Defective Platelet Adhesion and Aggregation on Subendothelium Exposed in Vivo or in Vitro to Flowing Blood of Fawn-Hooded Rats with Storage Pool Disease

1977 ◽  
Vol 38 (03) ◽  
pp. 0620-0629 ◽  
Author(s):  
Th. B Tschopp ◽  
H. R Baumgartner

SummaryCitrated rat blood was exposed to either subendothelium or the fibrillar collagen of enzymatically modified subendothelium of rabbit aorta in a perfusion system under laminar blood flow conditions at a wall shear rate of 830 s−1. The resulting platelet surface interaction was estimated by a morphometric method.With blood of fawn-hooded (FH) rats, which suffer from hereditary platelet “storage pool disease”, platelet spreading was slower on both exposed surfaces and resulted in a lower rate of surface coverage with platelets on subendothelium if compared with controls.The rate of adhesion of FH-platelets to the fibrillar collagen, however, was slightly higher as compared to controls despite reduced platelet spreading. This was probably due to the absence of platelet thrombus formation observed with FH-rat blood, whereas massive platelet thrombus formation took place in the controls. It is suggested that platelets of controls which arrive near the surface are preferentially incorporated into the rapidly forming platelet thrombi rather than reaching the surface, and hence do not increase surface-coverage with adhering platelets.The defective platelet adhesion and aggregation in the FH-rat was also apparent after desendothelialization of the aorta in vivo, although to a lesser extent, probably due to the extremely low thrombogenicity of rat aorta subendothelium.

2006 ◽  
Vol 290 (4) ◽  
pp. H1671-H1679 ◽  
Author(s):  
Rolando E. Rumbaut ◽  
Ricardo V. Bellera ◽  
Jaspreet K. Randhawa ◽  
Corie N. Shrimpton ◽  
Swapan K. Dasgupta ◽  
...  

Endotoxemia promotes adhesive interactions between platelets and microvascular endothelium in vivo. We sought to determine whether endotoxin (lipopolysaccharide, LPS) modified platelet thrombus formation in mouse cremaster venules and whether Toll-like receptor 4 (TLR4) and neutrophils were involved in the response. Intravital videomicroscopy was performed in the cremaster microcirculation of pentobarbital-anesthetized mice; venular platelet thrombi were induced with a light/dye endothelial injury model. C57BL/6 mice treated with Escherichia coli endotoxin had enhanced rates of venular platelet thrombus formation: the time to microvessel occlusion was reduced by ∼50% ( P < 0.005) compared with saline-treated animals. Enhanced microvascular thrombosis was evident as early as 2 h after LPS administration. LPS had no effect on thrombosis in either of two mouse strains with altered TLR4 signaling (C57BL/10ScNJ or C3H/HeJ), whereas it enhanced thrombosis in the control strains (C57BL/10J and C3H/HeN). LPS also enhanced platelet adhesion to endothelium in the absence of light/dye injury. Platelet adhesion, but not enhanced thrombosis, was inhibited by depletion of circulating neutrophils. LPS failed to enhance platelet aggregation ex vivo and did not influence platelet P-selectin expression, a marker of platelet activation. These findings support the notion that endotoxemia promotes platelet thrombus formation independent of neutrophils and without enhancement of platelet aggregation, via a TLR4-dependent mechanism.


1987 ◽  
Author(s):  
E Bastida ◽  
G Escolar ◽  
R Castillo ◽  
A Ordinas ◽  
J J Sixma

Fibronectin (FN) plays a role in several adhesion mediated functions including the interaction of platelets with subendothelium.We investigated the role of plasma FN in platelet adhesion and platelet thrombus formation under flow conditions.To do this we used two different perfusion models:1)the annular chamber with α -chymotrypsin-treated rabbit vessel segments and 2)the flat chamber with coverslips coated with fibrillar purified human collagen type III.Perfusates consisted of washed platelets, and washed red blood celIs,suspended in normal or FN-depleted plasma.Perfusions were carried out for 10 min at shear rates of 300 or 1300 sec™1 Platelet deposition and thrombus dimensions were morphometrically evaluated by a computerized system. We found that depletion of plasma FN significantly reduced the percentage of total coverage surface and percentage of platelet thrombus, at both shear rates studied, and in both perfusion systems (p < 0.01)(p < 0.01).The dimensions of the platelet thrombi formed in perfusions at high shear rate were also significantly reduced in perfusions carried out with FN-depleted plasma.(p < 0.01). Addition of purified FN to FN-depleted perfusates restored all the values to those measured in the control perfusions.These results indicate that, in addition to supporting platelet adhesion to the subendothelium and to fibrillar collagen, FN contributes to platelet thrombus formation under flow conditions.


1976 ◽  
Vol 35 (01) ◽  
pp. 124-138 ◽  
Author(s):  
Hans R Baumgartner ◽  
Reto Muggli ◽  
Thomas B Tschopp ◽  
Vincent T Turitto

SummaryPlatelet adhesion to natural and artificial surfaces and adhesion-induced aggregation were investigated in vitro using an annular perfusion chamber. The surfaces were exposed to anticoagulated blood under identical flow conditions (~ arterial shear rates). The initial attachment of platelets (contact) appeared less surface specific than spreading and release. Fibrillar collagen was the most powerful inducer of platelet degranulation whereas elastin, microfibrils and epon were virtually inactive. Fibrillar collagen caused release also in the absence of spreading. Surface coverage with platelets did not exceed 25 % unless spreading occurred. Perfusion with platelet-free plasma or platelet-poor blood did not remove adhering platelets. However, platelets were translocated from mural thrombi to the surface by such perfusion. In addition, platelets which detached from mural thrombi adhered more readily to elastin or microfibrils than platelets from the circulating blood. The initial attachment of platelets to subendothelium was inhibited in von Willebrand’s disease, the Bernard-Soulier syndrome and at high concentrations of dipyridamole; spreading was inhibited in storage pool disease of rats, at low temperature (20° C), with EDTA (3 mM) and Prostaglandin E1 (1 μM); and adhesion-induced aggregation was inhibited in thrombasthenia, storage pool disease and after ingestion of sulfinpyrazone or Aspirin.It is concluded that the initial attachment (contact) of platelets, spreading and surface-induced release of platelet constituents are at least partially independent phenomena, the latter two being highly surface specific. At flow conditions which cause the disappearance of platelet thrombi, platelet adhesion appears as an irreversible process.


1977 ◽  
Vol 37 (01) ◽  
pp. 017-028 ◽  
Author(s):  
Hans R. Baumgartner ◽  
Thomas B. Tschopp ◽  
Harvey J. Weiss

SummaryAnticoagulated whole blood from patients and control subjects was circulated through an annular perfusion chamber in which the fibrillar collagen of α chymotrypsin-digested subendothelium and intact subendothelium were exposed. The blood flow conditions corresponded to those in arteries (830 sec–1 wall shear rate). Platelet surface interaction was measured mor-phometrically.Decreased adhesion to fibrillar collagen associated with normal spreading and normal adhesion-induced formation of platelet thrombi was found with blood of patients with von Willebrand’s disease and the Bernard Soulier Syndrome, indicating a defect in the initial attachment reaction of platelets with collagen. Platelets of patients with thrombasthenia did normally adhere to the collagen fibrils and also lost their subcellular organelles during this reaction, but they totally failed to adhere to each other. In storage pool disease platelet thrombus formation was consistently inhibited whereas adhesion and spreading was inhibited in some patients and normal in others. In contrast adhesion was always normal after ingestion of aspirin which consistently caused a marked inhibition of platelet thrombi. These findings correspond – in essence – to those previously described on intact subendothelium. However, the observed defects are more pronounced on the fibrillar collagen than on intact subendothelium.


1991 ◽  
Vol 65 (02) ◽  
pp. 202-205 ◽  
Author(s):  
Harvey J Weiss ◽  
Vincet T Turitto ◽  
Hans R Baumgartner

SummaryIn order to explore further the mechanism by which glycoprotein GPIIb-IIIa promotes platelet vessel wall interaction, platelet adhesion to subendothelium was studied in an annular chamber in which subendothelium from rabbit aorta was exposed at a shear rate of 2,600 s−1 to blood from patients with thrombasthenia. Perfusions were conducted for each of 5 exposure times (1 ,2,3, 5 and 10 min), and the percent surface coverage of the vessel segment with platelets in the contact (C) and spread (S) stage was determined. Increased values of platelet contact (C) were obtained in thrombasthenia at all exposure times; this finding is consistent with a defect in platelet spreadirg, based on a previously described kinetic model of platelet attachment to subendothelium. According to this model of attachment, increased values of platelet contact (C) at a single exposure time may be indicative of either a defect in spreading (S) or initial contact (C), but multiple exposures will result in increased contact only for defects which are related to defectiye platelet spreading (s).The results obtained over a broad range of exposure times provide more conclusive evidence that GPIIb-IIIa mediates platelet spreading than those previously obtained at single exposure times.


1967 ◽  
Vol 18 (03/04) ◽  
pp. 592-604 ◽  
Author(s):  
H. R Baumgartner ◽  
J. P Tranzer ◽  
A Studer

SummaryElectron microscopic and histologic examination of rabbit ear vein segments 4 and 30 min after slight endothelial damage have yielded the following findings :1. Platelets do not adhere to damaged endothelial cells.2. If the vessel wall is denuded of the whole endothelial cell, platelets adhere to the intimai basement lamina as do endothelial cells.3. The distance between adherent platelets as well as endothelial cells and intimai basement lamina measures 10 to 20 mµ, whereas the distance between aggregated platelets is 30 to 60 mµ.4. 5-hydroxytryptamine (5-HT) is released from platelets during viscous metamorphosis at least in part as 5-HT organelles.It should be noted that the presence of collagen fibers is not necessary for platelet thrombus formation in vivo.


1979 ◽  
Vol 42 (02) ◽  
pp. 603-610 ◽  
Author(s):  
J H Adams ◽  
J R A Mitchell

SummaryThe ability of potential anti-thrombotic agents to modify platelet-thrombus formation in injured cerebral arteries in the rabbit was tested. Low doses of heparin were without effect, while higher doses produced variable suppression of white body formation but at the expense of bleeding. Aspirin did not inhibit white body formation but another non-steroid anti-inflammatory agent, flurbiprofen was able to do so, as was the anti-gout agent, sulphinpyrazone. Magnesium salts both topically and parenterally, suppressed thrombus formation and increased the concentration of ADP which was required to initiate thrombus production at minor injury sites.


2003 ◽  
Vol 197 (11) ◽  
pp. 1585-1598 ◽  
Author(s):  
Shahrokh Falati ◽  
Qingde Liu ◽  
Peter Gross ◽  
Glenn Merrill-Skoloff ◽  
Janet Chou ◽  
...  

Using a laser-induced endothelial injury model, we examined thrombus formation in the microcirculation of wild-type and genetically altered mice by real-time in vivo microscopy to analyze this complex physiologic process in a system that includes the vessel wall, the presence of flowing blood, and the absence of anticoagulants. We observe P-selectin expression, tissue factor accumulation, and fibrin generation after platelet localization in the developing thrombus in arterioles of wild-type mice. However, mice lacking P-selectin glycoprotein ligand 1 (PSGL-1) or P-selectin, or wild-type mice infused with blocking P-selectin antibodies, developed platelet thrombi containing minimal tissue factor and fibrin. To explore the delivery of tissue factor into a developing thrombus, we identified monocyte-derived microparticles in human platelet–poor plasma that express tissue factor, PSGL-1, and CD14. Fluorescently labeled mouse microparticles infused into a recipient mouse localized within the developing thrombus, indicating that one pathway for the initiation of blood coagulation in vivo involves the accumulation of tissue factor– and PSGL-1–containing microparticles in the platelet thrombus expressing P-selectin. These monocyte-derived microparticles bind to activated platelets in an interaction mediated by platelet P-selectin and microparticle PSGL-1. We propose that PSGL-1 plays a role in blood coagulation in addition to its known role in leukocyte trafficking.


1981 ◽  
Author(s):  
Y C Chen ◽  
K K Wu ◽  
E R Hall ◽  
D L Venton ◽  
G C Le Breton

It is well recognized that thromboxane A2(TXA2) plays an important role in platelet reactivity. To determine the role of TXA2 in platelet-vessel wall (P-V) interaction, the effect of 1-benzylimidazole (1-BI), a specific inhibitor of thromboxane synthetase, and 13-azaprostanoic acid (APA), a TXA2 antagonist, on platelet thrombus formation was evaluated in vivo in NZW male rabbits using the autologous indium-111 (111In) labeled platelet technique. Rabbits were treated with intravenous 1-BI or APA or vehicles. After injection of autologous 111In-platelets, de-endothelialization of the abdominal aorta was created by a balloon catheter technique. At 3 hrs, blood samples were obtained and the animals were sacrificed. The aortae were removed and the injured and uninjured segments were dissected. Radioactivity counts and dry weight of the tissues and blood were determined. The vascular radioactivity counts were converted to platelet numbers by using a standard linear calibration curve. As small numbers of platelets adhered to normal vessel wall nonspecifically, this number was subtracted to obtain specific platelet accumulation at the injured sites. 1-BI at 10mg/kg reduced the specific platelet accumulation significantly (n=5, 12.3±S.D.I.5×106 pl/gm tissue; p<0.01) when compared with the controls (n=10, 33.0±5.1×106 pl/gm tissue). Platelet accumulation was further reduced by increasing the dosage to 30mg/kg. By contrast, APA injection (10mg/kg) had no significant effect. However, when APA was given by constant infusion at 250μg/kg/min 1 hr prior to injury, the APA-treated animals had an 80% reduction of platelet accumulation relative to controls. These findings indicate that TXA2 plays an important role in P-V interaction and specific inhibition of TXA2 appears to be efficacious in eliminating platelet thrombus formation.


Sign in / Sign up

Export Citation Format

Share Document