European Respiratory Journal 2009; 34:346-353
The aim of this study was to determine whether long-term air pollution exposure is associated with clinical phenotype in alpha 1-antitrypsin deficiency.
In total, 304 PiZZ subjects underwent full lung function testing and quantitative high-resolution computed tomography to identify the presence and severity of the disease. Mean annual air pollutant data for 2006 was matched to the location of patients' houses and used in regression models to identify phenotypic associations with pollution, controlling for covariates. Relative trends in pollution levels were assessed to validate use of a single year's data to indicate long-term exposure.
Pollutant levels correlated significantly with one another, with higher levels of primary particles, SO2 and NO2 being associated with lower ozone levels. Regression models showed that estimated higher exposure to ozone was associated with worse gas transfer and more severe emphysema. Regression parameters suggested that significance from other pollutants was due to collinearity with ozone. The 2006 pollutant levels showed linear relationships with cumulative years, thus validating the model.
Higher exposures to ozone may be associated with worse respiratory status in 1-antitrypsin deficiency, identifying a group susceptible to ambient air pollution.
Division of Medical Sciences, School of Geography, Earth and Environmental Sciences, Dept of Occupational and Environmental Medicine, University of Birmingham, and 4Lung Investigation Unit, University Hospitals Birmingham, Birmingham, UK.
Tuesday
Thursday
Lung volume reduction surgery for patients with alpha-1 antitrypsin deficiency emphysema
Currently, A1AD is recognized in approximately 2% of patients who have emphysema, although this may be an underestimation of the prevalence of this disease. Given the relatively young age at which patients who have A1AD present with emphysema, therapies aimed at slowing the progression of this disease are imperative. In addition to abstaining from smoking, the use of augmentation therapy may benefit some patients who have moderate airflow obstruction. For patients who have severe airflow obstruction, the most effective therapy is surgical.
Despite a possible increased risk for infectious complications, transplantation remains a viable option for these patients who have long-term results mirroring those of patients transplanted for smoking-related COPD. Given limited donor availability, however, LVRS must be considered in these patients possibly as definitive therapy but more likely as a bridge to transplantation. LVRS for patients who have A1AD remains relatively uncommon despite a general perception that it remains a surgical option.
In a survey of European thoracic surgical centers, Hamacher and colleagues42 found that two thirds of respondents included A1AD in their list of indications for LVRS. Although the durability of the benefits derived from LVRS in patients who have A1AD seems inferior to that of patients who have COPD, the available data show improved 6-minute walk distances and decreased dyspnea persisting for 1 to 2 years after LVRS in patients who had A1AD. Further experience is necessary to determine whether or not subgroups of patients who have A1AD, such as those who have clear heterogeneous distribution, may derive more long-lasting improvement from LVRS.
Donahue JM, Cassivi SD.
Division of General Thoracic Surgery, University of Maryland, 22 South Greene Street, N4E35, Baltimore, MD 21201, USA
Despite a possible increased risk for infectious complications, transplantation remains a viable option for these patients who have long-term results mirroring those of patients transplanted for smoking-related COPD. Given limited donor availability, however, LVRS must be considered in these patients possibly as definitive therapy but more likely as a bridge to transplantation. LVRS for patients who have A1AD remains relatively uncommon despite a general perception that it remains a surgical option.
In a survey of European thoracic surgical centers, Hamacher and colleagues42 found that two thirds of respondents included A1AD in their list of indications for LVRS. Although the durability of the benefits derived from LVRS in patients who have A1AD seems inferior to that of patients who have COPD, the available data show improved 6-minute walk distances and decreased dyspnea persisting for 1 to 2 years after LVRS in patients who had A1AD. Further experience is necessary to determine whether or not subgroups of patients who have A1AD, such as those who have clear heterogeneous distribution, may derive more long-lasting improvement from LVRS.
Donahue JM, Cassivi SD.
Division of General Thoracic Surgery, University of Maryland, 22 South Greene Street, N4E35, Baltimore, MD 21201, USA
Wednesday
Mortality in alpha-1-antitrypsin deficiency in the United Kingdom.
University Hospital Birmingham/ University of Birmingham, UK.
BACKGROUND: Four hundred and eighty-eight PiZ alpha-1-antitrypsin deficient patients, who had joined the UK registry over a 9-year period, were followed in an observational study to determine mortality. None had received A1AT augmentation therapy.
METHODS: Cause of death was confirmed from death certification and medical records. Patients were censored according to length of time on the program or until they withdrew from the program. RESULTS: There were 56 deaths of which 30 were attributed to respiratory causes. Of the remaining 26 deaths, 4 were due to complications from lung transplant, 6 due to liver disease (including 2 post-liver transplant) and the other 16 due to a variety of causes. Kaplan-Meier plots indicated a cumulative hazard for mortality of 18.1% in 9 years, correcting for time of follow up. When categorised for FEV(1) percent-predicted, the group with severe impairment had increased mortality (p=<0.001) compared with the mild group and there was a direct relationship between severity and mortality. The severe group had increased mortality compared with the mild group when categorised for KCO percent-predicted (p<0.001), RV/TLC ratio (p<0.001) or emphysema score on CT scan (p<0.001 upper zone). Cox regression analyses indicated that these relationships remained when corrected for age. There were no differences in mortality after categorisation for educational level or occupational group.
CONCLUSION: Mortality in a cohort of A1AT deficient patients (PiZ phenotype) in the UK was 2% per year and was associated with lung function impairment and emphysema severity on CT scan, but not social status
BACKGROUND: Four hundred and eighty-eight PiZ alpha-1-antitrypsin deficient patients, who had joined the UK registry over a 9-year period, were followed in an observational study to determine mortality. None had received A1AT augmentation therapy.
METHODS: Cause of death was confirmed from death certification and medical records. Patients were censored according to length of time on the program or until they withdrew from the program. RESULTS: There were 56 deaths of which 30 were attributed to respiratory causes. Of the remaining 26 deaths, 4 were due to complications from lung transplant, 6 due to liver disease (including 2 post-liver transplant) and the other 16 due to a variety of causes. Kaplan-Meier plots indicated a cumulative hazard for mortality of 18.1% in 9 years, correcting for time of follow up. When categorised for FEV(1) percent-predicted, the group with severe impairment had increased mortality (p=<0.001) compared with the mild group and there was a direct relationship between severity and mortality. The severe group had increased mortality compared with the mild group when categorised for KCO percent-predicted (p<0.001), RV/TLC ratio (p<0.001) or emphysema score on CT scan (p<0.001 upper zone). Cox regression analyses indicated that these relationships remained when corrected for age. There were no differences in mortality after categorisation for educational level or occupational group.
CONCLUSION: Mortality in a cohort of A1AT deficient patients (PiZ phenotype) in the UK was 2% per year and was associated with lung function impairment and emphysema severity on CT scan, but not social status
Monday
Monoclonal anti-neutrophil elastase antibody characterisation: Ability to block function, detect free versus serpin-complexed enzyme and stain intrace
Four commercially available monoclonal antibodies (clones NP57, 256-3K1, 39A and 203) were characterised for their ability to block human neutrophil elastase (HNE) activity; capture free purified HNE or neutralised HNE in complex with alpha-1-antitrypsin (AAT); detect HNE and HNE–AAT by Western blot analysis; and detect intracellular HNE by flow cytometry. The ability to block small substrate cleavage by HNE ranged from 0% (265-3K1) to 15–18% (39A and 203) to 100% (NP57). All antibodies had the ability to capture free HNE with varying degrees of sensitivity, but HNE neutralisation by AAT resulted in complete loss of detection (NP57) to 2–4-fold decreased detection (39A and 203) to a 8-fold increase in detection (265-3K1). None of the monoclonal antibodies could detect 200 ng of free HNE, or HNE in complex with AAT, by Western blot analysis, which was easily detected by polyclonal antibodies. NP57 and 265-3K1 gave 10-fold higher fluorescence when detecting intracellular HNE than 39A and 203, and intracellular fluorescence decreased by 10–28% following maximal stimulation of purified neutrophils with fMLP and cytochalasin B (compared to 40% release determined by functional assay). However, for sub-maximal stimulation of neutrophils intracellular anti-HNE antibody binding increased, likely due to increased accessibility following redistribution of enzyme, indicating that measuring residual intracellular HNE as an index of release is a less reliable method than directly measuring extracellular HNE.
ARTICLE
ARTICLE
Wednesday
Terminally misfolded or unassembled proteins in the early secretory pathway are degraded by a ubiquitin- and proteasome-dependent process known as ER-
Terminally misfolded or unassembled proteins in the early secretory pathway are degraded by a ubiquitin- and proteasome-dependent process known as ER-associated degradation (ERAD). How substrates of this pathway are recognized within the ER and delivered to the cytoplasmic ubiquitin-conjugating machinery is unknown. We report here that OS-9 and XTP3-B/Erlectin are ER-resident glycoproteins that bind to ERAD substrates and, through the SEL1L adaptor, to the ER-membrane-embedded ubiquitin ligase Hrd1. Both proteins contain conserved mannose 6-phosphate receptor homology (MRH) domains, which are required for interaction with SEL1L, but not with substrate. OS-9 associates with the ER chaperone GRP94 which, together with Hrd1 and SEL1L, is required for the degradation of an ERAD substrate, mutant 1-antitrypsin. These data suggest that XTP3-B and OS-9 are components of distinct, partially redundant, quality control surveillance pathways that coordinate protein folding with membrane dislocation and ubiquitin conjugation in mammalian cells.
Monday
Alpha-1 antitrypsin Null mutations and severity of emphysema
Background
Alpha-1 antitrypsin (AAT) deficiency is an autosomal-codominant disorder, caused by mutations in the SERPINA1 gene on chromosome 14. Individuals affected by the most common mutations, SZ and ZZ, have serum AAT concentrations of 25% and 15% of normal levels, and present a higher risk of emphysema. Mutations causing total absence of serum AAT (Null mutations) were suggested to be associated with very early onset emphysema but their clinical phenotype is poorly known.
Hypothesis
Absence of AAT in Null mutations results in more severe emphysema as compared to ZZ and SZ.
Methods
We genotyped all known Dutch subjects (n=12) with absent serum AAT, and compared their lung function values (FEV1 and KCO) with those of individuals with ZZ and SZ genotype, matched for age and smoking history.
Results
All subjects with absent serum AAT presented homozygous Null mutations. In three subjects, a new mutation in exon 2 of the SERPINA1 gene was found. Subjects with Null mutations showed significantly lower lung function values than SZ and ZZ individuals (p=0.000 and 0.001 for FEV1 and KCO, respectively). In all groups, there was a positive correlation between serum AAT and lung function values (p=0.025 and 0.014 for FEV1 and KCO, respectively).
Conclusions
Serum levels of AAT are correlated with the severity of pulmonary phenotype. Subjects with Null mutations should be considered a subgroup at particularly high risk of emphysema within AAT deficiency (AATD). Early detection of carriers of this genotype would be important for preventive and therapeutic interventions.
Laura Fregonesea, Jan Stolka, Rune R. Frantsb and Barbera Veldhuisen
ARTICLE
Alpha-1 antitrypsin (AAT) deficiency is an autosomal-codominant disorder, caused by mutations in the SERPINA1 gene on chromosome 14. Individuals affected by the most common mutations, SZ and ZZ, have serum AAT concentrations of 25% and 15% of normal levels, and present a higher risk of emphysema. Mutations causing total absence of serum AAT (Null mutations) were suggested to be associated with very early onset emphysema but their clinical phenotype is poorly known.
Hypothesis
Absence of AAT in Null mutations results in more severe emphysema as compared to ZZ and SZ.
Methods
We genotyped all known Dutch subjects (n=12) with absent serum AAT, and compared their lung function values (FEV1 and KCO) with those of individuals with ZZ and SZ genotype, matched for age and smoking history.
Results
All subjects with absent serum AAT presented homozygous Null mutations. In three subjects, a new mutation in exon 2 of the SERPINA1 gene was found. Subjects with Null mutations showed significantly lower lung function values than SZ and ZZ individuals (p=0.000 and 0.001 for FEV1 and KCO, respectively). In all groups, there was a positive correlation between serum AAT and lung function values (p=0.025 and 0.014 for FEV1 and KCO, respectively).
Conclusions
Serum levels of AAT are correlated with the severity of pulmonary phenotype. Subjects with Null mutations should be considered a subgroup at particularly high risk of emphysema within AAT deficiency (AATD). Early detection of carriers of this genotype would be important for preventive and therapeutic interventions.
Laura Fregonesea, Jan Stolka, Rune R. Frantsb and Barbera Veldhuisen
ARTICLE
Friday
Alpha-1 antitrypsin (A1AT) is a serine anti-protease produced chiefly by the liver. A1AT deficiency is a genetic disorder characterized by serum level
Summary
alpha-1 antitrypsin (A1AT) is a serine anti-protease produced chiefly by the liver. A1AT deficiency is a genetic disorder characterized by serum levels of less than 11 μmol/L and is associated with liver and lung manifestations. The liver disease, which occurs in up to 15% of A1AT-deficient individuals, is a result of toxic gain-of-function mutations in the A1AT gene, which cause the A1AT protein to fold aberrantly and accumulate in the endoplasmic reticulum of hepatocytes. The lung disease is associated with loss-of-function, specifically decreased anti-protease protection on the airway epithelial surface. The so-called ‘Z’ mutation in A1AT deficiency encodes a glutamic acid-to-lysine substitution at position 342 in A1AT and is the most common A1AT allele associated with disease. Here we review the current understanding of the molecular pathogenesis of A1AT deficiency and the best clinical management protocols.
C. M. Greene1 , S. D. W. Miller1, T. Carroll1, C. McLean1, M. O’Mahony1, M. W. Lawless1, 2, S. J. O’Neill1, C. C. Taggart1, 3 and N. G. McElvaney1
alpha-1 antitrypsin (A1AT) is a serine anti-protease produced chiefly by the liver. A1AT deficiency is a genetic disorder characterized by serum levels of less than 11 μmol/L and is associated with liver and lung manifestations. The liver disease, which occurs in up to 15% of A1AT-deficient individuals, is a result of toxic gain-of-function mutations in the A1AT gene, which cause the A1AT protein to fold aberrantly and accumulate in the endoplasmic reticulum of hepatocytes. The lung disease is associated with loss-of-function, specifically decreased anti-protease protection on the airway epithelial surface. The so-called ‘Z’ mutation in A1AT deficiency encodes a glutamic acid-to-lysine substitution at position 342 in A1AT and is the most common A1AT allele associated with disease. Here we review the current understanding of the molecular pathogenesis of A1AT deficiency and the best clinical management protocols.
C. M. Greene1 , S. D. W. Miller1, T. Carroll1, C. McLean1, M. O’Mahony1, M. W. Lawless1, 2, S. J. O’Neill1, C. C. Taggart1, 3 and N. G. McElvaney1
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