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Background: A link between diabetes mellitus (DM) and heart failure (HF) has been well-recognized for more than a century. HF is also closely linked to abnormal glucose regulation (AGR) and insulin resistance (IR) in patients without DM and, similarly, these conditions commonly coexist. In epidemiological studies, each condition appears to predict the other. The prevalence of AGR/IR in HF patients without DM is significantly underrecognized and, as yet, the optimal method for screening for these abnormalities in the outpatient setting is unclear.Methods and Results: The purpose of this review is to overview the prevalence and prognostic impact of AGR and IR in HF patients without DM and discuss potential pathophysiological pathways that link these conditions with HF. The severity of glucose intolerance in patients with HF correlates with functional and clinical severity of HF and is an independent predictor of an adverse outcome. It is thought that changes in cardiac metabolism, including a switch from glucose metabolism toward fatty acid metabolism, may in part contribute to the pathophysiological processes associated with HF patients with AGR/IR.Conclusions: We discuss how pharmacological targeting of metabolic pathways in the myocardium of these patients with HF may represent novel therapeutic strategies in these at-risk patients. [ABSTRACT FROM AUTHOR]

Cardiac hypertrophy, one of the major risk factors in hypertension, is associated with a high incidence of congestive heart failure and sudden death. Despite efforts over the last 20 years, the underlying molecular mechanisims of cardiac hypertrophy are still poorly understood, thus making it difficult to develop new therapeutic strategies. A growing body of evidence suggests that cardiac hypertrophy results from mechanical stress that triggers paracrine and autocrine signal transduction pathways. Furthermore, whereas hypertrophy leads to isoform switches in some contractile proteins, increased protein synthesis is largely based on increased translational capacity. Cardiac growth under physiological as well as pathological conditions is regulated by several recently identified transcription factors. Among the factors that are capable of transmitting hypertrophic stimuli to the nucleus is the early growth response gene-1 (Egr-1). Whereas female gender is already an established cardioprotective factor in clinical trials, some very recent data indicate that oestrogens and the nuclear oestrogen receptor may directly modulate gene expression in the development of cardiac hypertrophy. Future pharmacological interventions could be directed towards modifying the nuclear signal transduction cascade involving multiple protein kinases and phosphatases. [ABSTRACT FROM PUBLISHER]

Cardiac hypertrophy is characterized by growth of myocardial cells without proliferation. Many endo- paracrine stimuli such as angiotensin II, endothelin, aradrenergic agonists, and insulin have been shown to be able to induce cardiac hypertrophy either in vivo or in vitro. We have used the myoblast model of differentiation and proliferation to determine nuclear signal transduction mechanisms in muscle and (by analogy) cardiac growth. The first nuclear event known to occur when a growth stimulus acts upon a cell is induction of a family of immediate-early genes. Our group focused on the role of one of these genes, the early growth response gene-1 (Egr-1). We have shown that this gene is induced in isolated adult cardiac myocytes in the presence of endothelin. An anti-sense oligonucleotide complementary to the first six codons of the Egr-1 mRNA abolishes the stimulation of protein synthesis induced by endothelin. In the present study we further characterized paracrine growth stimuli in the myogenic cell line Sol8, which was used as a paradigm to further investigate mechanisms of paracrine growth induction. We demonstrated that a variety of candidate endo- paracrine stimuli for the induction of cardiac hypertrophy induced the Egr-1 messenger RNA in the myogenic cell line Sol8. Among these are endothelin, insulin, basic fibroblast growth factor, and platelet-derived growth factor BB (PDGE BB). We conclude: (1) In analogy to the myocardium, these growth factors act upon myoblasts. (2) This line appears to be a suitable model for the molecular characterization of Egr-1 target genes. [ABSTRACT FROM PUBLISHER]

AIMS: To determine whether junctional sequences of rearranged chromosomes can be amplified by use of the polymerase chain reaction (PCR) and whether direct sequence analysis of the PCR products is possible, using DNA from formalin fixed, paraffin wax embedded biopsy specimens. METHODS: DNA was extracted from paraffin wax embedded, formalin fixed lymphoma specimens, and junctional sequences of rearranged chromosomes were amplified by the PCR. The products were used as templates for asymmetrical PCR. Subsequently, direct sequence analysis was performed using the chain termination method. RESULTS: Formalin fixed, paraffin wax embedded biopsy specimens and PCR amplification could be used to determine the nucleotide sequences of junctional regions of rearranged chromosomes t(14;18) from patients with follicular lymphoma. CONCLUSION: The identification of junctional sequences of the translocation in follicular lymphoma provides a molecular "fingerprint" of t(14;18) of the lymphoma of an individual patient and can be used for the detection of clone specific DNA in any biopsy tissue obtained from the patient. The strategy used for rapid sequence analysis of PCR amplified DNA sequences will be useful in many areas of molecular pathology. [ABSTRACT FROM PUBLISHER]

Purpose: Transverse aortic constriction (TAC) has been extensively used as a cardiac stress in genetically modified mice to investigate the molecular mechanisms of cardiac hypertrophy. But the hypertrophic response to TAC can be significantly influenced by the time course of TAC, the age and the genetic background of the mice. The International Knockout Mouse Consortium has selected to use the C57BL/6NTac mouse strain to generate null alleles for all mouse genes; however, we have found a range of baseline cardiac phenotypic differences between this substrain and the commonly used C57BL/6J substrain. Therefore, we have assessed the optimal conditions to induce cardiac hypertrophy by TAC in the C57BL/6NTac strain, and have determined whether the hypertrophic response to TAC is different in these two C57BL/6 substrains.Methods: To establish the optimal conditions for TAC-induced hypertrophy in the C57BL/6NTac substrain, 8, 10 and 12-week old mice were subjected to TAC and monitored by echocardiography. Cardiac function was found to significantly deteriorate in 10-12 week old mice after 2 weeks, while 8-week old mice developed hypertrophy after 2 weeks and then reduced cardiac function after 5 weeks. Therefore, 2-week TAC in 8 week old mice was used to further study the hypertrophic response in the two C57BL/6 substrains. Echocardiography, conscious ECG, cardiac haemodynamic assessment, histology, and real-time PCR were conducted to evaluate cardiac function, hypertrophy, fibrosis, and the expression of hypertrophy markers.Results: Cardiac hypertrophy evaluated by heart weight to tibia length ratio (HW/TL) was highly variable in C57BL/6J mice, but this reflected the variation in aortic arch dimension as assessed by echocardiography. When comparing the response to the hypertrophic stimulus, C57BL/6NTac demonstrated greater hypertrophic growth as evaluated by HW/TL, cardiomyocyte cell surface area, and expression of BNP (all p<0.05). Cardiac remodelling such as fibrosis was also more extensive. This exacerbated hypertrophic growth was associated with increased QRS duration (19.33±2.76 vs. 15.29±0.64 ms, p=0.01), QTc interval and multiple ventricular arrhythmias in C57BL/6NTac mice.Conclusion: There are clear differences in the response to pressure overload in widely used C57BL/6 substrains. C57BL/6J mice were found to have a large variation in aortic structure which is reflected in the variable hypertrophic response; whilst the C57BL/6NTac substrain has a consistently exacerbated hypertrophic response. It is therefore essential to consider these distinct phenotypic differences when interpreting data. [ABSTRACT FROM AUTHOR]

Heart failure is often associated with renal impairment (cardiorenal syndrome). Using a metabolomics approach, our group identified α-ketoglutarate as a novel metabolite that was significantly elevated in patients with heart failure. It was as strongly associated with heart failure as the 'gold-standard-tm) biomarker brain natriuretic peptide. α-Ketoglutarate is a citric acid cycle intermediate, central in cardiac energy production. It is the ligand of GPR99, a G-protein coupled receptor mostly expressed in the kidney. In HEK 293 cells, GPR99 acted through a Gq-mediated pathway to increase intracellular calcium. Importantly, we found that the GPR99 receptor is present in neonatal rat cardiomyocytes (NRCM). We tested the expression of 84 genes previously known as regulators of angiogenesis in NRCM treated with 1 mM α-ketoglutarate. Using real-time PCR, we found significant increase in the expression of VEGF receptor-1 and placental growth factor, suggesting a possible effect of α-ketoglutarate in the regulation of angiogenesis and growth. These findings show that binding of α-ketoglutarate to the GPR99 receptor in the heart leads to activation of the Gq pathway and causes upregulation of VEGFR1 and placental growth factor. This might have a role in vascular adaptation to hypertrophy. In addition, in vivo animal studies have previously shown that protein kinase C has a role in renal dysfunction. This leads to the novel and testable hypothesis that α-ketoglutarate also contributes to the development of the cardiorenal syndrome. [ABSTRACT FROM AUTHOR]

Cardiac metabolism and cardiac function are inextricably linked, with changes in cardiac metabolism during cardiac ischaemia contributing to the development of cardiac arrhythmias. Using metabolomics, we aim to identify metabolite changes occurring during cardiac ischaemia through analysis of peripheral serum to reconstruct myocardial metabolic pathways that contribute to the development of cardiac arrhythmias. Peripheral venous samples from 25 patients (and 20 patients in a validation cohort) were analysed in an untargeted fashion using LC-MS following cardiac ischaemia induced by transient coronary artery occlusion during PCI at baseline, 1 and 5 min. Following validation, 99 and 126 metabolite peaks were significantly different at 1 min and 5 min after coronary occlusion compared with baseline (p<0.05). Predominantly metabolic pathways involving lipids were perturbed with changes in diacylglycerols (DG), lysophophatidylcholines (LPC), phosphatidylcholine (PC) and free fatty acids (FFA). Myocardial metabolic pathways involving the synthesis of PC from DG and their subsequent breakdown by phospholipase A2 into LPC and FFA such as arachidonic acid (AA) stimulating the oxidation of adrenaline to form the arrhythmogenic metabolite adrenochrome were reconstructed. We are able to reconstruct metabolic pathways involving lipid metabolism within the myocardium during cardiac ischaemia through analysis of the peripheral serum using metabolomics. Our unbiased approach has identified metabolic pathways involved in the production and release of metabolites with pro-arrhythmic properties (AA, LPC and adrenochrome) and metabolites with anti-arrhythmic properties (omega-3 fatty acids: eicosapentaenoic and docosahexanoic acid). This suggests that arrhythmogenesis may be a delicate balance between the endogenous formation of pro-arrhythmic and anti-arrhythmic metabolites. [ABSTRACT FROM AUTHOR]