Is there an immunogenomic difference between thoracic and abdominal aortic aneurysms?

Area of Science:

• Cardiovascular Research
• Genetics and Immunology

Background:

• Aortic aneurysms, particularly abdominal aortic aneurysms (AAA) and thoracic aortic aneurysms (TAA), pose significant health risks due to potential dissection or rupture.
• AAA is more prevalent than TAA, with TAA often underdiagnosed due to lack of screening.
• Understanding the natural history, genetic factors, and immunological differences is crucial for effective management and improved survival rates.

Purpose of the Study:

• To conduct a comprehensive literature review on the natural history, immunology, and genetic distinctions between AAAs and TAAs.
• To compare the expansion rates and pathogenetic mechanisms of AAAs and TAAs.

Main Methods:

• Systematic literature search conducted across OVID, SCOPUS, and PubMed databases.
• Review and synthesis of existing research on aortic aneurysm natural history, genetics, and immunology.

Main Results:

• Abdominal aortic aneurysms (AAA) exhibit a faster expansion rate (0.3-0.45 cm/year) compared to thoracic aortic aneurysms (TAA) (up to 0.3 cm/year).
• Degradation of the aortic extracellular matrix by Matrix metalloproteinases (MMPs) is a key factor in AAA pathogenesis.
• Overactive Transforming growth factor-beta (TGF-β) signaling is a major contributor to TAA pathogenesis.

Conclusions:

• Differences in pathogenetic mechanisms, including MMPs in AAA and TGF-β in TAA, highlight distinct biological pathways.
• Future genetic testing holds promise for identifying individuals predisposed to developing either AAA or TAA, enabling earlier detection and intervention.