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In ischemic tissue, platelets can modulate angiogenesis. The specific factors influencing this function, however, are poorly understood. Here, we characterized the complement anaphylatoxin C5a-mediated activation of C5a receptor 1 (C5aR1) expressed on platelets as a potent regulator of ischemia-driven revascularization. We assessed the relevance of the anaphylatoxin receptor C5aR1 on platelets in patients with coronary artery disease as well as those with peripheral artery disease and used genetic mouse models to characterize its significance for ischemia and growth factor-driven revascularization. The presence of C5aR1-expressing platelets was increased in the hindlimb ischemia model. Ischemia-driven angiogenesis was significantly improved in C5aR1-/- mice but not in C5-/- mice, suggesting a specific role of C5aR1. Experiments using the supernatant of C5a-stimulated platelets suggested a paracrine mechanism of angiogenesis inhibition by platelets by means of antiangiogenic CXC chemokine ligand 4 (CXCL4, PF4). Lineage-specific C5aR1 deletion verified that the secretion of CXCL4 depends on C5aR1 ligation on platelets. Using C5aR1-/-CXCL4-/- mice, we observed no additional effect in the revascularization response, underscoring a strong dependence of CXCL4 secretion on the C5a-C5aR1-axis. We identified a novel mechanism for inhibition of neovascularization via platelet C5aR1, which was mediated by the release of antiangiogenic CXCL4., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Importance: The Global Registry of Acute Coronary Events (GRACE) risk score, a guideline-recommended risk stratification tool for patients presenting with acute coronary syndromes (ACS), does not consider the extent of myocardial injury., Objective: To assess the incremental predictive value of a modified GRACE score incorporating high-sensitivity cardiac troponin (hs-cTn) T at presentation, a surrogate of the extent of myocardial injury., Design, Setting, and Participants: This retrospectively designed longitudinal cohort study examined 3 independent cohorts of 9803 patients with ACS enrolled from September 2009 to December 2017; 2 ACS derivation cohorts (Heidelberg ACS cohort and Newcastle STEMI cohort) and an ACS validation cohort (SPUM-ACS study). The Heidelberg ACS cohort included 2535 and the SPUM-ACS study 4288 consecutive patients presenting with a working diagnosis of ACS. The Newcastle STEMI cohort included 2980 consecutive patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention. Data were analyzed from March to June 2023., Exposures: In-hospital, 30-day, and 1-year mortality risk estimates derived from an updated risk score that incorporates continuous hs-cTn T at presentation (modified GRACE)., Main Outcomes and Measures: The predictive value of continuous hs-cTn T and modified GRACE risk score compared with the original GRACE risk score. Study end points were all-cause mortality during hospitalization and at 30 days and 1 year after the index event., Results: Of 9450 included patients, 7313 (77.4%) were male, and the mean (SD) age at presentation was 64.2 (12.6) years. Using continuous rather than binary hs-cTn T conferred improved discrimination and reclassification compared with the original GRACE score (in-hospital mortality: area under the receiver operating characteristic curve [AUC], 0.835 vs 0.741; continuous net reclassification improvement [NRI], 0.208; 30-day mortality: AUC, 0.828 vs 0.740; NRI, 0.312; 1-year mortality: AUC, 0.785 vs 0.778; NRI, 0.078) in the derivation cohort. These findings were confirmed in the validation cohort. In the pooled population of 9450 patients, modified GRACE risk score showed superior performance compared with the original GRACE risk score in terms of reclassification and discrimination for in-hospital mortality end point (AUC, 0.878 vs 0.780; NRI, 0.097), 30-day mortality end point (AUC, 0.858 vs 0.771; NRI, 0.08), and 1-year mortality end point (AUC, 0.813 vs 0.797; NRI, 0.056)., Conclusions and Relevance: In this study, using continuous rather than binary hs-cTn T at presentation, a proxy of the extent of myocardial injury, in the GRACE risk score improved the mortality risk prediction in patients with ACS.

Although VEGF-B was discovered as a VEGF-A homolog a long time ago, the angiogenic effect of VEGF-B remains poorly understood with limited and diverse findings from different groups. Notwithstanding, drugs that inhibit VEGF-B together with other VEGF family members are being used to treat patients with various neovascular diseases. It is therefore critical to have a better understanding of the angiogenic effect of VEGF-B and the underlying mechanisms. Using comprehensive in vitro and in vivo methods and models, we reveal here for the first time an unexpected and surprising function of VEGF-B as an endogenous inhibitor of angiogenesis by inhibiting the FGF2/FGFR1 pathway when the latter is abundantly expressed. Mechanistically, we unveil that VEGF-B binds to FGFR1, induces FGFR1/VEGFR1 complex formation, and suppresses FGF2-induced Erk activation, and inhibits FGF2-driven angiogenesis and tumor growth. Our work uncovers a previously unrecognized novel function of VEGF-B in tethering the FGF2/FGFR1 pathway. Given the anti-angiogenic nature of VEGF-B under conditions of high FGF2/FGFR1 levels, caution is warranted when modulating VEGF-B activity to treat neovascular diseases., (© 2023. West China Hospital, Sichuan University.)

Background and Aims: Preclinical data suggest that activation of the adaptive immune system is critical for myocardial repair processes in acute myocardial infarction. The aim of the present study was to determine the clinical value of baseline effector T cell chemokine IP-10 blood levels in the acute phase of ST-segment elevation myocardial infarction (STEMI) for the prediction of the left ventricular function changes and cardiovascular outcomes after STEMI., Methods: Serum IP-10 levels were retrospectively quantified in two independent cohorts of STEMI patients undergoing primary percutaneous coronary intervention., Results: We report a biphasic response of the effector T cell trafficking chemokine IP-10 characterized by an initial increase of its serum levels in the acute phase of STEMI followed by a rapid reduction at 90min post reperfusion. Patients at the highest IP-10 tertile presented also with more CD4 effector memory T cells (CD4 T EM cells), but not other T cell subtypes, in blood. In the Newcastle cohort (n=47), patients in the highest IP-10 tertile or CD4 T EM cells at admission exhibited an improved cardiac systolic function 12 weeks after STEMI compared to patients in the lowest IP-10 tertile. In the Heidelberg cohort (n=331), STEMI patients were followed for a median of 540 days for major adverse cardiovascular events (MACE). Patients presenting with higher serum IP-10 levels at admission had a lower risk for MACE after adjustment for traditional risk factors, CRP and high-sensitivity troponin-T levels (highest vs. rest quarters: HR [95% CI]=0.420 [0.218-0.808])., Conclusion: Increased serum levels of IP-10 in the acute phase of STEMI predict a better recovery in cardiac systolic function and less adverse events in patients after STEMI., Competing Interests: MM-H. reports consulting fees for Zoll CMS GmbH, research funding from Roche Diagnostics and BRAHMS Thermo Scientific. NF has received lecture fees from AstraZeneca, Boehringer Ingelheim, Bayer Vital and consulting fees for Boehringer Ingelheim, all of which not related to the subject in this manuscript. DD reports consulting and speaker fees from Bayer Healthcare, Boston Scientific, Daiichi Sankyo, AstraZeneca, and research grants from DFG, DZHK. EG has received honoraria for lectures from AstraZeneca, Daiichi Sankyo and Roche Diagnostics, consulting fees for BRAHMS Deutschland, Roche Diagnostics, AstraZeneca, Daiichi and Novo Nordisk, research funding from Daiichi and Roche Diagnostics. IS receives research grants from Kancera AB and Astra Zaneca. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Sopova, Tual-Chalot, Mueller-Hennessen, Vlachogiannis, Georgiopoulos, Biener, Sachse, Turchinovich, Polycarpou-Schwarz, Spray, Maneta, Bennaceur, Mohammad, Richardson, Gatsiou, Langer, Frey, Stamatelopoulos, Heineke, Duerschmied, Giannitsis, Spyridopoulos and Stellos.)

Platelets are important cellular targets in cardiovascular disease. Based on insights from basic science, translational approaches and clinical studies, a distinguished anti-platelet drug treatment regimen for cardiovascular patients could be established. Furthermore, platelets are increasingly considered as cells mediating effects "beyond thrombosis", including vascular inflammation, tissue remodeling and healing of vascular and tissue lesions. This review has its focus on the functions and interactions of platelets with potential translational and clinical relevance. The role of platelets for the development of atherosclerosis and therapeutic modalities for primary and secondary prevention of atherosclerotic disease are addressed. Furthermore, novel therapeutic options for inhibiting platelet function and the use of platelets in regenerative medicine are considered.

Background: Percutaneous mitral valve repair (PMVR) has evolved to be a standard procedure in suitable patients with mitral regurgitation (MR) not accessible for open surgery. Here, we analyzed the influence of the number and positioning of the clips implanted during the procedure on MR reduction analyzing also sub-collectives of functional and degenerative MR (DMR)., Results: We included 410 patients with severe MR undergoing PMVR using the MitraClip® System. MR and reduction of MR were analyzed by TEE at the beginning and at the end of the PMVR procedure. To specify the clip localization, we sub-divided segment 2 into 3 sub-segments using the segmental classification of the mitral valve., Results: We found an enhanced reduction of MR predominantly in DMR patients who received more than one clip. Implantation of only one clip led to a higher MR reduction in patients with functional MR (FMR) in comparison to patients with DMR. No significant differences concerning pressure gradients could be observed in degenerative MR patients regardless of the number of clips implanted. A deterioration of half a grade of the achieved MR reduction was observed 6 months post-PMVR independent of the number of implanted clips with a better stability in FMR patients, who got 3 clips compared to patients with only one clip., Conclusions: In patients with FMR, after 6 months the reduction of MR was more stable with an increased number of implanted clips, which suggests that this specific patient collective may benefit from a higher number of clips., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Author(s).)

Different types of immune cells are involved in atherogenesis and may act atheroprotective or atheroprogressive. Here, we describe an in vitro approach to analyze CD11c + cells and CD11c + -derived ApoE in atherosclerosis. The major steps include harvesting mouse bone marrow, plating cells in culture dishes, treating them with differentiation factors, and collecting cells after removal of undesirable populations. This protocol can be adapted for CD11c + cells in different contexts, thus, serving as models for different diseases and to analyze cell-specific molecules. For complete details on the use and execution of this protocol, please refer to Sauter et al. (2021)., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Here, we describe an in vivo approach to visualize CD11c + cells in atherosclerosis. In particular, we use a protocol for X-Gal staining of immune cells within atherosclerotic plaques, which can be used as an alternative to analyze plaque composition and cell-specific molecules in atherogenesis. LacZ knockin mice have to be bred to mice carrying the CD11c cre recombinase-both brought onto an ApoE -/- background-to be able to visualize this cell type of interest in the plaques by X-Gal staining. With this approach, different immune cells in atherogenesis can be examined. For complete details on the use and execution of this protocol, please refer to Sauter et al. (2021)., Competing Interests: The authors declare no competing interests., (© 2022.)

Platelets are key mediators of thrombus formation and inflammation during the acute phase of ischaemic stroke. Particularly, the platelet glycoprotein (GP) receptors GPIbα and GPVI have been shown to mediate platelet adhesion and activation in the ischaemic brain. GPIbα and GPVI blockade could reduce infarct volumes and improve functional outcome in mouse models of acute ischaemic stroke, without concomitantly increasing intracerebral haemorrhage. However, the functional role of platelets during long-term stroke recovery has not been elucidated so far. Thus, we here examined the impact of platelet depletion on post-stroke recovery after transient middle cerebral artery occlusion (tMCAO) in adult male mice. Platelet depleting antibodies or isotype control were applied from day 3-28 after tMCAO in mice matched for infarct size. Long-term functional recovery was assessed over the course of 28 days by behavioural testing encompassing motor and sensorimotorical functions, as well as anxiety-like or spontaneous behaviour. Whole brain flow cytometry and light sheet fluorescent microscopy were used to identify resident and infiltrated immune cell types, and to determine the effects of platelet depletion on the cerebral vascular architecture, respectively. We found that delayed platelet depletion does not improve long-term functional outcome in the tMCAO stroke model. Immune cell abundance, the extent of thrombosis and the organisation of the cerebral vasculature were also comparable between platelet-depleted and control mice. Our study demonstrates that, despite their critical role in the acute stroke setting, platelets appear to contribute only marginally to tissue reorganisation and functional recovery at later stroke stages., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Authors.)

P2X receptors belong to a family of cation channel proteins, which respond to extracellular adenosine 5'-triphosphate (ATP). These receptors have gained increasing attention in basic and translational research, as they are central to a variety of important pathophysiological processes such as the modulation of cardiovascular physiology, mediation of nociception, platelet and macrophage activation, or neuronal-glial integration. While P2X1 receptor activation is long known to drive platelet aggregation, P2X7 receptor antagonists have recently been reported to inhibit platelet activation. Considering the role of both P2X receptors and platelet-mediated inflammation in neuronal diseases such as multiple sclerosis, Alzheimer's disease, Parkinson's disease, and stroke, targeting purinergic receptors may provide a valuable novel therapeutic approach in these diseases. Therefore, the present review illuminates the role of platelets and purinergic signaling in these neurological conditions to evaluate potential translational implications.

Platelet activation plays a critical role in thrombosis. Inhibition of platelet activation is a cornerstone in treatment of acute organ ischemia. Platelet ACKR3 surface expression is independently associated with all-cause mortality in CAD patients. In a novel genetic mouse strain, we show that megakaryocyte/platelet-specific deletion of ACKR3 results in enhanced platelet activation and thrombosis in vitro and in vivo. Further, we performed ischemia/reperfusion experiments (transient LAD-ligation and tMCAO) in mice to assess the impact of genetic ACKR3 deficiency in platelets on tissue injury in ischemic myocardium and brain. Loss of platelet ACKR3 enhances tissue injury in ischemic myocardium and brain and aggravates tissue inflammation. Activation of platelet-ACKR3 via specific ACKR3 agonists inhibits platelet activation and thrombus formation and attenuates tissue injury in ischemic myocardium and brain. Here we demonstrate that ACKR3 is a critical regulator of platelet activation, thrombus formation and organ injury following ischemia/reperfusion., (© 2022. The Author(s).)

Mechanisms of innate immunity contribute to inflammation, one of the major underlying causes of atherogenesis and progression of atherosclerotic vessel disease. How immune cells exactly contribute to atherosclerosis and interact with molecules of cholesterol homeostasis is still a matter of intense research. Recent evidence has proposed a potential role of previously underappreciated cell types in this chronic disease including platelets and dendritic cells (DCs). The pathophysiology of atherosclerosis is studied in models with dysfunctional lipid homeostasis and several druggable molecular targets are derived from these models. Specific therapeutic approaches focussing on these immune mechanisms, however, have not been successfully introduced into everyday clinical practice, yet. This review highlights molecular insights into immune processes related to atherosclerosis and potential future translational approaches targeting these molecular mechanisms., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Sauter and Langer.)

Recent evidence suggests interaction of platelets with dendritic cells (DCs), while the molecular mechanisms mediating this heterotypic cell cross-talk are largely unknown. We evaluated the role of integrin Mac-1 (αMβ2, CD11b/CD18) on DCs as a counterreceptor for platelet glycoprotein (GP) Ibα. In a dynamic coincubation model, we observed interaction of human platelets with monocyte-derived DCs, but also that platelet activation induced a sharp increase in heterotypic cell binding. Inhibition of CD11b or GPIbα led to significant reduction of DC adhesion to platelets in vitro independent of GPIIbIIIa, which we confirmed using platelets from Glanzmann thrombasthenia patients and transgenic mouse lines on C57BL/6 background (GPIbα -/- , IL4R-GPIbα-tg, and muMac1 mice). In vivo, inhibition or genetic deletion of CD11b and GPIbα induced a significant reduction of platelet-mediated DC adhesion to the injured arterial wall. Interestingly, only intravascular antiCD11b inhibited DC recruitment, suggesting a dynamic DC-platelet interaction. Indeed, we could show that activated platelets induced CD11b upregulation on Mg 2+ -preactivated DCs, which was related to protein kinase B (Akt) and dependent on P-selectin and P-selectin glycoprotein ligand 1. Importantly, specific pharmacological targeting of the GPIbα-Mac-1 interaction site blocked DC-platelet interaction in vitro and in vivo. These results demonstrate that cross-talk of platelets with DCs is mediated by GPIbα and Mac-1, which is upregulated on DCs by activated platelets in a P-selectin glycoprotein ligand 1-dependent manner., (Copyright © 2022 by The American Association of Immunologists, Inc.)

The brain and spinal cord are immune-privileged organs, but in the disease state protection mechanisms such as the blood brain barrier (BBB) are ineffective or overcome by pathological processes. In neuroinflammatory diseases, microglia cells and other resident immune cells contribute to local vascular inflammation and potentially a systemic inflammatory response taking place in parallel. Microglia cells interact with other cells impacting on the integrity of the BBB and propagate the inflammatory response through the release of inflammatory signals. Here, we discuss the activation and response mechanisms of innate and adaptive immune processes in response to neuroinflammation. Furthermore, the clinical importance of neuroinflammatory mediators and a potential translational relevance of involved mechanisms are addressed also with focus on non-classical immune cells including microglia cells or platelets. As illustrative examples, novel agents such as Anfibatide or Revacept, which result in reduced recruitment and activation of platelets, a subsequently blunted activation of the coagulation cascade and further inflammatory process, demonstrating that mechanisms of neuroinflammation and thrombosis are interconnected and should be further subject to in depth clinical and basic research., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Sun and Langer.)

Atherosclerosis is studied in models with dysfunctional lipid homeostasis-predominantly the ApoE -/- mouse. The role of antigen-presenting cells (APCs) for lipid homeostasis is not clear. Using a LacZ reporter mouse, we showed that CD11c + cells were enriched in aortae of ApoE -/- mice. Systemic long-term depletion of CD11c + cells in ApoE -/- mice resulted in significantly increased plaque formation associated with reduced serum ApoE levels. In CD11c cre+ ApoE fl/fl and Albumin cre+ ApoE fl/fl mice, we could show that ≈70% of ApoE is liver-derived and ≈25% originates from CD11c + cells associated with significantly increased atherosclerotic plaque burden in both strains. Exposure to acLDL promoted cholesterol efflux from CD11c + cells and cell-specific deletion of ApoE resulted in increased inflammation reflected by increased IL-1β serum levels. Our results determined for the first time the level of ApoE originating from CD11c + cells and demonstrated that CD11c + cells ameliorate atherosclerosis by the secretion of ApoE., Competing Interests: The authors declare no competing financial interests., (© 2021 The Author(s).)

Cardiovascular diseases (CVD) constitute the main cause of death worldwide. Both inflammation and oxidative stress have been reported to be involved in the progress of CVD. It is well known that generation of oxidative stress during the course of CVD is involved in tissue damage and inflammation, causing deleterious effects such as hypertension, dysfunctional metabolism, endothelial dysfunction, stroke, and myocardial infarction. Remarkably, natural antioxidant strategies have been increasingly discovered and are subject to current scientific investigations. Here, we addressed the activation of immune cells in the context of ROS production, as well as how their interaction with other cellular players and further (immune) mediators contribute to metabolic and cardiovascular disorders. We also highlight how a dysregulated complement system contributes to immune imbalance and tissue damage in the context of increases oxidative stress. Additionally, modulation of hypothalamic oxidative stress is discussed, which may offer novel treatment strategies for type-2 diabetes and obesity. Together, we provide new perspectives on therapy strategies for CVD caused by oxidative stress, with a focus on oxidative stress.

A mutual relationship exists between immune activation and mechanisms of thrombus formation. In particular, elements of the innate immune response such as the complement system can modulate platelet activation and subsequently thrombus formation. Several components of the complement system including C3 or the membrane attack complex have been reported to be associated with platelets and become functionally active in the micromilieu of platelet activation. The exact mechanisms how this interplay is regulated and its consequences for tissue inflammation, damage or recovery remain to be defined. This review addresses the current state of knowledge on this topic and puts it into context with diseases featuring both thrombosis and complement activation. LINKED ARTICLES: This article is part of a themed issue on Canonical and non-canonical functions of the complement system in health and disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.14/issuetoc., (© 2021 The British Pharmacological Society.)

Platelets contribute to the regulation of tissue neovascularization, although the specific factors underlying this function are unknown. Here, we identified the complement anaphylatoxin C5a-mediated activation of C5a receptor 1 (C5aR1) on platelets as a negative regulatory mechanism of vessel formation. We showed that platelets expressing C5aR1 exert an inhibitory effect on endothelial cell functions such as migration and 2D and 3D tube formation. Growth factor- and hypoxia-driven vascularization was markedly increased in C5ar1 -/- mice. Platelet-specific deletion of C5aR1 resulted in a proangiogenic phenotype with increased collateralization, capillarization and improved pericyte coverage. Mechanistically, we found that C5a induced preferential release of CXC chemokine ligand 4 (CXCL4, PF4) from platelets as an important antiangiogenic paracrine effector molecule. Interfering with the C5aR1-CXCL4 axis reversed the antiangiogenic effect of platelets both in vitro and in vivo.In conclusion, we identified a mechanism for the control of tissue neovascularization through C5a/C5aR1 axis activation in platelets and subsequent induction of the antiangiogenic factor CXCL4.

Aims: The aim of this meta-analysis was to compare general anaesthesia (GA) and deep sedation (DS) with regard to safety and length of intensive care unit (ICU) stay in patients undergoing percutaneous edge-to-edge mitral valve repair (PMVR)., Methods and Results: Four studies comparing GA and DS in patients undergoing PMVR were included in an individual patient data meta-analysis. Data were pooled after multiple imputation. The composite safety endpoint of all-cause death, stroke, pneumonia, or major to life-threatening bleeding occurred in 87 of 626 (13.9%) patients with no difference between patients treated with DS as compared to GA (56 and 31 events in 420 and 206 patients, respectively). In this regard, the odds ratio (OR) was 1.27 (95% confidence interval [CI]: 0.78 to 2.09; p=0.338) and 1.26 (95% CI: 0.49 to 3.22; p=0.496) following the one-stage and two-stage approach, respectively. Length of ICU stay was longer after GA as compared to DS (ratio of days 3.08, 95% CI: 2.18 to 4.36, p<0.001, and 2.88, 95% CI: 1.45 to 5.73, p=0.016, following the one-stage and two-stage approach, respectively)., Conclusions: Both DS and GA might offer a similar safety profile. However, ICU stay seems to be shorter after DS.

Beyond platelets function in hemostasis, there is emerging evidence to suggest that platelets contribute crucially to inflammation and immune responses. Therefore, considering the detrimental role of inflammatory conditions in severe neurological disorders such as multiple sclerosis or stroke, this review outlines platelets involvement in neuroinflammation. For this, distinct mechanisms of platelet-mediated thrombosis and inflammation are portrayed, focusing on the interaction of platelet receptors with other immune cells as well as brain endothelial cells. Furthermore, we draw attention to the intimate interplay between platelets and the complement system as well as between platelets and plasmatic coagulation factors in the course of neuroinflammation. Following the thorough exposition of preclinical approaches which aim at ameliorating disease severity after inducing experimental autoimmune encephalomyelitis (a counterpart of multiple sclerosis in mice) or brain ischemia-reperfusion injury, the clinical relevance of platelet-mediated neuroinflammation is addressed. Thus, current as well as future propitious translational and clinical strategies for the treatment of neuro-inflammatory diseases by affecting platelet function are illustrated, emphasizing that targeting platelet-mediated neuroinflammation could become an efficient adjunct therapy to mitigate disease severity of multiple sclerosis or stroke associated brain injury., (Copyright © 2020 Rawish, Nording, Münte and Langer.)

Cardiovascular disease remains the main cause of death worldwide. For this reason, strategies for the primary prevention of atherosclerosis and atherosclerosis-related pathologies like stroke or myocardial infarction are needed. Platelets are key players of atherosclerosis-related vascular thrombotic pathologies and their role as targets in secondary prevention of atherosclerosis-related complications is uncontested. However, platelets also play an important role in the initiation and progression of atherosclerosis. Currently, though, there is no generally valid recommendation for the use of antiplatelet therapy in primary prevention of cardiovascular disease. Recent clinical studies have shown that the benefit from antiplatelet therapy in primary prevention is counteracted by the entailed bleeding risk. This review addresses the important role platelets play in initiating and sustaining vascular inflammation, which drives atherosclerosis. Specifically, platelet-lipid interactions as well as platelet-endothelium interactions in the context of atherosclerosis are illustrated. We also depict how platelets help recruit immune cells like monocytes, neutrophils or dendritic cells to the subendothelial space. Finally, we portray the role of complement and platelets in atherosclerosis. Platelets appear to act as mediators of tissue homeostasis and may also modulate the microenvironment of the atherosclerotic plaque. Overall, this review addresses the role of platelets in atherosclerosis with particular focus on potential targets for pharmacological interventions into platelet functions distinct from aggregation. By eliminating the bleeding risk of antiplatelet therapy, platelets are likely to regain a role in primary prevention of cardiovascular disease., (Copyright © 2020. Published by Elsevier B.V.)

Key Points: The Anrep effect represents the alteration of left ventricular (LV) contractility to acutely enhanced afterload in a few seconds, thereby preserving stroke volume (SV) at constant preload. As a result of the missing preload stretch in our model, the Anrep effect differs from the slow force response and has a different mechanism. The Anrep effect demonstrated two different phases. First, the sudden increased afterload was momentary equilibrated by the enhanced LV contractility as a result of higher power strokes of strongly-bound myosin cross-bridges. Second, the slightly delayed recovery of SV is perhaps dependent on Ca 2+ /calmodulin-dependent protein kinase II activation caused by oxidation and myofilament phosphorylation (cardiac myosin-binding protein-C, myosin light chain 2), maximizing the recruitment of available strongly-bound myosin cross-bridges. Short-lived oxidative stress might present a new facet of subcellular signalling with respect to cardiovascular regulation. Relevance for human physiology was demonstrated by echocardiography disclosing the Anrep effect in humans during handgrip exercise., Abstract: The present study investigated whether oxidative stress and Ca 2+ /calmodulin-dependent protein kinase II (CaMKII) activity are involved in triggering the Anrep effect. LV pressure-volume (PV) analyses of isolated, preload controlled working hearts were performed at two afterload levels (60 and 100 mmHg) in C57BL/6N wild-type (WT) and CaMKII-double knockout mice (DKO CaMKII ). In snap-frozen WT hearts, force-pCa relationship, H 2 O 2 generation, CaMKII oxidation and phosphorylation of myofilament and Ca 2+ handling proteins were assessed. Acutely raised afterload showed significantly increased wall stress, H 2 O 2 generation and LV contractility in the PV diagram with an initial decrease and recovery of stroke volume, whereas end-diastolic pressure and volume, as well as heart rate, remained constant. Afterload induced increase in LV contractility was blunted in DKO CaMKII -hearts. Force development of single WT cardiomyocytes was greater with elevated afterload at submaximal Ca 2+ concentration and associated with increases in CaMKII oxidation and phosphorylation of cardiac-myosin binding protein-C, myosin light chain and Ca 2+ handling proteins. CaMKII activity is involved in the regulation of the Anrep effect and associates with stimulation of oxidative stress, presumably starting a cascade of CaMKII oxidation with downstream phosphorylation of myofilament and Ca 2+ handling proteins. These mechanisms improve LV inotropy and preserve stroke volume within few seconds., (© 2020 The Authors. The Journal of Physiology © 2020 The Physiological Society.)

Very few reports exist on serious cardiac complications associated with intake of serotonin-noradrenaline reuptake inhibitors. This paper describes and discusses the case of a patient who ingested a dose of 17.5 g venlafaxine. She developed a full serotonergic syndrome leading to multi-organ failure, including refractory cardiovascular shock, which was managed by early implantation of an extracorporeal life support (ECLS) system as a bridging strategy. This intervention was successful and resulted in full recovery of the patient., (© 2020 Christoph Marquetand, Harald F. Langer, Jan Philipp Klein, Tobias Graf, published by Sciendo.)

Myocardial ischemia is one of the leading health problems worldwide. Therapy consists of the restitution of coronary perfusion which is followed by myocardial inflammation. Platelet-neutrophil interaction is a crucial process during inflammation, yet its consequences are not fully understood. Here, we show that platelet-neutrophil complexes (PNCs) are increased in patients with acute myocardial infarction and that this is associated with increased levels of neuronal guidance protein semaphorin 7A (SEMA7A). To investigate this further, we injected WT animals with Sema7a and found increased infarct size with increased numbers of PNCs. Experiments in genetically modified animals identify Sema7a on red blood cells to be crucial for this condition. Further studies revealed that Sema7a interacts with the platelet receptor glycoprotein Ib (GPIb). Treatment with anti-Sema7a antibody protected from myocardial tissue injury. In summary, we show that Sema7a binds to platelet GPIb and enhances platelet thrombo-inflammatory activity, aggravating post-ischemic myocardial tissue injury.

Background: Mitral regurgitation (MR) has a severe impact on hemodynamics and induces severe structural changes in the left atrium. Atrial remodeling is known to alter excitability and conduction in the atrium facilitating atrial fibrillation and atrial flutter. PMVR is a feasible and highly effective procedure to reduce MR in high-risk patients, which are likely to suffer from atrial rhythm disturbances. So far, electroanatomical changes after PMVR have not been studied., Hypothesis: In the current study, we investigated changes in surface electrocardiograms (ECGs) of patients undergoing PMVR for reduction of MR., Methods: We evaluated 104 surface ECGs from patients in sinus rhythm undergoing PMVR. P wave duration, P wave amplitude, PR interval, QRS duration, QRS axis, and QT interval were evaluated before and after PMVR and at follow-up., Results: We found no changes in QRS duration, QRS axis, and QT interval after successful PMVR. However, P wave duration, amplitude, and PR interval were significantly decreased after reduction of MR through PMVR (P < .05, respectively)., Conclusion: The data we provide offers insight into changes in atrial conduction after reduction of MR using PMVR in patients with sinus rhythm., (© 2019 The Authors. Clinical Cardiology published by Wiley Periodicals, Inc.)

Introduction: In this study, we evaluated right ventricular (RV) function before and after percutaneous mitral valve repair (PMVR) using conventional echocardiographic parameters and novel 3DE data sets acquired prior to and directly after the procedure., Patients and Methods: Observational study on 45 patients undergoing PMVR at an university hospital., Results: In the overall collective, the 3D RV-EF before and after PMVR showed no significant change (p = 0.16). While there was a significant increase of the fractional area change (FAC, from 23 [19-29] % to 28 [24-33] %, p = 0.001), no significant change of the tricuspid annular plane systolic excursion (TAPSE, from 17 ± 6 mm to 18 ± 5 mm (standard deviation), p = 0.33) was observed. Regarding patients with a reduced RV-EF (< 35%), a significant RV-EF improvement was observed (from 27 [23-34] % to 32.5 [30-39] % (p = 0.001). 71.4% of patients had an improved clinical outcome (improvement in 6-minute walk test and/or improvement in NYHA class of more than one grade), whereas clinical outcome did not improve in 28.6% of patients. Using univariate logistic regression analysis, the post-PMVR RV-EF (OR 1.15: 95% CI 1.02-1.29; p = 0.02) and the change in RV-EF (OR 1.13: 95% CI 1.02-1.25; p = 0.02) were significant predictors for improved clinical outcome at 6 months follow up., Conclusion: Thus, RV function may be an important non-invasive parameter to add to the predictive parameters indicating a potential clinical benefit from treatment of severe mitral regurgitation using PMVR., Competing Interests: Dr. H. F. Langer and Dr. P. Seizer were reimbursed for PMVR training courses by Abbott Vascular, otherwise we have no potential conflict of interest to declare.

Besides mediating hemostatic functions, platelets are increasingly recognized as important players of inflammation. Data from experiments in mice and men revealed various intersection points between thrombosis, hemostasis, and inflammation, which are addressed and discussed in this review in detail. One such example is the intrinsic coagulation cascade that is initiated after platelet activation thereby further propagating and re-enforcing wound healing or thrombus formation but also contributing to the pathophysiology of severe diseases. FXII of the intrinsic pathway connects platelet activation with the coagulation cascade during immune reactions. It can activate the contact system thereby either creating an inflammatory state or accelerating inflammation. Recent insights into platelet biology could show that platelets are equipped with complement receptors. Platelets are important for tissue remodeling after injury has been inflicted to the endothelial barrier and to the subendothelial tissue. Thus, platelets are increasingly recognized as more than just cells relevant for bleeding arrest. Future insights into platelet biology are to be expected. This research will potentially offer novel opportunities for therapeutic intervention in diseases featuring platelet abundance.

Background This study analyzed the effects on long-term outcome of residual mitral regurgitation ( MR ) and mean mitral valve pressure gradient ( MVPG ) after percutaneous edge-to-edge mitral valve repair using the MitraClip system. Methods and Results Two hundred fifty-five patients who underwent percutaneous edge-to-edge mitral valve repair were analyzed. Kaplan-Meier and Cox regression analyses were performed to evaluate the impact of residual MR and MVPG on clinical outcome. A combined clinical end point (all-cause mortality, MV surgery, redo procedure, implantation of a left ventricular assist device) was used. After percutaneous edge-to-edge mitral valve repair, mean MVPG increased from 1.6±1.0 to 3.1±1.5 mm Hg ( P<0.001). Reduction of MR severity to ≤2+ postintervention was achieved in 98.4% of all patients. In the overall patient cohort, residual MR was predictive of the combined end point while elevated MVPG >4.4 mm Hg was not according to Kaplan-Meier and Cox regression analyses. We then analyzed the cohort with degenerative and that with functional MR separately to account for these different entities. In the cohort with degenerative MR , elevated MVPG was associated with increased occurrence of the primary end point, whereas this was not observed in the cohort with functional MR . Conclusions MVPG >4.4 mm Hg after MitraClip implantation was predictive of clinical outcome in the patient cohort with degenerative MR . In the patient cohort with functional MR , MVPG >4.4 mm Hg was not associated with increased clinical events.

Background: Right heart failure remains a major cause of morbidity and mortality after left ventricular assist device (LVAD) implantation. Multiple 2D echocardiography derived parameters are associated with right ventricular failure (RV failure), but none of them has been proven to be a reliable predictor to date. We hypothesized that novel 3D-echocardiography (3DE) based parameters are associated with RV failure and predict long term outcome in patients undergoing LVAD implantation., Methods: This single-center study retrospectively enrolled 26 patients undergoing continuous-flow LVAD implantation. RV failure was defined as prolonged inotropic support for >14 days after LVAD implantation or consecutive implantation of a right ventricular assist device. Based on transesophageal 3DE datasets acquired prior to surgery right ventricular size, ejection fraction and longitudinal strains were calculated., Results: The overall RV failure rate was 19.2%. Patients suffering from RV failure had a significantly impaired 3D-right ventricular ejection fraction (3D-RVEF; 28 ± 2% vs. 19 ± 3%, p = 0.0145) and 3D derived RV free wall longitudinal strain (3D-RV-fws; -13.2 ± 0.97% vs. -6.4 ± 1.98%; p = 0.0056) when compared to patients without RV failure. ROC analysis for 3D-RV-fws (AUC 0.914) and 3D-RVEF (AUC 0.876) showed high discriminative capabilities in regard to detection of RV failure. Kaplan-Meier analysis showed an improved long-term survival of patients with a 3D-RV-fws <-11.9%., Conclusions: 3D-echocardiography derived RV ejection fraction and RV free wall strain are associated with right ventricular failure and long term outcome in patients undergoing LVAD implantation. These parameters have the potential to be future predictors for right heart failure in LVAD surgery., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In recent years, various studies have increasingly explained platelet functions not only in their central role as a regulator in cellular hemostasis and coagulation. In fact, there is growing evidence that under specific conditions, platelets act as a mediator between the vascular system, hemostasis, and the immune system. Therefore, they are essential in many processes involved in tissue remodeling and tissue reorganization after injury or inflammatory responses. These processes include the promotion of inflammatory processes, the contribution to innate and adaptive immune responses during bacterial and viral infections, the modulation of angiogenesis, and the regulation of cell apoptosis in steady-state tissue homeostasis or after tissue breakdown. All in all platelets may contribute to the control of tissue homeostasis much more than generally assumed. This review summarizes the current knowledge of platelets as part of the tissue remodeling network and seeks to provide possible translational implications for clinical therapy.

Platelets are known to be central regulators of haemostasis, inflammation and immune response. Formed by megakaryocytes in the bone marrow and the lungs, platelets express a broad range of adhesion receptors and release cytokines and platelet microparticles which enable them to interact with both immune cells and pathogens. In bacterial and viral infections, thrombophilia and thrombocytopenia are commonly seen symptoms, indicating the close relationship between haemostasis and immune defence. Indeed, platelets contribute both directly and via immune mediation to pathogen clearance. In sterile inflammation, a pathogen-free process which is often triggered by cell necrosis and autoimmune reactions, platelets are also of central importance. Recently, platelet inflammasome has been extensively studied in this context. Both sterile inflammation and infection are affected by the interactions of platelets and innate immunity, notably the complement system. Although the general elements of this interplay have been known for long, more and more insights into disease-specific mechanisms could be gained recently. This review gives an outline of the current findings in the field of platelet-immune cell interactions and points out possible implications for clinical therapy., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (Georg Thieme Verlag KG Stuttgart · New York.)

Background: Patients after transcatheter aortic valve replacement (TAVR) and persistent severe mitral regurgitation (MR) are increasingly treated with percutaneous edge-to-edge mitral valve repair (PMVR). The impact of a former TAVR on PMVR procedures is not clear., Methods and Results: We retrospectively analyzed 332 patients undergoing PMVR using the MitraClip system with respect to procedural and clinical outcome. 21 of these 332 patients underwent TAVR before PMVR. Intra-procedural transthoracic (TTE) and transesophageal echocardiograms (TEE) immediately before and after clip implantation as well as invasive hemodynamic measurements were evaluated. At baseline, we found a significantly smaller mitral valve anterior-posterior diameter in the TAVR cohort (p < 0.001). A reduction of MR by at least three grades was achieved in a smaller fraction in the TAVR cohort as compared to the cohort with a native aortic valve (p = 0.02). Accordingly, we observed a smaller post-procedural cardiac output in the TAVR cohort (p = 0.02)., Conclusion: PMVR in patients who had a TAVR before, is associated with altered MR anatomy before and a reduced improvement of MR after the procedure. Future larger and prospective studies will have to determine, whether a previous TAVR influences long-term clinical outcome of patients undergoing PMVR., Competing Interests: The authors have declared that no competing interests exist.

Background: Platelets have distinct roles in the vascular system in that they are the major mediator of thrombosis, critical for restoration of tissue integrity, and players in vascular inflammatory conditions. In close spatiotemporal proximity, the complement system acts as the first line of defense against invading microorganisms and is a key mediator of inflammation. Whereas the fluid phase cross-talk between the complement and coagulation systems is well appreciated, the understanding of the pathophysiological implications of such interactions is still scant., Methods: We analyzed coexpression of the anaphylatoxin receptor C3aR with activated glycoprotein IIb/IIIa on platelets of 501 patients with coronary artery disease using flow cytometry; detected C3aR expression in human or murine specimen by polymerase chain reaction, immunofluorescence, Western blotting, or flow cytometry; and examined the importance of platelet C3aR by various in vitro platelet function tests, in vivo bleeding time, and intravital microscopy. The pathophysiological relevance of C3aR was scrutinized with the use of disease models of myocardial infarction and stroke. To approach underlying molecular mechanisms, we identified the platelet small GTPase Rap1b using nanoscale liquid chromatography coupled to tandem mass spectrometry., Results: We found a strong positive correlation of platelet complement C3aR expression with activated glycoprotein IIb/IIIa in patients with coronary artery disease and coexpression of C3aR with glycoprotein IIb/IIIa in thrombi obtained from patients with myocardial infarction. Our results demonstrate that the C3a/C3aR axis on platelets regulates distinct steps of thrombus formation such as platelet adhesion, spreading, and Ca 2+ influx. Using C3aR -/- mice or C3 -/- mice with reinjection of C3a, we uncovered that the complement activation fragment C3a regulates bleeding time after tail injury and thrombosis. Notably, C3aR -/- mice were less prone to experimental stroke and myocardial infarction. Furthermore, reconstitution of C3aR -/- mice with C3aR +/+ platelets and platelet depletion experiments demonstrated that the observed effects on thrombosis, myocardial infarction, and stroke were specifically caused by platelet C3aR. Mechanistically, C3aR-mediated signaling regulates the activation of Rap1b and thereby bleeding arrest after injury and in vivo thrombus formation., Conclusions: Overall, our findings uncover a novel function of the anaphylatoxin C3a for platelet function and thrombus formation, highlighting a detrimental role of imbalanced complement activation in cardiovascular diseases.

Aim: The aim of this study is to analyse the prognostic value of complement anaphylatoxin receptors in patients with non-ischaemic cardiomyopathy undergoing endomyocardial biopsy., Methods and Results: In 102 patients (72.5% male patients, median age 54 years) with non-ischaemic cardiomyopathy, myocardial expression of C3aR was assessed among other parameters. The primary study endpoint was a composite of death, heart transplantation, heart failure-related re-hospitalization, and deterioration of left ventricular ejection fraction within a mean follow-up of 11.9 months. The number of cells, which stained positive for C3aR, was significantly increased in patients with inflammatory compared with non-inflammatory cardiomyopathy (1.75 ± 0.31 cells in inflammatory cardiomyopathy vs. 0.94 ± 0.26 in non-inflammatory cardiomyopathy, P = 0.049). Subsequently, positive expression for C3aR was judged based on a semi-quantitative scoring system. Significantly, more patients with positive MHCII and CD68 expression showed an increased number of C3aR-positive cells. C3aR expression based on this score was more pronounced in patients with human herpesvirus 6 viral genome detection. Kaplan-Meier curves illustrate that the C3aR-negative group reached the primary endpoint significantly more often (mean follow-up 11.9 months, log rank 5.963, P = 0.015). Lack of C3aR expression was a strong independent predictor for the primary endpoint in Cox regression analysis [hazard ratio 0.46 (0.26-0.82, P = 0.009)]., Conclusions: C3aR-positive cells are found more often in patients with inflammatory cardiomyopathy. The relevance of C3aR-positive cells in patients with non-ischaemic cardiomyopathy should be further evaluated as potential predictors or modulators of adverse cardiac remodelling, the substrate of progressive heart failure., (© 2018 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology.)

Aims: Improved mitral valve leaflet coaptation with consecutive reduction of mitral regurgitation (MR) is a central goal of percutaneous mitral valve repair (PMVR) with the MitraClip® system. As influences of PMVR on mitral valve geometry have been suggested before, we examined the effect of the procedure on mitral annular size in relation to procedural outcome., Methods and Results: Geometry of the mitral valve annulus was evaluated in 183 patients undergoing PMVR using echocardiography before and after the procedure and at follow-up. Mitral valve annular anterior-posterior (ap) diameter decreased from 34.0 ± 4.3 to 31.3 ± 4.9 mm (P < 0.001), and medio-lateral (ml) diameter from 33.2 ± 4.8 to 32.4 ± 4.9 mm (P < 0.001). Accordingly, we observed an increase in MV leaflet coaptation after PMVR. The reduction of mitral valve ap diameter showed a significant inverse correlation with residual MR. Importantly, the reduction of mitral valve ap diameter persisted at follow-up (31.3 ± 4.9 mm post PMVR, 28.4 ± 5.3 mm at follow-up)., Conclusion: This study demonstrates mechanical approximation of both mitral valve annulus edges with improved mitral valve annular coaptation by PMVR using the MitraClip® system, which correlates with residual MR in patients with MR.

The complement system is a versatile part of our immune system. Various intersection points of complement with other cells and molecules of the immune response are well described. Platelets are classically conceived as cells of hemostasis. In recent years, however, several functions of platelets "beyond thrombosis" were discovered. This review depicts the crosstalk of platelets with components of the immune system in the context of thrombo-inflammation. In particular, the various ways, in which platelets interact with the complement system, are illustrated. Platelets cannot only aggravate vascular inflammation and cardiovascular diseases, but they also contribute to organ remodeling and tissue homeostasis. Here, we portray the role of complement factors associated with platelet activation in tissue remodeling. Importantly, the clinical relevance of this platelet-complement crosstalk is addressed. A focus lies on thrombo-inflammatory disorders, other diseases with thrombo-embolic mechanisms or complications, but also autoimmune diseases. Finally, we draw attention to the growing body of evidence on the role of complement-platelet crosstalk in cardiovascular diseases. For future clinical, translational and basic science approaches, this crosstalk may prove a fruitful area of research in order to procure novel therapeutic and diagnostic targets in cardiovascular medicine and previously less addressed diseases featuring a platelet-complement axis., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Percutaneous edge-to-edge mitral valve repair (PMVR) has become an established treatment option for mitral regurgitation in patients not eligible for surgical repair. Currently, most procedures are performed under general anesthesia (GA). An increasing number of centers, however, are performing the procedure under deep sedation (DS). Here, we compared patients undergoing PMVR with GA or DS., Methods and Results: A total of 271 consecutive patients underwent PMVR at our institution between May 2014 and December 2016. Seventy-two procedures were performed under GA and 199 procedures under DS. We observed that in the DS group, doses of propofol (743±228 mg for GA versus 369±230 mg for DS, P <0.001) and norepinephrine (1.1±1.6 mg for GA versus 0.2±0.3 mg for DS, P <0.001) were significantly lower. Procedure time, fluoroscopy time, and dose area product were significantly higher in the GA group. There was no significant difference between GA and DS with respect to overall bleeding complications, postinterventional pneumonia (4% for GA versus 5% for DS), or C-reactive protein levels (361±351 nmol/L for GA versus 278±239 nmol/L for DS). Significantly fewer patients with DS needed a postinterventional stay in the intensive care unit (96% for GA versus 19% for DS, P <0.001). Importantly, there was no significant difference between DS and GA regarding intrahospital or 6-month mortality., Conclusions: DS for PMVR is safe and feasible. No disadvantages with respect to procedural outcome or complications in comparison to GA were observed. Applying DS may simplify the PMVR procedure., (© 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.)

Elevated levels of circulating pro-inflammatory biomarkers in patients with both ischaemic and non-ischaemic heart failure (HF) correlate with disease severity and prognosis. Experimental studies have shown activation of immune response mechanisms in the heart to provoke cardiac adverse remodelling and cause left ventricular dysfunction. Consequently, most of the clinical trials targeting elements of the immune response in HF attempted to modulate the inflammatory response. Surprisingly, clinical studies targeting immune effectors were either neutral or even increased pre-specified clinical endpoints, and some studies resulted in worsening of HF. This review discusses immune mediators involved in the pathogenesis and progression of HF and potential therapeutic applications targeting inflammation in HF. Besides more obvious settings featuring immune activation such as inflammatory or ischaemic cardiomyopathy, the relevance of immune activation in acute or chronic HF of other origins, including volume overload or valvular heart disease, is highlighted. Understanding how cell-specific and molecular mechanisms of the immune response interfere with cardiac remodelling in HF may open new avenues to design biomarkers or druggable targets., (© 2017 The Authors. European Journal of Heart Failure © 2017 European Society of Cardiology.)

Many pathophysiological processes are associated with proliferation, migration or death of distinct cell populations. Monitoring specific cell types and their progeny in a non-invasive, longitudinal and quantitative manner is still challenging. Here we show a novel cell-tracking system that combines Cre/lox-assisted cell fate mapping with a thymidine kinase (sr39tk) reporter gene for cell detection by positron emission tomography (PET). We generate Rosa26-mT/sr39tk PET reporter mice and induce sr39tk expression in platelets, T lymphocytes or cardiomyocytes. As proof of concept, we demonstrate that our mouse model permits longitudinal PET imaging and quantification of T-cell homing during inflammation and cardiomyocyte viability after myocardial infarction. Moreover, Rosa26-mT/sr39tk mice are useful for whole-body characterization of transgenic Cre mice and to detect previously unknown Cre activity. We anticipate that the Cre-switchable PET reporter mice will be broadly applicable for non-invasive long-term tracking of selected cell populations in vivo.Non-invasive cell tracking is a powerful method to visualize cells in vivo under physiological and pathophysiological conditions. Here Thunemann et al. generate a mouse model for in vivo tracking and quantification of specific cell types by combining a PET reporter gene with Cre-dependent activation that can be exploited for any cell population for which a Cre mouse line is available.

Background: Platelet membrane glycoprotein receptors mediate thrombus formation. GP Ia/IIa is an essential platelet integrin receptor. Single-nucleotide polymorphisms (SNPs) of the GP Ia/IIa gene alter GP Ia/IIa expression; however, their influence on cardiovascular disease remains unclear. This study aimed to investigate the effect of the GP Ia/IIa SNPs rs1126643 and rs1062535 on clinical outcomes in a large collective including high-risk patients with cardiovascular disease., Methods and Results: GP Ia SNP analysis was performed in 943 patients with symptomatic coronary artery disease. All patients were tracked for all-cause death, myocardial infarction, and ischemic stroke for 360 days. Homozygous carriers of the minor allele showed significantly worse event-free survival when compared with major allele carriers in the complete collective as well as in the subset of high-risk patients (carrying all of the following three risk factors: diabetes type II, hypertension, and hyperlipidemia). There was no significant difference in the subset of low-risk patients (carrying none of the three risk factors)., Conclusions: GPla SNPs are associated with cardiovascular prognosis especially in high-risk patients. Identification of GPIa SNPs is of importance to tailor therapies in patients at already high cardiovascular risk.

Background: Successful percutaneous mitral valve repair (PMVR) in patients with severe mitral regurgitation (MR) causes changes in hemodynamics. Echocardiographic calculation of cardiac output (CO) has not been evaluated in the setting of PMVR, so far. Here we evaluated hemodynamics before and after PMVR with the MitraClip system using pulmonary artery catheterization, transthoracic (TTE) and transesophageal (TEE) echocardiography., Methods: 101 patients with severe MR not eligible for conventional surgery underwent PMVR. Hemodynamic parameters were determined during and after the intervention. We evaluated changes in CO and pulmonary artery systolic pressure before and after PMVR. CO was determined with invasive parameters using the Fick method (COi) and by a combination of TTE and TEE (COe)., Results: All patients had successful clip implantation, which was associated with increased COi (from 4.6±1.4l/min to 5.4±1.6l/min, p<0.001). Furthermore, pulmonary artery systolic pressure (PASP) showed a significant decrease after PMVR (47.6±16.1 before, 44.7±15.5mmHg after, p=0.01). In accordance with invasive measurements, COe increased significantly (COe from 4.3±1.7l/min to 4.8±1.7l/min, p=0.003). Comparing both methods to calculate CO, we observed good agreement between COi and COe using Bland Altman plots., Conclusions: CO increased significantly after PMVR as determined by echocardiography based and invasive calculation of hemodynamics during PMVR. COe shows good agreement with COi before and after the intervention and, thus, represents a potential non-invasive method to determine CO in patients with MR not accessible by conventional surgery., (Copyright © 2017 Elsevier B.V. All rights reserved.)