The 10th Biennial Hatter Cardiovascular Institute workshop: cellular protection-evaluating new directions in the setting of myocardial infarction, ischaemic stroke, and cardio-oncology.

Due to its poor capacity for regeneration, the heart is particularly sensitive to the loss of contractile cardiomyocytes. The onslaught of damage caused by ischaemia and reperfusion, occurring during an acute myocardial infarction and the subsequent reperfusion therapy, can wipe out upwards of a billion cardiomyocytes. A similar program of cell death can cause the irreversible loss of neurons in ischaemic stroke. Similar pathways of lethal cell injury can contribute to other pathologies such as left ventricular dysfunction and heart failure caused by cancer therapy. Consequently, strategies designed to protect the heart from lethal cell injury have the potential to be applicable across all three pathologies. The investigators meeting at the 10th Hatter Cardiovascular Institute workshop examined the parallels between ST-segment elevation myocardial infarction (STEMI), ischaemic stroke, and other pathologies that cause the loss of cardiomyocytes including cancer therapeutic cardiotoxicity. They examined the prospects for protection by remote ischaemic conditioning (RIC) in each scenario, and evaluated impasses and novel opportunities for cellular protection, with the future landscape for RIC in the clinical setting to be determined by the outcome of the large ERIC-PPCI/CONDI2 study. It was agreed that the way forward must include measures to improve experimental methodologies, such that they better reflect the clinical scenario and to judiciously select combinations of therapies targeting specific pathways of cellular death and injury.

Cangrelor-Mediated Cardioprotection Requires Platelets and Sphingosine Phosphorylation.

In animal models platelet P2Y12 receptor antagonists put the heart into a protected state, not as a result of suppressed thrombosis but rather through protective signaling, similar to that for ischemic postconditioning. While both ischemic postconditioning and the P2Y12 blocker cangrelor protect blood-perfused hearts, only the former protects buffer-perfused hearts indicating that the blocker requires a blood-borne constituent or factor to protect. We used an anti-platelet antibody to make thrombocytopenic rats to test if that factor resides within the platelet. Infarct size was measured in open-chest rats subjected to 30-min ischemia/2-h reperfusion. Infarct size was not different in thrombocytopenic rats showing that preventing aggregation alone is not protective. While ischemic preconditioning could reduce infarct size in thrombocytopenic rats, the P2Y12 inhibitor cangrelor could not, indicating that it protects by interacting with some factor in the platelet. Ischemic preconditioning is known to require phosphorylation of sphingosine. In rats treated with dimethylsphingosine to block sphingosine kinase, cangrelor was no longer protective. Thus cangrelor's protective mechanism appears to also involve sphingosine kinase revealing yet another similarity to conditioning's mechanism.

Matrix metalloproteinase inhibition protects CyPD knockout mice independently of RISK/mPTP signalling: a parallel pathway to protection.

The mitochondrial permeability transition pore (mPTP) is widely accepted as an end-effector mechanism of conditioning protection against injurious ischaemia/reperfusion. However, death can be initiated in cells without pre-requisite mPTP opening, implicating alternate targets for ischaemia/reperfusion injury amelioration. Matrix metalloproteinases (MMP) are known to activate extrinsic apoptotic cascades and therefore we hypothesised that MMP activity represents an mPTP-independent target for augmented attenuation of ischaemia/reperfusion injury. In ex vivo and in vivo mouse hearts, we investigated whether the MMP inhibitor, ilomastat (0.25 µmol/l), administered upon reperfusion could engender protection in the absence of cyclophilin-D (CyPD), a modulator of mPTP opening, against injurious ischaemia/reperfusion. Ilomastat attenuated infarct size in wild-type (WT) animals [37 ± 2.8 to 22 ± 4.3 %, equivalent to ischaemic postconditioning (iPostC), used as positive control, 27 ± 2.1 %, p < 0.05]. Control CyPD knockout (KO) hearts had smaller infarcts than control WT (28 ± 4.2 %) and iPostC failed to confer additional protection, yet ilomastat significantly attenuated infarct size in KO hearts (11 ± 3.0 %, p < 0.001), and similar protection was also seen in isolated cardiomyocytes. Moreover, ilomastat, unlike the cyclophilin inhibitor cyclosporine-A, had no impact upon reactive oxygen species-mediated mPTP opening. While MMP inhibition was associated with increased Akt and ERK phosphorylation, neither Wortmannin nor PD98059 abrogated ilomastat-mediated protection. We demonstrate that MMP inhibition is cardioprotective, independent of Akt/ERK/CyPD/mPTP activity and is additive to the protection observed following inhibition of mPTP opening, indicative of a parallel pathway to protection in ischaemic/reperfused heart that may have clinical applicability in attenuating injury in acute coronary syndromes and deserve further investigation.

Conditioning the whole heart--not just the cardiomyocyte.

Conditioning, the recruitment of endogenous cytoprotective pathways that protect the myocardium against injurious ischaemia/reperfusion injury, has developed into a range of modalities that can be applied before (preconditioning), during (perconditioning) or after the injurious ischaemic insult (postconditioning), either directly to the heart or in a distal tissue (remote preconditioning). A wide range of triggers, signaling pathways and potential end-effector mechanisms have been identified, which appear common to all forms of conditioning. Interestingly, conditioning applies to not only the cardiac myocyte, but to all the constitutive cell types within the myocardium. As our understanding of conditioning mechanisms continue to develop and we start to realise some of the difficulties in translating these phenomena to clinical treatments, it may be time to take a more integrative approach to conditioning, considering the many cellular and tissue types within the heart, and how they contribute to cytoprotective adaptations. In this review, we shall look at the conditioning phenomena, how different cell types contribute to the conditioned phenotype, and where novel cardioprotective modalities may be developed.

Retrograde heart perfusion: the Langendorff technique of isolated heart perfusion.

In the late 19th century, a number of investigators were working on perfecting isolated heart model, but it was Oscar Langendorff who, in 1895, pioneered the isolated perfused mammalian heart. Since that time, the Langendorff preparation has evolved and provided a wealth of data underpinning our understanding of the fundamental physiology of the heart: its contractile function, coronary blood flow regulation and cardiac metabolism. In more recent times, the procedure has been used to probe pathophysiology of ischaemia/reperfusion and disease states, and with the dawn of molecular biology and genetic manipulation, the Langendorff perfused heart has remained a stalwart tool in the study of the impact upon the physiology of the heart by pharmacological inhibitors and targeted deletion or up-regulation of genes and their impact upon intracellular signalling and adaption to clinically relevant stressful stimuli. We present here the basic structure of the Langendorff system and the fundamental experimental rules which warrant a viable heart preparation. In addition, we discuss the use of the isolated retrograde perfused heart in the model of ischaemia-reperfusion injury ex-vivo, and its applicability to other areas of study. The Langendorff perfusion apparatus is highly adaptable and this is reflected not only in the procedure's longevity but also in the number of different applications to which it has been turned.

SGLT2 inhibitors reduce infarct size in reperfused ischemic heart and improve cardiac function during ischemic episodes in preclinical models.

The sodium-glucose cotransporter 2 (SGLT2) inhibitors are a new class of effective drugs managing patients, who suffer from type 2 diabetes (T2D): Landmark clinical trials including EMPA-REG, CANVAS and Declare-TIMI have demonstrated that SGLT2 inhibitors reduce cardiovascular mortality and re-hospitalization for heart failure (HF) in patients with T2D. It is well established that there is a strong independent relationship among infarct size measured within 1 month after reperfusion and all-cause death and hospitalization for HF: The fact that cardiovascular mortality was significantly reduced with the SGLT2 inhibitors, fuels the assumption that this class of therapies may attenuate myocardial infarct size. Experimental evidence demonstrates that SGLT2 inhibitors exert cardioprotective effects in animal models of acute myocardial infarction through improved function during the ischemic episode, reduction of infarct size and a subsequent attenuation of heart failure development. The aim of the present review is to outline the current state of preclinical research in terms of myocardial ischemia/reperfusion injury (I/R) and infarct size for clinically available SGLT2 inhibitors and summarize some of the proposed mechanisms of action (lowering intracellular Na+ and Ca2+, NHE inhibition, STAT3 and AMPK activation, CamKII inhibition, reduced inflammation and oxidative stress) that may contribute to the unexpected beneficial cardiovascular effects of this class of compounds.

SGLT2 Inhibitor, Canagliflozin, Attenuates Myocardial Infarction in the Diabetic and Nondiabetic Heart.

The authors hypothesized that despite similar cardiovascular event rates, the improved cardiovascular survival from sodium glucose transporter 2 (SGLT2) inhibition, seen clinically, could be via a direct cytoprotective effect, including protection against myocardial ischemia/reperfusion injury. Langendorff-perfused hearts, from diabetic and nondiabetic rats, fed long-term for 4 weeks with canagliflozin, had lower infarct sizes; this being the first demonstration of canagliflozin's cardioprotective effect against ischemia/reperfusion injury in both diabetic and nondiabetic animals. By contrast, direct treatment of isolated nondiabetic rat hearts with canagliflozin, solubilized in the isolated Langendorff perfusion buffer, had no impact on infarct size. This latter study demonstrates that the infarct-sparing effect of long-term treatment with canagliflozin results from either a glucose-independent effect or up-regulation of cardiac prosurvival pathways. These results further suggest that SGLT2 inhibitors could be repurposed as novel cardioprotective interventions in high-risk cardiovascular patients irrespective of diabetic status.

Reperfusion kinase phosphorylation is essential but not sufficient in the mediation of pharmacological preconditioning: Characterisation in the bi-phasic profile of early and late protection.

OBJECTIVE: Pharmacological preconditioning (PPC) triggers early (ePPC) and delayed protection (dPPC), occurring within 1 h or after 24 h following the preconditioning stimulus, respectively, through recruitment of protein kinase signalling. Angiotensin II (ATII) is a recognised trigger of PPC, recruiting kinases and transcription factors known to be involved in both phases of protection. Our objectives were to determine whether ATII is capable of triggering dPPC and whether recruitment of pro-survival kinases, Akt and extracellular signal-regulated kinase (ERK), following the injurious ischaemic insult is essential for the mediation of PPC. METHODS: In a mouse Langendorff model of ischaemia/reperfusion injury, we undertook to determine whether ATII triggers both ePPC and dPPC. Western blot analysis was used to determine kinase phosphorylation at reperfusion, and kinase inhibitors wortmannin and PD98059 were used to ascertain the significance of kinase regulation. RESULTS: We demonstrated that ATII triggered PPC with attenuation of infarction at 1 and 24 h (19+/-4% and 25+/-4% versus control, 35+/-4% of risk zone, p < 0.05), consistent with the ePPC and dPPC time-course. This bi-phasic protection was associated with significant post-ischaemic phosphorylation of both Akt and ERK within the first 5 min of reperfusion. Akt and ERK phosphorylation was increased following ePPC by 4.5+/-0.5 and 1.9+/-0.6 fold, respectively (p < 0.001), and dPPC by 24+/-2.0 and 2.1+/-0.1 fold, respectively (p < 0.001). Both wortmannin and PD98059 administered during reperfusion ameliorated the phosphorylation of Akt and ERK and abrogated the resistance to infarction resulting from both ePPC and dPPC (33+/-3% and 35+/-4%, respectively, versus controls 33+/-4% and 33+/-5%, p = NS). There was no evidence of augmented phosphorylation of either p38 kinase or JNK at either time point. CONCLUSION: We demonstrate that PPC results in a clearly delineated time-course of bi-phasic protection against injurious ischemic injury that is correlated with reperfusion kinase phosphorylation of both Akt and ERK. These data indicate a novel mechanism of early and particularly delayed preconditioning.

Pivotal role of NOX-2-containing NADPH oxidase in early ischemic preconditioning.

Reactive oxygen species (ROS)-mediated signaling is implicated in early ischemic preconditioning (PC). A NOX-2-containing NADPH oxidase is a recognized major source of ROS in cardiac myocytes, whose activity is augmented by preconditioning mimetics, such as angiotensin II. We hypothesized that this oxidase is an essential source of ROS in PC. Hearts from wild-type (WT) and NOX-2 knockout (KO) mice were Langendorff perfused and subjected to 35 min ischemia/reperfusion with or without preceding PC or drug treatment. Infarct size was measured by triphenyl tetrazolium chloride staining, and NADPH oxidase activity by lucigenin chemiluminescence. PC significantly attenuated infarct size in WT (26+/-2% vs. control, 38+/-2%, P<0.05) yet was ineffective in KO hearts (33+/-3% vs. control, 34+/-3%). Concomitantly, PC significantly increased NADPH oxidase activity in WT (+41+/-13%; P<0.05), but not in KO (-5+/-18%, P=NS). The ROS scavenger MPG (N-2-mercaptopropionyl glycine, 300 micromol/L) abrogated PC in WT (39+/-2% vs. control, 33+/-1%). CCPA (2-chloro N6 cyclopentyl adenosine, 200 nmol/L), a putative ROS-independent PC trigger, significantly attenuated infarct size in WT, MPG-treated WT and KO hearts (24+/-2, 23+/-1, and 20+/-3%, respectively, P<0.05). Furthermore, CCPA did not augment NADPH oxidase activity over control (+22+/-11%, P=NS). Inhibition of protein kinase C (PKC) with chelerythrine (CHE, 2 micromol/L) completely abrogated both PC (38+/-2% vs. CHE alone, 35+/-2%) and associated increases in oxidase activity (+3+/-10%, P=NS). PKC-dependent activation of a NOX-2-containing NADPH oxidase is pivotally involved in early ischemic PC. However, adenosine receptor activation can trigger a ROS and NOX-2 independent PC pathway.

Characterization of the Langendorff Perfused Isolated Mouse Heart Model of Global Ischemia-Reperfusion Injury: Impact of Ischemia and Reperfusion Length on Infarct Size and LDH Release.

INTRODUCTION: The Langendorff perfused isolated mouse heart model is commonly used to assess the efficacy of cardioprotective therapies, although the duration of ischemia and reperfusion vary considerably between different laboratories. We aimed to provide a thorough characterization of the model with different durations of ischemia and reperfusion by means of 2 different end points-infarct size (IS) using triphenyltetrazolium staining and lactate dehydrogenase (LDH) release. METHODS: C57/BL6 mice hearts were retrograde perfused on a Langendorff apparatus and allocated into 9 groups in a 3 × 3 factorial design-3 ischemic durations (25, 35, and 45 minutes) matched by 3 reperfusion durations (60, 120, and 180 minutes). A protocol of ischemic preconditioning (IPC) was applied to investigate IS and LDH kinetics with different ischemic durations. RESULTS: Infarct size progressively increased with the duration of both ischemia and reperfusion and was found to be independently associated with both determinants. In terms of LDH release kinetics, a peak was observed within the first 10 to 15 minutes of reperfusion and steadily declined thereafter, although a second smaller peak was observed in the 25-minute ischemia group. Only LDH peak release was associated with the ischemia length, with area under the curve (AUC) failing to follow ischemic duration. Interestingly, while IPC reduced IS in all ischemic durations investigated, a significant attenuation of LDH AUC was only observed in the 25-minute index ischemia group. Only a moderately positive correlation was observed between IS and LDH peak (R = .547, P = .006) and AUC (R = .664, P < .001). CONCLUSION: Myocardial IS measured by triphenyltetrazolium staining depends on both the duration of ischemia and the length of the reperfusion period. The LDH assessment may not be the most reliable tool to assess IS and/or to examine cardioprotective effectiveness at various times of ischemia.

Ischemic preconditioning: a potential role for protein S-thiolation?

Oxidant stress plays a crucial role in the triggering of cardioprotection involving ischemic preconditioning (IPC). We have used biotin-tagged cysteine to probe for redox-modified proteins in IPC protocols. Cysteine was biotinylated and introduced into isolated rat hearts. S-Thiolated proteins were detected and quantified using nonreducing western blots probed with streptavidin-horseradish peroxidase. Controls (15 min of aerobic perfusion plus 5 min of 0.5 mM biotin-cysteine plus 5 min of aerobic perfusion) showed low-level protein S-thiolation. Hearts preconditioned with 5 min of ischemia and reperfused for 5 min with biotin-cysteine plus 5 min of aerobic perfusion showed increased thiolation (160%) that was fully blocked by the antioxidant mercaptopropionylglycine, which is also known to block IPC. "Preconditioning" agonists (phorbol 12-myristate 13-acetate or phenylephrine) or oxidants (hydrogen peroxide or diamide) administered during aerobic preparations to biotin-cysteine-loaded hearts induced efficient protein S-thiolation. Preconditioning agonist-induced S-thiolation was significantly attenuated by diphenyleneiodonium (a flavoprotein inhibitor) or by the protein kinase C inhibitor bisindolylmaleimide I. Additional studies testing the role of a Nox2-containing NAD(P)H oxidase as the source of the oxidant stress essential to the triggering IPC showed that protein S-thiolation was the same in wild-type and Nox2 knockout mice.

Atorvastatin, administered at the onset of reperfusion, and independent of lipid lowering, protects the myocardium by up-regulating a pro-survival pathway.

OBJECTIVES: The purpose of this study was to determine whether atorvastatin, a 3-hydroxy-3-methylglutaryl (HMG)-co-enzyme A (CoA) reductase inhibitor, limits myocardial necrosis when administered as an adjunct to reperfusion. BACKGROUND: Statins inhibit HMG-CoA reductase to reduce the synthesis of cholesterol. However, it is proposed that statins have cardiovascular effects beyond their ability to lower cholesterol, possibly via recruitment of phosphatidyl inositol 3-kinase (PI3K) and the serine/threonine kinase, Akt. This signaling pathway has recently been linked to growth factor-mediated reperfusion salvage. METHODS: Isolated perfused mouse hearts were subjected to 35 min of global ischemia and reperfused for 30 min in the presence of incremental concentrations of atorvastatin. Infarct size was determined by triphenyltetrazolium chloride staining, and the activity of the PI3K signaling cascade was determined by Western blot analysis. RESULTS: We found that there was a profound dose-dependent reduction of infarct size with atorvastatin in the range of 25 to 100 micromol/l (optimal protection was seen at 50 micromol/l with infarct size of 16 +/- 2% vs. control, 33 +/- 2%, p < 0.01). Moreover, this protection was sensitive to inhibition with the PI3 kinase inhibitor, wortmannin, and was absent in endothelial nitric oxide synthase (eNOS) knockout mice. Western blot analysis revealed that atorvastatin resulted in rapid activation of the PI3K/Akt signaling cascade (within 5 min) and that both Akt and eNOS phosphorylation were significantly increased by 4.1-fold and 2.9-fold, respectively (p < 0.01). Moreover, phosphorylation of the PI3K substrates was abrogated by the administration of wortmannin. CONCLUSIONS: Atorvastatin attenuates lethal reperfusion-induced injury in a manner that is reliant on PI3K and Akt activity and the presence and activity of eNOS.

Hospital pharmacy and emergency department availability of parenteral pyridoxine.

OBJECTIVES: Pyridoxine is a recommended antidote that should be available in emergency departments (EDs). A pediatric use of this preparation is the treatment of acute seizures secondary to pyridoxine dependency or responsiveness. Two cases of children with pyridoxine-dependent and pyridoxine-responsive seizures whose treatment was affected by the unavailability of pyridoxine in local EDs are presented. These cases prompted the development of a survey to ascertain the availability of parenteral pyridoxine in the pharmacies and EDs of both children's and general hospitals in the United States. METHODS: A survey of 203 pharmacy directors in 100 pediatric hospitals (42 self-governing and 58 within a hospital) and 103 general hospitals was conducted. The questionnaire asked for the number of licensed beds and whether injectable pyridoxine was on the formulary and stocked by the ED. RESULTS: The overall response rate was 73% (83% pediatric and 64% general hospitals). Injectable pyridoxine was on the formulary of 99% of pediatric hospitals and 91% of general hospitals (P = 0.044). Of those hospitals that had pyridoxine on the formulary, the availability of injectable pyridoxine in EDs was low in both pediatric (20.7%) and general hospitals (16.7%). CONCLUSIONS: Given the number of possible uses of parenteral pyridoxine in the ED, it is suggested that there is a case for all pediatric and general hospital pharmacies to have it on the formulary and further for all EDs in these hospitals to have injectable pyridoxine available for immediate use.

The cardioprotective and mitochondrial depolarising properties of exogenous nitric oxide in mouse heart.

OBJECTIVE: Nitric oxide (NO) is reported to be both protective and detrimental in models of myocardial ischaemia/reperfusion injury, which may be concentration dependent. Our objective was to characterise this dichotomy using the nitric oxide donor, S-nitroso N-acetyl penicillamine (SNAP) in isolated perfused mouse heart and isolated mouse cardiac mitochondria. METHODS: To determine the effect of nitric oxide concentration on myocardial viability, isolated mouse hearts were subjected to 35 min global ischaemia and 30 min reperfusion in the presence of SNAP (0.02-20 microM). To determine whether NO mediated protection was via opening of the putative mitochondrial K(ATP) channel and/or free radical synthesis, SNAP perfused hearts were also treated with the mitochondrial K(ATP) channel blocker, 5-hydroxy decanoate (5-HD) and the free-radical scavenger, N-(2-mercaptopropionyl)-glycine (MPG). This data was correlated with mitochondrial membrane potential (Delta Psi(m)), measured with the potentiometric dye, tetra-methyl rhodium methyl ester (TMRM), in isolated mitochondria,by flow cytometry. RESULTS: SNAP dose-dependently attenuated infarct size, with maximal protection observed at 2 microM (17+/-4% versus controls 32+/-3%, P<0.01). At greater concentrations however, protection was lost with infarct sizes tending towards control at 20 microM (29+/-3%). These results were paralleled by changes in Delta Psi(m) in the isolated mitochondria: Delta Psi(m) depolarisation peaking with 1 microM SNAP (26+/-4% shift in TMRM fluorescence, P<0.01); at greater concentrations, this relationship was lost. The mitochondrial K(ATP) channel blocker, 5-HD, resulted in both abrogation of SNAP infarct size reduction and concomitant loss of Delta Psi(m) depolarisation in the mitochondria. MPG however did not influence the cardioprotective properties of SNAP. CONCLUSION: We demonstrate that nitric oxide can mediate cardioprotection in a dose-dependent fashion by an effect that may be related to Delta Psi(m). Both cardioprotection and Delta Psi(m) changes are sensitive to 5-HD and the cardioprotection appears independent of free-radical synthesis.

Nitric oxide as a mediator of delayed pharmacological (A(1) receptor triggered) preconditioning; is eNOS masquerading as iNOS?

BACKGROUND: Nitric oxide (NO), synthesised from the inducible isoform of nitric oxide synthase (iNOS), is implicated in mediating second window of protection (SWOP)/delayed ischemic preconditioning. However the role of NO and iNOS in delayed pharmacological protection remains unclear and is the subject of this investigation. METHODS: To test the hypothesis that iNOS is necessary for delayed pharmacological preconditioning, the adenosine A(1) receptor agonist, 2-chloro N(6) cyclopentyl adenosine (CCPA) (25 microg/kg i.v.) or saline was administered to wild type (WT) or iNOS gene knockout mice (KO). Twenty-four hours later, the hearts were isolated, Langendorff perfused and subjected to 35 min ischemia/30 min reperfusion prior to infarct size determination. RESULTS: WT and KO control hearts had identical infarct sizes of 37 +/- 3% and 37 +/- 2%, respectively. CCPA significantly reduced infarct size in WT hearts to 22 +/- 2% and also, unexpectedly, in KO hearts (27 +/- 2%). This protection was abrogated with the non-specific NOS inhibitor, N(omega) nitro L-arginine methyl ester (L-NAME, 100 microM), and could be mimicked in naïve hearts with the NO donor, donor S-nitroso N-acetyl DL penicillamine (SNAP, 1 microM). Delayed protection appeared to be mediated by NO synthesis in both WT and KO hearts. Additional studies using Western blot analysis demonstrated endothelial NOS (eNOS) upregulation and increased NO(x) release in both WT and KO hearts. CONCLUSIONS: This is the first study to demonstrate a role for eNOS in delayed A(1) receptor triggered (pharmacological) preconditioning, potentially representing a new pharmacological target for protecting the ischemic heart.

Implications of Kidney Disease in the Cardiac Patient.

Traditional cardiovascular risk factors, particularly hypertension and diabetes, are common in the disease processes of both renal and cardiac pathology. Unfortunately the coexistence of renal impairment is not an innocent bystander in cardiovascular disease; it disorder not only increases the prevalence and severity of cardiovascular disease, but also negatively affects prognostic outcomes and the safety and efficacy of cardiac interventions. This article discusses the role and impact of kidney disease in the cardiac patient in 3 key common cardiovascular processes: coronary artery disease, arrhythmia, and heart failure.

Effect of remote ischaemic conditioning on contrast-induced nephropathy in patients undergoing elective coronary angiography (ERICCIN): rationale and study design of a randomised single-centre, double-blind placebo-controlled trial.

BACKGROUND: Contrast-induced nephropathy (CIN), an acute kidney injury resulting from the administration of intravascular iodinated contrast media, is an important cause of morbidity/mortality following coronary angiographic procedures in high-risk patients. Despite preventative measures intended to mitigate the risk of CIN, there remains a need for an effective intervention. Remote ischaemic conditioning (RIC), where non-injurious ischaemia is applied to an arm prior to the administration of contrast, has shown promise in attenuating CIN but its effectiveness in preserving long-term renal function is unknown, which will be studied as part of the effect of remote ischaemic conditioning against contrast-induced nephropathy (ERICCIN) trial. ( http://Controlled-trials.com Identifier: ISRCTN49645414.) METHODS: The ERICCIN trial is a single-centre, randomised double-blinded placebo-controlled trial which plans to recruit 362 patients who are at risk of CIN, defined by pre-existent renal impairment (estimated glomerular filtration rate <60 ml/min/1.73 m2), over a period of 2 years. Patients will be randomised to either control or RIC consisting of 4, 5 min 200 mmHg balloon-cuff inflation/deflations, to the upper arm. The primary endpoint will be the development of CIN (>25% of eGFR, or rise of creatinine of >44 µmol/l) at 48 h. A key secondary endpoint will be whether RIC impacts upon persistent renal impairment over the 3-month follow-up period. Additional secondary endpoints include the measurement of serum neutrophil gelatinase-associated lipocalin and urinary albumin at 6, 48 h and 3 months following administration of contrast. IMPLICATIONS: Findings from ERICCIN trial will potentially demonstrate that RIC attenuates contrast-induced acute and chronic kidney injury and influence future clinical practice guidelines in at-risk patients undergoing coronary angiographic procedures.