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.