SAMHD1 phosphorylation and cytoplasmic relocalization after human cytomegalovirus infection limits its antiviral activity.

SAMHD1 is a host restriction factor that functions to restrict both retroviruses and DNA viruses, based on its nuclear deoxynucleotide triphosphate (dNTP) hydrolase activity that limits availability of intracellular dNTP pools. In the present study, we demonstrate that SAMHD1 expression was increased following human cytomegalovirus (HCMV) infection, with only a modest effect on infectious virus production. SAMHD1 was rapidly phosphorylated at residue T592 after infection by cellular cyclin-dependent kinases, especially Cdk2, and by the viral kinase pUL97, resulting in a significant fraction of phosho-SAMHD1 being relocalized to the cytoplasm of infected fibroblasts, in association with viral particles and dense bodies. Thus, our findings indicate that HCMV-dependent SAMHD1 cytoplasmic delocalization and inactivation may represent a potential novel mechanism of HCMV evasion from host antiviral restriction activities.

Mechanical circulatory support in patients with cardiogenic shock not secondary to cardiotomy: a network meta-analysis.

To compare the efficacy and safety of different mechanical circulatory support (MCS) devices in CS. A total of 24 studies (7 randomized controlled trials-RCTs-and 17 non-RCTs) involving 11,117 patients were entered in a Bayesian network meta-analysis. The primary endpoint was 30-day mortality. Secondary endpoints were stroke and bleeding (requiring transfusion and/or intracranial and/or fatal). Compared with no MCS, extra-corporeal membrane oxygenation (ECMO) reduced 30-day mortality when used both alone (OR 0.37, 95% CrI 0.15-0.90) and together with the micro-axial pump Impella (OR 0.13, 95% CrI 0.02-0.80) or intra-aortic balloon pump (IABP) (OR 0.19, 95% CrI 0.05-0.63), although the relevant articles were affected by significant publication bias. Consistent results were obtained in a sensitivity analysis including only studies of CS due to myocardial infarction. After halving the weight of studies with a non-RCT design, only the benefit of ECMO + IABP on 30-day mortality was maintained (OR 0.22, 95% CI 0.057-0.76). The risk of bleeding was increased by TandemHeart (OR 13, 95% CrI 3.50-59), Impella (OR 5, 95% CrI 1.60-18), and IABP (OR 2.2, 95% CrI 1.10-4.4). No significant differences were found across MCS strategies regarding stroke. Although limited by important quality issues, the studies performed so far indicate that ECMO, especially if combined with Impella or IABP, reduces short-term mortality in CS. MCS increases the hazard of bleeding.

Atrial fibrillation and Alzheimer's disease: A conundrum.

During ageing, the prevalence of Alzheimer's disease (AD) and of cardiovascular disease CVD) increases. Our aim is to investigate the relationship between AD and CVD and its risk factors, with a view to explaining the underlying mechanisms of this association. This review is based on the material obtained via MEDLINE (PubMed), Embase and Clinical Trials databases, from January 1980 until May 2019. The search term used was "Alzheimer's disease", combined with "cardiovascular disease", "hypertension", "dyslipidaemia", "diabetes mellitus", "atrial fibrillation", "coronary artery disease", "heart valve disease", "heart failure". Out of the 1328 papers initially retrieved, 431 duplicates and 216 records in languages other than English were removed; thus, only 98 papers were included in our research material. We have found that AD and CVD are frequently associated, while both of them, alone may be considered deleterious to health, the study of their combination constitutes a clinical challenge. Further research will help to clarify the real impact of CVD and its risk factors on AD, in order to better comprehend the effects of subclinical and clinical cardiovascular diseases on the brain. It may be hypothesized that there are various mechanisms underlying the association between AD and CVD, the main ones being: hypoperfusion and emboli, atherosclerosis, furthermore in both the heart and brain of AD patients, amyloid deposits may be present, thus causing damage to these organs. We need to clarify the real impact of these underlying hypothesized mechanisms and to investigate gender issues.

Brugada syndrome and syncope: a practical approach for diagnosis and treatment.

Syncope in patients with Brugada electrocardiogram pattern may represent a conundrum in the decision algorithm because incidental benign forms, especially neurally mediated syncope, are very frequent in this syndrome similarly to the general population. Arrhythmic syncope in Brugada syndrome typically results from a self-terminating sustained ventricular tachycardia or paroxysmal ventricular fibrillation, potentially leading to sudden cardiac death. Distinguishing syncope due to malignant arrhythmias from a benign form is often difficult unless an electrocardiogram is recorded during the episode. We performed a review of the existing literature and propose a practical approach for diagnosis and treatment of the patients with Brugada syndrome and syncope.

Impact of bioprosthetic valve type on peri-procedural myocardial injury and mortality after transcatheter aortic valve replacement.

Peri-procedural myocardial injury (PPMI) is a common complication after transcatheter valve replacement (TAVR), often remaining clinically silent. The role of valve type on PPMI and the association between PPMI and mortality are still unclear. We sought to evaluate predictors and outcome of PPMI after TAVR, and the impact of self-expandable valve (SEV) vs. balloon-expandable valve (BEV) deployment on PPMI. Consecutive patients who underwent successful TAVR in a single-center from January 2014 to December 2019 were included. PPMI was defined according to a modified Valve Academic Research Consortium (VARC)-2 definition as a post-procedure elevation of troponin (with a peak value ≥ 15-times the upper-reference limit) < 72 h after TAVR. We included 596 patients, of whom 258 (43.3%) were men. Mean age was 83.4 ± 5.5 years. We deployed 368 (61.7%) BEV and 228 (38.3%) SEV. PPMI was observed in 471 (79.0%) patients. At multivariable analysis, SEV (OR 2.70, 95% CI 1.64-4.55, p < 0.001), creatinine clearance (OR 0.98, 95% CI 0.97-1.00, p = 0.011), and baseline ejection fraction (OR 1.05, 95% CI 1.02-1.07, p < 0.001) were independent predictors of PPMI; these findings were also confirmed using a propensity-weighted analysis. Thirty-day and 1-year all-cause mortality rates were 2.5% and 8.1%, respectively. No associations between PPMI and 30-day (p = 0.488) or 1-year (p = 0.139) all-cause mortality were found. Independent predictors of 30-day mortality were increasing EUROSCORE II (HR 1.16 per score point, 95% CI 1.08-1.19, p < 0.001) and life-threatening/major bleeding complications (HR 5.87, 95% CI 1.28-26.58, p = 0.019), whereas EUROSCORE II (HR 1.08, 95% CI 1.04-1.13, p = 0.031) and acute kidney injury (HR 2.59, 95% CI 1.20-5.35, p = 0.020) were related to 1-year mortality. PPMI is frequent after TAVR, but it does not affect 30-day or 1-year all-cause mortality. SEV implantation is associated with an increased frequency of PPMI.

Brugada syndrome and syncope: A systematic review.

INTRODUCTION: Distinguishing syncope due to malignant arrhythmias from an incidental benign form in Brugada syndrome (BrS) is often difficult. Through systematic literature review, we evaluated the role of syncope in predicting subsequent malignant arrhythmias in BrS. METHODS: A comprehensive literature search was performed on PubMed (MeSH search terms "Brugada syndrome" and "syncope"). Overall, 9 studies for a total of 1347 patients were included. Patients were stratified as affected by suspected arrhythmic syncope (SAS), undefined syncope (US) or neurally-mediated syncope (NMS). RESULTS: Overall, 15.7% of the 279 patients with SAS had malignant arrhythmic events during a mean follow-up of 67 months, corresponding to 2.8 events per 100/person year. At the same time, 7% of the 527 patients affected by US had malignant arrhythmias during a mean follow-up of 39 months, corresponding 2.2 events per 100/person year. Conversely, 0.7% of 541 patients with NMS had malignant arrhythmic events at follow-up, corresponding to 0.13 events per 100/person year (p = .0001 NMS versus SAS and US pooled). CONCLUSION: In BrS population, the risk of arrhythmic events in the follow-up may be stratified according to the clinical evaluation. The "relatively" low predictive value of the clinical diagnosis of SAS warrants for a more accurate multi-parametric assessment, to restrict the number of candidates for implantable cardioverter-defibrillator therapy.

A high susceptibility to redox imbalance of the transmissible stages of Plasmodium falciparum revealed with a luciferase-based mature gametocyte assay.

The goal to prevent Plasmodium falciparum transmission from humans to mosquitoes requires the identification of targetable metabolic processes in the mature (stage V) gametocytes, the sexual stages circulating in the bloodstream. This task is complicated by the apparently low metabolism of these cells, which renders them refractory to most antimalarial inhibitors and constrains the development of specific and sensitive cell-based assays. Here, we identify and functionally characterize the regulatory regions of the P. falciparum gene PF3D7_1234700, encoding a CPW-WPC protein and named here Upregulated in Late Gametocytes (ULG8), which we have leveraged to express reporter genes in mature male and female gametocytes. Using transgenic parasites containing a pfULG8-luciferase cassette, we investigated the susceptibility of stage V gametocytes to compounds specifically affecting redox metabolism. Our results reveal a high sensitivity of mature gametocytes to the glutathione reductase inhibitor and redox cycler drug methylene blue (MB). Using isobologram analysis, we find that a concomitant inhibition of the parasite enzyme glucose-6-phosphate dehydrogenase-6-phosphogluconolactonase, a key component of NADPH synthesis, potently synergizes MB activity. These data suggest that redox metabolism and detoxification activity play an unsuspected yet vital role in stage V gametocytes, rendering these cells exquisitely sensitive to decreases in NADPH concentration.

Endogenous CCL2 neutralization restricts HIV-1 replication in primary human macrophages by inhibiting viral DNA accumulation.

BACKGROUND: Macrophages are key targets of HIV-1 infection. We have previously described that the expression of CC chemokine ligand 2 (CCL2) increases during monocyte differentiation to macrophages and it is further up-modulated by HIV-1 exposure. Moreover, CCL2 acts as an autocrine factor that promotes viral replication in infected macrophages. In this study, we dissected the molecular mechanisms by which CCL2 neutralization inhibits HIV-1 replication in monocyte-derived macrophages (MDM), and the potential involvement of the innate restriction factors protein sterile alpha motif (SAM) histidine/aspartic acid (HD) domain containing 1 (SAMHD1) and apolipoprotein B mRNA-editing, enzyme-catalytic, polypeptide-like 3 (APOBEC3) family members. RESULTS: CCL2 neutralization potently reduced the number of p24 Gag+ cells during the course of either productive or single cycle infection with HIV-1. In contrast, CCL2 blocking did not modify entry of HIV-1 based Virus Like Particles, thus demonstrating that the restriction involves post-entry steps of the viral life cycle. Notably, the accumulation of viral DNA, both total, integrated and 2-LTR circles, was strongly impaired by neutralization of CCL2. Looking for correlates of HIV-1 DNA accumulation inhibition, we found that the antiviral effect of CCL2 neutralization was independent of the modulation of SAMHD1 expression or function. Conversely, a strong and selective induction of APOBEC3A expression, to levels comparable to those of freshly isolated monocytes, was associated with the inhibition of HIV-1 replication mediated by CCL2 blocking. Interestingly, the CCL2 neutralization mediated increase of APOBEC3A expression was type I IFN independent. Moreover, the transcriptome analysis of the effect of CCL2 blocking on global gene expression revealed that the neutralization of this chemokine resulted in the upmodulation of additional genes involved in the defence response to viruses. CONCLUSIONS: Neutralization of endogenous CCL2 determines a profound restriction of HIV-1 replication in primary MDM affecting post-entry steps of the viral life cycle with a mechanism independent of SAMHD1. In addition, CCL2 blocking is associated with induction of APOBEC3A expression, thus unravelling a novel mechanism which might contribute to regulate the expression of innate intracellular viral antagonists in vivo. Thus, our study may potentially lead to the development of new therapeutic strategies for enhancing innate cellular defences against HIV-1 and protecting macrophages from infection.

Multicolor bioluminescence boosts malaria research: quantitative dual-color assay and single-cell imaging in Plasmodium falciparum parasites.

New reliable and cost-effective antimalarial drug screening assays are urgently needed to identify drugs acting on different stages of the parasite Plasmodium falciparum, and particularly those responsible for human-to-mosquito transmission, that is, the P. falciparum gametocytes. Low Z' factors, narrow dynamic ranges, and/or extended assay times are commonly reported in current gametocyte assays measuring gametocyte-expressed fluorescent or luciferase reporters, endogenous ATP levels, activity of gametocyte enzymes, or redox-dependent dye fluorescence. We hereby report on a dual-luciferase gametocyte assay with immature and mature P. falciparum gametocyte stages expressing red and green-emitting luciferases from Pyrophorus plagiophthalamus under the control of the parasite sexual stage-specific pfs16 gene promoter. The assay was validated with reference antimalarial drugs and allowed to quantitatively and simultaneously measure stage-specific drug effects on parasites at different developmental stages. The optimized assay, requiring only 48 h incubation with drugs and using a cost-effective luminogenic substrate, significantly reduces assay cost and time in comparison to state-of-the-art analogous assays. The assay had a Z' factor of 0.71 ± 0.03, and it is suitable for implementation in 96- and 384-well microplate formats. Moreover, the use of a nonlysing D-luciferin substrate significantly improved the reliability of the assay and allowed one to perform, for the first time, P. falciparum bioluminescence imaging at single-cell level.

Endothelial progenitor cells in morbid obesity.

BACKGROUND: The aim of this study was to assess the relationship among anthropometric indexes of adiposity (body mass index [BMI], waist circumference [WC]), endothelial progenitor cells (EPC) and carotid intima-media thickness (IMT) in patients with morbid obesity, and the effect of diabetes and weight loss. METHODS AND RESULTS: BMI, WC, IMT and circulating EPC (defined as CD34+/KDR+/CD45- cells) were assessed in 100 patients (37 with diabetes). Fifty patients underwent bariatric surgery, and in 48 of them a complete re-assessment after an average follow-up of 252±108 days was carried out. In 29 of them subcutaneous and visceral adipose tissue samples were obtained at the time of intervention and analyzed for the presence and number of EPC. EPC were directly correlated with weight, BMI, WC and insulin level, and inversely with mean IMT. All correlations were confined to non-diabetic patients. EPC were found in both subcutaneous and visceral adipose tissue specimens. Circulating EPC significantly decreased after weight loss (P=0.002). CONCLUSIONS: EPC are positively related to markers of adiposity in severe obesity, when not complicated by diabetes. Weight loss is associated with decrease in EPC level. EPC are inversely correlated with IMT, confirming their protective role also in severe obesity. Diabetes has a negative modulating action.

Polymorphonuclear neutrophils and instability of the atherosclerotic plaque: a causative role?

OBJECTIVE: The aim of this review is to examine the role of polymorphonuclear neutrophils (PMNs) in the evolution of atherosclerosis. INTRODUCTION: While the role of PMNs in the evolution of atherosclerosic process has failed until recently to attract much attention, a body of research carried out over the last decade has disclosed the unexpectedly complex behavior of these cells, unraveling an unexpected key role for PMNs in the onset and progression of atheroma. METHODS: A PubMed database search was performed for studies providing evidences on the role of PMNs in the development and progression of atherosclerotic lesion. RESULTS AND CONCLUSIONS: Activated PMNs were shown to produce and release reactive oxygen species, inflammatory leukotrienes and proteolytic lysosomal enzymes, directly inducing vascular damage. Activated PMNs also secrete myeloperoxidase, involved in lipoprotein oxidation. PMNs have a finite lifespan and typically die through apoptosis, which thus represents a counter-regulatory mechanism limiting the toxic potential of these short-lived, terminally differentiated cells. Dysregulation of this process probably contributes to the pathogenesis and progression of several inflammatory diseases. Moreover, high circulating levels of PMN-platelet aggregates have been reported in patients with clinical atherosclerosis, and recent studies suggest that these aggregates may play a role in vascular response to injury. It has been suggested that this heterotypic interaction between platelets and leukocytes might represent a link between hemostasis/thrombosis and the inflammatory response.

A case of unusual acute coronary syndrome.

Pheochromocytoma is a rare tumor that usually develops ahead of the neuroectodermal chromaffin cells of the adrenal medulla, but it may arise anywhere within plexus of sympathetic adrenergic nerves. Headache, palpitations, tremor, excessive sweating, abdominal pain, and hypertensive paroxysm are the common clinical presentations of the tumor, but it has also been reported several cardiac symptoms.

Speckle-tracking echocardiography: state of art and its applications.

Echocardiographic evaluation of left ventricular ejection fraction (LVEF) provides important information regarding both myocardial function and prognosis. This parameter presents various limitations and does not allow early detection of myocardial dysfunction. LVEF may be related to hemodynamic load, geometric assumptions, to image quality, and it does not reflect myocardial contractility. It has been hypothesized that speckle tracking echocardiography (STE) may allow overcoming such limits. STE through the measurement of strain and strain rate, which detect myocardial deformation, allows earlier identification of myocardial dysfunction in different settings both in presence of systolic and diastolic dysfunction, helps to predict left ventricular remodeling after acute myocardial infarction (AMI), and helps to decide the timing of surgery in asymptomatic severe valvular heart disease which is still a problematic issue. Increasingly interest regards the role of STE for the assessment of cardiomyopathies, myocarditis, and pulmonary hypertension. STE may be applied to the evaluation of systolic and diastolic dysfunction. STE is useful in all conditions in which cardiac dysfunction is not still overt, but a subclinical involvement is undoubtedly present such as in presence of cardiovascular risk factors and in cardio-oncology at earlier stages. It has been confirmed its role in predicting left ventricular remodeling after AMI which represents an important prognostic datum and in deciding the timing of surgery in asymptomatic valvular diseases. STE is an important tool to detect myocardial impairment even at earlier stages. 3DSTE and layer-specific strain represent promising fields of clinical application of STE.

Long-Term Outcomes of Transvenous Lead Extraction: A Comparison in Patients with or without Infection from the Italian Region with the Oldest Population.

BACKGROUND: The gold standard for the treatment of cardiac implantable electronic devices (CIEDs)-related infection and lead malfunction is transvenous lead extraction (TLE). To date, the risk of mortality directly related to TLE procedures is relatively low, but data on post-procedural and long-term mortality are limited, even more in the aging population. METHODS: Consecutive patients with CIEDs who underwent TLE were retrospectively studied. The primary outcome was the endpoint of death, considering independent predictors of long-term clinical outcomes in the TLE aging population comparing patients with and without infection. RESULTS: One hundred nineteen patients (male 77%; median age 76 years) were included in the analysis. Eighty-two patients (69%) documented infection, and thirty-seven (31%) were extracted for a different reason. Infected patients were older (80 vs. 68 years, p-value > 0.001) with more implanted catheters (p-value < 0.001). At the last follow-up (FU) available (median FU 4.1 years), mortality reached 37% of the patient population, showing a statistically significant difference between infected versus non-infected groups. At univariable analysis, age at TLE, atrial fibrillation, and anemia remained significant correlates of mortality; at multivariable analysis, only patients with anemia and atrial fibrillation have a 2.3-fold (HR 2.34; CI 1.16-4.75) and a 2.5-fold (HR 2.46; CI 1.33-4.54) increased rate of death, respectively. CONCLUSION: Our long-term data showed that aging patients who underwent TLE for CIED-related infection exhibit a high mortality risk during a long-term follow-up, potentially leading to a rapid and effective procedural approach in this patient population.

Type 2 myocardial infarction: a diagnostic and therapeutic challenge in contemporary cardiology.

In the expanding world of cardiovascular diseases, rapidly reaching pandemic proportions, the main focus is still on coronary atherosclerosis and its clinical consequences. However, at least in the Western world, middle-aged male patients with acute myocardial infarction are no more the rule. Due to a higher life expectancy and major medical advances, physicians are to treat older and frailer individuals, usually with multiple comorbidities. In this context, myocardial ischaemia and infarction frequently result from an imbalance between myocardial oxygen supply and demand-i.e., type 2 myocardial infarction (T2MI), according to the current universal definition-rather than coronary atherothrombosis. Moreover, the increasing use of high-sensitivity cardiac troponin assays has led to a heightened detection of T2MI-often causing relatively little myocardial injury-, which seems to have doubled its numbers in recent years. Nevertheless, owing to its multifaceted pathophysiology and clinical presentation, T2MI is still underdiagnosed. Perhaps more importantly, T2MI is also victim of undertreatment, as drugs that constitute the cornerstone of therapy in most cardiovascular diseases are much more unlikely to be prescribed in T2MI than in coronary atherothrombosis. In this paper, we review the recent literature on the classification, pathophysiology, epidemiology, and management of T2MI, trying to summarise the state-of-the-art knowledge about this increasingly important pathologic condition. Finally, based on the current scientific evidence, we also propose an algorithm that may be easily utilised in clinical practice, in order to improve T2MI diagnosis and risk stratification.

Syncope in hypertrophic cardiomyopathy (part I): An updated systematic review and meta-analysis.

AIMS: To describe the proportion of patients with syncope among those affected by hypertrophic cardiomyopathy (HCM) and the relevance of syncope as risk factor for sudden cardiac death and life-threatening arrhythmic events. METHOD AND RESULTS: Systematic review of original articles that assessed syncope in HCM patients. Literature search of PubMed including all English publications from 1973 to 2021.We found 57 articles for a total of 21.791 patients; of these, 14 studies reported on arrhythmic events in the follow-up. Syncope was reported in 15.8% (3.452 of 21.791) patients. It was considered unexplained in 91% of cases. Life-threatening arrhythmic events occurred in 3.6% of non-syncopal patients and in 7.7% of syncopal patients during a mean follow-up of 5.6 years. A relative risk of 1.99 (95%CI 1.39 to 2.86) was estimated for syncope patients by the random effect model using Haldane continuity correction for 0 events. CONCLUSIONS: In the current practice, the cause of syncope remained unexplained in most patients affected by HCM. The management of patients seems mainly driven by risk stratification rather than identification of the aetiology of syncope. There is a need of precise instructions how to apply the recommendations of current guidelines to this disease, which tests are indicated and how to interpret their findings. The protocol was registered in Prospero (ID: 275963).

Duration of dual antiplatelet therapy and subsequent monotherapy type in patients undergoing drug-eluting stent implantation: a network meta-analysis.

AIMS: To compare the safety and efficacy of very short (≤3 months), short (6 months), standard (12 months), and extended (>12 months) dual antiplatelet therapy (DAPT), and of subsequent monotherapies, after coronary drug-eluting stent (DES) implantation. METHODS AND RESULTS: Twenty-two randomized control trials (n = 110 059 patients/year) were selected and included in a Bayesian network meta-analysis. The primary efficacy endpoint (PEP) was a composite of cardiac death, myocardial infarction (MI), and stent thrombosis (ST), with each of the components of the PEP being a secondary efficacy endpoint. The primary safety endpoint was major bleeding rate. Compared to standard, we found a lower rate of MI [odds ratio (OR) 0.56, 95% confidence interval (CI) 0.44-0.77] in extended, a lower rate of major bleeding (OR 0.61, 95% CI 0.39-0.87) in very short, and a lower rate of any bleeding (OR 0.61, 95% CI 0.38-0.90) in short DAPT. All DAPT durations were comparable regarding the secondary efficacy endpoints. Very short DAPT followed by P2Y12 inhibition was the treatment of choice to reduce both major bleeding and MI. In the ACS subgroup, extended DAPT (as compared to standard) reduced PEP and ST rates (but not MIs). CONCLUSION: The efficacy of short and very short is comparable with that of standard DAPT after DES implantation, whereas extended DAPT reduces MI rate. Very short DAPT is associated with lower haemorrhagic events and, followed by a P2Y12 inhibitor monotherapy, should be preferred in order to pursue a trade-off between major bleeding and ischaemic events.