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Can 3 mg·kg-1 of Caffeine Be Used as An Effective Nutritional Supplement to Enhance the Effects of Resistance Training in Rugby Union Players?
Tamilio, RA, Clarke, ND, Duncan, MJ, Morris, R, Grgic, J, Tallis, J
Nutrients. 2021;(10)
Abstract
The present study uniquely examined the effect of 3 mg·kg-1 chronic caffeine consumption on training adaptations induced by 7-weeks resistance training and assessed the potential for habituation to caffeine's ergogenicity. Thirty non-specifically resistance-trained university standard male rugby union players (age (years): 20 ± 2; height (cm): 181 ± 7; body mass (kg): 92 ± 17) completed the study), who were moderate habitual caffeine consumers (118 ± 110 mg), completed the study. Using a within-subject double-blind, placebo-controlled experimental design, the acute effects of caffeine intake on upper and lower limb maximal voluntary concentric and eccentric torque were measured using isokinetic dynamometry (IKD) prior to and immediately following a resistance training intervention. Participants were split into strength-matched groups and completed a resistance-training program for seven weeks, consuming either caffeine or a placebo before each session. Irrespective of group, acute caffeine consumption improved peak eccentric torque of the elbow extensors (p < 0.013), peak concentric torque of the elbow flexors (p < 0.005), total eccentric work of the elbow flexors (p < 0.003), total concentric work of the knee extensors (p < 0.001), and total concentric and eccentric work of the knee flexors (p < 0.046) following repeated maximal voluntary contractions. Many of these acute caffeine effects were still prevalent following chronic exposure to caffeine throughout the intervention. The training intervention resulted in significant improvements in upper and lower body one-repetition maximum strength (p < 0.001). For the most part, the effect of the training intervention was equivalent in both the caffeine and placebo groups, despite a small but significant increase (p < 0.037) in the total work performed in the participants that consumed caffeine across the course of the intervention. These results infer that caffeine may be beneficial to evoke acute improvements in muscular strength, with acute effects prevalent following chronic exposure to the experimental dose. However, individuals that consumed caffeine during the intervention did not elicit superior post-intervention training- induced adaptations in muscular strength.
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Association of Weight-Adjusted Caffeine and β-Blocker Use With Ophthalmology Fellow Performance During Simulated Vitreoretinal Microsurgery.
Roizenblatt, M, Dias Gomes Barrios Marin, V, Grupenmacher, AT, Muralha, F, Faber, J, Jiramongkolchai, K, Gehlbach, PL, Farah, ME, Belfort, R, Maia, M
JAMA ophthalmology. 2020;(8):819-825
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Abstract
IMPORTANCE Vitreoretinal surgery can be technically challenging and is limited by physiologic characteristics of the surgeon. Factors that improve accuracy and precision of the vitreoretinal surgeon are invaluable to surgical performance. OBJECTIVES To establish weight-adjusted cutoffs for caffeine and β-blocker (propranolol) intake and to determine their interactions in association with the performance of novice vitreoretinal microsurgeons. DESIGN, SETTINGS, AND PARTICIPANTS This single-blind cross-sectional study of 15 vitreoretinal surgeons who had less than 2 years of surgical experience was conducted from September 19, 2018, to September 25, 2019, at a dry-laboratory setting. Five simulations were performed daily for 2 days. On day 1, performance was assessed after sequential exposure to placebo, low-dose caffeine (2.5 mg/kg), high-dose caffeine (5.0 mg/kg), and high-dose propranolol (0.6 mg/kg). On day 2, performance was assessed after sequential exposure to placebo, low-dose propranolol (0.2 mg/kg), high-dose propranolol (0.6 mg/kg), and high-dose caffeine (5.0 mg/kg). INTERVENTIONS Surgical simulation tasks were repeated 30 minutes after masked ingestion of placebo, caffeine, or propranolol pills during the 2 days. MAIN OUTCOMES AND MEASURES An Eyesi surgical simulator was used to assess surgical performance, which included surgical score (range, 0 [worst] to 700 [best]), task completion time, intraocular trajectory, and tremor rate (range, 0 [worst] to 100 [best]). The nonparametric Friedman test followed by Dunn-Bonferroni post hoc test was applied for multiple comparisons. RESULTS Of 15 vitreoretinal surgeons, 9 (60%) were male, with a mean (SD) age of 29.6 (1.4) years and mean (SD) body mass index (calculated as weight in kilograms divided by height in meters squared) of 23.15 (2.9). Compared with low-dose propranolol, low-dose caffeine was associated with a worse total surgical score (557.0 vs 617.0; difference, -53.0; 95% CI, -99.3 to -6.7; P = .009), a lower antitremor maneuver score (55.0 vs 75.0; difference, -12.0; 95% CI, -21.2 to -2.8; P = .009), longer intraocular trajectory (2298.6 vs 2080.7 mm; difference, 179.3 mm; 95% CI, 1.2-357.3 mm; P = .048), and increased task completion time (14.9 minutes vs 12.7 minutes; difference, 2.3 minutes; 95% CI, 0.8-3.8 minutes; P = .048). Postcaffeine treatment with propranolol was associated with performance improvement; however, surgical performance remained inferior compared with low-dose propranolol alone for total surgical score (570.0 vs 617.0; difference, -51.0; 95% CI, -77.6 to -24.4; P = .01), tremor-specific score (50.0 vs 75.0; difference, -16.0; 95% CI, -31.8 to -0.2; P = .03), and intraocular trajectory (2265.9 mm vs 2080.7 mm; difference, 166.8 mm; 95% CI, 64.1-269.6 mm; P = .03). CONCLUSIONS AND RELEVANCE The findings suggest that performance of novice vitreoretinal surgeons was worse after receiving low-dose caffeine alone but improved after receiving low-dose propranolol alone. Their performance after receiving propranolol alone was better than after the combination of propranolol and caffeine. These results may be helpful for novice vitreoretinal surgeons to improve microsurgical performance.
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ADOR2A C Allele Carriers Exhibit Ergogenic Responses to Caffeine Supplementation.
Grgic, J, Pickering, C, Bishop, DJ, Del Coso, J, Schoenfeld, BJ, Tinsley, GM, Pedisic, Z
Nutrients. 2020;(3)
Abstract
Caffeine's ergogenic effects on exercise performance are generally explained by its ability to bind to adenosine receptors. ADORA2A is the gene that encodes A2A subtypes of adenosine receptors. It has been suggested that ADORA2A gene polymorphisms may be responsible for the inter-individual variations in the effects of caffeine on exercise performance. In the only study that explored the influence of variation in ADORA2A-in this case, a common polymorphism (rs5751876)-on the ergogenic effects of caffeine on exercise performance, C allele carriers were identified as "non-responders" to caffeine. To explore if C allele carriers are true "non-responders" to the ergogenic effects of caffeine, in this randomized, double-blind study, we examined the acute effects of caffeine ingestion among a sample consisting exclusively of ADORA2A C allele carriers. Twenty resistance-trained men identified as ADORA2A C allele carriers (CC/CT genotype) were tested on two occasions, following the ingestion of caffeine (3 mg/kg) and a placebo. Exercise performance was evaluated with movement velocity, power output, and muscle endurance during the bench press exercise, countermovement jump height, and power output during a Wingate test. Out of the 25 analyzed variables, caffeine was ergogenic in 21 (effect size range: 0.14 to 0.96). In conclusion, ADORA2A (rs5751876) C allele carriers exhibited ergogenic responses to caffeine ingestion, with the magnitude of improvements similar to what was previously reported in the literature among samples that were not genotype-specific. Therefore, individuals with the CT/CC genotype may still consider supplementing with caffeine for acute improvements in performance.
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Caffeine improves text reading and global perception.
Franceschini, S, Lulli, M, Bertoni, S, Gori, S, Angrilli, A, Mancarella, M, Puccio, G, Facoetti, A
Journal of psychopharmacology (Oxford, England). 2020;(3):315-325
Abstract
BACKGROUND Reading is a unique human skill. Several brain networks involved in this complex skill mainly involve the left hemisphere language areas. Nevertheless, nonlinguistic networks found in the right hemisphere also seem to be involved in sentence and text reading. These areas do not deal with phonological information, but are involved in verbal and nonverbal pattern information processing. The right hemisphere is responsible for global processing of a scene, which is needed for developing reading skills. AIMS Caffeine seems to affect global pattern processing specifically. Consequently, our aim was to discover if it could enhance text reading skill. METHODS In two mechanistic studies (n=24 and n=53), we tested several reading skills, global and local perception, alerting, spatial attention and executive functions, as well as rapid automatised naming and phonological memory, using a double-blind, within-subjects, repeated-measures design in typical young adult readers. RESULTS A single dose of 200 mg caffeine improved global processing, without any effect on local information processing, alerting, spatial attention and executive or phonological functions. This improvement in global processing was accompanied by faster text reading speed of meaningful sentences, whereas single word/pseudoword or pseudoword text reading abilities were not affected. These effects of caffeine on reading ability were enhanced by mild sleep deprivation. CONCLUSIONS These findings show that a small quantity of caffeine could improve global processing and text reading skills in adults.
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Stored RBC metabolism as a function of caffeine levels.
D'Alessandro, A, Fu, X, Reisz, JA, Kanias, T, Page, GP, Stone, M, Kleinman, S, Zimring, JC, Busch, M, ,
Transfusion. 2020;(6):1197-1211
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Abstract
BACKGROUND Coffee consumption is extremely common in the United States. Coffee is rich with caffeine, a psychoactive, purinergic antagonist of adenosine receptors, which regulate red blood cell energy and redox metabolism. Since red blood cell (purine) metabolism is a critical component to the red cell storage lesion, here we set out to investigate whether caffeine levels correlated with alterations of energy and redox metabolism in stored red blood cells. STUDY DESIGN AND METHODS We measured the levels of caffeine and its main metabolites in 599 samples from the REDS-III RBC-Omics (Recipient Epidemiology Donor Evaluation Study III Red Blood Cell-Omics) study via ultra-high-pressure-liquid chromatography coupled to high-resolution mass spectrometry and correlated them to global metabolomic and lipidomic analyses of RBCs stored for 10, 23, and 42 days. RESULTS Caffeine levels positively correlated with increased levels of the main red cell antioxidant, glutathione, and its metabolic intermediates in glutathione-dependent detoxification pathways of oxidized lipids and sugar aldehydes. Caffeine levels were positively correlated with transamination products and substrates, tryptophan, and indole metabolites. Expectedly, since caffeine and its metabolites belong to the family of xanthine purines, all xanthine metabolites were significantly increased in the subjects with the highest levels of caffeine. However, high-energy phosphate compounds ATP and DPG were not affected by caffeine levels, despite decreases in glucose oxidation products-both via glycolysis and the pentose phosphate pathway. CONCLUSION Though preliminary, this study is suggestive of a beneficial correlation between the caffeine levels and improved antioxidant capacity of stored red cells.
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Lack of Effect of 12-Week Treatment with Risankizumab on the Pharmacokinetics of Cytochrome P450 Probe Substrates in Patients with Moderate to Severe Chronic Plaque Psoriasis.
Khatri, A, Cheng, L, Camez, A, Ignatenko, S, Pang, Y, Othman, AA
Clinical pharmacokinetics. 2019;(6):805-814
Abstract
OBJECTIVE The objective of this study was to characterize the effects of risankizumab on the in vivo activity of cytochrome P450 (CYP) 1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A in psoriasis patients using a cocktail approach. METHODS Patients with moderate to severe chronic plaque psoriasis (n = 21) received single oral doses of sensitive probe substrates for CYP1A2 (caffeine 100 mg), CYP2C9 (warfarin 10 mg), CYP2C19 (omeprazole 20 mg), CYP2D6 (metoprolol 50 mg), and CYP3A (midazolam 2 mg) on day 1, followed by 12 weeks of subcutaneous risankizumab treatment of 150 mg once every 4 weeks from day 8 to day 92, and again the same cocktail of substrates on day 98. Serial blood samples were collected for determination of the CYP probe drugs and metabolites with and without risankizumab. Trough samples were collected for risankizumab. RESULTS The 90% confidence intervals (CIs) for the area under the plasma concentration-time curve (AUC) from time zero to infinity (AUC∞) ratios for the CYP probe substrates administered with risankizumab versus without risankizumab were within the default 0.8-1.25 equivalence bounds. Similar results were observed for maximum plasma concentration (Cmax), except for omeprazole, for which the lower bound of the 90% CI for Cmax (0.73) extended slightly below the default equivalence limit. No differences were observed in metabolite-to-parent drug Cmax or AUC ratios with risankizumab versus without risankizumab. Risankizumab trough plasma concentrations significantly exceeded those of the phase III regimen of risankizumab in psoriasis (150 mg subcutaneously at weeks 0 and 4 and every 12 weeks thereafter). CONCLUSIONS Risankizumab did not affect the in vivo activity of CYP1A2, CYP2C9, CYP2C19, CYP2D6, or CYP3A enzymes in patients with moderate or severe plaque psoriasis and therefore has no potential for drug interactions through these enzymes. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT02772601.
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Melatonin and Caffeine Supplementation Used, Respectively, as Protective and Stimulating Agents in the Cryopreservation of Human Sperm Improves Survival, Viability, and Motility after Thawing compared to Traditional TEST-Yolk Buffer.
Pariz, JR, Ranéa, C, Monteiro, RAC, Evenson, DP, Drevet, JR, Hallak, J
Oxidative medicine and cellular longevity. 2019;:6472945
Abstract
Cryopreservation processes can damage spermatozoa and impair structural and functional cell characteristics. Plasma, nuclear membranes, and cellular organelles can suffer from the freeze and thaw process. This study evaluates the protective and stimulant effect of melatonin and caffeine supplementation on the functional characteristics of human spermatozoa before and after freezing. Thirty seminal samples from normozoospermic men aged 19-45 years old collected between October 2012 and May 2017 were included. Semen samples were supplemented with either 2 mM melatonin (MEL) prior to cryopreservation, 2 mM caffeine (CAF) in postthaw, or CAF and MEL (CM) in precryopreservation and postthaw, respectively. Kinetics and seminal parameters, mitochondrial activity, DNA fragmentation, and reactive oxygen species (ROS) levels were analyzed before and after cryopreservation. A significant reduction in sperm concentration, total and progressive motility, sperm kinetics, and mitochondrial activity, as well as a significant increase in DNA fragmentation and ROS production in postthaw samples compared to fresh samples, was identified. After administration of a caffeine and/or melatonin supplement, there was a significant increase in progressive motility in the CAF (p = 0.005) and CM (p = 0.048) groups, as well as mitochondrial activity in the CM group (p < 0.05). Cryopreservation has negative effects on overall sperm quality and increases ROS production. A combination of caffeine and melatonin in prefreeze and postthaw sperm samples has proven to be a very effective and simple way to improve semen quality. This will be particularly useful for initial low-quality semen samples, those which suffer the most from the freezing/thawing process.
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Phenotyping of CYP 4501A2 Activity by Total Overnight Salivary Caffeine Assessment (TOSCA) in Patients on Warfarin Treatment: A Cross-Sectional Study.
Tarantino, G, Capone, D, Contaldi, P, Gianno, A, Teresa, M, Tufano, A
Clinical and applied thrombosis/hemostasis : official journal of the International Academy of Clinical and Applied Thrombosis/Hemostasis. 2018;(6):928-935
Abstract
Warfarin is an oral anticoagulant, commonly used for primary and secondary prevention of venous and arterial thromboembolic events. The drug is characterized by narrow therapeutic index, widespread individual variability in clinical response, and high rates of adverse events, particularly bleeding complications. For these reasons, a close monitoring of the dosage, using the frequent assessment of coagulation status by means of International Normalized Ratio value, is mandatory. Warfarin is metabolized by hepatic cytochrome P-450. High CYP 450 activity may lead to low drug concentration and requires high warfarin doses to reach efficacy; conversely, low CYP 450 activity is responsible for high drug concentration and needs for low doses to avoid potential toxicity risks. The major isoforms of CYP involved in the metabolism of warfarin sodium are CYP1A2 (for the R-warfarin) and CYP2C9 (for the S-warfarin). The probes for testing CYP1A2 are phenacetin and caffeine while for CYP2C9 tolbutamide. Although S-warfarin has major activity, it was decided to exclude its phenotyping for ethical issues, being mandatory to use a drug (tolbutamide). Instead, it was chosen to test the 1A2 isoform, as the activity of the latter isoform could be investigated by using caffeine contained in the caffeinated beverages. Specifically, a single-point concentration of salivary caffeine (total overnight salivary caffeine assessment [TOSCA]) after an overnight period of the caffeinated beverages abstinence was utilized. In the present study, 75 nonsmoker patients regularly receiving warfarin sodium were enrolled. The results have showed a significant association of the warfarin dose with TOSCA values (coefficient = -0.15, standard error = 0.04, 95% confidence interval = -0.24 to -0.06, t = -3.23, P = .002). In conclusion, the phenotyping of CYP1A2 by TOSCA could be useful, if further proven, to help manage patients on warfarin in order to lessen severe adverse events.
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Caffeine alters emotion and emotional responses in low habitual caffeine consumers.
Giles, GE, Spring, AM, Urry, HL, Moran, JM, Mahoney, CR, Kanarek, RB
Canadian journal of physiology and pharmacology. 2018;(2):191-199
Abstract
Caffeine reliably increases emotional arousal, but it is unclear whether and how it influences other dimensions of emotion such as emotional valence. These experiments documented whether caffeine influences emotion and emotion regulation choice and success. Low to abstinent caffeine consumers (maximum 100 mg/day) completed measures of state anxiety, positive and negative emotion, and salivary cortisol before, 45 min after, and 75 min after consuming 400 mg caffeine or placebo. Participants also completed an emotion regulation choice task, in which they chose to employ cognitive reappraisal or distraction in response to high and low intensity negative pictures (Experiment 1), or a cognitive reappraisal task, in which they employed cognitive reappraisal or no emotion regulation strategy in response to negative and neutral pictures (Experiment 2). State anxiety, negative emotion, and salivary cortisol were heightened both 45 and 75 min after caffeine intake relative to placebo. In Experiment 1, caffeine did not influence the frequency with which participants chose reappraisal or distraction, but reduced negativity of the picture ratings. In Experiment 2, caffeine did not influence cognitive reappraisal success. Thus, caffeine mitigated emotional responses to negative situations, but not how participants chose to regulate such responses or the success with which they did so.
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Physiologic changes of urinary proteome by caffeine and excessive water intake.
Peerapen, P, Ausakunpipat, N, Sutthimethakorn, S, Aluksanasuwan, S, Vinaiphat, A, Thongboonkerd, V
Clinical chemistry and laboratory medicine. 2017;(7):993-1002
Abstract
BACKGROUND Diurnal variations and physiologic changes of urinary proteome have been suggested in the urinary proteomics field. However, no clear evidence has been demonstrated. The present study thus aimed to define changes in urinary proteome by physiological stimuli, i.e. caffeine intake and excessive water drinking, both of which cause physiologic diuresis. METHODS Urine samples were collected from 30 healthy individuals under three different conditions: (i) morning void as the control; (ii) after drinking a cup of coffee; and (iii) after drinking 1 L of water within 20 min. Thereafter, differentially excreted proteins were analyzed by 2-DE proteomics approach and validated by Western blotting and ELISA. RESULTS Spot matching, quantitative intensity analysis, and ANOVA followed by Tukey's post-hoc multiple comparisons and the Bonferroni correction revealed significant differences in levels of five protein spots among three different conditions. These proteins were identified by quadrupole time-of-flight mass spectrometry (Q-TOF MS) and/or MS/MS analyses as kininogen 1 isoform 3, β-actin, prostaglandin D synthase (PGDS), fibrinogen α-chain and immunoglobulin light chain. Among these, the decreased level of immunoglobulin was successfully validated by Western blotting and ELISA. CONCLUSIONS These data indicated that caffeine intake and excessive water drinking could affect urinary excretion of some proteins and may affect urinary proteome analysis.