Polymorphisms in Genes Encoding VDR, CALCR and Antioxidant Enzymes as Predictors of Bone Tissue Condition in Young, Healthy Men

The aim of the study was to assess significant predictors of bone mineral content (BMC) and bone mineral density (BMD) in a group of young, healthy men at the time of reaching peak bone mass. Regression analyses showed that age, BMI and practicing combat sports and team sports at a competitive level (trained vs. untrained group; TR vs. CON, respectively) were positive predictors of BMD/BMC values at various skeletal sites. In addition, genetic polymorphisms were among the predictors. In the whole population studied, at almost all measured skeletal sites, the SOD2 AG genotype proved to be a negative predictor of BMC, while the VDR FokI GG genotype was a negative predictor of BMD. In contrast, the CALCR AG genotype was a positive predictor of arm BMD. ANOVA analyses showed that, regarding SOD2 polymorphism, the TR group was responsible for the significant intergenotypic differences in BMC that were observed in the whole study population (i.e., lower BMC values of leg, trunk and whole body were observed in AG TR compared to AA TR). On the other hand, higher BMC at L1-L4 was observed in the SOD2 GG genotype of the TR group compared to in the same genotype of the CON group. For the FokI polymorphism, BMD at L1-L4 was higher in AG TR than in AG CON. In turn, the CALCR AA genotype in the TR group had higher arm BMD compared to the same genotype in the CON group. In conclusion, SOD2, VDR FokI and CALCR polymorphisms seem to affect the association of BMC/BMD values with training status. In general, at least within the VDR FokI and CALCR polymorphisms, less favorable genotypes in terms of BMD (i.e., FokI AG and CALCR AA) appear to be associated with a greater BMD response to sports training. This suggests that, in healthy men during the period of bone mass formation, sports training (combat and team sports) may attenuate the negative impact of genetic factors on bone tissue condition, possibly reducing the risk of osteoporosis in later age.

Effects of Rhodiola rosea supplementation on mental performance, physical capacity, and oxidative stress biomarkers in healthy men

PURPOSE

The objective of this study was to investigate the effects of chronic Rhodiola rosea (R. rosea) supplementation on mental and physical performance, as well as hormonal and oxidative stress biomarkers.

METHODS

Twenty-six healthy male students received either R. rosea extract (600 mg/day; RR) or placebo (PL) in a randomized double-blind trial. Prior to supplementation (Term I) and following 4 weeks of supplementation (Term II), the students underwent psychomotor tests for simple and choice reaction time, included in the Vienna Test System. Also, the subjects performed VO_2peak test. Blood samples were obtained before and after the test to measure the hormonal profile (cortisol, testosterone, and growth hormone), as well as the biomarkers of oxidative stress (lipid hydroperoxides, total antioxidant capacity, and superoxide dismutase) and muscle damage (creatine kinase).

RESULTS

R. rosea ingestion shortened reaction time and total response time. Moreover, a greater relative increase in the number of correct responses was observed in RR group as compared to the PL group. No changes in endurance exercise capacity and hormonal profile were observed after R. rosea ingestion. R. rosea ingestion raised plasma total antioxidant capacity. It did not, however, affect other measured parameters.

CONCLUSION

Chronic R. rosea ingestion does not affect physical performance, but can improve the results of some psychomotor tests (simple and choice reaction time) in young, healthy, and physically active men. The improvements in mental performance, however, at least in our study, seem not to be related to changes in cortisol release or antioxidant activity of R. rosea extract. Thus, the specific mechanisms responsible for these effects still need to be elucidated.

Endurance training selectively increases high-density lipoprotein-bound sphingosine-1-phosphate in the plasma

Sphingosine-1-phosphate (S1P) is a bioactive lysosphingolipid that is found in relatively high concentration in human plasma. Erythrocytes, endothelial cells, and activated platelets are the main sources of circulating S1P. The majority of plasma S1P is transported bound to high-density lipoprotein (HDL) and albumin. In recent years, HDL-bound S1P attracted much attention due to its cardioprotective and anti-atherogenic properties. We have previously found that endurance-trained athletes are characterized by higher plasma S1P concentration compared to untrained individuals. This finding prompted us to examine the effect of endurance training on S1P metabolism in blood. Thirteen healthy, untrained, male subjects completed an 8-week training program on a rowing ergometer. Three days before the first, and 3 days after the last training session, blood samples were drawn from an antecubital vein. We found that total plasma S1P concentration was increased after the training. Further analysis of different plasma fractions showed that the training selectively elevated HDL-bound S1P. This effect was associated with activation of sphingosine kinase in erythrocytes and platelets and enhanced S1P release from red blood cells. We postulate that increase in HDL-bound S1P level is one of the mechanisms underlying beneficial effects of regular physical activity on cardiovascular diseases.

Exercise increases sphingoid base-1-phosphate levels in human blood and skeletal muscle in a time- and intensity-dependent manner

Purpose

Sphingosine-1-phosphate (S1P) regulates cardiovascular function and plays an important role in muscle biology. We have previously reported that cycling exercise increased plasma S1P. Here, we investigated the effect of exercise duration and intensity on plasma and skeletal muscle S1P levels.

Methods

In the first experiment, 13 male athletes performed a 60-min exercise at 65 % of VO_2max and a graded exercise until exhaustion on a rowing ergometer. Samples of the venous blood were taken, and plasma, erythrocytes and platelets were isolated. In the second experiment, ten male moderately active subjects performed three consecutive periods of one-leg knee extension exercise (at 25, 55 and 85 % of the maximal workload). Muscle biopsies and blood samples from the radial artery and femoral veins were taken.

Results

Under basal conditions, S1P was released from the leg, as its concentration was lower in the arterial than in the venous plasma (p < 0.01). Exercise until exhaustion increased plasma S1P and sphinganine-1-phosphate (SA1P) concentration (p < 0.05), whereas moderate-intensity exercise elevated only SA1P (p < 0.001). Although knee extension increased muscle S1P content (p < 0.05), it was not released but taken up across the leg during exercise. However, sphingosine was released from both working and resting leg at the highest workload (p < 0.05).

Conclusions

Plasma S1P concentration is elevated only by high-intensity exercise which results, at least in part, from increased availability of sphingosine released by skeletal muscle. In addition, exercise markedly affects S1P dynamics across the leg. We speculate that S1P may play an important role in adaptation of skeletal muscle to exercise.

Electronic supplementary material

The online version of this article (doi:10.1007/s00421-014-3080-x) contains supplementary material, which is available to authorized users.

Change in blood gelsolin concentration in response to physical exercise

Plasma gelsolin (pGSN) produced by muscle is an abundant protein of extracellular fluids capable of severing actin filaments and eliminating actin from the circulation. Additionally, pGSN modulates the cellular effects of some bioactive lipids. In this study we test the hypothesis that hormonal and metabolic adaptations to exercise are associated with changes in gelsolin concentration in blood. Plasma samples were collected from twenty healthy males recruited from untrained (UT, n=10) and endurance trained (ET, n=10) groups that performed 30-60 minutes of exercise on a cycloergometer at a workload corresponding to 70% of VO2max. Gelsolin concentration was determined by quantitative Western blot analysis with an anti-human gelsolin antibody. The gelsolin concentration in UT and ET subjects before starting exercise ranged from 104 to 330 and 163 to 337 µg · ml(-1) respectively. After 30 minutes of exercise we observed a significant decrease of plasma gelsolin in the UT group (p<0.05) while the gelsolin concentration in the ET group rose on average from 244 to 271 µg · ml(-1). However, this increase did not reach statistical significance. Endurance training might increase the ability of muscle tissue to express plasma gelsolin as part of an adaptive mechanism.

Intakes of selected nutrients, bone mineralisation and density of adolescent female swimmers over a three-year period

The aim of this study was to conduct three-year monitoring of bone mineralization (BMC) and bone mineral density (BMD) of adolescent girls engaged in swimming at the time of attaining the peak bone mass and of their counterparts leading a rather sedentary life, considering the intakes of calcium, phosphorus and protein, as well as the proportions among those nutrients. Two groups of girls aged 11-13 years were studied 3 times at yearly intervals: untrained controls (n = 20) and those engaged in competitive swimming (n = 20). Bone density was determined by dual-energy X-ray absorptiometry (DXA) in the lumbar spine (L2 - L4). Nutrient intakes (energy, protein, calcium, phosphorus) were assessed from 24-h recalls. The group of swimmers had significantly lower BMI values than the control group. No systematic, significant between-group differences were found in nutrient intake or in bone mineralization variables. Calcium intake was below the recommended norm in all subjects but mean values of bone mineralization variables (BMC, BMD) steadily increased in both groups. The BMD z-scores proved negative throughout the three-year period of early adolescence in both groups of girls and that decrease was significant in swimmers. This could have been due to insufficient calcium intake as well as to inadequate calcium-to-phosphate and protein-to-calcium ratios and, when continued, might result in a decreased bone mass in adulthood.

Exercise increases plasma levels of sphingoid base-1 phosphates in humans

AIM

In recent years, blood sphingolipids attracted much attention and have been implicated in both pathophysiology and prevention of cardiovascular diseases and insulin resistance. However, factors affecting concentration and metabolism of sphingolipids in blood remain poorly recognized. We have previously found that exercise alters skeletal muscle sphingolipid metabolism. This finding prompted us to examine whether physical activity induces similar effects in blood.

METHODS

Twenty healthy male patients were assigned to either untrained (UT, n = 10) or endurance trained (ET, n = 10) group. The patients performed either a 30 (UT group) or 60 (ET group) min exercise on a cycloergometer at a workload corresponding to 70% of VO(2max) . Blood samples were taken just before exercise, after 30 and 60 (ET group only) min of pedalling and following a 30-min rest.

RESULTS

ET patients were characterized by higher basal plasma sphingosine-1-phosphate (S1P) concentration and decreased content of sphingosine, S1P, sphinganine-1-phosphate (SA1P) and ceramide in erythrocytes. In ET group, plasma concentrations of all measured sphingolipids remained stable both during and after exercise. On the other hand, in UT patients, the post-exercise levels of S1P and SA1P were markedly higher compared with the baseline values and this effect was accompanied by decreased erythrocyte ceramide content.

CONCLUSION

It is likely that single bout of exercise and endurance training enhances production and release of S1P by erythrocytes. We speculate that exercise-induced increase in plasma S1P concentration might be one of the mechanisms underlying beneficial effects of physical activity on cardiovascular health and insulin sensitivity.