Mononuclear leukocyte infiltrate in extraplacental membranes and preterm delivery.

Large numbers of polymorphonuclear leukocytes in the amnion and chorion define histological chorioamnionitis (HCA), a condition linked to spontaneous preterm delivery (PTD). Less is known about placental patterns of mononuclear leukocyte (MNL) density and PTD. In this prospective study (1998-2004), women were sampled from 52 clinics in 5 Michigan communities and enrolled at 16-27 weeks' gestation. HCA and MNL distributions in delivered placentas were evaluated microscopically in a subcohort (290 preterm, 823 term). Midpregnancy biomarkers from maternal blood (i.e., C-reactive protein (CRP), corticotropin-releasing hormone, and cytokines) were compared among term and PTD subjects grouped by presence/absence of HCA and high MNL density. A density of more than 10 MNLs per high-power field in the chorion of the membrane roll, referred to as MNL-CMR, was associated with medically indicated PTD (odds ratio = 2.2, 95% confidence interval: 1.3, 3.6) and spontaneous PTD (odds ratio = 2.5, 95% confidence interval: 1.7, 3.7). Associations persisted after removal of women with HCA-positive placentas, abruption, hypertensive disorders, or obesity. HCA-associated PTD showed higher CRP and cytokine levels. MNL-CMR-associated PTD showed higher CRP and corticotropin-releasing hormone levels. These data suggest that an MNL infiltrate in the chorion of the membrane roll marks PTD pathways that are distinct from HCA and not entirely explained by pregnancy complications.

Inflammation biomarkers in vaginal fluid and preterm delivery.

STUDY QUESTION: Which inflammation biomarkers detected in the vaginal fluid are most informative for identifying preterm delivery (PTD) risk? SUMMARY ANSWER: Elevated interleukin (IL)-6 at mid-trimester was associated with increased odds of spontaneous PTD at <35 weeks and with PTD plus histologic chorioamnionitis (HCA), and had the greatest sensitivity for detecting these two PTD subtypes. WHAT IS KNOWN ALREADY: Maternal and/or fetal inflammation play a role in some preterm deliveries, therefore inflammation biomarkers might help to identify women at greater risk. STUDY DESIGN, SIZE, DURATION: We examined 1115 women from the Pregnancy Outcomes and Community Health Study, a cohort study conducted from September 1998 through June 2004, for whom data were available on mid-pregnancy inflammatory biomarkers. PARTICIPANTS/MATERIALS, SETTING, METHODS: At enrollment at 16-27 weeks gestation, vaginal fluid samples were collected from a swab and 15 eluted biomarkers were measured using the Meso Scale Discovery multiplex electrochemiluminescence platform. Associations of biomarkers with PTD were examined, according to clinical circumstance, week at delivery and presence/absence of HCA. Weighted logistic regression was used to determine odds ratios (OR) and 95% confidence intervals (CI) adjusted for race. Sensitivity and specificity were compared between individual and multiple biomarkers, identified by a bootstrapping method. MAIN RESULTS AND THE ROLE OF CHANCE: Elevated IL-6 (>75th percentile) displayed the strongest association with spontaneous PTD <35 weeks (OR 2.3; CI 1.3-4.0) and PTD with HCA (OR 2.8; CI 1.4-6.0). The sensitivity of IL-6 to detect spontaneous PTD <35 weeks or PTD with HCA was 0.43 and 0.51, respectively, while specificity was 0.74 and 0.75, respectively. IL-6 plus IL1ß, IL-6r, tumor necrosis factor-alpha or granulocyte-macrophage colony-stimulating factor increased specificity (range 0.84-0.88), but decreased sensitivity (range 0.28-0.34) to detect both PTD subtypes. Results were similar when a combination of IL-6 and bacterial vaginosis (BV) was explored. Thus, the use of multiple biomarkers did not detect PTD subtypes with a greater sensitivity than IL-6 alone, and IL-6 is a specific but non-sensitive marker for the detection of spontaneous PTD. LIMITATIONS, REASONS FOR CAUTION: Our ability to find small effect size associations between PTD and inflammation biomarkers (OR <2.0) might have been limited by the modest number of less common PTD subtypes in our population (e.g. spontaneous delivery <35 weeks, PTD accompanied by HCA) and by relatively higher variability for some cytokines, for example tumor necrosis factor-α, IL-12p70, IL-10 and granulocyte-macrophage colony-stimulating factor, that are less stable and commonly undetectable or detectable at low levels in human vaginal secretions. WIDER IMPLICATIONS OF THE FINDINGS: Larger studies are needed to further explore a role of inflammation biomarkers in combination with other risk factors, including specific BV-associated organisms, for the prediction of PTD subtypes. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the National Institute of Child Health and Human Development, National Institute of Nursing, March of Dimes Foundation, Thrasher Research Foundation and Centers for Disease Control and Prevention. The authors have no conflicts of interest.

Maternal lipids at mid-pregnancy and the risk of preterm delivery.

OBJECTIVE: This study examined associations between maternal lipid levels at mid-pregnancy and preterm delivery, medically indicated or spontaneous. DESIGN: Prospective cohort study. SETTING: Women were recruited from 52 clinics in five Michigan, USA communities (1998-2004). POPULATION: Pregnant women were enrolled at 15-27 weeks' gestation and followed to delivery (n=3019). METHODS: A single blood sample was obtained at study enrollment. Blood lipids, i.e. total cholesterol (TC), high-density lipoprotein (HDLc), low-density lipoprotein (LDLc) cholesterol, and triglycerides (TG), were measured on a sub-cohort (n=1309). MAIN OUTCOME MEASURES: There were 221 spontaneous, 100 medically indicated preterm deliveries and 988 term deliveries. Polytomous logistic regression models examined relationships among cholesterol levels (Low: <10(th) percentile, Referent: 10(th) -<70(th) percentile, High: ≥70(th) percentile), quartiles of TG (Referent: first quartile) and delivery outcome (Referent: term). RESULTS: Odds of medically indicated preterm delivery were increased among women with low TC (adjusted odds ratio (aOR)=2.04, 95% confidence interval (CI): 1.12, 3.72), low HDLc (aOR=1.89, 95%CI: 1.04, 3.42) or low LDLc (aOR=1.96, 95%CI: 1.09, 3.54). Odds of spontaneous preterm delivery were increased among women with high TC (aOR=1.51, 95%CI: 1.06, 2.15), high LDLc (aOR=1.42, 95%CI: 0.99, 2.04) or high TG (aOR=1.90, 95%CI: 1.21, 2.97 and aOR=1.72, 95%CI: 1.06, 2.78 for third and fourth quartiles, respectively). CONCLUSIONS: Extremely low TC, HDLc, and LDLc were associated with a modest increase in risk of medically indicated preterm delivery, whereas high TC, LDLc and TG modestly increased the risk of spontaneous preterm delivery. Further research is needed to uncover explanations for these associations and to identify optimal ranges for maternal lipids.

Placental pathology, corticotropin-releasing hormone, timing of parturition, and fetal growth in the pregnancy outcomes and community health study.

Background: Identification of vascular pathologies in delivered placentas and their associations with biomarkers measured during pregnancy may elucidate mechanisms of adverse pregnancy outcomes and inform early detection and intervention strategies.Objectives: To examine associations of placental vascular pathology with birth size and timing of parturition, and to evaluate maternal midpregnancy serum corticotropin-releasing hormone (CRH) levels as a marker of the above associations.Study design: The pregnancy outcomes and community health (POUCH) Study enrolled women at 16-27 weeks of pregnancy from five Michigan communities. Histological assessments of delivered placentas and assays of CRH in maternal blood sampled at enrollment were performed in a subcohort of 1152 participants. Five placental vascular pathology constructs were formulated: Maternal-Vascular-Obstructive (MVO), Fetal Vascular-Obstructive (FVO), Maternal Vascular-disturbance of Integrity (MVI), Fetal Vascular-disturbance of Integrity (FVI), and Maternal Vascular-Developmental (MVD). A four-level outcome variable combined small for gestational (SGA) yes/no and delivery timing preterm/term; the non-SGA/term served as the referent group. In multinomial logistic regression models, the five vascular pathology groups were evaluated in relation to the outcome variable and effect sizes were compared before versus after exclusion of participants with high CRH (top quartile).Results: Adjusted odds ratios (aOR) for MVO among SGA/term and SGA/preterm were 4.1 (95% CI: 2.2, 7.9) and 8.8 (95% CI: 3.3, 23.5) respectively. Among SGA/preterm births, the aOR was attenuated by ∼40%, i.e. 5.4 (95% CI: 1.1, 26.2) after removing high CRH pregnancies. MVI and FVO were each associated with SGA/preterm, aOR = 3.7 (95% CI: 1.3, 10.3) and 10.5 (95% CI: 3.6, 30.8) respectively. Removal of high CRH pregnancies reduced the OR estimates by nearly half, i.e. MVI aOR = 1.9 (95% CI: 0.34, 10.9), FVO aOR = 6.0 (95% CI: 1.3, 28.6). MVI, FVI and MVD were each associated with greater odds of non-SGA/preterm, but the aORs showed little change after removing high CRH pregnancies.Conclusions: Obstructive placental vascular pathologies in maternal or fetal vessels are associated with SGA. High CRH levels coincided with a portion of pregnancies that share these complications, particularly among pregnancies that also ended prematurely.

Polymorphisms in thrombophilia and renin-angiotensin system pathways, preterm delivery, and evidence of placental hemorrhage.

OBJECTIVE: The purpose of this study was to analyze functional polymorphisms in candidate genes (methylenetetrahydrofolate reductase [MTHFR]677C>T, MTHFR1298A>C, factor 5 1691G>A [FVL], and angiotensinogen (AGT)-6G>A) in relation to a hypothesized placental hemorrhage pathway to preterm delivery (PTD). STUDY DESIGN: We assessed maternal genotypes, pregnancy outcomes, and placental pathologic evidence among 560 white and 399 black women who were recruited at mid trimester into a prospective cohort study (1998-2004). Odds of dominant genotypes were calculated for PTDs with (n = 56) or without (n = 177) evidence of placental hemorrhage (referent = term) with the use of race-stratified polytomous logistic regression models. RESULTS: Among white women, FVL GA/AA and AGT(-6) GA/AA were both associated with hemorrhage-related PTDs (odds ratio [OR], 4.8; 95% confidence interval [CI], 1.6-14.2 and OR, 3.8; 95% CI, 1.3-10.5, respectively), but not other PTDs (ORs, 1.2 and 0.9, respectively). FVL GA/AA was associated with placental abruption (OR, 5.8; 95% CI, 1.1-30) among white women. All results were null for MTHFR genotypes. CONCLUSION: FVL and AGT variant genotypes were associated specifically with hemorrhage-related PTDs.

Working Towards a Reproducible Method for Quantifying Placental Syncytial Knots.

Prominent syncytial knots (SK) in placentas signal advanced gestation or placental malperfusion, reflecting exposures that adversely affect placental development and pregnancy outcomes. Molecular-level interrogations of syncytiotrophoblast have altered perceptions of and raised questions about the function and disposition of SK. Quantifying SK and achieving acceptable levels of interrater reliability have been challenging. Our objective was to develop a simple, reproducible protocol for counting SK and demonstrate interrater reliability overall and within 3 parameters, ie, preterm vs term delivery, presence vs absence of diffuse prominent SK (DPSK), and SK relationship with a lesion, all of which could influence measurement reproducibility and interpretation. Criteria for defining SK and a grid system drawn on glass slides were developed for counting percentage of villi with SK. One disc section each from 151 placentas, sampled from 8 groups defined by the 3 parameters, was assessed by 2 pretrained pathologists. The resulting weighted kappa statistic for overall interrater agreement was 0.60 (very good) and Spearman correlation coefficient for ranking quartiles was >0.70. Agreement was best for preterm placentas, kappa  =  0.61, and those only showing DPSK associated with a lesion, kappa  =  0.67. Agreement was low in the absence of DPSK, kappa  =  0.22, or when DPSK was present in a placenta not associated with a lesion, kappa  =  0.32. The proposed method offers a potentially reliable approach for categorizing SK counts as normal vs abnormal or providing continuous measure counts. More extensive pretraining, focused on placentas with few SK and those without an associated lesion, is recommended to improve agreement.

C-reactive protein and preterm delivery: clues from placental findings and maternal weight.

To study the association between maternal C-reactive protein (CRP) and preterm delivery (PTD) pathways, CRP was measured in maternal plasma collected at mid-pregnancy (n = 1310). PTD was subdivided into spontaneous (sPTD) or medically indicated (MI-PTD). Histologic chorioamnionitis (HCA) was determined by placental histopathology (n = 1076). Adjusted CRP levels were elevated for sPTD (5.5 µg/mL) versus term deliveries (4.8 µg/mL) and higher in sPTD with HCA (6.3 µg/mL). After removing HCA, an interaction between body mass index (BMI) and sPTD in relation to CRP was noted. In BMI-stratified models, an association between CRP and sPTD among women with prepregnancy BMI >25 (8.9 µg/mL for sPTD; 7.2 µg/mL for term) was absent among women with lower BMI. We propose that this remaining association in overweight/obese women suggests that CRP may mark an obesity/inflammation PTD pathway that is distinct from the pathway indicated by HCA.

Late-preterm birth by delivery circumstance and its association with parent-reported attention problems in childhood.

OBJECTIVE: Late-preterm birth (LPB, 34-36 wk) has been associated with an increased risk of attention problems in childhood relative to full-term birth (FTB, ≥37 wk), but little is known about factors contributing to this risk. The authors investigated the contributions of clinical circumstances surrounding delivery using follow-up data from the Pregnancy Outcomes and Community Health (POUCH) Study. METHODS: Women who delivered late preterm or full term and completed the sex- and age-referenced Conners' Parent Rating Scales-Short Form: Revised were included in the present analysis (N = 762; children's age, 3-9 y). The Conners' Parent Rating Scales-Short Form: Revised measures dimensions of behavior linked to attention problems, including oppositionality, inattention, hyperactivity, and a global attention problem index. Using general linear models, the authors evaluated whether LPB subtype (medically indicated [MI] or spontaneous) was associated with these dimensions relative to FTB. RESULTS: After adjustment for parity, sociodemographics, child age, and maternal symptoms of depression and serious mental illness during pregnancy and at the child survey, only MI LPB was associated with higher hyperactivity and global index scores (mean difference from FTB = 3.8 [95% confidence interval {CI}: 0.5, 7.0] and 3.1 [95% CI 0.0, 6.2]). These findings were largely driven by children between 6 and 9 years. Removal of women with hypertensive disorders during pregnancy (N = 85) or placental findings related to hypertensive conditions (obstruction, decreased maternal spiral artery conversion; N = 134) reduced the differences below significance thresholds. CONCLUSIONS: Among LPBs, only MI LPB was associated with higher levels of parent-reported childhood attention problems, suggesting that complications motivating medical intervention during the late-preterm period mark increased risk for such problems. Hypertensive disorders seem to play a role in these associations.

Downregulation of H19 improves the differentiation potential of mouse parthenogenetic embryonic stem cells.

Parthenogenetic embryonic stem cells (P-ESCs) offer an alternative source of pluripotent cells, which hold great promise for autologous transplantation and regenerative medicine. P-ESCs have been successfully derived from blastocysts of several mammalian species. However, compared with biparental embryonic stem cells (B-ESCs), P-ESCs are limited in their ability to fully differentiate into all 3 germ layers. For example, it has been observed that there is a differentiation bias toward ectoderm derivatives at the expense of endoderm and mesoderm derivatives-muscle in particular-in chimeric embryos, teratomas, and embryoid bodies. In the present study we found that H19 expression was highly upregulated in P-ESCs with more than 6-fold overexpression compared with B-ESCs. Thus, we hypothesized that manipulation of the H19 gene in P-ESCs would alleviate their limitations and allow them to function like B-ESCs. To test this hypothesis we employed a small hairpin RNA approach to reduce the amount of H19 transcripts in mouse P-ESCs. We found that downregulation of H19 led to an increase of mesoderm-derived muscle and endoderm in P-ESCs teratomas similar to that observed in B-ESCs teratomas. This phenomenon coincided with upregulation of mesoderm-specific genes such as Myf5, Myf6, and MyoD. Moreover, H19 downregulated P-ESCs differentiated into a higher percentage of beating cardiomyocytes compared with control P-ESCs. Collectively, these results suggest that P-ESCs are amenable to molecular modifications that bring them functionally closer to true ESCs.