Directionally Guided Angiogenesis Within Extruded Type I Collagen Filaments In Vivo

• Published in: Journal of histotechnology 2006-12, Vol.29 (4), p.267-276
• Main Authors: Speer, Donald P., Ulreich, Judith B., Young, Naomi J., Yuen, Debbie, Li, Shu-Tung
• Format: Article
• Language: English
• Subjects: angiogenesis; anterior cruciate ligament (ACL); basic fibroblast growth factor (bFGF); canine; collagen type I; crosslinking; glutaraldehyde; glyceraldehyde; heparin; in vivo; polarized light microscopy
• ISSN: 0147-8885; 2046-0236
• DOI: 10.1179/his.2006.29.4.267

Two types of crosslinked extruded type I collagen filaments were developed and characterized for implantation into canine knee joints to achieve anterior cruciate ligament (ACL) regeneration. Type A filaments were crosslinked with glutaraldehyde. Type B filaments were crosslinked with glyceraldehyde and treated with heparin and basic fibroblast growth factor (bFGF). Microscopic evaluation of the filaments revealed a gradient in the degree of crosslinking, with the surface of the filaments more highly crosslinked than the interior. The heterogeneous nature of the crosslinking was demonstrated by complementary methods using bright-field and polarized light microscopy imaging of differentially stained histological sections. In vivo, in the canine model of ACL replacement, the interior of the Type A filaments was degraded or resorbed well before the surface, thus creating collagen tubes through which new capillary channels developed. This phenomenon was not observed for the Type B collagen filaments that were degraded or resorbed from the periphery of each filament. The in vivo behavior of individual collagen filament types is correlated with the fabrication methods. The results suggest a novel method with which to achieve directionally guided angiogenesis (The J Histotechnol 29:267, 2006). Submitted October 1, 2006; accepted with revisions November 2, 2006