Oxidative stress in genetically triggered thoracic aortic aneurysm: role in pathogenesis and therapeutic opportunities

Background: The primary objective of this review was to explore the contribution of oxidative stress to the pathogenesis of genetically-triggered thoracic aortic aneurysm (TAA). Genetically-triggered TAAs manifest substantial variability in onset, progression, and risk of aortic dissection, posing a significant clinical management challenge. There is a need for non-invasive biomarkers that predict the natural course of TAA and therapeutics that prevent aneurysm progression.

Methods: An online systematic search was conducted within PubMed, MEDLINE, Scopus and ScienceDirect databases using keywords including: oxidative stress, ROS, nitrosative stress, genetically triggered thoracic aortic aneurysm, aortic dilatation, aortic dissection, Marfan syndrome, Bicuspid Aortic Valve, familial TAAD, Loeys Dietz syndrome, and Ehlers Danlos syndrome.

Results: There is extensive evidence of oxidative stress and ROS imbalance in genetically triggered TAA. Sources of ROS imbalance are variable but include dysregulation of redox mediators leading to either insufficient ROS removal or increased ROS production. Therapeutic exploitation of redox mediators is being explored in other cardiovascular conditions, with potential application to TAA warranting further investigation.

Conclusion: Oxidative stress occurs in genetically triggered TAA, but the precise contribution of ROS to pathogenesis remains incompletely understood. Further research is required to define causative pathological relationships in order to develop therapeutic options.

The Role of Inflammation and Myeloperoxidase-Related Oxidative Stress in the Pathogenesis of Genetically Triggered Thoracic Aortic Aneurysms

Genetically triggered thoracic aortic aneurysms (TAAs) are usually considered to exhibit minimal levels of inflammation. However, emerging data demonstrate that specific features of an inflammatory response can be observed in TAA, and that the extent of the inflammatory response can be correlated with the severity, in both mouse models and in human studies. Myeloperoxidase (MPO) is a key mediator of the inflammatory response, via production of specific oxidative species, e.g., the hypohalous acids. Specific tissue modifications, mediated by hypohalous acids, have been documented in multiple cardiovascular pathologies, including atherosclerosis associated with coronary artery disease, abdominal aortic, and cerebral aneurysms. Similarly, data are now emerging that show the capacity of MPO-derived oxidative species to regulate mechanisms important in TAA pathogenesis, including alterations in extracellular matrix homeostasis, activation of matrix metalloproteinases, induction of endothelial dysfunction and vascular smooth muscle cell phenotypic switching, and activation of ERK1/2 signaling. The weight of evidence supports a role for inflammation in exacerbating the severity of TAA progression, expanding our understanding of the pathogenesis of TAA, identifying potential biomarkers for early detection of TAA, monitoring severity and progression, and for defining potential novel therapeutic targets.