Actual electrolyte intake during the first week of life and morbidity in very-low-birthweight infants.

AIM: To describe sodium and potassium intake, their sources and plasma concentrations, and the association between intake and morbidity in very-low-birthweight (VLBW, <1500 g) infants during the first week of life. METHODS: This retrospective cohort study comprised 951 VLBW infants born at <32 weeks. Infants were divided into three groups according to gestational age: 23-26 (n = 275), 27-29 (n = 433) and 30-31 (n = 243) weeks. Data on fluid management and laboratory findings were acquired from an electronic patient information system. RESULTS: The median sodium intake was highest in the 23-26 week group, peaking at 6.4 mmol/kg/day. A significant proportion of sodium derived from intravascular flushes; it reached 27% on day 1 in the 23-26 week group. High cumulative sodium intake in the first postnatal week was associated with weight gain from birth to day 8 in the 23-26 week group. High intake of sodium associated with an increased risk of surgically ligated patent ductus arteriosus (PDA), bronchopulmonary dysplasia and intraventricular haemorrhage, whereas low intake of potassium associated with an increased risk of PDA. CONCLUSION: Sodium intake in the most premature infants exceeded recommendations during the first postnatal week. Saline flushes accounted for a significant proportion of the sodium load.

Time of Delivery Contributes to Mortality and Morbidity in Preterm Infants.

INTRODUCTION: Knowledge about the time of birth and its impact on premature infants is essential when planning perinatal and neonatal care and resource allocation. We studied the time of birth and its contribution to early death and morbidity in preterm infants. METHODS: We explored the time and mode of birth of infants with birthweight of <1,500 g and gestational age of <32+0/7 weeks. Additionally, we divided the infants into three groups stratified by their time of birth, i.e., during office hours, evening, and nighttime and assessed associations between these groups and mortality and morbidity. RESULTS: The study comprised 1,610 infants of whom 156 (10%) died during their stay in neonatal intensive care unit. The highest number of deliveries occurred on Fridays (21%, n = 341/1,610), primarily due to high number of cesarean sections. Deliveries peaked on workdays at 10 a.m. and 2:00 p.m. Mortality was lowest among infants born on Fridays (6%, n = 21/341) and highest on Mondays (13%, n = 28/218). Intraventricular hemorrhage (IVH) (odds ratio [OR]: 1.50, 95% CI: 1.10-2.03, p = 0.010) and necrotizing enterocolitis (NEC) (OR: 2.11, 95% CI: 1.13-3.91, p = 0.019) were more common among infants born at nighttime. These associations attenuated after adjustment for covariates. CONCLUSION: Deliveries of premature infants peaked on Fridays. Mortality was lower among those born on Fridays, compared with Mondays. Many low-risk deliveries on Fridays may decrease, and the tendency to postpone high-risk deliveries to Mondays, increase the proportional risk of mortality. Indication of higher risk of IVH and NEC among infants born during nighttime may be due to different patient population.

Very low birthweight infants receive less enteral feeding than what is prescribed.

AIM: Feeding a very low birthweight (VLBW, <1500 g) infant is challenging. Our aims were to study how prescribed enteral feeding is implemented in VLBW infants and to identify factors associating with slow enteral feeding progression. METHODS: Our retrospective cohort included 516 VLBW infants born before 32 weeks of gestation during 2005-2013 and admitted to Children's Hospital, Helsinki, Finland, for at least the two first weeks of life. Nutritional data were collected from birth until the age of 14-28 days, depending on the length of stay. RESULTS: We found that enteral feeding progressed slower than recommended and implementation differed from the prescriptions, especially during the parenteral nutrition phase (milk intake 10-20 mL/kg/day): 71% [40-100], median [IQR], of the prescribed enteral milk was administered. The full prescribed amount was less likely administered if a higher volume of gastric residual was aspirated or if the infant did not pass stool during the same day. Longer opiate use, patent ductus arteriosus, respiratory distress syndrome and slower passage of the first meconium associated with slower enteral feeding progression. CONCLUSION: Enteral feeding of a VLBW infant is often not administered as prescribed, which possibly plays a significant role in the slow progression of enteral feeding.

Blood pressure changes during the first 24 hours of life and the association with the persistence of a patent ductus arteriosus and occurrence of intraventricular haemorrhage.

Very low birthweight (VLBW) infants are at risk of intraventricular haemorrhage (IVH) and delayed closure of ductus arteriosus. We investigated mean arterially recorded blood pressure (MAP) changes during the first day of life in VLBW infants as potential risk factors for a patent ductus arteriosus (PDA) and IVH. This retrospective cohort study exploring MAP changes during adaption and risk factors for a PDA and IVH comprised 844 VLBW infants admitted to the Helsinki University Children's Hospital during 2005-2013. For each infant, we investigated 600 time-points of MAP recorded 4-24 hours after birth. Based on blood pressure patterns revealed by a data-driven method, we divided the infants into two groups. Group 1 (n = 327, mean birthweight = 1019 g, mean gestational age = 28 + 1/7 weeks) consisted of infants whose mean MAP was lower at 18-24 hours than at 4-10 hours after birth. Group 2 (n = 517, mean birthweight = 1070 g, mean gestational age = 28 + 5/7 weeks) included infants with a higher mean MAP at 18-24 hours than at 4-10 hours after birth. We used the group assignments, MAP, gestational age at birth, relative size for gestational age, surfactant administration, inotrope usage, invasive ventilation, presence of respiratory distress syndrome or sepsis, fluid intake, and administration of antenatal steroids to predict the occurrence of IVH and use of pharmacological or surgical therapy for a PDA before 42 weeks of gestational age. Infants whose mean MAP is lower at 18-24 hours than at 4-10 hours after birth are more likely to undergo surgical ligation of a PDA (odds ratio = 2.1; CI 1.14-3.89; p = 0.018) and to suffer from IVH (odds ratio = 1.83; CI 1.23-2.72; p = 0.003).

Length of Nutritional Transition Associates Negatively with Postnatal Growth in Very Low Birthweight Infants.

Very low birthweight (VLBW, <1500 g) infants may be predisposed to undernutrition during the nutritional transition phase from parenteral to enteral nutrition. We studied the associations among the length of the transition phase, postnatal macronutrient intake, and growth from birth to term equivalent age in VLBW infants. This retrospective cohort study included 248 VLBW infants born before 32 weeks of gestation and admitted to the Children's Hospital, Helsinki, Finland during 2005-2013. Daily nutrient intakes were obtained from computerized medication administration records. The length of the transition phase correlated negatively with cumulative energy, protein, fat, and carbohydrate intake at 28 days of age. It also associated negatively with weight and head circumference growth from birth to term equivalent age. For infants with a long transition phase (over 12 d), the estimates (95% CI) for weight and head circumference z-score change from birth to term equivalent age were -0.3 (-0.56, -0.04) and -0.44 (-0.81, -0.07), respectively, in comparison to those with a short transition phase (ad 7 d). For VLBW infants, rapid transition to full enteral feeding might be beneficial. However, if enteral nutrition cannot be advanced, well-planned parenteral nutrition during the transition phase is necessary to promote adequate growth.

Early oxygen levels contribute to brain injury in extremely preterm infants.

BACKGROUND: Extremely low gestational age newborns (ELGANs) are at risk of neurodevelopmental impairments that may originate in early NICU care. We hypothesized that early oxygen saturations (SpO2), arterial pO2 levels, and supplemental oxygen (FiO2) would associate with later neuroanatomic changes. METHODS: SpO2, arterial blood gases, and FiO2 from 73 ELGANs (GA 26.4 ± 1.2; BW 867 ± 179 g) during the first 3 postnatal days were correlated with later white matter injury (WM, MRI, n = 69), secondary cortical somatosensory processing in magnetoencephalography (MEG-SII, n = 39), Hempel neurological examination (n = 66), and developmental quotients of Griffiths Mental Developmental Scales (GMDS, n = 58). RESULTS: The ELGANs with later WM abnormalities exhibited lower SpO2 and pO2 levels, and higher FiO2 need during the first 3 days than those with normal WM. They also had higher pCO2 values. The infants with abnormal MEG-SII showed opposite findings, i.e., displayed higher SpO2 and pO2 levels and lower FiO2 need, than those with better outcomes. Severe WM changes and abnormal MEG-SII were correlated with adverse neurodevelopment. CONCLUSIONS: Low oxygen levels and high FiO2 need during the NICU care associate with WM abnormalities, whereas higher oxygen levels correlate with abnormal MEG-SII. The results may indicate certain brain structures being more vulnerable to hypoxia and others to hyperoxia, thus emphasizing the role of strict saturation targets. IMPACT: This study indicates that both abnormally low and high oxygen levels during early NICU care are harmful for later neurodevelopmental outcomes in preterm neonates. Specific brain structures seem to be vulnerable to low and others to high oxygen levels. The findings may have clinical implications as oxygen is one of the most common therapies given in NICUs. The results emphasize the role of strict saturation targets during the early postnatal period in preterm infants.

Glucocorticoids, sodium transport mediators, and respiratory distress syndrome in preterm infants.

BACKGROUND: Antenatal glucocorticoids (GCs) reduce respiratory distress syndrome (RDS) in preterm infants and are associated with reduced lung liquid content. Our aim was to assess whether airway gene expression of mediators of pulmonary epithelial sodium and liquid absorption, and further, respiratory morbidity, associate with cord blood GC concentrations. METHODS: The study included 64 infants delivered <32 weeks gestation. Cortisol and betamethasone in umbilical cord blood were quantified with liquid chromatography-tandem mass spectrometry. The total GC concentration was calculated. Gene expression of the epithelial sodium channel (ENaC), Na,K-ATPase, and serum- and GC-inducible kinase 1 at <2 h and at 1 day postnatally in nasal epithelial cell samples was quantified with reverse transcription-polymerase chain reaction. The mean oxygen supplementation during the first 72 h was calculated. RESULTS: Concentrations of cord blood betamethasone and total GC were significantly lower in infants with RDS and correlated with mean oxygen supplementation. Expression of αENaC and α1- and ß1Na,K-ATPase at <2 h correlated with betamethasone and total GC concentrations. Expression of Na,K-ATPase was lower in infants with RDS. CONCLUSION: Enhancement of lung liquid absorption via increased expression of sodium transporters may contribute to the beneficial pulmonary effects of antenatal GCs. IMPACT: RDS is related to lower umbilical cord blood GC concentrations and lower airway expression of sodium transporters. In addition to the timing of antenatal GC treatment, resulting concentrations may be of importance in preventing RDS. Induction of sodium transport may be a factor contributing to the pulmonary response to antenatal GCs.

A triple-chamber parenteral nutrition solution was associated with improved protein intake in very low birthweight infants.

AIM: We evaluated the nutrient intakes of very low birthweight (VLBW) infants weighing less than 1500 g and tested the hypothesis that using a triple-chamber parenteral nutrition (PN) solution, containing lipids, glucose and amino acids, would improve protein intake. METHODS: This retrospective cohort study comprised 953 VLBW infants born in 2005-2013 at a gestational age of less than 32 + 0/7 weeks and admitted to the neonatal care unit at Helsinki Children's Hospital, Finland. The infants were divided into four groups according their birth year and PN regime. Nutrient intakes were obtained from computerised medication administration records. RESULTS: In 2012-2013, when a triple-chamber PN solution was used, infants were more likely to reach the target parenteral protein intake of 3.5 g/kg/d, and reach it 3-7 days earlier, compared with infants who received individual PN or standard two-in-one PN solutions in 2005-2011. In addition, infants in the triple-chamber group had the highest median energy intake (90 kcal/kg/d) during the first week. They also had higher median protein intakes in weeks one, two and three (3.1, 3.4 and 3.7 g/kg/d) than infants born in 2005-2011 (P < .05). CONCLUSION: Using a triple-chamber PN solution was associated with improved protein intake, and the protein target was more likely to be achieved.

Hidden sources like saline flushes make a significant contribution to the fluid intake of very low birthweight infants during the first postnatal week.

AIM: We examined actual fluid intake, and routes of administration, in very low birthweight (VLBW) infants during the first week of life in a neonatal intensive care unit. METHODS: This retrospective cohort study comprised 953 infants born at <32 weeks and 1500 g and treated at Helsinki University Children's Hospital from 2005 to 2013. All parenterally and enterally administered fluids, and their sources, were obtained from our patient information system. Infants were divided into three groups according to their gestational age: 23-26, 27-29 and 30-31 weeks. RESULTS: Fluid intake exceeded European guidelines during the first 3 days. On days 1-7, total fluid intake was highest in the most premature group (P < .001) and the median total fluid intake in this group peaked at 177 mL/kg/d (IQR 154-209) on day three. Intravascular flushes provided a considerable source of fluids, with the median intake in the most preterm group peaking at 26.4 mL/kg/d, which represented 15.6% of total fluid intake. CONCLUSION: During the first 3 days of life, our VLBW infants had a higher total fluid intake than the European guidelines. A considerable percentage came from hidden sources, such as saline flushes, which should be taken into account when prescribing fluids.

Activated mast cells induce endothelial cell apoptosis by a combined action of chymase and tumor necrosis factor-alpha.

OBJECTIVE: Activated mast cells (MCs) induce endothelial cell (EC) apoptosis in vitro and are present at sites of plaque erosions in vivo. To further elucidate the role of MCs in endothelial apoptosis and consequently in plaque erosion, we have studied the molecular mechanisms involved in MC-induced EC apoptosis. METHODS AND RESULTS: Primary cultures of rat cardiac microvascular ECs (RCMECs) and human coronary artery ECs (HCAECs) were treated either with rat MC releasate (ie, mediators released on MC activation), rat chymase and tumor necrosis factor-alpha (TNF-alpha), or with human chymase and TNF-alpha, respectively. MC releasate induced RCMEC apoptosis by inactivating the focal adhesion kinase (FAK) and Akt-dependent survival signaling pathway, and apoptosis was partially inhibited by chymase and TNF-alpha inhibitors. Chymase avidly degraded both vitronectin (VN) and fibronectin (FN) produced by the cultured RCMECs. In addition, MC releasate inhibited the activation of NF-kappaB (p65) and activated caspase-8 and -9. Moreover, in HCAECs, human chymase and TNF-alpha induced additive levels of apoptosis. CONCLUSIONS: Activated MCs induce EC apoptosis by multiple mechanisms: chymase inactivates the FAK-mediated cell survival signaling, and TNF-alpha triggers apoptosis. Thus, by inducing EC apoptosis, MCs may contribute to plaque erosion and complications of atherosclerosis.

Inhibition of smooth muscle cell proliferation by a chemically modified tetracycline.

INTRODUCTION: Chemically modified tetracyclines (CMTs) are a group of nonantimicrobial derivatives of tetracycline, which exert antiproliferative and anticollagenolytic properties. The molecular mechanisms, however, are poorly understood. MATERIALS AND METHODS: The effect of CMT-3 on cultured, subconfluent rat aortic smooth muscle cells (SMCs) was analyzed by [(3)H]-thymidine incorporation, counting cell numbers, and flow cytometry analysis. RESULTS: CMT-3 inhibited the incorporation of [(3)H]-thymidine and reduced the cell number dose-dependently, with approximately 60% inhibition at the maximal CMT-3 concentration used (20 mumol/l). CMT-3 decreased the SMC proportion in S-phase and gradually increased the proportion at G2/M. Initially, the proportion of cells in G1-phase increased and then gradually decreased back to baseline as the CMT-3 concentration increased. CMT-3 treatment of confluent SMCs for 24 h did not induce apoptosis. CONCLUSIONS: CMT-3 inhibited SMC proliferation by inducing cell cycle arrest at the G2/M restriction point. Nonetheless, CMT-3 did not induce SMC apoptosis.

Mast cell chymase induces smooth muscle cell apoptosis by disrupting NF-kappaB-mediated survival signaling.

Chymase released from activated mast cells induces apoptosis of vascular smooth muscle cells (SMCs) in vitro by degrading the pericellular matrix component fibronectin, so causing disruption of focal adhesion complexes and Akt dephosphorylation, which are necessary for cell adhesion and survival. However, the molecular mechanisms of chymase-mediated apoptosis downstream of Akt have remained elusive. Here, we show by means of RT-PCR, Western blotting, EMSA, immunocytochemistry and confocal microscopy, that chymase induces SMC apoptosis by disrupting NF-kappaB-mediated survival signaling. Following chymase treatment, the translocation of active NF-kappaB/p65 to the nucleus was partly abolished and the amount of nuclear p65 was reduced. Pretreatment of SMCs with chymase also inhibited LPS- and IL-1beta-induced nuclear translocation of p65. The chymase-induced degradation of p65 was mediated by active caspases. Loss of NF-kappaB-mediated transactivation resulted in downregulation of bcl-2 mRNA and protein expression, leading to mitochondrial swelling and release of cytochrome c. The apoptotic process involved activation of both caspase 9 and caspase 8. The results reveal that, by disrupting the NF-kappaB-mediated survival-signaling pathway, activated chymase-secreting mast cells can mediate apoptosis of cultured arterial SMCs. Since activated mast cells colocalize with apoptotic SMCs in vulnerable areas of human atherosclerotic plaques, they may participate in the weakening and rupture of atherosclerotic plaques.

Proteolysis of the pericellular matrix: a novel element determining cell survival and death in the pathogenesis of plaque erosion and rupture.

The 2 major general concepts about the cell biology of atherogenesis, growth of smooth muscle cells, and lipid accumulation in macrophages, ie, foam cell formation, have not been able to satisfactorily explain the genesis of acute coronary syndromes. Rather, the basic pathology behind the acute atherothrombotic events relates to erosion and rupture of unstable coronary plaques. At the cellular level, we now understand that a switch from cellular growth to cellular death, notably apoptosis, could be involved in turning at least some types of atherosclerotic plaques unstable. Because intimal cells require a proper matrix environment for normal function and survival, the vulnerability of an atherosclerotic plaque may critically depend on the integrity of the pericellular matrix of the plaque cells. In vitro studies have revealed that plaque-infiltrating inflammatory cells, such as macrophages, T-lymphocytes, and mast cells, by secreting a variety of proteases capable of degrading pericellular matrix components, induce death of endothelial cells and smooth muscle cells, and so provide a mechanistic explanation for inflammation-dependent plaque erosion and rupture. Thus, a novel link between inflammation and acute coronary syndromes is emerging. For a more explicit understanding of the role of proteases released by inflammatory cells in the conversion of a clinically silent plaque into a dangerous and potentially killing plaque, animal models of plaque erosion and rupture need to be established.

Regulation of smooth muscle cell growth, function and death in vitro by activated mast cells--a potential mechanism for the weakening and rupture of atherosclerotic plaques.

The fibrous cap of a lipid-containing atherosclerotic plaque consists of collagen produced by arterial smooth muscle cells (SMCs) of synthetic phenotype. A thick cap protects the lipid-rich core, whereas a thin cap predisposes it to rupture, with ensuing acute clinical complications, such as myocardial infarction. Among the pathological mechanisms leading to plaque weakening and rupture, one possibility is loss of the matrix-synthesizing SMCs. Indeed, caps of ruptured coronary plaques contain a reduced number of SMCs. In contrast, in such lesions, the number of activated inflammatory cells, such as mast cells, is increased, suggesting that they may regulate the SMC number. We have shown that heparin proteoglycans secreted by activated mast cells can efficiently inhibit proliferation of SMCs in vitro and reduce their ability to produce collagen. Chymase, a neutral serine protease secreted by activated mast cells, can also inhibit SMC-mediated collagen synthesis by a transforming growth factor-beta-dependent and -independent mechanism, and moreover, cause degradation of the collagen matrix by activating latent interstitial collagenase (MMP-1). Furthermore, chymase can induce SMC apoptosis by degrading the extracellular matrix component fibronectin necessary for SMC adhesion, with subsequent disruption of focal adhesions and loss of outside-in survival signaling. Thus, activated mast cells may participate in the weakening and rupture of atherosclerotic plaques by secreting mediators, such as heparin proteoglycans and chymase, which affect the growth, function and death of arterial SMCs.

Mast cell chymase induces smooth muscle cell apoptosis by a mechanism involving fibronectin degradation and disruption of focal adhesions.

OBJECTIVE: Chymase released from activated mast cells has been shown to induce apoptosis of vascular smooth muscle cells (SMCs) in vitro. The proteolytic activity of chymase is essential for the proapoptotic effect, but the mechanism of chymase-induced apoptosis has remained unknown. METHODS AND RESULTS: Here we show by means of FACS analysis, immunohistochemistry, and Western blotting that mast cell-derived chymase induces SMC apoptosis by a mechanism involving degradation of an extracellular matrix component, fibronectin (FN), with subsequent disruption of focal adhesions. The FN degradation products induced SMC apoptosis of similar magnitude and with similar changes in outside-in signaling, as did chymase. Sodium orthovanadate, an inhibitor of tyrosine phosphatases, inhibited the chymase-induced SMC apoptosis. Focal adhesion kinase (FAK), one of the key mediators of integrin-extracellular matrix interactions and cell survival, was rapidly degraded in the presence of chymase or FN degradation products. Loss of phosphorylated FAK (p-FAK) resulted in a rapid dephosphorylation of the p-FAK-dependent downstream mediator Akt. CONCLUSIONS: The results suggest that chymase-secreting mast cells can mediate apoptosis of neighboring SMCs through a mechanism involving degradation of pericellular FN and disruption of the p-FAK-dependent cell-survival signaling cascade.

Mast cell-mediated apoptosis of endothelial cells in vitro: a paracrine mechanism involving TNF-alpha-mediated down-regulation of bcl-2 expression.

Degranulated mast cells are present in the subendothelial space of eroded (de-endothelialized) coronary atheromas. Upon degranulation, mast cells secrete into the surrounding tissue an array of preformed and newly synthesized mediators, including proapoptotic molecules, such as chymase and TNF-alpha. In a co-culture system involving rat serosal mast cells and rat cardiac (microvascular) endothelial cells, we could show, by means of competitive RT-PCR, immunoblotting, immunocytochemistry, annexin staining, flow cytometry, and DNA-laddering, that stimulation of mast cells with ensuing degranulation rapidly (within 30 min) down-regulated the expression of both bcl-2 mRNA and protein, with subsequent induction of apoptosis in the endothelial cells. The major effect of bcl-2 down-regulation resided in the exocytosed granule remnants, a minor effect also being present in the granule remnant-free supernatant. No significant changes were observed in the expression levels of the pro-apoptotic protein, bax. The mast cell-mediated apoptotic effect was partially (70%) dependent on the presence of TNF-alpha and involved the translocation of cytochrome C from mitochondria into cytoplasm. These results are the first to show that one of the cell types present in the atherosclerotic plaques, namely the mast cell, by releasing both granule-remnant-bound and soluble TNF-alpha, may contribute to the erosion of atherosclerotic plaques by inducing apoptosis in adjacent endothelial cells. Published 2003 Wiley-Liss, Inc.