Rapid shedding of proinflammatory microparticles by human mononuclear cells exposed to cigarette smoke is dependent on Ca2+ mobilization

OBJECTIVES

Microparticles are membrane vesicles shed by cells upon activation and apoptosis. Agonists capable of inducing microparticle generation include cytokines, bacterial products, P-selectin, histamine. Cigarette smoke extract has also been recognized as an agonist involved in microparticle generation with an apoptosis-dependent mechanism. We investigated the possibility that cigarette smoke extract induces the rapid generation of proinflammatory microparticles by human mononuclear cells with a calcium-dependent mechanism.

MATERIALS AND METHODS

Human mononuclear cells were exposed to cigarette smoke extract. [Ca(2+)]i mobilization was assessed with the fluorescent probe Fluo-4 NW. Microparticles were quantified with a prothrombinase assay and by flow cytometry. Normal human bronchial epithelial cells and A549 alveolar cells were incubated with cigarette smoke extract-induced microparticles and the generation of ICAM-1, IL-8, and MCP-1 was assessed by ELISA.

RESULTS

Exposure to cigarette smoke extract induced a rapid increase in [Ca(2+)]i mobilization. Microparticle generation was also increased. EGTA, verapamil and the calmodulin inhibitor, W-7, inhibited microparticle generation. Incubation of lung epithelial cells with cigarette smoke extract-induced microparticles increased the expression of proinflammatory mediators.

CONCLUSIONS

Exposure of mononuclear cells to cigarette smoke extract causes a rapid shedding of microparticles with a proinflammatory potential that might add to the mechanisms of disease from tobacco use.

Crystallin αB acts as a molecular guard in mouse decidualization: regulation and function during early pregnancy

Although decidualization is crucial for the establishment of successful pregnancy, the molecular mechanism underlying decidualization remains poorly understood. Crystallin αB (CryAB), a small heat shock protein (sHSP), is up-regulated and phosphorylated in mouse decidua. In mouse primary endometrial stromal cells, CryAB is induced upon progesterone treatment via HIF1α. In addition, CryAB is strongly phosphorylated through the p38-MAPK pathway under stress or during in vitro decidualization. Knockdown of CryAB results in the increase of apoptosis of stromal cells and inhibits decidualization under oxidative or inflammatory stress. Our data indicate that CryAB protects decidualization against stress conditions.

Bone marrow mesenchymal stem cell transplantation for improving nerve regeneration

Although the peripheral nervous system has an inherent capacity for regeneration, injuries to nerves still result in considerable disabilities. The persistence of these disabilities along with the underlying problem of nerve reconstruction has motivated neuroscientists worldwide to seek additional therapeutic strategies. In recent years, cell-based therapy has emerged as a promising therapeutic tool. Schwann cells (SCs) are the main supportive cells for peripheral nerve regeneration; however, there are several technical limitations regarding its application for cell-based therapy. In this context, bone marrow mesenchymal stem cells (BM-MSCs) have been used as alternatives to SCs for treating peripheral neuropathies, showing great promise. Several studies have been trying to shed light on the mechanisms behind the nerve regeneration-promotion potential of BM-MSCs. Although not completely clarified, understanding how BM-MSCs exert tissue repair effects will facilitate their development as therapeutic agents before they become a clinically viable tool for encouraging peripheral nerve regeneration.

Cigarette smoke adversely affects functions and cell membrane integrity in c-kit+ cardiac stem cells

Cigarette smoking is a major risk factor for numerous diseases including cardiovascular diseases. Exposure to cigarette smoke (CS) leads to increased cardiovascular risk, myocardial injury, and mortality. Stem cell therapy is one of the promising therapeutic options available to treat myocardial injuries. Understanding the impact of cigarette smoke extract (CSE) on stem cell function would be valuable in determining the risk passed on during transplant. In this study, the impact of CSE on cardiac stem cell (CSC) functions was investigated using c-kit+ rat cardiac stem cells as the experimental model. Here, we hypothesized that CSE attenuates CSC membrane integrity, causes cytotoxicity, and affects many CSC functions via multiple mechanisms including modulation of extracellular stress-regulated kinase (ERK) (44/42) signaling and oxidative stress. The effects of CSE on CSCs were examined in vitro. Based on a published method, CSE was prepared. CSE-induced ERK signaling was detected by western blotting. CSE-induced modulation of catalase activity was also measured. Functional modulations due to CSE were examined via several methods including Apostain, BrdU, and LDH assays. In agreement with the CSE-induced activation of ERK, CSE-induced reduction in viability, migration, and increase in both cytotoxicity and para-cellular permeability were observed in CSCs. These results suggest that CSE impaired CSC responses that contribute to decreased ability of CSC to respond to stress or injury leading to exacerbation of the damage. Our findings will contribute to the understanding of the discipline and might contribute to the development of stem cell therapy approaches in the future.

Na+ dysregulation coupled with Ca2+ entry through NCX1 promotes muscular dystrophy in mice

Unregulated Ca(2+) entry is thought to underlie muscular dystrophy. Here, we generated skeletal-muscle-specific transgenic (TG) mice expressing the Na(+)-Ca(2+) exchanger 1 (NCX1) to model its identified augmentation during muscular dystrophy. The NCX1 transgene induced dystrophy-like disease in all hind-limb musculature, as well as exacerbated the muscle disease phenotypes in δ-sarcoglycan (Sgcd(-/-)), Dysf(-/-), and mdx mouse models of muscular dystrophy. Antithetically, muscle-specific deletion of the Slc8a1 (NCX1) gene diminished hind-limb pathology in Sgcd(-/-) mice. Measured increases in baseline Na(+) and Ca(2+) in dystrophic muscle fibers of the hind-limb musculature predicts a net Ca(2+) influx state due to reverse-mode operation of NCX1, which mediates disease. However, the opposite effect is observed in the diaphragm, where NCX1 overexpression mildly protects from dystrophic disease through a predicted enhancement in forward-mode NCX1 operation that reduces Ca(2+) levels. Indeed, Atp1a2(+/-) (encoding Na(+)-K(+) ATPase α2) mice, which have reduced Na(+) clearance rates that would favor NCX1 reverse-mode operation, showed exacerbated disease in the hind limbs of NCX1 TG mice, similar to treatment with the Na(+)-K(+) ATPase inhibitor digoxin. Treatment of Sgcd(-/-) mice with ranolazine, a broadly acting Na(+) channel inhibitor that should increase NCX1 forward-mode operation, reduced muscular pathology.

Preconditioning of mesenchymal stem cells by sevoflurane to improve their therapeutic potential

Background

Bone marrow mesenchymal stem cells (MSCs) have been found to produce beneficial effects on ischemia-reperfusion injury. However, most of the MSCs died when transplanted into the ischemic tissue, which severely limit their therapeutic potential.

Methods

Using an in vitro model of hypoxia and serum deprivation (H/SD), we investigated the hypothesis that sevoflurane preconditioning could protect MSCs against H/SD-induced apoptosis and improve their migration, proliferation, and therapeutic potential. The H/SD of MSCs and neuron-like PC12 cells were incubated in a serum-free medium and an oxygen concentration below 0.1% for 24 h. Sevoflurane preconditioning was performed through a 2-h incubation of MSCs in an airtight chamber filled with 2 vol% sevoflurane. Apoptosis of MSCs or neuron-like PC12 cells was assessed using Annexin V-FITC/propidium iodide (PI). Furthermore, the mitochondrial membrane potential was assessed using lipophilic cationic probe. The proliferation rate was evaluated through cell cycle analysis. Finally, HIF-1α, HIF-2α, VEGF and p-Akt/Akt levels were measured by western blot.

Results

Sevoflurane preconditioning minimized the MSCs apoptosis and loss of mitochondrial membrane potential. Furthermore, it increased the migration and expression of HIF-1α, HIF-2α, VEGF, and p-Akt/Akt, reduced by H/SD. In addition, neuron-like PC12 cells were more resistant to H/SD-induced apoptosis when they were co-cultured with sevoflurane preconditioning MSCs.

Conclusion

These findings suggest that sevoflurane preconditioning produces protective effects on survival and migration of MSCs against H/SD, as well as improving the therapeutic potential of MSCs. These beneficial effects might be mediated at least in part by upregulating HIF-1α, HIF-2α, VEGF, and p-Akt/Akt.

Cell biological roles of αB-crystallin

αB-crystallin, also called HspB5, is a molecular chaperone able to interact with unfolding proteins. By interacting, it inhibits further unfolding, thereby preventing protein aggregation and allowing ATP-dependent chaperones to refold the proteins. αB-crystallin belongs to the family of small heat-shock proteins (sHsps), which in humans consists of 10 different members. The protein forms large oligomeric complexes, containing up to 40 or more subunits, which in vivo consist of heterooligomeric complexes formed by a mixture of αB-crystallin and other sHsps. αB-crystallin is highly expressed in the lens and to a lesser extent in several other tissues, among which heart, skeletal muscle and brain. αB-crystallin plays a role in several cellular processes, such as signal transduction, protein degradation, stabilization of cytoskeletal structures and apoptosis. Mutations in the αB-crystallin gene can have detrimental effects, leading to pathologies such as cataract and cardiomyopathy. This review describes the biological roles of αB-crystallin, with a special focus on its function in the eye lens, heart muscle and brain. In addition its therapeutic potential is discussed.

Contribution of small heat shock proteins to muscle development and function

Investigations undertaken over the past years have led scientists to introduce the concept of protein quality control (PQC) systems, which are responsible for polypeptide processing. The PQC system monitors proteostasis and involves activity of different chaperones such as small heat shock proteins (sHSPs). These proteins act during normal conditions as housekeeping proteins regulating cellular processes, and during stress conditions. They also mediate the removal of toxic misfolded polypeptides and thereby prevent development of pathogenic states. It is postulated that sHSPs are involved in muscle development. They could act via modulation of myogenesis or by maintenance of the structural integrity of signaling complexes. Moreover, mutations in genes coding for sHSPs lead to pathological states affecting muscular tissue functioning. This review focuses on the question how sHSPs, still relatively poorly understood proteins, contribute to the development and function of three types of muscle tissue: skeletal, cardiac and smooth.

EPO-dependent activation of PI3K/Akt/FoxO3a signalling mediates neuroprotection in in vitro and in vivo models of Parkinson's disease

Erythropoietin (EPO) may become a potential therapeutic candidate for the treatment of the neurodegenerative disorder -- Parkinson's disease (PD), since EPO has been found to prevent neuron apoptosis through the activation of cell survival signalling. However, the underlying mechanisms of how EPO exerts its neuroprotective effect are not fully elucidated. Here we investigated the mechanism by which EPO suppressed 6-hydroxydopamine (6-OHDA)-induced neuron death in in vitro and in vivo models of PD. EPO knockdown conferred 6-OHDA-induced cytotoxicity. This effect was reversed by EPO administration. Treatment of PC12 cells with EPO greatly diminished the toxicity induced by 6-OHDA in a dose- and time-dependent manner. EPO effectively reduced apoptosis of striatal neurons and induced a significant improvement on the neurological function score in the rat models of PD. Furthermore, EPO increased the expression of phosphorylated Akt and phosphorylated FoxO3a, and abrogated the 6-OHDA-induced dysregulation of Bcl-2, Bax and Caspase-3 in PC12 cells and in striatal neurons. Meanwhile, the EPO-dependent neuroprotection was notably reversed by pretreatment with LY294002, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K). Our data suggest that PI3K/Akt/FoxO3a signalling pathway may be a possible mechanism involved in the neuroprotective effect of EPO in PD.

Experimental study on the effect of intravenous stem cell therapy on intestinal ischemia reperfusion induced myocardial injury

BACKGROUND AND OBJECTIVES

The myocyte death that follows intestinal ischemia reperfusion (I/R) injury is a major factor contributing to high mortality and morbidity in ischemic heart disease. The purpose of stem cell (SC) therapy for myocardial infarction is to improve clinical outcomes. The present study aimed at investigating the possible therapeutic effect of intravenous human cord blood mesenchymal stem cells (HCBMSCs) on intestinal ischemia reperfusion induced cardiac muscle injury in albino rat.

METHODS AND RESULTS

Thirty male albino rats were divided equally into control (Sham-operated) group, I/R group where rats were exposed to superior mesenteric artery ligation for 1 hour followed by 1 hour reperfusion. In SC therapy group, the rats were injected with HCBMSCs into the tail vein. The rats were sacrificed four weeks following therapy. Cardiac muscle sections were exposed to histological, histochemical, immunohistochemical and morphometric studies. In I/R group, multiple fibers exhibited deeply acidophilic sarcoplasm with lost striations and multiple fibroblasts appeared among the muscle fibers. In SC therapy group, few fibers appeared with deeply acidophilic sarcoplasm and lost striations. Mean area of muscle fibers with deeply acidophilic sarcoplasm and mean area% of fibroblasts were significantly decreased compared to I/R group. Prussion blue and CD105 positive cells were found in SC therapy group among the muscle fibers, inside and near blood vessels.

CONCLUSIONS

Intestinal I/R induced cardiac muscle degenerative changes. These changes were ameliorated following HCBMSC therapy. A reciprocal relation was recorded between the extent of regeneration and the existence of undifferentiated mesenchymal stem cells.

The role of late I Na in development of cardiac arrhythmias

Late I Na is an integral part of the sodium current, which persists long after the fast-inactivating component. The magnitude of the late I Na is relatively small in all species and in all types of cardiomyocytes as compared with the amplitude of the fast sodium current, but it contributes significantly to the shape and duration of the action potential. This late component had been shown to increase in several acquired or congenital conditions, including hypoxia, oxidative stress, and heart failure, or due to mutations in SCN5A, which encodes the α-subunit of the sodium channel, as well as in channel-interacting proteins, including multiple β subunits and anchoring proteins. Patients with enhanced late I Na exhibit the type-3 long QT syndrome (LQT3) characterized by high propensity for the life-threatening ventricular arrhythmias, such as Torsade de Pointes (TdP), as well as for atrial fibrillation. There are several distinct mechanisms of arrhythmogenesis due to abnormal late I Na, including abnormal automaticity, early and delayed after depolarization-induced triggered activity, and dramatic increase of ventricular dispersion of repolarization. Many local anesthetic and antiarrhythmic agents have a higher potency to block late I Na as compared with fast I Na. Several novel compounds, including ranolazine, GS-458967, and F15845, appear to be the most selective inhibitors of cardiac late I Na reported to date. Selective inhibition of late I Na is expected to be an effective strategy for correcting these acquired and congenital channelopathies.

(-)-Epigallocatechin-gallate (EGCG) stabilize the mitochondrial enzymes and inhibits the apoptosis in cigarette smoke-induced myocardial dysfunction in rats

The present study brings out the preventive role of (-)-epigallocatechin-gallate (EGCG) on cardiac mitochondrial metabolism and apoptosis in cigarette smoke (CS)-exposed rats. The CS-exposed rats showed significantly decreased activities of TCA cycle enzymes and mitochondrial enzymatic antioxidants, on the other hand, mitochondrial lipid peroxidation was increased and GSH level was decreased. Further, CS exposure was found to induce cardiac apoptosis through release of cytochrome c into the cytosol, cleavage of pro-caspase-3 to active caspase-3, up-regulation of pro-apoptotic (Bax) and down-regulation of antiapoptotic (Bcl-2) molecules. The CS-induced apoptosis was further confirmed by mitochondrial and nuclear ultra structural apoptotic features as evaluated by electron microscopic studies. EGCG supplementation shelters the activities of TCA cycle enzymes and antioxidant enzymes, with concomitant decrease in lipid peroxidation and increase in GSH level. EGCG administration inhibited apoptosis through the inhibition of cytochrome c release into cytosol, activation of pro-caspase-3, down regulation of Bax and significant up regulation of Bcl-2. EGCG reversed the ultra structural apoptotic alterations of mitochondria and nucleus. The present study has provided experimental evidences that the EGCG treatment enduring to cardio protection at mitochondrial level.

Comparison of the cytotoxic potential of cigarette smoke and electronic cigarette vapour extract on cultured myocardial cells

BACKGROUND

Electronic cigarettes (ECs) have been marketed as an alternative-to-smoking habit. Besides chemical studies of the content of EC liquids or vapour, little research has been conducted on their in vitro effects. Smoking is an important risk factor for cardiovascular disease and cigarette smoke (CS) has well-established cytotoxic effects on myocardial cells. The purpose of this study was to evaluate the cytotoxic potential of the vapour of 20 EC liquid samples and a "base" liquid sample (50% glycerol and 50% propylene glycol, with no nicotine or flavourings) on cultured myocardial cells. Included were 4 samples produced by using cured tobacco leaves in order to extract the tobacco flavour.

METHODS

Cytotoxicity was tested according to the ISO 10993-5 standard. By activating an EC device at 3.7 volts (6.2 watts-all samples, including the "base" liquid) and at 4.5 volts (9.2 watts-four randomly selected samples), 200 mg of liquid evaporated and was extracted in 20 mL of culture medium. Cigarette smoke (CS) extract from three tobacco cigarettes was produced according to ISO 3308 method (2 s puffs of 35 mL volume, one puff every 60 s). The extracts, undiluted (100%) and in four dilutions (50%, 25%, 12.5%, and 6.25%), were applied to myocardial cells (H9c2); percent-viability was measured after 24 h incubation. According to ISO 10993-5, viability of <70% was considered cytotoxic.

RESULTS

CS extract was cytotoxic at extract concentrations >6.25% (viability: 76.9 ± 2.0% at 6.25%, 38.2 ± 0.5% at 12.5%, 3.1 ± 0.2% at 25%, 5.2 ± 0.8% at 50%, and 3.9 ± 0.2% at 100% extract concentration). Three EC extracts (produced by tobacco leaves) were cytotoxic at 100% and 50% extract concentrations (viability range: 2.2%-39.1% and 7.4%-66.9% respectively) and one ("Cinnamon-Cookies" flavour) was cytotoxic at 100% concentration only (viability: 64.8 ± 2.5%). Inhibitory concentration 50 was >3 times lower in CS extract compared to the worst-performing EC vapour extract. For EC extracts produced by high-voltage and energy, viability was reduced but no sample was cytotoxic according to ISO 10993-5 definition. Vapour produced by the "base" liquid was not cytotoxic at any extract concentration. Cell survival was not associated with nicotine concentration of EC liquids.

CONCLUSIONS

This study indicates that some EC samples have cytotoxic properties on cultured cardiomyoblasts, associated with the production process and materials used in flavourings. However, all EC vapour extracts were significantly less cytotoxic compared to CS extract.

Paracrine potential of fibroblasts exposed to cigarette smoke extract with vascular growth factor induction

OBJECTIVES/HYPOTHESIS

Nicotine, a major constituent of cigarette smoke, can activate the cholinergic anti-inflammatory pathway by binding to α7-nicotinic acetylcholine receptor (α7nAChR) expressed on the surface of certain cells. Here, we ask whether cigarette smoke extract induced different paracrine factors compared to the in vivo regulator of inflammation, tumor necrosis factor-α, in human vocal fold fibroblasts (hVFFs) shown to express low levels of α7nAChR.

STUDY DESIGN

In vitro.

METHODS

α7nAChR was detected by nested polymerase chain reaction and immunohistochemistry. γH2AX, a marker for DNA double-stand breaks, was measured by immunofluorescence. Cigarette smoke extract was prepared in accordance with investigators studying effects of cigarette smoke. hVFFs treated for 3 hours had media replaced for an additional 24 hours. Cytokine, chemokine, and growth factor levels in media were assessed by multiplex analysis.

RESULTS

α7nAChR expression levels decreased with the passage number of fibroblasts. Tumor necrosis factor-α induced a significantly different profile of cytokines, chemokines, and growth factor compared to cigarette smoke extract exposure. Cigarette smoke extract at a concentration not associated with induction of γH2AX nuclear foci significantly increased vascular endothelial growth factor.

CONCLUSIONS

Cigarette smoke extract elicited a response important for regulation of angiogenesis and vascular permeability during inflammation, without evidence of DNA double-stand breaks associated with carcinogenesis. hVFFs are capable of participating in paracrine regulation of pathological blood vessel formation associated with cigarette smoking-related diseases (ie, Reinke edema). These cells express α7nAChR, an essential component of the cholinergic anti-inflammatory pathway regulated by the vagus nerve in certain tissues and a target of therapeutic agents.

Cardiomyocyte-specific p65 NF-κB deletion protects the injured heart by preservation of calcium handling

NF-κB is a well-known transcription factor that is intimately involved with inflammation and immunity. We have previously shown that NF-κB promotes inflammatory events and mediates adverse cardiac remodeling following ischemia reperfusion (I/R). Conversely, others have pointed to the beneficial influence of NF-κB in I/R injury related to its anti-apoptotic effects. Understanding the seemingly disparate influence of manipulating NF-κB is hindered, in part, by current approaches that only indirectly interfere with the function of its most transcriptionally active unit, p65 NF-κB. Mice were generated with cardiomyocyte-specific deletion of p65 NF-κB. Phenotypically, these mice and their hearts appeared normal. Basal and stimulated p65 expression were significantly reduced in whole hearts and completely ablated in isolated cardiomyocytes. When compared with wild-type mice, transgenic animals were protected from both global I/R by Langendorff as well as regional I/R by coronary ligation and release. The protected, transgenic hearts had less cytokine activity and decreased apoptosis. Furthermore, p65 ablation was associated with enhanced calcium reuptake by the sarcoplasmic reticulum. This influence on calcium handling was related to increased expression of phosphorylated phospholamban in conditional p65 null mice. In conclusion, cardiomyocyte-specific deletion of the most active, canonical NF-κB subunit affords cardioprotection to both global and regional I/R injury. The beneficial effects of NF-κB inhibition are related, in part, to modulation of intracellular calcium homeostasis.

The potential role of small heat shock proteins in mitochondria

Mitochondria play a central role in cellular metabolism, calcium homeostasis, redox signaling and cell fates. Mitochondrial homeostasis is tightly regulated, and mitochondrial dysfunction is frequently associated with severe human pathologies. Small heat shock proteins are molecular chaperones that play major roles in development, stress responses, and diseases, and have been envisioned as targets for therapy. The mechanisms that lie behind the cytoprotection of small heat shock proteins are related to the regulation of mitochondrial functions. This review recapitulates the current knowledge of the expression of various small heat shock proteins in mitochondria and discusses their implication in the role of mitochondria and their regulation. Based on their involvement in mitochondrial normal physiology and pathology, a better understanding of their roles and regulation will pave the way for innovative approaches for the successful treatment of a range of stress-related syndromes whose etiology is based upon dysfunction of mitochondria.

Late sodium current inhibition in acquired and inherited ventricular (dys)function and arrhythmias

The late sodium current has been increasingly recognized for its mechanistic role in various cardiovascular pathologies, including angina pectoris, myocardial ischemia, atrial fibrillation, heart failure and congenital long QT syndrome. Although relatively small in magnitude, the late sodium current (I(NaL)) represents a functionally relevant contributor to cardiomyocyte (electro)physiology. Many aspects of I(NaL) itself are as yet still unresolved, including its distribution and function in different cell types throughout the heart, and its regulation by sodium channel accessory proteins and intracellular signalling pathways. Its complexity is further increased by a close interrelationship with the peak sodium current and other ion currents, hindering the development of inhibitors with selective and specific properties. Thus, increased knowledge of the intricacies of the complex nature of I(NaL) during distinct cardiovascular conditions and its potential as a pharmacological target is essential. Here, we provide an overview of the functional and electrophysiological effects of late sodium current inhibition on the level of the ventricular myocyte, and its potential cardioprotective and anti-arrhythmic efficacy in the setting of acquired and inherited ventricular dysfunction and arrhythmias.

Endothelin-1 release during the early phase of reperfusion is a mediator of myocardial reperfusion injury

PURPOSE

In acute myocardial infarction, left ventricular (LV) unloading reduces endothelin-1 (ET-1) release. We tested that endogenous ET-1 released during acute myocardial infarction might mediate ischemia/reperfusion (I/R) injury by stimulating increased intracellular calcium concentration, [Ca(2+)]i, and apoptosis.

METHODS

Rabbits were subjected to 1 h of coronary artery occlusion followed by 3 h of reperfusion. Unloading was initiated 15 min prior to reperfusion and was maintained during reperfusion. The control group was subjected to reperfusion. Animals were treated with ET-1 receptor antagonist BQ123. In parallel, isolated rabbit cardiomyocytes subjected to simulated I/R with or without ET-1 or BQ123, intracellular Ca(2+) and cell death were assessed with flow cytometry.

RESULTS

LV unloading prior to reperfusion reduced myocardial ET-1 release at 2 h of reperfusion. Infarct size was reduced in unloaded and BQ123 groups versus controls. LV unloading and BQ123 treatment reduced the percentage of apoptotic cells associated with increases in Bcl-2 protein levels in ischemic regions. BQ123 reduced both ET-1-induced [Ca(2+)]i increase and cell death for myocytes subjected to stimulated I/R.

CONCLUSION

We propose that components of reperfusion injury involve ET-1 release which stimulates calcium overload and apoptosis. Intravenous ET-1 receptor blockade prior to reperfusion may be a protective adjunct to reperfusion therapy in acute myocardial infarction patients.

The Revised Cardiac Risk Index in the new millennium: a single-centre prospective cohort re-evaluation of the original variables in 9,519 consecutive elective surgical patients

PURPOSE

Cardiac complications following non-cardiac surgery are major causes of morbidity and mortality. The Revised Cardiac Risk Index (RCRI) has become a standard for predicting post-surgical cardiac complications. This study re-examined the original six risk factors to confirm their validity in a large modern prospective database.

METHODS

Using the definitions in the original risk index, this study included 9,519 patients aged ≥ 50 undergoing elective non-cardiac surgery with an expected length of stay ≥ two days at two major tertiary-care teaching hospitals. The validity of the original predictors was tested in this population using binomial logistic regression modelling, area under the receiver operator curve (ROC) analysis, and the net reclassification index.

RESULTS

Rates of major cardiac complications with 0, 1, 2, ≥ 3 of the predictors were 0.5%, 2.6%, 7.2%, and 14.4%, respectively, in our patient cohort compared with 0.4%, 1.1%, 4.6%, and 9.7%, respectively, in the original cohort. Similar to the original report, binary logistic regression analysis showed that both preoperative treatment with insulin (odds ratio [OR] 1.4; 95% confidence interval [CI] 0.7 to 2.6) and preoperative creatinine > 176.8 mmol·L(-1) (OR 1.7; 95% CI 0.8 to 3.6) did not improve the predictive ability of the index. Analysis of the remaining four factors resulted in an area under the curve (AUC) identical to that seen for the reconstructed six-factor RCRI (AUC = 0.79). We found that a glomerular filtration rate (GFR) < 30 mL·min(-1) was a better predictor of major cardiac complications (OR 2.2; 95% CI 1.2 to 4.3) than creatinine > 176.8 mmol·L(-1). The receiver operating characteristic analysis of this resultant 5-Factor model resulted in an AUC of 0.79, with 0, 1, 2, ≥ 3 of the predictors representing 0.5%, 2.9%, 7.4%, and 17.0% risk, respectively, among our patient cohort.

CONCLUSION

Compared with the RCRI, a simplified 5-Factor model using a high-risk type of surgery, a history of ischemic heart disease, congestive heart failure, cerebrovascular disease, and a preoperative GFR < 30 mL·min(-1) results in superior prediction of major cardiac complications following elective non-cardiac surgery.

The arrhythmogenic consequences of increasing late INa in the cardiomyocyte

This review presents the roles of cardiac sodium channel NaV1.5 late current (late INa) in generation of arrhythmic activity. The assumption of the authors is that proper Na(+) channel function is necessary to the maintenance of the transmembrane electrochemical gradient of Na(+) and regulation of cardiac electrical activity. Myocyte Na(+) channels' openings during the brief action potential upstroke contribute to peak INa and initiate excitation-contraction coupling. Openings of Na(+) channels outside the upstroke contribute to late INa, a depolarizing current that persists throughout the action potential plateau. The small, physiological late INa does not appear to be critical for normal electrical or contractile function in the heart. Late INa does, however, reduce the net repolarizing current, prolongs action potential duration, and increases cellular Na(+) loading. An increase of late INa, due to acquired conditions (e.g. heart failure) or inherited Na(+) channelopathies, facilitates the formation of early and delayed afterpolarizations and triggered arrhythmias, spontaneous diastolic depolarization, and cellular Ca(2+) loading. These in turn increase the spatial and temporal dispersion of repolarization time and may lead to reentrant arrhythmias.

Na⁺ transport in the normal and failing heart - remember the balance

In the heart, intracellular Na(+) concentration ([Na(+)]i) is a key modulator of Ca(2+) cycling, contractility and cardiac myocyte metabolism. Several Na(+) transporters are electrogenic, thus they both contribute to shaping the cardiac action potential and at the same time are affected by it. [Na(+)]i is controlled by the balance between Na(+) influx through various pathways, including the Na(+)/Ca(2+) exchanger and Na(+) channels, and Na(+) extrusion via the Na(+)/K(+)-ATPase. [Na(+)]i is elevated in HF due to a combination of increased entry through Na(+) channels and/or Na(+)/H(+) exchanger and reduced activity of the Na(+)/K(+)-ATPase. Here we review the major Na(+) transport pathways in cardiac myocytes and how they participate in regulating [Na(+)]i in normal and failing hearts. This article is part of a Special Issue entitled "Na(+) Regulation in Cardiac Myocytes."

Protein carbonylation in human endothelial cells exposed to cigarette smoke extract

Cigarette smoke is a significant independent risk factor for vascular diseases and is a leading cause of structural and functional alterations of the vascular endothelium. In this study, we show protein carbonylation in the human umbilical vein endothelial cell line (ECV-304) exposed to whole-phase cigarette smoke extract. The main carbonylated proteins, including cytoskeletal proteins, glycolytic enzymes, xenobiotic metabolizing and antioxidant enzymes, and endoplasmic reticulum proteins, were identified by means of two-dimensional electrophoresis and Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) mass spectrometry (redox proteomics). Morphological analyses by fluorescence microscopy evidenced alterations in the microtubule cytoskeleton, especially at longer exposure time to cigarette smoke extract. Morphological analyses by transmission electron microscopy showed vacuolisation of the cytoplasm, alteration of mitochondria ultrastructure, and some enlargement of the perinuclear space. The possible role played by protein carbonylation caused by reactive species contained in cigarette smoke in the cigarette smoke-induced endothelial injury is discussed.

The Na+/Ca²+ exchanger in cardiac ischemia/reperfusion injury

The Na⁺/Ca²⁺ exchanger (NCX) is an important electrogenic transporter in maintaining Na⁺ and Ca²⁺ homeostasis in a variety of mammalian organs, and is involved in the physiological and pathophysiological regulation of Ca²⁺ concentration in the myocardium. It can affect cardial structure, electrophysiology and contractile properties. The role of the NCX in heart cells following ischemia/reperfusion (IR) has been investigated using a number of in vitro and in vivo models. During ischemia, ionic disturbances favor Ca²⁺-influx mode activity as excess Na⁺ is extruded in exchange for Ca²⁺, giving rise to increased intracellular Ca²⁺ levels (Cai). This rise in Cai contributes to reversible cellular dysfunction upon reperfusion, such as myocardial necrosis, arrhythmia, systolic dysfunction and heart failure. We have reviewed the major in vivo and in vitro cardiac IR-related NCX studies in an attempt to clarify the functions of NCX in IR and conclude that recent studies suggest blockage of NCX has potential therapeutic applications. Although the use of different IR models, application of NCX stimulators and inhibitors, and development of NCX transgenic animals do help elucidate the role of this ion exchanger in heart cells, related mechanisms are not completely understood and clinically effective specific NCX inhibitors need further research.

Reductive stress linked to small HSPs, G6PD, and Nrf2 pathways in heart disease

SIGNIFICANCE

Aerobic organisms must exist between the dueling biological metabolic processes for energy and respiration and the obligatory generation of reactive oxygen species (ROS) whose deleterious consequences can reduce survival. Wide fluctuations in harmful ROS generation are circumvented by endogenous countermeasures (i.e., enzymatic and nonenzymatic antioxidants systems) whose capacity decline with aging and are enhanced by disease states.

RECENT ADVANCES

Substantial efforts on the cellular and molecular underpinnings of oxidative stress has been complemented recently by the discovery that reductive stress similarly predisposes to inheritable cardiomyopathy, firmly establishing that the biological extremes of the redox spectrum play essential roles in disease pathogenesis.

CRITICAL ISSUES

Because antioxidants by nutritional or pharmacological supplement to prevent or mitigate disease states have been largely disappointing, we hypothesize that lack of efficacy of antioxidants might be related to adverse outcomes in responders at the reductive end of the redox spectrum. As emerging concepts, such as reductive, as opposed, oxidative stress are further explored, there is an urgent and critical gap for biochemical phenotyping to guide the targeted clinical applications of therapeutic interventions.

FUTURE DIRECTIONS

New approaches are vitally needed for characterizing redox states with the long-term goal to noninvasively assess distinct clinical states (e.g., presymptomatic, end-stage) with the diagnostic accuracy to guide personalized medicine.

The late Na current as a therapeutic target: where are we?

In this article we review the late Na current which functionally can be measured using patch-clamp electrophysiology (INa,late). This current is largely enhanced under pathological myocardial conditions such as ischemia and heart failure. In addition, INa,late can cause systolic and diastolic contractile dysfunction via a Na-dependent Ca-overload of the myocyte. Moreover, INa,late plays a crucial role as ventricular and atrial proarrhythmic substrate in myocardial pathology by changing cellular electrophysiology. We summarize recent experimental and clinical studies that investigate therapeutic inhibition of this current and discuss the significance of the available data and try to answer not only the question, where we currently are but also where we may go in the near future. This article is part of a Special Issue entitled "Na(+) Regulation in Cardiac Myocytes".

Signaling network of OSW‑1‑induced apoptosis and necroptosis in hepatocellular carcinoma

The compound 3β, 16β, 17α‑trihydroxycholest‑5‑en‑22‑one 16‑O‑(2‑O‑4‑methoxybenzoyl‑β‑D‑xylopyranosyl)‑ (1→3)‑(2‑O‑acetyl‑α‑L‑arabinopyranoside (OSW‑1) is a member of the cholestane saponin family that was created in the bulbs of Ornithogalum saudersiae. OSW‑1 has previously been shown as cytotoxic against numerous types of malignant cells, however, its antitumoral mechanisms remain unclear. The present study aimed to examine the potential changes in the gene expression of a hepatocellular carcinoma (HCC) cell line (Hep3B) incubated with OSW‑1 in vitro. The results showed that OSW‑1 inhibited tumors through invasiveness, angiogenesis, cell polarity and cell adhesion (as shown by Roche NimbleGen gene expression analysis), in addition to inducing apoptosis through the mitochondrial pathway. This affected the expression of a number of core genes in a number of signaling pathways, including WNT, MAPK, VEGF and P53. To the best of our knowledge, the present study is the first to report that OSW‑1, as a molecular compound, induces necroptotic death in hepatocellular carcinoma (HCC).

Applications of flow cytometry to toxicological mycotoxin effects in cultured mammalian cells: a review

This review gives an overview of flow cytometry applications to toxicological studies of several physiological target sites of mycotoxins on different mammalian cell lines. Mycotoxins are secondary metabolites of fungi that may be present in food, feed, air and water. The increasing presence of mycotoxins in crops, their wide distribution in the food chain, and their potential for toxicity demonstrate the need for further knowledge. Flow cytometry has become a valuable tool in mycotoxin studies in recent years for the rapid analysis of single cells in a mixture. In toxicology, the power of these methods lies in the possibility of determining a wide range of cell parameters, providing valuable information to elucidate cell growth and viability, metabolic activity, mitochondrial membrane potential and membrane integrity mechanisms. There are studies using flow cytometry technique on Alternaria, Aspergillus, Fusarium and Penicillium mycotoxins including information about cell type, assay conditions and functional parameters. Most of the studies collected in the literature are on deoxynivalenol and zearalenone mycotoxins. Cell cycle analysis and apoptosis are the processes more widely investigated.

Alpha B-crystallin prevents the arrhythmogenic effects of particulate matter isolated from ambient air by attenuating oxidative stress

Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is activated by particulate matter (PM) isolated from ambient air and linked to prolonged repolarization and cardiac arrhythmia. We evaluated whether alpha B-crystallin (CryAB), a heat shock protein, could prevent the arrhythmogenic effects of PM by preventing CaMKII activation. CryAB was delivered into cardiac cells using a TAT-protein transduction domain (TAT-CryAB). ECGs were measured before and after tracheal exposure of diesel exhaust particles (DEP) and each intervention in adult Sprague-Dawley rats. After endotracheal exposure of DEP (200 μg/mL for 30 minutes, n=11), QT intervals were prolonged from 115±14 ms to 144±20 ms (p=0.03), and premature ventricular contractions were observed more frequently (0% vs. 44%) than control (n=5) and TAT-Cry (n=5). However, DEP-induced arrhythmia was not observed in TAT-CryAB (1 mg/kg) pretreated rats (n=5). In optical mapping of Langendorff-perfused rat heats, compared with baseline, DEP infusion of 12.5 μg/mL (n=12) increased apicobasal action potential duration (APD) differences from 2±6 ms to 36±15 ms (p<0.001), APD restitution slope from 0.26±0.07 to 1.19±0.11 (p<0.001) and ventricular tachycardia (VT) from 0% to 75% (p<0.001). DEP infusion easily induced spatially discordant alternans. However, the effects of DEP were prevented by TAT-CryAB (1mg/kg, n=9). In rat myocytes, while DEP increased reactive oxygen species (ROS) generation and phosphated CaMKII, TAT-CryAB prevented these effects. In conclusion, CryAB, a small heat shock protein, might prevent the arrhythmogenic effects of PM by attenuating ROS generation and CaMKII activation.

The non-anticoagulant heparin-like K5 polysaccharide derivative K5-N,OSepi attenuates myocardial ischaemia/reperfusion injury

Heparin and low molecular weight heparins have been demonstrated to reduce myocardial ischaemia/reperfusion (I/R) injury, although their use is hampered by the risk of haemorrhagic and thrombotic complications. Chemical and enzymatic modifications of K5 polysaccharide have shown the possibility of producing heparin-like compounds with low anticoagulant activity and strong anti-inflammatory effects. Using a rat model of regional myocardial I/R, we investigated the effects of an epimerized N-,O-sulphated K5 polysaccharide derivative, K5-N,OSepi, on infarct size and histological signs of myocardial injury caused by 30 min. ligature of the left anterior descending coronary artery followed by 1 or 24 h reperfusion. K5-N,OSepi (0.1-1 mg/kg given i.v. 15 min. before reperfusion) significantly reduced the extent of myocardial damage in a dose-dependent manner. Furthermore, we investigated the potential mechanism(s) of the cardioprotective effect(s) afforded by K5-N,OSepi. In left ventricular samples, I/R induced mast cell degranulation and a robust increase in lipid peroxidation, free radical-induced DNA damage and calcium overload. Markers of neutrophil infiltration and activation were also induced by I/R in rat hearts, specifically myeloperoxidase activity, intercellular-adhesion-molecule-1 expression, prostaglandin-E(2) and tumour-necrosis-factor-α production. The robust increase in oxidative stress and inflammatory markers was blunted by K5-N,OSepi, in a dose-dependent manner, with maximum at 1 mg/kg. Furthermore, K5-N,OSepi administration attenuated the increase in caspase 3 activity, Bid and Bax activation and ameliorated the decrease in expression of Bcl-2 within the ischaemic myocardium. In conclusion, we demonstrate that the cardioprotective effect of the non-anticoagulant K5 derivative K5-N,OSepi is secondary to a combination of anti-apoptotic and anti-inflammatory effects.

Resveratrol attenuates the Na(+)-dependent intracellular Ca(2+) overload by inhibiting H(2)O(2)-induced increase in late sodium current in ventricular myocytes

Background/Aims

Resveratrol has been demonstrated to be protective in the cardiovascular system. The aim of this study was to assess the effects of resveratrol on hydrogen peroxide (H₂O₂)-induced increase in late sodium current (I_Na.L) which augmented the reverse Na⁺-Ca²⁺ exchanger current (I_NCX), and the diastolic intracellular Ca²⁺ concentration in ventricular myocytes.

Methods

I_Na.L, I_NCX, L-type Ca²⁺ current (I_Ca.L) and intracellular Ca²⁺ properties were determined using whole-cell patch-clamp techniques and dual-excitation fluorescence photomultiplier system (IonOptix), respectively, in rabbit ventricular myocytes.

Results

Resveratrol (10, 20, 40 and 80 µM) decreased I_Na.L in myocytes both in the absence and presence of H₂O₂ (300 µM) in a concentration dependent manner. Ranolazine (3–9 µM) and tetrodotoxin (TTX, 4 µM), I_Na.L inhibitors, decreased I_Na.L in cardiomyocytes in the presence of 300 µM H₂O₂. H₂O₂ (300 µM) increased the reverse I_NCX and this increase was significantly attenuated by either 20 µM resveratrol or 4 µM ranolazine or 4 µM TTX. In addition, 10 µM resveratrol and 2 µM TTX significantly depressed the increase by 150 µM H₂O₂ of the diastolic intracellular Ca²⁺ fura-2 fluorescence intensity (FFI), fura-fluorescence intensity change (△FFI), maximal velocity of intracellular Ca²⁺ transient rise and decay. As expected, 2 µM TTX had no effect on I_Ca.L.

Conclusion

Resveratrol protects the cardiomyocytes by inhibiting the H₂O₂-induced augmentation of I_Na.L.and may contribute to the reduction of ischemia-induced lethal arrhythmias.

Intraperitoneal injection of cigarette smoke extract induced emphysema, and injury of cardiac and skeletal muscles in BALB/C mice

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a chronic, progressive, airway disease. In order to recognize mechanisms of COPD, various types of COPD animal models have been established, and the pathogenesis are different. The present study was designed to establish a COPD animal model by intraperitoneal injection of cigarette smoke extract (CSE) in BALB/C mice.

METHODS

Mice were injected intraperitoneally with PBS/CSE and sacrificed at day 28. Pulmonary function, pathology of lung tissue, morphology of hearts and skeletal muscle, leukocytes count and antioxidant activity of bronchoalveolar lavage fluid (BALF), pulmonary parenchymal apoptosis index (AI), expression of cleaved caspase-3, expression of MMP-2 and MMP-9 mRNA, and activity of MMP-2 and MMP-9 in lung tissue were measured.

RESULTS

Intraperitoneal injection of CSE induced pulmonary parenchymal destruction, pulmonary function reduction, leukocytes count, injury of cardiac and peripheral muscles, and increased pulmonary parenchymal AI, cleaved caspase-3 protein, expression of MMP-2 and MMP-9 mRNA, activity of MMP-2 and MMP-9 protein in lung tissue, and suppressed antioxidant activity in BALF (P < 0.05).

CONCLUSIONS

Intraperitoneal injection of CSE produced emphysema, pulmonary parenchymal apoptosis, and injury of cardiac and skeletal muscles in mice. All pathobiologically relevant mechanisms in this model are shared with the COPD patients.

Deficiency of αB crystallin augments ER stress-induced apoptosis by enhancing mitochondrial dysfunction

Endoplasmic reticulum (ER) stress is linked to several pathological conditions including age-related macular degeneration. Excessive ER stress initiates cell death cascades which are mediated, in part, through mitochondrial dysfunction. Here, we identify αB crystallin as an important regulator of ER stress-induced cell death. Retinal pigment epithelial (RPE) cells from αB crystallin (-/-) mice, and human RPE cells transfected with αB crystallin siRNA, are more vulnerable to ER stress induced by tunicamycin. ER stress-mediated cell death is associated with increased levels of reactive oxygen species, depletion of glutathione in mitochondria, decreased superoxide dismutase activity, increased release of cytochrome c, and activation of caspases 3 and 4. The ER stress signaling inhibitors, salubrinal and 4-(2-aminoethyl) benzenesulfonyl fluoride, decrease mitochondrial damage and reduce RPE apoptosis induced by ER stress. Prolonged ER stress decreases levels of αB crystallin, thus exacerbating mitochondrial dysfunction. Overexpression of αB crystallin protects RPE cells from ER stress-induced apoptosis by attenuating increases in Bax, CHOP, mitochondrial permeability transition, and cleaved caspase 3. Thus, these data collectively demonstrate that αB crystallin provides critical protection of mitochondrial function during ER stress-induced RPE apoptosis.

HSPB2 is dispensable for the cardiac hypertrophic response but reduces mitochondrial energetics following pressure overload in mice

Background

CryAB (HspB5) and HspB2, two small heat shock genes located adjacently in the vertebrate genome, are hypothesized to play distinct roles. Mice lacking both cryab and hspb2 (DKO) are viable and exhibit adult-onset degeneration of skeletal muscle but confounding results from independent groups were reported for cardiac responses to different stressful conditions (i.e., ischemia/reperfusion or pressure overload). To determine the specific requirements of HSPB2 in heart, we generated cardiac-specific HSPB2 deficient (HSPB2cKO) mice and examined their cardiac function under basal conditions and following cardiac pressure overload.

Methodology/Principal Findings

Transverse aortic constriction (TAC) or sham surgery was performed in HSPB2cKO mice and their littermates (HSPB2wt mice). Eight weeks after TAC, we found that expression of several small HSPs (HSPB2, 5, 6) was not markedly modified in HSPB2wt mice. Both cardiac function and the hypertrophic response remained similar in HSPB2cKO and HSPB2wt hearts. In addition, mitochondrial respiration and ATP production assays demonstrated that the absence of HSPB2 did not change mitochondrial metabolism in basal conditions. However, fatty acid supported state 3 respiration rate (ADP stimulated) in TAC operated HSPB2cKO hearts was significantly reduced in compared with TAC operated HSPB2wt mice (10.5±2.2 vs. 12.8±2.5 nmol O₂/min/mg dry fiber weight, P<0.05), and ATP production in HSPB2cKO hearts was significantly reduced in TAC compared with sham operated mice (29.8±0.2 vs. 21.1±1.8 nmol ATP/min/mg dry fiber weight, P<0.05). Although HSPB2 was not associated with mitochondria under cardiac stress, absence of HSPB2 led to changes in transcript levels of several metabolic and mitochondrial regulator genes.

Conclusions/Significance

The present study indicates that HSPB2 can be replaced by other members of the multigene small HSP family under basal conditions while HSPB2 is implicated in the regulation of metabolic/mitochondrial function under cardiac stress such pressure overload.

Small heat shock proteins in redox metabolism: implications for cardiovascular diseases

A timely review series on small heat shock proteins has to appropriately examine their fundamental properties and implications in the cardiovascular system since several members of this chaperone family exhibit robust expression in the myocardium and blood vessels. Due to energetic and metabolic demands, the cardiovascular system maintains a high mitochondrial activity but irreversible oxidative damage might ensue from increased production of reactive oxygen species. How equilibrium between their production and scavenging is achieved becomes paramount for physiological maintenance. For example, heat shock protein B1 (HSPB1) is implicated in maintaining this equilibrium or redox homeostasis by upholding the level of glutathione, a major redox mediator. Studies of gain or loss of function achieved by genetic manipulations have been highly informative for understanding the roles of those proteins. For example, genetic deficiency of several small heat shock proteins such as HSPB5 and HSPB2 is well-tolerated in heart cells whereas a single missense mutation causes human pathology. Such evidence highlights both the profound genetic redundancy observed among the multigene family of small heat shock proteins while underscoring the role proteotoxicity plays in driving disease pathogenesis. We will discuss the available data on small heat shock proteins in the cardiovascular system, redox metabolism and human diseases. From the medical perspective, we envision that such emerging knowledge of the multiple roles small heat shock proteins exert in the cardiovascular system will undoubtedly open new avenues for their identification and possible therapeutic targeting in humans. This article is part of a Directed Issue entitled: Small HSPs in physiology and pathology.

Mechanisms mediating propofol protection of pulmonary epithelial cells against lipopolysaccharide-induced cell death

Propofol (2,6-diisopropylphenol) is an anaesthetic agent with anti-oxidant properties. The aim of the present study was to determine whether propofol can protect pulmonary epithelial (A549) cells against lipopolysaccharide (LPS)-induced cell death and, if so, the mechanisms involved. The effects of LPS alone and in combination with propofol on A549 cell death were investigated. Cell viability was determined using the colourimetric 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Apoptotic A549 cells were detected by flow cytometry, as propidium iodide-negative and annexin-V-positive cells, and terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL). Mitochondrial membrane potential (MMP), caspase 9 activity, Ca(2+) concentrations and reactive oxygen species (ROS) were analysed by immunofluorescent methods. Aconitase 2 (ACO2), microtubule-associated light chain 3 (LC3) and beclin-1 levels were evaluated using reverse transcription-polymerase chain reaction and/or western blot analysis. Exposure of A549 cells to 1-50 μg/mL LPS for 3-24 h resulted in the concentration- and time-dependent induction of cell death. Cell apoptosis accounted for approximately 77% of cell death induced by LPS. Propofol (5-150 μmol/L) concentration-dependently inhibited LPS-induced A549 cell death. This protective effect of propofol was accompanied by prevention of LPS-induced mitochondrial dysfunction (reductions in MMP, ACO2 expression and ATP) and was associated with the inhibition of LPS-induced activation of apoptotic signals (caspase 9 activity, ROS overproduction and Ca(2+) accumulation). In addition, propofol blocked LPS-induced overexpression of the autophagy-associated proteins LC3 and beclin-1. The data indicate that propofol protects A549 cells against LPS-induced apoptosis, and probably autophagy, by blocking LPS-induced activation of ROS/caspase 9 pathways and upregulation of LC3 and beclin-1, respectively.

Heparosan-derived heparan sulfate/heparin-like compounds: one kind of potential therapeutic agents

Heparan sulfate (HS) is a highly sulfated glycosaminoglycan and exists in all animal tissues. HS and heparin are very similar, except that heparin has higher level of sulfation and higher content of iduronic acid. Despite the fact that it is a century-old drug, heparin remains as a top choice for treating thrombotic disorders. Pharmaceutical heparin is derived from porcine intestine or bovine lung via a long supply chain. This supply chain is vulnerable to the contamination of animal pathogens. Therefore, new methods for manufacturing heparin or heparin-like substances devoid of animal tissues have been explored by many researchers, among which, modifications of heparosan, the capsular polysaccharide of Escherichia coli K5 strain, is one of the promising approaches. Heparosan has a structure similar to unmodified backbone of natural HS and heparin. It is feasible to obtain HS or heparin derivatives by modifying heparosan with chemical or enzymatic methods. These derivatives display different biological activities, such as anticoagulant, anti-inflammatory, anticancer, and antiviral activities. This review focuses on the recent studies of synthesis, activity, and structure-activity relationship of HS/heparin-like derivatives prepared from heparosan.

Association of Stat3 with HSF1 plays a critical role in G-CSF-induced cardio-protection against ischemia/reperfusion injury

Granulocyte colony-stimulating factor (G-CSF) has been shown to be cardio-protective against ischemia through activating Jak2/Stat3 pathway, however, the mechanism is unclear. Heat shock transcription factor 1 (HSF1), a definite endogenous protective protein in cardiomyocytes, may interact with Stat family under stress conditions. We hypothesized that G-CSF could induce cardio-protection against ischemia/reperfusion (I/R) through association of HSF1 with Stat3. To test the hypothesis, we built cardiac I/R injury model with HSF1 knockout (KO) mice and wild type (WT) mice by occlusion of the left anterior descending (LAD) coronary artery for 30min and subsequent release of the occlusion for 24h. These mice were administered with G-CSF (100μg/kg/day) or vehicle subcutaneously for 3days before surgery. As expected, G-CSF induced significant cardio-protections against I/R injury, characterized by higher ejection fraction (EF%), lower left ventricular end diastolic pressure (LVEDP), increased dp/dt value and decreased infarct area as compared with the vehicle treatment in WT mice. In HSF1-KO mice, however, these cardio-protections induced by G-CSF were greatly attenuated. Inhibition of oxidative stress-induced cardiomyocyte apoptosis by G-CSF also disappeared due to the deficiency of HSF1 in vitro and in vivo. Furthermore, G-CSF increased the phosphorylation and the association of Stat3 with HSF1, which enhanced transcriptional activity of HSF1. Inhibition of either Stat3 or HSF1 by pharmacological agents suppressed G-CSF-induced association of the two proteins and anti-apoptotic effect on cardiomyocytes. Our data suggest that G-CSF stimulates phosphorylation and association of Stat3 with HSF1 and therefore enhances transcriptional activity of HSF1, leading to the cardio-protection against I/R injury.

Role of ranolazine in angina, heart failure, arrhythmias, and diabetes

Ranolazine which is currently approved as an antianginal agent reduces the Na-dependent Ca overload via inhibition of the late sodium current (late I(Na)) and thus improves diastolic tone and oxygen handling during myocardial ischemia. According to accumulating evidence ranolazine also exerts beneficial effects on diastolic and systolic heart failure where late I(Na) was also found to be elevated. Moreover, late I(Na) plays a crucial role as an arrhythmic substrate. Ranolazine has been described to have antiarrhythmic effects on ventricular as well as atrial arrhythmias without any proarrythmia or severe organ toxicity as it is common for several antiarrhythmic drugs. In patients with diabetes, treatment with ranolazine led to a significant improvement of glycemic control. In this article possible new clinical indications of the late I(Na)-inhibitor ranolazine are reviewed. We summarize novel experimental and clinical studies and discuss the significance of the available data.

Comparison of effectiveness and safety of ranolazine versus amiodarone for preventing atrial fibrillation after coronary artery bypass grafting

Atrial fibrillation (AF) is common after coronary artery bypass grafting (CABG) and increases the morbidity and cost. Amiodarone reduces AF after CABG. Ranolazine, an antianginal agent, also prolongs atrial refractoriness and inhibits after depolarizations and triggered activity; effects that could decrease AF after CABG. The present study compared amiodarone versus ranolazine for the prevention of AF after CABG. A retrospective cohort study of patients undergoing CABG at Aspirus Hospital from June 2008 to April 2010. The patients received either amiodarone (400 mg preoperatively followed by 200 mg twice daily for 10 to 14 days) or ranolazine (1,500 mg preoperatively followed by 1,000 mg twice daily for 10 to 14 days). The primary end point was any identified AF after CABG. A total of 393 consecutive patients undergoing CABG (mean age 65 ± 10 years, 72% men) received either amiodarone (n = 211 [53.7%]) or ranolazine (n = 182 [46.3%]). AF occurred in 26.5% of the amiodarone-treated patients compared to 17.5% of the ranolazine-treated patient (p = 0.035). The univariate predictors of AF included amiodarone use, age, chronic lung disease, and congestive heart failure. The multivariate predictors of AF included amiodarone use (odds ratio 1.7, 95% confidence interval 1.01 to 2.91, p = 0.045 vs ranolazine), age (odds ratio 2.2 per 10 years, 95% confidence interval 1.63 to 2.95, p <0.001), and chronic lung disease (odds ratio 1.86, 95% confidence interval 1.00 to 3.43, p = 0.049). No difference was found in the risk of adverse events between the 2 therapies. In conclusion, ranolazine was independently associated with a significant reduction of AF compared to amiodarone after CABG, with no difference in the incidence of adverse events. Randomized studies should be conducted to confirm these results.

Matrix metalloproteinase-1 induces cleavage of exogenous alphaB-crystallin transduced by a cell-penetrating peptide

Cell-penetrating peptides (CPPs), including TAT-CPP, have been used to deliver exogenous proteins into living cells. Although a number of proteins fused to TAT-CPP can be delivered into various cells, little is known about the proteolytic cleavage of TAT-fusion proteins in cells. In this study, we demonstrate that a small heat shock protein (sHSP), alphaB-crystallin (αB-crystallin), delivered by TAT-CPP is susceptible to proteolytic cleavage by matrix metalloproteinase-1 (MMP-1) in cardiac myoblast H9c2 cells. Recombinant TAT-αB-crystallin was efficiently transduced into H9c2 cells. For a few hours following protein transduction, generation of a 14-kDa fragment, a cleavage band of TAT-αB-crystallin, increased in a time-dependent manner. This fragment was observed only in detergent-insoluble fractions. Interestingly, treatment with MMP inhibitors blocked the cleavage of TAT-αB-crystallin. In test tubes, recombinant MMP-1 processed TAT-αB-crystallin to generate the major cleavage fragment 14-kDa, as observed in the cells treated with TAT-αB-crystallin. The N-terminal sequences of the 14-kDa fragment were identified as Leu-Arg-Ala-Pro-Ser-Trp-Phe, indicating that this fragment is generated by cleavage at Phe54-Leu55 of αB-crystallin. The MMP-1-selective inhibitor abolished the production of 14-kDa fragments in cells. In addition, the cleaved fragment of TAT-αB-crystallin was significantly reduced in cells transfected with MMP-1 siRNA. Moreover, the enzymatic activity of MMP-1 was markedly increased in TAT-αB-crystallin-treated cells. TAT-αB-crystallin has a cytoprotective effect on H9c2 cells under hypoxic insult, moreover, MMP-1-selective inhibitor treatment led to even increased cell viability. These results suggest that MMP-1 is responsible for proteolytic cleavage of TAT-αB-crystallin during its intracellular transduction in H9c2 cells.