Karen K. Mestan

Differential Patterns of 27 Cord Blood Immune Biomarkers Across Gestational Age

OBJECTIVES. Inflammation has been associated with preterm delivery and adverse neonatal outcomes such as cerebral palsy and chronic lung disease. However, no study to date has simultaneously examined a wide range of inflammatory mediators and their relationship to gestational age. We sought to describe the distribution of immune biomarkers in cord blood across gestational age and to investigate the association between biomarker level patterns and preterm birth. PATIENTS AND METHODS. As part of a large-scale molecular epidemiological study of preterm birth conducted at Boston Medical Center, this study analyzed both clinical and biomarker data from 927 births. Twenty-seven biomarkers were simultaneously quantified by immunoassay. The associations between the quartiles of 27 biomarkers and 3 gestational groups (≤32, 33–36, and ≥37 weeks) were analyzed. Biomarkers found to be significant were further analyzed for dose-response correlation with preterm birth by logistic regression, adjusted for pertinent demographic and clinical factors. RESULTS. The 27 biomarkers could be classified into 1 of 3 groups: (1) biomarkers increased in preterm birth (interleukin [IL]-2, IL-4, IL-5, IL-8, IL-10, monocyte chemoattractant protein 1, macrophage inflammatory protein [MIP]-1α, MIP-1β, soluble IL-6 receptor α, tumor necrosis factor α, soluble tumor necrosis factor receptor I, and TREM-1 [triggering receptor expressed on myeloid cells 1]); (2) biomarkers decreased in preterm birth (brain-derived neurotrophic factor, IL-1β, IL-18, matrix metalloproteinase 9, and neurotrophin 3); and (3) biomarkers not associated with preterm birth (IL-6, IL-12, IL-17, granulocyte/macrophage colony-stimulating factor, interferon γ, macrophage migration inhibitory factor, neurotrophin 4, RANTES [regulated on activation, normal T-cell expressed and secreted], transforming growth factor β, and tumor necrosis factor β). CONCLUSIONS. Biomarkers have different directions of association with prematurity; for significant biomarkers, the strength of association increases with biomarker concentration. Our results provide important information that could be used to guide additional studies aimed at determining mechanisms that contribute to preterm birth.

Fetal growth restriction and pulmonary hypertension in premature infants with bronchopulmonary dysplasia

Objective:To identify the association between birth weight (BW)-for-gestational age (GA) and pulmonary hypertension (PHTN) at 36 weeks in infants with moderate–severe bronchopulmonary dysplasia (BPD).Study Design:In this retrospective cohort study, we followed 138 premature infants (⩽28 weeks) with moderate and severe BPD (National Institutes of Health consensus definition) born at Prentice Women’s Hospital between 2005 and 2009. BW percentiles were calculated using the Fenton growth curve for premature infants. PHTN was determined using a standardized algorithm of echocardiogram review at 36 weeks. Logistic regression was used to evaluate the associations between BW percentile subgroups and PHTN, taking into account antenatal and neonatal factors that were related to PHTN.Result:PHTN was associated with small BW-for-GA, ranging from thresholds of <10th to <25th percentile (P<0.001). These associations remained significant when comparing BW <25th percentile to the reference group (50 to 89th percentile); after adjustment for GA, gender, multiple gestation, race/ethnicity (odds ratio (OR)=4.2; 95% confidence interval (CI)=1.5, 12.1); and after further adjustment for maternal vascular disease, intrauterine infection, oligohydramnios and relevant postnatal factors (OR=5.7; 95% CI=1.5, 21.2). Longitudinal follow-up of this cohort showed a trend toward higher morbidity and death among PHTN infants with BW <25th percentile.Conclusion:BW-for-GA is an important predictor of PHTN in premature infants with moderate–severe BPD. Our findings contribute to the growing evidence supporting fetal mechanisms of later onset pulmonary vascular disease.

Pulmonary hypertension in bronchopulmonary dysplasia

Pulmonary hypertension (PH) is a common complication of neonatal respiratory diseases, including bronchopulmonary dysplasia (BPD), and recent studies have increased awareness that PH worsens the clinical course, morbidity and mortality of BPD. Recent evidence indicates that up to 18% of all extremely low-birth-weight infants will develop some degree of PH during their hospitalization, and the incidence rises to 25-40% of the infants with established BPD. Risk factors are not yet well understood, but new evidence shows that fetal growth restriction is a significant predictor of PH. Echocardiography remains the primary method for evaluation of BPD-associated PH, and the development of standardized screening timelines and techniques for identification of infants with BPD-associated PH remains an important ongoing topic of investigation. The use of pulmonary vasodilator medications, such as nitric oxide, sildenafil, and others, in the BPD population is steadily growing, but additional studies are needed regarding their long-term safety and efficacy.

Maternal preconception body mass index and offspring cord blood DNA methylation: Exploration of early life origins of disease

Maternal obesity is associated with a variety of common diseases in the offspring. One possible underlying mechanism could be maternal obesity induced alterations in DNA methylation. However, this hypothesis is yet to be tested. We performed epigenomic mapping of cord blood among 308 Black mother‐infant pairs delivered at term at the Boston Medical Center using the Illumina HumanMethylation27 BeadChip. Linear regression and pathway analyses were conducted to evaluate the associations between DNA methylation levels and prepregnancy maternal BMI (<25, 25–30, ≥30 kg/m2). The methylation levels of 20 CpG sites were associated with maternal BMI at a significance level of P‐value <10−4 in the overall sample, and boys and girls, separately. One CpG site remained statistically significant after correction for multiple comparisons (FDR corrected P‐value = 0.04) and was annotated to a potential cancer gene, ZCCHC10. Some of the other CpG site annotated genes appear to be critical to the development of cancers and cardiovascular diseases (i.e., WNT16, C18orf8, ANGPTL2, SAPCD2, ADCY3, PRR16, ERBB2, DOK2, PLAC1). Significant findings from pathway analysis, such as infectious and inflammatory and lipid metabolism pathways, lends support for the potential impact of maternal BMI on the above stated disorders. This study demonstrates that prepregnancy maternal BMI might lead to alterations in offspring DNA methylation in genes relevant to the development of a range of complex chronic diseases, providing evidence of trans‐generational influence on disease susceptibility via epigenetic mechanism. Environ. Mol. Mutagen. 55:223–230, 2014.

Placental Inflammatory Response Is Associated With Poor Neonatal Growth: Preterm Birth Cohort Study

OBJECTIVE: We sought to determine whether placental markers of intrauterine inflammation were associated with poor weight gain among premature infants in the neonatal period. METHODS: We reviewed 697 preterm births prospectively enrolled as part of an ongoing molecular epidemiological study. Placental markers and serial weight gain were analyzed for premature infants who were hospitalized for ≥21 days (N = 256). Placentas were examined for maternal inflammatory response (MIR), defined as subchorionitis, chorioamnionitis, deciduitis, or free membranitis, and fetal inflammatory response (FIR), defined as inflammation extending to the umbilical cord or chorionic plate. Multivariate linear regression and stratified analyses were performed. RESULTS: Decreases in weight gain at day 21 were associated with the presence of either MIR or FIR (β coefficient = −4.63 ± 1.41; P = .001). The association was stronger with FIR than MIR (P for trend = .0027) and persisted in the remaining hospitalized infants at day 28 (n = 223; β coefficient = −5.53 ± 1.85; P = .0028). Mean body weights were similar among the 3 groups by corrected age of 36 weeks or discharge, whichever came first. Associations between placental inflammation and poor growth persisted among infants with prenatal corticosteroid exposure and/or neonatal complications and remained marginally significant in the nonexposed groups. Among infants without intrauterine growth restriction, significant association persisted (n = 186; β coefficient = −5.68 ± 1.56; P = .0003). CONCLUSIONS: Placental inflammation is associated with poor neonatal growth. MIR and FIR may be useful markers for identifying infants at risk for postnatal growth failure.

Placental pathologic changes of maternal vascular underperfusion in bronchopulmonary dysplasia and pulmonary hypertension

INTRODUCTION Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease of infancy, and BPD-associated pulmonary hypertension (PH) is a serious complication that can negatively impact later childhood health. There is growing evidence that lung injury leading to BPD and PH is due to chronic fetal hypoxia-ischemia. The purpose of this study was to investigate whether placental pathologic changes of maternal vascular underperfusion (MVU) are associated with BPD, and further increased with PH. METHODS We conducted a 5-year retrospective cohort study of premature infants born ≤28 weeks. BPD was defined as persistent oxygen requirement at 36 weeks corrected gestational age. PH was identified using a standardized algorithm of echocardiogram review. Archived placental slides underwent standardized masked histopathologic review. Logistic regression modeling was performed, taking into account important maternal and infant covariates. RESULTS Among 283 births, 121 had MVU, of which 67 (55%) developed BPD, and 24 (20%) had PH. Among the common neonatal complications of extreme prematurity, BPD was the only outcome that was increased with MVU (P < 0.001). After adjustment for birth weight, fetal growth restriction, preeclampsia and other factors, infants with MVU were more likely to develop BPD (adjusted odds ratio = 2.6; 95% confidence interval = 1.4, 4.8). Certain MVU sublesions (fibrinoid necrosis/acute atherosis and distal villous hypoplasia/small terminal villi) were increased with PH (P < 0.001). DISCUSSION Placental MVU may identify BPD infants who were exposed to intrauterine hypoxia-ischemia, which increases their risk for development of PH disease. CONCLUSIONS Our findings have important implications for providing earlier and more effective therapies for BPD.

Cord blood biomarkers of the fetal inflammatory response

Objective. In current, neonatal practice, clinical signs of intrauterine infection (IUI) are often non-specific. From a large panel of immune biomarkers, we seek to identify cord blood markers that are most strongly associated with the fetal inflammatory response (FIR), a specific placental lesion associated with serious neonatal complications. Methods. We used multiplex immunoassay to measure 27 biomarkers, selected as part of an NIH-funded study of preterm birth, according to gestational age (GA) and extent of placental inflammation: involvement of chorion, amnion, decidua (maternal inflammatory response, MIR); extension to umbilical cord or chorionic plate (FIR). We used false-discovery rate (FDR < 5%, P < 0.001) to account for multiple comparisons. Results. Among 506 births (GA 23–42 weeks), IL-1β increased with FIR among preterm subgroups (P = 0.0001 for <32 weeks; P = 0.0009 for 33–36 weeks). IL-6 and IL-8 increased with FIR among preterm and full-term infants (P < 0.0001). P-trend for IL-6 and IL-8 with MIR versus FIR was <0.0001. Comparison with respect to clinical IUI yielded persistent elevation with FIR even when clinical signs were absent. The remaining 24 markers were not significantly associated. Conclusion. We conclude that among 27 cord blood biomarkers, IL-1β, IL-6 and IL-8 are selectively associated with FIR. These markers may be clinically useful indicators of extensive IUI associated with poor neonatal outcome.

Flow Cytometry Reveals Similarities Between Lung Macrophages in Humans and Mice.

Findings in murine models implicate subpopulations of alveolar macrophages in the pathogenesis of lung injury and fibrosis, however, the relevance of these findings for humans with chronic lung disease is unknown in part due to a lack of proper tools to identify macrophage heterogeneity in the human lung. Here we report a flow cytometry protocol that allows unambiguous identification of alveolar macrophages, interstitial macrophages and monocytes in the human lung and in bronchoalveolar lavage fluid. We validated this panel using normal lung tissue and tissue from patients with COPD and lung fibrosis. We found evidence of heterogeneity within human alveolar macrophage populations, which suggest parallels between murine and human macrophage development and differentiation. Abstract word count: 113.

Impact of clinical and histologic correlates of maternal and fetal inflammatory response on gestational age in preterm births

Objective. To evaluate the impact of clinical and histopathologic correlates related to maternal and fetal inflammatory responses (MIR and FIR) on degree of preterm birth. Methods. Pathology reports and clinical data from 577 singleton preterm births (<37 weeks of gestation) that took place between 1998 and 2004 were analyzed according to decreasing gestational age (≥33 weeks, 29–32 weeks, and <29 weeks). MIR was defined by presence of subchorionitis, chorioamnionitis, deciduitis, or free membranitis; FIR was defined by presence of funisitis or chorionic plate vasculitis. The associations between MIR alone and MIR with FIR and gestational age subgroups were assessed using logistic regression. Results. The presence of FIR in addition to MIR was more strongly associated with degree of prematurity than the presence of MIR alone, especially for those born at <29 weeks (OR = 10.1 (95% CI 4.3–23.7) and OR = 5.3 (95% CI 2.3–12.5), respectively). These associations remained significant after adjusting for maternal race, clinical signs of chorioamnionitis, medically indicated birth, and intrapartum corticosteroid, tocolysis and antibiotic use, and after stratification by clinical signs of chorioamnionitis and medically indicated birth. Conclusions. The combined presence of MIR and FIR is associated with a higher risk of extreme preterm birth (<29 weeks) than MIR alone, suggesting a contributory role of FIR in the pathophysiology of preterm birth.

Genomic sequencing in clinical trials

Human genome sequencing is the process by which the exact order of nucleic acid base pairs in the 24 human chromosomes is determined. Since the completion of the Human Genome Project in 2003, genomic sequencing is rapidly becoming a major part of our translational research efforts to understand and improve human health and disease. This article reviews the current and future directions of clinical research with respect to genomic sequencing, a technology that is just beginning to find its way into clinical trials both nationally and worldwide. We highlight the currently available types of genomic sequencing platforms, outline the advantages and disadvantages of each, and compare first- and next-generation techniques with respect to capabilities, quality, and cost. We describe the current geographical distributions and types of disease conditions in which these technologies are used, and how next-generation sequencing is strategically being incorporated into new and existing studies. Lastly, recent major breakthroughs and the ongoing challenges of using genomic sequencing in clinical research are discussed.