Valves in the Heart of the Big Apple VIII: Evaluation and Management of Valvular Heart Diseases 2014. Fifth Annual Joint Scientific Session of the Heart Valve Society of America and Society of Heart Valve Diseases, New York City, N.Y., May 8-10, 2014: Abstracts

OBJECTIVE: Matrix metalloproteinases (MMPs) are endopeptidases involved in extra-cellular matrix remodelling, associated with both physiological and pathological processes of several human tissues and systems, such as vascular system. It is well known their involvement in mediating both beneficial and pathological aorta effects, such as abdominal aorta aneurysms and its complications. On the contrary, unclear data exist about their role in the pathophysiology of sporadic thoracic aorta aneurysm (TAA) and its complications. Thus, the aim of this study was to analyse the role of MMPs in TAA complications, i.e. rupture and dissection. METHODS: Aortic specimens obtained from 73 patients (51 men and 22 women, age 61.7_ 10.7 years) affected by TAAs, 18 patients with type A aortic dissection (TAD) and 30 controls were utilised for histo-pathological and immune-histochemical analyses. In addition, a second control group of 128 subjects (61 men and 67 woman, age 61.1 _ 5.8 years) was enrolled to examine the role of single nucleotide polymorphisms (SNPs) of MMP-9 (NM-004985), MMP-2 (NM-001121363.1) genes in diseases risk. RESULTS: Three different patterns of MMPs (extracellular, intracellular and mixed) with different concentration (low, moderate, elevated) have been observed in case aorta samples. The pattern with elevated MMP amount in aorta samples from TAD cases was also characterised by increased cystic medial degeneration, without substitutive fibrosis, and plurifocal medial apoptosis. In the context of TAA aorta samples, we identified three phenotypes: phenotype I (normal wall); phenotype II (moderate wall thickness); phenotype III (thin and weak wall). In particular TAA phenotype III mainly observed in case samples showed the same histological features of TAD with elevated MMP concentration with a mixed pattern. In addition, significant associations were observed between the 1562C/T MMP-9 and -735C/T MMP-2 SNPs and the risk of both TAA and TAD. CONCLUSIONS: Our data suggest a crucial role of both MMP-2 and MMP-9 in both TAA and its complications, such as TAD. In future they might be considered as new criteria in TAA surgical indications.