Genetics of the cervix in relation to preterm birth

Design of hypoxia responsive CRISPR-Cas9 for target gene regulation

The CRISPR-Cas9 system is a widely used gene-editing tool, offering unprecedented opportunities for treating various diseases. Controlling Cas9/dCas9 activity at specific location and time to avoid undesirable effects is very important. Here, we report a conditionally active CRISPR-Cas9 system that regulates target gene expression upon sensing cellular environmental change. We conjugated the oxygen-sensing transcription activation domain (TAD) of hypoxia-inducing factor (HIF-1α) with the Cas9/dCas9 protein. The Cas9-TAD conjugate significantly increased endogenous target gene cleavage under hypoxic conditions compared with that under normoxic conditions, whereas the dCas9-TAD conjugate upregulated endogenous gene transcription. Furthermore, the conjugate system effectively downregulated the expression of SNAIL, an essential gene in cancer metastasis, and upregulated the expression of the tumour-related genes HNF4 and NEUROD1 under hypoxic conditions. Since hypoxia is closely associated with cancer, the hypoxia-dependent Cas9/dCas9 system is a novel addition to the molecular tool kit that functions in response to cellular signals and has potential application for gene therapeutics.

Study protocol to quantify the genetic architecture of sonographic cervical length and its relationship to spontaneous preterm birth

INTRODUCTION

A short cervix (cervical length <25 mm) in the midtrimester (18-24 weeks) of pregnancy is a powerful predictor of spontaneous preterm delivery. Although the biological mechanisms of cervical change during pregnancy have been the subject of extensive investigation, little is known about whether genes influence the length of the cervix, or the extent to which genetic factors contribute to premature cervical shortening. Defining the genetic architecture of cervical length is foundational to understanding the aetiology of a short cervix and its contribution to an increased risk of spontaneous preterm delivery.

METHODS/ANALYSIS

The proposed study is designed to characterise the genetic architecture of cervical length and its genetic relationship to gestational age at delivery in a large cohort of Black/African American women, who are at an increased risk of developing a short cervix and delivering preterm. Repeated measurements of cervical length will be modelled as a longitudinal growth curve, with parameters estimating the initial length of the cervix at the beginning of pregnancy, and its rate of change over time. Genome-wide complex trait analysis methods will be used to estimate the heritability of cervical length growth parameters and their bivariate genetic correlation with gestational age at delivery. Polygenic risk profiling will assess maternal genetic risk for developing a short cervix and subsequently delivering preterm and evaluate the role of cervical length in mediating the relationship between maternal genetic variation and gestational age at delivery.

ETHICS/DISSEMINATION

The proposed analyses will be conducted using deidentified data from participants in an IRB-approved study of longitudinal cervical length who provided blood samples and written informed consent for their use in future genetic research. These analyses are preregistered with the Center for Open Science using the AsPredicted format and the results and genomic summary statistics will be published in a peer-reviewed journal.

COL1A1, COL4A3, TIMP2 and TGFB1 polymorphisms in cervical insufficiency

OBJECTIVES

To investigate the association between selected single nucleotide polymorphisms (SNPs) with cervical insufficiency and its relationship with obstetric history.

METHODS

Twenty-eight women with cervical insufficiency (case group) and 29 non-pregnant women (control group) were included. The SNPs sequenced included rs2586490 in collagen type I alpha 1 chain (COL1A1), rs1882435 in collagen type IV alpha 3 chain (COL4A3), rs2277698 in metallopeptidase inhibitor 2 (TIMP2), and rs1800468 in transforming growth factor beta 1 (TGFB1).

RESULTS

We found a higher frequency of the normal allele in the control group (65.5%) and the homozygous mutated genotype in the case group (64.3%) for rs2586490 in COL1A1 (p=0.023). An unplanned finding in the cervical insufficiency group was a higher gestational age of delivery (median≥38 weeks) in the mutated allele than in the wild-type genotype (median of 28.2 weeks) for rs2857396, which is also in the COL1A1 gene (p=0.011).

CONCLUSIONS

The findings of the present study corroborate the hypothesis that cervical insufficiency has a genetic component and probably involves genes encoding proteins in the extracellular matrix, in addition to inflammatory processes.

High preterm birth at Cipto Mangunkusumo Hospital as a national referral hospital in Indonesia

Background: Preterm birth is the leading direct that causes neonatal death. Indonesia was listed as one of the countries with the greatest number of preterm birth in 2010. This study aims to identify the prevalence and the potential risk factors of preterm birth among women underwent delivery in Cipto Mangunkusumo Hospital, an Indonesian national reference hospital.Methods: This retrospective cohort study involved 2,612 women who delivered between January and December 2013. Any clinical data which related to the potential risk factors and outcomes were recorded. The data were managed using chi-square for bivariate analysis and t-test or Mann-Whitney for numerical data followed by multiple logistic regression for multivariate analysis in SPSS version 20.0.Results: Preterm birth affected 1,020 of 2,616 pregnancies (38.5%). Non-booked patients increased nearly twice risk for preterm delivery (OR 1.89, 95% CI 1.37–2.61). While women with singleton pregnancy (OR 0.17, 95% CI 0.12–0.25), head presentation (OR 0.75, 95% CI 0.63–0.89), and regular ANC (OR 0.67, 95% CI 0.54–0.84) had lower risk for preterm birth. Apgar score, birthweight, and mode of delivery were significantly different between the pre-term group and the full-term group.Conclusion: Prevalence of preterm birth in Cipto Mangunkusumo Hospital was approximately 2.5 times higher compared to the national number. Several factors reducing preterm birth rate include singleton pregnancy, head presentation, and regular ANC.

Racial and social predictors of longitudinal cervical measures: the Cervical Ultrasound Study

OBJECTIVE

To evaluate whether the racial and socioeconomic disparities are present in adverse cervical parameters, and, if so, when such disparities develop.

STUDY DESIGN

A prospective cohort study was conducted. 175 women with a prior preterm birth had up to four endovaginal ultrasounds between gestational weeks 16 and 24 (Cervical Ultrasound Trial of the MFMU). Each sociodemographic factor (race/ethnicity, marital status, insurance funding and education) was examined as a predictor of short cervix or U/funnel shape, using multiple logistic and linear regression. Changes in the cervical length and shape across pregnancy and after pressure were also examined.

RESULTS

The strongest associations were seen between race and government-funded insurance and short cervix and U shape per funneling (race and length <25 mm per funnel: adjusted odds ratio (OR) 5.52, 2.24 to 13.63; government-funded insurance and length <30 mm per funnel: adjusted OR 3.10, 1.34 to 7.15). Changes in cervical length were not associated with sociodemographics.

CONCLUSION

African-American race and, to a lesser extent, insurance funder, are associated with cervical length and shapes that have been associated with preterm birth, and those properties are present largely early in pregnancy.

The association of beta-2 adrenoceptor genotype with short-cervix mediated preterm birth: a case-control study

OBJECTIVE

To determine whether β2 -adrenoceptor (β2 AR) genotype is associated with shortening of the cervix or with preterm birth (PTB) risk among women with a short cervix in the second trimester.

DESIGN

A case-control ancillary study to a multicentre randomised controlled trial.

SETTING

Fourteen participating centres of the Maternal-Fetal Medicine Units Network of the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

POPULATION

Four hundred thirty-nine women, including 315 with short cervix and 124 with normal cervical length.

METHODS

Nulliparous women with cervical length <30 mm upon a 16-22-week transvaginal sonogram and controls frequency-matched for race/ethnicity with cervical lengths ≥40 mm were studied. β2 AR genotype was determined at positions encoding for amino acid residues 16 and 27.

MAIN OUTCOME MEASURES

Genotype distributions were compared between case and control groups. Within the short cervix group, pregnancy outcomes were compared by genotype, with a primary outcome of PTB <37 weeks.

RESULTS

Genotype data were available at position 16 for 433 women and at position 27 for 437. Using a recessive model testing for association between short cervix and genotype, and adjusted for ethnicity, there was no statistical difference between cases and controls for Arg16 homozygosity (OR 0.7, 95% CI 0.4-1.3) or Gln27 homozygosity (OR 0.9, 95% CI 0.3-2.7). Among cases, Arg16 homozygosity was not associated with protection from PTB or spontaneous PTB. Gln27 homozygosity was not associated with PTB risk, although sample size was limited.

CONCLUSIONS

β2 AR genotype does not seem to be associated with short cervical length or with PTB following the second-trimester identification of a short cervix. Influences on PTB associated with β2 AR genotype do not appear to involve a short cervix pathway.

Characteristics of systemic hypertension in preterm children

The prevalence of essential hypertension (EH) among preterm children is unknown. The authors evaluated consecutive children with a diagnosis of hypertension and prematurity (gestational age <37 weeks) in a tertiary pediatric hypertension clinic and identified 36 preterm hypertensive children. Among these preterm children, 23 were diagnosed in the neonatal intensive care unit (NICU; infantile) and 13 were diagnosed at an older age (childhood). When compared with patients with a childhood diagnosis, patients with an infantile diagnosis had a significantly lower gestational age, longer duration of hospitalization in the NICU, and a higher incidence of perinatal risk factors for hypertension. None with infantile diagnosis had EH, whereas 46% with childhood diagnosis had EH. Among premature children, systemic hypertension was either diagnosed in infancy or in childhood, with each age at diagnosis having unique risk factors and clinical course. Although 83% of preterm children had secondary hypertension, EH was diagnosed in 17% and was only seen in those diagnosed beyond infancy.

Oxidative status shifts in uterine cervical incompetence patients

Uterine cervical incompetence (UCI) is a pregnancy complication affecting about 10% of the pregnancies in the western world. Studying the etiology of the UCI requires a specific approach adequate for this highly heterogenous syndrome. Oxidative status disorders are associated with various pathologies, including pregnancy complications. As such, general oxidative status profiling is a promising methodology to treat UCI. We aimed at assaying the closely interrelated oxidative status markers in the uterine cervical incompetence patients by means of the systems biology-oriented approach. Chemiluminescent assay, circulating thioredoxin 1 protein, uric acid, and homocysteine level measurements were used to assess the character of the oxidative status regulation in the UCI patients. We found UCI to be associated with the atypical plasma oxidative status deregulation; UCI plasma samples demonstrated lowered proneness to the pro-oxidative processes, and this was not due to the excessive antioxidant activity. There were neither signs of oxidative stress nor destructive pro-oxidant feedforward circuit locking in the UCI group. We also report increased circulating levels of uric acid in the UCI patients.

Health disparities in risk for cervical insufficiency

BACKGROUND

The purpose of the study was to examine racial/ethnic differences in cervical insufficiency risk.

METHODS

We used the US 2005 Natality data file. Analysis was limited to singleton births. The prevalence of cervical insufficiency was examined by the maternal characteristic for each racial group. Unconditional logistic regression modeling was used to assess the association between race and cervical insufficiency while controlling for confounders.

RESULTS

Cervical insufficiency risk for Black women was more than twice that for their White counterparts [odds ratio (OR) (95% confidence interval (CI)) of 2.45 (2.22–2.71)]. Prior pregnancy termination showed a dose–response relationship with cervical insufficiency. Compared with women with no history of prior pregnancy termination, primiparous women who have had one pregnancy termination had an OR (95% CI) of 2.49 (2.23–2.77). The OR for two, three and four or more terminations were 4.66 (4.07–5.33), 8.07 (6.77–9.61) and 12.36 (10.19–15.00), respectively. Other predictors of cervical insufficiency included previous preterm birth, parity, marital status, renal disease, history of diabetes, polyhydramnios and anemia.

CONCLUSIONS

There were significant racial/ethnic disparities with Black women having increased cervical insufficiency risk, independent of other studied factors. Prior pregnancy termination is also a major risk factor for cervical insufficiency. The White/Black disparity is evident in both primiparous and multiparous women.