Carbohydrate supplementation affects blood granulocyte and monocyte trafficking but not function after 2.5 h or running.

This randomized, double-blind, placebo-controlled study was designed to determine the influence of carbohydrate supplementation on the granulocyte and monocyte response to 2.5 h of high-intensity running [76.7 +/- 0.4% of maximal oxygen consumption (VO2max)]. Thirty experienced marathon runners (VO2max 53.4 +/- 1.0 mL.kg-1.min-1, age 41.5 +/- 1.4 y) were randomly assigned to carbohydrate-supplement (n = 17) and placebo (n = 13) groups. Subjects rested for 10-15 min before a blood sample was taken at 0715, and then ingested 0.75 L carbohydrate beverage or placebo. At 0730 subjects began running at 75-80% of VO2max for 2.5 h, and drank 0.25 L carbohydrate or placebo fluid every 15 min. Immediately after the 2.5-h run (1000), another blood sample was taken, followed by 1.5-h, 3-h, and 6-h recovery samples. Carbohydrate supplementation had a significant effect compared with placebo on the pattern of change in plasma glucose and cortisol, and the blood concentration of neutrophils (F[14, 112] = 5.13, P = 0.001) and monocytes (F[14, 112] = 4.78, P = 0.001), but not on blood granulocyte and monocyte phagocytosis or oxidative burst activity after 2.5 h of intensive running.

Effects of mode and carbohydrate on the granulocyte and monocyte response to intensive, prolonged exercise.

The influence of exercise mode and 6% carbohydrate (C) vs. placebo (P) beverage ingestion on granulocyte and monocyte phagocytosis and oxidative burst activity (GMPOB) after prolonged and intensive exertion was measured in 10 triathletes. The triathletes acted as their own controls and ran or cycled for 2.5 h at approximately 75% maximal O2 uptake, ingesting C or P (4 total sessions, random order, with beverages administered in double-blind fashion). During the 2. 5-h exercise bouts, C or P (4 ml/kg) was ingested every 15 min. Five blood samples were collected (15 min before exercise, immediately after exercise, and 1.5, 3, and 6 h after exercise). The pattern of change over time for GMPOB was significantly different between C and P conditions (P

Indomethacin does not alter natural killer cell response to 2.5 h of running.

The effect of 2.5 h of treadmill running at 75.6 +/- 0.9% maximal O2 uptake (VO2max) on natural killer (NK) cell cytotoxic activity (NKCA) was investigated in 22 experienced marathon runners (VO2max 57.9 +/- 1.1 ml.kg-1.min-1, age 38.7 +/- 1.5 yr). Blood samples were taken before (0715) and immediately after exercise (1000), with three more samples taken during 6 h of recovery (1130, 1300, and 1600). Ten sedentary controls (VO2max 34.7 +/- 1.0 ml.kg-1.min-1, age 45.3 +/- 2.3 yr) sat in the laboratory during testing and had their blood sampled at the same time points. The pattern of change in NKCA over time was significantly different between groups [F(4,27) = 6.53; P = 0.001], with the runner's NKCA dropping 51-61% below preexercise levels throughout 6 h of recovery. Preincubation of blood mononuclear cells in vitro with indomethacin had no effect on the difference in pattern of change in NKCA between groups [F(4,17) = 8.59; P = 0.001] and did not attenuate the postexercise reduction in the runners. When NKCA was adjusted on a per-NK cell basis, group differences and the postexercise decline in NKCA were eliminated [F(4,80) = 0.65; P = 0.63]. Serum cortisol and plasma epinephrine in the runners were elevated relative to control subjects during recovery from exercise, but no significant correlation with changes in NK cells or NKCA was found. These data indicate that NKCA is decreased significantly during recovery from 2.5 h of running due to a numerical redistribution of NK cells.

Carbohydrate and the cytokine response to 2.5 h of running.

This randomized, double-blind, placebo-controlled study was designed to determine the influence of 6% carbohydrate (C) vs. placebo (P) beverage ingestion on cytokine responses (5 total samples over 9 h) to 2.5 h of high-intensity running (76.7 +/- 0.4% maximal O2 uptake) by 30 experienced marathon runners. For interleukin-6 (IL-6), a difference in the pattern of change between groups was found, highlighted by a greater increase in P vs. C immediately postrun (753 vs. 421%) and 1.5 h postrun (193 vs. 86%) [F(4,112) = 3.77, P = 0.006]. For interleukin-1-receptor antagonist (IL-1ra), a difference in the pattern of change between groups was found, highlighted by a greater increase in P vs. C 1.5 h postrun (231 vs. 72%) [F(2,50) = 6.38, P = 0.003]. No significant interaction effects were seen for bioactive IL-6 or IL-1 beta. The immediate postrun plasma glucose concentrations correlated negatively with those of plasma cortisol (r = -0.67, P < 0.001); postrun plasma cortisol (r = 0.70, P < 0.001) and IL-6 levels (r = 0.54, P = 0.003) correlated positively with levels of IL-1ra. Taken together, the data indicate that carbohydrate ingestion attenuates cytokine levels in the inflammatory cascade in response to heavy exertion.

Influence of obesity on immune function.

OBJECTIVE: To compare immune function in obese and nonobese subjects. DESIGN: Obese and nonobese subjects were compared cross-sectionally. To test for the influence of other factors on immunity, aerobic fitness, psychological well-being, and serum levels of glucose, triglycerides, and cholesterol were measured and included in multiple regression models to determine their comparative effects. SUBJECTS/SETTING: Community-based subjects included 116 obese women (age = 44.3 +/- 9.7 years, body mass index = 33.2 +/- 6.5) and 41 nonobese women (age = 42.2 +/- 10.9 years, body mass index = 21.2 +/- 1.9). STATISTICAL ANALYSES PERFORMED: Independent t tests, Pearson product moment correlations, and stepwise multiple regression procedures. RESULTS: Obesity was linked to elevated leukocyte and lymphocyte subset counts (except for natural killer and cytotoxic/suppressor T cells), suppressed mitogen-induced lymphocyte proliferation (an index of T- and B-cell function), higher monocyte and granulocyte phagocytosis and oxidative burst activity, and normal activity of natural killer cells. APPLICATIONS/CONCLUSIONS: These data support the contention that obesity is associated with alterations in immune function. Further research is needed to link immunosuppression with the previously reported elevated risk of infection among the obese.

Influence of mode and carbohydrate on the cytokine response to heavy exertion.

OBJECTIVE AND METHODS: This randomized, double-blind, placebo-controlled study was designed to determine the influence of exercise mode and 6% carbohydrate (C) versus placebo (P) beverage ingestion, on blood cell counts, plasma glucose, hormone, and inflammatory cytokine responses (five total samples over 9 h) to 2.5 h of high-intensity running and cycling (approximately 75% VO2max) by 10 triathletes who acted as their own controls. Statistical significance was set at P < or = 0.05. RESULTS: C relative to P ingestion (but not exercise mode) was associated with higher plasma levels of glucose and insulin, lower plasma cortisol and growth hormone, and diminished perturbation in blood immune cell counts. The pattern of change over time for interleukin (IL)-6 was significantly different between C and P conditions (P = 0.021) and between running and cycling modes (P < 0.001), with the lowest postexercise values seen in the C-cycling sessions (10.7 +/- 1.8 pg x mL(-1)) and the highest in the P-running sessions (51.6 +/- 14.2 pg x mL(-1)). The pattern of change over time between C and P conditions (but not modes) was significantly different for IL-1 receptor antagonist (P = 0.003), with values once again lowest for the C-cycling sessions (1.5 h postexercise, 301 +/- 114 pg x mL(-1)) and highest for the P-running sessions (1171 +/- 439 pg x mL(-1)). CONCLUSION: These data indicate that carbohydrate versus placebo ingestion (4 mL x kg(-1) carbohydrate or placebo every 15 min of the 2.5-h exercise bout) is associated with higher plasma glucose levels, an attenuated cortisol response, and a diminished pro- and anti-inflammatory cytokine response.

Immune response to exercise training and/or energy restriction in obese women.

PURPOSE: The effect of exercise training (five 45-min walking sessions/wk at 60-75% maximum heart rate) and/or moderate energy restriction (4.19-5.44 MJ or 1,200-1,300 kcal x d(-1)) on innate and adaptive immunity (including mitogen-stimulated lymphocyte proliferation (MSLP), natural killer cell activity (NKCA), and monocyte and granulocyte phagocytosis and oxidative burst (MGPOB) was studied in obese women (N = 91, age 45.6 +/- 1.1 yr, body mass index 33.1 +/- 0.6 kg x m(-2)) randomized to one of four groups: control (C), exercise (E), diet (D), exercise, and diet (ED). METHODS: Aerobic power, body composition, and immune function were measured in all subjects before and after a 12-wk diet intervention period, with data analyzed using a 4 x 2 repeated measures design. All subjects self-reported symptoms of sickness in health logs using a precoded checklist. Statistical significance was set at P < or = 0.05. RESULTS: Data from this study indicate that although exercise training was unrelated to any significant changes in resting immune function, the number of days with symptoms of upper respiratory tract infection (URTI) was reduced relative to subjects in the nonexercise groups (5.6 +/- 0.9 and 9.4 +/- 1.1 sickness days, respectively, P < 0.05). Energy restriction and weight loss (7.9 +/- 0.7 kg) was associated with a significant decrease in MSLP, but no change in NKCA, MGPOB, or URTI. CONCLUSION: The data are consistent the viewpoint that weight loss, even at a moderate rate, is associated with a decrease in mitogen-stimulated lymphocyte proliferation without a change in various measures of innate immunity of the blood compartment.

Immune function in marathon runners versus sedentary controls.

Marathon runners (N = 22) who had completed at least seven marathons (X +/- SEM = 23.6 +/- 5.7) and had been training for marathon race events for at least 4 yr (12.3 +/- 1.3) were compared with sedentary controls (N = 18). Although the two groups were of similar age (38.7 +/- 1.5 and 43.9 +/- 2.2 yr, respectively) and height, the marathon runners were significantly leaner and possessed a VO2max 60% higher than that of the controls. Neutrophil counts tended to be lower in the group of marathoners, while other leukocyte and lymphocyte subsets were similar to controls. Mitogen-induced lymphocyte proliferation did not differ between groups. Natural killer cell cytotoxic activity (NKCA) was significantly higher in the marathoners versus controls (373 +/- 38 vs 237 +/- 41 total lytic units, respectively, a 57% difference, P = 0.02). For all subjects combined (N = 40) and within the group of marathon runners (N = 22), percent body fat was negatively correlated with NKCA (r = -0.48, P = 0.002; r = -0.49, P = 0.019, respectively), and age was negatively correlated with Con A-induced lymphocyte proliferation (r = -0.41, P = 0.009; r = -0.53, P = 0.011, respectively). These data indicate that NKCA but not mitogen-induced lymphocyte proliferation is higher in marathon runners relative to sedentary controls.

Carbohydrate affects natural killer cell redistribution but not activity after running.

This randomized, double-blind, placebo-controlled study was designed to determine the influence of carbohydrate supplementation on the natural killer cell response to 2.5 h of high-intensity running (76.7 +/- 0.4% VO2max). Thirty experienced marathon runners (VO2max 53.4 +/- 1.0 mL x kg[-1] x min[-1], age 41.5 +/- 1.4 yr) were randomized into carbohydrate supplement (N = 17) and placebo (N = 13) groups. Subjects rested for 10-15 min before a blood sample at 0715, and then ingested 0.75 L of carbohydrate beverage (Gatorade) or placebo. At 0730, subjects began running at 75-80% VO2max for 2.5 h and drank 0.25 L of carbohydrate or placebo fluid every 15 min. Immediately after the 2.5 h run (1000), another blood sample was taken, followed by 1.5 h, 3 h, and 6-h recovery samples. Carbohydrate supplementation versus placebo had a significant effect on the pattern of change in glucose, cortisol, and the blood concentration of natural killer cells ([F (4,25) = 3.79, P = 0.015], but not natural killer cell activity following 2.5 h of intensive running.

Influence of carbohydrate on cytokine and phagocytic responses to 2 h of rowing.

PURPOSE: This study examined the influence of carbohydrate (C) versus placebo (P) beverage ingestion on the phagocytic and cytokine responses to normal rowing training by 15 elite female rowers. METHODS: Athletes received C or P before, during and after, two, 2-h bouts of rowing performed on consecutive days. Blood was collected before and 5-10 min and 1.5 h after rowing. Metabolic measures indicated that training was performed at moderate intensities, with some high-intensity intervals interspersed throughout the sessions. RESULTS: Concentrations of blood neutrophils and monocytes, phagocytic activity, and plasma IL-1ra were significantly lower postexercise after C versus P ingestion. No differences were observed for oxidative burst activity, IL-6, IL-8, or TNFalpha. Glucose was significantly higher after 2 h of rowing with C ingestion; however, cortisol, growth hormone, epinephrine, norepinephrine, and CRP were not affected by carbohydrate. CONCLUSIONS: These data indicate that carbohydrate compared with placebo ingestion attenuated the moderate rise in blood neutrophils, monocytes, phagocytosis, and plasma IL-1ra concentrations that followed 2-h bouts of training in elite female rowers. No changes in blood hormone concentrations were found.

Maturation of lymphocyte immunophenotypes and memory T helper cell differentiation during development in mice.

The goal of this study was to systematically investigate the ontogeny of lymphoid populations throughout postnatal development. In CD-1 mice, peak lymphocyte numbers occurred in blood on postnatal day 10 (d10) including those for natural killers (NK1.1), B cells (CD19), T helper (CD3CD4), naïve T helper (CD4CD62LposCD44low), memory T helper (CD4CD62LnegCD44high), and T cytotoxic (CD3CD8) cells. As percent of total lymphocytes, peaks were achieved by d10 for all T helper subtypes but not B cells which declined to a nadir. In spleen, lymphocyte numbers increased exponentially after d10. Proportionately, NK and T cells peaked on d10, declined by d20, and increased 2-3-fold by d45. Naive T cells constituted the majority of lymphocytes during development while memory cells gained to 2.2% (blood) and 12% (spleen) by d20. C57BL/6 mice had similar profiles except that the B cell nadir and T cell subset peaks were at d5. Peripheralization of critical numbers of lymphocytes by d10, and importantly, development of a repertoire of memory cells by d20, may define immune response capabilities that close the period of immaturity for the neonate.

Influence of photoperiod on immune cell functions in the male Siberian hamster.

The present study tested the hypothesis that immune cell function is influenced by ambient photoperiod. The male Siberian hamster served as the experimental model because day length regulates a variety of seasonal adaptations in physiology. Adult hamsters were in long days (16 h of light daily), which sustains gonadal function, or transferred to short days (8 h) for >4 wk to induce testes regression. Blood was drawn from the ocular sinus or splenocytes obtained to assess basal indexes of immune cell function. In hamsters in short days, natural killer cell cytolytic capacity, as well as spontaneous blastogenesis in both whole blood and isolated lymphocytes, were enhanced compared with that in hamsters in long days. By contrast, phagocytosis and oxidative burst activity by both granulocytes and monocytes were suppressed in hamsters by exposure to short days versus long days. Selective changes in immune cell function coincided with short-day-induced gonadal atrophy. These findings raise the hypothesis that photoperiod regulation of physiological adaptations, including distinct immune cell functions, may help individuals anticipate seasonal challenges posed by opportunistic diseases or climate to facilitate survival.

Influence of skinfold sum and peak VO(2) on immune function in children.

OBJECTIVE: To measure the relationship of skinfold sum and peak VO(2) power with immune function in children. DESIGN: Cross-sectional, with all children tested twice during a 2 month period for peak VO(2), sum of two skinfolds, and immune function, with data from the two measures averaged and then correlated (alpha level, < or = 0.01). Immune measures included leukocyte and lymphocyte subset counts, delayed-typed hypersensitivity (DTH), global IgG antibody response over 4 weeks to pneumococcal vaccination (pIgG), salivary IgA concentration (sIgA), PHA-stimulated lymphocyte proliferation (PHA-SLP), natural killer cell activity (NKCA), and granulocyte and monocyte phagocytosis and oxidative burst activity. SUBJECTS: Seventy-three children (n=42 males, n=31 females) ranging in age from 7 to 13 y (mean+/-s.d. age, 9.9+/-1.7 y). The mean skinfold sum was 28.9+/-17.1 mm, and peak VO(2) 45.8+/-8.1 ml/kg/min. RESULTS: Peak VO(2), skinfold sum, and immune measures did not differ significantly by age or gender. Therefore, correlations were made on combined indices for all subjects. Peak VO(2) and the skinfold sum were not significantly correlated with NKCA, oxidative burst activity, plgG or DTH. Peak VO(2) was negatively correlated with monocyte phagocytosis (r=-0.30, P=0.012) and positively correlated with PHA-SLP (6.25 microg/ml; r=0.35, P=0.004). The skinfold sum was positively correlated with the total leukocyte count (r=0.39, P<0.001), granulocyte count (r=0.36, P=0.002), monocyte count (r=0.38, P=0.001), monocyte phagocytosis (r=0.41, P<0.001), granulocyte phagocytosis (r=0.35, P=0.003), and sIgA (r=0.32, P=0.006), and negatively correlated with PHA-SLP (6.25 microg/ml; r=-0.39, P=0.001). CONCLUSIONS: Data from this study indicate that a high skinfold sum is related to elevated leukocyte subset counts and monocyte/granulocyte phagocytosis, and low PHA-SLP in children.

Reproductive, neuroendocrine, and immune consequences of acute exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin in the Siberian hamster.

The present study tested the hypothesis that acute treatment with 2, 3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) impairs fertility, disrupts the nocturnal melatonin rhythm, and suppresses lymphocyte function. Adult Siberian hamsters administered 2 or 100 microg TCDD/kg body weight/0.2 ml sesame oil had a delayed latency to first litter and an increased adult mortality compared to hamsters given 0.1 microg/kg or vehicle. Within 75 days of TCDD treatment, full reproductive capabilities were achieved. Moreover, the nocturnal melatonin rhythm was not disrupted in adults administered TCDD or in their progeny. Lymphocyte activity varied with respect to time of day and treatment. Lymphocyte proliferation was enhanced at night irrespective of TCDD treatment; during the day, 2 wk after the 2-microg/kg treatment, blastogenesis was reduced compared to that in the 0.1-microg/kg group or in vehicle-treated controls. In contrast, TCDD did not affect the mixed lymphocyte reaction in response to allogeneic antigen when assessed at 2 and 20 wk post-treatment. Thus, findings indicate that TCDD produced acute effects on fertility, mortality, and systemic lymphocyte proliferation, but long-lasting effects on specific aspects of reproductive, neuroendocrine, and immune cell functions were not observed.

Role of photoperiod and the pineal gland in T cell-dependent humoral immune reactivity in the Siberian hamster.

The present study tested the hypothesis that antibody production in response to xenoantigen is modulated by daylength and dependent upon the pineal gland. Alter injection of sheep erythrocytes (SRBC), serum immunoglobulin (Ig) concentrations were 5-fold lower in hamsters in short versus long days. Pinealectomy (Pinx) abolished the nocturnal melatonin rhythm, blocked short-day-mediated testis regression, and eliminated the short-day reduction in Ig production after SRBC treatment. Antibody titers in response to SRBC were equivalently augmented in short-day Pinx and long-day sham hamsters. The results indicate that photoperiodic effects on T cell-dependent humoral immunity are dependent upon the pineal gland. These findings raise the possibility that day length-associated changes in some immune system functions are mediated by the pineal melatonin rhythm.

Sequence comparison of baboon ABO histo-blood group alleles: lesions found in O alleles differ between human and baboon.

Histo-blood group O has only rarely been observed in baboon. Recent discovery of such an animal has provided use the opportunity to investigate the molecular genetics of the ABO locus in baboons. The major baboon prototype O allele, observed in two homozygous and several heterozygous animals, is related to the A allele as is the case in humans. Additional apparent prototype O alleles have been observed in heterozygotes, one of which is related to the B allele. The nucleotide changes conferring the O phenotype in the two known human O alleles have not been observed in any baboon allele. This information will aid the identification of baboons useful for the development of xenotransplantation in humans.

Saliva immunoglobulins in elite women rowers.

Saliva immunoglobulins (sIgA, sIgG, and sIgM) and upper respiratory tract infection (URTI) rates were evaluated in 20 elite female rowers and 19 nonathletes. Also, the influence of carbohydrate versus placebo beverage consumption on saliva immunoglobulin responses to rowing training sessions was measured in 15 rowers and in 5 non-exercising rowers. Saliva samples were collected 1 day before, and 5-10 min and 1.5 h after rowing or rest. Pre-exercise sIgA (but not sIgG or sIgM) concentration was 77% higher in the rowers compared to nonathletes (P < 0.001). Health records kept over 2 months revealed mean 5.2 (SEM 1.2) and 3.3 (SEM 1.1) days with URTI symptoms for the rowers and controls, respectively. For all 39 subjects, and for the 20 rowers separately, no significant correlation was found between URTI symptoms or insulin, cortisol, and growth hormone concentrations and pre-exercise or exercise-related changes in saliva immunoglobulin concentrations or secretion rates. The patterns of change in saliva immunoglobulin concentration and secretion rate did not differ between the carbohydrate and placebo rowing trials, or between exercised and rested athletes. These data indicated an increased sIgA concentration in the female elite rowers compared to the nonathletes, no association between saliva immunoglobulins and URTI, and no effect of a normal 2-hour training session or carbohydrate ingestion on saliva immunoglobulin concentrations or secretion rates.

Change in salivary IgA following a competitive marathon race.

The influence of carbohydrate (1 l/h of a 6 % carbohydrate beverage), gender, and age on salivary IgA (sIgA) changes and incidence of upper respiratory tract infection (URTI) was studied in 98 runners following two competitive marathon races. The pattern of change in sIgA concentration differed significantly between carbohydrate (C) (N = 48) and placebo (P) (N = 50) groups, with higher post-race values measured in P. However, when this was adjusted for saliva protein concentration and saliva secretion rate, no difference between groups was measured. For all subjects combined, sIgA concentration, saliva IgA: protein ratio (spIgA), and sIgA secretion rates fell significantly (21 %, 31 %, and 25 %, respectively) below pre-race levels by 1,5-h post-race (p < 0.001). The pattern of change in all saliva measures did not differ significantly between the 12 women and 86 men in this study, and between the 23 older (> or =50 yr) and 75 younger (< 50 yr) subjects. Ninety-three subjects returned health/sickness logs, and of these, 16 (17 %) reported developing URTI during the 15-d period following the race event. The 1.5-h post-race spIgA concentration, but not sIgA concentration or secretion rate, was lower in runners reporting URTI compared to those who did not (254 +/- 30 and 388 +/- 26 microg*g(-1), respectively, p = 0.002), and this was negatively correlated with the post-race plasma cortisol concentration (r = -0.36, p < 0.001). Of the 16 runners, six were in the C group and 10 in the P group (Chi square = 1.11, p = 0.293). In conclusion, the output of sIgA decreased in runners following a competitive marathon, and this was not influenced by carbohydrate ingestion, age, or gender.