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In vitro modelling the complex (patho‐) physiological conditions of the heart is a major challenge in cardiovascular research. In recent years, methods based on three‐dimensional (3D) cultivation approaches have steadily evolved to overcome the major limitations of conventional adherent two‐dimensional (2D) monolayer cultivation. These 3D approaches aim to study, reproduce or modify fundamental native features of the heart such as tissue organization and cardiovascular microenvironment. Therefore, these systems have great potential for (patient‐specific) disease research, for the development of new drug screening platforms, and for the use in regenerative and replacement therapy applications. Consequently, continuous improvement and adaptation is required with respect to fundamental limitations such as cardiomyocyte maturation, scalability, heterogeneity, vascularization, and reproduction of native properties. In this review, 2D monolayer culturing and the 3D in vitro systems of cardiac spheroids, organoids, engineered cardiac microtissue and bioprinting as well as the ex vivo technique of myocardial slicing are introduced with their basic concepts, advantages, and limitations. Furthermore, recent advances of various new approaches aiming to extend as well as to optimize these in vitro and ex vivo systems are presented. [ABSTRACT FROM AUTHOR]

It is important to note that the authors provide evidence that DCHS2 is both necessary and sufficient for lncExACT1's effects on cardiomyocyte growth, where DCHS2 knockdown prevented the pathological hypertrophy seen with lncExACT1 overexpression, and DCHS2 overexpression blocked the physiological hypertrophy seen with lncExACT1 knockdown. Keywords: Editorials; exercise; heart failure; hypertrophy; RNA; long noncoding EN Editorials exercise heart failure hypertrophy RNA long noncoding 1234 1237 4 04/21/22 20220419 NES 220419 The Heart Institute, Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, OH (C.A.M.). DCHS2 is positively regulated by lncExACT1, with lncExACT1 overexpression in mice resulting in DCHS2 upregulation and lncExACT1 inhibition correlating with DCHS2 downregulation. [Extracted from the article]

Despite the advances in treatment options, cardiovascular disease (CVDs) remains the leading cause of death over the world. Chronic inflammatory response and irreversible fibrosis are the main underlying pathophysiological causes of progression of CVDs. In recent decades, cardiac macrophages have been recognized as main regulatory players in the development of these complex pathophysiological conditions. Numerous approaches aimed at macrophages have been devised, leading to novel prospects for therapeutic interventions. Our review covers the advancements in macrophage-centric treatment plans for various pathologic conditions and examines the potential consequences and obstacles of employing macrophage-targeted techniques in cardiac diseases. [ABSTRACT FROM AUTHOR]

Heart failure remains a leading cause of morbidity and mortality globally. Within the last 5 years, many new developments have been seen in the area of heart failure, including completely new therapies, mechanistic insights, as well as novel strategies to phenotype and segment the condition. Borlaug I et al i .[1] focus on the emerging problem of obesity and heart failure with preserved ejection fraction (HFpEF), which represents indeed one of the greatest unmet health problems in the field of cardiovascular medicine in the 21st century. [Extracted from the article]

Transcription of a large part of the human genome results in RNA transcripts that have limited or no protein-coding potential. These include long noncoding RNAs (lncRNAs), which are defined as being ≥200 nucleotides long. Unlike microRNAs, which have been extensively studied, little is known about the functional role of lncRNAs. However, studies over the past 5 years have shown that lncRNAs interfere with tissue homeostasis and have a role in pathological processes, including in the kidney and heart. The developmental expression of the microRNA sponge H19, for example, is altered in the kidneys of embryos carried by hyperglycaemic mothers, and the lncRNA Malat1 regulates hyperglycaemia-induced inflammation in endothelial cells. Putative roles for other lncRNAs have been identified in conditions such as heart failure, cardiac autophagy, hypertension, acute kidney injury, glomerular diseases, acute allograft rejection and renal cell carcinoma. This Review outlines our current understanding of the role and function of lncRNAs in kidney and cardiovascular disease as novel important regulators and potential therapeutic entry points of disease progression. [ABSTRACT FROM AUTHOR]

Autophagy is an important quality control mechanism present in all cells to maintain their cellular homeostasis. An imbalance in the autophagic process had been reported in numerous diseases including cardiovascular disease and is associated with serious consequences. Thus, knowledge of key regulators of cardiac autophagy is helpful to regain a balanced autophagic activity and to maintain healthy myocardial function. In this review we summarize all microRNAs which had been reported to regulate cardiac autophagy to date. In addition, we discuss long noncoding RNAs and circular RNAs as potential modulators of autophagy. Altering non-coding RNAs in-vivo by novel therapeutics offers a promising approach to treat autophagy-related diseases. [ABSTRACT FROM AUTHOR]

Cardiac stress leads to remodelling of cardiac tissue, which often progresses to heart failure and death. Part of the remodelling process is the formation of fibrotic tissue, which is caused by exaggerated activity of cardiac fibroblasts leading to excessive extracellular matrix production within the myocardium. Noncoding RNAs (ncRNAs) are a diverse group of endogenous RNA-based molecules, which include short (~22 nucleotides) microRNAs and long ncRNAs (of >200 nucleotides). These ncRNAs can regulate important functions in many cardiovascular cells types. This Review focuses on the role of ncRNAs in cardiac fibrosis; specifically, ncRNAs as therapeutic targets, factors for direct fibroblast transdifferentation, their use as diagnostic and prognostic markers, and their potential to function as paracrine modulators of cardiac fibrosis and remodelling. [ABSTRACT FROM AUTHOR]

Highlights: [•] MicroRNAs have been recognized in various biological and disease processes. [•] MicroRNAs remain stable in the extracellular space, and take part in cell-to cell communications. [•] MicroRNAs are attractive, non-invasively detectable markers of biological processes and disease development. [•] Deregulated microRNAs can be targeted by synthetic oligonucleotides, as an innovative novel therapeutic approach. [•] The expanding microRNA field is facing many analytical challenges. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases are a major cause of human morbidity and mortality, posing a high socioeconomic burden on the health sector worldwide. microRNAs (miRNAs) constitute a new class of unique molecular regulators involved in the pathophysiology of a wide range of disorders. Studies in the past decade have identified miRNA signatures of various cardiovascular disorders and successfully validated miRNA-based therapeutic options in various small and a few large experimental cardiovascular disease models. In these models, researchers manipulate the expression of miRNAs and downstream signaling cascades, aiming to prevent and cure cardiovascular disease. Here, we review and discuss the recent reports on the in vivo use of miRNA animal models and miRNA therapeutic development as well as provide an outlook for clinical applications in the near future. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases are a major cause of human morbidity and mortality, posing a high socioeconomic burden on the health sector worldwide. microRNAs (miRNAs) constitute a new class of unique molecular regulators involved in the pathophysiology of a wide range of disorders. Studies in the past decade have identified miRNA signatures of various cardiovascular disorders and successfully validated miRNA-based therapeutic options in various small and a few large experimental cardiovascular disease models. In these models, researchers manipulate the expression of miRNAs and downstream signaling cascades, aiming to prevent and cure cardiovascular disease. Here, we review and discuss the recent reports on the in vivo use of miRNA animal models and miRNA therapeutic development as well as provide an outlook for clinical applications in the near future. [ABSTRACT FROM AUTHOR]

Abstract: Exosomes are small membrane vesicles of endosomal origin, which are secreted from a variety of cell types. During the 1980s exosomes were first described as organelles to remove cell debris and unwanted molecules. The discovery that exosomes contain proteins, messenger and microRNAs suggests a role as mediators in cell-to-cell communication. Exosomes can be transported between different cells and influence physiological pathways in the recipient cells. In the present review, we will summarize the biological function of exosomes and their involvement in physiological and pathological processes. Moreover, the potential clinical application of exosomes as biomarkers and therapeutic tools will be discussed. [Copyright &y& Elsevier]

Myocardial infarction causes a massive loss of cardiomyocytes (CMs), which can lead to heart failure accompanied by fibrosis, stiffening of the heart, and loss of function. Heart failure causes high mortality rates and is a huge socioeconomic burden, which, based on diets and lifestyle in the developed world, is expected to increase further in the next years. At present, the only curative treatment for heart failure is heart transplantation associated with a number of limitations such as donor organ availability and transplant rejection among others. Thus, the development of cellular reprogramming and defined differentiation protocols provide exciting new possibilities for cell therapy approaches and which opened up a new era in regenerative medicine. Consequently, tremendous research efforts were undertaken to gain a detailed molecular understanding of the reprogramming processes and the in vitro differentiation of pluripotent stem cells into functional CMs for transplantation into the patient's injured heart. In the last decade, non-coding RNAs, particularly microRNAs, long non-coding RNAs, and circular RNAs emerged as critical regulators of gene expression that were shown to fine-tune cellular processes both on the transcriptional and the post-transcriptional level. Unsurprisingly, also cellular reprogramming, pluripotency, and cardiac differentiation and maturation are regulated by non-coding RNAs. In here, we review the current knowledge on non-coding RNAs in these processes and highlight how their modulation may enhance the quality and quantity of stem cells and their derivatives for safe and efficient clinical application in patients with heart failure. In addition, we summarize the clinical cell therapy efforts undertaken thus far. [ABSTRACT FROM AUTHOR]

Takotsubo syndrome (TTS) is a severe but reversible acute heart failure syndrome that occurs following high catecholaminergic stress. TTS patients are similar to those with acute coronary syndrome, with chest pain, dyspnoea and ST segment changes on electrocardiogram, but are characterised by apical akinesia of the left ventricle, with basal hyperkinesia in the absence of culprit coronary artery stenosis. The pathophysiology of TTS is not completely understood and there is a paucity of evidence to guide treatment. The mechanisms of TTS are thought to involve catecholaminergic myocardial stunning, microvascular dysfunction, increased inflammation and changes in cardiomyocyte metabolism. Here, we summarise the available literature to focus on the molecular basis for the pathophysiology of TTS to advance the understanding of the condition. [ABSTRACT FROM AUTHOR]

Abstract: MicroRNAs (miRNAs) are small non-coding RNAs, that control diverse cellular functions by either promoting degradation or inhibition of target messenger RNA translation. An aberrant expression profile of miRNAs has been linked to human diseases, including cardiovascular dysfunction. This review summarizes the latest insights in the identification of vascular-specific miRNAs and their targets, as well as their roles and mechanisms in the vasculature. Furthermore, we discuss how manipulation of these miRNAs could represent a novel therapeutic approach in the treatment of vascular dysfunction. [Copyright &y& Elsevier]

AbstractEndothelial injury and dysfunction are critical events in the pathogenesis of cardiovascular disease. During these processes, an impaired balance of nitric oxide bioavailability and oxidative stress is mechanistically involved. Circulating angiogenic cells (including early and late outgrowth endothelial progenitor cells (EPC)) contribute to formation of new blood vessels, neovascularization, and homeostasis of the vasculature, and are highly sensitive for misbalance between NO and oxidative stress. We here review the role of the endothelial nitric oxide synthase and oxidative stress producing enzyme systems in EPC during cardiovascular disease. We also focus on the underlying molecular mechanisms and potential emerging drug- and gene-based therapeutic strategies to improve EPC function in cardiovascular diseased patients. Antioxid. Redox Signal.15, 933–948. [ABSTRACT FROM AUTHOR]

AbstractSymptomatic coronary artery disease (CAD) is usually treated with organic nitrates. Endothelial progenitor cells (EPCs) are a circulating cell population participating in vascular homeostasis in a nitric oxide-dependent manner. We investigated the effects of the nitric oxide donors isosorbide dinitrate (ISDN) and pentaerythritol tetranitrate (PETN) on EPC and endothelial function in patients with symptomatic CAD. We randomized 36 patients with angiographically proven CAD to treatment with either ISDN (40 mg retarded release orally two times per day; n= 18) or PETN (80 mg orally two times per day; n= 18) for 14 days (clinical trial number: NCT01030367). PETN treatment substantially increased numbers of circulating CD34+/KDR+EPCs (p= 0.02), whereas no effects were observed in patients treated with ISDN. EPC function assessed by formation of endothelial colonies was enhanced by twofold (p= 0.04) in patients treated with PETN. No changes were observed after ISDN treatment. Endothelial function, assessed by peripheral arterial tonometry, remained unchanged during PETN treatment, but was significantly impaired in patients treated with ISDN. Treatment of symptomatic CAD patients with PETN for 14 days significantly increased levels of circulating EPC and improved markers for EPC function, whereas ISDN was without effects on EPCs and worsened endothelial function. Antioxid. Redox Signal.15, 925–931. [ABSTRACT FROM AUTHOR]

Background: Oleic acid is a major systemically circulating fatty acid in humans with atheroprotective and immunomodulatory properties. As of today, the contribution of individual cytochrome P450 (CYP) mono-oxygenases to the epoxidation of this fatty acid is unknown. Furthermore, the extent of the oleic acid oxidation product cis-9,10-epoxyoctadecanoic acid ( cis-EODA) in humans and its plasma levels in patients with impaired liver function are not known. Patients and methods: We studied cis-EODA in plasma of patients suffering from chronic liver diseases, a condition that often displays impaired liver CYP enzyme activities. Fifteen CYP mono-oxygenases were investigated in vitro as a potential source of cis-EODA. Results: Strikingly, plasma levels of cis-EODA were significantly repressed ( P<0.0005) when patients with liver impairment ( n=16) were compared with healthy subjects ( n=14). Production of cis-EODA was catalysed by CYP in the following order: 2C8, 2C9, 2C19, 3A4, 1A2 and CYP3A7. Conclusion: cis-EODA plasma concentrations are decreased in hepatic disease with impaired liver function. Oleic acid is primarily oxidized to oleic acid oxide ( cis-EODA) by CYP2C and CYP3A mono-oxygenases. The liver is the major organ responsible for the oxidation of oleic acid to cis-EODA, and thus, cis-EODA may be a suitable biomarker to assess liver function. [ABSTRACT FROM AUTHOR]

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by ongoing endothelial dysfunction and vascular remodeling. Endothelial progenitor cells (EPCs), mobilized from the bone marrow and resident locally in the lung, are thought to be important in maintaining vascular homeostasis; and there is growing interest in the potential therapeutic use of EPCs in PAH. Putative progenitor cells have also been localized to vascular lesions in the lungs of patients with PAH, raising questions about their role in vascular remodeling and disease progression. Further studies are required to determine the identity, origin, and function of progenitor cells in pulmonary vascular lesions and to establish whether the mobilization and recruitment of EPCs in the hypertensive pulmonary vascular system represent a protective process and/or involvement in the pathogenesis of PAH. [Copyright &y& Elsevier]

MicroRNAs comprise a broad class of small non-coding RNAs that control expression of complementary target messenger RNAs. Dysregulation of microRNAs by several mechanisms has been described in various disease states including cardiac disease. Whereas previous studies of cardiac disease have focused on microRNAs that are primarily expressed in cardiomyocytes, the role of microRNAs expressed in other cell types of the heart is unclear. Here we show that microRNA-21 (miR-21, also known as Mirn21) regulates the ERK–MAP kinase signalling pathway in cardiac fibroblasts, which has impacts on global cardiac structure and function. miR-21 levels are increased selectively in fibroblasts of the failing heart, augmenting ERK–MAP kinase activity through inhibition of sprouty homologue 1 (Spry1). This mechanism regulates fibroblast survival and growth factor secretion, apparently controlling the extent of interstitial fibrosis and cardiac hypertrophy. In vivo silencing of miR-21 by a specific antagomir in a mouse pressure-overload-induced disease model reduces cardiac ERK–MAP kinase activity, inhibits interstitial fibrosis and attenuates cardiac dysfunction. These findings reveal that microRNAs can contribute to myocardial disease by an effect in cardiac fibroblasts. Our results validate miR-21 as a disease target in heart failure and establish the therapeutic efficacy of microRNA therapeutic intervention in a cardiovascular disease setting. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are endogenous, small ribonucleotides regulating the translation of target messenger RNAs that have been shown to be involved in orchestrating growth, development, function, and stress responses of various organs, including the heart. Muscle miRNAs are mainly controlled by a network of myogenic transcription factors, and throughout cardiac development they fine-tune regulatory protein levels in a spatiotemporal manner. Recent profiling studies revealed that miRNA expression patterns are derailed in both human cardiac disease and animal models of cardiac hypertrophy and failure. Modulation of miRNA expression in vitro as well as in vivo has revealed an important role of miRNAs in regulating heart function, particularly cardiac growth and conductance. Here, we overview the recent findings on miRNAs in cardiac development and disease and report the latest advances in the identification and validation of miRNA targets, which are important for a comprehensive understanding of cardiac miRNA function. Finally, we focus on the development and use of miRNA antagonists (antagomirs) to target miRNAs in vivo, which may translate into novel therapeutic strategies for heart disease in the future. [ABSTRACT FROM PUBLISHER]

Activation of the lectin-like oxLDL receptor (LOX-1) promotes atherosclerosis. Oxidized LDL (oxLDL) increases production of reactive oxygen species (ROS) and leads to the development of endothelial dysfunction. The molecular causes for oxLDL to induce oxidative DNA damage and metabolic dysfunction remain uncertain. Here we report treatment of cultured human coronary arterial endothelial cells (HCAEC) with oxLDL to cause oxidative DNA damage as determined by a 3-fold increase in 8-OH-desoxyguanosine adduct formation and a 4-fold induction of the growth arrest and DNA damage-inducible transcripts GADD45 and GADD153. Oxidative stress resulted in activation of Oct-1, a transcriptional repressor of various vascular cytochrome P450 (CYP) monooxygenases. Activation of Oct-1 was protein kinase C (PKC)-mediated. Binding of Oct-1 to promoter sequences of CYP monooxygenases was increased upon treatment of HCAEC with oxLDL. This resulted in repressed production of endothelium-derived hyperpolarization factor 11,12-epoxyeicosatrieonic acid. Small interference RNA-mediated functional knockdown of Oct-1 prevented oxLDL-mediated silencing of CYP expression. Inhibition of LOX-1 attenuated oxLDL-mediated endothelial DNA damage, Oct-1/DNA binding, and reversed impaired production of EDHF. Taken collectively, oxLDL induced oxidative DNA damage and activation of Oct-1 to result in metabolic dysfunction of coronary arterial endothelium. [ABSTRACT FROM AUTHOR]

Xenobiotic induced liver injury is a leading cause for drug withdrawal and toxicogenomics may help to identify molecular causes. Here we report studies with cultures of human hepatocytes to detect early responses of liver toxicity upon treatment with the hepatotoxin Aroclor 1254. We studied transcript abundance of 302 genes with biological functions in detoxification, cell proliferation, tumor development, stress response, signal transduction, apoptosis and cell cycle regulation. More than 40 genes were regulated by at least twofold change, the majority coding for xenobiotic defense. In the case of CYP monooxygenases induction of coded protein was confirmed by Western immunoblotting whereas catalytic activities were determined by assaying for testosterone hydroxylase activity. There was good agreement between gene and protein expression and enzyme activity of CYP monooxygenases. In conclusion, xenobiotic induced hepatotoxicity may arise via several mechanisms and gene expression profiling helps to pinpoint location and pathways perturbed by drugs and chemicals. [ABSTRACT FROM AUTHOR]

Abstract: Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthesis, is hydrolyzed to dimethylamine (DMA) and l-citrulline by the enzyme dimethylarginine dimethylaminohydrolase (DDAH). In the present article we report on a GC–MS assay for DDAH activity in rat liver homogenate in phosphate buffered saline. The method is based on the quantitative determination of ADMA-derived DMA by GC–MS as the pentafluorobenzamide derivative. Quantification was performed by selected-ion monitoring of the protonated molecules at m/z 240 for DMA and m/z 246 for the internal standard (CD3)2NH in the positive-ion chemical ionization mode. The assay was applied to determine the enzyme kinetics in rat liver, the hepatic DDAH activity in streptozotocin-induced (50mg/kg) diabetes in rats, and to evaluate the importance of S-nitrosothiols as DDAH inhibitors. The K M and V max values were determined to be 60μM ADMA and 12.5pmol DMA/minmg liver corresponding to 166pmol DMA/minmg protein. Typical DDAH activity values measured in rat liver homogenate were 8.7pmol DMA/minmg liver at added ADMA concentration of 100μM. DDAH activity was found to be 1.7-fold elevated in diabetic as compared to non-diabetic rats (P =0.01). The SH-specific agents HgCl2, S-nitrosocysteine ethyl ester (SNACET), a synthetic lipophilic S-nitrosothiol, S-nitrosoglutathione (GSNO), S-nitrosocysteine (CysNO) and S-nitrosohomocysteine (HcysNO) were found to inhibit DDAH activity in rat liver homogenate. The IC50 values for HcysNO, SNACET, CysNO and GSNO were estimated to be 300, 500, 700 and 1000μM, respectively. Oral administration of 15N-labelled SNACET to two healthy volunteers (1μmol/kg) resulted in elevated urinary excretion of 15N-labelled nitrite and nitrate, but did not reduce creatinine-corrected excretion of DMA in the urine. Our results suggest that inhibition of DDAH activity on the basis of reversible nitros(yl)ation or irreversible N-thiosulfoximidation of the sulfhydryl group of the cysteine moiety involved in the catalytic process is most likely not a rationale design of DDAH inhibitors. A major advantage of the present GC–MS assay over other assays is that DDAH activity is assessed by measuring the formation of the specific enzymatic product DMA but not the formation of unlabelled or (radio)labelled l-citrulline or the decay of the substrate ADMA. The GC–MS assay reported here should be suitable to probe for DDAH activity in various disease models. [Copyright &y& Elsevier]

Abstract: Dimethylamine [DMA, (CH3)2NH)] is abundantly present in human urine. Main sources of urinary DMA have been reported to include trimethylamine N-oxide, a common food component, and asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthesis. ADMA is excreted in the urine in part unmetabolized and in part after hydrolysis to DMA by dimethylarginine dimethylaminohydrolase (DDAH). Here we describe a GC–MS method for the accurate and rapid quantification of DMA in human urine. The method involves use of (CD3)2NH as internal standard, simultaneous derivatization with pentafluorobenzoyl chloride and extraction in toluene, and selected-ion monitoring of m/z 239 for DMA and m/z 245 for (CD3)2NH in the electron ionization mode. GC–MS analysis of urine samples from 10 healthy volunteers revealed a DMA concentration of 264±173μM equivalent to 10.1±1.64μmol/mmol creatinine. GC–tandem MS analysis of the same urine samples revealed an ADMA concentration of 27.3±15.3μM corresponding to 1.35±1.2μmol/mmol creatinine. In these volunteers, a positive correlation (R =0.83919, P =0.0024) was found between urinary DMA and ADMA, with the DMA/ADMA molar ratio being 10.8±6.2. Elevated excretion rates of DMA (52.9±18.5μmol/mmol creatinine) and ADMA (3.85±1.65μmol/mmol creatinine) were found by the method in 49 patients suffering from coronary artery disease, with the DMA/ADMA molar ratio also being elevated (16.8±12.8). In 12 patients suffering from end-stage liver disease, excretion rates of DMA (47.8±19.7μmol/mmol creatinine) and ADMA (5.6±1.5μmol/mmol creatinine) were found to be elevated, with the DMA/ADMA molar ratio (9.17±4.2) being insignificantly lower (P =0.46). Between urinary DMA and ADMA there was a positive correlation (R =0.6655, P <0.0001) in coronary artery disease, but no correlation (R =0.27339) was found in end-stage liver disease. [Copyright &y& Elsevier]

Abstract: Nitric oxide (NO) produced by NO synthases (NOS) regulates a wide range of cellular functions. Analysis by gene arrays provides valuable information for identifying important elements of the cellular responses to NO. Such screening tools might be useful to elucidate NO-responsive regulators, which play a central role in mediating NO effects. Although the final importance of a particular gene is determined by the encoded protein and further protein modifications, measurements of RNA levels have proven to be partly valuable in identifying the molecular changes that occur in cells. Microarray technology permits large-scale and genome-wide analysis of gene expression from multiple samples. We review the current knowledge of the use of microarray gene expression screening in elucidating the effects of NO on various cells and tissues. We also point out the limitations of general microarray-based gene expression analyses and especially when investigating the effects of NO. [Copyright &y& Elsevier]

Uncoupling of the endothelial nitric oxide synthase (eNOS) resulting in superoxide anion (O 2-) formation instead of nitric oxide (NO) causes diabetic endothelial dysfunction. eNOS regulates mobilization and function of endothelial progenitor cells (EPCs), key regulators of vascular repair. We postulate a role of eNOS uncoupling for reduced number and function of EPC in diabetes. EPC levels in diabetic patients were significantly reduced compared with those of control subjects. EPCs from diabetic patients produced excessive O 2- and showed impaired migratory capacity compared with nondiabetic control subjects. NOS inhibition with N[sup G]-nitro-L-arginine attenuated O 2- production and normalized functional capacity of EPCs from diabetic patients. Glucose-mediated EPC dysfunction was protein kinase C dependent, associated with reduced intracellular BH4 (tetrahydrobiopterin) concentrations, and reversible after exogenous BH4 treatment. Activation of NADPH oxidases played an additional but minor role in glucose-mediated EPC dysfunction. In rats with streptozotocin-induced diabetes, circulating EPCs were reduced to 39 ± 5% of controls and associated with uncoupled eNOS in bone marrow. Our results identify uncoupling of eNOS in diabetic bone marrow, glucose-treated EPCs, and EPCs from diabetic patients resulting in eNOS-mediated O2- production. Subsequent reduction of EPC levels and impairment of EPC function likely contributes to the pathogenesis of vascular disease in diabetes. Diabetes 56: 666-674, 2007 [ABSTRACT FROM AUTHOR]

BACKGROUND: Cytochrome P450 monooxygenases (CYP) play an important role in the defense against inhaled toxicants, and expression of CYP enzymes may differ among various lung cells and tissue compartments. METHODS: We studied the effects of tobacco smoke in volunteers and investigated gene expression of 19 CYPs and 3 flavin-containing monooxygenases, as well as isoforms of gluthathione S-transferases (GST) and uridine diphosphate glucuronosyltransferases (UGT) and the microsomal epoxide hydrolase (EPHX1) in bronchoalveolar lavage cells and bronchial biopsies derived from smokers (n = 8) and nonsmokers (n = 10). We also investigated gene expression of nuclear transcription factors known to be involved in the regulation of xenobiotic metabolism enzymes. RESULTS: Gene expression of CYP1A1, CYP1B1, CYP2S1, GSTP1, and EPHX1 was induced in bronchoalveolar lavage cells of smokers, whereas expression of CYP2B6/7, CYP3A5, and UGT2A1 was repressed. In bronchial biopsies of smokers, CYP1A1, CYP1B1, CYP2C9, GSTP1, and GSTA2 were induced, but CYP2J2 and EPHX1 were repressed. Induction of CYP1A1 and CYP1B1 transcript abundance resulted in increased activity of the coded enzyme. Finally, expression of the liver X receptor and the glucocorticoid receptor was significantly up-regulated in bronchoalveolar lavage cells of smokers. CONCLUSIONS: We found gene expression of pulmonary xenobiotic metabolizing enzymes and certain key transcription factors to be regulated in bronchoalveolar lavage cells and bronchial biopsies of smokers. The observed changes demonstrate tissue specificity in xenobiotic metabolism, with likely implications for the metabolic activation of procarcinogens to ultimate carcinogens of tobacco smoke. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Standard drugs post-myocardial infarction (MI) such as angiotensin converting enzyme (ACE) and 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) increase levels of endothelial progenitor cells (EPC). However, potential underlying mechanisms have not yet been investigated. Methods and results: We studied the effects of ACE inhibition or statin treatment on EPC levels and on bone marrow molecular pathways involved in EPC mobilization after MI in rats. Three days post-infarction, acetylated LDL (acLDL)+/Ulex europeus-1 (UEA-1)+/VEGF receptor-2+/eNOS+EPC levels and formation of endothelial colony forming units (CFU) were reduced to 60±12% (p <0.05) and 68±7% (p <0.05). In bone marrow, extracellular signal-regulated kinase (ERK) phosphorylation and matrix metalloproteinase (MMP)-9 activity were repressed. Endothelial nitric oxide synthase (eNOS) activity was unchanged, whereas reactive oxygen species (ROS) were increased two-fold in bone marrow. ACE or HMG-CoA reductase inhibition resulted in significant increases in EPC levels. ACE inhibition increased bone marrow ERK phosphorylation and MMP-9 activity. Statin therapy enhanced bone marrow VEGF protein levels, Akt phosphorylation, eNOS activity and normalized increased ROS levels. Augmented EPC levels in the early post-infarction phase by ACE inhibition or statin treatment were associated with improved cardiac function and increased capillary density in the peri-infarct area 7 days after MI. Moreover, increased EPC levels in response to ACE inhibition or statin treatment were sustained 10 weeks post-infarction. Conclusions: Increased ROS and impaired MMP-9 activity in bone marrow likely contribute to reduced EPC mobilization in the early post-infarction phase. ACE inhibition or statin treatment increased EPC levels with distinct drug-specific effects on bone marrow molecular alterations. [Copyright &y& Elsevier]

The first evidence for a role of growth hormone (GH) in endothelial biology came from studies of growth-hormone-deficient patients, who are at increased cardiovascular risk. GH replacement therapy improves cardiovascular outcome in these patients. Underlying mechanisms include normalization of a disturbed balance of vascular nitric oxide (NO) and reactive oxygen species, as well as modulation of extracellular matrix proteins. In this short report we review what is known from bench and bedside about GH-mediated regulation of vascular function. Novel findings suggest Janus kinase-signal transducer and activator of transcription (JAK-STAT) and Akt pathways to be involved in GH-mediated activation of the endothelial NO synthase. [ABSTRACT FROM AUTHOR]

Stem cell transplantation after myocardial infarction has been claimed to restore cardiac function, but the underlying mechanism remains unclear. A minority of transplanted cells become adherent in heart tissue and contribute to neovascularization, whereas many donor cells die from apoptosis. We propose that apoptosis of transplanted cells modulates local tissue reactions. Apoptotic cells impact on immune reactivity by down-regulating innate and adaptive immunity, deactivating macrophages and dendritic cells, and stimulating regulatory T cells. This leads to reduced scar formation, repressed myocardial apoptosis, and improved cardiac outcome. [Copyright &y& Elsevier]

Objectives: We tested the hypothesis that asymmetric dimethylarginine (ADMA) may be an endogenous inhibitor of endothelial progenitor cells (EPCs). Background: Endothelial progenitor cells play a pivotal role in regeneration of injured endothelium, thereby limiting the formation of atherosclerotic lesions. Reduced numbers of EPCs may affect progression of coronary artery disease. Regulation of EPC mobilization and function is mediated in part by nitric oxide (NO). Endogenous inhibitors of NO synthases, such as ADMA, contribute to endothelial dysfunction and injury. Methods: We used flow cytometry and in vitro assays to investigate the relationship between EPC number and function with ADMA plasma levels in patients with stable angina. Results: The plasma concentration of ADMA was related to the severity of coronary artery disease and correlated inversely with the number of circulating CD34+/CD133+ progenitor cells (r = −0.69; p < 0.0001) and endothelial colony forming units (CFUs) (r = −0.75; p < 0.0001). Adjusting for all patient characteristics, we confirmed these findings in multivariate regression analyses. In vitro differentiation of EPCs was repressed by ADMA in a concentration-dependent manner. Compared with untreated cells, ADMA reduced EPC incorporation into endothelial tube-like structures to 27 ± 11% (p < 0.001). Asymmetric dimethylarginine repressed the formation of CFUs from cultured peripheral blood mononuclear cells to 35 ± 7% (p < 0.001). Asymmetric dimethylarginine decreased endothelial nitric oxide synthase activity in EPCs to 64 ± 6% (p < 0.05) when compared with controls. Co-incubation with the hydroxymethyl glutaryl coenzyme A reductase inhibitor rosuvastatin abolished the detrimental effects of ADMA. Conclusions: Asymmetric dimethylarginine is an endogenous inhibitor of mobilization, differentiation, and function of EPCs. This contributes to the cardiovascular risk in patients with high ADMA levels and may explain low numbers and function of EPCs in patients with coronary artery disease. [Copyright &y& Elsevier]

Endothelial progenitor cells (EPCs) are bone-marrow-derived cells that enter the systemic circulation to replace defective or injured mature endothelial cells. EPCs also contribute to neovascularization and limit the progression of atherosclerosis. Patients with reduced EPC levels or dysfunctional EPCs are at increased risk for coronary artery disease. Drug-mediated improvement of the mobilization, differentiation, function and homing of EPCs to sites of ischemia or injured endothelium may therefore be a promising novel therapeutic approach for various cardiovascular diseases. On the other hand, endogenous inhibitors of EPCs could also be valuable drug targets. The identification of EPC inhibitors and the development of novel drugs that can efficiently regulate production or elimination of these molecules may also be a promising approach for the future treatment of atherosclerosis. In the present review we summarize potential endogenous and exogenous inhibitors of EPCs, such as oxidized low-density lipoproteins, angiotensin II, glucose, cigarette smoke and others. Whenever possible, we also describe the underlying molecular events. Drug-induced mobilization and improvement of EPC function, as well as reduction of EPC inhibitors, is likely to enhance endothelial function and reduce atherosclerotic processes. [ABSTRACT FROM AUTHOR]

Growth hormone deficiency is linked to cardiovascular disease and particularly increased peripheral vascular resistance. Surprisingly, its role in endothelial nitric oxide (NO) synthetase (eNOS) regulation and NO release is basically unknown. We therefore studied the effects of different doses of somatotropin in cultures of a human endothelial cell line (EAhy926). We investigated expression and activity of eNOS, as well as other target genes known to be deregulated in cardiovascular disease including E-selectin and the lectin-like oxidized low density lipoprotein receptor. Treatment of cultured human endothelial cells with somatotropin resulted in significant (P<0.05) increases of eNOS gene and protein expression, as well as NO release, whereas production of intracellular reactive oxygen species was significantly reduced, at the highest somatotropin dose level. The enhanced eNOS gene/protein expression and enzyme activity correlate well. Our findings are suggestive for a novel role of growth hormone in endothelial biology, and particularly NO production. [Copyright &y& Elsevier]

Focuses on a study which observed coregulation of ion channels and the androgen receptor, and proposed a role for the receptor in ion channel regulation. Way in which electrical conductance is altered; Role played by the hierarchical gene cluster analysis; Factors that repressed cardiac gene expression.

Verapamil is a commonly prescribed cardiovascular drug, but surprisingly its metabolism in the target tissue of pharmacotherapy is basically unknown. We therefore investigated its biotransformation in human heart tissue and correlate the production of metabolites with the gene expression of major drug metabolising enzymes. Using electrospray LC–MS–MS and LC–MS3 experiments, a total of nine metabolites were observed in incubation experiments with verapamil and microsomes isolated from the human heart tissue, and this included a carbinolamine-, N-formyl-, ahemiacetale-, and formate-intermediate of N-demethyl- and O-demethylverapamil. We also observed a hydroxylation product at the benzylic position of atom C-7 (M9). Metabolites M5–M9 are novel and were not observed in previous studies with liver or other human tissues. A fine example of the considerable metabolic competence of human heart is the formation of M1–M4, e.g. dealkylverapamil, norverapamil and isomers of O-demethylverapamil, which were believed to be exclusively produced by the liver. [Copyright &y& Elsevier]

SummaryBackground: Cytochrome P450 mono-oxygenases bring about metabolism of many drugs, including verapamil, but no information is available on the metabolism of such drugs in the human heart.Methods: We investigated the gene expression of major human cytochrome P450 mono-oxygenases in the various regions of explanted hearts from six patients with dilated cardiomyopathy and one with transposition of the arterial trunk. For comparison we also studied samples of liver and lung from three patients and two samples of normal heart. The biological significance of tissue-specific cytochrome mono-oxygenase gene expression was further investigated by study of the microsomal metabolism of verapamil in ventricular tissue.Findings: mRNA for the cytochromes 1A1, 2B6/7, 2C8-19, 2D6, and 4B1 was predominantly expressed in the right ventricle; the unilateral expression of the 2D6 gene in right- venticular tissue is important because of its key role in the metabolism of Beta-blockers. A strong correlation between tissue-specific gene expression and enzyme activity was found; microsomal metabolism of verapamil was confined to the right ventricle. By contrast, cytochrome P450 3A genes (which are the major drug-metabolising enzymes in the liver and the lung) were not expressed in any of the human heart tissues, and mRNA transcripts for epoxide hydrolase, cytochrome P450 2E1, and flavin-containing mono-oxygenases 2 and 5 were detected in all regions of the human heart and the great vessels.Interpretation: These findings show that expression of genes for cytochrome P450 mono-oxygenases and verapamil metabolism are found predominantly in the right side of the heart. This finding may explain lack of efficacy of certain cardioselective drugs. [ABSTRACT FROM AUTHOR]

The development of hydrogels based on dextrans, pullulan and lentinan to be used in biomedical applications including tissue engineering is reported. Despite the fact that selected polysaccharides such as hyaluronic acid are well established, little is known, how these polysaccharides can be chemically modified to create hydrogels under controlled conditions. In this study we present a small library of chemically modified polysaccharides which are used for a divergent approach to achieve biomedical relevant hydrogels. In this case the crosslinking is based on thio ether formation between thiol modified donor and vinylsulfone or maleimide modified acceptor components. Successful synthesis of the linker systems and coupling at the polysaccharides, hydrogel formation takes place under physiological conditions. We extended the study by coupling small molecules like adhesion factors for increasing cell compatibility as well as a dye for further studies. The different hydrogels were studied to their rheological properties, water uptake, their permeability, biodegrability and their cytotoxicity. [ABSTRACT FROM AUTHOR]

• Fibrosis is a common trait of cardiomyopathies reflecting shared pathogenesis. • Abnormal extracellular matrix remodeling is linked to fibrosis in cardiomyopathies. • The diversity of cardiomyopathies requires novel tools for diagnosis and treatment. • Extracellular matrix can serve as a source of novel biomarkers and drug targets. • Multidisciplinary approaches show potential in improving cardiomyopathy management. Cardiomyopathies encompass a spectrum of heart disorders with diverse causes and presentations. Fibrosis stands out as a shared hallmark among various cardiomyopathies, reflecting a common thread in their pathogenesis. This prevalent fibrotic response is intricately linked to the consequences of dysregulated extracellular matrix (ECM) remodeling, emphasizing its significance in the development and progression the disease. This review explores the ECM involvement in various cardiomyopathies and its impact on myocardial stiffness and fibrosis. Additionally, we discuss the potential of ECM fragments as early diagnosis, prognosis, and risk stratification. Biomarkers deriving from turnover of collagens and other ECM proteins hold promise in clinical applications. We outline current clinical management, future directions, and the potential for personalized ECM-targeted therapies with specific focus on microRNAs. In summary, this review examines the role of the fibrosis in cardiomyopathies, highlighting the potential of ECM-derived biomarkers in improving disease management with implications for precision medicine. [ABSTRACT FROM AUTHOR]

To evaluate the prognostic value of eleven microRNAs (miRNAs) compared to high-sensitivity Troponin T (hs-cTnT) in patients presenting with suspected acute coronary syndrome (ACS) to the emergency department (ED). 1,042 patients presenting between August 2014 and April 2017 were included. Expression levels of eleven microRNAs (miR-21-5p, miR-22-3p, miR-29a-3p, miR-92a-3p, miR-122-5p, miR-126-3p, miR-132-3p, miR-133a-3p, miR-134-5p, miR-191-3p, and miR-423-5p) were determined using RT-qPCR. All-cause mortality (ACM) and a composite of ACM, acute myocardial infarction (AMI) and stroke were defined as endpoints. During a median follow-up of 399 (P25-P75: 381–525) days 58 patients (5.6%) died. The composite endpoint occurred in 86 patients (8.3%). Different expression levels of miR-21-5p (median, P25-P75: 5.28 [5.14–5.51] vs. 5.16 [4.97–5.35], p = 0.0033) and miR-122-5p (median, P25-P75: 5.17 [4.81–5.49] vs. 5.35 [5.01–5.69], p = 0.0184) were observed in patients who died compared to survivors. ROC-optimized cutoff of miR-21-5p (HR, P25-P75: 3.3 [1.2–9.4], p = 0.0239), but not miR-122-5p (HR, P25-P75: 0.4 [0.2–0.8], p = 0.0116), was predictive for all-cause mortality, even after adjustment in a multivariate model. Nevertheless, addition of miR-21-5p and miR-122-5p decreased prognostic accuracy of hs-cTnT for all-cause mortality (△AUC: 0.112, p = 0.0159). Hs-cTnT admission values had a high prognostic value for ACM (AUC [95%CI] = 0.794 [0.751–0.837]) and the composite of ACM, AMI and stroke (AUC [95%CI] = 0.745 [0.695–0.794]). Despite a different expression depending on outcomes miR-21-5p and miR-122-5p do not add prognostic information to hs-cTnT in patients presenting with suspected ACS to the ED. [ABSTRACT FROM AUTHOR]

The authors discuss the impact of microRnas (miRNAs/miRs) therapeutics in cardiac fibrosis. The authors say that miRNAs has been used as powerful gene expression regulator and in the pathogenesis of various pathological events, such as cardiac fibrosis. They also cite a study by researcher Z. Pan and colleagues which reveals the impact of miR-101 regulation in the treatment of cardiac fibrosis after myocardial infarction (MI).

A letter to the editor is presented in response to an article on the use of erythropoietin in type 2 diabetes and kidney disease by S. D. Solomon in the September 16, 2010 issue.

The article examines the effectiveness regarding the use of insulin-like growth factor-1 (IGF-1) receptor as a therapeutic target to improve the function of endothelial progenitor cells (EPC). It discusses the potent angiogenic paracrine effects of EPC. The study found that the activation of IGF-1 increases overall nitric oxide (NO) bioavailability. Other results are discussed.