The Role of the Autonomic Nervous System in Atherosclerosis of the Thoracic Aorta: A Cadaveric Study

Objective: The Autonomic Nervous System (ANS) has been associated with numerous atherosclerosis-inducedcardiovascular events, such as myocardial infarction and aortic disease. Although evidence suggests a relationshipbetween autonomic dysfunction and atherosclerotic disease, the underlying mechanisms are still underinvestigation. The purpose of this study is to investigate the effect of ANS to the development of atherosclerosis andvice versa, in human thoracic aorta.Methods: An autopsy analysis from three segments of the thoracic aorta was performed; ascending aorta, aorticarch, descending aorta, using 52 unselected adult cadavers (38 male, 14 female-mean age 64.4 years; age range19-90 years). Subjects were divided in two age groups ( 65 years-n=26). Tissue specimens weremacroscopically examined and histopathologically divided into 7 grades of scoring for atherosclerosis (ATHERO,from 0=intact, to 6=thrombi formation). The relationship between ANS and atherosclerosis was depicted by furtherimmunohistochemical analysis for detection of neuron terminals onto the aortic wall. All data were evaluatedaccording to the subject’s demographic and clinical characteristics.Results: Total 96.2% of all subjects had atherosclerosis of variable degree in one or more segments. Noaneurismal change was found. The presence of atheromas were common in all subjects regardless of age andsegment, with atherosclerosis increasing by age; Ascending aorta (r=.571, p 65 years (r=.450, p=.023). In addition, a positive history of hypertension was statistically significant regardingboth the presence of atherosclerosis and neuron terminals in all three aortic wall segments; Ascending aorta (p=.037), Aortic arch (p=.046), Descending aorta (p=.045). Furthermore, there was a strong negative correlationbetween the ATHERO score and the presence of neuron terminals in all three aortic segments; Ascending aorta(r=-.264, p=.041), Aortic arch (r=-.400, p=.003), Descending aorta (r=-.234, p=.047).Conclusion: Human cadaveric studies are extremely useful in understanding the pathophysiology of ANS, alongwith clinical and animal studies that are most commonly performed. These data suggest that there is a link betweenautonomic disfunction and the presence of atherosclerosis in human thoracic aorta, especially when hypertension ispresent. It is therefore possible that stress-induced hypertension can be considered as a potential risk factor for thedevelopment of atherosclerosis.