Effect Of Acute Resistance Exercise On Serum Kallistatin And Plasminogen Activator Inhibitor-1 Levels

Kallistatin (KAL) and plasminogen activator inhibitor type-1 (PAI-1) are serine proteinase inhibitors (SERPINs) with various roles including anticoagulation, antioxidation, and vasodilation. Little research exists to describe the effect of an acute resistance exercise bout on the circulating concentration of these proteins in serum. Since resistance exercise is a known inducer of homeostasis disturbance and oxidative stress, it is possible that SERPIN protein expression may be acutely altered as a result. PURPOSE: To determine the effect of an acute resistance exercise bout on serum concentration of KAL and PAI-1 in previously resistance-trained participants. METHODS: Sixteen resistance-trained subjects (6F, 10 M; age 21.6 ± 2.2 yr) performed a full-body resistance exercise bout (3 sets of 6 exercises using 60-80% of one-repetition maximum). Before exercise and 60 min post-exercise, participants consumed a standardized meal (7.2 mL/kg of a lactose-free chocolate milk drink). Blood samples were obtained 30 min after the first meal (Pre-Ex), immediate post-exercise (ImmPost-Ex), 90 min post-exercise (90Post-Ex) and 180 min post-exercise (180Post-Ex). Samples clotted for 30 min before removal and storage of serum at -80 °C. Serum KAL and PAI-1 were measured using ELISA assays on an automated ELISA system. Data were analyzed using separate 2x4 (Sex x Time) two-way mixed-model repeated-measures ANOVA for each variable. One-way repeated-measures ANOVA with Tukey’s post-hoc tests were used to determine significant differences within the main effect of Time. RESULTS: No significant interactions (Sex x Time) or Sex differences were observed for KAL or PAI-1 (all p > 0.05). A significant main effect for Time was observed for KAL (p = 0.05) and PAI-1 (p = 0.01). Post-hoc testing revealed no significant differences between time points for KAL. Serum PAI-1 levels were increased ImmPost-EX compared with Pre-Ex (146.4 ± 39.5 ng/mL vs. 114.2 ± 20.8 ng/mL, p < 0.01). CONCLUSION: Serum PAI-1 was significantly increased ImmPost-Ex compared with Pre-Ex. Further research is needed to determine the functional significance of PAI-1 alterations following acute resistance exercise.