Cardiovascular disease in Alpha 1 antitrypsin deficiency: an observational study assessing the role of neutrophil proteinase activity and the suitability of validated screening tools.

BACKGROUND: Alpha 1 Antitrypsin Deficiency (AATD) is a rare, inherited lung disease which shares features with Chronic Obstructive Pulmonary Disease (COPD) but has a greater burden of proteinase related tissue damage. These proteinases are associated with cardiovascular disease (CVD) in the general population. It is unclear whether patients with AATD have a greater risk of CVD compared to usual COPD, how best to screen for this, and whether neutrophil proteinases are implicated in AATD-associated CVD. This study had three aims. To compare CVD risk in never-augmented AATD patients to non-AATD COPD and healthy controls (HC). To assess relationships between CVD risk and lung physiology. To determine if neutrophil proteinase activity was associated with CVD risk in AATD. Cardiovascular risk was assessed by QRISK2® score and aortic stiffness measurements using carotid-femoral (aortic) pulse wave velocity (aPWV). Medical history, computed tomography scans and post-bronchodilator lung function parameters were reviewed. Systemic proteinase 3 activity was measured. Patients were followed for 4 years, to assess CVD development. RESULTS: 228 patients with AATD, 50 with non-AATD COPD and 51 healthy controls were recruited. In all COPD and HC participants, QRISK2® and aPWV gave concordant results (with both measures either high or in the normal range). This was not the case in AATD. Once aPWV was adjusted for age and smoking history, aPWV was highest and QRISK2® lowest in AATD patients compared to the COPD or HC participants. Higher aPWV was associated with impairments in lung physiology, the presence of emphysema on CT scan and proteinase 3 activity following adjustment for age, smoking status and traditional CVD risk factors (using QRISK2® scores) in AATD. There were no such relationships with QRISK2® in AATD. AATD patients with confirmed CVD at four-year follow up had a higher aPWV but not QRISK2® at baseline assessment. CONCLUSION: aPWV measured CVD risk is elevated in AATD. This risk is not captured by QRISK2®. There is a relationship between aPWV, lung disease and proteinase-3 activity. Proteinase-driven breakdown of elastin fibres in large arteries and lungs is a putative mechanism and forms a potential therapeutic target for CVD in AATD.

Quantitative analysis of protease recognition by inhibitors in plasma using microscale thermophoresis.

High abundance proteins like protease inhibitors of plasma display a multitude of interactions in natural environments. Quantitative analysis of such interactions in vivo is essential to study diseases, but have not been forthcoming, as most methods cannot be directly applied in a complex biological environment. Here, we report a quantitative microscale thermophoresis assay capable of deciphering functional deviations from in vitro inhibition data by combining concentration and affinity measurements. We obtained stable measurement signals for the substrate-like interaction of the disease relevant inhibitor α-1-antitrypsin (AAT) Z-variant with catalytically inactive elastase. The signal differentiates between healthy and sick AAT-deficient individuals suggesting that affinity between AAT and elastase is strongly modulated by so-far overlooked additional binding partners from the plasma.

Lung density associates with survival in alpha 1 antitrypsin deficient patients.

INTRODUCTION: CT density correlates with quality of life (QOL) scores and impaired upper zone lung density associates with higher mortality in alpha one antitrypsin deficiency (A1ATD). We hypothesised that decline in CT densitometry would relate to survival or deterioration in QOL in A1ATD. METHODS: All augmentation naïve PiZZ patients in the UK A1ATD registry with ≥ two successive quantitative CT scans were selected. Patients were divided into groups based on CT density decline and the relationship to survival and change in QOL compared by univariate analyses and multivariate Cox regression. Analyses were performed for whole lung, upper zone and lower zone density separately. Exploratory analyses of FEV1 subgroups were conducted. RESULTS: 110 patients were identified; 77 had whole lung and lung zone density recorded on two CT scans, 33 patients had upper zone data only on four scans. Decline in lower zone density associated with survival, even after adjustment for baseline lung density (p = 0.048), however upper zone density and whole lung density decline did not. This difference appeared to be driven by those with FEV1 >30% predicted. CONCLUSION: Rate of change in lung densitometry could predict survival in A1ATD.

PiSZ alpha-1 antitrypsin deficiency (AATD): pulmonary phenotype and prognosis relative to PiZZ AATD and PiMM COPD.

INTRODUCTION: The PiSZ genotype results in less severe deficiency of alpha-1 antitrypsin (AAT) than PiZZ. Less is known about phenotypic and prognostic features. METHODS: We studied 699 PiZZ, 126 PiSZ and 316 PiMM patients. All AAT deficiency (AATD) patients were augmentation naive. PiSZ were compared with PiZZ patients for clinical phenotype at baseline including CT findings, smoke exposure, progression of lung disease and survival. Similarly, PiSZ patients diagnosed as a result of investigation for possible lung disease (lung index cases) were compared with PiMM. Multivariable analytical techniques and matching (PiSZ to PiZZ) were employed to account for demographic differences. RESULTS: Pack-years smoked and FEV1 exhibited a negative correlation in PiSZ and ZZ patients (both r=-0.43), with emphysema and COPD occurring more commonly in PiZZ patients at <20 pack-year exposure. In multivariable analyses, PiSZ patients were less likely to have emphysema (p<0.01) and had better survival than PiZZ (p=0.017), but lung function decline did not differ significantly. 42% of PiSZ patients had upper-zone-dominant emphysema on CT scan. Analyses of AAT level confirmed a critical threshold at 11 µM, particularly with regard to phenotypes classical of PiZZ AATD.Significant baseline differences suggested that PiSZ had presented earlier to health services than PiMM. Once this was accounted for, risk of emphysema did not differ between PiSZ and PiMM although survival was lower in PiMM patients (p<0.01). CONCLUSIONS: PiSZ patients are less susceptible to cigarette smoke than PiZZ. The pattern of emphysema may be similar at diagnosis to usual COPD.

Disease associations in alpha-1-antitrypsin deficiency.

INTRODUCTION: In addition to emphysema alpha-1-antitrypsin deficiency (AATD) has been shown to be associated with several inflammatory conditions, including bronchiectasis, vasculitis, (in particular Wegener's granulomatosis), and panniculitis, suggesting neutrophil proteinases also play a role in their pathophysiology. However, it remains unknown whether other inflammatory diseases are also more prevalent in AATD than the general population. The current study describes the prevalence of other co-morbidities in AATD with particular emphasis on inflammatory bowel disease. METHODS AND RESULTS: The case notes of 651 PiZZ or PiZnull patients attending the UK national centre for AATD between 1996 and 2011 were reviewed. The prevalence of inflammatory bowel disease (1.5%) was higher than that predicted in the UK (0.4%). Ten patients had a confirmed diagnosis of ulcerative colitis, and 1 had Crohn's disease. In 2 cases there was a family history of inflammatory bowel disease and all but 1 patient were ex or never smokers. There was also a higher prevalence of hypothyroidism in this patient group than expected for the UK population - 26 cases (7.2% of females and 1.3% of males). CONCLUSIONS: The current study of the UK cohort of patients with AATD confirmed a higher prevalence of ulcerative colitis than would be expected in the general population, providing further evidence of a potential link between these 2 conditions. In addition, the data suggested a potential link between hypothyroidism and AATD.

Vitamin D-binding protein contributes to COPD by activation of alveolar macrophages.

BACKGROUND: Vitamin D-binding protein (DBP) genetic polymorphisms have been associated with chronic obstructive pulmonary disease (COPD). DBP has an indirect role in macrophage activation; thus it was hypothesised that DBP is present in the airway and contributes to lung disease by this mechanism. METHODS: 471 PiZZ subjects with α1-antitrypsin deficiency (AATD) were genotyped for tag single nucleotide polymorphisms (SNPs) covering the DBP gene (GC), together with known functional variants, prior to seeking association with COPD phenotypes. 140 subjects with usual COPD and 480 controls were available for replication. Vitamin D and DBP levels were measured by tandem mass spectrometry and ELISA, respectively, in serum and DBP in the sol phase of sputum in a subset of 60 patients. Concentrations were related to phenotype and to alveolar macrophage activation. RESULTS: rs2070741 was associated with airway bacterial colonisation (p=0.04) and bronchiectasis (p=0.01), as was rs7041 (p=0.03) which also influenced vitamin D concentrations (p=0.01). The GC2 variant predisposed to bronchiectasis in AATD (p=0.04) and protected against COPD (p=0.05); the latter association was replicated in usual COPD versus controls (p=0.04). Circulating DBP related inversely to forced expiratory volume in 1 s (FEV(1)) (p=0.02), in direct contrast to vitamin D, where deficiency related to low FEV(1) (p=0.04). Sol DBP related directly to alveolar macrophage activation (p=0.004). CONCLUSIONS: The genetic association of DBP with COPD may be mediated by effects on macrophage activation, since DBP relates to FEV(1), and affects macrophage activation. Vitamin D effects may be independent of this, relating more strongly to innate immunity.

Smoke exposure as a determinant of autoantibody titre in α1-antitrypsin deficiency and COPD.

Liberation of elastin peptides from damaged lung may be a mechanism of autoimmune lung disease. Citrullination, and anti-citrullinated protein antibody formation occurs in smokers, but the role of smoking in autoantibody generation relevant to pulmonary disease is unclear. Anti-elastin, anti-cyclic citrullinated peptide (anti-CCP) and anti-mutated citrullinated vimentin (anti-MCV) antibodies were measured in 257 subjects with α1-antitrypsin deficiency (AATD), 113 subjects with usual chronic obstructive pulmonary disease (COPD) and 22 healthy nonsmokers. Levels were compared between groups, against phenotypic features and against smoke exposure. Anti-elastin antibodies were higher in controls relative to AATD (p = 0.008) and usual COPD (p < 0.00001), and in AATD relative to usual COPD (p < 0.00001). Anti-elastin levels showed a threshold at 10 pack-yrs, being higher in those who had smoked less (p = 0.004). No relationships between antibody levels and clinical phenotype were seen after adjustment for smoke exposure. Anti-CCP antibodies were higher in usual COPD than AATD (p = 0.002) but the relationship to smoke exposure was less clear. Smoke exposure is the main determinant of anti-elastin antibody levels, which fall after 10 pack-yrs. Local antibody complexes may be a better measure of elastin directed autoimmunity than circulating levels.

The vitamin D axis in the lung: a key role for vitamin D-binding protein.

There has been much recent interest in the role of the vitamin D axis in lung disease, which includes vitamin D, vitamin D receptor (VDR) and vitamin D-binding protein (VDBP; also known as Gc-globulin). VDBP is a serum protein which has immunomodulatory functions relevant in the lung, predominantly relating to macrophage activation and neutrophil chemotaxis. Variations within its gene are also associated with airways disease, implying a role for the protein product in pathogenesis. Thus far the majority of evidence relates to chronic obstructive pulmonary disease (COPD), but is scant in other airways diseases, such as asthma and bronchiectasis. VDBP also acts as a scavenger protein to clear extracellular G-actin released from necrotic cells, which may be of relevance in severe lung infections and acute lung injury. Vitamin D protects against the development of cancer and tuberculosis, although optimal levels are unknown. The majority of circulating vitamin D is bound to VDBP, and its uptake into cells occurs in both bound and unbound forms, which suggests the role of VDBP warrants further study in these conditions as well. This article reviews the evidence of the role VDBP and its gene (GC) in a range of lung diseases, including asthma, COPD and tuberculosis.

Pulmonary infection in Wegener granulomatosis and idiopathic pulmonary fibrosis.

RATIONALE: Wegener granulomatosis (WG) has previously been associated with increased nasal carriage of Staphylococcus aureus, but no studies have investigated the occurrence of pathogen growth in the lower airways. OBJECTIVES: To culture bronchoalveolar lavage fluid (BALF) from patients with WG, patients with idiopathic pulmonary fibrosis (IPF) and normal controls. METHODS: 33 patients with WG, 22 with IPF and 8 normal controls underwent bronchoscopy and bronchoalveolar lavage. Quantitative culture established bacterial levels in the lower airways. Culture experiments were designed to investigate whether BALF is a supportive environment for S aureus growth. BALF cytokines were measured by ELISA. RESULTS: Pathogens were commonly grown from BALF of patients with WG and those with IPF. S aureus was particularly associated with patients with WG both in relapse and in remission. BALF levels of interleukin 1 receptor antagonist (IL1ra) were statistically significantly elevated in those patients who grew a pathogen from lavage fluid. BALF from patients with WG and IPF stimulated S aureus growth compared with normal lavage fluid. CONCLUSIONS: Pathogens are more commonly isolated from BALF from patients with WG than from that of patients with IPF or normal controls, and with a different culture profile. IL1ra was associated with pathogen growth in WG and IPF. WG BALF is a trophic environment for S aureus growth. Pulmonologists treating patients with acute or relapsing WG should consider bronchoscopic microbiological sampling and consider antibiotics with antistaphylococcal activity.

Outdoor air pollution is associated with disease severity in alpha1-antitrypsin deficiency.

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, SO(2) and NO(2) 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 alpha(1)-antitrypsin deficiency, identifying a group susceptible to ambient air pollution.

Exploring the role of CT densitometry: a randomised study of augmentation therapy in alpha1-antitrypsin deficiency.

Assessment of emphysema-modifying therapy is difficult, but newer outcome measures offer advantages over traditional methods. The EXAcerbations and Computed Tomography scan as Lung End-points (EXACTLE) trial explored the use of computed tomography (CT) densitometry and exacerbations for the assessment of the therapeutic effect of augmentation therapy in subjects with alpha(1)-antitrypsin (alpha(1)-AT) deficiency. In total, 77 subjects (protease inhibitor type Z) were randomised to weekly infusions of 60 mg x kg(-1) human alpha(1)-AT (Prolastin) or placebo for 2-2.5 yrs. The primary end-point was change in CT lung density, and an exploratory approach was adopted to identify optimal methodology, including two methods of adjustment for lung volume variability and two statistical approaches. Other end-points were exacerbations, health status and physiological indices. CT was more sensitive than other measures of emphysema progression, and the changes in CT and forced expiratory volume in 1 s were correlated. All methods of densitometric analysis concordantly showed a trend suggestive of treatment benefit (p-values for Prolastin versus placebo ranged 0.049-0.084). Exacerbation frequency was unaltered by treatment, but a reduction in exacerbation severity was observed. In patients with alpha(1)-AT deficiency, CT is a more sensitive outcome measure of emphysema-modifying therapy than physiology and health status, and demonstrates a trend of treatment benefit from alpha(1)-AT augmentation.

Rate of progression of lung function impairment in alpha1-antitrypsin deficiency.

The aim of the present study was to identify alpha(1)-antitrypsin (alpha(1)-AT)-deficient patients who had rapidly progressive disease. PiZ patients (n = 101) underwent annual lung function measurements over a 3-yr period, and the results were related to factors that may influence decline. The mean annual decline in forced expiratory volume in 1 s (FEV(1)) was 49.9 mL. The greatest FEV(1) decline occurred in the moderate severity group (FEV(1) 50-80% of the predicted value), with a mean annual decline of 90.1 mL, compared with 8.1 mL in the very severe group (FEV(1) <30% pred). However, annual decline in transfer coefficient of the lung for carbon monoxide (K(CO)) was greatest in the severe and very severe groups. When the whole group was divided into tertiles of FEV(1) decline, the fast tertile compared with the slow tertile had more patients with bronchodilator reversibility (BDR) (73 versus 41%; p = 0.010), more males (79 versus 56%; p = 0.048) and lower body mass index (BMI) (24.0 versus 26.1; p = 0.042). Logistic regression analyses confirmed that FEV(1) decline was independently associated with BMI, BDR, exacerbation rate and high physical component 36-item short-form health survey scores. In PiZ alpha(1)-AT-deficient patients, FEV(1) decline was greatest in moderate disease, unlike K(CO) decline, which was greatest in severe disease. The FEV(1) decline showed associations with BDR, BMI, sex and exacerbation rate.

Adrenal suppression in bronchiectasis and the impact of inhaled corticosteroids.

The present study identified three patients with bronchiectasis receiving inhaled corticosteroids (ICSs) who had symptomatic adrenal suppression secondary to ICS. The prevalence of adrenal suppression is unknown in bronchiectasis. The frequency of adrenal suppression and the impact of ICS use in bronchiectasis patients were examined. In total, 50 outpatients (33 receiving ICSs) underwent a short Synacthen test and completed a St George's Respiratory Questionnaire (SGRQ). Symptoms of adrenal suppression, steroid use and lung function were compared between subjects who were suppressed and those who were not. Adrenal suppression was evident in 23.5% of subjects who did not receive ICSs and 48.5% of those who did. Basal cortisol and the increments by which cortisol increased 30 min after Synacthen were lower in suppressed than in nonsuppressed subjects. The incremental cortisol rise was negatively correlated with SGRQ impacts and total score, suggesting a worse quality of life in those who had an impaired adrenal response. The greatest frequency of generalised symptoms was seen in the suppressed group. A significant proportion of subjects with bronchiectasis have evidence of adrenal suppression, and this is increased when inhaled corticosteroids are also used. Impairment of the cortisol response to stimulation is associated with poorer health status.

Validation of assays for inflammatory mediators in exhaled breath condensate.

The use of exhaled breath condensate (EBC) as a tool for noninvasive assessment of lung inflammation is becoming commonplace. Many authors use commercial ELISA kits to measure inflammatory mediators within EBC. However, the very low concentrations of mediators within EBC are often below the commercially validated concentration range of the relevant ELISA and crucially below the linear part of the sigmoid standard curve. The present study seeks to validate a series of assays for use in EBC and to compare the results in EBC with those from matched sol phase sputum samples. The following mediators were measured by ELISA: leukotriene (LT)B(4), interleukin (IL)-8, secretory leukoprotease inhibitor and alpha(1)-antitrypsin (AAT). Myeloperoxidase was measured by chromogenic substrate assay. Mediator concentrations reached the lower limit of quantification in only one assay (AAT) in 19.6% of subjects, while mediator concentrations reached the lower limit of detection in three assays (LTB(4), IL-8 and AAT in 31, 6.5 and 61% of subjects, respectively). No significant correlations were present between any mediators in EBC and sol phase sputum. The results of the present study indicate that care must be exercised when interpreting mediator measurements in exhaled breath condensate and that assays must be validated at concentrations relevant to those found within the biological fluid.