Development of Bionic Baroreflex System for Treatment of Orthostatic Hypotension due to Shy-Drager Syndrome

背景：我们开发了一种治疗压力感受性反射衰竭的仿生技术，并测试了其对压力感受性反射衰竭大鼠动脉压的恢复效果。方法和结果：仿生压力反射系统(BBS)是一个由计算机控制的负反馈系统，人工血管运动中心。它通过放置在主动脉弓内的微型压力计感知全身动脉压(SAP)，并自动计算刺激交感传出神经的脉冲串的频率。由于内脏大神经支配的腹部血管床是压力感受性反射控制动脉压的主要效应机制，因此我们选择腹神经节作为BBS的交感血管运动界面。为了使这个系统仿生，人工血管运动中枢(H&lt；BRp→)的运行规则与自然中枢的运行规则被积极地匹配。首先，我们确定了SAP的自然压力感受性反射控制的开环传递函数(H&lt；Native&gt；)以及SAP对电刺激腹腔神经节的反应(H&lt；STM→SAP&>t；)。我们从H&lt；Native&>/H_&&lt；STM→→&>计算出H&lt；BRP；STM&>，并将运算规则移植到计算机中。在10只压力感受性反射衰竭大鼠中，我们评估了BBS在HUT快速降压时的表现。突然的直立倾斜使SAP在2秒内下降了34±6 mm Hg，在10秒内下降了52±5 mm Hg。另一方面，在实时执行BBS时，SAP在HUT后2秒下降21±5 mm Hg，在HUT后10 s下降15±6 mm Hg。结论：BBS可恢复压力感受性反射衰竭大鼠的自主压力感受性反射功能。

Background : We developed a bionic technology for the treatment of baroreflex failure, and tested its efficacy in restoration of arterial pressure against head-up tilt (HUT) in rats with baroreflex failure.Methods and Results : The bionic baroreflex system (BBS) was a negative feedback system controlled by a computer, the artificial vasomotor center. It sensed systemic arterial pressure (SAP) through a micromanometer placed in the aortic arch and automatically computed the frequency of a pulse train to stimulate sympathetic efferent nerves. We selected the celiac ganglion as the sympathetic vasomotor interface for the BBS, because the abdominal vascular bed innervated by the greater splanchnic nerve is a major effector mechanism for the baroreflex control of arterial pressure. To make this system to be BIONIC, the operational rule of the artificial vasomotor center (H_<BRP→STM>) was actively matched to that of the native center. First, we identified the open-loop transfer functions of the native baroreflex control of SAP (H_<Native>) and the response of SAP to electrical stimulation of the celiac ganglion (H_<STM→SAP>). We computed H_<BRP→STM> from H_<Native>/H_<STM→SAP>, and transplanted the operational rule into the computer. In 10 rats with baroreflex failure, we evaluated the performance of the BBS during rapid hypotension induced by HUT. Abrupt head-up tilting dropped SAP by 34±6 mmHg in 2 sec, and by 52±5 mmHg in 10 sec. During real-time execution of the BBS, on the other hand, the fall in SAP was 21±5 mmHg at 2 sec, and 15±6 mmHg at 10 sec after HUT. These arterial responses controlled by the BBS were indistinguishable from those by the native baroreflex.Conclusions : We concluded that the BBS revitalized the native baroreflex function in rats with baroreflex failure.