title: Cardiogenic differentiation of mesenchymal stem cells on elastomeric poly (glycerol sebacate)/collagen core/shell fibers.
abstract: OBJECTIVE
  To facilitate engineering of suitable biomaterials to meet the challenges associated with myocardial infarction.
  
  
  METHODS
  Poly (glycerol sebacate)/collagen (PGS/collagen) core/shell fibers were fabricated by core/shell electrospinning technique, with core as PGS and shell as collagen polymer; and the scaffolds were characterized by scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), contact angle and tensile testing for cardiac tissue engineering. Collagen nanofibers were also fabricated by electrospinning for comparison with core/shell fibers. Studies on cell-scaffold interaction were carried out using cardiac cells and mesenchymal stem cells (MSCs) co-culture system with cardiac cells and MSCs separately serving as positive and negative controls respectively. The co-culture system was characterized for cell proliferation and differentiation of MSCs into cardiomyogenic lineage in the co-culture environment using dual immunocytochemistry. The co-culture cells were stained with cardiac specific marker proteins like actinin and troponin and MSC specific marker protein CD 105 for proving the cardiogenic differentiation of MSCs. Further the morphology of cells was analyzed using SEM.
  
  
  RESULTS
  PGS/collagen core/shell fibers, core is PGS polymer having an elastic modulus related to that of cardiac fibers and shell as collagen, providing natural environment for cellular activities like cell adhesion, proliferation and differentiation. SEM micrographs of electrospun ﬁbrous scaffolds revealed porous, beadless, uniform fibers with a fiber diameter in the range of 380 ± 77 nm and 1192 ± 277 nm for collagen fibers and PGS/collagen core/shell fibers respectively. The obtained PGS/collagen core/shell fibrous scaffolds were hydrophilic having a water contact angle of 17.9 ± 4.6° compared to collagen nanofibers which had a contact angle value of 30 ± 3.2°. The PGS/collagen core/shell fibers had mechanical properties comparable to that of native heart muscle with a young's modulus of 4.24 ± 0.7 MPa, while that of collagen nanofibers was comparatively higher around 30.11 ± 1.68 MPa. FTIR spectrum was performed to confirm the functional groups present in the electrospun scaffolds. Amide I and amide II of collagen were detected at 1638.95 cm(-1) and 1551.64 cm(-1) in the electrospun collagen fibers and at 1646.22 cm(-1) and 1540.73 cm(-1) for PGS/collagen core/shell fibers respectively. Cell culture studies performed using MSCs and cardiac cells co-culture environment, indicated that the cell proliferation significantly increased on PGS/collagen core/shell scaffolds compared to collagen fibers and the cardiac marker proteins actinin and troponin were expressed more on PGS/collagen core/shell scaffolds compared to collagen fibers alone. Dual immunofluorescent staining was performed to further confirm the cardiogenic differentiation of MSCs by employing MSC specific marker protein, CD 105 and cardiac specific marker protein, actinin. SEM observations of cardiac cells showed normal morphology on PGS/collagen fibers and providing adequate tensile strength for the regeneration of myocardial infarction.
  
  
  CONCLUSIONS
  Combination of PGS/collagen fibers and cardiac cells/MSCs co-culture system providing natural microenvironments to improve cell survival and differentiation, could bring cardiac tissue engineering to clinical application.
authors.affiliation: Rajeswari Ravichandran, Jayarama Reddy Venugopal, Subramanian Sundarrajan, Shayanti Mukherjee, Seeram Ramakrishna, Faculty of Engineering, Nanoscience and Nanotechnology Initiative, National University of Singapore, Singapore 117576, Singapore.
authors.forename: Rajeswari
authors.initials: R
authors.lastname: Ravichandran
authors.forename: Jayarama Reddy
authors.initials: JR
authors.lastname: Venugopal
authors.forename: Subramanian
authors.initials: S
authors.lastname: Sundarrajan
authors.forename: Shayanti
authors.initials: S
authors.lastname: Mukherjee
authors.forename: Seeram
authors.initials: S
authors.lastname: Ramakrishna
keywords: Cardiac cells; Cardiac patch; Co-culture; Core/shell fibers.; Mesenchymal stem cells; Poly (glycerol sebacate)
references.citation: Tissue Eng Part A. 2011 May;17(9-10):1363-73
references.pmid: 21247338
references.citation: J Biol Chem. 2004 Dec 3;279(49):51141-7
references.pmid: 15385548
references.citation: Nat Med. 2006 Apr;12(4):452-8
references.pmid: 16582915
references.citation: Endothelium. 2004 May-Aug;11(3-4):199-206
references.pmid: 15370297
references.citation: Int J Cancer. 1994 Jul 15;58(2):233-9
references.pmid: 7517919
references.citation: Mol Ther. 2006 Dec;14(6):840-50
references.pmid: 16965940
references.citation: Biomaterials. 2012 Jan;33(3):846-55
references.pmid: 22048006
references.citation: Acta Biomater. 2009 Oct;5(8):2929-38
references.pmid: 19457460
references.citation: Am J Physiol Heart Circ Physiol. 2008 Dec;295(6):H2257-63
references.pmid: 18835924
references.citation: Eur J Cardiothorac Surg. 2000 May;17(5):587-91
references.pmid: 10814924
references.citation: Biotechnol Bioeng. 2003 May 20;82(4):403-14
references.pmid: 12632397
references.citation: Ann Thorac Surg. 2005 Mar;79(3):881-7; discussion 881-7
references.pmid: 15734399
references.citation: Circulation. 2008 Mar 18;117(11):1388-96
references.pmid: 18316487
references.citation: J Clin Invest. 2006 Jan;116(1):237-48
references.pmid: 16357943
references.citation: Cell. 2004 Sep 3;118(5):649-63
references.pmid: 15339668
references.citation: Circulation. 1999 Jan 5-12;99(1):135-42
references.pmid: 9884390
references.citation: Pathol Res Pract. 1994 Oct;190(9-10):854-63
references.pmid: 7534913
references.citation: Muscle Nerve. 1995 Dec;18(12):1417-26
references.pmid: 7477065
references.citation: Circ Res. 2000 May 26;86(10):1062-8
references.pmid: 10827136
references.citation: J Biol Chem. 2004 Dec 31;279(53):55651-8
references.pmid: 15491989
references.citation: Heart Lung. 1999 Mar-Apr;28(2):87-101
references.pmid: 10076108
references.citation: Med Biol Eng Comput. 2000 Mar;38(2):211-8
references.pmid: 10829416
references.citation: J Tissue Eng Regen Med. 2007 Sep-Oct;1(5):327-42
references.pmid: 18038427
references.citation: J Biomed Mater Res A. 2003 Jul 1;66(1):192-7
references.pmid: 12833446
references.citation: Circ Res. 1996 Feb;78(2):283-8
references.pmid: 8575072
references.citation: Curr Opin Biotechnol. 2003 Oct;14(5):551-8
references.pmid: 14580588
references.citation: FASEB J. 2007 Oct;21(12):3197-207
references.pmid: 17496162
references.citation: Cell Transplant. 2006;15 Suppl 1:S29-40
references.pmid: 16826793
references.citation: Physiol Rev. 2003 Jan;83(1):59-115
references.pmid: 12506127
references.citation: Adv Drug Deliv Rev. 2009 Oct 5;61(12):1007-19
references.pmid: 19651166
references.citation: FASEB J. 2006 May;20(7):811-27
references.pmid: 16675838
references.citation: FASEB J. 1997 Jul;11(8):683-94
references.pmid: 9240969
references.citation: Tissue Eng. 2005 Sep-Oct;11(9-10):1574-88
references.pmid: 16259611
references.citation: Biomaterials. 2007 Sep;28(25):3587-93
references.pmid: 17524477
references.citation: FASEB J. 2005 Feb;19(2):275-7
references.pmid: 15574489
references.citation: Biomed Mater. 2012 Feb;7(1):015001
references.pmid: 22156014
references.citation: Circulation. 2005 Aug 30;112(9 Suppl):I135-43
references.pmid: 16159805
references.citation: Nat Med. 1998 Aug;4(8):929-33
references.pmid: 9701245
references.citation: Heart Fail Rev. 2005 Jun;10(2):101-7
references.pmid: 16258717
references.citation: Nat Biotechnol. 2002 Jun;20(6):602-6
references.pmid: 12042865
references.citation: Cell. 2006 Aug 25;126(4):677-89
references.pmid: 16923388
references.citation: J Natl Cancer Inst. 1991 Jun 5;83(11):769-74
references.pmid: 1789823
references.citation: J Am Coll Cardiol. 2006 May 2;47(9):1777-85
references.pmid: 16682301
references.citation: J Clin Invest. 2001 Aug;108(3):407-14
references.pmid: 11489934
references.citation: Biomaterials. 2008 Jan;29(1):47-57
references.pmid: 17915309
references.citation: J Am Coll Cardiol. 1989 Jun;13(7):1637-52
references.pmid: 2656824
references.citation: J Biomater Sci Polym Ed. 2004;15(5):645-60
references.pmid: 15264665
references.citation: Circ Res. 2002 Feb 8;90(2):223-30
references.pmid: 11834716
references.citation: Nat Med. 1999 Jun;5(6):662-8
references.pmid: 10371505
references.citation: Trends Cell Biol. 2004 Apr;14(4):160-6
references.pmid: 15066633
references.citation: J Biomed Mater Res A. 2007 Dec 15;83(4):1070-1075
references.pmid: 17584900
references.citation: Circulation. 2006 Jul 4;114(1 Suppl):I167-73
references.pmid: 16820568
references.citation: Circ Res. 2006 Jun 9;98(11):1414-21
references.pmid: 16690882
references.citation: Proc Natl Acad Sci U S A. 2004 Dec 28;101(52):18129-34
references.pmid: 15604141
references.citation: Circulation. 2003 Sep 16;108(11):1395-403
references.pmid: 12975244
references.citation: Int J Biochem Cell Biol. 2006 Jan;38(1):30-42
references.pmid: 16154797
references.citation: Fa Yi Xue Za Zhi. 2003;19(4):242-4
references.pmid: 14671803
references.citation: World J Stem Cells. 2009 Dec 31;1(1):55-66
references.pmid: 21607108
references.citation: Circulation. 2005 Aug 30;112(9 Suppl):I173-7
references.pmid: 16159811
references.citation: Int J Cardiol. 2013 Aug 20;167(4):1461-8
references.pmid: 22564386