Arnold Pollak

Vitamin D3 down-regulates monocyte TLR expression and triggers hyporesponsiveness to pathogen-associated molecular patterns.

Toll‐like receptors (TLR) represent an ancient front‐line defence system that enables the host organism to sense the presence of microbial components within minutes. As inducers of inflammation, TLR act as important triggers of distinct entities such as sepsis or autoimmune disease exacerbation. We report here that vitamin D3 [1α,25‐dihydroxycholecalciferol, 1,25(OH)2D3] suppresses the expression of TLR2 and TLR4 protein and mRNA in human monocytes in a time‐ and dose‐dependent fashion. Despite 1,25(OH)2D3‐induced up‐regulation of CD14, challenge of human monocytes with either LPS or lipoteichoic acid resulted in impaired TNF‐α and procoagulatory tissue factor (CD142) production, emphasizing the critical role of TLR in the induction of inflammation. Moreover, reduced TLR levels in 1,25(OH)2D3‐treated phagocytes were accompanied by impaired NF‐κB/RelA translocation to the nucleus and by reduced p38 and p42/44 (extracellular signal‐regulated kinase 1/2) phosphorylation upon TLR‐ligand engagement. Both TLR down‐regulation and CD14 up‐regulation were substantially inhibited by the vitamin D receptor (VDR) antagonist ZK 159222, indicating that the immunomodulatory effect of 1,25(OH)2D3 on innate immunity receptors requires VDR transcription factor activation. Our data provide strong evidence that 1,25(OH)2D3 primes monocytes to respond less effectively to bacterial cell wall components in a VDR‐dependent mechanism, most likely due to decreased levels of TLR2 and TLR4.

Immaturity of Infection Control in Preterm and Term Newborns Is Associated with Impaired Toll-Like Receptor Signaling

The impaired infection control related to the functional immaturity of the neonatal immune system is an important cause of infection in preterm newborns. We previously reported that constitutive Toll-like receptor (TLR) 4 expression and cytokine secretion on lipopolysaccharide (LPS) stimulation increases with gestational age. Here, we analyzed constitutive monocyte TLR2 expression and evaluated the expression profiles of the proximal downstream adapter molecule myeloid differentiation factor 88 (MyD88). We further investigated activation of protein kinases p38 and extracellular regulated kinsase (ERK) 1/2 in CD14 monocytes after ex vivo stimulation with bacterial TLR ligands (LPS and lipoteichoic acid [LTA]). The functional outcome of the stimulation was determined by cytokine secretion. Monocytes from 31 preterm newborns (<30 weeks of gestation, n=16; 30-37 weeks of gestation, n=15), 10 term newborns, and 12 adults were investigated. In contrast to TLR4 expression, TLR2 levels did not differ between age groups. However, MyD88 levels were significantly lower in preterm newborns. Activation of p38 and ERK1/2 was impaired in all newborn age groups after stimulation with TLR-specific ligands. Accordingly, after LTA stimulation, the levels of interleukin (IL)-1 beta , IL-6, and IL-8 cytokine production were substantially lower (P<.001) in preterm newborns than in adults. The reduced functional response to bacterial cell wall components appears to be part of the functional immaturity of the neonatal immune system and might predispose premature newborns to bacterial infection.

Neonatal screening for lysosomal storage disorders: feasibility and incidence from a nationwide study in Austria

BACKGROUND The interest in neonatal screening for lysosomal storage disorders has increased substantially because of newly developed enzyme replacement therapies, the need for early diagnosis, and technical advances. We tested for Gauchers disease, Pompes disease, Fabrys disease, and Niemann-Pick disease types A and B in an anonymous prospective nationwide screening study that included genetic mutation analysis to assess the practicality and appropriateness of including these disorders in neonatal screening panels. METHODS Specimens from dried blood spots of 34,736 newborn babies were collected consecutively from January, 2010 to July, 2010, as part of the national routine Austrian newborn screening programme. Anonymised samples were analysed for enzyme activities of acid β-glucocerebrosidase, α-galactosidase, α-glucosidase, and acid sphingomyelinase by electrospray ionisation tandem mass spectrometry. Genetic mutation analyses were done in samples with suspected enzyme deficiency. FINDINGS All 34,736 samples were analysed successfully by the multiplex screening assay. Low enzyme activities were detected in 38 babies. Mutation analysis confirmed lysosomal storage disorders in 15 of them. The most frequent mutations were found for Fabrys disease (1 per 3859 births), followed by Pompes disease (1 per 8684), and Gauchers disease (1 per 17,368). The positive predictive values were 32% (95% CI 16-52), 80% (28-99), and 50% (7-93), respectively. Mutational analysis detected predominantly missense mutations associated with a late-onset phenotype. INTERPRETATION The combined overall proportion of infants carrying a mutation for lysosomal storage disorders was higher than expected. Neonatal screening for lysosomal storage disorders is likely to raise challenges for primary health-care providers. Furthermore, the high frequency of late-onset mutations makes lysosomal storage disorders a broad health problem beyond childhood. FUNDING Austrian Ministry of Health, Family, and Women.

Monocyte Toll-Like Receptor 4 Expression and LPS-Induced Cytokine Production Increase during Gestational Aging

Premature newborns are highly susceptible to severe bacterial infections. This is partially due to their immature innate immune system, characterized by decreased neutrophil and monocyte activity as well as by reduced concentrations of complement factors. However, additional mechanisms might be important for innate immunity and are still the subject of considerable debate. The importance of pattern recognition domains such as Toll-like receptors (TLR) has been fully acknowledged within the last few years. Therefore, we investigated age-related monocyte TLR4 expression and lipopolysaccharide-induced cytokine secretion from very low birth weight infants (VLBWI) and from newborns after wk 30 of gestation in comparison to healthy adults. In VLBWI, expression of TLR4 surface protein, detected by flow cytometry, and TLR4-specific mRNA, quantified by real time-PCR, were significantly reduced in comparison to mature infants and to adults. Reduced TLR4 expression was paralleled by significantly diminished ex vivo LPS stimulated IL-1β, IL-6, and tumor necrosis factor-α secretion into whole blood. We conclude that, in VLBWI, the minimized expression of TLR4 contributes to the susceptibility of VLBWI to infections with Gram-negative bacteria due to the lack of cytokines to boost initial immune response.

Prenatal diagnosis of congenital toxoplasmosis: A multicenter evaluation of different diagnostic parameters☆☆☆★

OBJECTIVE Our purpose was to evaluate different methods of diagnosing congenital toxoplasmosis prenatally by amniocentesis and cordocentesis. STUDY DESIGN In a retrospective multicenter study, we investigated consecutive women who had seroconversion for Toxoplasma gondii during pregnancy and who underwent either amniocentesis or cordocentesis or both to obtain a prenatal diagnosis of fetal toxoplasmosis. Data were obtained from 122 patients recruited in 6 different European Toxoplasma reference centers. Infants born to these mothers were followed up until 1 year of age to confirm or exclude congenital toxoplasmosis. Sensitivity, specificity, positive predictive value, and negative predictive value were measured for the following parameters: (1) detection of the parasite in amniotic fluid by mouse inoculation, (2) detection of the parasite in amniotic fluid by in vitro cell culture, (3) detection of Toxoplasma deoxyribonucleic acid in amniotic fluid by a polymerase chain reaction assay, (4) detection of the parasite in fetal blood by mouse inoculation, (5) detection of specific immunoglobulin M antibodies in fetal blood, and (6) detection of specific immunoglobulin A antibodies in fetal blood. RESULTS The polymerase chain reaction test performed on amniotic fluid had the highest level of sensitivity (81%) and also a high level of specificity (96%). The combination of the polymerase chain reaction test and mouse inoculation of amniotic fluid increased sensitivity to 91%. The sensitivity of immunoglobulins M and A in fetal blood was 47% and 38%, respectively. In congenitally infected fetuses a negative correlation was observed between positive serologic parameters and gestational age at the time of maternal infection and at prenatal diagnosis. CONCLUSION Congenital toxoplasmosis is best predicted by prenatal examination with the combination of T gondii polymerase chain reaction and mouse inoculation of amniotic fluid. The role of cordocentesis in the diagnosis of congenital toxoplasmosis is limited.

Perinatal lead and mercury exposure in Austria

OBJECTIVE The heavy metals lead (Pb) and mercury (Hg) are ubiquitous environmental pollutants with high neurotoxic potential. We aimed to compare perinatal Pb and Hg concentrations and to explore the potential association between Pb and Hg exposure and newborn anthropometry. STUDY DESIGN Pregnant women were recruited in 2005 at the General Hospital Vienna for participation in this longitudinal study. Pb and Hg concentrations were measured in maternal blood and hair, placenta, cord blood, meconium, and breast milk of 53 mother-child pairs by CV-AAS, GF-AAS, and HPLC-CV-ICPMS. We conducted bivariate analyses and categorical regression analysis (CATREG) to evaluate the determinants of Pb and Hg exposure, and of infant anthropometry. RESULTS Median Pb and total Hg contents were low, i.e., 25 μg/L (maternal blood-Pb), 13 μg/L (cord blood-Pb), 0.7 μg/L (maternal blood-Hg), and 1.1 μg/L (cord blood-Hg). Hg levels in maternal and fetal tissues were frequently correlated (r>0.3, P<0.05, respectively). Regarding Pb, only maternal blood and cord blood concentrations correlated (P=0.043). Cord blood levels indicated higher Hg exposure but lower Pb exposure relative to maternal blood contents. Adjusted CATREG models indicated the significant predictors of birth length (placenta-Pb, gestational length, meconium-Pb), birth weight (placenta-Pb, gestational length, maternal blood-Pb), and head circumference (maternal education, maternal height). Besides one significant correlation between maternal hair Hg and birth length, the mercury levels were not associated with newborn anthropometry. CONCLUSIONS Our data implicate that different modes of action may exist for placentar transfer of Pb and Hg as well as that low Pb exposure levels can result in lower birth weight. The findings related to newborn anthropometry need to be confirmed by the examination of larger study groups. Further research is needed to clarify the mechanisms of Pb and Hg transfer via the placenta, and to explore how prenatal Pb exposure is related to intrauterine growth.

Association between prenatal treatment and clinical manifestations of congenital toxoplasmosis in infancy: A cohort study in 13 European centres

Aim: To determine the effectiveness of prenatal treatment for clinical manifestations of congenital toxoplasmosis. Methods: We prospectively identified 255 live‐born infants with congenital toxoplasmosis using prenatal or neonatal screening. We determined the effect of prenatal treatment on the risks of intracranial or ocular lesions in infancy, accounting for gestational age at maternal seroconversion. Results: Prenatal treatment within 4 wk of seroconversion reduced the risk of intracranial lesions compared with no treatment (odds ratio, OR 0.28; 95% CI: 0.08–0.75), but there was no significant effect when initiated after 4 wk (OR 0.76; 95% CI: 0.35–1.59; overall p‐value 0.19). Compared to spiramycin alone, no treatment doubled the risk of intracranial lesions (OR 2.33; 95% CI: 1.04–5.50), but the risk did not differ with pyrimethamine‐sulphonamide treatment (overall p‐value 0.52). There was no consistent relationship between the type or timing of treatment and the risk of ocular lesions. Gestational age at maternal seroconversion was inversely associated with the risk of intracranial but not ocular lesions.

Effect of tracheal suction on oxygenation, circulation, and lung mechanics in newborn infants.

Transcutaneous PO2, heart rate, and aortic blood pressure were measured i 10 mechanically-ventilated newborn infants to assess the degree and course of hypoxaemia, and to monitor the cardiovascular and respiratory changes during tracheal toilet. Five infants weighed less than 1250 (mean 994), g and 5 infants weighed greater than 1750 (mean 2216) g. During tracheal suction the TcPO2 fell from 68 +/- 27 (mean +/- SD) to 43 +/- 23 mmHg, and the heart rate from 144 +/- 8 to 123 +/- 25 beats/minute, but the blood pressure increased from 44 to +/- 24 to 49 +/- 24 mmHg. Hypoxaemia (TcPO2 less than 50 mmHg) occurred in 7 of 8 initially well-oxygenated infants when suctioned. The decrease in TcPO2 was similar for both groups of infants. It was greater in infants with controlled ventilation and an F1O2 greater than or equal to 0.8 than in infants with intermittent mandatory ventilation and an F1O2 less than 0.8. The TcPO2 fall correlated well with the TcPO2 during the control period but not during the time that the infants were disconnected from the respirator. A critical re-evaluation of routine tracheal toilet is needed.

Diagnosis of congenital toxoplasmosis in the neonatal period: A multicenter evaluation.

OBJECTIVE To evaluate different laboratory tests used to diagnose congenital toxoplasmosis in the neonatal period. STUDY DESIGN A retrospective multicenter study of 294 pregnant women who experienced seroconversion for Toxoplasma gondii and subsequently delivered live-born infants. Fetal infection was assessed via specific IgM and IgA antibodies (cord and neonatal blood) and detection of T gondii in placenta and cord blood by mouse inoculation. RESULTS Ninety-three (32%) of the 294 infants were congenitally infected. The sensitivity of IgA in cord blood and in neonatal blood was 64% and 66%; the sensitivity of IgM was 41% and 42%, respectively. Mouse inoculation of the placenta and cord blood had sensitivities of 45% and 16%. Positive results of the serologic tests in congenitally infected children correlated significantly with the gestational age at the time of maternal infection but was not significantly influenced by the administration of specific antiparasitic treatment during pregnancy. CONCLUSION Specific T gondii IgA antibody is a more sensitive test than IgM for detecting congenital toxoplasmosis in the neonatal period. The overall specificity is better for serologic tests performed on neonatal blood than for those on cord blood. Neonatal screening with IgM or IgA antibodies will not detect the majority of children with congenital toxoplasmosis when the maternal infection occurred before the 20th week of pregnancy.

Pulsatile secretion of gonadotropins in early infancy

In adults, luteinizing hormone (LH) and follicle stimulating hormone (FSH) are secreted in a pulsaltile manner. Prior to puberty gonadotropin (GN) levels are low and show only small fluctuations. The following investigation was performed to elucidate the type of GN secretion in infants:LH and FSH were determined every 30 min over a period of 8 h in three different groups: Group 1:2 male and 2 female adults; Group 2:2 male and 2 female prepubertal children; Group 3:3 male and 3 female infants, aged 6–12 weeks.Group 1 showed a clear pulsatile secretion of LH (4.5–23.5 mIU/ml [range]) and FSH (6.9–16.0 mIU/ml). Group 2 demonstrated a rather constant secretion of LH (<1.5–2.3 mIU/ml) and FSH (1.6–4.9 mIU/ml). Group 3: In male infants pulsatile secretion of LH (3.6–34.7 mIU/ml)—and to a lesser degree of FSH (1.8–4.6 mIU/ml)—were found. In female infants the pulsatile secretion of FSH (6.5–22.7 mIU/ml) was more pronounced than that of LH (<1.5–4.7 mIU/ml). The secretory pattern in early infancy is of a pulsatile type.