PURPOSE: Pulmonary surfactants for preterm infants contain mostly animal-derived surfactant proteins (SPs), which are essential for lowering surface tension. We prepared artificial pulmonary surfactants using synthetic human SP analogs and performed in vitro and in vivo experiments. MATERIALS AND METHODS: We synthesized peptide analogues that resemble human SP-B (RMLPQLVCRLVLRCSMD) and SP-C (CPVHLKRLLLLLLLLLLLLLLLL). Dipalmitoylphosphatidylcholine (DPPC), phosphatidylglycerol (PG), and palmitic acid (PA) were added and mixed in lyophilized to render powdered surfactant. Synsurf-1 was composed of DPPC:PG:PA:SP-B (75:25:10:3, w/w); Synsurf-2 was composed of DPPC:PG:PA:SP-C (75:25:10:3, w/w); and Synsurf-3 was composed of DPPC:PG:PA:SP-B:SP-C (75:25:10:3:3, w/w). We performed in vitro study to compare the physical characteristics using pulsating bubble surfactometer and modified Wilhelmy balance test. Surface spreading and adsorption test of the surfactant preparations were measured. In vivo test was performed using term and preterm rabbit pups. Pressure-volume curves were generated during the deflation phase. Histologic findings were examined. RESULTS: Pulsating bubble surfactometer readings revealed following minimum and maximum surface tension (mN/m) at 5 minutes: Surfacten® (5.5±0.4, 32.8±1.6), Synsurf-1 (16.7±0.6, 28.7±1.5), Synsurf-2 (7.9±1.0, 33.1±1.6), and Synsurf-3 (7.1±0.8, 34.5±1.0). Surface spreading rates were as follows: Surfacten® (27 mN/m), Synsurf-1 (43 mN/m), Synsurf-2 (27 mN/m), and Synsurf-3 (27 mN/m). Surface adsorption rate results were as follows: Surfacten® (28 mN/m), Synsurf-1 (35 mN/m), Synsurf-2 (29 mN/m), and Synsurf-3 (27 mN/m). The deflation curves were best for Synsurf-3; those for Synsurf-2 were better than those for Surfacten®. Synsurf-1 was the worst surfactant preparation. Microscopic examination showed the largest aerated area of the alveoli in the Synsurf-3 group, followed by Synsurf-1 and Surfacten®; Synsurf-2 was the smallest. CONCLUSION: Synsurf-3 containing both SP-B and SP-C synthetic analogs showed comparable and better efficacy than commercially used Surfacten® in lowering surface tension, pressure-volume curves, and tissue aerated area of the alveoli.
1,2-Dipalmitoylphosphatidylcholine ; Adsorption ; Animal Experimentation* ; Animals* ; Humans ; In Vitro Techniques* ; Infant, Newborn ; Infant, Premature ; Palmitic Acid ; Pulmonary Surfactant-Associated Proteins ; Pulmonary Surfactants ; Reading ; Surface Tension

Pulmonary surfactant (PS) is synthesized and secreted by alveolar epithelial type II (AEII) cells, which is a complex compound formed by proteins and lipids. Surfactant participates in a range of physiological processes such as reducing the surface tension, keeping the balance of alveolar fluid, maintaining normal alveolar morphology and conducting host defense. Genetic disorders of the surfactant homeostasis genes may result in lack of surfactant or cytotoxicity, and lead to multiple lung diseases in neonates, children and adults, including neonatal respiratory distress syndrome, interstitial pneumonia, pulmonary alveolar proteinosis, and pulmonary fibrosis. This paper has provided a review for the functions and processes of pulmonary surfactant metabolism, as well as the connection between disorders of surfactant homeostasis genes and lung diseases.
ATP-Binding Cassette Transporters ; genetics ; DNA-Binding Proteins ; genetics ; Homeostasis ; Humans ; Lung Diseases ; genetics ; Pulmonary Surfactant-Associated Protein C ; genetics ; Pulmonary Surfactants ; metabolism ; Transcription Factors

ATP-Binding Cassette Transporters ; genetics ; DNA Mutational Analysis ; Humans ; Infant ; Lung ; pathology ; physiopathology ; Lung Diseases, Interstitial ; diagnosis ; genetics ; pathology ; Mutation ; genetics ; Pulmonary Alveoli ; pathology ; Pulmonary Surfactant-Associated Proteins ; deficiency ; genetics

Respiratory distress syndrome (RDS) among preterm infants is typically due to a quantitative deficiency of pulmonary surfactant. Aside from the degree of prematurity, diverse environmental and genetic factors can affect the development of RDS. The variance of the risk of RDS in various races/ethnicities or monozygotic/dizygotic twins has suggested genetic influences on this disorder. So far, several specific mutations in genes encoding surfactant-associated molecules have confirmed this. Specific genetic variants contributing to the regulation of pulmonary development, its structure and function, or the inflammatory response could be candidate risk factors for the development of RDS. This review summarizes the background that suggests the genetic predisposition of RDS, the identified mutations, and candidate genetic polymorphisms of pulmonary surfactant proteins associated with RDS.
Genetic Predisposition to Disease ; Humans ; Infant, Newborn ; Infant, Premature ; Polymorphism, Genetic ; Pulmonary Surfactant-Associated Proteins ; Pulmonary Surfactants ; Risk Factors* ; Twins

ATP-Binding Cassette Transporters ; genetics ; metabolism ; Animals ; Biological Transport ; Child ; DNA Mutational Analysis ; Humans ; Hypertension, Pulmonary ; genetics ; metabolism ; Lung Diseases, Interstitial ; genetics ; metabolism ; Molecular Sequence Data ; Mutation ; Polymerase Chain Reaction ; Protein Conformation ; Pulmonary Surfactant-Associated Proteins ; genetics ; metabolism ; Respiratory Distress Syndrome, Newborn ; genetics ; metabolism

OBJECTIVETo investigate the change of lung surfactant protein (SP) A,B,C,D of rats following silica dust exposure in order to provide the evidences for the early diagnosis indices or therapy of silicosis.

METHODS60 male SD rats were randomly divided into silica group, and corresponding controls group. Rats in silica group were administrated 1 ml silica solution by intratracheal instillation at dose of 50 mg/ml. Rats in control group were administrated the same amount saline. At 3rd, 7th, 14th, 21st, 28th after silica exposure, serum and bronchoalveolar lavage fluid (BALF) samples were obtained. The concentration of SP-A, SP-B, SP-C, SP-D in serum and BALF were measured by using enzyme immunoassay (ELISA). Meanwhile the levels of total anti-oxidative activity (T-AOC) and hydroxyproline (HYP) in lung tissue were also detected. The pathology of lung tissue was conducted.

RESULTSCompared with control group, SP-A concentration in BALF of silica exposed rat for 3, 14, 21, 28d was significant lower and SP-D concentration in BALF of silica exposed rat for all time points was also lower. The differences were significant (P < 0.05). Meanwhile SP-B level in 7, 14, 21, 28 d silica exposed rats BALF and SP-C level in 14, 21, 28 d silica exposed rats markedly decreased (P < 0.05). In addition compared with control group, SP-A, SP-B and SP-C concentration in serum of silica exposed rat were higher when SP-A for 14, 21, 28 d silica exposure, SP-B for 7, 14, 21 d silica exposure and Sp-C for 7, 14, 21, 28 d exposure. And all difference were significant (P < 0.05). As silica exposure time increased, SP-C concentration in serum showed an increase trend, which showed a time-response relationship (r = 0.618, P = 0.042). However, SP-D concentration in serum of rat for 7, 14, 21, 28d silica exposure were significant lower than that of control group (P < 0.005). And there was a decrease trend with time point exposure regarding of SP-D (r = -0.731, P = 0.016). The HYP content in lung tissue of experiment rats increased at 3rd, 7th, 14th, 21st and 28th day time point and The T-AOC activity in lung tissue decrease at, 7th, 14th, 21st and 28th day time point. The differences were significant (P < 0.05). There was a positive correlation (P = 0.803, P = 0.045) between SP-C in BALF and HYP of silica exposed rats and a negative correlation between SP-D in BALF and HYP (r = -0.867, P = 0.033). No significant correlation were seen between SP-A, SP-B BALF and HYP (y = 0.416, P = 0.28; r = 0.592, P = 0.071). SP-C concentration in BALF and serum all showed an increased trend and a positive correlation was seen (r = 0.539, P = 0.046). The same decrease trend was seen between SP-D in BALF and serum and correlation value was 0.870 (P = 0.034).

CONCLUSIONThe silica exposure did cause the change of SP content both in BALF and serum. The SP-C and SP-D content in serum might be served as an early effective biomarker of silicosis.

Animals ; Bronchoalveolar Lavage Fluid ; Male ; Pulmonary Fibrosis ; metabolism ; pathology ; Pulmonary Surfactant-Associated Proteins ; metabolism ; Rats ; Rats, Sprague-Dawley ; Silicon Dioxide ; Silicosis ; metabolism ; pathology

OBJECTIVETo explore the prevalence of pulmonary surfactant associated pathway genes functional variants in Chinese population.

METHODUsing a cohort of 258 mixed ethnic population of Han and Zhuang, we pooled DNA samples from 146 term male infants and 112 term female infants and then used an Ill umina next generation sequencing platform to perform the complete exonic resequencing in 6 target genes:surfactant protein-B (SFTPB), surfactant protein-C (SFTPC), ATP-binding cassette transporter A3 (ABCA3), lysophospholipid acyltransferase 1 (LPCAT1), choline phosphotransferase 1 (CHPT1), phosphate cytidylyltransferase 1, choline, beta (PCYT1B). Collapsing methods was used to determine the functional allele frequency.

RESULT(1) Altogether, 128 variants were found, including 44 synonymous variants, 66 nonsynonymous variants and 18 insertions-deletions. Of these, 28 variants were predicted to alter protein function. Two of these variants were seen twice, the rest variants were only seen once, for a total of 30 functional alleles; (2) ABCA3 had the most functional variants in both male and female groups with the minor allele frequencies of 0.014 (1.4%) and 0.04 (4%), respectively. The total functional allele frequencies of 6 genes were 0.041 (4.1%) and 0.08 (8%) in the two groups, respectively (P = 0.06).

CONCLUSION(1) Functional variants in pulmonary surfactant associated pathway genes are present in the mixed Han-Zhuang population. (2) ABCA3 contained the most functional variants suggesting that ABCA3 could contribute significantly to neonatal respiratory distress syndrome and other lung disease.

1-Acylglycerophosphocholine O-Acyltransferase ; genetics ; metabolism ; ATP-Binding Cassette Transporters ; genetics ; Asian Continental Ancestry Group ; ethnology ; genetics ; China ; ethnology ; Female ; Gene Frequency ; Genetic Association Studies ; Genetic Predisposition to Disease ; Genetic Variation ; Genotype ; Humans ; Infant, Newborn ; Male ; Pulmonary Surfactant-Associated Protein C ; genetics ; Pulmonary Surfactant-Associated Proteins ; genetics ; Respiratory Distress Syndrome, Newborn ; ethnology ; genetics

Dendritic-cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN; CD209) has an important role in mediating adherence of Mycobacteria species, including M. tuberculosis and M. bovis BCG to human dendritic cells and macrophages, in which these bacteria can survive intracellularly. DC-SIGN is a C-type lectin, and interactions with mycobacterial cells are believed to occur via mannosylated structures on the mycobacterial surface. Recent studies suggest more varied modes of binding to multiple mycobacterial ligands. Here we identify, by affinity chromatography and mass-spectrometry, four novel ligands of M. bovis BCG that bind to DC-SIGN. The novel ligands are chaperone protein DnaK, 60 kDa chaperonin-1 (Cpn60.1), glyceraldehyde-3 phosphate dehydrogenase (GAPDH) and lipoprotein lprG. Other published work strongly suggests that these are on the cell surface. Of these ligands, lprG appears to bind DC-SIGN via typical proteinglycan interactions, but DnaK and Cpn60.1 binding do not show evidence of carbohydrate-dependent interactions. LprG was also identified as a ligand for DC-SIGNR (L-SIGN; CD299) and the M. tuberculosis orthologue of lprG has been found previously to interact with human toll-like receptor 2. Collectively, these findings offer new targets for combating mycobacterial adhesion and within-host survival, and reinforce the role of DCSIGN as an important host ligand in mycobacterial infection.
Amino Acid Sequence ; Bacterial Adhesion ; physiology ; Bacterial Proteins ; genetics ; metabolism ; Cell Adhesion Molecules ; genetics ; metabolism ; Chromatography, Affinity ; Dendritic Cells ; metabolism ; microbiology ; Host-Pathogen Interactions ; genetics ; physiology ; Humans ; In Vitro Techniques ; Lectins, C-Type ; genetics ; metabolism ; Ligands ; Macrophages ; metabolism ; microbiology ; Mass Spectrometry ; Membrane Proteins ; genetics ; metabolism ; Models, Biological ; Molecular Chaperones ; genetics ; metabolism ; Molecular Sequence Data ; Mycobacterium bovis ; genetics ; metabolism ; Mycobacterium tuberculosis ; genetics ; metabolism ; pathogenicity ; Pulmonary Surfactant-Associated Protein A ; metabolism ; Receptors, Cell Surface ; genetics ; metabolism

OBJECTIVEAlveolar epithelium impairment is one of pathological changes associated with chronic lung disease (CLD). Hoxb5 is one of the few homeobox genes strongly expressed in the developing lung. This study investigated the expression of HoxB5, SPC and AQP5 in rats with CLD in order to explore the role of Hoxb-5 in impairment and reparation of alveolar epithelium.

METHODSEighty neonatal rats were randomly exposed to hyperoxia (model group) or to room air (control group) (n=40 each). The CLD model was induced by hyperoxia exposure. The expression of HoxB5, SPC and AQP5 protein and mRNA in the lung tissue was detected by immunohistochemistry and RT-PCR 1, 3, 7, 14 and 21 days after exposure.

RESULTSIn the model group HoxB5 expression significantly decreased 7, 14 and 21 days after hyperoxia exposure. SPC expression decreased 3 days after hyperoxia exposure but increased significantly 7, 14 and 21 days after hyperoxia exposure as compared to the control group. AQP5 expression was progressively reduced with prolonged hyperoxia exposure.

CONCLUSIONSHyperoxia exposure may lead to alveolar epithelial cell (AEC) damage in neonatal rats. The increased SPC expression and decreased AQP5 expression suggested that the ability of differentiation and transformation of AECII into AECI decreased in neonatal rats with CLD. The decreased HoxB5 expression following hyperoxia exposure might contribute to a decreased ability of differentiation of AECII.

Animals ; Animals, Newborn ; Aquaporin 5 ; analysis ; genetics ; Chronic Disease ; Female ; Homeodomain Proteins ; analysis ; genetics ; Hyperoxia ; complications ; Immunohistochemistry ; Lung ; pathology ; Lung Diseases ; etiology ; metabolism ; Male ; Pulmonary Surfactant-Associated Protein C ; analysis ; genetics ; RNA, Messenger ; analysis ; Rats ; Rats, Wistar ; Reverse Transcriptase Polymerase Chain Reaction

Inhalation injury is a major contributor to the morbidity and mortality associated with serious burns. The improvement in the understanding of smoke inhalation injury had been obtained in the last half century in China. The models of steam and smoke inhalation injury had been reproduced and a series of experimental studies had been performed. It was found that chemical bronchiotracheitis, pulmonary edema and alveolar collapse (atelectasis) were the primary pathologic findings after inhalation injury. The second inflammatory response would play an important role in the development of acute respiratory failure. The roles of some cytokines, inflammatory cells and pulmonary surfactants in the development of inhalation injury had been elucidated. The etiologic factors and the pathophysiologic changes in inhalation injury had been illustrated clearly. These basic science investigations had led to the advances in protective strategies for the complications of inhalation injury. Now the morbidity and mortality of inhalation injury have decreased markedly in China.
Burns, Inhalation ; etiology ; therapy ; China ; High-Frequency Ventilation ; Humans ; Pulmonary Surfactant-Associated Proteins ; Smoke Inhalation Injury ; etiology ; therapy