Theodore Parthimos

Evidence for the participation of the stimulated sympathetic nervous system in the regulation of carnitine blood levels of soccer players during a game

Catecholamines and carnitine blood levels are closely implicated with training. The aim of the study was to investigate the effect of sympathetic nervous system stimulation on carnitine and its fraction levels during training. Blood was obtained from 14 soccer players pregame, at intermission, and postgame. Catecholamines were measured with high-performance liquid chromatography methods; muscle enzymes creatine kinase and lactate dehydrogenase as well as lactate, pyruvate, and total antioxidant status with commercial kits; and carnitine and fraction levels with tandem mass spectrometry. Total antioxidant status (2.97 +/- 0.13 vs 0.96 +/- 0.10 mmol/L, P < .01) as well as free carnitine levels (20.47 +/- 4.0 vs 12.30 +/- 2.8 micromol/L, P < .001) were remarkably decreased especially postgame. Total acylcarnitines (5.20 +/- 1.8 vs 9.42 +/- 3.0 micromol/L, P < .001) and especially total very long-chain acylcarnitines (0.80 +/- 0.01 vs 1.85 +/- 0.03 micromol/L, P < .001) as well as catecholamine levels (adrenaline: 230 +/- 31 vs 890 +/- 110 pmol/L, P < .01; noradrenaline: 1.53 +/- 0.41 vs 3.7 +/- 0.6 nmol/L, P < .01) were significantly increased in players postgame. A statistically significant inverse correlation was found between adrenaline and free carnitine (r = -0.51, P < .01); and a positive correlation was found between adrenaline, total acylcarnitines (r = 0.58, P < .01), and total long-chain acylcarnitine (r = 0.49, P < .01). The significant positive correlation of adrenaline levels with total acylcarnitine and total long-chain acylcarnitine blood levels in athletes as well as the inverse correlation with free carnitine levels may indicate participation of the stimulated sympathetic nervous system in the regulation of some carnitine fraction levels during exercise.

alpha-tocopherol supplementation reduces the elevated 8-hydroxy-2-deoxyguanosine blood levels induced by training in basketball players.

Abstract Background: The aim of the present study was to investigate the effect of α-tocopherol (α-Te) supplementation on DNA oxidative damage induced by heavy training in basketball players. Methods: Blood was obtained from 10 players before (group A) and after training (group B) and after 1month on α-Te (200mg/day, orally) supplementation, before (group C) and after training (group D). Total antioxidant status (TAS), muscle enzyme activities and the biomarker of DNA oxidation, 8-hydroxy-2-deoxyguanosine (8-OHdG), were measured using commercial kits. α-Te and catecholamine blood levels were determined using HPLC methods. Results: TAS was higher in the groups with α-Te (groups C and D). Levels of 8-OHdG and muscle creatine kinase (CK) and lactate dehydrogenase (LDH) were remarkably lower (0.20±0.03ng/mL, 120±15 U/L and 430±90U/L, respectively) in the group with α-Te (group D) than in group B (0.42±0.05ng/mL, 286±12U/L and 688±88U/L, respectively; p<0.001). 8-OHdG levels were negatively correlated to TAS and positively to CK levels. Conclusions: α-Te supplementation may reduce DNA oxidation induced by training by protecting muscle cell “death” from glutamate entry and/or by elevation of TAS via amelioration of lipid peroxidation. Clin Chem Lab Med 2006;44:1004–8.

Erythrocyte membrane Na+,K+-ATPase and Mg2+-ATPase activities in subjects with methylenetetrahydrofolate reductase (MTHFR) 677 C→T genotype and moderate hyperhomocysteinaemia. The role of L-phenylalanine and L-alanine

Abstract Background: Increased homocysteine (Hcy) blood levels are correlated with vascular and neurological problems. The aim of our study was to investigate erythrocyte membrane Na+,K+-ATPase and Mg2+-ATPase activities in patients with methylenetetrahydrofolate reductase (MTHFR) 677 C→T genotype. Methods: Blood was obtained from 25 patients before and after folic acid supplementation and from controls (n=30) once. Plasma folate, vitamin B12 and total antioxidant status (TAS) were measured using commercial kits, Hcy was determined by HPLC and membrane enzyme activities were measured spectrophotometrically. Results: Mg2+-ATPase remained unaltered. Membrane Na+,K+-ATPase activity was remarkably increased in patients (0.77±0.06μmolPi/h × mg protein) and decreased to normal levels (0.52±0.05μmolPi/h × mg protein; p<0.001) after therapy. TAS did not differ significantly before and after treatment. Hcy levels were significantly higher before therapy (25.4±2.8μmol/L) than levels after therapy (12.1±2.0μmol/L; p<0.001) and in controls (10.5±2.5μmol/L, p<0.001). In vitro, L-phenylalanine (Phe) reversed to normal the stimulated enzyme from patients before therapy. In addition, Phe incubation of the Hcy activated membrane Na+,K+-ATPase from controls resulted in restoration of its activity, whereas L-alanine (Ala) incubation protected the enzyme from Hcy activation. Conclusions: The increased membrane Na+,K+-ATPase activity may be due to high -SH group Hcy levels. In vitro, Phe reversed the increase in enzyme activity induced by Hcy in controls, as well as the stimulated membrane enzyme in untreated patients. Ala protected the enzyme from Hcy action.

L-Cysteine supplementation prevents exercise-induced alterations in human erythrocyte membrane acetylcholinesterase and Na+,K+-ATPase activities

Abstract Background: L-Cysteine (L-Cys) is implicated in the reduction of free radical production. The aim of this study was to investigate whether L-Cys supplementation prevents modulation of the activities of erythrocyte membrane acetylcholinesterase (AChE), Na+,K+-ATPase and Mg2+-ATPase induced by free radicals in basketball players during training. Methods: Blood was obtained from 10 basketball male players before (group A) and after a game (group B) and after 1 week of L-Cys (0.5 g/24 h orally) supplementation before (group C) and after training (group D). Lactate, pyruvate and total antioxidant status (TAS) were measured using commercial kits and the enzyme activities were determined spectrophotometrically. Results: Both lactate and pyruvate levels remarkably increased after exercise. In contrast, TAS levels significantly decreased in group B, increased in group C and then declined (group D), reaching those of group A. AChE activity was statistically increased post-exercise (3.98±0.04 × mg protein) compared with pre-training (2.90±0.05 × mg protein, p<0.01). Na+,K+-ATPase activity was also higher post-exercise (1.27±0.05 μmol Pi/h×mg protein) than that pre-exercise (0.58±0.04 μmol Pi/h×mg protein, p<0.001). When the players were supplemented with L-Cys, both AChE and Na+,K+-ATPase activities remained unaltered post-exercise. Mg2+-ATPase activities were unchanged in all groups studied. Conclusions: L-Cys supplementation may protect the enzyme activities studied against stimulation induced by free radical production during training in athletes by ameliorating their total antioxidant capacity. Clin Chem Lab Med 2007;45:67–72.

The in vivo and in vitro effects of L-carnitine supplementation on the erythrocyte membrane acetylcholinesterase, Na+, K+-ATPase and Mg2+-ATPase activities in basketball players.

Abstract Background: We investigated whether the activities of erythrocyte membrane acetylcholinesterase (AChE), Na+, K+-ATPase and Mg2+-ATPase are modulated in basketball players pre- vs. post-forced training with or without L-carnitine (L-C) supplementation. Methods: Blood was obtained from 10 male players pre-game (group A) and post-game (group B) and after 1 month L-C supplementation (2 g/24 h orally) pre-training (group C) and post-training (group D). Lactate, pyruvate and total antioxidant status (TAS) were measured with commercial kits, catecholamines with HPLC and the enzyme activities spectrophotometrically. Results: Lactate, pyruvate, AChE, Na+, K+-ATPase and catecholamines were increased (p<0.001) and TAS was decreased (p<0.001) in group B. In contrast, TAS remained unaltered and the all enzyme activities were reduced (p<0.001) in group D at the same time of study. Mg2+-ATPase activity remained unchanged. In vitro incubation of the modulated AChE and Na+, K+-ATPase with L-C (25 μM) from group B and group D resulted in a non-significant reduction of the enzymes in group B and complete restoration of their activities in group D. Conclusions: The increase of AChE and Na+, K+-ATPase activities may be due to the elevation of catecholamines in group B. Carnitine utilization by the muscles during training may result in a reduction of the enzyme activities (group D). The latter is supported by the recovery of the enzyme activities after incubation of the membranes from group D with L-C. Clin Chem Lab Med 2008;46:137–42.

Significant reduction of erythrocyte glucose-6-phosphate dehydrogenase activity in soccer-players during play. Evidence for catecholamine mediated enzyme inhibition.

We previously reported that mild reductions in erythrocyte glucose-6-phosphate dehydrogenase (G6PD) activity normally induced by training of basketball players was prevented by the administration of the antioxidants L-cysteine or a-tocopherol (1, 2). Because high catecholamine concentrations are reported to contribute to total antioxidant status (TAS) (3), and since G6PD activity is closely related to oxidative stress, we investigated enzyme activity in soccer players at the intermission and post-game in relation to their TAS and blood catecholamine concentrations. This study was approved by the Greek Ethical Committee as amended in 1989. Fourteen, 20-year-old soccer players who were actively participating in the Greek Soccer Championship volunteered to participate. They had trained for at least two years, consisting of two to three 60-min sessions per week, for nine months each year. A championship game took place on a 60 m=40 m pitch. Each team was comprised of seven players; two forwards, two mildfielders, two defenders and one goalkeeper. To ensure similar technical ability between each team, opponents were chosen with a similar league position to the ‘‘experimental’’ team. Clinical and biochemical blood parameters were assessed pre-game (3–4 min prior to start), at the beginning of half-time and at the end of the game (within 3–4 min post-game). Capillary blood samples were obtained from the left thumb for ana-