title: Passive leg movement enhances interstitial VEGF protein, endothelial cell proliferation, and eNOS mRNA content in human skeletal muscle.
abstract: The present study used passive limb movement as an experimental model to study the effect of increased blood flow and passive stretch, without enhanced metabolic demand, in young healthy male subjects. The model used was 90 min of passive movement of the leg leading to a 2.8-fold increase (P < 0.05) in blood flow without a significant enhancement in oxygen uptake. Muscle interstitial fluid was sampled with microdialysis technique and analyzed for vascular endothelial growth factor (VEGF) protein and for the effect on endothelial cell proliferation. Biopsies obtained from the musculus vastus lateralis were analyzed for mRNA content of VEGF, endothelial nitric oxide synthase (eNOS), and matrix metalloproteinase-2 (MMP-2). The passive leg movement caused an increase (P < 0.05) in interstitial VEGF protein concentration above rest (73 +/- 21 vs. 344 +/- 83 pg/ml). Addition of muscle dialysate to cultured endothelial cells revealed that dialysate obtained during leg movement induced a 3.2-fold higher proliferation rate (P < 0.05) than dialysate obtained at rest. Passive movement also enhanced (P < 0.05) the eNOS mRNA level fourfold above resting levels. VEGF mRNA and MMP-2 mRNA levels were unaffected. The results show that a session of passive leg movement, elevating blood flow and causing passive stretch, augments the interstitial concentrations of VEGF, the proliferative effect of interstitial fluid, and eNOS mRNA content in muscle tissue. We propose that enhanced blood flow and passive stretch are positive physiological stimulators of factors associated with capillary growth in human muscle.
authors: Copenhagen Muscle Research Center, Department of Exercise and Sport Sciences, Section of Human Physiology, University of Copenhagen, DK-2100 Copenhagen, Denmark. yhellsten@aki.ku.dk
authors: Ylva
authors: Y
authors: Hellsten
authors: Nora
authors: N
authors: Rufener
authors: Jens J
authors: JJ
authors: Nielsen
authors: Birgitte
authors: B
authors: Høier
authors: Peter
authors: P
authors: Krustrup
authors: Jens
authors: J
authors: Bangsbo
mesh_terms: D000328:Adult; D049109:Cell Proliferation; D042783:Endothelial Cells / Q000502:physiology*; D045604:Extracellular Fluid / Q000201:enzymology; D006801:Humans; D007773:Lactates / Q000097:blood; D007866:Leg / Q000098:blood supply / Q000502:physiology*; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis; D017551:Microdialysis; D009068:Movement / Q000502:physiology*; D018482:Muscle, Skeletal / Q000098:blood supply / Q000166:cytology / Q000502:physiology*; D052250:Nitric Oxide Synthase Type III / Q000096:biosynthesis*; D010101:Oxygen Consumption / Q000502:physiology; D011188:Potassium / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D012039:Regional Blood Flow / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis*
chemical_list: D007773:Lactates; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D052250:Nitric Oxide Synthase Type III; D020778:Matrix Metalloproteinase 2; D011188:Potassium