Neovascularization of poly(ether ester) block-copolymer scaffolds in vivo: long-term investigations using intravital fluorescent microscopy.

Poly(ether ester) block-copolymer scaffolds of different pore size were implanted into the dorsal skinfold chamber of balb/c mice. Using intravital fluorescent microscopy, the temporal course of neovascularization into these scaffolds was quantitatively analyzed. Three scaffold groups (diameter, 5 mm; 220-260 thickness, microm; n = 30) were implanted. Different pore sizes were evaluated: small (20-75 microm), medium (75-212 microm) and large pores (250-300 microm). Measurements were performed on days 8, 12, 16, and 20 in the surrounding normal tissue, in the border zone, and in the center of the scaffold. Standard microcirculatory parameters were assessed (plasma leakage, vessel diameter, red blood cell velocity, and functional vessel density). The large-pored scaffolds showed significantly higher functional vessel density in the border zone and in the center (days 8 and 12) compared with the scaffold with the small and medium-sized pores. These data correlated with a larger vessel diameter and a higher red blood cell velocity in the large-pored scaffold group. Interestingly, during the evaluation period the microcirculatory parameters on the edge of the scaffolds returned to values similar to those found in the surrounding tissue. In the center of the scaffold, however, neovascularization was still active 20 days after implantation. Plasma leakage and vessel diameter were higher in the center of the scaffold. Red blood cell velocity and functional vessel density were 50% lower than in the surrounding tissue. In conclusion, the dorsal skinfold chamber model in mice allows long-term study of blood vessel growth and remodeling in porous biomedical materials. The rate of vessel ingrowth into poly(ether ester) block-copolymer scaffolds is influenced by pore size and was highest in the scaffold with the largest pores. The data generated with this model contribute to knowledge about the development of functional vessels and tissue ingrowth into biomaterials.

[1]  L. Zentilin,et al.  Recombinant AAV vector encoding human VEGF165 enhances wound healing , 2002, Gene Therapy.

[2]  K. Messmer,et al.  Revascularization of Transplanted Adipose Tissue: A Study in the Dorsal Skinfold Chamber of Hamsters , 2002, Annals of plastic surgery.

[3]  Y. Ikada,et al.  Experimental Corneal Neovascularization by Basic Fibroblast Growth Factor Incorporated into Gelatin Hydrogel , 2000, Ophthalmic Research.

[4]  David J Mooney,et al.  Engineering and Characterization of Functional Human Microvessels in Immunodeficient Mice , 2001, Laboratory Investigation.

[5]  T Klyscz,et al.  [Cap image--a new kind of computer-assisted video image analysis system for dynamic capillary microscopy]. , 1997, Biomedizinische Technik. Biomedical engineering.

[6]  J. Veerkamp,et al.  Loading of collagen-heparan sulfate matrices with bFGF promotes angiogenesis and tissue generation in rats. , 2002, Journal of biomedical materials research.

[7]  Robert Langer,et al.  Local delivery of basic fibroblast growth factor increases both angiogenesis and engraftment of hepatocytes in tissue-engineered polymer devices1 , 2002, Transplantation.

[8]  Larry V McIntire,et al.  A technique for quantitative three-dimensional analysis of microvascular structure. , 2002, Microvascular research.

[9]  W. White,et al.  Magnetic Resonance Imaging versus Bone Scan for Assessment of Vascularization of the Hydroxyapatite Orbital Implant , 1996, Ophthalmic plastic and reconstructive surgery.

[10]  K. Messmer,et al.  In Vivo Assessment of Neovascularization and Incorporation of Prosthetic Vascular Biografts , 1992, The Thoracic and cardiovascular surgeon.

[11]  A. Goetz,et al.  Active and higher intracellular uptake of 5-aminolevulinic acid in tumors may be inhibited by glycine. , 1999, The Journal of investigative dermatology.

[12]  C. V. van Blitterswijk,et al.  Degradative behaviour of polymeric matrices in (sub)dermal and muscle tissue of the rat: a quantitative study. , 1994, Biomaterials.

[13]  K. Messmer,et al.  Neovascularization of prosthetic vascular grafts. Quantitative analysis of angiogenesis and microhemodynamics by means of intravital microscopy. , 1990, The Thoracic and cardiovascular surgeon.

[14]  K. Messmer,et al.  Microcirculatory models of ischaemia-reperfusion in skin and striated muscle. , 1995, International journal of microcirculation, clinical and experimental.

[15]  Anthony Atala,et al.  Systems for therapeutic angiogenesis in tissue engineering , 2000, World Journal of Urology.

[16]  C. V. van Blitterswijk,et al.  A new biodegradable matrix as part of a cell seeded skin substitute for the treatment of deep skin defects: a physico-chemical characterisation. , 1993, Clinical materials.

[17]  M. B. Claase,et al.  The different behaviors of skeletal muscle cells and chondrocytes on PEGT/PBT block copolymers are related to the surface properties of the substrate. , 2001, Journal of biomedical materials research.

[18]  C. V. van Blitterswijk,et al.  Bilayered biodegradable poly(ethylene glycol)/poly(butylene terephthalate) copolymer (Polyactive) as substrate for human fibroblasts and keratinocytes. , 1999, Journal of biomedical materials research.

[19]  K. Messmer,et al.  Dorsal skinfold chamber technique for intravital microscopy in nude mice. , 1993, The American journal of pathology.

[20]  J. Riesle,et al.  Static and dynamic fibroblast seeding and cultivation in porous PEO/PBT scaffolds , 1999, Journal of materials science. Materials in medicine.

[21]  P. Carmeliet.  Mechanisms of angiogenesis and arteriogenesis , 2000, Nature Medicine.

[22]  K Messmer,et al.  Orthogonal Polarization Spectral Imaging Versus Intravital Fluorescent Microscopy for Microvascular Studies in Wounds , 2002, Annals of plastic surgery.

[23]  K. Messmer,et al.  Technical report—a new chamber technique for microvascular studies in unanesthetized hamsters , 1980, Research in experimental medicine. Zeitschrift fur die gesamte experimentelle Medizin einschliesslich experimenteller Chirurgie.

[24]  K. Messmer,et al.  Functional capillary density: an indicator of tissue perfusion? , 1995, International journal of microcirculation, clinical and experimental.

[25]  E. Tsuchida,et al.  Constriction of resistance arteries determines l-NAME-induced hypertension in a conscious hamster model. , 2000, Microvascular research.

[26]  K. Messmer,et al.  Microvascular ischemia-reperfusion injury in striated muscle: significance of "reflow paradox". , 1992, The American journal of physiology.

[27]  J. Folkman.  Angiogenesis in cancer, vascular, rheumatoid and other disease , 1995, Nature Medicine.

[28]  K. Messmer,et al.  Skeletal muscle microvascular and tissue injury after varying durations of ischemia. , 1996, The American journal of physiology.

[29]  A G Harris,et al.  In vivo monitoring of microvessels in skin flaps: Introduction of a novel technique , 2001, Microsurgery.

[30]  C. V. van Blitterswijk,et al.  Application of porous PEO/PBT copolymers for bone replacement. , 1996, Journal of biomedical materials research.

[31]  Antonios G. Mikos,et al.  Pore Morphology Effects on the Fibrovascular Tissue Growth in Porous Polymer Substrates , 1994, Cell transplantation.

[32]  S. Bulstra,et al.  Femoral canal occlusion in total hip replacement using a resorbable and flexible cement restrictor. , 1996, The Journal of bone and joint surgery. British volume.

[33]  K. Messmer,et al.  Role of leukocyte plugging and edema in skeletal muscle ischemia-reperfusion injury. , 1997, The American journal of physiology.

[34]  K. Messmer,et al.  Orientation of microvascular blood flow in pancreatic islet isografts. , 1994, The Journal of clinical investigation.

[35]  C. V. van Blitterswijk,et al.  Dermal regeneration in full‐thickness wounds in Yucatan miniature pigs using a biodegradable copolymer , 1998, Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society.

[36]  C. Schmidt,et al.  Synthesis and characterization of polypyrrole-hyaluronic acid composite biomaterials for tissue engineering applications. , 2000, Journal of biomedical materials research.