Anders Waldenström

Randomized trial of insulin-glucose infusion followed by subcutaneous insulin treatment in diabetic patients with acute myocardial infarction (DIGAMI study): Effects on mortality at 1 year

OBJECTIVES We tested how insulin-glucose infusion followed by multidose insulin treatment in diabetic patients with acute myocardial infarction affected mortality during the subsequent 12 months of follow-up. BACKGROUND Despite significant improvements in acute coronary care, diabetic patients with acute myocardial infarction still have a high mortality rate. METHODS A total of 620 patients were studied: 306 randomized to treatment with insulin-glucose infusion followed by multidose subcutaneous insulin for > or = 3 months and 314 to conventional therapy. RESULTS The two groups were well matched for baseline characteristics. Blood glucose decreased from 15.4 +/- 4.1 to 9.6 +/- 3.3 mmol/liter (mean +/- SD) in the infusion group during the 1st 24 h, and from 15.7 +/- 4.2 to 11.7 +/- 4.1 among control patients (p < 0.0001). After 1 year 57 subjects (18.6%) in the infusion group and 82 (26.1%) in the control group had died (relative mortality reduction 29%, p = 0.027). The mortality reduction was particularly evident in patients who had a low cardiovascular risk profile and no previous insulin treatment (3-month mortality rate 6.5% in the infusion group vs. 13.5% in the control group [relative reduction 52%, p = 0.046]; 1-year mortality rate 8.6% in the infusion group vs. 18.0% in the control group [relative reduction 52%, p = 0.020]). CONCLUSIONS Insulin-glucose infusion followed by a multidose insulin regimen improved long-term prognosis in diabetic patients with acute myocardial infarction.

Targeted Anticytokine Therapy in Patients With Chronic Heart Failure Results of the Randomized Etanercept Worldwide Evaluation (RENEWAL)

Background—Studies in experimental models and preliminary clinical experience suggested a possible therapeutic role for the soluble tumor necrosis factor antagonist etanercept in heart failure. Methods and Results—Patients with New York Heart Association class II to IV chronic heart failure and a left ventricular ejection fraction ≤0.30 were enrolled in 2 clinical trials that differed only in the doses of etanercept used. In RECOVER, patients received placebo (n=373) or subcutaneous etanercept in doses of 25 mg every week (n=375) or 25 mg twice per week (n=375). In RENAISSANCE, patients received placebo (n=309), etanercept 25 mg twice per week (n=308), or etanercept 25 mg 3 times per week (n=308). The primary end point of each individual trial was clinical status at 24 weeks. Analysis of the effect of the 2 higher doses of etanercept on the combined outcome of death or hospitalization due to chronic heart failure from the 2 studies was also planned (RENEWAL). On the basis of prespecified stopping rules, both trials were terminated prematurely owing to lack of benefit. Etanercept had no effect on clinical status in RENAISSANCE (P =0.17) or RECOVER (P =0.34) and had no effect on the death or chronic heart failure hospitalization end point in RENEWAL (etanercept to placebo relative risk=1.1, 95% CI 0.91 to 1.33, P =0.33). Conclusions—The results of RENEWAL rule out a clinically relevant benefit of etanercept on the rate of death or hospitalization due to chronic heart failure.

Atlas of the clinical genetics of human dilated cardiomyopathy

AIM Numerous genes are known to cause dilated cardiomyopathy (DCM). However, until now technological limitations have hindered elucidation of the contribution of all clinically relevant disease genes to DCM phenotypes in larger cohorts. We now utilized next-generation sequencing to overcome these limitations and screened all DCM disease genes in a large cohort. METHODS AND RESULTS In this multi-centre, multi-national study, we have enrolled 639 patients with sporadic or familial DCM. To all samples, we applied a standardized protocol for ultra-high coverage next-generation sequencing of 84 genes, leading to 99.1% coverage of the target region with at least 50-fold and a mean read depth of 2415. In this well characterized cohort, we find the highest number of known cardiomyopathy mutations in plakophilin-2, myosin-binding protein C-3, and desmoplakin. When we include yet unknown but predicted disease variants, we find titin, plakophilin-2, myosin-binding protein-C 3, desmoplakin, ryanodine receptor 2, desmocollin-2, desmoglein-2, and SCN5A variants among the most commonly mutated genes. The overlap between DCM, hypertrophic cardiomyopathy (HCM), and channelopathy causing mutations is considerably high. Of note, we find that >38% of patients have compound or combined mutations and 12.8% have three or even more mutations. When comparing patients recruited in the eight participating European countries we find remarkably little differences in mutation frequencies and affected genes. CONCLUSION This is to our knowledge, the first study that comprehensively investigated the genetics of DCM in a large-scale cohort and across a broad gene panel of the known DCM genes. Our results underline the high analytical quality and feasibility of Next-Generation Sequencing in clinical genetic diagnostics and provide a sound database of the genetic causes of DCM.

Cardiomyocyte microvesicles contain DNA/RNA and convey biological messages to target cells.

Background Shedding microvesicles are membrane released vesicles derived directly from the plasma membrane. Exosomes are released membrane vesicles of late endosomal origin that share structural and biochemical characteristics with prostasomes. Microvesicles/exosomes can mediate messages between cells and affect various cell-related processes in their target cells. We describe newly detected microvesicles/exosomes from cardiomyocytes and depict some of their biological functions. Methodology/Principal Findings Microvesicles/exosomes from media of cultured cardiomyocytes derived from adult mouse heart were isolated by differential centrifugation including preparative ultracentrifugation and identified by transmission electron microscopy and flow cytometry. They were surrounded by a bilayered membrane and flow cytometry revealed presence of both caveolin-3 and flotillin-1 while clathrin and annexin-2 were not detected. Microvesicle/exosome mRNA was identified and out of 1520 detected mRNA, 423 could be directly connected in a biological network. Furthermore, by a specific technique involving TDT polymerase, 343 different chromosomal DNA sequences were identified in the microvesicles/exosomes. Microvesicle/exosomal DNA transfer was possible into target fibroblasts, where exosomes stained for DNA were seen in the fibroblast cytosol and even in the nuclei. The gene expression was affected in fibroblasts transfected by microvesicles/exosomes and among 333 gene expression changes there were 175 upregulations and 158 downregulations compared with controls. Conclusions/Significance Our study suggests that microvesicles/exosomes released from cardiomyocytes, where we propose that exosomes derived from cardiomyocytes could be denoted “cardiosomes”, can be involved in a metabolic course of events in target cells by facilitating an array of metabolism-related processes including gene expression changes.

A genome-wide association study identifies two loci associated with heart failure due to dilated cardiomyopathy

AIMS Dilated cardiomyopathy (DCM) is a major cause of heart failure with a high familial recurrence risk. So far, the genetics of DCM remains largely unresolved. We conducted the first genome-wide association study (GWAS) to identify loci contributing to sporadic DCM. METHODS AND RESULTS One thousand one hundred and seventy-nine DCM patients and 1108 controls contributed to the discovery phase. Pools of DNA stratified on disease status, population, age, and gender were constituted and used for testing association of DCM with 517 382 single nucleotide polymorphisms (SNPs). Three DCM-associated SNPs were confirmed by individual genotyping (P < 5.0 10(-7)), and two of them, rs10927875 and rs2234962, were replicated in independent samples (1165 DCM patients and 1302 controls), with P-values of 0.002 and 0.009, respectively. rs10927875 maps to a region on chromosome 1p36.13 which encompasses several genes among which HSPB7 has been formerly suggested to be implicated in DCM. The second identified locus involves rs2234962, a non-synonymous SNP (c.T757C, p. C151R) located within the sequence of BAG3 on chromosome 10q26. To assess whether coding mutations of BAG3 might cause monogenic forms of the disease, we sequenced BAG3 exons in 168 independent index cases diagnosed with familial DCM and identified four truncating and two missense mutations. Each mutation was heterozygous, present in all genotyped relatives affected by the disease and absent in a control group of 347 healthy individuals, strongly suggesting that these mutations are causing the disease. CONCLUSION This GWAS identified two loci involved in sporadic DCM, one of them probably implicates BAG3. Our results show that rare mutations in BAG3 contribute to monogenic forms of the disease, while common variant(s) in the same gene are implicated in sporadic DCM.

New concept in echocardiography: harmonic imaging of tissue without use of contrast agent

BACKGROUND Endocardial border detection is important for echocardiographic assessment of left-ventricular function. Second harmonic imaging of contrast agents enhances this border detection. We discovered that harmonic imaging improves tissue visualisation even before contrast injection. We therefore sought objectively to demonstrate the degree of enhancement of endocardial and myocardial visualisation. METHODS An ATL HDI-3000 scanner with software for contrast harmonic imaging was used to record short-axis images of the left ventricle in 27 patients with possible myocardial disease and 22 controls, in the fundamental mode and with harmonic imaging. A computer program measured the relative grey-scale values within six segments of the endocardium and myocardium. An Acuson Sequoia scanner equipped with software for tissue harmonic imaging was used to investigate the reproducibility of ejection-fraction calculations in 22 patients with ischaemic heart disease. FINDINGS Harmonic imaging produced brighter endocardium within each segment. Relative to the mean grey value of the total imaging sector, the values for harmonic and fundamental imaging were 171.5 vs 85.6% (p<0.0001) in end diastole and 194.1 vs 106.7% (p<0.0001) in end systole. Results for the myocardial segments were also significantly better for harmonic imaging. Structure enhancement of similar magnitude was seen among patients and healthy controls. Use of harmonic imaging reduced the proportion of unacceptable images by 14-46% in different views and improved the reproducibility of biplane ejection-fraction measurements. INTERPRETATION In comparison with fundamental imaging, the relative endocardial and myocardial brightness is enhanced by harmonic imaging.

A possible role of noradrenaline in the development of myocardial infarction: An experimental study in the isolated rat heart

Isolated rat hearts were perfused with buffer containing noradrenaline 10(-7) to 10(-4) M. A dose-dependent depletion of glycogen and ATP were seen together with a leakage of ASAT and creatine phosphokinase (CK). The damage induced by noradrenaline could be prevented by addition of a beta-blocker (metoprolol), verapamil, or lidocaine to the perfusion medium. When the endogenous myocardial stores of noradrenaline are rapidly depleted by perfusion with tyramine a similar cell damage was demonstrated. Electron micrographs from hearts subjected to noradrenaline showed three different types of cell damage that could be correlated to earlier described findings. The importance of noradrenaline for the ischemic injury was demonstrated. It was hypothesized that acute myocardial infarction may start because of a sudden release of endogenous noradrenaline.

Mortality prediction in diabetic patients with myocardial infarction: experiences from the DIGAMI study.

OBJECTIVES We analysed predictors of 1-year mortality following acute myocardial infarction in patients with diabetes mellitus by applying uni- and multivariate statistics on the DIGAMI cohort. BACKGROUND Diabetic patients with acute myocardial infarction have a poor prognosis. This may depend on a poor metabolic control, a hypothesis that was tested in DIGAMI, a prospective randomised study. In this trial institution of immediate intensive insulin treatment reduced 1-year mortality by 30%. METHODS We recruited 620 diabetic patients with acute myocardial infarction, 314 of whom served as controls, while the remaining 306 patients were treated with an acute insulin-glucose infusion followed by multidose subcutaneous insulin. RESULTS Age, previous myocardial damage, duration of the diabetes and previous insulin therapy were significantly related to 1-year mortality, while conventional risk factors lacked independent prognostic weight. Female sex was not linked to mortality when controlling for the confounding effects of other predictors. One of the strongest predictors of a fatal outcome, in particular during the hospital phase, was blood glucose at hospital admission. Beta-blockade appeared to exert a striking, independent secondary-preventive effect. CONCLUSIONS It seems that good metabolic control and not conventional risk factors is of major importance for diabetic patients sustaining acute myocardial infarction. Also treatment with beta-blockade seems to be of special importance in this category of patients.

Regional and Global Right Ventricular Function in Healthy Individuals Aged 20–90 Years: A Pulsed Doppler Tissue Imaging Study Umeå General Population Heart Study

The aim of the present study was to describe regional and global right ventricular (RV) function in a wide age range of healthy subjects of both sexes. We studied 255 (125 females) healthy individuals randomly selected from the Umeå General Population Register, age 58 ± 19 (range 22–89) years. RV function was studied using myocardial tissue Doppler imaging of the RV free wall. Isovolumic contraction (IVCv), systolic (Sv), early (Ev), and late (Av) diastolic velocities were measured. Furthermore, isovolumic periods and ejection time intervals were also measured. Conventional Doppler was used to study RV global filling properties. While systolic myocardial velocities were conserved over age, there was a decrease in myocardial E/A ratio with increasing age (r =−0.67, P < 0.001, for base) taken from the RV free wall. A similar age relation was found in RV global filling velocities with a reduced tricuspid E/A ratio (r =−0.57, P < 0.001). Furthermore, a significant correlation was found between global and regional E/A ratios at the basal (r = 0.58, P ≤ 0.001) and mid‐segmental levels (r = 0.46, P ≤ 0.001). Systolic myocardial velocities behaved independent of age whereas regional as well as global E/A ratio were age‐related. No relationship was found between regional isovolumic time intervals and age. Knowledge of these age‐dependent relationships is fundamental when evaluating RV function in patients.

Correlation between increased nitric oxide production and markers of endothelial activation in systemic sclerosis: Findings with the soluble adhesion molecules E‐selectin, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1

OBJECTIVE To determine the relationship between vascular function and the inflammatory response in systemic sclerosis (SSc), and to investigate whether production of endothelial-derived nitric oxide (NO) is disturbed in this disease. METHODS We measured plasma nitrate, urinary excretion of both nitrate and cGMP, and soluble adhesion molecules of endothelial origin in patients with SSc and in age- and sex-matched controls and compared these levels between groups. Additionally, we performed correlation analysis to determine how these variables were related to one another. Plasma nitrate and 24-hour-urinary excretion of nitrate in patients and controls were measured after a 72-hour nitrate-free-diet, using a gas chromatography/mass spectrometric method. Soluble adhesion molecules intercellular adhesion molecule 1 (sICAM-1), vascular cell adhesion molecule 1 (sVCAM-1), and E-selectin and cytokines were measured by enzyme-linked immunosorbent assay. The expression of E-selectin was further investigated in skin biopsy specimens by immunoperoxidase staining, and the presence of inducible NO synthase by immunoblotting. RESULTS Plasma nitrate and 24-hour-urinary-excretion of cGMP were significantly elevated in patients compared with controls, while 24-hour-urinary-excretion of nitrate tended to be elevated in SSc patients. Levels of sICAM-1, sVCAM-1, and sE-selectin were significantly elevated in the patients. Levels of plasma nitrate in the patients correlated significantly with levels of sVCAM-1 (P = 0.020) and sE-selectin (P = 0.018) and approached a significant correlation with sICAM-1 (P = 0.055), suggesting that activated endothelial cells may produce plasma nitrate. CONCLUSION NO synthesis is elevated in SSc patients, and the activated endothelial cell is a likely site of its production.