Bionic Baroreceptor Corrects Postural Hypotension in Rats with Impaired Baroreceptor
Background—Impairment of the arterial baroreflex causes orthostatic hypotension (OH). The arterial baroreceptor sensitivity degrades with age. Thus impaired baroreceptor plays a pivotal role in OH in most elderly patients. There is no effective treatment for OH. The aims of this investigation were to develop a bionic baroreceptor (BBR) and to verify whether it corrects postural hypotension.
Methods and Results—The BBR consists of a pressure sensor, a regulator and a neuro-stimulator. In 35 Sprague-Dawley rats, we vascularily and neurally isolated the baroreceptor regions, and attached electrodes to the aortic depressor nerve for stimulation (STM). To mimic impaired baroreceptors, we maintained the intra-carotid sinus pressure (CSP) at 60 mmHg during activation of the BBR. Native baroreflex was reproduced by matching CSP to the instantaneous pulsatile aortic pressure. The encoding rule for translating CSP into STM was identified by white noise technique and applied to the regulator. The open-loop arterial pressure (AP) response to CSP (n = 7) and upright tilt-induced changes in AP (n = 7) were compared between native baroreceptor and the BBR conditions. The CSP-AP relationships were comparable. Compared with the absence of baroreflex, the BBR corrected tilt-induced hypotension as effectively as under native baroreceptor condition (native: -39 ± 5 mmHg, BBR: -41 ± 5 mmHg, absence: -63 ± 5 mmHg, p < 0.05).
Conclusions—The BBR restores the pressure buffering function. Although this research demonstrated feasibility of the BBR, further research is needed to verify the long term effect and safety in larger animal models and humans.
- blood pressure
- electrical stimulation
- hypotension (low blood pressure)
- nervous system, autonomic
- Received March 28, 2012.
- Accepted July 13, 2012.
- Copyright © 2012, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited