Observational study to compare the clinical efficacy of the natural surfactants Alveofact and Curosurf in the treatment of respiratory distress syndrome in premature infants

Targeting neutrophil extracellular traps: A novel strategy in hematologic malignancies

Neutrophil extracellular traps (NETs) have emerged as a critical factor in malignant hematologic disease pathogenesis. These structures, comprising DNA, histones, and cytoplasmic proteins, were initially recognized for their role in immune defense against microbial threats. Growing evidence suggests that NETs contribute to malignant cell progression and dissemination, representing a double-edged sword. However, there is a paucity of reports on its involvement in hematological disorders. A comprehensive understanding of the intricate relationship between malignant cells and NETs is necessary to explore effective therapeutic strategies. This review highlights NET formation and mechanisms underlying disease pathogenesis. Moreover, we discuss recent advancements in targeted inhibitor development for selective NET disruption, empowering precise design and efficacious therapeutic interventions for malignant hematologic diseases.

Comparing the clinical and economic efficiency of four natural surfactants in treating infants with respiratory distress syndrome

Surfactant therapy has revolutionized the treatment of respiratory distress syndrome (RDS) over the past few decades. Relying on a new method, the current research seeks to compare four common surfactants in the health market of Iran to determine the best surfactant according to the selected criteria. The research was a cross-sectional, retrospective study that used the data of 13,169 infants as recorded on the information system of the Iranian Ministry of Health. To rank the surfactants used, the following indicators were measured: re-dosing rate, average direct treatment cost, average length of stay, disease burden, need for invasive mechanical ventilation, survival at discharge, and medical referrals. The CRITIC (criteria importance through intercriteria correlation) method was used to determine the weight of the indicators, and MABAC (multi-attributive border approximation area comparison) was used to prioritize the surfactants. Based on the seven selected indicators in this research (re-dosing rate, average length of stay, direct medical cost per one prescription, medical referral rate, survival at discharge, disability-adjusted life years, number of newborns in need of invasive mechanical ventilation) and using multi-criteria analysis method, Alveofact was identified as the worst surfactant in infants with either more or less than 32 weeks' gestation. So that some criteria were worse in Alveofact group infants than other groups; for example, in the comparison of the Alveofact group with the average of the total population, it was found that the survival rate at discharge was 57.14% versus 66.43%, and the rate of re-dosing was 1.63 versus 1.39. BLES (bovine lipid extract surfactant) was the best alternative for infants more than 32 weeks' gestation, whereas Survanta was identified as best option for infants with less than 32 weeks' gestation. Curosurf showed an average level of functionality in the ranking. This study advises the policy makers in the field of neonatal health to increase the market share of more effective surfactants based on this study and other similar studies. On the other hand, neonatal health care providers are also advised to prioritize the use of more effective surfactants if possible, depending on the clinical conditions and desired improvements.

Breath-Synchronized Nebulized Surfactant in a Porcine Model of Acute Respiratory Distress Syndrome

Objectives

Effective treatment options for surfactant therapy in acute respiratory distress syndrome and coronavirus disease 2019 have not been established. To conduct preclinical studies in vitro and in vivo to evaluate efficiency, particle size, dosing, safety, and efficacy of inhaled surfactant using a breath-synchronized, nebulized delivery system in an established acute respiratory distress syndrome model.

Design

Preclinical study.

Setting

Research laboratory.

Subjects

Anesthetized pigs.

Intervention

In vitro analysis included particle size distribution and inhaled dose during simulated ventilation using a novel breath-synchronized nebulizer. Physiologic effects of inhaled aerosolized surfactant (treatment) were compared with aerosolized normal saline (control) in an adult porcine model (weight of 34.3 ± 0.6 kg) of severe acute respiratory distress syndrome (Pao₂/Fio₂ <100) with lung lavages and ventilator-induced lung injury during invasive ventilation.

Measurements and Main Results

Mass median aerosol diameter was 2.8 µm. In vitro dose delivered distal to the endotracheal tube during mechanical ventilation was 85% ± 5%. Nebulizers were functional up to 20 doses of 108 mg of surfactant. Surfactant-treated animals (n = 4) exhibited rapid improvement in oxygenation with nearly full recovery of Pao₂/Fio₂ (~300) and end-expiratory lung volumes with nominal dose less than 30 mg/kg of surfactant, whereas control subjects (n = 3) maintained Pao₂/Fio₂ less than 100 over 4.5 hours with reduced end-expiratory lung volume. There was notably greater surfactant phospholipid content and lower indicators of lung inflammation and pathologic lung injury in surfactant-treated pigs than controls. There were no peridosing complications associated with nebulized surfactant, but surfactant-treated animals had progressively higher airway resistance post treatment than controls with no differences in ventilation effects between the two groups.

Conclusions

Breath-synchronized, nebulized bovine surfactant appears to be a safe and feasible treatment option for use in coronavirus disease 2019 and other severe forms of acute respiratory distress syndrome.

The Inhibitory Effect of Curosurf® and Alveofact® on the Formation of Neutrophil Extracellular Traps

Background

Neutrophil extracellular traps (NETs) are a defense mechanism in which neutrophils cast a net-like structure in response to microbial infection. NETs consist of decondensed chromatin and about 30 enzymes and peptides. Some components, such as neutrophil elastase (NE) and myeloperoxidase (MPO), present antimicrobial but also cytotoxic properties, leading to tissue injury. Many inflammatory diseases are associated with NETs, and their final role has not been identified. Pulmonary surfactant is known to have immunoregulatory abilities that alter the function of adaptive and innate immune cells. The aim of this study was to investigate the hypothesis that natural surfactant preparations inhibit the formation of NETs.

Methods

The effect of two natural surfactants (Alveofact^® and Curosurf^®) on spontaneous and phorbol-12-myristate-13-acetate–induced NET formation by neutrophils isolated by magnetic cell sorting from healthy individuals was examined. NETs were quantitatively detected by absorption and fluorometric-based assays for the NET-specific proteins (NE, MPO) and cell-free DNA. Immunofluorescence microscopy images were used for visualization.

Results

Both surfactant preparations exerted a dose-dependent inhibitory effect on NET formation. Samples treated with higher concentrations and with 30 min pre-incubation prior to stimulation with phorbol-12-myristate-13-acetate had significantly lower levels of NET-specific proteins and cell-free DNA compared to untreated samples. Immunofluorescence microscopy confirmed these findings.

Conclusions

The described dose-dependent modulation of NET formation ex vivo suggests an interaction between exogenous surfactant supplementation and neutrophil granulocytes. The immunoregulatory effects of surfactant preparations should be considered for further examination of inflammatory diseases.

Improving lung aeration in ventilated newborn preterm rabbits with a partially aerated lung

Preterm newborns commonly receive intermittent positive pressure ventilation (iPPV) at birth, but the optimal approach that facilitates uniform lung aeration is unknown, particularly in a partially aerated lung. As both inflation time and exogenous surfactant facilitate uniform lung aeration, we investigated whether they can improve lung aeration and lung mechanics in a partially aerated lung immediately after birth. Preterm rabbit kittens (29 days of gestation, term ~32 days) were delivered by caesarean section and partial lung aeration was created by intubating and mechanically ventilating the right lung. The tube was then withdrawn to ventilate both lungs using inflation times of 0.2 s or 1.0 s, with or without exogenous surfactant (200 mg/kg; Curosurf) and a tidal volume (Vt) of 8 mL/kg. Simultaneous phase contrast X-ray imaging and plethysmography were used to measure lung aeration and mechanics. Kittens ventilated with longer inflation times (1.0 s) reached their target Vt with fewer inflations, required lower inflation pressures (28.5 ± 1.1 vs. 33.5 ± 1.3 cmH₂O, P = 0.01) and had higher dynamic lung compliances (0.54 ± 0.3 vs. 0.40 ± 0.3 cmH₂O·mL^-1·kg^-1, P = 0.003). Surfactant increased functional residual capacity (FRC; 31.9 ± 3.2 vs. 18.0 ± 3.9 mL/kg, P = 0.02) and the proportion of the Vt entering the previously unaerated lung but had no effect on dynamic lung compliance. Combining early surfactant treatment with longer inflation times increases FRC levels, improves dynamic lung compliance, reduces inflation pressures and markedly increases the proportion of the lungs being ventilated during iPPV in preterm kittens with a partially aerated lung.NEW & NOTEWORTHY Preterm newborns commonly receive intermittent positive pressure ventilation (iPPV) at birth, but the optimal approach that facilitates uniform lung aeration is unknown, particularly in a partially aerated lung. Using phase contrast X-ray imaging, we showed that combining a long inflation time (1.0 s) with surfactant improved lung mechanics and aeration in the immediate newborn period. The current clinical practice of using short inflation times during iPPV might be suboptimal and a different approach is needed.

Review demonstrates that less invasive surfactant administration in preterm neonates leads to fewer complications

Surfactant treatment of neonatal respiratory distress syndrome (RDS) was introduced in Europe during the 1990s. Meta-analyses have indicated that using less invasive surfactant administration techniques on preterm neonates receiving continuous positive airway pressure (CPAP) results in improved survival rates without bronchopulmonary dysplasia. Surfactant should be administered early and ventilator settings adapted to changing oxygen requirements and lung mechanics. Side effects including initial bradycardia, oxygen desaturation, tube obstruction and isolated cases of pulmonary haemorrhage have been reported.

CONCLUSION

Less invasive surfactant therapy improves pulmonary outcomes in preterm neonates with RDS and should ideally be administered in combination with CPAP.

Effects of bovine lipid extract surfactant administration in preterm infants treated for respiratory distress syndrome

AIM

To review the initial effectiveness of bovine lipid extract surfactant (BLES) for the treatment of respiratory distress syndrome in preterm infants.

METHODS AND RESULTS

A retrospective review of data collected from infants born <37-week gestation with respiratory distress syndrome treated with BLES between February 1, 2015 and March 1, 2016. Data were analyzed to determine the timing of initial dose, the length of time to wean the fraction of inspired oxygen (FiO2) concentration to 0.21 following initial dose, and the number of repeated doses given during hospital admission. Infants were subgrouped by gestational age stratum, 230 to 276 weeks (group 1), 280 to 316 weeks (group 2), and 320 to 366 weeks (group 3). Ninety-eight infants received the surfactant during the study period. After applying exclusion criteria, 77 infants were analyzed. Mean (SD) gestational age was 28 (4) weeks, and mean (SD) birth weight was 1250 (602) g. Initial dose of BLES was given at a median (interquartile range) time of 29 (19-43) minutes in group 1, 150 (20-615) minutes in group 2, and 990 (53-2025) minutes in group 3. Median (interquartile range) length of time to wean the FiO2 concentration to 0.21 was 14 (5-56) minutes, 10 (5-53) minutes, and 10 (5-38) minutes in groups 1, 2, and 3, respectively. Ten infants required repeated doses.

CONCLUSION

Given the rapid response of BLES in all the groups, careful monitoring of ventilator parameters is paramount to allow for rapid weaning and early extubation to avoid lung injury associated with mechanical ventilation.

In Vivo Evaluation of the Acute Pulmonary Response to Poractant Alfa and Bovactant Treatments in Lung-Lavaged Adult Rabbits and in Preterm Lambs with Respiratory Distress Syndrome

BACKGROUND

Poractant alfa (Curosurf^®) and Bovactant (Alveofact^®) are two animal-derived pulmonary surfactants preparations approved for the treatment of neonatal respiratory distress syndrome (nRDS). They differ in their source, composition, pharmaceutical form, and clinical dose. How much these differences affect the acute pulmonary response to treatment is unknown.

OBJECTIVES

Comparing these two surfactant preparations in two different animal models of respiratory distress focusing on the short-term response to treatment.

METHODS

Poractant alfa and Bovactant were administered in a 50-200 mg/kg dose range to surfactant-depleted adult rabbits with acute respiratory distress syndrome induced by lavage and to preterm lambs (127-129 days gestational age) with nRDS induced by developmental immaturity. The acute impact of surfactant therapy on gas exchange and pulmonary mechanics was assessed for 1 h in surfactant-depleted rabbits and for 3 h in preterm lambs.

RESULTS

Overall, treatment with Bovactant 50 mg/kg or Poractant alfa 50 mg/kg did not achieve full recovery of the rabbits' respiratory conditions, as indicated by significantly lower arterial oxygenation and carbon dioxide values. By contrast, the two approved doses for clinical use of Poractant alfa (100 and 200 mg/kg) achieved a rapid and sustained recovery in both animal models. The comparison of the ventilation indices of the licensed doses of Bovactant (50 mg/kg) and Poractant alfa (100 mg/kg) showed a superior performance of the latter preparation in both animal models. At equal phospholipid doses, Poractant alfa was superior to Bovactant in terms of arterial oxygenation in both animal models. In preterm lambs, surfactant replacement therapy with Poractant alfa at either 100 or 200 mg/kg was associated with significantly higher lung gas volumes compared to Bovactant treatment with 100 mg/kg.

CONCLUSION

At the licensed doses, the acute pulmonary response to Poractant alfa was significantly better than the one observed after Bovactant treatment, either at 50 or at 100 mg/kg dose, in two animal models of pulmonary failure.

Comparison of the Efficacy of Three Natural Surfactants (Curosurf, Survanta, and Alveofact) in the Treatment of Respiratory Distress Syndrome Among Neonates: A Randomized Controlled Trial

BACKGROUND

Although several different types of natural surfactants are available, including Alveofact, Curosurf, and Survanta, the preferred type and the magnitude of their effects are unknown.

OBJECTIVES

This study was designed to compare the effects of these three surfactants on the gas exchange and clinical outcomes of neonates with respiratory distress syndrome (RDS).

METHODS

This triple-blind randomized clinical trial studied all preterm neonates ≤ 37 weeks with RDS who were admitted to the neonatal intensive care unit (NICU) of Taleghani hospital (Tabriz, Iran) between 2012 and 2013. The patients were divided into three groups, each of which received one of these surfactants. The incidences of ventilator dependency, patent ductus arteriosus (PDA), broncho-pulmonary dysplasia (BPD), retinopathy of prematurity (ROP), intraventricular hemorrhage (IVH), hospital-stay length, and continuous positive airway pressure (CPAP) failure, as well as blood gas levels, were recorded as endpoint measurements and compared.

RESULTS

In total, 165 neonates of gestational age ≤ 37 weeks with RDS were examined. Neonates were allocated to three different groups randomly, including a Survanta group (n = 49), a Curosurf group (n = 62), and an Alveofact group (n = 54). The mean gestational age of the neonates was 31.6 ± 3.7 weeks, and their mean weight was 1,840 ± 790 grams. The male/female ratio was 2:1 (67% male, 33% female); 104 (63%) neonates were ≤ 32 weeks gestational age, and 61 (37%) were >32 weeks. There were no significant differences for gender or demographic characteristics among the neonates in relation to the type of applied surfactant. According to the clinical parameters (BPD, IVH, ROP, hospital-stay length, and mechanical ventilation requirement), no significant differences were observed between the groups before and after surfactant administration, but the differences between the Survanta and Alveofact groups for the incidence rates of pneumothorax (P = 0.03) and pulmonary hemorrhage (P = 0.03) were statistically significant.

CONCLUSIONS

No significant differences were observed in most of the clinical variables between the three types of natural surfactant, but in neonates ≤ 32 weeks, the incidence of pneumothorax was significantly higher in the Alveofact group; in neonates > 32 weeks, the incidences of PDA, mean hospital-stay length, and mean mechanical ventilation time were also significantly higher in the same group. It thus appears that Curosurf and Survanta replacement therapies among premature neonates with RDS perform better than Alveofact replacement therapy.

Comparison of animal-derived surfactants for the prevention and treatment of respiratory distress syndrome in preterm infants

BACKGROUND

Animal-derived surfactants have been shown to have several advantages over the first generation synthetic surfactants and are the most commonly used surfactant preparations. The animal-derived surfactants in clinical use are minced or lavaged and modified or purified from bovine or porcine lungs. It is unclear whether significant differences in clinical outcome exist among the available bovine (modified minced or lavage) and porcine (minced or lavage) surfactant extracts.

OBJECTIVES

To compare the effect of administration of different animal-derived surfactant extracts on the risk of mortality, chronic lung disease, and other morbidities associated with prematurity in preterm infants at risk for or having respiratory distress syndrome (RDS).

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 7), MEDLINE via PubMed (1966 to July 31, 2015), EMBASE (1980 to July 31, 2015), and CINAHL (1982 to July 31, 2015). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomized controlled trials and quasi-randomized trials.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials that compared the effect of animal-derived surfactant extract treatment administered to preterm infants at risk for or having RDS to prevent complications of prematurity and mortality.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes were excerpted from the reports of the clinical trials by the review authors. Subgroup analyses were performed based on gestational age, surfactant dosing and schedule, treatment severity and treatment strategy. Data analysis was performed in accordance with the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS

Sixteen randomized controlled trials were included in the analysis. Bovine lung lavage surfactant extract to modified bovine minced lung surfactant extract: Seven treatment studies and two prevention studies compared bovine lung lavage surfactant extract to modified bovine minced lung surfactant extract. The meta-analysis did not demonstrate any significant differences in death or chronic lung disease in the prevention trials (typical RR 1.02, 95% CI 0.89 to 1.17; typical RD 0.01, 95% CI -0.05 to 0.06; 2 studies and 1123 infants; high quality evidence) or treatment trials (typical RR 0.95, 95% CI 0.86 to 1.06; typical RD -0.02 , 95% CI -0.06 to 0.02; 3 studies and 2009 infants; high quality evidence) Modified bovine minced lung surfactant extract compared with porcine minced lung surfactant extract: Nine treatment studies compared modified bovine minced lung surfactant extract to porcine minced lung surfactant extract. Meta-analysis of these trials demonstrate a significant increase in the risk of mortality prior to hospital discharge (typical RR 1.44, 95% CI 1.04 to 2.00; typical RD 0.05, 95% CI 0.01 to 0.10; NNTH 20, 95% CI 10 to 100; 9 studies and 901 infants; moderate quality evidence), death or oxygen requirement at 36 weeks' postmenstrual age (typical RR 1.30, 95% CI 1.04 to 1.64; typical RD 0.11, 95% CI 0.02 to 0.20; NNTH 9, 95% CI 5 to 50; 3 studies and 448 infants; moderate quality evidence), receiving more than one dose of surfactant (typical RR 1.57, 95% CI 1.29 to 1.92; typical RD 0.14, 95% CI 0.08 to 0.20; NNTH 7, 95% CI 5 to 13; 6 studies and 786 infants), and patent ductus arteriosus (PDA) requiring treatment (typical RR 1.86, 95% CI 1.28 to 2.70; typical RD 0.28, 95% CI 0.13 to 0.43; NNTH 4, 95% CI 2 to 8; 3 studies and 137 infants) in infants treated with modified bovine minced lung surfactant extract compared with porcine minced lung surfactant extract. In the subgroup analysis based on initial dose of surfactant, improvement in mortality prior to discharge (typical RR 1.62, 95% CI 1.11 to 2.38; typical RD 0.06, 95% CI 0.01 to 0.11; NNTH 16, 95% CI 9 to 100) and risk of death or oxygen requirement at 36 weeks' postmenstrual age (typical RR 1.39, 95% CI 1.08 to 1.79; typical RD 0.13, 95% 0.03 to 0.23; NNTH 7, 95% CI 4 to 33) was limited to higher initial dose of porcine minced lung surfactant (> 100 mg/kg). Other comparisons: No difference in outcome was noted between bovine lung lavage surfactant extract versus porcine minced lung surfactant extract. There were no studies comparing bovine lung lavage surfactant extract versus porcine lung lavage surfactant; or porcine minced lung surfactant extract versus porcine lung lavage surfactant.

AUTHORS' CONCLUSIONS

Significant differences in clinical outcome were noted in the comparison trials of modified minced lung surfactant extract (beractant) compared with porcine minced lung surfactant extract (poractant alfa) including a significant increase in the risk of mortality prior to discharge, death or oxygen requirement at 36 weeks' postmenstrual age, PDA requiring treatment and "receiving > 1 dose of surfactant" in infants treated with modified bovine minced lung surfactant extract compared with porcine minced lung surfactant extract. The difference in these outcomes was limited to studies using a higher initial dose of porcine minced lung surfactant extract. It is uncertain whether the observed differences are from differences in dose or from source of extraction (porcine vs. bovine) because of the lack of dose-equivalent comparison groups with appropriate sample size. No differences in clinical outcomes were observed in comparative trials between bovine lung lavage surfactant and modified bovine minced lung surfactants.

A comparison of conventional surfactant treatment and partial liquid ventilation on the lung volume of injured ventilated small lungs

As an alternative to surfactant therapy (ST), partial liquid ventilation (PLV) with perfluorocarbons (PFC) has been considered as a treatment for acute lung injury (ALI) in newborns. The instilled PFC is much heavier than the instilled surfactant and the aim of this study was to investigate whether PLV, compared to ST, increases the end-expiratory volume of the lung (VL). Fifteen newborn piglets (age <12 h, mean weight 678 g) underwent saline lung lavage to achieve a surfactant depletion. Thereafter animals were randomized to PLV (n = 8), receiving PFC PF5080 (3M, Germany) at 30 mL kg(-1), and ST (n = 7) receiving 120 mg Curosurf®. Blood gases, hemodynamics and static compliance were measured initially (baseline), immediately after ALI, and after 240 min mechanical ventilation with either technique. Subsequently all piglets were killed; the lungs were removed in toto and frozen in liquid N2. After freeze-drying the lungs were cut into lung cubes (LCs) with edge lengths of 0.7 cm, to calculate VL. All LCs were weighed and the density of the dried lung tissue was calculated. No statistically significant differences between treatment groups PLV and ST (means ± SD) were noted in body weight (676 ± 16 g versus 679 ± 17 g; P = 0.974) or lung dry weight (1.64 ± 0.29 g versus 1.79 ± 0.48 g; P = 0.48). Oxygenation index and ventilatory efficacy index did not differ significantly between both groups at any time. VL (34.28 ± 6.13 mL versus 26.22 ± 8.1 mL; P < 0.05) and the density of the dried lung tissue (48.07 ± 5.02 mg mL(-1) versus 69.07 ± 5.30 mg mL(-1); P < 0.001), however, differed significantly between the PLV and ST groups. A 4 h PLV treatment of injured ventilated small lungs increased VL by 30% and decreased lung density by 31% compared to ST treatment, indicating greater lung distension after PLV compared to ST.

Severe airway obstruction during surfactant administration using a standardized protocol: a prospective, observational study

OBJECTIVE

The objective of this study was to evaluate the occurrence of adverse effects during surfactant delivery, using a standardized protocol for administration and management of complications.

STUDY DESIGN

The protocol was developed, implemented and used for 6 months. Vital signs and ventilatory parameters were prospectively recorded during the procedure. Infants were classified into three groups, based on the occurrence and severity of complications: no, minor or major.

RESULT

A total of 39 infants received surfactant and 19 presented some complication: 11 minor and 8 major. Six of the major complications were episodes of severe airway obstruction (SAO) and five occurred in extreme low birth weight (ELBW) infants that had more severe lung disease before surfactant delivery. Two cases of persistent pulmonary hypertension occurred in infants with birth weight>1000  g.

CONCLUSION

This study identified a high rate of SAO and provides data to support changes in the protocol, which should include faster and more robust increases in positive inspiratory pressures in ELBW infants presenting with SAO.

Effect of exogenous surfactants on viability and DNA synthesis in A549, immortalized mouse type II and isolated rat alveolar type II cells

Background

In mechanically ventilated preterm infants with respiratory distress syndrome (RDS), exogenous surfactant application has been demonstrated both to decrease DNA-synthesis but also and paradoxically to increase epithelial cell proliferation. However, the effect of exogenous surfactant has not been studied directly on alveolar type II cells (ATII cells), a key cell type responsible for alveolar function and repair.

Objective

The aim of this study was to investigate the effects of two commercially available surfactant preparations on ATII cell viability and DNA synthesis.

Methods

Curosurf^® and Alveofact^® were applied to two ATII cell lines (human A549 and mouse iMATII cells) and to primary rat ATII cells for periods of up to 24 h. Cell viability was measured using the redox indicator resazurin and DNA synthesis was measured using BrdU incorporation.

Results

Curosurf^® resulted in slightly decreased cell viability in all cell culture models. However, DNA synthesis was increased in A549 and rat ATII cells but decreased in iMATII cells. Alveofact^® exhibited the opposite effects on A549 cells and had very mild effects on the other two cell models.

Conclusion

This study showed that commercially available exogenous surfactants used to treat preterm infants with RDS can have profound effects on cell viability and DNA synthesis.