Resetting blood pressure by a closed-loop implanted chip system in normotensive rats

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Neuroscience

Background:

• Hypertension is a significant global health concern.
• Current treatments often rely on pharmaceuticals with potential side effects.
• Need for innovative, non-pharmacological blood pressure management strategies.

Purpose of the Study:

• To develop and evaluate a closed-loop implanted chip system for drug-free blood pressure control.
• To investigate the mechanism of blood pressure regulation mediated by the chip system.
• To assess the independence of the hypotensive effect from bradycardia.

Main Methods:

• Design of a closed-loop implanted chip system for real-time blood pressure monitoring and nerve stimulation.
• In vitro and in vivo characterization of the pressure-stimulation frequency relationship.
• Evaluation of the chip system's efficacy in anesthetized Wistar rats.
• Pharmacological assessment using methyl atropine and vagotomy to elucidate the role of bradycardia.

Main Results:

• The chip system demonstrated a linear relationship between blood pressure and stimulation frequency (70-160 mm Hg).
• Stimulation reached maximum frequency (100 Hz) above 160 mm Hg and ceased below 70 mm Hg.
• Significant reductions in mean arterial pressure (-20.0+/-4.4 mm Hg) and heart rate (-43.0+/-10.5 bpm) were observed, with rapid recovery.
• Bradycardia was abolished by methyl atropine or vagotomy, but the hypotensive effect remained significant.

Conclusions:

• The closed-loop implanted chip system effectively resets blood pressure in rats.
• The observed hypotension is primarily independent of the bradycardia response.
• This technology presents a promising avenue for non-pharmacological hypertension management.