Cytosolic free Ca2+ concentration in canine aortic endothelial cells lining the polyester arterial prosthesis (original) (raw)
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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 ...
Biomaterials, 2001
Background: Glutaraldehyde-related cytotoxicity and transanastomotic ingrowth inhibition prevent the spontaneous endothelialization of bioprosthetic heart valves. In order to evaluate the ability of improved biocompatibility to reduce tissue degeneration, conventionally "xed aortic root prostheses were both glutaraldehyde-detoxi"ed and in vitro endothelialized. Methods: Entire aortic roots were "xed in 0.2% glutaraldehyde (GA) (control group) and either detoxi"ed in acetic acid-bu!ered urazole (0.1 M) or detoxi"ed and in vitro lined with cultured, autologous jugular vein endothelial cells. The valved roots were inserted in the distal aortic arch of 15 juvenile Merino sheep for a period of 12 weeks. Upon explant, lea#ets, sinuses and aortic wall of the prostheses were analysed by SEM to assess the surface endothelium, histologically regarding tissue in#ammation, and by atomic absorption spectrophotometry to determine the content of tissue calcium. Results: There was no endothelium on control grafts, except for a short anastomotic pannus. The detoxi"ed group showed an incomplete patchy endothelium on the aortic wall but hardly any on the lea#ets, whereas, the in vitro lined group had aortic wall, sinuses and most of the lea#ets con#uently endothelialized. Tissue in#ammation was prominent in the control group and least expressed in the endothelialized group (p(0.05). Detoxi"cation signi"cantly reduced lea#et calci"cation. In the aortic wall, both detoxi"cation and endothelial lining were required to signi"cantly mitigate calci"cation. Conclusion: In the 12 week circulatory sheep model, the calcium mitigating e!ect of detoxi"cation was more pronounced than that of in vitro endothelialization. Nevertheless, there was a distinct overall bene"t if detoxi"cation was combined with endothelialization.
Ca2+ signaling in injured in situ endothelium of rat aorta
Cell Calcium, 2008
The inner wall of excised rat aorta was scraped by a microelectrode and Ca 2+ signals were investigated by fluorescence microscopy in endothelial cells (ECs) directly coupled with injured cells. The injury caused an immediate increase in the intracellular Ca 2+ concentration ([Ca 2+ ] i ), followed by a long-lasting decay phase due to Ca 2+ influx from extracellular space. The immediate response was mainly due to activation of purinergic receptors, as shown by the effect of P 2X and P 2Y receptors agonists and antagonists, such as suramin, ␣,-MeATP, MRS-2179 and 2-MeSAMP. Inhibition of store-operated Ca 2+ influx did not affect either the peak response or the decay phase. Furthermore, the latter was: (i) insensitive to phospholipase C inhibition, (ii) sensitive to the gap junction blockers, palmitoleic acid, heptanol, octanol and oleamide, and (iii) sensitive to La 3+ and Ni 2+ , but not to Gd 3+ . Finally, ethidium bromide or Lucifer Yellow did not enter ECs facing the scraped area.
Properties of cultured endothelium from adult human vessels
Arteriosclerosis, Thrombosis, and Vascular Biology, 1984
Endothelium was isolated from samples of aorta and vena cava obtained from cadaver donors at the time kidneys were harvested for transplantation. Digestion with collagenase and gentle swabbing were used to free the cells from the Intlmal surface. Low density seeding permitted isolation of individual colonies with typical endothellal morphology. Modified Medium 199 supplemented with 10%-20% human plasma-derived serum and an extract from the bovine hypothalamus (500 ^g/ml) enabled subcultured colonies to grow to confluency when culture surfaces were coated with fibronectin (1 /xg/cm 2 ). The presence of Factor VIII antigen was demonstrated using an indirect immunofluorescence technique. A monoclonal antibody to cultured umbilical vein endothelium, specific for endothelium, reacted with the subcultured cells from the aorta and vena cava. Type IV procollagen, flbronectln, and thrombospondln were identified as labeled proteins secreted by cultures of adult endothelium that had been Incubated with 3 H-prollne and 3 H-glycine. When the cultured endothelium was used In a sodlum-m-periodate stimulated T lymphocyte mltogenic culture system, the endothelium exhibited accessory cell function. Prostacyclln production stimulated by incubation with arachldonlc acid and PGH 2 was variable from vessel to vessel. However, average values were lower than normally seen with cultured primary umbilical vein endothelium. (Arteriosclerosis 4
Journal of Surgical Research, 2005
Objective. Evaluation of the pig and sheep models for biocompatibility investigations of vascular prostheses (VP). Design. Comparative analysis of animal experimental investigations involving two different animal models. Materials and methods. Commercially available polyester vascular prostheses (PET-VP) were implanted into two different animal models (infrarenal porcine aorta and ovine carotid artery). The costs, surgical handling, patency rate, and healing on the basis of macroscopic, microscopic, and immunohistochemical criteria were analyzed over a period of 3 months. Results. Handling and operating times (63 ؎ 10 versus 76 ؎ 16 min; P ؍ 0.125) did not differ significantly. The cost of the two animal models was comparable. Integration of the VP was complete in the sheep model, but varied in the pig model (two complete, four incomplete). Complete endothelialization of all VPs was observed in the pig, which contrasted with the sheep with complete (circular) endothelialization only in the region of the anastomosis. The thickness of neointima in the region of the anastomosis differed insignificantly; immunohistochemically, only periprosthetic Ki67 was significantly reduced (28.7 ؎ 9.9 versus 6 ؎ 0.9%; P ؍ 0.002) in the sheep. Conclusions. In the porcine model, extremely good endothelialization of the VP was observed, with formation of a rapid neointimal hyperplasia. The ovine model was characterized by the fact that postopera-tive follow-up investigations were easy to perform. Complete endothelialization was not observed.
Recovery of endothelial cells and prostanoid production in endothelial cell-seeded grafts
European Journal of Vascular and Endovascular Surgery, 1996
Objective: To investigate the function and morphology of endothelial ceil (EC) seeded grafts. Design: Experimental open study. Chief outcome measures: Endoluminal release of prostacyclin (6-Keto-PGFI~) and thromboxane B2 (TxB2), patency, EC coverage and cell identity. Materials: In 12 sheep, segments of both carotid arteries were excised. On one side a seeded and on the other an unseeded dacron graft were inserted. After 3 months the grafts were excised, hz grafts and arteries, the endoluminal release of 6-keto-PGFla and TxB2 was determined in a perfusion system. Scanning electron microscopy (SEM) and light microscopy were used to determine the EC coverage and cell identity. Results: Eight animals survived. Three seeded and two unseeded grafts were occluded. Prostacyclin release did not differ significantly between seeded and unseeded grafts and arteries, when the arteries were looked upon as one group. When the graft was compared with its corresponding artery, i.e. the artery it replaced, a significantly lower release was found in the unseeded group. Thromboxane release was undetectable in arteries but significantly higher in both graft groups. SEM revealed a cellular coverage of 75% in the seeded grafts and 50% in the unseeded (not significant). Light microscopy showed a patchy staining for Factor VIII-related antigen in some grafts in both groups. Conclusion: Prostacyclin release in unseeded and seeded dacron grafts did not differ 3 months after implantation in sheep, except when the ~raft was compared with its corresponding artery. The significance of this remains to be settled. Seeded grafts did not have a higher proportion of endothelial coverage than unseeded grafts.
Spontaneous host endothelial growth on bioprostheses. Influence of fixation
PubMed, 1992
Background: Neither homografts nor bioprostheses have previously been seen to acquire a host endothelium. We previously reported a direct relation between aldehyde tanning and bioprosthesis calcification and the absence of calcification in the absence of aldehyde. Methods and results: Bovine pericardium was 1) treated with 0.625% glutaraldehyde and stored in 4% formaldehyde, 2) treated with 99.5% glycerol, and 3) treated with 99.5% glycerol and stored in formaldehyde (0.25-4%). The treated pericardium was used to construct stentless mitral valve prostheses (of a single pattern) that were implanted in weanling sheep. After the animals were killed, a strip of anterior cusp from annulus to papillary muscle was processed and examined by scanning electron microscopy for the presence of host endothelial growth. Avoidance of aldehyde allowed host endothelial growth in all cases (six of six), and pure aldehyde treatment inhibited growth in five of six animals. Exposure to aldehyde after glycerol treatment interfered with endothelialization significantly; after longer periods of implantation, however, endothelial growth occurred almost invariably in this group (12 of 13 implanted longer than 200 days). For this group, there was a statistically significant difference for duration of implantation between the valves that grew endothelium and those that did not (218.4 +/- 61.9 versus 128.5 +/- 65.4 days). Conclusions: Aldehyde treatment inhibits endothelial growth. With glycerol treatment, growth is uniformly present. Limited exposure to aldehydes after glycerol treatment inhibits endothelial growth, but this effect was ameliorated by prolonged implantation. The possibility of host endothelium-covered, noncalcifying bioprostheses is now real.
Journal of Surgical Research, 1979
Localization of Factor VIII-related antigen by indirect immunofluorescent microscopy reliably identifies endothelium in frozen sections of canine blood vessels, including vasa vasorum. Using this technique, endothelium was found to line 6-cm-long porous Dacron arterial grafts in place in dogs for 6 months and 1 year. Grafts seeded with autogenous, venous endothelial cells at implantation showed specific fluorescence in the midportions of their flow surfaces after I month. Unseeded grafts were devoid of specific fluorescence beyond the region of pannus ingrowth. Vasa vasorum were very well delineated, even when no more than a row of single cells. We conclude that localization of Factor VIII-related antigen reliably identifies true endothelium in vascular grafts and will be useful in the study of vascular prosthetic healing.