S. Bergmann

Acute atrial tachyarrhythmia induces angiotensin II type 1 receptor-mediated oxidative stress and microvascular flow abnormalities in the ventricles.

Aims Patients with paroxysmal atrial fibrillation (AF) often present with typical angina pectoris and mildly elevated levels of cardiac troponin (non ST-segment elevation myocardial infarction) during an arrhythmic event. However, in a large proportion of these patients, significant coronary artery disease is excluded by coronary angiography. Here we explored the potential underlying mechanism of these events. Methods and results A total of 14 pigs were studied using a closed chest, rapid atrial pacing (RAP) model. In five pigs RAP was performed for 7 h (600 b.p.m.; n = 5), in five animals RAP was performed in the presence of angiotensin-II type-1-receptor (AT1-receptor) inhibitor irbesartan (RAP+Irb), and four pigs were instrumented without intervention (Sham). One-factor analysis of variance was performed to assess differences between and within the three groups. Simultaneous measurements of fractional flow reserve (FFR) and coronary flow reserve (CFR) before, during, and after RAP demonstrated unchanged FFR (P = 0.327), but decreased CFR during RAP (RAP: 67.7 ± 7.2%, sham: 97.2 ± 2.8%, RAP+Irb: 93.2 ± 3.3; P = 0.0013) indicating abnormal left ventricular (LV) microcirculation. Alterations in microcirculatory blood flow were accompanied by elevated ventricular expression of NADPH oxidase subunit Nox2 (P = 0.039), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1, P = 0.004), and F2-isoprostane levels (P = 0.008) suggesting RAP-related oxidative stress. Plasma concentrations of cardiac troponin-I (cTn-I) increased in RAP (RAP: 613.3 ± 125.8 pmol/L vs. sham: 82.5 ± 12.5 pmol/L; P = 0.013), whereas protein levels of eNOS and LV function remained unchanged. RAP+Irb prevented the increase of Nox2, LOX-1, and F2-isoprostanes, and abolished the impairment of microvascular blood flow. Conclusion Rapid atrial pacing induces AT1-receptor-mediated oxidative stress in LV myocardium that is accompanied by impaired microvascular blood flow and cTn-I release. These findings provide a plausible mechanism for the frequently observed cTn-I elevation accompanied with typical angina pectoris symptoms in patients with paroxysmal AF and normal (non-stenotic) coronary arteries.

Evaluation of a Diabetes Management System Based on Practice Guidelines, Integrated Care, and Continuous Quality Management in a Federal State of Germany : A population-based approach to health care research

OBJECTIVE—The aim of this study was to evaluate the Saxon Diabetes Management Program (SDMP), which is based on integrated practice guidelines, shared care, and integrated quality management. The SDMP was implemented into diabetes contracts between health insurance providers, general practitioners (GPs), and diabetes specialized practitioners (DSPs) unified in the Saxon association of Statutory Health Insurance Physicians. RESEARCH DESIGN AND METHODS—The evaluation of the SDMP in Germany represents a real-world study by using clinical data collected from participating physicians. Between 2000 and 2002 all DSPs and about 75% of the GPs in Saxony participated. Finally, 291,771 patients were included in the SDMP. Cross-sectional data were evaluated at the beginning of 2000 (group A1) and at the end of 2002 (group A2). A subcohort of 105,204 patients was followed over a period of 3 years (group B). RESULTS—The statewide implementation of the SDMP resulted in a change in therapeutic practice and in better cooperation. The median A1C at the time of referral to DSPs decreased from 8.5 to 7.5%, and so did the overall mean. At the end, 78 and 61% of group B achieved the targets for A1C and blood pressure, respectively, recommended by the guidelines compared with 69 and 50% at baseline. Patients with poorly controlled diabetes benefited the most. Preexisting regional differences were aligned. CONCLUSIONS—Integrated care disease management with practicable integrated quality management including collaboration between GPs and specialist services is a significant innovation in chronic care management and an efficient way to improve diabetes care continuously.

Even moderate cigarette smoking influences the pattern of circulating monocytes and the concentration of sICAM-1

The pattern of circulating monocyte subtypes and the concentration of the soluble intercellular adhesion molecule-1 (ICAM-1) were compared in middle-aged female moderate smokers and lifetime non-smokers. Total leukocyte and monocyte counts were higher in smokers. The pattern of circulating monocytes of smokers was changed toward lower absolute counts of activated (CD16+/CD64+) monocytes and (CD16+/CD14+) monocyte-macrophages and higher counts of nonactivated monocytes. The serum concentration of soluble ICAM-1 was significantly higher in smokers than in non-smokers. It is supposed that even moderate cigarette smoking leads to an activation of the circulating monocytes and their increased adhesion to the endothelium.

HIF-1α is a protective factor in conditional PHD2-deficient mice suffering from severe HIF-2α–induced excessive erythropoiesis

Erythropoiesis must be tightly balanced to guarantee adequate oxygen delivery to all tissues in the body. This process relies predominantly on the hormone erythropoietin (EPO) and its transcription factor hypoxia inducible factor (HIF). Accumulating evidence suggests that oxygen-sensitive prolyl hydroxylases (PHDs) are important regulators of this entire system. Here, we describe a novel mouse line with conditional PHD2 inactivation (cKO P2) in renal EPO producing cells, neurons, and astrocytes that displayed excessive erythrocytosis because of severe overproduction of EPO, exclusively driven by HIF-2α. In contrast, HIF-1α served as a protective factor, ensuring survival of cKO P2 mice with HCT values up to 86%. Using different genetic approaches, we show that simultaneous inactivation of PHD2 and HIF-1α resulted in a drastic PHD3 reduction with consequent overexpression of HIF-2α-related genes, neurodegeneration, and lethality. Taken together, our results demonstrate for the first time that conditional loss of PHD2 in mice leads to HIF-2α-dependent erythrocytosis, whereas HIF-1α protects these mice, providing a platform for developing new treatments of EPO-related disorders, such as anemia.

Effects of an early intervention on perceived stress and diurnal cortisol in pregnant women with elevated stress, anxiety, and depressive symptomatology

The goal of the present investigation was to examine effects of a cognitive-behavioral group intervention for pregnant women with subclinically elevated stress, anxiety and/or depression on perceived stress and salivary cortisol levels. Expectant mothers were recruited in gynaecologist practices. They participated in a screening, a standardized diagnostic interview (Munich-Composite Diagnostic Interview, M-CIDI), and were randomly assigned to an intervention (N = 21) and treatment as usual control group (N = 40). The intervention consisted of a manualized cognitive-behavioral group program for expectant mothers with subclinically elevated stress, depression, and/or anxiety symptoms. Stress questionnaire (prenatal distress (PDQ), perceived stress (PSS)) as well as diurnal salivary cortisol assessment took place at T1 (antenatal, preintervention), at T2 (antenatal, post-intervention) and T3 (3-month postpartum). Subjects that participated in the intervention exhibited a significant post-treatment change in morning cortisol (cortisol awakening response, CAR) in contrast to control subjects, F(8,51) = 2.300, p = 0.047. Intervention participants showed a smaller CAR subsequent to the intervention, displaying a lessened stress reaction. This effect was not observed in the control group. In contrast, we failed in discovering a significant difference between the research groups regarding the cortisol area under curve parameter (AUC) and the applied subjective stress questionnaires. Evaluation results were thus heterogeneous. Nevertheless, intervention effects on the CAR are promising. Our results suggest that a cognitive-behavioral intervention might lead to an improvement in the biological stress response of pregnant women with subclinically elevated stress, anxiety, or depressive symptoms.

Comparison of circulating phagocyte oxidative activity measured by chemiluminescence in whole blood and isolated polymorphonuclear leukocytes

The generation of reactive oxygen species (ROS) was measured by chemiluminescence (CL) in whole blood and isolated polymorphonuclear leukocytes (PMNLs) in 113 subjects. There were no differences in ROS production in males and females, smokers and non-smokers and no age dependency. A significant correlation was found between whole blood CL parameters and between parameters derived from isolated cells, but there was no correlation when these parameters were compared using isolated PMNLs and whole blood. Variations in serum lipid levels did not account for the variability of CL parameters in blood or PMNLs. Both methodologies had the same validity in demonstrating priming of phagocytes. Zymosan-induced CL was more sensitive in detecting distinct functional states of phagocytes than FMLP-induced CL.

Differential effects of lipoprotein apheresis by lipidfiltration or dextran sulfate adsorption on lipidomic profile

OBJECTIVE AND METHODS Acute modification of plasma lipidomic profile was assessed by top-down shotgun profiling on a LTQ Orbitrap hybrid mass spectrometer in 14 patients treated with two different apheresis techniques: plasma lipidfiltration (LF) and whole blood dextran sulfate adsorption (DSA). RESULTS Patients treated with DSA revealed a significantly more pronounced reduction of LDL-cholesterol (LDL-C), a diminished decrease of HDL-cholesterol (HDL-C) and triglycerides (TG), and a similar reduction in lipoprotein (a) (Lp(a)) level. Against the overall tendency of reduction of lipid metabolites of all lipid classes in post-apheresis plasma, independent of apheresis technology applied, a highly significant increase of phosphatidylethanolamines (PE) in response to DSA was observed. CONCLUSION These data indicate that DSA technology may be associated with an activation or damage of blood cells at contact surface which subsequently leads to a massive liberation of cellular and membrane PEs. Pathophysiological consequences, especially with respect to coagulation system and oxidative stress, have to be further elucidated.

Food supply abundant increase of serum selenium concentrations in middle-aged Dresden women between 1990 and 1996

Serum selenium concentration was measured in middle-aged Dresden (East Germany) women in 1990 and 1996. In 1990, the serum concentration of selenium in middle-aged women was higher than in men living under the same environmental conditions (0.98 +/- 0.32 vs 0.82 +/- 0.19 micromol/l). In 1996, the serum concentration of selenium in middle-aged women was significantly higher than in 1990 (1.19 +/- 0.34 micromol/l). This increase seems to be caused by the changed foodstuff supply after the reunification of Germany. Selenium values did not correlate with age, blood pressure or daily energy intake. Moderate smoking and menopausal status did not influence the selenium levels. In 1990, the serum concentration of selenium was the highest in those women who consumed the lowest amounts of carbohydrates or fibers, or who had the highest consumption of meat, fresh fish or potatoes.

Association between systemic oxidative stress and insulin resistance/sensitivity indices – the PREDIAS study

Systemic oxidative stress has been causally related to insulin resistance and the subsequent development of type 2 diabetes mellitus (T2D). We investigated associations between circulating oxidative stress markers and different surrogate indexes of insulin sensitivity/resistance.

Circulating Very-Low-Density Lipoprotein from Subjects with Impaired Glucose Tolerance Accelerates Adrenocortical Cortisol and Aldosterone Synthesis

Apart from their role in cardiovascular homeostasis and immunomodulation, aldosterone and cortisol are also implicated in the pathogenesis of insulin resistance and type 2 diabetes mellitus (T2DM). Furthermore, glycoxidative modifications of lipoproteins are increasingly recognized as an etiological factor for increased cardiovascular morbidity and mortality in prediabetic individuals. The causative relationship between in vivo lipoprotein modifications and steroidogenesis in subjects with impaired glucose tolerance (IGT), however, is not well defined. Therefore, we aimed to investigate the impact of in vivo modified lipoproteins on aldosterone and cortisol release from human adrenocortical H295R cells. Following an oral glucose tolerance test, 20 individuals with normal glucose tolerance (NGT) and 20 IGT subjects were randomly selected from the ongoing PRAEDIAS prevention study in our department. Cells were incubated for 24 h with lipoproteins isolated from NGT and IGT individuals and aldosterone and cortisol release was measured in the supernatants. VLDL induced a greater stimulating effect on adrenocortical aldosterone and cortisol release compared to HDL and LDL. Moreover, IGT-VLDL evoked a significantly higher effect (p<0.05) on hormone release than NGT-VLDL. Incubation of cells with in vitro modified lipoproteins and specific pharmacological inhibitors suggests that VLDL presumably recruits ERK1/2 as one of the downstream effectors of Jak-2. In summary, in vivo modified VLDL are able to promote prediabetic hormonal dysregulation by modulating adrenocortical steroidogenesis via Jak-2-ERK dependent pathway.