Iodide Improves Outcome After Acute Myocardial Infarction in Rats and Pigs.

OBJECTIVES: In this study, we tested whether iodide would reduce heart damage in rat and pig models of acute myocardial infarction as a risk analysis for a human trial. DESIGN: Prospective blinded and randomized laboratory animal investigation. SETTING: Animal research laboratories. SUBJECTS: Sexually mature rats and pigs. INTERVENTIONS: Acute myocardial infarction was induced by temporary ligation of the coronary artery followed by reperfusion. Iodide was administered orally in rats or IV in rats and pigs just prior to reperfusion. MEASUREMENTS AND MAIN RESULTS: Damage was assessed by blood cardiac troponin and infarct size; heart function was determined by echocardiography. Blood peroxide scavenging activity was measured enzymatically, and blood thyroid hormone was determined using radioimmune assay. Iodide administration preserved heart function and reduced blood cardiac troponin and infarct size by approximately 45% in pigs and approximately 60% in rats. Iodide administration also increased blood peroxide scavenging activity and maintained thyroid hormone levels. CONCLUSIONS: Iodide administration improved the structure and function of the heart after acute myocardial infarction in rats and pigs.

A Randomized, double-blind, dose ranging clinical trial of intravenous FDY-5301 in acute STEMI patients undergoing primary PCI.

BACKGROUND: Ischemia-reperfusion injury remains a major clinical problem in patients with ST-elevation myocardial infarction (STEMI), leading to myocardial damage despite early reperfusion by primary percutaneous coronary intervention (PPCI). There are no effective therapies to limit ischemia-reperfusion injury, which is caused by multiple pathways activated by rapid tissue reoxygenation and the generation of reactive oxygen species (ROS). FDY-5301 contains sodium iodide, a ubiquitous inorganic halide and elemental reducing agent that can act as a catalytic anti-peroxidant. We tested the feasibility, safety and potential utility of FDY-5301 as a treatment to limit ischemia-reperfusion injury, in patients with first-time STEMI undergoing emergency PPCI. METHODS: STEMI patients (n = 120, median 62 years) presenting within 12 h of chest pain onset were randomized at 20 PPCI centers, in a double blind Phase 2 clinical trial, to receive FDY-5301 (0.5, 1.0 or 2.0 mg/kg) or placebo prior to reperfusion, to evaluate the feasibility endpoints. Participants underwent continuous ECG monitoring for 14 days after PPCI to address pre-specified cardiac arrhythmia safety end points and cardiac magnetic resonance imaging (MRI) at 72 h and at 3 months to assess exploratory efficacy end points. RESULTS: Intravenous FDY-5301 was delivered before re-opening of the infarct-related artery in 97% participants and increased plasma iodide levels ~1000-fold within 2 min. There was no significant increase in the primary safety end point of incidence of cardiac arrhythmias of concern. MRI at 3 months revealed median final infarct sizes in placebo vs. 2.0 mg/kg FDY-5301-treated patients of 14.9% vs. 8.5%, and LV ejection fractions of 53.9% vs. 63.2%, respectively, although the study was not powered to detect statistical significance. In patients receiving FDY-5301, there was a significant reduction in the levels of MPO, MMP2 and NTproBNP after PPCI, but no reduction with placebo. CONCLUSIONS: Intravenous FDY-5301, delivered immediately prior to PPCI in acute STEMI, is feasible, safe, and shows potential efficacy. A larger trial is justified to test the effects of FDY-5301 on acute ischemia-reperfusion injury and clinical outcomes. CLINICAL TRIAL REGISTRATION: CT.govNCT03470441; EudraCT 2017-000047-41.

Detection of exhaled hydrogen sulphide gas in healthy human volunteers during intravenous administration of sodium sulphide.

INTRODUCTION: Hydrogen sulphide (H(2)S) is an endogenous gaseous signaling molecule and potential therapeutic agent. Emerging studies indicate its therapeutic potential in a variety of cardiovascular diseases and in critical illness. Augmentation of endogenous sulphide concentrations by intravenous administration of sodium sulphide can be used for the delivery of H(2)S to the tissues. In the current study, we have measured H(2)S concentrations in the exhaled breath of healthy human volunteers subjected to increasing doses sodium sulphide in a human phase I safety and tolerability study. METHODS: We have measured reactive sulphide in the blood via ex vivo derivatization of sulphide with monobromobimane to form sulphide-dibimane and blood concentrations of thiosulfate (major oxidative metabolite of sulphide) via ion chromatography. We have measured exhaled H(2)S concentrations using a custom-made device based on a sulphide gas detector (Interscan). RESULTS: Administration of IK-1001, a parenteral formulation of Na(2)S (0.005-0.20 mg kg(-1), i.v., infused over 1 min) induced an elevation of blood sulphide and thiosulfate concentrations over baseline, which was observed within the first 1-5 min following administration of IK-1001 at 0.10 mg kg(-1) dose and higher. In all subjects, basal exhaled H(2)S was observed to be higher than the ambient concentration of H(2)S gas in room air, indicative of on-going endogenous H(2)S production in human subjects. Upon intravenous administration of Na(2)S, a rapid elevation of exhaled H(2)S concentrations was observed. The amount of exhaled H(2)S rapidly decreased after discontinuation of the infusion of Na(2)S. CONCLUSION: Exhaled H(2)S represents a detectable route of elimination after parenteral administration of Na(2)S.

Iodine Redistribution During Trauma, Sepsis, and Hibernation: An Evolutionarily Conserved Response to Severe Stress.

OBJECTIVE: We performed these studies to learn how iodine in the form of free iodide behaves during stress. DESIGN: Prospective observational trial using samples obtained from human trauma patients and retrospective observational study using remnant samples from human sepsis patients and arctic ground squirrels. Preclinical interventional study using hind-limb ischemia and reperfusion injury in mice. SETTING: Level I trauma center emergency room and ICU and animal research laboratories. SUBJECTS: Adult human sepsis and trauma patients, wild-caught adult arctic ground squirrels, and sexually mature laboratory mice. INTERVENTIONS: Ischemia and reperfusion injury was induced in mice by temporary application of tourniquet to one hind-limb. Iodide was administered IV just prior to reperfusion. MEASUREMENTS AND MAIN RESULTS: Free iodide was measured using ion chromatography. Relative to iodide in plasma from normal donors, iodide was increased 17-fold in plasma from trauma patients and 26-fold in plasma from sepsis patients. In arctic ground squirrels, iodide increases over three-fold during hibernation. And during ischemia/reperfusion injury in mice, iodide accumulates in ischemic tissue and reduces both local and systemic tissue damage. CONCLUSIONS: Iodide redistributes during stress and improves outcome after injury. Essential functions of iodide may have contributed to its evolutionary selection and be useful as a therapeutic intervention for human patients.

A small molecule-kinase interaction map for clinical kinase inhibitors.

Kinase inhibitors show great promise as a new class of therapeutics. Here we describe an efficient way to determine kinase inhibitor specificity by measuring binding of small molecules to the ATP site of kinases. We have profiled 20 kinase inhibitors, including 16 that are approved drugs or in clinical development, against a panel of 119 protein kinases. We find that specificity varies widely and is not strongly correlated with chemical structure or the identity of the intended target. Many novel interactions were identified, including tight binding of the p38 inhibitor BIRB-796 to an imatinib-resistant variant of the ABL kinase, and binding of imatinib to the SRC-family kinase LCK. We also show that mutations in the epidermal growth factor receptor (EGFR) found in gefitinib-responsive patients do not affect the binding affinity of gefitinib or erlotinib. Our results represent a systematic small molecule-protein interaction map for clinical compounds across a large number of related proteins.

A monobromobimane-based assay to measure the pharmacokinetic profile of reactive sulphide species in blood.

BACKGROUND AND PURPOSE: Hydrogen sulphide (H(2)S) is a labile, endogenous metabolite of cysteine, with multiple biological roles. The development of sulphide-based therapies for human diseases will benefit from a reliable method of quantifying H(2)S in blood and tissues. EXPERIMENTAL APPROACH: Concentrations of reactive sulphide in saline and freshly drawn whole blood were quantified by reaction with the thio-specific derivatization agent monobromobimane, followed by reversed-phase fluorescence HPLC and/or mass spectrometry. In pharmacokinetic studies, male rats were exposed either to intravenous infusions of sodium sulphide or to H(2)S gas inhalation, and levels of available blood sulphide were measured. Levels of dissolved H(2)S/HS(-) were concomitantly measured using an amperometric sensor. KEY RESULTS: Monobromobimane was found to rapidly and quantitatively derivatize sulphide in saline or whole blood to yield the stable small molecule sulphide dibimane. Extraction and quantification of this bis-bimane derivative were validated via reversed-phase HPLC separation coupled to fluorescence detection, and also by mass spectrometry. Baseline levels of sulphide in blood were in the range of 0.4-0.9 microM. Intravenous administration of sodium sulphide solution (2-20 mg x kg(-1) x h(-1)) or inhalation of H(2)S gas (50-400 ppm) elevated reactive sulphide in blood in a dose-dependent manner. Each 1 mg x kg(-1) x h(-1) of sodium sulphide infusion into rats was found to be pharmacokinetically equivalent to approximately 30 ppm of H(2)S gas inhalation. CONCLUSIONS AND IMPLICATIONS: The monobromobimane derivatization method is a sensitive and reliable means to measure reactive sulphide species in whole blood. Using this method, we have established a bioequivalence between infused sodium sulphide and inhaled H(2)S gas.

Detection of exhaled hydrogen sulphide gas in rats exposed to intravenous sodium sulphide.

BACKGROUND AND PURPOSE: Sodium sulphide (Na(2)S) disassociates to sodium (Na(+)) hydrosulphide, anion (HS(-)) and hydrogen sulphide (H(2)S) in aqueous solutions. Here we have established and characterized a method to detect H(2)S gas in the exhaled breath of rats. EXPERIMENTAL APPROACH: Male rats were anaesthetized with ketamine and xylazine, instrumented with intravenous (i.v.) jugular vein catheters, and a tube inserted into the trachea was connected to a pneumotach connected to a H(2)S gas detector. Sodium sulphide, cysteine or the natural polysulphide compound diallyl disulphide were infused intravenously while the airway was monitored for exhaled H(2)S real time. KEY RESULTS: Exhaled sulphide concentration was calculated to be in the range of 0.4-11 ppm in response to i.v. infusion rates ranging between 0.3 and 1.1 mg x kg(-1) x min(-1). When nitric oxide synthesis was inhibited with N(omega)-nitro-L-arginine methyl ester the amount of H(2)S exhaled during i.v. infusions of sodium sulphide was significantly increased compared with that obtained with the vehicle control. An increase in circulating nitric oxide using DETA NONOate [3,3-bis(aminoethyl)-1-hydroxy-2-oxo-1-triazene] did not alter the levels of exhaled H(2)S during an i.v. infusion of sodium sulphide. An i.v. bolus of L-cysteine, 1 g.kg(-1), and an i.v. infusion of the garlic derived natural compound diallyl disulphide, 1.8 mg x kg(-1) x min(-1), also caused exhalation of H(2)S gas. CONCLUSIONS AND IMPLICATIONS: This method has shown that significant amounts of H(2)S are exhaled in rats during sodium sulphide infusions, and the amount exhaled can be modulated by various pharmacological interventions.