Increased circulating levels of alpha1-antitrypsin and calprotectin are associated with reduced gas diffusion in the lungs

Serum Levels of Alpha1-antitrypsin and Their Relationship With COPD in the General Spanish Population

BACKGROUND

Low plasma level of alpha1-antitrypsin (AAT) is an established risk factor for early-onset chronic obstructive lung disease (COPD). However, less attention is given to the levels of AAT in the general population.

METHODS

This is a part of a multicentre, population-based study conducted at 11 sites throughout Spain. Plasma levels of AAT were available for 837 persons with a mean (SD) age of 58.05 (11.3) years: 328-smokers, 272-ex-smokers and 237 non-smokers. Out of 837, 303 (36.2%) had a diagnosis of COPD, 222 (26.5%) had respiratory symptoms but no COPD, and 312 (37.3%) were healthy controls.

RESULTS

In the whole cohort, the mean level of plasma AAT was 1.51 (0.47)g/L. Levels were higher in COPD patients [1.55 (0.45)g/L] and individuals with respiratory symptoms [1.57 (0.47)g/L] than in controls [1.43 (0.47)g/L], p<0.001, a finding which persisted after correction for age and CRP. Plasma AAT levels were negatively associated with FEV1/FVC ratio, after adjustment for age, sex, smoking status, CRP, TNFα, fibrinogen and albumin. The risk for COPD was significantly associated with higher AAT levels in univariate and multivariate models, with odds ratios of 1.8 and 1.5, respectively. In the univariate and multivariate models smoking status, gender, and CRP levels were also associated with COPD probability, demonstrating that they act independently.

CONCLUSION

Increased circulating levels of AAT, similarly to CRP and other markers of systemic inflammation, is an important feature of COPD. Our results highlight a complex interrelationship between levels of AAT and health of respiratory system.

Inflammatory markers in chronic obstructive pulmonary disease patients with different α1 antitrypsin genotypes

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) has been recently defined as a systemic pulmonary inflammatory disease, and congenital α1 antitrypsin deficiency is one of the well-established genetic risk factors for chronic obstructive pulmonary disease. The aim of our study was to evaluate the possible associations of α1 antitrypsin with inflammatory markers - CRP, sCD14, TNF-α, sTNFR-1, and sTNFR-2 - in patients with COPD with different α1 antitrypsin genotypes.

MATERIAL AND METHODS

Serum biomarkers from patients (n = 355) with COPD, defined according to the GOLD criteria, were analyzed using commercial ELISA kits; α1 antitrypsin concentrations were determined by nephelometry, and α1 antitrypsin phenotyping was carried out by means of isoelectric focusing.

RESULTS

No significant differences in CRP, TNF-α, sTNFR-1, sTNFR-2, and sCD14 levels were found comparing COPD patients with different genotypes. In patients without α1 antitrypsin deficiency (PI*MM), a significant negative correlation between lung function (FEV(1)) and serum α1 antitrypsin (r = -0.522, p = 0.03) and CRP concentration (r = -0.590, p = 0.011) was detected. The level of α1 antitrypsin positively correlated with: a) CRP concentration (r = 0.671, p = 0.005), b) sCD14 (r = 0.510, p = 0.008) and c) sTNFR-1 (r = 0.567, p = 0.007).

CONCLUSIONS

In patients without α1 antitrypsin deficiency, the positive association of α1 antitrypsin concentration with CRP, sCD14, and sTNFR-1 and the negative association with FEV(1) show the importance of α1 antitrypsin as a marker of systemic inflammation.

Quantitative CT measures of emphysema and airway wall thickness are related to D(L)CO

There is limited knowledge on the relationship between diffusing capacity of the lung for carbon monoxide (D(L)CO) and quantitative computed tomography (CT) measures of emphysema and airway wall thickness.

STUDY QUESTION

What is the relationship between D(L)CO and the quantitative CT measures of emphysema and airway wall thickness in subjects with and without COPD?

METHODS

We included 288 COPD subjects (70% men) and 425 non-COPD subjects (54% men). All subjects were current or ex-smokers older than 40 years and all subjects underwent spirometry, diffusing capacity tests and CT examination. Quantitative CT measures included % low attenuation areas < -950 HU (%LAA) and standardized airway wall thickness (AWT-Pi10).

RESULTS

Multiple linear regression analyses showed significant associations between D(L)CO and both %LAA and AWT-Pi10 in the COPD group. The adjusted regression coefficients (SE) for D(L)CO (mmol min(-1) kPa(-1)) were -1.15 (0.11) per 10% increase in %LAA and 0.08 (0.03) per 0.1 mm increase in AWT-Pi10, and the models' adjusted R(2) was 0.65 and 0.49, respectively.

CONCLUSIONS

CT measured emphysema explains a large fraction of the variation of D(L)CO among COPD subjects, and more so in men. Airway wall thickness is also significantly associated with D(L)CO, but explains a much smaller fraction of the variation.

Circulating alpha1-antitrypsin in the general population: determinants and association with lung function

BACKGROUND

Severe alpha1-antitrypsin (AAT) deficiency associated with low AAT blood concentrations is an established genetic COPD risk factor. Less is known about the respiratory health impact of variation in AAT serum concentrations in the general population. We cross-sectionally investigated correlates of circulating AAT concentrations and its association with FEV1.

METHODS

In 5187 adults (2669 females) with high-sensitive c-reactive protein (CRP) levels < or = 10 mg/l from the population-based Swiss SAPALDIA cohort, blood was collected at the time of follow-up examination for measuring serum AAT and CRP.

RESULTS

Female gender, hormone intake, systolic blood pressure, age in men and in postmenopausal women, as well as active and passive smoking were positively, whereas alcohol intake and BMI inversely correlated with serum AAT levels, independent of CRP adjustment. We observed an inverse association of AAT with FEV1 in the total study population (p < 0.001), that disappeared after adjustment for CRP (p = 0.28). In addition, the AAT and FEV1 association was modified by gender, menopausal status in women, and smoking.

CONCLUSION

The results of this population-based study reflect a complex interrelationship between tobacco exposure, gender related factors, circulating AAT, systemic inflammatory status and lung function.

Endotoxin receptor CD14 in PiZ alpha-1-antitrypsin deficiency individuals

BACKGROUND

CD14, a receptor for lipopolysaccharides (LPS), is found in both a membrane-bound form (mCD14) and a soluble form (sCD14). It is suggested that sCD14 is mainly released from blood monocytes by serine protease-mediated shedding. Because alpha1-antitrypsin (AAT), an inhibitor of serine proteases, has been shown to regulate CD14 expression in human monocytes in vitro, we sought to investigate plasma levels of sCD14 and monocyte expression of mCD14 in subjects at age 30 years with normal MM and deficient PiZZ and PiSZ genotypes of AAT.

METHODS

Plasma levels of AAT and sCD14 were measured in 75 PiZZ and 34 PiSZ individuals with normal lung function identified from the Swedish neonatal AAT deficiency screening, and in 95 age matched PiMM controls. The mCD14 expression in monocytes from 9 PiZZ, 6 PiSZ and 11 PiMM subjects was analysed by FACS and Quantitative Real Time Reverse Transcription PCA.

RESULTS

As expected, plasma AAT concentrations were PiMM>PiSZ>PiZZ (p < 0.001). Plasma sCD14 levels were higher in PiZZ than in PiMM subjects (p < 0.01). The expression level of mCD14 was higher (1.89-fold) in monocytes isolated from PiZZ subjects compared to PiMM controls (p = 0.00189).

CONCLUSION

This study is the first to show higher levels of plasma sCD14 and monocyte mCD14 expression in young, clinically healthy PiZZ AAT subjects.

C-reactive Protein As a Predictor of Prognosis in Chronic Obstructive Pulmonary Disease

RATIONALE

Patients with chronic obstructive pulmonary disease (COPD) have an ongoing systemic inflammation, which can be assessed by measuring serum C-reactive protein (CRP).

OBJECTIVE

To determine whether increased serum CRP in individuals with airway obstruction predicts future hospitalization and death from COPD.

METHODS

We performed a cohort study with a median of 8-yr follow-up of 1,302 individuals with airway obstruction selected from the ongoing Copenhagen City Heart Study.

MEASUREMENTS AND MAIN RESULTS

We measured serum CRP at baseline, and recorded COPD admissions and deaths as outcomes. During follow-up, 185 (14%) individuals were hospitalized due to COPD and 83 (6%) died of COPD. Incidences of COPD hospitalization and COPD death were increased in individuals with baseline CRP > 3 mg/L versus < or = 3 mg/L (log rank: p < 0.001). After adjusting for sex, age, FEV(1)% predicted, tobacco consumption, and ischemic heart disease, the hazard ratios for hospitalization and death due to COPD were increased at 1.4 (95% confidence interval, 1.0-2.0) and 2.2 (1.2-3.9) in individuals with baseline CRP > 3 mg/L versus < or = 3 mg/L. After close matching for FEV(1)% predicted and adjusting for potential confounders, baseline CRP was, on average, increased by 1.2 mg/L (analysis of variance: p = 0.002) and 4.1 mg/L (p = 0.001) in those who were subsequently hospitalized or died of COPD, respectively. The absolute 10-yr risks for COPD hospitalization and death in individuals with CRP above 3 mg/L were 54 and 57%, respectively, among those older than 70 yr with a tobacco consumption above 15 g/d and an FEV(1)% predicted of less than 50.

CONCLUSIONS

CRP is a strong and independent predictor of future COPD outcomes in individuals with airway obstruction.

Association of bronchial hyperresponsiveness and lung function with C-reactive protein (CRP): a population based study

BACKGROUND

C-reactive protein (CRP), a marker of systemic inflammation, is a powerful predictor of adverse cardiovascular events. Respiratory impairment is also associated with cardiovascular risk. Although some studies have found an inverse relationship between lung function and markers of systemic inflammation, only one study has reported a relationship between lung function and CRP levels. In contrast, little is known about the relationship between bronchial hyperresponsiveness (BHR) and systemic inflammation. The association between lung function and CRP and between BHR and CRP has been investigated.

METHODS

As part of the European Community Respiratory Health Survey follow up study serum CRP levels, forced expiratory volume in 1 second (FEV(1)), and BHR to methacholine (>/=20% decrease in FEV(1) to <4 mg methacholine) were measured in 259 adults aged 28-56 years free of cardiovascular disease or respiratory infection.

RESULTS

Mean (SD) FEV(1) (adjusted for age, sex, height, and smoking status) was lower in subjects with a high CRP level (high tertile) (3.29 (0.44) l/s v 3.50 (0.44) l/s; p<0.001) and BHR was more frequent (41.9% v 24.9%; p = 0.005) than in subjects with lower CRP levels (low+middle tertiles). Similar results were obtained when the potential confounding factors were taken into account. Similar patterns of results were found in non-smokers and in non-asthmatic subjects.

CONCLUSIONS

Increased CRP levels are strongly and independently associated with respiratory impairment and more frequent BHR. These results suggest that both respiratory impairment and BHR are associated with a systemic inflammatory process.