Upregulation of NOR-1 in calcified human vascular tissues: impact on osteogenic differentiation and calcification.

Cardiovascular calcification is a significant public health issue whose pathophysiology is not fully understood. NOR-1 regulates critical processes in cardiovascular remodeling, but its contribution to ectopic calcification is unknown. NOR-1 was overexpressed in human calcific aortic valves and calcified atherosclerotic lesions colocalizing with RUNX2, a factor essential for osteochondrogenic differentiation and calcification. NOR-1 and osteogenic markers were upregulated in calcifying human valvular interstitial cells (VICs) and human vascular smooth muscle cells (VSMCs). Gain- and loss-of-function approaches demonstrated that NOR-1 negatively modulates the expression of osteogenic genes relevant for the osteogenic transdifferentiation (RUNX2, IL-6, BMP2, and ALPL) and calcification of VICs. VSMCs from transgenic mice overexpressing NOR-1 in these cells (TgNOR-1VSMC) expressed lower basal levels of osteogenic genes (IL-6, BMP2, ALPL, OPN) than cells from WT littermates, and their upregulation by a high-phosphate osteogenic medium (OM) was completely prevented by NOR-1 transgenesis. Consistently, this was associated with a dramatic reduction in the calcification of both transgenic VSMCs and aortic rings from TgNOR-1VSMC mice exposed to OM. Atherosclerosis and calcification were induce in mice by the administration of AAV-PCSK9D374Y and a high-fat/high-cholesterol diet. Challenged-TgNOR-1VSMC mice exhibited decreased vascular expression of osteogenic markers, and both less atherosclerotic burden (assessed in whole aorta and lesion size in aortic arch and brachiocephalic artery) and less vascular calcification (assessed either by near-infrared fluorescence imaging or histological analysis) than WT mice. Our data indicate that NOR-1 negatively modulates the expression of genes critically involved in the osteogenic differentiation of VICs and VSMCs, thereby restraining ectopic cardiovascular calcification.

Rolipram impacts on redox homeostasis and cellular signaling in an experimental model of abdominal aortic aneurysm. / Impacto del tratamiento con rolipram sobre la homeostasis rédox y la señalización celular en un modelo experimental de aneurisma de aorta abdominal.

INTRODUCTION: Cyclic nucleotide phosphodiesterases (PDEs) of the PDE4 subfamily are responsible for the hydrolysis and subcellular compartmentalization of cAMP, a second messenger that modulates vascular functionality. We had shown that PDE4B is induced in abdominal aortic aneurysms (AAA) and that PDE4 inhibition by rolipram limits experimental aneurysms. In this study we have delved into the mechanisms underlying the beneficial effect of rolipram on AAA. METHODS: AAA were induced in ApoE-/- mice by angiotensin II (Ang II) infusion. Aneurysm formation was evaluated by ultrasonography. The expression of enzymes involved in rédox homeostasis was analyzed by real-time RT-PCR and the activation of signaling pathways by Western blot. RESULTS: Induction of PDE4B in human AAA has been confirmed in a second cohort of patients. In Ang II-infused ApoE-/- mice, rolipram increased the percentage of animals free of aneurysms without affecting the percentage of aortic ruptures. Quantitative analyses determined that this drug significantly attenuated aortic collagen deposition. Additionally, rolipram reduced the increased Nox2 expression triggered by Ang II, exacerbated Sod1 induction, and normalized Sod3 expression. Likewise, PDE4 inhibition decreased the activation of both ERK1/2 and the canonical Wnt pathway, while AKT activity was not altered. CONCLUSIONS: The inhibition of PDE4 activity modulates the expression of enzymes involved in rédox homeostasis and affects cell signaling pathways involved in the development of AAA.

Influence of sex on intracellular calcium homoeostasis in patients with atrial fibrillation.

AIMS: Atrial fibrillation (AF) has been associated with intracellular calcium disturbances in human atrial myocytes, but little is known about the potential influence of sex and we here aimed to address this issue. METHODS AND RESULTS: Alterations in calcium regulatory mechanisms were assessed in human atrial myocytes from patients without AF or with long-standing persistent or permanent AF. Patch-clamp measurements revealed that L-type calcium current (ICa) density was significantly smaller in males with than without AF (-1.15 ± 0.37 vs. -2.06 ± 0.29 pA/pF) but not in females with AF (-1.88 ± 0.40 vs. -2.21 ± 0.0.30 pA/pF). In contrast, transient inward currents (ITi) were more frequent in females with than without AF (1.92 ± 0.36 vs. 1.10 ± 0.19 events/min) but not in males with AF. Moreover, confocal calcium imaging showed that females with AF had more calcium spark sites than those without AF (9.8 ± 1.8 vs. 2.2 ± 1.9 sites/µm2) and sparks were wider (3.0 ± 0.3 vs. 2.2 ± 0.3 µm) and lasted longer (79 ± 6 vs. 55 ± 8 ms), favouring their fusion into calcium waves that triggers ITIs and afterdepolarizations. This was linked to higher ryanodine receptor phosphorylation at s2808 in women with AF, and inhibition of adenosine A2A or beta-adrenergic receptors that modulate s2808 phosphorylation was able to reduce the higher incidence of ITI in women with AF. CONCLUSION: Perturbations of the calcium homoeostasis in AF is sex-dependent, concurring with increased spontaneous SR calcium release-induced electrical activity in women but not in men, and with diminished ICa density in men only.

Mitochondrial genetic effect on atrial fibrillation: A case-control study.

Atrial fibrillation (AF) is a common arrhythmia in the general population and following cardiac surgery. The influence of mitochondrial genomics on AF pathogenesis is not fully understood. We analyzed mitochondrial variables from 78 human atrial samples collected from cardiac surgeries in the following groups: 1) permanent preoperative AF; 2) preoperative sinus rhythm (SR) with postoperative AF; and 3) pre-/postoperative SR. Haplogroup H appeared offer protection against, and haplogroup U predispose to permanent AF. mtDNA content was higher in group 2 than in 3. These findings contribute to a better understanding of the influence of mitochondria on AF pathogenesis.

Changes in Local Atrial Electrograms and Surface ECG Induced by Acute Atrial Myocardial Infarction.

BACKGROUND: Atrial coronary branch occlusion is a hardly recognizable clinical entity that can promote atrial fibrillation. The low diagnostic accuracy of the ECG could deal with the characteristics of the ischemia-induced changes in local atrial electrograms, but these have not been described. OBJECTIVES: We analyzed the effects of selective acute atrial branch occlusion on local myocardial structure, atrial electrograms, and surface ECG in an experimental model close to human cardiac anatomy and electrophysiology. METHODS: Six anesthetized open-chest anesthetized pigs underwent surgical occlusion of an atrial coronary branch arising from the right coronary artery during 4 h. Atrial electrograms and ECG were simultaneously recorded. One additional pig acted as sham control. In all cases, the hearts were processed for anatomopathological analysis. RESULTS: Atrial branch occlusion induced patchy atrial necrosis with sharp border zone. During the first 30 min of occlusion, atrial electrograms showed progressive R wave enlargement (1.8 ± 0.6 mV vs. 2.5 ± 1.1 mV, p < 0.01), delayed local activation times (28.5 ± 8.9 ms vs. 36.1 ± 16.4 ms, p < 0.01), ST segment elevation (-0.3 ± 0.3 mV vs. 1.0 ± 1.0 mV, p < 0.01), and presence of monophasic potentials. Atrial ST segment elevation decreased after 2 h of occlusion. The electrical border zone was ∼1 mm and expanded over time. After 2 h of occlusion, the ECG showed a decrease in P wave amplitude (from 0.09 ± 0.04 mV to 0.05 ± 0.04 mV after 165 min occlusion, p < 0.05) and duration (64.4 ± 8.0 ms vs. 80.9 ± 12.6 ms, p < 0.01). CONCLUSION: Selective atrial branch occlusion induces patchy atrial infarction and characteristic changes in atrial activation, R/S wave, and ST segment that are not discernible at the ECG. Only indirect changes in P wave amplitude and duration were appreciated in advanced stages of acute coronary occlusion.

Profibrotic, Electrical, and Calcium-Handling Remodeling of the Atria in Heart Failure Patients With and Without Atrial Fibrillation.

Atrial fibrillation (AF) and heart failure (HF) are common cardiovascular diseases that often co-exist. Animal models have suggested complex AF-promoting atrial structural, electrical, and Ca2+-handling remodeling in the setting of HF, but data in human samples are scarce, particularly regarding Ca2+-handling remodeling. Here, we evaluated atrial remodeling in patients with severe left ventricular (LV) dysfunction (HFrEF), long-standing persistent ('chronic') AF (cAF) or both (HFrEF-cAF), and sinus rhythm controls with normal LV function (Ctl) using western blot in right-atrial tissue, sharp-electrode action potential (AP) measurements in atrial trabeculae and voltage-clamp experiments in isolated right-atrial cardiomyocytes. Compared to Ctl, expression of profibrotic markers (collagen-1a, fibronectin, periostin) was higher in HFrEF and HFrEF-cAF patients, indicative of structural remodeling. Connexin-43 expression was reduced in HFrEF patients, but not HFrEF-cAF patients. AP characteristics were unchanged in HFrEF, but showed classical indices of electrical remodeling in cAF and HFrEF-cAF (prolonged AP duration at 20% and shorter AP duration at 50% and 90% repolarization). L-type Ca2+ current (ICa,L) was significantly reduced in HFrEF, cAF and HFrEF-cAF, without changes in voltage-dependence. Potentially proarrhythmic spontaneous transient-inward currents were significantly more frequent in HFrEF and HFrEF-cAF compared to Ctl, likely resulting from increased sarcoplasmic reticulum (SR) Ca2+ load (integrated caffeine-induced current) in HFrEF and increased ryanodine-receptor (RyR2) single-channel open probability in HFrEF and HFrEF-cAF. Although expression and phosphorylation of the SR Ca2+-ATPase type-2a (SERCA2a) regulator phospholamban were unchanged in HFrEF and HFrEF-cAF patients, protein levels of SERCA2a were increased in HFrEF-cAF and sarcolipin expression was decreased in both HFrEF and HFrEF-cAF, likely increasing SR Ca2+ uptake and load. RyR2 protein levels were decreased in HFrEF and HFrEF-cAF patients, but junctin levels were higher in HFrEF and relative Ser2814-RyR2 phosphorylation levels were increased in HFrEF-cAF, both potentially contributing to the greater RyR2 open probability. These novel insights into the molecular substrate for atrial arrhythmias in HF-patients position Ca2+-handling abnormalities as a likely trigger of AF in HF patients, which subsequently produces electrical remodeling that promotes the maintenance of the arrhythmia. Our new findings may have important implications for the development of novel treatment options for AF in the context of HF.

Perceval Less Invasive Aortic Replacement Register: multicentric Spanish experience with the Perceval S bioprosthesis in moderate-high-risk aortic surgery.

OBJECTIVES: The development of new percutaneous and surgical techniques has reduced the risk associated with aortic valve replacement procedures. We present the results of a Spanish register after initiating a programme for sutureless prostheses in moderate-high-risk patients. METHODS: This prospective multicentre study was carried out from November 2013 to November 2016. Data were obtained from 448 patients in whom a Perceval S prosthesis was implanted. RESULTS: The mean age was 79.24 (standard deviation [SD] 4.1) years, and 61.2% were women. The estimated EuroSCORE I log risk was 11.15% (SD 7.6), with an observed mortality of 4.4% (20 patients). Isolated aortic valve replacement was performed on 69.26% of patients, with 64% involving ministernotomy. The incidence of neurological events was 2%, with 2 permanent cerebrovascular accidents, and 41 (9.2%) patients were implanted with a permanent endocavitary pacemaker. At discharge, 12 (2.6%) patients presented minimal periprosthetic leakage, and 4 (0.89%) patients had moderate leakage. There were 3 reinterventions during follow-up (2 endocarditis and 1 dysfunction due to periprosthetic leak progression). The mean gradient at discharge, 6 months and 1 year was 12.94 (SD 5.3) mmHg, 12.19 (SD 4.7) mmHg and 11.77 (SD 4.7) mmHg, respectively; 59.4% of the patients were octogenarians, with a survival rate of 98% at both 6 months and 1 year at discharge. There was neither valve migration nor early structural degeneration. The mean follow-up was 12 ± 3 months. The 6-month and 1-year mortality was 1.4% and 2.1%, respectively. CONCLUSIONS: This is a prospective multicentric study on the largest cohort of patients with sutureless valves conducted in Spain to date. It is a reproducible procedure that has enabled surgery on patients with a moderate-high risk with low morbidity and mortality, providing good haemodynamic results.

Use of the Perceval Sutureless Valve in Active Prosthetic Aortic Valve Endocarditis.

BACKGROUND: Surgical treatment of active prosthetic aortic valve endocarditis presents a challenge for cardiac surgeons because of tissue friability and destruction caused by infection. Sutureless prostheses, such as the Perceval S (LivaNova, Saluggia, Italy), have emerged as an option among the different surgical approaches for these complicated cases. METHODS: This study presents data from 9 patients who underwent aortic valve re-replacement with the Perceval S because of active prosthetic aortic valve endocarditis between January 2014 and August 2016. Hemodynamic performance (mean transprosthetic gradient and type of aortic regurgitation) was assessed intraoperatively after weaning from cardiopulmonary bypass, at discharge, and to 6 months postoperatively. RESULTS: After weaning from cardiopulmonary bypass, cases 1 and 3 through 6 had no or trivial aortic regurgitation, cases 7 and 8 presented with trivial to mild regurgitation, case 9 showed mild intraprosthetic regurgitation, and case 2 had mild periprosthetic regurgitation. Cases 4 and 7 died of septic shock and multiorgan failure in the perioperative period. In the remaining patients, severity of aortic regurgitation maintained practically invariable at discharge compared with intraoperative results. These 7 patients did well at 6-month follow-up, with good clinical and hemodynamic performance of the Perceval S prosthesis. The median of mean transprosthetic gradient was 11 mm Hg (interquartile range: 10 to 12 mm Hg). Only patient 2 showed mild periprosthetic regurgitation; patient 9 showed mild intraprosthetic insufficiency, and the remaining patients had no or trivial regurgitation. CONCLUSIONS: The sutureless Perceval S valve is a reasonable alternative for surgical treatment of prosthetic aortic valve endocarditis.