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Purpose: Ingested ethanol (EtOH) is metabolized gastrically and hepatically, which may influence resting and exercise metabolism. Previous exercise studies have provided EtOH intravenously rather than orally, altering the metabolic effects of EtOH. No studies to date have investigated the effects of EtOH ingestion on systemic and peripheral (e.g., skeletal muscle) exercise metabolism., Methods: Eight men (mean ± SD; age = 24 ± 5 yr, body mass = 76.7 ± 5.6 kg, height = 1.80 ± 0.04 m, V˙O2peak = 4.1 ± 0.2 L·min) performed two bouts of fasted cycling exercise at 55% V˙O2peak for 2 h, with (EtOH) and without (control) prior ingestion of EtOH 1 h and immediately before exercise (total dose = 0.1 g·kg lean body mass·h; 30.2 ± 1.1 g 40% ABV Vodka; fed in two equal boluses) in a randomized order, separated by 7-10 d., Results: Muscle glycogen use during exercise was not different between conditions (mean [normalized 95% confidence interval]; EtOH, 229 [156-302] mmol·kg dm, vs control, 258 [185-331] mmol·kg dm; P = 0.67). Mean plasma glucose concentrations during exercise were similar (control, 5.26 [5.22-5.30], vs EtOH, 5.34 [5.30-5.38]; P = 0.06). EtOH ingestion resulted in similar plasma nonesterified fatty acid concentrations compared with rest (control, 0.43 [0.31-0.55] mmol·L, vs EtOH, 0.30 [0.21-0.40] mmol·L) and during exercise. Plasma lactate concentration was higher during the first 30 min of rest after EtOH consumption (mean concentration; control, 0.83 [0.77-0.90] mmol·L, vs EtOH, 1.00 [0.93-1.07] mmol·L), but the response during exercise was similar between conditions., Conclusions: Muscle glycogen utilization was similar during exercise with or without prior EtOH ingestion, reflected in similar total whole-body carbohydrate oxidation rates observed.

Purpose: This study aims to examine whether muscle glycogen availability is associated with fatigue in a repeated exercise bout following short-term recovery., Methods: Ten endurance-trained individuals underwent two trials in a repeated-measures experimental design, each involving an initial run to exhaustion at 70% of VO2max (Run 1) followed by a 4-h recovery and a subsequent run to exhaustion at 70% of VO2max (Run 2). A low-carbohydrate (L-CHO; 0.3 g · kg body mass(-1) · h(-1)) or high-carbohydrate (H-CHO; 1.2 g · kg body mass(-1) · h(-1)) beverage was ingested at 30-min intervals during recovery. Muscle biopsies were taken upon cessation of Run 1, after recovery, and at exhaustion during Run 2 in L-CHO (F2). In H-CHO, muscle biopsies were obtained after recovery, at the time point coincident with fatigue in L-CHO (F2), and at the point of fatigue during the subsequent exercise bout (F3)., Results: Run 2 was more prolonged for participants on H-CHO (80 ± 16 min) than for participants on L-CHO (48 ± 11 min; P < 0.001). Muscle glycogen concentrations were higher at the end of recovery for participants on H-CHO (269 ± 84 mmol · kg dry mass(-1)) than for participants on L-CHO (157 ± 37 mmol · kg dry mass(-1); P = 0.001). The rate of muscle glycogen degradation during Run 2 was higher with H-CHO (3.1 ± 1.5 mmol · kg dry mass(-1) · min(-1)) than with L-CHO (1.6 ± 1.3 mmol · kg dry mass(-1) · min(-1); P = 0.05). The concentration of muscle glycogen was higher with H-CHO than with L-CHO at F2 (123 ± 28 mmol · kg dry mass(-1); P < 0.01), but no differences were observed between treatments at the respective points of exhaustion (78 ± 22 mmol · kg dry mass(-1) · min(-1 )for H-CHO vs 72 ± 21 mmol · kg dry mass(-1) · min(-1) for L-CHO)., Conclusion: Increasing carbohydrate intake during short-term recovery accelerates glycogen repletion in previously exercised muscles and thus improves the capacity for repeated exercise. The availability of skeletal muscle glycogen is therefore an important factor in the restoration of endurance capacity because fatigue during repeated exercise is associated with a critically low absolute muscle glycogen concentration.

Purpose: Antimicrobial peptides (AMPs) and toll-like receptors (TLRs) form part of the "chemical barrier" of the ocular surface to microbes. Evidence suggests that pathogen recognition by TLR releases AMPs, altering AMP-TLR profiles in pathological states. This study investigated ocular surface expression of AMP-TLRs in health and disease., Methods: Complementary DNA from conjunctival and corneal impression cytology samples was used for semiquantitative and quantitative polymerase chain reactions, to determine gene expression of 6 AMPs and TLRs-1-10, in healthy subjects and patients with bacterial (n = 6), viral (n = 6), Acanthamoeba (n = 3), or dry eye (n = 7) diseases., Results: Semiquantitative polymerase chain reaction showed variable AMP expression within groups and some expression patterns between groups, increased levels of LEAP (liver-expressed antimicrobial peptide)-1/hepcidin in viral disease, LEAP-2 in dry eye, and human beta defensin 3 in bacterial disease. There was no significant variability in TLR expression. Quantitative polymerase chain reaction showed significantly higher expression of LEAP-1 (P = 0.002) and TLR-8 (P = 0.023) and TLR-10 (P = 0.014) in viral keratitis and LEAP-2 (P = 0.034) in dry eye, versus controls., Conclusions: Increased expression of LEAP-1 and TLRs 8 and 10 in viral keratitis is novel; TLR-10 has not previously had a documented ligand. LEAP-2 may have a role in dry eye. Further studies will help to improve the understanding of these diseases and yield novel therapeutic interventions.

Purpose: To examine the influence of ingesting a carbohydrate-electrolyte (CHO-E) solution on muscle glycogen use and intermittent running capacity after consumption of a carbohydrate (CHO)-rich diet., Methods: Six male volunteers (mean +/- SD: age 22.7 +/- 3.4 yr; body mass (BM) 75.0 +/- 4.3 kg; V O2 max 60.2 +/- 1.6 mL x kg(-1) x min(-1)) performed two trials separated by 14 d in a randomized, crossover design. Subjects consumed either a 6.4% CHO-E solution or a placebo (PLA) in a double-blind fashion immediately before each trial (8 mL x kg(-1) BM) and at 15-min intervals (3 mL x kg(-1) BM) during intermittent high-intensity running to fatigue performed after CHO loading for 2 d. Muscle biopsy samples were obtained before exercise, after 90 min of exercise, and at fatigue., Results: Subjects ran longer in the CHO-E trial (158.0 +/- 28.4 min) compared with the PLA trial (131.0 +/- 19.7 min; P < 0.05). There were no differences in muscle glycogen use for the first 90 min of exercise (approximately 2 mmol of glucosyl units per kilogram of dry matter (DM) per minute). However, there was a trend for a greater use in the PLA trial after 90 min (4.2 +/- 2.8 mmol x kg(-1) DM x min(-1)) compared with the CHO-E trial (2.5 +/- 0.7 mmol x kg(-1) DM x min(-1); P = 0.10). Plasma glucose concentrations were higher at fatigue in the CHO-E than in the PLA trial (P < 0.001)., Conclusions: These results suggest that CHO-E ingestion improves endurance capacity during intermittent high-intensity running in subjects with high preexercise muscle glycogen concentrations. The greater endurance capacity cannot be explained solely by differences in muscle glycogen, and it may actually be a consequence of the higher plasma glucose concentration towards the end of exercise that provided a sustained source of CHO for muscle metabolism and for the central nervous system.

Purpose: This study aimed to investigate gender differences in i) pancreatic insulin secretory (beta-cell sensitivity) and whole body insulin sensitivity responses to an intravenous carbohydrate (CHO) load, and (ii) metabolic responses to exercise after both intravenous and oral CHO loads., Methods: Seven untrained healthy men and seven age-, body mass-, and VO2max-matched women performed two trials. In one trial they cycled for 60 min at 50% VO2max, starting 60 min after ingestion of a carbohydrate-rich meal (ME trial). In the other trial, subjects were infused with 20% dextrose solution to maintain blood glucose concentration at approximately 8 mmol x L(-1) for 60 min (INF trial), then the infusion rate was maintained constant during the following 60 min while exercising at 50% VO2max., Results: There was no gender effect on beta-cell sensitivity (serum insulin: 161 +/- 37 and 159 +/- 28 pmol x L(-1) for men and women, respectively) and whole body insulin sensitivity (155 +/- 24 and 135 +/- 29 mg x KgFFM(-1) x min(-1) per pmol x L(-1) x 100 for men and women, respectively). This may explain the similarity in glycemic, substrate oxidation and other metabolic responses to exercise after both intravenous and oral CHO loads in men and women., Conclusion: These results suggest that moderate exercise performed in the postprandial state presents a similar challenge to the ability of healthy, untrained men and women to perform exercise without a substantial decline in plasma glucose concentration below fasting values.