Downregulation of monocytic differentiation via modulation of CD147 by 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors

Cholesterol and COVID-19-therapeutic opportunities at the host/virus interface during cell entry

The rapid development of vaccines to combat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections has been critical to reduce the severity of COVID-19. However, the continuous emergence of new SARS-CoV-2 subtypes highlights the need to develop additional approaches that oppose viral infections. Targeting host factors that support virus entry, replication, and propagation provide opportunities to lower SARS-CoV-2 infection rates and improve COVID-19 outcome. This includes cellular cholesterol, which is critical for viral spike proteins to capture the host machinery for SARS-CoV-2 cell entry. Once endocytosed, exit of SARS-CoV-2 from the late endosomal/lysosomal compartment occurs in a cholesterol-sensitive manner. In addition, effective release of new viral particles also requires cholesterol. Hence, cholesterol-lowering statins, proprotein convertase subtilisin/kexin type 9 antibodies, and ezetimibe have revealed potential to protect against COVID-19. In addition, pharmacological inhibition of cholesterol exiting late endosomes/lysosomes identified drug candidates, including antifungals, to block SARS-CoV-2 infection. This review describes the multiple roles of cholesterol at the cell surface and endolysosomes for SARS-CoV-2 entry and the potential of drugs targeting cholesterol homeostasis to reduce SARS-CoV-2 infectivity and COVID-19 disease severity.

Acute Myocardial Infarction during the COVID-19 Pandemic: Long-Term Outcomes and Prognosis-A Systematic Review

Coronavirus disease 2019 (COVID-19) was a global pandemic with high mortality and morbidity that led to an increased health burden all over the world. Although the virus mostly affects the pulmonary tract, cardiovascular implications are often observed among COVID-19 patients and are predictive of poor outcomes. Increased values of myocardial biomarkers such as troponin I or NT-proBNP were proven to be risk factors for respiratory failure. Although the risk of acute coronary syndromes (ACSs) was greater in the acute phase of COVID-19, there were lower rates of hospitalization for ACSs, due to patients' hesitation in presenting at the hospital. Hospitalized ACSs patients with COVID-19 infection had a prolonged symptom-to-first-medical-contact time, and longer door-to-balloon time. The mechanisms of myocardial injury in COVID-19 patients are still not entirely clear; however, the most frequently implicated factors include the downregulation of ACE2 receptors, endothelial dysfunction, pro-coagulant status, and increased levels of pro-inflammatory cytokines. The aim of this paper is to evaluate the long-term outcomes and prognosis of COVID-19 survivors that presented an acute myocardial infarction, by reviewing existing data. The importance of the association between this infectious disease and myocardial infarction arises from the increased mortality of patients with SARS-CoV-2 infection and AMI (10-76%, compared with 4.6% for NSTEMI patients and 7% for STEMI patients without COVID-19). The literature review showed an increased risk of cardiovascular events in COVID-19 survivors compared with the general population, even after the acute phase of the disease, with poorer long-term outcomes.

Elevated EMMPRIN Serum Levels Indicate Plaque Vulnerability in Patients With Asymptomatic High Grade Carotid Stenosis

OBJECTIVE

Carotid atherosclerosis is an important cause of cerebral ischaemic stroke. Sonographic plaque characteristics are inappropriate for exact prediction of possible future ischaemic events. Additional markers are needed to predict the clinical outcome in high grade carotid stenosis. This study aimed to test extracellular matrix metalloproteinase inducer (EMMPRIN), due to its involvement in plaque formation and destabilisation, as a potential marker of high risk vulnerable plaques.

METHODS

EMMPRIN was analysed in pre-operative serum samples from patients with symptomatic and asymptomatic carotid artery stenosis by a specific ELISA. Pre-operative duplex sonography classified the atherosclerotic plaque due to echogenicity. Histopathological analysis of vulnerable and non-vulnerable plaques was based on the American Heart Association (AHA) classification.

RESULTS

The study included 265 patients undergoing carotid endarterectomy: 90 (m:f, 69:21) patients with symptomatic and 175 (m:f, 118:57) with asymptomatic disease. Analysis of circulating EMMPRIN revealed significantly higher levels in patients with echolucent plaques (4 480; IQR 3 745, 6 144 pg/mL) compared with echogenic plaques (4 159; IQR 3 418, 5 402 pg/mL; p = .025). Asymptomatic patients with vulnerable plaques had significantly higher levels of EMMPRIN (4 875; IQR 3 850, 7 016 pg/mL) compared with non-vulnerable plaques (4 109; IQR 3 433, 5 402 pg/mL; p < .001). In logistic regression analysis, duplex sonography combined with age, gender, and clinical risk factors predicted vulnerable plaques in asymptomatic patients with an AUC of 0.71 (95% CI 0.61 - 0.80). EMMPRIN significantly improved the AUC in asymptomatic patients (AUC 0.79; 95% CI 0.71 - 0.87; p = .014).

CONCLUSION

Patients with high risk plaques according to ultrasound and histopathological characteristics demonstrated increased serum EMMPRIN levels. EMMPRIN on top of clinical risk factors, including age, gender, and duplex sonography may be used for pre-operative risk stratification in asymptomatic patients.

Capacity of HDL to Efflux Cellular Cholesterol from Lipid-Loaded Macrophages Is Reduced in Patients with Familial Hypercholesterolemia

This study aimed to evaluate the high-density lipoprotein (HDL) capacity to efflux cellular cholesterol from lipid-loaded macrophages to find a reliable and low-cost biomarker with the purpose of better evaluating the risk of premature cardiovascular (CV) events in FH patients. This case-controlled study comprised 16 homozygous (HOFH) and 18 heterozygous (HEFH) FH patients, as well as 20 healthy subjects recruited as controls. Two main subfractions of HDL (HDL2 (d = 1.063-1.125 g/mL) and HDL3 (d = 1.125-1.210 g/mL)) were isolated from the patients' serum samples using sequential ultracentrifugation. After compositional characterization, the capacity of HDL to efflux cholesterol (CEC%) from lipid-laden macrophages was measured. The HDL2 and HDL3 subfractions showed some differences in lipid and protein composition between the studied groups. In addition, both HDL subfractions (p < 0.001) revealed significantly reduced CEC% in HOFH patients (HDL2: 2.5 ± 0.1 and HDL3: 3.2 ± 0.2) in comparison with the HEFH (HDL2: 3.2 ± 0.1% and HDL3: 4.1 ± 0.2%) and healthy (HDL2: 3.3 ± 0.2% and HDL3: 4.5 ± 0.3%) subjects. Additionally, multinomial logistic regression results indicated that the CEC% of both HDL2 (OR: 0.091; 95% CI: 0.018-0.452, p < 0.01) and HDL3 (OR: 0.118; 95% CI: 0.035-0.399, p < 0.01) subfractions are strongly and inversely associated with the homozygous form of FH. A decreased capacity of HDL particles to efflux cholesterol from macrophages might identify homozygous FH patients who are at elevated risk for premature CVDs. Prospective studies with a large sample size are warranted to evaluate this hypothesis.

Systematic Review and Meta-Analysis of Statin Use and Mortality, Intensive Care Unit Admission and Requirement for Mechanical Ventilation in COVID-19 Patients

There is mounting evidence that statin use is beneficial for COVID-19 outcomes. We performed a systematic review and meta-analysis to evaluate the association between statin use and mortality, intensive care unit (ICU) admission and mechanical ventilation in COVID-19 patients, on studies which provided covariate adjusted effect estimates, or performed propensity score matching. We searched PubMed, Embase, Web of Science and Scopus for studies and extracted odds or hazard ratios for specified outcome measures. Data synthesis was performed using a random-effects inverse variance method. Risk of bias, heterogeneity and publication bias were analyzed using standard methods. Our results show that statin use was associated with significant reductions in mortality (OR = 0.72, 95% CI: 0.67–0.77; HR = 0.74, 95% CI: 0.69, 0.79), ICU admission (OR = 0.94, 95% CI: 0.89–0.99; HR = 0.76, 95% CI: 0.60–0.96) and mechanical ventilation (OR = 0.84, 95% CI: 0.78–0.92; HR = 0.67, 95% CI: 0.47–0.97). Nevertheless, current retrospective studies are based on the antecedent use of statins prior to infection and/or continued use of statin after hospital admission. The results may not apply to the de novo commencement of statin treatment after developing COVID-19 infection. Prospective studies are lacking and necessary.

Human Cell Organelles in SARS-CoV-2 Infection: An Up-to-Date Overview

Since the end of 2019, the whole world has been struggling with the life-threatening pandemic amongst all age groups and geographic areas caused by Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2). The Coronavirus Disease 2019 (COVID-19) pandemic, which has led to more than 468 million cases and over 6 million deaths reported worldwide (as of 20 March 2022), is one of the greatest threats to human health in history. Meanwhile, the lack of specific and irresistible treatment modalities provoked concentrated efforts in scientists around the world. Various mechanisms of cell entry and cellular dysfunction were initially proclaimed. Especially, mitochondria and cell membrane are crucial for the course of infection. The SARS-CoV-2 invasion depends on angiotensin converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2), and cluster of differentiation 147 (CD147), expressed on host cells. Moreover, in this narrative review, we aim to discuss other cell organelles targeted by SARS-CoV-2. Lastly, we briefly summarize the studies on various drugs.

SARS-CoV-2 spike protein causes cardiovascular disease independent of viral infection

The SARS-CoV-2 virus that results in COVID-19 has been found to damage multiple organs beyond the lung. Interestingly, the SARS-CoV-2 spike (S) protein can be found circulating in the blood of COVID-19 patients. Experimental findings are demonstrating that the circulating S protein can bind to receptors resulting in inflammation and cell, tissue, and organ damage. Avolio et al. previously determined that the S protein acting through the cluster of differentiation 147 (CD147) receptor, and another unknown mechanism had detrimental effects on human cardiac pericytes (Clin Sci (Lond) (2021) 135 (24): 2667–2689. DOI: 10.1042/CS20210735). These findings support the notion that circulating SARS-CoV-2 S protein could contribute to cardiovascular disease independent of viral infection. Future studies are needed to determine the effect of the S protein on pericytes in other organs and evaluate the effectiveness of CD147 receptor-blocking therapies to decrease organ damage caused by the S protein.

CD147-spike protein interaction in COVID-19: Get the ball rolling with a novel receptor and therapeutic target

The combat against the Corona virus disease of 2019 (COVID-19), has created a chaos among the healthcare institutions and researchers, in turn accelerating the dire need to curtail the infection spread. The already established entry mechanism, via ACE2 has not yet successfully aided in the development of a suitable and reliable therapy. Taking in account the constant progression and deterioration of the cases worldwide, a different perspective and mechanistic approach is required, which has thrown light onto the cluster of differentiation 147 (CD147) transmembrane protein, as a novel route for SARS-CoV-2 entry. Despite lesser affinity towards COVID-19 virus, as compared to ACE2, this receptor provides a suitable justification behind elevated blood glucose levels in infected patients, retarded COVID-19 risk in women, enhanced susceptibility in geriatrics, greater infection susceptibility of T cells, infection prevalence in non-susceptible human cardiac pericytes and so on. The manuscript invokes the title role and distribution of CD147 in COVID-19 as an entry receptor and mediator of endocytosis-promoted entry of the virus, along with the "catch and clump" hypothesis, thereby presenting its Fundamental significance as a therapeutic target for potential candidates, such as Azithromycin, melatonin, statins, beta adrenergic blockers, ivermectin, Meplazumab etc. Thus, the authors provide a comprehensive review of a different perspective in COVID-19 infection, aiming to aid the researchers and virologists in considering all aspects of viral entry, in order to develop a sustainable and potential cure for the 2019 COVID-19 disease.

Could Statin Therapy Be Useful in Patients With Coronavirus Disease 2019 (COVID-19)?

Acute respiratory distress syndrome (ARDS), resulting from an exaggerated inflammatory response, is the main cause of death from the coronavirus disease 2019 (COVID-19). Apart from respiratory infection, COVID-19 patients can develop cardiovascular disorders such as myocardial injury and myocarditis, pericarditis, cardiac arrest and arrhythmias, cardiomyopathy, heart failure, coagulation abnormalities and thrombosis. Statins can beneficially affect inflammation, oxidative stress, coagulation, thrombosis, angiotensin converting enzyme receptor, lipid rafts, and endothelial function. In this narrative review, we provide a critical overview of the current evidence and future perspectives on the use of statins to modulate the severity, duration and complications of COVID-19 through their pleiotropic properties.

Palmitic acid up regulates Gal-3 and induces insulin resistance in macrophages by mediating the balance between KLF4 and NF-κB

Insulin resistance is the main sign of type 2 diabetes mellitus and is often accompanied by the infiltration of inflammatory factors. These inflammatory factors are mainly produced and secreted by macrophages. The purpose of the current study was to explore the relationship between macrophages and insulin resistance, and to determine its underlying mechanism. The insulin resistance of macrophages was induced by palmitic acid (PA) in vitro. The glucose uptake rate of macrophages, the expression levels of inflammatory cytokines and the expression levels of insulin resistance-related proteins were detected. The protein expression levels of Krüppel-like factor 4 (KLF4), toll-like receptor 4 (TLR4), NF-κB and Galectin-3 (Gal-3) were detected via western blotting and recovery experiments were performed by combining the Gal-3 and TLR4 inhibitors GB1107 and TAK242. The results revealed that PA-induced macrophages demonstrated insulin resistance. Additionally, KLF4 protein was inhibited and the sugar uptake rate was significantly lower than that of the control group. Western blotting and immunofluorescence assays revealed that the expression of Gal-3 in PA-induced macrophages was significantly upregulated. The addition of the Gal-3 inhibitor GB1107 significantly increased glucose utilization and reduced insulin resistance in PA-treated cells. Inhibitor of TLR4 inhibited the protein expression level of the TLR4/NF-κB pathway. In conclusion, PA promoted the TLR4/phosphorylated-NF-κB signaling pathway by inhibiting KLF4, promoted the upregulation of Gal-3 expression and improved the insulin resistance of macrophages.

A comprehensive guide to the pharmacologic regulation of angiotensin converting enzyme 2 (ACE2), the SARS-CoV-2 entry receptor

The recent emergence of coronavirus disease-2019 (COVID-19) as a global pandemic has prompted scientists to address an urgent need for defining mechanisms of disease pathology and treatment. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent for COVID-19, employs angiotensin converting enzyme 2 (ACE2) as its primary target for cell surface attachment and likely entry into the host cell. Thus, understanding factors that may regulate the expression and function of ACE2 in the healthy and diseased body is critical for clinical intervention. Over 66% of all adults in the United States are currently using a prescription drug and while earlier findings have focused on possible upregulation of ACE2 expression through the use of renin angiotensin system (RAS) inhibitors, mounting evidence suggests that various other widely administered drugs used in the treatment of hypertension, heart failure, diabetes mellitus, hyperlipidemias, coagulation disorders, and pulmonary disease may also present a varied risk for COVID-19. Specifically, we summarize mechanisms on how heparin, statins, steroids and phytochemicals, besides their established therapeutic effects, may also interfere with SARS-CoV-2 viral entry into cells. We also describe evidence on the effect of several vitamins, phytochemicals, and naturally occurring compounds on ACE2 expression and activity in various tissues and disease models. This comprehensive review aims to provide a timely compendium on the potential impact of commonly prescribed drugs and pharmacologically active compounds on COVID-19 pathology and risk through regulation of ACE2 and RAS signaling.

COVID-19 and Pregnancy: Vertical Transmission and Inflammation Impact on Newborns

The COVID-19 pandemic is ongoing and we are still compiling new findings to decipher and understand SARS-CoV-2 infection during pregnancy. No reports encompass any conclusive confirmation of vertical transmission. Nevertheless, cases of fetal distress and multiple organ failure have been reported, as well as rare cases of fetal demise. While clinicians and scientists continue to seek proof of vertical transmission, they miss the greater point, namely the cause of preterm delivery. In this review, we suggest that the cause might not be due to the viral infection but the fetal exposure to maternal inflammation or cytokine storm that translates into a complication of COVID-19. This statement is extrapolated from previous experience with infections and inflammation which were reported to be fatal by increasing the risk of preterm delivery and causing abnormal neonatal brain development and resulting in neurological disorders like atypical behavioral phenotype or autistic syndrome. Given the potentially fatal consequences on neonate health, we highlight the urgent need for an animal model to study vertical transmission. The preclinical model will allow us to make the link between SARS-COV-2 infection, inflammation and long-term follow-up of child brain development.

A sweet spot for macrophages: Focusing on polarization

Macrophages are a type of functionally plastic cells that can create a pro-/anti-inflammatory microenvironment for organs by producing different kinds of cytokines, chemokines, and growth factors to regulate immunity and inflammatory responses. In addition, they can also be induced to adopt different phenotypes in response to extracellular and intracellular signals, a process defined as M1/M2 polarization. Growing evidence indicates that glycobiology is closely associated with this polarization process. In this research, we review studies of the roles of glycosylation, glucose metabolism, and key lectins in the regulation of macrophages function and polarization to provide a new perspective for immunotherapies for multiple diseases.

Statins as an adjunctive therapy for COVID-19: the biological and clinical plausibility

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes the coronavirus disease 2019 (COVID-19) has infected millions of individuals and has claimed hundreds of thousands of human lives worldwide. Patients with underlying cardiovascular conditions are at high risk for SARS-CoV-2 infection, and COVID-19 patients have high incidence of cardiovascular complications such as acute cardiac injury, arrhythmias, heart failure, and thromboembolism. The disease has no approved proven effective therapy and hence repurposing of existing approved drugs has been considered as the fastest treatment approach. Statins have been shown to exhibit lipid lowering dependent and independent cardiovascular protective effects as well as favorable effects in various other pathophysiological states. These beneficial properties of statins are a result of their multiple pleotropic effects that include, anti-inflammatory, immunomodulatory, antithrombotic and antimicrobial properties. In this review, we provide a comprehensive description of the mechanisms of the pleotropic effects of statins, the relevant pre-clinical and clinical data pertinent to their role in infections and acute lung injury, the possible cardiovascular benefits of statins in COVID-19, and the implications of the therapeutic potential of statins in COVID-19 disease. We conclude with the rationale for conducting randomized controlled trials of statins in COVID-19 disease.

Dysregulation of the mevalonate pathway during SARS-CoV-2 infection: An in silico study

SARS-CoV-2 triggers a dysregulated innate immune system activation. As the mevalonate pathway (MVP) prevents the activation of inflammasomes and cytokine release and regulates endosomal transport, compromised signaling could be associated with the pathobiology of COVID-19. Prior transcriptomic studies of host cells in response to SARS-CoV-2 infection have not reported to date the effects of SARS-CoV-2 on the MVP. In this study, we accessed public data sets to report in silico investigations into gene expression. In addition, we proposed candidate genes that are thought to have a direct association with the pathogenesis of COVID-19, and which may be dependent on signals derived from the MVP. Our results revealed dysregulation of genes involved in the MVP. These results were not found when investigating the gene expression data from host cells infected with H3N2 influenza virus, H1N1 influenza virus, or respiratory syncytial virus. Our manually curated gene set showed significant gene expression variability in A549 cells infected with SARS-CoV-2, as per Blanco-Melo et al. data set (GSE147507). In light of the present findings, SARS-CoV-2 could hijack the MVP, leading to hyperinflammatory responses. Prompt reconstitution of this pathway with available agents should be considered in future studies.

Inhibitors of 3-Hydroxy-3-Methylglutaryl Coenzyme a Reductase (Statins) Suppress Differentiation and Reduce LPS/IFNγ-Induced Cytokine Production in Human Monocyte/Macrophage Culture

We examined the effects of 72-h exposure to atorvastatin and rosuvastatin in concentrations of 2-10 nM on the cytokine expression in LPS/IFNγ-activated monocyte/macrophages derived from peripheral blood monocytes of healthy donors by culturing in the presence of GM-CSF. Pretreatment with statins was found to inhibit cytokine production in monocytes/macrophages after activation, while the level of cytokine mRNA in cells did not decrease. The number of cells containing active caspase-3 decreased in the culture. Culturing of monocytes/macrophages with statins was accompanied by changes in cell morphology and deceleration of cell growth. Cellular effects of "lipophilic" atorvastastin were observed at lower concentration compared to "hydrophilic" rosuvastatin.

Statins: Could an old friend help in the fight against COVID-19?

The COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has overwhelmed healthcare systems requiring the rapid development of treatments, at least, to reduce COVID-19 severity. Drug repurposing offers a fast track. Here, we discuss the potential beneficial effects of statins in COVID-19 patients based on evidence that they may target virus receptors, replication, degradation, and downstream responses in infected cells, addressing both basic research and epidemiological information. Briefly, statins could modulate virus entry, acting on the SARS-CoV-2 receptors, ACE2 and CD147, and/or lipid rafts engagement. Statins, by inducing autophagy activation, could regulate virus replication or degradation, exerting protective effects. The well-known anti-inflammatory properties of statins, by blocking several molecular mechanisms, including NF-κB and NLRP3 inflammasomes, could limit the "cytokine storm" in severe COVID-19 patients which is linked to fatal outcome. Finally, statin moderation of coagulation response activation may also contribute to improving COVID-19 outcomes. LINKED ARTICLES: This article is part of a themed issue on The Pharmacology of COVID-19. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.21/issuetoc.

Obesity, Diabetes and COVID-19: An Infectious Disease Spreading From the East Collides With the Consequences of an Unhealthy Western Lifestyle

The pandemic of COVID-19, caused by the coronavirus, SARS-CoV-2, has had a global impact not seen for an infectious disease for over a century. This acute pandemic has spread from the East and has been overlaid onto a slow pandemic of metabolic diseases of obesity and diabetes consequent from the increasing adoption of a Western-lifestyle characterized by excess calorie consumption with limited physical activity. It has become clear that these conditions predispose individuals to a more severe COVID-19 with increased morbidity and mortality. There are many features of diabetes and obesity that may accentuate the clinical response to SARS-CoV-2 infection: including an impaired immune response, an atherothrombotic state, accumulation of advanced glycation end products and a chronic inflammatory state. These could prime an exaggerated cytokine response to viral infection, predisposing to the cytokine storm that triggers progression to septic shock, acute respiratory distress syndrome, and multi-organ failure. Infection leads to an inflammatory response and tissue damage resulting in increased metabolic activity and an associated increase in the mechanisms by which cells ingest and degrade tissue debris and foreign materials. It is becoming clear that viruses have acquired an ability to exploit these mechanisms to invade cells and facilitate their own life-cycle. In obesity and diabetes these mechanisms are chronically activated due to the deteriorating metabolic state and this may provide an increased opportunity for a more profound and sustained viral infection.

Assessment of Cytocompatibility and Anti-Inflammatory (Inter)Actions of Genipin-Crosslinked Chitosan Powders

Chitosan is a polysaccharide commonly used, together with its derivatives, in the preparation of hydrogel formulations, scaffolds and films for tissue engineering applications. Chitosan can be used as such, but it is commonly stabilized by means of chemical crosslinkers. Genipin is one of the crosslinkers that has been considered that is a crystalline powder extracted from the fruit of Gardenia jasminoides and processed to obtain an aglycon compound. Genipin is gaining interest in biological applications because of its natural origin and anti-inflammatory actions. In this paper, the ability of chitosan-based materials crosslinked with genipin to exert anti-inflammation properties in applications such as bone regeneration was studied. Powders obtained from chitosan–genipin scaffolds have been tested in order to mimic the natural degradation processes occurring during biomaterials implantation in vivo. The results from osteoblast-like cells showed that specific combinations of chitosan and genipin stimulate high permissiveness towards cells, with higher performance than the pure chitosan. In parallel, evidences from monocyte-like cells showed that the crosslinker, genipin, seems to promote slowing of the monocyte-macrophage transition at morphological level. This suggests a sort of modularity of pro-inflammatory versus anti-inflammatory behavior of our chitosan-based biomaterials. Being both the cell types exposed to microscale powders, as an added value our results bring information on the cell–material interactions in the degradative dynamics of chitosan scaffold structures during the physiological resorption processes.

ACE2 as a Therapeutic Target for COVID-19; its Role in Infectious Processes and Regulation by Modulators of the RAAS System

Angiotensin converting enzyme 2 (ACE2) is the recognized host cell receptor responsiblefor mediating infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). ACE2bound to tissue facilitates infectivity of SARS-CoV-2; thus, one could argue that decreasing ACE2tissue expression would be beneficial. However, ACE2 catalytic activity towards angiotensin I (AngI) and II (Ang II) mitigates deleterious effects associated with activation of the renin-angiotensinaldosteronesystem (RAAS) on several organs, including a pro-inflammatory status. At the tissuelevel, SARS-CoV-2 (a) binds to ACE2, leading to its internalization, and (b) favors ACE2 cleavage toform soluble ACE2: these actions result in decreased ACE2 tissue levels. Preserving tissue ACE2activity while preventing ACE2 shredding is expected to circumvent unrestrained inflammatoryresponse. Concerns have been raised around RAAS modulators and their effects on ACE2expression or catalytic activity. Various cellular and animal models report conflicting results invarious tissues. However, recent data from observational and meta-analysis studies in SARS-CoV-2-infected patients have concluded that RAAS modulators do not increase plasma ACE2 levels orsusceptibility to infection and are not associated with more severe diseases. This review presentsour current but evolving knowledge of the complex interplay between SARS-CoV-2 infection, ACE2levels, modulators of RAAS activity and the effects of RAAS modulators on ACE2 expression.

Metalloproteinases at the surface of small extrcellular vesicles in advanced ovarian cancer: Relationships with ascites volume and peritoneal canceromatosis index

Metalloproteinases and their extracellular matrix metalloproteinase inducer (EMMPRIN) play an essential role in the regulation of signaling from growth factors receptors and adhesion molecules, cell motility and extracellular matrix degradation. The aim of the study was to evaluate the relationship between the levels of small extracellular vesicles (sEVs) metalloproteinases, such as ADAM10, ADAM17, MMP2, MMP9 and EMMPRIN and ascites volume and peritoneal canceromatosis index in advanced ovarian cancer patients (OCPs). The subpopulations of metalloproteinases at the surface of sEVs of borderline ovarian tumor patients (BOTPs) (n = 20, 36.5 ± 2.5 years) and previously untreated advanced OCPs (n = 35, 56.5 ± 2.5 years) were evaluated using flow cytometry. The metalloproteinase subpopulations of CD9-positive sEVs isolated from plasma of BOTPs and OCPs appeared to be quite similar. However, a significant difference in the expression of ADAM-metalloproteinases in ascites sEVs was found between BOTPs and OCPs. The level of sEVs metalloproteinases in OCPs significantly depended on the ascites volume. A statistically significant relationship between the level of ADAM10+/ADAM17- subpopulation in plasma sEVs and the peritoneal canceromatosis index was found (R = 0.66, p < .05). The levels of metalloproteinases and EMMPRIN in circulating sEVs, as well as the assessment of individual subpopulations may be promising approaches to OCPs managing.

Hyperlipidemia, statin use and dengue severity

Multiple in vitro and mice model studies suggest statins may attenuate dengue severity. However, little is known about statin use and dengue severity in adult dengue patients with hyperlipidemia. We conducted a retrospective cohort study from 2004–2008 and 2012–2013 in Tan Tock Seng Hospital, Singapore on adult dengue patients with hyperlipidemia, comparing those with and without statin usage at hospitalization in terms of primary outcome of dengue hemorrhagic fever (DHF) or shock syndrome (DSS), and severe dengue (SD). Of 13,975 subjects screened, 257 dengue patients were included; 191 (74.3%) were statin users and 66 (25.7%) were non-users. Compared with non-users, statin use was not associated with decreased risk of DHF/DSS (adjusted risk ratio [aRR] = 0.66, 95%confidence interval [CI]: 0.41–1.08, P = 0.10) and SD (aRR = 1.43, 95%CI: 0.84–2.43, P = 0.19). Therefore, statin usage had minimal effect on dengue severity in our study population in Singapore.