Myocardial sodium-glucose cotransporter 2 expression and cardiac remodelling in patients with severe aortic stenosis: The BIO-AS study.

AIM: Cardiac remodelling plays a major role in the prognosis of patients with aortic stenosis (AS) and could impact the benefits of aortic valve replacement. Our study aimed to evaluate the expression of sodium-glucose cotransporter 2 (SGLT2) gene and protein in patients with severe AS stratified in high gradient (HG) and low flow-low gradient (LF-LG) AS and its association with cardiac functional impairments. METHODS AND RESULTS: Gene expression and protein levels of main biomarkers of cardiac fibrosis (galectin-3, sST2, serpin-4, procollagen type I amino-terminal peptide, procollagen type I carboxy-terminal propeptide, collagen, transforming growth factor [TGF]-ß), inflammation (growth differentiation factor-15, interleukin-6, nuclear factor-κB [NF-κB]), oxidative stress (superoxide dismutase 1 [SOD1] and 2 [SOD2]), and cardiac metabolism (sodium-hydrogen exchanger, peroxisome proliferator-activated receptor [PPAR]-α, PPAR-γ, glucose transporter 1 [GLUT1] and 4 [GLUT4]) were evaluated in blood samples and heart biopsies of 45 patients with AS. Our study showed SGLT2 gene and protein hyper-expression in patients with LF-LG AS, compared to controls and HG AS (p < 0.05). These differences remained significant even after adjusting for age, gender, body mass index, history of diabetes mellitus, arterial hypertension, and coronary artery disease. SGLT2 gene expression was positively correlated with: (i) TGF-ß (r = 0.72, p < 0.001) and collagen (r = 0.73, p < 0.001) as markers of fibrosis; (ii) NF-κB (r = 0.36, p < 0.01) and myocardial interleukin-6 (r = 0.68, p < 0.001) as markers of inflammation: (iii) SOD2 (r = -0.38, p < 0.006) as a marker of oxidative stress; (iv) GLUT4 (r = 0.33, p < 0.02) and PPAR-α (r = 0.36, p < 0.01) as markers of cardiac metabolism. CONCLUSION: In patients with LF-LG AS, SGLT2 gene and protein were hyper-expressed in cardiomyocytes and associated with myocardial fibrosis, inflammation, and oxidative stress.

Mechanical heart valves and oral anticoagulation: a survey of the Italian Society of Cardiac Surgery.

In the latest European guidelines for the management of valvular heart disease, mechanical valve prostheses maintain a strategic role, particularly for certain patient subsets and age groups. Despite the high number of devices implanted in clinical practice, particularly in non-European and North American regions, current scientific literature and debate seem to suggest a limited use of mechanical heart valves. The cardiac surgery community seems to be highly interested in biological and transcatheter valve prostheses but less interested in mechanical heart valves, including possible strategies for self-management of anticoagulation therapy. In this respect, the Italian Society of Cardiac Surgery (SICCH), in particular the Italian Group of Research for Outcome in Cardiac Surgery (GIROC), has promoted a survey among its members to stimulate the interest in this topic and express their opinion on this issue that, due to the prevalence of the affected population and the new treatment options for improving patients' quality of life, should be more appraised and debated in the cardiac surgery community. The recorded results, obtained on the answers to 111 questionnaires, seem to divide the specialists into 'pros' and 'contras' on a useful tool for the entire cardiac surgery community. For this reason, SICCH proposes in conclusion to declare its unified and institutional opinion on this topic.

[Choosing a tailored prosthetic valve in cardiac surgery: what is the current role of mechanical prostheses?] / Il ruolo delle protesi valvolari meccaniche oggi. Dalla letteratura alla situazione italiana.

The choice of the mechanical/biological heart valve prosthesis is a topic currently debated in the light of the transcatheter prosthetic models and the results obtained/expected with the new biological valve models. Consequently, it seems that increasingly younger patients would be indicated for an implantation of a biological prosthesis. This is also in order to improve the quality of life of patients who want to avoid oral anticoagulant therapy. On the other hand, the guidelines for the treatment of heart valve disease assign a central role to the use of mechanical valve prostheses, particularly for certain patient subsets and age groups. This means that mechanical prostheses are still widely used worldwide, especially in non-European or North American regions. The cardiac surgery community therefore seems to be very interested in biological prostheses and transcatheter implants and scarcely interested in mechanical prostheses, including possible strategies for self-management of anticoagulant therapy. Recently, the Italian Society of Cardiac Surgery promoted a survey among its members to stimulate interest in the cardiac surgery community. This review article aims to summarize the most current results recorded with the use of mechanical prostheses and possible strategies, especially for the management of oral anticoagulant therapy, which can improve the patient's quality of life.

An Unusual Case of a Double Tricuspid and Mitral Valves Infective Endocarditis Complicated by Multiple Septic Embolisms Secondary to an Atrial Septal Defect: A Case Report and Review of Literature.

Multivalvular endocarditis (MVE) is an uncommon infection that mostly involves mitral and aortic valves, and it is related to a higher risk of congestive heart failure and a higher mortality. We described a case of a bilateral MVE and performed a review of the literature on similar clinical cases. We reported an unusual case of a 68-year-old male patient with a tricuspid and mitral infective endocarditis due to a methicillin-resistant Staphylococcus aureus complicated by multiple right- and left-sided septic embolization (lungs, brain, spleen, L2-L3 vertebral bones) due to an unknown atrial septal defect identified and repaired during cardiac surgery. Despite the severity of the clinical case, the patient experienced a good clinical outcome also thanks to a multidisciplinary approach. We identified 21 case reports describing bilateral MVE. A multidisciplinary approach is essential in the management of valve diseases to improve the prognosis of patients, especially in bilateral MVE.

A Mouse Model of Dilated Cardiomyopathy Produced by Isoproterenol Acute Exposure Followed by 5-Fluorouracil Administration.

Appropriate dilated cardiomyopathy (DCM) animal models are highly desirable considering the pathophysiological and clinical heterogeneity of DCM. Genetically modified mice are the most widely and intensively utilized research animals for DCM. However, to translate discoveries from basic science into new and personalized medical applications, research in non-genetically based DCM models remains a key issue. Here, we characterized a mouse model of non-ischemic DCM induced by a stepwise pharmacologic regime of Isoproterenol (ISO) high dose bolus followed by a low dose systemic injection of the chemotherapy agent, 5-Fluorouracil (5-FU). C57BL/6J mice were injected with ISO and, 3 days after, were randomly assigned to saline or 5-FU. Echocardiography and a strain analysis show that ISO + 5FU in mice induces progressive left ventricular (LV) dilation and reduced systolic function, along with diastolic dysfunction and a persistent global cardiac contractility depression through 56 days. While mice treated with ISO alone recover anatomically and functionally, ISO + 5-FU causes persistent cardiomyocyte death, ensuing in cardiomyocyte hypertrophy through 56 days. ISO + 5-FU-dependent damage was accompanied by significant myocardial disarray and fibrosis along with exaggerated oxidative stress, tissue inflammation and premature cell senescence accumulation. In conclusions, a combination of ISO + 5FU produces anatomical, histological and functional cardiac alterations typical of DCM, representing a widely available, affordable, and reproducible mouse model of this cardiomyopathy.

Cellular and Molecular Mechanisms Underlying Tricuspid Valve Development and Disease.

Tricuspid valve (TV) disease is highly prevalent in the general population. For ages considered "the forgotten valve" because of the predominant interest in left-side valve disease, the TV has now received significant attention in recent years, with significant improvement both in diagnosis and in management of tricuspid disease. TV is characterized by complex anatomy, physiology, and pathophysiology, in which the right ventricle plays a fundamental role. Comprehensive knowledge of molecular and cellular mechanisms underlying TV development, TV disease, and tricuspid regurgitation-related right-ventricle cardiomyopathy is necessary to enhance TV disease understanding to improve the ability to risk stratify TR patients, while also predicting valve dysfunction and/or response to tricuspid regurgitation treatment. Scientific efforts are still needed to eventually decipher the complete picture describing the etiopathogenesis of TV and TV-associated cardiomyopathy, and future advances to this aim may be achieved by combining emerging diagnostic imaging modalities with molecular and cellular studies. Overall, basic science studies could help to streamline a new coherent hypothesis underlying both the development of TV during embryogenesis and TV-associated disease and its complications in adult life, providing the conceptual basis for the ultimate and innovative field of valve repair and regeneration using tissue-engineered heart valves.

The Novel Role of Noncoding RNAs in Modulating Platelet Function: Implications in Activation and Aggregation.

It is currently believed that plaque complication, with the consequent superimposed thrombosis, is a key factor in the clinical occurrence of acute coronary syndromes (ACSs). Platelets are major players in this process. Despite the considerable progress made by the new antithrombotic strategies (P2Y12 receptor inhibitors, new oral anticoagulants, thrombin direct inhibitors, etc.) in terms of a reduction in major cardiovascular events, a significant number of patients with previous ACSs treated with these drugs continue to experience events, indicating that the mechanisms of platelet remain largely unknown. In the last decade, our knowledge of platelet pathophysiology has improved. It has been reported that, in response to physiological and pathological stimuli, platelet activation is accompanied by de novo protein synthesis, through a rapid and particularly well-regulated translation of resident mRNAs of megakaryocytic derivation. Although the platelets are anucleate, they indeed contain an important fraction of mRNAs that can be quickly used for protein synthesis following their activation. A better understanding of the pathophysiology of platelet activation and the interaction with the main cellular components of the vascular wall will open up new perspectives in the treatment of the majority of thrombotic disorders, such as ACSs, stroke, and peripheral artery diseases before and after the acute event. In the present review, we will discuss the novel role of noncoding RNAs in modulating platelet function, highlighting the possible implications in activation and aggregation.

Current Views on Infective Endocarditis: Changing Epidemiology, Improving Diagnostic Tools and Centering the Patient for Up-to-Date Management.

Infective endocarditis (IE) is a rare but potentially life-threatening disease, sometimes with longstanding sequels among surviving patients. The population at high risk of IE is represented by patients with underlying structural heart disease and/or intravascular prosthetic material. Taking into account the increasing number of intravascular and intracardiac procedures associated with device implantation, the number of patients at risk is growing too. If bacteremia develops, infected vegetation on the native/prosthetic valve or any intracardiac/intravascular device may occur as the final result of invading microorganisms/host immune system interaction. In the case of IE suspicion, all efforts must be focused on the diagnosis as IE can spread to almost any organ in the body. Unfortunately, the diagnosis of IE might be difficult and require a combination of clinical examination, microbiological assessment and echocardiographic evaluation. There is a need of novel microbiological and imaging techniques, especially in cases of blood culture-negative. In the last few years, the management of IE has changed. A multidisciplinary care team, including experts in infectious diseases, cardiology and cardiac surgery, namely, the Endocarditis Team, is highly recommended by the current guidelines.

Streptozotocin-Induced Type 1 and 2 Diabetes Mellitus Mouse Models Show Different Functional, Cellular and Molecular Patterns of Diabetic Cardiomyopathy.

The main cause of morbidity and mortality in diabetes mellitus (DM) is cardiovascular complications. Diabetic cardiomyopathy (DCM) remains incompletely understood. Animal models have been crucial in exploring DCM pathophysiology while identifying potential therapeutic targets. Streptozotocin (STZ) has been widely used to produce experimental models of both type 1 and type 2 DM (T1DM and T2DM). Here, we compared these two models for their effects on cardiac structure, function and transcriptome. Different doses of STZ and diet chows were used to generate T1DM and T2DM in C57BL/6J mice. Normal euglycemic and nonobese sex- and age-matched mice served as controls (CTRL). Immunohistochemistry, RT-PCR and RNA-seq were employed to compare hearts from the three animal groups. STZ-induced T1DM and T2DM affected left ventricular function and myocardial performance differently. T1DM displayed exaggerated apoptotic cardiomyocyte (CM) death and reactive hypertrophy and fibrosis, along with increased cardiac oxidative stress, CM DNA damage and senescence, when compared to T2DM in mice. T1DM and T2DM affected the whole cardiac transcriptome differently. In conclusion, the STZ-induced T1DM and T2DM mouse models showed significant differences in cardiac remodeling, function and the whole transcriptome. These differences could be of key relevance when choosing an animal model to study specific features of DCM.

Long-Term Outcome of Infective Endocarditis Involving Cardiac Implantable Electronic Devices: Impact of Comorbidities and Lead Extraction.

(1) Background: Management of cardiac implantable electronic device-related infective endocarditis (CIED-IE) hinges on complete hardware removal. We assessed whether long-term prognosis is affected by device removal, considering baseline patient comorbid conditions; (2) Methods: A total of 125 consecutive patients hospitalized for CIED-IE were included in this retrospective analysis. Outcomes were in-hospital, one-year, and long-term mortality. There were 109 patients who underwent device removal, 91 by transvenous lead extraction (TLE) and 18 by open heart surgery (OHS); (3) Results: TLE translated into lower hospital mortality (4.4% vs. 22.5% with OHS; p = 0.03). Septic pulmonary embolism was the only independent predictor of in-hospital mortality (OR:7.38 [1.49-36.6], p = 0.013). One-year mortality was in contrast independently associated to tricuspid valve involvement (p = 0.01) and Charlson comorbidity index (CCI, p = 0.039), but not the hardware removal modality. After a median follow-up of 41 months, mortality rose to 24%, and was significantly influenced only by CCI. Specifically, patients with a higher CCI who were also treated with TLE showed a survival rate not significantly different from those managed with medical therapy only; (4) Conclusions: In CIED-IE, TLE is the strategy of choice for hardware removal, improving early outcomes. Long-term benefits of TLE are lessened by comorbidities. In cases of CIED-IE with high CCI, a more conservative approach might be an option.

Diabetes-Induced Cellular Senescence and Senescence-Associated Secretory Phenotype Impair Cardiac Regeneration and Function Independently of Age.

Diabetes mellitus (DM) affects the biology of multipotent cardiac stem/progenitor cells (CSCs) and adult myocardial regeneration. We assessed the hypothesis that senescence and senescence-associated secretory phenotype (SASP) are main mechanisms of cardiac degenerative defect in DM. Accordingly, we tested whether ablation of senescent CSCs would rescue the cardiac regenerative/reparative defect imposed by DM. We obtained cardiac tissue from nonaged (50- to 64-year-old) patients with type 2 diabetes mellitus (T2DM) and without DM (NDM) and postinfarct cardiomyopathy undergoing cardiac surgery. A higher reactive oxygen species production in T2DM was associated with an increased number of senescent/dysfunctional T2DM-human CSCs (hCSCs) with reduced proliferation, clonogenesis/spherogenesis, and myogenic differentiation versus NDM-hCSCs in vitro. T2DM-hCSCs showed a defined pathologic SASP. A combination of two senolytics, dasatinib (D) and quercetin (Q), cleared senescent T2DM-hCSCs in vitro, restoring their expansion and myogenic differentiation capacities. In a T2DM model in young mice, diabetic status per se (independently of ischemia and age) caused CSC senescence coupled with myocardial pathologic remodeling and cardiac dysfunction. D + Q treatment efficiently eliminated senescent cells, rescuing CSC function, which resulted in functional myocardial repair/regeneration, improving cardiac function in murine DM. In conclusion, DM hampers CSC biology, inhibiting CSCs' regenerative potential through the induction of cellular senescence and SASP independently from aging. Senolytics clear senescence, abrogating the SASP and restoring a fully proliferative/differentiation-competent hCSC pool in T2DM with normalization of cardiac function.

Effects of Sodium-Glucose Transporter 2 Inhibitors (SGLT2-I) in Patients With Ischemic Heart Disease (IHD) Treated by Coronary Artery Bypass Grafting via MiECC: Inflammatory Burden, and Clinical Outcomes at 5 Years of Follow-Up.

Introduction: Minimally invasive extracorporeal circulation (MiECC) reduced inflammatory burden, leading to best clinical outcomes in patients treated with coronary artery bypass grafting (CABG). Despite this, the patients with type 2 diabetes mellitus (T2DM) vs those without T2DM (non-T2DM) have a worse prognosis, caused by over-inflammation and modulated by sodium-glucose transporter 2 receptors. However, we evaluated the inflammatory burden and clinical outcomes in non-T2DM vs T2DM patients under sodium-glucose transporter 2 inhibitors (SGLT2-I users) vs non-SGLT2-I users at 5 years of follow-up post-CABG via MiECC. Materials and methods: In a multicenter study, we screened consecutive patients with indications to receive CABG. The study endpoints were the inflammatory burden (circulating serum levels of tumor necrosis factor-alpha (TNF-α), interleukin 1 and 6 (IL-1 and IL-6), C-reactive protein (CRP), and leucocytes count) and the clinical outcomes at follow-up of 5 years in non-T2DM vs SGLT2-I users, in non-T2DM vs non-SGLT2-I users, and SGLT2-I users vs non-SGLT2-I users. Results: At baseline, and at one year and 5 years of follow-up, the non-T2DM vs SGLT2-I users, non-T2DM vs non-SGLT2-I users, and SGLT2-I users vs non-SGLT2-I users had the lowest values of IL-1, IL-6, and TNF-α (p < 0.05). At one year of follow-up, SGLT2-I users vs non-T2DM and non-SGLT2-I users vs non-T2DM users had a higher rate of all deaths, cardiac deaths, re-myocardial infarction, repeat revascularization, and stroke, and of the composite endpoint (p < 0.05). In a multivariate Cox regression analysis, the composite endpoint was predicted by IL-1 [2.068 (1.367-3.129)], TNF-α [1.989 (1.081-2.998)], and SGLT2-I [0.504 (0.078-0.861)]. Conclusion: In T2DM patients, the SGLT2-I significantly reduced the inflammatory burden and ameliorated clinical outcomes at 5 years of follow-up post-CABG via MiECC.

Metformin Therapy Effects on the Expression of Sodium-Glucose Cotransporter 2, Leptin, and SIRT6 Levels in Pericoronary Fat Excised from Pre-Diabetic Patients with Acute Myocardial Infarction.

BACKGROUND AND PURPOSE: pericoronary fat over-inflammation might lead to the development and destabilization of coronary plaque in patients with pre-diabetes (PDM). Notably, pericoronary fat could over-express the sodium-glucose cotransporter 2 (SGLT2) and leptin, along with decreased sirtuin 6 (SIRT6) expression in PDM vs. normoglycemic (NG) patients undergoing coronary artery bypass grafting (CABG) for acute myocardial infarction (AMI). However, in the current study, we evaluated inflammatory markers, SGLT2, SIRT6, and leptin levels in pericoronary fat and, subsequently, 12-month prognosis comparing PDM to NG subjected to CABG for AMI. In addition, we evaluated in PDM patients the effects of metformin therapy on SIRT6 expression, leptin, and SGLT2 levels, and assessed its beneficial effect on nitrotyrosine and inflammatory cytokine levels. METHODS: we studied AMI patients referred for CABG, divided into PDM and NG-patients. PDM patients were divided into never-metformin users and metformin users. Finally, we evaluated major adverse cardiac events (MACE) at a 12-month follow-up. RESULTS: the MACE was 9.1% in all PDM and 3% in NG patients (p < 0.05). Metformin users presented a significantly lower MACE rate in PDM than never-metformin users (p < 0.05). PDM showed higher inflammatory cytokines, 3-nitrotyrosine levels, SGLT2, and leptin content, and decreased SIRT6 protein levels in pericoronary fat compared to NG-patients (p < 0.05). PDM never-metformin-users showed higher SGLT2 and leptin levels in pericoronary fat than current-metformin-users (p < 0.05). CONCLUSIONS: metformin therapy might ameliorate cardiovascular outcomes by reducing inflammatory parameters, SGLT2, and leptin levels, and finally improving SIRT6 levels in AMI-PDM patients treated with CABG.

Cardiac surgery practice during the COVID-19 outbreak: a regionwide survey.

BACKGROUND: Health systems worldwide have been overburdened by the "COVID-19 surge". Consequently, strategies to remodulate non-COVID medical and surgical care had to be developed. Knowledge of the impact of COVID surge on cardiac surgery practice is mainstem. Present study aims to evaluate the regional practice pattern during lockdown in Campania. METHODS: A multicenter regional observational 26-question survey was conducted, including all adult cardiac surgery units in Campania, Italy, to assess how surgical practice has changed during COVID-19 national lockdown. RESULTS: All centers adopted specific protocols for screening patients and personnel. A significant reduction in the number of dedicated intensive care unit (ICU) beds (-30.0%±38.1%, range: 0-100%) and cardiac operating rooms (-22.2%±26.4%, range: 0-50%) along with personnel relocation to other departments was disclosed (anesthesiologists -5.8%±11.1%, range: 0-33.3%; perfusionists -5.6%±16.7%, range: 0-50%; nurses -4.8%±13.2%, range: 0-40%; cardiologists -3.2%±9.5%, range: 0-28.6%). Cardiac surgeons were never reallocated to other services. Globally, we witnessed dramatically lower adult cardiac surgery case volumes (335 vs. 667 procedures, P<0.001), as institutions and surgeons followed guidelines to curtail non-urgent operations. CONCLUSIONS: This regional survey demonstrates major changes in practice as a response to the COVID-19 pandemic. In this respect, this experience might lead to the development of permanent systems-based plans for future pandemic and may effectively help policy decision making when prioritizing healthcare resource reallocation during and after the pandemic.

Microbiota thrombus colonization may influence athero-thrombosis in hyperglycemic patients with ST segment elevation myocardialinfarction (STEMI). Marianella study.

OBJECTIVES: We examined the association of the coronary thrombus microbiota and relative metabolites with major adverse cardiovascular events (MACE) in hyperglycemic patients with ST segment elevation myocardial infarction (STEMI). BACKGROUND: Hyperglycemia during STEMI may affect both development and progression of coronary thrombus via gut and thrombus microbiota modifications. METHODS: We undertook an observational cohort study of 146 first STEMI patients treated with primary percutaneous coronary intervention (PPCI) and thrombus-aspiration (TA). Patients were clustered, based on admission blood glucose levels, in hyperglycemic (≥140 mg/dl) and normoglycemic (<140 mg/dl). We analyzed gut and thrombus microbiota in all patients. Moreover, we assessed TMAO, CD40L and von Willebrand Factor (vWF) in coronary thrombi. Cox regressions were used for the association between Prevotellaspp. and TMAO terziles and MACE. MACE endpoint at 1 year included death, re-infarction, unstable angina. RESULTS: In fecal and thrombus samples, we observed a significantly different prevalence of both Prevotellaspp. and Alistipesspp. between patients with hyperglycemia (n = 56) and those with normal glucose levels (n = 90). The abundance of Prevotella increased in hyperglycemic vs normoglycemic patients whereas the contrary was observed for Alistipes. Interestingly, in coronary thrombus, the content of Prevotella was associated with admission blood glucose levels (p < 0.01), thrombus dimensions (p < 0.01), TMAO, CDL40 (p < 0.01) and vWF (p < 0.01) coronary thrombus contents. Multivariate Cox-analysis disclosed a reduced survival in patients with high levels of Prevotella and TMAO in coronary thrombus as compared to patients with low levels of Prevotella and TMAO, after 1-year follow up. CONCLUSIONS: Hyperglycemia during STEMI may increase coronary thrombus burden via gut and thrombus microbiota dysbiosis characterized by an increase of Prevotella and TMAO content in thrombi. CLINICAL TRIAL REGISTRATION: NCT03439592. September 30, 2016. Ethic Committee Vanvitelli University: 268/2016.

The Impact of Anesthetic Regimen on Outcomes in Adult Cardiac Surgery: A Narrative Review.

Despite improvements in surgical techniques and perioperative care, cardiac surgery still is burdened by relatively high mortality and frequent major postoperative complications, including myocardial dysfunction, pulmonary complications, neurologic injury, and acute kidney injury. Although the surgeon's skills and volume and patient- and procedure-related risk factors play a major role in the success of cardiac surgery, there is growing evidence that also optimizing perioperative care may improve outcomes significantly. The present review focuses on the aspects of perioperative care that are strictly related to the anesthesia regimen, with special reference to volatile anesthetics and neuraxial anesthesia, whose effect on outcome in adult cardiac surgery has been investigated extensively.

Targeting Cardiac Stem Cell Senescence to Treat Cardiac Aging and Disease.

Adult stem/progenitor are a small population of cells that reside in tissue-specific niches and possess the potential to differentiate in all cell types of the organ in which they operate. Adult stem cells are implicated with the homeostasis, regeneration, and aging of all tissues. Tissue-specific adult stem cell senescence has emerged as an attractive theory for the decline in mammalian tissue and organ function during aging. Cardiac aging, in particular, manifests as functional tissue degeneration that leads to heart failure. Adult cardiac stem/progenitor cell (CSC) senescence has been accordingly associated with physiological and pathological processes encompassing both non-age and age-related decline in cardiac tissue repair and organ dysfunction and disease. Senescence is a highly active and dynamic cell process with a first classical hallmark represented by its replicative limit, which is the establishment of a stable growth arrest over time that is mainly secondary to DNA damage and reactive oxygen species (ROS) accumulation elicited by different intrinsic stimuli (like metabolism), as well as external stimuli and age. Replicative senescence is mainly executed by telomere shortening, the activation of the p53/p16INK4/Rb molecular pathways, and chromatin remodeling. In addition, senescent cells produce and secrete a complex mixture of molecules, commonly known as the senescence-associated secretory phenotype (SASP), that regulate most of their non-cell-autonomous effects. In this review, we discuss the molecular and cellular mechanisms regulating different characteristics of the senescence phenotype and their consequences for adult CSCs in particular. Because senescent cells contribute to the outcome of a variety of cardiac diseases, including age-related and unrelated cardiac diseases like diabetic cardiomyopathy and anthracycline cardiotoxicity, therapies that target senescent cell clearance are actively being explored. Moreover, the further understanding of the reversibility of the senescence phenotype will help to develop novel rational therapeutic strategies.

Safety of low intensity oral anticoagulant therapy in patients with bileaflet mechanical aortic valve prosthesis: A propensity weighted study.

BACKGROUND: Scarce data are available on the long-term outcomes of different regimens of oral anticoagulation in an all comer population of patients undergoing aortic valve replacement with a bileaflet mechanical heart valve. METHODS: Outcomes of 88 patients discharged with a target INR of 2.0 (LOW-INR) were compared to 147 contemporary patients who have been recommended a target INR of 2.5 (CONV). Primary outcome was the composite of any thromboembolic or haemorrhagic events. Secondary outcomes were the individual components of the primary outcome, cardiovascular mortality and stroke. To reduce selection bias, a propensity weighted analysis was performed. RESULTS: After inverse probability of treatment weighting, the primary endpoint occurred in 0.7% of patient in the LOW-INR group and in 7.0% in the CONV group (p = .0255). Linearized event rate were significantly lower in the LOW-INR group (primary endpoint: rate difference - 12.0 per 1000 patient/years, p = .0052; haemorrhage: -5.8 per 1000 patient/years, p = .0330; neurological events: -7.6 per 1000 patient/years, p = .0140). Conventional target INR was associated with an increased hazard of the composite endpoint (HR 11.193, 95% CI 1.424-88.003, p = .0217). CONCLUSIONS: Lowering the intensity of oral anticoagulation resulted in a relevant clinical benefit of reduced rates of haemorrhagic and neurological adverse events in the mid-term follow-up. This report confirms the safety profile of the low INR regimen in an all comer population undergoing aortic valve replacement with an Abbott mechanical valve.

Unravelling the Biology of Adult Cardiac Stem Cell-Derived Exosomes to Foster Endogenous Cardiac Regeneration and Repair.

Cardiac remuscularization has been the stated goal of the field of regenerative cardiology since its inception. Along with the refreshment of lost and dysfunctional cardiac muscle cells, the field of cell therapy has expanded in scope encompassing also the potential of the injected cells as cardioprotective and cardio-reparative agents for cardiovascular diseases. The latter has been the result of the findings that cell therapies so far tested in clinical trials exert their beneficial effects through paracrine mechanisms acting on the endogenous myocardial reparative/regenerative potential. The endogenous regenerative potential of the adult heart is still highly debated. While it has been widely accepted that adult cardiomyocytes (CMs) are renewed throughout life either in response to wear and tear and after injury, the rate and origin of this phenomenon are yet to be clarified. The adult heart harbors resident cardiac/stem progenitor cells (CSCs/CPCs), whose discovery and characterization were initially sufficient to explain CM renewal in response to physiological and pathological stresses, when also considering that adult CMs are terminally differentiated cells. The role of CSCs in CM formation in the adult heart has been however questioned by some recent genetic fate map studies, which have been proved to have serious limitations. Nevertheless, uncontested evidence shows that clonal CSCs are effective transplantable regenerative agents either for their direct myogenic differentiation and for their paracrine effects in the allogeneic setting. In particular, the paracrine potential of CSCs has been the focus of the recent investigation, whereby CSC-derived exosomes appear to harbor relevant regenerative and reparative signals underlying the beneficial effects of CSC transplantation. This review focuses on recent advances in our knowledge about the biological role of exosomes in heart tissue homeostasis and repair with the idea to use them as tools for new therapeutic biotechnologies for "cell-less" effective cardiac regeneration approaches.