Aspirin suppresses cardiac fibroblast proliferation and collagen formation through downregulation of angiotensin type 1 receptor transcription

Aspirin (acetyl salicylic acid, ASA) is a common drug used for its analgesic and antipyretic effects. Recent studies show that ASA not only blocks cyclooxygenase, but also inhibits NADPH oxidase and resultant reactive oxygen species (ROS) generation, a pathway that underlies pathogenesis of several ailments, including hypertension and tissue remodeling after injury. In these disease states, angiotensin II (Ang II) activates NADPH oxidase via its type 1 receptor (AT1R) and leads to fibroblast growth and collagen synthesis. In this study, we examined if ASA would inhibit NADPH oxidase activation, upregulation of AT1R transcription, and subsequent collagen generation in mouse cardiac fibroblasts challenged with Ang II. Mouse heart fibroblasts were isolated and treated with Ang II with or without ASA. As expected, Ang II induced AT1R expression, and stimulated cardiac fibroblast growth and collagen synthesis. The AT1R blocker losartan attenuated these effects of Ang II. Similarly to losartan, ASA, and its SA moiety suppressed Ang II-mediated AT1R transcription and fibroblast proliferation as well as expression of collagens and MMPs. ASA also suppressed the expression of NADPH oxidase subunits (p22(phox), p47(phox), p67(phox), NOX2 and NOX4) and ROS generation. ASA did not affect total NF-κB p65, but inhibited its phosphorylation and activation. These observations suggest that ASA inhibits Ang II-induced NADPH oxidase expression, NF-κB activation and AT1R transcription in cardiac fibroblasts, and fibroblast proliferation and collagen expression. The critical role of NADPH oxidase activity in stimulation of AT1R transcription became apparent in experiments where ASA also inhibited AT1R transcription in cardiac fibroblasts challenged with H2O2. Since SA had similar effect as ASA on AT1R expression, we suggest that ASA's effect is mediated by its SA moiety.

The contribution of oxidative stress to drug-induced organ toxicity and its detection in vitro and in vivo

INTRODUCTION

Nowadays the 'redox hypothesis' is based on the fact that thiol/disulfide couples such as glutathione (GSH/GSSG), cysteine (Cys/CySS) and thioredoxin ((Trx-(SH)2/Trx-SS)) are functionally organized in redox circuits controlled by glutathione pools, thioredoxins and other control nodes, and they are not in equilibrium relative to each other. Although ROS can be important intermediates of cellular signaling pathways, disturbances in the normal cellular redox can result in widespread damage to several cell components. Moreover, oxidative stress has been linked to a variety of age-related diseases. In recent years, oxidative stress has also been identified to contribute to drug-induced liver, heart, renal and brain toxicity.

AREAS COVERED

This review provides an overview of current in vitro and in vivo methods that can be deployed throughout the drug discovery process. In addition, animal models and noninvasive biomarkers are described.

EXPERT OPINION

Reducing post-market drug withdrawals is essential for all pharmaceutical companies in a time of increased patient welfare and tight budgets. Predictive screens positioned early in the drug discovery process will help to reduce such liabilities. Although new and more efficient assays and models are being developed, the hunt for biomarkers and noninvasive techniques is still in progress.

Marine carotenoids and oxidative stress

Oxidative stress induced by reactive oxygen species plays an important role in the etiology of many diseases. Dietary phytochemical products, such as bioactive food components and marine carotenoids (asthaxantin, lutein, β-carotene, fucoxanthin), have shown an antioxidant effect in reducing oxidative markers stress. Scientific evidence supports the beneficial role of phytochemicals in the prevention of some chronic diseases. Many carotenoids with high antioxidant properties have shown a reduction in disease risk both in epidemiological studies and supplementation human trials. However, controlled clinical trials and dietary intervention studies using well-defined subjects population have not provided clear evidence of these substances in the prevention of diseases. The most important aspects of this special issue will cover the synthesis, biological activities, and clinical applications of marine carotenoids, with particular attention to recent evidence regarding anti-oxidant and anti-inflammatory properties in the prevention of cardiovascular disease.

Increased leukocyte Rho-associated coiled-coil containing protein kinase activity predicts the presence and severity of coronary vasospastic angina

OBJECTIVE

Although inhibition of Rho-associated coiled-coil containing protein kinase (ROCK) has been shown to prevent coronary vasospastic angina (CVA), direct evidence linking ROCK activity and CVA is lacking. Accordingly, we investigated whether ROCK activity is an independent marker for CVA and is altered after treatment with antispastic medications.

METHODS AND RESULTS

We prospectively studied 31 Taiwanese patients who were diagnosed with CVA and 33 control subjects. Subject demographics were recorded, and blood samples were obtained at baseline in all participants and in CVA patients after 3 months of antispastic treatment. Compared with control subjects, leukocyte ROCK activity was greater in CVA patients (136% versus 91%, P<0.001). A cutoff value for leukocyte ROCK activity of 104% predicted the presence of CVA with specificity and sensitivity rates of 88% and 84%, respectively. ROCK activity increased with the severity of CVA (P for trend<0.001). Following 3-month treatment of antispastic agents, leukocyte ROCK activity, high-sensitivity C-reactive protein, and interleukin-6 levels were reduced by 43%, 42% and 27%, respectively (P<0.05 for all).

CONCLUSIONS

Increased levels of leukocyte ROCK activity independently predicted the presence of CVA and correlated with CVA severity. Treatment with antispastic agents substantially reduced the level of leukocyte ROCK activity.

Involvement of upper torso stress amplification, tissue compression and distortion in the pathogenesis of keloids

Keloids are benign tumours composed of fibrous tissue produced during excessive tissue repair triggered by minor injury, trauma or surgical incision. Although it is recognized that keloids have a propensity to form in the upper torso of the body, the predisposing factors responsible for this have not been investigated. It is crucial that the aetiopathoical factors implicated in keloid formation be established to provide guidelines for well-informed more successful treatment. We compared keloid-prone and keloid-protected skin, identified pertinent morphological differences and explored how inherent structural characteristics and intrinsic factors may promote keloid formation. It was determined that keloid prone areas were covered with high tension skin that had low stretch and a low elastic modulus when compared with skin in keloid protected areas where the skin was lax with a high elastic modulus and low pre-stress level. Factors contributing to elevated internal stress in keloid susceptible skin were the protrusion of hard connective tissue such as bony prominences or cartilage into the dermis of skin as well as inherent skin characteristics such as the bundled arrangement of collagen in the reticular dermis, the existent high tension, the low elastic modulus, low stretch ability, contractile forces exerted by wound healing fibroblastic cells and external forces. Stress promotes keloid formation by causing dermal distortion and compression which subsequently stimulate proliferation and enhanced protein synthesis in wound healing fibroblastic cells. The strain caused by stress also compresses and occludes microvessels causing ischaemic effects and reperfusion injury which stimulate growth when blood rich in growth factors returns to the tissue. The growth promoting effects of increased internal stress, primarily, and growth factors released by reperfusing blood, manifest in keloid formation. Other inherent skin characteristics promoting keloid growth during the late stages of wound healing in the upper torso are the thinner epidermis, the presence of vellus hairs, the absence of protective immunoglobulin A (IgA), and the thick fragile quality of upper torso skin. As it is not known why there is a predilection for keloids to form in the upper torso of the body, this hypothesis implicating and associating inherent morphological characteristics and elevated stress in the aetiopathogenesis of keloids is of potential value in terms of prevention, management and treatment of these enigmatic tumours.

Assessment of left atrial dysfunction in obstructive sleep apnea patients with the two dimensional speckle-tracking echocardiography

BACKGROUND

The aim of this study was to compare left atrial (LA) longutidinal myocardial function in obstructive sleep apnea (OSA) patients with healthy individuals using two-dimensional speckle-tracking echocardiography method (2D-STE).

METHOD

Twenty one healthy individuals and 58 OSA patients were included. According to the AHI (apnea hypopnea index) patients were examined in mild, moderate and severe OSA groups. Images of the LA were acquired from the apical two- and four-chamber views. LA strain(LA(S)) and strain rate(LA(SR)) parameters [systolic (S), early diastolic (E), late diastolic (A) during atrial contraction] were assessed.

RESULTS

LA(S-S), LA(SR-S), LA(S-E) and LA(SR-E) values decreased with severity of OSA. Severe OSA patients have lower LA(S-S) and LA(SR-S) values (p < 0.03). While a difference in the LA(SR-E) value between groups was significant beginning with the moderate OSA group (p < 0.03), no LA(S-E) value differences were observed between moderate and mild OSA groups (p > 0.03). LA(S-A) and LA(SR-A) values were increasing with the disease severity up to moderate OSA. LA(S-A) and LA(SR-A) values of moderate OSA were greater than the mild OSA patients and healthy individuals (p < 0.03). These were lower in severe OSA than the moderate OSA (p < 0.03), however, they were greater than the healthy individuals (p < 0.03). The AHI was found to be negatively correlated with the LA(S-S), LA(SR-S) LA(S-E), LA(SR-E), whereas AHI was not correlated with the LA(S-A), LA(SR-A) values.

CONCLUSION

LA remodeling and dysfunction that accompany OSA can be detected in the subclinical stage with a detailed evaluation of active and passive functions of the LA using the 2D-STE method.

Hypertrophic cardiomyopathy: from mutation to functional analysis of defective protein

Aim

To analyze the genesis of hypertrophic cardiomyopathy on a large cohort of patients from molecular genetics point of view and perform the functional analysis of the 3D molecular model of defective myosin-7 protein in silico.

Methods

The study enrolled 153 patients with diagnosed hypertrophic cardiomyopathy from different parts of the Czech Republic. DNA samples were analyzed for mutations in exons 21 and 22 of the MYH7 gene, which have been associated with high mutation clustering. The 3D model of human myosin-7 was built using the x-ray structure of nucleotide-free scallop myosin S1 as the structural template. We performed de novo structure prediction of mutant and wild type peptides spanning the 769-788 amino acids region of the myosin-7 protein.

Results

The Arg⁸⁷⁰His and Asp⁷⁷⁸Val amino acid alterations were found in 2 unrelated patients with a severe form of hypertrophic cardiomyopathy. The Asp⁷⁷⁸Val variation was chosen for subsequent 3D molecular modeling in silico. The mutation of the Asp by Val not only changes the character of the interaction pattern with other amino acids or ions but Val, being a small hydrophobic amino acid, can also completely change the stability of the region.

Conclusion

Mutation location in the MYH7 gene and changes in amino acid composition may have a crucial negative impact on the outcome of the disease in patients with hypertrophic cardiomyopathy. In addition, a mutation that changes the charge of the amino acid is more likely to affect protein function than a conservative mutation.

The importance of diabetes mellitus in the global epidemic of cardiovascular disease: the case of the state of Qatar

As a manifestation of the epidemiologic transition being experienced throughout the developing world, the prevalence of diabetes mellitus (DM) is increasing. However, whether an individual's risk of cardiovascular diseases as a consequence of DM is also higher in these countries is unknown. We conducted a case-control study at the medical center in the state of Qatar comparing the prevalence of DM in 512 patients who were admitted with acute myocardial infarctions (MI) and 262 cases of cerebrovascular accidents (CVA) to 382 hospital and outpatient controls to calculate the odds ratios (OR) associated with DM for MI and CVA. The OR for MI was estimated to be 4.01 compared to 2.92 for other countries in the Middle East and 1.75 for North America. The OR was even higher for Qatari natives. Understanding the reasons for this increase, including genetic differences, lifestyle, and medical management issues, is critical for the design and prioritization of effective interventions.

Myocardial infarct size and area at risk assessment in mice

Mouse models of myocardial ischemia and infarction are important in cardiovascular research. Reliable and reproducible assessment of the area at risk (AAR) and infarct size (IS) in mice is vital for deciphering mechanisms behind these common diseases, and for developing and evaluating treatment strategies. The present review will briefly describe and discuss the most common methods for determining the AAR and IS in mouse models of cardiovascular disease. Several methods exist for ex vivo assessment of IS. Conventional histological stains target the fibrous scar and require several days to pass from the time of infarct induction until the animal is euthanized, whereas triphenyltetrazolium-based techniques stain the viable tissue surrounding the infarct and can be performed on tissue harvested within a few hours after infarction. The AAR is usually stained by injecting a dye into the circulation. This dye subsequently distributes to perfused tissue but leaves the AAR unstained. In vivo assessment enables serial measurements of the IS and/or AAR and is sometimes preferable to ex vivo techniques. Echocardiography is usually the method of choice but magnetic resonance imaging-based techniques are also used. The aim of the present review was to provide basic researchers with an introduction to the various techniques used to assess and quantify the IS and AAR in experimental mouse models of myocardial ischemia-reperfusion and infarction.

Fatty Acid Oxidation and Cardiovascular Risk during Menopause: A Mitochondrial Connection?

Menopause is a consequence of the normal aging process in women. This fact implies that the physiological and biochemical alterations resulting from menopause often blur with those from the aging process. It is thought that menopause in women presents a higher risk for cardiovascular disease although the precise mechanism is still under discussion. The postmenopause lipid profile is clearly altered, which can present a risk factor for cardiovascular disease. Due to the role of mitochondria in fatty acid oxidation, alterations of the lipid profile in the menopausal women will also influence mitochondrial fatty acid oxidation fluxes in several organs. In this paper, we propose that alterations of mitochondrial bioenergetics in the heart, consequence from normal aging and/or from the menopausal process, result in decreased fatty acid oxidation and accumulation of fatty acid intermediates in the cardiomyocyte cytosol, resulting in lipotoxicity and increasing the cardiovascular risk in the menopausal women.

Cell biology of ischemia/reperfusion injury

Disorders characterized by ischemia/reperfusion (I/R), such as myocardial infarction, stroke, and peripheral vascular disease, continue to be among the most frequent causes of debilitating disease and death. Tissue injury and/or death occur as a result of the initial ischemic insult, which is determined primarily by the magnitude and duration of the interruption in the blood supply, and then subsequent damage induced by reperfusion. During prolonged ischemia, ATP levels and intracellular pH decrease as a result of anaerobic metabolism and lactate accumulation. As a consequence, ATPase-dependent ion transport mechanisms become dysfunctional, contributing to increased intracellular and mitochondrial calcium levels (calcium overload), cell swelling and rupture, and cell death by necrotic, necroptotic, apoptotic, and autophagic mechanisms. Although oxygen levels are restored upon reperfusion, a surge in the generation of reactive oxygen species occurs and proinflammatory neutrophils infiltrate ischemic tissues to exacerbate ischemic injury. The pathologic events induced by I/R orchestrate the opening of the mitochondrial permeability transition pore, which appears to represent a common end-effector of the pathologic events initiated by I/R. The aim of this treatise is to provide a comprehensive review of the mechanisms underlying the development of I/R injury, from which it should be apparent that a combination of molecular and cellular approaches targeting multiple pathologic processes to limit the extent of I/R injury must be adopted to enhance resistance to cell death and increase regenerative capacity in order to effect long-lasting repair of ischemic tissues.

Pneumococcal Pyopericardium Masquerading as Acute Coronary Syndrome

A 54-year-old man was admitted with a one-week history of chest pain, increasing in severity and worsening dyspnoea. An ECG revealed changes consistent with an acute coronary syndrome (ACS) and a chest X-ray showed an enlarged cardiac shadow. Following admission to the coronary care unit for treatment of presumed ACS his condition deteriorated. A diagnosis of sepsis was made. A CT scan revealed a large pericardial and bilateral pleural effusions. Heart sounds were muffled and neck veins distended, suggesting pericardial tamponade. Echocardiography showed a global pericardial effusion ranging from 2–4 cm with haemodynamic compromise. Sub-xiphisternal pericardiocentesis revealed frank pus from the pericardial cavity and a total of 1,000 mL drained over 48 hours. Rapid haemodynamic improvement ensued. Streptococcus pneumoniae was isolated and the patient was successfully treated with intravenous antibiotics with no requirement for pericardial surgery. In the developed world acute purulent pericarditis is a rare entity with a high mortality rate. Only 10–20% of cases are diagnosed ante-mortem. The condition requires prompt recognition and immediate intervention. The diagnostic picture in this case was initially clouded by the suspicion of ischaemic coronary disease as well as the presence of sepsis. The presentation, management and risk factors associated with this unusual condition are discussed.

The link between metabolic abnormalities and endothelial dysfunction in type 2 diabetes: an update

Despite abundant clinical evidence linking metabolic abnormalities to diabetic vasculopathy, the molecular basis of individual susceptibility to diabetic vascular complications is still largely undetermined. Endothelial dysfunction in diabetes-associated vascular complications is considered an early stage of vasculopathy and has attracted considerable research interests. Type 2 diabetes is characterized by metabolic abnormalities, such as hyperglycemia, excess liberation of free fatty acids (FFA), insulin resistance and hyperinsulinemia. These abnormalities exert pathological impact on endothelial function by attenuating endothelium-mediated vasomotor function, enhancing endothelial apoptosis, stimulating endothelium activation/endothelium-monocyte adhesion, promoting an atherogenic response and suppressing barrier function. There are multiple signaling pathways contributing to the adverse effects of glucotoxicity on endothelial function. Insulin maintains the normal balance for release of several factors with vasoactive properties. Abnormal insulin signaling in the endothelium does not affect the whole-body glucose metabolism, but impairs endothelial response to insulin and accelerates atherosclerosis. Excessive level of FFA is implicated in the pathogenesis of insulin resistance. FFA induces endothelial oxidative stress, apoptosis and inflammatory response, and inhibits insulin signaling. Although hyperglycemia, insulin resistance, hyperinsulinemia and dyslipidemia independently contribute to endothelial dysfunction via various distinct mechanisms, the mutual interactions may synergistically accelerate their adverse effects. Oxidative stress and inflammation are predicted to be among the first alterations which may trigger other downstream mediators in diabetes associated with endothelial dysfunction. These mechanisms may provide insights into potential therapeutic targets that can delay or reverse diabetic vasculopathy.

Dose-dependent artifact in the far wall of the carotid artery at dynamic contrast-enhanced US

PURPOSE

To quantify a pseudoenhancement phenomenon observed during dynamic contrast material-enhanced ultrasonography (US) of the carotid artery, both in vitro and in vivo.

MATERIALS AND METHODS

Ethical approval was obtained prior to commencing this prospective case series, and each patient gave written informed consent. Thirty-one patients with 50%-99% internal carotid artery stenosis underwent dynamic contrast-enhanced US of the carotid bifurcation with use of 2 mL of microbubbles. In the final 10 patients, an additional 1 mL bolus was administered after 15 minutes. Raw linear digital imaging and communications in medicine data were analyzed offline. Regions of interest were drawn within the common carotid artery lumen and immediately adjacent to the lumen in the near and far wall adventitia. Peak intensity was measured. An in vitro experiment with a single-channel flow phantom was also performed. This apparatus consisted of an 8-mm-diameter latex tube placed in a tissue-mimicking fluid. Microbubble concentrations of 0.02%, 0.1%, 0.5%, 1%, and 2% were pumped into the tube. Regions of interest were drawn in a similar fashion to the in vivo experiments, and peak intensity was measured. The Wilcoxon signed rank and paired t tests were used to compare the difference between the near and far wall signal intensities at each dose; a multiplication factor comparing near and far wall signal intensity was derived.

RESULTS

The far wall of the common carotid artery was significantly more echogenic than the near wall at 2 mL contrast agent doses (P<.0001, n=31), and the far wall signal intensity increased synchronously with that of the lumen. The difference in signal intensity between near and far wall regions was significantly greater at 2 mL than at 1 mL (P=.012, n=10). In vitro, the phantom tubing demonstrated a similar pattern and magnitude of enhancement to that seen in vivo.

CONCLUSION

A dose-dependent, nonlinear propagation artifact known as pseudoenhancement occurs in the far wall adventitia of the carotid artery and should not be mistaken as a marker of plaque vulnerability.

Resolution of mitochondrial oxidative stress rescues coronary collateral growth in Zucker obese fatty rats

OBJECTIVE

We have previously found abrogated ischemia-induced coronary collateral growth in Zucker obese fatty (ZOF) rats compared with Zucker lean (ZLN) rats. Because ZOF rats have structural abnormalities in their mitochondria suggesting dysfunction and also show increased production of O(2), we hypothesized that mitochondrial dysfunction caused by oxidative stress impairs coronary collateral growth in ZOF.

METHODS AND RESULTS

Increased levels of reactive oxygen species were observed in aortic endothelium and smooth muscle cells in ZOF rats compared with ZLN rats. Reactive oxygen species levels were decreased by the mitochondria-targeted antioxidants MitoQuinone (MQ) and MitoTempol (MT) as assessed by MitoSox Red and dihydroethidine staining. Lipid peroxides (a marker of oxidized lipids) were increased in ZOF by ≈47% compared with ZLN rats. The elevation in oxidative stress was accompanied by increased antioxidant enzymes, except glutathione peroxidase-1, and by increased uncoupling protein-2 in ZOF versus ZLN rats. In addition, elevated respiration rates were also observed in the obese compared with lean rats. Administration of MQ significantly normalized the metabolic profiles and reduced lipid peroxides in ZOF rats to the same level observed in lean rats. The protective effect of MQ also suppressed the induction of uncoupling protein-2 in the obese rats. Resolution of mitochondrial oxidative stress by MQ or MT restored coronary collateral growth to the same magnitude observed in ZLN rats in response to repetitive ischemia.

CONCLUSIONS

We conclude that mitochondrial oxidative stress and dysfunction play a key role in disrupting coronary collateral growth in obesity and the metabolic syndrome, and elimination of the mitochondrial oxidative stress with MQ or MT rescues collateral growth.

Severe thrombocytopenia following tirofiban infusion

A 44-year-old man presented with acute coronary syndrome. He was administered glycoprotein IIb/IIIa receptor antagonist (tirofiban) for a left anterior descending artery thrombus detected during percutaneous coronary intervention. He developed very severe thrombocytopenia 24 h after tirofiban infusion with no signs of bleeding. The thrombocytopenia spontaneously resolved after stopping tirofiban without any significant clinical sequelae. To our knowledge, this is the first case report of tirofiban-induced severe thrombocytopenia from the Middle East. Clinicians using this drug should be aware of this potentially lethal adverse drug reaction. Close monitoring of platelet count early after the initiation of tirofiban infusion is suggested and discontinuation of tirofiban infusion can reverse thrombocytopenia spontaneously.

Platelet function profile post-clopidogrel therapy in patients with type 2 diabetes undergoing coronary stent implantation

Platelet dysfunction contributes to the increased risk of thromboischemic complications after percutaneous coronary intervention (PCI), particularly in type 2 diabetes. Little is known about the effects of glycemic control on platelet reactivity. We assessed adenosine diphosphate-induced platelet aggregation and flow cytometric expression of P-selectin in 90 patients (56 diabetic and 34 nondiabetic patients) undergoing coronary stent implantation after administration of clopidogrel as a potential predictor of poststent complications and its relation to glycemic control. Posttreatment platelet reactivity was significantly elevated in diabetic compared with nondiabetic participants and was associated with smoking, hypercholesterolemia, overweight, and cardiovascular ischemic events. A linear relationship was found between hemoglobin A1c in diabetic patients and platelet reactivity. Both methods (standard aggregometry and P-selectin expression) used for assessment of platelet function were positively correlated. Low responsiveness to clopidogrel detected by posttreatment platelet reactivity is a risk factor for ischemic events after PCI in diabetic patients.

Activation of hexosamine pathway impairs nitric oxide (NO)-dependent arteriolar dilations by increased protein O-GlcNAcylation

We hypothesized that under high glucose conditions, activation of the hexosamine pathway leads to impaired nitric oxide (NO)-dependent arteriolar dilation. Skeletal muscle arterioles (diameter: ~160μm) isolated from male Wistar rats were exposed to normal glucose (NG, 5.5mmol/L) or high glucose concentrations (HG, 30mmol/L, for 2h) and agonist-induced diameter changes were measured with videomicroscopy. Western blots were performed to identify the vascular levels of protein O-linked-N-acetyl-glucosamine (O-GlcNAc) and phosphorylated endothelial NO synthase (eNOS). In arterioles exposed to HG, dilations to histamine were abolished compared to those exposed to NG (max: -6±6% and 69±9%, respectively), while acetylcholine-induced responses were not affected. Inhibition of NO synthesis with N(G)-nitro-l-arginine methyl ester (L-NAME) reduced histamine-induced dilations in NG arterioles, but it had no effect on microvessels exposed to HG. Dilations to the NO donor, sodium nitroprusside and constrictions to norepinephrine and serotonin were similar in the two groups. In the presence of the inhibitor of hexosamine pathway, azaserine, histamine-induced dilations were significantly augmented in arterioles exposed to HG (max: 67±2%). Moreover, exposure of vessels to glucosamine (5mmol/L, for 2h) resulted in reduced histamine-induced arteriolar dilations (max: 26±3%). The level of protein O-GlcNAcylation was increased, whereas the P-eNOS (Ser-1177) was decreased in HG exposed vessels. These findings indicate that a high concentration of glucose may lead to glucosamine formation, which impairs histamine-induced, NO-mediated arteriolar dilations. We propose that interfering with the hexosamine pathway may prevent microvascular complications in diabetes.

Ultrasonography: Ariadne's Thread in the Diagnosis of the Cardiorenal Syndrome

The term cardiorenal syndrome (CRS) describes a broad spectrum of clinical conditions with four combinations of acute and chronic heart and kidney failure. Based on the pathophysiological primum movens, the actual classification recognizes five CRS types: in type I and II CRS, the initiating event is heart failure (acute or chronic), while it is kidney failure in type III and IV CRS; type V is linked to systemic diseases. Ultrasound techniques (echocardiography and ultrasonography of the kidney, inferior vena cava and chest) can be extremely helpful in establishing a prompt diagnosis and a correct CRS classification. Basic echocardiography allows evaluation of ventricular diastolic and systolic functions, investigates pulmonary congestion and pericardial effusion, and describes volume overload. On the other hand, renal ultrasound helps clinicians to distinguish between acute and chronic renal failure, excludes urinary tract dilation or pathological bladder repletion, and provides crucial information regarding kidney volume or echogenicity. Applying basic knowledge of echocardiography and renal ultrasound, nephrologists may be in a better position for patient treatment and management, bearing in mind that doctors can properly use a stethoscope although not being a cardiologist.

Role of catheter ablation of ventricular tachycardia associated with structural heart disease

In patients with structural heart disease, ventricular tachycardia (VT) worsens the clinical condition and may severely affect the short- and long-term prognosis. Several therapeutic options can be considered for the management of this arrhythmia. Among others, catheter ablation, a closed-chest therapy, can prevent arrhythmia recurrences by abolishing the arrhythmogenic substrate. Over the last two decades, different techniques have been developed for an effective approach to both tolerated and untolerated VTs. The clinical outcome of patients undergoing ablation has been evaluated in multiple studies. This editorial gives an overview of the role, methodology, clinical outcome and innovative approaches in catheter ablation of VT.

Physiology of potassium channels in the inner membrane of mitochondria

The inner membrane of the ATP-producing organelles of endosymbiotic origin, mitochondria, has long been considered to be poorly permeable to cations and anions, since the strict control of inner mitochondrial membrane permeability is crucial for efficient ATP synthesis. Over the past 30 years, however, it has become clear that various ion channels--along with antiporters and uniporters--are present in the mitochondrial inner membrane, although at rather low abundance. These channels are important for energy supply, and some are a decisive factor in determining whether a cell lives or dies. Their electrophysiological and pharmacological characterisations have contributed importantly to the ongoing elucidation of their pathophysiological roles. This review gives an overview of recent advances in our understanding of the functions of the mitochondrial potassium channels identified so far. Open issues concerning the possible molecular entities giving rise to the observed activities and channel protein targeting to mitochondria are also discussed.

Diabetes and alpha lipoic Acid

Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complications. Lipoic acid quenches reactive oxygen species, chelates metal ions, and reduces the oxidized forms of other antioxidants such as vitamin C, vitamin E, and glutathione. It also boosts antioxidant defense system through Nrf-2-mediated antioxidant gene expression and by modulation of peroxisome proliferator activated receptors-regulated genes. ALA inhibits nuclear factor kappa B and activates AMPK in skeletal muscles, which in turn have a plethora of metabolic consequences. These diverse actions suggest that lipoic acid acts by multiple mechanisms, many of which have only been uncovered recently. In this review we briefly summarize the known biochemical properties of lipoic acid and then discussed the oxidative mechanisms implicated in diabetic complications and the mechanisms by which lipoic acid may ameliorate these reactions. The findings of some of the clinical trials in which lipoic acid administration has been tested in diabetic patients during the last 10 years are summarized. It appears that the clearest benefit of lipoic acid supplementation is in patients with diabetic neuropathy.

Dendritic cells and damage-associated molecular patterns: endogenous danger signals linking innate and adaptive immunity

Dendritic cells (DCs) are potent antigen-presenting cells critical in regulating the adaptive immune response. The role of DCs is dichotomous; they may both present antigens and the appropriate stimulatory molecules to initiate an adaptive immune response, or they may induce tolerance and release anti-inflammatory signals. The activation of immature DCs, required for the expression of the necessary costimulatory T cell molecules, is dependent on pattern recognition receptors. In addition to the pathogen-derived ligands of pattern recognition receptors, several damage-associated molecular patterns (DAMPs) have recently been shown to interact with DCs and dramatically affect their ultimate function. The complex interplay of DAMPs on DCs is clinically important, with implications for transplantation, tumor immunity, autoimmunity, chronic inflammation and other conditions of sterile inflammation such as ischemia reperfusion injury. In this review, we will focus on the role of DAMPs in DC function.

Pericarditis: pathophysiology, diagnosis, and management

Pericarditis, the most common disease of the pericardium, may be isolated or a manifestation of a systemic disease. The etiology of pericarditis is varied and includes infectious (especially viral and tuberculosis) and noninfectious causes (autoimmune and autoinflammatory diseases, pericardial injury syndromes, and cancer [especially lung cancer, breast cancer, and lymphomas]). Most cases remain idiopathic with a conventional diagnostic evaluation. A targeted etiologic search should be directed to the most common cause on the basis of the patient's clinical background, epidemiologic issues, specific presentations, and high-risk features associated with specific etiologies or complications (fever higher than 38°C, subacute onset, large pericardial effusion, cardiac tamponade, lack of response to NSAIDs). The management of pericardial diseases is largely empiric because of the relative lack of randomized trials. NSAIDs are the mainstay of empiric anti-inflammatory therapy, with the possible addition of colchicine to prevent recurrences.

[Current coagulation diagnostics in intensive care medicine]

In the preoperative setting, a standardized questionnaire on bleeding history cannot be replaced by the Quick test or activated partial thromboplastin time (APTT) measurement. Thrombelastometry provides rapid measurement of coagulation in the intra- and postoperative settings. Besides the Quick test and APTT, thrombelastometry provides information about clot firmness and clot stability. This allows goal-directed management in coagulopathy, which results in a reduction of transfusion of blood products. Furthermore, this can lead to not only an overall reduced length of stay in the hospital, but also in the intensive care unit, thus, contributing to a significant cost reduction.

Renal dysfunction in acute heart failure

During treatment of acute heart failure (AHF), worsening renal function is often complicated and results in a complex clinical course. Furthermore, renal dysfunction is a strong independent predictor of long-term adverse outcomes in patients with AHF. Traditionally, the predominant cause of renal dysfunction has been attributed to impairment of cardiac output and relative underfilling of arterial perfusion. Recently, emerging data have led to the importance of venous congestion and elevated intra-abdominal pressure rather than confining it to impaired forward cardiac output as the primary driver of renal impairment. Relief of congestion is a major objective of AHF treatment but therapy is still based on the administration of loop diuretics. The results of the recently performed controlled studies for the assessment of new treatments to overcome resistance to diuretic treatment to protect kidneys from untoward effects have been mostly neutral. Better treatment of congestion in heart failure remains a major problem.

Percutaneous treatment in acute coronary syndromes

Both ST-segment elevation myocardial infarction and non-ST-segment elevation acute coronary syndromes (ACS) are the result of an acute thrombotic lesion obstructing blood flow in the coronary vasculature. Percutaneous treatment has shown to improve clinical outcome in this clinical setting by resolving coronary obstruction with different devices directed to restore coronary blood flow. In comparison with balloon alone angioplasty, implantation of bare metal stents reduced the rate of restenosis and cardiac events, but high rates of restenosis remained, leading to further investigations to develop drug-eluting stents with different pharmacological coatings that reduced restenosis rates and clinical events. In this review, we discuss the current treatment of ACS, reviewing recent randomized clinical trials and advances in medical treatment, including new antiplatelet agents and recent guideline recommendations.

Hypoadiponectinemia: A Link between Visceral Obesity and Metabolic Syndrome

Metabolic syndrome (MetS) represents a combination of cardiometabolic risk factors, including visceral obesity, glucose intolerance or type 2 diabetes, elevated triglycerides, reduced HDL cholesterol, and hypertension. MetS is rapidly increasing in prevalence worldwide as a consequence of the “epidemic” obesity, with a considerable impact on the global incidence of cardiovascular disease and type 2 diabetes. At present, there is a growing interest on the role of visceral fat accumulation in the occurrence of MetS. In this review, the effects of adipocytokines and other proinflammatory factors produced by fat accumulation on the occurrence of the MetS have been also emphasized. Accordingly, the “hypoadiponectinemia” has been proposed as the most interesting new hypothesis to explain the pathophysiology of MetS.

High-mobility group box 1 release and redox regulation accompany regeneration and remodeling of skeletal muscle

High-mobility group box 1 (HMGB1), a damage-associated molecular pattern (DAMP) molecules, favors tissue regeneration via recruitment and activation of leukocytes and stem cells. Here we demonstrate, in a model of acute sterile muscle injury, that regeneration is accompanied by active reactive oxygen species (ROS) production counterbalanced and overcome by the generation of antioxidant moieties. Mitochondria are initially responsible for ROS formation. However, they undergo rapid disruption with almost complete disappearance. Twenty-four hours after injury, we observed a strong induction of MURF1 and atrogin-1 ubiquitin ligases, key signals in activation of the proteasome system and induction of muscle atrophy. At later time points, ROS generation is maintained by nonmitochondrial sources. The antioxidant response occurs in both regenerating fibers and leukocytes that express high levels of free thiols and antioxidant enzymes, such as superoxide dismutase 1 (SOD1) and thioredoxin. HMGB1, a protein thiol, weakly expressed in healthy muscles, increases during regeneration in parallel with the antioxidant response in both fibers and leukocytes. A reduced environment may be important to maintain HMGB1 bioactivity. Indeed, oxidation abrogates both muscle stem cell migration in response to HMGB1 and their ability to differentiate into myofibers in vitro. We propose that the early antioxidant response in regenerating muscle limits HMGB1 oxidation, thus allowing successful muscle regeneration.

Methods of cell purification: a critical juncture for laboratory research and translational science

Research in cell biology and the development of translational technologies are driven by competition, public expectations, and regulatory oversight, putting these fields at a critical juncture. Success in these fields is quickly becoming dependent on the ability of researchers to identify and isolate specific cell populations from heterogeneous mixtures accurately and efficiently. Many methods for cell purification have been developed, and each has advantages and disadvantages that must be considered in light of the intended application. Current cell separation strategies make use of surface proteins, genetic expression, and physics to isolate specific cells by phenotypic traits. Cell purification is also dependent on the cellular reagents available for use and the intended application, as these factors may preclude certain mechanisms used in the processes of labeling and sorting cells.

Antioxidant and anti-inflammatory effects of exercise in diabetic patients

Diabetes is a chronic metabolic disease which is characterized by absolute or relative deficiencies in insulin secretion and/or insulin action. The key roles of oxidative stress and inflammation in the progression of vascular complications of this disease are well recognized. Accumulating epidemiologic evidence confirms that physical inactivity is an independent risk factor for insulin resistance and type II diabetes. This paper briefly reviews the pathophysiological pathways associated with oxidative stress and inflammation in diabetes mellitus and then discusses the impact of exercise on these systems. In this regard, we discuss exercise induced activation of cellular antioxidant systems through “nuclear factor erythroid 2-related factor.” We also discuss anti-inflammatory myokines, which are produced and released by contracting muscle fibers. Antiapoptotic, anti-inflammatory and chaperon effects of exercise-induced heat shock proteins are also reviewed.

Serum adiponectin level is not only decreased in metabolic syndrome but also in borderline metabolic abnormalities

Objective:

Along with the increasing prevalence of obesity and related diseases, particularly atherosclerotic diseases, metabolic syndrome (MetS) is now a common and major public health issue in many countries around the world. Adiponectin, a protein secreted by the adipose tissue, has become recognized as a key player in the development of MetS. These days, not only MetS but also borderline metabolic/physiological abnormalities, such as impaired fasting glucose, high normal blood pressure and high normal plasma cholesterol, have been reported to be risk factors for atherosclerotic disease. Therefore, we undertook this study to determine the relationship between adiponectin and borderline metabolic/physiological abnormalities, as well as MetS.

Design:

A cross-sectional study performed from April 2007 to November 2009.

Subjects:

In 16 892 Japanese adults (10 008 men and 6884 women), we examined the relationship between the serum adiponectin concentration and borderline metabolic/physiological abnormalities or MetS by a questionnaire survey about medical treatment, body size measurement and measurement of laboratory parameters including the serum adiponectin concentration.

Results:

Adiponectin showed a significant negative correlation with the number of MetS components. In subjects without overt diabetes mellitus, hypertension or dyslipidemia, the adiponectin concentration also showed a significant negative correlation with the number of borderline metabolic abnormalities.

Conclusion:

The decrease of circulating adiponectin may start before the development of diabetes mellitus, hypertension, dyslipidemia or MetS. Adiponectin is an important biomarker for reflecting the adverse influence of visceral fat in persons with MetS, and also in these subclinical states.

Betulinic acid ameliorates endothelium-dependent relaxation in L-NAME-induced hypertensive rats by reducing oxidative stress

Zizyphi Spinosi semen (ZSS) is one of the most widely used traditional Chinese herbs with protective effects on the cardiovascular system. It is not clear whether betulinic acid (BA), the key active constituent of ZSS, has beneficial cardiovascular effects on N(ω)-nitro-L-arginine methyl ester hydrochloride (L-NAME)-induced hypertensive rats. The objective of this study was to investigate the effect of BA on endothelium-dependent vasorelaxation in isolated aortic rings from L-NAME-induced hypertensive rats and its underlying mechanisms. Male Sprague-Dawley rats were injected with L-NAME (15 mg/kg/d, i.p.) for 4 weeks to induce hypertension. After treatment with L-NAME for 2 weeks, rats with mean blood pressure >120 mm Hg measured by tail-cuff method were considered hypertensive and then injected with BA (0.8, 4, 20 mg/kg/d, i.p.) for the last 2 weeks. The effect of BA on the tension of rat thoracic aortic rings was measured in an organ bath system. The levels of nitric oxide (NO), reactive oxygen species (ROS), and the activity of superoxide dismutase (SOD) and nitric oxide synthase (NOS) in aortas were assayed. We found that BA (0.1-100 μM) evoked a concentration-dependent vasorelaxation in endothelium-intact normal rat aortic rings, which was significantly attenuated by pretreatment with L-NAME (100 μM) or methylene blue (MB, 10 μM), but not by indomethacin (10 μM). Pretreatment with EC(50) (1.67 μM) concentration of BA enhanced the acetylcholine (ACh)-induced vasorelaxation, which was also markedly reversed by both L-NAME and MB. The blood pressure in hypertensive rats increased to 135.22±5.38 mm Hg (P<0.01 vs. control group), which was markedly attenuated by high dose of BA. The ACh-induced vasorelaxation in hypertensive rat aortic rings was impaired, which was markedly improved by chronic treatment with BA (20 mg/kg/d) for 2 weeks. The increase of ROS level and the decrease of NO level, SOD and eNOS activities in hypertensive rat aortas were all markedly inhibited by BA. These results indicate that BA decreased blood pressure and improved ACh-induced endothelium-dependent vasorelaxation in L-NAME-induced hypertension rats, which may be mediated by reducing oxidative stress and retaining the bioavailability of NO in the cardiovascular system.

Exercise Training Prevents Coronary Endothelial Dysfunction in Type 2 Diabetic Mice

Type 2 diabetes (T2D) is a leading risk factor for cardiovascular diseases including atherosclerosis and coronary heart disease. Exercise training (ET) is thought to have a beneficial effect on these disorders, but the basis for this effect is not fully understood. Because endothelial dysfunction plays a key role in the pathological events leading to cardiovascular complications in T2D, we hypothesized that the effects of ET will be evidenced by improvements in coronary endothelial function. To test this hypothesis, we assessed the effects of ET on vascular function of diabetic (db/db, Lepr(db)) mice by evaluating endothelial function of isolated coronary arterioles of wild-type (WT) and db/db mice with/without ET. Although dilation of vessels to the endothelial-independent vasodilator, sodium nitroprusside was not different between db/db and WT, dilation to the endothelial-dependent agonist, acetylcholine (ACh), was impaired in db/db compared to WT mice. Vasodilation to ACh was restored in db/db with ET and insulin sensitivity was improved in the db/db after ET. Exercise did not change body weight of db/db, but superoxide dismutase (SOD1 and SOD2) and phosphorylated- eNOS protein (Ser1177) expression in heart tissue was up-regulated whereas tumor necrosis factor-alpha (TNF-α) protein level was decreased by ET. Serum level of interleukin-6 (IL-6) was higher in db/db mice but ET decreased IL-6. This suggests that ET may improve endothelial function by increasing nitric oxide bioavailability as well as decreasing chronic inflammation. We suggest this connection may be the basis for the benefit of ET in T2D.