Commentary of the SKLM to the EFSA opinion on risk assessment of N-nitrosamines in food.

Dietary exposure to N-nitrosamines has recently been assessed by the European Food Safety Authority (EFSA) to result in margins of exposure that are conceived to indicate concern with respect to human health risk. However, evidence from more than half a century of international research shows that N-nitroso compounds (NOC) can also be formed endogenously. In this commentary of the Senate Commission on Food Safety (SKLM) of the German Research Foundation (DFG), the complex metabolic and physiological biokinetics network of nitrate, nitrite and reactive nitrogen species is discussed with emphasis on its influence on endogenous NOC formation. Pioneering approaches to monitor endogenous NOC have been based on steady-state levels of N-nitrosodimethylamine (NDMA) in human blood and on DNA adduct levels in blood cells. Further NOC have not been considered yet to a comparable extent, although their generation from endogenous or exogenous precursors is to be expected. The evidence available to date indicates that endogenous NDMA exposure could exceed dietary exposure by about 2-3 orders of magnitude. These findings require consolidation by refined toxicokinetics and DNA adduct monitoring data to achieve a credible and comprehensive human health risk assessment.

Influence of short-term chronic oral cannabidiol application on muscle recovery and performance after an intensive training protocol - a randomized double-blind crossover study.

BACKGROUND: Rapid regeneration after intense exercise is essential for competitive athletes. Based on this assumption, supplementation strategies, focusing on food supplements, are increasing to improve the recovery processes. One such supplement is cannabidiol (CBD) which is gaining more attention in competitive sports. However, the evidence is still lacking and there are no data available about the effect of a short-term chronic application. METHODS: A three-arm double-blind cross-over study was conducted to determine the effects of two different CBD products on performance, muscle damage and inflammatory processes in well-trained athletes. In total 17 subjects took successfully part in this study. Each subject underwent the six-day, high-intensity training protocol three times. After each training session, each subject took either a placebo or a CBD product (60 mg of oil or solubilisate). Between the intervention phases, at least four weeks of washout period was conducted. Before and after the training protocols the performance capacity in countermovement jump (CMJ), back squat (BS), bench press (BP) and 1-mile run were measured and biomarkers for muscle damage (creatine kinase, myoglobin), inflammatory processes (interleukin 6 and 10) and immune cell activity (ratios of neutrophil granulocytes, lymphocytes and, platelets) were analyzed. For statistical analyses, the current version of R and a linear mixed model was used. RESULTS: It could identify different effects of the training protocol depending on performance level (advanced or highly advanced athletes) (p < .05). Regardless of the performance level, muscle damage and a reduction in performance could be induced by the training protocol. Only CBD oil was associated with a reduction in myoglobin concentration (p < .05) in advanced athletes. Concerning immune activity, a significant decrease in platelets lymphocyte ratios was observed in advanced athletes after placebo treatment (p < .05). CBD oil application showed a slight inhibitory effect (p < .10). Moreover, the reduction in performance differs between the performance levels. A significant decrease in CMJ was observed in advanced athletes and a decreasing trend in BS was observed in highly advanced athletes after placebo treatment (p < 0.10). Both CBD products do not affect performance parameters. For inflammatory parameters, no effects were observed. CONCLUSION: It was found that the performance level of the subjects was a decisive factor and that they responded differently to the training protocol and the CBD application. However, no clear effects of either CBD product were found and further research is needed to identify the long-term effects of CBD application.

Differences in Consumption Behaviour of Dietary Supplements in Competitive Athletes Depends on Sports Discipline.

BACKGROUND: The consumption of dietary supplements (DS) is widespread among the general population and competitive athletes. However, only a few competitive athletes seek information from experts about the effects and use of DS. Furthermore, it is currently unknown whether certain sports have a higher affinity for DS than others. METHODS: This study aimed to identify differences between different sports categories and subgroups that may have a very high affinity for DS. For this purpose, competitive athletes were surveyed. The survey included the type of sport, the training frequency, the number of competitions, the consumption behaviour of five DS categories (general health, regeneration promotion, performance enhancement, booster, and weight loss) as well as personal data such as biological sex and age. Subsequently, correlations, configural frequencies (CFA), and multiple correspondence analyses (MCA) were used to identify subgroups with a high affinity of consumption behaviour. RESULTS: A total of 409 questionnaires could be evaluated. It was found that all DS categories except weight loss were related. In addition, it was observed that in sports from the power category and from the endurance category, there was even higher consumption behaviour than in other sports categories. Male power athletes in particular have a higher affinity for consuming DS than other subgroups. CONCLUSIONS: This study shows that there is a clear different consumption behaviour depending on the type of sport. Male power athletes in particular are the subgroup with the greatest consumption behaviour and therefore require special education on the effects and use of DS. This subgroup in particular should receive increased attention in counselling on DS to minimise the possible risks of DS use.

Quinoa as phytopharmaceutical? Urinary elimination of ecdysterone after consumption of quinoa alone and in combination with spinach.

The phytosteroid ecdysterone is classified as an anabolic agent and has been included on the monitoring list of the World Anti-Doping Agency since 2020. Therefore, the consumption of food rich in ecdysterone, such as quinoa and spinach, is the focus of a lively debate. Thus, the urinary excretion of ecdysterone and its metabolites in humans was investigated following quinoa consumption alone and in combination with spinach. Eight participants (four male and four female) were included, and they ingested 368 ± 61 g cooked quinoa alone and in combination with 809 ± 115 g spinach after a washout. Post-administration urines were analyzed by LC-MS/MS. After intake of both preparations, ecdysterone and two metabolites were excreted in the urine. The maximum concentration of ecdysterone ranged from 0.44 to 5.5 µg/mL after quinoa and from 0.34 to 4.1 µg/mL after quinoa with spinach. The total urinary excreted amount as parent drug plus metabolites was 2.61 ± 1.1% following quinoa intake and 1.7 ± 0.9% in combination with spinach. Significant differences were found in the total urinary excreted amount of ecdysterone, 14-deoxy-ecdysterone, and 14-deoxy-poststerone. Only small portions of ecdysterone from quinoa and the combination with spinach were excreted in the urine, suggesting that both quinoa and spinach are poor sources of ecdysterone in terms of bioavailability.

Resistance training alters body composition in middle-aged women depending on menopause - A 20-week control trial.

BACKGROUND: Resistance training (RT) is effective in counteracting the age- and menopause-related loss of muscle mass (MM) and strength in middle-aged women (40-60 years). Research on RT with free weights is limited in pre- and post-menopausal women. Based on this, a 20-week training intervention was conducted with this population to investigate the effects of systematic RT with free weights on strength capacity and body composition. METHOD: Forty-one healthy women (52.0 ± 3.6 years) participated in this study. After 10-week control phase (no RT, T0-T1) followed by a 10-week intervention phase (T1-T2) with RT twice a week and 6-8 sets of each muscle per week. Subjects were randomly assigned to a low-intensity (50% 1-RM) or moderate-intensity (75% 1-RM) RT group and divided into pre-menopausal and post-menopausal according to their hormone profile. Fat-free mass (FFM), MM, fat mass (FM), muscle thickness (Vastus lateralis (VL), Rectus femoris (RF), Triceps brachii (TB)), grip strength, 1-RM squat and bench press were assessed before and after each phase. Statistical analysis was performed using a linear mixed model to account for fixed (time and group) and random (individual) effects. RESULTS: A total of 31 women successfully completed the study. No injuries occurred during the intervention. Significant increases in 1-RM squat and bench press were observed in all groups. No interaction effect was observed for the strength parameters. In pre-menopausal women, FFM, MM and RF muscle thickness increased significantly, while VL showed a trend. These effects were not present in post-menopausal women regardless of RT intensity. CONCLUSION: RT with free weight is safe and effective for middle-aged women to increase 1-RM. Hypertrophy effects were found exclusively in pre-menopausal women. To achieve hypertrophy and/or body composition changes in post-menopausal women, larger training volumes (> 6-8 sets/muscle per week) are likely required.

Acetaldehyde as a Food Flavoring Substance: Aspects of Risk Assessment.

The Senate Commission on Food Safety (SKLM) of the German Research Foundation (DFG) has reviewed the currently available data in order to assess the health risks associated with the use of acetaldehyde as a flavoring substance in foods. Acetaldehyde is genotoxic in vitro. Following oral intake of ethanol or inhalation exposure to acetaldehyde, systemic genotoxic effects of acetaldehyde in vivo cannot be ruled out (induction of DNA adducts and micronuclei). At present, the key question of whether acetaldehyde is genotoxic and mutagenic in vivo after oral exposure cannot be answered conclusively. There is also insufficient data on human exposure. Consequently, it is currently not possible to reliably assess the health risk associated with the use of acetaldehyde as a flavoring substance. However, considering the genotoxic potential of acetaldehyde as well as numerous data gaps that need to be filled to allow a comprehensive risk assessment, the SKLM considers that the use of acetaldehyde as a flavoring may pose a safety concern. For reasons of precautionary consumer protection, the SKLM recommends that the scientific base for approval of the intentional addition of acetaldehyde to foods as a flavoring substance should be reassessed.

Basic concepts of mixture toxicity and relevance for risk evaluation and regulation.

Exposure to multiple substances is a challenge for risk evaluation. Currently, there is an ongoing debate if generic "mixture assessment/allocation factors" (MAF) should be introduced to increase public health protection. Here, we explore concepts of mixture toxicity and the potential influence of mixture regulation concepts for human health protection. Based on this analysis, we provide recommendations for research and risk assessment. One of the concepts of mixture toxicity is additivity. Substances may act additively by affecting the same molecular mechanism within a common target cell, for example, dioxin-like substances. In a second concept, an "enhancer substance" may act by increasing the target site concentration and aggravating the adverse effect of a "driver substance". For both concepts, adequate risk management of individual substances can reliably prevent adverse effects to humans. Furthermore, we discuss the hypothesis that the large number of substances to which humans are exposed at very low and individually safe doses may interact to cause adverse effects. This commentary identifies knowledge gaps, such as the lack of a comprehensive overview of substances regulated under different silos, including food, environmentally and occupationally relevant substances, the absence of reliable human exposure data and the missing accessibility of ratios of current human exposure to threshold values, which are considered safe for individual substances. Moreover, a comprehensive overview of the molecular mechanisms and most susceptible target cells is required. We conclude that, currently, there is no scientific evidence supporting the need for a generic MAF. Rather, we recommend taking more specific measures, which focus on compounds with relatively small ratios between human exposure and doses, at which adverse effects can be expected.

Acute Effects of Single Versus Combined Inhaled ß2-Agonists Salbutamol and Formoterol on Time Trial Performance, Lung Function, Metabolic and Endocrine Variables.

BACKGROUND: High prevalence rates of ß2-agonist use among athletes in competitive sports makes it tempting to speculate that illegitimate use of ß2-agonists boosts performance. However, data regarding the potential performance-enhancing effects of inhaled ß2-agonists and its underlying molecular basis are scarce. METHODS: In total, 24 competitive endurance athletes (12f/12m) participated in a clinical double-blinded balanced four-way block cross-over trial to investigate single versus combined effects of ß2-agonists salbutamol (SAL) and formoterol (FOR), to evaluate the potential performance enhancement of SAL (1200 µg, Cyclocaps, Pb Pharma GmbH), FOR (36 µg, Sandoz, HEXAL AG) and SAL + FOR (1200 µg + 36 µg) compared to placebo (PLA, Gelatine capsules containing lactose monohydrate, Pharmacy of the University Hospital Ulm). Measurements included skeletal muscle gene and protein expression, endocrine regulation, urinary/serum ß2-agonist concentrations, cardiac markers, cardiopulmonary and lung function testing and the 10-min time trial (TT) performance on a bicycle ergometer as outcome variables. Blood and urine samples were collected pre-, post-, 3 h post- and 24 h post-TT. RESULTS: Mean power output during TT was not different between study arms. Treatment effects regarding lung function (p < 0.001), echocardiographic (left ventricular end-systolic volume p = 0.037; endocardial global longitudinal strain p < 0.001) and metabolic variables (e.g. NR4A2 and ATF3 pathway) were observed without any influence on performance. In female athletes, total serum ß2-agonist concentrations for SAL and FOR were higher. Microarray muscle gene analysis showed a treatment effect for target genes in energy metabolism with strongest effect by SAL + FOR (NR4A2; p = 0.001). Of endocrine variables, follicle-stimulating hormone (3 h Post-Post-TT), luteinizing hormone (3 h Post-Pre-TT) and insulin (Post-Pre-TT) concentrations showed a treatment effect (all p < 0.05). CONCLUSIONS: No endurance performance-enhancing effect for SAL, FOR or SAL + FOR within the permitted dosages compared to PLA was found despite an acute effect on lung and cardiac function as well as endocrine and metabolic variables in healthy participants. The impact of combined ß2-agonists on performance and sex-specific thresholds on the molecular and cardiac level and their potential long-term performance enhancing or health effects have still to be determined. TRIAL REGISTRATION: Registered at Eudra CT with the number: 2015-005598-19 (09.12.2015) and DRKS with number DRKS00010574 (16.11.2021, retrospectively registered).

Urinary Excretion of Ecdysterone and Its Metabolites Following Spinach Consumption.

SCOPE: The phytosteroid ecdysterone is present in spinach. In this study, the urinary elimination of ecdysterone and its metabolites in humans is investigated following spinach consumption of two different culinary preparations. METHODS AND RESULTS: Eight participants (four males, four females) ingested 950 (27.1) g sautéed spinach (average [±standard deviation (SD)]) and 912 (70.6) g spinach smoothie as second intervention after washout. Post-administration urines are analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). After intake of both preparations, ecdysterone and two metabolites, 14-deoxy-ecdysterone, and 14-deoxy-poststerone, are excreted in urine. The maximum concentration of ecdysterone is ranging from 0.09 to 0.41 µg mL-1 after sautéed spinach and 0.08-0.74 µg mL-1 after smoothie ingestion. The total excreted amount (mean% [±SD]) in the urine as a parent drug plus the metabolites is only 1.4 (1.0) for both sautéed spinach and smoothie. The apparent sex related differences in 14-deoxy-poststerone excretion will need further investigations. CONCLUSION: Only a small proportion of ecdysterone from spinach is excreted into urine. No significant differences are found in concentration and recovered amount (%) of ecdysterone, 14-deoxy-ecdysterone, and 14-deoxy-poststerone in urine between sautéed spinach and smoothie ingestion. A discrimination between ecdysterone from food or preparations will be challenging based on urinary concentrations only, at least for later post-administration samples.

The Anabolic Effect of Fenugreek: A Systematic Review with Meta-analysis.

The use of plant steroids to improve physical health and performance is becoming increasingly popular. One of these plant steroids is diosgenin, which is mainly available in fenugreek. As a result, some studies have been conducted to improve physical health. Fenugreek extracts are also becoming increasingly popular in the context of athletic performance. Based on these assumptions, a systematic review with meta-analysis was conducted to evaluate the promoting effects of fenugreek on strength performance, body composition, and hormone concentration. Four databases were screened according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The current version of ReviewManager (RevMan) was used for the statistical evaluation. Seven studies with 449 participants (378 male, 71 female) met the inclusion criteria. A small effect of fenugreek was detected for total testosterone (standard mean difference (SMD): 0.32; 95% confidence interval (CI): 0.09 0.55), free testosterone (SMD: 0.24; 95% CI: -0.04, 0.52), lean body mass (SMD: 0.19; 95% CI: -0.10, 0.49), fat mass (SMD: -0.19; 95% CI: -0.44, 0.05), and leg press performance (SMD: 0.22; 95% CI: -0.02, 0.47), in male athletes. The meta-analysis shows that chronic application of fenugreek has performance-enhancing and anabolic effects in male athletes, but no statements can be made for female athletes.

Combinatory Effects of Training and Nutritive Administration of Carbohydrates and Protein via Food on Strength in Postmenopausal Women, and Old Men and Women.

The age-related loss of muscle mass promotes many impairments. Training and protein supplementation are suggested to prevent muscle wasting, but recommendations for all populations are not based on scientific evidence. This study combines protein/carbohydrate supplementation (PCS) and training for seniors and postmenopausal women. Project A: 51 postmenopausal women (PMW, 57.3 ± 3.0 years old) underwent health-oriented training (12 weeks, moderate-strength training + moderate-endurance training). The intervention group (IG) additionally received 110 g sour milk cheese (SMC) and toast. Project B: 25 women and 6 men (65.9 ± 4.9 years old) performed intense sling training (12 weeks). The IG additionally received 110 g SMC, toast, and buttermilk. Strength was tested before and after in both studies. Project A: there was significant increase in strength, no additional effect of PCS, and a reduction in body fat in the controls. Project B: there was significant increase in strength, significant additional effects of PCS for trunk strength, and a significant reduction in body weight. Combining training and PCS may counteract strength loss. Combined endurance/resistance training is recommended to PMW for whom the benefits of PCS are restricted. Aged subjects may benefit from PCS when training intensely, but these benefits may be strongly individual.

Evaluation of the genotoxic potential of acrylamide: Arguments for the derivation of a tolerable daily intake (TDI value).

This opinion of the Senate Commission on Food Safety (SKLM) of the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) presents arguments for an updated risk assessment of diet-related exposure to acrylamide (AA), based on a critical review of scientific evidence relevant to low dose exposure. The SKLM arrives at the conclusion that as long as an appropriate exposure limit for AA is not exceeded, genotoxic effects resulting in carcinogenicity are unlikely to occur. Based on the totality of the evidence, the SKLM considers it scientifically justified to derive a tolerable daily intake (TDI) as a health-based guidance value.

Chemical Stability and Bioactivity of tanshinone I, tanshinone IIA, cryptotanshinone and dihydrotanshinone in in vitro test systems.

Danshen Si Wu is a Traditional Chinese Medicine used for menopausal complains. Beside tanshinone IIA (Tan IIA), Danshen also contains tanshinone I (Tan I), cryptotanshinone (CT) and dihydrotanshinone (DT). The aim of this study was to compare the biological activity of these tanshinones and to determine their cytotoxicity and genotoxicity. Purities and stabilities of the substances were analyzed by LC-DAD and LC-MS analyses. DT and CT concentrations decreased rapidly in dimethylsulfoxide and were converted to Tan I and Tan IIA, respectively. In aqueous solution concentration of all tanshinones decreased after 24 h. Tan I and Tan IIA showed dose-dependent bioactivity mediated by ERα and ERß. No cytotoxic and genotoxic effects for Tan I and Tan IIA were detected. In a yeast transactivation assay Tan I and Tan IIA showed antiandrogenic activity. A significant anabolic activity in C2C12 cells could be detected for Tan I and Tan IIA. In conclusion our data provide evidence that Tan I and Tan IIA are the most relevant bioactive tanshinones in Danshen. Our finding that all tanshinones display a certain instability in aqueous solutions is relevant when discussing their potential therapeutic benefits in humans.

The Influence of Levothyroxine on Body Composition and Physical Performance in Subclinical Hypothyroidism.

Levothyroxine is commonly used to treat hypothyroidism. This study investigates how far the intake of L-T4 influences body composition, energy expenditure, respiratory quotient as well as strength, endurance and mobility in premenopausal women who suffer from subclinical hypothyroidism. Twenty-five women (27.36±5.77 years) with subclinical hypothyroidism were included in the study. The intake of levothyroxine was assumed. Subjects were examined immediately after study inclusion, after two months of levothyroxine use, and after TSH was fully adjusted to the reference range. In all measurements TSH, fT3 and fT4 were determined, body weight, body composition, energy expenditure and the respiratory quotient were measured, and a test battery was performed to identify strength, mobility and endurance capacity. TSH decreased from 5.95±0.99 µIU/ml at study inclusion to 1.2±0.33 µIU/ml after final trial. No change in weight, BMI, muscle mass, fat mass, energy expenditure and respiratory quotient was observed (p>0.05). A significant improvement in chest press (p=0.002), leg extension (p<0.001), right-hand grip strength (p=0.009) shoulder mobility (p<0.001), hip mobility (p=0.07), explosive strength (p=0.041) and the anaerobic threshold (p=0.13) was identified. Likewise, a non-significant (p=0.298) increase in left-hand grip strength could be detected.In summary, although levothyroxine does not positively affect body composition, energy expenditure and respiratory quotient, it can improve strength, mobility and endurance performance. For this reason, treatment with levothyroxine is recommended to improve exercise capacity in subclinical hypothyroidism.

Running for Your Life: Metabolic Effects of a 160.9/230 km Non-Stop Ultramarathon Race on Body Composition, Inflammation, Heart Function, and Nutritional Parameters.

Moderate endurance exercise leads to an improvement in cardiovascular performance, stress resilience, and blood function. However, the influence of chronic endurance exercise over several hours or days is still largely unclear. We examined the influence of a non-stop 160.9/230 km ultramarathon on body composition, stress/cardiac response, and nutrition parameters. Blood samples were drawn before (pre) and after the race (post) and analyzed for ghrelin, insulin, irisin, glucagon, cortisol, kynurenine, neopterin, and total antioxidant capacity. Additional measurements included heart function by echocardiography, nutrition questionnaires, and body impedance analyses. Of the 28 included ultra-runners (7f/21m), 16 participants dropped out during the race. The remaining 12 finishers (2f/10m) showed depletion of antioxidative capacities and increased inflammation/stress (neopterin/cortisol), while energy metabolism (insulin/glucagon/ghrelin) remained unchanged despite a high negative energy balance. Free fat mass, protein, and mineral content decreased and echocardiography revealed a lower stroke volume, left end diastolic volume, and ejection fraction post race. Optimizing nutrition (high-density protein-rich diet) during the race may attenuate the observed catabolic and inflammatory effects induced by ultramarathon running. As a rapidly growing discipline, new strategies for health prevention and extensive monitoring are needed to optimize the athletes' performance.

Effects of Carbohydrate and Protein Administration by Food Items on Strength Response after Training in Stable COPD.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is one of the world's most common diseases and reasons for death. Systemic consequences, especially reduced muscle strength, muscle mass and muscle function, are common and contribute to worsening prognosis and increasing morbidity and mortality. There is strong evidence that physical activity and strength training are effective in prolonging life and lead to better quality of life. Numerous studies have shown that ingestion of protein and carbohydrates after strength training can increase regeneration of strength in young athletes. Recently, we demonstrated that the same effect can be achieved with these macronutrients administered in a meal. Until now, it is not clear if patients with COPD, integrated in regular physical training, respond similarly. METHODS: Prescribed strength training, consisting of two sets circular training with machines for big muscle groups was supplemented with a meal rich in protein and carbohydrates. Changes in maximum strength after 24 h were investigated to find out about the impact of this meal on physical capacity. A pilot study was conducted with pragmatic cross-over design. RESULTS: With nutritive intervention, strength in both knee extensor and chest press were significantly higher than in control training. CONCLUSION: The study showed beneficial effects for the intake of protein and carbohydrates in changes in maximum strength. For now, the underlying mechanism remains unclear. Clinical relevance needs further research. The study design and study protocol can be used for further studies with only small adaptions.

Salivary nitrate/nitrite and acetaldehyde in humans: potential combination effects in the upper gastrointestinal tract and possible consequences for the in vivo formation of N-nitroso compounds-a hypothesis.

Subsequent to the dietary uptake of nitrate/nitrite in combination with acetaldehyde/ethanol, combination effects resulting from the sustained endogenous exposure to nitrite and acetaldehyde may be expected. This may imply locoregional effects in the upper gastrointestinal tract as well as systemic effects, such as a potential influence on endogenous formation of N-nitroso compounds (NOC). Salivary concentrations of the individual components nitrate and nitrite and acetaldehyde are known to rise after ingestion, absorption and systemic distribution, thereby reflecting their respective plasma kinetics and parallel secretion through the salivary glands as well as the microbial/enzymatic metabolism in the oral cavity. Salivary excretion may also occur with certain drug molecules and food constituents and their metabolites. Therefore, putative combination effects in the oral cavity and the upper digestive tract may occur, but this has remained largely unexplored up to now. In this Guest Editorial, published evidence on exposure levels and biokinetics of nitrate/nitrite/NOx, NOC and acetaldehyde in the organism is reviewed and knowledge gaps concerning combination effects are identified. Research is suggested to be initiated to study the related unresolved issues.

Genistein interferes with antitumor effects of cisplatin in an ovariectomized breast cancer xenograft tumor model.

Genistein (GEN) has been demonstrated to interfere with antitumor effects of cisplatin (CIS) in vitro. To analyze whether these findings are also relevant in vivo, we examined the effects of combined GEN and CIS treatment in an ovariectomized nude mouse breast cancer xenograft model. Tumor growth and markers for antitumor activity were determined after three weeks of treatment. Furthermore, the concentrations of GEN metabolites were measured in serum, liver, and xenograft tumor tissues using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Three weeks' oral exposure to GEN at a dose of 5 mg kg-1·d-1 resulted in an average concentration of total GEN metabolite equivalent as high as 0.2729 nmol g-1 wet weight in xenograft tumor tissues. At this dosage, GEN significantly antagonized the antitumor effects of CIS. Mechanistically, GEN blocked both the inhibition of cell proliferation and induction of apoptosis triggered by CIS. Moreover, GEN concentrations in xenograft tumor tissues were found to be significantly higher than in serum and liver. In conclusion, our findings suggested that oral GEN exposure at a level comparable to dietary exposure in humans could interfere with CIS chemotherapy.

The ELSA trial: single versus combinatory effects of non-prohibited beta-2 agonists on skeletal muscle metabolism, cardio-pulmonary function and endurance performance-study protocol for a randomized 4-way balanced cross-over trial.

BACKGROUND: Asthma and/or airway hyper-responsiveness (AHR) are common in elite endurance athletes with a high prevalence rate of beta-2 adrenoreceptor (beta-2) agonists use. Nevertheless, there are data on dose-dependent ergogenic effects of beta-2 agonists suggesting increased muscle strength, endurance and neuromuscular performance. Therefore, most beta-2 agonists belong to the World Anti Doping Agency (WADA) list of prohibited substances and it is tempting to speculate that illegitimate use of beta-2 agonists might be a common practice to boost performance in competitive sports. It is currently unknown whether or not inhaled beta-2 agonists enhance performance by stimulatory effects in skeletal and cardiac muscle. METHODS: The ELSA trial is a double-blinded, placebo-controlled, randomized, balanced, four-way cross-over study. Study participants (n=24, 12 ♀, 12 ♂) complete four study arms (i.e. periods with treatment A, placebo; B, salbutamol; C, formoterol; D, formoterol + salbutamol) in random order after an initial preliminary testing session. Participants inhale the study medication 20 min before the 10-min time trial (TT; exercise performance test), where participants cycle 10 min at the highest possible workload. Cardiac output is measured continuously. A skeletal muscle biopsy is collected 3 h after the TT. Study endpoints include measures of skeletal muscle expression of nuclear receptors, hormones and cytokine levels, urinary and plasma concentrations of salbutamol and formoterol, circulating cardiac markers, cardiopulmonary function and exercise performance (average power and peak power during the TT). Blood and urine are collected and respiratory testing is performed 24 h post TT. This clinical trial evaluates the potential performance-enhancing effects of non-prohibited, not medically indicated inhaled short- and long-acting beta-2 agonists on skeletal muscle gene expression, endocrine regulation, cardiac biomarkers, cardiopulmonary function and acute endurance exercise performance. These data will be used by WADA to adapt the annually published list of prohibited substances (WADA 2021) and will be published in scientific journals. TRIAL REGISTRATION: The trial is registered at the European Clinical Trials Database (Eudra CT) with the number: 2015-005598-19 as well as at the German register for clinical studies (DRKS number 00010574 ).

Effects of Cannabidiol Supplementation on Skeletal Muscle Regeneration after Intensive Resistance Training.

Cannabidiol supplements (CBD) are increasingly consumed by athletes to improve regeneration. However, the evidence for the pro-regenerative effects of CBD in sports is quite limited. Therefore, our aim was to investigate the effects of a single CBD supplementation in a six-arm placebo-controlled crossover study after resistance training on performance and muscle damage. Before and after the resistance training, one-repetition maximum in the back squat (1RM BS), countermovement jump (CMJ), and blood serum concentrations of creatine kinase (CK) and myoglobin (Myo) were measured in healthy, well-trained participants. 16 out of 21 participants completed the study and were included in the analysis. In 1RM BS, a significant decrease was observed after 24 h (p < 0.01) but not after 48 and 72 h. A significant group difference was detected after 72 h (p < 0.05; ES = 0.371). In CMJ, no significant changes were observed. The CK and Myo concentrations increased significantly after 24 h (CK: p < 0.001; Myo: p < 0.01), 48 h (CK: p < 0.001; Myo: p < 0.01) and 72 h (CK: p < 0.001; Myo: p < 0.001). After 72 h, significant group differences were observed for both muscle damage biomarkers (CK: p < 0.05 ES = 0.24; Myo: p < 0.05; ES = 0.21). The results show small but significant effects on muscle damage and recovery of squat performance after 72 h. However, more data are required for clearer statements concerning potential pro-regenerative effects of CBD supplementation after resistance training.