New Zealand blackcurrant extract modulates the heat shock response in men during exercise in hot ambient conditions.

Abstract

To determine if 7d of New Zealand blackcurrant (NZBC) extract alters the heat shock, inflammatory and apoptotic response during prolonged exertional-heat stress. Ten men (Age: 29 ± 2years, Stature: 1.82 ± 0.02m, Mass: 80.3 ± 2.7kg, V̇O2max: 56 ± 2mL·kg-1·min-1) ingested two capsules of CurraNZ™ (NZBC extract: 210mg anthocyanins·day-1) or PLACEBO for 7d prior to 1h treadmill run (65% V̇O2max) in hot ambient conditions (34°C/40% RH). Blood samples were collected before (Pre), immediately after (Post), 1h after (1-Post), and 4h after (4-Post) exercise. Heat shock proteins (HSP90, HSP70, HSP32) were measured in plasma. HSP and protein markers of inflammatory capacity (TLR4, NF-κB) and apoptosis (BAX/BCL-2, Caspase 9) were measured in peripheral blood mononuclear cells (PBMC). eHSP32 was elevated at baseline in NZBC(+ 31%; p < 0.001). In PLACEBO HSP32 content in PBMC was elevated at 4-Post(+ 98%; p = 0.002), whereas in NZBC it fell at Post(-45%; p = 0.030) and 1-Post(-48%; p = 0.026). eHSP70 was increased at Post in PLACEBO(+ 55.6%, p = 0.001) and NZBC (+ 50.7%, p = 0.010). eHSP90 was increased at Post(+ 77.9%, p < 0.001) and 1-Post(+ 73.2%, p < 0.001) in PLACEBO, with similar increases being shown in NZBC (+ 49.0%, p = 0.006 and + 66.2%, p = 0.001; respectively). TLR4 and NF-κB were both elevated in NZBC at PRE(+ 54%, p = 0.003 and + 57%, p = 0.004; respectively). Main effects of study condition were also shown for BAX/BCL-2(p = 0.025) and Caspase 9 (p = 0.043); both were higher in NZBC. 7d of NZBC extract supplementation increased eHSP32 and PBMC HSP32 content. It also increased inflammatory and apoptotic markers in PBMC, suggesting that NZBCsupports the putative inflammatory response that accompanies exertional-heat stress.