ESC Working Group on Myocardial Function Position Paper: how to study the right ventricle in experimental models

The right ventricle has become an increasing focus in cardiovascular research. In this position paper, we give a brief overview of the specific pathophysiological features of the right ventricle, with particular emphasis on functional and molecular modifications as well as therapeutic strategies in chronic overload, highlighting the differences from the left ventricle. Importantly, we put together recommendations on promising topics of research in the field, experimental study design, and functional evaluation of the right ventricle in experimental models, from non-invasive methodologies to haemodynamic evaluation and ex vivo set-ups.

Targeting myocardial remodelling to develop novel therapies for heart failure: a position paper from the Working Group on Myocardial Function of the European Society of Cardiology

The failing heart is characterized by complex tissue remodelling involving increased cardiomyocyte death, and impairment of sarcomere function, metabolic activity, endothelial and vascular function, together with increased inflammation and interstitial fibrosis. For years, therapeutic approaches for heart failure (HF) relied on vasodilators and diuretics which relieve cardiac workload and HF symptoms. The introduction in the clinic of drugs interfering with beta-adrenergic and angiotensin signalling have ameliorated survival by interfering with the intimate mechanism of cardiac compensation. Current therapy, though, still has a limited capacity to restore muscle function fully, and the development of novel therapeutic targets is still an important medical need. Recent progress in understanding the molecular basis of myocardial dysfunction in HF is paving the way for development of new treatments capable of restoring muscle function and targeting specific pathological subsets of LV dysfunction. These include potentiating cardiomyocyte contractility, increasing cardiomyocyte survival and adaptive hypertrophy, increasing oxygen and nutrition supply by sustaining vessel formation, and reducing ventricular stiffness by favourable extracellular matrix remodelling. Here, we consider drugs such as omecamtiv mecarbil, nitroxyl donors, cyclosporin A, SERCA2a (sarcoplasmic/endoplasmic Ca(2 +) ATPase 2a), neuregulin, and bromocriptine, all of which are currently in clinical trials as potential HF therapies, and discuss novel molecular targets with potential therapeutic impact that are in the pre-clinical phases of investigation. Finally, we consider conceptual changes in basic science approaches to improve their translation into successful clinical applications.

Homocysteine Thiolactone Induces Cardiac Dysfunction: Role of Oxidative Stress

This study investigates the cardiac functioning in male Wistar rats after treatments with methionine and homocysteine thiolactone (HcyT). The rats were distributed into 3 groups and treated for 8 weeks. Group I was the control (CO) group, given water, group II was treated with methionine, and group III with HcyT (100 mg/kg). Morphometric and functional cardiac parameters were evaluated by echocardiography. Superoxide dismutase (SOD), catalase, and glutathione S-transferase activities, chemiluminescence, thiobarbituric acid reactive substances, and immunocontent were measured in the myocardium. Hyperhomocysteinemia was observed in rats submitted to the both treatments. The results showed diastolic function was compromised in HcyT group, seen by the increase of E/A (peak velocity of early (E) and late (A) diastolic filling) ratio, decrease in deceleration time of E wave and left ventricular isovolumic relaxation time. Myocardial performance index was increased in HcyT group and was found associated with increased SOD immunocontent. HcyT group demonstrated an increase in SOD, catalase, and glutatione S-transferase activity, and chemiluminescence and thiobarbituric acid reactive substances. Overall, these results indicated that HcyT induces a cardiac dysfunction and could be associated with oxidative stress increase in the myocardium.

Granulocyte Colony-stimulating Factor Reduces Mortality by Suppressing Ventricular Arrhythmias in Acute Phase of Myocardial Infarction in Rats

Our aim was to evaluate the effects of granulocyte colony-stimulating factor (G-CSF) on early cardiac arrhythmias after myocardial infarction (MI) and the impact on survival. Male Wistar rats received repeated doses of 50 mu g/kg G-CSF (MI-GCSF group) or vehicle (MI group) at 7, 3, and 1 days before surgery. MI was induced by permanent occlusion of left corollary artery. The electrocardiogram was obtained before occlusion and then for 30 minutes after surgery. Events and duration of ventricular arrhythmias were analyzed. The levels of connexin43 (Cx43) were measured by Western blot immediately before MI production. Survival was significantly increased in MI-GCSF pretreated group (74% versus 52.0% MI. P < 0.05). G-CSF pretreatment also significantly reduced the ventricular premature beats when compared with the untreated-MI group (201 +/- 47 versus 679 +/- 117, P < 0.05). The number and the duration of ventricular tachycardia were smaller in the MI-G-CSF group, as well as the number of ventricular fibrillation episodes (10% versus 69% in NIL P < 0.05). Cx43 levels were significantly increased by G-CSF treatment (1.27 +/- 0.13 versus 0.86 +/- 0.11; P < 0.05). The MI size 24 hours after occlusion was reduced by G-CSF pretreatment (36 +/- 3% versus 44 +/- 2% of left ventricle in MI group; P < 0.05). The increase of Cx43 expression in the heart may explain the reduced incidence in ventricular arrhythmias in the early phases after coronary artery occlusion in rats, thus increasing survival after MI.

The Antiapoptotic Effect of Granulocyte Colony-stimulating Factor Reduces Infarct Size and Prevents Heart Failure Development in Rats

Background/Aim. Granulocyte colony-stimulating factor (G-CSF) reduces myocardial injury and improves cardiac function after myocardial infarction (MI). We investigated the early alterations provided by G-CSF and the chronic repercussions in infarcted rats. Methods. Male Wistar rats (200-250g) received vehicle (MI) or G-CSF (MI-GCSF) (50 mu g/kg, sc) at 7, 3 and 1 days before MI surgery. Afterwards MI was produced and infarct size was measured 1 and 15 days after surgery. Expression of anti-and proapoptotic proteins was evaluated immediately before surgery. 24 hours after surgery, apoptotic nuclei were evaluated. Two weeks after MI, left ventricular (LV) function was evaluated, followed by in situ LV diastolic pressure-volume evaluation. Results. Infarct size was decreased by 1 day pretreatment before occlusion (36 +/- 2.8 vs. 44 +/- 2.1% in MI; P<0.05) and remained reduced at 15 days after infarction (28 +/- 2.2 vs. 36 +/- 1.4% in MI; P<0.05). G-CSF pretreatment increased Bcl-2 and Bcl-xL protein expression, but did not alter Bax in LV. Apoptotic nuclei were reduced by treatment (Sham: 0.46 +/- 0.42, MI: 15.5 +/- 2.43, MI-GCSF: 5.34 +/- 3.34%; P<0.05). Fifteen days after MI, cardiac function remained preserved in G-CSF pretreated rats. The LV dilation was reduced in MI-G-CSF group as compared to MI rats, being closely associated with infarct size. Conclusion. The early beneficial effects of G-CSF were essentials to preserve cardiac function at a chronic stage of myocardial infarction. Copyright (C) 2011 S. Karger AG, Basel

Renal ischemia in rats: Mitochondria function and laser autofluorescence

Ischemia-reperfusion injury is the major cause of organ dysfunction or even nonfunction following transplantation. It can attenuate the long-term survival of transplanted organs. To evaluate the severity of renal ischemia injury determined by histology, we applied laser(442 nm and 532 nm) induced fluorescence (LIF), mitochondria respiration, and membrane swelling to evaluate 28 Wistar rats that underwent left kidney warm ischemia for 20, 40, 60, or 80 minutes. LIF performed before ischemia (control) was repeated at 20, 40, 60, and 80 minutes thereafter. We harvested left kidney tissue samples immediately after LIF determination for histology and mitochondrial analyses: state 3 and 4 respiration, respiration control rate (RCR), and membrane swelling. The association of optic spectroscopy with histological damage showed: LIF, 442 nm (r(2) = 0.39, P < .001) and 532 nm, (r(2) = 0.18, P = .003); reflecting laser/fluorescence-induced, 442 nm (r(2) = 0.20, P = .002) and 532 nm (r(2) = 0.004, P = .67). The associations between mitochondria function and tissue damage were: state 3 respiration (r(2) = 0.43, P = .0004), state 4 respiration (r(2) = 0.03, P = 0.38), RCR (r(2) = 0.28, P = .007), and membrane swelling (r(2) = 0.02, P = .43). The intensity of fluorescence emitted by tissue excited by laser, especially at a wave length of 442 nm, was determined in real time. Mitochondrial state 3 respiration and respiratory control ratio also exhibited good correlations with the grade of ischemic tissue damage.

The kidney in different stages of the cardiovascular continuum

Patients with chronic kidney disease are at higher risk of developing cardiovascular disease. The complex, interaction between the kidney and the cardiovascular system is incompletely understood, particularly at the early stages of the cardiovascular continuum. The overall aim of this thesis was to clarify novel aspects of the interplay between the kidney and the cardiovascular system at different stages of the cardiovascular continuum; from risk factors such as insulin resistance, inflammation and oxidative stress, via sub-clinical cardiovascular damage such as endothelial dysfunction and left ventricular dysfunction, to overt cardiovascular death. This thesis is based on two community-based cohorts of elderly, Uppsala Longitudinal Study of Adult Men (ULSAM) and Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS). The first study, show that higher insulin sensitivity, measured with euglycemic-hyperinsulinemic clamp technique was associated to improve estimated glomerular filtration rate (eGFR) in participants with normal fasting plasma glucose, normal glucose tolerance and normal eGFR. In longitudinal analyses, higher insulin sensitivity at baseline was associated with lower risk of impaired renal function during follow-up. In the second study, eGFR was inversely associated with different inflammatory markers (C-reactive protein, interleukin-6, serum amyloid A) and positively associated with a marker of oxidative stress (urinary F2-isoprostanes). In line with this, the urinary albumin/creatinine ratio was positively associated with these inflammatory markers, and negatively associated with oxidative stress. In study three, higher eGFR was associated with better endothelial function as assessed by the invasive forearm model. Further, in study four, higher eGFR was significantly associated with higher left ventricular systolic function (ejection fraction). The 5th study of the thesis shows that higher urinary albumin excretion rate (UAER) and lower eGFR was independently associated with an increased risk for cardiovascular mortality. Analyses of global model fit, discrimination, calibration, and reclassification suggest that UAER and eGFR add relevant prognostic information beyond established cardiovascular risk factors in participants without prevalent cardiovascular disease. Conclusion: this thesis show that the interaction between the kidney and the cardiovascular system plays an important role in the development of cardiovascular disease and that this interplay begins at an early asymptomatic stage of the disease process.

Analysis of cardioprotective effects using purified Saliva miltiorrhiza extract on isolated rat hearts

The purpose of the current study is to evaluate the cardioprotective effects of purified Salvia miltiorrhiza extract (PSME) on myocardial ischemia/reperfusion injury in isolated rat hearts. Hearts were excised and perfused at constant flow (7 – 9 ml · min⁻¹) via the aorta. Non-recirculating perfusion with Krebs-Henseleit (KH) solution was maintained at 37°C and continuously gassed with 95% O₂ and 5% CO₂. KH solution with or without PSME (100 mg per liter solution) was used after 30-min zero-flow ischemia for the PSME and control group, respectively. Left ventricular (LV) developed pressure; its derivatives, diastolic pressure, and so on were continuously recorded via a pressure transducer attached to a polyvinylchloride balloon that was placed in the left ventricle through an incision in the left atrium. PSME treated hearts showed significant postischemic contractile function recovery (developed pressure recovered to 44.2 ± 4.9% versus 17.1 ± 5.7%, P<0.05; maximum contraction recovered to 57.2 ± 5.9% versus 15.1 ± 6.3%, P<0.001; maximum relaxation restored to 69.3 ± 7.3% versus 15.4 ± 6.3%, P<0.001 in the PSME and control group, respectively). Significant elevation in end-diastolic pressure, which indicated LV stiffening in PSME hearts might have resulted from the excess high dose of PSME used. Further study will be conducted on the potential therapeutic value with lower dose of PSME on prevention of ischemic heart disease.

Priming vs. rhyming : orthographic and phonological representations in the left and right hemispheres

The right cerebral hemisphere has long been argued to lack phonological processing capacity. Recently, however, a sex difference in the cortical representation of phonology has been proposed, suggesting discrete left hemisphere lateralization in males and more distributed, bilateral representation of function in females. To evaluate this hypothesis and shed light on sex differences in the phonological processing capabilities of the left and right hemispheres, we conducted two experiments. Experiment 1 assessed phonological activation implicitly (masked homophone priming), testing 52 (M = 25, F = 27; mean age 19.23 years, SD 1.64 years) strongly right-handed participants. Experiment 2 subsequently assessed the explicit recruitment of phonology (rhyme judgement), testing 50 (M = 25, F = 25; mean age 19.67 years, SD 2.05 years) strongly right-handed participants. In both experiments the orthographic overlap between stimulus pairs was strictly controlled using DICE [Brew, C., & McKelvie, D. (1996). Word-pair extraction for lexicography. In K. Oflazer & H. Somers (Eds.), Proceedings of the second international conference on new methods in language processing (pp. 45–55). Ankara: VCH], such that pairs shared (a) high orthographic and phonological similarity (e.g., not–KNOT); (b) high orthographic and low phonological similarity (e.g., pint–HINT); (c) low orthographic and high phonological similarity (e.g., use–EWES); or (d) low orthographic and low phonological similarity (e.g., kind–DONE). As anticipated, high orthographic similarity facilitated both left and right hemisphere performance, whereas the left hemisphere showed greater facility when phonological similarity was high. This difference in hemispheric processing of phonological representations was especially pronounced in males, whereas female performance was far less sensitive to visual field of presentation across both implicit and explicit phonological tasks. As such, the findings offer behavioural evidence indicating that though both hemispheres are capable of orthographic analysis, phonological processing is discretely lateralised to the left hemisphere in males, but available in both the left and right hemisphere in females.

Benchmarking ventricular arrhythmias in the mouse—revisiting the ‘Lambeth Conventions’ 20 years on

The isolated Langendorff-mode perfused heart has become a valuable experimental model, used extensively to examine cardiac function, pathophysiology and pharmacology. For the clinical cardiologist an ECG is often a simple practicality, however in experimental circumstances, particularly with ex vivo murine hearts it is not always possible to obtain an ECG due to experimental recording constraints. However, the mechanical record of ventricular contractile function can be highly informative in relation to electrical state. It is difficult though to achieve consistency in these evaluations of arrhythmia as a validated common reference framework is lacking. In 1988, a group of investigators developed the ‘Lambeth Conventions’—a standardised reference for the definition and classification of arrhythmias in animal experimental models of ischaemia, infarction and reperfusion in vivo. Now, two decades later it is timely to revisit the Lambeth Conventions, and to update the guidelines in the context of the marked increase in murine heart study in experimental cardiac pathophysiology. Here we describe an adjunct to the Lambeth Conventions for the reporting of ventricular arrhythmias post-ischaemia in ex vivo mouse hearts when ECG recordings are not employed. Of seven discrete and identifiable patterns of mechanical dysrhythmia observed in reperfusion, five could be classified using conventional ECG terminology: ventricular premature beat, bigeminy, trigeminy, ventricular tachycardia and ventricular fibrillation. Two additional rhythm variations detected from the pressure record are described (potentiated contraction and alternans).

Isoflavones from red clover improve systemic arterial compliance but not plasma lipids in menopausal women

The possibility that the heightened cardiovascular risk associated with the menopause can be reduced by increasing dietary isoflavone intake was tested in 17 women by measuring arterial compliance, an index of the elasticity of large arteries such as the thoracic aorta. Compliance diminishes with age and menopause. An initial 3- to 4-week run-in period and a 5-week placebo period were followed by two 5-week periods of active treatment with 40 mg and then 80 mg isoflavones derived from red clover containing genistein, daidzein, biochanin, and formononetin in 14 and 13 women, respectively, with 3 others serving as placebo controls throughout. Arterial compliance, measured by ultrasound as a pressure (carotid artery) and volume (outflow into aorta) relationship, was determined after each period; plasma lipids were measured twice during each period. Urinary output of isoflavones was also determined. Arterial compliance rose by 23% relative to that during the placebo period with the 80-mg isoflavone dose and slightly less with the 40-mg dose (mean6SEM: placebo, 19.761.5; 40 mg, 23.760.7; 80 mg, 24.46 1.4). In the three women receiving continuous placebo, compliance was 16 6 2.2, similar to that during the run-in period for the remaining subjects (17 6 2.1). ANOVA showed a significant (P 5 , 0.001) difference between treatments; by Bonferroni multiple comparisons and by paired t test, differences were significant between placebo and 40- and 80-mg isoflavone doses (by paired t test: P50.039 for placebo vs. 40 mg; P 5 0.018 for placebo vs. 80 mg). Plasma lipids were not significantly affected. An important cardiovascular risk factor, arterial compliance, which diminishes with menopause, was significantly improved with red clover isoflavones. As diminished compliance leads to systolic hypertension and may increase left ventricular work, the findings indicate a potential new therapeutic approach for improved cardiovascular function after menopause.

Constitutionalism and beyond the dispute between the left and right

From the constitutional point of view, all ideology in a pluralistic society structures have their own status and function. The rise of China needs a healthy, diverse and balanced thinking the situation. We need a capacity of macro-narrative and a framework to develop a macro perspective, the various ideologies put this macro, the constitutional system integration. This article is about ideology than an example, the analysis and comparison of three models. The first mode is now at in the formation and development process, and our political system to adapt to the "balanced" mode. The second model is adopted, representing the "left" "right" interest groups to reach beyond the ruling party turns around, balance of interests purpose. The third is in the process of policy formulation and selection of multi-party consultation and inclusive pattern of results of various think tanks.

Altered cardiac autonomic nervous function in depression

Background:
Depression is an independent risk factor for coronary artery disease. Autonomic instability may play a mediating or moderating role in this relationship; however this is not well understood. The objective of this study was to explore cardiac autonomic function and cardiac arrhythmia in depression, the correlation between depression severity and Heart Rate Variability (HRV) related indices, and the prevalence of arrhythmia.

Methods:
Individuals (n = 53) with major depression as assessed by the Diagnostic and Statistical Manual of Mental Disorders, who had a Hamilton Rating Scale for Depression (HAMD) score ≥20 and a Zung Self-Rating Depression Scale score > 53 were compared to 53 healthy individuals, matched for age and gender. Multichannel Electrocardiograph ECG-92C data were collected over 24 hours. Long-term changes in HRV were used to assess the following vagally mediated changes in autonomic tone, expressed as time domain indices: Standard deviation of the NN intervals (SDNN), standard deviation of 5 min averaged NN intervals (SDANN), Root Mean Square of the Successive Differences (RMSSD) and percentage of NN intervals > 50 ms different from preceding interval (pNN50). Pearson’s correlations were conducted to explore the strength of the association between depression severity (using the SDS and HRV related indices, specifically SDNN and low frequency domain / high frequency domain (LF/HF)).

Results:
The values of SDNN, SDANN, RMSSD, PNN50 and HF were lower in the depression group compared to the control group (P<.05). The mean value of the LF in the depression group was higher than the in control group (P<.05). Furthermore the ratio of LF/HF was higher among the depression group than the control group (P<.05). A linear relationship was shown to exist between the severity of the depression and HRV indices. In the depression group, the prevalence of arrhythmia was significantly higher than in the control group (P<.05), particularly supraventricular arrhythmias.

Conclusions:
Our findings suggest that depression is accompanied by dysfunction of the cardiac autonomic nervous system, and further, that depression severity is linked to severity of this dysfunction. Individuals with depression appear to be susceptible to premature atrial and/or ventricular disease.

Cardiac adaptation to endurance exercise in rats

Endurance exercise is widely assumed to improve cardiac function in humans. This project has determined cardiac function following endurance exercise for 6 (n = 30) or 12 (n = 25) weeks in male Wistar rats (8 weeks old). The exercise protocol was 30 min/day at 0.8 km/h for 5 days/week with an endurance test on the 6th day by running at 1.2 km/h until exhaustion. Exercise endurance increased by 318% after 6 weeks and 609% after 12 weeks. Heart weight/kg body weight increased by 10.2% after 6 weeks and 24.1% after 12 weeks. Echocardiography after 12 weeks showed increases in left ventricular internal diameter in diastole (6.39 ± 0.32 to 7.90 ± 0.17 mm), systolic volume (49 ± 7 to 83 ± 11 μl) and cardiac output (75 ± 3 to 107 ± 8 ml/min) but not left wall thickness in diastole (1.74 ± 0.07 to 1.80 ± 0.06 mm). Isolated Langendorff hearts from trained rats displayed decreased left ventricular myocardial stiffness (22 ± 1.1 to 19.1 ± 0.3) and reduced purine efflux during pacing-induced workload increases. 31P-NMR spectroscopy in isolated hearts from trained rats showed decreased PCr and PCr/ATP ratios with increased creatine, AMP and ADP concentrations. Thus, this endurance exercise protocol resulted in physiological hypertrophy while maintaining or improving cardiac function.

Function and structure of the mirror neuron system in autism

 Utilizing MRI, this thesis identified wide-spread brain abnormalities in autism. White matter deficits were more pronounced in the left hemisphere, attributable to atypical myelination. Regarding the mirror neuron system, functional anomalies were situated in the right, dorsal, premotor cortex which further demonstrated reduced functional connectivity with the inferior parietal lobule.