Evaluation of TGF-β isoforms based on selected clinical parameters in asthmatic patients

Introduction:
The transforming growth factor β (TGF-β) has attracted particular attention from researchers in the context of the pathogenesis and development of asthma and allergic diseases. Undoubtedly, TGF-β is one of the main cytokines involved in mediating inflammation and bronchial remodeling. It stimulates fibroblasts and myofibroblasts, and regulates processes of extracellular matrix remodeling, thus contributing to fibrosis and bronchial remodeling. In long-term inflammation, the airways become stiffened and airflow is impaired, which is sometimes reflected by lower values of spirometric parameters. What may also be observed in aging organs is intensified fibrotic processes.

Aim:
To evaluate the correlation between concentrations of all the TGF-β 1-3 isoforms and selected clinical parameters, including pulmonary function indices assessed by spirometry.

Material and methods:
The study included 41 asthmatic patients and 28 non-asthmatic volunteers recruited from the Department of Allergology and the Allergy and Pulmonology Outpatient Clinic of N. Barlicki University Teaching Hospital No. 1 in Lodz. The participants underwent a full medical examination and spirometry, and blood samples were collected from them for serum TGF-β levels. Individual isoforms of TGF-β1, TGF-β2 and TGF-β3 were determined by ELISA. The data obtained were then subjected to statistical analysis using the Student’s t-test, Mann-Whitney U-test, Fisher’s t-test and Pearson’s correlation.

Results:
The obtained results show significantly increased TGF-β1 and TGF-β2 levels among the elderly, both diseased and non-asthmatic individuals. Additionally, higher TGF-β1 and TGF-β2 concentrations correlate significantly with a decreased FEV1%/FVC ratio, while TGF-β2 alone also correlates negatively with FEV1 and FVC values. The TGF-β1 and TGF-β2 isoforms have been shown to be associated with the pathogenesis of asthma. Expression of TGF-β1 and TGF-β2 increases with age. Higher concentrations of TGF-β1 and TGF-β2 significantly translate into worsening spirometric values.

Conclusions:
It is worth continuing research on TGF-β as a potential marker of remodeling in asthma.