Functional Characteristics of the Crosstalk Between Vocal Fold Fibroblasts and Macrophages-The Role of Vibration in Vocal Fold Inflammation.

Abstract

Objectives: This in vitro study investigated the interaction between human vocal fold fibroblasts (hVFF) and macrophages under the influence of cigarette smoke extract (CSE) and vibration as potential regulators of vocal fold (VF) inflammation.

Study design: Experimental in vitro pilot study.

Methods: Immortalized hVFF were cultured in flexible-bottomed cell culture plates, treated with CSE, and subjected to static or dynamic conditions in a phonomimetic bioreactor. For coculture, unstimulated or lipopolysaccharide/IFNγ-stimulated THP-1 (human leukemia monocytic cell line) macrophages were added in inserts for a final 24 hours of vibration period. We measured messenger ribonucleic acid (mRNA) (quantitative polymerase chain reaction [qPCR]) and protein levels (Western Blot, ELISA, and LUMINEX®) of hVFF and analyzed the results using two- and three-way ANOVA with post hoc tests.

Results: Under inflammatory stimulation, we observed a reduction of collagen (COL) type 1A1, 1A2, and 3A1, and increased gene expression of COL4A1, matrix metallopeptidase 2, and vascular endothelial growth factor A in hVFF. Additionally, the pro-inflammatory markers cyclooxygenase (COX) 1 and 2, interleukin (IL) 1β, IL-6, and IL-8 were upregulated. CSE increased COX1 and COX2 levels, whereas vibration reduced CSE-induced increases of COL4A1 and COX2 in pro-inflammatory stimulated hVFF.

Conclusion: This study indicates that vibration may mitigate CSE-induced inflammatory damage in the hVFF, thereby offering new insights into the cellular crosstalk that underlies the pathophysiology of VF inflammation in smoking-related voice disorders.