title: In Situ Tissue Engineering of Functional Small-Diameter Blood Vessels by Host Circulating Cells Only.
abstract: Inflammation is a natural phase of the wound healing response, which can be harnessed for the in situ tissue engineering of small-diameter blood vessels using instructive, bioresorbable synthetic grafts. This process is dependent on colonization of the graft by host circulating cells and subsequent matrix formation. Typically, vascular regeneration in small animals is governed by transanastomotic cell ingrowth. However, this process is very rare in humans and hence less relevant for clinical translation. Therefore, a novel rat model was developed, in which cell ingrowth from the adjacent tissue is inhibited using Gore-Tex sheathing. Using this model, our aim here was to prove that functional blood vessels can be formed in situ through the host inflammatory response, specifically by blood-borne cells. The model was validated by implanting sex-mismatched aortic segments on either anastomoses of an electrospun poly(ɛ-caprolactone) (PCL) graft, filled with fibrin gel, into the rat abdominal aorta. Fluorescent in situ hybridization analysis revealed that after 1 and 3 months in vivo, over 90% of infiltrating cells originated from the bloodstream, confirming the effective shielding of transanastomotic cell ingrowth. Using the validated model, PCL/fibrin grafts were implanted, either or not loaded with monocyte chemotactic protein-1 (MCP-1), and cell infiltration and tissue development were investigated at various key time points in the healing cascade. A phased healing response was observed, initiated by a rapid influx of inflammatory cells, mediated by the local release of MCP-1. After 3 months in vivo, the grafts consisted of a medial layer with smooth muscle cells in an oriented collagen matrix, an intimal layer with elastin fibers, and confluent endothelium. This study proves the regenerative potential of cells in the circulatory system in the setting of in situ vascular tissue engineering.
authors.affiliation: 1 Department of Cardiothoracic Surgery, University Medical Center Utrecht , Utrecht, The Netherlands .
authors.forename: Hanna
authors.initials: H
authors.lastname: Talacua
authors.affiliation: 2 Department of Biomedical Engineering, Eindhoven University of Technology , Eindhoven, The Netherlands .
authors.forename: Anthal I P M
authors.initials: AI
authors.lastname: Smits
authors.affiliation: 3 Department of Nephrology and Hypertension, University Medical Center Utrecht , Utrecht, The Netherlands .
authors.forename: Dimitri E P
authors.initials: DE
authors.lastname: Muylaert
authors.affiliation: 4 Department of Pathology, University Medical Center Utrecht , Utrecht, The Netherlands .
authors.forename: Jan Willem
authors.initials: JW
authors.lastname: van Rijswijk
authors.affiliation: 4 Department of Pathology, University Medical Center Utrecht , Utrecht, The Netherlands .
authors.forename: Aryan
authors.initials: A
authors.lastname: Vink
authors.affiliation: 3 Department of Nephrology and Hypertension, University Medical Center Utrecht , Utrecht, The Netherlands .
authors.forename: Marianne C
authors.initials: MC
authors.lastname: Verhaar
authors.affiliation: 2 Department of Biomedical Engineering, Eindhoven University of Technology , Eindhoven, The Netherlands .
authors.forename: Anita
authors.initials: A
authors.lastname: Driessen-Mol
authors.affiliation: 1 Department of Cardiothoracic Surgery, University Medical Center Utrecht , Utrecht, The Netherlands .
authors.forename: Lex A
authors.initials: LA
authors.lastname: van Herwerden
authors.affiliation: 2 Department of Biomedical Engineering, Eindhoven University of Technology , Eindhoven, The Netherlands .|5 Institute for Complex Molecular Systems , Eindhoven, The Netherlands .
authors.forename: Carlijn V C
authors.initials: CV
authors.lastname: Bouten
authors.affiliation: 1 Department of Cardiothoracic Surgery, University Medical Center Utrecht , Utrecht, The Netherlands .
authors.forename: Jolanda
authors.initials: J
authors.lastname: Kluin
authors.affiliation: 2 Department of Biomedical Engineering, Eindhoven University of Technology , Eindhoven, The Netherlands .|5 Institute for Complex Molecular Systems , Eindhoven, The Netherlands .
authors.forename: Frank P T
authors.initials: FP
authors.lastname: Baaijens
mesh_terms: D000818:Animals; D001807:Blood Vessel Prosthesis; D018932:Chemokine CCL2 / Q000378:metabolism; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000166:cytology; D011091:Polyesters / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry
chemical_list: D018932:Chemokine CCL2; D011091:Polyesters