title: Material properties of aged human mitral valve leaflets.
abstract: This study aimed to characterize the mechanical properties of aged human anterior mitral leaflets (AML) and posterior mitral leaflets (PML). The AML and PML samples from explanted human hearts (n = 21, mean age of 82.62 ± 8.77-years-old) were subjected to planar biaxial mechanical tests. The material stiffness, extensibility, and degree of anisotropy of the leaflet samples were quantified. The microstructure of the samples was assessed through histology. Both the AML and PML samples exhibited a nonlinear and anisotropic behavior with the circumferential direction being stiffer than the radial direction. The AML samples were significantly stiffer than the PML samples in both directions, suggesting that they should be modeled with separate sets of material properties in computational studies. Histological analysis indicated the changes in the tissue elastic constituents, including the fragmented and disorganized elastin network, the presence of fibrosis and proteoglycan/glycosaminoglycan infiltration and calcification, suggesting possible valvular degenerative characteristics in the aged human leaflet samples. Overall, stiffness increased and areal strain decreased with calcification severity. In addition, leaflet tissues from hypertensive individuals also exhibited a higher stiffness and low areal strain than normotensive individuals. There are significant differences in the mechanical properties of the two human mitral valve leaflets from this advanced age group. The morphologic changes in the tissue composition and structure also infer the structural and functional difference between aged human valves and those of animals.
authors.affiliation: Tissue Mechanics Laboratory, Department of Mechanical Engineering, Biomedical Engineering Program, University of Connecticut, Storrs, Connecticut, 06269.
authors.forename: Thuy
authors.initials: T
authors.lastname: Pham
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
mesh_terms: D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D016880:Anisotropy; D001696:Biomechanical Phenomena; D002114:Calcinosis / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008422:Materials Testing; D008943:Mitral Valve / Q000503:physiopathology*; D008955:Models, Cardiovascular; D059289:Vascular Stiffness
keywords: anterior mitral leaflet; human mitral valve; mechanical properties; planar biaxial test; posterior mitral leaflet
references.citation: J Biomech Eng. 2000 Feb;122(1):23-30
references.pmid: 10790826
references.citation: J Biomech. 2006;39(6):1153-7
references.pmid: 16549103
references.citation: Ann Biomed Eng. 2004 Dec;32(12):1599-606
references.pmid: 15675673
references.citation: J Biomech. 1986;19(5):399-404
references.pmid: 3733765
references.citation: Ann Biomed Eng. 2000 Sep;28(9):1093-100
references.pmid: 11132193
references.citation: Circulation. 2005 May 3;111(17):2183-9
references.pmid: 15851597
references.citation: Med Image Anal. 2012 Oct;16(7):1330-46
references.pmid: 22766456
references.citation: Ann Biomed Eng. 2006 May;34(5):823-32
references.pmid: 16619131
references.citation: J Am Coll Cardiol. 2004 Oct 19;44(8):1652-61
references.pmid: 15489099
references.citation: Cell Tissue Bank. 2006;7(3):183-94
references.pmid: 16933040
references.citation: J Mech Behav Biomed Mater. 2012 Feb;6:21-9
references.pmid: 22301170
references.citation: J Mech Behav Biomed Mater. 2010 Feb;3(2):167-77
references.pmid: 20129416
references.citation: Cardiovasc Surg. 1997 Aug;5(4):427-34
references.pmid: 9350801
references.citation: Catheter Cardiovasc Interv. 2003 Nov;60(3):410-6
references.pmid: 14571496
references.citation: Cryobiology. 1995 Oct;32(5):405-21
references.pmid: 7587281
references.citation: Ann Biomed Eng. 2002 Nov-Dec;30(10):1281-90
references.pmid: 12540204
references.citation: Ann Thorac Surg. 2010 Dec;90(6):1904-11; discussion 1912
references.pmid: 21095334
references.citation: Acta Biomater. 2008 Sep;4(5):1148-60
references.pmid: 18448399
references.citation: J Biomech. 2009 Aug 25;42(12):1909-16
references.pmid: 19535081
references.citation: Circulation. 2013 Apr 9;127(14):1485-92
references.pmid: 23459614
references.citation: Nat Rev Cardiol. 2010 Nov;7(11):648-59
references.pmid: 20924360
references.citation: Ann Vasc Surg. 1996 May;10(3):262-72
references.pmid: 8792995
references.citation: Am J Physiol Heart Circ Physiol. 2008 Sep;295(3):H1141-H1149
references.pmid: 18621858
references.citation: Chest. 1973 Apr;63(4):547-51
references.pmid: 4695351
references.citation: J Thorac Cardiovasc Surg. 1994 Jan;107(1):143-50; discussion 150-1
references.pmid: 8283877
references.citation: J Thorac Cardiovasc Surg. 1973 Aug;66(2):202-8
references.pmid: 4720973
references.citation: Am J Physiol Heart Circ Physiol. 2010 Feb;298(2):H395-405
references.pmid: 19915178
references.citation: J Vet Cardiol. 2012 Mar;14(1):7-17
references.pmid: 22364692
references.citation: J Biomech Eng. 2005 Jun;127(3):504-11
references.pmid: 16060357
references.citation: J Heart Valve Dis. 2003 Jul;12(4):488-94
references.pmid: 12918852
references.citation: Circulation. 2010 Feb 23;121(7):e46-e215
references.pmid: 20019324
references.citation: Thorax. 1977 Dec;32(6):691-6
references.pmid: 601730
references.citation: J Biomech. 1979;12(6):423-36
references.pmid: 457696
references.citation: Eur J Med Res. 1995 Dec 18;1(3):144-8
references.pmid: 9389676
references.citation: J Biomech Eng. 2004 Apr;126(2):244-51
references.pmid: 15179855
references.citation: J Surg Res. 2011 Dec;171(2):434-42
references.pmid: 20701927
references.citation: Phys Med Biol. 1995 Oct;40(10):1577-97
references.pmid: 8532741
references.citation: Int J Gen Med. 2012;5:839-43
references.pmid: 23077412
references.citation: J Biomech. 2012 Mar 15;45(5):903-7
references.pmid: 22281408
references.citation: Tissue Eng Part A. 2010 Mar;16(3):867-78
references.pmid: 19814589
references.citation: J Biomech Eng. 2008 Jun;130(3):031015
references.pmid: 18532864
references.citation: J Heart Valve Dis. 2002 Nov;11(6):810-22
references.pmid: 12479282
references.citation: Am J Physiol. 1995 Oct;269(4 Pt 2):H1319-27
references.pmid: 7485564
references.citation: J Vasc Surg. 1990 Nov;12(5):531-7
references.pmid: 2231964
references.citation: JACC Cardiovasc Imaging. 2010 Dec;3(12):1247-55
references.pmid: 21163453
references.citation: J Heart Valve Dis. 1993 May;2(3):326-40
references.pmid: 8269128
references.citation: J Surg Res. 2007 May 15;139(2):236-42
references.pmid: 17303171
references.citation: Ann Thorac Surg. 2006 Oct;82(4):1369-77
references.pmid: 16996935
references.citation: Cryobiology. 2009 Oct;59(2):171-9
references.pmid: 19591817
references.citation: Asian Cardiovasc Thorac Ann. 2006 Oct;14(5):394-8
references.pmid: 17005886
references.citation: Ann Thorac Surg. 2012 Apr;93(4):1141-5
references.pmid: 22397985
references.citation: J Heart Valve Dis. 2002 Jan;11 Suppl 1:S15-20
references.pmid: 11843514
references.citation: J Biomech. 2007;40(3):705-11
references.pmid: 16574127
references.citation: J Ky Med Assoc. 1989 Apr;87(4):177-80
references.pmid: 2723525
references.citation: J Biomech Eng. 2003 Jun;125(3):372-80
references.pmid: 12929242
references.citation: Tissue Eng. 2003 Dec;9(6):1089-100
references.pmid: 14670097
references.citation: J Thorac Cardiovasc Surg. 2001 Nov;122(5):955-62
references.pmid: 11689801
references.citation: Circulation. 2003 Oct 14;108(15):1795-7
references.pmid: 14530194
references.citation: J Card Surg. 1992 Mar;7(1):71-8
references.pmid: 1554980
references.citation: Glycobiology. 2004 Jul;14(7):621-33
references.pmid: 15044391
references.citation: Geriatrics. 1991 Apr;46(4):73-5, 79-80, 85-6
references.pmid: 2010097
references.citation: EuroIntervention. 2005 Nov;1(3):346-51
references.pmid: 19758928
references.citation: Ann Thorac Surg. 2010 May;89(5):1546-53
references.pmid: 20417775
references.citation: Circulation. 2004 Nov 9;110(19):3088-92
references.pmid: 15505086
references.citation: J Thorac Cardiovasc Surg. 1998 Nov;116(5):734-43
references.pmid: 9806380
references.citation: J Hypertens. 2009 Mar;27(3):535-42
references.pmid: 19330913
references.citation: Eur J Cardiothorac Surg. 2011 Jul;40(1):28-34
references.pmid: 21177118
references.citation: Ann Biomed Eng. 2006 Feb;34(2):315-25
references.pmid: 16450193
references.citation: Magn Reson Imaging. 2010 Feb;28(2):255-63
references.pmid: 19695819
references.citation: Lancet. 2006 Sep 16;368(9540):1005-11
references.pmid: 16980116
references.citation: Biomech Model Mechanobiol. 2009 Feb;8(1):43-55
references.pmid: 18193309
references.citation: J Biomech Eng. 2009 Dec;131(12):121010
references.pmid: 20524733
references.citation: J Biomed Mater Res A. 2012 Jun;100(6):1591-9
references.pmid: 22447518
references.citation: Magn Reson Med. 2011 Jan;65(1):261-8
references.pmid: 20878761
references.citation: Annu Rev Biomed Eng. 2003;5:251-84
references.pmid: 12730082
references.citation: J Heart Valve Dis. 1996 Jul;5(4):365-75
references.pmid: 8858500