Ischaemic conditioning and targeting reperfusion injury: a 30 year voyage of discovery.

To commemorate the auspicious occasion of the 30th anniversary of IPC, leading pioneers in the field of cardioprotection gathered in Barcelona in May 2016 to review and discuss the history of IPC, its evolution to IPost and RIC, myocardial reperfusion injury as a therapeutic target, and future targets and strategies for cardioprotection. This article provides an overview of the major topics discussed at this special meeting and underscores the huge importance and impact, the discovery of IPC has made in the field of cardiovascular research.

Hypoxia-reoxygenation-induced endothelial barrier failure: role of RhoA, Rac1 and myosin light chain kinase.

Hypoxia-reoxygenation induces loss of endothelial barrier function and oedema formation, which presents a major impediment for recovery of the organ. The integrity of the endothelial barrier is highly dependent on its contractile machinery and actin dynamics, which are precisely regulated by Rho GTPases. Perturbed activities of these Rho-GTPases under hypoxia-reoxygenation lead to derangement of the actin cytoskeleton and therefore may affect the integrity of the endothelial barrier.

Calcium-mediated cell death during myocardial reperfusion.

Reperfusion may induce additional cell death in patients with acute myocardial infarction receiving primary angioplasty or thrombolysis. Altered intracellular Ca(2+) handling was initially considered an essential mechanism of reperfusion-induced cardiomyocyte death. However, more recent studies have demonstrated the importance of Ca(2+)-independent mechanisms that converge on mitochondrial permeability transition (MPT) and are shared by cardiomyocytes and other cell types.

Opposing effects of ATP and adenosine on barrier function of rat coronary microvasculature.

ATP can differentially affect the micro- and macrovascular endothelial barrier. It has been shown that it can both increase and/or decrease macromolecule permeability of microvascular endothelial cells and microvessels, in vivo. We hypothesised that the barrier stabilising effect is mediated by ATP itself via P2 receptors, while barrier-disrupting effect is mediated by its metabolite adenosine via adenosine receptors.

Intermedin induces loss of coronary microvascular endothelial barrier via derangement of actin cytoskeleton: role of RhoA and Rac1.

Aims: Intermedin (IMD) is a novel member of the calcitonin gene-related peptide family, which acts via calcitonin receptor-like receptors (CLRs), mediating activation of cAMP signalling. The main objective of the present study was to analyse the molecular mechanisms of the differential effects of IMD on the macromolecule permeability of endothelial cells of different vascular beds.

Methods And Results: Here we demonstrate that IMD increases permeability of rat coronary microvascular endothelial cells (RCECs) and reduces permeability of human umbilical vein endothelial cells (HUVECs) and rat aortic endothelial cells via CLRs and cAMP.

TGFβ receptor activation enhances cardiac apoptosis via SMAD activation and concomitant NO release.

Unlabelled: Transforming growth factor β (TGFβ) expression is induced in the myocardium during transition from compensated hypertrophy to heart failure. In cardiomyocytes, stimulation with TGFβ results in restricted contractile function and enhanced apoptosis. Nitric oxide (NO) also induces apoptosis and influences cardiac function.

Insulin stabilizes microvascular endothelial barrier function via phosphatidylinositol 3-kinase/Akt-mediated Rac1 activation.

Objective: Insulin is a key regulator of metabolism, but it also confers protective effects on the cardiovascular system. Here, we analyze the mechanism by which insulin stabilizes endothelial barrier function.

Methods And Results: Insulin reduced basal and antagonized tumor necrosis factor-alpha-induced macromolecule permeability of rat coronary microvascular endothelial monolayers.

cAMP/PKA antagonizes thrombin-induced inactivation of endothelial myosin light chain phosphatase: role of CPI-17.

Aims: Activation of cAMP signalling abrogates thrombin-induced hyperpermeability. One of the mechanisms underlying this protective effect is the inactivation of endothelial contractile machinery, one of the major determinants of endothelial barrier function, mainly via the activation of myosin light chain phosphatase (MLCP). To date, the mechanisms of cAMP-mediated MLCP activation are only partially understood.

Stimulation of cGMP signalling protects coronary endothelium against reperfusion-induced intercellular gap formation.

Aims: Ischaemia-reperfusion provokes barrier failure of the coronary microvasculature, impeding functional recovery of the heart during reperfusion. The aim of the present study was to investigate whether the stimulation of cGMP signalling by activation of soluble guanylyl cyclase (sGC) can reduce reperfusion-induced endothelial intercellular gap formation and to determine whether this is due to an influence on endothelial cytosolic Ca(2+) homeostasis during reperfusion.

Methods And Results: Experiments were performed with cultured coronary endothelial monolayers and isolated saline-perfused rat hearts.

Parathyroid hormone improves contractile performance of adult rat ventricular cardiomyocytes at low concentrations in a non-acute way.

Aims: In patients with congestive heart failure, plasma parathyroid hormone (PTH) levels are positively associated with cardiac function. PTH, used to mobilize stem cells from the bone marrow after myocardial infarction, causes an increased left ventricular ejection fraction. The aim of this study was to investigate whether low but plasma-relevant concentrations of PTH directly influence the contractile properties of cardiomyocytes.

CGRP-alpha responsiveness of adult rat ventricular cardiomyocytes from normotensive and spontaneously hypertensive rats.

Calcitonin gene-related peptide (CGRP)-alpha is expressed in heart ventricles in sensory nerves and cardiomyocytes. It modifies inotropism and induces ischaemic preconditioning. This study investigates the effect of CGRP-alpha on the contractile responsiveness of isolated adult ventricular rat cardiomyocytes and the effect of chronic hypertension on this interaction.

Platelet-derived growth factor BB stimulates vasculogenesis of embryonic stem cell-derived endothelial cells by calcium-mediated generation of reactive oxygen species.

Aims: Platelet-derived growth factor BB (PDGF-BB) has been assigned a critical role in vascular growth and recruitment of perivascular mural cells. The purpose of the present study is to investigate the signalling events underlying the stimulation of vasculogenesis of mouse embryonic stem (ES) cells by PDGF-BB.

Methods And Results: PDGF-BB increased vascular sprouting and branching of capillary-like structures in embryoid bodies as evaluated by computer-assisted analysis of CD31-positive cell structures.

Cytosolic Ca2+ oscillations in human cerebrovascular endothelial cells after subarachnoid hemorrhage.

Molecular mechanisms of cerebral vasospasm after subarachnoid hemorrhage (SAH) include specific modes of cell signaling like activation of nuclear factor (NF)-kappaB and vascular cell adhesion molecules (VCAM)-1 expression. The study's hypothesis is that cisternal cerebral spinal fluid (CSF) from patients after SAH may cause Ca(2+) oscillations which induce these modes of vascular inflammation in an in vitro model of human cerebral endothelial cells (HCECs). HCECs were incubated with cisternal CSF from 10 SAH patients with confirmed cerebral vasospasm.

Angiotensin II-dependent loss of cardiac function: mechanisms and pharmacological targets attenuating this effect.

Pharmacological inhibition of components of the renin-angiotensin-system is one of the major therapeutically options to treat patients with heart failure. This study hypothesized that angiotensin II (Ang II) directly depresses contractile function (cell shortening) by activation of transforming growth factor-beta(1) (TGF-beta(1)). Moreover, we hypothesized that an inhibition of glycogen synthase kinase 3-betaGSK will compensate for this depressive effect by increasing SERCA2 expression.

Importance of bicarbonate transport for ischaemia-induced apoptosis of coronary endothelial cells.

Bicarbonate transport (BT) has been previously shown to participate in apoptosis induced by various stress factors. However, the precise role of BT in ischaemia-induced apoptosis is still unknown. To investigate this subject, rat coronary endothelial cells (EC) were exposed to simulated ischaemia (glucose free anoxia at Ph 6.