Mazor Rafi, Dos Santos Fernando, Li Joyce B, Aletti Federico, Schmid-Schonbein Geert, Kistler Erik B
Department of Anesthesiology and Critical Care, University of California San Diego/VA San Diego Healthcare System, La Jolla, CA.
Department of Bioengineering, University of California San Diego, La Jolla, CA.
Crit Care Explor. 2021 Jul 6;3(7):e0469. doi: 10.1097/CCE.0000000000000469. eCollection 2021 Jul.
Refractory vascular failure due to the inability of vascular smooth muscle to respond to vasoconstrictors such as phenylephrine is a final common pathway for severe circulatory shock of any cause, including trauma/hemorrhagic shock. Increased inflammation, Toll-like receptor 4 activation, and decreased response of the alpha-1 adrenergic receptors which control vascular tone have been reported in trauma/hemorrhagic shock.
In trauma/hemorrhagic shock, Toll-like receptor 4 activation contributes to vascular failure via decreased bioavailability of adrenergic receptors.
Trauma/hemorrhagic shock was induced in Wistar rats (laparotomy combined with mean arterial pressure at 40 mm Hg for 90 min followed by 2 hr resuscitation with Lactated Ringers solution). To inhibit Toll-like receptor 4, resatorvid (TAK-242) and resveratrol were used, and plasma was collected. Smooth muscle cells were incubated with lipopolysaccharide (10 ng/mL) or plasma. Inflammatory cytokines were screened using dot-blot. Toll-like receptor 4 and nuclear factor κB activation and cellular localization of the alpha-1 adrenergic receptor were measured by immunofluorescence imaging and Western blot analysis. Clustered regularly interspaced short palindromic repeats/Cas9 was used to knock out Toll-like receptor 4, and calcium influx following stimulation with phenylephrine was recorded.
Trauma/hemorrhagic shock caused a decreased response to phenylephrine, whereas Toll-like receptor 4 inhibition improved blood pressure. Trauma/hemorrhagic shock plasma activated the Toll-like receptor 4/nuclear factor κB pathway in smooth muscle cells. Double labeling of Toll-like receptor 4 and the alpha-1 adrenergic receptor showed that these receptors are colocalized on the cell membrane. Activation of Toll-like receptor 4 caused cointernalization of both receptors. Calcium influx was impaired in cells incubated with trauma/hemorrhagic shock plasma but restored when Toll-like receptor 4 was knocked out or inhibited.
Activation of the Toll-like receptor 4 desensitizes vascular smooth muscle cells to vasopressors in experimental trauma/hemorrhagic shock by reducing the levels of membrane alpha-1 adrenergic receptor.
由于血管平滑肌无法对去氧肾上腺素等血管收缩剂作出反应而导致的难治性血管衰竭，是包括创伤/失血性休克在内的任何原因引起的严重循环性休克的最终共同途径。据报道，在创伤/失血性休克中，炎症增加、Toll样受体4激活以及控制血管张力的α-1肾上腺素能受体反应性降低。
在创伤/失血性休克中，Toll样受体4激活通过降低肾上腺素能受体的生物利用度导致血管衰竭。
在Wistar大鼠中诱导创伤/失血性休克（剖腹术联合平均动脉压维持在40 mmHg 90分钟，随后用乳酸林格氏液复苏2小时）。为抑制Toll样受体4，使用了瑞斯托维德（TAK-242）和白藜芦醇，并收集血浆。将平滑肌细胞与脂多糖（10 ng/mL）或血浆一起孵育。使用斑点印迹法筛选炎性细胞因子。通过免疫荧光成像和蛋白质印迹分析测量Toll样受体4和核因子κB的激活以及α-1肾上腺素能受体的细胞定位。使用成簇规律间隔短回文重复序列/Cas9敲除Toll样受体4，并记录去氧肾上腺素刺激后的钙内流。
创伤/失血性休克导致对去氧肾上腺素的反应降低，而抑制Toll样受体4可改善血压。创伤/失血性休克血浆激活了平滑肌细胞中的Toll样受体4/核因子κB途径。Toll样受体4和α-1肾上腺素能受体的双重标记显示这些受体共定位于细胞膜上。Toll样受体4的激活导致两种受体共同内化。用创伤/失血性休克血浆孵育的细胞中钙内流受损，但当Toll样受体4被敲除或抑制时恢复。
在实验性创伤/失血性休克中，Toll样受体4的激活通过降低膜α-1肾上腺素能受体水平使血管平滑肌细胞对血管加压药脱敏。
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