Computational investigation of blood cell transport in retinal microaneurysms

Microaneurysms (MAs) are one of the earliest clinically visible signs of diabetic retinopathy (DR). MA leakage or rupture may precipitate local pathology in the surrounding neural retina that impacts visual function. Thrombosis in MAs may affect their turnover time, an indicator associated with visual and anatomic outcomes in the diabetic eyes. In this work, we perform computational modeling of blood flow in microchannels containing various MAs to investigate the pathologies of MAs in DR. The particle-based model employed in this study can explicitly represent red blood cells (RBCs) and platelets as well as their interaction in the blood flow, a process that is very difficult to observe in vivo. Our simulations illustrate that while the main blood flow from the parent vessels can perfuse the entire lumen of MAs with small body-to-neck ratio (BNR), it can only perfuse part of the lumen in MAs with large BNR, particularly at a low hematocrit level, leading to possible hypoxic conditions inside MAs. We also quantify the impacts of the size of MAs, blood flow velocity, hematocrit and RBC stiffness and adhesion on the likelihood of platelets entering MAs as well as their residence time inside, two factors that are thought to be associated with thrombus formation in MAs. Our results show that enlarged MA size, increased blood velocity and hematocrit in the parent vessel of MAs as well as the RBC-RBC adhesion promote the migration of platelets into MAs and also prolong their residence time, thereby increasing the propensity of thrombosis within MAs. Overall, our work suggests that computational simulations using particle-based models can help to understand the microvascular pathology pertaining to MAs in DR and provide insights to stimulate and steer new experimental and computational studies in this area.

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Effects of NO-Donors on Thrombus Formation and Microcirculation in Cerebral Vessels of the Rat

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650532 ◽

1996 ◽

Vol 76 (01) ◽

pp. 111-117 ◽

Cited By ~ 10

Author(s):

Yasuto Sasaki ◽

Junji Seki ◽

John C Giddings ◽

Junichiro Yamamoto

Keyword(s):

Blood Flow ◽

Thrombus Formation ◽

Dependent Manner ◽

Red Cell ◽

Cell Velocity ◽

Red Cell Velocity ◽

The Mean ◽

Wall Shear ◽

Dose Dependent

SummarySodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1), are known to liberate nitric oxide (NO). In this study the effects of SNP and SIN-1 on thrombus formation in rat cerebral arterioles and venules in vivo were assessed using a helium-neon (He-Ne) laser. SNP infused at doses from 10 Μg/kg/h significantly inhibited thrombus formation in a dose dependent manner. This inhibition of thrombus formation was suppressed by methylene blue. SIN-1 at a dose of 100 Μg/kg/h also demonstrated a significant antithrombotic effect. Moreover, treatment with SNP increased vessel diameter in a dose dependent manner and enhanced the mean red cell velocity measured with a fiber-optic laser-Doppler anemometer microscope (FLDAM). Blood flow, calculated from the mean red cell velocity and vessel diameters was increased significantly during infusion. In contrast, mean wall shear rates in the arterioles and venules were not changed by SNP infusion. The results indicated that SNP and SIN-1 possessed potent antithrombotic activities, whilst SNP increased cerebral blood flow without changing wall shear rate. The findings suggest that the NO released by SNP and SIN-1 may be beneficial for the treatment and protection of cerebral infarction

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A Locally Administered Novel Heparin Complex Attenuates Collagen-Induced Platelet Activation and Thrombosis In Vivo,

Blood ◽

10.1182/blood.v118.21.3361.3361 ◽

2011 ◽

Vol 118 (21) ◽

pp. 3361-3361

Author(s):

Riitta Lassila ◽

Annukka Jouppila ◽

Ulla M Marzec ◽

Stephen R Hanson

Keyword(s):

Blood Flow ◽

Platelet Aggregation ◽

Thrombus Formation ◽

Ptfe Graft ◽

Thrombin Time ◽

Thrombosis Model ◽

Baboon Model ◽

Induced Aggregation

Abstract Abstract 3361 We have developed a semi-synthetic antithrombotic heparin complex, APL001, to mimic mast cell-derived natural heparin proteoglycans (HepPG). HepPG attenuate platelet-collagen interactions under blood flow by inhibiting VWF- and GPIIb/IIIa -mediated platelet aggregation. In addition, rat-derived HepPG arrest platelet thrombus growth on collagen surfaces or at vascular injury sites, both in vitro and in vivo (Lassila et al.ATVB 1997, Kauhanen et al. ATVB 2000, Olsson et al. Thromb Haemost 2002). Our objective was to study the inhibitory capacity of APL001 for preventing human platelet aggregation in vitro and acute thrombosis in a baboon model in vivo. The effects of unfractionated heparin (UFH) and APL001 were compared in relevant coagulation assays (APTT, PT, thrombin time, anti-FXa activity, fibrinogen, FVIII:C and VWF activity (VWF:RCo) and antigen). Additionally, agonist-induced (collagen, ristocetin and ADP) platelet aggregation in citrate or hirudin-anticoagulated whole blood (Multiplate®) (n=10 healthy subjects), and platelet function analysis (PFA100®) in citrated platelet rich plasma (PRP) were assessed. In a well-established baboon thrombosis model a collagen-coated PTFE graft (length 2 cm, lumen 4 mm) was placed in an arterio-venous shunt. Prior to blood contact the thrombogenic surface was treated for 10 min with UFH or APL001 (both at 4 mg/mL). Thrombus formation was initiated by exposing the surface to blood flow (100 mL/min, shear rate 265−1), and the deposition of 111-In-labeled platelets and of fibrin was quantified continuously over 1h. Fibrin thrombus accumulation was assessed from the incorporation of circulating 125-I-fibrinogen. In the heparin-relevant coagulation tests APL001 was comparable or 20–30% more potent than UFH while FVIII, fibrinogen and VWF variables remained unaltered. In contrast to UFH, APL001 (300 μg/mL) consistently inhibited collagen- and ristocetin-induced platelet aggregation, whereas UFH had only a modest effect in comparison with PBS control (Table). ADP-induced aggregation was unaffected. Comparable results were observed in the PRP aggregation assay. PFA100 testing also demonstrated inhibitory effects. In the in vivo thrombosis model (n=4) APL001 reduced platelet deposition on collagen (vs. the results with UFH) by 34% (p=0.01), while platelet accumulation in distal propagated thrombus was reduced by 61% (p=0.16). APL001-treated surfaces accumulated 45% less fibrin than the UFH-treated surfaces (p=0.008). In conclusion, when compared with UFH APL001 inhibited both collagen- and ristocetin-induced platelet aggregation in human blood, while anticoagulant properties were comparable. In the absence of systemic antithrombotic drugs, exposure of APL001 to a highly thrombogenic collagen surface arrested thrombus formation in an in vivo baboon model. This finding suggests that locally administered APL001 alone, due to its dual antiplatelet and anticoagulant effects, may limit the growth and size of thrombus and thereby prevent subsequent thrombo-occlusion.TableAnticoagulantInhibition-% of platelet aggregation ± SDConc. 300 μg/mLnColl (3.2 μg/mL)Ristocetin (0.77 mg/mL)ADP (6.4 μM)CitrateAPL0011033 ± 1543 ± 166 ± 24UFH1011 ± 1323 ± 153 ± 7p value0.0030.0100.700HirudinAPL0011032 ± 1043 ± 178 ± 10UFH108 ± 1116 ± 166 ± 9p value0.0000.0020.600 Disclosures: Lassila: Aplagon: Chief Scientific Advisor.

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The P2Y12 Receptor Antagonist Selatogrel Dissolves Preformed Platelet Thrombi In Vivo

Journal of Clinical Medicine ◽

10.3390/jcm10225349 ◽

2021 ◽

Vol 10 (22) ◽

pp. 5349

Author(s):

Lydie Crescence ◽

Markus Kramberg ◽

Martine Baumann ◽

Markus Rey ◽

Sebastien Roux ◽

...

Keyword(s):

Blood Flow ◽

Guinea Pigs ◽

Thrombus Formation ◽

P2y12 Receptor ◽

Early Application ◽

Acute Thrombosis ◽

Thrombosis Model ◽

Platelet Thrombus ◽

Platelet Thrombi

Selatogrel, a potent and reversible antagonist of the P2Y12 receptor, inhibited FeCl3-induced thrombosis in rats. Here, we report the anti-thrombotic effect of selatogrel after subcutaneous applications in guinea pigs and mice. Selatogrel inhibited platelet function only 10 min after subcutaneous application in mice. In addition, in a modified Folts thrombosis model in guinea pigs, selatogrel prevented a decrease in blood-flow, indicative of the inhibition of ongoing thrombosis, approximately 10 min after subcutaneous injection. Selatogrel fully normalised blood flow; therefore, we speculate that it may not only prevent, but also dissolve, platelet thrombi. Thrombus dissolution was investigated using real-time intravital microscopy in mice. The infusion of selatogrel during ongoing platelet thrombus formation stopped growth and induced the dissolution of the preformed platelet thrombus. In addition, platelet-rich thrombi were given 30 min to consolidate in vivo. The infusion of selatogrel dissolved the preformed and consolidated platelet thrombi. Dissolution was limited to the disintegration of the occluding part of the platelet thrombi, leaving small mural platelet aggregates to seal the blood vessel. Therefore, our experiments uncovered a novel advantage of selatogrel: the dissolution of pre-formed thrombi without the disintegration of haemostatic seals, suggesting a bipartite benefit of the early application of selatogrel in patients with acute thrombosis.

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Shear rate gradients promote a bi-phasic thrombus formation on weak adhesive proteins, such as fibrinogen in a VWF-dependent manner

Haematologica ◽

10.3324/haematol.2019.235754 ◽

2019 ◽

Vol 105 (10) ◽

pp. 2471-2483 ◽

Cited By ~ 2

Author(s):

Nicolas Receveur ◽

Dmitry Nechipurenko ◽

Yannick Knapp ◽

Aleksandra Yakusheva ◽

Eric Maurer ◽

...

Keyword(s):

Blood Flow ◽

Shear Rate ◽

Steady Flow ◽

Thrombus Formation ◽

Fiber Formation ◽

Second Phase ◽

Dependent Manner ◽

Flow Acceleration ◽

Adhesive Proteins

Blood flow profoundly varies throughout the vascular tree due to its pulsatile nature and to the complex vessel geometry. While thrombus formation has been extensively studied in vitro under steady flow, and in vivo under normal blood flow conditions, the impact of complex hemodynamics such as flow acceleration found in stenosed arteries has gained increased appreciation. We investigated the effect of flow acceleration, characterized by shear rate gradients, on the function of platelets adhering to fibrinogen, a plasma protein which plays a key role in hemostais and thrombosis. While we confirmed that under steady flow, fibrinogen only supports single platelet adhesion, we observed that under shear rate gradients, this surface becomes highly thrombogenic, supporting efficient platelet aggregation leading to occlusive thrombus formation. This shear rate gradient-driven thrombosis is biphasic with an initial step of slow platelet recruitment supported by direct plasma VWF adsorption to immobilized fibrinogen and followed by a second phase of explosive thrombosis initiated by VWF fiber formation on platelet monolayers. In vivo experiments confirmed that shear rate gradients accelerate thrombosis in a VWF-dependent manner. Together, this study characterizes a process of plasma VWF-dependent accelerated thrombosis on immobilized fibrinogen in the presence of shear rate gradients.

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DIPYRIDAMOLE ALONE OR WITH LOW DOSE ASPIRIN DOES NOT PREVENT ACUTE PLATELET THROMBUS FORMATION IN STENOSED DOG CORONARY ARTERIES

10.1055/s-0038-1643577 ◽

1987 ◽

Author(s):

J D Folts ◽

S R Smith

Keyword(s):

Clinical Trials ◽

Blood Flow ◽

Coronary Arteries ◽

Low Dose ◽

Thrombus Formation ◽

Arterial Stenosis ◽

In Vivo Model ◽

Acute Ischemia ◽

Pig Coronary Arteries

Dipyridamole (Dip) is reputed to inhibit (I) platelet aggregation (PA) and acute thrombus formation (ATF) by two mechanisms including inhibiting 1.) platelet (Pt) phosphodiesterase, 2.) adenosine (A) reuptake by red cells, which should raise plasma A. Both effects should raise Pt cyclic AMP and thus be a potent platelet inhibitor (PI). Because aspirin (AS) inhibits Pt thromboxane A2 production, a synergistic (S) PI effect for ASA and Dip given together has been postulated and used in clinical trials but this S has never been shown to I ATP in any in vivo model, which reasonably mimics human arterial stenosis. We have shown that ATF followed by embolization, occurs periodically in mechanically stenosed (MS) monkey and rabbit carotid arteries, and dog (D) and pig coronary arteries (CA), causing cyclical reductions in coronary blood flow (CRF) (measured with EMF probes) and periodic acute ischemia, and that these CRF can be abolished with a variety of PI including 3.0 mg/kg of ASA. To determine if there is a S effect between ASA and Dip, in open chest D, Dip was given, 2.0 mg/kg IV to D with a MS circumflex CA and having 14±5 CRF’s per hour, due to periodic ATF; and simultaneously flow measured in an unstenosed normal LAD CA. The frequency and size of CRF’s were not changed by Dip, although ABP decreased 21±9 mm Hg and blood flow in the unstenosed LAD increased 259±47%. A low dose of ASA, 1.0 mg/kg, which by itself diminishes but does not abolish CRF’s in this model was given IV 10 min. after Dip and CRF’s continued unchanged. When a second dose of ASA 1.0 mg/kg was given IV to reach the minimum effective dose of ASA in this model, CRF were abolished in all D. Thus Dip was not effective alone or in combination with low dose ASA to I CRF in this model which simulates the patient with stenosed CA. The majority of clinical trials that show inhibition of ATF, used ASA and Dip together without 3 separate patient groups on Dip alone, ASA alone and ASA plus Dip. The widespread use of Dip with ASA to prevent ATF in man needs to be reevaluated.

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Reduced thrombus stability in mice lacking the α2A-adrenergic receptor

Blood ◽

10.1182/blood-2005-12-4835 ◽

2006 ◽

Vol 108 (2) ◽

pp. 510-514 ◽

Cited By ~ 42

Author(s):

Miroslava Požgajová ◽

Ulrich J. H. Sachs ◽

Lutz Hein ◽

Bernhard Nieswandt

Keyword(s):

Blood Flow ◽

Adrenergic Receptor ◽

Thrombus Formation ◽

Fold Increase ◽

Wild Type ◽

Perfusion Studies ◽

G Protein Coupled ◽

Deficient Mice

Platelet activation plays a central role in hemostasis and thrombosis. Many platelet agonists function through G-protein–coupled receptors. Epinephrine activates the α2A-adrenergic receptor (α2A) that couples to Gz in platelets. Although α2A was originally cloned from platelets, its role in thrombosis and hemostasis is still unclear. Through analysis of α2A-deficient mice, variable tail bleeding times were observed. In vitro, epinephrine potentiated activation/aggregation responses of wild-type but not α2A-deficient platelets as determined by flow cytometry and aggregometry, whereas perfusion studies showed no differences in platelet adhesion and thrombus formation on collagen. To test the in vivo relevance of α2A deficiency, mice were subjected to 3 different thrombosis models. As expected, α2A-deficient mice were largely protected from lethal pulmonary thromboembolism induced by the infusion of collagen/epinephrine. In a model of FeCl3-induced injury in mesenteric arterioles, α2A–/– mice displayed a 2-fold increase in embolus formation, suggesting thrombus instability. In a third model, the aorta was mechanically injured, and blood flow was measured with an ultrasonic flow probe. In wild-type mice, all vessels occluded irreversibly, whereas in 24% of α2A-deficient mice, the initially formed thrombi embolized and blood flow was reestablished. These results demonstrate that α2A plays a significant role in thrombus stabilization.

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Microelectrode Sensor for Real-Time Measurements of Nitrite in the Living Brain, in the Presence of Ascorbate

Biosensors ◽

10.3390/bios11080277 ◽

2021 ◽

Vol 11 (8) ◽

pp. 277

Author(s):

Tiago Monteiro ◽

Cândida Dias ◽

Cátia F. Lourenço ◽

Ana Ledo ◽

Rui M. Barbosa ◽

...

Keyword(s):

Blood Flow ◽

Real Time ◽

Brain Research ◽

Electrochemical Techniques ◽

Spatial Dynamics ◽

Fast Scan Cyclic Voltammetry ◽

Hypoxic Conditions ◽

The Brain

The impaired blood flow to the brain causes a decrease in the supply of oxygen that can result in cerebral ischemia; if the blood flow is not restored quickly, neuronal injury or death will occur. Under hypoxic conditions, the production of nitric oxide (●NO), via the classical L-arginine–●NO synthase pathway, is reduced, which can compromise ●NO-dependent vasodilation. However, the alternative nitrite (NO2−) reduction to ●NO, under neuronal hypoxia and ischemia conditions, has been viewed as an in vivo storage pool of ●NO, complementing its enzymatic synthesis. Brain research is thus demanding suitable tools to probe nitrite’s temporal and spatial dynamics in vivo. In this work, we propose a new method for the real-time measurement of nitrite concentration in the brain extracellular space, using fast-scan cyclic voltammetry (FSCV) and carbon microfiber electrodes as sensing probes. In this way, nitrite was detected anodically and in vitro, in the 5–500 µM range, in the presence of increasing physiological concentrations of ascorbate (100–500 µM). These sensors were then tested for real-time and in vivo recordings in the anesthetized rat hippocampus; using fast electrochemical techniques, local and reproducible transients of nitrite oxidation signals were observed, upon pressure ejection of an exogenous nitrite solution into the brain tissue. Nitrite microsensors are thus a valuable tool for investigating the role of this inorganic anion in brain redox signaling.

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Functional imaging of shear-dependent activity of ADAMTS13 in regulating mural thrombus growth under whole blood flow conditions

Blood ◽

10.1182/blood-2007-09-110700 ◽

2008 ◽

Vol 111 (3) ◽

pp. 1295-1298 ◽

Cited By ~ 48

Author(s):

Yasuaki Shida ◽

Kenji Nishio ◽

Mitsuhiko Sugimoto ◽

Tomohiro Mizuno ◽

Masaaki Hamada ◽

...

Keyword(s):

Blood Flow ◽

Shear Rate ◽

Whole Blood ◽

Thrombus Formation ◽

Arterial Occlusion ◽

Generation Process ◽

Flow Conditions ◽

Normal Hemostasis

Abstract The metalloprotease ADAMTS13 is assumed to regulate the functional levels of von Willebrand factor (VWF) appropriate for normal hemostasis in vivo by reducing VWF multimer size, which directly represents the thrombogenic activity of this factor. Using an in vitro perfusion chamber system, we studied the mechanisms of ADAMTS13 action during platelet thrombus formation on a collagen surface under whole blood flow conditions. Inhibition studies with a function-blocking anti-ADAMTS13 antibody, combined with immunostaining of thrombi with an anti-VWF monoclonal antibody that specifically reflects the VWF-cleaving activity of ADAMTS13, provided visual evidence for a shear rate–dependent action of ADAMTS13 that limits thrombus growth directly at the site of the ongoing thrombus generation process. Our results identify an exquisitely specific regulatory mechanism that prevents arterial occlusion under high shear rate conditions during mural thrombogenesis.

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ANTI-THROMBOTIC EFFECTS OF E-5510 IN EXPERIMENTAL THROMBOSIS MODELS

10.1055/s-0038-1643429 ◽

1987 ◽

Author(s):

T Fujimori ◽

T Saeki ◽

K Harada ◽

M Sato ◽

N Ohshima

Keyword(s):

Blood Flow ◽

Oral Administration ◽

Guinea Pigs ◽

Vessel Wall ◽

Pulmonary Thromboembolism ◽

Ex Vivo ◽

Thrombus Formation ◽

Platelet Thrombus

A new agent developed in our laboratory, 4-cyano-5,5-bis(4-methoxyphenyl)-4-pentenoic acid (E-5510), suppressed various human platelet functions in vitro. The compound also showed quite potent ex vivo anti-platelet effects in many experimentalanimals. It is well known that anti-platelet effects are not always parallel to anti-thrombotic effects. Thus, in order to predict the efficacy of E-5510 in thrombotic disorders, the anti-thrombotic effects were examined in 3 different animal models of thrombosis.(1) Anti-thrombotic effect in an extracorporeal shunt model Two hrs after oral administration of the drug to guinea pigs,an extracorporeal shunt between the right carotid artery and the left jugular vein was performed. The thrombus formation on a silk thread inserted in the shunt tube was quantitated by measuring the time from the onset of circulation to the stenosis of blood flow. E-5510 dose-dependently inhibited thrombus formation, the minimum effective dose being 0.03 mg/kg.(2) Effect on microthrombus formation in mesenteric arteriole In order to evaluate the effect on intravascular platelet thrombus formation, thrombosis was induced in vivo in mesenteric arteriole in guinea pigs with filtered light from a mercury lamp and an intravenous fluorescent dye in an intravital microscope system (M. Sato and N. Ohshima, Thromb. Res.,35, 319, 1984). The thrombus formation was quantitated by measuring the time taken for circulating platelets to begin to adhere to vessel wall and the time taken for blood flow to stop completely due to fully developed thrombus. Both the time required for platelet adhesion to vessel wall and for platelet thrombus formation were significantly prolonged after oral administration of E-5510.(3) Effect on pulmonary thromboembolism Acute pulmonary thromboembolism was induced in mice by a bolus intravenous injection of arachidonic acid, and mortality was determined 3 min later. E-5510 dose-dependently reduced pulmonary thromboembolic mortality, and its ED50 was 0.11 mg/kg. The results described above indicate thatE-5510 may have beneficial effects in clinical treatments of thrombotic disease.

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Adamts-18 Is a Novel Candidate Gene Of Vascular Development That Is Related To Aggravated Thrombosis: Evidence From a Adamts-18 Knock Out Mice

Blood ◽

10.1182/blood.v122.21.31.31 ◽

2013 ◽

Vol 122 (21) ◽

pp. 31-31

Author(s):

Wei Zhang ◽

Dawei Bu ◽

Suying Dang ◽

Tao Hong ◽

Thomas Wisniewski

Keyword(s):

Blood Flow ◽

Carotid Artery ◽

Middle Cerebral Artery ◽

Cerebral Artery ◽

Common Carotid Artery ◽

Conflicts Of Interest ◽

Thrombus Formation ◽

Surface Display

Abstract HIV-ITP patients have a unique antibody (Ab) against platelet GPIIIa49-66 which induces oxidative platelet fragmentation in the absence of complement (Cell 106: 551, 2001; JCI 113: 973, 2004). The search for a physiologic ligand that could induce this reaction was undertaken by panning the GPIIIa49-66 peptide with a phage surface display 7-mer peptide library. From 20 positive clones, 1 had 70% identity with a C-terminal region of ADAMTS-18 (a disintegrin and metalloproteinase with thrombospondin (TSR)-like motif 18), which is secreted by endothelial cell (EC). The recombinant C-terminal fragment of ADAMTS-18 can completely dissolve platelet aggregates formed in vitro. Moreover, this fragment lyses thrombi formed in the cerebral artery of mice and reduces infarction and neurologic impairment in murine ischemic stroke model (Blood 113: 6051, 2009). However, whether ADAMTS-18 represents the dominant physiologic mechanism controlling thrombus dissolution in vivo remains to be clarified. Here, we used ADAMTS-18-deficient (ADAMTS-18-/-) mice to study the contributions of ADAMTS-18 to thrombus formation in vivo. To investigate possible functional differences between WT and ADAMTS-18-/- platelets, we tested WT and ADAMTS-18-/- platelets in a model of pulmonary thromboembolism induced by infusion of a mixture of platelet agonist collagen (25 µg per mouse) and epinephrine (1 µg per mouse). In lung tissue Hematoxylin and eosin-stained (HE) slides, the mean number of thrombi per lung was same in the ADAMTS-18-/- group compared with WT group (163.7 ±14.38 vs 174.9 ±11.73, n=30/group, P=0.5480). In vitro, there is no difference between WT and ADAMTS-18-/- platelet aggregation trace and activation initiated by various platelet agonists ADP (10 µM) or collagen (2 µg/mL). No difference was noted on WT and ADAMTS-18-/- platelet adhesion on immobilized ligand (fibrinogen). These results indicated ADAMTS-18 had no effect on platelet function. We next evaluate the effect of ADAMTS-18 on thrombus formation in a second well-established carotid artery thrombosis model, which is induced by 10% FeCl3 patch. In the process of surgical operation, we unexpectedly observed that all ADAMTS-18-/- mice have premature common carotid artery bifurcation compared with WT mice. A Doppler flow monitor showed ADAMTS-18-/- mice exhibited significantly reduced carotid artery blood flow than WT mice (ADAMTS-18-/- vs WT, 0.5 ± 0.11 vs 0.75 ± 0.21 mL/min, n=7/group, P=0.0298), which results in shortened time of thrombus formation (ADAMTS-18-/- vs WT, 452.17 ± 68.88 vs 611.43 ± 92.02 sec, n=7/group, P=0.0005 ). Immunohistochemistry staining showed that the common carotid artery of ADAMTS-18-/- mice had increased adventitial collagen deposition compared with WT mice. In vivo matrigel plug assay demonstrated that ADAMTS-18-/- mice had significantly lower density of blood vessels compared to the WT mice. Since the middle cerebral artery arises from the internal carotid artery, we conjecture that ADAMTS-18-/- mice would have aggravated brain infarction for the less cerebral blood flow supplying. This proved to be true. In transient middle cerebral artery occlusion (tMCAO) model, the infarction size in ADAMTS-18-/- mice was significantly larger than in WT mice (mean infarction %, 25.68 ± 4.13 vs 17.41 ± 3.24, n=8, P=0.0012). Taken together, these observations suggest vasculature is the potential site of action of ADAMTS-18. To our knowledge, this is the first validation study of linkage and association of ADAMTS-18 as a pro-vasculature gene that is related to aggravated thrombosis. Disclosures: No relevant conflicts of interest to declare.

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