1 Department of Otorhinolaryngology-Head and Neck Surgery, Konkuk University College of Medicine, Seoul; and 2 Department of Otorhinolaryngology, 3 The Airway Mucus Institute, 4 Brain Korea 21 ...Project for Medical Science, 5 Biomolecule Secretion Research Center, Yonsei University College of Medicine, Seoul, Korea
Submitted 25 April 2006
; accepted in final form 1 December 2006
Surfactant proteins (SPs), designated SP-A, SP-B, SP-C, and SP-D, play an important role in surfactant metabolism and host defense mechanisms in the lung. This study investigates expression of the different SP types in human nasal mucosa and cultured normal human nasal epithelial (NHNE) cells and whether the expression of SP mRNA is influenced by the degree of mucociliary differentiation. RT-PCR was performed with mRNA from cultured NHNE cells and nasal mucosa. Immunohistochemical staining for SPs was performed on nasal mucosa specimens. Western blot analysis was performed on cell lysates from cultured NHNE cells. SP-A2, SP-B, and SP-D mRNAs were expressed in normal NHNE cells and human nasal mucosa. SPs were localized in ciliated cells of the surface epithelium and serous acini of the submucosal glands. SP-A, SP-B, and SP-D proteins were expressed in cultured NHNE cells. The degree of mucociliary differentiation influenced expression of the SP gene. We demonstrate that SP-A, SP-B, and SP-D are expressed in human nasal mucosa and cultured NHNE cells. Further study of the functional role of SPs in the upper airway is required.
surfactant proteins A, B, and D
Address for reprint requests and other correspondence: J.-H. Yoon, Dept. of Otorhinolaryngology, Yonsei Univ. College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul, Korea 120-752 (e-mail: jhyoon{at}yumc.yonsei.ac.kr )
Pulmonary surfactant is essential for lung function. It is assembled, stored and secreted as particulate entities (lamellar body-like particles; LBPs). LBPs disintegrate when they contact an ...air-liquid interface, leading to an instantaneous spreading of material and a decline in surface tension. Here, we demonstrate that the film formed by the adsorbed material spontaneously segregate into distinct ordered and disordered lipid phase regions under unprecedented near-physiological conditions and, unlike natural surfactant purified from bronchoalveolar lavages, dynamically reorganized into highly viscous multilayer domains with complex three-dimensional topographies. Multilayer domains, in coexistence with liquid phases, showed a progressive stiffening and finally solidification, probably driven by a self-driven disassembly of LBPs from a sub-surface compartment. We conclude that surface film formation from LBPs is a highly dynamic and complex process, leading to a more elaborated scenario than that observed and predicted by models using reconstituted, lavaged, or fractionated preparations.
The efficacy of antenatal steroids for fetal lung maturation in the periviable period is not fully understood.
We sought to determine the lung maturational effects of antenatal steroids and ...inflammation in early gestation sheep fetuses, similar to the periviable period in human beings.
Date-mated ewes with singleton fetuses were randomly assigned to 1 of 4 treatment groups (n = 8/group): (1) maternal intramuscular injection of betamethasone; (2) intraamniotic lipopolysaccharide; (3) betamethasone + lipopolysaccharide; and (4) intraamniotic + intramuscular saline (controls). Fetuses were delivered surgically 48 hours later at 94 days’ gestation (63% term gestation) for comprehensive evaluations of lung maturation, and lung and systemic inflammation.
Relative to controls, first, betamethasone increased the fetal lung air space to mesenchymal area ratio by 47% but did not increase the messenger RNAs for the surfactant proteins-B and -C that are important for surfactant function or increase the expression of pro-surfactant protein-C in the alveolar type II cells. Second, betamethasone increased expression of 1 of the 4 genes in surfactant lipid synthetic pathways. Third, betamethasone increased genes involved in epithelium sodium channel transport, but not sodium-potassium adenosine triphosphatase or Aquaporin 5. Fourth, lipopolysaccharide increased proinflammatory genes in the lung but did not effectively recruit activated inflammatory cells. Last, betamethasone incompletely suppressed lipopolysaccharide-induced lung inflammation. In the liver, betamethasone when given alone increased the expression of serum amyloid A3 and C-reactive protein messenger RNAs.
Compared the more mature 125-day gestation sheep, antenatal steroids do not induce pulmonary surfactants during the periviable period, indicating a different response.
Targeted ablation of the surfactant protein D (SP-D) gene caused progressive pulmonary emphysema associated with pulmonary infiltration by foamy alveolar macrophages (AMs), increased hydrogen ...peroxide production, and matrix metalloproteinase (MMP)-2, -9, and -12 expression. In the present study, the mechanisms by which SP-D influences macrophage MMP activity were assessed in AMs from SP-D(-/-) mice. Tissue lipid peroxides and reactive carbonyls were increased in lungs of SP-D(-/-) mice, indicating oxidative stress. Immunohistochemical staining of AMs from SP-D(-/-) mice demonstrated that NF-kappaB was highly expressed and translocated to the nucleus. Increased NF-kappaB binding was detected by EMSA in nuclear extracts of AMs isolated from SP-D(-/-) mice. Antioxidants N-acetylcysteine and pyrrolidine dithiocarbamate inhibited MMP production by AMs from SP-D(-/-) mice. To assess whether increased oxidant production influenced NF-kappaB activation and production of MMP-2 and -9, AMs from SP-D(-/-) mice were treated with the NADPH oxidase inhibitors diphenylene iodonium chloride and apocynin. Inhibition of NADPH oxidase suppressed NF-kappaB binding by nuclear extracts and decreased production of MMP-2 and 9 in AMs from SP-D(-/-) mice. SN-50, a synthetic NF-kappaB-inhibitory peptide, decreased MMP production by AMs from SP-D(-/-) mice. Oxidant production and reactive oxygen species were increased in lungs of SP-D(-/-) mice, in turn activating NF-kappaB and MMP expression. SP-D plays an unexpected inhibitory role in the regulation of NF-kappaB in AMs.
To compare the short-term efficacy of surfactant administration by laryngeal mask airway versus endotracheal tube.
Preterm infants (28–35 weeks of gestational age), weighing 1kg or more, with ...respiratory distress syndrome, requiring nasal continuous positive airway pressure, with increased respiratory effort and/or fraction of inspired oxygen (FiO2)≥0.40 to maintain oxygen saturation 91–95%, were randomized to receive surfactant by LMA following nCPAP or by ETT following mechanical ventilation (MV). The primary outcome was a clinical response defined as FiO2≤0.30 three hours after surfactant. Secondary outcomes for LMA group were: need of surfactant retreatment during the first 24h, MV requirement, and presence of surfactant in gastric content.
Forty-eight patients were randomized; 26 in the LMA group and 22 in the ETT group. Six of 26 patients (23%) in the LMA group and five of 22 patients (22.7%) in the ETT group did not meet the primary outcome (p=0.977). Fourteen (53.8%) of the LMA patients were not intubated nor ventilated; 12 (46.1%) were ventilated: for surfactant failure (23%), for nCPAP failure (11.5%), and for late complications (11.5%). Groups were similar regarding prenatal status, birth conditions, and adverse events. No significant gastric content was found in 61.5% of the LMA patients. Oxygen and second dose surfactant requirements, arterial/alveolar ratio, and morbidities were similar among groups.
Surfactant administration by LMA showed short-term efficacy, with similar supplementary oxygen need compared to surfactant by ETT, and lower MV requirement. Further studies with larger sample size are necessary to confirm these results.
Comparar a eficácia de curto prazo da administração de surfactante por máscara laríngea em comparação ao tubo endotraqueal.
Neonatos prematuros (28–35 semanas de idade gestacional), pesando 1kg ou mais, com Síndrome do Desconforto Respiratório, necessitando pressão positiva nasal contínua nas vias aéreas, com aumento do esforço respiratório e/ou fração de oxigênio inspirado (FiO2)≥0,40 para manter a saturação de oxigênio 91–95%, foram randomizados para receber surfactante por ML seguido por nCPAP ou por TE seguido por ventilação mecânica (VM). O resultado clinico primário foi definido como FiO2 ≤ 0,30 três horas após o surfactante. Os resultados secundários do grupo de ML foram: necessidade de segunda dose de surfactante nas primeiras 24 horas, necessidade de VM e presença de surfactante no conteúdo gástrico.
Quarenta e oito pacientes foram randomizados; 26 no grupo de ML e 22 no grupo de TE. Seis dentre os 26 pacientes (23%) do grupo de ML e cinco dentre 22 pacientes (22,7%) do grupo de TE não apresentaram o resultado primário (p=0,977). Quatorze (53,8%) dos pacientes do grupo de ML não foram intubados nem ventilados; 12 (46,1%) foram submetidos a VM: por falha do surfactante (23%), por falha da nCPAP (11,5%) e por complicações tardias (11,5%). Os grupos foram semelhantes em relação às condições pré-natais e de nascimento e a ocorrência de eventos adversos. Não foi encontrado conteúdo gástrico significativo em 61,5% dos pacientes do grupo de ML. As necessidades de oxigênio e da segunda dose de surfactante, o índice arterial/alveolar e as morbidades foram semelhantes entre os grupos.
A administração de surfactante por ML mostrou eficácia de curto prazo com necessidade complementar de oxigênio semelhante ao surfactante por TE e menor necessidade de VM. Serão necessários estudos adicionais com tamanho da amostra maior para confirmar esses resultados.
Abstract Growing interest raised on circulating biomarkers of structural alveolar–capillary unit damage and very recent data support surfactant protein type B (SP-B) as the most promising candidate ...in this setting. With respect to other proteins proposed as possible markers of lung damage, SP-B has the some unique qualities: it is critical for the assembly of pulmonary surfactant, making its lack incompatible with life; it has no other known site of synthesis except alveolar epithelial cells differently from other surfactant proteins; and, it undergoes a proteolytic processing in a pulmonary-cell-specific manner. In the recent years circulating SP-B isoforms, mature or immature, have been demonstrated to be detectable in the circulation depending on the magnitude of the damage of alveolar capillary membrane. In the present review, we summarize the recent knowledge on SP-B regulation, function and we discuss its potential role as reliable biological marker of alveolar capillary membrane (dys)function in the context of heart failure.
Acquired immune responses elicited to recent strains of seasonal H1N1 influenza viruses provide limited protection against emerging A(H1N1) pandemic viruses. Accordingly, pre-existing or rapidly ...induced innate immune defenses are of critical importance in limiting early infection. Respiratory secretions contain proteins of the innate immune system, including members of the collectin and pentraxin superfamilies. These mediate potent antiviral activity and act as an initial barrier to influenza infection. In this study, we have examined the sensitivity of H1N1 viruses, including pandemic virus strains, for their sensitivity to collectins (surfactant protein SP-D and mannose-binding lectin MBL) and to the pentraxin PTX3. Human SP-D and MBL inhibited virus-induced hemagglutinating activity, blocked the enzymatic activity of the viral neuraminidase, and neutralized the ability of H1N1 viruses to infect human respiratory epithelial cells in a manner that correlated with the degree of glycosylation in the globular head of the hemagglutinin. Recent seasonal H1N1 viruses expressed three to four N-glycosylation sequons on the head of hemagglutinin and were very sensitive to inhibition by SP-D or MBL, whereas A(H1N1) pandemic viruses expressed a single N-glycosylation sequon and were resistant to either collectin. Of interest, both seasonal and pandemic H1N1 viruses were resistant to PTX3. Thus, unlike recent seasonal H1N1 strains of influenza virus, A(H1N1) pandemic viruses are resistant to the antiviral activities of innate immune proteins of the collectin superfamily.
Composition, surface activity and effects on pressure–volume (
P–
V) mechanics are examined for lavaged calf lung surfactant (LS) and the clinical exogenous surfactants Infasurf and Survanta. Lavaged ...LS and Infasurf had closely-matching compositions of phospholipids and neutral lipids. Survanta had higher levels of free fatty acids and triglycerides consistent with its content of added synthetic palmitic acid and tripalmitin. Infasurf and Survanta both contained less total protein than LS because of extraction with hydrophobic solvents, but the total protein content relative to phospholipid in Survanta was about 45% lower than in Infasurf. This difference was primarily due to surfactant protein (SP)-B, which was present by ELISA at a mean weight percent relative to phospholipid of 1.04% in LS, 0.90% in Infasurf, and 0.044% in Survanta. Studies on component fractions separated by gel permeation chromatography showed that SP-B was a major contributor to the adsorption, dynamic surface activity, and
P–
V mechanical effects of Infasurf, which approached whole LS in magnitude. Survanta had lower adsorption, higher minimum surface tension, and a smaller effect on surfactant-deficient
P–
V mechanics consistent with minimal contributions from SP-B. Addition of 0.05% by weight of purified bovine SP-B to Survanta did not improve surface or physiological activity, but added 0.7% SP-B improved adsorption, dynamic surface tension lowering, and
P–
V activity to levels similar to Infasurf. The SP-B content of lung surfactants appears to be a crucial factor in their surface activity and efficacy in improving surfactant-deficient pulmonary
P–
V mechanics.
Interstitial lung disease (ILD), a leading cause of morbidity and mortality in rheumatoid arthritis (RA), is highly prevalent, yet RA-ILD is underrecognized.
To identify clinical risk factors, ...autoantibodies, and biomarkers associated with the presence of RA-ILD.
Subjects enrolled in Brigham and Women's Hospital Rheumatoid Arthritis Sequential Study (BRASS) and American College of Rheumatology (ACR) cohorts were evaluated for ILD. Regression models were used to assess the association between variables of interest and RA-ILD. Receiver operating characteristic curves were generated in BRASS to determine if a combination of clinical risk factors and autoantibodies can identify RA-ILD and if the addition of investigational biomarkers is informative. This combinatorial signature was subsequently tested in ACR.
A total of 113 BRASS subjects with clinically indicated chest computed tomography scans (41% with a spectrum of clinically evident and subclinical RA-ILD) and 76 ACR subjects with research or clinical scans (51% with a spectrum of RA-ILD) were selected. A combination of age, sex, smoking, rheumatoid factor, and anticyclic citrullinated peptide antibodies was strongly associated with RA-ILD (areas under the curve, 0.88 for BRASS and 0.89 for ACR). Importantly, a combinatorial signature including matrix metalloproteinase 7, pulmonary and activation-regulated chemokine, and surfactant protein D significantly increased the areas under the curve to 0.97 (P = 0.002, BRASS) and 1.00 (P = 0.016, ACR). Similar trends were seen for both clinically evident and subclinical RA-ILD.
Clinical risk factors and autoantibodies are strongly associated with the presence of clinically evident and subclinical RA-ILD on computed tomography scan in two independent RA cohorts. A biomarker signature composed of matrix metalloproteinase 7, pulmonary and activation-regulated chemokine, and surfactant protein D significantly strengthens this association. These findings may facilitate identification of RA-ILD at an earlier stage, potentially leading to decreased morbidity and mortality.
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