were estimated using multivariate Poisson regression modeling.

RESULTS

Obese women had higher aRRs for sPTBs than their normal body mass index (BMI) controls. aRRs (95% confidence interval) increased with increasing BMI category: Obese I=1.10 (1.08 to 1.12); Obese II=1.15 (1.12 to 1.18); and Obese III=1.26 (1.22 to 1.30). When comparing only obese women without comorbidities to their normal BMI controls, aRRs reversed, that is, obese women had lower aRRs of sPTBs: Obese I=0.96 (0.94 to 0.98), Obese II=0.95 (0.91 to 0.98); and Obese III=0.98 (0.94 to 1.03). This same reversal of aRR direction was also observed among women with comorbidities: 0.92 (0.89 to 0.96); 0.89 (0.85 to 0.93); and 0.89 (0.85 to 0.93), respectively. Increasing BMI increased the aRRs for sPTBs among patients with gestational diabetes (P<0.05), while decreasing the risk among patients with chronic hypertension and pregnancy-related hypertensive disease (P<0.05).

CONCLUSIONS

The obesity and preterm birth paradox is an example of what has been described as 'Simpson's Paradox'. Unmeasured confounding factors mediated by comorbidities may explain the observed protective effect of obesity upon conditioning on the presence or absence of comorbidities and thus resolve the paradox.

Epigenetic Biomarkers of Preterm Birth and Its Risk Factors

A biomarker is a biological measure predictive of a normal or pathogenic process or response. Biomarkers are often useful for making clinical decisions and determining treatment course. One area where such biomarkers would be particularly useful is in identifying women at risk for preterm delivery and related pregnancy complications. Neonates born preterm have significant morbidity and mortality, both in the perinatal period and throughout the life course, and identifying women at risk of delivering preterm may allow for targeted interventions to prevent or delay preterm birth (PTB). In addition to identifying those at increased risk for preterm birth, biomarkers may be able to distinguish neonates at particular risk for future complications due to modifiable environmental factors, such as maternal smoking or alcohol use during pregnancy. Currently, there are no such biomarkers available, though candidate gene and epigenome-wide association studies have identified DNA methylation differences associated with PTB, its risk factors and its long-term outcomes. Further biomarker development is crucial to reducing the health burden associated with adverse intrauterine conditions and preterm birth, and the results of recent DNA methylation studies may advance that goal.