Association of SP-C gene codon 186 polymorphism (rs1124) and risk of RDS

RDS-NExT workshop: consensus statements for the use of surfactant in preterm neonates with RDS

OBJECTIVE

To provide the best clinical practice guidance for surfactant use in preterm neonates with respiratory distress syndrome (RDS). The RDS-Neonatal Expert Taskforce (RDS-NExT) initiative was intended to add to existing evidence and clinical guidelines, where evidence is lacking, with input from an expert panel.

STUDY DESIGN

An expert panel of healthcare providers specializing in neonatal intensive care was convened and administered a survey questionnaire, followed by 3 virtual workshops. A modified Delphi method was used to obtain consensus around topics in surfactant use in neonatal RDS.

RESULT

Statements focused on establishing RDS diagnosis and indicators for surfactant administration, surfactant administration methods and techniques, and other considerations. After discussion and voting, consensus was achieved on 20 statements.

CONCLUSION

These consensus statements provide practical guidance for surfactant administration in preterm neonates with RDS, with a goal to contribute to improving the care of neonates and providing a stimulus for further investigation to bridge existing knowledge gaps.

Risk factors for respiratory assistance in premature infants

Premature infants are prone to dyspnea after birth due to immature development, and some infants require respiratory assistance. However, the risk factors for respiratory assistance in premature infants are rarely reported. The present study enrolled 3,394 premature infants (665 infants had been provided with respiratory assistance and 2,729 had not used respiratory assistance) to retrospectively analyze the risk factors associated with respiratory aid. The multivariate logistic regression analysis demonstrated that placental abnormality [odds ratio (OR)=1.284; P=0.048], the male sex (OR=0.696; P=0.001), delivery via cesarean section (OR=1.538; P<0.001), low 1-min Apgar score (OR=0.727; P<0.001), low birth weight (OR=0.999; P=0.005) and low gestational age (OR=0.616; P<0.001) were independent risk factors for respiratory assistance in premature infants. Overall, a number of risk factors, including placental abnormality, cesarean section, low 1-min Apgar score, low birth weight and small gestational age, were identified for respiratory assistance in premature infants. By conducting a risk assessment of risk factors at birth and using this information to provide timely respiratory assistance, the survival rates of premature infants may increase.

Single Nucleotide Polymorphisms Interactions of the Surfactant Protein Genes Associated With Respiratory Distress Syndrome Susceptibility in Preterm Infants

Background: Neonatal respiratory distress syndrome (RDS), due to surfactant deficiency in preterm infants, is the most common cause of respiratory morbidity. The surfactant proteins (SFTP) genetic variants have been well-studied in association with RDS; however, the impact of SNP-SNP (single nucleotide polymorphism) interactions on RDS has not been addressed. Therefore, this study utilizes a newer statistical model to determine the association of SFTP single SNP model and SNP-SNP interactions in a two and a three SNP interaction model with RDS susceptibility. Methods: This study used available genotype and clinical data in the Floros biobank at Penn State University. The patients consisted of 848 preterm infants, born <36 weeks of gestation, with 477 infants with RDS and 458 infants without RDS. Seventeen well-studied SFTPA1, SFTPA2, SFTPB, SFTPC, and SFTPD SNPs were investigated. Wang's statistical model was employed to test and identify significant associations in a case-control study. Results: Only the rs17886395 (C allele) of the SFTPA2 was associated with protection for RDS in a single-SNP model (Odd's Ratio 0.16, 95% CI 0.06-0.43, adjusted p = 0.03). The highest number of interactions (n = 27) in the three SNP interactions were among SFTPA1 and SFTPA2. The three SNP models showed intergenic and intragenic interactions among all SFTP SNPs except SFTPC. Conclusion: The single SNP model and SNP interactions using the two and three SNP interactions models identified SFTP-SNP associations with RDS. However, the large number of significant associations containing SFTPA1 and/or SFTPA2 SNPs point to the importance of SFTPA1 and SFTPA2 in RDS susceptibility.

Association analysis of the surfactant protein-C gene to childhood asthma

OBJECTIVES

This study aims to describe the molecular variability in the SFTPC gene in a childhood chronic respiratory disease, asthma, in the Tunisian population and to identify the implications based on a case-control study of p.Thr138Asn (T138N) and p.Ser186Asn (S186N) variants.

METHODS

We used direct sequencing for the genotyping of the SFTPC gene within 101 asthmatic children. The study of T138N and S186N variants in 110 controls is conducted by the PCR-RFLP technique.

RESULTS

The molecular study revealed 26 variants including 24 intronic variations and 2 exonic variations (T138N and S186N) with respective frequencies of 16.8% and 18.3%. We conducted a case-control study of the two identified exonic variations. A different genotypic and allelic distribution between the two groups was noted. Only the T138N polymorphism showed a significant association with asthma disease (p < 1 0 ^-3). Statistical analysis elaborated four haplotypes with the following frequencies in patients vs controls: 138Thr-186Ser (79.5% vs 57.6%), 138Thr-186Asn (3.7% vs 7.8%), 138Asn-186Thr (2.2% vs 20.2%) and 138Asn-186Asn (14.6% vs 14.4%). A significant difference (p < 1 0 ^-3) was highlighted in haplotype distribution. The 138Asn-186Ser (OR [95%CI] = 0.14[0.04-0.54], p = 0.004, R²=0.93) and 138Thr-186Asn (OR [95%CI] = 0.35[0.12-0.54], p = 0.047, R²=0.88) haplotypes showed a negative association with asthma which may constitute a protective factor against the disease.

CONCLUSION

In Tunisia, this work constitutes the first report interested in the SFTPC gene and highlights the genetic variability of the SFTPC gene in asthma. Therefore, the case-controls analysis may be useful in the study of surfactant proteins dysfunction in chronic respiratory disease at an early age.

SFTPC genetic polymorphisms are associated with tuberculosis susceptibility and clinical phenotype in a Western Chinese Han population

Tuberculosis (TB) is one of the most common infectious diseases globally. The surfactant protein C (SFTPC), which is involved in innate immunity and surfactant function in the lung, may contribute toward the progression of TB. The aim of the present study was to preliminarily investigate the possible association of single nucleotide polymorphisms (SNPs) in the SFTPC gene with TB susceptibility and clinical phenotypes in a Western Chinese Han population. The improved multiplex ligation detection reaction method was used to genotype 6 SNPs in SFTPC, in 900 patients with TB and 1,534 healthy control subjects. It was found that the A allele for rs1124 and the C allele for rs8192313 were associated with increased susceptibility to TB, P=0.024 and P=0.045, respectively. However, these two P-values were not significant following Bonferroni correction. In all samples, the haplotype [CGA], representing three SFTPC variants, was revealed to increase the risk of TB (P=0.001 and P=0.005, following Bonferroni correction). Furthermore, patients with the AA genotype for rs1124 and with the CC genotype for rs8192313 were associated with higher levels of C-reactive protein (P=0.001 and P=0.005, respectively). The results of the present study indicated that the SFTPC SNPs may increase the susceptibility to TB and the immune response of the host to Mycobacterium tuberculosis and may potentially be novel biomarkers for the pathogenesis of TB.

Genetic Polymorphisms of LPCAT1, CHPT1 and PCYT1B and Risk of Neonatal Respiratory Distress Syndrome among a Chinese Han Population

BACKGROUND

The study of genetic polymorphisms of surfactant-lipids related genes can help to understand individual variability in the susceptibility to development of pulmonary pathologies. The purpose of this study was to evaluate the association of polymorphisms of surfactant-lipids related genes (LPCAT1, CHPT1 and PCYT1B) with the risk/severity of respiratory distress syndrome (RDS) in preterm neonates among the Chinese Han population in Southern China.

METHODS

Four hundred and forty-six preterm neonates were enrolled in a case-control study. Six polymorphisms of 3 genes were analyzed by PCR amplification of genomic DNA and genotyping was performed using an improved multiplex ligation detection reaction (iMLDR) technique based on LDR.

RESULTS

The GG genotype and G allele of LPCAT1-rs9728 were found less frequently in the RDS group than in the controls (11.5% vs. 22.0% and 38.3% vs. 48.2%, respectively) (p < 0.05).

CONCLUSION

This report is the first study to evaluate a direct genetic association between polymorphisms of LPCAT1 and RDS development in Chinese Han preterm infants. Our study raises the possibility that a genetic variation of LPCAT1 could be implicated in the pathophysiology of RDS in preterm neonates. GG genotype and G allele of rs9728 are protective factors for the development of RDS in preterm infants.

Genetic Association of Pulmonary Surfactant Protein Genes, SFTPA1, SFTPA2, SFTPB, SFTPC, and SFTPD With Cystic Fibrosis

Surfactant proteins (SP) are involved in surfactant function and innate immunity in the human lung. Both lung function and innate immunity are altered in CF, and altered SP levels and genetic association are observed in Cystic Fibrosis (CF). We hypothesized that single nucleotide polymorphisms (SNPs) within the SP genes associate with CF or severity subgroups, either through single SNP or via SNP-SNP interactions between two SNPs of a given gene (intragenic) and/or between two genes (intergenic). We genotyped a total of 17 SP SNPs from 72 case-trio pedigree (SFTPA1 (5), SFTPA2 (4), SFTPB (4), SFTPC (2), and SFTPD (2)), and identified SP SNP associations by applying quantitative genetic principles. The results showed (a) Two SNPs, SFTPB rs7316 (p = 0.0083) and SFTPC rs1124 (p = 0.0154), each associated with CF. (b) Three intragenic SNP-SNP interactions, SFTPB (rs2077079, rs3024798), and SFTPA1 (rs1136451, rs1059057 and rs4253527), associated with CF. (c) A total of 34 intergenic SNP-SNP interactions among the 4 SP genes to be associated with CF. (d) No SNP-SNP interaction was observed between SFTPA1 or SFTPA2 and SFTPD. (e) Equal number of SNP-SNP interactions were observed between SFTPB and SFTPA1/SFTPA2 (n = 7) and SP-B and SFTPD (n = 7). (f) SFTPC exhibited significant SNP-SNP interactions with SFTPA1/SFTPA2 (n = 11), SFTPB (n = 4) and SFTPD (n = 3). (g) A single SFTPB SNP was associated with mild CF after Bonferroni correction, and several intergenic interactions that are associated (p < 0.01) with either mild or moderate/severe CF were observed. These collectively indicate that complex SNP-SNP interactions of the SP genes may contribute to the pulmonary disease in CF patients. We speculate that SPs may serve as modifiers for the varied progression of pulmonary disease in CF and/or its severity.

Association of SP-B gene 9306 A/G polymorphism (rs7316) and risk of RDS

BACKGROUND

Respiratory distress syndrome (RDS) is a severe pulmonary disease predominantly affects preterm newborns. Polymorphisms of surfactant-protein genes have been mostly evaluated as the candidate contributors in genetics of RDS. However the results are divers in different studies. We aimed at investigating the association of surfactant protein B (SPB) gene 9306 A/G polymorphism (rs7316) with RDS development.

METHOD

Three hundred and eighty newborns with gestational age of less than 34 weeks were included in a multicenter case-control study. Respiratory distress (RD) was scored according to Downes' scoring system. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used for genotyping.

RESULT

One hundred and eighty-four neonates showed RDS and 196 did not. Gestational age (GA) was significantly lower in the RDS group compared with the controls. AA genotype and A allele were found more frequently in the RDS group than the controls (96.2% versus 63.8% and 98.1% versus 80.6%, respectively) (p =.0001).

CONCLUSIONS

This is the first report of association of SFTPB rs7316 polymorphism with RDS development in Iranian newborns. The current study suggests that GA <28-weeks is the most important factor in predisposition to RDS. Genetic background in terms of SP-B gene might be involved in predisposition to RDS in premature neonates.