PAR4 (Protease-Activated Receptor 4) Antagonism with BMS-986120 Inhibits Human Ex Vivo Thrombus Formation

Objective-BMS-986120 is a novel first-in-class oral PAR4 (protease-Activated receptor 4) antagonist with potent and selective antiplatelet effects. We sought to determine for the first time, the effect of BMS-986120 on human ex vivo thrombus formation. Approach and Results-Forty healthy volunteers completed a phase 1 parallel-group PROBE trial (Prospective Randomized Open-Label Blinded End Point). Ex vivo platelet activation, platelet aggregation, and thrombus formation were measured at 0, 2, and 24 hours after (1) oral BMS-986120 (60 mg) or (2) oral aspirin (600 mg) followed at 18 hours with oral aspirin (600 mg) and oral clopidogrel (600 mg). BMS-986120 demonstrated highly selective and reversible inhibition of PAR4 agonist peptide (100 μM)-stimulated P-selectin expression, platelet-monocyte aggregates, and platelet aggregation (P<0.001 for all). Compared with pretreatment, total thrombus area (μm2/mm) at high shear was reduced by 29.2% (95% confidence interval, 18.3%-38.7%; P<0.001) at 2 hours and by 21.4% (9.3%-32.0%; P=0.002) at 24 hours. Reductions in thrombus formation were driven by a decrease in platelet-rich thrombus deposition: 34.8% (19.3%-47.3%; P<0.001) at 2 hours and 23.3% (5.1%-38.0%; P=0.016) at 24 hours. In contrast to aspirin alone, or in combination with clopidogrel, BMS-986120 had no effect on thrombus formation at low shear (P=nonsignificant). BMS-986120 administration was not associated with an increase in coagulation times or serious adverse events. Conclusions-BMS-986120 is a highly selective and reversible oral PAR4 antagonist that substantially reduces platelet-rich thrombus formation under conditions of high shear stress. Our results suggest PAR4 antagonism has major potential as a therapeutic antiplatelet strategy. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT02439190

Activation of a novel natriuretic endocrine system in humans with heart failure

Proguanylin and prouroguanylin are the inactive precursors of guanylin and uroguanylin, natriuretic peptides involved in the regulation of sodium balance. Urinary uroguanylin levels have been found previously to be elevated in patients with HF (heart failure). The aim of the present study was to investigate whether plasma proguanylin and prouroguanylin levels are increased in patients with HF and to evaluate their relationship with cardiac and renal function. In this prospective observational study, we recruited 243 patients with HF (151 men) and 72 healthy controls. In patients with HF, plasma levels of proguanylin [median, 7.2 (range, 0.9–79.0) μg/l] and prouroguanylin [8.3 (1.7–53.0 μg/l)] were both significantly (P<0.0005) higher compared with levels in healthy controls [5.5 (0.4–22.3 μg/l) for proguanylin and 6.3 (2.5–16.9) μg/l for prouroguanylin]. In patients with HF, increased age, a history of hypertension, diabetes and atrial fibrillation, use of diuretics, a higher NYHA (New York Heart Association) class and a lower eGFR (estimated glomerular filtration rate) were significant univariate predictors of proguanylin and prouroguanylin levels. In multivariate analysis, a history of hypertension and low eGFR both had strong independent associations with proguanylin and prouroguanylin levels. Proguanylin and prouroguanylin varied significantly between NYHA class with a trend of increasing plasma concentrations with worsening severity of symptoms. In conclusion, plasma proguanylin and prouroguanylin are elevated in patients with HF. Elevated plasma proguanylin and prouroguanylin levels are associated with hypertension, renal impairment and increasing severity of HF. This novel endocrine system may contribute to the pathophysiology of HF

Using matrix assisted laser desorption ionisation mass spectrometry (MALDI-MS) profiling in order to predict clinical outcomes of patients with heart failure

Background Current risk prediction models in heart failure (HF) including clinical characteristics and biomarkers only have moderate predictive value. The aim of this study was to use matrix assisted laser desorption ionisation mass spectrometry (MALDI-MS) profiling to determine if a combination of peptides identified with MALDI-MS will better predict clinical outcomes of patients with HF. Methods A cohort of 100 patients with HF were recruited in the biomarker discovery phase (50 patients who died or had a HF hospital admission vs. 50 patients who did not have an event). The peptide extraction from plasma samples was performed using reversed phase C18. Then samples were analysed using MALDI-MS. A multiple peptide biomarker model was discovered that was able to predict clinical outcomes for patients with HF. Finally, this model was validated in an independent cohort with 100 patients with HF. Results After normalisation and alignment of all the processed spectra, a total of 11,389 peptides (m/z) were detected using MALDI-MS. A multiple biomarker model was developed from 14 plasma peptides that was able to predict clinical outcomes in HF patients with an area under the receiver operating characteristic curve (AUC) of 1.000 (p = 0.0005). This model was validated in an independent cohort with 100 HF patients that yielded an AUC of 0.817 (p = 0.0005) in the biomarker validation phase. Addition of this model to the BIOSTAT risk prediction model increased the predictive probability for clinical outcomes of HF from an AUC value of 0.643 to an AUC of 0.823 (p = 0.0021). Moreover, using the prediction model of fourteen peptides and the composite model of the multiple biomarker of fourteen peptides with the BIOSTAT risk prediction model achieved a better predictive probability of time-to-event in prediction of clinical events in patients with HF (p = 0.0005). Conclusions The results obtained in this study suggest that a cluster of plasma peptides using MALDI-MS can reliably predict clinical outcomes in HF that may help enable precision medicine in HF

Guanylin peptides in heart failure

This study investigated the role of prouroguanylin (ProUGN) and proguanylin (ProGN), members of a novel class of peptides with natriuretic activity in heart failure (HF), a disorder of declining cardiac output associated with disturbed sodium and water homeostasis. The hypothesis was that ProUGN and ProGN activity is dysregulated in chronic and acute HF. Plasma ProUGN and ProGN were measured in 243 patients with chronic stable HF and plasma ProUGN and cGMP, an intracellular mediator of ProUGN activity, measured in 336 patients admitted to hospital with acute HF using immunoassays. ProUGN and cGMP levels were repeated in acute HF patients prior to discharge. The primary endpoints were all cause mortality, HF readmission and either outcome at 180 days. ProUGN and ProGN were significantly greater in patients with chronic HF compared to controls and inversely correlated with eGFR. ProUGN and ProGN were significantly greater in patients with hypertension and in those taking diuretics, with higher levels associated with increased severity of HF as assessed by NYHA class. In multivariate analysis, eGFR was the only independent predictor of plasma ProUGN and ProGN level. ProUGN and cGMP were significantly lower in patients with acute HF compared to in controls. Pre-discharge ProUGN and cGMP were significantly greater than at admission, with pre-discharge ProUGN significantly greater than in controls. Admission ProUGN was significantly greater in patients who died and a greater pre-discharge ProUGN was significantly associated with increased risk of early mortality. Pre-discharge cGMP levels were significantly lower in those readmitted with HF compared to those not, with higher levels significantly associated with reduced risk of early HF readmission. A greater pre-discharge ProUGN/cGMP ratio was significantly associated with increased risk of mortality or HF readmission. These results suggest that adverse outcomes in HF may be associated with hyporesponsiveness to ProUGN

Guanylin peptides in heart failure

This study investigated the role of prouroguanylin (ProUGN) and proguanylin (ProGN), members of a novel class of peptides with natriuretic activity in heart failure (HF), a disorder of declining cardiac output associated with disturbed sodium and water homeostasis. The hypothesis was that ProUGN and ProGN activity is dysregulated in chronic and acute HF. Plasma ProUGN and ProGN were measured in 243 patients with chronic stable HF and plasma ProUGN and cGMP, an intracellular mediator of ProUGN activity, measured in 336 patients admitted to hospital with acute HF using immunoassays. ProUGN and cGMP levels were repeated in acute HF patients prior to discharge. The primary endpoints were all cause mortality, HF readmission and either outcome at 180 days. ProUGN and ProGN were significantly greater in patients with chronic HF compared to controls and inversely correlated with eGFR. ProUGN and ProGN were significantly greater in patients with hypertension and in those taking diuretics, with higher levels associated with increased severity of HF as assessed by NYHA class. In multivariate analysis, eGFR was the only independent predictor of plasma ProUGN and ProGN level. ProUGN and cGMP were significantly lower in patients with acute HF compared to in controls. Pre-discharge ProUGN and cGMP were significantly greater than at admission, with pre-discharge ProUGN significantly greater than in controls. Admission ProUGN was significantly greater in patients who died and a greater pre-discharge ProUGN was significantly associated with increased risk of early mortality. Pre-discharge cGMP levels were significantly lower in those readmitted with HF compared to those not, with higher levels significantly associated with reduced risk of early HF readmission. A greater pre-discharge ProUGN/cGMP ratio was significantly associated with increased risk of mortality or HF readmission. These results suggest that adverse outcomes in HF may be associated with hyporesponsiveness to ProUGN.EThOS - Electronic Theses Online ServiceBritish Heart Foundation (FS/09/040)GBUnited Kingdo

Proteinase 3 and prognosis of patients with acute myocardial infarction.

A multimarker approach may be useful for risk stratification in AMI (acute myocardial infarction) patients, particularly utilizing pathways that are pathophysiologically distinct. Our aim was to assess the prognostic value of PR3 (proteinase 3) in patients post-AMI. We compared the prognostic value of PR3, an inflammatory marker, with an established marker NT-proBNP (N-terminal pro-B-type natriuretic peptide) post-AMI. We recruited 900 consecutive post-AMI patients (700 men; age, 64.6±12.4 years) in a prospective study with follow-up over 347 (0-764) days. Plasma PR3 was significantly higher in patients who died [666.2 (226.8-4035.5) ng/ml; P<0.001] or were readmitted with heart failure [598 (231.6-1803.9) ng/ml, P<0.004] compared with event-free survivors [486.9 (29.3-3118.2) ng/ml]. Using Cox modelling, log10 PR3 [HR (hazard ratio), 3.80] and log10 NT-proBNP (HR, 2.51) were significant independent predictors of death or heart failure. When patients were stratified by plasma NT-proBNP (median, 1023 pmol/l), PR3 gave additional predictive value for death or heart failure, in both the patients in whom NT-proBNP level was above the median (log rank for trend, 12.54; P<0.0004) and those with NT-proBNP level below the median (log rank for trend, 3.83; P<0.05). Neither marker predicted recurrent AMI. In conclusion, this is the first report showing a potential role for the serine protease PR3 in determining mortality and incidence of heart failure following AMI, independent of established conventional risk factors. PR3 may represent a clinically useful marker of prognosis after an AMI as part of a multimarker strategy