Background: We hypothesized that an ideal heart valve replacement would be acellular valve root scaffolds seeded with autologous stem cells. To test this hypothesis, we prepared porcine acellular pulmonary valves, seeded them with autologous adipose derived stem cells (ADSCs) and implanted them in sheep and compared them to acellular valves.
Methods: Fresh porcine pulmonary valve roots were decellularized with detergents and enzymes. ADSCs were isolated from subdermal fat and injected within the acellular cusps. Valves were then implanted in an extra-anatomic pulmonary position as RV to PA shunts: Group A (n=6) consisted of acellular valves and Group B (n=6) of autologous stem cell-seeded acellular xenografts. Sheep were followed up for 6 months by echocardiography and histologic analysis was performed on explanted valves.
Results: Early evolution was favorable for both groups. All Group A animals had physiologic growth without any signs of heart failure and leaflets were found with preserved structure and mobility, lacking signs of thrombi, inflammation or calcification. Group B sheep however expressed signs of right ventricle failure starting at one month, accompanied by progressive regurgitation and right ventricle dilatation, and the leaflets were found covered with host tissue. No cells were found in any Group A or B explants.
Conclusions: Acellular stabilized xenogeneic pulmonary valves are reliable, stable, non-immunogenic, non-thrombogenic and non-calcifying scaffolds with excellent hemodynamics. Seeding these scaffolds with autologous ADSCs was not conducive to tissue regeneration. Studies aimed at understanding these novel observations and further harnessing the potential of stem cells are ongoing.
If the inline PDF is not rendering correctly, you can download the PDF file here.
1. Duran CG. [the Behavior of Aortic Valve Homo-grafts in Man and Animals]. Coeur Med Interne. 1964 Jul;64:301-5.
2. Simionescu DT, Chen J, Jaeggli M, Wang B, Liao J. Form Follows Function: Advances in Trilayered Structure Replication for Aortic Heart Valve Tissue Engineering. J Healthc Eng. 2012 Jun;3(2):179-202. DOI: 10.1260/2040-22184.108.40.206
3. Zilla P, Human P, Bezuidenhout D. Bioprosthetic heart valves: the need for a quantum leap. Biotechnol Appl Biochem. 2004 Aug;40(Pt 1):57-66.
4. Sohier J, Carubelli I, Sarathchandra P, Latif N, Chester AH, Yacoub MH. The potential of anisotropic matrices as substrate for heart valve engineering. Biomaterials. 2014 Feb;35(6):1833-44. DOI: 10.1016/j.biomaterials.2013.10.061
5. Weber B, Dijkman PE, Scherman J, Sanders B, Emmert MY, Grunenfelder J, et al. Off-the-shelf human decellularized tissue-engineered heart valves in a non-human primate model. Biomaterials. 2013 Oct;34(30):7269-80. DOI: 10.1016/j.biomaterials.2013.04.059
6. Tudorache I, Calistru A, Baraki H, Meyer T, Hoffler K, Sarikouch S, et al. Orthotopic replacement of aortic heart valves with tissue-engineered grafts. Tissue Eng Part A. 2013 Aug;19(15-16):1686-94. DOI: 10.1089/ten.tea.2012.0074
7. Tedder ME, Simionescu A, Chen J, Liao J, Simionescu DT. Assembly and testing of stem cell-seeded layered collagen constructs for heart valve tissue engineering. Tissue Eng Part A. 2011 Jan;17(1-2):25-36. DOI: 10.1089/ten.tea.2010.0138
8. Ku CH, Johnson PH, Batten P, Sarathchandra P, Chambers RC, Taylor PM, et al. Collagen synthesis by mesenchymal stem cells and aortic valve interstitial cells in response to mechanical stretch. Cardiovasc Res. 2006 Aug 1;71(3):548-56. DOI: 10.1016/j.cardiores.2006.03.022
9. Shinoka T, Ma PX, Shum-Tim D, Breuer CK, Cusick RA, Zund G, et al. Tissue-engineered heart valves. Autologous valve leaflet replacement study in a lamb model. Circulation. 1996 Nov 1;94(9 Suppl):II164-8.
10. Sierad LN, Simionescu A, Albers C, Chen J, Maivelett J, Tedder ME, et al. Design and Testing of a Pulsatile Conditioning System for Dynamic Endothelialization of Polyphenol-Stabilized Tissue Engineered Heart Valves. Cardiovasc Eng Technol. 2010 Jun;1(2):138-53. DOI: 10.1007/s13239-010-0014-6
11. Mercuri JJ, Patnaik S, Dion G, Gill SS, Liao J, Simionescu DT. Regenerative potential of decellularized porcine nucleus pulposus hydrogel scaffolds: stem cell differentiation, matrix remodeling, and biocompatibility studies. Tissue Eng Part A. 2013 Apr;19(7-8):952-66. DOI: 10.1089/ten.tea.2012.0088
12. Badylak SF. Decellularized allogeneic and xenogeneic tissue as a bioscaffold for regenerative medicine: factors that influence the host response. Ann Biomed Eng. 2014 Jul;42(7):1517-27. DOI: 10.1007/s10439-013-0963-7
13. Isenburg JC, Simionescu DT, Starcher BC, Vyavahare NR. Elastin stabilization for treatment of abdominal aortic aneurysms. Circulation. 2007 Apr 3;115(13):1729-37. DOI: 10.1161/CIRCULATIONAHA.106.672873
14. Chow JP, Simionescu DT, Warner H, Wang B, Patnaik SS, Liao J, et al. Mitigation of diabetes-related complications in implanted collagen and elastin scaffolds using matrix-binding polyphenol. Biomaterials. 2013 Jan;34(3):685-95. DOI: 10.1016/j.biomaterials.2012.09.081
15. Pennel T, Fercana G, Bezuidenhout D, Simionescu A, Chuang TH, Zilla P, et al. The performance of cross-linked acellular arterial scaffolds as vascular grafts; pre-clinical testing in direct and isolation loop circulatory models. Biomaterials. 2014 Aug;35(24):6311-22. DOI: 10.1016/j.biomaterials.2014.04.062
16. Colazzo F, Alrashed F, Saratchandra P, Carubelli I, Chester AH, Yacoub MH, et al. Shear stress and VEGF enhance endothelial differentiation of human adipose-derived stem cells. Growth Factors. 2014 Oct;32(5):139-49. DOI: 10.3109/08977194.2014.945642
17. Deac RF, Simionescu D, Deac D. New evolution in mitral physiology and surgery: mitral stentless pericardial valve. Ann Thorac Surg. 1995 Aug;60(2 Suppl):S433-8. DOI: 10.1016/0003-4975(95)00303-3
18. Tedder ME, Liao J, Weed B, Stabler C, Zhang H, Simionescu A, et al. Stabilized collagen scaffolds for heart valve tissue engineering. Tissue Eng Part A. 2009 Jun;15(6):1257-68. DOI: 10.1089/ten.tea.2008.0263
19. Gimble J, Guilak F. Adipose-derived adult stem cells: isolation, characterization, and differentiation potential. Cytotherapy. 2003;5(5):362-9. DOI: 10.1080/14653240310003026
20. Dijkman PE, Driessen-Mol A, Frese L, Hoerstrup SP, Baaijens FP. Decellularized homologous tissue-engineered heart valves as off-the-shelf alternatives to xeno- and homografts. Biomaterials. 2012 Jun;33(18):4545-54. DOI: 10.1016/j.biomaterials.2012.03.015
21. Schoen FJ, Levy RJ. Pathology of substitute heart valves: new concepts and developments. J Card Surg. 1994 Mar;9(2 Suppl):222-7. DOI: 10.1111/j.1540-8191.1994.tb00932.x
22. Chuang TH, Stabler C, Simionescu A, Simionescu DT. Polyphenol-stabilized tubular elastin scaffolds for tissue engineered vascular grafts. Tissue Eng Part A. 2009 Oct;15(10):2837-51. DOI: 10.1089/ten.tea.2008.0394
23. Paniagua Gutierrez JR, Berry H, Korossis S, Mirsadraee S, Lopes SV, da Costa F, et al. Regenerative potential of low-concentration SDS-decellularized porcine aortic valved conduits in vivo. Tissue Eng Part A. 2015 Jan;21(1-2):332-42. DOI: 10.1089/ten.tea.2014.0003
25. Lisy M, Pennecke J, Brockbank KG, Fritze O, Schleicher M, Schenke-Layland K, et al. The performance of ice-free cryopreserved heart valve allografts in an orthotopic pulmonary sheep model. Biomaterials. 2010 Jul;31(20):5306-11. DOI: 10.1016/j.biomaterials.2010.03.038
26. Hopkins RA, Jones AL, Wolfinbarger L, Moore MA, Bert AA, Lofland GK. Decellularization reduces calcification while improving both durability and 1-year functional results of pulmonary homograft valves in juvenile sheep. J Thorac Cardiovasc Surg. 2009 Apr;137(4):907-13, 13e1-4.
27. Shinoka T, Breuer CK, Tanel RE, Zund G, Miura T, Ma PX, et al. Tissue engineering heart valves: valve leaflet replacement study in a lamb model. Ann Thorac Surg. 1995 Dec;60(6 Suppl):S513-6. DOI: 10.1016/0003-4975(95)00733-4
28. Hopkins RA, Bert AA, Hilbert SL, Quinn RW, Brasky KM, Drake WB, et al. Bioengineered human and allogeneic pulmonary valve conduits chronically implanted orthotopically in baboons: hemodynamic performance and immunologic consequences. J Thorac Cardiovasc Surg. 2013 Apr;145(4):1098-107. DOI: 10.1016/j. jtcvs.2012.06.024
29. Khorramirouz R, Sabetkish S, Akbarzadeh A, Muhammadnejad A, Heidari R, Kajbafzadeh AM. Effect of three decellularisation protocols on the mechanical behaviour and structural properties of sheep aortic valve conduits. Adv Med Sci. 2014 Sep;59(2):299-307. DOI: 10.1016/j.advms.2014.08.004
30. Fallon AM, Goodchild TT, Cox JL, Matheny RG. In vivo remodeling potential of a novel bioprosthetic tricuspid valve in an ovine model. J Thorac Cardiovasc Surg. 2014 Jul;148(1):333-40 e1.
31. Lichtenberg A, Cebotari S, Tudorache I, Sturz G, Winterhalter M, Hilfiker A, et al. Flow-dependent re-endothelialization of tissue-engineered heart valves. J Heart Valve Dis. 2006 Mar;15(2):287-93; discussion 93-4.
32. Dohmen PM, Ozaki S, Yperman J, Flameng W, Konertz W. Lack of calcification of tissue engineered heart valves in juvenile sheep. Semin Thorac Cardiovasc Surg. 2001 Oct;13(4 Suppl 1):93-8.
33. Goldstein S, Clarke DR, Walsh SP, Black KS, O’Brien MF. Transpecies heart valve transplant: advanced studies of a bioengineered xeno-autograft. Ann Thorac Surg. 2000 Dec;70(6):1962-9. DOI: 10.1016/S0003-4975(00)01812-9
34. O’Brien MF, Goldstein S, Walsh S, Black KS, Elkins R, Clarke D. The SynerGraft valve: a new acellular (nonglutaraldehyde-fixed) tissue heart valve for autologous recellularization first experimental studies before clinical implantation. Semin Thorac Cardiovasc Surg. 1999 Oct;11(4 Suppl 1):194-200.
35. Simionescu A, Simionescu D, Deac R. Biochemical pathways of tissue degeneration in bioprosthetic cardiac valves. The role of matrix metalloproteinases. ASAIO J. 1996 Sep-Oct;42(5):M561-7. DOI: 10.1097/00002480-199609000-00049
37. Hilbert SL, Yanagida R, Souza J, Wolfinbarger L, Jones AL, Krueger P, et al. Prototype anionic detergent technique used to decellularize allograft valve conduits evaluated in the right ventricular outflow tract in sheep. J Heart Valve Dis. 2004 Sep;13(5):831-40.
38. Hopkins RA. Right ventricular outflow tract reconstructions: the role of valves in the viable allograft era. Ann Thorac Surg. 1988 Jun;45(6):593-4. DOI: 10.1016/S0003-4975(10)64757-1
39. Semon JA, Maness C, Zhang X, Sharkey SA, Beuttler MM, Shah FS, et al. Comparison of human adult stem cells from adipose tissue and bone marrow in the treatment of experimental autoimmune encephalomyelitis. Stem Cell Res Ther. 2014;5(1):2. DOI: 10.1186/scrt391
40. Gimble JM, Bunnell BA, Frazier T, Rowan B, Shah F, Thomas-Porch C, et al. Adipose-derived stromal/stem cells: a primer. Organogenesis. 2013 Jan-Mar;9(1):3-10. DOI: 10.4161/org.24279