Correlates and assessment of excess cardiovascular risk in bronchiectasis.

Patients with bronchiectasis are at increased risk of cardiovascular disease. We aimed to identify factors associated with elevated cardiovascular risk in bronchiectasis, measured using aortic stiffness and cardiac biomarkers. In addition, we sought to compare these direct measures against calculated QRISK2 scores.Aortic stiffness, cardiac biomarkers and systemic inflammation were measured in 101 adults with stable bronchiectasis. In addition, clinical and demographic data were collected to allow calculation of QRISK2 score and the bronchiectasis severity index (BSI) for each patient.The BSI score correlated with measured cardiovascular risk assessments, partly due to greater exacerbation frequency and lower forced expiratory volume in 1 s. Pulse-wave velocity was significantly higher in frequent exacerbators (≥3 events·year-1) than infrequent exacerbators (<3 events·year-1; 10.5 versus 9.2 m·s-1, p=0.01). In addition, frequent exacerbators had elevated serum C-reactive protein concentration, suggesting increased systemic inflammation (4.8 versus 2.2 mg·L-1, p=0.005). QRISK2 systematically underestimated cardiovascular risk in this population (median change in relative risk 1.29). Underestimation was associated with frequent exacerbations and male sex.Patients with bronchiectasis have greater cardiovascular risk than published reference populations. Excess cardiovascular risk is associated with exacerbation frequency and impaired lung function. Cardiovascular risk assessment in bronchiectasis should be individualised, as calculation tools are likely to underestimate the risk in this population.

The heterogeneity of systemic inflammation in bronchiectasis.

BACKGROUND: Systemic inflammation in bronchiectasis is poorly studied in relation to aetiology and severity. We hypothesized that molecular patterns of inflammation may define particular aetiology and severity groups in bronchiectasis. METHOD: We assayed blood concentrations of 31 proteins from 90 bronchiectasis patients (derivation cohort) and conducted PCA to examine relationships between these markers, disease aetiology and severity. Key results were validated in two separate cohorts of 97 and 79 patients from other centres. RESULTS: There was significant heterogeneity in protein concentrations across the derivation population. Increasing severity of bronchiectasis (BSI) was associated with increasing fibrinogen (rho = 0.34, p = 0.001 -validated in a second cohort), and higher fibrinogen was associated with worse lung function, Pseudomonas colonisation and impaired health-status. There were generally similar patterns of inflammation in patients with idiopathic and post-infectious disease. However, patients with primary immunodeficiency had exaggerated IL-17 responses, validated in a second cohort (n = 79, immunodeficient 12.82 pg/ml versus idiopathic/post-infectious 4.95 pg/ml, p = 0.001), and thus IL-17 discriminated primary immunodeficiency from other aetiologies (AUC 0.769 (95%CI 0.661-0.877)). CONCLUSION: Bronchiectasis is associated with heterogeneity of systemic inflammatory proteins not adequately explained by differences in disease aetiology or severity. More severe disease is associated with enhanced acute-phase responses. Plasma fibrinogen was associated with bronchiectasis severity in two cohorts, Pseudomonas colonisation and health status, and offers potential as a useful biomarker.

Deficiency Mutations of Alpha-1 Antitrypsin. Effects on Folding, Function, and Polymerization.

Misfolding, polymerization, and defective secretion of functional alpha-1 antitrypsin underlies the predisposition to severe liver and lung disease in alpha-1 antitrypsin deficiency. We have identified a novel (Ala336Pro, Baghdad) deficiency variant and characterized it relative to the wild-type (M) and Glu342Lys (Z) alleles. The index case is a homozygous individual of consanguineous parentage, with levels of circulating alpha-1 antitrypsin in the moderate deficiency range, but is a biochemical phenotype that could not be classified by standard methods. The majority of the protein was present as functionally inactive polymer, and the remaining monomer was 37% active relative to the wild-type protein. These factors combined indicate an 85 to 95% functional deficiency, similar to that seen with ZZ homozygotes. Biochemical, biophysical, and computational studies further defined the molecular basis of this deficiency. These studies demonstrated that native Ala336Pro alpha-1 antitrypsin could populate the polymerogenic intermediate-and therefore polymerize-more readily than either wild-type alpha-1 antitrypsin or the Z variant. In contrast, folding was far less impaired in Ala336Pro alpha-1 antitrypsin than in the Z variant. The data are consistent with a disparate contribution by the "breach" region and "shutter" region of strand 5A to folding and polymerization mechanisms. Moreover, the findings demonstrate that, in these variants, folding efficiency does not correlate directly with the tendency to polymerize in vitro or in vivo. They therefore differentiate generalized misfolding from polymerization tendencies in missense variants of alpha-1 antitrypsin. Clinically, they further support the need to quantify loss-of-function in alpha-1 antitrypsin deficiency to individualize patient care.