The effect of a spinal cord injury (SCI) on vascular function has been clouded by both the physiological and mathematical bias of assessing vasodilation in arteries with differing diameters both above and below the lesion and when comparing with healthy, non-disabled controls (CTRL). Thus, we measured vascular function, with flow mediated vasodilation (FMD), in 10 SCI and 10 CTRL with all arteries matched for diameter (≈0.5cm): brachial (BA, arm, functional-limb in both groups) and popliteal artery (PA, leg, disused-limb in SCI, functional-limb in CTRL). PA %FMD was significantly attenuated in SCI (5.6±0.6%) compared to CTRL (8.4±1.3%), with no difference in the BA (SCI: 8.6±0.9%; CTRL: 8.7±0.7%). However, unlike the arm, where muscle mass was preserved, the legs of the SCI were significantly smaller than CTRL (~70%). Thus, reactive hyperemia (RH), which is heavily dependent upon the volume of muscle occluded, in the PA was attenuated in the SCI (144±22ml) compared to CTRL (258±16ml), but not different in the BA. Consequently, shear rate was significantly diminished in the PA of the SCI, such that %FMD/shear rate (vascular responsiveness) was actually greater in the SCI (1.5±0.1%・s^-1) than CTRL (1.2±0.1%・s^-1). Of note, this was significantly greater than both their own BA (0.9±0.1%・s^-1) and that of the CTRL (0.9±0.1%・s^-1). Therefore, examining vessels of similar size, this study reveals normal vascular function above the lesion and vascular dysfunction below the lesion. However, below the lesion there was, actually, evidence of increased vascular responsiveness in this population.

中文翻译：

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脊髓损伤和血管功能：来自直径匹配血管的证据

脊髓损伤 (SCI) 对血管功能的影响因评估病变上方和下方不同直径的动脉血管舒张以及与健康、非残疾对照 (CTRL) 进行比较时的生理和数学偏差而变得模糊。 。因此，我们在 10 次 SCI 和 10 次 CTRL 中通过血流介导的血管舒张 (FMD) 测量了血管功能，所有动脉的直径均匹配 (≈0.5cm)：肱动脉（两组中的 BA、手臂、功能肢）和腘动脉（ PA，腿，SCI 中的废弃肢体，CTRL 中的功能肢体）。与 CTRL (8.4±1.3%) 相比，SCI 中的 PA %FMD 显着减弱 (5.6±0.6%)，而 BA 中没有差异 (SCI：8.6±0.9%；CTRL：8.7±0.7%)。然而，与保留肌肉质量的手臂不同，SCI 的腿部明显小于 CTRL（约 70%）。因此，与 CTRL (258±16ml) 相比，PA 中的反应性充血 (RH) 在很大程度上取决于闭塞肌肉的体积，在 SCI (144±22ml) 中减弱，但在 BA 中没有不同。因此，SCI 的 PA 中的剪切率显着降低，因此 SCI 中的 %FMD/剪切率（血管反应性）实际上 (1.5±0.1%·s -1 ) 比 CTRL (1.2±0.1%·s ⁾更大^-1）。值得注意的是，这明显高于他们自己的 BA (0.9±0.1%·s ^-1 ) 和 CTRL (0.9±0.1%·s ^-1 )。因此，通过检查相似大小的血管，本研究揭示了病变上方的正常血管功能和病变下方的血管功能障碍。然而，实际上，在病变下方有证据表明该人群的血管反应性增加。