Sympathetic hyperactivity and aortic sympathetic nerve sprouting in patients with thoracic aortic dissection

Area of Science:

• Cardiovascular Research
• Neuroscience
• Medical Physiology

Background:

• The relationship between thoracic aortic dissection (TAD) and sympathetic nervous system (SNS) activity remains largely unknown.
• Investigating this connection is crucial for understanding TAD pathophysiology.

Purpose of the Study:

• To elucidate the relationship between thoracic aortic dissection (TAD) and sympathetic nervous system (SNS) activity.
• To compare SNS markers in TAD patients versus a control group.

Main Methods:

• Measurements included electrocardiography, blood pressure, respiratory activity, and muscle sympathetic nerve activity (MSNA).
• Assessed plasma norepinephrine levels and nerve fiber densities (tyrosine hydroxylase and growth-associated protein 43).
• Statistical analysis was performed on all detected variables.

Main Results:

• TAD patients exhibited significantly lower R-R interval variance and higher blood pressure, heart rate, and respiratory rate compared to controls.
• Elevated muscle sympathetic nerve activity (MSNA) and plasma norepinephrine indicated heightened sympathetic nervous system (SNS) activity in TAD patients.
• Increased tyrosine hydroxylase and growth-associated protein 43-positive nerve fiber density suggested sympathetic sprouting and innervation in TAD.

Conclusions:

• Thoracic aortic dissection (TAD) is associated with elevated sympathetic nervous system (SNS) activity.
• Both systemic and regional aortic SNS activity appear to be increased in TAD patients.