scholarly journals On the interaction of rabbit antithrombin III with the luminal surface of the normal and deendothelialized rabbit thoracic aorta in vitro

Blood ◽  
1986 ◽  
Vol 67 (4) ◽  
pp. 878-886 ◽  
Author(s):  
MW Hatton ◽  
SL Moar ◽  
M Richardson
Keyword(s):  
Thoracic Aorta ◽  
Antithrombin Iii ◽  
Balloon Catheter ◽  
Rabbit Aorta ◽  
Luminal Surface ◽  
High Affinity ◽  
Antithrombin Activity ◽  
Thrombin Antithrombin Iii Complex

Abstract Pure rabbit antithrombin III was isotope labeled (with 125I or 3H) by two different methods; neither procedure caused a loss of antithrombin activity although both methods affected the affinity of the protein for Sepharose-heparin. From segments from freshly excised rabbit aorta, the uptake of isotope-labeled antithrombin III by the endothelium was rapid and saturable, although relatively small compared to the uptake of thrombin; binding of 3H-antithrombin III to the endothelium resembled that of 125I-antithrombin III. Transendothelial passage of antithrombin III into the subendothelial layers (intima-media) was slow and progressive. Endothelium binding was not affected by pretreating the vessel with either heparin, thrombin, or glycosaminoglycan-specific enzymes. Endothelium-bound antithrombin III was not selectively displaced by either heparin or thrombin. In contrast, endothelium-bound thrombin was rapidly dislodged by antithrombin III as a thrombin- antithrombin III complex. The surface of the deendothelialized aorta (ie, subjected to a balloon catheter) bound antithrombin III avidly. Pretreatment of the deendothelialized vessel with glycosaminoglycan- specific enzymes, particularly heparitinase, decreased intima-media binding by up to 80%. 125I-antithrombin III, when bound to the deendothelialized vessel surface, was actively displaced by either heparin, thrombin, or by unlabeled antithrombin III. The relatively poor binding of antithrombin III compared with that of thrombin by the endothelium in vitro supports an earlier proposal (Lollar P, Owen WG: J Clin Invest 66:1222–1230, 1980) that thrombin bound to high-affinity sites, possibly pericellular proteoglycan, of the endothelium is inactivated by plasma antithrombin III in vivo. Such a situation probably holds for large arteries at least.

scholarly journals On the interaction of rabbit antithrombin III with the luminal surface of the normal and deendothelialized rabbit thoracic aorta in vitro

Blood ◽  
1986 ◽  
Vol 67 (4) ◽  
pp. 878-886
Author(s):  
MW Hatton ◽  
SL Moar ◽  
M Richardson
Keyword(s):  
Thoracic Aorta ◽  
Antithrombin Iii ◽  
Balloon Catheter ◽  
Rabbit Aorta ◽  
Luminal Surface ◽  
High Affinity ◽  
Antithrombin Activity ◽  
Thrombin Antithrombin Iii Complex

Pure rabbit antithrombin III was isotope labeled (with 125I or 3H) by two different methods; neither procedure caused a loss of antithrombin activity although both methods affected the affinity of the protein for Sepharose-heparin. From segments from freshly excised rabbit aorta, the uptake of isotope-labeled antithrombin III by the endothelium was rapid and saturable, although relatively small compared to the uptake of thrombin; binding of 3H-antithrombin III to the endothelium resembled that of 125I-antithrombin III. Transendothelial passage of antithrombin III into the subendothelial layers (intima-media) was slow and progressive. Endothelium binding was not affected by pretreating the vessel with either heparin, thrombin, or glycosaminoglycan-specific enzymes. Endothelium-bound antithrombin III was not selectively displaced by either heparin or thrombin. In contrast, endothelium-bound thrombin was rapidly dislodged by antithrombin III as a thrombin- antithrombin III complex. The surface of the deendothelialized aorta (ie, subjected to a balloon catheter) bound antithrombin III avidly. Pretreatment of the deendothelialized vessel with glycosaminoglycan- specific enzymes, particularly heparitinase, decreased intima-media binding by up to 80%. 125I-antithrombin III, when bound to the deendothelialized vessel surface, was actively displaced by either heparin, thrombin, or by unlabeled antithrombin III. The relatively poor binding of antithrombin III compared with that of thrombin by the endothelium in vitro supports an earlier proposal (Lollar P, Owen WG: J Clin Invest 66:1222–1230, 1980) that thrombin bound to high-affinity sites, possibly pericellular proteoglycan, of the endothelium is inactivated by plasma antithrombin III in vivo. Such a situation probably holds for large arteries at least.

scholarly journals Behavior of plasminogen at the luminal surface of the normal and deendothelialized rabbit aorta in vivo and in vitro

Blood ◽  
1988 ◽  
Vol 71 (5) ◽  
pp. 1260-1267 ◽  
Author(s):  
MW Hatton ◽  
SL Moar ◽  
M Richardson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Balloon Catheter ◽  
Rabbit Aorta ◽  
Luminal Surface ◽  
Plasmin Activity ◽  
Transmission Electron ◽  
Rapid Adsorption

Abstract The behavior of purified rabbit plasminogen at the luminal surface of the uninjured and deendothelialized rabbit aorta has been studied in vivo and in vitro. After intravenous injection, 125I-plasminogen associated rapidly with the endothelium (approximately 0.1 pmol/cm2 at saturation) and passed through to accumulate in the subendothelium. At two to 15 hours after injection, 11 to 15 times more radioactivity was associated with the subendothelium than with the endothelium. Removal of the endothelium by balloon catheter led to a rapid adsorption of 125I-plasminogen by the luminal surface of the vessel; saturation (9.1 pmol/cm2) was attained at ten to 20 minutes after deendothelialization. Of the adsorbed plasminogen (radioactivity), only 2% to 4% was associated with the adherent platelet monolayer. Uptake of 125I- plasminogen by the deendothelialized vessel was not significantly inhibited by epsilon-aminohexanoic acid whether injected before or after the 125I-plasminogen. No evidence of plasmin activity at the aorta surface was found from either transmission electron microscopy studies or from amidolytic assays of plasminogen-saturated deendothelialized aorta samples before or after urokinase treatment. Balloon catheter treatment in vivo, however, generated significant antiplasmin activity of the deendothelialized aorta surface. We conclude that plasmin formed in vivo is probably inactivated by the antiplasmin activity that is associated with the subendothelium.

scholarly journals Behavior of plasminogen at the luminal surface of the normal and deendothelialized rabbit aorta in vivo and in vitro

Blood ◽  
1988 ◽  
Vol 71 (5) ◽  
pp. 1260-1267
Author(s):  
MW Hatton ◽  
SL Moar ◽  
M Richardson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Balloon Catheter ◽  
Rabbit Aorta ◽  
Luminal Surface ◽  
Plasmin Activity ◽  
Transmission Electron ◽  
Rapid Adsorption

The behavior of purified rabbit plasminogen at the luminal surface of the uninjured and deendothelialized rabbit aorta has been studied in vivo and in vitro. After intravenous injection, 125I-plasminogen associated rapidly with the endothelium (approximately 0.1 pmol/cm2 at saturation) and passed through to accumulate in the subendothelium. At two to 15 hours after injection, 11 to 15 times more radioactivity was associated with the subendothelium than with the endothelium. Removal of the endothelium by balloon catheter led to a rapid adsorption of 125I-plasminogen by the luminal surface of the vessel; saturation (9.1 pmol/cm2) was attained at ten to 20 minutes after deendothelialization. Of the adsorbed plasminogen (radioactivity), only 2% to 4% was associated with the adherent platelet monolayer. Uptake of 125I- plasminogen by the deendothelialized vessel was not significantly inhibited by epsilon-aminohexanoic acid whether injected before or after the 125I-plasminogen. No evidence of plasmin activity at the aorta surface was found from either transmission electron microscopy studies or from amidolytic assays of plasminogen-saturated deendothelialized aorta samples before or after urokinase treatment. Balloon catheter treatment in vivo, however, generated significant antiplasmin activity of the deendothelialized aorta surface. We conclude that plasmin formed in vivo is probably inactivated by the antiplasmin activity that is associated with the subendothelium.

Effects of Heparin Oligosaccharides with High Affinity for Antithrombin III in Experimental Venous Thrombosis

1982 ◽  
Vol 47 (03) ◽  
pp. 244-248 ◽  
Author(s):  
D P Thomas ◽  
Rosemary E Merton ◽  
T W Barrowcliffe ◽  
L Thunberg ◽  
U Lindahl
Keyword(s):  
Antithrombin Iii ◽  
Specific Activity ◽  
High Specific Activity ◽  
Factor Xa ◽  
Blood Levels ◽  
Thrombin Time ◽  
High Affinity ◽  
Very High

SummaryThe in vitro and in vivo characteristics of two oligosaccharide heparin fragments have been compared to those of unfractionated mucosal heparin. A decasaccharide fragment had essentially no activity by APTT or calcium thrombin time assays in vitro, but possessed very high specific activity by anti-Factor Xa assays. When injected into rabbits at doses of up to 80 ¼g/kg, this fragment was relatively ineffective in impairing stasis thrombosis despite producing high blood levels by anti-Xa assays. A 16-18 monosaccharide fragment had even higher specific activity (almost 2000 iu/mg) by chromogenic substrate anti-Xa assay, with minimal activity by APTT. When injected in vivo, this fragment gave low blood levels by APTT, very high anti-Xa levels, and was more effective in preventing thrombosis than the decasaccharide fragment. However, in comparison with unfractionated heparin, the 16-18 monosaccharide fragment was only partially effective in preventing thrombosis, despite producing much higher blood levels by anti-Xa assays.It is concluded that the high-affinity binding of a heparin fragment to antithrombin III does not by itself impair venous thrombogenesis, and that the anti-Factor Xa activity of heparin is only a partial expression of its therapeutic potential.

Thrombogenicity of the Injured Vessel Wall – Role of Antithrombin and Heparin

1994 ◽  
Vol 71 (01) ◽  
pp. 147-153 ◽  
Author(s):  
Siw Frebelius ◽  
Ulf Hedin ◽  
Jesper Swedenborg
Keyword(s):  
Vessel Wall ◽  
Antithrombin Iii ◽  
Rabbit Aorta ◽  
Continuous Treatment ◽  
Balloon Injury ◽  
Coagulant Activity ◽  
Risk For Thrombosis ◽  
Inhibition Of Thrombin

SummaryThe thrombogenicity of the vessel wall after endothelial denudation is partly explained by an impaired inhibition of thrombin on the subendothelium. We have previously reported that thrombin coagulant activity can be detected on the vessel wall after balloon injury in vivo. The glycosaminoglycans of the subendothelium differ from those of the endothelium and have a lower catalyzing effect on antithrombin III, but inhibition of thrombin can still be augmented by addition of antithrombin III to the injured vessel surface.In this study the effect of antithrombin III and heparin on thrombin coagulant activity on the vessel wall was studied after in vivo balloon injury of the rabbit aorta using biochemical and immunohistochemical methods and thrombin was analysed after excision of the vessel. Continuous treatment with heparin, lasting until sacrifice of the animal, or treatment with antithrombin III resulted in significant reduction of thrombin coagulant activity on the injured aorta. Heparin given only in conjunction with the injury did not prevent thrombin coagulant activity or deposition of fibrin on the surface.The capacity of the injured vessel wall to inhibit thrombin in vitro was improved on aortic segments obtained from animals receiving antithrombin III but not from those given heparin. It is concluded that treatment with antithrombin III interferes with thrombin appearance on the vessel wall after injury and thereby reduces the risk for thrombosis.

Quantitation of Platelet Adherence to Rabbit Aortae and Platelet Survival After two Injuries with a Balloon Catheter

1979 ◽  
Author(s):  
R.L. Kinlough-Rathbone ◽  
H.M. Groves ◽  
S. Maric ◽  
M.A. Packham ◽  
J.F. Mustard
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cell ◽  
Muscle Cell ◽  
Balloon Catheter ◽  
Rabbit Aorta ◽  
Platelet Adherence ◽  
Platelet Survival ◽  
Single Balloon

Following a single balloon catheter injury to a rabbit aorta (INJ 1) a monolayer of platelets covers the subendothelium within 10 min, the surface becomes relatively non-reactive to further platelet accumulation and platelet survival is not altered. We have now studied whether a second similar injury (INJ 2) of the non-reactive, smooth muscle cell-rich neointima 7 days after INJ 1 makes the surface of the neointima reactive to platelets or alters platelet survival. 51Cr-platelet adherence to the neointima of aortae subjected to INJ 2 in vitro 7 days after an initial in vivo injury was not significantly different from the adherence following a single in vitro injury (16,600 ± 3100 platelets/mm2 and 27,600 ± 4000 respectively, ρ > 0.2). In vivo adherence of 51Cr-platelets to the surface of rabbit aortae was similar following INJ 1 (0.084 ± 0.009% of the circulate, platelets) and INJ 2 (0.130 ± 0.03%, p > 0.2). Platelet survival after injury to the neointima was not significantly different in animals with an undamaged aortic endothelium (74.6 ± 5.9 hr and 80.2 ± 4.3 hr respectively, ρ > 0.5). Thus, a second injury involving the smooth’ muscle cell-rich neointima that forms after removal of the endothelium with a balloon catheter does not cause more platelets to accumulate than the initial injury, nor shorten platelet survival.

Quantitation of Platelet Adherence to Rabbit Aortae and Platelet Survival After Two Injuries With a Balloon Catheter

1979 ◽  
Author(s):  
R Kinlough-Rathbone ◽  
H Groves ◽  
S Maric ◽  
M Packham ◽  
J Mustard
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cell ◽  
Muscle Cell ◽  
Balloon Catheter ◽  
Rabbit Aorta ◽  
Platelet Adherence ◽  
Platelet Survival ◽  
Single Balloon

Following a single balloon catheter injury to a rabbit aorta (INJ 1) a monolayer of platelets covers the subendothelium within 10 min, the surface becomes relatively nonreactive to further platelet accumulation and platelet survival is not altered. We have now studied whether a second similar injury (INJ 2) of the non-reactive, smooth muscle cell-rich neointima 7 days after INJ 1 makes the surface of the neointima reactive to platelets or alters platelet survival. 51Cr-platelet adherence to the neointima of aortae subjected to INJ 2 in vitro 7 days after an initial in vivo injury was not significantly different from the adherence following a single in vitro injury (16,600 ± 3100 platelets/mm2 and 27,600 ± 4000 respectively, p > 0.2). In vivo adherence of 51Cr-platelets to the surface of rabbit aortae was similar following INJ 1 (0.084 ± 0.009% of the circulating platelets) and INJ 2 (0.130 ± 0.03%, p > 0.2). Platelet survival after injury to the neointima was not significantly different in animals with an undamaged aortic endothelium (74.6 ±5.9 hr and 80.2 ± 4.3 hr respectively, p > 0.5). Thus, a second injury involving the smooth muscle cell-rich neointima that forms after removal of the endothelium with a balloon catheter does not cause more platelets to accumulate than the initial injury, nor shorten platelet survival.

THE BEHAVIOUR OF RABBIT PLASMINOGEN AT THE LUMINAL SURFACE OF RABBIT AORTA IN VIVO BEFORE AND AFTER BALLOON-CATHETER INJURY

1987 ◽  
Author(s):  
Mark W C Hatton ◽  
Susan Moar ◽  
Mary Richardson
Keyword(s):  
White Male ◽  
Balloon Catheter ◽  
Rabbit Aorta ◽  
Ruthenium Red ◽  
Transmission Electron ◽  
Before And After ◽  
Ruthenium Red Staining ◽  
Balloon Catheter Injury

A previous study from this laboratory has identified the susceptibility of the de-endothelialised aorta, particularly the proteoglycan (PG) components of the extracellular matrix (ECM), to proteolytic damage if exposed to plasmin in vitro. To explore the possiblity that this occurs in vivo, a possible association between 125I-plasminogen (PLG) binding to the arterial wall, its activation to plasmin (PLN) and, subsequently, proteolytic damage to the intimal ECM has been studied. Intravenous injection of 125I-PLG in healthy N.Z. white male rabbits showed that PLG associated minimally (<0.01% of circulating PLG/cm2 /ml blood at 1 h) with the thoracic aorta endothelium, measured after Hautchen preparation from 1-cm vessel segments. Trans endothelial passage, measured as 125I-PLG associated with thg subendothelium (intima-media), progressed to 0.015%/cm2 /ml blood at 1 h. In contrast, the process of de-endothelialisation by balloon catheter led to a rapid uptake of bI-PLG by the denuded vessel surface. At saturation (approx. 10 min after injury), 0.7 - 0.8% of circulating PLG/cm2/ml blood was adsorbed by the entire de-endothelialised intima-media: Of the adsorbed PLG, 2-3% was associated with the platelet layer. Uptake was not inhibited by eACA (dose: 200 mg/kg) given i.v. before I-PLG. Adsorbed PLG was not released significantly from segments incubated in MEM containing 4% (w/v) RSA in vitro PLN activity was not detected. Furthermore, assessment of the ECM by transmission electron microscopy, after ruthenium red staining, showed that uptake of PLG by the de-endothelialised vessel in vivo was not associated with obvious damage to the PG components. Supported by the Heart and Stroke Foundation of Ontario.

Catheter-Implanted Prosthetic Heart Valves

1993 ◽  
Vol 16 (5) ◽  
pp. 253-262 ◽  
Author(s):  
L.L. Knudsen ◽  
H.R. Andersen ◽  
J.M. Hasenkam
Keyword(s):  
Thoracic Aorta ◽  
Mechanical Stability ◽  
Balloon Catheter ◽  
Artificial Heart Valve ◽  
Prosthetic Heart Valves ◽  
Descending Thoracic Aorta ◽  
Catheter Technique ◽  
Valve Function

A new expandable artificial heart valve was developed for implantation by a transluminal catheter technique without using thoracotomy or extracorporeal circulation. The aim of this study was to implant the valve in isolated vessels of the descending thoracic aorta as well as in closed chest pigs, and furthermore to study the prosthesis’ mechanical stability and the valve function. The artificial valve was made by mounting a porcine aortic valve on an expandable stent. Before implantation, the stent-valve was compressed on a deflated balloon catheter and mounted inside an introducer sheath. After intravascular introduction to the descending thoracic aorta the stent-valve was discharged from the sheath. Implantation was performed by balloon inflation which expanded the stent-valve to a diameter exceeding the internal vessel's diameter. After balloon deflation the stent-valve maintained an expanded configuration ensuring a stable fixation against the vessel wall. In vitro implantations were performed in 36 isolated descending thoracic aorta specimens obtained from 80 kg pigs. Mechanical stability was evaluated by applying a downing load to the prosthesis. No displacement occurred at loads ≤ 1 kg when a large balloon (31 mm) was used for implantation. Transvalvular pressure differences between 11-47 mmHg (median) were obtained at antegrade flowrates between 5-8 1/min. Furthermore, only moderate leakage flows were measured during retrograde perfusion. In vivo implantations were performed in six 80 kg pigs. Implantation was safe and easy, and angiograph and haemodynamic evaluations revealed essentially no stenosis or regurgitation. No complications in migration, perforation, hemorrhage or thrombosis were observed. This study indicates a good mechanical stability and valve function of the new expandable artificial valves.

Sign in / Sign up

Export Citation Format

Share Document