Luiz-Claudio Cameron

High Intensity Ultraendurance Promotes Early Release Of Muscle Injury Markers

Objective: To evaluate the impact of high-intensity ultraendurance (HIU) cycling, using it as a possible way to understand muscle injury kinetics and blood immune cells’ release during high-intensity prolonged exercise Design: Male amateur triathletes enrolled during a cycling race of the International Bike Championship 800 km cycling relay (∼23 h). Each athlete alternately cycled 20–25 minutes until exhaustion and performed a total of approximately 200 km. Results: Creatine kinase levels in blood reached a 300% rise in a sigmoidal pattern, while lactate dehydrogenase levels increased by 30–40% following a hyperbolic pattern. Aspartate aminotransferase and alanine aminotransferase levels increased by up to 250% and 140%, respectively. Liver injury markers such as alkaline phosphatase and γ-glutamyltransferase remained stable. Platelets increased by 20–30% from pre-exercise, and there was no change in haematocrit during the race. White blood cells rose by nearly 200%. Leucocytes rose 210% during the race, with a major component coming from neutrophils, which increased more than 300%. Triacylglycerol levels were decreased at the finish and total cholesterol levels remained unchanged. Urate increased (by up to 35%) during the first half of the race, and urea levels increased with a different pattern, increasing by 45% in the second half. Conclusions: This study showed the blood appearance kinetics of muscle injury markers and some metabolites. It is suggested that the increase in these enzymes came primarily from muscle damage, rather than liver damage, and that white blood cells are selectively mobilised independently of haemoconcentration. The early appearance of muscle injury markers in this kind of exercise was also shown.

Glutamine protects against increases in blood ammonia in football players in an exercise intensity-dependent way

Objective: High-intensity and prolonged exercise significantly enhances the levels of plasma ammonia, a metabolite with toxic effects on the central nervous system. The main purpose of the present study was to evaluate the metabolic response of athletes to glutamine (Gln) and alanine (Ala) supplementation, since these amino acids have a significant influence on both anaplerosis and gluconeogenesis. Methods: Professional football players were assigned to groups receiving either Gln or Ala supplementation (100 mg kg−1 body weight); this supplementation was either short-term or long-term and was given immediately before exercise. The players were evaluated using two exercise protocols, one with intervals (n = 18) and the other with continuous intensity (n = 12). Results: Both types of exercises increased ammonia, urate, urea and creatinine in blood. Chronic Gln supplementation partially protected against hyperammonemia after a football match (intermittent exercise: Gln −140 (SEM 13)% vs Ala −240 (SEM 37)%) and after continuous exercise at 80% of the maximum heart rate (Gln −481 (SEM 44)% vs placebo −778 (SEM 99)%). Urate increased by 10−20% in all groups, independently of supplementation. Glutamine once a day supplementation induced a greater elevation in urate as compared to alanine at the end of the game; however, long-term supplementation provoked a lesser increment in urate. Exercise induced similar increases in creatinine as compared to their respective controls in either acute or chronic glutamine administration. Conclusions: Taken together, the results suggest that chronically supplemented Gln protects against exercise-induced hyperammonemia depending on exercise intensity and supplementation duration.

Effect of caffeine supplementation on haematological and biochemical variables in elite soccer players under physical stress conditions

Objective: To evaluate the effect of caffeine on white cell distribution and muscle injury markers in professional soccer players during exercise. Methods: 22 male athletes completed a placebo controlled double blind test protocol to simulate a soccer match, followed by a Yo-Yo intermittent recovery test. Results: Exercise caused an increase in packed cell volume that was enhanced by caffeine. Caffeine and exercise had a synergistic effect on the blood lymphocyte count, which increased by about 38% after exercise, and by an additional 35% when combined with caffeine. Caffeine promoted an exercise independent rise in circulating monocytes, and a synergistic action of exercise and caffeine was observed on segmented neutrophils. Caffeine promoted thrombocytosis. Plasma adenosine deaminase, aspartate aminotransferase, and lactate dehydrogenase concentrations were enhanced by exercise, and alanine transaminase concentration was enhanced in both groups, with a synergistic effect of caffeine. Conclusions: The pronounced increase in the white cell count in the group receiving caffeine appeared to be caused by greater muscle stress and consequently more intense endothelial and muscle cell injury. The use of caffeine may augment the risk of muscle damage in athletes.

A sportomics strategy to analyze the ability of arginine to modulate both ammonia and lymphocyte levels in blood after high-intensity exercise

BackgroundExercise is an excellent tool to study the interactions between metabolic stress and the immune system. Specifically, high-intensity exercises both produce transient hyperammonemia and influence the distribution of white blood cells. Carbohydrates and glutamine and arginine supplementation were previously shown to effectively modulate ammonia levels during exercise. In this study, we used a short-duration, high-intensity exercise together with a low carbohydrate diet to induce a hyperammonemia state and better understand how arginine influences both ammonemia and the distribution of leukocytes in the blood.MethodsBrazilian Jiu-Jitsu practitioners (men, n = 39) volunteered for this study. The subjects followed a low-carbohydrate diet for four days before the trials and received either arginine supplementation (100 mg·kg-1 of body mass·day-1) or a placebo. The intergroup statistical significance was calculated by a one-way analysis of variance, followed by Student’s t-test. The data correlations were calculated using Pearson’s test.ResultsIn the control group, ammonemia increased during matches at almost twice the rate of the arginine group (25 mmol·L-1·min-1 and 13 μmol·L-1·min-1, respectively). Exercise induced an increase in leukocytes of approximately 75%. An even greater difference was observed in the lymphocyte count, which increased 2.2-fold in the control group; this increase was partially prevented by arginine supplementation. The shape of the ammonemia curve suggests that arginine helps prevent increases in ammonia levels.ConclusionsThese data indicate that increases in lymphocytes and ammonia are simultaneously reduced by arginine supplementation. We propose that increased serum lymphocytes could be related to changes in ammonemia and ammonia metabolism.

Caffeine Decreases Systemic Urea in Elite Soccer Players during Intermittent Exercise.

PURPOSE We investigated the effects of caffeine on the ammonia and amino acid metabolism of elite soccer players. METHODS In this double-blind randomized study, athletes (n = 19) received 5 mg·kg caffeine or lactose (LEx, control) and performed 45 min of intermittent exercise followed by an intermittent recovery test (Yo-Yo IR2) until exhaustion. The caffeine-supplemented athletes were divided into two groups (CEx and SCEx) depending on their serum caffeine levels (<900% and >10,000%, respectively). Data were analyzed by ANOVA and Tukey post hoc test (P < 0.05 was considered to be statistically significant). RESULTS Caffeine supplementation did not significantly affect the performance (LEx = 12.3 ± 0.3 km·h, 1449 ± 378 m; CEx = 12.2 ± 0.5 km·h, 1540 ± 630 m; SCEx = 12.3 ± 0.5 km·h, 1367 ± 330 m). Exercise changed the blood concentrations of several amino acids and increased the serum concentrations of ammonia, glucose, lactate, and insulin. The LEx group showed an exercise-induced increase in valine (∼29%), which was inhibited by caffeine. Higher serum caffeine levels abolished the exercise-induced increase (∼24%-27%) in glutamine but did not affect the exercise-induced increase in alanine (∼110%-160%) and glutamate (42%-61%). In response to exercise, the SCEx subjects did not exhibit an increase in uremia and showed a significantly lower increase in their serum arginine (15%), citrulline (16%), and ornithine (ND) concentrations. CONCLUSIONS Our data suggest that caffeine might decrease systemic urea by decreasing the glutamine serum concentration, which decreases the transportation of ammonia to the liver and thus urea synthesis.

Effect of thyroid hormone T3 on Myosin-Va expression in the central nervous system

Thyroid hormones (THs) are essential for brain development, where they regulate gliogenesis, myelination, cell proliferation and protein synthesis. Hypothyroidism severely affects neuronal growth and establishment of synaptic connections. Triiodothyronine (T3), the biologically active form of TH, has a central function in these activities. So, Myosin-Va (Myo-Va), a molecular motor protein involved in vesicle and RNA transport, is a good candidate as a target for T3 regulation. Here, we analyzed Myo-Va expression in euthyroid and hypothyroid adult rat brains and synaptosomes. We observed a reduction of Myo-Va expression in cultured neural cells from newborn hypothyroid rat brain, while immunocytochemical experiments showed a punctate distribution of this protein in the cytoplasm of cells. Particularly, Myo-Va co-localized with microtubules in neurites, especially in their varicosities. Myo-Va immunostaining was stronger in astrocytes and neurons of controls when compared with hypothyroid brains. In addition, supplementation of astrocyte cultures with T3 led to increased expression of Myo-Va in cells from both euthyroid and hypothyroid animals, suggesting that T3 modulates Myo-Va expression in neural cells both in vivo and in vitro. We have further analyzed Myo-Va expression in U373 cells, a human glioblastoma line, and found the same punctate cytoplasmic protein localization. As in normal neural cells, this expression was also increased by T3, suggesting that the modulatory mechanism exerted by T3 over Myo-Va remains active on astrocyte tumor cells. These data, coupled with the observation that Myo-Va is severely affected in hypothyroidism, support the hypothesis that T3 activity regulates neural motor protein expression, taking Myo-Va as a model. As a consequence, reduced T3 activity could supposedly affect axonal transport and synaptic function, and could therefore explain disturbances seen in the hypothyroid brain.

IQGAP1 Interactome Analysis by In Vitro Reconstitution and Live Cell 3-Color FRET Microscopy

IQGAP1 stimulates branched actin filament nucleation by activating N‐WASP, which then activates the Arp2/3 complex. N‐WASP can be activated by other factors, including GTP‐bound Cdc42 or Rac1, which also bind IQGAP1. Here we report the use of purified proteins for in vitro binding and actin polymerization assays, and Förster (or fluorescence) resonance energy transfer (FRET) microscopy of cultured cells to illuminate functional interactions among IQGAP1, N‐WASP, actin, and either Cdc42 or Rac1. In pyrene‐actin assembly assays containing N‐WASP and Arp2/3 complex, IQGAP1 plus either small G protein cooperatively stimulated actin filament nucleation by reducing the lag time before 50% maximum actin polymerization was reached. Similarly, Cdc42 and Rac1 modulated the binding of IQGAP1 to N‐WASP in a dose‐dependent manner, with Cdc42 enhancing the interaction and Rac1 reducing the interaction. These in vitro reconstitution results suggested that IQGAP1 interacts by similar, yet distinct mechanisms with Cdc42 versus Rac1 to regulate actin filament assembly through N‐WASP in vivo. The physiological relevance of these multi‐protein interactions was substantiated by 3‐color FRET microscopy of live MDCK cells expressing various combinations of fluorescent N‐WASP, IQGAP1, Cdc42, Rac1, and actin. This study also establishes 3‐color FRET microscopy as a powerful tool for studying dynamic intermolecular interactions in live cells.

Investigating the Cellular and Metabolic Responses of World-Class Canoeists Training: A Sportomics Approach

(1) Background: We have been using the Sportomics approach to evaluate biochemical and hematological changes in response to exercise. The aim of this study was to evaluate the metabolic and hematologic responses of world-class canoeists during a training session; (2) Methods: Blood samples were taken at different points and analyzed for their hematological properties, activities of selected enzymes, hormones, and metabolites; (3) Results: Muscle stress biomarkers were elevated in response to exercise which correlated with modifications in the profile of white blood cells, where a leukocyte rise was observed after the canoe session. These results were accompanied by an increase in other exercise intensity parameters such as lactatemia and ammonemia. Adrenocorticotropic hormone and cortisol increased during the exercise sessions. The acute rise in both erythrocytes and white blood profile were probably due to muscle cell damage, rather than hepatocyte integrity impairment; (4) Conclusion: The cellular and metabolic responses found here, together with effective nutrition support, are crucial to understanding the effects of exercise in order to assist in the creation of new training and recovery planning. Also we show that Sportomics is a primal tool for training management and performance improvement, as well as to the understanding of metabolic response to exercise.