Epithelial lining fluid free IGF-I-to-PAPP-A ratio is associated with bronchopulmonary dysplasia in preterm infants

Can first trimester pregnancy-associated plasma protein-A predict the surfactant needs of preterm neonates?

BACKGROUND

Low values of pregnancy associated plasma protein A (PAPP-A), have been shown to be associated with some poor gestational outcomes, especially those related to placental deficiency such as pre-eclampsia and fetal growth restriction as well as preterm labor. The aim of this study was to compare first trimester PAPP-A MoM values with the surfactant needs of newborns of pregnant women who had a preterm delivery.

METHODS

This study included 216 pregnant women who had a preterm delivery, who were found to be in the low-risk group based on their aneuploidy screening. The women were separated into two groups based on the surfactant receipts of their newborns. A record was made of the obstetric history, birth characteristics of the preterm infants, and whether or not there was a need for surfactant.

RESULTS

A comparison of the PAPP-A values of the two groups revealed that the group that received surfactant had statistically significantly lower PAPP-A values (t(-3.97) = 0.203, p <  0.001). When the cut-off value of PAPP-A was taken as 1 MoM and the gestational age was analyzed together with the birth weight, PAPP-A alone was found to be a significant independent variable for the prediction of respiratory distress syndrome (RDS) (p = 0.031; OR:8.2 (1.2-55.6)).

CONCLUSIONS

The result of this study demonstrated that PAPP-A MoM values may be significant in predicting the need for surfactant in RDS, which is a frequently seen condition in the neonatal period.

Development of a Sensitive High-Resolution Mass Spectrometry Approach for Urea Nitrogen Quantitation in Small Volumes of Bronchoalveolar Lavage Fluid (BALF)

A sensitive, selective, and quantitative method incorporating high-resolution mass spectrometry was developed for the determination of blood urea nitrogen (BUN) in bronchoalveolar lavage fluid. The method requires no sample cleanup or derivatization prior to analysis. High-performance liquid chromatography (HPLC) on a Hypersil Gold PFP column (100 × 3 mm, 3 μm particle size) connected to a C18 guard column was employed for a 10 min chromatographic separation. The detection of urea was achieved using a Thermo Scientific Q-Exactive Plus instrument incorporating selected ion monitoring (SIM) modes for the protonated adduct of urea. The urea analytical measuring range for the method is 0.047-17.134 mg/dL, resulting in a BUN analytical measurement range of 0.022-8.007 mg/dL, which allows for quantitation over 3 orders of magnitude (R² = 0.999). In addition, the method is suitable for small sample volumes (15 μL) with a high level of accuracy, precision, and specificity.

The utility of pregnancy associated plasma protein-A MoM values in prediction of term respiratory distress syndrome

This study aimed to investigate if the pregnancy associated plasma Protein-A (PAPP-A) multiples of median (MoM) levels could be used as a marker for the early prediction of RDS. The present study was designed with data gathered from 1773 patients who were referred to our institution for first trimester fetal chromosomal anomaly screening. First trimester PAPP-A MoM values and postnatal RDS occurrences in these pregnancies were retrospectively analysed. Of the 1773 neonates that were included in the study, 28 were delivered at or beyond 37 weeks, and 42 were delivered less than 37 weeks of gestation. In the group of neonates at or beyond 37 weeks, the cut-off value for RDS prediction was determined as 1.02. For this cut-off value, sensitivity was 72.41% and specificity was 91.84%. The area under curve (AUC) was determined to be statistically significant (p < .01). In conclusion, it was determined that in neonates that were delivered at or beyond 37 weeks of gestation, RDS occurrence could be predicted at a significant rate by utilising PAPP-A MoM values.IMPACT STATEMENTWhat is already known on this subject? Respiratory distress syndrome (RDS) is one of the major global healthcare problems, and continues to effect newborns despite the improvements in diagnosis and treatments of the disease. Studies have shown that pregnancy associated plasma protein-A (PAPP-A) has a critical role in cellular proliferation and differentiation, and it is closely associated with many physiological and pathological processes via regulation of local insulin like growth factor (IGF) concentrations. In majority of the past studies in the literature regarding PAPP-A values in pregnancies, the association between low values of PAPP-A MoM and maternal-fetal complications were investigated.What do the results of this study add? This study retrospectively examines the PAPP-A MoM levels and the occurence of RDS. In neonates that were delivered at or beyond 37 weeks of gestation, RDS occurrence could be predicted at a significant rate by utilising PAPP-A MoM values which was measured at the first trimester fetal anomaly screening test.What are the implications of these findings for clinical practice and/or further research? In the light of these findings, in order to reduce RDS related neonatal morbidity and mortality, pregnancies with PAPP-A MoM values greater than 1.02 at the first trimester fetal anomaly screening should be more closely followed up and a higher rate of suspicion should be kept for RDS occurrence.

Insulin-Like Growth Factor-1 Signaling in Lung Development and Inflammatory Lung Diseases

Insulin-like growth factor-1 (IGF-1) was firstly identified as a hormone that mediates the biological effects of growth hormone. Accumulating data have indicated the role of IGF-1 signaling pathway in lung development and diseases such as congenital disorders, cancers, inflammation, and fibrosis. IGF-1 signaling modulates the development and differentiation of many types of lung cells, including airway basal cells, club cells, alveolar epithelial cells, and fibroblasts. IGF-1 signaling deficiency results in alveolar hyperplasia in humans and disrupted lung architecture in animal models. The components of IGF-1 signaling pathways are potentiated as biomarkers as they are dysregulated locally or systemically in lung diseases, whereas data may be inconsistent or even paradoxical among different studies. The usage of IGF-1-based therapeutic agents urges for more researches in developmental disorders and inflammatory lung diseases, as the majority of current data are collected from limited number of animal experiments and are generally less exuberant than those in lung cancer. Elucidation of these questions by further bench-to-bedside researches may provide us with rational clinical diagnostic approaches and agents concerning IGF-1 signaling in lung diseases.

A Pathogenic Relationship of Bronchopulmonary Dysplasia and Retinopathy of Prematurity? A Review of Angiogenic Mediators in Both Diseases

Bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP) are common and significant morbidities of prematurely born infants. These diseases have in common altered and pathologic vascular formation in the face of incomplete organ development. Therefore, it is reasonable to question whether factors affecting angiogenesis could have a joint pathogenic role for both diseases. Inhibition or induced expression of a single angiogenic factor is unlikely to be 100% causative or protective of either of BPD or ROP. It is more likely that interactions of multiple factors leading to disordered angiogenesis are present, increasing the likelihood of common pathways in both diseases. This review explores this possibility by assessing the evidence showing involvement of specific angiogenic factors in the vascular development and maldevelopment in each disease. Theoretical interactions of specific factors mutually contributing to BPD and ROP are proposed and, where possible, a timeline of the proposed relationships between BPD and ROP is developed. It is hoped that future research will be inspired by the theories put forth in this review to enhance the understanding of the pathogenesis in both diseases.

A risk factor analysis on disease severity in 47 premature infants with bronchopulmonary dysplasia

Bronchopulmonary Dysplasia (BPD) is a rare chronic lung disease and one of the most difficult complications to treat in premature infants. With the progress at the medical treatment level, an increasing number of BPD premature infants are born, meanwhile, they would be at an increasing risk for numerous complications and rehospitalization because BPD affects many vital organ systems. The pathogenesis of BPD is clearly multifactorial. As the prognosis is closely connected with the severity of BPD, early diagnosis and treatment are of great help to control the development of BPD. This article focuses on risk factors that could influence the severity of BPD in order to provide a reliable basis for early diagnosis, treatment, and better patient assessment.

Description of an Automated Method for Urea Nitrogen Determination in Bronchoalveolar Lavage Fluid (BALF) of Neonates and Infants

Bronchoalveolar lavage (BAL) partially recovers both the instilled saline and the alveolar fluid, so-called epithelial lining fluid (ELF), but a correction for the dilution due to the BAL technique itself is needed to know the amount of recovered ELF. In this regard, urea nitrogen may be useful and has been proposed to calculate ELF. The aim of the present study was to develop and validate a new method to measure urea nitrogen in BAL fluid (BALF). We used 19 BALF samples obtained from neonates and infants with different respiratory conditions. The urea nitrogen assay was carried out on Cobas c311 analyzer (Roche Diagnostics). A validation study shows that the method is perfectly linear (R(2) = 0.999), sensitive (limit of detection = 0.055 mg/dL; limit of quantification = 0.16 mg/dL), repeatable (low = 0.15 ± 0.02, 13.3%; high = 1.80 ± 0.02, 1.1%), reproducible (low = 0.14 ± 0.02, 14.2 %; high = 1.76 ± 0.04, 2.2 %) with accuracy ranging between 93-96%. Our results support the robustness of validated procedure since the described method appears simple, precise, rapid, and suitable for routine analysis. Thus, it may be used to correct concentration of various noncellular BAL components and calculate their ELF amounts in neonates and infants.

Clinical and biological role of secretory phospholipase A2 in acute respiratory distress syndrome infants

INTRODUCTION

Secretory phospholipase A2 is supposed to play a role in acute lung injury but no data are available for pediatric acute respiratory distress syndrome (ARDS). It is not clear which enzyme subtypes are secreted and what the relationships are between enzyme activity, biophysical and biochemical parameters, and clinical outcomes. We aimed to measure the enzyme and identify its subtypes and to study its biochemical and biophysical effect. The secondary aim was to correlate enzyme activity with clinical outcome.

METHODS

Bronchoalveolar lavage was performed in 24 infants with ARDS and 14 controls with no lung disease. Samples were assayed for secretory phospholipase A2 and molecules related to its activity and expression. Western blotting and captive bubble surfactometry were also performed. Clinical data were real time downloaded.

RESULTS

Tumor necrosis factor-α (814 (506-2,499) vs. 287 (111-1,315) pg/mL; P = 0.04), enzyme activity (430 (253-600) vs. 149 (61-387) IU/mL; P = 0.01), free fatty acids (4.3 (2.8-8.6) vs. 2 (0.8-4.6) mM; P = 0.026), and minimum surface tension (25.6 ± 6.1 vs. 18 ± 1.8 mN/m; P = 0.006) were higher in ARDS than in controls. Phospholipids are lower in ARDS than in controls (76.5 (54-100) vs. 1,094 (536-2,907) μg/mL; P = 0.0001). Three enzyme subtypes were identified (-IIA, -V, -X), although in lower quantities in controls; another subtype (-IB) was mainly detected in ARDS. Significant correlations exist between enzyme activity, free fatty acids (ρ = 0.823; P < 0.001), and surface tension (ρ = 0.55; P < 0.028). Correlations also exist with intensive care stay (ρ = 0.54; P = 0.001), PRISM-III24 (ρ = 0.79; P< 0.001), duration of ventilation (ρ = 0.53; P = 0.002), and oxygen therapy (ρ = 0.54; P = 0.001).

CONCLUSIONS

Secretory phospholipase A2 activity is raised in pediatric ARDS and constituted of four subtypes. Enzyme correlates with some inflammatory mediators, surface tension, and major clinical outcomes. Secretory phospholipase A2 may be a clinically relevant target in pediatric ARDS.

The IGF-I/IGF-R1 pathway regulates postnatal lung growth and is a nonspecific regulator of alveologenesis in the neonatal rat

IGF-I, IGF-II, and the IGF-I receptor are widely distributed throughout the neonatal rat lung on days 4, 7, 10, and 14 of life, with a similar abundance at each of these time points. Injection of 20 μg/g of a truncated soluble IGF-I receptor on days 2 and 5 of life, to decoy ligand away from the endogenous IGF-I receptor, reduced lung weight and lung-to-body weight ratio, reduced lung tissue fraction, and impaired alveolar formation, as assessed by secondary crest formation and mean linear intercepts on day 7 of life. Lung procollagen I content and elastin fiber density were also reduced. Injection of 100 μg/day of neutralizing anti-IGF-I, to prevent IGF-I from binding to the IGF-I receptor, on days 3, 4, and 5 of life reduced tissue fraction and elastin fiber density and impaired alveolar formation on day 6 of life. Both interventions reduced total lung cell and secondary crest cell DNA synthesis and small vessel counts per unit area, but these effects were lost after normalization to the reduced tissue fraction. These findings are consistent with a role for IGF-I binding to the IGF-I receptor in postnatal lung growth and on alveologenesis through a nonspecific positive effect on DNA synthesis. Injection of 100 μg/day of neutralizing anti-IGF-II, to prevent IGF-II from binding to the IGF-I receptor, on days 3, 4, and 5 of life had no effect on total lung cell DNA synthesis per unit area on day 6 of life, and a role for IGF-II in postnatal alveologenesis was not further pursued.

Low postnatal serum IGF-I levels are associated with bronchopulmonary dysplasia (BPD)

Aim:

To characterize postnatal changes in serum insulin-like growth factor-1 (IGF-I) in relation to development of bronchopulmonary dysplasia (BPD) in very preterm infants.

Methods:

Longitudinal study of 108 infants with mean (SD) gestational age (GA) 27.2 (2.2) weeks. Weekly serum samples of IGF-I were analysed from birth until postmenstrual age (PMA) 36 weeks. Multivariate models were developed to identify independent predictors of BPD.

Results:

Postnatal mean IGF-I levels at postnatal day (PND) 3–21 were lower in infants with BPD compared with infants with no BPD (16 vs. 26 μg/L, p < 0.001). Longitudinal postnatal change in IGF-I levels (IGF-I regression coefficient (β)), PNDs 3–21, was lower in infants with BPD compared with infants with no BPD (0.28 vs. 0.97, p = 0.002) and mean IGF-I during PMA 30–33 weeks was lower in infants with BPD as compared with infants without BPD (22 vs. 29 μg/L, p < 0.001). In a binomial multiple regression model, lower GA, male gender and lower mean serum IGF-I levels during PND 3–21 were the most predictive risk factors associated with BPD (r² = 0.634, p < 0.001).

Conclusion:

Lower IGF-I concentrations during the first weeks after very preterm birth are associated with later development of BPD.

Ex vivo effect of varespladib on secretory phospholipase A2 alveolar activity in infants with ARDS

Background

Secretory phospholipase A2 (sPLA2) plays a pivotal role in acute respiratory distress syndrome (ARDS). This enzyme seems an interesting target to reduce surfactant catabolism and lung tissue inflammation. Varespladib is a specifically designed indolic sPLA2 inhibitor, which has shown promising results in animals and adults. No specific data in pediatric ARDS patients are yet available.

Methods

We studied varespladib in broncho-alveolar lavage (BAL) fluids obtained ex vivo from pediatric ARDS patients. Clinical data and worst gas exchange values during the ARDS course were recorded. Samples were treated with saline or 10–40–100 µM varespladib and incubated at 37°C. Total sPLA2 activity was measured by non-radioactive method. BAL samples were subjected to western blotting to identify the main sPLA isotypes with different sensitivity to varespladib. Results was corrected for lavage dilution using the serum-to-BAL urea ratio and for varespladib absorbance.

Results

Varespladib reduces sPLA2 activity (p<0.0001) at 10,40 and 100 µM; both sPLA2 activity reduction and its ratio to total proteins significantly raise with increasing varespladib concentrations (p<0.001). IC₅₀ was 80 µM. Western blotting revealed the presence of sPLA2-IIA and –IB isotypes in BAL samples. Significant correlations exist between the sPLA2 activity reduction/proteins ratio and PaO₂ (rho = 0.63;p<0.001), PaO₂/FiO₂ (rho = 0.7; p<0.001), oxygenation (rho = −0.6; p<0.001) and ventilation (rho = −0.4;p = 0.038) indexes.

Conclusions

Varespladib significantly inhibits sPLA2 in BAL of infants affected by post-neonatal ARDS. Inhibition seems to be inversely related to the severity of gas exchange impairment.

Secretory phospholipase A2 pathway in various types of lung injury in neonates and infants: a multicentre translational study

BACKGROUND

Secretory phospholipase A2 (sPLA2) is a group of enzymes involved in lung tissue inflammation and surfactant catabolism. sPLA2 plays a role in adults affected by acute lung injury and seems a promising therapeutic target. Preliminary data allow foreseeing the importance of such enzyme in some critical respiratory diseases in neonates and infants, as well. Our study aim is to clarify the role of sPLA2 and its modulators in the pathogenesis and clinical severity of hyaline membrane disease, infection related respiratory failure, meconium aspiration syndrome and acute respiratory distress syndrome. sPLA2 genes will also be sequenced and possible genetic involvement will be analysed.

METHODS/DESIGN

Multicentre, international, translational study, including several paediatric and neonatal intensive care units and one coordinating laboratory. Babies affected by the above mentioned conditions will be enrolled: broncho-alveolar lavage fluid, serum and whole blood will be obtained at definite time-points during the disease course. Several clinical, respiratory and outcome data will be recorded. Laboratory researchers who perform the bench part of the study will be blinded to the clinical data.

DISCUSSION

This study, thanks to its multicenter design, will clarify the role(s) of sPLA2 and its pathway in these diseases: sPLA2 might be the crossroad between inflammation and surfactant dysfunction. This may represent a crucial target for new anti-inflammatory therapies but also a novel approach to protect surfactant or spare it, improving alveolar stability, lung mechanics and gas exchange.

Secretory phospholipase A₂ pathway during pediatric acute respiratory distress syndrome: a preliminary study

OBJECTIVE

To verify if secretory phospholipase A2 (sPLA2) is increased in pediatric acute respiratory distress syndrome (ARDS) triggered or not by respiratory syncytial virus infection and to clarify how the enzyme may influence the disease severity and the degree of ventilatory support.

DESIGN

Prospective pilot study.

SETTING

Two academic pediatric intensive care units.

PATIENTS

All infants < 6 months old hospitalized for severe respiratory syncytial virus bronchiolitis, who developed ARDS (respiratory syncytial virus-ARDS group); all infants < 6 months old diagnosed with ARDS secondary to other causes (ARDS group); and infants < 6 months old who needed ventilation for reasons other than any lung disease (control group).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We enrolled six respiratory syncytial virus -ARDS babies, five ARDS babies, and six control infants. The sPLA2 activity and tumor necrosis factor (TNF)-α were significantly higher in the bronchoalveolar lavage of ARDS infants. Worst oxygenation, ventilation, and longer pediatric intensive care unit stay and ventilation time were present in ARDS babies. No differences were found in Clara cell secretory protein and in serum cytokines levels. Because there is no correlation between bronchoalveolar lavage protein content (a marker of permeability) and sPLA2, the enzyme seems mainly produced in the alveoli. TNF-α, the main inductor of sPLA2 expression, significantly correlates with the enzyme level in the bronchoalveolar lavage. Significant positive correlations exist between sPLA2, TNF-α and oxygen need, mean airway pressure, ventilatory index, and the Murray's lung injury score. Negative correlations were also found between sPLA2, TNF-α, and Pao2/Fio2 ratio.

CONCLUSIONS

The sPLA2 and TNF-α are increased in ARDS and seem correlated with clinical severity, higher oxygen requirement, and more aggressive ventilation. This correlation confirms findings from adult experience and should guide further investigations on pediatric ARDS pathophysiology.

Insulin-like growth factor I (CA) repeats are associated with higher melanoma's Breslow index but not associated with the presence of the melanoma. A pilot study

BACKGROUND

IGF-I-(CA) repeats have been previously analysed in few types of cancer and the results, although discordant in different studies, showed possible associations between cancer and IGF-I(CA)(19) repeats. Aim of this pilot study was to detect a possible association between some of the IGF-I(CA) repeats and the presence of malignant melanoma and its Breslow index.

METHODS

Two hundred patients affected with cutaneous malignant melanoma and 100 control healthy subjects were analysed for IGF-I(CA) repeats by fragment analysis sequencing and, partially, confirmed by direct sequencing.

RESULTS

A significant association of IGF-I(CA)(19) repeats was observed with melanoma higher Breslow indices (P<0.001), while no association between melanoma patients and the different genotypes of IGF-I(CA) was found. The above mentioned association was confirmed after Bonferroni's correction for multiple comparisons and also by logistic regression analysis adjusted for age, sex and BMI variables. A slight, significant difference (P=0.03) was observed for serum IGF-I values in IGF-I(CA)(19)-positive or IGF-I(CA)(19)-negative subjects.

DISCUSSION

The association observed for IGF-I(CA)(19) and malignant melanoma is in keeping with similar results obtained in prostate or breast cancers, suggesting that this type of repeat may be directly or indirectly important in controlling cancer induction and its severity.

Mannose-binding lectin polymorphisms and pulmonary outcome in premature neonates: a pilot study

OBJECTIVE

Mannose-binding lectin (MBL2) is a collectin molecule able to activate the complement system and the subsequent inflammatory mechanisms. Several MBL2 genetic variants have been described, including the six variants studied in this report, which are those analyzed in most detail in the medical literature.

DESIGN

The present study analyzes the prevalence of MBL2 gene variants in preterm newborns and associates individual genotypes with pulmonary outcome variables. All polymorphisms were analyzed by means of a commercially available reverse dot-blot kit.

SETTING

Tertiary neonatal intensive care unit.

PATIENTS AND PARTICIPANTS

Seventy-five consecutive preterm newborns.

MEASUREMENTS AND RESULTS

Two variants were particularly analyzed: -550G > C and R52C. The first one is known to be associated with lower protein synthesis when included in specific haplotypes. The homozygous and heterozygous -550G > C mutations were significantly associated with protective effects regarding different lung outcome variables, including shorter duration of mechanical ventilation, hours of continuous positive airway pressure and lower number of hemotransfusions. In contrast, the heterozygous R52C mutation was associated with unfavorable outcome, including higher bronchopulmonary dysplasia prevalence. Multivariate logistic regression analysis showed that these associations were independent of gestational age and birth weight. In addition, four groups of patients were defined on the basis of haplotype combinations. Those known to be associated with low serum MBL2 levels were linked to a better outcome in terms of factors such as hours of mechanical ventilation, continuous positive airway pressure, number of hemotransfusions and bronchopulmonary disease development.

CONCLUSIONS

The four haplotype combination groups may have a potential diagnostic use as opposite risk factors for lung disease of prematurity.

Sinus mucocele secondary to craniofacial trauma in a dog

A sinsus mucocele formed in the frontal sinus of a dog secondary to obstruction of the nasofrontal opening. The dog was successfully treated by surgical enlargement of the nasofrontal opening, curettage of the sinus epithelium, and placement of a fat graft and drain in the sinus. Although mucocele formation is uncommon in animals, it should be considered as a differential diagnosis for masses of the sinonasal area. Characteristic radiographic and cytologic findings should alert the clinician to this diagnosis, and along with aggressive treatment, should shorten the diagnostic and treatment delay experienced by the dog in this report.