Increasing circulating levels of Tenascin C in response to the Wingate anaerobic test

Tenascin C (TNC) is a large extracellular matrix glycoprotein. It is involved in development and upregulated both during tissue repair and in several pathological conditions, including cardiovascular disease. Extracellular matrix proteins play a role in promoting exercise responses, leading to adaptation, regeneration, and repair. The main goal of this study was to investigate whether a short anaerobic effort leads to increased levels of TNC in serum.

Thirty-nine healthy men performed a Wingate test followed by a muscle biopsy. Myoblasts were isolated from the muscle biopsies and differentiated to myotubes ex vivo. TNC RNA was quantified in the biopsies, myotubes and myoblasts using RNA sequencing. Blood samples were drawn before and 5 min after the Wingate test. Serum TNC levels were measured using enzyme-linked immunosorbent assay.

After the Wingate test, serum TNC increased on average by 23% [15-33], median [interquartile range]; P_Wilcoxon  < 0.0001. This increase is correlated with peak power output and power drop, but not with VO_2max . TNC RNA expression is higher in myoblasts and myotubes compared to skeletal muscle tissue.

TNC is secreted systemically as a response to the Wingate anaerobic test in healthy males. The response was positively correlated with peak power and power drop, but not with VO_2max which implicates a relation to mechanical strain and/or blood flow. With higher expression in undifferentiated myoblast cells than muscle tissue, it is likely that TNC plays a role in muscle tissue remodelling in humans. Our findings open for research on how TNC contributes to exercise adaptation.