Short-term blackcurrant extract consumption modulates exercise-induced oxidative stress and lipopolysaccharide-stimulated inflammatory responses.

Exercise-induced oxidative stress is instrumental in achieving the health benefits from regular exercise. Therefore, inappropriate use of fruit-derived products (commonly applied as prophalytic antioxidants) may counteract the positive effects of exercise. Using human exercise and cellular models we found that 1) blackcurrant supplementation suppressed exercise-induced oxidative stress, e.g., plasma carbonyls (0.9 +/- 0.1 vs. 0.6 +/- 0.1 nmol/mg protein, placebo vs. blackcurrant), and 2) preincubation of THP-1 cells with an anthocyanin-rich blackcurrant extract inhibited LPS-stimulated cytokine secretion [TNF-alpha (16,453 +/- 322 vs. 10,941 +/- 82 pg/ml, control vs. extract, P < 0.05) and IL-6 (476 +/- 14 vs. 326 +/- 32 pg/ml, control vs. extract, P < 0.05)] and NF-kappaB activation. In addition to its antioxidant and anti-inflammatory properties, we found that postexercise plasma collected after blackcurrant supplementation enhanced the differential temporal LPS-stimulated inflammatory response in THP-1 cells, resulting in an early suppression of TNF-alpha (1,741 +/- 32 vs. 1,312 +/- 42 pg/ml, placebo vs. blackcurrant, P < 0.05) and IL-6 (44 +/- 5 vs. 36 +/- 3 pg/ml, placebo vs. blackcurrant, P < 0.05) secretion after 24 h. Furthermore, by using an oxidative stress cell model, we found that preincubation of THP-1 cells with hydrogen peroxide (H(2)O(2)) prior to extract exposure caused a greater suppression of LPS-stimulated cytokine secretion after 24 h, which was not evident when cells were simultaneously incubated with H(2)O(2) and the extract. In summary, our findings support the concept that consumption of blackcurrant anthocyanins alleviate oxidative stress, and may, if given at the appropriate amount and time, complement the ability of exercise to enhance immune responsiveness to potential pathogens.

Exercise-induced elevation in plasma oxidative generating capability augments the temporal inflammatory response stimulated by lipopolysaccharide.

Prolonged oxidative stress is detrimental to health; however, transient oxidative stress may improve immune capability. We examined whether exercise-induced increases in the plasma oxidative generating capability enhance immune responsiveness to potential pathogens. Twelve individuals underwent a 30-min row and pre and post-exercise bloods were collected for oxidative stress and immune assessment. We found that exercise induced a transient increase in plasma carbonyls (3.2-5.3 nmol/mg protein) and creatine kinase activity (0.5-1.2 absorbance/min/mg protein) and that lipopolysaccharide (LPS) stimulation (0.5-24 h) of pre- and post-exercise blood augmented temporal tumour necrosis factor-alpha (TNFalpha) secretion. Further characterisation of plasma using a modified dihydro-2',7'-dichlorohydrofluorescein (DCF) assay revealed that addition of a sub-threshold of hydrogen peroxide to post-exercise (and not pre-exercise) plasma caused a sixfold increase in the radical oxygen species (ROS) generating capability after 15 min (555 +/- 131 to 3607 +/- 488 change in fluorescent intensity [DeltaFI]), which was inhibited using 60 mM N-acetyl-L: -cysteine (920 +/- 154 DeltaFI). Furthermore, cell experiments revealed that LPS stimulation of either THP-1 cells pre-incubated with post-exercise plasma or peripheral blood mononuclear cells pre-treated with pro-oxidants, modulated the temporal secretion of key cytokines that regulate the initiation, progression and resolution of an inflammatory response. These results indicate that exercise-induced changes in plasma parameters (e.g. oxidative generating capability-dependent or independent of inflammatory mediators) augment the temporal LPS response and support the notion that repeated transient oxidative stress (such as that induced by regular exercise) is important for a "healthy" immune system.

Environmental interactions of Sulphlex pavement.

Sulphlex, a mixture of elemental sulfur and plasticizers, has been considered for use as an asphalt substitute in road construction. Because this material contains substantial quantities of elemental sulfur, it is a potential substrate for growth of sulfur-oxidising bacteria. Experiments, performed to determine the susceptibility of Sulphlex in Sulphlex-containing media to degradation by Thiobacillus thiooxidans, resulted in breakdown of the Sulphlex material and concomitant production of acid. In concurrent studies, plants were grown in Sulphlex-amended soils. These plants exhibited higher sulfur content and reduced productivity as compared with plants grown in unamended soils, indicating that Sulphlex was being broken down in the soil and that the breakdown products were apparently having a detrimental effect on plant productivity. These experiments indicate that naturally occurring sulfur-oxidising bacteria have the potential to break down Sulphlex paving material, resulting in adverse effects on both the structural integrity of the pavement and the local environment.