Effect of autologous umbilical cord blood transfusion in the development of retinopathy of prematurity: randomized clinical trial - study protocol.

Background: Currently, the treatment of anemia in preterm infants is based on packed red blood cell (RBC) transfusions from adult donors. Oxygen (O2) is mainly transported to the tissues bound to hemoglobin (Hb). In extremely low gestational age neonates (ELGANs), fetal hemoglobin (HbF), which has a higher affinity for O2, represents up to 95% of circulating hemoglobin. During the first month of life, the majority of ELGANs will require an adult-donor RBC transfusion causing HbF levels to rapidly drop. HbA releases 50% more oxygen in peripheral tissues than HbF. Increased release of O2 in the retina is one of the main factors related to the development of retinopathy of prematurity (ROP). Collecting umbilical cord blood and using autologous umbilical cord whole blood (UCB) transfusions would contribute to maintaining physiological HbF concentrations in newborns and avoid oxygen-in-excess derived damage. Methods: This is a randomized, double-blinded, multicenter clinical trial. ELGANs ≤28 weeks of gestational age will be randomized 1:1 to receive an autologous umbilical cord blood transfusion (intervention arm) or standard transfusion of packed RBC from an adult donor (control arm) to assess ROP development. Assuming a 50% reduction in ROP incidence, 134 patients (67 per group) will be recruited. When blood transfusion is indicated, the Blook Bank will supply UCB or RCB according to the patient's group. The primary endpoint is the incidence of any ROP. Secondary endpoints are assessessment of treatment safety, results of biomarkers related to ROP and its chronology, and urine oxidative stress markers. In addition, the cellular composition of umbilical cord blood and its relationship with prematurity-related pathologies will be analyzed. All patients will be followed-up to 24 months of corrected age to evaluate their neurodevelopment. Discussion: ROP is a major cause of irreversible blindness in preterm newborns. Transfusions with adult donor blood can lead to complications, including ROP. UCB transfusions offer advantages by maintaining physiological HbF levels and potentially optimizing postnatal development. Moreover, autologous UCB transfusion could reduce risks associated with heterologous blood products, although volume collection remains challenging. UCB contains growth factors and progenitor cells that may impact ROP.

Do Lower Levels of Fetal Hemoglobin in Preterm Infants Relate to Oxidative Stress?

Fetal hemoglobin (HbF) has a higher affinity to oxygen than adult hemoglobin, allowing for a slower oxygen transfer to peripheral tissue, creating a microenvironment conducive to adequate fetal development in utero. However, most preterm infants receive packed red blood cell transfusions from adult donors leading to a drastic nonphysiological descent of circulating HbF. We hypothesized that this drop could enhance oxygen delivery to peripheral tissues generating a hyperoxic pro-oxidant environment. To investigate this, we assessed differences in oxidative stress biomarkers determined in urine samples in a cohort of 56 preterm infants born <32 weeks' gestation. Median oxidative stress biomarkers were compared between patients with circulating HbF above or below median HbF levels using Wilcoxon rank sum test. Oxidative stress biomarkers were significantly higher in the group of patients with lower levels of HbF. This study provides the initial evidence indicating elevated levels of oxidative stress biomarkers in preterm neonates with lower HbF levels. Based on the results, we hypothesize that HbF may contribute to preventing free radical-associated conditions during the newborn period.

Analysis of Fractional Cerebral Oxygen Extraction in Preterm Infants during the Kangaroo Care.

INTRODUCTION: We aimed to investigate the cerebral fractional tissue oxygen extraction (FtOE) during kangaroo care (KC) in premature infants and compare cardiorespiratory stability and hypoxic or bradycardic events between KC and incubator care. METHODS: A single-center prospective observational study was carried out at the NICU of a level 3 perinatal center. Preterm infants <32 weeks gestational age were subjected to KC. Patients were subjected to continuous monitoring of regional cerebral oxygen saturation (rScO2), peripheral oxygen saturation (SpO2), and heart rate (HR) during KC, before KC (pre-KC), and after KC (post-KC). The monitoring data were stored and exported to MATLAB for synchronization and signal analysis including the calculation of the FtOE and events analysis (i.e., desaturations and bradycardias counts and anormal values). Furthermore, the event counts and the mean SpO2, HR, rScO2, and FtOE were compared between studied periods employing the Wilcoxon rank-sum test and the Friedman test, respectively. RESULTS: A total of forty-three KC sessions with their corresponding pre-KC and post-KC segments were analyzed. The distributions of the SpO2, HR, rScO2, and FtOE showed different patterns according to the respiratory support, but not differences between the studied periods were detected. Accordingly, no significant differences in monitoring events were evidenced. However, cerebral metabolic demand (FtOE) was significantly lower during KC compared with post-KC (p = 0.019). CONCLUSION: Premature infants remain clinically stable during KC. Moreover, cerebral oxygenation is significantly higher and cerebral tissular oxygen extraction is significantly lower during KC compared with incubator care in post-KC. No differences in HR and SpO2 were shown. This novel data analysis methodology could be expanded to other clinical situations.

Effects of Sepsis on Immune Response, Microbiome and Oxidative Metabolism in Preterm Infants.

This is a narrative review about the mechanisms involved in bacterial sepsis in preterm infants, which is an illness with a high incidence, morbidity, and mortality. The role of the innate immune response and its relationship with oxidative stress in the pathogenesis are described as well as their potential implementation as early biomarkers. Moreover, we address the impact that all the mechanisms triggered by sepsis have on the dysbiosis and the changes on neonatal microbiota.

Longitudinal perturbations of plasma nuclear magnetic resonance profiles in neonatal encephalopathy.

BACKGROUND: Neonatal encephalopathy (NE) is a major cause of mortality and severe neurological disability in the neonatal period and beyond. We hypothesized that the degree of brain injury is reflected in the molecular composition of peripheral blood samples. METHODS: A sub-cohort of 28 newborns included in the HYPOTOP trial was studied. Brain injury was assessed by magnetic resonance imaging (MRI) once per patient and neurodevelopment at 24 months of age was evaluated using the Bayley III Scales of Infant and Toddler Development. The nuclear magnetic resonance (NMR) profile of 60 plasma samples collected before, during, and after cooling was recorded. RESULTS: In total, 249 molecular features were quantitated in plasma samples from newborns and postnatal age showed to affect detected NMR profiles. Lactate, beta-hydroxybutyrate, pyruvate, and three triglyceride biomarkers showed the ability to discern between different degrees of brain injury according to MRI scores. The prediction performance of lactate was superior as compared to other clinical and biochemical parameters. CONCLUSIONS: This is the first longitudinal study of an ample compound panel recorded by NMR spectroscopy in plasma from NE infants. The serial determination of lactate confirms its solid position as reliable candidate biomarker for predicting the severity of brain injury. IMPACT: The use of nuclear magnetic resonance (NMR) spectroscopy enables the simultaneous quantitation of 249 compounds in a small volume (i.e., 100 µL) of plasma. Longitudinal perturbations of plasma NMR profiles were linked to magnetic resonance imaging (MRI) outcomes of infants with neonatal encephalopathy (NE). Lactate, beta-hydroxybutyrate, pyruvate, and three triglyceride biomarkers showed the ability to discern between different degrees of brain injury according to MRI scores. Lactate is a minimally invasive candidate biomarker for early staging of MRI brain injury in NE infants that might be readily implemented in clinical guidelines for NE outcome prediction.

Early molecular markers of ventilator-associated pneumonia in bronchoalveolar lavage in preterm infants.

INTRODUCTION: Ventilator-associated pneumonia (VAP) constitutes a serious nosocomial infection. Our aim was to evaluate the reliability of cytokines and oxidative stress/inflammation biomarkers in bronchoalveolar lavage fluid (BALF) and tracheal aspirates (TA) as early biomarkers of VAP in preterm infants. METHODS: Two cohorts were enrolled, one to select candidates and the other for validation. In both, we included preterms with suspected VAP, according to BALF culture, they were classified into confirmed VAP and no VAP. Concentration of 16 cytokines and 8 oxidative stress/inflammation biomarkers in BALF and TA was determined in all patients. RESULTS: In the first batch, IL-17A and TNF-α in BALF, and in the second one IL-10, IL-6, and TNF-α in BALF were significantly higher in VAP patients. BALF TNF-α AUC in both cohorts was 0.86 (sensitivity 0.83, specificity 0.88). No cytokine was shown to be predictive of VAP in TA. A statistically significant increase in the VAP group was found for glutathione sulfonamide (GSA) in BALF and TA. CONCLUSIONS: TNF-α in BALF and GSA in BALF and TA were associated with VAP in preterm newborns; thus, they could be used as early biomarkers of VAP. Further studies with an increased number of patients are needed to confirm these results. IMPACT: We found that TNF-α BALF and GSA in both BALF and TA are capable of discriminating preterm infants with VAP from those with pulmonary pathology without infection. This is the first study in preterm infants aiming to evaluate the reliability of cytokines and oxidative stress/inflammation biomarkers in BALF and TA as early diagnostic markers of VAP. We have validated these results in two independent cohorts of patients. Previously studies have focused on full-term neonates and toddlers and determined biomarkers mostly in TA, but none was exclusively conducted in preterm infants.

Direct Derivatization in Dried Blood Spots for Oxidized and Reduced Glutathione Quantification in Newborns.

The glutathione (GSH)-to-glutathione disulfide (GSSG) ratio is an essential node contributing to intracellular redox status. GSH/GSSG determination in whole blood can be accomplished by liquid chromatography-mass spectrometry (LC-MS) after the derivatization of GSH with N-ethylmaleimide (NEM). While this is feasible in a laboratory environment, its application in the clinical scenario is cumbersome and therefore ranges reported in similar populations differ noticeably. In this work, an LC-MS procedure for the determination of GSH and GSSG in dried blood spot (DBS) samples based on direct in situ GSH derivatization with NEM of only 10 µL of blood was developed. This novel method was applied to 73 cord blood samples and 88 residual blood volumes from routine newborn screening performed at discharge from healthy term infants. Two clinical scenarios simulating conditions of sampling and storage relevant for routine clinical analysis and clinical trials were assessed. Levels of GSH-NEM and GSSG measured in DBS samples were comparable to those obtained by liquid blood samples. GSH-NEM and GSSG median values for cord blood samples were significantly lower than those for samples at discharge. However, the GSH-NEM-to-GSSG ratios were not statistically different between both groups. With DBS testing, the immediate manipulation of samples by clinical staff is reduced. We therefore expect that this method will pave the way in providing an accurate and more robust determination of the GSH/GSSG values and trends reported in clinical trials.

Neurodevelopmental Outcome and Epigenetic Changes at 2 Years Associated with the Oxygen Load Received upon Postnatal Stabilization: A Pilot Study.

INTRODUCTION: The oxygen load provided to preterm infants during postnatal stabilization caused significant modifications of DNA methylation in the preterm epigenome. We aimed to assess if there was an association between DNA methylation changes and neurodevelopmental outcomes. METHODS: Preterm infants were followed until 2 years after birth. Dried blood spots were processed, and DNA methylation was measured using the MassARRAY technology of Sequenom. We selected specific genes that corresponded to differentially methylated CpG sites that correlated with the oxygen load at 2 h after birth. Neurodevelopmental outcome was blindly assessed using Bayley-III scale. RESULTS: Of 32 eligible patients, we completed the methylation analysis in 19 patients and the neurodevelopmental evaluation in 22. Comparison of differential methylation analysis between time 0 (cord blood) and 2 h after birth showed 74 significant CpGs, out of which 14 correlated with the oxygen load received at birth. Out of these 14 genes, only TRAPPC9 showed statistically significant differences at 2 years of age between the infants who received >500 mL versus <500 mL O2/kg. Premature who received >500 mL O2/kg showed significantly lower motor composite scores. DISCUSSION/CONCLUSIONS: Premature who received higher oxygen load scored lower motor composite scores and showed a hypermethylation pattern of TRAPPC9 at 2 years of age. TRAPPC9 mutations are associated with neurodevelopmental delay and intellectual disability, so changes in the CpG methylation of this gene and its subsequent expression alteration can produce a similar phenotype. Further studies with a greater sample size are needed to confirm these findings.

Impact of Kangaroo Care on Premature Infants' Oxygenation: Systematic Review.

INTRODUCTION: Kangaroo care (KC) is defined by the World Health Organization as a method of care consisting in putting premature infants or newborns in skin-to-skin contact with their parents. KC is an effective method of promoting health and well-being of infants and their families. Physiological stability during KC has been widely analyzed, however with controversial results. METHODS: A systematic review was conducted. Electronic databases searched included MEDLINE, Embase, CINAHL, and Scopus. Two authors independently reviewed and extracted information using a data extraction form. The methodological quality of the observational studies was assessed using "STROBE" and the "Cochrane Collaboration tool" for randomized controlled trials. The physiological monitoring parameters included were heart rate (HR), arterial oxygen saturation (SpO2), regional cerebral oxygen saturation (rScO2), and fractional oxygen extraction (FtOE). RESULTS: A total of 345 articles were identified. First, 302 articles were excluded by title and then 34 articles after full-text analysis. Finally, a total of 25 studies were included. Physiological parameters monitored (HR, SpO2, rScO2, and FtOE) showed no significant changes at different study periods: pre-KC, during KC, and post-KC. CONCLUSIONS: We conclude that stable preterm infants receiving or not respiratory support show no significant differences in HR, SpO2, FtOE during KC compared to routine incubator care. rScO2 remains stable during KC with slight upward trend. Further studies with a higher level of methodological quality are needed to confirm these findings.

GC-MS analysis of short chain fatty acids and branched chain amino acids in urine and faeces samples from newborns and lactating mothers.

BACKGROUND: Short chain fatty acids (SCFAs) and branched chain amino acids (BCAAs) are frequently determined in faeces, and widely used as biomarkers of gut-microbiota activity. However, collection of faeces samples from neonates is not straightforward, and to date levels of these metabolites in newborn's faeces and urine samples have not been described. METHODS: A targeted gas chromatography - mass spectrometry (GC-MS) method for the determination of SCFAs and BCAAs in both faeces and urine samples has been validated. The analysis of 210 urine and 137 faeces samples collected from preterm (PI), term infants (TI) and their mothers was used to report faecal and urinary SCFA and BCAA levels in adult and neonatal populations. RESULTS: A significant correlation among five SCFAs and BCAAs in faeces and urine samples was observed. Reference ranges of SCFAs and BCAAs in mothers, PI and TI were reported showing infant's lower concentrations in faeces and higher concentrations in urine. CONCLUSION: This method presents a non-invasive approach for the simultaneous assessment of SCFAs and BCAAs in faecal and urine samples and the results will serve as a knowledge base for future experiments that will focus on the study of the impact of nutrition on the microbiome of lactating mothers and their infants.

Oxygen saturation and heart rate in healthy term and late preterm infants with delayed cord clamping.

Blood oxygen in the fetus is substantially lower than in the newborn infant. In the minutes after birth, arterial oxygen saturation rises from around 50-60% to 90-95%. Initial respiratory efforts generate negative trans-thoracic pressures that drive liquid from the airways into the lung interstitium facilitating lung aeration, blood oxygenation, and pulmonary artery vasodilatation. Consequently, intra- (foramen ovale) and extra-cardiac (ductus arteriosus) shunting changes and the sequential circulation switches to a parallel pulmonary and systemic circulation. Delaying cord clamping preserves blood flow through the ascending vena cava, thus increasing right and left ventricular preload. Recently published reference ranges have suggested that delayed cord clamping positively influenced the fetal-to-neonatal transition. Oxygen saturation in babies with delayed cord clamping plateaus significantly earlier to values of 85-90% than in babies with immediate cord clamping. Delayed cord clamping may also contribute to fewer episodes of brady-or-tachycardia in the first minutes after birth, but data from randomized trials are awaited. IMPACT: Delaying cord clamping during fetal to neonatal transition contributes to a significantly earlier plateauing of oxygen saturation and fewer episodes of brady-and/or-tachycardia in the first minutes after birth. We provide updated information regarding the changes in SpO2 and HR during postnatal adaptation of term and late preterm infants receiving delayed compared with immediate cord clamping. Nomograms in newborn infants with delayed cord clamping will provide valuable reference ranges to establish target SpO2 and HR in the first minutes after birth.

Transcriptome profiles discriminate between Gram-positive and Gram-negative sepsis in preterm neonates.

BACKGROUND: Genome-wide expression profiles have been previously employed as clinical research diagnostic tools for newborn sepsis. We aimed to determine if transcriptomic profiles could discriminate between Gram-positive and Gram-negative bacterial sepsis in preterm infants. METHODS: Prospective, observational, double-cohort study was conducted in very low birth weight infants with clinical signs and culture-positive sepsis. Blood samples were collected when clinical signs became apparent. Total RNA was processed for transcriptomic analysis. Results were validated by both reverse-transcription polymerase chain reaction and a mathematical model. RESULTS: We included 25 septic preterm infants, 17 with Gram-positive and 8 with Gram-negative bacteria. The principal component analysis identified these two clusters of patients. We performed a predictive model based on 21 genes that showed an area under the receiver-operating characteristic curve of 1. Eight genes were overexpressed in Gram-positive septic infants: CD37, CSK, MAN2B2, MGAT1, MOB3A, MYO9B, SH2D3C, and TEP1. The most significantly overexpressed pathways were related to metabolic and immunomodulating responses that translated into an equilibrium between pro- and anti-inflammatory responses. CONCLUSIONS: The transcriptomic profile allowed identification of whether the causative agent was Gram-positive or Gram-negative bacteria. The overexpression of genes such as CD37 and CSK, which control cytokine production and cell survival, could explain the better clinical outcome in sepsis caused by Gram-positive bacteria. IMPACT: Transcriptomic profiles not only enable an early diagnosis of sepsis in very low birth weight infants but also discriminate between Gram-positive and Gram-negative bacteria as causative agents. The overexpression of some genes related to cytokine production and cell survival could explain the better clinical outcome in sepsis caused by Gram-positive bacteria, and could lead us to a future, targeted therapy.

Non-invasive monitoring of saliva can be used to identify oxidative stress biomarkers in preterm and term newborn infants.

AIM: The aim of this study was to appraise the feasibility and reproducibility of applying a validated analytical method to determine salivary oxidative stress biomarkers in newborn infants. METHODS: Prospective observational single-centre study was carried out in level III neonatal intensive care unit. Eligible patients were preterm infants and healthy full-term newborn infants. Salivary samples were analysed in the chromatographic system. RESULTS: A total of 23 premature newborn infants and 13 full-term newborns were included. We analysed salivary levels of oxidative stress biomarkers for 5-F2t isoprostane, 15-E2t isoprostane, prostaglandin E2 and prostaglandin F2α. The multivariate predictive model showed a positive association between female and 5-F2t isoprostonae, and between female sex and prostglandin F2α. In addition, we found a positive association between gestational age and levels of prostaglandin E2 . Furthermore, in the premature group, we found a positive association between the inspired fraction of oxygen and levels of prostaglandin G2 . CONCLUSION: We identified and determined lipid peroxidation biomarkers in term and preterm newborn infants' saliva using specific and validated mass spectrometry technology.

Preventive bundle approach decreases the incidence of ventilator-associated pneumonia in newborn infants.

OBJECTIVE: We hypothesized that the implementation of evidence-based interventions shaping a bundle approach could significantly reduce the incidence of ventilator-associated pneumonia (VAP) in the neonatal intensive care unit. STUDY DESIGN: We conducted a prospective observational cohort study including neonates undergoing mechanical ventilation >48 h. VAP rate and endotracheal intubation ratio were compared before (pre-period) and after (post-period) applying VAP prevention bundle strategies. RESULT: One hundred seventy-four neonates were included in pre-period (30 months) and 106 in post-period (17 months). Demographic characteristics were comparable and device use ratios were similar. Twenty-eight VAP episodes were diagnosed, 25 in the first period and 3 after the implementation of prevention bundle. This represents a reduction in the incidence rate from 11.79 to 1.93 episodes/1000 ventilator days (p < 0.01). CONCLUSION: The implementation of an educational evidence-based program using a bundle approach to prevent VAP has shown a statistically significant reduction in its incidence density.

DNA Methylation Analysis to Unravel Altered Genetic Pathways Underlying Early Onset and Late Onset Neonatal Sepsis. A Pilot Study.

Background: Neonatal sepsis is a systemic condition widely affecting preterm infants and characterized by pro-inflammatory and anti-inflammatory responses. However, its pathophysiology is not yet fully understood. Epigenetics regulates the immune system, and its alteration leads to the impaired immune response underlying sepsis. DNA methylation may contribute to sepsis-induced immunosuppression which, if persistent, will cause long-term adverse effects in neonates. Objective: To analyze the methylome of preterm infants in order to determine whether there are DNA methylation marks that may shed light on the pathophysiology of neonatal sepsis. Design: Prospective observational cohort study performed in the neonatal intensive care unit (NICU) of a tertiary care center. Patients: Eligible infants were premature ≤32 weeks admitted to the NICU with clinical suspicion of sepsis. The methylome analysis was performed in DNA from blood using Infinium Human Methylation EPIC microarrays to uncover methylation marks. Results: Methylation differential analysis revealed an alteration of methylation levels in genomic regions involved in inflammatory pathways which participate in both the innate and the adaptive immune response. Moreover, differences between early and late onset sepsis as compared to normal controls were assessed. Conclusions: DNA methylation marks can serve as a biomarker for neonatal sepsis and even contribute to differentiating between early and late onset sepsis.

Expired Tidal Volume and Respiratory Rate During Postnatal Stabilization of Newborn Infants Born at Term via Cesarean Delivery.

Objective: To retrieve evolving respiratory measures in the first minutes after birth in normal neonates born at term using a respiratory function monitor. Study design: We evaluated newborn babies delivered at term via cesarean after uncomplicated pregnancies. Immediately after birth, a respiratory function monitor with an adapted flowmeter and a face mask were applied at 2, 5, and 10 minutes after birth for 90 seconds in each period. We analyzed expired and inspired tidal volume, respiratory rate (RR), percentage of leakage, and number of analyzed breaths in each individual infant's recording using a respiratory research software. Results: A total of 243 infants completed the study. The final data set included 59 058 (48.35%) valid observations for each of the variables representing the analysis of 32 801 breaths. With these data, we constructed a reference range with 10th, 25th, 50th, 75th, and 90th percentiles for expired tidal volume and RR. Tidal volumes plateaued earlier in female than in male infants. No correlation with delayed cord clamping, gestational age, maternal morbidity, or indication for cesarean delivery were established. Conclusions: We have constructed a reference range with percentiles for inspired and expired tidal volumes and RR in newborn babies born at term for the first 10 minutes after birth. Reference ranges can be employed for research and can be useful in the clinical setting to guide positive pressure ventilation in the delivery room.

Suturas adhesivas mediante cianoacrilato en drenajes pleurales de prematuros / Adhesive sutures using cyanoacrylate in pleural drains of premature infants

No disponible

Oxygen Supplementation During Preterm Stabilization and the Relevance of the First 5 min After Birth.

Fetal to neonatal transition entails cardiorespiratory, hemodynamic, and metabolic changes coinciding with the switch from placental to airborne respiration with partial pressures of oxygen of 4-5 kPa in utero raising to 8-9 kPa ex utero in few minutes. Preterm infants have immature lung and antioxidant defense system. Very preterm infants (<32 weeks' gestation) frequently require positive pressure ventilation and oxygen to establish lung aeration, a functional residual capacity, and overcome a tendency toward hypoxemia and bradycardia in the first minutes after birth. Recent studies have shown that prolonged bradycardia (heart rate <100 beats per minute) and/or hypoxemia (oxygen saturation <80%) are associated with increased mortality and/or intracranial hemorrhage. However, despite the accumulated evidence, the way in which oxygen should be supplemented in the first minutes after birth still has not yet been clearly established. The initial inspired fraction of oxygen and its adjustment within a safe arterial oxygen saturation range measured by pulse oximetry that avoids hyper-or-hypoxia is still a matter of debate. Herewith, we present a current summary aiming to assist the practical neonatologist who has to aerate the lung and establish an efficacious respiration in very preterm infants in the delivery room.