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Skeletal muscle blood flow

Arturo Figueroa, Alexei Wong, Salvador J Jaime, Joaquin U Gonzales
PURPOSE OF REVIEW: L-Citrulline, either synthetic or in watermelon, may improve vascular function through increased L-arginine bioavailability and nitric oxide synthesis. This article analyses potential vascular benefits of L-citrulline and watermelon supplementation at rest and during exercise. RECENT FINDINGS: There is clear evidence that acute L-citrulline ingestion increases plasma L-arginine, the substrate for endothelial nitric oxide synthesis. However, the subsequent acute improvement in nitric oxide production and mediated vasodilation is inconsistent, which likely explains the inability of acute L-citrulline or watermelon to improve exercise tolerance...
October 5, 2016: Current Opinion in Clinical Nutrition and Metabolic Care
Roberto A DE Blasi, Roberto Arcioni, Domitilla Brancadoro, Monica Rocco
BACKGROUND: Even though fluid loading is thought to improve organ perfusion, the way in which it does so remains unclear. We assessed how the microvascular bed in skeletal muscle reacts to passive leg raising in patients with and without sepsis or septic shock. METHODS: We studied 40 critically ill patients (group A) and 30 healthy controls (group B). The forearm microvascular bed was assessed using near-infrared spectroscopy before and after passive leg raising...
October 2016: Minerva Anestesiologica
W Kyle Mitchell, Bethan E Phillips, Daniel J Wilkinson, John P Williams, Debbie Rankin, Jonathan N Lund, Kenneth Smith, Philip J Atherton
Postprandial limb blood flow and skeletal muscle microvascular perfusion reduce with aging. Here we tested the impact of providing bolus essential amino acids (EAA) in the presence and absence of the nitric oxide precursor, l-Arginine (ARG), upon skeletal muscle blood flow and anabolism in older men. Healthy young (YOUNG: 19.7 ± 0.5 y, N = 8) and older men (OLD, 70 ± 0.8 y, N = 8) received 15 g EAA or (older only) 15 g EAA +3 g ARG (OLD-ARG, 69.2 ± 1.2 y, N = 8). We quantified responses in muscle protein synthesis (MPS; incorporation of (13)C phenylalanine into myofibrillar proteins), leg and muscle microvascular blood flow (Doppler/contrast enhanced ultrasound (CEUS)) and insulin/EAA in response to EEA ± ARG...
October 6, 2016: Clinical Nutrition: Official Journal of the European Society of Parenteral and Enteral Nutrition
Bart B L Groen, Astrid M Horstman, Henrike M Hamer, Michiel de Haan, Janneau van Kranenburg, Jörgen Bierau, Martijn Poeze, Will K W H Wodzig, Blake B Rasmussen, Luc J C van Loon
CONTEXT: Skeletal muscle protein synthesis is highly responsive to food intake. It has been suggested that the post-prandial increase in circulating insulin modulates the muscle protein synthetic response to feeding. OBJECTIVE: To investigate whether a greater post-prandial rise in circulating insulin level increases amino acid uptake in muscle and augments post-prandial muscle protein synthesis rates. PARTICIPANTS: and design. 48 healthy young (age 22±1 y; BMI 22...
July 19, 2016: Journal of Clinical Endocrinology and Metabolism
K T Cumming, S Ellefsen, B R Rønnestad, I Ugelstad, T Raastad
Blood flow restricted exercise (BFRE) with low loads has been demonstrated to induce considerable stress to exercising muscles. Muscle cells have developed a series of defensive systems against exercise-induced stress. However, little is known about acute and long-term effects of BFRE training on these systems. Nine previously untrained females trained low-load BFRE and heavy load strength training (HLS) on separate legs and on separate days to investigate acute and long-term effects on heat shock proteins (HSP) and endogenous antioxidant systems in skeletal muscles...
October 10, 2016: Scandinavian Journal of Medicine & Science in Sports
Ben Clark, Sarah Withers, Anthony Heagerty
OBJECTIVE: Resistance arteries significantly contribute to peripheral vascular resistance, and also determine insulin-sensitivity by controlling blood flow to skeletal muscle. Increased microvascular tone therefore facilitates the development of hypertension and insulin-resistance. Surrounding most blood vessels, perivascular adipose tissue (PVAT) exerts a vasorelaxant 'anti-contractile' effect. Few studies on skeletal muscle resistance arteries have investigated this vasorelaxant effect and the role of insulin...
September 2016: Journal of Hypertension
Y I Sun, Brian S Ferguson, Mmatthew J Rogatzki, James R McDonald, L Bruce Gladden
PURPOSE: The study aimed to examine the relationship between near-infrared spectroscopy (NIRS) signals and venous hemoglobin oxygen saturation (O2Hb%) and venous oxygen concentration (CvO2). METHODS: Gastrocnemius muscles (GS) in six dogs were surgically isolated and pump perfused. NIRS signals were recorded, and venous blood samples were collected at constant flow rates (control flow, high flow, and low flow) at rest as well as during electrically stimulated tetanic muscle contractions at rates of one contraction per 2 s (1/2 s) and two contractions per 3 s (2/3 s)...
October 2016: Medicine and Science in Sports and Exercise
Terezie Pelikánová
UNLABELLED: Diabetic retinopathy (DR) develops in patients with both type 1 and type 2 diabetes and is the major cause of vision loss and blindness in the working population. The main risk factor of DR is hyperglycemia accompanied by enhanced mitochondrial production of reactive oxygen species and oxidative stress, formation of advanced glycation end products (AGE) and hexosamines, increase in polyol metabolism of glucose. The severity of vascular injury depends on the individual genetic background and is modified by other epigenetic, metabolic and haemodynamic factors, including hypertension, dyslipidemia and oxidative stress...
2016: Vnitr̆ní Lékar̆ství
Jasdeep Kaur, Alberto Alvarez, Hanna W Hanna, Abhinav C Krishnan, Danielle Senador, Tiago M Machado, Yasir H Altamimi, Abe T Lovelace, Maryetta D Dombrowski, Marty D Spranger, Donal O'Leary
The muscle metaboreflex and arterial baroreflex regulate arterial pressure through distinct mechanisms. During submaximal exercise muscle metaboreflex activation (MMA) elicits a pressor response virtually solely by increasing cardiac output (CO) while baroreceptor unloading increases mean arterial pressure (MAP) primarily through peripheral vasoconstriction. The interaction between the two reflexes when activated simultaneously has not been well established. We activated the muscle metaboreflex in chronically instrumented canines during dynamic exercise (via graded reductions in hindlimb blood flow; HLBF) followed by simultaneous baroreceptor unloading (via bilateral carotid occlusion; BCO)...
September 9, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Shouyu Xu, Xueyun Liu, Zhenhuang Chen, Gaoquan Li, Qin Chen, Guoqing Zhou, Ruijie Ma, Xinmiao Yao, Xiao Huang
Blood flow restriction (BFR) under low-intensity resistance training (LIRT) can produce similar effects upon muscles to that of high-intensity resistance training (HIRT) while overcoming many of the restrictions to HIRT that occurs in a clinical setting. However, the potential molecular mechanisms of BFR induced muscle hypertrophy remain largely unknown. Here, using a BFR rat model, we aim to better elucidate the mechanisms regulating muscle hypertrophy as induced by BFR and reveal possible clinical therapeutic targets for atrophy cases...
December 15, 2016: Gene
Thais S Nobre, Ligia M Antunes-Correa, Raphaela V Groehs, Maria-Janieire N N Alves, Adriana O Sarmento, Aline Villa Nova Bacurau, Ursula Urias, Guilherme Barreto Alves, Maria Urbana P B Rondon, Patricia C Brum, Martino Martinelli, Holly R Middlekauff, Carlos E Negrao
Heart failure(HF) is characterized by decreased exercise capacity, attributable to neurocirculatory and skeletal muscle factors. Cardiac resynchronization therapy(CRT) and exercise training have each been shown to decrease muscle sympathetic nerve activity(MSNA) and increase exercise capacity in patients with HF. We hypothesized that exercise training in the setting of CRT would further reduce MSNA and vasoconstriction and would increase Ca(2+) handling gene expression in skeletal muscle in chronic systolic HF patients...
September 2, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Viktoras Silinskas, Albinas Grūnovas, Jurate Stanislovaitiene, Alfonsas Buliuolis, Eugenijus Trinkunas, Jonas Poderys
Electrical myostimulation (EMS) method is applied to improve skeletal muscle function. The aim of this study was to evaluate the efficacy of EMS applied to the sole and calf muscles on their strength and on maximal sprint performance. Each of 10 training sessions involved 10 s of stimulation and 50 s of rest for a total of 10 min. After the 10 training sessions, the maximal voluntary contraction (MVC) of right calf muscles increased by 6.0% from 830.0 ± 47.0 N to 878.0 ± 45.3 N (P < 0.05). When EMS was applied to trained athletes, their 10-m sprint performance improved by 2...
August 26, 2016: Journal of Strength and Conditioning Research
Steven A Romero, Jennifer L McCord, Matthew R Ely, Dylan C Sieck, Tahisha M Buck, Meredith J Luttrell, David A MacLean, John R Halliwill
In humans, acute aerobic exercise elicits a sustained post-exercise vasodilation within previously active skeletal muscle. This response is dependent on activation of histamine H1 and H2 receptors, but the source of intramuscular histamine remains unclear. We tested the hypothesis that interstitial histamine in skeletal muscle would be increased with exercise and would be dependent on de novo formation via the inducible enzyme histidine decarboxylase and/or mast cell degranulation. Subjects performed 1 h of unilateral dynamic knee-extension exercise or sham (seated rest)...
August 25, 2016: Journal of Applied Physiology
Crystal L Coolbaugh, Emily C Bush, Charles F Caskey, Bruce M Damon, Theodore F Towse
Automated software improves the accuracy and reliability of blood velocity, vessel diameter, blood flow, and shear rate ultrasound measurements, but existing software offers limited flexibility to customize and validate analyses. We developed FloWave.US-open-source software to automate ultrasound blood flow analysis-and demonstrated the validity of its blood velocity (aggregate relative error, 4.32%) and vessel diameter (0.31%) measures with a skeletal muscle ultrasound flow phantom. Compared with a commercial, manual analysis software program, FloWave...
October 1, 2016: Journal of Applied Physiology
Matthew R Ely, Steven A Romero, Dylan C Sieck, Joshua E Mangum, Meredith J Luttrell, John R Halliwill
Histamine contributes to elevations in skeletal muscle blood flow following exercise, which raises the possibility that histamine is an important mediator of the inflammatory response to exercise. We examined the influence of antihistamines on post-exercise blood flow, inflammation, muscle damage, and delayed onset muscle soreness (DOMS) in a model of moderate exercise-induced muscle damage. Subjects consumed either a combination of fexofenadine and ranitidine (blockade, n=12) or nothing (control, n=12) before 45 min of downhill running (-10% grade)...
August 4, 2016: Journal of Applied Physiology
Jerrold Petrofsky, Lee Berk, Gurinder Bains, Iman Akef Khowailed, Haneul Lee, Michael Laymon
OBJECTIVE: To assess the impact of heat applied for 8 hours immediately after or 24 hours after exercise on delayed-onset muscle soreness (DOMS) in large skeletal muscle groups measured by subjective and objective means. DESIGN: Cross-sectional repeated measure design study. SETTING: Research laboratory. SUBJECTS: Three groups of 20 subjects, age range 20 to 40 years. INTERVENTION: Squats were conducted in three 5-minute bouts to initiate DOMS; 3 minutes of rest separated the bouts...
July 21, 2016: Clinical Journal of Sport Medicine: Official Journal of the Canadian Academy of Sport Medicine
John R A Shepherd, Michael J Joyner, Frank A Dinenno, Timothy B Curry, Sushant M Ranadive
In humans, intra-arterial ATP infusion in limbs mimics many features of exercise hyperemia. However, it remains unknown whether ATP can evoke the prolonged vasodilation seen during exercise. Therefore, we addressed two questions during a continuous 3-h brachial artery infusion of ATP [20 μg·100 ml forearm volume (FAV)(-1)·min(-1)]: 1) would skeletal muscle blood flow remain robust or wane over time (tachyphylaxis); and 2) would the hyperemic response to moderate-intensity exercise performed during the ATP administration be blunted compared with that during control (saline) infusion...
September 1, 2016: Journal of Applied Physiology
Scott K Ferguson, Clark T Holdsworth, Trenton D Colburn, Jennifer L Wright, Jesse C Craig, Alex Fees, Andrew M Jones, Jason D Allen, Timothy I Musch, David C Poole
Chronic heart failure (CHF) results in central and peripheral derangements that ultimately reduce skeletal muscle O2 delivery and impair exercise tolerance. Dietary nitrate (NO3 (-)) supplementation improves skeletal muscle vascular function and tolerance to exercise. We tested the hypothesis that NO3 (-) supplementation would elevate exercising skeletal muscle blood flow (BF) and vascular conductance (VC) in CHF rats. Myocardial infarction (MI) was induced (coronary artery ligation) in young adult male rats...
September 1, 2016: Journal of Applied Physiology
Timothy P Just, Ian R Cooper, Darren S DeLorey
No abstract text is available yet for this article.
October 2016: Exercise and Sport Sciences Reviews
Erin R Mandel, Cassandra Uchida, Emmanuel Nwadozi, Armin Makki, Tara L Haas
Remodeling of the skeletal muscle microvasculature involves the coordinated actions of matrix metalloproteinases (MMPs) and their endogenous inhibitors, tissue inhibitor of metalloproteinases (TIMPs). We hypothesized that the loss of TIMP1 would enhance both ischemia and flow-induced vascular remodeling by increasing MMP activity. TIMP1 deficient (Timp1(-/-) ) and wild-type (WT) C57BL/6 mice underwent unilateral femoral artery (FA) ligation or were treated with prazosin, an alpha-1 adrenergic receptor antagonist, in order to investigate vascular remodeling to altered flow...
July 19, 2016: Journal of Cellular Physiology
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