The percutaneous biopsy technique enables researchers and clinicians to collect skeletal muscle tissue samples. The technique is safe and highly effective. This video describes the percutaneous biopsy technique using a modified Bergström needle to obtain skeletal muscle tissue samples from the vastus lateralis of human subjects. The Bergström needle consists of an outer cannula with a small opening ('window') at the side of the tip and an inner trocar with a cutting blade at the distal end. Under local anesthesia and aseptic conditions, the needle is advanced into the skeletal muscle through an incision in the skin, subcutaneous tissue, and fascia. Next, suction is applied to the inner trocar, the outer trocar is pulled back, skeletal muscle tissue is drawn into the window of the outer cannula by the suction, and the inner trocar is rapidly closed, thus cutting or clipping the skeletal muscle tissue sample. The needle is rotated 90° and another cut is made. This process may be repeated three more times. This multiple cutting technique typically produces a sample of 100-200 mg or more in healthy subjects and can be done immediately before, during, and after a bout of exercise or other intervention. Following post-biopsy dressing of the incision site, subjects typically resume their activities of daily living right away and can fully participate in vigorous physical activity within 48-72 hr. Subjects should avoid heavy resistance exercise for 48 hr to reduce the risk of herniation of the muscle through the incision in the fascia. Video LinkThe video component of this article can be found at

Nieman DC, Shanely RA, Luo B, Meaney MP, Dew DA, Pappan KL. Metabolomics approach to assessing plasma 13-and 9-hydroxy-octadecadienoic acid and linoleic acid metabolite responses to 75-km cycling. Am J Physiol Regul Integr Comp Physiol 307: R68 -R74, 2014. First published April 23, 2014 doi:10.1152/ajpregu.00092.2014.-Bioactive oxidized linoleic acid metabolites (OXLAMs) include 13-and 9-hydroxy-octadecadienoic acid (13-HODE ϩ 9-HODE) and have been linked to oxidative stress, inflammation, and numerous pathological and physiological states. The purpose of this study was to measure changes in plasma 13-HODE ϩ 9-HODE following a 75-km cycling bout and identify potential linkages to linoleate metabolism and established biomarkers of oxidative stress (F2-isoprostanes) and inflammation (cytokines) using a metabolomics approach. Trained male cyclists (N ϭ 19, age 38.0 Ϯ 1.6 yr, wattsmax 304 Ϯ 10.5) engaged in a 75-km cycling time trial on their own bicycles using electromagnetically braked cycling ergometers (2.71 Ϯ 0.07 h). Blood samples were collected preexercise, immediately post-, 1.5 h post-, and 21 h postexercise, and analyzed for plasma cytokines (IL-6, IL-8, IL-10, tumor necrosis factor-␣, monocyte chemoattractant protein-1, granulocyte colonystimulating factor), F2-isoprostanes, and shifts in metabolites using global metabolomics procedures with gas chromatography mass spectrometry (GC-MS) and liquid chromatography mass spectrometry (LC-MS). 13-HODE ϩ 9-HODE increased 3.1-fold and 1.7-fold immediately post-and 1.5 h postexercise (both P Ͻ 0.001) and returned to preexercise levels by 21-h postexercise. Post-75-km cycling plasma levels of 13-HODE ϩ 9-HODE were not significantly correlated with increases in plasma cytokines but were positively correlated with postexercise F 2-isoprostanes (r ϭ 0.75, P Ͻ 0.001), linoleate (r ϭ 0.54, P ϭ 0.016), arachidate (r ϭ 0.77, P Ͻ 0.001), 12,13-dihydroxy-9Z-octadecenoate (12,13-DiHOME) (r ϭ 0.60, P ϭ 0.006), dihomo-linolenate (r ϭ 0.57, P ϭ 0.011), and adrenate (r ϭ 0.56, P ϭ 0.013). These findings indicate that prolonged and intensive exercise caused a transient, 3.1-fold increase in the stable linoleic acid oxidation product 13-HODE ϩ 9-HODE and was related to increases in F 2-isoprostanes, linoleate, and fatty acids in the linoleate conversion pathway. These data support the use of 13-HODE ϩ 9-HODE as an oxidative stress biomarker in acute exercise investigations.

Bananas and pears vary in sugar and phenolic profiles, and metabolomics was utilized to measure their influence on exercise performance and recovery. Male athletes (N = 20) cycled for 75 km while consuming water (WATER), bananas (BAN), or pears (PEAR) (0.6 g carbohydrate/kg each hour) in randomized order. UPLC-MS/MS and the library of purified standards maintained by Metabolon (Durham, NC) were used to analyze metabolite shifts in pre- and postexercise (0-h, 1.5-h, 21-h) blood samples. Performance times were 5.0% and 3.3% faster during BAN and PEAR versus WATER (P = 0.018 and P = 0.091, respectively), with reductions in cortisol, IL-10, and total leukocytes, and increases in blood glucose, insulin, and FRAP. Partial Least Square Discriminant Analysis (PLS-DA) showed a distinct separation between trials immediately (R(2)Y = 0.877, Q(2)Y = 0.457) and 1.5-h postexercise (R(2)Y = 0.773, Q(2)Y = 0.441). A total of 107 metabolites (primarily lipid-related) increased more than 2-fold during WATER, with a 48% and 52% reduction in magnitude during BAN and PEAR recovery (P < 0.001). Increases in metabolites unique to BAN and PEAR included fructose and fruit constituents, and sulfated phenolics that were related to elevated FRAP. These data indicate that BAN and PEAR ingestion improves 75-km cycling performance, attenuates fatty acid utilization and oxidation, and contributes unique phenolics that augment antioxidant capacity.

The lifespan of diabetic patients is 7-8 y shorter than that of the general population because of hyperglycemia-induced vascular complications and damage to other organs such as the liver and skeletal muscle. Here, we investigated the effects of epicatechin, one of the major flavonoids in cocoa, on health-promoting effects in obese diabetic (db/db) mice (0.25% in drinking water for 15 wk) and Drosophila melanogaster (0.01-8 mmol/L in diet). Dietary intake of epicatechin promoted survival in the diabetic mice (50% mortality in diabetic control group vs. 8.4% in epicatechin group after 15 wk of treatment), whereas blood pressure, blood glucose, food intake, and body weight gain were not significantly altered. Pathological analysis showed that epicatechin administration reduced the degeneration of aortic vessels and blunted fat deposition and hydropic degeneration in the liver caused by diabetes. Epicatechin treatment caused changes in diabetic mice that are associated with a healthier and longer lifespan, including improved skeletal muscle stress output, reduced systematic inflammation markers and serum LDL cholesterol, increased hepatic antioxidant glutathione concentration and total superoxide dismutase activity, decreased circulating insulin-like growth factor-1 (from 303 ± 21 mg/L in the diabetic control group to 189 ± 21 mg/L in the epicatechin-treated group), and improved AMP-activated protein kinase-α activity in the liver and skeletal muscle. Consistently, epicatechin (0.1-8 mmol/L) also promoted survival and increased mean lifespan of Drosophila. Therefore, epicatechin may be a novel food-derived, antiaging compound.

BackgroundUltrasound imaging is a valuable tool in exercise and sport science research, and has been used to visualize and track real-time movement of muscles and tendons, estimate hydration status in body tissues, and most recently, quantify skeletal muscle glycogen content. In this validation study, direct glycogen quantification from pre-and post-exercise muscle biopsy samples was compared with glycogen content estimates made through a portable, diagnostic high-frequency ultrasound and cloud-based software system (MuscleSound®, Denver, CO).MethodsWell-trained cyclists (N = 20, age 38.4 ± 6.0 y, 351 ± 57.6 wattsmax) participated in a 75-km cycling time trial on their own bicycles using CompuTrainer Pro Model 8001 trainers (RacerMate, Seattle, WA). Muscle biopsy samples and ultrasound measurements were acquired pre- and post-exercise. Specific locations on the vastus lateralis were marked, and a trained technician used a 12 MHz linear transducer and a standard diagnostic high resolution GE LOGIQ-e ultrasound machine (GE Healthcare, Milwaukee, WI) to make three ultrasound measurements. Ultrasound images were pre-processed to isolate the muscle area under analysis, with the mean pixel intensity averaged from the three scans and scaled (0 to 100 scale) to create the glycogen score. Pre- and post-exercise muscle biopsy samples were acquired at the vastus lateralis location (2 cm apart) using the suction-modified percutaneous needle biopsy procedure, and analyzed for glycogen content.ResultsThe 20 cyclists completed the 75-km cycling time trial in 168 ± 26.0 minutes at a power output of 193 ± 57.8 watts (54.2 ± 9.6% wattsmax). Muscle glycogen decreased 77.2 ± 17.4%, with an absolute change of 71.4 ± 23.1 mmol glycogen per kilogram of muscle. The MuscleSound® change score at the vastus lateralis site correlated highly with change in measured muscle glycogen content (R = 0.92, P < 0.001).ConclusionsMuscleSound® change scores acquired from an average of three ultrasound scans at the vastus lateralis site correlated significantly with change in vastus lateralis muscle glycogen content. These data support the use of the MuscleSound® system for accurately and non-invasively estimating exercise-induced decreases in vastus lateralis skeletal muscle glycogen content.