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Pierce DM, Maier F, Weisbecker H, Viertler C, Verbrugghe P, Famaey N, Fourneau I, Herijgers P, Holzapfel GA. Human thoracic and abdominal aortic aneurysmal tissues: Damage experiments, statistical analysis and constitutive modeling. J Mech Behav Biomed Mater 2014; 41:92-107. [PMID: 25460406 DOI: 10.1016/j.jmbbm.2014.10.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 09/26/2014] [Accepted: 10/06/2014] [Indexed: 12/31/2022]
Abstract
Development of aortic aneurysms includes significant morphological changes within the tissue: collagen content increases, elastin content reduces and smooth muscle cells degenerate. We seek to quantify the impact of these changes on the passive mechanical response of aneurysms in the supra-physiological loading range via mechanical testing and constitutive modeling. We perform uniaxial extension tests on circumferentially and axially oriented strips from five thoracic (65.6 years ± 13.4, mean ± SD) and eight abdominal (63.9 years ± 11.4) aortic fusiform aneurysms to investigate both continuous and discontinuous softening during supra-physiological loading. We determine the significance of the differences between the fitted model parameters: diseased thoracic versus abdominal tissues, and healthy (Weisbecker et al., J. Mech. Behav. Biomed. Mater. 12, 93-106, 2012) versus diseased tissues. We also test correlations among these parameters and age, Body Mass Index (BMI) and preoperative aneurysm diameter, and investigate histological cuts. Tissue response is anisotropic for all tests and the anisotropic pseudo-elastic damage model fits the data well for both primary loading and discontinuous softening which we interpret as damage. We found statistically relevant differences between model parameters fitted to diseased thoracic versus abdominal tissues, as well as between those fitted to healthy versus diseased tissues. Only BMI correlated with fitted model parameters in abdominal aortic aneurysmal tissues.
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Affiliation(s)
- David M Pierce
- Departments of Mechanical Engineering, Biomedical Engineering and Mathematics, University of Connecticut, CT, USA
| | - Franz Maier
- Institute of Biomechanics, Graz University of Technology, Graz, Austria
| | - Hannah Weisbecker
- Institute of Biomechanics, Graz University of Technology, Graz, Austria
| | | | - Peter Verbrugghe
- Experimental Cardiac Surgery, Faculty of Medicine, UZ Leuven, Leuven, Belgium
| | - Nele Famaey
- Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Inge Fourneau
- Vascular Surgery, Faculty of Medicine, UZ Leuven, Leuven, Belgium
| | - Paul Herijgers
- Experimental Cardiac Surgery, Faculty of Medicine, UZ Leuven, Leuven, Belgium
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Etminan N, Dreier R, Buchholz BA, Beseoglu K, Bruckner P, Matzenauer C, Torner JC, Brown RD, Steiger HJ, Hänggi D, Macdonald RL. Age of collagen in intracranial saccular aneurysms. Stroke 2014; 45:1757-63. [PMID: 24781080 DOI: 10.1161/strokeaha.114.005461] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE The chronological development and natural history of cerebral aneurysms (CAs) remain incompletely understood. We used (14)C birth dating of a main constituent of CAs, that is, collagen type I, as an indicator for biosynthesis and turnover of collagen in CAs in relation to human cerebral arteries to investigate this further. METHODS Forty-six ruptured and unruptured CA samples from 43 patients and 10 cadaveric human cerebral arteries were obtained. The age of collagen, extracted and purified from excised CAs, was estimated using (14)C birth dating and correlated with CA and patient characteristics, including the history of risk factors associated with atherosclerosis and potentially aneurysm growth and rupture. RESULTS Nearly all CA samples contained collagen type I, which was <5 years old, irrespective of patient age, aneurysm size, morphology, or rupture status. However, CAs from patients with a history of risk factors (smoking or hypertension) contained significantly younger collagen than CAs from patients with no risk factors (mean, 1.6±1.2 versus 3.9±3.3 years, respectively; P=0.012). CAs and cerebral arteries did not share a dominant structural protein, such as collagen type I, which would allow comparison of their collagen turnover. CONCLUSIONS The abundant amount of relatively young collagen type I in CAs suggests that there is an ongoing collagen remodeling in aneurysms, which is significantly more rapid in patients with risk factors. These findings challenge the concept that CAs are present for decades and that they undergo only sporadic episodes of structural change.
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Affiliation(s)
- Nima Etminan
- From the Department of Neurosurgery (N.E., K.B., H.-J.S., D.H.) and Institute of Forensic Medicine (C.M.), Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany; Institute for Physiological Chemistry and Pathobiochemistry, Westfalian Wilhelms-University, Münster, Germany (R.D., P.B.); Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, CA (B.A.B.); Department of Epidemiology, University of Iowa (J.C.T.); Department of Neurology, Mayo Clinic, Rochester, MN (R.D.B.); Division of Neurosurgery, St. Michael's Hospital, Keenan Research Centre for Biomedical Science and the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (R.L.M.); and Department of Surgery, University of Toronto, Toronto, Ontario, Canada (R.L.M.).
| | - Rita Dreier
- From the Department of Neurosurgery (N.E., K.B., H.-J.S., D.H.) and Institute of Forensic Medicine (C.M.), Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany; Institute for Physiological Chemistry and Pathobiochemistry, Westfalian Wilhelms-University, Münster, Germany (R.D., P.B.); Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, CA (B.A.B.); Department of Epidemiology, University of Iowa (J.C.T.); Department of Neurology, Mayo Clinic, Rochester, MN (R.D.B.); Division of Neurosurgery, St. Michael's Hospital, Keenan Research Centre for Biomedical Science and the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (R.L.M.); and Department of Surgery, University of Toronto, Toronto, Ontario, Canada (R.L.M.)
| | - Bruce A Buchholz
- From the Department of Neurosurgery (N.E., K.B., H.-J.S., D.H.) and Institute of Forensic Medicine (C.M.), Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany; Institute for Physiological Chemistry and Pathobiochemistry, Westfalian Wilhelms-University, Münster, Germany (R.D., P.B.); Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, CA (B.A.B.); Department of Epidemiology, University of Iowa (J.C.T.); Department of Neurology, Mayo Clinic, Rochester, MN (R.D.B.); Division of Neurosurgery, St. Michael's Hospital, Keenan Research Centre for Biomedical Science and the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (R.L.M.); and Department of Surgery, University of Toronto, Toronto, Ontario, Canada (R.L.M.)
| | - Kerim Beseoglu
- From the Department of Neurosurgery (N.E., K.B., H.-J.S., D.H.) and Institute of Forensic Medicine (C.M.), Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany; Institute for Physiological Chemistry and Pathobiochemistry, Westfalian Wilhelms-University, Münster, Germany (R.D., P.B.); Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, CA (B.A.B.); Department of Epidemiology, University of Iowa (J.C.T.); Department of Neurology, Mayo Clinic, Rochester, MN (R.D.B.); Division of Neurosurgery, St. Michael's Hospital, Keenan Research Centre for Biomedical Science and the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (R.L.M.); and Department of Surgery, University of Toronto, Toronto, Ontario, Canada (R.L.M.)
| | - Peter Bruckner
- From the Department of Neurosurgery (N.E., K.B., H.-J.S., D.H.) and Institute of Forensic Medicine (C.M.), Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany; Institute for Physiological Chemistry and Pathobiochemistry, Westfalian Wilhelms-University, Münster, Germany (R.D., P.B.); Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, CA (B.A.B.); Department of Epidemiology, University of Iowa (J.C.T.); Department of Neurology, Mayo Clinic, Rochester, MN (R.D.B.); Division of Neurosurgery, St. Michael's Hospital, Keenan Research Centre for Biomedical Science and the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (R.L.M.); and Department of Surgery, University of Toronto, Toronto, Ontario, Canada (R.L.M.)
| | - Christian Matzenauer
- From the Department of Neurosurgery (N.E., K.B., H.-J.S., D.H.) and Institute of Forensic Medicine (C.M.), Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany; Institute for Physiological Chemistry and Pathobiochemistry, Westfalian Wilhelms-University, Münster, Germany (R.D., P.B.); Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, CA (B.A.B.); Department of Epidemiology, University of Iowa (J.C.T.); Department of Neurology, Mayo Clinic, Rochester, MN (R.D.B.); Division of Neurosurgery, St. Michael's Hospital, Keenan Research Centre for Biomedical Science and the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (R.L.M.); and Department of Surgery, University of Toronto, Toronto, Ontario, Canada (R.L.M.)
| | - James C Torner
- From the Department of Neurosurgery (N.E., K.B., H.-J.S., D.H.) and Institute of Forensic Medicine (C.M.), Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany; Institute for Physiological Chemistry and Pathobiochemistry, Westfalian Wilhelms-University, Münster, Germany (R.D., P.B.); Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, CA (B.A.B.); Department of Epidemiology, University of Iowa (J.C.T.); Department of Neurology, Mayo Clinic, Rochester, MN (R.D.B.); Division of Neurosurgery, St. Michael's Hospital, Keenan Research Centre for Biomedical Science and the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (R.L.M.); and Department of Surgery, University of Toronto, Toronto, Ontario, Canada (R.L.M.)
| | - Robert D Brown
- From the Department of Neurosurgery (N.E., K.B., H.-J.S., D.H.) and Institute of Forensic Medicine (C.M.), Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany; Institute for Physiological Chemistry and Pathobiochemistry, Westfalian Wilhelms-University, Münster, Germany (R.D., P.B.); Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, CA (B.A.B.); Department of Epidemiology, University of Iowa (J.C.T.); Department of Neurology, Mayo Clinic, Rochester, MN (R.D.B.); Division of Neurosurgery, St. Michael's Hospital, Keenan Research Centre for Biomedical Science and the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (R.L.M.); and Department of Surgery, University of Toronto, Toronto, Ontario, Canada (R.L.M.)
| | - Hans-Jakob Steiger
- From the Department of Neurosurgery (N.E., K.B., H.-J.S., D.H.) and Institute of Forensic Medicine (C.M.), Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany; Institute for Physiological Chemistry and Pathobiochemistry, Westfalian Wilhelms-University, Münster, Germany (R.D., P.B.); Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, CA (B.A.B.); Department of Epidemiology, University of Iowa (J.C.T.); Department of Neurology, Mayo Clinic, Rochester, MN (R.D.B.); Division of Neurosurgery, St. Michael's Hospital, Keenan Research Centre for Biomedical Science and the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (R.L.M.); and Department of Surgery, University of Toronto, Toronto, Ontario, Canada (R.L.M.)
| | - Daniel Hänggi
- From the Department of Neurosurgery (N.E., K.B., H.-J.S., D.H.) and Institute of Forensic Medicine (C.M.), Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany; Institute for Physiological Chemistry and Pathobiochemistry, Westfalian Wilhelms-University, Münster, Germany (R.D., P.B.); Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, CA (B.A.B.); Department of Epidemiology, University of Iowa (J.C.T.); Department of Neurology, Mayo Clinic, Rochester, MN (R.D.B.); Division of Neurosurgery, St. Michael's Hospital, Keenan Research Centre for Biomedical Science and the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (R.L.M.); and Department of Surgery, University of Toronto, Toronto, Ontario, Canada (R.L.M.)
| | - R Loch Macdonald
- From the Department of Neurosurgery (N.E., K.B., H.-J.S., D.H.) and Institute of Forensic Medicine (C.M.), Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany; Institute for Physiological Chemistry and Pathobiochemistry, Westfalian Wilhelms-University, Münster, Germany (R.D., P.B.); Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, CA (B.A.B.); Department of Epidemiology, University of Iowa (J.C.T.); Department of Neurology, Mayo Clinic, Rochester, MN (R.D.B.); Division of Neurosurgery, St. Michael's Hospital, Keenan Research Centre for Biomedical Science and the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (R.L.M.); and Department of Surgery, University of Toronto, Toronto, Ontario, Canada (R.L.M.)
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