TY - JOUR TI - Differential Expression of Collagen Type V and XI α-1 in Human Ascending Thoracic Aortic Aneurysms AU - Toumpoulis, I.K. AU - Oxford, J.T. AU - Cowan, D.B. AU - Anagnostopoulos, C.E. AU - Rokkas, C.K. AU - Chamogeorgakis, T.P. AU - Angouras, D.C. AU - Shemin, R.J. AU - Navab, M. AU - Ericsson, M. AU - Federman, M. AU - Levitsky, S. AU - McCully, J.D. JO - The Annals of Thoracic Surgery PY - 2009 VL - 88 TODO - 2 SP - 506-513 PB - SN - 0003-4975, 1552-6259 TODO - 10.1016/j.athoracsur.2009.04.030 TODO - collagen type 1; collagen type 11; collagen type 3; collagen type 5; fibrillar collagen; messenger RNA, article; ascending aorta; clinical article; controlled study; elective surgery; electron microscopy; extracellular matrix; gene expression; gene mutation; histopathology; human; human tissue; immunofluorescence test; priority journal; protein blood level; quantitative analysis; real time polymerase chain reaction; reverse transcription polymerase chain reaction; thoracic aorta aneurysm; tissue section; Western blotting, Aortic Aneurysm, Thoracic; Collagen Type V; Collagen Type XI; Disease Progression; Extracellular Matrix; Humans; Immunohistochemistry; Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger TODO - Background: The molecular mechanisms leading to ascending thoracic aortic aneurysms (ATAAs) remain unknown. We hypothesized that alterations in expression levels of specific fibrillar collagens occur during the aneurysmal process. Methods: Surgical samples from ascending aortas from patients with degenerative ATAAs were subdivided by aneurysm diameter: small, 5 to 6 cm; medium, 6 to 7 cm; and large, greater than 7 cm; and compared with nonaneurysmal aortas (mean diameter, 2.3 cm). Results: Histology, immunofluorescence, and electron microscopy demonstrated greater disorganization of extracellular matrix constituents in ATAAs as compared with control with an increase in collagen α1(XI) within regions of cystic medial degenerative lesions. Real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) showed collagens type V and α1(XI) were significantly and linearly increased in ATAAs as compared with control (p < 0.001). There was no change in the messenger ribonucleic acid (mRNA) expression levels of collagens type I and III. Western blot analysis showed collagens type I and III were significantly decreased and collagens α1(XI) and V were significantly increased and were linearly correlated with the size of the aneurysm (p < 0.001 for both). Conclusions: These results demonstrate that increased collagen α1(XI) and collagen V mRNA and protein levels are linearly correlated with the size of the aneurysm and provide a potential mechanism for the generation and progression of aneurysmal enlargement. © 2009 The Society of Thoracic Surgeons. ER -