Altered serum levels of type I collagen turnover indicators accompanied by IL-6 and IL-8 release in stable COPD

Abstract

Background

COPD, characterized by chronic inflammation and airway remodeling, has significant pathological alterations in composition and deposition of the extracellular matrix. The expression of procollagen 1 C-terminal peptide (PICP) and collagen type 1 C-terminal telopeptide (ICTP), two major by-products in the synthesis and degradation of collagen, was shown to be positively correlated with inflammatory mediator levels in previous studies.

Purpose

In this study, we investigated whether the serum concentrations of PICP and ICTP were associated with the inflammation level for patients with stable COPD.

Patients and methods

We collected serum samples from 25 control subjects and 20 patients with stable COPD from December 2011 to October 2012 in Shanghai Zhongshan Hospital and Shanghai Dahua Hospital. We determined concentrations of PICP, ICTP, C-reactive protein (CRP), IL-6, IL-8, and tumor necrosis factor (TNF)-α by using enzyme-linked immunosorbent assay methods.

Results

Demographic characteristics were comparable between the two groups. In patients with stable COPD, serum levels of CRP, IL-6, IL-8, and TNF-α were all elevated compared to control subjects, but only changes of IL-6 achieved statistical significance. Serum concentration of PICP was significantly elevated in patients with COPD, and level of ICTP was slightly decreased. Moreover, serum concentrations of PICP were positively correlated with the levels of both IL-6 and IL-8.

Conclusion

The increased levels of serum PICP in COPD might indicate the condition of airway remodeling, and IL-6 and/or IL-8 might play an important role in stimulating collagen synthesis.

Keywords:

• chronic obstructive pulmonary disease
• COPD
• procollagen type I C-terminal peptide
• PICP
• C-terminal telopeptide of type I collagen
• ICTP
• interleukin-6
• IL-6
• interleukin-8
• IL-8

Acknowledgments

This study was supported by the National Key R&D Program of China (grant nos 2017YFC1309303 and 2017YFC1309300) and the National Natural Science Foundation of China (grant no 81670030).

Author contributions

All authors contributed to data analysis, drafting and revising the article, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.