The aims of the present study were twofold: first to investigate whether TCA cycle intermediate (TCAI) pool expansion at the onset of moderate-intensity exercise in human skeletal muscle could be enhanced independently of pyruvate availability by ingestion of glutamine or ornithine alpha-ketoglutarate, and second, if it was, whether this modification of TCAI pool expansion had any effect on oxidative energy status during subsequent exercise. Seven males cycled for 10 min at approximately 70% maximal O2) uptake 1 h after consuming either an artificially sweetened placebo (5 ml/kg body wt solution, CON), 0.125 g/kg body wt L-(+)-ornithine alpha-ketoglutarate dissolved in 5 ml/kg body wt solution (OKG), or 0.125 g/kg body wt L-glutamine dissolved in 5 ml/kg body wt solution (GLN). Vastus lateralis muscle was biopsied 1 h postsupplement and after 10 min of exercise. The sum of four measured TCAI (SigmaTCAI; citrate, malate, fumarate, and succinate, approximately 85% of total TCAI pool) was not different between conditions 1 h postsupplement. However, after 10 min of exercise, SigmaTCAI (mmol/kg dry muscle) was greater in the GLN condition (4.90 +/- 0.61) than in the CON condition (3.74 +/- 0.38, P < 0.05) and the OKG condition (3.85 +/- 0.28). After 10 min of exercise, muscle phosphocreatine (PCr) content was significantly reduced (P < 0.05) in all conditions, but there was no significant difference between conditions. We conclude that the ingestion of glutamine increased TCAI pool size after 10 min of exercise most probably because of the entry of glutamine carbon at the level of alpha-ketoglutarate. However, this increased expansion in the TCAI pool did not appear to increase oxidative energy production, because there was no sparing of PCr during exercise.

The objectives of this study were to investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of single and multiple oral doses of ONO-7684, a novel activated factor XI (FXIa) inhibitor, in healthy subjects.Methods: This was a first-in-human (FIH), randomised, placebo-controlled, doubleblind, single and multiple dose study in healthy subjects under fed and fasted conditions. This study consisted of two parts: single ascending dose (Part A; 1, 5, 20, 80, 150 or 300 mg ONO-7684 or placebo) and multiple ascending doses (Part B; 80, 150 or 250 mg ONO-7684 or placebo daily for 14 days). In both parts, subjects were randomised in a 3:1 ratio to receive ONO-7684 or placebo.Results: ONO-7684 was well tolerated at all dose levels tested following both single and repeated doses, with a low overall incidence of treatment-emergent adverse events. There was no evidence to suggest a bleeding risk. Dose proportionality in exposure was observed for the range of 1-300 mg ONO-7684 in Part A. In Part A, the half-life of ONO-7684 administered in the fasted state ranged from 16.0 to 19.8 hours. In Part B, the half-life of ONO-7684 administered in the fed state ranged from 22.1 to 27.9 hours, supporting once daily oral dosing. ONO-7684 strongly inhibited factor XI coagulation activity (FXI:C) and increased activated partial thromboplastin time (aPTT), with a mean maximum on treatment percentage inhibition versus baseline of 92% and a mean maximum on treatment ratio-to-baseline of 2.78, respectively, at 250 mg ONO-7684 daily. Conclusions:The data generated in this FIH study demonstrate the promising potential of oral FXIa inhibition and ONO-7684 for indications requiring anticoagulation.

The tricarboxylic acid (TCA) cycle is the major final common pathway for oxidation of carbohydrates, lipids and some amino acids, which produces reducing equivalents in the form of nicotinamide adenine dinucleotide and flavin adenine dinucleotide that result in production of large amounts of adenosine triphosphate (ATP) via oxidative phosphorylation. Although regulated primarily by the products of ATP hydrolysis, in particular adenosine diphosphate, the rate of delivery of reducing equivalents to the electron transport chain is also a potential regulatory step of oxidative phosphorylation. The TCA cycle is responsible for the generation of approximately 67% of all reducing equivalents per molecule of glucose, hence factors that influence TCA cycle flux will be of critical importance for oxidative phosphorylation. TCA cycle flux is dependent upon the supply of acetyl units, activation of the three non-equilibrium reactions within the TCA cycle, and it has been suggested that an increase in the total concentration of the TCA cycle intermediates (TCAi) is also necessary to augment and maintain TCA cycle flux during exercise. This article reviews the evidence of the functional importance of the TCAi pool size for oxidative metabolism in exercising human skeletal muscle. In parallel with increased oxidative metabolism and TCA cycle flux during exercise, there is an exercise intensity-dependent 4- to 5-fold increase in the concentration of the TCAi. TCAi concentration reaches a peak after 10-15 minutes of exercise, and thereafter tends to decline. This seems to support the suggestion that the concentration of TCAi may be of functional importance for oxidative phosphorylation. However, researchers have been able to induce dissociations between TCAi pool size and oxidative energy provision using a variety of nutritional, pharmacological and exercise interventions. Brief periods of endurance training (5 days or 7 weeks) have been found to result in reduced TCAi pool expansion at the start of exercise (same absolute work intensity) in parallel with either equivalent or increased oxidative energy provision. Cycloserine inhibits alanine aminotransferase, which catalyses the predominant anaplerotic reaction in exercising human muscle. When infused into contracting rat hindlimb muscle, TCAi pool expansion was reduced by 25% with no significant change in oxidative energy provision or power output. Glutamine supplementation has been shown to enhance TCAi pool expansion at the start of exercise with no increase in oxidative energy provision. In summary, there is a consistent dissociation between the extent of TCAi pool expansion at the onset of exercise and oxidative energy provision. At the other end of the spectrum, the parallel loss of TCAi, glycogen and adenine nucleotides and accumulation of inosine monophosphate during prolonged exercise has led to the suggestion that there is a link between muscle glycogen depletion, reduced TCA cycle flux and the development of fatigue. However, analysis of serial biopsies during prolonge...

After exhaustive exercise, intravenous or oral glutamine promoted skeletal muscle glycogen storage. However, when glutamine was ingested with glucose polymer, whole-body carbohydrate storage was elevated, the most likely site being liver and not muscle, possibly due to increased glucosamine formation. The rate of tricarboxylic acid (TCA) cycle flux and hence oxidative metabolism may be limited by the availability of TCA intermediates. There is some evidence that intramuscular glutamate normally provides alpha-ketoglutarate to the mitochondrion. We hypothesized that glutamine might be a more efficient anaplerotic precursor than endogenous glutamate alone. Indeed, a greater expansion of the sum of muscle citrate, malate, fumarate and succinate concentrations was observed at the start of exercise (70% VO2(max)) after oral glutamine than when placebo or ornithine alpha-ketoglutarate was given. However, neither endurance time nor the extent of phosphocreatine depletion or lactate accumulation during the exercise was altered, suggesting either that TCA intermediates were not limiting for energy production or that the severity of exercise was insufficient for the limitation to be operational. We have also shown that in the perfused working rat heart, there is a substantial fall in intramuscular glutamine and alpha-ketoglutarate, especially after ischemia. Glutamine (but not glutamate, alpha-ketoglutarate or aspartate) was able to rescue the performance of the postischemic heart. This ability appears to be connected to the ability to sustain intracardiac ATP, phosphocreatine and glutathione.

Summary. When either a 960-kcal, 140-g carbohydrate meal, or a 75-g glucose load was ingested by non-diabetic Caucasians, the 2-h venous plasma glucose concentration was higher by 0.82 and 1.25 mmol/1, respectively, if the ambient temperature was 33 ~ rather than 23 ~ It is likely that this is a result of relative 'arterialisation' of the venous blood. Even at 23 ~ room temperature, use of the 'hot hand' technique to obtain 'arterialised' venous blood increases post-load glucose levels in contralateral antecubital veins. If these observations apply to those acclimatised to the heat, they could affect the diagnosis of both diabetes and impaired glucose tolerance in the tropics.

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SummaryBackground ONO‐2952 is a novel and selective inhibitor of translocator protein 18 kDa that reduces stress‐induced defecation and visceral hyperalgesia in rat models.AimTo evaluate the efficacy and safety of ONO‐2952 in females with irritable bowel syndrome with diarrhoea in an exploratory proof‐of‐concept study.MethodsA randomised, double‐blind, placebo‐controlled study was conducted at 49 US centres. Two hundred subjects with irritable bowel syndrome with diarrhoea (Rome III criteria) were randomised to ONO‐2952 20 mg, or 60 mg, or placebo. Subjects recorded irritable bowel syndrome symptoms daily during a 2‐week baseline period, the 4‐week treatment period and for 4 weeks post‐treatment. The co‐primary endpoints were change from baseline to week 4 in abdominal pain, stool consistency and stool frequency.ResultsImprovements in irritable bowel syndrome symptoms were seen with ONO‐2952 over placebo in per‐protocol analyses for all three co‐primary endpoints, but these did not reach statistical significance at the 5% level. The largest improvement was seen with ONO‐2952 60 mg. ONO‐2952 was well tolerated with a safety profile similar to that of placebo. Most adverse events were mild or moderate in severity and not treatment related.Conclusion ONO‐2952 showed evidence of clinical efficacy in reducing irritable bowel syndrome‐related symptoms in female subjects with irritable bowel syndrome with diarrhoea, and further evaluation is, therefore, warranted to assess its potential as a treatment for irritable bowel syndrome with diarrhoea (NCT01844180).

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