Colonisation success of introduced oysters is driven by wave-related exposure

The Pacific oyster, Magallana gigas, is an extremely successful invader with established populations in marine and estuarine habitats almost all over the world. Ecological implications of the introduction of this species to indigenous communities are well documented. However, the processes by which this species successfully establishes in a recipient community is still insufficiently understood. The early detection of the oyster at the island of Helgoland (North Sea) provided the ideal opportunity to investigate whether physical mechanisms, such as wave-exposure, influence their successful colonisation. We hypothesized that oyster colonisation benefits from wave-protected conditions. For this purpose, we evaluated colonisation success of M. gigas among wave-protected sites and wave-exposed sites along the island's pier system. The densities of M. gigas were significantly higher at wave-protected sites than at wave-exposed sites, and the frequency distributions of oyster lengths indicated better growth and higher survival rates in the harbours. This higher colonisation success at wave-protected sites may be explained by the relative retention time of water masses in the harbours, probably resulting in both reduced larval drift and lower energy demands for secretion formation (i.e. firmer binding to the substrate). The fact that the density of M. gigas can vary greatly on small spatial scales depending on exposure corroborates a multiple exposure sampling approach to monitor oyster populations in order to avoid potential overestimations of population sizes in given areas.

Circulating microRNA-132 levels improve risk prediction for heart failure hospitalization in patients with chronic heart failure

AIMS

Non-coding microRNAs (miRNAs) are critically involved in cardiovascular pathophysiology. Since they are measurable in most body fluids, they have been proposed as circulating biomarkers. We examined the prognostic value of a specific candidate miRNA in a large cohort of patients with chronic heart failure (HF) enrolled in a multicentre clinical trial.

METHODS AND RESULTS

Plasma levels of miR-132 were measured using miRNA-specific PCR-based technologies at randomization in 953 patients with chronic, symptomatic HF from the GISSI-Heart Failure trial. The association with fatal (all-cause and cardiovascular death) and non-fatal events (time to first admission to hospital for cardiovascular reasons or worsening of HF) and the incremental risk prediction were estimated in adjusted models. Higher circulating miR-132 levels were independently associated with younger age, better renal filtration, ischaemic aetiology of HF, more severe HF symptoms, higher diastolic blood pressure, higher cholesterol, and male sex. After extensive adjustment for demographic, clinical, and echocardiographic risk factors and baseline NT-proBNP concentrations, miR-132 remained associated only with HF hospitalizations (hazard ratio 0.79, 95% confidence interval 0.66-0.95, P = 0.01) and improved its risk prediction with the continuous net reclassification index (cNRI 0.205, P = 0.001).

CONCLUSION

In well characterized patients with chronic HF, circulating miR-132 levels rise with the severity of HF. Lower circulating miR-132 levels improved risk prediction for HF readmission beyond traditional risk factors, but not for mortality. MiR-132 may be helpful to intensify strategies aimed at reducing re-hospitalization, which has a substantial health and economic burden in HF.

Non-coding RNAs in Development and Disease: Background, Mechanisms, and Therapeutic Approaches

Advances in RNA-sequencing techniques have led to the discovery of thousands of non-coding transcripts with unknown function. There are several types of non-coding linear RNAs such as microRNAs (miRNA) and long non-coding RNAs (lncRNA), as well as circular RNAs (circRNA) consisting of a closed continuous loop. This review guides the reader through important aspects of non-coding RNA biology. This includes their biogenesis, mode of actions, physiological function, as well as their role in the disease context (such as in cancer or the cardiovascular system). We specifically focus on non-coding RNAs as potential therapeutic targets and diagnostic biomarkers.

Mitochondrial long noncoding RNAs as blood based biomarkers for cardiac remodeling in patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a hereditary heart disease with a high risk for sudden cardiac death in young people. As a subtype, hypertrophic obstructive cardiomyopathy (HOCM) additionally has a left ventricular outflow gradient, showing stronger symptoms and requires a different treatment compared with hypertrophic nonobstructive cardiomyopathy (HNCM). In this study our aim was to investigate the regulation of mitochondrial and cardiac remodeling associated long noncoding RNAs (lncRNAs) in blood of patients affected with HOCM and HNCM. We included 28 HNCM, 57 HOCM, and 26 control inviduals. Already known mitochondrial and cardiac remodeling associated lncRNAs uc004cos.4, uc004coz.1, uc004cov.4, uc011mfi.2, uc022bqw.1, uc022bqs.1, and uc022bqu.1 were amplified in serum of these patients and correlated with clinical parameters. Long noncoding RNAs uc004cov.4 and uc022bqu.1 were significantly increased in patients with HOCM but not in patients with HNCM. With the use of receiver operator characteristic (ROC) curve analysis, lncRNAs uc004cov.4 and uc022bqu.1 were able to identify HOCM patients. In our study we evidenced that the specific mitochondrial long noncoding RNAs uc004cov.4 and uc022bqu.1 were upregulated in patients with HOCM and they were also able to identify HOCM and could be developed as useful clinical biomarkers in the future.

Vascular importance of the miR-212/132 cluster

RATIONALE

Many processes in endothelial cells including angiogenic responses are regulated by microRNAs. However, there is limited information available about their complex cross-talk in regulating certain endothelial functions.

AIM

The objective of this study is to identify endothelial functions of the pro-hypertrophic miR-212/132 cluster and its cross-talk with other microRNAs during development and disease.

METHODS AND RESULTS

We here show that anti-angiogenic stimulation by transforming growth factor-beta activates the microRNA-212/132 cluster by derepression of their transcriptional co-activator cAMP response element-binding protein (CREB)-binding protein (CBP) which is a novel target of a previously identified pro-angiogenic miRNA miR-30a-3p in endothelial cells. Surprisingly, despite having the same seed-sequence, miR-212 and miR-132 exerted differential effects on endothelial transcriptome regulation and cellular functions with stronger endothelial inhibitory effects caused by miR-212. These differences could be attributed to additional auxiliary binding of miR-212 to its targets. In vivo, deletion of the miR-212/132 cluster increased endothelial vasodilatory function, improved angiogenic responses during postnatal development and in adult mice.

CONCLUSION

Our results identify (i) a novel miRNA-cross-talk involving miR-30a-3p and miR-212, which led to suppression of important endothelial genes such as GAB1 and SIRT1 finally culminating in impaired endothelial function; and (ii) microRNAs may have different biological roles despite having the same seed sequence.

Angiotensinergic versus nonangiotensinergic hemodynamic effects of converting enzyme inhibition in patients with chronic heart failure. Assessment by acute renin and converting enzyme inhibition

BACKGROUND

The contribution of nonangiotensinergic effects of converting enzyme inhibitors to their hemodynamic effects in patients with chronic heart failure is not clear. A comparison of the effects of renin and converting enzyme inhibition should help to clarify this issue.

METHODS AND RESULTS

Thirty-six patients with chronic heart failure (New York Heart Association class II or III) were randomly assigned to receive double-blind either intravenous placebo, the renin inhibitor remikiren, or the converting enzyme inhibitor enalaprilat followed by coinfusion of a second placebo infusion, the addition of remikiren to enalaprilat, or the addition of enalaprilat to remikiren, respectively. Systemic hemodynamics (Swan-Ganz and radial artery catheters) were measured before (rest and submaximal recumbent bicycle ergometry), during (rest), and at the end (rest and exercise) of each 45-minute single- or combination-infusion period. Placebo did not change hemodynamics or renin activity. Effective inhibition of the renin-angiotensin system by remikiren and enalaprilat was indicated by increases of plasma immunoreactive renin together with rapid and complete inhibition of renin activity after remikiren and an increase after enalaprilat (all P < or = .05). Remikiren and enalaprilat rapidly and to a similar extent reduced resting blood pressure through a reduction of systemic vascular resistance, and these changes were significantly correlated to baseline plasma renin activity. Both compounds also decreased pulmonary artery, pulmonary capillary wedge, and right atrial pressures to a similar extent (P < .05). During exercise, pulmonary capillary wedge and right atrial pressures were equally reduced and stroke volume index was increased with remikiren and enalaprilat (P < .05) for both). The combination of converting enzyme with renin inhibition or vice versa did not cause additional hemodynamic changes.

CONCLUSIONS

Specific renin inhibition in patients with chronic heart failure produces short-term hemodynamic effects that are almost indistinguishable from those of converting enzyme inhibition. This finding and the lack of additional effects of converting enzyme inhibition added to renin inhibition suggest that nonangiotensinergic effects of converting enzyme inhibitors do not play a significant role in their short-term hemodynamic effects in patients with chronic heart failure.

[Electrophysiologic effects of diprafenone in supraventricular and ventricular tachycardia]

The electrophysiologic effects of diprafenone were evaluated in 31 patients (9 X AV nodal reentrant tachycardia, 9 X Wolff-Parkinson-White syndrome, 4 X paroxysmal atrial fibrillation, 10 X recurrent ventricular tachycardia). Electrophysiologic studies were performed before and after intravenous infusion of 1.5 mg/kg body weight diprafenone in a period of 10 minutes. Diprafenone prolonged the mean RR interval during sinus rhythm from 690 +/- 109 ms to 789 +/- 93 ms and the maximal sinus node recovery time from 1081 +/- 216 ms to 1300 +/- 398 ms (p less than 0.001). The effective refractory period of the right atrium increased from 195 +/- 22 ms to 210 +/- 28 ms (p less than 0.01) and of the right ventricle from 220 +/- 20 ms to 235 +/- 20 ms (p less than 0.001). Diprafenone produced a prolongation of the antegrade effective refractory period of the AV node from 260 +/- 35 ms to 294 +/- 39 ms (p less than 0.01) and of the retrograde effective refractory period from 265 +/- 76 ms to 400 +/- 130 ms (p less than 0.001). The effective refractory periods of the Kent bundle increased: antegrade from 299 +/- 45 ms to 413 +/- 133 ms, retrograde from 252 +/- 33 ms to 286 +/- 169 ms (p less than 0.05). Suppression of inducibility was observed in 12 of 17 patients with supraventricular reentrant tachycardia, in 5 of 8 patients with atrial fibrillation and in 7 of 10 patients with recurrent ventricular tachycardia. The rate of supraventricular tachycardias decreased under the influence of the substance.(ABSTRACT TRUNCATED AT 250 WORDS)