ABSTRACT:The ductus arteriosus (DA), a fetal arterial shunt vessel between the proximal descending aorta and the pulmonary artery, closes shortly after birth. Initial functional closure as a result of the DA's smooth muscle contraction is followed by definite anatomical closure. The latter involves several complex mechanisms like endothelial cushion formation and smooth muscle cell migration resulting in fibrosis and sealing of the vessel. These complex steps indicate highly specialized functions of the DA vascular smooth muscle cells (VSMCs), endothelial cells, and fibroblasts. Herein, we describe a new reproducible method for isolating VSMCs, endothelial cells, and fibroblasts of high viability from fetal rat DA using immunomagnetic cell sorting. Purity of the different cell cultures was assessed by immunohistochemistry and flow cytometry and ranged between 85 and 94%. The capability of the VSMCs to react to hypoxic stimuli was assessed by intracellular calcium and ATP measurements and by VEGF mRNA expression analysis. VSMCs respond to hypoxia with decreases in intracellular calcium concentrations and ATP levels, whereas VEGF mRNA expression increased 3.2-fold. The purified vessel-specific different cell types are suitable for subsequent gene expression profiling and functional studies and provide important tools for improving our understanding of the complex processes involved in the closure of the DA. T he ductus arteriosus (DA) is a shunt which connects the proximal descending aorta and the main pulmonary artery (PA). During fetal life, it serves to bypass the pulmonary circulation. The DA closes shortly after birth, and pulmonary blood flow increases during late gestation (1). After birth, an abrupt increase in oxygen tension results in ductal constriction, which is further promoted by falling levels of prostaglandin E2 because of an increased pulmonary metabolism and the elimination of placental prostaglandin. DA medial smooth muscle contraction leads to wall thickening, luminal obliteration, and shortening of the vessel. Permanent sealing of the DA is a process generated by the infolding of the endothelium, neointima formation, subintimal disruption, and vasa vasorum ingrowth resulting in subsequent vessel fibrosis. Several major molecular pathways are known to be involved in this programmed proliferation during permanent closure of the DA, e.g. NO signaling, the system of VEGF-promoted angiogenesis, and the cyclooxygenase/prostaglandin system (2-5).However, many questions concerning the exact function and cross-talk of these signaling pathways and the molecular basis for failed DA closure still remain unanswered (6). Previous studies investigating molecular events in the duct were in part hampered by the lack of an in vitro model that allows to study the processes in question separately in each of the different cell types of the DA instead of using the whole vessel (7). Herein, we describe an improved and reproducible method to culture organotypic vascular smooth muscle cells (VSMCs), fibroblasts, and e...
Clinical, laboratory, and placental manifestations of perinatal listeriosis are highly variable. Herein, we retrospectively analyzed all patients treated for neonatal listeriosis at the Charité University Medical Center in Berlin, Germany, 1999-2013. A total of 16 cases were identified. In 14 patients listeriosis was confirmed in neonatal specimens, while in two only the placenta tested positive. Elevated C-reactive protein and/or interleukin-6 levels were only inconsistently found, while a marked white blood cell left shift was present in all infants, if available. All but one infant manifested symptoms on the first day of life. Most patients required respiratory support, while none developed meningoencephalitis as evidenced by clinical or cerebrospinal fluid findings. Two patients died, all other patients survived without sequelae. In conclusion, perinatal listeriosis is still associated with significant morbidity and mortality. Clinical and laboratory findings are highly heterogeneous, but extreme leukocyte left shift seems to be a common feature.
Background To assess the prognostic value of early echocardiographic indices of right ventricular function and vasoactive peptides for prediction of bronchopulmonary dysplasia (BPD) or death in very preterm infants. Methods Prospective study involving 294 very preterm infants (median [IQR] gestational age 28.4 [26.4–30.4] weeks, birth weight 1065 [800–1380] g), of whom 57 developed BPD (oxygen supplementation at 36 weeks postmenstrual age) and 10 died. Tricuspid annular plane systolic excursion (TAPSE), right ventricular index of myocardial performance (RIMP), plasma concentrations of mid-regional pro-atrial natriuretic peptide (MR-proANP) and C-terminal pro-endothelin-1 (CT-proET1) were measured on day 7 of life. Results RIMP was significantly increased (median [IQR] 0.3 [0.23–0.38] vs 0.22 [0.15–0.29]), TAPSE decreased (median [IQR] 5.0 [5.0–6.0] vs 6.0 [5.4–7.0] mm), MR-proANP increased (median [IQR] 784 [540–936] vs 353 [247–625] pmol/L), and CT-proET1 increased (median [IQR] 249 [190–345] vs 199 [158–284] pmol/L) in infants who developed BPD or died, as compared to controls. All variables showed significant but weak correlations with each other (rS -0.182 to 0.359) and predicted BPD/death with similar accuracy (areas under receiver operator characteristic curves 0.62 to 0.77). Multiple regression revealed only RIMP and birth weight as independent predictors of BPD or death. Conclusions Vasoactive peptide concentrations and echocardiographic assessment employing standardized measures, notably RIMP, on day 7 of life are useful to identify preterm infants at increased risk for BPD or death.
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