Iodothyronine deiodinases in patients with stable chronic obstructive pulmonary disease - preliminary results.

Background: Different immune/inflammatory molecules play key roles in the development of inflammatory diseases, including chronic obstructive pulmonary disease (COPD). Thyroid hormones (THs) participate in immune/inflammatory reactions and may play a role in COPD. The main TH metabolism reactions are dependent on iodothyronine deiodinase (DIO). Accumulating evidence also supports the role of cytokines in TH metabolism-related factors. This cross-sectional, observational study investigated the levels of DIO and proinflammatory cytokines and their correlations with stable COPD.

Methods: A total of 55 participants, comprising 25 patients diagnosed with stable COPD and 30 control patients, were enrolled in this study. Cytokine and DIO levels were measured using commercially available human enzyme-linked immunosorbent assay (ELISA) kits from R&D Systems and My BioSource.

Results: Increased levels of DIO1-3 and interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-ɑ, and interferon (IFN)-ɣ were found. Correlation analysis revealed several significant correlations, including interdependence between DIO and cytokine levels, with strong correlations between DIO2 and IFN-ɣ levels and an association between the above protein levels and clinical data. The levels of DIO 1-3 and cytokines (IL-6, TNF-α, and IFN-γ) all showed a positive relationship with COPD relative risk, suggesting that higher levels of DIO and cytokines may influence COPD biology.

Conclusions: Findings from our novel study indicate that DIO and proinflammatory cytokines are possibly involved in the mechanisms underlying processes related to COPD, including immune-endocrine interaction. These can be discussed for further evaluation in COPD-related studies with more precise diagnostic and therapeutic monitoring of all confounding factors and a larger cohort.