Author + information
- Received February 16, 2018
- Revision received June 7, 2018
- Accepted June 10, 2018
- Published online August 20, 2018.
- Federico Moccetti, MDa,
- Eran Brown, MSa,
- Aris Xie, MSa,
- William Packwood, BSa,
- Yue Qi, MDa,
- Zaverio Ruggeri, PhDb,
- Weihui Shentu, MDa,
- Junmei Chen, PhDc,
- Jose A. López, MDc and
- Jonathan R. Lindner, MDa,d,∗ (, )@OHSUSOM
- aKnight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon
- bDepartment of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California
- cBloodworks NW, Seattle, Washington
- dOregon National Primate Research Center, Oregon Health & Science University, Portland, Oregon
- ↵∗Address for correspondence:
Dr. Jonathan R. Lindner, Knight Cardiovascular Institute, UHN-62, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239.
Background In the months after acute myocardial infarction (MI), risk for acute atherothrombotic events in nonculprit arteries increases several fold.
Objectives This study investigated whether sustained proinflammatory and prothrombotic endothelial alterations occur in remote vessels after MI.
Methods Wild-type mice, atherosclerotic mice with double knockout (DKO) of the low-density lipoprotein receptor and Apobec-1, and DKO mice treated with the Nox-inhibitor apocynin were studied at baseline and at 3 and 21 days after closed-chest MI. Ultrasound molecular imaging of P-selectin, vascular cell adhesion molecule (VCAM)-1, von Willebrand factor (VWF) A1-domain, and platelet GPIbα was performed. Intravital microscopy was used to characterize post-MI leukocyte and platelet recruitment in the remote microcirculation after MI.
Results Aortic molecular imaging for P-selectin, VCAM-1, VWF-A1, and platelets was increased several-fold (p < 0.01) 3 days post-MI for both wild-type and DKO mice. At 21 days, these changes resolved in wild-type mice but persisted in DKO mice. Signal for platelet adhesion was abolished 1 h after administration of ADAMTS13, which regulates VWF multimerization. In DKO and wild-type mice, apocynin significantly attenuated the post-MI increase for molecular targets, and platelet depletion significantly reduced P-selectin and VCAM-1 signal. On intravital microscopy, MI resulted in remote vessel leukocyte adhesion and platelet string or net complexes. On histology, high-risk inflammatory features in aortic plaque increased in DKO mice 21 days post-MI, which were completely prevented by apocynin.
Conclusions Acute MI stimulates a spectrum of changes in remote vessels, including up-regulation of endothelial inflammatory adhesion molecules and platelet-endothelial adhesion from endothelial-associated VWF multimers. These remote arterial alterations persist longer in the presence of hyperlipidemia, are associated with accelerated plaque growth and inflammation, and are attenuated by Nox inhibition.
Major acute atherothrombotic events such as myocardial infarction (MI), stroke, or limb ischemia lead to a markedly increased risk for recurrent events in separate vascular territories. After MI, the risk for stroke or recurrent MI from nonculprit lesions is increased by several-fold over the ensuing 6 to 12 months (1–3). These findings indicate that a focal ischemic event can lead to systemic adverse vascular responses. Murine studies have demonstrated that acute MI triggers the splenic production and mobilization of inflammatory Ly-6Chigh monocytes, and the accelerated entry of these cells and other CD11b+ myeloid cells into remote arterial plaque for weeks after the initial event (4). With regard to remote vascular endothelial responses, MI in mice leads to up-regulation of mRNA for endothelial cell adhesion molecules within the noninfarct myocardial microcirculation (5). However, little is known about endothelial-specific alterations in remote arterial atherosclerotic lesions, including in noncoronary locations.
In this study, in vivo imaging methods, unique in their ability to investigate events at the endothelial-blood pool interface, were used to study post-MI endothelial alterations in remote arteries that can predispose to accelerated plaque growth and atherothrombotic events. Contrast-enhanced ultrasound (CEU) molecular imaging and direct microvascular observation with intravital microscopy were used to characterize the endothelial responses that occur in remote arteries after MI. CEU molecular imaging with targeted microbubble contrast agents that are confined to the vascular compartment was selected based on extensive experience in murine and nonhuman primate models to detect arterial events that occur at the endothelial-blood pool interface (6–8). Specifically, we hypothesized that acute MI leads to: 1) remote arterial up-regulation of endothelial cell adhesion molecules on the plaque surface; and 2) platelet adhesion to the intact endothelial surface, which contributes to proinflammatory activation and can occur, in part, from abnormal, endothelial-associated, ultra-large, self-associated multimers of von Willebrand factor (VWF) that occur secondary to dysregulation of normal proteolytic regulation by ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type I repeats-13) (9–11).
The study was approved by the Animal Care and Use Committee of the Oregon Health & Science University. We studied wild-type C57Bl/6 mice and mice with susceptibility to age-related atherosclerosis through dual gene-targeted deletion or “double knockout” (DKO) of the low-density lipoprotein receptor and apolipoprotein-B mRNA editing enzyme catalytic polypeptide 1 (Apobec-1) on a C57Bl/6 background. DKO mice develop reproducible, age-dependent development of atherosclerosis on a chow diet (6,12), and were studied at 20 to 25 weeks of age, when plaque size is modest with early intraluminal encroachment (6). For all studies, mice were anesthetized with 1.0% to 2.0% inhaled isoflurane, and a jugular cannula was placed for intravenous (IV) injection of contrast agents or drugs.
Imaging study design
The proximal thoracic aorta was selected as a remote arterial site to study endothelial activation after MI. CEU molecular imaging of the aorta was performed using microbubble contrast agents targeted to P-selectin (MBP), vascular cell adhesion molecule (VCAM)-1 (MBV), GPIbα as an indicator of platelet adhesion (MBPlt), and endothelial VWF (MBVWF). Studies were also performed with control nontargeted microbubbles (MB). Animals were studied in the following experimental conditions:
1. Molecular imaging was performed at baseline and at either 3 or 21 days after MI in wild-type and DKO mice. Mice were also studied 3 days after sham procedure.
2. Molecular imaging was performed 3 days after MI in DKO mice treated 1 h prior to imaging with recombinant human ADAMTS13 (5 μg IV), the key regulatory protease that reduces VWF multimer size through cleavage at the VWF A2 domain (10,11).
3. Molecular imaging was performed 3 and 21 days after MI in DKO mice treated with apocynin (50 mg/kg/day) starting on the day of MI. Apocynin (acetovanillone) is a potent inhibitor of NADPH-oxidase (Nox), which has been implicated in transcriptional up-regulation of adhesion molecule expression and has been demonstrated to reduce platelet-endothelial adhesion in early and late atherosclerosis (13,14).
4. Molecular imaging was performed 21 days after MI in DKO mice undergoing platelet depletion by IV injection of 2 μg/g rat antimouse GPIbα monoclonal antibody (7) at days 1, 4, 9, and 15 post-MI to determine the contribution of platelets to sustained endothelial adhesion molecule expression.
A closed-chest model of MI was used to allow for the resolution of the acute inflammatory responses after thoracotomy and cardiac exposure. At least 5 days prior to scheduled MI, mice were anesthetized, intubated, and placed on positive pressure mechanical ventilation with weight-adjusted tidal volumes and respiratory rates. A limited left lateral thoracotomy was performed to expose only the basal anterior wall. A 6-0 prolene suture was placed under the left anterior descending coronary artery but was left unsecured. The free ends of the suture were exteriorized through the chest wall and left in a subcutaneous location after closure. After 5 to 7 days, mice were anesthetized, the suture was exteriorized through a limited skin incision, and the tension was placed on the suture for 40 min to produce ST-segment elevation on electrocardiographic monitoring and wall motion abnormalities on high-frequency transthoracic 2-dimensional echocardiography (Vevo 2100, Visualsonics Inc., Toronto, Ontario, Canada). Sham-treated animals received a suture without tightening.
Targeted microbubble preparation
Biotinylated lipid-shelled decafluorobutane microbubbles were prepared by sonication of a gas-saturated aqueous suspension of distearoylphosphatidylcholine (2 mg/ml), polyoxyethylene-40-stearate (1 mg/ml), and distearoylphosphatidylethanolamine-PEG(2000)biotin (0.4 mg/ml). Conjugation of biotinylated ligand to the microbubble surface was performed with biotin-streptavidin bridging as previously described (15). Ligands used for targeting were: dimeric murine recombinant A1 domain of VWF A1 (mature VWF amino acids 445 to 716) for targeting platelet GPIbα for MBPlt, a cell-derived peptide representing the N-terminal 300 amino acids of GPIbα for MBVWF (7), and monoclonal antibodies against the extracellular domain of either P-selectin (RB40.34, BD Biosciences, San Jose, California), or VCAM-1 (clone 429, BD Biosciences) for MBP and MBV, respectively. Control MB were prepared with isotype control antibody (R3-34, BD Biosciences). Microbubble concentrations and size distributions were measured by electrozone sensing (Multisizer III, Beckman Coulter, Brea, California).
CEU molecular imaging of the ascending aorta and proximal aortic arch was performed using a right parasternal window with a linear-array probe (Sequoia, Siemens Medical Systems, Mountain View, California). Multipulse phase-inversion and amplitude-modulation imaging at 7 MHz was performed with a dynamic range of 55 dB and a mechanical index of 1.0. Gain was set at a level that just eliminated pre-contrast background speckle and kept constant for all studies. Images were acquired 8 min after intravenous injection of targeted or control microbubbles (1 × 106), performed in random order, to allow almost all free microbubbles to clear from blood pool. Signal from retained microbubbles alone was determined, as previously described, by acquiring the first ultrasound frame and then digitally subtracting several averaged frames obtained after complete destruction of microbubbles at a mechanical index of 1.4 to eliminate signal from the low concentration of freely-circulating microbubbles in the blood pool (15). Signal intensity was measured from a region-of-interest encompassing the entire ascending aorta to just beyond the origin of the brachiocephalic artery. Region selection was facilitated by fundamental 2-dimensional imaging at 14 MHz acquired after each CEU imaging sequence.
High-frequency (40 MHz) transthoracic echocardiography was performed at each post-MI study interval in DKO mice to evaluate any differences in left ventricular (LV) diameter, infarct size, stroke volume, or peak aortic shear rate related to treatment with apocynin. Parasternal long- and short-axis imaging planes at the midventricular level were used to assess infarct size quantified by calculating a wall motion score index. LV dimensions at end-systole and -diastole were measured from the parasternal long-axis view using linear measurements of the LV at the level of the mitral leaflet tips during diastole. Stroke volume was calculated as the product of the LV outflow tract cross-sectional area and time-velocity integral on pulsed-wave Doppler. Longitudinal strain was calculated using speckle-tracking echocardiography from a parasternal long-axis view and was quantified as the average of a standard single 6-segment model.
Histology of the aortic root and the mid-ascending aorta for DKO mice was performed 21 days or 3 months after MI (randomized evenly for each group). Perfusion-fixed transaxial sections were stained with Masson’s trichrome for assessment of plaque area and collagen content. Immunohistochemistry was performed with antibody against Mac-2 (M3/38, Thermofisher Science, Waltham, Massachusetts) to assess macrophage content, against CD41 (sc20234, Santa Cruz Biotechnology, Santa Cruz California) for platelets, and for VCAM-1 (BS-0369r, Bioss Inc., Atlanta, Georgia). For each epitope, secondary staining was performed with species-appropriate secondary antibodies labeled with ALEXAFluor-488, -555, or -594 (Invitrogen, Grand Island, New York). Plaque collagen content, necrotic core, and MAC-2 area are expressed as percent of plaque area.
Direct observation of post-MI potentiation of platelet- and leukocyte-endothelial interactions was performed with intravital microscopy in wild-type and DKO mice, with or without MI, 3 days prior to study. Mice were anesthetized with ketamine and xylazine (intraperitoneally), and the cremaster muscle was exteriorized and prepared for intravital microscopy as previously described (16). Microscopy was performed with combined fluorescent epi-illumination and low-intensity transillumination (Axioskop2-FS, Carl Zeiss, Inc., Thornwood, New York) and digital recordings were made with a high-resolution CCD camera (C2400, Hamamatsu Photonics, Hamamatsu City, Japan). In vivo fluorescent labeling of platelets was performed with rhodamine-6G (1 mg/ml, 75 μl IV). The number of adherent leukocytes and platelet adhesive events (>5 s), and the formation of platelet “strings” indicative of ultralarge VWF multimers were quantified as fluorescent platelet area normalized to vessel area. Rolling velocity of leukocytes in 15- to 35-μm post-capillary venules was calculated by the distance traveled by video calipers divided by time.
Data analysis was performed with Prism version 7.0a (Graph Pad, La Jolla, California). Continuous variables that were normally distributed are displayed as mean ± SD unless stated otherwise, whereas those that were not normally distributed are displayed as box-whisker plots with a bar representing median, box representing 25% to 75% quartiles, and whiskers representing range. Student’s t-tests (paired or unpaired) were performed for comparisons of normally distributed data. For non-normally distributed data, either a Mann-Whitney U test or Wilcoxon signed rank test was used as appropriate according to experimental conditions (group-wise comparisons versus paired data within a group). For multiple comparisons, a 1-way analysis of variance was performed for normally distributed data with post-hoc testing with Holm-Sidak’s multiple comparisons correction. A Kruskal-Wallis test followed by Dunn’s multiple comparison test was performed for non-normally distributed data.
Post-MI ventricular function and aortic shear
Electrocardiographic ST-segment elevation and regional hypokinesis or akinesis involving the mid to distal anterior, anterolateral, and anteroseptal walls on echocardiography was observed in all mice at the time of closed-chest left anterior descending coronary artery ischemia, but were not seen in any of the animals undergoing sham surgical procedure. MI resulted in LV enlargement, reduction of LV systolic function and stroke volume at days 3 and 21 (Figure 1). Chronic therapy with apocynin starting on the day of MI did not affect the infarct-related changes in LV dimension or function on echocardiography.
Remote arterial endothelial activation and platelet adhesion after MI
At baseline prior to any procedures, molecular imaging signal enhancement of the thoracic aorta for endothelial P-selectin, VCAM-1, VWF A1-domain, and platelet GPIbα were all found to be higher in DKO than wild-type mice (Figure 2A), consistent with greater aortic endothelial adhesion molecule expression, endothelial-associated active form of VWF, and platelet adhesion in DKO mice. In DKO but not wild-type mice, signal for all 4 targeted microbubble agents was significantly greater than for control microbubbles. At day 3 post-MI, signal for endothelial P-selectin, VCAM-1, VWF, and platelet GPIbα all increased significantly in both wild-type and DKO mice (Figures 2B to 2D). In wild-type mice, the post-MI increase for all 4 targeted agents completely resolved and returned to baseline levels at day 21, whereas in DKO mice, signal enhancement remained elevated at 21 days. Signal from control MBs was low in all mice and did not change significantly after MI. Sham procedure did not produce any changes on CEU molecular imaging (Figure 2E).
Effect of ADAMTS13 on platelet adhesion
In DKO mice, aortic CEU molecular imaging 3 days post-MI was performed before and 1 h after treatment with recombinant ADAMTS13, a protease that removes endothelial-associated VWF and regulates VWF multimer size (10,17). ADAMTS13 abolished platelet GPIbα signal (Figure 3A), indicating that platelet adhesion in remote vessels after MI occurs secondary to inducible abnormalities in the enzymatic regulation of endothelial-associated VWF. The lack of effect on P-selectin signal confirmed that this signal was primarily endothelial rather than platelet in origin.
Effect of platelet depletion on endothelial activation
In DKO mice studied at day 21, platelet immune-depletion started on day 1 after MI completely prevented the post-MI increase in platelet adhesion on aortic molecular imaging, and also significantly but modestly reduced endothelial P-selectin and VCAM-1 signal enhancement (Figure 3B).
Nox inhibition reduces endothelial activation and platelet adhesion
Apocynin started on the day of MI significantly attenuated the post-MI increase in remote aortic molecular imaging signal for P-selectin, VCAM-1, platelet GPIbα, and VWF A-1 in wild-type mice at day 3 and in DKO mice at days 3 and 21 (Figures 4A to 4C).
Remote endothelial activation in the microcirculation
Intravital microscopy of the cremaster muscle was used to interrogate for similar post-MI remote endothelial-related events in the microcirculation. Venular leukocyte rolling velocity in both wild-type and DKO mice decreased after MI (Figures 5A to 5D, Online Videos 1, 2, 3 and 4). Leukocyte firm adhesion in venules and platelet adhesion were also significantly increased 3 days post-MI in both wild-type and DKO mice (Figures 5E to 5G). Almost all platelet adhesion events in nonischemic mice were in the form of single platelets or small linear aggregates, whereas platelet adhesion post-MI was in the form of large string or net assemblies, consistent with ultralarge multimers of VWF on the endothelium or anchored to adherent leukocyte-platelet hetero-aggregates (Figures 5H to 5K, Online Videos 1, 2, 3 and 4).
Post-MI acceleration of plaque progression is suppressed with Nox-2 inhibition
Aortic histology demonstrated that at 21 days, DKO mice undergoing MI compared with sham-treated mice had larger plaque area, larger necrotic core area, increased macrophage content, greater VCAM-1 staining, and lower collagen content (Figure 6, Online Figure 1). The increase in VCAM-1 staining was present in endothelium overlying atherosclerotic plaques, as well as nonplaque endothelium. Apocynin therapy in post-MI DKO mice attenuated all of the high-risk features in terms of macrophage content, VCAM-1 staining, and collagen content, whereas the reduction in plaque size did not reach statistical significance. Histology obtained at 3 months demonstrated persistently larger plaque size and macrophage content and lower collagen content in DKO mice undergoing MI compared with sham-treated control mice (Online Figure 2).
Our results indicate that acute MI stimulates a spectrum of adverse events in remote arterial and microvascular beds including endothelial up-regulation of VCAM-1 and P-selectin, and platelet adhesion that occurs through primarily through VWF that is either endothelial-associated or from adherent leukocyte-platelet complexes (Central Illustration). These adverse changes at the vascular endothelial surface persist longer when there is pre-existing atherosclerosis and hyperlipidemia, and are associated with acceleration of plaque growth and inflammation in arteries spatially remote from the MI. Our data also suggest that reduction of oxidative stress through Nox inhibition attenuates adverse endothelial responses in remote arteries.
There is increasing evidence that global inflammatory responses after a major acute ischemic event contribute to the heightened risk for events in remote arterial beds. Leukocytosis and elevated plasma levels of cytokines and chemokines commonly occurs in the subacute phase after MI, the degree of which is associated with intermediate-term prognosis (18–20). In studies performed in atherosclerotic mice, acute MI has been shown to lead to an increase of proinflammatory Ly-6Chigh monocytes and other myeloid cells (4). Carotid activity with 18F-fluorodeoxyglucose positron emission tomography has been shown to be higher in patients with recent acute MI than those with chronic stable angina (21), although cross-sectional design precluded any comments on causation. Little is known regarding endothelial changes that promote the recruitment of innate immune cells into atherosclerotic lesions in distant vessels after MI.
We applied CEU molecular imaging with targeted tracers confined to the vascular compartment to reveal that reperfused MI triggers remote arterial up-regulation of endothelial cell adhesion molecules that are critical for the recruitment of inflammatory cells (9,22). Although our primary aim was to study events in large arteries, corroborative evidence in other vascular territories was provided by intravital microscopy of a noncoronary microvascular bed, where leukocyte rolling velocity and adhesion were used as indicators of endothelial expression of selectins and integrin counter-receptors. These studies confirmed that MI promotes global endothelial activation. We believe that endothelial activation was in part responsible for the acceleration of plaque growth, inflammation, and necrotic core at 21 days and 3 months post-MI; these effects are consistent with a more “high risk” plaque appearance on histology. However, it is possible that increased plaque macrophage content contributed to the persistence of the endothelial activation at day 21 in DKO mice, consistent with the feed-forward nature of plaque inflammation.
Our investigation of endothelial-platelet adhesion after MI is based on the mounting evidence that these interactions play a multifactorial role in promoting plaque inflammation (9,23). Local release of platelet-derived proinflammatory cytokines and CD40L leads to monocyte activation, up-regulation of endothelial adhesion molecules, formation of neutrophil extracellular traps, and the generation of reactive oxygen species (ROS) (9,23–25). Inhibition of platelet activation or adhesion has been shown in animal models to reduce plaque size and inflammation (26,27).
Platelet adhesion in early- to moderate-stage atherosclerosis is primarily mediated by interactions between the GPIbα component of the GPIb/IX/V complex on platelets and the A1 domain of “activated” VWF (27–29). This interaction appears to be facilitated by association of VWF with the intact endothelial surface and ineffective cleavage at the A2 domain by ADAMTS13, resulting in ultra-large multimers of self-associated VWF (17,29,30). In this study, molecular imaging of a remote artery revealed a large increase in endothelial VWF-A1 domain and platelet adhesion after MI, which paralleled endothelial inflammatory responses. Platelet signal in post-MI DKO mice was entirely eliminated by exogenous ADAMTS13 implicating abnormal regulation of VWF. Again, intravital microscopy provided corroborative evidence, such as the formation of large linear platelet clusters that were dynamic in size and oscillated in flow, characteristic of the large VWF networks. To a lesser degree, adherent platelet-monocyte complexes were also observed. Many of these hetero-aggregates did not appear consistent with direct contact of single platelets to the leukocyte surface, but instead appeared as a dynamic clustering of platelets downstream from leukocytes possibly consistent with VWF net formation on leukocytes (31). The contribution of platelets to post-MI endothelial activation in this study was confirmed by a reduction, but not elimination, of P-selectin and VCAM-1 signal at 21 days in platelet-depleted DKO mice.
Oxidative stress measured by a variety of biomarkers is known to increase after recent MI (32), is known to be greater in the setting of dyslipidemia (33), and represents a pathway by which inflammation and platelet adhesion can self-propagate in a deleterious manner (9). We evaluated the contribution of oxidative stress by treating mice with apocynin, which, among many of its effects, inhibits membrane translocation of the p47phox and gp91phox subunits of Nox (13), and in our experience, has been more effective at reducing adhesion molecule expression than free radical scavenger approaches. Apocynin was found to reduce molecular imaging signal for P-selectin, VCAM-1, VWF-A1, and platelet GPIbα. These data suggest that increased oxidative stress plays an important role in remote endothelial activation after MI. These findings are consistent with known effects of reactive oxygen species to stimulate adhesion molecule expression through the transcription factor nuclear factor-κB and to inhibit proteolytic regulation of VWF (34–36). The suppression of adhesion molecule expression and platelet adhesion with apocynin was associated with partial protection from post-MI accelerated plaque progression in terms of inflammation and necrotic core size.
Although the murine model was selected to reflect human disease based on reproducible plaque development without extreme diet, mice do not necessarily reproduce human condition based on both plaque location and lack of plaque rupture or erosion as the inciting event. It is also important to note that post-MI molecular imaging and plaque assessment were made only for the aorta based on the inability to resolve smaller branch nonculprit arteries and because of the unique distribution of disease in murine models. We did not make any direct measurements of oxidative stress in the different cohorts, largely because of the strength of evidence from previous studies demonstrating that oxidative biomarkers increase after MI and are reduced by apocynin (32,37). There are insufficient data to state that the primary mechanism by which apocynin reduced plaque progression after MI was directly attributable to adhesion molecule expression and platelet adhesion. Instead, we believe that lowering ROS would have pleiotropic effects that would include the endothelial abnormalities that were the focus of this study. Importantly, we do not yet have data revealing the primary inciting factor for remote plaque activation, nor do we have data on how infarct size or duration of ischemia influence the degree of remote plaque activation.
MI leads to remote endothelial activation and abnormal regulation of endothelial-associated and possibly leukocyte-associated VWF (Central Illustration). These processes are associated with enhanced monocyte recruitment, platelet-endothelial adhesion, and acceleration of plaque progression. Interrupting the endogenous vascular production of ROS with the Nox inhibitor apocynin suppresses adverse remote endothelial changes. Our findings help clarify the mechanisms for heightened risk for recurrent events after MI, and reveal potentially modifiable processes. They could also contribute to the mechanistic understanding of the recently described beneficial effects of proinflammatory cytokine inhibition in patients with MI (38).
COMPETENCY IN MEDICAL KNOWLEDGE: Acute atherothrombotic events, such as MI and stroke, increase the risk of ischemic events in nonculprit arteries and other vascular territories for several months. These secondary events are mediated by up-regulation of endothelial inflammatory adhesion molecules and platelet-endothelium interactions that are associated with accelerated plaque inflammation and persist longer in the presence of hyperlipidemia.
TRANSLATIONAL OUTLOOK: Future research should examine inhibition of systemic inflammatory processes that promote endothelial adhesiveness and platelet-endothelium interactions to reduce recurrent ischemic events after MI.
Dr. Moccetti has received support from a grant from the Swiss National Science Foundation. Dr. Ruggeri has received support from National Institutes of Health (NIH) grants HL42846 and HL78784. Dr. López has received support from NIH grants R01-HL091153 and R01-HL11763. Dr. Lindner has received support from NIH grants R01-HL078610, R01-HL130046, and P51-OD011092; and grant 14-14NSBRI1-0025 from the NASA National Space Biomedical Research Institute. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- A disintegrin and metalloprotease with thrombospondin type I repeats-13
- contrast-enhanced ultrasound
- double knockout
- vascular cell adhesion molecule
- von Willebrand factor
- Received February 16, 2018.
- Revision received June 7, 2018.
- Accepted June 10, 2018.
- 2018 American College of Cardiology Foundation
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