Study on the diagnosis of gout with xanthine and hypoxanthine.

BACKGROUND: Hyperuricemia is the only biochemical index in the classification of acute gouty arthritis in American Rheumatism Association 1977 and the main basis of clinical diagnosis for most doctors. However, nearly half of the time gout occurs without hyperuricemia, especially in an acute attack，which leads to an urgent need to find a new substitute diadynamic criteria of gout. Xanthine and hypoxanthine, as precursors of uric acid, have been reported to be high in gout patients with hyperuricemia and presumed to be gout biomarkers. OBJECTIVES: To further explore the possibility of xanthine and hypoxanthine to be gout biomarkers as substitutes for uric acid. METHODS: A reversed-phase HPLC-UV method was employed for simultaneous quantitative detection of uric acid (UA), xanthine (X), and hypoxanthine (HX) in gout patients' (with and without hyperuricemia) and healthy persons' serum. RESULTS: The xanthine and hypoxanthine concentrations in gout patients with hyperuricemia and without hyperuricemia are higher than in healthy persons with a P < 0.001. CONCLUSIONS: This study supplements previous researches by confirming that xanthine and hypoxanthine are significantly elevated in gout patients' serum especially in patients' with normouricemia, which supported xanthine and hypoxanthine may have clinical application for the diagnosis of gout.

Active Acupoints Differ from Inactive Acupoints in Modulating Key Plasmatic Metabolites of Hypertension: A Targeted Metabolomics Study.

The effect of active acupoints versus inactive acupoints in treating hypertension is not well documented. Metabolic phenotypes, depicted by metabolomics analysis, reflect the influence of external exposures, nutrition, and lifestyle on the integrated system of the human body. Therefore, we utilized high-performance liquid chromatography tandem mass spectrometry to compare the targeted metabolic phenotype changes induced by two different acupoint treatments. The clinical outcomes show that active acupoint treatment significantly lowers 24-hour systolic blood pressure but not diastolic blood pressure, as compared with inactive acupoint treatment. Furthermore, distinctive changes are observed between the metabolomics data of the two groups. Multivariate analysis shows that only in the active acupoint treatment group can the follow-up plasma be clearly separated from the baseline plasma. Moreover, the follow-up plasma of these two groups can be clearly separated, indicating two different post-treatment metabolic phenotypes. Three metabolites, sucrose, cellobiose, and hypoxanthine, are shown to be the most important features of active acupoint treatment. This study demonstrates that metabolomic analysis is a potential tool that can be used to efficiently differentiate the effect of active acupoints from inactive acupoints in treating hypertension. Possible mechanisms are the alternation of hypothalamic microinflammation and the restoration of host-gut microbiota interactions induced by acupuncture.

Contribution of branched-chain amino acids to purine nucleotide cycle: a pilot study.

BACKGROUND/OBJECTIVES: Branched-chain amino acids (BCAAs) and purine nucleotide cycle (PNC) are both associated with energy metabolism. The purpose of this study was to explore the influences of BCAA supplementation on the PNC activity of male athletes in response to a bout of endurance running exercise. SUBJECTS/METHODS: Twelve male athletes (20.3±1.4 years) participated in the study. Each of the athletes received 12 g of a BCAA supplement (leucine 54%, isoleucine 19% and valine 27%) per day during the study. They performed two identical 60-min running exercises (65-70% maximum heart rate reserved) before and after receiving the BCAA supplements for 15 days. In addition to body composition measurement, plasma and urinary samples were also collected. Plasma samples were examined for the concentrations of glucose, lactate, BCAAs, alanine, glutamine, aspartate, hypoxanthine and uric acid. Urinary samples were examined for the concentrations of urea nitrogen, hydroxyproline, 3-methylhistidine and creatinine. RESULTS: Body composition and the concentrations of urinary metabolites were not affected by BCAA supplementation, whereas clearance of plasma lactate after recovery from exercise was enhanced by BCAA supplementation (P<0.05). Plasma aspartate concentration was increased (P<0.05), whereas plasma glutamine, hypoxanthine and uric acid concentrations were decreased (P<0.05) by BCAA supplementation. CONCLUSIONS: The findings suggest that BCAA supplements not only provided additional substrate to meet the energy demands of the athletes during endurance exercise but also reduced their PNC activity, and subsequently decreased uric acid production and reduced the incidence of gout in a person engaging in endurance exercise.

Exercise-induced oxidative stress in elderly subjects: the effect of red orange supplementation on the biochemical and cellular response to a single bout of intense physical activity.

Aging is characterized by an impaired capacity to maintain the redox balance both in physiological and pathological situations associated with an increased production of reactive oxygen species. Since the extent of this phenomenon may be influenced by an antioxidants-rich diet, we investigated the effect of supplementation with fresh red orange juice (ROJ) on biochemical and cellular biomarkers of oxidative stress in healthy, trained elderly women after a single bout of exhaustive exercise (EE). To this purpose, a sample of 22 females, 15 (69.0 ± 5.1 years) taking the ROJ supplementation and 7 (68.1 ± 2.7 years) as Control group, was constituted. Blood samples were collected immediately before, 30 minutes, and 24 hr after a single bout of EE, at baseline and after 4 weeks. Our results demonstrate that markers of DNA damage or apoptosis were not affected by EE both in Control and ROJ group, and by ROJ, whereas, exercise temporarily affected the redox balance in both groups. Controls didn't change their response to EE after the experimental period, but experimental group after ROJ supplementation had lower EE-induced MDA, consumed less ascorbic acid, and had less activation of the hypoxanthine/xanthine system, i.e., they seemed to be protected from hypoxia/reoxygenation mechanisms.

Coenzyme Q10 supplementation and exercise-induced oxidative stress in humans.

OBJECTIVE: The theoretically beneficial effects of coenzyme Q10 (Q10) on exercise-related oxidative stress and physical capacity have not been confirmed to our knowledge by interventional supplementation studies. Our aim was to investigate further whether Q10 supplementation at a dose recommended by manufacturers influences these factors. METHODS: Using a randomized, double-blind, controlled design, we investigated the effect on physical capacity of 8 wk of treatment with a daily dose of 90 mg of Q10 (n = 12) compared with placebo (n = 11) in moderately trained healthy men 19 to 44 y old. Two days of individualized performance tests to physical exhaustion were performed before and after the intervention. Primary outcomes were maximal oxygen uptake, workload, and heart rate at the lactate threshold. Secondary outcomes were creatine kinase, hypoxanthine, and uric acid. RESULTS: No significant differences between the groups were discerned after the intervention for maximal oxygen uptake (-0.11 L/min, 95% confidence interval -0.31 to 0.08, P = 0.44), workload at lactate threshold (6.3 W, -13.4 to 25.9, P = 0.36), or heart rate at lactate threshold (2.0 beats/min, -4.9 to 8.9, P = 0.41). No differences between the groups were detected for hypoxanthine or uric acid (serum markers of oxidative stress) or creatine kinase (a marker of skeletal muscle damage). CONCLUSION: Although in theory Q10 could be beneficial for exercise capacity and in decreasing oxidative stress, the present study could not demonstrate that such effects exist after supplementation with a recommended dose.

Metabolomic study of myocardial ischemia and intervention effects of Compound Danshen Tablets in rats using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry.

Myocardial ischemia (MI) is a worldwide epidemic. Compound Danshen Tablets (CDTs), an herbal compound preparation, are widely used to treat MI in China. In this study, we aimed to explore novel biomarkers to increase the understanding of MI and investigate therapeutic mechanisms of CDT by using a metabolomic approach. Plasma extracts from sham, MI model, CDT- and western medicines (isosorbide dinitrate, verapamil, propranolol, captopril, and trimethazine)-treated rats were analyzed by ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). The orthogonal partial least square (OPLS) model was built to find metabolites expressed in significantly different amounts between MI and sham rats. Meanwhile, partial least squares discriminant analysis (PLS-DA) was used to investigate CDT's protective effects. The results showed that CDT presented protective effects on MI by reversing potential biomarkers to sham levels, especially for the four metabolites in the pathway of purine metabolism (hypoxanthine, xanthine, inosine and allantoin).

Responses of criterion variables to different supplemental doses of L-carnitine L-tartrate.

L-carnitine L-tartrate (LCLT) supplementation beneficially affects markers of postexercise metabolic stress and muscle damage. However, to date, no study has determined the dose response of LCLT to elicit such responses. Therefore, the purpose of this study was to determine the effects of different doses of LCLT on criterion variables previously shown to be responsive to LCLT supplementation. Eight healthy men (22 +/- 3 y, 174 +/- 5 cm, 83.0 +/- 15.3 kg) were supplemented with 0 g, 1 g, and 2 g of LCLT for 3 weeks and then performed a bout of resistance exercise (5 sets of 15-20 repetition maximum with a 2-min rest between sets) with associated blood draws. This procedure was performed in a balanced, randomized, repeated measures design. Serum carnitine concentrations increased (p < or = 0.05) following the 1 g and 2 g doses, with the 2-g dose providing the highest carnitine concentrations. The 1- and 2-g doses reduced postexercise serum hypoxanthine, serum xanthine oxidase, serum myoglobin, and perceived muscle soreness. In conclusion, both the 1- and 2-g doses were effective in mediating various markers of metabolic stress and of muscle soreness. Use of LCLT appears to attenuate metabolic stress and the hypoxic chain of events leading to muscle damage after exercise.

Effect of sauna bathing and beer ingestion on plasma concentrations of purine bases.

To determine whether sauna bathing alone or in combination with beer ingestion increases the plasma concentration of uric acid, 5 healthy subjects were tested. Urine and plasma measurements were performed before and after each took a sauna bath, ingested beer, and ingested beer just after taking a sauna bath, with a 2-week interval between each activity. Sauna bathing alone increased the plasma concentrations of uric acid and oxypurines (hypoxanthine and xanthine), and decreased the urinary and fractional excretion of uric acid, while beer ingestion alone increased the plasma concentrations and urinary excretion of uric acid and oxypurines. A combination of both increased the plasma concentration of uric acid and oxypurines, and decreased the urinary and fractional excretion of uric acid, with an increase in the urinary excretion of oxypurines. The increase in plasma concentration of uric acid with the combination protocol was not synergistic as compared to the sum of the increases by each alone. Body weight, urine volume, and the urinary excretion of sodium and chloride via dehydration were decreased following sauna bathing alone. These results suggest that sauna bathing had a relationship with enhanced purine degradation and a decrease in the urinary excretion of uric acid, leading to an increase in the plasma concentration of uric acid. Further, we concluded that extracellular volume loss may affect the common renal transport pathway of uric acid and xanthine. Therefore, it is recommended that patients with gout refrain from drinking alcoholic beverages, including beer, after taking a sauna bath, since the increase in plasma concentration of uric acid following the combination of sauna bathing and beer ingestion was additive.

Effect of ribose supplementation on resynthesis of adenine nucleotides after intense intermittent training in humans.

The effect of oral ribose supplementation on the resynthesis of adenine nucleotides and performance after 1 wk of intense intermittent exercise was examined. Eight subjects performed a random double-blind crossover design. The subjects performed cycle training consisting of 15 x 10 s of all-out sprinting twice per day for 7 days. After training the subjects received either ribose (200 mg/kg body wt; Rib) or placebo (Pla) three times per day for 3 days. An exercise test was performed at 72 h after the last training session. Immediately after the last training session, muscle ATP was lowered (P < 0.05) by 25 +/- 2 and 22 +/- 3% in Pla and Rib, respectively. In both Pla and Rib, muscle ATP levels at 5 and 24 h after the exercise were still lower (P < 0.05) than pretraining. After 72 h, muscle ATP was similar (P > 0.05) to pretraining in Rib (24.6 +/- 0.6 vs. 26.2 +/- 0.2 mmol/kg dry wt) but still lower (P < 0.05) in Pla (21.1 +/- 0.5 vs. 26.0 +/- 0.2 mmol/kg dry wt) and higher (P < 0.05) in Rib than in Pla. Plasma hypoxanthine levels after the test performed at 72 h were higher (P < 0.05) in Rib compared with Pla. Mean and peak power outputs during the test performed at 72 h were similar (P > 0.05) in Pla and Rib. The results support the hypothesis that the availability of ribose in the muscle is a limiting factor for the rate of resynthesis of ATP. Furthermore, the reduction in muscle ATP observed after intense training does not appear to be limiting for high-intensity exercise performance.

Energy demands during a judo match and recovery.

OBJECTIVE: To assess energy demand during a judo match and the kinetics of recovery by measuring the metabolites of the oxypurine cascade, lipolytic activity, and glycolytic pathway. METHODS: Venous blood samples were taken from 16 national judoists (mean (SEM) age 18.4 (1.6) years), before (T(1)) and three minutes (T(2)), one hour (T(3)), and 24 hours (T(4)) after a match. A seven day diet record was used to evaluate nutrient intake. RESULTS: Nutrient analysis indicated that these athletes followed a low carbohydrate diet. Plasma lactate concentration had increased to 12.3 (1.8) mmol/l at the end of the match. An increase in the levels of extracellular markers of muscle adenine nucleotide catabolism, urea, and creatinine was observed at T(2), while uric acid levels remained unchanged. High concentrations of urea persisted for 24 hours during the recovery period. Ammonia, hypoxanthine, xanthine, and creatinine returned to control levels within the 24 hour recovery period. Uric acid concentrations rose from T(3) and had not returned to baseline 24 hours after the match. The levels of triglycerides, glycerol, and free fatty acids had increased significantly (p<0.05) after the match (T(2)) but returned to baseline values within 24 hours. Concentrations of high density lipoprotein cholesterol and total cholesterol were significantly increased after the match. CONCLUSIONS: These results show that a judo match induces both protein and lipid metabolism. Carbohydrate availability, training adaptation, and metabolic stress may explain the requirement for these types of metabolism.

Effect of creatine supplementation on muscle metabolic response to a maximal treadmill exercise test in Standardbred horses.

The aim of the present study was to investigate the effect of creatine (Cr) supplementation on muscle metabolic response in connection with a maximal treadmill exercise test, known to cause a marked anaerobic metabolic response and adenine nucleotide degradation. First, 6 Standardbred trotters performed a standardised maximal exercise test until fatigue (baseline test). The test used was an inclined incremental treadmill test in which the speed was increased by 1 m/s, starting at 7 m/s, every 60 s until the horse could no longer keep pace with the treadmill. After this baseline test, the horses were separated into 2 equal groups. One half received a dose of 25 g creatine monohydrate twice daily, and the other group were given the same dose of lactose (placebo). The supplementation period was 6.5 days, after which the maximal treadmill exercise test was performed again. A washout period of 14 days was allowed before treatments were switched between groups and a new supplementation period started. After this second supplementation period a new maximal exercise test was performed. After supplementation with creatine or placebo, horses were stopped after performing the same number of speed steps and duration of exercise as they had in the baseline test. Blood samples for analysis of plasma lactate, creatine (Cr), creatinine, hypoxanthine, xanthine and uric acid concentrations were collected at rest, during each speed step and during recovery. The total blood volume (TBV) was also determined. Muscle biopsies for analysis of muscle metabolites (adenosine triphosphate [ATP], adenosine diphosphate [ADP], adenosine monophosphate [AMP], inosine monophosphate [IMP], creatine phosphate [CP], lactate [La] and glycogen) were taken at rest, immediately post exercise and after 15 min recovery. The results showed no significant increase in plasma Cr or muscle total creatine concentration (TCr) after supplementation with Cr. At the end of exercise ATP and CP concentrations had decreased and IMP and lactate concentrations increased in muscle in all groups. Plasma lactate concentration increased during exercise and recovery and plasma uric acid concentration increased during recovery in all groups. No influence could be found in TBV after supplementation with creatine. These results show that creatine supplementation in the dosage used in this study had no influence on muscle metabolic response or TBV.

Oral creatine supplementation decreases plasma markers of adenine nucleotide degradation during a 1-h cycle test.

We investigated the effect of oral creatine supplementation (20 g d(-1) for 7 days) on metabolism during a 1-h cycling performance trial. Twenty endurance-trained cyclists participated in this double-blind placebo controlled study. Five days after familiarization with the exercise test, the subjects underwent a baseline muscle biopsy. Thereafter, a cannula was inserted into a forearm vein before performing the baseline maximal 1-h cycle (test 1 (T1)). Blood samples were drawn at regular intervals during exercise and recovery. After creatine (Cr) loading, the muscle biopsy, 1-h cycling test (test 2 (T2)) and blood sampling were repeated. Resting muscle total creatine (TCr), measured by high performance liquid chromatography, was increased (P < 0.001) in the creatine group from 123.0 +/- 3.8 - 159.8 +/- 7.9 mmol kg(-1) dry wt, but was unchanged in the placebo group (126.7 +/- 4.7 - 127.5 +/- 3.6 mmol kg(-1) dry wt). The extent of Cr loading was unrelated to baseline Cr levels (r=0.33, not significant). Supplementation did not significantly improve exercise performance (Cr group: 39.1 +/- 0.9 vs. 39.8 +/- 0.8 km and placebo group: 39.3 +/- 0.8 vs. 39.2 +/- 1.1 km) or change plasma lactate concentrations. Plasma concentrations of ammonia (NH(3)) (P < 0.05) and hypoxanthine (Hx) (P < 0.01) were lower in the Cr group from T1 to T2. Our results indicate that Cr supplementation alters the metabolic response during sustained high-intensity submaximal exercise. Plasma data suggest that nett intramuscular adenine nucleotide degradation may be decreased in the presence of enhanced intramuscular TCr concentration even during submaximal exercise.

Effect of Q10 supplementation on tissue Q10 levels and adenine nucleotide catabolism during high-intensity exercise.

The aim of the present study was to investigate the concentration of ubiquinone-10 (Q10), at rest, in human skeletal muscle and blood plasma before and after a period of high-intensity training with or without Q10 supplementation. Another aim was to explore whether adenine nucleotide catabolism, lipid peroxidation, and mitochondrial function were affected by Q10 treatment. Seventeen young healthy men were assigned to either a control (placebo) or Q10-supplementation (120 mg/day) group. Q10 supplementation resulted in a significantly higher plasma Q10/total cholesterol level on Days 11 and 20 compared with Day 1. There was no significant change in the concentration of Q10 in skeletal muscle or in isolated skeletal muscle mitochondria in either group. Plasma hypoxanthine and uric acid concentrations increased markedly after each exercise test session in both groups. After the training period, the postexercise increase in plasma hypoxanthine was markedly reduced in both groups, but the response was partially reversed after the recovery period. It was concluded that Q10 supplementation increases the concentration of Q10 in plasma but not in skeletal muscle.

Effect of creatine supplementation on sprint exercise performance and muscle metabolism.

The aim of the present study was to examine the effect of creatine supplementation (CrS) on sprint exercise performance and skeletal muscle anaerobic metabolism during and after sprint exercise. Eight active, untrained men performed a 20-s maximal sprint on an air-braked cycle ergometer after 5 days of CrS [30 g creatine (Cr) + 30 g dextrose per day] or placebo (30 g dextrose per day). The trials were separated by 4 wk, and a double-blind crossover design was used. Muscle and blood samples were obtained at rest, immediately after exercise, and after 2 min of passive recovery. CrS increased the muscle total Cr content (9.5 +/- 2.0%, P < 0.05, mean +/- SE); however, 20-s sprint performance was not improved by CrS. Similarly, the magnitude of the degradation or accumulation of muscle (e.g., adenine nucleotides, phosphocreatine, inosine 5'-monophosphate, lactate, and glycogen) and plasma metabolites (e.g. , lactate, hypoxanthine, and ammonia/ammonium) were also unaffected by CrS during exercise or recovery. These data demonstrated that CrS increased muscle total Cr content, but the increase did not induce an improved sprint exercise performance or alterations in anaerobic muscle metabolism.