Biochemical profile of amniotic fluid for the assessment of fetal and renal development

Canine and feline foetal fluids: Volume, hormonal and biochemical characterization during pregnancy

BACKGROUND AND OBJECTIVES

This study aimed to evaluate the volume, the concentration of steroid hormones, and biochemical composition of the foetal fluids at different gestational ages in dogs and cats.

METHODS

Following the ovariohysterectomy, the allantoic and amniotic fluid samples were collected from pregnant bitches and queens and were assigned to different groups according to their gestational age.

RESULTS

The canine and feline allantoic fluid volume increased during pregnancy, reached its maximum values on days 40-49 and then decreased. The canine and feline amniotic fluid volume increased steadily by the last days of pregnancy. In spite of significant changes of sex hormones in the foetal fluids, their concentration and ratios were not significantly different between male and female fetuses. The canine amniotic cortisol concentration increased until days 40-49 and decreased significantly afterwards. The maximum cortisol concentrations in the feline allantoic and amniotic fluids were observed on days 50-60 and 40-49, respectively. During the canine pregnancy, the concentrations of calcium, phosphorus, chloride, sodium, triglyceride, cholesterol, total protein, albumin and the activities of aminotransferase (AST), alkaline phosphatase (ALP), amylase and gamma-glutamyl transferase (GGT) in the amniotic fluid were higher than the allantoic fluid. The magnesium, potassium, lactate dehydrogenase (LDH) activity, creatine and lipase were higher in the allantoic fluid. In the feline allantoic fluid, potassium, magnesium, phosphorus, creatinine, albumin and glucose concentrations and the activities of creatine kinase (CK), GGT, LDH and lipase were higher. The ALP, AST activities, sodium and calcium concentrations were higher in the amniotic fluid (p < 0.05).

CONCLUSION

Volume of foetal fluids was determined in dogs and cats. Concentration of sex hormones did not different between male and female fetuses.

Is salivary uric acid, a putative biomarker of pre-eclampsia, of maternal, placental, or fetal origin?

OBJECTIVES

Increased salivary uric acid (sUA) represents a potential biomarker predictive of pre-eclampsia (PE), but its origin is unclear. The study explores whether sUA levels reflect maternal or feto-placental physiological stress and whether sUA levels in these cases correlate with amniotic fluid (fetal origin), maternal blood (maternal origin), or cord blood (fetal vs placental origin).

STUDY DESIGN

Pregnant women (n = 39) undergoing amniotomy or caesarean section after 34 gestational weeks were designated into three groups of either maternal, feto-placental, or no signs of physiological stress: women (n = 15) in the established first phase of active labour and without any signs of fetal growth restriction (FGR) or PE were assigned to the maternal stress group, women (n = 6) with an ultrasound-based diagnosis of FGR, with or without PE, were assigned to the feto-placental stress group, and women (n = 18) not yet in active labour and without any signs of FGR or PE, were assigned to the control group. Uric acid levels in corresponding samples of amniotic fluid, saliva, maternal blood, and cord blood were compared between groups and between body compartments within each group.

RESULTS

The feto-placental stress group showed increased UA levels in saliva (median, interquartile range [IQR]: 0.47 [0.38] mmol/L, P = 0.023) and maternal blood (0.42 [0.13] mmol/L, P = 0.032), but no differences in amniotic fluid or cord blood compared with the other groups. Within the control and maternal stress group, sUA levels were lower compared with maternal blood (0.20 [0.08] vs 0.25 [0.08] mmol/L, Pcontrol = 0.018; 0.20 [0.06] vs 0.26 [0.08] mmol/L, Pmaternal = 0.001) and highest in amniotic fluid (control group (0.49 [0.18] mmol/L): Pmaternal,blood = 0.001, Pumbilical,artery = <0.001, Pumbilical,vein = <0.001, Psaliva = <0.001) (maternal stress group (0.56 [0.23] mmol/L): Pmaternal,blood = 0.021, Pumbilical,artery = 0.006, Pumbilical,vein = 0.004, Psaliva = 0.003). Levels did not differ between compartments in the feto-placental stress group.

CONCLUSIONS

Salivary and maternal blood UA levels were increased in the feto-placental stress group with salivary levels increasing more than blood levels compared with the maternal stress and control groups, whilst UA in amniotic fluid were not different between the groups, suggesting a placental origin and potential use of sUA as a biomarker of placental dysfunction, including FGR and severe PE.

Amniotic fluid metabolic fingerprinting contributes to shaping the unfavourable intrauterine environment in monochorionic diamniotic twins

BACKGROUND & AIMS

Amniotic fluid (AF) is the primary intrauterine environment for fetal growth throughout gestation. Selective fetal growth restriction (sFGR) is an adverse complication characterized by unequal growth in twins with nearly identical genetic makeup. However, the influence of AF-mediated intrauterine environment on the development and progression of sFGR remains unexplored.

METHODS

High-throughput targeted metabolomics analysis (G350) was performed on AF samples collected from sFGR (n = 18) and MCDA twins with birth weight concordance (MCDA-C, n = 20) cases. Weighted correlation network analysis (WGCNA) was used to identify clinical features that may influence the metabolite composition in AF. Subsequently, partial least-squares discriminant analysis (PLS-DA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to compare the different types of sFGR and MCDA-C twins. Receiver operating characteristic (ROC) and multivariate ROC curves were utilized to explore potential AF markers in twins with sFGR.

RESULTS

In our study, 182 metabolites were quantified in 76 AF samples. WGCNA indicated that the metabolite composition in late AF may not be influenced by gestational age. PLSDA demonstrated distinct variations between the metabolite profiles of AF in the sFGR and MCDA-C twins, with a significant emphasis on amino acids as the primary differential metabolite. The dissimilarities observed in sFGR twins were predominantly attributed to lipid metabolism-related metabolites. In particular, the KEGG enrichment metabolic pathway analysis revealed significant associations of both types of sFGR twins with central carbon metabolism in cancer. The multivariate ROC curves indicated that the combination of carnosine, sarcosine, l-alanine, beta-alanine, and alpha-n-phenylacetylglutamine significantly improved the AUC to 0.928. Notably, the ROC curves highlighted creatine (AUC:0.934) may be a potential biomarker for severe sFGR.

CONCLUSION

The data presented in this study offer a comprehensive metabolic map of the AF in cases of sFGR, shedding light on potential biomarkers associated with fetal growth and development in MCDA twins.

Quantification of Fetal Renal Function Using Fetal Urine Production Rate and Its Reflection on the Amniotic and Fetal Creatinine Levels During Pregnancy

Adequate prediction of fetal exposure of drugs excreted by the kidney requires the incorporation of time-varying renal function parameters into a pharmacokinetic model. Published data on measurements of fetal urinary production rate (FUPR) and creatinine at various gestational ages were collected and integrated for prediction of the fetal glomerular filtration rate (GFR). The predicted GFR values were then compared to neonatal values recorded at birth. Collected data for FUPR across different gestational ages using both 3D (N = 517) and 2D (N = 845) ultrasound methods showed that 2D techniques yield significantly lower estimates of FUPR than 3D (p < 0.0001). A power law function was shown to best capture the change in FUPR with fetal age (FA) for both 2D ( F U P R 2 D ( m L min ) = 0 . 000169     FA 2 . 19 ); and 3D ( F U P R 3 D   ( m L min ) =   3 . 21 × 1 0 - 7   FA 4 . 21 ) data. The predicted FUPR based on the observed 3D data was shown to be strongly linearly related (R ² = 0.95) to measured values of amniotic creatinine concentration (N = 664). The FUPR_3D data together with creatinine levels in the fetal urine and serum resulted in median predicted fetal GFR values of 0.47, 1.2, 2.5, and 4.9 ml/min at 23, 28, 33, and 38 weeks of fetal age (50% CV), respectively. These values are in good agreement with neonatal values observed immediately at birth. The derived FUPR and creatinine functions can be utilized to assess fetal renal maturation and predict fetal renal clearance.

Changes in the morphometry of the uterus, ovary, and foetus, and biochemistry of allantoic and amniotic membrane fluids of Yankasa ewes across the gestation period

This study evaluated the uterine and fetal morphometric changes and fetal membrane fluids biochemistry across the gestation of Yankasa sheep. The amniotic and allantoic fluids are actively involved in the constant physiologic exchange between the fetus and maternal circulation. Hence, the knowledge regarding changes in the composition of fetal membrane fluids is important for understanding fetal metabolism, and the diagnosis of pathophysiological conditions during gestation. Gravid uteri from 37 ewes and their corresponding ovaries were sampled. The number and size of the placentomes in the second and third terms of gestation were significantly higher relative to the first term. The total protein, albumin, glucose, urea, creatinine, and calcium levels as well as alkaline phosphatase (ALP) and aspartate aminotransferase (AST) activities were higher in the allantoic fluid. In the allantoic fluid, the levels of total protein, globulin, and the activity levels of ALT and AST increased progressively with the advancement of gestation; contrarily, the levels of calcium, chloride, and the activity level of ALT decreased. For the amniotic fluid, the levels of total protein, globulin, urea, calcium, and the enzyme activities in the second and third terms did not differ but were higher than the level in the first term of gestation. In addition, the most significant increases in creatinine level and white blood cell count were observed in the third term of gestation. Therefore, notable differences in the levels of ALT, AST, total proteins, glucose, urea, creatinine, and WBC counts were observed in the two fetal membrane fluids.

The Risk of Necrotizing Enterocolitis following the Administration of Hyperosmolar Enteral Medications to Extremely Preterm Infants

INTRODUCTION

Necrotizing enterocolitis (NEC) is a disease predominantly affecting preterm infants. The administration of hyperosmolar solutions could lead to the development of NEC. The objective of this study was to measure the osmolality of enteral medications used in clinical practice and to assess the risk of NEC following exposure to hyperosmolar medications.

METHODS

A retrospective cohort study in extremely preterm infants (gestational age <28 weeks) born between 2010 and 2016 at a tertiary neonatal intensive care unit in Sweden. 465 infants were identified via the Swedish Neonatal Quality register. Data relating to enteral administrations received during a two-week period were collected from the medical records. The osmolalities of medications were measured using an osmometer. Logistic regression was used to calculate the odds ratio of developing NEC.

RESULTS

A total of 253 patients met the inclusion criteria. The osmolalities of 5 commonly used medications significantly exceeded the recommended limit of 450 mOsm/kg set by the American Academy of Paediatrics (AAP). Most patients (94%) received at least one hyperosmolar medication. No significant risk of developing NEC could be found.

CONCLUSION

The medications used in clinical practice can significantly exceed the limit set by the AAP. This study does not indicate an increased risk of developing NEC in extremely preterm infants following exposure to hyperosmolar medications. Further studies in larger cohorts are needed to determine the specific cut-off level of osmolality in relation to the pathogenesis of NEC.

Is chlorine and sodium levels in the amniotic fluid a new marker for fetal lung maturation and RDS severity?

BACKGROUND

Amniotic fluid (AF) is a dynamic liquid whose contents vary according to the needs of the fetus. Levels of the amniotic components have been used in numerous studies as potential biomarkers to screen pregnancy-related abnormalities. As a reflection of Na⁺ and Cl^- levels of fetal lung fluid, amniotic fluid's Na⁺ and Cl^- levels can be used as an indicator of lung maturation in the newborn period. This study aimed to investigate whether Na⁺ and Cl^- levels in the amniotic fluid would be a new marker to determine the severity of respiratory distress and pulmonary maturation in the newborn.

METHODS

This prospective cohort study was conducted at Hacettepe University Neonatal Intensive Care Unit. One hundred twenty single infants who were delivered with the cesarean section between January 2015 and March 2016 were included. Na⁺ and Cl^- levels were measured from AF.

RESULTS

There were 46 of 120 infants (33.3%) in Group-1 and 74 infants (66.7%) in Group-2. Na + and Cl^- levels of the AF of Group-1 were higher than Group 2 and this was statistically significant (p < .001/p: .01, respectively). Na⁺ and Cl^- levels of the AF were significantly higher in infants who needed surfactant (p < .001/p: .001, respectively).

CONCLUSION

Our results showed that Na⁺ and Cl^- levels of the AF can be used as an indicator of infant lung maturation.

Metabolomic Profile of Allantoic and Amniotic Fluid in Late-term Gestational Mares Characterized by 1H-nuclear Magnetic Resonance Spectroscopy

The amniotic and allantoic fluid compartments in the mare serve essential roles throughout pregnancy and parturition. Although the global metabolomic profile of amniotic fluid in women has been extensively characterized, current data for equine fetal fluids are limited. Therefore, the goal of this study was to characterize the global metabolomic profile of equine allantoic and amniotic fluid through nuclear magnetic resonance spectroscopy. Fetal fluids were collected between 270 and 295 days of gestation from 12 pregnancies through ultrasound-guided transabdominal puncture. A total of 24 samples (n = 10 allantoic fluid; n = 9 amniotic fluid; n = 5 admixed fluid) were analyzed by one-dimensional proton (¹H) and two-dimensional (¹H-¹³ C) nuclear magnetic resonance spectroscopy. Metabolites were integrated and compared between fluid types using a Kruskal-Wallis test at P < .05 significance. A total of 28 distinct metabolites were found in allantoic and admixed fluid, whereas 23 metabolites were identified in amniotic fluid. Allantoic fluid contained significant elevations (P < .05) in the metabolites betaine, creatine, creatinine, citrate, histidine, nitrophenol, tryptophan, π-methylhistidine, and unknown metabolite #1 compared with amniotic fluid, whereas amniotic fluid contained statistically increased concentrations of the metabolite lactate compared with allantoic fluid (P = .003).

Vaginal Fluid Urea and Creatinine as Indicators of Premature Rupture of Membranes: a Systematic Review

The purpose of the present study was to determine the diagnostic accuracy of vaginal urea and creatinine levels in the detection of premature rupture of membrane (PROM). The Cochrane (central), EMBASE, PubMed, Scopus, and Web of Science were searched for studies published from the inception of the databases up to January 2020. We included published observational full-text articles. The mean differences (MD) and 95% confidence intervals (95% CI) were calculated. The significance level was set as 0.05. Eleven studies (n = 1324) were considered for meta-analysis. Using the bivariate model, the summary estimate of sensitivity and specificity for urea was 0.96 (95% CI: 0.86, 0.98) and 0.93 (95% CI: 0.83, 0.97), respectively. The summary estimate of sensitivity and specificity for creatinine was 0.98 (95% CI: 0.92, 0.99) and 0.97 (95% CI: 0.89, 0.99), respectively. The overall mean of urea and creatinine in the case group was significantly higher than that in the control group (MD = 12.63, 95%, CI [12.01, 13.25]) and (MD = 0.31, 95%, CI [0.29, 0.32]), respectively. The results of this systematic review showed that the mean of urea and creatinine in the case group was significantly higher than that in the control group and the sensitivity and specificity of creatinine is higher than urea in the diagnosis of PROM.

Inorganic Phosphate in the Pathogenesis of Pregnancy-Related Complications

Inorganic phosphate (P_i) is an essential nutrient that fulfills critical roles in human health. It enables skeletal ossification, supports cellular structure and organelle function, and serves key biochemical roles in energetics and molecular signaling. P_i homeostasis is modulated through diet, intestinal uptake, renal reabsorption, and mobilization of stores in bone and extracellular compartments. Disrupted P_i homeostasis is associated with phosphate wasting, mineral and bone disorders, and vascular calcification. Mechanisms of Pi homeostasis in pregnancy remain incompletely understood. The study presented herein examined biological fluid Pi characteristics over the course of gestation. Correlations with gestation age, pregnancy number, preterm birth, preeclampsia, diabetes mellitus, and placental calcification were evaluated during the last trimester. The results support that maternal urinary P_i levels increased during the third trimester of pregnancy. Reduced levels were observed with previous pregnancy. Amniotic fluid P_i levels decreased with gestation while low second trimester levels associated with preterm birth. No significant difference in urinary P_i levels was observed between preeclampsia and controls (8.50 ± 2.74 vs. 11.52 ± 2.90 mmol/L). Moreover, increased maternal urinary P_i was associated with preexisting diabetes mellitus in preeclampsia. Potential confounding factors in this study are maternal age at delivery and body mass index (BMI)—information which we do not have access to for this cohort. In conclusion, P_i levels provide clinical information regarding the pathogenesis of pregnancy-related complications, supporting that phosphate should be examined more closely and in larger populations.

Gestational Age-Dependent Fetal Fluid Dynamics in the Ovine Developmental Model: Establishment of Surrogate Markers for the Differentiation of Stem Cell Origin

The ovine developmental model represents the standard in vivo model for studies involving maternofetal physiology, amniotic fluid (AF) research, and fetal cell therapy prior to human clinical use. Although being close to the human fetal anatomy, 2 separate extraembryonic fluid compartments remain during gestation, known as the amnion and the allantois. A clear distinction between AF versus allantoic fluid (AL) is therefore indispensable for correct scientific conclusions with regard to human translation. In the presented study, the biochemical composition of AF and AL was evaluated in ovine gravid uteri postmortem (n = 31) over the entire gestation. Four parameters, consisting of Na+, Cl-, Mg2+, and total protein, have been found to allow for specific discrimination of the 2 fetal fluids at all gestational phases and therefore as potential surrogate parameters for gestational age. In addition, volumetric changes of the developing fetus and the 2 fetal fluid cavities were analyzed by contrast-enhanced computed tomography (n = 12). AF showed a significant, linear volumetric increase over gestation, whereas AL volume maintained relatively static independent of gestational age. These results serve as a basis for future studies by providing surrogate markers enabling a reliable distinction of isolated fetal fluids and contained cells in the ovine developmental model over the entire gestation.

The protective arm of the renin-angiotensin system may counteract the intense inflammatory process in fetuses with posterior urethral valves

OBJECTIVE

Posterior urethral valve is the most common lower urinary tract obstruction in male children. A high percentage of patients with posterior urethral valve evolve to end-stage renal disease. Previous studies showed that cytokines, chemokines, and components of the renin-angiotensin system contribute to the renal damage in obstructive uropathies. The authors recently found that urine samples from fetuses with posterior urethral valve have increased levels of inflammatory molecules. The aim of this study was to measure renin-angiotensin system molecules and to investigate their correlation with previously detected inflammatory markers in the same urine samples of fetuses with posterior urethral valve.

METHODS

Urine samples from 24 fetuses with posterior urethral valve were collected and compared to those from 22 healthy male newborns at the same gestational age (controls). Renin-angiotensin system components levels were measured by enzyme-linked immunosorbent assay.

RESULTS

Fetuses with posterior urethral valve presented increased urinary levels of angiotensin (Ang) I, Ang-(1-7) and angiotensin-converting enzyme 2 in comparison with controls. ACE levels were significantly reduced and Ang II levels were similar in fetuses with posterior urethral valve in comparison with controls.

CONCLUSIONS

Increased urinary levels of angiotensin-converting enzyme 2 and of Ang-(1-7) in fetuses with posterior urethral valve could represent a regulatory response to the intense inflammatory process triggered by posterior urethral valve.

Osmolality of a fortified human preterm milk: The effect of fortifier dosage, gestational age, lactation stage, and hospital practices

OBJECTIVE

The purpose of this study was to evaluate the dose-dependent effect of human milk fortifier (HMF) on the osmolality of various preterm human milks (PHMs) at different gestational and lactation stages, and with different storage and treatment conditions that are routinely used in neonatal intensive care units (NICUs).

STUDY DESIGN

Twenty-four mothers who had given birth to their baby before 28 or between 29 and 31 weeks of pregnancy participated in the study after 1-2 weeks or 3-4 weeks breastfeeding after delivery. The study was a prospective, multicenter, comparative, and noninterventional study. Osmolality of fresh or pasteurized human milk stored at 4°C was measured (cryoscopy) at baseline, and 24hours after adding Suppletine^® Human Milk fortifier (SHMF) at 3%, 4%, 4.5%, and 5% (w/v).

RESULTS

PHM without supplementation had an osmolality (mean±SD) of 301±8 mOsm/kgH₂O (n=40; 95% CI: [298; 303]). Adding 3-5% SHMF induced a linear increase of osmolality (P<0.001; r²=0.975). With 4% SHMF, the osmolality measure was 443±13mOsm/kg H₂O (95% CI: [439-447]). Neither a 24-hour storage at 4°C nor pasteurization induced a modification of osmolality compared to the fresh samples.

CONCLUSION

Whatever the origin and quality of milk as well as hospital practices, adding up to 4% (w/v) SHMF to PHM increases its nutritional quality and osmolality without exceeding 450mOsm/kgH₂O, which is generally recognized as safe.

The Effect of Additives for Reflux or Dysphagia Management on Osmolality in Ready-to-Feed Preterm Formula: Practice Implications

BACKGROUND

A common osmolality threshold for feedings is to stay <450 mOsm/kg for normal infants. Preterm formulas are frequently modified to improve growth, modify nutrition, and manage gastroesophageal reflux (GER) or dysphagia. Relationships between osmolality and additives to ready-to-feed preterm formulas are unclear. Our aims were to evaluate and compare the effects of caloric density, thickening agent recipes, and supplements to ready-to-feed preterm formula on osmolality.

METHODS

A freezing point osmometer was used to measure the osmolality of 47 preterm infant formula combinations with varying caloric densities (ready-to-feed 22 and 30 cal/oz), thickening agents (rice vs oatmeal cereal), thickener amounts (0.0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 tsp/oz), and combinations of supplements (saline, iron, vitamin D, or multivitamin). Ten samples per combination were tested using a 10-μL pipette. Comparisons were made using analysis of variance and t-tests for group and pair-wise comparisons, respectively.

RESULTS

A total of 470 osmolality samples were analyzed: (1) raters had high agreement (r = 0.98; P < .001); (2) for every 0.5 tsp/oz of thickener, the osmolality increases by 30 mOsm/kg (P < .001); (3) osmolality was higher with the oatmeal (vs rice) thickening agent (P < .001); and (4) vitamin and electrolyte supplement combinations increase osmolality.

CONCLUSIONS

Alteration of ready-to-feed preterm formulas may significantly increase osmolality and have unintended consequences. Caution and monitoring should be exercised with modifying ready-to-feed preterm formulas for regurgitation, rumination, GER, dysphagia, feeding intolerance, or emesis. This study supports the concept of achieving volume tolerance before further manipulation of additives.

Biochemical composition of fetal fluids in at term, normal developed, healthy, viable dogs and preliminary data from pathologic littermates

A proper canine neonatal assistance, required to reduce the high perinatal loss rate, imply a full knowledge about the fetal-to-neonatal physiology. Because fetal fluids play an important role throughout mammals pregnancy, influencing fetal growth and development, fetal well being, and contributing to guarantee the most suitable environment for the fetus, the knowledge about fetal fluids biochemical composition is of major importance. At first, the biochemical composition of fetal fluids collected by normal developed, healthy and viable newborns, is necessary to depict the normal features, and represent the first step for the further detection of abnormalities associated to fetal/neonatal distress and useful for the early identification of newborns needing special attention, immediately after birth. The present study was aimed to define the biochemical composition of amniotic and allantoic fluids collected from fetus delivered by caesarean section at term of pregnancy. To reduce the possible confounding effect of maternal labor or troubles at parturition, fetal fluids were collected only from puppies born by elective caesaeran section, at term of normal pregnancies. Fetal fluids from 76 puppies, 70 normal and six pathologic newborns, born by elective caesarean section were collected and analyzed for alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin, lactate dehydrogenase (LDH), creatine-kinase (CK), alkaline phosphatase (ALP), creatinine, urea, amylase, lipase, gamma-glutamyl transferase (γ-GT), triglycerides, cholesterol, total proteins, albumin, globulins, glucose, magnesium, potassium, chloride, sodium, calcium, phosphorus and osmolarity. No significant differences were found between biochemical composition of amniotic or allantoic fluid in normal and pathologic newborns, maybe due to the small number of the pathologic puppies. Although some correlations between the two fluids were found (albumin, phosphorus, glucose and triglycerides), the results showed significant differences between the amniotic and allantoic biochemical composition (for all the parameters, except of alanine aminotransferase, triglycerides, cholesterol, albumin, amylase and glucose), suggesting that diverse sources could concur to the final composition of each fluid. A wide variability within and among litters was found for both amniotic and allantoic biochemical composition, and for some parameters an influence of breed body size (amniotic amylase, cholesterol, and allantoic calcium and glucose), maternal parity (amniotic and allantoic CK, glucose, LDH, chloride) and newborn gender (allantoic phosphorus) was found. Further investigations are needed for addressing the origin of each fetal fluid biochemical composition in the dog and also to indeep possible differences in fetal fluids biochemical composition between normal and pathologic puppies, providing potential markers for the quick identification of newborns that need special surveillance and cares immediately after birth.

Vaginal discharge concentrations of β-human chorionic gonadotropin, creatinine, and urea for the diagnosis of premature rupture of membranes

OBJECTIVE

To determine the diagnostic value of vaginal discharge concentrations of β human chorionic gonadotropin (β-hCG), creatinine, and urea to identify premature rupture of membranes (PROM).

METHODS

An observational cross-sectional study was conducted between 12 June, 2014, and 11 June, 2015, among 120 women who were admitted to an Iranian hospital at 28-41 weeks of pregnancy. Women with positive pooling and nitrazine test results were assigned to the PROM group (n=60), whereas those with negative test results were assigned to the control group (n=60). Samples of vaginal discharge were obtained.

RESULTS

Mean concentrations of β-hCG, urea, and creatinine were all higher in the PROM group than in the control group (all P=0.001). The diagnostic accuracies as defined by area under the curve for creatinine, urea, and β-hCG were 0.891, 0.895, and 0.908, respectively. The corresponding optimal cutoff values were 20.33 μmol/L, 0.94 mmol/L, and 39.5 IU/L, respectively.

CONCLUSION

The vaginal discharge concentrations of all three markers exhibited favorable predictive value for the diagnosis of PROM; however, β-hCG showed greater diagnostic accuracy than either urea or creatinine.

Posterior urethral valve in fetuses: evidence for the role of inflammatory molecules

BACKGROUND

The aim of this cross-sectional study was to investigate inflammatory biomarkers in urine samples of 24 fetuses with posterior urethral valve (PUV) collected at 22 ± 4 weeks of gestation and to compare the findings with measurements in urine samples of 22 male healthy preterm neonates at 23 ± 4 weeks (control group).

METHODS

Inflammatory biomarkers in urine were measured using a cytometric bead array [interleukin (IL)-2, IL-4, IL-6, IL-10, interferon (IFN)-γ, soluable tumor necrosis factor receptor (TNFR) 1, sTNFR2, monocyte chemoattractant protein-1/chemokine ligand 2 (MCP-1/CCL2), eotaxin/CCL11 and interferon gamma-induced protein/10/C-X-C motif chemokine 10 (IP-10/CXCL10)] and ELISA assays [TNF, IL-8/CXCL8 and transforming growth factor-beta (TGF-β)]. The Mann-Whitney test was used to compare medians. Markers of glomerular (creatinine) and tubular [beta 2 (β₂)-microglobulin, uromodulin, osmolality] functions were correlated with inflammatory biomarkers (Spearman test).

RESULTS

An intense inflammatory profile was identified, with significantly increased concentrations of urinary IL-2, IL-4, IL-6, TNF, sTNFRI, sTNFRII, IFN-γ, MCP-1/CCL2, eotaxin/CCL11 and IL-8/CXCL8 in the PUV group compared to the controls. The same was observed for the anti-inflammatory cytokine IL-10 and for the fibrogenic mediator TGF-β. In the correlation analysis, β₂-microglobulin positively correlated with the presence of MCP-1/CCL2, sTNFRI and eotaxin/CCL11 and negatively correlated with the presence of creatinine.

CONCLUSIONS

This study shows that inflammatory molecules are already increased in fetuses with PUV at the mean gestational age of 22 weeks, suggesting a physiopathological role for inflammation just after the embryological formation of the urethral membrane.

Medications That Increase Osmolality and Compromise the Safety of Enteral Feeding in Preterm Infants

BACKGROUND

Medications added to preterm milk feeds have the potential to raise osmolality, causing feed intolerance and necrotizing enterocolitis.

OBJECTIVE

The aim of this study was to evaluate changes in the osmolality of milk feeds and water with 14 medications and the diluent amounts required to keep the osmolality below the safety threshold of ≤450 mOsm/kg. Changes in the osmolality of milk with medications while on continuous infusion over 2 and 4 h were determined.

METHODS

This study was designed to measure the osmolality of 14 commonly used medications in preterm infants both neat and when supplemented with expressed breast milk (EBM), EBM with fortifier (EBMF), preterm formula (PTF), and water. Dose-effect curves were plotted, and the volume of each diluent was calculated to keep the osmolality ≤450 mOsm/kg. Time-effect curves were plotted at 2 and 4 h for each medication for both EBM and EBMF.

RESULTS

Neat osmolality of all except 5 medications were above 2,000 mOsm/kg. The osmolality rose with decreasing proportions of diluents used, depicting an indirect curvilinear relationship between the increasing dilution and osmolality for all except 2 medications. As a diluent, EBM was required in lower dilutions than EBMF. Dilutions needed for additives with PTF were very similar to those of EBM. The change in osmolality over time with additives was statistically significant for EBMF.

CONCLUSIONS

EBM and PTF were found to be safer diluents than EBMF for enteral additives. The practice of keeping milk feeds with medications for continuous feeding is safe for a period of 4 h in EBM.

Vaginal Lactoferrin Modulates PGE2, MMP-9, MMP-2, and TIMP-1 Amniotic Fluid Concentrations

Inflammation plays an important role in pregnancy, and cytokine and matrix metalloproteases (MMPs) imbalance has been associated with premature rupture of membranes and increased risk of preterm delivery. Previous studies have demonstrated that lactoferrin (LF), an iron-binding protein with anti-inflammatory properties, is able to decrease amniotic fluid (AF) levels of IL-6. Therefore, we aimed to evaluate the effect of vaginal LF administration on amniotic fluid PGE₂ level and MMP-TIMP system in women undergoing genetic amniocentesis. One hundred and eleven women were randomly divided into controls (n = 57) or treated with LF 4 hours before amniocentesis (n = 54). Amniotic fluid PGE₂, active MMP-9 and MMP-2, and TIMP-1 and TIMP-2 concentrations were determined by commercially available assays and the values were normalized by AF creatinine concentration. PGE₂, active MMP-9, and its inhibitor TIMP-1 were lower in LF-treated group than in controls (p < 0.01, p < 0.005, and p < 0.001, resp.). Conversely, active MMP-2 (p < 0.0001) and MMP-2/TIMP-2 molar ratio (p < 0.001) were increased, whilst TIMP-2 was unchanged. Our data suggest that LF administration is able to modulate the inflammatory response following amniocentesis, which may counteract cytokine and prostanoid imbalance that leads to abortion. This trial is registered with Clinical Trial number NCT02695563.

Metabolomics of Human Amniotic Fluid and Maternal Plasma during Normal Pregnancy

Metabolic profiles of amniotic fluid and maternal blood are sources of valuable information about fetus development and can be potentially useful in diagnosis of pregnancy disorders. In this study, we applied 1H NMR-based metabolic profiling to track metabolic changes occurring in amniotic fluid (AF) and plasma (PL) of healthy mothers over the course of pregnancy. AF and PL samples were collected in the 2nd (T2) and 3rd (T3) trimester, prolonged pregnancy (PP) until time of delivery (TD). A multivariate data analysis of both biofluids reviled a metabolic switch-like transition between 2nd and 3rd trimester, which was followed by metabolic stabilization throughout the rest of pregnancy probably reflecting the stabilization of fetal maturation and development. The differences were further tested using univariate statistics at α = 0.001. In plasma the progression from T2 to T3 was related to increasing levels of glycerol, choline and ketone bodies (3-hydroxybutyrate and acetoacetate) while pyruvate concentration was significantly decreased. In amniotic fluid, T2 to T3 transition was associated with decreasing levels of glucose, carnitine, amino acids (valine, leucine, isoleucine, alanine, methionine, tyrosine, and phenylalanine) and increasing levels of creatinine, succinate, pyruvate, choline, N,N-dimethylglycine and urocanate. Lactate to pyruvate ratio was decreased in AF and conversely increased in PL. The results of our study, show that metabolomics profiling can be used to better understand physiological changes of the complex interdependencies of the mother, the placenta and the fetus during pregnancy. In the future, these results might be a useful reference point for analysis of complicated pregnancies.

Second trimester amniotic fluid glucose, uric acid, phosphate, potassium, and sodium concentrations in relation to maternal pre-pregnancy BMI and birth weight centiles

OBJECTIVE

To study the evolution profile of amniotic fluid (AF) glucose, uric acid, phosphate, potassium, and sodium, in the second trimester of pregnancy, and explore the possible relations between the concentration of these components and maternal, as well as neonatal characteristics.

METHODS

AF of 52 pregnant women was analyzed using an automatic multichannel analyzer. Maternal age, pre-pregnancy Body Mass Index (BMI), inter-pregnancy intervals, and smoking status were derived from questionnaires. Information on pregnancy and delivery was collected from medical records.

RESULTS

Uric acid increased (r = 0.423, p < 0.01), while phosphate and glucose concentrations decreased during the period of 16-26th week of pregnancy (r = -0.590, p < 0.001 and r = -0.314, p < 0.05, respectively). Maternal pre-pregnancy BMI was significantly correlated with AF uric acid concentration (r = 0.460, p < 0.01) and marginally with AF glucose (r = 0.274, p = 0.052) and sodium (r = 0.254, p = 0.070) levels. Multiple linear regression indicated that mid-trimester AF uric acid and phosphate levels were significantly related to birth weight centiles (R(2)( )= 0.345, p < 0.05).

CONCLUSIONS

Our results suggest that: (a) AF phosphate levels reflect gestational age to a satisfactory extent, (b) maternal pre-pregnancy BMI is significantly correlated with AF uric acid concentration, and (c) in appropriate for gestational age infants, AF phosphate and uric acid levels may serve as potential biomarkers of birth weight centiles. Further studies on AF composition may help to unravel the biochemical pathways underlying fetal development and could offer insight on the potential impact of maternal nutritional management on fetal growth regulation.

Novel antibacterial activity of β(2)-microglobulin in human amniotic fluid

An antibacterial protein (about 12 kDa) was isolated from human amniotic fluid through dialysis, ultrafiltration and C18 reversed-phase HPLC steps. Automated Edman degradation showed that the N-terminal sequence of the antibacterial protein was NH(2)-Ile-Gln-Arg-Thr-Pro-Lys-Ile-Gln-Val-Tyr-Ser-Arg-His-Pro-Ala-Glu-Asn-Gly-. The N-terminal sequence of the antibacterial protein was found to be identical to that of β(2)-microglobulin, a component of MHC class I molecules, which are present on all nucleated cells. Matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) revealed that the molecular mass of the antibacterial protein was 11,631 Da. This antibacterial protein, β(2)M, possessed potent antibacterial activity against pathogenic bacteria. Specially, antibacterial activity was observed in potassium buffer, and potassium ion was found to be critical for the antibacterial activity. Interestingly, the antibacterial action of β(2)M was associated with dissipation of the transmembrane potential, but the protein did not cause damage to the membrane that would result in SYTOX green uptake. In addition, stimulation of WISH amniotic epithelial cells with the bacterial endotoxin lipopolysaccharide (LPS) induced dose-dependent upregulation of β(2)M mRNA expression. These results suggest that β(2)M contributes to a self-defense response when amniotic cells are exposed to pathogens.

Identification and characterization of proteins in amniotic fluid that are differentially expressed before and after antenatal corticosteroid administration

OBJECTIVE

We sought to examine changes in the intraamniotic proteomic environment after the administration of antenatal corticosteroids to women with impending preterm delivery.

STUDY DESIGN

Amniotic fluid samples were collected at the time of clinically indicated amniocentesis before and within 7 days of administration of antenatal corticosteroids for impending preterm delivery (n = 12). Proteins differentially expressed before and after corticosteroids were identified by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. They were isolated, characterized, and quantified by fast protein liquid chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, in-gel tryptic digestion, immunodepletion assays, enzyme-linked immunosorbent assay, and electrospray ionization tandem mass spectrometry.

RESULTS

Five protein peaks of interest were identified and characterized, all of which were significantly decreased after antenatal corticosteroid administration. These included 2 isoforms of transthyretin, albumin, prothrombin fragment 2, and lumican.

CONCLUSION

Four proteins, identified and characterized in amniotic fluid, were differentially expressed with antenatal corticosteroid administration. These data may provide additional insight into the molecular mechanisms by which antenatal corticosteroids prevent neonatal complications.

A comparative evaluation of three washing procedures for minimizing exogenous trace element contamination in fetal scalp hair of various obstetric outcomes

A comparative evaluation of three washing methods for removing exogenous elemental contamination from fetal scalp hair is described. A total of 12 samples, including 6 from normal pregnancies and 6 from abruptio placentae (AP) cases, were used. Each was divided into four subsamples, with one left unwashed for comparison, while three were subjected to one of the three washing methods. The first consisted of agitating hair for 5 min in sequential and equal measures (30 ml) of acetone and water, followed by rinsing with acetone, and the process repeated twice. In the second and third, hair was agitated for 30 min in aqueous solutions of sodium lauryl sulfate (0.5%, w/v), and Triton X-100 (0.5%, v/v), respectively, followed by sequential rinsing with deionized water and acetone. After drying and microwave-assisted digestion in concentrated nitric acid, the subsamples' concentrations of zinc, copper, cadmium, lead, mercury and selenium were determined using inductively coupled mass spectrometry. All washed subsamples, irrespective of washing method used, had lower elemental concentrations than the corresponding, unwashed subsamples. These differences, taken as presumptive indicators of exogenous contamination, showed only small variations (<5%) between the three washing methods, irrespective of element, mode of delivery, and obstetric outcome. However, the contamination levels elicited by each of the three methods varied in magnitude according to individual elements, with those of copper being highest, followed by those of zinc, cadmium, mercury, selenium, and lead. They also varied according to obstetric outcome, being highest in the AP subsamples, while in the normal pregnancy group, copper and zinc contamination levels in the subsamples from neonates delivered by elective caesarean section were higher than in those from normal-delivery neonates. The data from this study suggest that the three washing methods used have comparable efficacies in removing exogenous elemental contamination from fetal hair, further inferring that it is probably a simple biological matrix to decontaminate. Possible contributory factors are discussed and contrasted with those affecting adult hair.

Inositol phosphoglycan P-type in healthy and preeclamptic pregnancies

An association between inositol phosphoglycan P-type (P-IPG) and preeclampsia has been demonstrated over recent years. This molecule can mediate many of the metabolic and growth promoting effects of insulin. Dysregulation of the mediator family is associated with insulin resistance. An increased concentration of P-IPG has been reported in preeclamptic placenta, although its precursor (GPI) was undetectable in those placental samples. Insulin administration, that induces P-IPG release in normal human placenta, was shown not to cause production/release of the mediator from preeclamptic placental tissue as a consequence of a disturbed insulin signalling. Amniotic fluid is enriched of this mediator, with further increase during preeclampsia. We have found that the fetus released increasing amounts of P-IPG in the urine between 13 and 18 weeks of gestation, reaching a plateau beyond 20 weeks. Cord blood of infants of preeclamptic mothers showed an increased content of soluble P-IPG compared to controls and to the mother.

Vaginal fluid urea and creatinine in diagnosis of premature rupture of membranes

OBJECTIVE

To evaluate the reliability of vaginal fluid urea and creatinine for the diagnosis of premature rupture of membranes (PROMs).

MATERIALS AND METHODS

A total of 139 pregnant women were recruited. Group I consisted of 47 patients with diagnosis of PROM confirmed by amniotic fluid pooling and nitrazine paper test. Group II consisted of 36 patients in whom diagnosis of PROM was suspected but unconfirmed by amniotic fluid pooling (+/-) and/or nitrazine paper test (+/-). Group III consisted of 56 pregnant women without any complaint or complication. All patients underwent speculum examination for amniotic fluid pooling, nitrazine paper test, vaginal washing fluid urea and creatinine sampling. One-way ANOVA test, Scheffe multiple comparison test and receiver operating characteristic curve analysis were used.

RESULTS

The mean vaginal fluid urea levels in group I, II, and III were 34.6 +/- 5.3, 2.4 +/- 5.3 and 1.3 +/- 6.2 mg/dl, respectively, where the difference was statistically significant (P < 0.001). The mean vaginal fluid creatinine concentrations of group I were, 1.5 +/- 0.3 mg/dl, found higher against the group II, 0.34 +/- 0.22 mg/dl, and group III, 0.28 +/- 0.23 mg/dl (P < 0.01). The sensitivity, specificity, positive predictivity, and negative predictivity were all 100% in detecting PROM by evaluation of vaginal fluid urea and creatinine concentration with a cut-off value of 12 and 0.6 mg/dl, respectively.

CONCLUSION

Vaginal washing fluid urea and creatinine determination for the diagnosis of PROM is a reliable, simple and rapid test.