The NLRP3 Inflammasome Inhibitor, OLT1177 (Dapansutrile), Reduces Infarct Size and Preserves Contractile Function After Ischemia Reperfusion Injury in the Mouse.

BACKGROUND: Activation of the NLRP3 inflammasome is a primary driver of sterile inflammation in response to myocardial ischemia reperfusion. Pharmacologic inhibitors of the NLRP3 inflammasome are being developed. We proposed that OLT1177 (dapansutrile), a novel NLRP3 inflammasome inhibitor, could preserve myocardial function after ischemia reperfusion injury in the mouse. METHODS: We used an experimental murine model of myocardial ischemia reperfusion injury through transient ligation of the left coronary artery and measured the effects of OLT1177 (6, 60, or 600 mg/kg intraperitoneal dose) on infarct size at pathology and on systolic cardiac function at echocardiography. To simulate a clinical scenario, we investigated the time window of therapeutic intervention with OLT1177 (60 mg/kg) administered 60, 120, or 180 minutes after reperfusion. RESULTS: OLT1177 was rapidly detectable in the plasma following intraperitoneal injection and had no effect on cardiac function in healthy mice. OLT1177 treatment at reperfusion showed significant dose-dependent reduction in infarct size (-36%, -67%, and -62% for 6, 60, and 600 mg/kg, respectively; P < 0.001 for linear trend, P = 0.010 vs. vehicle for 6 mg/kg, and P < 0.001 vs. vehicle for 60 and 600 mg/kg) and preserved cardiac systolic function measured as left ventricular fractional shortening at 24 hours and 7 days after injury (P = 0.015 for 6 mg/kg and P < 0.01 for 60 and 600 mg/kg). OLT1177 reduced infarct size also when given after 60 minutes of reperfusion (-71%, P < 0.001 vs. vehicle). CONCLUSION: OLT1177 (dapansutrile) limits infarct size and prevents left ventricular systolic dysfunction when given within 60 minutes following ischemia reperfusion injury in the mouse.

An Orally Available NLRP3 Inflammasome Inhibitor Prevents Western Diet-Induced Cardiac Dysfunction in Mice.

BACKGROUND: A diet rich in saturated fat and sugars (Western diet, WD) induces myocardial expression of the NLRP3 inflammasome and dysfunction in mice. We therefore hypothesized that a diet enriched with an orally available NLRP3 inflammasome inhibitor could prevent WD-induced cardiac dysfunction in mice. METHODS: Ten-week-old CD-1 male mice were fed WD or standard diet (SD) for 8 weeks. The compound 16673-34-0, an orally active NLRP3 inhibitor, was added to the diet at a concentration of 100 mg/Kg. The plasmatic levels of the NLRP3 inflammasome inhibitor were measured. Food intake, body weight, and glucose tolerance were assessed. Cardiac systolic and diastolic functions were measured by Doppler echocardiography at baseline, 4 weeks, and 8 weeks. RESULTS: WD induced a significant increase in body weight (+14%, P = 0.02), impaired glucose tolerance (+34%, P = 0.03), and a significant increase in isovolumetric relaxation time (+129%, P = 0.03) and reduction in left ventricular ejection fraction (-10%, P = 0.03), as compared to standard chow diet (SD). The treatment with NLRP3 inhibitor in the diet prevented cardiac systolic and diastolic dysfunction (P < 0.05 for left ventricular ejection fraction, isovolumetric relaxation time, and myocardial performance index in WD with drug vs. WD without drug), without significant changes in heart rate and metabolic parameters. CONCLUSIONS: An orally available NLRP3 inhibitor prevented WD-induced cardiac dysfunction in obese mice.

A Preclinical Translational Study of the Cardioprotective Effects of Plasma-Derived Alpha-1 Anti-trypsin in Acute Myocardial Infarction.

BACKGROUND: The area of myocardial infarction continues to expand for hours after reperfusion. The injured but viable myocardium may be salvaged if the signals leading to cell death are interrupted. Activation of the caspase-1 inflammasome in the heart shortly after ischemia-reperfusion contributes to the final infarct size. Plasma-derived α-1 anti-trypsin (AAT) has shown to inhibit inflammasome formation in vitro and in vivo. To explore the potential translational clinical value of AAT as a therapeutic, we conducted a series of preclinical experiments designed to simulate clinically relevant scenarios. METHODS: Adult male CD1 mice were used. The left anterior descending coronary artery was ligated for 30 or 75 minutes followed by reperfusion, to explore different severity of ischemic injury. Plasma-derived AAT (Prolastin C) was administered intraperitoneally after reperfusion, without pretreatment, exploring 3 different doses (60, 120, and 180 mg/kg). In a subgroup of mice, we administered Prolastin C with a delay of 30 minutes after reperfusion to simulate the clinical context of delayed administration, and we also used a model of permanent coronary artery ligation without reperfusion. Finally, we tested whether a single dose at reperfusion was sufficient to maintain a benefit in the longer term (7 days). Infarct size was measured by 3 different and independent methodologies: pathology, plasma levels of troponin I, and wall motion abnormalities at echocardiography. RESULTS: Prolastin C given at reperfusion after 30 minutes of ischemia provided a powerful reduction in infarct size (>50% reduction in all methodology used, all P < 0.01) without a clear dose-dependent response. Prolongation of ischemia to 75 minutes nor a delay in treatment by 30 minutes after reperfusion had any negative impact on Prolastin C effects. A single dose given at reperfusion was as effective as multiple daily doses. When given to the mouse without reperfusion, Prolastin C failed to reduce infarct size. CONCLUSIONS: Plasma-derived AAT (Prolastin C) given as an adjunct to reperfusion powerfully limits the final infarct size across a wide range of experiments in the mouse reproducing clinically relevant scenarios, such as variable duration of ischemia, delay in administration in the drug, and a large therapeutic index.