Modified natural surfactant preparations, used for treatment of respiratory distress syndrome in premature infants, contain phospholipids and the hydrophobic surfactant protein (SP)-B and SP-C. Herein, the individual and combined effects of SP-B and SP-C were evaluated in premature rabbit fetuses treated with airway instillation of surfactant and ventilated without positive end-expiratory pressure. Artificial surfactant preparations composed of synthetic phospholipids mixed with either 2% (wt/wt) of porcine SP-B, SP-C, or a synthetic poly-Leu analog of SP-C (SP-C33) did not stabilize the alveoli at the end of expiration, as measured by low lung gas volumes of approximately 5 ml/kg after 30 min of ventilation. However, treatment with phospholipids containing both SP-B and SP-C/SP-C33 approximately doubled lung gas volumes. Doubling the SP-C33 content did not affect lung gas volumes. The tidal volumes were similar in all groups receiving surfactant. This shows that SP-B and SP-C exert different physiological effects, since both proteins are needed to establish alveolar stability at end expiration in this animal model of respiratory distress syndrome, and that an optimal synthetic surfactant probably requires the presence of mimics of both SP-B and SP-C.

A disease similar to acute respiratory distress syndrome may occur in neonates after aspiration of meconium. The aim of the study was to compare the inhibitory effects of human meconium on the following surfactant preparations suspended at a concentration of 2.5 mg/mL: Curosurf, Alveofact, Survanta, Exosurf, Pumactant, rabbit natural surfactant from bronchoalveolar lavage, and two synthetic surfactants based on recombinant surfactant protein-C (Venticute) or a leucine/lysine polypeptide. Minimum surface tension, determined with a pulsating bubble surfactometer, was increased Ͼ10 mN/m at meconium concentrations Ն0.04 mg/mL for Curosurf, Alveofact, or Survanta, Ն0.32 mg/mL for recombinant surfactant protein-C, Ն1.25 mg/mL for leucine/lysine polypeptide, and Ն20 mg/mL for rabbit natural surfactant. The protein-free synthetic surfactants Exosurf and Pumactant did not reach minimum surface tension Ͻ10 mN/m even in the absence of meconium. We conclude that surfactant activity is inhibited by meconium in a dose-dependent manner. Recombinant surfactant protein-C and leucine/lysine polypeptide surfactant were more resistant to inhibition than the modified natural surfactants Curosurf, Alveofact, or Survanta but less resistant than natural lavage surfactant containing surfactant protein-A. We speculate that recombinant hydrophobic surfactant proteins or synthetic analogs of these proteins can be used for the design of new surfactant preparations that are relatively resistant to inactivation and therefore suitable for treatment of acute respiratory distress syndrome. Surfactant deficiency has been recognized as the cause of RDS in premature infants, and treatment with modified natural surfactant preparations has considerably improved the prognosis of this disease (1). However, it has been realized that secondary surfactant deficiency caused by inactivation of the surfactant system may occur in patients with mature lungs. In ARDS (acute (adult) RDS), surfactant inhibitors may reach the alveolar space by inhalation or aspiration, and proteins such as albumin or fibrinogen may leak into the airways as a consequence of increased vascular permeability caused by pneumonia, for example (2-4). To treat ARDS in such a patient, relatively large doses of surfactant need to be instilled to overcome the amount of surfactant inhibitors present in the airways (5). Thus, surfactant preparations used for treatment of ARDS should be relatively resistant to inactivation (6). Recent advances in the synthesis and heterologous expression of lung SPs or their analogs might allow the production of designer surfactants (7) that are highly resistant to surfactant inhibitors. Under ARDS-like conditions, such preparations may be superior to currently available modified natural surfactants.Aspiration of meconium can result in severe respiratory failure in term neonates (8 -10). Surfactant inactivation is believed to play a key role in the pathophysiology of MAS, and inhibition of the surface tension-lowering activity of surfactant by meconium has been...

The German Neonatal Network (GNN) is a prospective cohort study with the focus on long term development of very-low-birth-weight infants. It was the aim of this study to determine detailed information on causes of mortality in the GNN birth cohort 2010.Major contributors to hospital mortality were recorded by the attending neonatologists for the cohort of very-low-birth-weight (VLBW) infants born in centres of the German Neonatal Network (GNN) in 2010. The data quality was approved by on-site monitoring.2 221 VLBW infants were born in GNN centres in 2010, and death occurred in 221 infants. Male infants carried a higher risk than females (58.8% males among non-survivors vs. 51.7% among survivors, p=0.047). In 11 infants, the major contributor to death was not determined by the attending neonatologist. In 25 infants born at the limit of viability, comfort palliative care was primarily initiated and 14 infants had lethal malformations. The majority of non-survivors suffered from inflammatory diseases including sepsis- or necrotizing enterocolitis (NEC)-associated death (n=56). Respiratory pathology was a major contributor to death in 65 infants including 11 infants who died from pulmonary haemorrhage.Potentially preventable complications of preterm birth such as sepsis, NEC and pulmonary haemorrhage predominate the major contributors to mortality in the GNN 2010 cohort. In order to decrease the rate of these associated deaths, future trials should focus on prophylaxis and therapy optimization strategies for these outcomes.

ObjectiveTo determine if survival rates of preterm infants receiving active perinatal care improve over time.DesignThe German Neonatal Network is a cohort study of preterm infants with birth weight <1500 g. All eligible infants receiving active perinatal care are registered. We analysed data of patients discharged between 2011 and 2016.Setting43 German level III neonatal intensive care units (NICUs).Patients8222 preterm infants with a gestational age between 22/0 and 28/6 weeks who received active perinatal care.InterventionsParticipating NICUs were grouped according to their specific survival rate from 2011 to 2013 to high (percentile >P75), intermediate (P25–P75) and low (

Background: Surfactant dysfunction due to inhibition is involved in the pathophysiology of meconium aspiration syndrome. Dextran addition has been shown to reverse exogenous surfactant inactivation by meconium, but the precise mechanisms and the morphological correlate of this effect are yet unknown. Morphological surfactant analysis by transmission electron microscopy (TEM) and stereology allows the differentiation of active (large aggregates = LA) and inactive (small aggregates = SA) subtypes.