Bovine colostrum has been shown to influence the cytokine production of bovine leukocytes. However, it remains unknown whether processed bovine colostrum, a supplement popular among athletes to enhance immune function, is able to modulate cytokine secretion of human lymphocytes and monocytes. The aim of this investigation was to determine the influence of a commercially available bovine colostrum protein concentrate (CPC) to stimulate cytokine production by human peripheral blood mononuclear cells (PBMCs). Blood was sampled from four healthy male endurance athletes who had abstained from exercise for 48 h. PBMCs were separated and cultured with bovine CPC concentrations of 0 (control), 1.25, 2.5, and 5% with and without lipopolysaccharide (LPS) (3 microg/mL) and phytohemagglutinin (PHA) (2.5 microg/mL). Cell supernatants were collected at 6 and 24 h of culture for the determination of tumor necrosis factor (TNF), interferon (IFN)-gamma, interleukin (IL)-10, IL-6, IL-4, and IL-2 concentrations. Bovine CPC significantly stimulated the release of IFN-gamma, IL-10, and IL-2 (p < 0.03). The addition of LPS to PBMCs cocultured with bovine CPC significantly stimulated the release of IL-2 and inhibited the early release of TNF, IL-6, and IL-4 (p < 0.02). Phytohemagglutinin stimulation in combination with bovine CPC significantly increased the secretion of IL-10 and IL-2 at 6 h of culture and inhibited IFN-gamma and TNF (p < 0.05). This data show that a commercial bovine CPC is able to modulate in vitro cytokine production of human PBMCs. Alterations in cytokine secretion may be a potential mechanism for reported benefits associated with supplementation.

We examined the influence of 3 consecutive days of high-intensity cycling on blood and urinary markers of oxidative stress. Eight highly-trained male cyclists (VO_2 max76 ± 4 mL·kg^–1·min^–1; mean ± SD) completed an interval session (9 exercise bouts lasting 30 s each, at 150% peak power output) on day 1, followed by 2 laboratory-simulated 30 km time trials on days 2 and 3. The cyclists also completed a submaximal exercise trial matched to the interval session for oxygen consumption. Blood was collected pre- and post-exercise for the determination of malondialdehyde (MDA), total antioxidant status (TAS), vitamin E, and the antioxidant enzyme activity of superoxide dismutase and glutathione peroxidase, while urine was collected for the determination of allantoin. There were significant increases in plasma MDA concentrations (p < 0.01), plasma TAS (p < 0.01), and urinary allantoin excretion (p < 0.01) following the high-intensity interval session on day 1, whereas plasma vitamin E concentration significantly decreased (p = 0.028). Post-exercise changes in plasma MDA (p = 0.036), TAS concentrations (p = 0.039), and urinary allantoin excretion (p = 0.031) were all significantly attenuated over the 3 consecutive days of exercise, whereas resting plasma TAS concentration was elevated. There were no significant changes in plasma MDA, TAS, or allantoin excretion following submaximal exercise and there were no significant changes in antioxidant enzyme activity over consecutive days of exercise or following submaximal exercise. Consecutive days of high-intensity exercise enhanced resting plasma TAS concentration and reduced the post-exercise increase in plasma MDA concentrations.

Immunosuppressants have been associated with increased cardiovascular disease risk. We determined the effects of calcineurin and mammalian target of rapamycin (mTOR) inhibitor administration on endothelial dysfunction and associated inflammation and oxidative stress in adult rats. Cyclosporine A (low and high dose), sirolimus, tacrolimus, everolimus and placebo were administered to 8-week-old male Wistar rats for 10 consecutive days. Aortic vascular endothelial and smooth muscle function were assessed ex vivo in organ baths. Maximal aortic contraction to noradrenaline in sirolimus-treated rats was significantly greater than cyclosporine groups, everolimus and placebo, whereas endothelial-dependent relaxation was significantly impaired with cyclosporine and tacrolimus compared with everolimus. Endothelial-independent relaxation was impaired in tacrolimus-treated rats compared with low dose cyclosporine, everolimus and sirolimus. Sirolimus was associated with a reduction in plasma interleukin (IL)-1β and tumour necrosis factor (TNF)-α and higher levels of catalase and total antioxidant status. In nontransplanted rats, vascular dysfunction was evident following administration of cyclosporine A, sirolimus and tacrolimus, whereas everolimus did not compromise aortic endothelial or smooth muscle function. At the doses administered in this model, the immunosuppressants exerted varying effects on vascular function.