Cardiac adverse effects of early dexamethasone treatment in preterm infants: a randomized clinical trial

PDA management strategies and pulmonary hypertension in extreme preterm infants with bronchopulmonary dysplasia

BACKGROUND

Premature infants are at risk for developing pulmonary hypertension (PH) in the context of bronchopulmonary dysplasia (BPD). Studies suggest a potential link between prolonged patent ductus arteriosus (PDA) exposure and BPD-PH, though management strategies remain controversial.

METHODS

Retrospective echocardiographic evaluation of newborns <29 weeks gestational age with BPD at two distinct centers. Primary objective was to evaluate the relationship between center-specific PDA management strategies (interventional or conservative) and the prevalence of BPD-PH. BPD was defined as oxygen or respiratory support at 36 weeks post-menstrual age (PMA). The presence of PH was defined as either an estimated sPAP of ≥40 mmHg or sEI ≥1.3. Center A has a conservative PDA policy. Center B has a targeted interventional policy.

RESULTS

PH rates were similar between sites (21% vs 17%), while rates of PDA treatment was different (7% vs 81). Adjusted models did not demonstrate an association for center or PDA treatment exposure for PH and EI, although infants from Center A had echocardiography evidence of higher systolic eccentricity index (EI; 1.12 ± 0.19 vs 1.06 ± 0.15, p = 0.04). Markers of RV function (TAPSE and RV-FAC) were similar between groups.

CONCLUSION

In preterm infants <29 weeks with BPD, conservative PDA treatment policy was not associated with higher rate of pulmonary hypertension diagnosis.

IMPACT

The association between PDA-management approaches and the occurrence of BPD-associated pulmonary vascular disease in premature infants has sparsely been described. We found that a conservative policy, regarding the PDA, was not associated with an increase in pulmonary hypertension diagnosis. We identified that, in patients with BPD, echocardiographic metrics of LV performance were lower.

Xenografts Show Signs of Concentric Hypertrophy and Dynamic Left Ventricular Outflow Tract Obstruction After Orthotopic Pig-to-baboon Heart Transplantation

BACKGROUND

Orthotopic cardiac xenotransplantation has seen substantial advancement in the last years and the initiation of a clinical pilot study is close. However, donor organ overgrowth has been a major hurdle for preclinical experiments, resulting in loss of function and the decease of the recipient. A better understanding of the pathogenesis of organ overgrowth after xenotransplantation is necessary before clinical application.

METHODS

Hearts from genetically modified ( GGTA1-KO , hCD46/hTBM transgenic) juvenile pigs were orthotopically transplanted into male baboons. Group I (control, n = 3) received immunosuppression based on costimulation blockade, group II (growth inhibition, n = 9) was additionally treated with mechanistic target of rapamycin inhibitor, antihypertensive medication, and fast corticoid tapering. Thyroid hormones and insulin-like growth factor 1 were measured before transplantation and before euthanasia, left ventricular (LV) growth was assessed by echocardiography, and hemodynamic data were recorded via a wireless implant.

RESULTS

Insulin-like growth factor 1 was higher in baboons than in donor piglets but dropped to porcine levels at the end of the experiments in group I. LV mass increase was 10-fold faster in group I than in group II. This increase was caused by nonphysiological LV wall enlargement. Additionally, pressure gradients between LV and the ascending aorta developed, and signs of dynamic left ventricular outflow tract (LVOT) obstruction appeared.

CONCLUSIONS

After orthotopic xenotransplantation in baboon recipients, untreated porcine hearts showed rapidly progressing concentric hypertrophy with dynamic LVOT obstruction, mimicking hypertrophic obstructive cardiomyopathy in humans. Antihypertensive and antiproliferative drugs reduced growth rate and inhibited LVOT obstruction, thereby preventing loss of function.

Systemic corticosteroids for the prevention of bronchopulmonary dysplasia, a network meta-analysis

BACKGROUND

Despite considerable improvement in outcomes for preterm infants, rates of bronchopulmonary dysplasia (BPD) remain high, affecting an estimated 33% of very low birthweight infants, with corresponding long-term respiratory and neurosensory issues. Systemic corticosteroids can address the inflammation underlying BPD, but the optimal regimen for prevention of this disease, balancing of the benefits with the potentially meaningful risks of systemic corticosteroids, continues to be a medical quandary. Numerous studies have shown that systemic corticosteroids, particularly dexamethasone and hydrocortisone, effectively treat or prevent BPD. However, concerning short and long-term side effects have been reported and the optimal approach to corticosteroid treatment remains unclear.

OBJECTIVES

To determine whether differences in efficacy and safety exist between high-dose dexamethasone, moderate-dose dexamethasone, low-dose dexamethasone, hydrocortisone, and placebo in the prevention of BPD, death, the composite outcome of death or BPD, and other relevant morbidities, in preterm infants through a network meta-analysis, generating both pairwise comparisons between all treatments and rankings of the treatments.

SEARCH METHODS

We searched the Cochrane Library for all systematic reviews of systemic corticosteroids for the prevention of BPD and searched for completed and ongoing studies in the following databases in January 2023: Cochrane Central Register of Controlled Trials, MEDLINE, Embase, and clinical trial databases.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) in preterm infants (< 37 weeks' gestation) at risk for BPD that evaluated systemic corticosteroids (high-dose [≥ 4 mg/kg cumulative dose] dexamethasone, moderate-dose [≥ 2 to < 4 mg/kg] dexamethasone, low-dose [< 2 mg/kg] dexamethasone, or hydrocortisone) versus control or another systemic corticosteroid.

DATA COLLECTION AND ANALYSIS

Our main information sources were the systematic reviews, with reference to the original manuscript only for data not included in these reviews. Teams of two paired review authors independently performed data extraction, with disagreements resolved by discussion. Data were entered into Review Manager 5 and exported to R software for network meta-analysis (NMA). NMA was performed using a frequentist model with random-effects. Two separate networks were constructed, one for early (< seven days) initiation of treatment and one for late (≥ seven days) treatment initiation, to reflect the different patient populations evaluated. We assessed the certainty of evidence derived from the NMA for our primary outcomes using principles of the GRADE framework modified for application to NMA.

MAIN RESULTS

We included 59 studies, involving 6441 infants, in our analyses. Only six of the included studies provided direct comparisons between any of the treatment (dexamethasone or hydrocortisone) groups, forcing network comparisons between treatments to rely heavily on indirect evidence through comparisons with placebo/no treatment groups. Thirty-one studies evaluated early corticosteroid treatment, 27 evaluated late corticosteroid treatment, and one study evaluated both early and late corticosteroid treatments. Early treatment (prior to seven days after birth): Benefits:NMA for early treatment showed only moderate-dose dexamethasone to decrease the risk of BPD at 36 weeks' postmenstrual age (PMA) compared with control (RR 0.56, 95% CI 0.39 to 0.80; moderate-certainty evidence), although the other dexamethasone dosing regimens may have similar effects compared with control (high-dose dexamethasone, RR 0.71, 95% CI 0.50 to 1.01; low-certainty evidence; low-dose dexamethasone, RR 0.83, 95% CI 0.67 to 1.03; low-certainty evidence). Other early treatment regimens may have little or no effect on the risk of death at 36 weeks' PMA. Only moderate-dose dexamethasone decreased the composite outcome of death or BPD at 36 weeks' PMA compared with control (RR 0.77, 95% CI 0.60 to 0.98; moderate-certainty evidence).

HARMS

Low-dose dexamethasone increased the risk for cerebral palsy (RR 1.92, 95% CI 1.12 to 3.28; moderate-certainty evidence) compared with control. Hydrocortisone may decrease the risk of major neurosensory disability versus low-dose dexamethasone (RR 0.65, 95% CI 0.41 to 1.01; low-certainty evidence). Late treatment (at seven days or later after birth): Benefits: NMA for late treatment showed high-dose dexamethasone to decrease the risk of BPD both versus hydrocortisone (RR 0.66, 95% CI 0.51 to 0.85; low-certainty evidence) and versus control (RR 0.72, CI 0.59 to 0.87; moderate-certainty evidence). The late treatment regimens evaluated may have little or no effect on the risk of death at 36 weeks' PMA. High-dose dexamethasone decreased risk for the composite outcome of death or BPD compared with all other treatments (control, RR 0.69, 95% CI 0.59 to 0.80, high-certainty evidence; hydrocortisone, RR 0.69, 95% CI 0.58 to 0.84, low-certainty evidence; low-dose dexamethasone, RR 0.73, 95% CI 0.60 to 0.88, low-certainty evidence; moderate-dose dexamethasone, RR 0.76, 95% CI 0.62 to 0.93, low-certainty evidence).

HARMS

No effect was observed for the outcomes of major neurosensory disability or cerebral palsy. The evidence for the primary outcomes was of overall low certainty, with notable deductions for imprecision and heterogeneity across the networks.

AUTHORS' CONCLUSIONS

While early treatment with moderate-dose dexamethasone or late treatment with high-dose dexamethasone may lead to the best effects for survival without BPD, the certainty of the evidence is low. There is insufficient evidence to guide this therapy with regard to plausible adverse long-term outcomes. Further RCTs with direct comparisons between systemic corticosteroid treatments are needed to determine the optimal treatment approach, and these studies should be adequately powered to evaluate survival without major neurosensory disability.

Association of Gestational Age at Birth With Left Cardiac Dimensions at Near-Term Corrected Age Among Extremely Preterm Infants

BACKGROUND

Remodeling and altered ventricular geometry have been described in adults born preterm. Although they seem to have an adverse cardiac phenotype, the impact of various degrees of prematurity on cardiac development has been scarcely reported. In this study, we evaluated the impact of gestational age (GA) at birth on cardiac dimensions and function at near-term age among extremely preterm infants.

METHODS

This is a retrospective single-center cohort study of infants born at <29 weeks of GA between 2015 and 2019. Infants with available clinically acquired echocardiography between 34 and 43 weeks were included. Two groups were investigated: those born <26 weeks and those born ≥26 weeks. All measurements were done by an expert masked to clinical data using the raw images. The primary outcome was measurements of cardiac dimensions and function based on GA group. Secondary outcomes were the association between cardiac dimensions and postnatal steroid exposure and with increments of GA at birth.

RESULTS

A total of 205 infants were included (<26 weeks, n = 102; ≥26 weeks, n = 103). At time of echocardiography, weight (2.4 ± 0.5 vs 2.5 ± 0.5 kg, P = .86) and age (37.2 ± 1.6 vs 37.1 ± 1.9 weeks, P = .74) were similar between groups. There was no difference in metrics of right-sided dimensions and function. However, left-sided dimensions were decreased in infants born <26 weeks, including systolic left ventricle (LV) diameter (1.06 ± 0.20 cm vs 1.12 ± 0.18 cm, P = .02), diastolic LV length (2.85 ± 0.37 vs 3.02 ± 0.57 cm, P = .02), and estimated LV end-diastolic volume (5.36 ± 1.69 vs 6.01 ± 1.79 mL, P = .02).

CONCLUSIONS

In our cohort of very immature infants, birth at the extreme of prematurity was associated with smaller left cardiac dimensions around 36 weeks of corrected age. Future longitudinal prospective studies should evaluate further the impact of prematurity on LV development and performance and their long-term clinical impact.

Dose-related cardiac outcomes in response to postnatal dexamethasone treatment in premature lambs

BACKGROUND

Postnatal corticosteroids are used in the critical care of preterm infants for the prevention and treatment of bronchopulmonary dysplasia. We aimed to investigate the effects of early postnatal dexamethasone therapy and dose on cardiac maturation and morphology in preterm lambs.

METHODS

Lambs were delivered prematurely at ~128 days of gestational age and managed postnatally according to best clinical practice. Preterm lambs were administered dexamethasone daily at either a low-dose (n = 9) or a high-dose (n = 7), or were naïve to steroid treatment and administered saline (n = 9), over a 7-day time-course. Hearts were studied at postnatal Day 7 for gene expression and assessment of myocardial structure.

RESULTS

High-dose dexamethasone treatment in the early postnatal period led to marked differences in cardiac gene expression, altered cardiomyocyte maturation and reduced cardiomyocyte endowment in the right ventricle, as well as increased inflammatory infiltrates into the left ventricle. Low-dose exposure had minimal effects on the preterm heart.

CONCLUSION

Neonatal dexamethasone treatment led to adverse effects in the preterm heart in a dose-dependent manner within the first week of life. The observed cardiac changes associated with high-dose postnatal dexamethasone treatment may influence postnatal growth and remodeling of the preterm heart and subsequent long-term cardiac function.

Preterm Neonate With Dexamethasone-Induced Acute Hypertrophic Cardiomyopathy and Cardiogenic Shock

This case report describes an extremely low birth weight infant, born at 26-week gestational age, who developed hypertrophic cardiomyopathy (HCM) and cardiogenic shock a few hours after administration of a small dose of dexamethasone. Although cases of steroid-induced cardiomyopathy in preterm neonates are known in literature, their adverse effects are insidious and are transient in occurrence. This is the first report of HCM and cardiogenic shock occurring acutely after administration of small-dose dexamethasone. This neonate received small-dose dexamethasone initially to prevent reintubation, and again to facilitate successful extubation. Both occurrences were associated with acute cardiac decompensation with reduction in ejection fraction within hours of administration. Cardiac function subsequently improved with discontinuation of drug and use of inotropic pharmacotherapy. Studies outlined in this report show that steroid-induced HCM is known and not isolated to dexamethasone alone; however, little is known on the adverse effect of small-dose steroid in resulting acute cardiac decompensation. This case is of educational value in clinical practice by highlighting the potential adverse effects even at the smaller doses of dexamethasone currently recommended in extremely low birth weight infants.

Transient Global Ventricular Hypertrophy in a Patient With Multisystem Inflammatory Syndrome in Children (MIS-C) Correlated With High-Dose Glucocorticoid Treatment: A Case Report

Multisystem inflammatory syndrome in children (MIS-C) following SARS-CoV-2 infection has been shown to lead to depressed cardiac function. Standard treatment includes high-dose glucocorticoids (GC). We present the unusual case of a teenager who developed transient echocardiographic global ventricular hypertrophy following GC administration during his treatment for MIS-C, with the resolution of the hypertrophy after cessation of GC.

Cardiorespiratory adaptation to low-dose dexamethasone for lung disease in extremely preterm infants: A prospective echocardiographic study

The cardiovascular impact of dexamethasone (Dex) is not well understood. Most data are obtained from a 6 week, high-dose regimen, and are limited to findings of hypertension and cardiac hypertrophy. The present study ascertained the impact of low-dose Dex on cardiac indices when administered to extremely preterm infants for lung disease. A pre-post intervention prospective echocardiographic (Echo) study was undertaken, with cardiac assessments performed before and within 24 h after completion of first course of therapy (10 day regimen, cumulative 0.89 mg kg^-1 ). Thirty infants with a gestational age of 24.6 ± 1.1 weeks and birthweight of 612 ± 125 g, respectively, were studied. The age at Dex administration was 20 ± 9 days. Fractional inspired oxygen decreased from 0.7 ± 0.23 to 0.35 ± 0.14 (P < 0.001). Patent ductus arteriosus was noted in 20 infants at Echo1. At Echo2, the ductal diameter decreased from 2.16 ± 0.8 to 1.1 ± 0.8 mm (P = 0.0003), with complete closure in 7/20 (35%). A reduction in left pulmonary artery end-diastolic velocity was noted (17 ± 12 to 9 ± 10 cm s^-1 , P < 0.001). Pulmonary vascular resistance decreased (increased time to peak velocity/right ventricular ejection time, 0.2 ± 0.03 to 0.23  ± 0.03, P = 0.0001) and right ventricular systolic performance improved (tricuspid annular plane systolic excursion, 4.9 ± 0.8 to 5.5 ± 0.9 mm, P = 0.02). No significant changes in fractional shortening and left ventricular mass were noted. A significant increase in blood pressure was noted. As a percentage of pre-treatment baseline, the mean increase for systolic blood pressure was 20.3% (95% confidence interval = 14-26) on day 2 (P = 0.008). Low-dose Dex influenced cardiovascular parameters related to pulmonary circulation. KEY POINTS: Corticosteroid therapy is frequently used in preterm infants who are dependent on ventilator support. Echocardiographic studies in infants administered a 6 week course of steroids have noted left ventricular hypertrophy, outlet obstruction and hypertension, but no information is available on right heart indices. The cardiopulmonary effects of the current, significantly lesser cumulative dose (10 day regimen, commonly described as 'DART') have not been evaluated. The present study noted a significant influence on ductal and pulmonary circulation indices. Left heart architecture and function was maintained, whereas a significant but transient increase in blood pressure was noted.

Effect of Preterm Birth on Cardiac and Cardiomyocyte Growth and the Consequences of Antenatal and Postnatal Glucocorticoid Treatment

Preterm birth coincides with a key developmental window of cardiac growth and maturation, and thus has the potential to influence long-term cardiac function. Individuals born preterm have structural cardiac remodelling and altered cardiac growth and function by early adulthood. The evidence linking preterm birth and cardiovascular disease in later life is mounting. Advances in the perinatal care of preterm infants, such as glucocorticoid therapy, have improved survival rates, but at what cost? This review highlights the short-term and long-term impact of preterm birth on the structure and function of the heart and focuses on the impact of antenatal and postnatal glucocorticoid treatment on the immature preterm heart.

Morphometric analysis of developing zebrafish embryos allows predicting teratogenicity modes of action in higher vertebrates

The early identification of teratogens in humans and animals is mandatory for drug discovery and development. Zebrafish has emerged as an alternative model to traditional preclinical models for predicting teratogenicity and other potential chemical-induced toxicity hazards. To prove its predictivity, we exposed zebrafish embryos from 0 to 96 h post fertilization to a battery of 31 compounds classified as teratogens or non-teratogens in mammals. The teratogenicity score was based on the measurement of 16 phenotypical parameters, namely heart edema, pigmentation, body length, eye size, yolk size, yolk sac edema, otic vesicle defects, otoliths defects, body axis defects, developmental delay, tail bending, scoliosis, lateral fins absence, hatching ratio, lower jaw malformations and tissue necrosis. Among the 31 compounds, 20 were detected as teratogens and 11 as non-teratogens, resulting in 94.44 % sensitivity, 90.91 % specificity and 87.10 % accuracy compared to rodents. These percentages decreased slightly when referred to humans, with 87.50 % sensitivity, 81.82 % specificity and 74.19 % accuracy, but allowed an increase in the prediction levels reported by rodents for the same compounds. Positive compounds showed a high correlation among teratogenic parameters, pointing out at general developmental delay as major cause to explain the physiological/morphological malformations. A more detailed analysis based on deviations from main trends revealed potential specific modes of action for some compounds such as retinoic acid, DEAB, ochratoxin A, haloperidol, warfarin, valproic acid, acetaminophen, dasatinib, imatinib, dexamethasone, 6-aminonicotinamide and bisphenol A. The high degree of predictivity and the possibility of applying mechanistic approaches makes zebrafish a powerful model for screening teratogenicity.

Dexamethasone inhibits regeneration and causes ventricular aneurysm in the neonatal porcine heart after myocardial infarction

AIMS

Recently, we demonstrated that the hearts of neonatal pigs (2-day old) have regenerative capacity, likely driven by cardiac myocyte division, but this potential is lost immediately after postnatal day 3. However, it is unknown if corticosteroid, a broad anti-inflammatory agent, will abrogate the regenerative capacity in the hearts of neonatal pigs. The aim of the current study is to evaluate the effect Dexamethasone (Dex), a broad anti-inflammatory agent, on heart regeneration, structure, and function of the neonatal pigs' post-myocardial infarction (MI).

METHODS AND RESULTS

Dex (0.2 mg/kg/day) was injected intramuscularly into the neonatal pig (age: 2 days postnatal) during the first week post-MI. Myocardial scar and left ventricular function were determined by cardiac magnetic resonance (CMR) imaging. Bromodeoxyuridine (BrdU) pulse-chase labeling, histology, immunohistochemistry, and flow cytometry were performed to determine inflammatory cell infiltration, CM cytokinesis, and myocardial fibrosis. Dex injection during the first-week suppressed acute inflammation post-MI in the pig hearts. It inhibited BrdU incorporation to pig CMs and CM cytokinesis via inhibiting aurora-B protein expression which was associated with mature scar formation and thinned walls at the infarct site. CMR imaging showed Dex caused left ventricular aneurysm and poor ejection fraction.

CONCLUSIONS

Dex inhibited CM cytokinesis and functional recovery and caused ventricular aneurysm in the hearts of 2-day old pigs post-MI.

Dexamethasone causes defective glucose-6-phosphate dehydrogenase dependent antioxidant barrier through endoglin in pregnant and nonpregnant rats

Glucocorticoid therapy has been associated with adverse cardiometabolic effects during pregnancy. Inflammation-mediated cardiac dysfunction, an independent risk factor for morbidity and mortality, has been linked to defective glucose-6-phosphate dehydrogenase (G6PD) dependent antioxidant defenses and increased endoglin expression. We therefore sought to investigate the effects of dexamethasone (DEX) on cardiac endoglin and G6PD-dependent antioxidant defense. Twenty-four rats were randomly assigned to nonpregnant (PRE(-)), DEX-exposed nonpregnant (PRE(-) + DEX), pregnant (PRE(+)), and DEX-exposed pregnant (PRE(+) + DEX) rats, respectively (n = 6 per group). PRE(-) and PRE(+) rats received vehicle (per oral (po)), while PRE(-) + DEX and PRE(+) + DEX groups were administered DEX (0.2 mg/kg po) between gestational days 14 and 19, respectively. Results showed that DEX caused increased cardiac pro-inflammatory markers (adenosine deaminase (ADA) activity, endoglin, vascular cell adhesion molecule-1 (VCAM-1), tissue injury markers (LDH, GGT, AST, ALT, and ALP), metabolic disturbances (elevated fasting plasma glucose, free fatty acid (FFA), lactate, cardiac FFA, and lactate) and depressed G6PD-dependent antioxidant defenses (G6PD activity, reduced glutathione/oxidized glutathione ratio, and nitric oxide) in pregnant and nonpregnant rats. The present study demonstrates that DEX led to increased cardiac endoglin and VCAM-1 that is accompanied by defective G6PD-dependent antioxidant defenses but not cardiac lipid accumulation in both pregnant and nonpregnant rats.

Quantitative and systems pharmacology 4. Network-based analysis of drug pleiotropy on coronary artery disease

Despite recent advance of therapeutic development, coronary artery disease (CAD) remains one of the major issues to public health. The use of genomics and systems biology approaches to inform drug discovery and development have offered the possibilities for new target identification and in silico drug repurposing. In this study, we propose a network-based, systems pharmacology framework for target identification and drug repurposing in pharmacologic treatment and chemoprevention of CAD. Specifically, we build in silico models by integrating known drug-target interactions, CAD genes derived from the genetic and genomic studies, and the human protein-protein interactome. We demonstrate that the proposed in silico models can successfully uncover approved drugs and novel natural products in potentially treating and preventing CAD. In case studies, we highlight several approved drugs (e.g., fasudil, parecoxib, and dexamethasone) or natural products (e.g., resveratrol, luteolin, daidzein and caffeic acid) with new mechanism-of-action in chemical intervention of CAD by network analysis. In summary, this study offers a powerful systems pharmacology approach for target identification and in silico drug repurposing on CAD.

Evaluating the use of corticosteroids in preventing and treating bronchopulmonary dysplasia in preterm neonates

Approximately 15 million babies worldwide are born premature, and complications of prematurity are one of the leading causes of death in neonates. Neonatal respiratory distress syndrome (NRDS) and bronchopulmonary dysplasia (BPD) are two of the most common and serious consequences of prematurity. Synthetic corticosteroids, including dexamethasone, have been central in efforts to treat and prevent BPD. There is strong evidence to show that prenatal corticosteroids reduce infant mortality and the incidence of NRDS, leading to their widespread use in obstetric units. However, data suggest that they are not as effective in reducing the incidence of BPD as NRDS, which may be due to the multifactorial pathogenesis of BPD. On the other hand, the use of postnatal corticosteroids in preterm infants is much more controversial. They have been shown to improve lung function and help in reducing the need for mechanical ventilation. These benefits, however, are associated with a range of adverse short- and long-term effects. This review will discuss the benefits and consequences of corticosteroids in treating BPD and will examine alternative treatments and future research that may improve the understanding of BPD and inform clinical practice.

Dose-dependent effects of glucocorticoids on pulmonary vascular development in a murine model of hyperoxic lung injury

BACKGROUND

Exposure of neonatal mice to hyperoxia results in pulmonary vascular remodeling and aberrant phosphodiesterase type 5 (PDE5) signaling. Although glucocorticoids are frequently utilized in the NICU, little is known about their effects on the developing pulmonary vasculature and on PDE5. We sought to determine the effects of hydrocortisone (HC) on pulmonary vascular development and on PDE5 in a neonatal mouse model of hyperoxic lung injury.

METHODS

C57BL/6 mice were placed in 21% O2 or 75% O2 within 24 h of birth and received HC (1, 5, or 10 mg/kg subcutaneously every other day) or vehicle. At 14 d, right ventricular hypertrophy (RVH), medial wall thickness (MWT), lung morphometry, and pulmonary artery (PA) PDE5 activity were assessed. PDE5 activity was measured in isolated pulmonary artery smooth muscle cells exposed to 21 or 95% O2 ± 100 nmol/l HC for 24 h.

RESULTS

Hyperoxia resulted in alveolar simplification, RVH, increased MWT, and increased PA PDE5 activity. HC decreased hyperoxia-induced RVH and attenuated MWT. HC had dose-dependent effects on alveolar simplification. HC decreased hyperoxia-induced PDE5 activity both in vivo and in vitro.

CONCLUSIONS

HC decreases hyperoxia-induced pulmonary vascular remodeling and attenuates PDE5 activity. These findings suggest that HC may protect against hyperoxic injury in the developing pulmonary vasculature.

Hypertrophic Cardiomyopathy After a Single Dose of Dexamethasone in a Preterm Infant

Dexamethasone is widely used in preterm infants with severe pulmonary disease. Hypertrophic cardiomyopathy (HCM) is a transient side effect observed after multiple doses of dexamethasone. We report a preterm infant with myocardial hypertrophy after a single dose of dexamethasone (0.5 mg/kg) used to treat laryngeal edema secondary to prolonged intubation. A benign course was observed without left ventricular outflow tract obstruction and with recovery within 4 weeks. Myocardial effects of dexamethasone may be independent of dose and duration of treatment. The risk/benefit ratio must be carefully considered before using even a single dose of dexamethasone in preterm infants.

Effects of glucocorticoid exposure on growth and structural maturation of the heart of the preterm piglet

Inadequate maintenance of systemic blood flow in neonates following preterm birth is associated with increased morbidity and mortality, and may be due in part to structural immaturity of the myocardium. Maternal glucocorticoid administration is associated with improved cardiovascular function, and possibly promotes structural maturation of the myocardium. This study assessed the structural maturity of the myocardium in male and female preterm and term piglets, and preterm piglets exposed to a regimen of maternal glucocorticoids as used clinically. In preterm, term and glucocorticoid exposed preterm piglets cardiomyocyte maturity was examined by measuring the proportion of binucleated myocytes and the volumes of single living ventricular cardiomyocytes with fluorescence microscopy. Ventricular apoptosis and proliferation were measured by immunohistochemistry. Preterm piglet hearts had fewer binucleated myocytes, smaller myocytes, and more proliferative and fewer apoptotic nuclei than term hearts. Maternal glucocorticoid treatment resulted in increased binucleation with no increase in myocyte volume, and levels of proliferation and apoptosis that were more similar to the term heart. Atrial weights were increased and in female piglets there was an increase in the ratio of left to right ventricular weight. The observed changes in atrial mass and myocyte structural maturation correlated with changes in cardiac function of isolated hearts of littermates. In conclusion, the association between increased myocardial maturation following glucocorticoid exposure, improved cardiac function in littermates, and clinical improvement in human neonatal cardiac function exposed to antenatal glucocorticoids, suggests that glucocorticoid exposure contributes to improved cardiovascular function in preterm infants by promoting myocardial structural maturity.

Hypertrophic intraventricular flow obstruction after very-low-dose dexamethasone (Minidex) in preterm infants: case presentation and review of the literature

The use of dexamethasone in preterm infants developing bronchopulmonary dysplasia has been proven to be effective. Hypertrophic cardiomyopathy is a frequently reported, although transient, side effect of high-dose dexamethasone administration. The recent introduction of very low dexamethasone dose, called 'Minidex', promised equal effectiveness compared to high-dose dexamethasone without relevant side effects. Our study presents two patients developing hypertrophic cardiomyopathy with intraventricular cardiac obstruction after administration of 'Minidex'. Marked cardiac side effects may occur even during very-low-dose dexamethasone treatment in preterm neonates. Betablocker and discontinuation of dexamethasone seem to allow spontaneous reversal of myocardial hypertrophy and obstruction. After all, systematic surveys of the incidence of cardiac complications in a larger population of preterm infants treated with very low doses of dexamethasone are needed.

Evidence-based neonatal pharmacotherapy: postnatal corticosteroids

Corticosteroids are used in the neonatal intensive care unit primarily to treat two conditions: bronchopulmonary dysplasia (BPD) and hypotension (cardiovascular insufficiency). Historically, high-dose dexamethasone was used for BPD, but its use was later associated with adverse neurodevelopmental outcomes and decreased substantially. Data from randomized controlled trials regarding efficacy and safety of lower-dose dexamethasone therapy are insufficient to recommend its use. Hydrocortisone may be an alternative to dexamethasone, but again data are insufficient to support use. Hydrocortisone therapy is increasingly used to treat hypotension in critically ill newborns; however, the outcomes of this therapy must be evaluated in randomized trials.

Visual outcomes of treated periocular capillary haemangiomas in childhood: a 10-year review

PURPOSE

To report our experiences of treating periocular capillary haemangioma with particular emphasis on visual outcomes.

METHODS

Patients who underwent treatment for periocular capillary haemangioma were identified, and a chart review was performed.

RESULTS

There were seventeen patients in the study. The main indications for treatment were increased size of lesion with threat of amblyopia and partial or full pupil occlusion. Seven patients required more than one type of treatment. Fourteen patients had intralesional steroid treatment and six patients had oral steroids. Intralesional steroids gave variable results with minimal side-effects, oral steroids were very effective but 4 out of 6 patients developed side-effects. The average pretreatment astigmatism was 2.4D and post treatment this had reduced to 1.3D. Final visual outcomes were available for 15 patients, 13 had visual acuity of 6/7.5 or better, two were amblyopic with vision of 6/9-2 and 6/18.

CONCLUSION

In this study, intralesional steroids were used for localized lesions and oral steroids for diffuse haemangiomas with orbital involvement. Treatment especially with oral steroids was found to halt the proliferative phase and assist early haemangioma regression reducing ocular sequelae.

Controversies in the therapy of isolated congenital complete heart block

Controversies in the therapy of congenital complete heart block are reviewed in terms of the timing of pacemaker implantation, the type and complications of pacing and its role in the presence of myocardial dysfunction. Drug treatment may be useful in selected cases in the presence of pleural effusions, ascites and hydrops of the fetus, but have no effect on complete heart block. Administration of fluorinated steroids in anti-Ro antibody-positive mothers with the aim of preventing complete heart block has given controversial results. Because of the variety of the clinical presentations, especially in regard to pacing therapy, it is mandatory to refer patients with congenital complete heart block to specialized centers with adequate resources and experienced personnel.

Therapeutic manipulation of glucocorticoid metabolism in cardiovascular disease

The therapeutic potential for manipulation of glucocorticoid metabolism in cardiovascular disease was revolutionized by the recognition that access of glucocorticoids to their receptors is regulated in a tissue-specific manner by the isozymes of 11beta-hydroxysteroid dehydrogenase. Selective inhibitors of 11beta-hydroxysteroid dehydrogenase type 1 have been shown recently to ameliorate cardiovascular risk factors and inhibit the development of atherosclerosis. This article addresses the possibility that inhibition of 11beta-hydroxsteroid dehydrogenase type 1 activity in cells of the cardiovascular system contributes to this beneficial action. The link between glucocorticoids and cardiovascular disease is complex as glucocorticoid excess is linked with increased cardiovascular events but glucocorticoid administration can reduce atherogenesis and restenosis in animal models. There is considerable evidence that glucocorticoids can interact directly with cells of the cardiovascular system to alter their function and structure and the inflammatory response to injury. These actions may be regulated by glucocorticoid and/or mineralocorticoid receptors but are also dependent on the 11beta-hydroxysteroid dehydrogenases which may be expressed in cardiac, vascular (endothelial, smooth muscle) and inflammatory (macrophages, neutrophils) cells. The activity of 11beta-hydroxysteroid dehydrogenases in these cells is dependent upon differentiation state, the action of pro-inflammaotory cytokines and the influence of endogenous inhibitors (oxysterols, bile acids). Further investigations are required to clarify the link between glucocorticoid excess and cardiovascular events and to determine the mechanism through which glucocorticoid treatment inhibits atherosclerosis/restenosis. This will provide greater insights into the potential benefit of selective 11beta-hydroxysteroid dehydrogenase inhibitors in treatment of cardiovascular disease.

Muscle ring finger 1 mediates cardiac atrophy in vivo

Pathological cardiac hypertrophy, induced by various etiologies such as high blood pressure and aortic stenosis, develops in response to increased afterload and represents a common intermediary in the development of heart failure. Understandably then, the reversal of pathological cardiac hypertrophy is associated with a significant reduction in cardiovascular event risk and represents an important, yet underdeveloped, target of therapeutic research. Recently, we determined that muscle ring finger-1 (MuRF1), a muscle-specific protein, inhibits the development of experimentally induced pathological; cardiac hypertrophy. We now demonstrate that therapeutic cardiac atrophy induced in patients after left ventricular assist device placement is associated with an increase in cardiac MuRF1 expression. This prompted us to investigate the role of MuRF1 in two independent mouse models of cardiac atrophy: 1) cardiac hypertrophy regression after reversal of transaortic constriction (TAC) reversal and 2) dexamethasone-induced atrophy. Using echocardiographic, histological, and gene expression analyses, we found that upon TAC release, cardiac mass and cardiomyocyte cross-sectional areas in MuRF1(-/-) mice decreased approximately 70% less than in wild type mice in the 4 wk after release. This was in striking contrast to wild-type mice, who returned to baseline cardiac mass and cardiomyocyte size within 4 days of TAC release. Despite these differences in atrophic remodeling, the transcriptional activation of cardiac hypertrophy measured by beta-myosin heavy chain, smooth muscle actin, and brain natriuretic peptide was attenuated similarly in both MuRF1(-/-) and wild-type hearts after TAC release. In the second model, MuRF1(-/-) mice also displayed resistance to dexamethasone-induced cardiac atrophy, as determined by echocardiographic analysis. This study demonstrates, for the first time, that MuRF1 is essential for cardiac atrophy in vivo, both in the setting of therapeutic regression of cardiac hypertrophy and dexamethasone-induced atrophy.

A case of an infant with flail tricuspid valve due to spontaneous papillary muscle rupture: was neonatal lupus the culprit?

A 3-month-old infant presented in extremis with a flail tricuspid valve. The authors theorized that the genesis of her papillary muscle rupture was perinatal ischemia compounded by worsening pulmonary valvular stenosis leading to excessive fiber tension. Her underlying diagnosis of autoimmune-mediated heart block with endocardial fibroelastosis and prenatal glucocorticoid steroid treatment represents potentiating factors.

Congenital heart block: clinical features and therapeutic approaches

Isolated congenital heart block is strongly associated with anti-Ro antibodies. It occurs in 2% of anti-Ro antibody positive pregnancies with a recurrence rate of 17-19%. Mortality is high in the first year of life (12-41%) and is predominantly due to dilated cardiomyopathy. A prolonged QTc occurs in 15-22% of cases and minor structural defects such as atrial septal defects and patent arterial ducts are well recognized. The 'mechanical' PR interval can now be measured in utero allowing for the detection of first-degree heart block. Both first and second-degree heart block detected in utero respond to therapy with fluorinated steroids. Complete congenital heart block is not reversible. Progression from a normal PR interval to complete heart block can occur within a week. IVIG is under investigation for the prevention of recurrence of congenital heart block, while dexamethasone should not be used for this purpose due to unacceptable toxicity. Data on the use of fluorinated steroids for established complete heart block is conflicting, although their use in cases where there is evidence of hydrops, poor ventricular function or both is not controversial.

Left ventricular diastolic dysfunction in bronchopulmonary dysplasia

We report 2 infants with severe bronchopulmonary dysplasia in whom left ventricular diastolic dysfunction contributed to clinical abnormalities, including pulmonary hypertension and recurrent pulmonary edema. We speculate that close monitoring for left ventricular diastolic dysfunction may assist with clinical management and improve outcomes of infants with severe bronchopulmonary dysplasia.

Fetal growth restriction in preterm infants and cardiovascular function at five years of age

OBJECTIVES

We have previously reported an increased cardiac workload in newborn preterm small (SGA) infants, but not in infants appropriate for gestational age (AGA). We hypothesized that these cardiovascular changes will persist at follow-up at 5 years of age.

STUDY DESIGN

We assessed blood pressure, echocardiography, and skin perfusion with laser Doppler flowmetry in 22 SGA (821 +/- 248 g, 28.5 +/- 2.5 gestational weeks) and in 25 AGA (1065 +/- 241 g, 27.6 +/- 0.8 weeks) preterm children at age 5 years. Laser Doppler flowmetry also was used in 13 control children (3982 +/- 425 g, 40.4 +/- 1.8 weeks).

RESULTS

The preterm children in both the SGA and AGA groups had similar higher systolic blood pressures, increased interventricular septum thicknesses, and smaller left ventricular end-diastolic diameters compared with population reference values. Maximal endothelium-independent perfusion to sodium nitroprusside was higher and maximal endothelium-dependent perfusion to acetylcholine reached a plateau earlier in the AGA preterm group than in the control group.

CONCLUSIONS

Prematurity may impair cardiovascular function independently of intrauterine growth restriction. Altered cardiac dimensions and differences in perfusion responses may reflect increased cardiac afterload.

Glucocorticoids produce whole body insulin resistance with changes in cardiac metabolism

Insulin resistance is viewed as an insufficiency in insulin action, with glucocorticoids being recognized to play a key role in its pathogenesis. With insulin resistance, metabolism in multiple organ systems such as skeletal muscle, liver, and adipose tissue is altered. These metabolic alterations are widely believed to be important factors in the morbidity and mortality of cardiovascular disease. More importantly, clinical and experimental studies have established that metabolic abnormalities in the heart per se also play a crucial role in the development of heart failure. Following glucocorticoids, glucose utilization is compromised in the heart. This attenuated glucose metabolism is associated with altered fatty acid supply, composition, and utilization. In the heart, elevated fatty acid use has been implicated in a number of metabolic, morphological, and mechanical changes and, more recently, in "lipotoxicity". In the present article, we review the action of glucocorticoids, their role in insulin resistance, and their influence in modulating peripheral and cardiac metabolism and heart disease.

Characterization of T-cell population in children with prolonged fetal exposure to dexamethasone for anti-Ro/SS-A antibodies associated congenital heart block

The objectives of the study were to characterize the production, function and survival of T lymphocytes of children with prolonged fetal exposure to dexamethasone for anti-Ro/SS-A antibodies associated congenital complete heart block. The analysis of thymic function, studied by measuring the level of T-cell receptor excision circles, was performed by real time PCR, the composition of T-cell subpopulation was evaluated by flow cytometry and the T-cell diversity was assayed by heteroduplex analysis. T-cell competence was gauged at two functional levels by determining the proliferation and the number of T-cell divisions and by measuring gamma-interferon production after mitogenic stimulation. We observed that the thymic output, distribution of T-cell subsets, thymidine incorporation, number of T-cell divisions, and y-interferon production were comparable to those of age-matched control. On the contrary, heteroduplex analysis demonstrated the presence of both polyclonal and oligoclonal peripheral T-cell repertoires. In conclusion, the analysis of the T-cell compartment in children with prolonged intrauterine exposure to high dose dexamethasone did not disclose any relevant abnormality, except a restriction of T-cell receptor diversity in some patients.

Cardiac effects of a single course of antenatal betamethasone in preterm infants

AIM

To show the effects of a single course of antenatal betamethasone on cardiac measurements and systolic functions in premature newborn infants.

METHODS

Seventy six newborn infants with a gestational age of 25-33 weeks were included in the study. They were first classified according to their gestational age: 25-29 weeks (n = 28) and 30-33 weeks (n = 48). They were then reclassified as betamethasone positive (mother received one course of betamethasone) or betamethasone negative (mother did not receive any antenatal glucocorticoid treatment). Cross sectional M mode echocardiographic scans were performed during the first three postnatal days and at the end of the first and third weeks. Left interventricular septum (IVS), left ventricular posterior wall (LVPW), left ventricular end diastolic (LVED), and left ventricular end systolic (LVES) dimensions, aortic root (AO), and left atrial diameters (LAs) were measured. The IVS to LVPW ratio was calculated to identify asymmetrical septal hypertrophy.

RESULTS

In neither group was any statistically significant difference noted in IVS, LVED, LVES, LVPW, LA, and AO measurements during the three cardiac ultrasonography scans. Systolic function, as assessed by fractional shortening, was not significantly different in infants who received betamethasone antenatally, in either age group. There was no difference in the IVS/LVPW ratios between those who received antenatal steroid and those who did not for the 25-29 week and 30-33 week groups during these three consecutive scans.

CONCLUSION

One course of antenatal betamethasone did not affect the cardiac wall thicknesses and systolic function in premature infants.

Glucocorticoid Metabolism in the Human Fetal Lung: Implications for Lung Development and the Pulmonary Surfactant System

It has been nearly 35 years since Liggins and Howie first reported the benefits of antenatal glucocorticoid (GC) treatment to promote the maturation of the human fetal lung, and nearly that long since Pasqualini and colleagues demonstrated that the human fetal lung actively metabolizes GCs. Since that time, our understanding of the effects of GCs on fetal lung maturation and pulmonary surfactant production has increased dramatically. Similarly, characterization of the enzymes involved in GC metabolism has greatly expanded our understanding of GC signaling in target tissues. In man, the biologically active GC (cortisol) and the biologically inactive GC (cortisone) are interconverted by the tissue-specific expression of the type 1 and type 2 11beta-hydroxysteroid dehydrogenase enzymes (HSD1 and HSD2). Much of the research on GC metabolism in peripheral target tissues has focused on the role of HSD1 in amplifying the effects of GCs in liver and adipose tissue or on the role of HSD2 in blocking the effects of GCs in the kidney and placenta. In contrast, the role of GC metabolism in modulating the effects of GCs on fetal lung maturation and the pulmonary surfactant system in humans is less understood. The goal of this review article is to present a brief overview of the role of GCs in human fetal lung maturation and pulmonary surfactant production, and to familiarize the reader with the biochemistry of the metabolism of natural and synthetic GCs by the HSD enzymes. In addition, we will review data concerning the expression and activity of the HSD enzymes in the human fetal lung and contrast this to what is known about the HSD enzymes in the fetal rodent lung. Although rodents, rabbits, sheep, and several primates have been invaluable model systems for the study of fetal lung development, we have chosen to largely focus this review on human lung, since there are significant differences in GC metabolism between humans and other species.

Exposure to repeat doses of antenatal glucocorticoids is associated with altered cardiovascular status after birth

OBJECTIVE

To determine if exposure to more than one course of antenatal glucocorticoids is associated with changes in infant blood pressure and myocardial wall thickness in the first month after birth.

DESIGN

Prospective cohort study.

SETTING

Tertiary neonatal intensive care unit.

PARTICIPANTS

Mothers who were eligible for but declined to enter a randomised trial of repeated doses of antenatal glucocorticoids (ACTORDS)-that is, who had a singleton, twin, or triplet pregnancy at <32 weeks gestation, had received an initial course of glucocorticoids seven or more days previously, and were considered to be at continued risk of preterm birth.

MAIN OUTCOME MEASURES

Blood pressure daily for the first week then weekly until 4 weeks of age. End diastolic interventricular septal and left ventricular posterior wall (EDIVS and EDLVPW) thickness at 48-72 hours after birth.

RESULTS

Thirty seven women were enrolled and delivered 50 infants. Thirty mothers (39 infants) were exposed to one course of glucocorticoids, and seven mothers (11 infants) to more than one course. Blood pressures were higher in the first week after birth in infants exposed to multiple courses of glucocorticoids, and in infants with a latency between last exposure and delivery of less than seven days. Systolic blood pressure on day 1 was >2SD above published normal ranges in 67% of babies exposed to multiple courses and 24% of babies exposed to a single course of glucocorticoids (p = 0.04). There was no difference between groups in thickness of the EDIVS or EDLVPW. However, 44/50 (88%) babies had EDIVS and 49/50 (98%) babies had EDLVPW thickness >2 SD above the expected mean for birth weight and gestation. EDIVS but not EDLVPW thickness increased with increasing latency (mean 0.02 mm/day, p = 0.03).

CONCLUSION

Future randomised trials should assess the long term effects of exposure to antenatal glucocorticoids, particularly multiple courses, on the cardiovascular status of the infant.

Neonatal glucocorticosteroid treatment causes systolic dysfunction and compensatory dilation in early life: studies in 4-week-old prepubertal rats

Glucocorticosteroid treatment is widely used to prevent chronic lung disease in premature infants. Recent studies in adult rats, treated with dexamethasone in the neonatal period, report negative long-term effects on the heart and severely reduced life expectancy. We treated neonatal rats with dexamethasone and studied cardiac function after 4 wk (prepubertal age) to investigate whether the late effects as previously described are preceded by detectable alterations in cardiac function at a younger age. Male rat pups (n = 12) were injected intraperitoneally with dexamethasone on d 1, 2, and 3 (0.5, 0.3, and 0.1 mug/g) of life. Control pups (n = 10) received saline. At 4 wk the animals were anesthetized, and a pressure-conductance catheter was introduced into the left ventricle to measure pressure-volume loops. Cardiac function was measured and pressure-volume relations were determined to quantify intrinsic systolic and diastolic function. Subsequently, hearts were excised for histologic examination. Compared with saline-treated animals, dexamethasone-treated rats had a reduced ventricular weight (270 +/- 40 versus 371 +/- 23 mg, p < 0.001) and reduced systolic function (end-systolic elastance: 1.24 +/- 0.43 versus 2.50 +/- 1.39 mm Hg/muL, p = 0.028). Cardiac output was maintained and end-diastolic volume was increased (84 +/- 23 versus 59 +/- 19 microL, p = 0.012) indicating a state of compensatory dilatation. Heart rate, diastolic function, and systemic vascular resistance were unchanged. Neonatal dexamethasone treatment causes cardiac alterations that can be detected in the prepubertal period and that may precede severe cardiac dysfunction later in life. If our findings are confirmed in humans, this may have consequences for a large patient population and cardiac screening at young age may be indicated to enable secondary prevention.

Left ventricular hypertrophy with outflow tract obstruction-a complication of dexamethasone treatment for subglottic stenosis

To our knowledge, this is the 1st reported case of steroid-induced obstructive cardiomyopathy in a child being treated for subglottic stenosis. As well, although born at 27 weeks, our patient was over 4 kg and 4 months of age (44 weeks corrected gestational age). This appears to be a phenomenon chiefly involving premature babies in the neonatal period with no reports of this occurring in patients greater than 40 weeks corrected gestational age. Signs of cardiac hypertrophy include tachycardia, new cardiac murmur, increased oxygen requirements, decreased urine output, and decreased peripheral perfusion. Diagnosis and eventual recovery was confirmed with serial echocardiograms. Knowledge of this serious side effect of dexamethasone will allow otolaryngologists to intervene early and prevent a potentially deadly complication.

Giant Fetal Magnetocardiogram P Waves in Congenital Atrioventricular Block

Background— Cardiogram signal amplitude is a key index of hypertrophy but has not been investigated extensively in utero. In this study, magnetocardiography was used to assess P and QRS amplitude in normal subjects and subjects with fetal arrhythmia.

Methods and Results— The study cohort consisted of 68 normal fetuses and 25 with various arrhythmias: 9 reentrant supraventricular tachycardia (SVT), 2 ventricular tachycardia (VT), 2 sinus tachycardia, 2 blocked atrial bigeminy, 2 congenital second-degree atrioventricular (AV) block, and 8 congenital complete AV block. Subjects with congenital AV block, all presenting with bradycardia, showed large QRS amplitude, exceedingly large P-wave amplitude, and long P-wave duration. The 2 subjects with VT, both with poor ventricular function, also exhibited large P waves. SVT was associated with only moderate signal amplitude elevation.

Conclusions— The data imply that AV block in utero is accompanied by hypertrophy, which is more pronounced for the atria than the ventricles. We hypothesize that the hypertrophy results from a compensatory response associated with regulation of cardiac output and is likely to be observable in other arrhythmias and disease states. Magnetocardiography may be more sensitive than fetal echocardiography for detection of atrial hypertrophy in utero.

[Neonatal lupus syndrome: review of the literature]

PURPOSE

Neonatal lupus syndrome include skin lesions, hematological and hepatic disorders, and congenital heart block (CHB) in the absence of severe cardiac malformation. This rare disorder is closely linked to transplacental transport of anti-SSA/Ro and anti-SSB/La maternal antibodies.

CURRENT KNOWLEDGE AND KEY POINTS

The prevalence of CHB in newborns of anti-Ro/SSA positive women with known connective tissue disease is 2% and the risk of recurrence ranges from 10 to 17%. Skin and systemic lesions are transient, whereas CHB is definitive and is associated with significant morbidity and mortality (estimated at 16-19%). A pacemaker must be implanted in 2/3 of cases. Myocarditis may be associated or may appeared secondarily. Mothers of children with CHB are usually asymptomatic or have Gougerot-Sjögren, or undifferentiated connective tissue disease. Mothers of children with cutaneous manifestations may present with more severe disease and systemic lupus erythematosus. In anti-Ro/SSA positive pregnant women, echocardiograms should be performed at least every 2 weeks from 16 to 24 weeks gestation. Electrocardiogram should be performed for all children.

FUTURE PROSPECTS AND PROJECTS

The efficiency of prophylactic treatment of CHB is not established. Therapy for CHB detected in utero is not standardized and involves fluorinated steroids (especially betamethasone).

Does terbutaline damage the developing heart?

BACKGROUND

Beta(2)-Adrenoceptor (betaAR) agonists, such as terbutaline, are widely used to arrest preterm labor. They also cross the placenta where they stimulate receptors in fetal tissues, which in turn use betaAR input for trophic control of cell replication and differentiation.

METHODS

As rats are altricial, we administered terbutaline in two different postnatal exposure periods (10 mg/kg given daily on Days 2-5 or 11-14).

RESULTS

Hearts were examined twenty-four hours after the last dose and on postnatal day 30 for cardiac damage. Neither treatment paradigm caused an increase in cardiac abnormalities compared to controls but quantitative analysis of the number of nuclei indicated reductions in females.

CONCLUSIONS

These findings do not support earlier case reports of outright myocardial necrosis after terbutaline tocolysis in human infants. Nevertheless, the significant statistical association between terbutaline and cardiac anomalies in epidemiological studies suggest that terbutaline may sensitize the developing heart to other insults that affect development.

Pharmacokinetics in the newborn

In addition to differences in the pharmacodynamic response in the infant, the dose and the pharmacokinetic processes acting upon that dose principally determine the efficacy and/or safety of a therapeutic or inadvertent exposure. At a given dose, significant differences in therapeutic efficacy and toxicant susceptibility exist between the newborn and adult. Immature pharmacokinetic processes in the newborn predominantly explain such differences. With infant development, the physiological and biochemical processes that govern absorption, distribution, metabolism, and excretion undergo significant growth and maturational changes. Therefore, any assessment of the safety associated with an exposure must consider the impact of these maturational changes on drug pharmacokinetics and response in the developing infant. This paper reviews the current data concerning the growth and maturation of the physiological and biochemical factors governing absorption, distribution, metabolism, and excretion. The review also provides some insight into how these developmental changes alter the efficiency of pharmacokinetics in the infant. Such information may help clarify why dynamic changes in therapeutic efficacy and toxicant susceptibility occur through infancy.

A three year follow up of preterm infants after moderately early treatment with dexamethasone

OBJECTIVE

To assess the effect of moderately early postnatal dexamethasone treatment on growth and neurodevelopmental outcome in preterm infants.

METHODS

Thirty preterm infants enrolled in a randomised clinical trial to investigate the effectiveness of moderately early dexamethasone administration in the treatment of chronic lung disease were routinely followed up. Fifteen babies received a total dose of 4.75 mg/kg over 14 days from the 10th day of life, and 15 babies were untreated. Five infants in each group received open label steroids to facilitate extubation later in their clinical course. Growth and neurodevelopmental outcome are reported.

RESULTS

The mean body weight, height, and head circumference as well as the number of babies with anthropometric measurements within normal range were similar in treated and untreated babies. There was no significant difference between treated and control groups with respect to incidence of cerebral palsy, major neurosensory impairment, mean intelligence quotient scores, and behavioural abnormalities.

CONCLUSIONS

Postnatal dexamethasone treatment with the schedule used in this study did not impair growth and neurodevelopmental outcome in preterm infants. Data from larger trials have raised major concern that postnatal steroid treatment may increase neurodevelopmental impairment. The full extent of the risk will only be known when more trials have reported follow up data.

Controlled trial of early dexamethasone treatment for the prevention of chronic lung disease in preterm infants: a 3-year follow-up

OBJECTIVE

There is increasing concern in regard to the possible long-term adverse effects of postnatal dexamethasone treatment in preterm infants. The purpose of this study was to assess growth and neurodevelopmental outcome in preterm infants at high risk of chronic lung disease (CLD), treated with early (<96 hours) postnatal dexamethasone.

DESIGN

Three-year follow-up data of physical growth and neurodevelopmental outcome of preterm infants enrolled in a controlled trial to study the effectiveness of early postnatal dexamethasone administration for the prevention of CLD were reviewed. The original trial included 25 treated neonates who received dexamethasone intravenously from the fourth day of life for 7 days (0.5 mg/kg/d for the first 3 days, 0.25 mg/kg/d the next 3 days, and 0.125 mg/kg/d on the seventh day), and 25 untreated neonates as controls. Forty-five surviving infants (22 untreated and 23 treated) completed the 3-year follow-up.

RESULTS

At the end of follow-up, infants pertaining to both study groups had similar values for body weight, height, and head circumference, and a similar incidence of infants with anthropometrics data below the third percentile. Moreover, no differences were detected between the groups in regard to incidence of major cranial ultrasound abnormalities, cerebral palsy, major neurosensory impairment or IQ scores, and distribution.

CONCLUSIONS

Early (<96 hours) postnatal dexamethasone administration at the doses employed in this study did not impair physical or neurodevelopmental outcome in preterm infants at high risk of CLD. However, the small sample size of our study was not tailored to look for long-term outcomes and our results are not in agreement with those of larger trials and systematic reviews. The real risks of postnatal dexamethasone administration could be definitely assessed only when more well-designed trials using long-term neurodevelopmental assessment as the primary outcome will be reported.