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

Abstract

Study design: Nonrandomized-controlled trial. Objectives: To assess muscle perfusion at rest and during arm-cranking exercise (ACE) in upper and lower posterior trunk and vastus lateralis (VL) muscles in individuals with spinal cord injury (SCI) and controls (C). Setting: Exercise Physiology-Biochemistry Laboratory. Methods: Eight SCI with thoracic lesion and eight C received injections of radioactive tracer to trapezius (TRAP), latissimus dorsi (LAT) and VL. Radioactive counts were recorded with a g-camera for 10 min at rest and during ACE (60% VO 2max for 20 min). Timecount curves were generated and the isotope clearance rate, expressed as half-life time (T 1/2 ,min), was calculated to assess muscle perfusion. Results: Resting T 1/2 was lower in TRAP and LAT vs VL (Po0.05) in SCI, however, there were no differences among muscles in C. Arm-cranking increased (Po0.001) the isotope clearance in TRAP and LAT in SCI and C, whereas no effect was found on T 1/2 in VL in both groups. T 1/2 was longer (Po0.05) in SCI vs C in VL at rest and during ACE, whereas there were no differences between groups in posterior trunk muscles. Conclusions: Resting muscle perfusion was reduced in the paralyzed limbs of SCI compared with C, whereas there was no evidence of impaired microcirculation in upper and lower back muscles in SCI. Although ACE did not induce a hyperemic response in VL, it increased hyperemia in upper and lower posterior trunk muscles in SCI, suggesting beneficial effects of this type of activity on muscle microvasculature in this region.

The Vascular Side of Chronic Bed Rest: When a Therapeutic Approach Becomes Deleterious

“…Demiot et al [13] revealed a significant reduction in resting cutaneous microcirculation, measured by means of laser Doppler, after 56 days of bed rest in sedentary individuals. Furthermore, Zafeiridis et al [28] measured resting muscle perfusion and capillary flow in vastus lateralis muscle of spinal cord-injured and able-bodied individuals by means of local clearance of a radioactive tracer ( 99m Tc-pertechnetate). Results showed that microcirculation in paralyzed subjects was reduced by~40% compared with that in able-bodied subjects [28].…”

“…Furthermore, Zafeiridis et al [28] measured resting muscle perfusion and capillary flow in vastus lateralis muscle of spinal cord-injured and able-bodied individuals by means of local clearance of a radioactive tracer ( 99m Tc-pertechnetate). Results showed that microcirculation in paralyzed subjects was reduced by~40% compared with that in able-bodied subjects [28]. Again, although the methods and the subjects included in the previous studies are different from ours, the results are in line with our findings.…”

Cutaneous microvascular perfusion responses to insulin iontophoresis are differentially affected by insulin resistance after spinal cord injury

“…; Zafeiridis et al . ), an important mechanism to promote positive endothelial adaptations to exercise, but there is still insufficient evidence for exercise intervention to result in improved cutaneous perfusion through augmented endothelial function. Lifestyle modifications have been found to improve local vasodilatory responses to insulin iontophoresis among individuals with the metabolic syndrome (Vinet et al .…”

“…There is general agreement that beneficial adaptations to training conditions can lead to improvements in sublesional macrovascular endothelial function, whether or not increases in lean tissue mass occur in parallel (Olive et al 2003;de Groot et al 2005;Thijssen et al 2005;Totosy de Zepetnek et al 2015b). Likewise, there is evidence for improved cutaneous and muscle microvascular perfusion responses to acute bouts of exercise in persons SCI (Muraki et al 1995(Muraki et al , 1996Theisen et al 2001;Van Duijnhoven et al 2009;Zafeiridis et al 2012), an important mechanism to promote positive endothelial adaptations to exercise, but there is still insufficient evidence for exercise intervention to result in improved cutaneous perfusion through augmented endothelial function. Lifestyle modifications have been found to improve local vasodilatory responses to insulin iontophoresis among individuals with the metabolic syndrome (Vinet et al 2015), but the same has yet to be demonstrated in persons with SCI.…”

Circulating angiogenic biomolecules at rest and in response to upper-limb exercise in individuals with spinal cord injury

“…interleukins-6 and blood flow to the exercising muscles). 49,50 This study has some potential limitations. First, our findings are limited to individuals with complete thoracic lesions.…”