Gel structure has an impact on pericellular and extracellular matrix deposition, which subsequently alters metabolic activities in chondrocyte-laden PEG hydrogels.
While designing poly(ethylene glycol) hydrogels with high moduli suitable for in situ placement is attractive for cartilage regeneration, the impact of a tighter crosslinked structure on the organization and deposition of the matrix is not fully understood. The objectives of this study were to characterize the composition and spatial organization of new matrix as a function of gel crosslinking and study its impact on chondrocytes in terms of anabolic and catabolic gene expression and catabolic activity. Bovine articular chondrocytes were encapsulated in hydrogels with three crosslinking densities (compressive moduli 60, 320 and 590 kPa) and cultured for 25 days. Glycosaminoglycan production increased with culture time and was greatest in the gels with lowest crosslinking. Collagens II and VI, aggrecan, link protein and decorin were localized to pericellular regions in all gels, but their presence decreased with increasing gel crosslinking. Collagen II and aggrecan expression were initially up-regulated in gels with higher crosslinking, but increased similarly up to day 15. Matrix metalloproteinase (MMP)-1 and MMP-13 expression were elevated (∼25-fold) in gels with higher crosslinking throughout the study, while MMP-3 was unaffected by gel crosslinking. The presence of aggrecan and collagen degradation products confirmed MMP activity. These findings indicate that chondrocytes synthesized the major cartilage components within PEG hydrogels, however, gel structure had a significant impact on the composition and spatial organization of the new tissue and on how chondrocytes responded to their environment, particularly with respect to their catabolic expression.
Nicodemus
G D
GD
Department of Chemical and Biological Engineering, ECCH 111, Campus Box 424, University of Colorado-Boulder, Boulder, CO 80309, USA.
Skaalure
S C
SC
Bryant
S J
SJ
D000818:Animals; D002417:Cattle; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000494:pharmacology; D005109:Extracellular Matrix / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006025:Glycosaminoglycans / Q000378:metabolism; D020100:Hydrogels / Q000737:chemistry* / Q000494:pharmacology*; D007150:Immunohistochemistry; D008689:Methacrylates / Q000494:pharmacology*; D010446:Peptide Fragments / Q000378:metabolism; D011092:Polyethylene Glycols / Q000494:pharmacology*; D011509:Proteoglycans / Q000378:metabolism; D012995:Solubility / Q000187:drug effects
D003432:Cross-Linking Reagents; D016326:Extracellular Matrix Proteins; D006025:Glycosaminoglycans; D020100:Hydrogels; D008689:Methacrylates; D010446:Peptide Fragments; D011509:Proteoglycans; C421283:poly(ethylene glycol)-dimethacrylate; D011092:Polyethylene Glycols
Biomaterials. 2006 Oct;27(30):5268-76
16797067
Tissue Eng. 2007 Apr;13(4):683-91
17266401
Osteoarthritis Cartilage. 2008 Aug;16(8):909-18
18203631
Biochim Biophys Acta. 1972 Sep 15;279(2):401-5
4263642
Osteoarthritis Cartilage. 2007 Oct;15(10):1207-16
17524677
Arch Biochem Biophys. 2001 Dec 1;396(1):49-55
11716461
Biomaterials. 2005 Oct;26(30):5991-8
15878198
Ann Biomed Eng. 2004 Jan;32(1):35-49
14964720
Osteoarthritis Cartilage. 2006 Feb;14(2):95-100
16257242
J Orthop Res. 1987;5(4):509-22
3681525
J Anat. 1997 Jul;191 ( Pt 1):1-13
9279653
J Cell Biol. 1986 Mar;102(3):703-10
3456350
J Biomed Mater Res. 2000 Aug;51(2):164-71
10825215
FEBS Lett. 2004 Sep 10;574(1-3):95-100
15358546
Biotechnol Bioeng. 2006 Dec 20;95(6):1061-9
16921532
Ann N Y Acad Sci. 2002 Jun;961:118-22
12081878
Biomaterials. 2009 Feb;30(4):518-25
19000634
J Cell Sci. 1995 Apr;108 ( Pt 4):1497-508
7615670
Nature. 1976 Apr 29;260(5554):808-9
1264261
Ann N Y Acad Sci. 2006 Apr;1068:498-512
16831947
J Biomed Mater Res A. 2003 Jan 1;64(1):70-9
12483698
J Biomed Mater Res A. 2009 Sep 1;90(3):720-9
18570315
J Biomed Mater Res. 2002 Jan;59(1):63-72
11745538
Biochem Soc Trans. 1990 Oct;18(5):812-5
2083684
J Biomech. 2008;41(7):1528-36
18417139
J Biomech. 2004 May;37(5):595-604
15046988
J Orthop Res. 2002 Jul;20(4):842-8
12168676
Cell. 2006 Aug 25;126(4):677-89
16923388
Front Biosci. 2007 Jan 01;12:507-27
17127313
Pharm Res. 2008 Oct;25(10):2379-86
18509600
J Biomed Mater Res A. 2003 Dec 15;67(4):1430-6
14624532
Ann Biomed Eng. 2004 Mar;32(3):407-17
15095815
J Biol Chem. 1992 Mar 15;267(8):5250-6
1544908
Osteoarthritis Cartilage. 2010 Jan;18(1):126-37
19748607
J Rheumatol Suppl. 1995 Feb;43:86-90
7752148
Acta Biomater. 2005 Mar;1(2):243-52
16701801
Biomacromolecules. 2006 Jun;7(6):1968-75
16768421
Matrix Biol. 2002 Jun;21(4):349-59
12128072
Proc Natl Acad Sci U S A. 2002 Jul 23;99(15):9996-10001
12119393
Biotechnol Bioeng. 2009 Mar 1;102(4):1242-50
18949761
Biochim Biophys Acta. 1986 Sep 4;883(2):173-7
3091074
J Biol Chem. 2003 Sep 26;278(39):37698-704
12840020
FASEB J. 1992 Feb 1;6(3):861-70
1740236
J Orthop Res. 2004 Sep;22(5):1143-9
15304291
J Biomech Eng. 1991 Aug;113(3):245-58
1921350
Osteoarthritis Cartilage. 2003 Dec;11(12):879-90
14629964
Biochem J. 1989 Mar 15;258(3):875-80
2730571
Biochem J. 1979 Jan 1;177(1):237-47
34388
Matrix Biol. 2006 Aug;25(6):323-31
16697175
Tissue Eng Part B Rev. 2008 Jun;14(2):149-65
18498217
J Biomech. 2007;40(5):1011-23
16793050
Biomaterials. 2007 Jan;28(2):134-46
17011028
J Biomed Mater Res A. 2004 Sep 15;70(4):560-8
15307160
Osteoarthritis Cartilage. 2008 Sep;16(9):1092-100
18294870
Tissue Eng. 2003 Aug;9(4):597-611
13678439
Biotechnol Bioeng. 2004 Jun 30;86(7):747-55
15162450
Cell. 1991 Mar 8;64(5):867-9
2001586
J Biol Chem. 1998 Jan 23;273(4):1923-32
9442026