Vitamin D May Link Bronchiectasis and COPD

Vitamin D May Link Bronchiectasis and COPD

A large project underway at University Hospital of Leuven, headed by principal investigator Wim Janssens, MD, PhD, is identifying the mechanism behind bronchiectasis development in patients with chronic obstructive pulmonary disorder (COPD). These two unique, yet similar, diseases may be connected by vitamin D and Aspergillus fumigatus infection. To begin testing this hypothesis, a currently recruiting observational clinical trial, “Detection of Aspergillus Fumigatus and Sensitization in COPD Patients with Bronchiectasis vs without Bronciectasis,” will examine 100 COPD patients and identify differences between those with bronchiectasis and those without bronchiectasis.

The trial was initiated January 5 and will be conducted at a single center, University Hospital of Leuven, in Belgium. Enrolled patients must have a clinical diagnosis of COPD and a smoking history of at least 10 pack-years. No other respiratory diseases will be accepted, and patients cannot have active mycobacterial disease. All patients who enter the emergency department due to an acute COPD exacerbation will be evaluated for these and other criteria.

To gather data, clinicians will induce sputum production from patients after ensuring patient forced expiratory volume in one second (FEV1) is adequate (>30%) enough to be considered safe. Samples of sputum will be evaluated for the presence of A. fumigatus.

Building upon data from sputum samples, data from a skin prick test will be used to diagnose IgE-mediated (antibody-mediated) allergic disease. Clinicians will apply an extract of A. fumigatus on the forearms of patients before pricking the skin with a single-head metal lancet. This will allow researchers to determine cutaneous reactivity to A. fumigatus, also known as sensitazation, which is defined by a resultant bump, or wheal, with a diameter greater than three millimeters.

Finally, clinicians will use the Medical Research Council Scale, COPD Assessment Test, and Saint George’s Respiratory Questionnaire to determine severity of patient symptoms and quality of life. All data will be compared between the two groups defined by the presence or absence of bronchiectasis.

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These data, once compiled, will be used in future evaluations of the researchers’ hypothesis: “We suspect that [development of bronchiectasis in COPD] is controlled by vitamin D and it fails by suppression of the vitamin D receptor by A. fumigatus,” stated the researchers at University Hospital of Leuven. Previous reports have shown that “Vitamin D-binding Protein Contributes to COPD by Activation of Alveolar Macrophages,” indicating that a link between vitamin D, as a result of vitamin D-binding protein genetic polymorphisms, and COPD already exists. The present study may extend this link to include bronchiectasis, as well.

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