Type V Collagen as a Low Thrombogenic Surface Coating for a Biological Vascular Prosthesis (original) (raw)
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In vivo evaluation of modified mandrel-grown vascular prostheses
Journal of Biomedical Materials Research, 1999
The Omniflow™ Vascular Prosthesis (OVP) has been manufactured and extensively tested in animal and human trials. It has mechanical and biological qualities superior to synthetic and biological conduits, particularly in low flow conditions. For further development into the smaller diameter coronary prostheses, the inner luminal surface is of paramount importance. In a previous study this inner surface was modified to produce a more uniformly thicker nonundulating surface. In this study the mandrels of these modified OVPs were treated with either collagen or heparin; the OVPs were evaluated for patency, tissue integration and wound healing, and endothelialization using a dog model comparable to that used to evaluate the unmodified OVP. In all instances, each of the modified prostheses were fully patent and had no signs of any deleterious effects caused by these modifications; no thrombus or aneurysms were visible. The tissue response was rapid with excellent new host collagen deposition within the vessel wall and minimal inflammatory and foreign body giant cells. Endothelialization was noted at the earliest explant time point in central regions of the prostheses, albeit that the histological picture at this time point appeared to reflect a complex atypical intimal layer.
Biological performances of collagen-based scaffolds for vascular tissue engineering
Biomaterials, 2005
Collagen is widely used for biomedical applications and it could represent a valid alternative scaffold material for vascular tissue engineering. In this work, reconstituted collagen films were prepared from neutralized acid-soluble solutions for subsequent haemocompatibility and cell viability performance assays. First, haemoglobin-free, thrombelastography and platelet adhesion tests were performed in order to investigate the blood contact performance. Secondly, specimens were seeded with endothelial cells and smooth muscle cells, and cell viability tests were carried out by MTT and SEM. Results show that neutralized acid-soluble type I collagen films do not enhance blood coagulation, do not alter normal viscoelastic properties of blood and slightly activate platelet adhesion and aggregation. Cell culture shows that the samples are adequate substrates to support the adhesion and proliferation of endothelial and smooth muscle cells.
Collagen coatings as biological sealants for textile arterial prostheses
Biomaterials, 1989
Two collagen-coated grafts were studied: Hemashield@ (bovine collagen cross-linked with formaldehyde vapours and softened by exposure to glycerol) and TascorP (collagen fibres cross-linked with glutaraldehyde solution). The weight of the coating was 310 f 5 mg/g for Hemashield@ and 45 f 2.5 mg/g for Tascon@. However, notwithstanding these differences, both coatings were efficient in making the walls of the grafts impervious to blood. The water permeabilities for the Hemashield@' and the Tascon@ were 8.7 and 5.9 ml.min-'.cm-2 at 120 mmHg respectively. The Hemashield@ collagen coating was rapidly eroded in vitro (4 h) after exposure to buffer, trypsin or pancreatin solutions, whereas the Tascon@ collagen coating remained well preserved after 7 d incubation. Both coatings were safe and did not interfere with the physical properties of the graft which was used as a skeleton. The healing properties of the HemashielF were similar to that observed with preclotted polyester prostheses, except in the early hours following graft implantation. On the other hand, the absence of erosion in the coating of the Tascon@ seemed to contribute to early antithrombogenicity. It also induced marked inflammatory reactions in the surrounding tissues and thus the healing appeared to be delayed.
In vivo Study of a Collagen Impregnated Polyester Arterial Prosthesis: the Arteknit Ra K ® Graft
Cor et vasa
In vivo Study of a Collagen Impregnated Polyester Arterial Prosthesis: the Arteknit Ra K ® Graft. Cor Vasa 2006;48(1):12–18. Purpose: We have previously reported that a transient increase in intracellular Ca 2+ concentrations in endothelial-like cells may reflect the endothelization process on the Arteknit Ra K ® polyester arterial prosthesis implanted in the aorta of mongrel dogs (Physiol Res 51; 217–20:2002). In this study, we further examine early arterial graft healing, i. e. patency, morphology, endothelization and thromboresistance, after short implantation periods in these dogs. Methods: We implanted 12 Arteknit Ra K ® prostheses in the aorta of mongrel dogs for scheduled periods ranging from 48 hours to 6 months. The explanted graft specimens were subjected to histological examination and scanning electron microscopy, analyzed for platelet and fibrinogen uptake as well as prostacyclin (PGI 2) and thromboxane A 2 (TXA 2) concentrations. Results: At the time of sacrifice, all ...
Effects of mesh modification on the structure of a mandrel-grown biosynthetic vascular prosthesis
Journal of Biomedical Materials Research, 1999
Mandrel-grown, mesh-reinforced vascular prostheses require adequate tissue coverage of the mesh for effective clinical function, particularly in low blood flow situations. Development of the ovine collagen-based Omni-flow™ vascular prosthesis has shown that the extent of this tissue cover is dependent on the interactions of the mandrel and the mesh with the sheep host. In the present study, the effects of chemical changes to the mesh have been examined. These data indicate that certain treatments of the mesh, par-ticularly collagen or heparin, lead to increased tissue coverage while the number of sheep cells present and the ultrastructure of the resulting vessel remain unchanged.
Journal of the American College of Cardiology, 1993
The Nrthrrlnnds: Frrrnhfi~r!. Gwmrtr~: Lcwcb~~. Ew!vc!. rxi: .Si 1,' York. Nrw York 04/ccrirs. The aim olthi study was w eraluate the satelI and l OIawy of a biwJrgradPblr collagen plug that hs been drrdopc,i to redwe the arbxid rmnpreslm time rquirrd tu arhir~. hsmostasis at the arterial puncture site atlrr diamtustic und latewenthnud camnary procedures. Rvckgmaraf. After diagnnstlc and intwvenliunal cornnary ca&&&adan procedures. to4 srtrrlat comprrrdun is rtquirrd tn &lew hem&r& aad ccmpltttiom may ensne. especially in path& 00 fall antJco&atton. .&f&edr. ftetneen March 1991 and July Mt. 252 pntlrntx admuted fer nmtlns comnllry anglogmphy "I suf,ioplusty to four M hmpllats received such a kexunstallc devii imuudtttel~ Wiih the increasing number of diagnostic cardiic cathewbations and themputic perctttattcous trnnsluminal coruntry pmcadures there is a growing need to limit hospital stay fur cost4fective
Inflammation and Neovascularization Associated with Clinically Used Vascular Prosthetic Materials
Cardiovascular Pathology, 1999
This study was designed to evaluate and compare healing characteristics, specifically neovascularization and inflammation, of polymeric vascular graft materials commonly used in clinical applications. Our hypotheses were (i) polymeric materials used in vascular graft manufacture stimulate chronic inflammation and (ii) inflammation and neovascularization of polymeric materials are related. Impra and Gore-Tex ePTFE, Meadox weavenit and woven Dacron, Hemashield microvel and woven Dacron, and Golaski microknit Dacron were implanted as 6-mm diameter disks within rat subcutaneous and adipose tissue. Following 5 weeks of implantation samples were evaluated by histological and immunocytochemical analysis. Sections were stained using hematoxylin and eosin or reacted with ED1 antibody and GS1 lectin to quantify inflammation and neovascularization, respectively. The extent of inflammation and neovascularization were influenced by both tissue site of implantation and polymer characteristics. For subcutaneous implants, inflammation was graded as follows: Meadox weavenit Ͼ Hemashield woven Ͼ Meadox woven Ͼ Gore-Tex ePTFE Ͼ Hemashield microvel Ͼ Impra ePTFE Ͼ Golaski microknit, while only the Golaski microknit neovascularized. Inflammation was graded as follows for adipose implants: Hemashield woven Ͼ Hemashield microvel Ͼ Meadox weavenit Ͼ Meadox woven Ͼ Gore-Tex ePTFE Ͼ Golaski microknit Ͼ Impra ePTFE, while the following order of neovascularization was observed: Impra ePTFE Ͼ Gore-Tex ePTFE Ͼ Golaski microknit. The degree of inflammation following biomaterial implantation has a profound effect on implant neovascularization. These data suggest an inverse relationship exists between inflammation and neovascularization.
Longterm study of a compliant biological vascular graft
European Journal of Vascular Surgery, 1991
Clinically implanted prostheses of biological origin have recently been shown to develop aneurysms within several years. To study this process, recently developed bovine heterografts that were implanted in canine ilio-femoral arteries for 27 to 45 months, were studied in vivo and in vitro. Seven out of seven grafts were patent with only one showing evidence of focal aneurysm. Measurements of mechanical properties, including water permeability, compliance, and burst pressure, and of heat shrink temperature and dry weight were obtained before and after a period of controlled exposure to bacterial collagenase; all data suggested that much of the original graft had been replaced with host tissue. However, enzyme susceptibility was less than that of fresh bovine arteries, indicating that at least some of the grafts" crosslinked collagen was preserved. The compliance of these explants was similar to that reported for autogenous vein. Histological examination of the graft wall revealed cellular "intimal" and adventitial zones containing host-generated collagen surrounding a central zone devoid of cellular infiltration, which appears to be unmodified graft "'media" highly resistant to degradation. We conclude that, when properly processed, biological prostheses can act as a bioresorbable scaffold for the orderly replacement of structural elements during healing, promoting continued mechanical integrity of the graft. These promising results encourage the further development of prostheses of biological origin.