Capsular contracture (CC) is one of the most common post-operative complications among breast-implant associated infections. However, the mechanisms that lead to CC are still poorly understood. Therefore, we employed depletion of high-abundance plasma proteins followed by TMT-based quantitative mass spectrometry (MS) to construct the plasma proteome in healthy controls and patients with biofilm-related breast-implant CC to explore disease-associated alterations of plasma proteins.
Plasma from each patient (10 healthy control, 10 CC) was processed for the depletion of high-abundant proteins using immune affinity-based depletion method (MARS-14) to improve the depth of detection in plasma samples. Protein extraction, fractionation, reduction, alkylation, digestion, and 10-plex Tandem Mass Tag (TMT) labeling steps were performed, respectively. TMT-based MS was performed, and protein identification and relative quantitation of protein levels were analysed using Proteome Discoverer (version 2.1). Statistical analysis was done using the TMTPrePro R package.
A total of 450 proteins were identified from these samples. Among the significant differentially expressed proteins tropomyosin alpha-4, talin-1, transferrin receptor protein 1, lipopolysaccharide-binding and fibrinogen alpha chain were exclusively upregulated whereas cartilage intermediate layer protein 2, bone marrow proteoglycan, complement component C7, neural cell adhesion molecule 2, etc were downregulated in the breast implant CC patients as compared to healthy controls. Interestingly, we found a correlation with the significant upregulation of tropomyosin alpha-4, increased myofibroblast activity, and the regulatory mechanism by TGF-β which demonstrated a correlation with bacterial biofilms. Further pathway analysis revealed an inflammatory response, focal adhesion, platelet activation, complement and coagulation cascades, as enriched pathways identified in this study.
This is the first report using high throughput TMT-based MS in the plasma of patients with breast implant CC. The identified differentially expressed proteins has the potential to provide important information for future mechanism studies and in the development of breast implant CC biomarker/s.