title: The effect of intermittent pneumatic compression of legs on the levels of nitric oxide related species in blood and on arterial function in the arm.
abstract: BACKGROUND
  Intermittent pneumatic compression (IPC) of legs exerts beneficial local vascular effects, possibly through local release of nitric oxide (NO). However, studies demonstrating systemic transport of nitrogen oxide species and release of NO prompt the question of whether IPC could also exert nonlocal effects. We tested whether IPC (1) affects systemic levels of nitrite, S-nitrosothiols and red blood cell (RBC) NO, and (2) exerts vasoactive effects in the brachial artery (BA), although this hypothesis-generating pilot study did not investigate cause and effect relationship between (1) and (2).
  
  
  METHODS
  In 10 healthy subjects, ages 24-39 years, we measured plasma nitrite, plasma S-nitrosothiols and RBC-NO from venous blood samples drawn before and after IPC treatment. We also measured BA responses to 5 min of upper arm occlusion at rest and during 1 h of leg IPC.
  
  
  RESULTS
  There was a significant decrease in plasma nitrite (112±26 nM to 90±15 nM, p=0.0008) and RBC-NO (129±72 nM to 102±41 nM, p=0.02). Plasma S-nitrosothiols were unchanged (5.79±4.81 nM to 6.27±5.79 nM, p=0.3). BA occlusion-mediated constriction (OMC) was significantly attenuated with IPC treatment (-43±13% to -33±12%, p=0.003). High-flow mediated BA dilation was unchanged (13.3±9.4% to 11.5±7.2%, p=0.2).
  
  
  CONCLUSIONS
  Plasma nitrite, RBC-NO, and BA OMC decreased with leg IPC. We hypothesize that this decrease in circulatory pool of plasma nitrite and RBC-NO may result from the transfer of their NO-bioactivity from blood to the hypoxic arm tissue, to be stored and released under hypoxic stress and oppose OMC. Future studies should investigate whether IPC-induced decreases in brachial OMC are caused by the changes in systemic NO activity, and whether leg IPC could benefit distant arterial function in systemic cardiovascular disease.
authors: Molecular Dynamics Section, National Institute on Aging, National Institutes of Health, Biomedical Research Center, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224-6825, USA. Electronic address: rifkindj@grc.nia.nih.gov.
authors: Joseph M
authors: JM
authors: Rifkind
authors: Molecular Dynamics Section, National Institute on Aging, National Institutes of Health, Biomedical Research Center, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224-6825, USA. Electronic address: nenika1@jhmi.edu.
authors: Enika
authors: E
authors: Nagababu
authors: Department of Kinesiology, Towson University, 8000 York Road, Towson, MD 21252, USA. Electronic address: ddobrosielski@towson.edu.
authors: Devon A
authors: DA
authors: Dobrosielski
authors: Molecular Dynamics Section, National Institute on Aging, National Institutes of Health, Biomedical Research Center, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224-6825, USA. Electronic address: salgadomt@yahoo.com.
authors: Maria T
authors: MT
authors: Salgado
authors: Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Suite 2400, 301 Building, 4940 Eastern Avenue, Baltimore, MD 21224, USA. Electronic address: michaeljdlima@gmail.com.
authors: Michael
authors: M
authors: Lima
authors: Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Suite 2400, 301 Building, 4940 Eastern Avenue, Baltimore, MD 21224, USA. Electronic address: pouyang@jhmi.edu.
authors: Pamela
authors: P
authors: Ouyang
authors: Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Suite 2400, 301 Building, 4940 Eastern Avenue, Baltimore, MD 21224, USA. Electronic address: hsilber@jhmi.edu.
authors: Harry A
authors: HA
authors: Silber
mesh_terms: D000328:Adult; D001132:Arm / Q000098:blood supply*; D005260:Female; D006801:Humans; D048228:Intermittent Pneumatic Compression Devices; D007866:Leg / Q000098:blood supply*; D008297:Male; D009569:Nitric Oxide / Q000097:blood* / Q000378:metabolism; D010865:Pilot Projects; D055815:Young Adult
chemical_list: D009569:Nitric Oxide
keywords: Flow mediated dilation; Intermittent pneumatic compression; Low-flow mediated constriction; Nitric oxide; Nitrite; Occlusion-mediated constriction