Nanotechnology in development of next generation of stent and related medical devices: Current and future aspects.

Coronary stents have saved millions of lives in the last three decades by treating atherosclerosis especially, by preventing plaque protrusion and subsequent aneurysms. They attenuate the vascular SMC proliferation and promote reconstruction of the endothelial bed to ensure superior revascularization. With the evolution of modern stent types, nanotechnology has become an integral part of stent technology. Nanocoating and nanosurface fabrication on metallic and polymeric stents have improved their drug loading capacity as well as other mechanical, physico-chemical, and biological properties. Nanofeatures can mimic the natural nanofeatures of vascular tissue and control drug-delivery. This review will highlight the role of nanotechnology in addressing the challenges of coronary stents and the recent advancements in the field of related medical devices. Different generations of stents carrying nanoparticle-based formulations like liposomes, lipid-polymer hybrid NPs, polymeric micelles, and dendrimers are discussed highlighting their roles in local drug delivery and anti-restenotic properties. Drug nanoparticles like Paclitaxel embedded in metal stents are discussed as a feature of first-generation drug-eluting stents. Customized precision stents ensure safe delivery of nanoparticle-mediated genes or concerted transfer of gene, drug, and/or bioactive molecules like antibodies, gene mimics via nanofabricated stents. Nanotechnology can aid such therapies for drug delivery successfully due to its easy scale-up possibilities. However, limitations of this technology such as their potential cytotoxic effects associated with nanoparticle delivery that can trigger hypersensitivity reactions have also been discussed in this review. This article is categorized under: Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Surgical repair of post myocardial infarction ventricular septal defect: a retrospective analysis of a single institution experience.

INTRODUCTION: Ventricular septal defect (VSD) is a mechanical complication of acute myocardial infarction (MI) with a very high mortality, despite advances in surgical and circulatory support. The tremendous hemodynamic disturbance and the severely fragile myocardium render surgical repair a great challenge. The optimal time of surgical repair with or without circulatory support is still controversial. OBJECTIVE: The aim of this study is to review our experience with early surgical repair of post-MI VSD in a single major cardiac institution in China. METHODS: From January 2013 to October 2020, 9consecutive patients presented to our emergency department with a diagnosis of post-MI VSD. Among them, 8 were male, and the mean age was 58 ± 7years. The mean VSD size was 22.5 ± 5.7 mm. In all patients, an intra-aortic balloon pump (IABP)was inserted immediately after admission to cardiac surgery service. All patients were operated at a mean of 3.3 ± 2.9 days, and 4 within 24 h of the rupture (range 1 to 9 days post-VSD). In 5 cases, the VSD was located superiorly, and 4 cases in the posterior septum. RESULTS: The overall 30-day mortality was 11% (1/9). Coronary angiography was performed in all nine patients, four with single vessel disease had coronary stents implanted, and the other five received concomitant coronary artery bypass grafting during VSD repair surgery. There was no death in all 5 patients with anterior septal perforation. One patient with posterior septal perforation died in the operating room due to bleeding from the ventriculotomy site. Three survived patients were diagnosed with a small residual defect and mild left to right shunt post-repair. However, no further intervention was required, and patients remained asymptomatic (Killip II in 1 and III in 2). CONCLUSION: In our experience, immediate insertion of IABP and hemodynamic stabilization with early surgical intervention of VSD repair and concomitant coronary revascularization provided an 89% survival rate.

Controlled and customizable baculovirus NOS3 gene delivery using PVA-based hydrogel systems.

Nitric oxide synthase 3 (NOS3) eluting polyvinyl alcohol-based hydrogels have a large potential in medical applications and device coatings. NOS3 promotes nitric oxide and nitrate production and can effectively be delivered using insect cell viruses, termed baculoviruses. Nitric oxide is known for regulating cell proliferation, promoting blood vessel vasodilation, and inhibiting bacterial growth. The polyvinyl alcohol (PVA)-based hydrogels investigated here sustained baculovirus elution from five to 25 days, depending on the hydrogel composition. The quantity of viable baculovirus loaded significantly declined with each freeze-thaw from one to four (15.3 ± 2.9% vs. 0.9 ± 0.5%, respectively). The addition of gelatin to the hydrogels protected baculovirus viability during the freeze-thaw cycles, resulting in a loading capacity of 94.6 ± 1.2% with sustained elution over 23 days. Adding chitosan, PEG-8000, and gelatin to the hydrogels altered the properties of the hydrogel, including swelling, blood coagulation, and antimicrobial effects, beneficial for different therapeutic applications. Passive absorption of the baculovirus into PVA hydrogels exhibited the highest baculovirus loading (96.4 ± 0.6%) with elution over 25 days. The baculovirus-eluting hydrogels were hemocompatible and non-cytotoxic, with no cell proliferation or viability reduction after incubation. This PVA delivery system provides a method for high loading and sustained release of baculoviruses, sustaining nitric oxide gene delivery. This proof of concept has clinical applications as a medical device or stent coating by delivering therapeutic genes, improving blood compatibility, preventing thrombosis, and preventing infection.

Outcomes in Patients Undergoing Surgical Aortic Valve Replacement With vs Without a Preoperative Heart Team Assessment.

Background: This study sought to compare characteristics and outcomes of patients who underwent surgical aortic valve replacement (SAVR) after being referred to a heart team (HT), to those of patients referred directly for SAVR. Methods: An analysis of patients who underwent SAVR from 2015 to 2020 was conducted. Patients were categorized into 3 groups, as follows: (i) H-HT: patients referred to the HT from 2015 to 2017 (historical cohort); (ii) C-HT: patients referred to the HT from 2018 to 2020 (contemporary cohort); and (iii) No-HT: patients referred directly to cardiac surgery from 2018 to 2020. Two subanalyses were performed: H-HT vs C-HT patients, and C-HT vs No-HT patients. The primary outcome was a composite of in-hospital mortality, prolonged intubation, reoperation, sternal wound infection, and stroke. Results: This study consisted of 288 patients, distributed as follows: H-HT (n = 45); C-HT (n = 51); and No-HT (n = 192). The mean ages of H-HT, C-HT, and No-HT patients was 76.3 ± 6.9 years, 73.3 ± 7.6 years, and 69.6 ± 9.7 years, respectively (P = 0.0001). H-HT, C-HT, and No-HT patients had average Society of Thoracic Surgeons scores of 4.8 ± 2.2, 3.2 ± 1.6, and 4.2 ± 2 (P = 0.002), respectively. The composite outcome rate was more than 5 times higher among H-HT patients compared to that among the C-HT patients (20.0 vs 3.9%, P = 0.02), and was numerically higher in No-HT compared to C-HT patients (13.0 vs 3.9%, P = 0.07). Conclusions: Referral to an HT appears to be primarily driven by higher chronological age rather than overall risk profile. Patients assessed by the HT prior to undergoing SAVR have a low incidence of complications, comparable to that among patients referred directly to cardiac surgery.

Contexte: Cette étude visait à comparer les caractéristiques et le devenir de patients ayant subi une chirurgie de remplacement valvulaire aortique après avoir été orientés vers une équipe de cardiologie (EC) à ceux de patients orientés directement en chirurgie cardiaque pour une chirurgie de remplacement valvulaire aortique. Méthodologie: Une analyse portant sur les patients ayant subi une chirurgie de remplacement valvulaire aortique de 2015 à 2020 a été effectuée. Les patients ont été divisés en trois groupes, à savoir : i) CH-POEC : patients orientés vers une EC de 2015 à 2017 (cohorte historique); ii) CC-POEC : patients orientés vers une EC de 2018 à 2020 (cohorte contemporaine); iii) PODC : patients orientés directement en chirurgie cardiaque de 2018 à 2020. Deux sous-analyses ont été effectuées : CH-POEC vs CC-POEC, et CC-POEC vs PODC. Le paramètre d'évaluation principal était composite. Il comprenait la mortalité hospitalière, l'intubation prolongée, la réopération, l'infection de la plaie sternale et l'accident vasculaire cérébral. Résultats: L'étude regroupait 288 patients, répartis comme suit : CH-POEC, n = 45; CC-POEC, n = 51; PODC, n = 192. L'âge moyen dans les groupes CH-POEC, CC-POEC et PODC était respectivement de 76,3 ± 6,9 ans, 73,3 ± 7,6 ans et 69,6 ± 9,7 ans (P = 0,0001). Les groupes CH-POEC, CC-POEC et PODC présentaient des indices STS (Society of Thoracic Surgeons) moyens de 4,8 ± 2,2, 3,2 ± 1,6 et 4,2 ± 2 (P = 0,002), respectivement. Le taux composite d'événements au sein du groupe CH-POEC était plus de cinq fois supérieur à celui noté dans le groupe CC-POEC (20,0 vs 3,9 %, P = 0,02). Il était aussi plus élevé au sein du groupe PODC comparativement au groupe CC-POEC (13,0 vs 3,9 %, P = 0,07). Conclusions: Le principal motif d'orientation vers une EC semble être un âge chronologique avancé plutôt que le profil de risque global. Chez les patients qui sont évalués par une EC avant de subir une chirurgie de remplacement valvulaire aortique, l'incidence de complications est faible et comparable à celle observée chez les patients orientés directement en chirurgie cardiaque.

Interchangeability of transthoracic and transesophageal echocardiographic right heart measurements in the perioperative setting and correlation with hemodynamic parameters.

Reduction of right ventricular (RV) function after cardiac surgery has been shown to impact outcomes. Conventional indices for right ventricular dysfunction are validated using transthoracic echocardiogram (TTE) which has limited use compared to transesophageal echocardiogram (TEE) in the perioperative settings. The aim of this study was to assess the agreement of RV systolic function assessment with TEE compared to TTE and assess the association of echocardiographic parameter with hemodynamic indices of RV dysfunction. This was a single center prospective observational study in an academic institution. Fifty adult patients undergoing elective cardiac surgery were included. TTE, TEE and stroke volume measurements pre-cardiopulmonary bypass (CPB) and post-CPB were performed. The variables of interest were anatomical M-mode tricuspid annular plane systolic excursion (AMM-TAPSE), fractional area change (FAC), tricuspid annular velocity (S') and myocardial performance index (MPI). FAC and AMM-TAPSE measured at the mid-esophageal 4 chamber view had substantial agreement with the TTE acquired parameters (Lin's concordance correlation coefficient (CCC) = 0.76, 95%CI 0.59-0.86 and CCC = 0.85, 95%CI 0.76-0.91). S' was significantly underestimated by TEE (CCC = 0.07, 95%CI 0.04-0.19) and MPI showed moderate agreement (CCC = 0.45 95%CI 0.19-0.65). Despite the significant changes in echocardiographic parameters, there were no corresponding changes in stroke volume (SV) or pulmonary artery pulsatility index at the post-CPB period. TEE acquired FAC and AMM-TAPSE had substantial agreement with pre-operative TTE values and no significant differences between the pre-CPB and post-CPB period. Systolic RV echocardiographic parameters decreased post-CPB but this was not accompanied by significant hemodynamic changes.

Genome Editing and Cardiac Regeneration.

Although the field of cardiac regeneration is relatively young, it is progressing rapidly with technological advancements. Genome editing tools are allowing researchers to creatively influence signaling pathways to be able to shed light on them and are important for addressing certain issues and limitations associated with in vitro and in vivo aspects of cardiac regeneration, such as imaging and immune rejection. In this chapter, the pathways involved in cardiac regeneration will be highlighted, and the role of gene-editing tools in endogenous and exogenous approaches to regenerate injured myocardium is discussed.

The multidisciplinary management of a mechanical mitral valve thrombosis in pregnancy: a case report and review of the literature.

Background: The management of anticoagulation for mechanical heart valves during pregnancy poses a unique challenge. Mechanical valve thrombosis is a devastating complication for which surgery is often the treatment of choice. However, cardiac surgery for prosthetic valve dysfunction in pregnant patients confers a high risk of maternofetal morbidity and mortality. Case summary: A 39-year-old woman in her first pregnancy at 30 weeks gestation presented to hospital with a mechanical mitral valve thrombosis despite therapeutic anticoagulation with low-molecular-weight heparin. She underwent an emergent caesarean section followed immediately by a bioprosthetic mitral valve replacement. This occurred after careful planning and organization on the part of a large multidisciplinary team. Discussion: A proactive, rather than reactive, approach to the surgical management of a mechanical valve thrombosis in pregnancy will maximize the chances of successful maternal and fetal outcomes.

Migration despite stabilization of an embolized transcatheter heart valve: A word of caution.

This case report describes an initially stabilized transcatheter heart valve that embolized in the ascending aorta, leading to a postprocedural acute type A aortic dissection.

Alginate-Chitosan Hydrogel Formulations Sustain Baculovirus Delivery and VEGFA Expression Which Promotes Angiogenesis for Wound Dressing Applications.

Hydrogel wound dressings are effective in their ability to provide a wound-healing environment but are limited by their ability to promote later stages of revascularization. Here, a biosafe recombinant baculovirus expressing VEGFA tagged with EGFP is encapsulated in chitosan-coated alginate hydrogels using ionic cross-linking. The VEGFA, delivered by the baculovirus, significantly improves cell migration and angiogenesis to assist with the wound-healing process and revascularization. Moreover, the hydrogels have an encapsulation efficiency of 99.9%, no cytotoxicity, antimicrobial properties, good blood compatibility, promote hemostasis, and enable sustained delivery of baculoviruses over eight days. These hydrogels sustain baculovirus delivery and may have clinical implications in wound dressings or future gene therapy applications.

Snare or Scalpel: Challenges of Intracardiac Cement Embolism Retrieval.

Intracardiac cement embolism after percutaneous vertebroplasty is a rare, but dangerous, complication, and guiding principles for its management are not well described. The management of this present case of intracardiac cement embolism offers insight to facilitate the treatment decision-making process in symptomatic patients requiring extraction.

Synthesis and characterization of peptide conjugated human serum albumin nanoparticles for targeted cardiac uptake and drug delivery.

Congestive heart failure, a prominent cardiovascular disease results primarily from myocardial infarction or ischemia. Milrinone (MRN), a widely used clinical drug for heart failure, improves myocardial contractility and cardiac function through its inotropic and vasodilatory effects. However, lacking target specificity, it exhibits low bioavailability and lower body retention time. Therefore, in this study, angiotensin II (AT1) peptide conjugated human serum albumin nanoparticles (AT1-HSA-MRN-NPs) have been synthesized for targeted delivery of MRN to the myocardium, overexpressing AT1 receptors under heart failure. The NPs were surface functionalized through a covalent conjugation reaction between HSA and AT1. Nanoparticle size was 215.2±4.7 nm and zeta potential -28.8±2.7 mV and cumulative release of MRN was ~72% over 24 hrs. The intracellular uptake of nanoparticles and cell viability was studied in H9c2 cells treated with AT1-MRN-HSA-NPs vs the control non-targeted drug, MRN Lactate under normal, hypoxic and hypertrophic conditions. The uptake of AT1-HSA-MRN-NPs in H9c2 cells was significantly higher as compared to non-targeted nanoparticles, and the viability of H9c2 cells treated with AT1-MRN-HSA-NPs vs MRN Lactate was 73.4±1.4% vs 44.9±1.4%, respectively. Therefore, AT1-HSA-MRN-NPs are safe for in vivo use and exhibit superior targeting and drug delivery characteristics for treatment of heart failure.

Albumin Nanoparticle Formulation for Heart-Targeted Drug Delivery: In Vivo Assessment of Congestive Heart Failure.

Congestive heart failure is a fatal cardiovascular disease resulting in tissue necrosis and loss of cardiac contractile function. Inotropic drugs such as milrinone are commonly used to improve the myocardial contractility and heart function. However, milrinone is associated with severe side effects and lower circulation time. In this article, a novel protein nanoparticle formulation for heart-targeted delivery of milrinone has been designed and tested. The formulation was prepared using albumin protein conjugated with the targeting ligand, angiotensin II peptide to form nanoparticles following the ethanol desolvation method. The formulation was characterized for size, charge, and morphology and tested in a rat model of congestive heart failure to study pharmacokinetics, biodistribution, and efficacy. The overall cardiac output parameters were evaluated comparing the formulation with the control non-targeted drug, milrinone lactate. This formulation exhibited improved pharmacokinetics with a mean retention time of 123.7 min, half-life of 101.3 min, and clearance rate of 0.24 L/(kg*h). The targeted formulation also significantly improved ejection fraction and fractional shortening parameters thus improving cardiac function. This study demonstrates a new approach in delivering inotropic drugs such as milrinone for superior treatment of congestive heart failure.

Postoperative Nosocomial COVID-19 Infection in Cardiac Surgery: An Uncommon Event With High Mortality Rate.

BACKGROUND: The COVID-19 pandemic has had a major impact on cardiac surgery patients. Significant reductions in access to surgical treatment have forced surgeons to prioritise patients and follow strict COVID-19 protocols to protect surgeons, staff, and patients. Adult cardiac surgery and the COVID-19 pandemic: aggressive infection mitigation strategies are necessary in the operating room and surgical recovery. Nosocomial infections among cardiac surgery patients have been reported and are associated with a high mortality rate. As a COVID-19 tertiary care centre and a tertiary cardiac centre, we tried to balance the need to operate on urgent cardiac cases while protecting patients and staff from COVID-19. METHODS: During the first wave of the pandemic, we performed 579 surgeries. We report findings from an outbreak of 4 nosocomial infections. RESULTS: All patients tested negative within 24 hours of surgery or admission. Three patients were positive after surgery, suggesting an overall nosocomial rate during the first wave of 0.5% (3/579). One patient admitted for evaluation tested positive during mass screening. Two of the 4 patients died after respiratory complications. No health care worker (HCW) or family member with direct contact with these patients tested positive for COVID-19. Nosocomial COVID-19 infection is uncommon when adhering to safety protocols. Although uncommon, the mortality rate is high (50%) in our series. CONCLUSIONS: As widespread vaccination of HCWs and high-risk individuals susceptible to COVID-19 is in progress, we suggest that cardiac surgery patients, when feasible, be vaccinated before surgery given this could prevent excess mortality, protect HCWs and reduce resource use.

CONTEXTE: La pandémie de COVID-19 a eu des répercussions importantes sur les patients en chirurgie cardiaque. Les réductions importantes de l'accès aux traitements chirurgicaux ont obligé les chirurgiens à classer les patients par ordre de priorité et à suivre des protocoles COVID-19 rigoureux pour protéger les chirurgiens, le personnel et les patients. En ce qui a trait à la chirurgie cardiaque chez les adultes pendant la pandémie de COVID-19, des stratégies énergiques d'atténuation des infections sont nécessaires en salle d'opération et pendant la convalescence. Des infections nosocomiales ont été signalées chez des patients de chirurgie cardiaque; elles sont associées à un taux de mortalité élevé. Comme notre centre de soins tertiaires traite à la fois des patients atteints de troubles cardiaques et des patients atteints de la COVID-19, nous avons essayé de trouver un équilibre entre la nécessité d'effectuer les opérations cardiaques urgentes et la protection des patients et du personnel contre la COVID-19. MÉTHODOLOGIE: Pendant la première vague de la pandémie, nous avons effectué 579 interventions chirurgicales. Nous rapportons les résultats d'une éclosion de quatre infections nosocomiales. RÉSULTATS: Tous les patients ont obtenu un résultat négatif au test de dépistage dans les 24 heures suivant l'intervention ou l'admission. Trois patients ont obtenu un résultat positif à ce test après l'intervention, ce qui indique un taux global d'infection nosocomiale de 0,5 % (3 / 579) au cours de la première vague. Un patient admis pour évaluation a obtenu un résultat positif au moment du dépistage de masse. Deux des quatre patients sont morts après des complications respiratoires. Aucun travailleur de la santé ou membre de la famille ayant eu un contact direct avec ces patients n'a obtenu un résultat positif au test de dépistage de la COVID-19. L'infection nosocomiale à la COVID-19 est rare quand les protocoles de sécurité sont respectés. Mais même si elle est peu fréquente, le taux de mortalité associé est élevé (50 %) dans notre série. CONCLUSIONS: Alors que la vaccination généralisée des travailleurs de la santé et des personnes à haut risque vulnérables à la COVID-19 est en cours, nous suggérons que les patients en chirurgie cardiaque soient vaccinés avant l'opération, si possible, car cela pourrait prévenir la surmortalité, protéger les travailleurs de la santé et réduire l'utilisation des ressources.

Ex vivo Ikkß ablation rescues the immunopotency of mesenchymal stromal cells from diabetics with advanced atherosclerosis.

AIMS: Diabetes is a conventional risk factor for atherosclerotic cardiovascular disease and myocardial infarction (MI) is the most common cause of death among these patients. Mesenchymal stromal cells (MSCs) in patients with type 2 diabetes mellitus (T2DM) and atherosclerosis have impaired ability to suppress activated T-cells (i.e. reduced immunopotency). This is mediated by an inflammatory shift in MSC-secreted soluble factors (i.e. pro-inflammatory secretome) and can contribute to the reduced therapeutic effects of autologous T2DM and atherosclerosis-MSC post-MI. The signalling pathways driving the altered secretome of atherosclerosis- and T2DM-MSC are unknown. Specifically, the effect of IκB kinase ß (IKKß) modulation, a key regulator of inflammatory responses, on the immunopotency of MSCs from T2DM patients with advanced atherosclerosis has not been studied. METHODS AND RESULTS: MSCs were isolated from adipose tissue obtained from patients with (i) atherosclerosis and T2DM (atherosclerosis+T2DM MSCs, n = 17) and (ii) atherosclerosis without T2DM (atherosclerosis MSCs, n = 17). MSCs from atherosclerosis+T2DM individuals displayed an inflammatory senescent phenotype and constitutively expressed active forms of effectors of the canonical IKKß nuclear factor-κB transcription factors inflammatory pathway. Importantly, this constitutive pro-inflammatory IKKß signature resulted in an altered secretome and impaired in vitro immunopotency and in vivo healing capacity in an acute MI model. Notably, treatment with a selective IKKß inhibitor or IKKß knockdown (KD) (clustered regularly interspaced short palindromic repeats/Cas9-mediated IKKß KD) in atherosclerosis+T2DM MSCs reduced the production of pro-inflammatory secretome, increased survival, and rescued their immunopotency both in vitro and in vivo. CONCLUSIONS: Constitutively active IKKß reduces the immunopotency of atherosclerosis+T2DM MSC by changing their secretome composition. Modulation of IKKß in atherosclerosis+T2DM MSCs enhances their myocardial repair ability.

Human multipotent mesenchymal stromal cells cytokine priming promotes RAB27B-regulated secretion of small extracellular vesicles with immunomodulatory cargo.

BACKGROUND: The paracrine effects of multipotent mesenchymal stromal cells (MSCs) are mediated by their secretome composed by soluble factors (i.e., cytokines, growth factors, hormones) and extracellular vesicles (EVs). EVs promote intercellular communication, and the EV cargoes [e.g., proteins, soluble factors, microRNAs (miRNAs), messenger RNA (mRNA), DNA] reflect the molecular and functional characteristics of their parental cells. MSC-derived EVs (MSC-EVs) are currently evaluated as subcellular therapeutics. A key function of the MSC secretome is its ability to promote immune tolerance (i.e., immunopotency), a property that is enhanced by priming approaches (e.g., cytokines, hypoxia, chemicals) and inversely correlates with the age of the MSC donors. We evaluated mechanisms underlying MSC vesiculation and the effects of inflammation and aging on this process. METHODS: We evaluated the effects of interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) on human adipose-derived MSC: (a) vesiculation (custom RT2 Profiler PCR Array), (b) EV profiles (Nanoparticle Tracking Analysis and Nanoparticle Flow Cytometry), (c) EV cargo (proteomic analysis and Western blot analysis), and (d) immunopotency (standard MSC:CD4 T cell proliferation inhibition assay). We confirmed the role of RAB27B on MSC vesiculation (RAB27B siRNA) and assessed its differential contribution to vesiculation in adult and pediatric MSCs (qPCR). RESULTS: Cytokine priming upregulated RAB27B in adipose-derived MSCs increasing their secretion of exosome-like small EVs (sEVs; < 200 nm) containing two key mediators of immunopotency: A20 and TSG-6. These EVs inhibited T cell proliferation in a dose-dependent manner. RAB27B siRNA inhibited MSC vesiculation. Adipose-derived MSCs isolated from pediatric donors exhibited higher RAB27B expression and secreted more sEVs than adult MSCs. CONCLUSIONS: Cytokine priming is a useful strategy to harvest anti-inflammatory MSC-sEVs for clinical applications. Of relevance, donor age should be considered in the selection of MSC-sEVs for clinical applications.

The Role of Wnt/ß-Catenin Pathway Mediators in Aortic Valve Stenosis.

Aortic valve stenosis (AVS) is a prevailing and life-threatening cardiovascular disease in adults over 75 years of age. However, the molecular mechanisms governing the pathogenesis of AVS are yet to be fully unraveled. With accumulating evidence that Wnt signaling plays a key role in the development of AVS, the involvement of Wnt molecules has become an integral study target in AVS pathogenesis. Thus, we hypothesized that the Wnt/ß-catenin pathway mediators, SFRP2, DVL2, GSK3ß and ß-catenin are dysregulated in patients with AVS. Using immunohistochemistry, Real-Time qPCR and Western blotting, we investigated the presence of SFRP2, GSK-3ß, DVL2, and ß-catenin in normal and stenotic human aortic valves. Markedly higher mRNA and protein expression of GSK-3ß, DVL2, ß-catenin and SFRP2 were found in stenotic aortic valves. This was further corroborated by observation of their abundant immunostaining, which displayed strong immunoreactivity in diseased aortic valves. Proteomic analyses of selective GSK3b inhibition in calcifying human aortic valve interstitial cells (HAVICs) revealed enrichment of proteins involved organophosphate metabolism, while reducing the activation of pathogenic biomolecular processes. Lastly, use of the potent calcification inhibitor, Fetuin A, in calcifying HAVICs significantly reduced the expression of Wnt signaling genes Wnt3a, Wnt5a, Wnt5b, and Wnt11. The current findings of altered expression of canonical Wnt signaling in AVS suggest a possible role for regulatory Wnts in AVS. Hence, future studies focused on targeting these molecules are warranted to underline their role in the pathogenesis of the disease.

Transcatheter valve replacement: a revolution.

Degenerative aortic stenosis is the most common valvular disease worldwide; however, its physiopathology remains poorly understood. Although, developments in prevention of this disease have remained relatively stagnant, the last decade has brought about innovative treatment options incorporating different percutaneous and surgical approaches. These advances have allowed physicians to offer relief to high-risk patients, previously deemed nonsurgical. Increasingly, there is a shift toward offering percutaneous valve replacement to moderate and low-risk patients with aortic stenosis. Enthusiasm for a new treatment option must always be tempered by caution; as defining appropriate patient selection is essential to achieve optimal outcomes.

Parenteral amino acid supplementation with high-dose insulin prevents hypoaminoacidemia during cardiac surgery.

OBJECTIVES: Surgery triggers a stress response that produces insulin resistance and hyperglycemia. During cardiac surgery, the administration of high-dose insulin along with dextrose titration maintains normoglycemia, but dramatically decreases plasma amino acids (AAs) compared with preoperative fasting levels. Hypoaminoacidemia limits protein synthesis and prevents anabolic responses after surgery. We investigated whether parenteral infusion of AAs during and immediately after cardiac surgery would prevent hypoaminoacidemia in patients who receive high-dose insulin therapy. METHODS: Sixteen patients undergoing coronary artery bypass grafting surgery were randomly allocated to receive AAs with % kcal equivalent to either 20% (n = 8) or 35% (n = 8) of their measured resting energy expenditure (REE). Insulin was infused at a constant rate of 5 mU/(kg × min), whereas dextrose was titrated to maintain normoglycemia during and until 5 h after surgery. Plasma AA concentrations were measured at baseline before and after surgery. RESULTS: Compared with the 20% AA group after surgery, AA concentrations were significantly higher in the 35% AA group for 12 of 20 AAs (P < 0.032), including all branched-chain AAs. In the 20% AA group, total essential AAs decreased by 21% and nonessential AAs decreased by 14% after surgery compared with preoperative fasting levels. In contrast, giving 35% AAs prevented this unfavorable decrease in AAs, and in fact allowed for a 23% and 12% increase in essential and nonessential AAs, respectively. CONCLUSIONS: AA supplementation at 35% REE, but not 20% REE, can effectively prevent hypoaminoacidemia caused by high-dose insulin therapy during cardiac surgery.