Integrity of central nervous autonomous tracts is associated with cardiac function, cardiovascular risk factors, organ damage and major adverse cardiovascular events
Authors: Nolde J , Hosp J A , Weiss J , Rau A , Reisert M 
Published: October 2024

Abstract

Background
Alterations in the central autonomic nervous system have been linked to the pathogenesis of cardiovascular (CV) risk and disease. Moreover, these conditions are treatable by pharmacological or interventional modification of the activity of the autonomic nervous system.

Purpose
The UK Biobank enables the investigation of the relationship between changes in the CAN and CV function or disease within a large population. Microstructural integrity of the CAN was assessed for associations with cardiac function, CV risk and damage representations, and major adverse cardiovascular events (MACE).

Method
Microstructural diffusion metrics for 7 CAN tracts were estimated using a Bayesian approach, which determines the three components of a standard white matter-based tissue model: 1. the free water fraction (CSF); 2. the fraction within neuronal processes, i.e. axons and dendrites (INTRA); and 3. the fraction outside of axons or dendrites (EXTRA), representing the cellular compartment and the extracellular matrix. Volume fractions of the three microstructural components were analysed for associations with cardiac index, blood pressure, CV target organ damage (arterial stiffness, left ventricular mass, and wall thickness), and MACE, using covariate-adjusted regression models that corrected for multiple comparisons.

Results
Analysis of cardiac function in 26,302 participants revealed significant associations between cardiac index and CAN regions in the cortical and subcortical networks. Arterial stiffness was significantly associated with markers of microstructural integrity in the cortical networks only (n=22,491), while systolic (n=34,114) and diastolic blood pressure (n=34,130), left ventricular mass (n=22,491) and wall thickness (n=22,491) showed extensive associations with the cortical and subcortical CAN. MACE (n=33,444) was associated with cortical markers of microstructural integrity of the CAN in limbic pathways (significant CANs all p&lt;0.002) and the CAN pathways connecting cortical areas (significant CANs left all &lt;0.001, right=0.001). The observed pattern of microstructural metrics suggests that the integrity of neural connections (intra-fraction) positively correlates with adverse outcomes, while an increase in free fluid (CSF) volume was typically associated with a negative impact.

Conclusion
In this analysis, markers of CAN integrity and degradation showed extensive associations with indicators of CV function, risk factors, damage parameters, and outcomes. This evidence supports the crucial role of autonomic regulation in cardiovascular disease. Future research is needed to determine whether these associations indicate harmful processes, such as neuroinflammation, contributing to cardiovascular (CV) risk and disease development, or if they are consequences of pre-existing elevated risk factors or events.CANs associated with MACEAssociations of CAN with CV organ damage