Maternal pregnancy-induced hypertension increases subsequent neonatal necrotizing enterocolitis risk: A nationwide population-based retrospective cohort study in Taiwan

Effects of hypertensive disorders of pregnancy on the complications in very low birth weight neonates

OBJECTIVE

This study was designed to investigate the effects of hypertensive disorders of pregnancy (HDP) on the complications in very low birth weight (VLBW) neonates.

METHODS

We retrospectively included VLBW neonates (<37 weeks) who were delivered by HDP pregnant women with a body weight of < 1,500 g (HDP group) hospitalized in our hospital between January 2016 and July 2021. Gestational age matched VLBW neonates delivered by pregnant women with a normal blood pressure, with a proportion of 1:1 to the HDP group in number, served as normal control.

RESULTS

Then we compared the peripartum data and major complications between HDP group and control. The body weight, prelabor rupture of membrane (PROM), maternal age, cesarean section rate, fetal distress, small for gestational age (SGA), mechanical ventilation, RDS, necrotizing enterocolitis (NEC) (≥2 stage), Apgar score at 1 min, and mortality in HDP group showed statistical differences compared with those of the control (all p < 0.05). To compare the major complications among HDP subgroups, we classified the VLBW neonates of the HDP group into three subgroups including gestational hypertension group (n = 72), pre-eclampsia (PE) group (n = 222), and eclampsia group (n = 14), which showed significant differences in the fetal distress, Apgar score at 1 min, SGA, ventilation, RDS and NEC (≥2 stage) among these subgroups (all p < 0.05). Multivariate regression analysis showed that eclampsia and PE were the independent risk factors for SGA and NEC, respectively.

CONCLUSION

HDP was associated with increased incidence of neonatal asphyxia, fatal distress, SGA, mechanical ventilation, RDS, NEC and mortality. Besides, eclampsia and PE were independent risk factors for SGA and NEC.

Effects of hypertension and use of antihypertensive drugs in pregnancy on the risks of childhood cancers in Taiwan

BACKGROUND

Childhood cancers are associated with high mortality and morbidity, and some maternal prescription drug use during pregnancy has been implicated in cancer risk. There are few studies on the effects of hypertension, preeclampsia, and the use of antihypertensives in pregnancy on children's cancer risks.

OBJECTIVE

This population-based cohort study analyzed the relationship between hypertension, preeclampsia, and antihypertensives taken during pregnancy and the risks of childhood cancers in the offspring.

METHODS

Data on all children born in Taiwan between 2004 and 2015 (N = 2,294,292) were obtained from the Maternal and Child Health Database. This registry was linked with the National Health Insurance Database and Cancer Registry to get the records of maternal use of diuretics or other antihypertensives in pregnancy and records of children with cancer diagnosed before 13 years. We used Cox proportional hazard modeling to estimate the influence of maternal health conditions and antihypertensive drug exposure on the risks of developing childhood cancers.

RESULTS

Offspring of mothers with hypertension (chronic or gestational) had a higher risk of acute lymphocytic lymphoma [hazard ratio (HR) = 1.87, 95% Confidence Interval (CI) 1.32 - 2.65] and non-Hodgkin's lymphoma (HR = 1.96, 95% CI 1.34 - 2.86). We estimated only a weak increased cancer risk in children whose mothers used diuretics (HR = 1.16, 95% CI 0.77 - 1.74) or used antihypertensives other than diuretics (HR = 1.15, 95% CI 0.86 - 1.54) before birth.

CONCLUSIONS

In this cohort study, children whose mothers had chronic and gestational hypertension had an increased risk of developing childhood cancer.

Risk factors of necrotizing enterocolitis among neonates admitted to the neonatal intensive care unit at the selected public hospitals in southern Ethiopia, 2023

Introduction

Necrotizing enterocolitis (NEC) is a serious intestinal condition characterized by ischemic necrosis of the intestinal mucosa, inflammation, and invasion by gas-forming organisms, posing a significant threat to neonatal health. Necrotizing enterocolitis remains a significant cause of neonatal morbidity and mortality, particularly in developing countries. Due to limited research conducted in Ethiopia and the study area, there is a lack of information regarding the risk factors associated with necrotizing enterocolitis. Therefore, the goal of this study is to fill the aforementioned gap.

Objective

This study aims to identify the risk factors of necrotizing enterocolitis among neonates admitted to the neonatal intensive care unit (NICU) at selected general and referral hospitals in southern Ethiopia in the year 2023.

Methods and materials

A facility-based unmatched case-control study was conducted. All neonates admitted to the NICU and diagnosed with necrotizing enterocolitis by the attending physician during the data collection period were considered as cases, whereas neonates admitted to the NICU but not diagnosed with necrotizing enterocolitis during the data collection period were considered as controls. Data were collected through face-to-face interviews and record reviews using the Kobo toolbox platform. The binary logistic regression method was used to determine the relationship between a dependent variable and independent variables. Finally, a p-value of < 0.05 was considered statistically significant.

Results

This study included 111 cases and 332 controls. Normal BMI [AOR = 0.11, 95% CI: (0.02, 0.58)], history of khat chewing [AOR = 4.21, 95% CI: (1.96, 9.06)], term gestation [AOR = 0.06, 95% CI: (0.01, 0.18)], history of cigarette smoking [AOR = 2.86, 95% CI: (1.14, 7.14)], length of hospital stay [AOR = 3.3, 95% CI: (1.43, 7.67)], and premature rupture of membrane [AOR = 3.51, 95% CI: (1.77, 6.98)] were significantly associated with NEC.

Conclusion

The study identified several risk factors for necrotizing enterocolitis, including body mass index, history of khat chewing, gestational age, history of cigarette smoking, length of hospital stays, and premature rupture of membrane. Therefore, healthcare providers should be aware of these risk factors to identify newborns at high risk and implement preventive measures.

Comparison of clinical outcomes between active and permissive blood pressure management in extremely preterm infants

Background

There remains uncertainty about the definition of normal blood pressure (BP), and when to initiate treatment for hypotension for extremely preterm infants. To determine the short-term outcomes of extremely preterm infants managed by active compared with permissive BP support regimens during the first 72 hours of life.

Method

This is a retrospective medical records review of 23 +0-28 +6 weeks' gestational age (GA) infants admitted to neonatal units (NNU) with active BP support (aimed to maintain mean arterial BP (MABP) >30 mmHg irrespective of the GA) and permissive BP support (used medication only when babies developed signs of hypotension) regimens. Babies admitted after 12 hours of age, or whose BP data were not available were excluded.

Results

There were 764 infants admitted to the participating hospitals; 671 (88%) were included in the analysis (263 active BP support and 408 permissive BP support). The mean gestational age, birth weight, admission temperature, clinical risk index for babies (CRIB) score and first haemoglobin of infants were comparable between the groups. Active BP support group infants had consistently higher MABP and systolic BP throughout the first 72 hours of life (p<0.01). In the active group compared to the permissive group 56 (21.3%) vs 104 (25.5%) babies died, and 21 (8%) vs 51 (12.5%) developed >grade 2 intra ventricular haemorrhage (IVH). Death before discharge (adjusted OR 1.38 (0.88 - 2.16)) or IVH (1.38 (0.96 - 1.98)) was similar between the two groups. Necrotising enterocolitis (NEC) ≥stage 2 was significantly higher in permissive BP support group infants (1.65 (1.07 - 2.50)).

Conclusions

There was no difference in mortality or IVH between the two BP management approaches. Active BP support may reduce NEC. This should be investigated prospectively in large multicentre randomised studies.

Impact of hypertensive disorders of pregnancy on neonatal outcomes among infants born at 24+0-31+6 weeks' gestation in China: A multicenter cohort study

Objective

To describe the rate of hypertensive disorder of pregnancy (HDP) among mothers of very preterm infants (VPIs) admitted to Chinese neonatal intensive care units (NICUs), and to investigate the relationship between HDP and the outcomes of VPIs.

Study design

Cohort study of all VPIs born at a gestational age of 24+0-31+6 weeks and admitted to 57 tertiary NICUs of the Chinese Neonatal Network (CHNN) in 2019. Infants with severe congenital anomalies or missing maternal HDP information were excluded. Two multivariate logistic regression models were generated to assess the relationship between HDP and neonatal outcomes.

Results

Among 9,262 infants enrolled, 1,744 (18.8%) infants were born to mothers with HDP, with an increasing incidence with increasing gestational age. VPIs born to mothers with HDP had higher gestational age but lower birth weight and were more likely to be small for gestational age. Mothers with HDP were more likely to receive antenatal steroids, MgSO4 and cesarean section. Infants in the HDP group showed higher observed rates of mortality or any morbidity than infants in the non-HDP group (50.2% vs. 47.2%, crude odds ratio (OR) 1.13, 95% CI 1.02-1.26). However, the associations between HDP and adverse outcomes were not significant after adjustment. In the HDP group, mothers of 1,324/1,688 (78.4%) infants were diagnosed with preeclampsia/eclampsia. Infants born to mothers with preeclampsia/eclampsia had significantly lower odds of early death and severe retinopathy of prematurity.

Conclusions

Nearly one-fifth of VPIs were born to mothers with HDP in Chinese NICUs. No significant association was identified between HDP and adverse neonatal short-term outcomes of VPIs, while long-term follow-up of these infants is needed.

Impact of maternal factors, environmental factors, and race on necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a complex disease with a multifactorial etiology. As the leading cause of intestinal morbidity and mortality among premature infants, many resources are being dedicated to neonatal care and molecular targets in the newborn intestine. However, NEC is heavily influenced by maternal and perinatal factors as well. Given its nature, preventive approaches to NEC are more likely to improve outcomes than new treatment strategies. Therefore, this review focuses on maternal, environmental, and racial factors associated with the development of NEC, with an emphasis on those that may be modifiable to decrease the incidence of the disease.

Necrotizing Enterocolitis: The Role of Hypoxia, Gut Microbiome, and Microbial Metabolites

Necrotizing enterocolitis (NEC) is a life-threatening disease that predominantly affects very low birth weight preterm infants. Development of NEC in preterm infants is accompanied by high mortality. Surgical treatment of NEC can be complicated by short bowel syndrome, intestinal failure, parenteral nutrition-associated liver disease, and neurodevelopmental delay. Issues surrounding pathogenesis, prevention, and treatment of NEC remain unclear. This review summarizes data on prenatal risk factors for NEC, the role of pre-eclampsia, and intrauterine growth retardation in the pathogenesis of NEC. The role of hypoxia in NEC is discussed. Recent data on the role of the intestinal microbiome in the development of NEC, and features of the metabolome that can serve as potential biomarkers, are presented. The Pseudomonadota phylum is known to be associated with NEC in preterm neonates, and the role of other bacteria and their metabolites in NEC pathogenesis is also discussed. The most promising approaches for preventing and treating NEC are summarized.

Risk factors for necrotizing enterocolitis in preterm infants: a Meta analysis

OBJECTIVES

To systematically evaluate the risk factors for necrotizing enterocolitis (NEC) in preterm infants.

METHODS

PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, and Wanfang Data were searched for case-control studies and cohort studies on the risk factors for NEC in preterm infants published up to December 2021. RevMan 5.3 software was used to perform the Meta analysis.

RESULTS

A total of 38 studies were included (28 case-control studies and 10 cohort studies). The Meta analysis showed that maternal gestational diabetes (OR=2.96, P<0.001), intrahepatic cholestasis during pregnancy (OR=2.53, P<0.001), preeclampsia (OR=1.73, P=0.020), history of neonatal asphyxia (OR=2.13, P<0.001), low gestational age (OR=1.23, P=0.010), sepsis (OR=5.32, P<0.001), patent ductus arteriosus (OR=1.57, P=0.001), congenital heart disease (OR=3.78, P<0.001), mechanical ventilation (OR=2.23, P=0.020), history of antibiotic use (OR=1.07, P<0.001), use of vasopressors (OR=2.34, P=0.040), and fasting (OR=1.08, P<0.001) were risk factors for NEC in preterm infants, while cesarean section (OR=0.73, P=0.004), use of pulmonary surfactant (OR=0.43, P=0.008), and breastfeeding (OR=0.24, P=0.020) were protective factors against NEC.

CONCLUSIONS

Maternal gestational diabetes, intrahepatic cholestasis during pregnancy, preeclampsia, low gestational age, fasting, sepsis, patent ductus arteriosus, congenital heart disease, and histories of asphyxia, mechanical ventilation, antibiotic use, and use of vasopressors may increase the risk of NEC in preterm infants, while cesarean section, use of pulmonary surfactant, and breastfeeding may decrease the risk of NEC in preterm infants.

Risk factors for necrotizing enterocolitis in neonates: A meta-analysis

OBJECTIVE

The objective is to identify the risk factors for necrotizing enterocolitis (NEC) in neonates by a meta-analysis, and to provide a reference for the prevention of NEC.

METHODS

The databases, including Chinese Biomedical Literature Datebase, China National Knowledge Infrastructure, Wanfang database, and Weipu Periodical database, PubMed, Web of Science, Embase, Cochrane Library, were searched for studies on the risk factors for NEC in neonates. The meta-analysis was carried out with the aid of Stata software.

RESULTS

A total of 52 studies were included, with 48 case-control studies and 4 cohort studies. There were 166,580 neonates in total, with 33,522 neonates in the case group and 133,058 neonates in the control group. The meta-analysis showed that gestational diabetes (OR = 3.62, 95% CI:1.77-7.41), premature rupture of membranes (OR = 3.81, 95% CI:1.16-12.52), low birth weight (OR = 3.00, 95% CI:2.26-3.97), small for gestational age (OR = 1.85, 95% CI:1.15-2.97), septicemia (OR = 4.34, 95% CI:3.06-6.15), blood transfusion (OR = 3.08, 95% CI:2.16-4.38), congenital heart disease (OR = 2.73, 95% CI:1.10-6.78), respiratory distress syndrome (OR = 2.12, 95% CI:1.24-3.63), premature birth (OR = 5.63, 95% CI:2.91-10.92), pneumonia (OR = 4.07, 95% CI:2.84-5.82) were risk factors for NEC in neonates. Breastfeeding (OR = 0.37, 95% CI:0.23-0.59), take probiotics (OR = 0.30, 95% CI:0.22-0.40), prenatal use of glucocorticoids (OR = 0.39, 95% CI:0.30-0.50), Hyperbilirubinemia (OR = 0.28, 95% CI:0.09-0.86) were protective factors for NEC in neonates.

CONCLUSIONS

Gestational diabetes, premature rupture of membranes, low birth weight, small for gestational age, septicemia, blood transfusion, congenital heart disease, respiratory distress syndrome, premature birth, and pneumonia may increase the risk of NEC in neonates. Breastfeeding, taking probiotics, prenatal use of glucocorticoids, and Hyperbilirubinemia may reduce the risk of NEC in neonates.

Hypertension induced by pregnancy and neonatal outcome: Results from a retrospective cohort study in preterm under 34 weeks

OBJECTIVE

The present study seeks to assess the impact of gestational hypertensive disorders on premature newborns below 34 weeks and to establish the main morbidities and mortality in the neonatal period and at 18 months.

MATERIALS AND METHODS

A retrospective observational study was carried out with 695 premature newborns of gestational age (GA) between 24 and 33 weeks and 6 days, born alive in the Neonatal ICU of Brasília's Mother and Child Hospital (HMIB), in the period from January 1, 2014, to July 31, 2019. In total, 308 infants were born to hypertensive mothers (G1) and 387 to normotensive mothers (G2). Twin pregnancies and diabetic patients with severe malformations were excluded. Outcomes during hospitalization and outcomes of interest were evaluated: respiratory distress syndrome (RDS), brain ultrasonography, diagnosis of bronchopulmonary dysplasia (BPD), diagnosis of necrotizing enterocolitis, retinopathy of prematurity, breastfeeding rate at discharge, survival at discharge and at 18 months of chronological age and relationship between weight and gestational age.

RESULTS

Newborns with hypertensive mothers had significantly lower measurements of birth weight and head circumference. The G1 group had a higher risk small for gestational age (OR 2.4; CI 95% 1.6-3.6; p <0.00), as well as a greater risk of being born with a weight less than 850 g (OR 2.4; 95% CI 1.2-3.5; p <0.00). Newborns of mothers with hypertension presented more necrotizing enterocolitis (OR 2.0; CI 95% 1.1-3.7); however, resuscitation in the delivery room and the need to use surfactant did not differ between groups, nor did the length of stay on mechanical ventilation, or dependence on oxygen at 36 weeks of gestational age. Survival was better in newborns of normotensive mothers, and this was a protective factor against death (OR 0.7; 95% CI 0.5-0.9; p <0.01). In the follow-up clinic, survival at 18 months of chronological age was similar between groups, with rates of 95.3% and 92.1% among hypertensive and normotensive mothers, respectively. Exclusive breastfeeding at discharge was 73.4% in the group of hypertensive women and 77.3% in the group of normotensive mothers. There were no significant differences between groups.

CONCLUSION

Among the analyzed outcomes, arterial hypertension during pregnancy can increase the risk of low weight, small babies for gestational age (SGA), deaths in the neonatal period and enterocolitis, with no differences in weight and survival at 18 months of chronological age. Arterial hypertension presents a high risk of prematurity in the neonatal period, with no difference at 18 months of age.

Potential Prenatal Origins of Necrotizing Enterocolitis

Necrotizing enterocolitis is a serious and yet incompletely understood gastrointestinal disease of infancy that predominately impacts premature neonates. Prevention is a key strategy for the management of necrotizing enterocolitis. Although postnatal risk factors have been the focus of prevention efforts, obstetric complications, including intrauterine inflammation and infection, growth restriction, preeclampsia, and prenatal medications, have been associated with an increased risk of necrotizing enterocolitis. This article reviews the evidence behind the prenatal risk factors for necrotizing enterocolitis, and discusses how these risk factors may elucidate the pathogenesis of necrotizing enterocolitis and provide insight into prevention and treatment.

Association Between Preeclampsia Risk and Fine Air Pollutants and Acidic Gases: A Cohort Analysis in Taiwan

Background: Fine air pollutant particles have been reported to be associated with risk of preeclampsia. The association between air pollutant exposure and preeclampsia risk in heavily air polluted Taiwan warrants investigation.

Methods: We combined data from Taiwan National Health Insurance (NHI) Research Database (NHIRD) and Taiwan Air Quality Monitoring Database. Women aged 16–55 years were followed from January 1, 2000, until appearance of ICD-9 coding of preeclampsia withdrawal from the NHI program, or December 31, 2013. Daily concentration of NOx, NO, NO₂, and CO was calculated by Kriging method. The Cox proportional hazard regression model was used for risk assessment.

Results: For NOx, Relative to Quartile [Q] 1 concentrations, the Q2 (adjusted hazard ratio adjusted = 2.20, 95% CI = 1.50–3.22), Q3 (aHR = 7.28, 95% CI = 4.78–11.0), and Q4 (aHR = 23.7, 95% CI = 13.7–41.1) concentrations were associated with a significantly higher preeclampsia or eclampsia risk. Similarly, for NO, relative to Q1 concentrations, the Q2 (aHR = 1.82, 95% CI = 1.26–2.63), Q3 (aHR = 7.53, 95% CI = 5.12–11.0), and Q4 (aHR = 11.1, 95% CI = 6.72–18.3) concentrations were correlated with significantly higher preeclampsia or eclampsia risk. Furthermore, for NO₂, relative to Q1 concentration, the Q2 (aHR = 1.99, 95% CI = 1.37–2.90), Q3 (aHR = 6.15, 95% CI = 3.95–9.57), and Q4 (aHR = 32.7, 95% CI = 19.7–54.3) concentrations also associated with a significantly higher preeclampsia or eclampsia risk.

Conclusion: Women exposed to higher NO_X, NO, NO₂, and CO concentrations demonstrated higher preeclampsia incidence.

[Clinical features of very preterm small-for-gestational-age infants born due to severe preeclampsia]

OBJECTIVE

To study the clinical features of very preterm small-for-gestational-age infants born by cesarean section due to severe preeclampsia.

METHODS

Forty-two small-for-gestational-age infants who were admitted from August 2017 to July 2018 and were born due to severe preeclampsia were enrolled as the observation group. Forty very preterm infants who were born to healthy mothers since uterine contractions could not be suppressed were enrolled as the control group. Perinatal features, clinical manifestations of infection, complications, and clinical outcomes were analyzed for the two groups.

RESULTS

Within 6 hours and 2-3 days after birth, the observation group had significantly lower white blood cell count (WBC), absolute neutrophil count (ANC), and platelet count (PLT) than the control group (P < 0.05). At 5-7 days after birth, there was no significant difference in WBC between the two groups (P > 0.05), while the observation group still had significantly lower ANC and PLT than the control group (P < 0.05). The observation group had a significantly higher C-reactive protein (CRP) level than the control group at 2-3 days and 5-7 days after birth (P < 0.05). The observation group had a significantly higher proportion of infants with severe infections than the control group (P < 0.05). The observation group had a significantly higher hemoglobin level than the control group within 6 hours after birth (P < 0.05). The observation group had a significantly higher incidence rate of bronchopulmonary dysplasia than the control group (P < 0.05). There was no significant difference between the two groups in the rate of pulmonary hemorrhage, intracranial hemorrhage, neonatal necrotizing enterocolitis, retinopathy of prematurity, and the rate of use of invasive ventilation, and clinical outcomes (P > 0.05).

CONCLUSIONS

Very preterm small-for-gestational-age infants born due to severe preeclampsia have a high incidence rate of infection and severe conditions. Early manifestations include reductions in the infection indicators WBC, ANC, and PLT, and CRP does not increase significantly in the early stage and gradually increases at 2-3 days after birth. Most of these infants require invasive ventilation after birth, with bronchopulmonary dysplasia as the main complication. Clinical changes should be closely observed and inflammatory indicators should be monitored for early identification of infection, timely diagnosis, and timely adjustment of antibiotic treatment, so as to improve the outcome.

Clinical Importance of the Human Umbilical Artery Potassium Channels

Potassium (K⁺) channels are usually predominant in the membranes of vascular smooth muscle cells (SMCs). These channels play an important role in regulating the membrane potential and vessel contractility-a role that depends on the vascular bed. Thus, the activity of K⁺ channels represents one of the main mechanisms regulating the vascular tone in physiological and pathophysiological conditions. Briefly, the activation of K⁺ channels in SMC leads to hyperpolarization and vasorelaxation, while its inhibition induces depolarization and consequent vascular contraction. Currently, there are four different types of K⁺ channels described in SMCs: voltage-dependent K⁺ (K_V) channels, calcium-activated K⁺ (K_Ca) channels, inward rectifier K⁺ (Kir) channels, and 2-pore domain K⁺ (K_2P) channels. Due to the fundamental role of K⁺ channels in excitable cells, these channels are promising therapeutic targets in clinical practice. Therefore, this review discusses the basic properties of the various types of K⁺ channels, including structure, cellular mechanisms that regulate their activity, and new advances in the development of activators and blockers of these channels. The vascular functions of these channels will be discussed with a focus on vascular SMCs of the human umbilical artery. Then, the clinical importance of K⁺ channels in the treatment and prevention of cardiovascular diseases during pregnancy, such as gestational hypertension and preeclampsia, will be explored.

Association of initial empirical antibiotic therapy with increased risk of necrotizing enterocolitis

Whether the prophylactic use of antibiotics increase the risk of necrotizing enterocolitis (NEC) remains controversial. This review aims to investigate initial empirical antibiotic therapy (IEAT) and is associated with the risk of NEC. PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched through March 1, 2020. All studies on the impacts of antibiotic exposure on NEC development were included. Thirteen studies including 7901 participants were selected. Two reviewers independently examined the extracted data and assessed the quality of the included studies. Random-effects model was used to pool the effect estimates. We found that IEAT (≥ 5 days) was associated with an increased risk of NEC in adjusted (Odds risk [OR] 1.51, 95% confidence interval [CI] 1.22-1.87) and unadjusted (OR 2.35, 95% CI 1.54-3.57) analyses. Sensitivity analysis also supported these findings.Conclusion: The evidence suggests an association between IEAT (≥ 5 days) and the risk of NEC. Further studies are needed to address whether the association with IEAT is causal.What is Known:•Necrotizing enterocolitis (NEC) is acute inflammatory necrosis of the intestinal tractin the newborn infant.•Some observational studies have associated initial empirical antibiotics with an increased risk of subsequent NEC.What is New:•Initial empirical antibiotic therapy (IEAT) (≥ 5 days) appear to increase the risk of NEC.

Pregnancy-induced hypertension decreases Kv1.3 potassium channel expression and function in human umbilical vein smooth muscle

Voltage-gated potassium (K_v) channels are the largest superfamily of potassium (K) channels. A variety of K_v channels are expressed in the vascular smooth muscle cells (SMC). Studies have shown that gestational diabetes mellitus (GDM) and pregnancy-induced hypertension (PIH) cause various changes in the human umbilical vein (HUV). Recently, we have shown that 4-AP, a nonspecific K_v1-4 channel inhibitor, significantly decreases vasorelaxation induced by K channel opener pinacidil in vascular SMCs of the HUVs from normal pregnancies, but not in GDM and PIH. The goal of this study was to provide more detailed insight in the K_v channel subtypes involved in pinacidil-induced vasodilation of HUVs, as well as to investigate potential alterations of their function and expression during GDM and PIH. Margatoxin, a specific blocker of K_v1.2 and K_v1.3 channels, significantly antagonized pinacidil-induced vasorelaxation in normal pregnancy, while in HUVs from GDM and PIH that was not the case, indicating damage of K_v1.2 and K_v1.3 channel function. Immunohistochemistry and Western blot revealed similar expression of K_v1.2 channels in all groups. The expression of K_v1.3 subunit was significantly decreased in PIH, while it remained unchanged in GDM compared to normal pregnancy. Phrixotoxin, specific blocker of K_v4.2 and K_v4.3 channels, did not antagonize response to pinacidil in any of the groups. The major novel findings show that margatoxin antagonized pinacidil-induced relaxation in normal pregnancy, but not in GDM and PIH. Decreased expression of K_v1.3 channels in HUV during PIH may be important pathophysiological mechanism contributing to an increased risk of adverse pregnancy outcomes.

Effect of magnesium sulfate on baroreflex during acute hypoxemia in chronically instrumented fetal sheep

AIM

To investigate the effects of magnesium sulfate on fetal baroreflex in normoxemia or acute fetal hypoxemia.

METHODS

Fetal baroreflex response was elicited using phenylephrine (30 μg) in saline and magnesium sulfate in 8 chronically treated and instrumented fetal sheep. Hypoxemia was induced using nitrogen gas inflow for 30 min. Baroreflex, calculated as the ratio of the fetal heart rate change to the mean arterial pressure, was monitored after magnesium sulfate administration and in rapid and nonrapid eye movement (NREM) sleep states. Baroreflex was assessed in response to hypoxemia in control groups in both the rapid and NREM sleep states.

RESULTS

Baroreflex was not significantly affected by saline, magnesium sulfate and rapid or NREM sleep states in normoxemic sheep. Hypoxemia increased the baroreflex in the saline-treated group (hypoxemic vs normoxemic rapid eye movement sleep: 4.37 ± 2.48 vs 2.72 ± 0.83; P < 0.05; hypoxemic vs normoxemic NREM sleep: 4.30 ± 1.47 vs 3.15 ± 0.83; P < 0.001). Magnesium sulfate decreased the baroreflex in the hypoxemic fetuses (magnesium sulfate hypoxemic vs. control normoxemic fetuses: 1.42 ± 0.92 vs 3.15 ± 0.83, P < 0.05).

CONCLUSION

The hypoxemic fetal sheep, from the ewes that were receiving magnesium sulfate, showed a significantly reduced in the baroreflex response. In clinical practice, baroreflex-related decelerations in hypoxemic fetuses of mothers receiving magnesium sulfate should be carefully interpreted.

Original low birth weight deteriorates the hindgut epithelial barrier function in pigs at the growing stage

The deteriorative effect of low birth weight (LBW) on the mucosal permeability of the small intestine in piglets has been widely confirmed. However, whether the hindgut epithelial barrier function in LBW pigs is deteriorated during the growing stage is still unclear. Our study investigated differences in the hindgut epithelial barrier function between LBW and normal birth weight pigs during the growing stage (d 90). Our data demonstrated that the hindgut epithelium of LBW pigs has a high histopathological score, accompanied by decreased antioxidant capacity and increased apoptosis rate, as well as elevated expression and activity of caspase-3. In addition, the number of intestinal goblet cells and gene expression of mucin 2 were significantly down-regulated in LBW pigs. The expression of tight junction proteins (ZO-1 and occludin) was markedly inhibited by the LBW. The mRNA abundance of inflammatory cytokines such as TNF-α, IL-1β, and IL-8 was significantly increased in the hindgut mucosa of LBW pigs. Furthermore, our data revealed that LBW altered the intestinal microbial community in the hindgut mucosa of pigs. Collectively, these finding add to our understanding of the mechanisms responsible for hindgut epithelial barrier dysfunction in LBW pigs during the growing stage and facilitate the development of nutritional intervention strategies.-Tao, S., Bai, Y., Li, T., Li, N., Wang, J. Original low birth weight deteriorates the hindgut epithelial barrier function in pigs at the growing stage.