Introducing enteral feeding induces intestinal subclinical inflammation and respective chromatin changes in preterm pigs.

AIM: To analyze how enteral food introduction affects intestinal gene regulation and chromatin structure in preterm pigs. MATERIALS & METHODS: Preterm pigs were fed parenteral nutrition plus/minus slowly increasing volumes of enteral nutrition. Intestinal gene-expression and chromatin structure were analyzed 5 days after birth. RESULTS: Enteral feeding led to differential upregulation of inflammatory and pattern recognition receptor genes, including IL8 (median: 5.8, 95% CI: 3.9-7.8 for formula; median: 2.2, 95% CI: 1.3-3.3 for colostrum) and TLR4 (median: 3.7, 95% CI: 2.6-4.8 for formula; no significant differences for colostrum) with corresponding decondensed chromatin configurations. On histology this correlated with mild mucosal lesions, particularly in formula-fed pigs. In CaCo-2 cells, histone hyperacetylation led to a marked increase in TLR4 mRNA and increased IL8 expression upon stimulation with lipopolysaccharide (median: 7.0; interquartile range: 5.63-8.85) compared with naive cells (median 4.2; interquartile range: 2.45-6.33; p = 0.03). CONCLUSION: Enteral feeding, particular with formula, induces subclinical inflammation in the premature intestine and more open chromatin structure in key inflammatory genes. This may increase the susceptibility for necrotizing enterocolitis.

CpG signalling, H2A.Z/H3 acetylation and microRNA-mediated deferred self-attenuation orchestrate foetal NOS3 expression.

BACKGROUND: An adverse intrauterine environment leads to permanent physiological changes including vascular tone regulation, potentially influencing the risk for adult vascular diseases. We therefore aimed to monitor responsive NOS3 expression in human umbilical artery endothelial cells (HUAEC) and to study the underlying epigenetic signatures involved in its regulation. RESULTS: NOS3 and STAT3 mRNA levels were elevated in HUAEC of patients who suffered from placental insufficiency. 5-hydroxymethylcytosine, H3K9ac and Histone 2A (H2A).Zac at the NOS3 transcription start site directly correlated with NOS3 mRNA levels. Concomitantly, we observed entangled histone acetylation patterns and NOS3 response upon hypoxic conditions in vitro. Knock-down of either NOS3 or STAT3 by RNAi provided evidence for a functional NOS3/STAT3 relationship. Moreover, we recognized massive turnover of Stat3 at a discrete binding site in the NOS3 promoter. Interestingly, induced hyperacetylation resulted in short-termed increase of NOS3 mRNA followed by deferred decrease indicating that NOS3 expression could become self-attenuated by co-expressed intronic 27 nt-ncRNA. Reporter assay results and phylogenetic analyses enabled us to propose a novel model for STAT3-3'-UTR targeting by this 27-nt-ncRNA. CONCLUSIONS: An adverse intrauterine environment leads to adaptive changes of NOS3 expression. Apparently, a rapid NOS3 self-limiting response upon ectopic triggers co-exists with longer termed expression changes in response to placental insufficiency involving differential epigenetic signatures. Their persistence might contribute to impaired vascular endothelial response and consequently increase the risk of cardiovascular disease later in life.

Correlation of viral load of respiratory pathogens and co-infections with disease severity in children hospitalized for lower respiratory tract infection.

BACKGROUND: The clinical significance of viral load and co-infections in children with respiratory infections is not clear. OBJECTIVE: To evaluate the correlation of viral load as well as viral and bacterial co-infections with disease severity in hospitalized children with lower respiratory tract infections (LRTIs). STUDY DESIGN: This is a prospective study conducted in children admitted for LRTIs for two seasons. To determine viral and bacterial load of respiratory pathogens we performed multiplex real-time polymerase chain reaction and semiquantitative bacterial cultures on nasopharyngeal aspirates (NPA). RESULTS: During the study period 244 (60%) children were hospitalized for LRTI with acute virus-induced wheezing and 160 (40%) for radiologic confirmed pneumonia. In the first NPA, viruses were identified in 315 (78%) of the 404 samples and bacteria in 198 (63.3%) of 311 samples. The viral load significantly decreased between the first and second NPA sample in most single and viral co-infections, except rhinovirus and human bocavirus infections. Viral load was inversely related to CRP in RSV infections, whereas a positive correlation was observed in adenovirus infections. Duration of hospitalization was significantly longer in RSV single infections compared to rhinovirus single infections whereas in the latter, leucocytosis and use of systemic steroids was more common. In RSV viral co-infections the presence of fever, leucocytosis, and the use of antibiotics was significantly more frequent. Positive cultures of Haemophilus influenzae dominated in RSV and rhinovirus single infections and Moraxella catarrhalis in RSV viral co-infections. CONCLUSIONS: Specific viral single and co-infections as well as viral load contribute to disease severity in children with LRTIs.