New Zealand Blackcurrant Extract Increases Circulating Hsp32 And Hsp90α But Doesn’T Affect Circulating Hsp72

Abstract

Extracellular heat shock protein 72 (eHSP72) acts as an inflammatory molecule, inducing cytokine production in immune cells, whereas HSP90α is implicit in recovery and adaptation to cellular stress. Heme oxygenase-1 (eHSP32) protects the vasculature and suppresses inflammation. Each are elevated following exertional heat stress. Polyphenols are proposed to have anti-inflammatory properties, so may affect eHSP responses to exercise. PURPOSE: To determine the effects of 7-days supplementation with New Zealand blackcurrant (NZBC) extract on eHSP72, eHSP90α, and eHSP32 before and after exertional heat stress. METHODS: In a randomized double-blind design, 12 men (Age: 28±6 years, stature: 1.81±0.07 m, mass: 80.5±9.8 kg, VO2max: 55.6±6.0 mL.kg-1.min-1) completed 2 trials. Participants ingested 2x300 mg.day-1 capsules of CurraNZ™ (each containing 105 mg anthocyanin) or a visually matched placebo for 7 days (washout 14 days). On day 7, participants ran 60 minutes at 65%VO2max in hot ambient conditions (34°C and 40% relative humidity). eHSP72, eHSP90a, and eHSP32 were measured in EDTA plasma at rest and 20 and 60 minutes after exercise. RESULTS: Post exercise eHSP72 concentrations were elevated after the placebo [by 1.98 ng.mL-1 (95% CI: 0.65 - 3.33 ng.mL-1)] and NZBC trials [by 1.59 ng.mL-1 (95% CI: 0.03 - 3.15 ng.mL-1)] and remained elevated 60 minutes after exercise [Placebo: by 0.68 ng.mL-1 (95% CI: -0.07 - 1.46 ng.mL-1); NZBC by 0.51 ng.mL-1 (95% CI: -0.37 - 1.40 ng.mL-1)]. Basal eHSP90α concentration was increased following NZBC supplementation [by 5.60 ng.mL-1 (1.85 - 9.51 ng.mL-1), trial x time interaction, F = 3.57, p = 0.046, np2 = 0.25), and were elevated at 20 and 60 minutes post exercise in both conditions. Similarly, basal eHSP32 was elevated after NZBC supplementation [by 3.9 ng.mL-1 (95% CI: 0.37 - 7.42 ng.mL-1), trial x time interaction F = 5.62, p = 0.01, np2 = 0.34), but were not altered at 20 or 60 minutes after heat stress in either condition. CONCLUSION: We present moderate evidence to support that 7 days of NZBC extract supplementation increases basal eHSP32 and eHSP90a, with no effect on eHSP72 before or after exercise. Further research is required to determine the functional relevance of these increases. Acknowledgement: We thank Health Currancy Ltd (UK) and CurraNZ (NZ) for supplements.