Przemko Kwinta

Preterm birth and respiratory disease in later life

Chronic respiratory diseases are a common complication of preterm birth, particularly among very immature infants or those suffering from bronchopulmonary dysplasia. Major progress in the treatment of preterm newborns has changed the pattern of late respiratory complications. The major respiratory problem in infancy and early childhood is respiratory exacerbations caused by infections (particularly viral ones), which need hospitalization. The symptoms become mild in school-age children; however, a group of children still present with chronic airway obstruction defined by recurrent episodes of wheezing and decreased lung function tests (decreased forced expiratory volume). For some preterm infants, particularly those with bronchopulmonary dysplasia, obstructive lung disease persists into adulthood. They are very likely to develop chronic obstructive pulmonary disease or similar disease later in life. In these patients, a program of lung function monitoring and pulmonary prophylaxis by means of elimination of specific risk factors in adulthood is advisable.

Genetic risk factors of bronchopulmonary dysplasia.

The aim of the study was to assess the association between bronchopulmonary dysplasia (BPD) and polymorphisms of genes coding for vascular endothelial growth factor (VEGF), transforming growth factor (TGF-β1), insulin-like growth factor (IGF-1), and 5,10-methylenetetrahydrofolate reductase (MTHFR). A sample of 181 newborns with mean gestational age of 28 wk was prospectively evaluated. Molecular analysis of TGF-β1 −800G>A, −509C>T, 10T>C, 25G>C, VEGF −460T>C and 405G>C and MTHFR 677C>T polymorphisms were performed and the number of CA repeats in the promoter region of IGF-1 gene was assessed. The frequency of all TGF-β1, IGF-1, and MTHFR polymorphisms, as well as the frequency of VEGF 405G>C polymorphism was similar in all groups. The newborns with −460TT and −460CT genotypes were significantly overrepresented in the BPD groups compared with the no BPD group. Multivariate analysis revealed that carrying T allele increased the risk of BPD by 9% (95%CI: 2–14%) above the baseline risk established for given gestational age, length of oxygen therapy, and sex. Based on our data from a single center, we propose that VEGF −460T>C polymorphism may influence the risk of BPD.

Gene Expression Profiling in Preterm Infants: New Aspects of Bronchopulmonary Dysplasia Development

Rationale Bronchopulmonary dysplasia is one of the most serious complications observed in premature infants. Thanks to microarray technique, expression of nearly all human genes can be reliably evaluated. Objective To compare whole genome expression in the first month of life in groups of infants with and without bronchopulmonary dysplasia. Methods 111 newborns were included in the study. The mean birth weight was 1029g (SD:290), and the mean gestational age was 27.8 weeks (SD:2.5). Blood samples were drawn from the study participants on the 5th, 14th and 28th day of life. The mRNA samples were evaluated for gene expression with the use of GeneChip® Human Gene 1.0 ST microarrays. The infants were divided into two groups: bronchopulmonary dysplasia (n=68) and control (n=43). Results Overall 2086 genes were differentially expressed on the day 5, only 324 on the day 14 and 3498 on the day 28. Based on pathway enrichment analysis we found that the cell cycle pathway was up-regulated in the bronchopulmonary dysplasia group. The activation of this pathway does not seem to be related with the maturity of the infant. Four pathways related to inflammatory response were continuously on the 5th, 14th and 28th day of life down-regulated in the bronchopulmonary dysplasia group. However, the expression of genes depended on both factors: immaturity and disease severity. The most significantly down-regulated pathway was the T cell receptor signaling pathway. Conclusion The results of the whole genome expression study revealed alteration of the expression of nearly 10% of the genome in bronchopulmonary dysplasia patients.

Can Early Echocardiographic Findings Predict Patent Ductus Arteriosus

Background: Prophylactic treatment with prostaglandin synthetase inhibitors (PSI) is potentially harmful. Moreover, long-term benefits of prophylactic use of indomethacin or ibuprofen are not proven. Early treatment of a high-risk population is alternative to the routine prophylactic use of PSI, but it remains unclear which newborn is at greatest risk for patent ductus arteriosus (PDA). Objective: Evaluation of the prognostic value of early echocardiographic studies with respect to PDA in later life. Methods: Sixty preterm infants with a mean birth weight of 1,087 g and mean gestational age of 28.5 weeks were included in a prospective study. Cardiac scans were performed in all newborns on entry into the study (within 12–48 h after birth) and further in case of clinical suspicion of PDA or obligatorily on the 7th and 28th days of life. There was no prophylactic or treatment use of any PSI during the study period. Newborns were divided into 2 cohorts: with significant left to right shunt requiring surgical ligation of PDA (n = 16) or without significant PDA during follow-up (control group, n = 44). Results: On entry, the mean internal diameter of the ductus arteriosus (2.6 vs. 0.91 mm/kg; p < 0.01), mean cardiac index across aortic valve (2.96 vs. 2.37 l/min/m2; p < 0.01) and early filling peak velocity (43.1 vs. 33.7; p = 0.01) were significantly higher in babies who later needed surgical ligation of PDA. There was no difference in the mean values of the other echocardiographic parameters studied. An early ductal diameter of >1.5 mm/kg predicted symptomatic PDA with a sensitivity of 94% and a specificity of 73%, and its positive predictive value equaled 57% and negative predictive value amounted to 97%. Conclusions: Early echocardiographic studies possess negative predictive value and may decrease unnecessary surgical ligation of PDA in very low birth weight infants.

Additional genetic risk factor for death in children with acute lymphoblastic leukemia: A common polymorphism of the MTHFR gene

The presence of metabolically important genetic polymorphisms may affect treatment efficacy in patients with malignancies. The objective of this prospective multicenter study was to evaluate the role of selected polymorphisms of genes associated with metabolism of chemotherapeutic drugs as prognostic markers in children with acute lymphoblastic leukemia.

Transcriptome profiling of the newborn mouse brain after hypoxia-reoxygenation: hyperoxic reoxygenation induces inflammatory and energy failure responsive genes

Background:Supplemental oxygen used during resuscitation can be detrimental to the newborn brain. The aim was to determine how different oxygen therapies affect gene transcription in a hypoxia–reoxygenation model.Methods:C57BL/6 mice (n = 56), postnatal day 7, were randomized either to 120 min of hypoxia 8% O2 followed by 30 min of reoxygenation with 21, 40, 60, or 100% O2, or to normoxia followed by 30 min of 21 or 100% O2. Affymetrix 750k expression array was applied with RT-PCR used for validation. Histopathology and immunohistochemistry 3 d after hypoxia–reoxygenation compared groups reoxygenated with 21 or 100% O2 with normoxic controls (n = 22).Results:In total, ~81% of the gene expression changes were altered in response to reoxygenation with 60 or 100% O2 and constituted many inflammatory-responsive genes (i.e., C5ar2, Stat3, and Ccl12). Oxidative phosphorylation was downregulated after 60 or 100% O2. Iba1+ cells were significantly increased in the striatum and hippocampal CA1 after both 21 and 100% O2.Conclusion:In the present model, hypoxia–reoxygenation induces microglial accumulation in subregions of the brain. The transcriptional changes dominating after applying hyperoxic reoxygenation regimes include upregulating genes related to inflammatory responses and suppressing the oxidative phosphorylation pathway.

Transcriptome profiling of the newborn mouse lung after hypoxia and reoxygenation: hyperoxic reoxygenation affects mTOR signaling pathway, DNA repair, and JNK-pathway regulation

Background:The use of oxygen in acute treatment of asphyxiated term newborns is associated with increased mortality. It is unclear how hyperoxic reoxygenation after hypoxia affects transcriptional changes in the newborn lung.Methods:On postnatal day 7, C57BL/6 mice (n = 62) were randomized to 120-min hypoxia (fraction of inspired oxygen (FiO2) 0.08) or normoxia. The hypoxia group was further randomized to reoxygenation for 30 min with FiO2 0.21, 0.40, 0.60, or 1.00, and the normoxia group to FiO2 0.21 or 1.00. Transcriptome profiling was performed on homogenized lung tissue using the Affymetrix 750k expression array, and validation was carried out by real-time polymerase chain reaction and enzyme-linked immunosorbent assay.Results:The hypoxia–reoxygenation model induced hypoxia-inducible factor 1 (HIF-1) targets like Vegfc, Adm, and Aqp1. In total, ~70% of the significantly differentially expressed genes were detected in the two high hyperoxic groups (FiO2 0.60 and 1.00). Reoxygenation with 100% oxygen after hypoxia uniquely upregulated Gadd45g, Dusp1, Peg3, and Tgm2. Pathway analysis identified mammalian target of rapamycin (mTOR) signaling pathway, DNA repair, c-jun N-terminal kinase (JNK)-pathway regulation, and cell cycle after hyperoxic reoxygenation was applied.Conclusion:Acute hypoxia induces HIF-1 targets independent of the reoxygenation regime applied. Hyperoxic reoxygenation affects pathways regulating cell growth and survival. DNA-damage–responsive genes are restricted to reoxygenation with 100% oxygen.

Oxidative Stress Biomarkers and Left Ventricular Hypertrophy in Children with Chronic Kidney Disease

Cardiovascular diseases remain the most frequent cause of morbidity and mortality in patients with chronic kidney disease (CKD). The aim of the study was to assess the association between oxidative stress biomarkers and cardiovascular risk factors and left ventricular hypertrophy in children with CKD. Material and Methods. The studied group consisted of 65 patients aged 1.4–18.6 (mean 11.2) years with stages 1 to 5 CKD. Serum oxidized low-density lipoprotein (oxLDL), protein carbonyl group, creatinine, cystatin C, albumin, lipids, high-sensitivity C-reactive protein, intercellular adhesion molecule-1, insulin, plasma renin activity, and aldosterone levels were measured. Patients were divided into groups depending on CKD stage. Anthropometric measurements, ambulatory blood pressure (BP) measurements, and echocardiography with left ventricular mass (LVM) calculation were performed. Results. Serum oxLDL strongly correlated with creatinine (R = 0.246; p = 0.048), cystatin C (R = 0.346; p = 0.006), total cholesterol (R = 0.500; p < 0.001), triglycerides (R = 0.524; p < 0.001), low-density lipoprotein concentrations (R = 0.456; p < 0.001), and 24 hour BP values of systolic (R = 0.492; p = 0.002), diastolic (R = 0.515; p < 0.001), and mean arterial pressure (R = 0.537; p < 0.001). A significant correlation between oxLDL levels and LVM z-scores (R = 0.299; p = 0.016) was found. Conclusions. Hypertension and dyslipidemia correlated with lipid oxidation in children with CKD. oxLDLs seem to be valuable markers of oxidative stress in CKD patients, correlating with left ventricular hypertrophy.

Correlation between early neonatal diet and atopic symptoms up to 5-7 years of age in very low birth weight infants: follow-up of randomized, double-blind study

The influence of early feeding on the risk of atopic diseases has been studied in full‐term newborns, not in very low birth weight infants (VLBW). The study evaluated effect of early feeding of VLBW infants with either cow’s milk‐based formula (CMF) or extensively hydrolyzed milk formula (HF) on incidence of atopic diseases and markers of atopy at 5‐7 years of age. This was a follow‐up of the randomized, double‐blind study evaluating the influence of different enteral feeding protocols on the early morbidity of VLBW infants. In the original study 80 children were randomly allocated into 2 groups receiving during first month of life HF (experimental group) or CMF (control group). At the age of 5‐7 years, 62 children among 74 available (84%) with mean birthweight 1124g were evaluated according to standardized ISAAC (International Study of Asthma and Allergies in Childhood) protocol. Total IgE level, specific IgE, lymphocyte CD4+CCR4+/CD4+CXCR3+ ratio and skin prick tests (SPT) were done. Prevalence of obvious allergic diseases was not significantly different between the studied groups (HF: 12/33; CMF: 6/29; RR [relative risk] HF vs CMF: 1.76; 95%CI [confidence interval]: 0.76–4.09). Comparison of atopic status across groups revealed similar rate of positive markers of atopy: IgE (RR: 2.57 95%CI: 0.91–8,08), SPT (RR: 5.13; 95%CI: 0.93–31.6), lymphocyte CD4+CCR4+/CD4+CXCR3+ ratio (OR: 2.32; 95%CI: 0.78–7.53) in the both studied groups. Based on the carried out follow‐up study we were unable to confirm the usefulness of hydrolyzed formula in prevention of allergy in an unselected cohort of very low birth weight infants.

Prematurity-Related Hypertension in Children and Adolescents

Due to the functional and structural immaturity of different organ systems, preterms have a higher rate of morbidity and mortality. The prevention and treatment of the complications of prematurity is a major challenge in perinatal health care. Recently, there have been several multicenter research trials analysing the impact of prematurity or low birth weight on the health problems of children and adolescents. Many of these studies deal with the issue of pediatric hypertension. An analysis of 15 studies conducted in the years 1998–2011, in which blood pressure values in ex-preterm children were measured, was performed. Comparison was based on several issues: measurement method, cohorts age, size, and birthweight. It has been proven that hypertension occurs more often in former preterm infants; however the etiologic pathways that cause this condition still remain unclear. Moreover, pediatric hypertension is a significant problem, because of its transformation into adult hypertension and increased cardiovascular risk later in life. Therefore it is crucial to introduce wide-spread screening and detection of elevated blood pressure, especially among prematurely born children.