Evolocumab Treatment in Dyslipidemic Patients Undergoing Coronary Artery Bypass Grafting: One-Year Safety and Efficacy Results.

Background: The inhibition of PCSK9 lowered LDL cholesterol levels, reducing the risk of cardiovascular events. However, the effect on patients who have undergone surgical myocardial revascularization has not yet been evaluated. Methods: From January 2017 to December 2022, 180 dyslipidemic patients who underwent coronary artery bypass were included in the study. Until December 2019, 100 patients optimized therapy with statin ± ezetimibe (SG). Since January 2020, 80 matched patients added treatment with Evolocumab every 2 weeks (EG). All 180 patients were followed-up at 3 and 12 months, comparing outcomes. Results: The two groups are homogenous. At 3 months and 1 year, a significant decrease in the parameter mean levels of LDL cholesterol and total cholesterol is detected in the Evolocumab group compared to the standard group. No mortality was detected in either group. No complications or drug discontinuation were recorded. In the SG group, five patients (5%) suffered a myocardial infarction during the 1-year follow-up. In the EG group, two patients (2.5%) underwent PTCA due to myocardial infarction. There is no significant difference in overall survival according to the new treatment (p-value = 0.9), and the hazard ratio is equal to 0.94 (95% C.I.: [0.16-5.43]; p-value = 0.9397). Conclusions: The use of Evolocumab, which was started immediately after coronary artery bypass graft surgery, significantly reduced LDL cholesterol and total cholesterol levels compared to statin treatment alone and is completely safe. However, at one year of follow-up, this result did not have impact on the reduction in major clinical events.

The Histone Deacetylase Family: Structural Features and Application of Combined Computational Methods.

Histone deacetylases (HDACs) are crucial in gene transcription, removing acetyl groups from histones. They also influence the deacetylation of non-histone proteins, contributing to the regulation of various biological processes. Thus, HDACs play pivotal roles in various diseases, including cancer, neurodegenerative disorders, and inflammatory conditions, highlighting their potential as therapeutic targets. This paper reviews the structure and function of the four classes of human HDACs. While four HDAC inhibitors are currently available for treating hematological malignancies, numerous others are undergoing clinical trials. However, their non-selective toxicity necessitates ongoing research into safer and more efficient class-selective or isoform-selective inhibitors. Computational methods have aided the discovery of HDAC inhibitors with the desired potency and/or selectivity. These methods include ligand-based approaches, such as scaffold hopping, pharmacophore modeling, three-dimensional quantitative structure-activity relationships, and structure-based virtual screening (molecular docking). Moreover, recent developments in the field of molecular dynamics simulations, combined with Poisson-Boltzmann/molecular mechanics generalized Born surface area techniques, have improved the prediction of ligand binding affinity. In this review, we delve into the ways in which these methods have contributed to designing and identifying HDAC inhibitors.

Arrhythmic Mitral Valve Prolapse and Sports Activity: Pathophysiology, Risk Stratification, and Sports Eligibility Assessment.

Although mitral valve prolapse (MVP) is the most prevalent valvular abnormality in Western countries and generally carries a good prognosis, a small subset of patients is exposed to a significant risk of malignant ventricular arrhythmias (VAs) and sudden cardiac death (SCD), the so-called arrhythmic MVP (AMVP) syndrome. Recent work has emphasized phenotypical risk features of severe AMVP and clarified its pathophysiology. However, the appropriate assessment and risk stratification of patients with suspected AMVP remains a clinical conundrum, with the possibility of both overestimating and underestimating the risk of malignant VAs, with the inappropriate use of advanced imaging and invasive electrophysiology study on one hand, and the catastrophic occurrence of SCD on the other. Furthermore, the sports eligibility assessment of athletes with AMVP remains ill defined, especially in the grey zone of intermediate arrhythmic risk. The definition, epidemiology, pathophysiology, risk stratification, and treatment of AMVP are covered in the present review. Considering recent guidelines and expert consensus statements, we propose a comprehensive pathway to facilitate appropriate counseling concerning the practice of competitive/leisure-time sports, envisioning shared decision making and the multidisciplinary "sports heart team" evaluation of borderline cases. Our final aim is to encourage an active lifestyle without compromising patients' safety.

Pathophysiology of Atrial Fibrillation and Approach to Therapy in Subjects Less than 60 Years Old.

Atrial fibrillation (AF) is an arrhythmia that affects the left atrium, cardiac function, and the patients' survival rate. Due to empowered diagnostics, it has become increasingly recognized among young individuals as well, in whom it is influenced by a complex interplay of autoimmune, inflammatory, and electrophysiological mechanisms. Deepening our understanding of these mechanisms could contribute to improving AF management and treatment. Inflammation is a complexly regulated process, with interactions among various immune cell types, signaling molecules, and complement components. Addressing circulating antibodies and designing specific autoantibodies are promising therapeutic options. In cardiomyopathies or channelopathies, the first manifestation could be paroxysmal AF; persistent forms tend not to respond to antiarrhythmic drugs in these conditions. Further research, both in vitro and in vivo, on the use of genomic biotechnology could lead to new therapeutic approaches. Additional triggers that can be encountered in AF patients below 60 years of age are systemic hypertension, overweight, diabetes, and alcohol abuse. The aims of this review are to briefly report evidence from basic science and results of clinical studies that might explain the juvenile burden of the most encountered sustained supraventricular tachyarrhythmias in the general population.

Distinctive phenogroup to differentiate diagnosis of cardiac myxoma vs cardiovascular disease examining blood-based circulating cell biomarkers.

Cardiac myxoma (CM) is a potentially life-threatening disease because frequently asymptomatic or debuts with aspecific manifestations. Definitive diagnosis is established by histopathological assessment including tumor and endothelial cell markers. To derive a specific panel of circulating cells antigenically detectable, pre-surgery peripheral blood samples of CM patients were analyzed. Pre-surgery peripheral blood samples from patients with CM were simultaneously analyzed for Circulating tumor cells (CTCs) and circulating endothelial cells (CECs) that were matched with tumor tissue profiles and with patient-derived xenografts (PDXs) distinguishing tumor regions. Moreover, CECs values in CM patients were further matched with CEC's levels in cardiovascular disease and control subjects. The blood-derived cytological specimens detected at least 1-3 CTCs/ml in 10 tested CM samples (p = 0.0001) showing specific CM features preserved in the central zones of the tumor. The central zone of the primary tumor, supported by a vessel density rate (55 ± 7%), with a proliferative profile of 32 ± 3% and a percentage of Calretininpos cells (p = 0.03), is the principal site of CTCs (r = 00) dissemination. The subsets of endothelial cells recognized in the blood were indifferent to their topological distribution within the tumor and corresponding PDXs. With further refinement and validation in large cohorts, multiparametric liquid biopsies can optimally integrate clinically informative datasets and maximize their utility in pre-surgery evaluation of CM patients. Blood-derived culture's protocol provides a versatile method capable of viable analysis of CTCs of non-hematological rare tumors which conventional antibody-mediated analytical platform is unable to perform. Distinctive blood- based cell phenotype contributes to differentiate CM from other differentials assuring its prompt surgical resection by combining blood-based cell biomarkers integrated with clinically informative datasets.

Renin-angiotensin-aldosterone system inhibition in patients affected by heart failure: efficacy, mechanistic effects and practical use of sacubitril/valsartan. Position Paper of the Italian Society of Cardiology.

Renin-angiotensin-aldosterone system (RAAS) inhibition is a mainstay of the pharmacological treatment of heart failure with reduced ejection fraction (HFrEF). In the last years RAAS blockade has been improved by the introduction of the Angiotensin Receptor-Neprilysin Inhibitor (ARNI) sacubitril/valsartan, that combines RAAS inhibition with the block of neprilysin, boosting the positive effects of natriuretic peptides. The PARADIGM-HF trial demonstrated a significant advantage of sacubitril/valsartan over enalapril on the reduction of cardiovascular (CV) mortality and heart failure hospitalizations rates. Then, several randomized clinical trials and observational studies investigated its role in different clinical settings and its efficacy has been fully recognized in the most recent HFrEF European and USA guidelines. The effects of sacubitril/valsartan on major CV outcomes are associated with reduction of NT-proBNP levels and reverse cardiac remodeling and mitral regurgitation, recognized as one of the mechanistic effects of the drug explaining the favorable prognostic effects. A careful evaluation of patients' clinical profile is relevant to implement the use of ARNI in the clinical practice and to obtain the maximal treatment efficacy. The present Position Paper reports the opinion of the Italian Society of Cardiology on the optimal blockade of the RAAS system in HF patients with the aim of fostering widespread implementation of scientific evidence and practice guidelines in the medical community.

Direct Oral Anticoagulants: From Randomized Clinical Trials to Real-World Clinical Practice.

Direct oral anticoagulants (DOACs) are a more manageable alternative than vitamin K antagonists (VKAs) to prevent stroke in patients with nonvalvular atrial fibrillation and to prevent and treat venous thromboembolism. Despite their widespread use in clinical practice, there are still some unresolved issues on optimizing their use in particular clinical settings. Herein, we reviewed the current clinical evidence on uses of DOACs from pharmacology and clinical indications to safety and practical issues such as drugs and food interactions. Dabigatran is the DOAC most affected by interactions with drugs and food, although all DOACs demonstrate a favorable pharmacokinetic profile. Management issues associated with perioperative procedures, bleeding treatment, and special populations (pregnancy, renal and hepatic impairment, elderly, and oncologic patients) have been discussed. Literature evidence shows that DOACs are at least as effective as VKAs, with a favorable safety profile; data are particularly encouraging in using low doses of edoxaban in elderly patients, and edoxaban and rivaroxaban in the treatment of venous thromboembolism in oncologic patients. In the next year, DOAC clinical indications are likely to be further extended.

Variation in the Association between Antineoplastic Therapies and Venous Thromboembolism in Patients with Active Cancer.

BACKGROUND: Venous thromboembolism (VTE) is a major cause of death in cancer patients. Although patients with cancer have numerous risk factors for VTE, the relative contribution of cancer treatments is unclear. OBJECTIVE: The objective of this study is to evaluate the association between cancer therapies and the risk of VTE. METHODS: From UK Clinical Practice Research Datalink, data on patients with first cancer diagnosis between 2008 and 2016 were extracted along with information on hospitalization, treatments, and cause of death. Primary outcome was active cancer-associated VTE. To establish the independent effects of risk factors, adjusted subhazard ratios (adj-SHR) were calculated using Fine and Gray regression analysis accounting for death as competing risk. RESULTS: Among 67,801 patients with a first cancer diagnosis, active cancer-associated VTE occurred in 1,473 (2.2%). During a median observation time of 1.2 years, chemotherapy, surgery, hormonal therapy, radiation therapy, and immunotherapy were given to 71.1, 37.2, 17.2, 17.5, and 1.4% of patients with VTE, respectively. The active cancers associated with the highest risk of VTE-as assessed by incidence rates-included pancreatic cancer, brain cancer, and metastatic cancer. Chemotherapy was associated with an increased risk of VTE (adj-SHR: 3.17, 95% confidence interval [CI]: 2.76-3.65) while immunotherapy with a not significant reduced risk (adj-SHR: 0.67, 95% CI: 0.30-1.52). There was no association between VTE and radiation therapy (adj-SHR: 0.91, 95% CI: 0.65-1.27) and hormonal therapies. CONCLUSION: VTE risk varies with cancer type. Chemotherapy was associated with an increased VTE risk, whereas with radiation and immunotherapy therapy, an association was not confirmed.

Subcutaneous implantable cardioverter defibrillator in cardiomyopathies and channelopathies.

: Cardiomyopathies and channelopathies are heterogeneous disorders that increase the risk of sudden cardiac death (SCD). Implantable cardioverter-defibrillator (ICD) therapy is safe and effective for preventing SCD in patients at risk for malignant ventricular arrhythmias. Because of the poor positive predictive value of current risk stratification tools, the majority of patients implanted with an ICD will never receive a life-saving therapy but will be exposed to the risk of complications such as device infection, lead failure and inappropriate therapy. Subcutaneous ICD (S-ICD) now constitutes a valuable alternative to conventional transvenous ICD in patients with cardiomyopathies and channelopathies as it provides protection from SCD while avoiding the risks of intravascular lead infection or failure. This may be particularly advantageous for young patients with a very long life expectancy. On the other hand, S-ICD cannot deliver antitachycardia pacing or antibradycardia pacing. The purpose of this article is to review the available evidence and the future perspectives of S-ICD therapy in patients with cardiomyopathies or channelopathies.

Clinical significance of non-vitamin K antagonist oral anticoagulants in the management of atrial fibrillation.

Atrial fibrillation (AF) is the most commonly observed rhythm disorder in clinical practice. It is associated with a high risk of thromboembolic stroke and increased cardiovascular mortality. Vitamin K antagonists (VKAs), the only oral anticoagulants used for thromboembolic prophylaxis in AF patients over the past 60 years, have been effective in reducing thromboembolic stroke, compared with placebo and aspirin, in this group of patients. However, VKAs have a very narrow therapeutic window, so regular monitoring of the therapeutic effect is obligatory for their use. The need for regular assessment of blood anticoagulation often causes dissatisfaction and reduces patients' quality of life. Non-VKA oral anticoagulants (NOACs), such as dabigatran, a direct thrombin inhibitor, and 3 factor Xa inhibitors, namely rivaroxaban, apixaban, and edoxaban, have been developed in recent years and have increased the armamentarium available to the physician for thromboprophylaxis in non-valvular AF (NVAF) patients. This review describes the characteristics of NOACs, analyzing aspects related to their use in the thromboprophylaxis of NVAF patients. It also discusses how to optimize NOAC therapy in specific clinical conditions, such as renal or liver impairment, and concomitant assumption of drugs potentially interfering with NOACs action. Finally, it focuses on NOAC-related bleeding management in the setting of non-cardiac surgery or radiofrequency catheter ablation of NVAF.

The instantaneous wave-free ratio (iFR) for evaluation of non-culprit lesions in patients with acute coronary syndrome and multivessel disease.

BACKGROUND: Adenosine administration is currently required for evaluation of stenosis severity with fractional flow reserve (FFR). The instantaneous wave-free ratio (iFR) was recently introduced as an adenosine-free alternative in patients with stable CAD. The aim of the present study was to replicate the findings of previous iFR studies using an independent calculation algorithm and to evaluate the iFR for the assessment of non-culprit vessels in patients with acute coronary syndrome (ACS). METHODS AND RESULTS: 53 patients with ACS (65%) and at least one non-culprit intermediate lesion and 29 (35%) with stable CAD were included. A total of 123 stenoses were evaluated with both FFR and iFR. Classification match of iFR in ACS was not inferior to stable CAD (79.5% in ACS and 84.4% in CAD; p=0.497). Accordingly, no difference was observed in iFR/FFR correlation between ACS and stable CAD (r=0.66 in ACS vs. r=0.69 in CAD). Overall, a significant correlation was found between iFR and FFR (r=0.68; p<0.001) with a good diagnostic efficiency at ROC analysis (area under the curve: 0.87). In addition, neither the localization of the stenosis within the coronary tree (p=0.147) nor the time interval from the acute event (p=0.550) significantly influenced the concordance of iFR with FFR. CONCLUSIONS: The iFR is a promising method for the assessment of non-culprit lesion severity in patients with acute coronary syndrome.

Single delivery of an adeno-associated viral construct to transfer the CASQ2 gene to knock-in mice affected by catecholaminergic polymorphic ventricular tachycardia is able to cure the disease from birth to advanced age.

BACKGROUND: Catecholaminergic polymorphic ventricular tachycardia is an inherited arrhythmogenic disorder characterized by sudden cardiac death in children. Drug therapy is still insufficient to provide full protection against cardiac arrest, and the use of implantable defibrillators in the pediatric population is limited by side effects. There is therefore a need to explore the curative potential of gene therapy for this disease. We investigated the efficacy and durability of viral gene transfer of the calsequestrin 2 (CASQ2) wild-type gene in a catecholaminergic polymorphic ventricular tachycardia knock-in mouse model carrying the CASQ2(R33Q/R33Q) (R33Q) mutation. METHODS AND RESULTS: We engineered an adeno-associated viral vector serotype 9 (AAV9) containing cDNA of CASQ2 wild-type (AAV9-CASQ2) plus the green fluorescent protein (GFP) gene to infect newborn R33Q mice studied by in vivo and in vitro protocols at 6, 9, and 12 months to investigate the ability of the infection to prevent the disease and adult R33Q mice studied after 2 months to assess whether the AAV9-CASQ2 delivery could revert the catecholaminergic polymorphic ventricular tachycardia phenotype. In both protocols, we observed the restoration of physiological expression and interaction of CASQ2, junctin, and triadin; the rescue of electrophysiological and ultrastructural abnormalities in calcium release units present in R33Q mice; and the lack of life-threatening arrhythmias. CONCLUSIONS: Our data demonstrate that viral gene transfer of wild-type CASQ2 into the heart of R33Q mice prevents and reverts severe manifestations of catecholaminergic polymorphic ventricular tachycardia and that this curative effect lasts for 1 year after a single injection of the vector, thus posing the rationale for the design of a clinical trial.

The usual suspects in sudden cardiac death of the young: a focus on inherited arrhythmogenic diseases.

Up to 14,500 young individuals die suddenly every year in Europe of cardiac pathologies. The majority of these tragic events are related to a group of genetic defects that predispose the development of malignant arrhythmias (inherited arrhythmogenic diseases [IADs]). IADs include both cardiomyopathies (hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy) and channelopathies (long QT syndrome, short QT syndrome, Brugada syndrome and catecholaminergic polymorphic ventricular tachycardia). Every time an IAD is identified in a patient, other individuals in his/her family may be at risk of cardiac events. However; if a timely diagnosis is made, simple preventative measures may be applied. Genetic studies play a pivotal role in the diagnosis of IADs and may help in the management of patients and their relatives.

Novel insight into the natural history of short QT syndrome.

OBJECTIVES: This study intends to gain further insights into the natural history, the yield of familial and genetic screening, and the arrhythmogenic mechanisms in the largest cohort of short QT syndrome (SQTS) patients described so far. BACKGROUND: SQTS is a rare genetic disorder associated with life-threatening arrhythmias, and its natural history is incompletely ascertained. METHODS: Seventy-three SQTS patients (84% male; age, 26 ± 15 years; corrected QT interval, 329 ± 22 ms) were studied, and 62 were followed for 60 ± 41 months (median, 56 months). RESULTS: Cardiac arrest (CA) was the most frequent presenting symptom (40% of probands; range, <1 month to 41 years). The rate of CA was 4% in the first year of life and 1.3% per year between 20 and 40 years; the probability of a first occurrence of CA by 40 years of age was 41%. Despite the male predominance, female patients had a risk profile superimposable to that of men (p = 0.49). The yield of genetic screening was low (14%), despite familial disease being present in 44% of kindreds. A history of CA was the only predictor of recurrences at follow-up (p < 0.0000001). Two patterns of onset of ventricular fibrillation were observed and were reproducible in patients with multiple occurrences of CA. Arrhythmias occurred mainly at rest. CONCLUSIONS: SQTS is highly lethal; CA is often the first manifestation of the disease with a peak incidence in the first year of life. Survivors of CA have a high CA recurrence rate; therefore, implantation of a defibrillator is strongly recommended in this group of patients.

MicroRNA-1 downregulation increases connexin 43 displacement and induces ventricular tachyarrhythmias in rodent hypertrophic hearts.

Downregulation of the muscle-specific microRNA-1 (miR-1) mediates the induction of pathologic cardiac hypertrophy. Dysfunction of the gap junction protein connexin 43 (Cx43), an established miR-1 target, during cardiac hypertrophy leads to ventricular tachyarrhythmias (VT). However, it is still unknown whether miR-1 and Cx43 are interconnected in the pro-arrhythmic context of hypertrophy. Thus, in this study we investigated whether a reduction in the extent of cardiac hypertrophy could limit the pathological electrical remodeling of Cx43 and the onset of VT by modulating miR-1 levels. Wistar male rats underwent mechanical constriction of the ascending aorta to induce pathologic left ventricular hypertrophy (LVH) and afterwards were randomly assigned to receive 10mg/kg valsartan, VAL (LVH+VAL) delivered in the drinking water or placebo (LVH) for 12 weeks. Sham surgery was performed for control groups. Programmed ventricular stimulation reproducibly induced VT in LVH compared to LVH+VAL group. When compared to sham controls, rats from LVH group showed a significant decrease of miR-1 and an increase of Cx43 expression and its ERK1/2-dependent phosphorylation, which displaces Cx43 from the gap junction. Interestingly, VAL administration to rats with aortic banding significantly reduced cardiac hypertrophy and prevented miR-1 down-regulation and Cx43 up-regulation and phosphorylation. Gain- and loss-of-function experiments in neonatal cardiomyocytes (NCMs) in vitro confirmed that Cx43 is a direct target of miR-1. Accordingly, in vitro angiotensin II stimulation reduced miR-1 levels and increased Cx43 expression and phosphorylation compared to un-stimulated NCMs. Finally, in vivo miR-1 cardiac overexpression by an adenoviral vector intra-myocardial injection reduced Cx43 expression and phosphorylation in mice with isoproterenol-induced LVH. In conclusion, miR-1 regulates Cx43 expression and activity in hypertrophic cardiomyocytes in vitro and in vivo. Treatment of pressure overload-induced myocyte hypertrophy reduces the risk of life-threatening VT by normalizing miR-1 expression levels with the consequent stabilization of Cx43 expression and activity within the gap junction.

MicroRNA-133 controls vascular smooth muscle cell phenotypic switch in vitro and vascular remodeling in vivo.

RATIONALE: MicroRNA (miR)-1 and -133 play a crucial role in skeletal and cardiac muscle biology and pathophysiology. However, their expression and regulation in vascular cell physiology and disease is currently unknown. OBJECTIVE: The aim of the present study was to evaluate the role, if any, of miR-1 and miR-133 in vascular smooth muscle cell (VSMC) phenotypic switch in vitro and in vivo. METHODS AND RESULTS: We demonstrate here that miR-133 is robustly expressed in vascular smooth muscle cells (VSMCs) in vitro and in vivo, whereas miR-1 vascular levels are negligible. miR-133 has a potent inhibitory role on VSMC phenotypic switch in vitro and in vivo, whereas miR-1 does not have any relevant effect per se. miR-133 expression is regulated by extracellular signal-regulated kinase 1/2 activation and is inversely correlated with VSMC growth. Indeed, miR-133 decreases when VSMCs are primed to proliferate in vitro and following vascular injury in vivo, whereas it increases when VSMCs are coaxed back to quiescence in vitro and in vivo. miR-133 loss- and gain-of-function experiments show that miR-133 plays a mechanistic role in VSMC growth. Accordingly, adeno-miR-133 reduces but anti-miR-133 exacerbates VSMC proliferation and migration in vitro and in vivo. miR-133 specifically suppresses the transcription factor Sp-1 expression in vitro and in vivo and through Sp-1 repression regulates smooth muscle gene expression. CONCLUSIONS: Our data show that miR-133 is a key regulator of vascular smooth muscle cell phenotypic switch in vitro and in vivo, suggesting its potential therapeutic application for vascular diseases.

Proteomics reveals high levels of vitamin D binding protein in myocardial infarction.

The pathogenic mechanisms underlying cardiovascular diseases involve significant alterations in myocardial gene and protein expression. Proteomics analysis can define new protein and peptide changes associated with cardiac pathology, including myocardial infarction. The aim of the present study was to analyze serum proteome of patients with ST-Elevation myocardial infarction (STEMI). Serum samples were collected from STEMI patients (age 65.0+/-10.3) at 5.3+/-2.7 hours after the onset of typical chest pain and before initiating standard therapy. Ten age- and sex-matched donors were used as controls. The samples were albumin- and IgG-depleted. Isotope-coded affinity tag method was employed to label cysteine residues and liquid chromatography-Tandem Mass Spectrometry analysis was performed to measure the labeled proteins. Our proteomic approach identified increased levels of vitamin D-binding protein precursor (VDB) in the serum of STEMI patients when compared to control donors. Western blot analysis confirmed the increase in VDB protein in STEMI patients. Moreover, fresh thrombotic plaques, obtained during primary angioplasty, showed high expression of VDB protein. Mechanistically, VDB protein reduces platelet aggregation and prolongs coagulation time ex vivo.

Differential regulation of vascular smooth muscle and endothelial cell proliferation in vitro and in vivo by cAMP/PKA-activated p85alphaPI3K.

cAMP inhibits proliferation in most cell types, triggering different and sometimes opposing molecular pathways. p85alpha (phosphatidylinositol 3-kinase regulatory subunit) is phosphorylated by cAMP/PKA in certain cell lineages, but its effects on vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) are unknown. In the present study, we evaluated 1) the role of p85alpha in the integration of cAMP/PKA-dependent signaling on the regulation of VSMC and EC growth in vitro; and 2) the effects of PKA-modified p85alpha on neointimal hyperplasia and endothelial healing after balloon injury in vivo. Plasmid constructs carrying wild-type and PKA-modified p85alpha were employed in VSMCs and ECs in vitro and after balloon injury in rat carotid arteries in vivo. cAMP/PKA reduced VSMC proliferation through p85alpha phosphorylation. Transfected PKA-activated p85alpha binds p21ras, reducing ERK1/2 activation and VSMC proliferation in vitro. In contrast, EC proliferation inhibition by cAMP is independent from PKA modification of p85alpha and ERK1/2 inhibition; indeed, PKA-activated p85alpha did not inhibit per se ERK1/2 activation and proliferation in ECs in vitro. Interestingly, cAMP reduced both VSMC and EC apoptotic death through p85alpha phosphorylation. Accordingly, PKA-activated p85alpha triggered Akt activation, reducing both VSMC and EC apoptosis in vitro. Finally, compared with controls, vascular gene transfer of PKA-activated p85alpha significantly reduced neointimal formation after balloon injury in rats, without inhibiting endothelial regeneration of the injured arterial segment. In conclusions, PKA-activated p85alpha integrates cAMP/PKA signaling differently in VSMCs and ECs. By reducing neointimal hyperplasia without inhibiting endothelial regeneration, it exerts a protective effect against restenosis after balloon injury.

Extracellular superoxide dismutase is a growth regulatory mediator of tissue injury recovery.

Extracellular superoxide dismutase (SOD3) gene therapy has been shown to attenuate tissue damages and to improve the recovery of the tissue injuries, but the cellular events delivering the therapeutic response of the enzyme are not well defined. In the current work, we overexpressed SOD3 in rat hindlimb ischemia model to study the signal transduction and injury healing following the sod3 gene transfer. The data suggest a novel sod3 gene transfer-derived signal transduction cascade through Ras-Mek-Erk mitogenic pathway leading to activation of AP1 and CRE transcription factors, increased vascular endothelial growth factor (VEGF)-A and cyclin D1 expression, increased cell proliferation, and consequently improved metabolic functionality of the injured tissue. Increased cell proliferation could explain the improved metabolic performance and the healing of the tissue damages after the sod3 gene transfer. The present data is a novel description of the molecular mechanism of SOD3-mediated recovery of tissue injury and suggests a new physiological role for SOD3 as a Ras regulatory molecule in signal transduction.