scholarly journals Impact of shear rate pattern on upper and lower limb conduit artery endothelial function in both spinal cord-injured and able-bodied men

2015 ◽  
Vol 100 (10) ◽  
pp. 1107-1117 ◽  
Author(s):  
J. O. Totosy de Zepetnek ◽  
D. S. Ditor ◽  
J. S. Au ◽  
M. J. MacDonald
Keyword(s):  
Spinal Cord ◽  
Shear Rate ◽  
Endothelial Function ◽  
Lower Limb ◽  
Conduit Artery ◽  
Spinal Cord Injured

Preserved flow-mediated dilation in the inactive legs of spinal cord-injured individuals

2004 ◽  
Vol 287 (1) ◽  
pp. H374-H380 ◽  
Author(s):  
Patricia C. E. de Groot ◽  
Fleur Poelkens ◽  
Miriam Kooijman ◽  
Maria T. E. Hopman
Keyword(s):  
Spinal Cord ◽  
Shear Rate ◽  
Endothelial Function ◽  
Femoral Artery ◽  
Brachial Artery ◽  
Rate Ratio ◽  
Arterial Occlusion ◽  
Flow Mediated Dilation ◽  
Dilatory Response ◽  
Spinal Cord Injured

The aim of the study was to assess endothelial function, measured by flow-mediated dilation (FMD), in an inactive extremity (leg) and chronically active extremity (arm) within one subject. Eleven male spinal cord-injured (SCI) individuals and eleven male controls (C) were included. Echo Doppler measurements were performed to measure FMD responses after 10 and 5 min of arterial occlusion of the leg (superficial femoral artery, SFA) and the arm (brachial artery, BA), respectively. A nitroglycerine spray was administered to determine the endothelium independent vasodilatation in the SFA. In the SFA, relative changes in FMD were significantly enhanced in SCI compared with C (SCI: 14.1 ± 1.3%; C: 9.2 ± 2.3%), whereas no differences were found in the BA (SCI: 12.5 ± 2.9%; C: 14.2 ± 3.3%). Because the FMD response is directly proportional to the magnitude of the stimulus, the FMD response was also expressed relative to the shear rate. No differences between the groups were found for the FMD-to-shear rate ratio in the SFA (SCI:0.061 ± 0.023%/s−1; C: 0.049 ± 0.024%/s−1), whereas the FMD-to-shear rate ratio was significantly decreased in the BA of SCI individuals (SCI: 0.037 ± 0.01%/s−1; C: 0.061 ± 0.027%/s−1). The relative dilatory response to nitroglycerine did not differ between the groups. (SCI: 15.6 ± 2.0%; C: 13.4 ± 2.3%). In conclusion, our results indicate that SCI individuals have a preserved endothelial function in the inactive legs and possibly an attenuated endothelial function in the active arms compared with controls.

scholarly journals Lower limb conduit artery endothelial responses to acute upper limb exercise in spinal cord injured and able-bodied men

2015 ◽  
Vol 3 (4) ◽  
pp. e12367 ◽  
Author(s):  
Julia O. Totosy de Zepetnek ◽  
Jason S. Au ◽  
David S. Ditor ◽  
Maureen J. MacDonald
Keyword(s):  
Spinal Cord ◽  
Upper Limb ◽  
Lower Limb ◽  
Conduit Artery ◽  
Spinal Cord Injured ◽  
Limb Exercise

scholarly journals Lower limb fractures in the chronic spinal cord injured patient

Spinal Cord ◽  
1989 ◽  
Vol 27 (2) ◽  
pp. 133-139 ◽  
Author(s):  
R R Ingram ◽  
R K Suman ◽  
P A Freeman
Keyword(s):  
Spinal Cord ◽  
Lower Limb ◽  
Injured Patient ◽  
Spinal Cord Injured Patient ◽  
Lower Limb Fractures ◽  
Limb Fractures ◽  
Spinal Cord Injured

scholarly journals Muscle perfusion of posterior trunk and lower-limb muscles at rest and during upper-limb exercise in spinal cord-injured and able-bodied individuals

Spinal Cord ◽  
2012 ◽  
Vol 50 (11) ◽  
pp. 822-826 ◽  
Author(s):  
A Zafeiridis ◽  
A V Vasiliadis ◽  
A Doumas ◽  
N Galanis ◽  
T Christoforidis ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Upper Limb ◽  
Lower Limb ◽  
Muscle Perfusion ◽  
Lower Limb Muscles ◽  
Limb Muscles ◽  
Posterior Trunk ◽  
Spinal Cord Injured ◽  
Limb Exercise

scholarly journals UBC-Nepal expedition: upper and lower limb conduit artery shear stress and flow-mediated dilation on ascent to 5,050 m in lowlanders and Sherpa

2018 ◽  
Vol 315 (6) ◽  
pp. H1532-H1543 ◽  
Author(s):  
Joshua C. Tremblay ◽  
Ryan L. Hoiland ◽  
Howard H. Carter ◽  
Connor A. Howe ◽  
Mike Stembridge ◽  
...  
Keyword(s):  
Shear Stress ◽  
Endothelial Function ◽  
High Altitude ◽  
Blood Viscosity ◽  
Lower Limb ◽  
Adaptation To Hypoxia ◽  
Flow Mediated Dilation ◽  
Conduit Artery ◽  
Arterial Blood ◽  
Retrograde Shear

The study of conduit artery endothelial adaptation to hypoxia has been restricted to the brachial artery, and comparisons with highlanders have been confounded by differences in altitude exposure, exercise, and unknown levels of blood viscosity. To address these gaps, we tested the hypothesis that lowlanders, but not Sherpa, would demonstrate decreased mean shear stress and increased retrograde shear stress and subsequently reduced flow-mediated dilation (FMD) in the upper and lower limb conduit arteries on ascent to 5,050 m. Healthy lowlanders (means ± SD, n = 22, 28 ± 6 yr) and Sherpa ( n = 12, 34 ± 11 yr) ascended over 10 days, with measurements taken on nontrekking days at 1,400 m (baseline), 3,440 m ( day 4), 4,371 m ( day 7), and 5,050 m ( day 10). Arterial blood gases, blood viscosity, shear stress, and FMD [duplex ultrasound of the brachial and superficial femoral arteries (BA and SFA, respectively)] were acquired at each time point. Ascent decreased mean and increased retrograde shear stress in the upper and lower limb of lowlanders and Sherpa. Although BA FMD decreased in lowlanders from 7.1 ± 3.9% to 3.8 ± 2.8% at 5,050 versus 1,400 m ( P < 0.001), SFA FMD was preserved. In Sherpa, neither BA nor SFA FMD were changed upon ascent to 5,050 m. In lowlanders, the ascent-related exercise may favorably influence endothelial function in the active limb (SFA); selective impairment in FMD in the BA in lowlanders is likely mediated via the low mean or high oscillatory baseline shear stress. In contrast, Sherpa presented protected endothelial function, suggesting a potential vascular aspect of high-altitude acclimatization/adaptation. NEW & NOTEWORTHY Upper and lower limb arterial shear stress and flow-mediated dilation (FMD) were assessed on matched ascent from 1,400 to 5,050 m in lowlanders and Sherpa. A shear stress pattern associated with vascular dysfunction/risk manifested in both limbs of lowlanders and Sherpa. FMD was impaired only in the upper limb of lowlanders. The findings indicate a limb-specific impact of high-altitude trekking on FMD and a vascular basis to acclimatization wherein endothelial function is protected in Sherpa on ascent

Impact of acute exposure to increased hydrostatic pressure and reduced shear rate on conduit artery endothelial function: a limb-specific response

2009 ◽  
Vol 297 (3) ◽  
pp. H1103-H1108 ◽  
Author(s):  
Jaume Padilla ◽  
Ryan D. Sheldon ◽  
Diana M. Sitar ◽  
Sean C. Newcomer
Keyword(s):  
Hydrostatic Pressure ◽  
Shear Rate ◽  
Endothelial Function ◽  
Pressure Gradient ◽  
Brachial Artery ◽  
Popliteal Artery ◽  
Lower Limbs ◽  
Acute Exposure ◽  
Specific Response ◽  
Conduit Artery

Unlike quadrupeds, humans exhibit a larger hydrostatic pressure in the lower limbs compared with the upper limbs during a major part of the day. It is plausible that repeated episodes of elevated pressure in the legs may negatively impact the endothelium, hence contributing to the greater predisposition of atherosclerosis in the legs. We tested the hypothesis that an acute exposure to increased hydrostatic pressure would induce conduit artery endothelial dysfunction. In protocol 1, to mimic the hemodynamic environment of the leg, we subjected the brachial artery to a hydrostatic pressure gradient (∼15 mmHg) by vertically hanging the arm for 3 h. Brachial artery flow-mediated dilation (FMD) was assessed in both arms before and following the intervention. In protocol 2, we directly evaluated popliteal artery FMD before and after a 3-h upright sitting (pressure gradient ∼48 mmHg) and control (supine position) intervention. Our arm-hanging model effectively resembled the hemodynamic milieu (high pressure and low shear rate) present in the lower limbs during the seated position. Endothelium-dependent vasodilation at the brachial artery was attenuated following arm hanging ( P < 0.05); however, contrary to our hypothesis, upright sitting did not have an impact on popliteal artery endothelial function ( P > 0.05). These data suggest an intriguing vascular-specific response to increased hydrostatic pressure and reduced shear rate. Further efforts are needed to determine if this apparent protection of the leg vasculature against an acute hydrostatic challenge is attributable to posture-induced chronic adaptations.

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