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Scavenger receptors (SR) are not only pattern recognition receptors involved in the immune response against pathogens but are also important receptors exploited by different virus to enter host cells, and thus represent targets for antiviral therapy. The high mutation rates of viruses, as well as their small genomes are partly responsible for the high rates of virus resistance and effective treatments remain a challenge. Most currently approved formulations target viral-encoded factors. Nevertheless, host proteins may function as additional targets. Thus, there is a need to explore and develop new strategies aiming at cellular factors involved in virus replication and host cell entry. SR-virus interactions have implications in the pathogenesis of several viral diseases and in adenovirus-based vaccination and gene transfer technologies, and may function as markers of severe progression. Inhibition of SR could reduce adenoviral uptake and improve gene therapy and vaccination, as well as reduce pathogenesis. In this review, we will examine the crucial role of SR play in cell entry of different types of human virus, which will allow us to further understand their role in protection and pathogenesis and its potential as antiviral molecules. The recent discovery of SR-B1 as co-factor of SARS-Cov-2 (severe acute respiratory syndrome coronavirus 2) entry is also discussed. Further fundamental research is essential to understand molecular interactions in the dynamic virus-host cell interplay through SR for rational design of therapeutic strategies.

Background Covid-19 in Mexico is on the rise in different parts of the country. We aimed to study the symptoms and comorbidities that associate with this pandemic in 3 different regions of Mexico. Methods We analyzed data from SARS-CoV-2 positive patients evaluated at healthcare centers and hospitals of Mexico (n = 1607) including Northwest Mexico (Sinaloa state), Southeast Mexico (Veracruz state) and West Mexico (Jalisco state) between March 1 and July 30, 2020. Mexico consists of a total population that exceeds 128 million. Demographics, comorbidities and clinical symptoms were collected. Statistical descriptive analysis and correlation analyses of symptoms, comorbidities and mortality were performed. Results A total of 1607 hospitalized patients positive for COVID-19 across all 3 regions of Mexico were included. The average age was 54.6 years and 60.4% were male. A mortality rate of 33.1% was observed. The most common comorbidities were hypertension (43.2%), obesity (30.3%) and diabetes (31.4%). Hypertension was more frequent in West (45%), followed by Northwest (37%) and Southeast Mexico (29%). Obesity was around 30% in Northwest and West whereas an 18% was reported in Southeast. Diabetes was most common in West (34%) followed by Northwest (22%) and Southeast (13%). This might be related to the highest mortality rate in Northwest (31%) and West (37%) when compared to Southeast. Most common symptoms in our overall cohort were fever (80.8%), cough (79.8%), headache (66%), dyspnea (71.1%), myalgia (53.8%), joints pain (50.8%) and odynophagia (34.8%). Diarrhea was the main gastrointestinal (GI) symptom (21.3%), followed by abdominal pain (18%), and nausea/ vomiting (4.5%). Diarrhea and abdominal pain were more common in West (23.1 and 21%), followed by Southeast (17.8, and 9.8%) and Northwest (11.4 and 3.1%). Conclusion Our study showed a high mortality rate likely related to high frequencies of comorbidities (hypertension, obesity and diabetes). Mortality was different across regions. These discrepancies might be related to the differences in the frequencies of comorbidities, and partially attributed to differences in socio-economic conditions and quality of care. Thus, our findings stress the need for improved strategies to get better outcomes in our population.

Background: Latin America has become the epicenter of the coronavirus disease 2019 (COVID-19) pandemic. We aim to perform a systematic comparative review of the clinical characteristics that are associated with this disease in Latin American countries. Methods: We conducted a systematic review of published articles, journal and/or epidemiological reports of confirmed COVID-19 cases in Latin America. Data were obtained either through publicly available information from Ministries of Health, published journal reports and/or unpublished datasets. We analyzed data from SARS-CoV-2 positive patients evaluated at healthcare centers and hospitals of 8 countries including Brazil, Peru, Mexico, Argentina, Colombia, Venezuela, Ecuador, and Bolivia, between March 1st and July 30th, 2020. These countries consist of a total population that exceeds 519 million. Demographics, comorbidities, and clinical symptoms were collected. Statistical descriptive analysis and correlation analyses of symptoms, comorbidities and mortality were performed. Results: A total of 728,282 COVID-19 patients were included in this study. Of these, 52.6% were female. The average age was 48.4 years. Peru had the oldest cohort with 56.8 years and highest rate of females (56.8%) while Chile had the youngest cohort (39 years old). Venezuela had the highest male prevalence (56.7%). Most common symptoms were cough with 60.1% (Bolivia had the highest rate 78%), fatigue/tiredness with 52.0%, sore throat with 50.3%, and fever with 44.2%. Bolivian patients had fever as the top symptom (83.3%). GI symptoms included diarrhea which was highest in Mexico with 22.9%. Hypertension was among the top (12.1%) comorbidities, followed by diabetes with 8.3% and obesity at 4.5%. In multivariate analyses, the leading and significant comorbidities were hypertension (r = 0.83, p = 0.02), diabetes (r = 0.91, p = 0.01), and obesity (r = 0.86, p = 0.03). Mortality was highest in Mexico (16.6%) and lowest in Venezuela (0.9%) among the analyzed cohorts. Conclusion: Overall, COVID-19 patients in Latin America display cough, fatigue, and fever as main symptoms. Up to 53% of patients with COVID-19 have GI manifestations. Different clinical symptoms were associated with COVID-19 in Latin American countries. Metabolic syndrome components were the main comorbidities associated with poor outcome. Country-specific management and prevention plans are needed and can be established from this meta-analysis. Keywords: Coronavirus Disease-19; Pandemic; Gastrointestinal Manifestation; Diarrhea Abbreviations: ACE2: Angiotensin Receptor 2; CI: Confidence Interval; COVID-19: Coronavirus Disease-19; GI: Gastrointestinal; RT-PCR: Real-time Polymerase Chain Reaction; SARS-CoV-2: Severe Acute Respiratory Syndrome Coronavirus-2; TMPRSS: Transmembrane Serine Protease

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We aimed to characterize the contribution of hepatitis E virus (HEV) in perpetuating the cytokine-mediated inflammatory setting related to liver damage in the context of obesity. Herein, serum samples from patients with liver disease were retrospectively analyzed and categorized as normal-weight patients (NW), overweight patients (OW), obese patients (ObP), and high alcohol consumer patients (HAC), and biochemical, anthropometrical, and transient elastography measurements were obtained. The positivity for immunoglobulin M (IgM) and immunoglobulin G (IgG) anti-HEV antibodies in samples was determined by enzyme-linked immunosorbent assay. Available samples from ObP were tested by reverse transcription-nested polymerase chain reaction for the presence of HEV-RNA. Cytokine profile in the serum of ObP was identified using a multiplexed immune assay. Globally, the highest frequency of IgG anti-HEV was found in ObP (57.5%), followed by HAC (20%), OW (15%), and NW (7.5%). A strong association between HEV serology and obesity was found (odds ratio = 4.21, confidence interval = 1.91.9.27) with a cutoff of 29.3 kg/m

Background By end December of 2021, COVID-19 has infected around 276 million individuals and caused over 5 million deaths worldwide. Infection results in dysregulated systemic inflammation, multi-organ dysfunction, and critical illness. Cells of the central nervous system are also affected, triggering an uncontrolled neuroinflammatory response. Low doses of glucocorticoids, administered orally or intravenously, reduce mortality among moderate and severe COVID-19 patients. However, low doses administered by these routes do not reach therapeutic levels in the CNS. In contrast, intranasally administered dexamethasone can result in therapeutic doses in the CNS even at low doses. Methods This is an approved open-label, multicenter, randomized controlled trial to compare the effectiveness of intranasal versus intravenous dexamethasone administered in low doses to moderate and severe COVID-19 adult patients. The protocol is conducted in five health institutions in Mexico City. A total of 120 patients will be randomized into two groups (intravenous vs. intranasal) at a 1:1 ratio. Both groups will be treated with the corresponding dexamethasone scheme for 10 days. The primary outcome of the study will be clinical improvement, defined as a statistically significant reduction in the NEWS-2 score of patients with intranasal versus intravenous dexamethasone administration. The secondary outcome will be the reduction in mortality during hospitalization. Conclusions This protocol is currently in progress to improve the efficacy of the standard therapeutic dexamethasone regimen for moderate and severe COVID-19 patients. Trial registration ClinicalTrials.govNCT04513184. Registered November 12, 2020. Approved by La Comisión Federal para la Protección contra Riesgos Sanitarios (COFEPRIS) with identification number DI/20/407/04/36. People are currently being recruited. Graphical abstract

COVID-19 presents primarily as a lower respiratory tract infection, but the multisystemic nature of the disease, mainly associated with the broad cellular distribution of the angiotensin-converting enzyme 2 (ACE2) viral receptor, has been described. Indeed, multiple symptoms associated with COVID-19 have been identified, and underlying comorbidities have been related to poor outcomes. However, studies related to the clinical progression of the disease have mainly been conducted in the first regions affected by the pandemic. Thus, differences associated with specific populations have yet to be addressed to obtain a complete perspective of the disease. The Latin American region (LA), characterized by vast inequalities and a high prevalence of metabolic diseases, is expected to be one of the most affected regions during the pandemic. In this chapter, the clinical progression of patients with COVID-19 is reviewed and special emphasis on the clinical characteristics associated with COVID-19 in LA is presented.

Introduction and Objectives To characterize the virological features of hepatitis E virus (HEV) in serum from patients exhibiting chronic liver damage. Methods A data-base of 513 unrelated individuals from West-Mexico with liver-disease determined by clinical and biochemical tests and transient elastography between 2011 and 2016 were retrospectively analyzed. According to infectious etiologies, patients were classified as hepatitis B virus (HBV)-, hepatitis C virus (HCV)-infected patients, and patients exhibiting chronic liver damage with non-identified infectious etiological agent (NIIEA). Available serum samples from NIIEA-patients were tested by RT-nPCR for the presence of HEV-RNA and partially sequenced for genotyping. Results Out of the 513 cases, 5.85% were patients infected with HBV, 67.64% with HCV, and 26.51% were NIIEA-patients. Among 76 available samples from NIIEA-cases, 30.26% tested positive for HEV-RNA. Twelve (15.79%) partial HEV sequences allowed phylogenetic analysis, revealing the classification of HEV as HEV-Gt3. Advanced fibrosis (F3–F4 stage) was found in a 26.1% of patients with HEV-active infection. Conclusion Although HCV is the main infectious agent related to chronic liver disease in Mexico, liver damage without an infectious etiology is common. Our findings reveal that an elevated rate of chronic liver disease might be represented by autochthonous infection of HEV-Gt3, whose detection makes Mexico unique in Latin-America with the circulation of HEV strains belonging to three genotypes (Gt1, Gt2, and Gt3). Thus, HEV infection should be a matter of health concern, and mandates for HEV screening to properly handle this commonly undiagnosed disease.

CD4 + T cell differentiation is governed by gene regulatory and metabolic networks, with both networks being highly interconnected and able to adapt to external stimuli. Th17 and Tregs differentiation networks play a critical role in cancer, and their balance is affected by the tumor microenvironment (TME). Factors from the TME mediate recruitment and expansion of Th17 cells, but these cells can act with pro or anti-tumor immunity. Tregs cells are also involved in tumor development and progression by inhibiting antitumor immunity and promoting immunoevasion. Due to the complexity of the underlying molecular pathways, the modeling of biological systems has emerged as a promising solution for better understanding both CD4 + T cell differentiation and cancer cell behavior. In this review, we present a context-dependent vision of CD4 + T cell transcriptomic and metabolic network adaptability. We then discuss CD4 + T cell knowledge-based models to extract the regulatory elements of Th17 and Tregs differentiation in multiple CD4 + T cell levels. We highlight the importance of complementing these models with data from omics technologies such as transcriptomics and metabolomics, in order to better delineate existing Th17 and Tregs bifurcation mechanisms. We were able to recompilate promising regulatory components and mechanisms of Th17 and Tregs differentiation under normal conditions, which we then connected with biological evidence in the context of the TME to better understand CD4 + T cell behavior in cancer. From the integration of mechanistic models with omics data, the transcriptomic and metabolomic reprograming of Th17 and Tregs cells can be predicted in new models with potential clinical applications, with special relevance to cancer immunotherapy.

Background: Latin America has now become the epicenter of the global coronavirus disease 2019 (COVID-19) pandemic. In the ongoing COVID -19 pandemic, a profound burden of SARS-COV-2 infection has been reported in Latin America. In the present study, we aim to determine the profiles that are associated with this disease in Latin America. We analyzed symptoms, morbidities and gastrointestinal (GI) manifestations by country.Methods: We analyzed data from SARS-CoV-2 positive patients evaluated at healthcare centers and hospitals of 8 Latin American countries including Brazil, Peru, Mexico, Argentina, Colombia, Venezuela, Ecuador, and Bolivia between March 1 and July 30, 2020. These countries consist of a total population that exceeds 519 million. Demographics, comorbidities and clinical symptoms were collected. Statistical descriptive analysis and correlation analyses of symptoms, comorbidities and lethality were performed.Results: A total of 728,282 patients tested positive for COVID-19 across all the 8 Latin American countries. Of these, 52.6% were female. The average age was 48.4 years. Peru had the oldest cohort with 56.8 years old and highest rate of females (56.8%) while Chile had the youngest cohort (39 years old). Venezuela had the highest male prevalence (56.7%). Most common symptoms were cough with 60.1% (Bolivia had the highest rate 78%), fatigue/tiredness with 52.0%, sore throat with 50.3%, and fever with 44.2%. Bolivia had fever as the top symptom (83.3%). GI symptoms including diarrhea (highest in Mexico with 22.9%), nausea, vomiting, and abdominal pain were not associated with higher mortality. Hypertension was among the top (12.1%) comorbidities followed by diabetes with 8.3% and obesity 4.5%. In multivariable analyses, the leading and significant comorbidities were hypertension (r=0.83, p=0.02), diabetes (r=0.91, p=0.01), and obesity (r=0.86, p=0.03). Asthma (r=0.37, p=0.54) and increasing age (0.13 p=0.81) were not independently associated with higher mortality. Lethality was highest in Mexico (16.6%) and lowest in Venezuela (0.9%) among the analyzed cohorts.Conclusion: Nearly, 10.5%–53% of patients with COVID-19 have GI manifestations. Differential clinical symptoms were associated with COVID-19 in Latin America countries. Metabolic syndrome components were the main comorbidities associated with poor outcome. Country-specific management and prevention plans are needed. Country-specific management and prevention plans can be established from this meta-analysis.

The COVID-19 pandemic has widespread economic and social effects on Latin America (LA) and the Caribbean (CA). This region, which has a high prevalence of chronic diseases, has been one of the most affected during the pandemic. Multiple symptoms and comorbidities are related to distinct COVID-19 outcomes. However, there has been no explanation as to why different patients present with different arrays of clinical presentations. Studies report that similar to comorbidities, each country in LA and the CA has its own particular health issues. Moreover, economic and social features have yet to be studied in detail to obtain a complete perspective of the disease in the region. Herein, the impact of demographic and economic characteristics in LA and the CA on COVID-19 are presented in combination with symptoms and comorbidities related to the disease as important aspects that can influence management and treatment.

Hepatitis C virus (HCV) is a lipid-enveloped virion particle that causes infection to the liver, and as part of its life cycle, it disrupts the host lipid metabolic machinery, particularly the cholesterol synthesis pathway. The innate immune response generated by liver resident immune cells is responsible for successful viral eradication. Unfortunately, most patients fail to eliminate HCV and progress to chronic infection. Chronic infection is associated with hepatic fat accumulation and inflammation that triggers fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Despite that the current direct-acting antiviral agents have increased the cure rate of HCV infection, viral genotype and the host genetic background influence both the immune response and lipid metabolism. In this context, recent evidence has shown that cholesterol and its derivatives such as oxysterols might modulate and potentialize the hepatic innate immune response generated against HCV. The impairment of the HCV life cycle modulated by serum cholesterol could be relevant for the clinical management of HCV-infected patients before and after treatment. Alongside, cholesterol levels are modulated either by genetic variations in IL28B, ApoE, and LDLR or by dietary components. Indeed, some nutrients such as unsaturated fatty acids have demonstrated to be effective against HCV replication. Thus, cholesterol modifications may be considered as a new adjuvant strategy for HCV infection therapy by providing a biochemical tool that guides treatment decisions, an improved treatment response and favoring viral clearance. Herein, the mechanisms by which cholesterol contributes to the immune response against HCV infection and how genetic and environmental factors may affect this role are reviewed.

Bilirubin (BR), a metabolite with increased concentrations in plasma during viral hepatitis, has been recognized as a potential immune-modulator. We recently reported that conjugated BR (CB) augments regulatory T cell (Treg) suppressor activity during acute hepatitis A virus (HAV) infection. However, the mechanisms related to the effects of CB on Treg function in the course of hepatotropic viral diseases have not been elucidated. T cell immunoglobulin domain and mucin domain 3 (TIM-3), via its interactions with galectin-9 (GAL-9), is a receptor associated with enhanced Treg function. Thus, TIM-3 expression may be related to the crosstalk between CB and Tregs during HAV infection. Herein, in vitro treatment with high concentrations of CB upregulated TIM-3 expression on Tregs from healthy donors. CB treatment in vitro did not induce de novo Treg generation, and in vitro stimulation with TGF-β, which shows increased secretion during HAV infection, resulted in a trend toward increased TIM-3 expressio...

Objective: We aimed to detect and characterize hepatitis E virus (HEV) RNA in sera samples from a pediatric population infected with the hepatitis A virus (HAV) exhibiting acute hepatitis and to correlate the infection status with the clinical outcome. Methods: Seventy-five ELISA-positive samples from children containing anti-HAV and anti-HEV IgM were used to amplify and characterize partial regions within HEV ORF2. A statistical comparison of clinical data between HEV IgM-positive/HEV RNA-positive patients and HEV IgM-positive/HEV RNA-negative patients was performed. Results: Thirteen out of 75 IgM-positive samples provided amplification of discrete regions of the HEV genome. Nested RT-PCR-based detection and subsequent sequencing of 5 samples confirmed the identity of HEV genotype 1 (G1), which had not been previously reported in Mexico. Though not significant, a trend towards exacerbated clinical manifestations was found in HEV RNA-positive patients relative to HEV RNA-negative patients. Conclusions: An elevated rate of G1 RNA was detected. Hepatitis E seems to be a neglected disease in Mexico and epidemic strains of HEV are likely to play a role as causative agents of acute hepatitis in highly exposed children. Although HAV is endemic in Mexico, an HEV-RNA detection rate of 17% in co-infected samples shows the need for screening for HEV as a part of future vaccination strategies.

The symposium "Epidemiology of Hepatitis E virus (HEV) Infection and Associated Immune Response" was held at the Universidad de Guadalajara, Mexico, on 14 June 2017, to define the status of research on HEV infection in three countries in Latin America and the Caribbean (LAC)-Cuba, Mexico, and Uruguay-compared to the situation in Germany. Scientists identified specific research gaps in understanding HEV transmission and the resulting impact on development of disease in the three abovementioned LAC countries. Specific recommendations for implementing standardized serologic and molecular diagnostic methods and epidemiologic, basic, and applied research aimed to develop prevention and handling strategies for this infection, along with the associated comorbidities in the three LAC countries, were also discussed. Given similar demographic, sanitary, and economic conditions in other LAC countries that could predispose them to be at high risk for HEV transmission and infection, these research gaps and recommendations might apply to the entire LAC region. This report was -prepared by meeting participants based on 1) symposium presentations, 2) literature reviews, and 3) group discussions.El 14 de junio del 2017 se realizó en la Universidad de Guadalajara (México) un simposio sobre las características epidemiológicas de la infección por el virus de la hepatitis E (VHE) y la respuesta inmunitaria asociada. El objetivo fue definir el estado de las investigaciones sobre la infección por el VHE en tres países de América Latina y el Caribe —Cuba, México y Uruguay— en comparación con la situación en Alemania. Los científicos señalaron que para comprender la transmisión del VHE y la consiguiente repercusión en el avance de la infección en estos tres países latinoamericanos aún faltan investigaciones sobre ciertos temas específicos. También analizaron recomendaciones concretas para poner en práctica métodos estandarizados de diagnóstico serológico y molecular, y realizar investigaciones epidemiológicas, básicas y aplicadas a fin de elaborar estrategias de prevención y tratamiento de esta infección y las comorbilidades asociadas en los tres países antes mencionados. Considerando que otros países de América Latina y el Caribe presentan condiciones demográficas, sanitarias y económicas similares que podrían implicar una predisposición a un riesgo alto de transmisión del VHE y de infección por este virus, este análisis sobre las brechas y recomendaciones en el ámbito de la investigación podría aplicarse en toda la subregión. El presente informe fue elaborado por los participantes del simposio sobre la base de: 1) presentaciones del simposio; 2) revisiones bibliográficas; y 3) debates en grupos.

Summary: The post antiretroviral therapy (ART) era for human immunodeficiency virus (HIV) infection resulted in a dramatically increased proportion of deaths attributed to liver-related causes in patients with HIV treated with ART. Additionally, as patients become older as a result of effective ART, liver-related conditions and application of safe therapies are now major concerns in the setting of HIV infection.

Based on high seroprevalence, null surveillance, and lack of diagnostics, Mexico is a high-risk region for hepatitis E Virus (HEV) infection. However, few local news on infection are available. Clinicians and general population are in need of increasing awareness, and preventive measures should be emphasized.

We recently reported an immune-modulatory role of conjugated bilirubin (CB) in hepatitis A virus (HAV) infection. During this infection the immune response relies on CD4+ T lymphocytes (TLs) and it may be affected by the interaction of HAV with its cellular receptor (HAVCR1/TIM-1) on T cell surface. How CB might affect T cell function during HAV infection remains to be elucidated. Herein,in vitrostimulation of CD4+ TLs from healthy donors with CB resulted in a decrease in the degree of intracellular tyrosine phosphorylation and an increase in the activity of T regulatory cells (Tregs) expressing HAVCR1/TIM-1. A comparison between CD4+ TLs from healthy donors and HAV-infected patients revealed changes in the TCR signaling pathway relative to changes in CB levels. The proportion of CD4+CD25+ TLs increased in patients with low CB serum levels and an increase in the percentage of Tregs expressing HAVCR1/TIM-1 was found in HAV-infected patients relative to controls. A low frequency of 157insMTTTVP insertion in the viral receptor geneHAVCR1/TIM-1was found in patients and controls. Our data revealed that, during HAV infection, CB differentially regulates CD4+ TLs and Tregs functions by modulating intracellular pathways and by inducing changes in the proportion of Tregs expressing HAVCR1/TIM-1.

Hepatitis A virus (HAV) is the most common cause of acute viral hepatitis worldwide. The virus is mainly transmitted via the fecaloral route and, the incidence of infection is closely related to low socioeconomic conditions and poor sanitation. Mexico, previously categorized an area of high endemicity for HAV infection, is undergoing epidemiological transition. However, a limited number of HAV-related scientific reports regarding to virus burden is available. According to the local government health agency (Secretarla de Salud, SSA in Spanish), from 1994 to 2017 a reduction in the incidence of hepatitis related to HAV has been reported. However, HAV is still the most common cause of viral hepatitis in the country, and the pediatric population is the most prone to be infected with this virus. The analysis of the SSA data reveals that most of the reported cases from 1994 to 2017 were found in highly industrialized states. This information contradicts the documented relationship between the highest prevalence of infection and the lowest socio-economic status, and supports the necessity of viral detection and notification of HAV cases. Moreover, in spite that four HAV vaccines are available in Mexico and universal vaccination has been shown to be beneficial in developing countries in terms of declining endemicity, HAV vaccination is not mandatory in Mexico. In this review, preventive strategies including appropriate diagnosis, vaccination and public health policies on the basis of the epidemiologic status of HAV in Mexico are discussed.

Human immunodeficiency virus (HIV) predisposes for liver damage during coinfection with hepatitis E virus (HEV) and increases the replication of hepatitis C virus (HCV). HIV-hepatitis B virus (HBV) coinfections are common. In Mexico, hepatotropic viruses are major causative agents of liver disease. However, information on HIV coinfections is limited in the country.