Neurodevelopmental outcome after COX inhibitor treatment for patent ductus arteriosus.

AIM: To compare neurodevelopmental results in very low birth weight (VLBW) infants two years after successful or failed cyclooxygenase inhibitor treatment with either indomethacin or ibuprofen for a haemodynamically significant patent ductus arteriosus (hsPDA). METHODS: We retrospectively evaluated closure rates and outcome parameters of VLBW infants with hsPDA 89 of whom were treated with indomethacin and 93 with ibuprofen. RESULTS: Indomethacin and ibuprofen therapy groups did not differ in their baseline clinical profile (median gestational age 26.0 and 26.2wksd) in early (median CRIB 6 and 5, respiratory distress >2 degrees in 36 and 34 infants) and late morbidities (intraventricular hemorrhage >2 degrees in 9 and 10 infants, bronchopulmonary dysplasia in 31 and 27 infants, 80 and 85 survivors), PDA closure rates (63 and 58%) or neurodevelopmental outcome. The therapy failure group (54 infants) was characterized by lower median gestational age (25.0wksd) and higher mortality (17%). No differences were found in the neurodevelopmental outcome of the surviving infants with ligation as compared to the survivors with successful pharmacological closure of the PDA at 24months corrected age. CONCLUSION: Use of either ibuprofen or indomethacin for closure of a hsPDA did not influence two year neurodevelopmental outcomes in VLBW infants.

Total serum bilirubin levels during cyclooxygenase inhibitor treatment for patent ductus arteriosus in preterm infants.

AIM: To determine whether ibuprofen use in VLBW infants is associated with increased serum bilirubin levels and impaired neurodevelopmental outcome at 2 years of age compared to indomethacin. METHODS: We retrospectively evaluated bilirubin data and outcome parameters of 178 VLBW infants treated with COX inhibitors for a haemodynamically relevant patent ductus arteriosus (PDA) between 1998 and 2003 in a single institution. In our department ibuprofen replaced indomethacin for PDA treatment in 2001, while clinical and echocardiographic criteria for the indication of PDA invention have remained unchanged. RESULTS: Ibuprofen and indomethacin therapy groups did not differ in their baseline clinical profile. Peak serum bilirubin concentration was 10.2 mg/dL in the ibuprofen group and 8.6 mg/dL in the indomethacin group (p < 0.01), while phototherapy duration did not differ. At 2 years of age neurodevelopmental outcome was similar in both groups. In a single case analysis, four cases of adverse neurodevelopmental outcome despite inconspicuous clinical course were identified in the ibuprofen group. CONCLUSION: In VLBW infants with PDA, ibuprofen treatment was associated with higher bilirubin levels than indomethacin.

[Doppler echocardiographic investigation of left ventricular diastolic function in preterm infants with and without a patent ductus arteriosus]. / Doppler-echokardiographische Untersuchungen der diastolischen Funktion des linken Ventrikels bei Frühgeborenen mit persistierendem und ohne persistierenden Ductus arteriosus.

We studied the influence of preload augmentation on Doppler-derived left ventricular diastolic function parameters in infants with a birth weight <1500 g. In 44 neonates with a closed duct and 29 neonates with an open ductus arteriosus a complete echocardiographic study including Doppler investigations of the mitral inflow signals and analysis of diastolic time intervals was performed. Neonates with an open duct had a lower median gestational age (27.1 vs. 29, P<0.01), a higher cardiac index (425 vs. 260 ml/min/kg, P<0.001), and a different M-mode left atrial to aortic diameter ratio (1.36 vs. 0.79, P<0.001), but birth weight, age at examination (6.6 vs. 7.9 days), and heart rate were similar compared to the neonates with a closed duct. Main differences in diastolic indexes existed in early and atrial filling integrals and peak velocities, early filling acceleration time, and isovolumic relaxation time. Most informative in neonates with an open ductus peak early filling velocity (41.2 vs. 30.4 cm, P<0.01) and peak atrial filling velocity (49.2 vs. 35.9, P<0.001) are higher, and isovolumic relaxation time is shorter (45 vs. 53 ms, P<0.001) than in closed duct peers. Isovolumic relaxation time is inversely correlated with the cardiac index (R = -0.78). These parameter changes can be interpreted as incipient left ventricular diastolic failure in extremely low birth weight infants in the presence of a preload challenge. The coincidence of higher peak velocities with a shortened isovolumic relaxation time is very likely a result of left atrial pressure elevation. Preload mismatch has to be considered in preterm infants with a persistent ductus arteriosus. The results of this study can be helpful to find the indication for PDA-closure and to adjust volume replacement therapy, and catecholamine medication to a level appropriate for the individual cardiac performance.

Elevated nerve growth factor and neurotrophin-3 levels in cerebrospinal fluid of children with hydrocephalus.

BACKGROUND: Elevated intracranial pressure (ICP) resulting from impaired drainage of cerebrospinal fluid (CSF) causes hydrocephalus with damage to the central nervous system. Clinical symptoms of elevated intracranial pressure (ICP) in infants may be difficult to diagnose, leading to delayed treatment by shunt placement. Until now, no biochemical marker of elevated ICP has been available for clinical diagnosis and monitoring. In experimental animal models, nerve growth factor (NGF) and neurotrophin-3 (NT-3) have been shown to be produced by glial cells as an adaptive response to hypoxia. We investigated whether concentrations of NGF and NT-3 are increased in the CSF of children with hydrocephalus. METHODS: NGF was determined in CSF samples collected from 42 hydrocephalic children on 65 occasions (taps or shunt placement surgery). CSF samples obtained by lumbar puncture from 22 children with suspected, but unconfirmed bacterial infection served as controls. Analysis was performed using ELISA techniques. RESULTS: NGF concentrations in hydrocephalic children were over 50-fold increased compared to controls (median 225 vs 4 pg/mL, p < 0.0001). NT-3 was detectable (> 1 pg/mL) in 14/31 hydrocephalus samples at 2-51 pg/mL but in none of 11 control samples (p = 0.007). CONCLUSION: NGF and NT-3 concentrations are increased in children with hydrocephalus. This may represent an adaptive response of the brain to elevated ICP.

Patent ductus arteriosus in very low birthweight infants: complications of pharmacological and surgical treatment.

AIMS: To evaluate complications of surgical and pharmacological treatment of symptomatic patent ductus arteriosus (PDA) in very low birthweight (VLBW) infants. PATIENTS AND METHODS: Of 931 VLBW infants consecutively admitted 1987-1998, a significant PDA prompted first-choice treatment by indomethacin in 101 infants, and surgery in 55 infants. PDA closed or became asymptomatic after indomethacin in 64 patients (63%), while 34 went on to surgery. PDA closure was achieved in all 61 infants after ligation and in 26 of 28 infants after clipping. RESULTS: Transient renal impairment after indomethacin treatment was recorded in 40 of 101 infants (40%), compared to renal impairment in 9 of 55 infants (16%) undergoing surgery without prior indomethacin. No differences in necrotizing enterocolitis and intracranial hemorrhage rates were seen. Air leak occurred in 6 of 89 infants after surgery, two of which had fatal tension pneumothorax. Intraoperative hemorrhage requiring emergency transfusion occurred in 2 infants, wound infection occurred in 2 infants and phrenic palsy in one infant. Based on an intention-to-treat analysis, the overall fatality rates were 16 of 101 (16%) for indomethacin and 14 of 55 (25%) for surgery. CONCLUSIONS: Despite the short-comings inherent to retrospective analyses, we propose that surgery should be reserved for infants not responding to pharmacological PDA closure.

Increased cerebrospinal fluid concentrations of soluble Fas (CD95/Apo-1) in hydrocephalus.

BACKGROUND AND AIMS: The ventricular enlargement observed in children with chronically raised intracranial pressure (ICP) causes a secondary loss of brain tissue. In animal studies of hydrocephalus, programmed cell death (apoptosis) has been found as a major mechanism of neuronal injury. One of the regulators of the apoptotic cell death programme is the receptor mediated Fas/Fas ligand interaction. METHODS: The apoptosis regulating cytokines soluble Fas (sFas) and soluble Fas ligand (sFasL) were studied in the cerebrospinal fluid (CSF) of 31 hydrocephalic children undergoing shunt surgery for symptomatic hydrocephalus and 18 controls. RESULTS: High concentrations of sFas were observed in children with hydrocephalus (median 252 ng/ml); in controls sFas was below the detection limit (0.5 ng/ml). sFasL was undetectable in all but one sample. CONCLUSION: High concentrations of sFas in the CSF of children with hydrocephalus suggest intrinsic sFas production, potentially antagonising pressure mediated Fas activation.

Tie2 receptor expression is stimulated by hypoxia and proinflammatory cytokines in human endothelial cells.

The tyrosine kinase receptor Tie2 (also known as Tek) plays an important role in the development of the embryonic vasculature and persists in adult endothelial cells (ECs). Tie2 was shown to be upregulated in tumors and skin wounds, and its ligands angiopoietin-1 and -2, although they are not directly mitogenic, modulate neovascularization. To gain further insight into the regulation of Tie2, we have studied the effect of hypoxia and inflammatory cytokines, two conditions frequently associated with neoangiogenic processes, on Tie2 expression in human ECs. Exposure to 1% O(2) led to a time-dependent significant rise of Tie2 protein levels in human coronary microvascular endothelial cells (HCMECs) and dermal microvascular ECs (HMEC-1) (3.2- and 2.5-fold within 24 hours), which was reversible after reoxygenation, and induced a less marked increase in human umbilical vein ECs (HUVECs; 1.7-fold). Hypoxia-conditioned medium and D-deoxyglucose did not change Tie2 expression, but desferrioxamine and cobalt, which are known to mimic hypoxia-sensing mechanisms, induced Tie2 at ambient oxygen tensions. Tumor necrosis factor-alpha induced Tie2 in a time- and dose-dependent fashion in all 3 EC types (HUVEC, 2.3-fold; HMEC-1, 2. 8-fold; and HCMEC, 3.0-fold; 10 ng/mL, 24 hours). Enhanced expression was also found after exposure to interleukin-1beta (1 ng/mL). Changes in Tie2 protein levels were paralleled by changes in mRNA expression. In accordance with these in vitro findings, immunohistochemistry revealed focal upregulation of Tie2 in capillaries at the border of infarcted human and rat myocardium. In conclusion, the data show that hypoxia and inflammatory cytokines upregulate Tie2, which may contribute to the angiogenic response in ischemic tissues.

Lack of hypoxic stimulation of VEGF secretion from neutrophils and platelets.

Low oxygen (O(2)) is the key stimulus for expression of vascular endothelial growth factor (VEGF) in several adherent cells. Whether hypoxia also directs the release of VEGF protein from neutrophils (polymorphonuclear neutrophils; PMN) and platelets has not been investigated. We therefore compared VEGF release of platelets, PMN, and human vascular smooth muscle cells (HSMC) in response to hypoxia with that to activators of cellular degranulation. In contrast to HSMC, VEGF release from PMN and platelets or VEGF mRNA expression in PMN was not stimulated under hypoxic conditions (1% O(2)). Hypo- or hyperthermia and acidosis, other conditions potentially associated with ischemic and inflammatory tissue injury, also did not stimulate VEGF secretion from PMN. However, stimulation of platelets with thrombin and of PMN with phorbol 12-myristate 13-acetate induced a time-dependent release of VEGF, peaking after 30 and 60 min, respectively. This was blocked by the degranulation inhibitor pentoxifylline but not by the protein-synthesis inhibitor cycloheximide. We conclude that rapid release of VEGF from platelets and PMN may occur independently of oxygenation during inflammation and hemostasis.

Regulation and differential expression of neutral endopeptidase 24.11 in human endothelial cells.

Neutral endopeptidase 24.11, a membrane-bound metallopeptidase, cleaves, and degrades vasoactive peptides such as atrial natriuretic peptide, endothelin, angiotensin I, substance P, and bradykinin. Therefore, the presence of this metallopeptidase may contribute to the regulation of vascular tone and local inflammatory responses in the vascular endothelium and elsewhere. We determined neutral endopeptidase in cultured human endothelial cells from different vascular beds and studied its regulation by protein kinase C. Neutral endopeptidase was detected in all cultured endothelial cell types. Lowest concentrations were measured in human endothelial cells from umbilical veins (360 +/- 14 pg/mg protein), followed by pulmonary and coronary arteries; higher concentrations were found in endothelial cells from the cardiac microcirculation (1099 +/- 73 pg/mg protein). Neutral endopeptidase content increased during cell growth but was not affected by endothelial cell growth factor or modifications of the growth medium. Stimulation of protein kinase C with 1-oleoyl-2-acetyl-rac-glycerol (0.1 to 1 mumol/L) and phorbol 12-myristate 13-acetate (0.01 to 0.1 mumol/L) induced a time- and concentration-dependent increase of endothelial cells that was inhibited by cycloheximide (5 mumol/L), an inhibitor of protein synthesis. Incubation with phospholipase C (1 mumol/L) and thrombin (10 IU/mL) induced upregulation of neutral endopeptidase, resulting in 158 +/- 26% and 150 +/- 22% increases, respectively, compared with controls. The thrombin effect was inhibited by calphostin C (1 mumol/L), an inhibitor of protein kinase C. Endothelial neutral endopeptidase is constitutively expressed in endothelial cells from different origins and is inducible by thrombin via activation of the protein kinase C pathway.