Applying systems biology in drug discovery and development.

Translational research is a continuum between clinical and basic research where the patient is the center of the research process. It brings clinical research to a starting point for the drug discovery process, permitting the generation of a more robust pathophysiological hypothesis essential for a better selection of drug targets and candidate optimization. It also establishes the basis of early proof for clinical concept studies, preferably in phase I, for which biomarkers and surrogate endpoints can often be used. Systems biology is a prerequisite approach to translational research where technologies and expertise are integrated and articulated to support efficient and productive realization of this concept. The first component of systems biology relies on omics-based technologies and integrates the changes in variables, such as genes, proteins and metabolites, into networks that are responsible for an organism's normal and diseased state. The second component of systems biology is in the domain of computational methods, where simulation and modeling create hypotheses of signaling pathways, transcription networks, physiological processes or even cell- or organism-based models. The simulations aim to show the origin of perturbations of the system that lead to pathological states and what treatment could be achieved to ameliorate or normalize the system. This review discusses how translational research and systems biology together could improve global understanding of drug targets, suggest new targets and approaches for therapeutics, and provide a deeper understanding of drug effects. Taken together, these types of analyses can lead to new therapeutic options while improving the safety and efficacy of new and existing medications.

Role of innovation in pharmaceutical regulation: A proposal for principles to evaluate EU General Pharmaceutical Legislation from the innovator perspective.

Because the EU General Pharmaceutical Legislation is under review, the EFPIA Innovation Board developed evaluation principles for the policy proposals and key considerations on how the regulatory framework can support innovation while ensuring only safe, efficacious and quality medicines are authorized. The evaluation principles are anchored on actions to promote: agile adoption of new methodologies with soft law tools; continued emphasis on regulatory science to inform policies; a cost/benefit assessment of the new regulation to ensure they have an overall positive impact; and mitigation of any negative externalities or unintended effects for any type of innovation or products. The evaluation principles are intended to guide the impact assessment of the pharmaceutical legislation in the EU but the principles can be applied globally.

RhoA guanine exchange factor expression profile in arteries: evidence for a Rho kinase-dependent negative feedback in angiotensin II-dependent hypertension.

Sustained overactivation of RhoA is a common component for the pathogenesis of several cardiovascular disorders, including hypertension. Although activity of Rho proteins depends on Rho exchange factors (Rho-GEFs), the identity of Rho-GEFs expressed in vascular smooth muscle cells (VSMC) and participating in the control of Rho protein activity and Rho-dependent functions remains unknown. To address this question, we analyzed by quantitative RT-PCR the expression profile of 28 RhoA-GEFs in arteries of normotensive (saline-treated) and hypertensive (ANG II-treated) rats. Sixteen RhoA-GEFs were downregulated in mesenteric arteries of hypertensive rats, among which nine are also downregulated in cultured VSMC stimulated by ANG II (100 nM, 48 h), suggesting a direct effect of ANG II. Inhibition of type 1 ANG II receptors (losartan, 1 µM) or Rho kinase (fasudil, 10 µM) prevented ANG II-induced RhoA-GEF downregulation. Functionally, ANG II-induced downregulation of RhoA-GEFs is associated with decreased Rho kinase activation in response to endothelin-1, norepinephrine, and U-46619. This work thus identifies a group of RhoA-GEFs that controls RhoA and RhoA-dependent functions in VSMC, and a negative feedback of RhoA/Rho kinase activity on the expression of these RhoA-GEFs that may play an adaptative role to limit RhoA/Rho kinase activation.

Toward A Regulatory Pathway for the Use of in Silico Trials in the CE Marking of Medical Devices.

In Silico Trials methodologies will play a growing and fundamental role in the development and de-risking of new medical devices in the future. While the regulatory pathway for Digital Patient and Personal Health Forecasting solutions is clear, it is more complex for In Silico Trials solutions, and therefore deserves a deeper analysis. In this position paper, we investigate the current state of the art towards the regulatory system for in silico trials applied to medical devices while exploring the European regulatory system toward this topic. We suggest that the European regulatory system should start a process of innovation: in principle to limit distorted quality by different internal processes within notified bodies, hence avoiding that the more innovative and competitive companies focus their attention on the needs of other large markets, like the USA, where the use of such radical innovations is already rapidly developing.

Implication of microRNAs in the cardiovascular system.

MicroRNAs (miRNAs) are endogenous, small, noncoding RNAs that regulate about 30% of protein-coding genes of the human genome. Thus far, more than 400 miRNAs have been cloned and sequenced in humans. Their biological importance, initially demonstrated in cancer, viral diseases and developmental processes, was more recently investigated in cardiovascular physiology and pathology. MiRNAs expression is tightly controlled in a tissue-specific and developmental stage-specific manner and some of them are highly and specifically expressed in cardiovascular tissues. Through the regulation of the expression of genes involved in cell growth, contractility and electrical conductance, cardiac miRNAs may play a major role in heart development and function. In vascular cells, miRNAs have been linked to vasculoproliferative conditions such as angiogenesis and neointimal lesion formation. Diagnostic use and therapeutic modulation of individual miRNAs or miRNA clusters in cardiovascular diseases will have to be further explored in the future. Molecules specifically regulating cardiovascular miRNAs, either mimicking or antagonizing miRNAs actions, will hopefully normalize dysfunctional gene networks and constitute a new therapy paradigm of cardiovascular diseases.

Rho exchange factors in the cardiovascular system.

Increasing evidence has accumulated to implicate overactivation of Rho protein as a common component for the pathogenesis of several cardiovascular disorders including hypertension, coronary and cerebral vasospasm, atherosclerosis, and diabetes. Recent advances in Rho protein signaling research indicate that the Rho exchange factors (Rho GEFs) which activate Rho proteins by catalyzing the exchange of GDP for GTP are major regulators of Rho protein activity. In addition, linkage analysis and association studies have recently identified Rho GEFs as susceptibility genes for cardiovascular diseases. All of these data are converging to suggest that as upstream activators of Rho proteins, Rho GEFs expressed in cardiovascular cells are good candidate targets for the treatment of cardiovascular disorders.

[The Innovative Medicine Initiative (IMI)]. / L'Initiative Médicaments Innovants : développement de l'innovation biomédicale en Europe.

The Innovative Medicine Initiative (IMI) is a joint technology initiative jointly implemented by the European Commission and by the European Federation of Pharmaceutical Industries and Associations (EFPIA). The objective of IMI, officially launched on April 30th 2008, is to identify and address the bottlenecks of the drug discovery and development process. IMI will reinforce the public-private partnerships and will be focused towards critical nodes of the drug discovery such as efficacy predictivity, safety predictivity, knowledge management and education and training. This initiative will also reinforce the attractivity of Europe for biomedical science and will then lead to the discovery of novel therapeutic strategies for the patients.

[Cardiac lymphatic system]. / Le système lymphatique cardiaque.

The lymphatic system is a network of vessels and lymphoid tissues that maintain tissue fluid homeostasis, transport intestinal fat, and regulate immune surveillance. Despite a large body of evidence showing the importance of lymphatic vessels in cardiovascular diseases, the role of cardiac lymphatics has not been extensively investigated. This review highlights the chronology of key discoveries in cardiac lymphatic development and function. In physiology, the cardiac lymphatic system dynamically regulates interstitial fluid drainage to the mediastinal lymph nodes to maintain homeostasis and prevent edema. After myocardial infarction, lymphatic vessels in the ischemic heart become dysfunctional and contribute to the development of chronic myocardial edema that aggravates cardiac fibrosis and dysfunction. Stimulation of cardiac lymphangiogenesis, based on the delivery of lymphangiogenic growth factors, such as VEGF-C, may represent a novel therapeutic strategy to improve cardiac function.

Rosiglitazone, a peroxisome proliferator-activated receptor-gamma, inhibits the Jun NH(2)-terminal kinase/activating protein 1 pathway and protects the heart from ischemia/reperfusion injury.

This study was conducted to evaluate whether treatment of normal and diabetic rat hearts with rosiglitazone, a high-affinity ligand of the peroxisome proliferator-activated receptor-gamma (PPAR-gamma) used for the treatment of type 2 diabetes, improves postischemic functional recovery. The effects of acute rosiglitazone administration were investigated using working hearts isolated from normal rat or rats diabetic for 4 weeks after streptozotocin (STZ) injection. Hearts were subjected to 30 min of normothermic, zero-flow ischemia followed by 30-min reperfusion. Rosiglitazone (1 micromol/l) administered before ischemia had no effect on cardiac function during baseline perfusion, but it significantly improved aortic flow during reperfusion in both normal and diabetic hearts. In a chronic protocol in which rosiglitazone was given by daily gavage (10 micromol/kg body wt) immediately after STZ injection, rosiglitazone also prevented postischemic injury and significantly improved functional recovery. Using Western immunoblotting, it was demonstrated that the acute cardioprotective effect of rosiglitazone is associated with an inhibition of Jun NH(2)-terminal kinase phosphorylation in both normal and diabetic rat hearts. Furthermore, rosiglitazone also inhibited activating protein-1 DNA-binding activity. These data, demonstrating that rosiglitazone limits postischemic injury in isolated hearts, suggest an important function for PPAR-gamma in the heart.

Recent advances in arrhythmia therapy: treatment and prevention of atrial fibrillation.

Current therapy for atrial fibrillation is divided into rhythm control agents and rate control agents. Although class III antiarrhythmic agents are being used increasingly for both conversion of atrial fibrillation to sinus rhythm and prevention of recurrence, most pharmacological approaches under active investigation, including azimilide and dronedarone, are compounds with multiple electrophysiological actions. Based on the current knowledge of the mechanisms involved in atrial fibrillation initiation and maintenance, novel approaches targeting the intracellular calcium overload are being investigated.

[Ageing: a matter of heart?]. / Vieillissement - Une question de cœur ?

Ageing is considered as a major risk factor for the development of chronic diseases. Among these, heart failure seems to be particularly important for both triggering and accelerating pathological ageing. In the present review, we give a general overview of the most relevant results concerning the mechanism of normal and premature senescence of cardiomyocytes and cardiac stromal cells. In particular, we will address the role of telomere dysfunction, DNA damage response, impairment of mitochondrial function, miRNAs and secretome of senescent cells in cardiac ageing and failure.

Late neointimal tissue growth behind the stent after intravascular gamma-radiation.

PURPOSE: To determine the nature of the changes of the vascular wall after intravascular brachytherapy in stented arteries leading to incomplete stent apposition. METHODS AND MATERIALS: Stents were implanted in the infrarenal aortas of rabbits, and gamma-intravascular brachytherapy (18 Gy) or a sham radiation procedure was immediately implemented. The arteries were harvested at 6 months for histologic analyses. RESULTS: The external elastic lamina area, as well as the vascular wall area behind the stent, were significantly greater in irradiated vs. control arteries (8.94 +/- 0.68 mm2 vs. 6.87 +/- 0.40 mm2 [p <0.001] and 1.56 +/- 0.13 mm2 vs. 0.72 +/- 0.07 mm2 [p <0.001], respectively). The ratio of the intimal area behind the stent related to the total intimal area was greater in the irradiated segments (control vs. irradiated: 9.0% +/- 5.9% vs. 55.3% +/- 15.5%, p <0.05). Neointimal growth of the irradiated vessels outside the stent was characterized by marked fibrin depositions and an inflammatory response around the stent struts. CONCLUSION: Our study revealed the presence of a neointimal layer specifically located behind the stent, which represented the result of an unhealed fibrin-rich tissue growth process 6 months after intravascular brachytherapy.

Protection from myocardial stunning by ischaemia and hypoxia with the adenosine A3 receptor agonist, IB-MECA.

Guinea pig isolated working hearts were exposed to 30-min ischaemia by reducing coronary flow to 10%, followed by reperfusion. Aortic output fell to 4.5+/-4.5% of the pre-ischaemic value at reperfusion, recovering to 48.2+/-14.6% at 20-min post-reperfusion; the index of myocardial stunning. IB-MECA (N(6)-(3-iodobenzyl)adenosine-5'-N-methyluronamide, 3 x 10(-7) M), infused from 10 min into ischaemia, did not affect recovery of aortic output 20 min after reperfusion (41.9+/-1.9%). IB-MECA infused at reperfusion, however, significantly protected against stunning, aortic output recovering to 79.6+/-3.9% at 20-min post-reperfusion. Hypoxic gassing (5% CO(2) in nitrogen, 30 min) of guinea pig isolated paced left atria and papillary muscles reduced the developed tension, recovering to 75% 5 min after re-oxygenation. This myocardial stunning was unaffected by IB-MECA (3 x 10(-7) M) added 10 min into hypoxia. IB-MECA added at reoxygenation significantly improved recovery, which was prevented by the adenosine A(3) receptor antagonist, 1-propyl-3-(3-iodo-4-aminobenzyl)-8-(4-oxyacetate)phenylxanthine (I-ABOPX, 1 x 10(-5) M). Thus, stimulation of adenosine A(3) receptors at reperfusion/reoxygenation in guinea pig cardiac preparations protects against myocardial stunning.

Effects of adenosine receptor agonists on guinea-pig isolated working hearts and the role of endothelium and NO.

The hypothesis that the coronary vasodilator effects of adenosine receptor agonists are independent of the vascular endothelium or mediators derived therefrom was examined in guinea-pig isolated working hearts. Adenosine receptor agonists, 5'-(N-ethylcarboxamido)-adenosine (NECA; two-fold selective for A2 over A1 receptors), 2-[p-(2-carboxyethyl)phenylethylamino]-5'-N-ethylcarboxamidoadenosine (CGS21680; A2A selective), N6-cyclopentyl-adenosine (CPA; A1 selective) and N6-(3-iodobenzyl)adenosine-5'-N-methyluronamide (IB-MECA; A3 selective), were infused (3 x 10(-7) M) after endothelium removal by passing oxygen through the coronary circulation. In spontaneously beating hearts, CGS21680 and NECA increased, while CPA decreased, coronary flow. NECA and CPA reduced heart rate, left ventricular pressure and aortic output. The nitric oxide synthase (NOS) inhibitor, N(G)-nitro-L-arginine (L-NOARG; 3 x 10(-5) M) abolished the vasodilatation by NECA but not CGS21680, indicating that nitric oxide (NO) of a non-endothelial source mediated the NECA response. Coronary vasodilatation by CGS21680 was inhibited bythe A2A receptor antagonist, 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo [2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (ZM241385). Indometacin (10(-6) M) attenuated the coronary vasodilatation to CGS21680, suggesting a partial role for cyclooxygenase products. IB-MECA had no effect, indicating no A3 receptor involvement. In paced working hearts, the responses were similar except CPA had no effect on coronary flow or aortic output and CGS21680 increased left ventricular pressure and the maximum rate of ventricular pressure rise. This study has demonstrated functionally effective removal of the endothelium by a novel method of passing oxygen through the coronary vasculature. A coronary vasodilator action of adenosine receptor agonists mediated via A2A receptors is endothelium- and NO-independent, but partially involves cyclooxygenase products.

Beneficial effects of direct call to emergency medical services in acute myocardial infarction.

OBJECTIVES: We investigated the impact of an emergency medical services call on the management of acute myocardial infarction, considering time intervals for intervention and revascularization procedures. METHODS: Data were prospectively collected from January 2001 to October 2002 from 531 patients hospitalized for myocardial infarction with ST segment elevation and a pre-hospital delay of less than 24 h. RESULTS: Only 26% of patients called the emergency medical services at the onset of symptoms (n=140). Other patients (n=391, 74%) called another medical contact. Baseline characteristics and cardiovascular history were similar in the two groups, except for the percutaneous coronary intervention history (10% in the emergency medical services group versus 4% in the other medical contact group, P<0.05). Time intervals from the onset of symptoms of myocardial infarction to call or to medical intervention, as well as the time interval from medical intervention to hospital admission were significantly shorter in the emergency medical services group. The early reperfusion rate was also significantly greater in the emergency medical services group (77%) compared with the other medical contact group (64%), mainly because of a greater incidence of primary percutaneous coronary intervention (36 versus 26%, P<0.03, respectively). Multivariate analysis adjusted for sex and age showed that less than three medical care providers [odds ratio (OR) 5.042, P<0.001], percutaneous coronary intervention history (OR 2.462, P<0.05), as well as rhythmic disorders (OR 2.105, P<0.05) and complete atrioventricular block (OR 2.757, P<0.05) were independent predictors of emergency medical services care. CONCLUSION: This study demonstrated that a call to the emergency medical services is underutilized by patients with symptoms of myocardial infarction, and documented the beneficial effects of an emergency medical services call by reducing pre-hospital delays and increasing early revascularization therapies.