[MITRA-FR and COAPT : Why are the results so different and what are the consequences for the daily routine?] / MITRA-FR und COAPT : Warum sind die Ergebnisse so unterschiedlich, und welche Konsequenzen ergeben sich für den Alltag?

Percutaneous mitral valve repair with the MitraClip in the COAPT study significantly reduced overall mortality and hospitalization in patients with at least moderate to severe mitral valve regurgitation, in comparison to guideline-compliant drug treatment alone. Consequently, the assumption that secondary mitral regurgitation is more a consequence than the cause of systolic heart failure needs to be revised; however, data from the simultaneously published MITRA-FR study showed no prognostic benefits for patients with advanced heart failure and severely enlarged left ventricle; therefore, MitraClip treatment should only be performed after careful patient selection and heart team decision. With respect to future patient selection further studies are needed to better define cut-offs for treatment or exclusion criteria and to identify patients who profit the most from treatment. Also, new catheter-based techniques and alternative approaches to treat functional mitral regurgitation need to be investigated.

Interventional approaches to mitral regurgitation. What's in the pipeline?

Mitral regurgitation (MR) is the most prevalent valvular heart disease in the Western world. Surgical repair is the gold standard for the treatment of degenerative MR in low-risk patients. Given the rising number of patients with functional MR and higher operative risk due to relevant comorbidities and increasing age, interventional approaches to repair or replace diseased mitral valves are on the rise. However, the complex anatomy and physiology of the mitral valve and its adjacent valve apparatus bear major challenges. To date, only the MitraClip device has been used in a large number of patients; however, several other devices and systems specifically targeted at different underlying pathologies of MR are currently under development. In addition to valve repair, the first steps toward mitral valve replacement have been taken. The present article reviews the current state of the art of interventional approaches to mitral valve disease and its future perspectives.

Mitral regurgitation in patients with heart failure. Interventional therapies.

Mitral regurgitation (MR) is a common complication in heart failure patients, severely worsening their outcome. Because of the high perioperative risk, mitral valve surgery, which is the standard therapy for MR, is often not offered to these patients. Interventional therapies for mitral valve therapy might therefore constitute a novel therapeutic option particularly in this group. This article gives an overview of the available and evolving interventional strategies for mitral valve repair with a special emphasis on heart failure patients.

Significance of myeloperoxidase plasma levels as a predictor for cardiac resynchronization therapy response.

OBJECTIVES: This study aimed to determine if changes in myeloperoxidase (MPO) levels correlate with response to cardiac resynchronization therapy (CRT) and the potential role of MPO as a predictor of response to CRT. BACKGROUND: CRT is a well-established treatment option in chronic heart failure (CHF) with 50-80% of patients benefiting. Inflammation and oxidative stress play a key role in CHF pathophysiology. Previous studies have demonstrated increased levels of MPO in CHF patients, but the correlation with CRT response remains incompletely understood. METHODS: Fifty-three patients underwent CRT implantation. During follow-up, patients were divided into two groups, responders and non-responders to CRT, based on improved physical capacity and NYHA classification. Levels of MPO and NT-pro-brain-natriuretic-peptide (NT-proBNP) were determined prior to implantation, 30 and 90 days after. Physical capacity, including a 6-min walking-test, NYHA class, and LVEF were evaluated at baseline and during follow-up. RESULTS: Thirty-four patients (64%) responded to CRT, showing improved physical capacity and LVEF. All responders revealed a significant decrease of MPO levels (503.8 ng/ml vs. 188.4 ng/ml; p < 0.001). Non-responding patients did not show any significant changes in clinical parameters or MPO levels (119.6 ng/ml vs. 134.3 ng/ml; p = 0.672) during follow-up. At baseline, physical capacity and NYHA class, as well as MPO levels differed significantly between both groups (p < 0.001). A ROC analysis identified an MPO cut-off value for response to CRT of 242 ng/ml with a sensitivity of 93.5% and specificity of 71.4%. There was a strong correlation between MPO and improvement of LVEF (Spearman's rho: - 0.453; p = 0.005) and physical capacity (Spearman's rho: - 0.335; p = 0.042). CONCLUSIONS: Response to CRT and course of MPO levels correlate significantly. MPO levels differ between responders and non-responders prior to CRT, which may indicate an additional value of MPO as a predictor for CRT response. Further randomized studies are required to confirm our data in larger patient cohorts.

Modification of a Chlamydomonas reinhardtii CRISPR/Cas9 transformation protocol for use with widely available electroporation equipment.

A recently reported protocol demonstrates efficient CRISPR/Cas9 gene editing of Chlamydomonas reinhardtii[1]. The published protocol demonstrates transformation and editing of a wall-less strain of C. reinhardtii using plasmid encoded Cas9 and sgRNA. However, the published protocol utilizes a complex electroporation waveform that cannot be generated by most electroporation systems. It is unknown whether transformation via this complex electroporation waveform is essential for high efficiency of Cas9 edits, perhaps by optimizing Cas9 or guide RNA gene expression or incorporation into the genome. We demonstrate that a simple electroporation waveform can deliver plasmid encoded CRISPR/Cas9 into and edit the genome of a wall-less strain of C. reinhardtii as efficiently as the more complex waveform. Our modified electroporation protocol makes the plasmid based CRISPR/Cas9 genome editing method accessible to a greater number of Chlamydomonas researchers.•Our protocol uses a simple electroporation waveform to replace a complex waveform used to achieve efficient CRISPR/Cas9 gene editing in a wall-less strain of Chlamydomonas reinhardtii.•We also increased concentration of plasmids to maintain high gene editing efficiency.•We minimized modifications to other steps of the original protocol.

The effect of Fe doping on adsorption of CO2/N2 within carbon nanotubes: a density functional theory study with dispersion corrections.

An ab initio density functional theory (DFT) study with correction for dispersive interactions was performed to study the adsorption of N(2) and CO(2) inside an (8, 8) single-walled carbon nanotube. We find that the approach of combining DFT and van der Waals correction is very effective for describing the long-range interaction between N(2)/CO(2) and the carbon nanotube (CNT). Surprisingly, exohedral doping of an Fe atom onto the CNT surface will only affect the adsorption energy of the quadrupolar CO(2) molecule inside the CNT (20-30%), and not that of molecular N(2). Our results suggest the feasibility of enhancement of CO(2)/N(2) separation in CNT-based membranes by using exohedral doping of metal atoms.

Acute and Long-Term Hemodynamic Effects of MitraClip Implantation on a Preexisting Secondary Right Heart Failure.

Positive results of MitraClip in terms of improvement in clinical and left ventricular parameters have been described in detail. However, long-term effects on secondary pulmonary hypertension were not investigated in a larger patient cohort to date. 70 patients with severe mitral regurgitation, additional pulmonary hypertension, and right heart failure as a result of left heart disease were treated in the heart centers Hamburg and Göttingen. Immediately after successful MitraClip implantation, a reduction of the RVOT diameter from 3.52 cm to 3.44 cm was observed reaching a statistically significant value of 3.39 cm after 12 months. In contrast, there was a significant reduction in the velocity of the tricuspid regurgitation (TR) from 4.17 m/s to 3.11 m/s, the gradient of the TR from 48.5 mmHg to 39.3 mmHg, and the systolic pulmonary artery pressure (PAPsyst) from 58.6 mmHg to 50.0 mmHg. This decline continued in the following months (Vmax TR 3.09 m/s, peak TR 38.6 mmHg, and PAPsyst 47.4 mmHg). The tricuspid annular plane systolic excursion (TAPSE) increased from 16.5 mm to 18.9 mm after 12 months. MitraClip implantation improves pulmonary artery pressure, tricuspid regurgitation, and TAPSE after 12 months. At the same time, there is a decrease in the RVOT diameter without significant changes in other right ventricular and right atrial dimensions.

Microdialysis of extracellular endogenous opioid peptides from rat brain in vivo.

The combination of microdialysis and a highly sensitive radioimmunoassay was developed in order to monitor the in vivo extracellular levels of endogenous opioid peptides from discrete regions of the rat brain. The radioimmunoassay cross-reacts 100% with peptides with alpha N-acetyl Tyr.Gly.Gly.Phe-Met or -Leu at the N terminus and thus recognizes all known endogenous opioid peptide fragments following acetylation of the sample. The assay was conducted on solid phase with antibody bound via protein A to 96-well plates and provided a limit of detection of approximately 0.2 fmol. A variety of dialysis membranes were evaluated with respect to their efficiency in recovering opioid peptides in vitro. Custom-made probes (4 mm active length) manufactured from polyacrylonitrile membranes and commercially available polycarbonate membrane probes proved most suitable with relative recoveries for [Met]- and [Leu]enkephalin in the range 6-10% at a flow rate of 2.7 microliters/min. Probes implanted in the globus pallidus/ventral pallidum of halothane/N2O anaesthetized rats recovered approximately 1.5 fmol of immunoreactive opioid material per 30-min sample in the absence of peptidase inhibitors. The majority of this immunoreactivity co-eluted with [Met]- and [Leu]enkephalin on reverse-phase high-performance liquid chromatography. A 2-min pulse of 100 mM K(+)-containing artificial cerebrospinal fluid in the perfusion medium during a 30-min sampling period increased the recovered immunoreactive material to 43.9 fmol +/- 12.4 S.E.M. A second stimulation 3 h later also resulted in elevated levels with an S2:S1 ratio of 0.64 +/- 0.03. The second stimulation was completely blocked by perfusion of a 10 mM EGTA-containing medium, basal release on average remaining unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)

Dual determination of extracellular cholecystokinin and neurotensin fragments in rat forebrain: microdialysis combined with a sequential multiple antigen radioimmunoassay.

Microdialysis was combined with a highly sensitive sequential multiple antigen radioimmunoassay to simultaneously measure extracellular cholecystokinin and neurotensin fragments from discrete regions of the rat brain in vivo. The assay was conducted in 96-well plates and provided a limit of detection for both peptides of 0.1 fmol. Dialysis membranes composed of polyacrylonitrile, Cuprophan and polycarbonate were evaluated in vitro using both radiolabelled peptides and radioimmunoassay. Polycarbonate probes were implanted in the posterior medial nucleus accumbens-septum, medial caudate nucleus or medial prefrontal cortex of halothane-N2O-anaesthetized rats. Cholecystokinin immunoreactivity levels were generally above the assay detection limits (0.1-0.7 fmol) in 30-min samples from all three regions under basal conditions. Recovered basal amounts of neurotensin immunoreactivity were detectable in the nucleus accumbens-septum in approximately 50% of experiments (0.1-0.2 fmol) but were not measured in the caudate nucleus or prefrontal cortex. In the nucleus accumbens-septum, a 10-min pulse of 200 mM K(+)-containing artificial cerebrospinal fluid in the perfusion medium during a 30-min sampling period increased the recovered cholecystokinin and neurotensin immunoreactivity to 9.7 fmol +/- 1.9 S.E.M. and 5.8 +/- 1.6 S.E.M., respectively. A second stimulation following a 2.5-h interval produced similar elevations with S2:S1 ratios of 0.62 +/- 0.07 and 0.68 +/- 0.07 for cholecystokinin and neurotensin, respectively. In a separate series of experiments the second stimulation of both peptides was prevented by perfusion of a 10 mM EGTA-containing medium. Similar results were obtained in the caudate nucleus for cholecystokinin, but K(+)-induced elevations in neurotensin immunoreactivity were much smaller (0.5 fmol) in this brain region and calcium dependency was not established. Sequential K+ stimulations at 50, 100 and 200 mM produced progressively greater increases in recovered cholecystokinin and neurotensin immunoreactivity from the nucleus accumbens-septum and of cholecystokinin immunoreactivity from the prefrontal cortex. No neurotensin immunoreactivity was detected in the prefrontal cortex following K+ stimulation. Large post mortem increases in the recovered amounts of cholecystokinin and neurotensin immunoreactivity were observed. This effect was significantly attenuated by EGTA although there was a large calcium-independent component of the cholecystokinin immunoreactivity. On reverse-phase high-performance liquid chromatography the major cholecystokinin-immunoreactive peak co-eluted with sulphated cholecystokinin octapeptide. Neurotensin-immunoreactive material co-eluted with neurotensin (1-13), neurotensin (1-12), neurotensin (1-11), neurotensin (1-10) and neurotensin (1-8). These results further demonstrate the potential of microdialysis for studying neuropeptide release and metabolism in vivo when combined with sufficiently sensitive assay procedures.

Permeation of binary gas mixtures in ultramicroporous membranes.

High-quality nanometer thick ultramicroporous membranes were prepared from silica sol-gel processes and tested for the permeation of binary gas mixtures of He, H2, CO2, and CH4 across different temperature and partial pressure regimens. Pore size distribution by molecular probing showed that the majority of pore sizes had dimensions below 2.9 A. In 50:50 binary mixtures, the fluxes of gases increased as a function of temperature, indicating an activated transport mechanism. The ultramicroporous membranes showed high selectivities at 150 degrees C for He/CO2 (30), He/CH4 (93), H2/CO2 (10), and H2/CH4 (9) with lower selectivities for CO2/CH4 (5). High activation energies (Ea) were observed for the permeance of 50:50 binary mixtures containing He and H2 of 22.1-27.5 and 17.6-23.1 kJ.mol-1, respectively. The Ea for the permeance of the total mixture approached the Ea for the permeance of the molecule with the smaller kinetic diameter (He or H2).

Predominance of left-sided fractures of the proximal femur in a geriatric population.

Two hundred consecutive admissions to a community medical center with a diagnosis of proximal femoral fracture were analyzed to determine the left:right ratio. It was found that there were 134 left-sided and 66 right-sided fractures. Although no apparent reason was noted, this appears to be a significant finding that warrants further investigation.

Cardiac remodeling following percutaneous mitral valve repair - initial results assessed by cardiovascular magnetic resonance imaging.

PURPOSE: Percutaneous mitral valve repair with the MitraClip device (Abbott Vascular, Redwood City, California, USA) is a novel therapeutic option in patients with mitral regurgitation. This study evaluated the feasibility of cardiac volume measurements by cardiovascular magnetic resonance imaging (CMR) to assess reverse myocardial remodeling in patients after MitraClip implantation. MATERIALS AND METHODS: 12 patients underwent CMR at baseline (BL) before and at 6 months follow-up (FU) after MitraClip implantation. Cine-CMR was performed in short- and long-axes for the assessment of left ventricular (LV), right ventricular (RV) and left atrial (LA) volumes. RESULTS: Assessment of endocardial contours was not compromised by the device-related artifact. No significant differences in observer variances were observed for LV, RV and LA volume measurements between BL and FU. LV end-diastolic (median 127 [IQR 96 - 150] vs. 112 [86 - 150] ml/m(2); p = 0.03) and LV end-systolic (82 [54 - 91] vs. 69 [48 - 99] ml/m(2); p = 0.03) volume indices decreased significantly from BL to FU. No significant differences were found for RV end-diastolic (94 [75 - 103] vs. 99 [77 - 123] ml/m(2); p = 0.91), RV end-systolic (48 [42 - 80] vs. 51 [40 - 81] ml/m(2); p = 0.48), and LA (87 [55 - 124] vs. 92 [48 - 137] ml/m(2); p = 0.20) volume indices between BL and FU. CONCLUSION: CMR enables the assessment of cardiac volumes in patients after MitraClip implantation. Our CMR findings indicate that percutaneous mitral valve repair results in reverse LV but not in RV or LA remodeling. KEY POINTS: • Volume measurements by cardiovascular magnetic resonance imaging are feasible following percutaneous mitral valve repair despite device-related artifacts.• A significant reduction of left ventricular volume was found in terms of beneficial, reverse left ventricular remodeling after 6-month follow-up.• No significant reduction was found in right ventricular or left atrial volumes after percutaneous mitral valve repair after 6-month follow-up.

Percutaneous interventional mitral regurgitation treatment using the Mitra-Clip system.

The interventional treatment of mitral valve regurgitation by the MitraClip procedure has grown rapidly in Germany and Europe during the past years. The MitraClip procedure has the potential to treat high-risk patients with secondary mitral valve regurgitation and poor left ventricular function. Furthermore, patients with primary mitral valve regurgitation may be treated successfully by the MitraClip procedure in case of high surgical risk or in very old patients. At the same time it has been emphasised that the MitraClip interventional treatment is still at an early stage of clinical development. The largest clinical experience with the MitraClip procedure so far is probably present in some German cardiovascular centers, which here summarise their recommendations on the current indications and procedural steps of the MitraClip treatment. These recommendations of the AGIK and ALKK may present a basis for future development.

Detection and quantification of protein adduction by electrophilic fatty acids: mitochondrial generation of fatty acid nitroalkene derivatives.

Nitroalkene fatty acid derivatives manifest a strong electrophilic nature, are clinically detectable, and induce multiple transcriptionally regulated anti-inflammatory responses. At present, the characterization and quantification of endogenous electrophilic lipids are compromised by their Michael addition with protein and small-molecule nucleophilic targets. Herein, we report a trans-nitroalkylation reaction of nitro-fatty acids with beta-mercaptoethanol (BME) and apply this reaction to the unbiased identification and quantification of reaction with nucleophilic targets. Trans-nitroalkylation yields are maximal at pH 7 to 8 and occur with physiological concentrations of target nucleophiles. This reaction is also amenable to sensitive mass spectrometry-based quantification of electrophilic fatty acid-protein adducts upon electrophoretic resolution of proteins. In-gel trans-nitroalkylation reactions also permit the identification of protein targets without the bias and lack of sensitivity of current proteomic approaches. Using this approach, it was observed that fatty acid nitroalkenes are rapidly metabolized in vivo by a nitroalkene reductase activity and mitochondrial beta-oxidation, yielding a variety of electrophilic and nonelectrophilic products that could be structurally characterized upon BME-based trans-nitroalkylation reaction. This strategy was applied to the detection and quantification of fatty acid nitration in mitochondria in response to oxidative inflammatory conditions induced by myocardial ischemia-reoxygenation.

Postmortem changes in rat brain extracellular opioid peptides revealed by microdialysis.

Microdialysis combined with a solid-phase radioimmunoassay was used to monitor changes in extracellular opioid peptide levels in the rat globus pallidus/ventral pallidum as a result of terminal brain ischemia. Ischemia was induced by anesthetic overdose or by severance of blood vessels supplying the brain. In control animals the recovered immunoreactivity increased an average of 13-fold in the 30-min sample following anesthetic overdose. Perfusion of a calcium-free, 10 mM EGTA-containing medium through the dialysis probe significantly attenuated the amplitude of this response, with the average increase being only threefold. Shorter sampling intervals (5 min) indicated that release of opioid peptide material into the extracellular environment occurs within the first 5 min of ischemia resulting from severance of the blood supply to the brain. HPLC analysis identified the majority of the postmortem-induced immunoreactive material as Met- and Leu-enkephalin.