[The content of Clara's cells protein in highly premature newborns with respiration disorders]

The study was carried out to analyze the content of Clara's cells protein in highly premature newborns with respiration disorders in neonatal period. The sample of 106 premature newborns of gestational age 26-32 weeks and body mass at birth 660-1500 g was examined. The concentration of Clara's cells protein in bronchoalveolar liquid and blood serum was higher in patients with inborn pneumonia as compared with children with respiratory distress syndrome. The low content Clara's cells protein in highly premature newborns with pneumonia was related with subsequent development of bronchopulmonary dysplasia.

Determination of selenium in serum samples of preterm newborn infants with bronchopulmonary dysplasia using a validated hydride generation system

Bronchopulmonary dysplasia (BPD), also known as chronic lung disease, is one of the most challenging complications in premature newborn infants. Selenium plays a role in antioxidant system by protecting cell membranes and neutralizing the deleterious effects of free radicals. The aim of this study was to determine the relationship between selenium concentration and incidence of bronchopulmonary dysplasia using a validated analytical method. Umbilical cord blood and blood samples 30 days after the birth were collected from 38 preterm newborn infants with gestation age of 32 weeks or less, and the separated serums were kept at -70°C until analysis time. Selenium concentration of serum was determined using an atomic absorption spectrophotometer. The method was validated on the basis of standard validation techniques. The analytical method was linear in the range of 1 to 500 μg/L with the limit of detection of 0.4 μg/L. Samples were collected from 38 infants whose gestation age was 32 weeks or less. The blood samples were collected from the umbilical cord blood at birth in 19 cases. In 25 cases, blood samples were collected 1 month after birth. Of the 15 patients diagnosed with BPD, 10 were boys (p = 0.02). The mean serum selenium concentration was not different at birth between patients with and without BPD, but it was significantly lower at 30 days after birth in patients with BPD (38.5 ± 14.1vs. 45.4 ± 18.7 μg/L, p = 0.02). Preterm newborn infants with BPD had lower serum selenium concentrations 1 month after birth.

Circulating endothelial progenitor cells in premature infants: is there an association with premature birth complications?

BACKGROUND

The most common morbidities in preterm infants are associated with vascular pathology. Endothelial progenitor cells (EPCs) have been implicated in repair of the vasculature, but their role in the pathogenesis of prematurity complications is not clear.

OBJECTIVES

We prospectively investigated an association between the number of EPCs circulating in blood during delivery as well as 2 and 6 weeks afterwards, the level of growth factors regulating their migration/homing, and the incidence of premature birth complications.

PATIENTS AND METHODS

The study groups consisted of 90 preterm and 52 full-term infants. Early-EPCs (CD133+CD34+CD144+) and late-EPCs (CD133-CD34+CD144+) were analysed in cord blood (CB) and peripheral blood (PB).

RESULTS

We found higher early- and late-EPC counts in the CB of premature infants compared with full-term babies. The number of circulating early- and late-EPCs was inversely associated with the Apgar score of preterm infants. A positive association between the early-EPC count and the risk of respiratory distress syndrome, retinopathy of prematurity, bronchopulmonary dysplasia, and infections was found. Nevertheless, multivariate analysis revealed that a higher number of EPCs was not an independent predictor of prematurity complications, which were directly related to lower gestational age. The EPC count in full-term infants maintained a constant, relatively low level over the 6-week follow-up, whereas the EPC population in preterm infants gradually decreased during this period. Furthermore, the number of CB late-EPCs in preterm infants positively correlated with VEGF concentration.

CONCLUSIONS

EPCs may play a considerable role in vascular development in preterm infants.

Respiratory disease and early serum S100A12 changes in very premature infants

AIM

The role of granulocyte-specific S100A12, a marker for inflammatory disorders, in newborn lung disease is unknown. We compared postnatal blood S100A12 concentrations against respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD).

METHODS

Blood samples from 92 newborns were collected on admission, 12 h, day 1, day 3-4 and day 7, and analysed for S100A12. IL-8 and IL-6 were assayed in 52 infants.

RESULTS

Infants with RDS were significantly more premature (median 27 vs. 34 weeks), more likely to receive antenatal corticosteroids (84% vs. 26%) and have lower neutrophil counts (median 2.4 vs. 3.8 × 10(9) /L) at admission. S100A12 levels peaked during the first day and were significantly lower in preterm infants with RDS compared to those without (median 250 vs. 616 ng/mL at 12 h, 281 vs. 828 ng/mL day 1, respectively). S100A12 levels were low among the 35 very preterm infants (24-29 week gestation) regardless of the presence of BPD (285 vs. 288 ng/mL on day 1). In comparison, IL-8 and IL-6 levels were not different between groups.

CONCLUSION

Plasma S100A12 is low in infants with RDS, possibly because of gestationally related differences in neutrophil response or to the effects of antenatal corticosteroids. It is therefore not a useful marker of BPD development.

L-citrulline attenuates arrested alveolar growth and pulmonary hypertension in oxygen-induced lung injury in newborn rats

Bronchopulmonary dysplasia (BPD) is characterized by arrested alveolar development and complicated by pulmonary hypertension (PH). NO promotes alveolar growth. Inhaled NO (iNO) ameliorates the BPD phenotype in experimental models and in some premature infants. Arginosuccinate synthetase (ASS) and arginosuccinate lyase (ASL) convert L-citrulline to L-arginine; L-citrulline is regenerated during NO synthesis from L-arginine. Plasma levels of these NO precursors are low in PH. We hypothesized that L-citrulline prevents experimental O2-induced BPD in newborn rats. Rat pups were assigned from birth through postnatal day (P) 14 to room air (RA), RA + L-citrulline, 95% hyperoxia (BPD model), and 95%O2 + L-citrulline. Rat pups exposed to hyperoxia had fewer and enlarged air spaces and decreased capillary density, mimicking human BPD. This was associated with decreased plasma L-arginine and L-citrulline concentrations on P7. L-citrulline treatment significantly increased plasma L-arginine and L-citrulline concentrations and increased ASL protein expression in hyperoxia. L-citrulline preserved alveolar and vascular growth in O2-exposed pups and decreased pulmonary arterial medial wall thickness (MWT) and right ventricular hypertrophy (RVH). Increased lung arginase (ARG) activity in O2-exposed pups was reversed by L-citrulline treatment. L-citrulline supplementation prevents hyperoxia-induced lung injury and PH in newborn rats. L-citrulline may represent a novel therapeutic alternative to iNO for prevention of BPD.

[Relationship between serum estradiol levels in the early postnatal period and the occurrence of hyaline membrane disease and bronchopulmonary dysplasia in neonates]

OBJECTIVE

This study examined the changes of serum levels of estradiol during the early postnatal period in neonates in order to investigate the possible relationship between the serum estradiol levels and the occurrence of pulmonary hyaline membrane disease (HMD) and bronchopulmonary dysplasia (BPD).

METHODS

Fifty-nine premature infants with the gestational age between 26 and 32 weeks and 61 full-term infants with the gestational ages between 37 and 42 weeks were enrolled. Serum levels of estradiol were measured on postnatal days 1, 3 and 7.

RESULTS

Serum levels of estradiol decreased rapidly after birth in both premature and term infants and there were significant differences among different postnatal ages groups. However, there were no significant differences in the serum estradiol levels between the premature and term groups on postnatal days 1, 3 and 7. Serum estradiol levels measured in premature infants with HMD were not statistically different from those in premature infants without HMD on all time points. Serum estradiol levels in premature infants with BPD were higher than those in premature infants without BPD on postnatal day 3, but there were no noticeable differences on postnatal days 1 and 7.

CONCLUSIONS

Serum estradiol levels decline rapidly within 7 days after birth in both premature and term infants. Serum estradiol levels in the early postnatal period are not associated with the occurrence of HMD and BPD, suggesting that serum estradiol in the early postnatal period can not be used as a marker for predicting the development of HMD and BPD.

Circulating endothelial progenitor cells and diseases of the preterm infant

During the last decade, multiple techniques have been developed to isolate and quantify human endothelial progenitor cells (EPCs). In parallel, a number of studies have applied these methodologies to investigate the number and function of circulating EPCs in adult diseases characterized by vascular dysfunction. However, very little is known about different subtypes of EPCs during gestation, during the neonatal age or in neonatal diseases. Initial evidence supports the hypothesis that circulating angiogenic cells may play an important role during development, and attention has particularly focused in clarifying the function of EPCs in lung vascular development, and the role of the impairment of EPC mobilization and homing in hyperoxia-induced lung injury characteristic of bronchopulmonary dysplasia. Among different subtypes of EPCs, both the role of angiogenic mononuclear cells (triple-positive CD34+CD133+VEGFR-2+ cells and colony forming unit-Hill cells) and endothelial colony forming cells (ECFCs) in physiological vascular development and during neonatal diseases need to be elucidated. A better understanding of EPC biology during gestation, during the neonatal age and in preterm infants will unravel the pathologic basis of bronchopulmonary dysplasia and other preterm and term neonatal diseases characterized by a prominent defect in vascular growth, including retinopathy of prematurity and persistent pulmonary hypertension of the newborn.

Brain-derived neurotrophic factor in infants <32 weeks gestational age: correlation with antenatal factors and postnatal outcomes

Neurotrophins (NTs) play important roles in brain growth and development. Cord blood (CB) brain-derived neurotrophic factor (BDNF) concentrations increase with gestational age but data regarding postnatal changes are limited. We measured BDNF concentrations after birth in 33 preterm infants <32-wk gestation. Serum was collected at birth (CB), at day 2, between day 6 and 10 (D6), at day 30 (D30), and at day 60 (D60). BDNF concentrations fell on D2 (p = 0.03), recovered by D6 (p = 0.10), and continued to rise thereafter at D30 (p = 0.06) and D60 (p = 0.01) compared with CB. CB BDNF concentrations positively correlated with duration of rupture of membranes (r = 0.43, p = 0.04). Antenatal steroids (ANS, p = 0.02), postnatal steroids (PNS, p = 0.04), and retinopathy of prematurity (ROP, p = 0.02) were identified as significant factors in multivariate analyses. The median (25-75th interquartile range) CB BDNF concentrations were higher in infants who received a complete course ANS compared with those who received a partial course [1461 (553-2064) versus 281 (171-536) pg/mL, p = 0.04]. BDNF concentrations negatively correlated with the use of PNS at D30 (r = -0.53, p = 0.002) and at D60 (r = -0.55, p = 0.009). PNS use was associated with reduced concentrations of BDNF at D30 [733 (101-1983) versus 2224 (1677- 4400) pg/mL, p = 0.004] and at D60 [1149 (288-2270) versus 2560 (1337-5166) pg/mL, p = 0.01]. BDNF concentrations on D60 in infants who developed ROP (n = 16) were lower than those who did not develop ROP (n = 7) [1417 (553-2540) versus 3593 (2620-7433) pg/mL, respectively, p = 0.005]. Our data suggests that BDNF concentrations rise beyond the first week of age. BDNF concentrations correlate with factors that influence neurodevelopment outcomes.

MMP-9 and TIMP-1 in the cord blood of premature infants developing BPD

We investigated matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) levels in the cord blood of 29 premature infants who were <30 weeks gestation. One, 8, and 14 infants developed severe, moderate and mild bronchopulmonary dysplasia (BPD), respectively, and 6 did not. MMP-9 and TIMP-1 levels in the cord blood were determined by ELISA. MMP-9/TIMP-1 ratios in the cord blood of infants who developed severe or moderate BPD (n = 9) were significantly higher than those who developed mild BPD or did not develop BPD (n = 20; P = 0.015). Multivariate linear regressions demonstrated that MMP-9 levels and MMP-9/TIMP-1 ratios in the cord blood of the premature infants correlated with the oxygen supplementation period (r = 0.58, P = 0.003 and r = 0.41, P = 0.030, respectively). The MMP-9 levels and MMP-9/TIMP-1 ratios correlated with the severity of maternal chorioamnionitis (both trend P = 0.006). The MMP-9 levels and MMP-9/TIMP-1 ratios in the cord blood may be related to the pathogenesis and severity of BPD and maternal chorioamnionitis.

Effect of oestradiol and progesterone replacement on bronchopulmonary dysplasia in extremely preterm infants

OBJECTIVE

To study whether postnatal replacement of oestradiol and progesterone may help to prevent bronchopulmonary dysplasia (BPD).

METHODS

This randomised placebo-controlled double-blind study enrolled 83 infants of <29 weeks gestational age and 1000 g birth weight requiring mechanical ventilation within 12 h after birth. Oestradiol (2.5 mg/kg/day) and progesterone (22.5 mg/kg/day) were given by continuous intravenous infusion of a standard lipid emulsion (15 ml/kg/day) in the replacement group (ESTRA-PRO). The placebo group received the same lipid emulsion without oestradiol or progesterone. A replacement period of at least 2 weeks but not >4 weeks was strived for and defined as "according to protocol". The primary outcome variable was the incidence of BPD or death.

RESULTS

The median birth weight was 670 g (min-max 400-990 g) and the gestational age 25 weeks (23.1-28.1 weeks). The incidence of BPD or death was 48% in the placebo group and 44% in the ESTRA-PRO group (p = 0.38, one-sided testing, intention to treat analysis). In infants treated according to protocol, 32% (9 of 28) in the placebo group and 14% (3 of 21) in the ESTRA-PRO group developed BPD (p = 0.08).

CONCLUSION

Replacement of oestradiol and progesterone was not effective for prevention of BPD or death in extremely preterm born infants. Better-powered trials are needed to evaluate this new approach.

Plasma KL-6 predicts the development and outcome of bronchopulmonary dysplasia

Circulating KL-6 is a specific indicator of pulmonary injury affecting the alveolar epithelium and interstitium. Our preliminary study suggested the usefulness of plasma KL-6 as a marker of bronchopulmonary dysplasia (BPD). To confirm the diagnostic value of KL-6 for BPD as well as to determine the reference range, we conducted a larger prospective study in 135 preterm infants <32 wk GA. Among the infants without oxygen dependence at a postconceptional age of 36 wk, the plasma KL-6 level showed no significant association with GA at any time. Among 42 infants <28 wk GA, plasma KL-6 levels were significantly higher in those with moderate/severe BPD compared with those with no/mild BPD. A plasma level of 199 U/mL at 1 wk or 232 U/mL at 2 wk was an excellent predictor of moderate/severe BPD <28 wk GA (positive predictive value of 83% and 80%, respectively). Unlike nonspecific markers of inflammation or fibrosis, KL-6 objectively reflects the severity of pulmonary injury irrespective of the treatment or the radiographic changes. Therefore, not only as a good marker, measurement of KL-6 may also help to provide new insights into the pathogenesis of BPD.

Elevated Carbon Dioxide Tension as a Predictor of Subsequent Adverse Events in Infants with Bronchopulmonary Dysplasia

Infants with bronchopulmonary dysplasia (BPD) are at risk for numerous complications following discharge from the Neonatal Intensive Care Unit (NICU). Few studies have evaluated risk factors for adverse events (AE). This retrospective study provided an initial evaluation of the use of capillary carbon dioxide (PCO2) tension as a predictor of infants with BPD at increased risk for AE. PCO2 was compared in patients who suffered, or avoided, severe AE, defined as pulmonary hypertension, death, or subsequent reintubation or tracheostomy for respiratory illness. One hundred twelve consecutive patients followed at the BPD clinic were evaluated, and data from 104 subjects were suitable for analysis. Mean PCO2, obtained shortly before or after discharge from NICU, was 47.2 mmHg (range, 31-83). PCO2 was significantly higher in patients who required reintubation and ventilation (54.7 vs. 46.7, p < 0.04). No cutoff value of PCO2 clearly distinguished patients with subsequent AE. PCO2 was not significantly higher in the group of patients who had a severe AE than in the group of patients who did not have a severe AE, but logistic regression showed a significant association between PCO2 and risk of both severe AE (p = 0.018), and readmission to hospital (p = 0.038). An elevated PCO2 is associated with an increased risk of AE, including reintubation, and readmission to hospital, in infants with BPD. Patients with an elevated discharge PCO2 may require closer monitoring during followup. Prospective studies will be needed to confirm these observations.

Effect of dose on response to adrenocorticotropin in extremely low birth weight infants

CONTEXT

Various cosyntropin doses are used to test adrenal function in premature infants, without consensus on appropriate dose or adequate response.

OBJECTIVE

The objective of this study was to test the cortisol response of extremely low birth weight infants to different cosyntropin doses and evaluate whether these doses differentiate between groups of infants with clinical conditions previously associated with differential response to cosyntropin.

DESIGN

The design was a prospective, nested study conducted within a randomized clinical trial of low-dose hydrocortisone from November 1, 2001, to April 30, 2003.

SETTING

The setting was nine newborn intensive care units.

PATIENTS

The patients included infants with 500-999 g birth weight.

INTERVENTION

The drug used was cosyntropin, at 1.0 or 0.1 microg/kg, given between 18 and 28 d of birth.

MAIN OUTCOME MEASURE

We measured the cortisol response to cosyntropin.

RESULTS

Two hundred seventy-six infants were tested. Previous hydrocortisone treatment did not suppress basal or stimulated cortisol values. Cosyntropin, at 1.0 vs. 0.1 microg/kg, yielded higher cortisol values (P < 0.001) and fewer negative responses (2 vs. 21%). The higher dose, but not the lower dose, showed different responses for girls vs. boys (P = 0.02), infants receiving enteral nutrition vs. not (P < 0.001), infants exposed to chorioamnionitis vs. not (P = 0.04), and those receiving mechanical ventilation vs. not (P = 0.02), as well as a positive correlation with fetal growth (P = 0.03). A response curve for the 1.0-microg/kg dose for infants receiving enteral nutrition (proxy for clinically well infants) showed a 10th percentile of 16.96 microg/dl. Infants with responses less than the 10th percentile had more bronchopulmonary dysplasia and longer length of stay.

CONCLUSIONS

A cosyntropin dose of 0.1 microg/kg did not differentiate between groups of infants with clinical conditions that affect response. We recommend 1.0 microg/kg cosyntropin to test adrenal function in these infants.

Retinol-binding protein, transthyretin, and C-reactive protein in extremely low birth weight (ELBW) infants

BACKGROUND

Vitamin A deficiency reduces retinol binding protein (RBP) but not transthyretin (TTR), while inflammation reduces both RBP and TTR and increases C-reactive protein (CRP), an acute phase reactant.

OBJECTIVE

To estimate serum RBP, TTR, and CRP in ELBW infants to test the hypotheses that (a) TTR is a negative acute phase reactant and (b) a higher RBP/TTR ratio or CRP is associated with death/BPD by 36 weeks corrected age.

DESIGN/METHODS

Serum RBP, TTR, and CRP were measured in 79 ELBW infants at 28 days. Area under the curve (AUC) of receiver operating characteristic curve analysis evaluated the predictive value of TTR, the RBP/TTR ratio, and CRP for death/BPD at 36 weeks.

RESULTS

(1) TTR inversely correlated with CRP (r=-0.45, p<0.0001) consistent with TTR being a negative acute phase reactant. (2) The RBP/TTR ratio predicted death/BPD (AUC 0.68 (CI 0.57 to 0.78)). (3) CRP strongly predicted death/BPD (AUC 0.85 (CI 0.76 to 0.92)), even after exclusion of sepsis.

CONCLUSIONS

A higher CRP and RBP/TTR molar ratio on day 28 are associated with death/BPD at 36 weeks in ELBW infants. Lower TTR and maintained RBP/TTR ratios suggest inflammation rather than vitamin A deficiency as the cause for lower serum vitamin A levels in ELBW infants..

Correlation among cytokines, bronchopulmonary dysplasia and modality of ventilation in preterm newborns: improvement with melatonin treatment

Improved survival because of advances in neonatal care has resulted in an increased number of infants at risk for chronic lung disease. Even though the etiology of lung injury is multifactorial, recent animal and clinical data indicate that pulmonary damage depends in large part on the ventilatory strategies used. Ventilator-associated lung injury was believed to result from the use of high pressure, thus, the term barotraumas. This trauma is believed to involve free-radical damage. Oxidant injury is a serious cause of lung injury. In the present study, 110 newborns with respiratory distress syndrome were studied; 55 were treated with melatonin and the other 55 with placebo. All the subjects were mechanically ventilated with or without guaranteed volume. Proinflammatory cytokines [interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)-alpha] were measured in tracheobronchial aspirate and the clinical outcome was evaluated. Melatonin treatment reduced the proinflammatory cytokines and improved the clinical outcome. The beneficial action of melatonin presumably related to its antioxidative actions.

Plasma and erythrocyte selenium and glutathione peroxidase activity in preterm infants at risk for bronchopulmonary dysplasia

The purpose of this study was to examine the relationships between selenium status, as measured by plasma and erythrocyte selenium and glutathione peroxidase (GPx) activity, and other postnatal factors, including selenium intake, gestational age, and oxygen dependence in preterm infants at risk for bronchopulmonary dysplasia. Eighteen preterm infants of 30 wk gestational age or less were included. At postnatal wk 1 and 4, selenium concentrations and GPx activity were measured and oxygen dependence and daily selenium intakes were determined from the medical chart. Plasma and erythrocyte selenium concentrations decreased from wk 1 to wk 4, whereas erythrocyte GPx activity increased. Increased selenium intakes during wk 1 were associated with increased erythrocyte GPx activity at both time-points, as well as a decreased need for supplemental oxygen on d 28. Preterm infants display increasing erythrocyte GPx activity despite declines in plasma and erythrocyte selenium. GPx activity might be enhanced by very early selenium supplementation.

Low plasma retinol concentrations increase the risk of developing bronchopulmonary dysplasia and long-term respiratory disability in very-low-birth-weight infants

BACKGROUND

The effect of inadequate vitamin A during the neonatal period on lung status is still unknown.

OBJECTIVE

We tested the hypothesis that low plasma retinol concentrations during the first month of life are independently associated with bronchopulmonary dysplasia (BPD) and long-term respiratory morbidity at 6 mo gestationally corrected age (ie, the age the infant would be had the pregnancy gone to term).

DESIGN

Respiratory outcome information was obtained to 6 mo corrected age for a historical cohort of very-low-birth-weight neonates (<1250 g) who were admitted to intensive care over a 7-y period. Neonates with one or more plasma measurements of retinol concentrations < 0.35 micromol/L (<100 microg/L) on days 1-28 were classified as having low vitamin A. BPD was defined at day 28 by clinical and radiologic criteria and by use of supplemental oxygen at 36 wk postmenstrual age (PMA). Dependence on supplemental oxygen was used to identify long-term respiratory disability at 6 mo corrected age. Multivariate logistic regression analyses were conducted.

RESULTS

Of the 350 study infants, 192 (55%) had low vitamin A status. BPD occurred in 52% of survivors at day 28 (173/331) and at 36 wk PMA (147/285). Fourteen percent (33/244) required oxygen support at 6 mo corrected age. Adjusted odds ratios of BPD with low vitamin A were 3.5 (95% CI: 1.7, 7.2) at day 28 and 1.7 (1.0, 2.7) at 36 wk PMA. At 6 mo corrected age, the adjusted odds ratio was 2.6 (1.1, 6.4) for respiratory disability with low vitamin A.

CONCLUSION

Poor vitamin A status during the first month of life significantly increased the risk of developing BPD and long-term respiratory disability.

Successful treatment of acute respiratory distress syndrome and severe pulmonary hypertension in a child with Bordetella pertussis infection

Infection with Bordetella pertussis can cause severe illness with neurological and pulmonary complications in children. Pulmonary hypertension is an early sign of potentially fatal disease and can cause failure of conventional respiratory therapy in severe acute respiratory distress syndrome (ARDS). We report a 4 1/2-year-old boy with B. pertussis infection who developed severe ARDS and pulmonary hypertension. Because of severe neurological signs the patient did not qualify for extracorporal membrane oxygenation (ECMO). After conventional ventilation, surfactant and high frequency oscillation ventilation (HFOV) failed, treatment with nitric oxide (NO) improved oxygenation, allowing recovery without the need for ECMO. The patient survived with few sequelae. Thus, this treatment may be an option in high-risk children who meet the criteria for ECMO but are excluded because of poor neurological status, as in our patient.

Vitamin A and Bronchopulmonary Dysplasia: Research, Issues, and Clinical Practice

Vitamin A is a crucial antioxidant for preterm infants because it protects the lungs from oxidative damage induced by the administration of supplemental oxygen. Although all preterm infants are born with smaller vitamin A stores than full-term infants, the store of vitamin A in preterm infants at risk for bronchopulmonary dysplasia (BPD) is often especially deficient. Despite the increases in plasma vitamin A concentrations that have been achieved with vitamin A supplementation, only modest improvements in clinical outcomes and incidence of BPD have been noted in this population. This article reviews the research on vitamin A supplementation for preterm infants, as well as the issues and clinical implications associated with this intervention.

Coagulase-negative staphylococcal sepsis as a predictor of bronchopulmonary dysplasia

AIM

To determine whether sepsis caused by coagulase-negative staphylococci (CoNS) is a risk factor for developing bronchopulmonary dysplasia (BPD) in premature newborns.

METHODS

All newborns born at < or = 30 wk of gestation at Orebro University Hospital during 1994-2001 with clinical sepsis caused by CoNS (group A, n = 22) or by other bacteria (group B, n = 17) were included and compared with premature newborns without sepsis (group C, n = 53). Clinical sepsis was defined as a positive blood culture (monoculture) plus clinical symptoms and laboratory findings. BPD was defined as treatment with oxygen > 21% for at least 28 d.

RESULTS

The incidence of BPD differed between the three groups, as follows: CoNS sepsis (A) 64%, other sepsis (B) 41% and control (C) 24%. The difference between the control group and the sepsis groups was highly significant (p = 0.006). In a univariate model the crude estimates of relative risk (RR) for occurrence of BPD increased with presence of sepsis and particularly with presence of sepsis with CoNS (A: RR 2.6, 95% CI 1.5-4.6, p = 0.001; B: RR 1.7, CI 0.8-3.5, p = 0.17). When regression was performed with two additional predictive variables in multivariate models including sepsis, gestational age and mechanical ventilation (group A: RR 1.5, CI 1.1-2.0, p = 0.004; group B: RR 0.9, CI 0.6-1.4, p = 0.67), the estimates were lower.

CONCLUSION

The relative risk for BPD is significantly increased in premature newborns with sepsis caused by CoNS compared with those with sepsis caused by other bacteria and compared with premature newborns with no sepsis.

Inflammatory markers in intrauterine and fetal blood and cerebrospinal fluid compartments are associated with adverse pulmonary and neurologic outcomes in preterm infants

Recent evidence strongly implicates the inflammatory response to intrauterine infection in the pathogenesis of neonatal brain and lung injury. We hypothesized that lung and brain injury in preterm infants occurs during a common developmental window of vulnerability as the result of an inflammatory response in different compartments. To determine whether inflammatory markers in these compartments are associated with bronchopulmonary dysplasia (BPD) or cranial ultrasound (CUS) abnormalities in infants <33 wk gestation age (GA) and <1501 g birth weight, we analyzed placental pathology and serum and cerebrospinal fluid (CSF) IL-6, IL-1beta, and tumor necrosis factor-alpha (TNF-alpha) concentrations in 276 infants. Logistic regressions were performed stratified by GA. Histologic chorioamnionitis was significantly associated with BPD in infants </=28 wk GA (OR 3.6, p = 0.027). Maternal stage of chorioamnionitis significantly correlated with severity of BPD. Presence of a fetal inflammatory response indicated by fetal vasculitis or elevated cytokines was not associated with the development of BPD. Serum IL-6 >/=17 pg/mL was associated with an abnormal CUS in infants >28 wk GA (OR 3.36, p = 0.023) but not </=28 wk GA. CSF concentrations of IL-6 >/=6.5 pg/mL and TNF-alpha >/=3 pg/mL were associated with abnormal CUS in infants </=28 wk GA (IL-6 OR 3.0; TNF-alpha OR 3.5; p < 0.05 each case) but not >/=28 wk GA. These data suggest that in infants </=28 wks GA, BPD may be initiated by inflammatory mediators in amniotic fluid, but brain injury may involve variations in the systemic inflammatory response.

MMP-2 and MMP-9 and their tissue inhibitors in the plasma of preterm and term neonates

Matrix metalloproteinases (MMP) and their tissue inhibitors (TIMP) are involved in a variety of physiologic growth and development and pathophysiologic inflammatory conditions. We hypothesized that 1) MMP-2 and -9 plasma activities and TIMP-1 and -2 plasma concentrations in preterm and term neonates were dependent on the gestational and postnatal age; and 2) the respective MMP and their inhibitors were deranged in the development of bronchopulmonary dysplasia (BPD) and intraventricular hemorrhage (IVH) in preterm neonates. From 1998 to 1999, blood samples were collected from preterm neonates (25-36 wk gestation) with or without BPD and/or IVH as well as from healthy term (37-40 wk gestation) neonates during the first 28 d of life. MMP-2 and MMP-9 plasma activities were measured by zymography; TIMP-1 and TIMP-2 plasma concentrations were determined by ELISA. In neonates without BPD or IVH (n = 50), MMP-2 and MMP-9 plasma activities both appeared to be gestational age dependent, with the highest levels observed in neonates of 33-36 wk gestation. TIMP-1 plasma concentration was highest in term neonates but no gestational difference was found in TIMP-2. Only MMP-9 showed a 50% decrease after d 1 in the first postnatal month. Twelve preterm infants with BPD and/or IVH had significantly lower MMP-2 but higher MMP-9 activity and higher TIMP-1 concentration than those of corresponding neonates without BPD or IVH. These findings show the gestational age-dependent expression of plasma MMP activities and their inhibitors. MMP and TIMP may be involved in the feto-neonatal development and may contribute to the pathogenesis of BPD and/or IVH in critically ill preterm neonates.