Safety and tolerability of subcutaneous treprostinil in newborns with congenital diaphragmatic hernia and life-threatening pulmonary hypertension.

BACKGROUND: Prolonged pulmonary hypertension (PH) is highly predictive for pulmonary morbidity and death in infants with congenital diaphragmatic hernia (CDH). OBJECTIVES: To report the effects and tolerability of subcutaneous treprostinil in newborns with severe CDH and late life-threatening PH. METHODS: We recorded clinical and echocardiography data before and after starting subcutaneous treprostinil, on patients with severe CDH and late PH, refractory to inhaled nitric oxide and oral sildenafil. RESULTS: 14 patients were treated with treprostinil (gestational age: 39.1±2.0weeks; birth weight: 3200±600g). Prior to treatment, the pre- and post-ductal SpO2 difference (Δ SpO2) was 14±10%. Treprostinil was initiated at a median age of 12days [5-157]. After starting treprostinil, ΔSpO2 decreased to 3% at day 7 (p<0.05), and the mean blood flow velocities in the right pulmonary arteries increased by 110% (p<0.05). 2 of the 14 patients died. At the age of follow up (12months to 3years), the 12 surviving infants were all weaned from respiratory support and discharged home. CONCLUSION: The subcutaneous treprostinil improves pulmonary hemodynamics and outcomes in infants with CDH and life-threatening PH. We suggest that the treatment should be considered in infants with severe CDH and late PH. TYPE OF STUDY: Case series with no comparison group. LEVEL OF EVIDENCE: Level IV.

Assessment of anti-factor Xa activity of heparin in binary parenteral nutrition admixtures for premature neonates.

An in vitro study was carried out to determine the anti-Xa activity of heparin in binary parenteral nutrition (BPN) admixtures for premature neonates in our neonatal intensive care unit (NICU) after a 24-hour infusion, as well as to assess drug interaction with a 50% glucose solution. Two types of bags were prepared: (1) BPN admixtures (composition defined in the NICU) including sodium heparin at 77 UI/mL and (2) bags containing only G50% with sodium heparin at 193 UI/mL. The anti-Xa activity of heparin was measured in bags at T0, after the 24-hour infusion and in eluates at the outlet of the infusion line after 24hours, using a validated chromogenic anti-Xa method. Comparisons of the mean concentration observed with the theoretical value for anti-Xa activity were performed with the Student t-test. Mean values of anti-Xa activity do not differ significantly from the values expected for all conditions. We found a slight variation in anti-Xa activity when infused over 24hours for both types of bags, with and without in-line filtration, showing that heparin remains stable during this infusion period in both BPN admixtures and G50%.

[Lung diseases in children associated with inherited disorders of surfactant metabolism]. / Pathologies respiratoires de l'enfant associées à des anomalies héréditaires du métabolisme du surfactant.

Pulmonary surfactant is a unique mixture of lipids and specific proteins that reduces surface tension at the air-liquid interface, preventing collapse of the lung at the end of expiration. Recessive loss-of-function mutations of pulmonary surfactant protein B (SP-B) was initially described in infants who develop respiratory failure at birth. More recently, mutations in other constitutive surfactant proteins like surfactant protein C or implied in its metabolism like ATP-binding cassette, sub-family A, member 3 (ABCA3) or NK2 homeobox (NKX2-1) were identified in newborn with respiratory distress but also in children with diffuse infiltrative pneumonia. Intra-alveolar accumulation of protein related to surfactant dysfunction leads to cough, hypoxemia and radiological abnormalities including ground-glass opacities and lung cysts. The clinical and radiological features associated with these genetic disorders, along with their treatment and outcome, are reviewed.

[Bronchopulmonary dysplasia-associated pulmonary arterial hypertension of very preterm infants]. / Hypertension artérielle pulmonaire des anciens grands prématurés bronchodysplasiques.

Bronchopulmonary dysplasia (BPD) of very preterm infants is a multifactorial chronic lung disease and its incidence has not decreased despite improvements in neonatal intensive care, including lung protective strategies. Pulmonary hypertension (PH) can complicate the course of BPD. Mortality in infants with BPD-associated PH is thought to be very high, but its incidence is unknown and a standard diagnostic and therapeutic strategy has not been well defined. In this article, we will first describe the current knowledge on the BPD-associated PH and the current treatments available for this pathology. We will then present the HTP-DBP Study, carried out in Paris (France) starting in 2012. The diagnosis of PH is suspected on echocardiographic criteria, but cardiac catheterization is considered the gold standard for diagnosis and evaluation of the severity of PH. Moreover, pulmonary vasoreactivity testing is used to guide the management of patients with PH. The pathogenesis of BPD-associated PH is poorly understood and even less is known about appropriate therapy. Today, optimizing ventilation and reducing the pulmonary vascular tone with specific pulmonary vasodilatator drugs are the main goals in treating HTP-associated DBP. Animal studies and a few clinical studies suggest that medications targeting the nitric oxide (NO) signaling pathway (NO inhalation, oral sildenafil citrate) could be effective treatments for BPD-associated PH, but they have not been approved for this indication. The HTP-DBP study is a French multicenter prospective observational study. The objective is to evaluate the frequency of BPD-associated PH, to describe its physiopathology, its severity (morbidity and mortality), and the effectiveness of current treatments.

[Genetic disorders of surfactant]. / Pathologies génétiques du surfactant.

Lung diseases associated with surfactant metabolism disorders represent a significant but heterogeneous group of rare disorders. Intra-alveolar accumulation of protein related to surfactant dysfunction leads to cough, hypoxemia and radiological diffuse infiltration. Inherited deficiency of pulmonary surfactant protein B (SP-B) was initially described in term newborns who develop severe respiratory failure at birth. More recently, mutations in surfactant protein C (SP-C) or in proteins required for surfactant synthesis such as ATP-binding cassette, sub-family A, member 3 (ABCA3) or NK2 homeobox 1 (NKX2-1) were identified in newborns with respiratory distress but also in children with diffuse infiltrative pneumonia. The aim of this review is to describe the clinical presentation of these diseases but also the diagnostic tools and the treatments options available.

Surfactant protein C gene (SFTPC) mutation-associated lung disease: high-resolution computed tomography (HRCT) findings and its relation to histological analysis.

AIM OF THE STUDY: Determine high-resolution tomography (HRCT) scan characteristics in children with SFTPC mutation and correlate them to histological findings. PATIENTS AND METHODS: This retrospective multicenter study included 15 children (7 females and 8 males) with SFTPC mutations. HRCT scans have been performed in all the children and lung biopsies in 8 children. RESULTS: From all signs assessed on initial HRCT scans, ground-glass opacities (n =14, 93%) and lung cysts (n = 6, 40%) were predominant. Interlobular septal thickening (n = 1, 7%), air space consolidation (n = 1, 7%), paraseptal emphysema (n = 2, 13%), and pulmonary nodules (n = 1, 7%) were also found. Histological analysis revealed accumulation of macrophages in the alveolar lumen, type II pneumocyte hyperplasia, and alveolar septal thickening. Dilatation of the respiratory bronchiole and alveolar duct associated with muscular hyperplasia were also described. Interestingly, lung cysts on HRCT scans were associated with dilatation of terminal bronchioli and alveolar duct in lung biopsies. CONCLUSION: In children with SFTPC mutations, HRCT scan finding was highly correlated to the histological findings and, as such, represent a useful tool to identify patients that may require SFTPC gene sequencing.

New surfactant protein C gene mutations associated with diffuse lung disease.

BACKGROUND: Mutations in the surfactant protein C gene (SFTPC) have been recently associated with the development of diffuse lung disease, particularly sporadic and familial interstitial lung disease (ILD). OBJECTIVE: We have investigated the prevalence and the spectrum of SFTPC mutations in a large cohort of infants and children with diffuse lung disease and suspected with surfactant dysfunction. METHOD AND RESULTS: 121 children were first screened for the common SFTPC mutation, p.Ile73Thr (I73T). Ten unrelated patients were shown to carry this mutation. The I73T mutation was inherited in six cases, and appeared de novo in four. The 111 patients without the I73T mutation were screened for the entire coding sequence of SFTPC. Of these, eight (seven unrelated) subjects were shown to carry a novel mutant allele of SFTPC. All these seven new mutations are located in the BRICHOS domain except the p.Val39Ala (V39A) mutation, which is in the surfactant protein C (SP-C) mature peptide. CONCLUSIONS: Our results confirm that SFTPC mutations are a frequent cause of diffuse lung disease, and that I73T is the most frequent SFTPC mutation associated with diffuse lung disease.