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Background and Aims Glycoprotein VI (GPVI) is a platelet collagen/fibrin(ogen) receptor and an emerging pharmacological target for the treatment of thrombotic and thrombo-inflammatory diseases, notably ischaemic stroke. A first anti-human GPVI (hGPVI) antibody Fab-fragment (ACT017/glenzocimab, K D: 4.1 nM) recently passed a clinical phase 1b/2a study in patients with acute ischaemic stroke and was found to be well tolerated, safe, and potentially beneficial. In this study, a novel humanized anti-GPVI antibody Fab-fragment (EMA601; K D: 0.195 nM) was developed that inhibits hGPVI function with very high potency in vitro and in vivo. Methods Fab-fragments of the mouse anti-hGPVI IgG Emf6.1 were tested for functional GPVI inhibition in human platelets and in hGPVI expressing (hGP6tg/tg) mouse platelets. The in vivo effect of Emf6.1Fab was assessed in a tail bleeding assay, an arterial thrombosis model and the transient middle cerebral artery occlusion (tMCAO) model of ischaemic stroke. Using complementary-determining region grafting, a humanized version of Emf6.1Fab (EMA601) was generated. Emf6.1Fab/EMA601 interaction with hGPVI was mapped in array format and kinetics and quantified by bio-layer interferometry. Results Emf6.1Fab (K D: 0.427 nM) blocked GPVI function in human and hGP6tg/tg mouse platelets in multiple assays in vitro at concentrations ≥5 µg/mL. Emf6.1Fab (4 mg/kg)-treated hGP6tg/tg mice showed potent hGPVI inhibition ex vivo and were profoundly protected from arterial thrombosis as well as from cerebral infarct growth after tMCAO, whereas tail-bleeding times remained unaffected. Emf6.1Fab binds to a so far undescribed membrane proximal epitope in GPVI. The humanized variant EMA601 displayed further increased affinity for hGPVI (K D: 0.195 nM) and fully inhibited the receptor at 0.5 µg/mL, corresponding to a >50-fold potency compared with ACT017. Conclusions EMA601 is a conceptually novel and promising anti-platelet agent to efficiently prevent or treat arterial thrombosis and thrombo-inflammatory pathologies in humans at risk. [ABSTRACT FROM AUTHOR]

Background: Severe acute ischemic stroke (AIS) is mainly caused by thromboembolism originating from symptomatic carotid artery (ICA) stenosis or in the heart due to atrial fibrillation. Glycoprotein VI (GPVI), a principal platelet receptor, facilitates platelet adherence and thrombus formation at sites of vascular injury such as symptomatic ICA stenosis. The shedding of GPVI from the platelet surface releases soluble GPVI (sGPVI) into the circulation. Here, we aimed to determine whether sGPVI can serve as a local biomarker to differentiate between local atherosclerotic and systemic cardiac thromboembolism in AIS. Methods: We conducted a cohort study involving 105 patients undergoing emergency endovascular thrombectomy (EVT) for anterior circulation stroke. First, sGPVI concentrations were measured in systemic arterial plasma samples collected at the ipsilateral ICA level, including groups with significantly (≥50%) stenotic and non-stenotic arteries. A second sample, taken from the intracerebral pial circulation, was used to assess GPVI shedding locally within the ischemic brain. Results: Our analysis revealed no significant increase in systemic sGPVI levels in patients with symptomatic ≥ 50% ICA stenosis (3.2 [95% CI 1.5–5.0] ng/mL; n = 33) compared with stroke patients without significant ICA stenosis (3.2 [95% CI 2.3–4.2] ng/mL; n = 72). Additionally, pial blood samples, reflecting intravascular molecular conditions during collateral flow, showed similar sGPVI levels when compared to the systemic ICA samples in both groups. Conclusions: Our findings indicate that GPVI is not locally cleaved and shed into the bloodstream in significant amounts during hyper-acute ischemic stroke, neither at the level of symptomatic ICA nor intracranially during collateral blood supply. Therefore, sGPVI does not appear to be suitable as a local stroke biomarker despite strong evidence of a major role for GPVI-signaling in stroke pathophysiology. [ABSTRACT FROM AUTHOR]

Aims: Cognitive impairment (CI) is a common, yet frequently unrecognized co‐morbidity in chronic heart failure (HF). We quantified trajectories of cognitive performance, brain volume, and related clinical outcome over a time course of 6 years. Methods and results: The Cognition.Matters‐HF cohort study recruited patients with stable HF of any aetiology and severity. Beyond cardiological assessment, the workup included cognitive testing and brain magnetic resonance imaging (MRI). Of 148 recruited patients, 70% exhibited CI at baseline. During the median follow‐up time of 69 months (quartiles: 68, 70), indicators of HF severity remained essentially unaltered. CI was also stable, with the exception of intensity of attention, where age‐adjusted t‐scores decreased from 42 (38, 46) to 38 (34, 44; P < 0.001). Complete sets of four serial brain MRI scans were available in 47 patients (32% of total sample). Total brain volume shrank by 0.4% per year, from 1103 (1060, 1143) cm3 to 1078 (1027, 1117) cm3, which was within limits observed in non‐diseased ageing individuals. During follow‐up, 29 study participants (20%) died, and 26 (18%) were at least once hospitalized due to worsening HF. The presence of CI was not associated with overall (P = 0.290) or hospitalization‐free (P = 0.450) survival. Conclusions: In patients with stable HF patients receiving guideline‐directed pharmacologic treatment and regular medical care, the presence of CI did not affect overall and hospitalization‐free 6‐year survival. The loss of brain parenchyma observed in patients with stable HF did not exceed that of normal ageing. [ABSTRACT FROM AUTHOR]

S100 calcium-binding protein B (S100B) is a protein primarily known as a biomarker for central nervous system (CNS) injuries, reflecting blood–brain barrier (BBB) permeability and dysfunction. Recently, S100B has also been implicated in cardiovascular diseases, including heart failure (HF). Thus, we investigated serum levels of S100B in 146 chronic HF patients from the Cognition.Matters-HF study and their association with cardiac and cognitive dysfunction. The median S100B level was 33 pg/mL (IQR: 22–47 pg/mL). Higher S100B levels were linked to longer HF duration (p = 0.014) and increased left atrial volume index (p = 0.041), but also with a higher prevalence of mild cognitive impairment (p = 0.023) and lower visual/verbal memory scores (p = 0.006). In a multivariable model, NT-proBNP levels independently predicted S100B (T-value = 2.27, p = 0.026). S100B did not impact mortality (univariable HR (95% CI) 1.00 (0.99–1.01); p = 0.517; multivariable HR (95% CI) 1.01 (1.00–1.03); p = 0.142), likely due to its reflection of acute injury rather than long-term outcomes and the mild HF phenotype in our cohort. These findings underscore S100B's value in comprehensive disease assessment, reflecting both cardiac dysfunction and potentially related BBB disruption. [ABSTRACT FROM AUTHOR]

Store-operated [Ca.sup.2+] entry (SOCE) is the major route of [Ca.sup.2+] influx in platelets. The [Ca.sup.2+] sensor stromal interaction molecule 1 (STIM1) triggers SOCE by forming punctate structures with the [Ca.sup.2+] channel Orai1 and the inositol trisphosphate receptor ([IP.sub.3]R), thereby linking the endo-/sarcoplasmic reticulum to the plasma membrane. Here, we identified the BAR domain superfamily member bridging integrator 2 (BIN2) as an interaction partner of STIM1 and [IP.sub.3]R in platelets. Deletion of platelet BIN2 ([Bin2.sup.fl/fl,Pf4,Cre] mice) resulted in reduced [Ca.sup.2+] store release and [Ca.sup.2+] influx in response to all tested platelet agonists. These defects were a consequence of impaired [IP.sub.3]R function in combination with defective STIM1-mediated SOC channel activation, while [Ca.sup.2+] store content and agonist-induced [IP.sub.3] production were unaltered. This severely defective [Ca.sup.2+] signaling translated into impaired thrombus formation under flow and a protection of [Bin2.sup.fl/fl,Pf4,Cre] mice in models of arterial thrombosis and stroke. Our results establish BIN2 as a central regulator of platelet activation in thrombosis and thrombo- inflammatory disease settings., Introduction Platelet activation and aggregation at the injured vessel wall is essential for primary hemostasis, but may also trigger occlusion of diseased vessels, resulting in acute ischemia and infarction of [...]