Matthias Roth-Kleiner

Estradiol and Progesterone Strongly Inhibit the Innate Immune Response of Mononuclear Cells in Newborns

ABSTRACT Newborns are particularly susceptible to bacterial infections due to qualitative and quantitative deficiencies of the neonatal innate immune system. However, the mechanisms underlying these deficiencies are poorly understood. Given that fetuses are exposed to high concentrations of estradiol and progesterone during gestation and at time of delivery, we analyzed the effects of these hormones on the response of neonatal innate immune cells to endotoxin, bacterial lipopeptide, and Escherichia coli and group B Streptococcus, the two most common causes of early-onset neonatal sepsis. Here we show that at concentrations present in umbilical cord blood, estradiol and progesterone are as powerful as hydrocortisone for inhibition of cytokine production by cord blood mononuclear cells (CBMCs) and newborn monocytes. Interestingly, CBMCs and newborn monocytes are more sensitive to the effects of estradiol and progesterone than adult peripheral blood mononuclear cells and monocytes. This increased sensitivity is associated with higher expression levels of estrogen and membrane progesterone receptors but is independent of a downregulation of Toll-like receptor 2 (TLR2), TLR4, and myeloid differentiation primary response gene 88 in newborn cells. Estradiol and progesterone mediate their anti-inflammatory activity through inhibition of the NF-κB pathway but not the mitogen-activated protein kinase pathway in CBMCs. Altogether, these results suggest that elevated umbilical cord blood concentrations of estradiol and progesterone acting on mononuclear cells expressing high levels of steroid receptors contribute to impair innate immune responses in newborns. Therefore, intrauterine exposure to estradiol and progesterone may participate in increasing susceptibility to infection during the neonatal period.

Genetic control of lung development.

Lung organogenesis is a developmental process that starts in human 4–5 weeks after conception and continues during the first years of life. It can be subdivided in six different stages: embryonic, pseudoglandular, canalicular, saccular andalveolar stage and stage of vascular maturation. In each of these periods, multiple molecules like transcription factors, growth factors and other signaling molecules and their respective receptors control and coordinate the course of events by a distinct expression and activity over space and time. Epithelial-mesenchymal interactions, physiological mechanical forces as well as humoral factors modulate some of these expression patterns. Although numerous key players and their mode of action have been discovered, many wait to be unveiled. Herein, we will summarize the current concepts of lung development with special consideration of the genetic control of lung genesis, growth and maturation.

Increasing incidence of respiratory distress in neonates

Aim: To document the change in the incidence of respiratory distress (RD), related interventions and mortality in neonates admitted to primary, secondary and tertiary neonatal units within a geographically defined population over a period of 30 years.

Lipopolysaccharide exposure modifies high tidal volume ventilation-induced proinflammatory mediator expression in newborn rat lungs.

Infection/inflammation and mechanical ventilation have both independently been shown to increase cytokine/chemokine levels in lung tissue and blood samples of premature patients. Little is known about the combined effect of systemic inflammation and mechanical ventilation on cytokine expression in the lung. We tested whether pre-existing inflammation induced by lipopolysaccharide (LPS) exposure would modify cytokine/chemokine response in newborn rat lungs to high tidal volume ventilation (HTVV). Newborn rats were randomly assigned to four groups: groups I and II (saline); groups III and IV: 3 mg/kg LPS. Groups II and IV were 24h later subjected to 3h of ventilation with a tidal volume of 25 mL/kg. HTVV alone increased IL-1β, IL-6 and the chemokine (C-X-C motif) ligand 2 (CXCL2) mRNA expression. Although the cytokine response to LPS alone had disappeared after 24 h, the combination of LPS pretreatment and HTVV significantly increased the expression of IL-6 and IL-1β mRNA when compared with HTVV alone. TNF-α expression was increased neither by HTVV alone nor in combination with LPS. IL-6 protein content in bronchoalveolar lavage increased due to the combined treatment. Thus, a subtle pre-existing inflammation combined with HTVV amplifies the proinflammatory cytokine/chemokine expression in the newborn rat lung compared with HTVV alone.

Bronchial Muscle Peristaltic Activity in the Fetal Rat

Aside for the potential for tonic contraction, the airway smooth muscle exhibits intermittent phasic rhythmic activity that may contribute to lung growth during fetal life. Therefore, we examined 4th generation rat 18–22 d gestation fetal, 4–6 d of age newborn and adult bronchial ring from Sprague Dawley rats to compare differences in smooth muscle function. We hypothesized that phasic contractions were greatest before birth. Bronchial muscle spontaneous rhythmic contractions were greatest in the fetus and absent in the adult. In response to KCl stimulation, the fetal bronchial smooth muscle only developed tonic force that was 3.5 ± 0.6 and lower than measured in the newborn 9.0 ± 0.3 and adult 13.7 ± 1.4mN/mm2. The thromboxane A2 analogue U46619 induced tonic and phasic muscle contractions and the amplitude and frequency of the phasic contractions were greater in the fetus as compared with the adult and increased with gestational age. The U46619-induced rhythmic contractions were abrogated by ryanodine, thapsigargin and reduction of extracellular Na+, suggesting intracellular Ca2+ dependence and involvement of the Na+/Ca2+ exchanger. The inward rectifier K+ blocker BaCl2 induced phasic contractions in unstimulated fetal, but not adult bronchial muscle of the same amplitude and frequency as for the spontaneous and U46619-induced ones. We conclude that the airway smooth muscle phasic activity is greatest in the fetus and tends to disappear post-natally with age suggesting an in utero role during lung development.

Swiss medical centres vary significantly when it comes to outcomes of neonates with a very low gestational age

This study quantified the impact of perinatal predictors and medical centre on the outcome of very low‐gestational‐age neonates (VLGANs) born at <32 completed weeks in Switzerland.

Evaluation of different POCT devices for glucose measurement in a clinical neonatal setting

Hypoglycaemia is a major cause of neonatal morbidity and may induce long-term developmental sequelae. Clinical signs of hypoglycaemia in neonatal infants are unspecific or even absent, and therefore, precise and accurate methods for the assessment of glycaemia are needed. Glycaemia measurement in newborns has some particularities like a very low limit of normal glucose concentration compared to adults and a large range of normal haematocrit values. Many bedside point-of-care testing (POCT) systems are available, but literature about their accuracy in newborn infants is scarce and not very convincing. In this retrospective study, we identified over a 1-year study period 1,324 paired glycaemia results, one obtained at bedside with one of three different POCT systems (Elite™ XL, Ascensia™ Contour™ and ABL 735) and the other in the central laboratory of the hospital with the hexokinase reference method. All three POCT systems tended to overestimate glycaemia values, and none of them fulfilled the ISO 15197 accuracy criteria. The Elite XL appeared to be more appropriate than Contour to detect hypoglycaemia, however with a low specificity. Contour additionally showed an important inaccuracy with increasing haematocrit. The bench analyzer ABL 735 was the most accurate of the three tested POCT systems. Both of the tested handheld glucometers have important drawbacks in their use as screening tools for hypoglycaemia in newborn infants. ABL 735 could be a valuable alternative, but the blood volume needed is more than 15 times higher than for handheld glucometers. Before daily use in the newborn population, careful clinical evaluation of each new POCT system for glucose measurement is of utmost importance.

Neonatal treatment of CINCA syndrome

Chronic Infantile Neurological Cutaneous Articular (CINCA) syndrome, also called Neonatal Onset Multisystem Inflammatory Disease (NOMID) is a chronic disease with early onset affecting mainly the central nervous system, bones and joints and may lead to permanent damage. We report two preterm infants with severe CINCA syndrome treated by anti-interleukin-1 in the neonatal period, although, so far, no experience with this treatment in infants younger than three months of age has been reported. A review of the literature was performed with focus on treatment and neonatal features of CINCA syndrome.Case reportTwo cases suspected to have CINCA syndrome were put on treatment with anakinra in the early neonatal period due to severe clinical presentation. We observed a rapid and persistent decline of clinical signs and systemic inflammation and good drug tolerance. Diagnosis was confirmed in both cases by mutations in the NLRP3/CIAS1-gene coding for cryopyrin. As particular neonatal clinical signs polyhydramnios and endocardial overgrowth are to be mentioned.ConclusionWe strongly suggest that specific treatment targeting interleukin-1 activity should be started early. Being well tolerated, it can be introduced already in neonates presenting clinical signs of severe CINCA syndrome in order to rapidly control inflammation and to prevent life-long disability.

Evolution of gene expression changes in newborn rats after mechanical ventilation with reversible intubation

Mechanical ventilation (MV) is life‐saving but potentially harmful for lungs of premature infants. So far, animal models dealt with the acute impact of MV on immature lungs, but less with its delayed effects. We used a newborn rodent model including non‐surgical and therefore reversible intubation with moderate ventilation and hypothesized that there might be distinct gene expression patterns after a ventilation‐free recovery period compared to acute effects directly after MV. Newborn rat pups were subjected to 8 hr of MV with 60% oxygen (O2), 24 hr after injection of lipopolysaccharide (LPS), intended to create a low inflammatory background as often recognized in preterm infants. Animals were separated in controls (CTRL), LPS injection (LPS), or full intervention with LPS and MV with 60% O2 (LPS + MV + O2). Lungs were recovered either directly following (T:0 hr) or 48 hr after MV (T:48 hr). Histologically, signs of ventilator‐induced lung injury (VILI) were observed in LPS + MV + O2 lungs at T:0 hr, while changes appeared similar to those known from patients with chronic lung disease (CLD) with fewer albeit larger gas exchange units, at T:48 hr. At T:0 hr, LPS + MV + O2 increased gene expression of pro‐inflammatory MIP‐2. In parallel anti‐inflammatory IL‐1Ra gene expression was increased in LPS and LPS + MV + O2 groups. At T:48 hr, pro‐ and anti‐inflammatory genes had returned to their basal expression. MMP‐2 gene expression was decreased in LPS and LPS + MV + O2 groups at T:0 hr, but no longer at T:48 hr. MMP‐9 gene expression levels were unchanged directly after MV. However, at T:48 hr, gene and protein expression increased in LPS + MV + O2 group. In conclusion, this study demonstrates the feasibility of delayed outcome measurements after a ventilation‐free period in newborn rats and may help to further understand the time‐course of molecular changes following MV. The differences obtained from the two time points could be interpreted as an initial transitory increase of inflammation and a delayed impact of the intervention on structure‐related genes. Pediatr Pulmonol. 2012; 47:1204–1214.

Prospective evaluation of three point of care devices for glycemia measurement in a neonatal intensive care unit.

Hypoglycemia, if recurrent, may have severe consequences on cognitive and psychomotor development of neonates. Therefore, screening for hypoglycemia is a daily routine in every facility taking care of newborn infants. Point-of-care-testing (POCT) devices are interesting for neonatal use, as their handling is easy, measurements can be performed at bedside, demanded blood volume is small and results are readily available. However, such whole blood measurements are challenged by a wide variation of hematocrit in neonates and a spectrum of normal glucose concentration at the lower end of the test range. We conducted a prospective trial to check precision and accuracy of the best suitable POCT device for neonatal use from three leading companies in Europe. Of the three devices tested (Precision Xceed, Abbott; Elite XL, Bayer; Aviva Nano, Roche), Aviva Nano exhibited the best precision. None completely fulfilled the ISO-accuracy-criteria 15197: 2003 or 2011. Aviva Nano fulfilled these criteria in 92% of cases while the others were <87%. Precision Xceed reached the 95% limit of the 2003 ISO-criteria for values ≤4.2 mmol/L, but not for the higher range (71%). Although validated for adults, new POCT devices need to be specifically evaluated on newborn infants before adopting their routine use in neonatology.