Association between proinflammatory cytokines and lipid peroxidation in patients with severe dengue disease around defervescence

Lipid Peroxidation via Regulating the Metabolism of Docosahexaenoic Acid and Arachidonic Acid in Autistic Behavioral Symptoms

The association between the lipid peroxidation product malondialdehyde (MDA)-modified low-density lipoprotein (MDA-LDL) and the pathophysiology of autism spectrum disorder (ASD) is unclear. This association was studied in 17 children with ASD and seven age-matched controls regarding autistic behaviors. Behavioral symptoms were assessed using the Aberrant Behavior Checklist (ABC). To compensate for the small sample size, adaptive Lasso was used to increase the likelihood of accurate prediction, and a coefficient of variation was calculated for suitable variable selection. Plasma MDA-LDL levels were significantly increased, and plasma SOD levels were significantly decreased in addition to significantly increased plasma docosahexaenoic acid (DHA) levels and significantly decreased plasma arachidonic acid (ARA) levels in the 17 subjects with ASD as compared with those of the seven healthy controls. The total ABC scores were significantly higher in the ASD group than in the control group. The results of multiple linear regression and adaptive Lasso analyses revealed an association between increased plasma DHA levels and decreased plasma ARA levels, which were significantly associated with total ABC score and increased plasma MDA-LDL levels. Therefore, an imbalance between plasma DHA and ARA levels induces ferroptosis via lipid peroxidation. Decreased levels of α-linolenic acid and γ-linolenic acid may be connected to the total ABC scores with regard to lipid peroxidation.

Metabolic response to CNS infection with flaviviruses

Flaviviruses are arthropod-borne RNA viruses found worldwide that, when introduced into the human body, cause diseases, including neuroinfections, that can lead to serious metabolic consequences and even death. Some of the diseases caused by flaviviruses occur continuously in certain regions, while others occur intermittently or sporadically, causing epidemics. Some of the most common flaviviruses are West Nile virus, dengue virus, tick-borne encephalitis virus, Zika virus and Japanese encephalitis virus. Since all the above-mentioned viruses are capable of penetrating the blood-brain barrier through different mechanisms, their actions also affect the central nervous system (CNS). Like other viruses, flaviviruses, after entering the human body, contribute to redox imbalance and, consequently, to oxidative stress, which promotes inflammation in skin cells, in the blood and in CNS. This review focuses on discussing the effects of oxidative stress and inflammation resulting from pathogen invasion on the metabolic antiviral response of the host, and the ability of viruses to evade the consequences of metabolic changes or exploit them for increased replication and further progression of infection, which affects the development of sequelae and difficulties in therapy.

The elucidation of plasma lipidome profiles during severe influenza in a mouse model

Although influenza virus infection has been shown to affect lipid metabolism, details remain unknown. Therefore, we elucidated the kinetic lipid profiles of mice infected with different doses of influenza virus A/Puerto Rico/8/34 (H1N1) (PR8) by measuring multiple lipid molecular species using untargeted lipidomic analysis. C57BL/6 male mice were intranasally infected with PR8 virus at 50 or 500 plaque-forming units to cause sublethal or lethal influenza, respectively. Plasma and tissue samples were collected at 1, 3, and 6 days post-infection (dpi), and comprehensive lipidomic analysis was performed using high-performance liquid chromatography-linear trap quadrupole-Orbitrap mass spectrometry, as well as gene expression analyses. The most prominent feature of the lipid profile in lethally infected mice was the elevated plasma concentrations of phosphatidylethanolamines (PEs) containing polyunsaturated fatty acid (PUFA) at 3 dpi. Furthermore, the facilitation of PUFA-containing phospholipid production in the lungs, but not in the liver, was suggested by gene expression and lipidomic analysis of tissue samples. Given the increased plasma or serum levels of PUFA-containing PEs in patients with other viral infections, especially in severe cases, the elevation of these phospholipids in circulation could be a biomarker of infection and the severity of infectious diseases.

Liver immunopathogenesis in fatal cases of dengue in children: detection of viral antigen, cytokine profile and inflammatory mediators

Introduction

Dengue virus (DENV), the etiologic agent of dengue fever illness, represents a global public health concern, mainly in tropical and subtropical areas across the globe. It is well known that this acute viral disease can progress to severe hemorrhagic stages in some individuals, however, the immunopathogenic basis of the development of more severe forms by these patients is yet to be fully understood.

Objective

In this context, we investigated and characterized the histopathological features as well as the cytokine profile and cell subpopulations present in liver tissues from three fatal cases of DENV in children.

Methods

Hematoxylin and Eosin, Periodic Acid Schiff and Picro Sirius Red staining were utilized for the histopathological analysis. Immunohistochemistry assay was performed to characterize the inflammatory response and cell expression patterns.

Results

Vascular dysfunctions such as hemorrhage, vascular congestion and edema associated with a mononuclear infiltrate were observedin all three cases. Liver tissues exhibited increased presence of CD68+ and TCD8+ cells as well as high expression of MMP-9, TNF-a, RANTES, VEGFR-2 mediators. Viral replication was confirmed by the detection of NS3 protein.

Conclusion

Taken together, these results evidenced key factors that may be involved in the development of severe alterations in liver tissues of children in response to DENV infection.

Combined Training Reduces Redox and Inflammatory Biomarkers and Improves General-Social Health in Elderly Men

Background: Increased inflammation and oxidative stress are the main causes of many common diseases of old age. Objectives: The aim of the present study was to evaluate the effects of combined training on inflammatory and oxidative markers and the general-social health of overweight older male adults. Methods: In this quasi-experimental study, 40 overweight older male adults with an age range of 60 - 75 years were purposefully selected and randomly divided into two training and control groups. The training program included aerobic, resistance, and balance training for eight weeks and three days a week. Study variables were measured 48 hours before and after the intervention. The statistical analysis of the data was done by two-way repeated measure analysis of variance and Tukey's post hoc tests at a significance level of P ≤ 0.05. Results: After eight weeks of combined training, levels of TNF-α (P ≤ 0.01), hs-CRP (P ≤ 0.03), and MDA (P ≤ 0.01), the mass of fat (P ≤ 0.04) decreased, while the level of superoxide dismutase (P ≤ 0.01) and the score of social health (P ≤ 0.01) increased significantly. Conclusions: It seems that combined training in the elderly is a suitable option for modulating and regulating inflammatory and oxidative biomarkers and improving general social health.

Differential expression of interferon inducible protein: Guanylate binding protein (GBP1 & GBP2) in severe dengue

Dengue virus is reported to activate endothelial cells (EC), but the precise cause for severe dengue (SD) is not known. Guanylate binding proteins (GBPs) are IFN-inducible proteins secreted by ECs and are involved in the anti-oxidant and anti-viral response. The involvement of GBPs in the pathogenesis of dengue remains under explored. In the present study, we quantified the mRNA and protein levels of GBP1 and 2 during acute, defervescence and convalescent phase in SD-10, dengue without warning sign-15 and dengue with warning sign-25 compared to other febrile illnesses-10 and healthy controls-8 using RT-PCR and ELISA respectively. Lipid peroxidation in plasma samples were measured using the Kei Satoh method. Protein and DNA oxidation were determined by ELISA. The efficacy of the proteins in predicting disease severity was done by Support Vector Machine (SVM) model. A significant (P ≤ 0.01) decrease in the levels of mRNA and protein of both GBP1 and GBP2 was observed during defervescence in both SD and DWW cases. The levels were significantly (P ≤ 0.05) tapered off in SD cases from acute till critical phases compared to other study groups. DNA, protein and lipid oxidation markers showed an increasing trend in SD (P ≤ 0.01). Both GBP1 & 2 were found to be negatively associated plasma leakage and oxidative stress markers. EC's activated with SD serum showed a reduced expression of GBP 1 and 2. Nevertheless, the SVM model revealed that plasma levels of proteins along with clinical symptoms could predict the disease outcomes with higher precision. This is the first study reporting a downregulated expression of GBP1 & 2 and their association with oxidative stress and plasma leakage in dengue cases. This suggests the importance of GBPs in regulating disease manifestation. However, further investigations are required to ascertain its role as a biomarker or therapeutic target in dengue infection.

Micro-Raman spectroscopy study of optically trapped erythrocytes in malaria, dengue and leptospirosis infections

Malaria, dengue and leptospirosis are three tropical infectious diseases that present with severe hematological derangement causing significant morbidity and mortality, especially during the seasonal monsoons. During the course of these infectious diseases, circulating red blood cells are imperiled to the direct ill-effects of the infectious pathogen in the body as well as to the pro-inflammatory cytokines generated as a consequence of the infection. RBCs when exposed to such inflammatory and/or pathogenic milieu are susceptible to injuries such as RBC programmed eryptosis or RBC programmed necrosis. This research aimed to explore the Raman spectra of live red cells that were extracted from patients infected with malaria, dengue, and leptospirosis. Red cells were optically trapped and micro-Raman probed using a 785 nm Diode laser. RBCs from samples of all three diseases displayed Raman signatures that were significantly altered from the normal/healthy. Distinct spectral markers that were common across all the four groups were obtained from various standardized multivariate analytical methods. Following comprehensive examination of multiple studies, we propose these spectral wavenumbers as "Raman markers of RBC injury." Findings in our study display that anemia-triggering infections can inflict variations in the healthy status of red cells, easily identifiable by selectively analyzing specific Raman markers. Additionally, this study also highlights relevant statistical tools that can be utilized to study Raman spectral data from biological samples which could help identify the very significant Raman peaks from the spectral band. This approach of RBC analysis can foster a better understanding of red cell behavior and their alterations exhibited in health and disease.

Can Biomarkers of Oxidative Stress in Serum Predict Disease Severity in West Nile Virus Infection? A Pilot Study

West Nile virus (WNV) can cause asymptomatic infection in humans, result in self-limiting febrile illness, or lead to severe West Nile Neuroinvasive disease (WNND). We conducted a pilot study to compare selected biomarkers of oxidative stress in sera of viremic West Nile virus patients and asymptomatic infected blood donors to investigate their potential as predictors of disease severity. We found that total oxidant status was elevated in WNND and in uncomplicated WNV infections (median 9.05 (IQR 8.37 to 9.74) and 7.14 (7.03 to 7.25) µmol H2O2 equiv./L, respectively) compared to asymptomatic infections (0.11 (0.07 to 0.19) µmol H2O2 equiv./L) (p = 0.048). MDA levels showed a similar trend to TOS, but differences were not significant at α = 0.05. Total antioxidant status did not differ significantly between different disease severity groups. Oxidative stress appears to be associated with more severe disease in WNV-infected patients. Our preliminary findings warrant prospective studies to investigate the correlation of oxidative stress with clinical outcomes and severity of WNV infection.

Oxidative stress, biochemical, and histopathological changes associated with acute lumpy skin disease in cattle

Background and Aim:

Lumpy skin disease (LSD) is a highly infectious endemic viral disease of cattle in Africa and the Middle East. The objectives of this study were to assess histopathological changes in cattle infected with LSD and measure serum malondialdehyde (MDA – oxidant) and total anti-oxidant capacity (TAC – anti-oxidant), trace elements (zinc, copper, and iron), cytokines (interleukin [IL]-1β, IL-6, and tumor necrosis factor-alpha [TNF-α]), haptoglobin (Hp), serum amyloid A (SAA), aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine phosphokinase (CPK), blood urea nitrogen (BUN), and creatinine concentrations.

Materials and Methods:

Blood samples were collected from a total of sixty native and mixed breed cattle; (healthy; n = 25) and (LSD diseased; n = 35). Serum concentrations of MDA and TAC were measured by colorimetric methods. Serum IL-1β, IL-6, IL-10, TNF-α, Hp, and SAA concentrations were determined using human-specific enzyme-linked immunoassay kits.

Results:

Serum MDA, cytokine (IL-1β, IL-6, and TNF-α), Hp, SAA, AST, ALT, CPK, BUN, and creatinine concentrations were significantly higher, while TAC, IL-10, zinc, copper, and iron concentrations were significantly lower in LSD compared to healthy cattle (p < 0.05). Cows and exotic mixed breed cattle were at higher risk of LSD oxidative stress than bulls and local breeds (p < 0.05). Age was not associated with the risk of LSD (p > 0.05). Histologically, there was extensive tissue necrosis, severe vasculitis, mononuclear cell infiltration, and intracytoplasmic inclusion bodies.

Conclusion:

LSD is associated with pro-oxidative and pro-inflammatory states from imbalances that favor pro-oxidant and pro-inflammatory factors in the detriment of anti-oxidant and anti-inflammatory factors, leading to organ dysfunction and ultimately death. Oxidative stress is more frequent in cows and mixed breed cattle than in bulls and local breeds.

Oxidative stress and associated clinical manifestations in malaria and sickle cell (HbSS) comorbidity

In Ghana, uncomplicated malaria and sickle cell disease (SCD) is common, hence comorbidity is not farfetched. However, the extent of oxidative stress and the array of clinical manifestations in this comorbidity (presence of both malaria and SCD) has not been fully explored. This study highlights the impact of uncomplicated malaria on SCD. The level of isoprostane, 8-iso-prostaglandin F2α (8-iso-PGF2α) was used to assess oxidative stress while plasma biochemistry and urinalysis was used to assess renal function. Hematological profiling was also done to assess the impact of comorbidity on the hematological cell lines. Of the 411 study participants with malaria, 45 (11%) had SCD. Mean body temperature was significantly higher in comorbidity compared to malaria and SCD cohorts, while a lower parasite density range was obtained in comorbidity compared to malaria cohorts. Furthermore, in comorbidity, the 8-iso-PGF2α oxidative stress biomarker was significantly elevated in all ages, parasite density ranges and gender groups. Comorbidity affected both leukocytic and erythrocytic cell lines with significant eosinophilia and monocytosis coexisting with erythrocytic parameters consistent with severe anemia. Biochemically, while plasma creatinine and bilirubin were significantly elevated in comorbidity, spot urinary creatinine was significantly reduced. Additionally, urine samples in the comorbid state were slightly acidic and hypersthenuric with significant hematuria, proteinuria, and bilirubinemia. Finally, 80% or more malaria-SCD presented with chills, fever, anorexia, headache, joint pains, lethargy, and vomiting. In conclusion, malaria could induce vaso-occlusive crisis in sickle cell disease, therefore, prompt management will alleviate the severity of this comorbidity.

Neutralizing the free radicals could alleviate the disease severity following an infection by positive strand RNA viruses

Free radical release due to oxidative stress is gaining importance in the field of viral pathogenesis. Recent studies suggest the involvement of oxidative stress and ROS levels in regulating disease virulence during RNA virus infection. Most of the RNA virus infections lead to vascular dysfunction and disease severity. However, the biology of free radicals in maintaining vascular endothelium integrity is not completely understood. In the present review, we discuss some of the common features in positive-strand RNA virus infections such as dengue and SARS-CoV-2 and suggest that anti-oxidant therapy could pave the way to develop therapeutic strategies in combating emerging and re-emerging RNA viruses.

Risk and predictive factors for severe dengue infection: A systematic review and meta-analysis

Background

Dengue is a major public health issue worldwide and severe dengue (SD) is life threatening. It is critical to triage patients with dengue infection in the early stage. However, there is limited knowledge on early indicators of SD. The objective of this study is to identify risk factors for the prognosis of SD and try to find out some potential predictive factors for SD from dengue fever (DF) in the early of infection.

Methods

The PubMed, Cochrane Library and Web of Science databases were searched for relevant studies from June 1999 to December 2020. The pooled odds ratio (OR) or standardized mean difference (SMD) with 95% confidence intervals (CI) of identified factors was calculated using a fixed or random effect model in the meta-analysis. Tests for heterogeneity, publication bias, subgroup analyses, meta-regression, and a sensitivity analysis were further performed.

Findings

A total of 6,848 candidate articles were retrieved, 87 studies with 35,184 DF and 8,173 SD cases met the eligibility criteria. A total of 64 factors were identified, including population and virus characteristics, clinical symptoms and signs, laboratory biomarkers, cytokines, and chemokines; of these factors, 34 were found to be significantly different between DF and SD, while the other 30 factors were not significantly different between the two groups after pooling the data from the relevant studies. Additionally, 9 factors were positive associated with SD within 7 days after illness when the timing subgroup analysis were performed.

Conclusions

Practical factors and biomarkers for the identification of SD were established, which will be helpful for a prompt diagnosis and early effective treatment for those at greatest risk. These outcomes also enhance our knowledge of the clinical manifestations and pathogenesis of SD.

Infection of Endothelial Cells by Dengue Virus Induces ROS Production by Different Sources Affecting Virus Replication, Cellular Activation, Death and Vascular Permeability

Exacerbated inflammatory response and altered vascular function are hallmarks of dengue disease. Reactive oxygen species (ROS) production has been associated to endothelial barrier disturbance and microvascular alteration in distinct pathological conditions. Increased ROS has been reported in in vitro models of dengue virus (DENV) infection, but its impact for endothelial cell physiology had not been fully investigated. Our group had previously demonstrated that infection of human brain microvascular endothelial cells (HBMEC) with DENV results in the activation of RNA sensors and production of proinflammatory cytokines, which culminate in cell death and endothelial permeability. Here, we evaluated the role of mitochondrial function and NADPH oxidase (NOX) activation for ROS generation in HBMEC infected by DENV and investigated whether altered cellular physiology could be a consequence of virus-induced oxidative stress. DENV-infected HBMECs showed a decrease in the maximal respiratory capacity and altered membrane potential, indicating functional mitochondrial alteration, what might be related to mtROS production. Indeed, mtROS was detected at later time points after infection. Specific inhibition of mtROS diminished virus replication, cell death, and endothelial permeability, but did not affect cytokine production. On the other hand, inhibition of NOX-associated ROS production decreased virus replication and cell death, as well as the secretion of inflammatory cytokines, including IL-6, IL-8, and CCL5. These results demonstrated that DENV replication in endothelial cells induces ROS production by different pathways, which impacts biological functions that might be relevant for dengue pathogenesis. Those data also indicate oxidative stress events as relevant therapeutical targets to avoid vascular permeability, inflammation, and neuroinvasion during DENV infection.

The Seroprevalence of Dengue Virus Infection and Its Association With Iron (Fe) Level in Pregnant Women in Guangzhou, China

Dengue fever is regarded as the most prevalent mosquito-borne viral disease in humans. However, information of dengue virus (DENV) infection in pregnant women and the influence factors remain unclear. In this study, we extracted information of 2,076 pregnant women from the Prenatal Environment and Offspring Health (PEOH) birth cohort conducted since 2016 in Guangzhou, China. Peripheral blood and clean midstream urine samples of participants were collected during their hospitalization for childbirth. Indirect enzyme-linked immunosorbent assay (ELISA) was used to detect immunoglobulin G (IgG) antibodies of DENV in serum samples, and inductively coupled plasma mass spectrometry (ICP-MS) was applied to determine the Fe concentrations in the urine samples, which were then adjusted for by urine creatinine and transformed by natural logarithm (ln-Fe). The seroprevalence of DENV IgG antibody in all included participants was 2.22% (46/2,076). We observed higher seroprevalence of IgG antibody in women aged ≥35 years (2.9%), education ≤ 12 years (2.5%), yearly income per capita <100,000 yuan (2.4%), no use of air-conditioner (2.4%), no use of mosquito coils (2.3%), and no exercise during pregnancy (4.1%). A U-shaped relationship was found between ln-Fe concentration and the risk of positive IgG antibody. Compared with women with ln-Fe concentration of 2.0–2.9 μg/g creatinine, slightly higher risks of positive IgG antibody were found among women with ≤2.0 (RR = 4.16, 95% CI: 0.78, 19.91), 3.0–3.9 (RR = 1.93, 95% CI: 0.65, 7.08), 4.0–4.9 (RR = 2.19, 95% CI: 0.65, 8.51), and ≥5.0 μg/g creatinine of ln-Fe (RR = 2.42, 95% CI: 0.46, 11.33). Our findings suggested that the seroprevalence of dengue IgG antibody in pregnant women was comparable to the general population in Guangzhou, China. The risk of DENV infection may be associated with maternal demographic characteristics and behaviors. Both maternal low and high Fe concentrations may be positively associated with the risk of DENV infection.

Increased Lipid Peroxidation May Be Linked to Ferritin Levels Elevation in Adult-Onset Still's Disease

Lipid peroxidation (LPO) and hyper-ferritinemia are involved in inflammatory responses. Although hyper-ferritinemia is a characteristic of AOSD, its link to LPO remains unclear. We investigated the association between LPO and ferritin expression, and evaluated the relationship between LPO-related metabolites and inflammatory parameters. Mean fluorescence intensity (MFI) of LPO (C11-Biodipy^581/591)-expressing PBMCs/monocytes in AOSD patients and healthy control (HC) subjects was determined by flow-cytometry analysis. Expression of ferritin and cytokines on PBMCs/macrophages was examined by immunoblotting. Plasma levels of LPO-related metabolites and cytokines were determined by ELISA and the MULTIPLEX platform, respectively. LPO MFI on PBMCs/monocytes were significantly higher in patients (median 4456 and 9091, respectively) compared with HC (1900, p < 0.05, and 4551, p < 0.01, respectively). Patients had higher ferritin expression on PBMCs (mean fold, 1.02) than HC (0.55, p < 0.05). Their ferritin expression levels on PBMCs stimulated with LPO inducers erastin or RSL3 (2.47 or 1.61, respectively) were higher than HC (0.84, p < 0.05, or 0.74, p < 0.01). Ferritin expression on erastin-treated/IL-1β-treated macrophages from patients were higher than those from HC (p < 0.001). The elevated levels of LPO-related metabolites, including malondialdehyde and 4-hydroxyalkenals, were positively correlated with disease activity scores, suggesting LPO involvement in AOSD pathogenesis. Increased ferritin expression on PBMCs/macrophages stimulated with LPO inducers indicates a link between LPO and elevated ferritin.

Regulation of innate immune responses in macrophages differentiated in the presence of vitamin D and infected with dengue virus 2

A dysregulated or exacerbated inflammatory response is thought to be the key driver of the pathogenesis of severe disease caused by the mosquito-borne dengue virus (DENV). Compounds that restrict virus replication and modulate the inflammatory response could thus serve as promising therapeutics mitigating the disease pathogenesis. We and others have previously shown that macrophages, which are important cellular targets for DENV replication, differentiated in the presence of bioactive vitamin D (VitD3) are less permissive to viral replication, and produce lower levels of pro-inflammatory cytokines. Therefore, we here evaluated the extent and kinetics of innate immune responses of DENV-2 infected monocytes differentiated into macrophages in the presence (D3-MDMs) or absence of VitD3 (MDMs). We found that D3-MDMs expressed lower levels of RIG I, Toll-like receptor (TLR)3, and TLR7, as well as higher levels of SOCS-1 in response to DENV-2 infection. D3-MDMs produced lower levels of reactive oxygen species, related to a lower expression of TLR9. Moreover, although VitD3 treatment did not modulate either the expression of IFN-α or IFN-β, higher expression of protein kinase R (PKR) and 2'-5'-oligoadenylate synthetase 1 (OAS1) mRNA were found in D3-MDMs. Importantly, the observed effects were independent of reduced infection, highlighting the intrinsic differences between D3-MDMs and MDMs. Taken together, our results suggest that differentiation of MDMs in the presence of VitD3 modulates innate immunity in responses to DENV-2 infection.

Expression dynamics of vascular endothelial markers: endoglin and syndecan-1 in predicting dengue disease outcome

Plasma leakage is a hallmark process in dengue viral (DENV) infection that occurs due to the loss of vascular integrity in endothelial cells. Endoglin (ENG) and Syndecan-1 (SDC-1) are released by activated endothelial cells; however, the complete dynamics of its expression at the gene and protein levels during the course of DENV infection remains unknown. In the present study, we quantified the mRNA and soluble protein levels of ENG and SDC-1 in dengue cases during febrile, defervescence, and convalescence stages in Dengue without Warning Sign (DWOW-15), Dengue with Warning Sign (DWW-22), and Severe Dengue cases (SD-10) compared to nondengue Other Febrile Illness (OFI-10) and healthy control (HC-8). Respective protein and mRNA levels along with clinical characters were further analyzed for their efficacy in predicting disease outcomes using Support Vector Machine (SVM). We observed a steady and significant (P ≤ 0.01) increase in the levels of protein and mRNA of both the ENG and SDC-1 towards defervescence which is considered a critical phase in both severe and non-severe dengue cases. Importantly during the critical phase, the levels were significantly higher (P ≤ 0.001) in SD cases compared to DWW, DWOW, and OFI controls. However, at the time of admission (febrile), no such significant changes were observed within dengue, OFI, and healthy controls. SVM analysis revealed that the serum levels of ENG and SDC-1 along with other clinical symptoms could predict the disease severity with 100% accuracy. Based on the results we have proposed a mechanism on how ENG and SDC-1 could be involved in vascular dysfunction rather than just being a biomarker.

(E)-Guggulsterone Inhibits Dengue Virus Replication by Upregulating Antiviral Interferon Responses through the Induction of Heme Oxygenase-1 Expression

Dengue virus (DENV) infection, which causes dengue fever, dengue hemorrhagic fever, and dengue shock syndrome, is a severe global health problem in tropical and subtropical areas. There is no effective vaccine or drug against DENV infection. Thus, the development of anti-DENV agents is imperative. This study aimed to assess the anti-DENV activity of (E)-guggulsterone using a DENV infectious system. A specific inhibitor targeting signal molecules was used to evaluate the molecular mechanisms of action. Western blotting and qRT-PCR were used to determine DENV protein expression and RNA replication, respectively. Finally, an ICR suckling mouse model was used to examine the anti-DENV activity of (E)-guggulsterone in vivo. A dose-dependent inhibitory effect of (E)-guggulsterone on DENV protein synthesis and RNA replication without cytotoxicity was observed. The mechanistic studied revealed that (E)-guggulsterone stimulates Nrf2-mediated heme oxygenase-1 (HO-1) expression, which increases the antiviral interferon responses and downstream antiviral gene expression by blocking DENV NS2B/3B protease activity. Moreover, (E)-guggulsterone protected ICR suckling mice from life-threatening DENV infection. These results suggest that (E)-guggulsterone can be a potential supplement for controlling DENV replication.

Alpha-mangostin inhibits dengue virus production and pro-inflammatory cytokine/chemokine expression in dendritic cells

Dengue virus (DENV) is transmitted to humans via the bite of an Aedes mosquito, causing dengue fever, dengue hemorrhagic fever, or dengue shock syndrome. In the human skin, DENV first infects keratinocytes, dendritic cells, and macrophages. Monocytes that are recruited to the site of infection and differentiate into monocyte-derived dendritic cells (moDCs) are also infected by DENV. DENV-infected DCs secrete pro-inflammatory cytokines and chemokines to modulate the immune response. The viral load and massive pro-inflammatory cytokine/chemokine production, referred to as a 'cytokine storm', are associated with disease severity. We propose that an ideal drug for treatment of DENV infection should inhibit both virus production and the cytokine storm, and previously, we reported that alpha-mangostin (α-MG) inhibits both DENV replication and cytokine production in hepatocytes. However, the effect of α-MG on DENV-infected moDCs remains unknown. In this study, we investigated the effects of α-MG on DENV infection and pro-inflammatory cytokine/chemokine production in primary moDCs generated ex vivo from monocytes of healthy individuals. α-MG at the non-toxic concentrations of 20 and 25 μM reduced DENV production by more than 10-fold and 1,000-fold, respectively. Treatment with α-MG efficiently inhibited the infection of immature moDCs by all four serotypes of DENV. Time-of-addition studies suggested that α-MG (25 μM) inhibits DENV at the early stage of replication. In addition, α-MG markedly reduced cytokine/chemokine (TNF-α, CCL4, CCL5, CXCL10, IL6, IL1β, IL10, and IFN-α) transcription in DENV-infected immature moDCs. These findings suggest the potential of α-MG to be developed as a novel anti-DENV drug.

Cytokine IP-10 and GM-CSF are prognostic biomarkers for severity in secondary dengue infection

Dengue virus (DENV) infection is mostly prevalent in tropical and sub-tropical regions of the world. Though most DENV infections are self-limiting febrile like-illness, a small proportion of secondary infection is fatal, if untreated symptomatically. Among various factors involved in severe dengue, immune enhancement by cytokine is the major one. The objective of the study is to elucidate serum cytokine expression among primary and secondary infection and determine if any signature cytokine is correlated with disease severity. Seventy-six serum samples at acute time points were collected during the 2017 DENV outbreak in Madurai, Tamil Nadu. Among the 76 serum samples, 49 belong to primary and 27 to secondary DENV infection. Interestingly, a large number of primary infection presented with DHF/DSS symptoms and, children were found prone to DHF and DSS in secondary infection. The serum samples were analysed for inflammatory cytokines, namely IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-17A, IFN-γ, TNF-α, IP-10 and GM-CSF using ELISA assay as well as mRNA analysis using qPCR. Among the 12 inflammatory cytokines analysed IP-10 and GMCSF mRNA and protein shows significant upregulation in secondary infection. Similarly, a strong correlation was observed between GM-CSF and IP-10 with thrombocytopenia, ascites, serous effusion and spontaneous bleeding. Based on the observations, GM-CSF and IP-10 could be a potential prognostic biomarkers for secondary DENV infection.

Dengue Virus Targets Nrf2 for NS2B3-Mediated Degradation Leading to Enhanced Oxidative Stress and Viral Replication

Dengue virus (DENV) is a mosquito-borne virus that infects upward of 300 million people annually and has the potential to cause fatal hemorrhagic fever and shock. While the parameters contributing to dengue immunopathogenesis remain unclear, the collapse of redox homeostasis and the damage induced by oxidative stress have been correlated with the development of inflammation and progression toward the more severe forms of disease. In the present study, we demonstrate that the accumulation of reactive oxygen species (ROS) late after DENV infection (>24 hpi) resulted from a disruption in the balance between oxidative stress and the nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent antioxidant response. The DENV NS2B3 protease complex strategically targeted Nrf2 for degradation in a proteolysis-independent manner; NS2B3 licensed Nrf2 for lysosomal degradation. Impairment of the Nrf2 regulator by the NS2B3 complex inhibited the antioxidant gene network and contributed to the progressive increase in ROS levels, along with increased virus replication and inflammatory or apoptotic gene expression. By 24 hpi, when increased levels of ROS and antiviral proteins were observed, it appeared that the proviral effect of ROS overcame the antiviral effects of the interferon (IFN) response. Overall, these studies demonstrate that DENV infection disrupts the regulatory interplay between DENV-induced stress responses, Nrf2 antioxidant signaling, and the host antiviral immune response, thus exacerbating oxidative stress and inflammation in DENV infection.IMPORTANCE Dengue virus (DENV) is a mosquito-borne pathogen that threatens 2.5 billion people in more than 100 countries annually. Dengue infection induces a spectrum of clinical symptoms, ranging from classical dengue fever to severe dengue hemorrhagic fever or dengue shock syndrome; however, the complexities of DENV immunopathogenesis remain controversial. Previous studies have reported the importance of the transcription factor Nrf2 in the control of redox homeostasis and antiviral/inflammatory or death responses to DENV. Importantly, the production of reactive oxygen species and the subsequent stress response have been linked to the development of inflammation and progression toward the more severe forms of the disease. Here, we demonstrate that DENV uses the NS2B3 protease complex to strategically target Nrf2 for degradation, leading to a progressive increase in oxidative stress, inflammation, and cell death in infected cells. This study underlines the pivotal role of the Nrf2 regulatory network in the context of DENV infection.

Alterations of hemogram, serum biochemistry, oxidative/nitrosative balance, and copper/zinc homeostasis in dromedary camels naturally infected with poxvirus

Camel pox (CMLP), a contagious viral disease of camels, causes considerable economic loss in terms of milk, meat, wool, and leather production besides reduction of draught power. The effect of spontaneous CMLP infection on hemogram, oxidative/nitrosative imbalance, and trace mineral homeostasis has not been studied earlier in dromedary camels. In the current study, hemogram, serum biochemistry, oxidant/antioxidant imbalance, and zinc (Zn)-copper (Cu) homeostasis were evaluated in healthy and pox-infected camels. The CMLP was confirmed from pooled samples of vesicular fluid, oral mucosa, and skin samples by polymerase chain reaction (PCR) targeting the C18L gene of CMLP virus. Hemogram was performed manually in whole blood. The serum was analyzed for biochemistry. The oxidative/nitrosative imbalance was measured by determining the concentrations of malondialdehyde (MDA), nitrite and nitrate (NOx), and glutathione S-transferase (GST) activity in serum. Simultaneously, copper (Cu) and zinc (Zn) concentrations were measured in serum. A pronounced leucopenia (p = 0.019), lymphopenia (p = 0.005), and hypoproteinemia (p = 0.014) were noted in CMLP-infected camels compared to healthy animals. The significant elevation of the MDA (p = 0.005) and NOx (p = 0.044) concentrations in serum of CMLP-infected indicated marked oxidative stress during the disease. The zinc concentration (p = 0.014) in CMLP-infected camels was significantly lower than healthy camels. The study supports that oxidative/nitrosative imbalance and Cu-Zn homeostasis are compromised and related to the pathophysiology of CMLP infection. The finding will be helpful to veterinary clinicians to adopt effective therapeutic strategies using antioxidants and trace minerals during CMLP outbreak. The timely vaccination and bio-security will be the mainstay for prevention of the diseases.

Redox control of vascular biology

Redox control is lost when the antioxidant defense system cannot remove abnormally high concentrations of signaling molecules, such as reactive oxygen species (ROS). Chronically elevated levels of ROS cause oxidative stress that may eventually lead to cancer and cardiovascular and neurodegenerative diseases. In this review, we focus on redox effects in the vascular system. We pay close attention to the subcompartments of the vascular system (endothelium, smooth muscle cell layer) and give an overview of how redox changes influence those different compartments. We also review the core aspects of redox biology, cardiovascular physiology, and pathophysiology. Moreover, the topic-specific knowledgebase DES-RedoxVasc was used to develop two case studies, one focused on endothelial cells and the other on the vascular smooth muscle cells, as a starting point to possibly extend our knowledge of redox control in vascular biology.

Transcriptional Correlates of Tolerance and Lethality in Mice Predict Ebola Virus Disease Patient Outcomes

Host response to infection is a major determinant of disease severity in Ebola virus disease (EVD), but gene expression programs associated with outcome are poorly characterized. Collaborative Cross (CC) mice develop strain-dependent EVD phenotypes of differential severity, ranging from tolerance to lethality. We screen 10 CC lines and identify clinical, virologic, and transcriptomic features that distinguish tolerant from lethal outcomes. Tolerance is associated with tightly regulated induction of immune and inflammatory responses shortly following infection, as well as reduced inflammatory macrophages and increased antigen-presenting cells, B-1 cells, and γδ T cells. Lethal disease is characterized by suppressed early gene expression and reduced lymphocytes, followed by uncontrolled inflammatory signaling, leading to death. We apply machine learning to predict outcomes with 99% accuracy in mice using transcriptomic profiles. This signature predicts outcomes in a cohort of EVD patients from western Africa with 75% accuracy, demonstrating potential clinical utility.

Host-Based Prognostic Biomarkers to Improve Risk Stratification and Outcome of Febrile Children in Low- and Middle-Income Countries

Fever is one of the leading causes for pediatric medical consultation and the most common symptom at clinical presentation in low- and middle-income countries (LMICs). Most febrile episodes are due to self-limited infections, but a small proportion of children will develop life-threatening infections. The early recognition of children who have or are progressing to a critical illness among all febrile cases is challenging, and there are currently no objective and quantitative tools to do so. This results in increased morbidity and mortality among children with impending life-threatening infections, whilst contributing to the unnecessary prescription of antibiotics, overwhelming health care facilities, and harm to patients receiving avoidable antimicrobial treatment. Specific fever origin is difficult to ascertain and co-infections in LMICs are common. However, many severe infections share common pathways of host injury irrespective of etiology, including immune and endothelial activation that contribute to the pathobiology of sepsis (i.e., pathogen "agnostic" mechanisms of disease). Importantly, mediators of these pathways are independent markers of disease severity and outcome. We propose that measuring circulating levels of these factors can provide quantitative and objective evidence to: enable early recognition of severe infection; guide patient triage and management; enhance post-discharge risk stratification and follow up; and mitigate potential gender bias in clinical decisions. Here, we review the clinical and biological evidence supporting the clinical utility of host immune and endothelial activation biomarkers as components of novel rapid triage tests, and discuss the challenges and needs for developing and implementing such tools.

Oxidative stress response in the pathogenesis of dengue virus virulence, disease prognosis and therapeutics: an update

Dengue virus (DENV) is a mosquito-borne arbovirus that causes febrile illness and can lead to a potentially lethal disease. The mechanism of disease pathogenesis is not completely understood, and there are currently no vaccines or therapeutic drugs available to protect against all four serotypes of DENV. Although many reasons have been suggested for the development of the disease, dengue studies have shown that, during DENV infection, there is an imbalance between oxidants and antioxidants that disrupts homeostasis. An increase in reactive oxygen species (ROS) levels triggers the sudden release of cytokines, which can lead to plasma leakage and other severe symptoms. In the present review, we give an overview of the oxidative stress response and its effect on the progression of dengue disease. We also discuss the role of oxidative-stress-associated molecules in disease prognostic and therapeutics.

Highlights for Dengue Immunopathogenesis: Antibody-Dependent Enhancement, Cytokine Storm, and Beyond

Infection with dengue virus (DENV) can lead to a wide spectrum of clinical presentations, ranging from asymptomatic infection to death. It is estimated that the disease manifests only in 90 million cases out of the total 390 million yearly infections. Even though research has not yet elucidated which are the precise pathophysiological mechanisms that trigger severe forms of dengue, the infection elicits a critical immune response significant for dengue pathogenesis development. Understanding how the immune response to DENV is established and how it can resolve the infection or turn into an immunopathology is of great importance in DENV research. Currently, studies have extensively debated 2 hypotheses involving immune response: antibody-dependent enhancement and cytokine storm. However, despite its undeniable importance in severe forms of the disease, these 2 hypotheses are based on a primed immune status resulting from previous heterologous infection, abstaining them from explaining the severe forms of dengue in naive immune subjects, for example. Thus, it seems that a more intricate arrangement of causes and conditions must be achieved to severe dengue to occur. Among them, the cytokine network signature elicited, in association with viral aspects deserves special attention regarding the establishment of infection and evolution to pathogenesis. In this work, we intend to shed light on how those elements contribute to severe dengue development.

Expression Pattern of Selected Toll-like Receptors (TLR's) in the PBMC's of Severe and Non-severe Dengue Cases

Objective: The role of TLR's in the pathogenesis of dengue is not explored well. Differential expression of TLR2 and TLR4 was reported in dengue cases. In the present study in order to understand the expression pattern of various TLR's, including TLR2, TLR3, TLR4 and TLR9, mRNA levels were determined in various dengue study groups compared to control groups, at the time of admission and around defervescence using quantitative real-time PCR (RT-PCR).Methods: A total of 88 dengue cases with 32 severe and 56 non-severe cases were involved in the study. Gene expression pattern of the study groups was compared with 31 other febrile illness (OFI) cases and 63 healthy controls. Transcript levels of the target genes were estimated from the peripheral blood mononuclear cells (PBMC) samples collected from cases and controls using quantitative real-time PCR.Results: We have noted a significant alteration in the levels of all TLR's in dengue and OFI cases compared to healthy controls at the time of admission. Interestingly we have noted a significant alteration in the levels of TLR9 in severe and non-severe cases during defervescence. The same was not detected in the OFI group.Conclusion: The present study found a change in TLR's during dengue infection. This suggests us to explore the TLR's as therapeutic candidate for anti-dengue virus strategies. However, in order to ascertain the involvement of TLR's in the disease pathology and its role as biomarkers for prognosis, a complete dynamics of TLR's expression needs to be studied.

Flaviviridae Viruses and Oxidative Stress: Implications for Viral Pathogenesis

Oxidative stress is induced once the balance of generation and neutralization of reactive oxygen species (ROS) is broken in the cell, and it plays crucial roles in a variety of natural and diseased processes. Infections of Flaviviridae viruses trigger oxidative stress, which affects both the cellular metabolism and the life cycle of the viruses. Oxidative stress associated with specific viral proteins, experimental culture systems, and patient infections, as well as its correlations with the viral pathogenesis attracts much research attention. In this review, we primarily focus on hepatitis C virus (HCV), dengue virus (DENV), Zika virus (ZIKV), Japanese encephalitis virus (JEV), West Nile virus (WNV), and tick-borne encephalitis virus (TBEV) as representatives of Flaviviridae viruses and we summarize the mechanisms involved in the relevance of oxidative stress for virus-associated pathogenesis. We discuss the current understanding of the pathogenic mechanisms of oxidative stress induced by Flaviviridae viruses and highlight the relevance of autophagy and DNA damage in the life cycle of viruses. Understanding the crosstalk between viral infection and oxidative stress-induced molecular events may offer new avenues for antiviral therapeutics.

Assessment of chemokine and cytokine signatures in patients with dengue infection: A hospital-based study in Kolkata, India

Dengue fever is an acute viral infection transmitted by arthropods but may evolve to severe clinical manifestations. Descriptions of the role of circulating immune modulators such as cytokines or chemokines in dengue immunopathogenesis have largely relied on data from South-east Asia and America, while India is poorly represented. This study characterizes dengue cases from West Bengal, eastern India, with respect to clinical profile and pro-inflammatory and inflammatory cytokines. We evaluated the profile of both inflammatory and anti-inflammatory cytokines (IFNγ, IL6, IL10, IL12 and TGFβ) and chemokines (IL8, CXCL9, CXCL10 and RANTES) in 100 hospitalized NS1/IgM confirmed Dengue patients during the epidemic in West Bengal during 2017. Additionally, all necessary blood investigations of the study subjects were performed. The patients mostly hailed from Kolkata, followed by Nadia, 24 Parganas (North and South), Murshidabad and Midnapore. The most common presentations apart from fever and bodyache were gastrointestinal symptoms. An elevated levels of cytokines IL6 and IL10 chemokine IL8 and CXCL10 along with decreased RANTES were found in the patients with Severe Dengue as compared to mild forms of dengue (p < 0.0001) during 3-6 days of infections. A significant association was obtained between most of cytokine and increased SGPT, haematocrit, albumin and decreased platelet count, whereas a negative correlation with the level of RANTES to haematocrit (r=-0.220 with p = 0.029) was found in severe dengue cases with altered liver function parameters. This is the first study demonstrating cytokine and chemokine association with dengue severity from the eastern part of India. Taken together, this study demonstrated that the altered expression levels of IL6, IL10, IL8, CXCL10 and RANTES had significant associations with dengue severity parameters.

The Role of Tissue Oxygen Tension in Dengue Virus Replication

Low oxygen tension exerts a profound effect on the replication of several DNA and RNA viruses. In vitro propagation of Dengue virus (DENV) has been conventionally studied under atmospheric oxygen levels despite that in vivo, the tissue microenvironment is hypoxic. Here, we compared the efficiency of DENV replication in liver cells, monocytes, and epithelial cells under hypoxic and normoxic conditions, investigated the ability of DENV to induce a hypoxia response and metabolic reprogramming and determined the underlying molecular mechanism. In DENV-infected cells, hypoxia had no effect on virus entry and RNA translation, but enhanced RNA replication. Overexpression and silencing approaches as well as chemical inhibition and energy substrate exchanging experiments showed that hypoxia-mediated enhancement of DENV replication depends on the activation of the key metabolic regulators hypoxia-inducible factors 1α/2α (HIF-1α/2α) and the serine/threonine kinase AKT. Enhanced RNA replication correlates directly with an increase in anaerobic glycolysis producing elevated ATP levels. Additionally, DENV activates HIF and anaerobic glycolysis markers. Finally, reactive oxygen species were shown to contribute, at least in part through HIF, both to the hypoxia-mediated increase of DENV replication and to virus-induced hypoxic reprogramming. These suggest that DENV manipulates hypoxia response and oxygen-dependent metabolic reprogramming for efficient viral replication.

Lucidone suppresses dengue viral replication through the induction of heme oxygenase-1

Dengue virus (DENV) infection causes life-threatening diseases such as dengue hemorrhagic fever and dengue shock syndrome. Currently, there is no effective therapeutic agent or vaccine against DENV infection; hence, there is an urgent need to discover anti-DENV agents. The potential therapeutic efficacy of lucidone was first evaluated in vivo using a DENV-infected Institute of Cancer Research (ICR) suckling mouse model by monitoring body weight, clinical score, survival rate, and viral titer. We found that lucidone effectively protected mice from DENV infection by sustaining survival rate and reducing viral titers in DENV-infected ICR suckling mice. Then, the anti-DENV activity of lucidone was confirmed by western blotting and quantitative-reverse-transcription-polymerase chain reaction analysis, with an EC₅₀ value of 25 ± 3 μM. Lucidone significantly induced heme oxygenase-1 (HO-1) production against DENV replication by inhibiting DENV NS2B/3 protease activity to induce the DENV-suppressed antiviral interferon response. The inhibitory effect of lucidone on DENV replication was attenuated by silencing of HO-1 gene expression or blocking HO-1 activity. In addition, lucidone-stimulated nuclear factor erythroid 2-related factor 2 (Nrf2), which is involved in transactivation of HO-1 expression for its anti-DENV activity. Taken together, the mechanistic investigations revealed that lucidone exhibits significant anti-DENV activity in in vivo and in vitro by inducing Nrf2-mediated HO-1 expression, leading to blockage of viral protease activity to induce the anti-viral interferon (IFN) response. These results suggest that lucidone is a promising candidate for drug development.

SIRT6 Acts as a Negative Regulator in Dengue Virus-Induced Inflammatory Response by Targeting the DNA Binding Domain of NF-κB p65

Dengue virus (DENV) is a mosquito-borne single-stranded RNA virus causing human disease with variable severity. The production of massive inflammatory cytokines in dengue patients has been associated with dengue disease severity. However, the regulation of these inflammatory responses remains unclear. In this study, we report that SIRT6 is a negative regulator of innate immune responses during DENV infection. Silencing of Sirt6 enhances DENV-induced proinflammatory cytokine and chemokine production. Overexpression of SIRT6 inhibits RIG-I-like receptor (RLR) and Toll-like receptor 3 (TLR3) mediated NF-κB activation. The sirtuin core domain of SIRT6 is required for the inhibition of NF-κB p65 function. SIRT6 interacts with the DNA binding domain of p65 and competes with p65 to occupy the Il6 promoter during DENV infection. Collectively, our study demonstrates that SIRT6 negatively regulates DENV-induced inflammatory response via RLR and TLR3 signaling pathways.

Noninvasive Real-Time Characterization of Renal Clearance Kinetics in Diabetic Mice after Receiving Danshensu Treatment

Danshensu (DSS) is an active ingredient extracted from the root of the Danshen that could ameliorate oxidative stress via upregulation of heme oxygenase- (HO-) 1. Little is known about the treatment effects of DSS on kidney function in diabetic mice. Therefore, the primary aim of the present study was to characterize the renal clearance kinetics of IRdye800CW in db/db mice after DSS treatment. The secondary aim was to measure several biomarkers of renal function and oxidative stress (urinary F2-isoprostane, HO-1 in kidney and serum bilirubin). Fourteen db/db diabetic mice were randomly assigned into two groups and received either DSS treatment (DM + DSS) or vehicle treatment (DM). A third group that comprised of db/+ nondiabetic mice (non-DM control) received no DSS treatment and served as the nondiabetic control. At the end of a 3-week intervention period, serum and urinary biomarkers of renal function and oxidative stress were assessed and the renal clearance of IRdye800CW dye in all mice was determined noninvasively using Multispectral Optoacoustic Tomography. The major finding from this study suggested that DSS treatment in db/db mice improved renal clearance. Increased expression of HO-1 after DSS treatment also suggested that DSS might represent a potential therapeutic avenue for clinical intervention in diabetic nephropathy.

Meta-analysis of biomarkers for severe dengue infections

Background

Dengue viral infection is an acute infection that has the potential to have severe complications as its major sequela. Currently, there is no routine laboratory biomarker with which to predict the severity of dengue infection or monitor the effectiveness of standard management. Hence, this meta-analysis compared biomarker levels between dengue fever (DF) and severe dengue infections (SDI) to identify potential biomarkers for SDI.

Methods

Data concerning levels of cytokines, chemokines, and other potential biomarkers of DF, dengue hemorrhagic fever, dengue shock syndrome, and severe dengue were obtained for patients of all ages and populations using the Scopus, PubMed, and Ovid search engines. The keywords “(IL1* or IL-1*) AND (dengue*)” were used and the same process was repeated for other potential biomarkers, according to Medical Subject Headings terms suggested by PubMed and Ovid. Meta-analysis of the mean difference in plasma or serum level of biomarkers between DF and SDI patients was performed, separated by different periods of time (days) since fever onset. Subgroup analyses comparing biomarker levels of healthy plasma and sera controls, biomarker levels of primary and secondary infection samples were also performed, as well as analyses of different levels of severity and biomarker levels upon infection by different dengue serotypes.

Results

Fifty-six studies of 53 biomarkers from 3,739 dengue cases (2,021 DF and 1,728 SDI) were included in this meta-analysis. Results showed that RANTES, IL-7, IL-8, IL-10, IL-18, TGF-b, and VEGFR2 levels were significantly different between DF and SDI. IL-8, IL-10, and IL-18 levels increased during SDI (95% CI, 18.1–253.2 pg/mL, 3–13 studies, n = 177–1,909, I² = 98.86%–99.75%). In contrast, RANTES, IL-7, TGF-b, and VEGFR2 showed a decrease in levels during SDI (95% CI, −3238.7 to −3.2 pg/mL, 1–3 studies, n = 95–418, I² = 97.59%–99.99%). Levels of these biomarkers were also found to correlate with the severity of the dengue infection, in comparison to healthy controls. Furthermore, the results showed that IL-7, IL-8, IL-10, TGF-b, and VEGFR2 display peak differences between DF and SDI during or before the critical phase (day 4–5) of SDI.

Discussion

This meta-analysis suggests that IL-7, IL-8, IL-10, TGF-b, and VEGFR2 may be used as potential early laboratory biomarkers in the diagnosis of SDI. This can be used to predict the severity of dengue infection and to monitor the effectiveness of treatment. Nevertheless, methodological and reporting limitations must be overcome in future research to minimize variables that affect the results and to confirm the findings.

Immunomodulatory and antioxidant effects of total flavonoids of Spatholobus suberectus Dunn on PCV2 infected mice

Oxidative stress plays an important role in the pathogenesis of virus infection and antioxidants are becoming promising candidates as therapeutic agents. This study is designed to investigate the effect of total flavonoids of Spatholobus suberectus Dunn (TFSD) on oxidative stress in mice induced by porcine circovirus type 2 (PCV2) infection. The PCV2 infection leads to significant decrease in thymus and spleen indices, elevation of xanthine oxidase (XOD) and myeloperoxidase (MPO) activities, reduction in GSH level and GSH to GSSG ratio and decline of superoxide dismutase (SOD) activity, indicating the formation of immunosuppression and oxidative stress. TFSD treatment recovered the alteration of viscera index, antioxidant content and activities of oxidative-associated enzymes to a level similar to control. Our findings suggested that PCV2 induced immunosuppression and oxidative stress in mice and TFSD might be able to protect animals from virus infection via regulation of immune function and inhibition of oxidative stress.

IL-10 and socs3 Are Predictive Biomarkers of Dengue Hemorrhagic Fever

Background

Cytokines play important roles in the physiopathology of dengue infection; therefore, the suppressors of cytokine signaling (socs) that control the type and timing of cytokine functions could be involved in the origin of immune alterations in dengue.

Objective

To explore the association of cytokine and socs levels with disease severity in dengue patients.

Methods

Blood samples of 48 patients with confirmed dengue infection were analyzed. Amounts of interleukins IL-2, IL-4, IL-6, and IL-10, interferon- (IFN-) γ, and tumor necrosis factor- (TNF-) α were quantified by flow cytometry, and the relative expression of socs1 and socs3 mRNA was quantified by real-time RT-PCR.

Results

Increased levels of IL-10 and socs3 and lower expression of socs1 were found in patients with dengue hemorrhagic fever (DHF) with respect to those with dengue fever (DF) (p < 0.05). Negative correlations were found between socs1 and both IL-10 and socs3 (p < 0.01). The cutoff values of socs3 (>199.8-fold), socs1 (<1.94-fold), and IL-10 (>134 pg/ml) have the highest sensitivity and specificity to discriminate between DF and DHF.

Conclusion

Simultaneous changes in IL-10 and socs1/socs3 could be used as prognostic biomarkers of dengue severity.

Garlic Organosulfur Compounds Reduce Inflammation and Oxidative Stress during Dengue Virus Infection

Dengue virus (DENV) is a mosquito-borne flavivirus that causes significant global human disease and mortality. One approach to develop treatments for DENV infection and the prevention of severe disease is through investigation of natural medicines. Inflammation plays both beneficial and harmful roles during DENV infection. Studies have proposed that the oxidative stress response may be one mechanism responsible for triggering inflammation during DENV infection. Thus, blocking the oxidative stress response could reduce inflammation and the development of severe disease. Garlic has been shown to both reduce inflammation and affect the oxidative stress response. Here, we show that the garlic active compounds diallyl disulfide (DADS), diallyl sulfide (DAS) and alliin reduced inflammation during DENV infection and show that this reduction is due to the effects on the oxidative stress response. These results suggest that garlic could be used as an alternative treatment for DENV infection and for the prevention of severe disease development.

Effect of total flavonoids of Spatholobus suberectus Dunn on PCV2 induced oxidative stress in RAW264.7 cells

Background

This study was carried out to investigate the effect of total flavonoids of Spatholobus suberectus Dunn (TFSD) on PCV2 induced oxidative stress in RAW264.7 cells.

Methods

Oxidative stress model was established in RAW264.7 cells by infecting with PCV2. Virus infected cells were then treated with various concentrations (25 mg/ml, 50 mg/ml and 100 mg/ml) of TFSD. The levels of oxidative stress related molecules (NO, ROS, GSH and GSSG) and activities of associated enzymes (SOD, MPO and XOD were analyzed using ultraviolet spectrophotometry, fluorescence method and commercialized detection kits.

Results

PCV2 infection induced significant increase of NO secretion, ROS generation, GSSG content, activities of both XOD and MPO, and dramatically decrease of GSH content and SOD activity in RAW264.7 cells (P < 0.05). After treating with TFSD, PCV2 induced alteration of oxidative stress related molecule levels and enzyme activities were recovered to a level similar to control.

Conclusion

Our findings indicated that TFSD was able to regulate oxidative stress induced by PCV2 infection in RAW264.7 cells, which supports the ethnomedicinal use of this herb as an alternative or complementary therapeutic drug for reactive oxygen-associated pathologies.

Obesity is positively associated with arachidonic acid-derived 5- and 11-hydroxyeicosatetraenoic acid (HETE)

BACKGROUND

Oxylipids are oxygenated polyunsaturated fatty acid (PUFA) metabolites that are responsible for the onset and resolution of the inflammatory response. Enzymatic oxygenation through the lipoxygenase (LOX) or cytochrome P450 (CYP) pathways can form oxylipids that have either proinflammatory or proresolving functions depending on the type of PUFA substrate and degree of metabolism. The objective of this study was to determine how PUFA substrates and their corresponding oxylipids are associated with obesity.

METHODS

Plasma non-esterified FA and oxylipids were isolated from 123 Caucasian males using solid phase extraction and quantified using high performance liquid chromatography-tandem mass spectrometry. Statistical analyses included linear regressions and polytomous logistic regressions, and the responses were body mass index (BMI) and waist circumference (WC), and serum leptin, total adiponectin, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and C-peptide. Models were adjusted for age and smoking, and p-values were corrected for false discovery per Benjamini-Hochberg and Bonferroni.

RESULTS

We report that BMI, WC, and several serum cytokines were highly associated arachidonic acid (ARA)-derived hydroxyeicosatetraenoic acids (HETEs), and vicinal diols (i.e., alcohols on adjacent carbon atoms) derived from several PUFAs. There was a significant linear relationship between BMI, WC, and serum leptin, and ARA-derived 5-, 11-, and 15-HETE. Specifically, BMI and WC were positively associated with proinflammatory 5- and 11-hydroxyeicosatetraenoic acid (HETE), even after normalization to ARA concentrations and false discovery p-value correction. Individuals with 5-HETE concentrations >5.01nmol/L or 11-HETE concentrations and >0.89nmol/L were over 5 times more likely to be obese compared to those with ≤1.86nmol/L and ≤0.39nmol/L, respectively. Vicinal diols from linoleic, eicosapentaenoic, and docosahexaenoic acid were inversely associated with obesity. Across all statistical tests, vicinal diols were inversely associated with obesity whether normalized to parent PUFA concentrations or normalized to precursor epoxides. Interestingly, the proinflammatory cytokines IL-6 and TNF-α were not associated with any oxylipids. Since 5-HETE is a 5LOX product, 11-HETE is marker of lipid peroxidation, and vicinal diols are formed through soluble epoxide hydrolase (sEH) metabolism of CYP epoxygenated PUFAs, therefore, these results indicate that obesity is likely associated with altered metabolism with distinct oxygenating pathways. Taken together, our results indicate that obesity is associated with specific oxylipids indicative of altered PUFA metabolism through several pathways (i.e., LOX, reactive oxygen species, and sEH and CYP epoxygenase), rather than attributed solely to altered dietary PUFA intake.

Differential expression of NADPH oxidase-2 (Nox-2) and nuclear factor-erythroid 2-related factor 2 (Nrf2) transcripts in peripheral blood mononuclear cells isolated from dengue patients

The role of oxidative stress in the pathogenesis of dengue infection is not completely known. A recent study reveals the involvement of oxidative stress responsive molecules in the generation of host immune responses to dengue virus in vitro. Objective of the present study was to analyse the changes in the expression of oxidant-antioxidant genes Nox-2 (NADPH oxidase) and Nrf2 (nuclear factor-erythroid 2-related factor 2) in patients with dengue during the early phase of infection compared to other febrile illness (OFI) cases and healthy controls using Real-time qPCR assay. The study enrolled 88 dengue patients, 31 OFI cases, and 63 healthy individuals as controls. Out of 88 dengue cases, 32 were classified as severe dengue cases (SD) and remaining 56 patients as non-severe dengue (NSD). Blood samples were collected firstly at the time of admission and a second sampling was done from the available individuals (38 dengue and 13 OFI cases) at the time of defervescence. Total RNA was extracted from the Peripheral blood mononuclear cells and the transcripts level of Nox-2 and Nrf2 were analysed by qPCR. On DOA, both Nox-2 and Nrf2 expression was found to be down regulated in dengue and OFI cases (P < 0.05) compared to healthy controls. Interestingly at defervescence, the transcript levels were found to be significantly increased in dengue cases unlike OFI, where no such increment was evidenced. From DOA to DOD, the study observed a signficant increase in the levels of Nox-2 transcripts (P < 0.05) both in SD and NSD cases. But a significant Nrf2 activation was not observed in SD cases as we found in NSD cases. Thus  a steady and significant increase in Nox-2 transcript level in severe, non-severe and secondary dengue infected groups observed in the current study supports the earlier reports on the involvement of anti-oxidant response in dengue severity. However further studies on its protein levels and mechanistic action would decipher the exact role of these potential molecules in the disease virulence.

A Study on Gene Expression Profile of Endogenous Antioxidant Enzymes: CAT, MnSOD and GPx in Dengue Patients

Dengue is an arthropod-borne threat among tropical countries. Currently no effective means to treat the virus or to predict which patient will develop the severe form of the disease. Recently the relationship between oxidative/antioxidative response and dengue pathogenesis was suggested. Based on this the present study has analysed the expression of endogenous antioxidant genes: Catalase (CAT), Superoxide dismutase (MnSOD) and Glutathione peroxidase in patients with dengue compared to other febrile illness (OFI) and healthy controls. The study enrolled 88 dengue confirmed patients comprising 56 were patients with non-severe dengue, and 32 were severe dengue cases, 31 were patients with OFI, and 63 healthy controls were also involved. Peripheral blood mononuclear cells isolated from patients and controls during the day of admission and from the available cases on the day of defervescence were used to estimate the transcript levels by quantitative PCR. The expression levels of all the three genes were found to be down-regulated throughout the course of dengue infection (p < 0.05) and OFI cases compared to healthy controls. Within dengue group, no significant difference was observed in any of the parameters between severe and non-severe cases. Interestingly, a significant down-regulation of MnSOD expression was recorded in secondary dengue infection compared to primary during admission (p < 0.05). It was found that all the down-regulated study genes have positively correlated in all dengue cases during the day of admission (p < 0.01). But during defervescence, the same was found only between CAT and MnSOD. Down-regulated endogenous antioxidant enzymes during dengue infection could be the possible rationale of oxidative stress reported in dengue disease earlier. The present study markers could not distinguish dengue from OFI cases and severe from non-severe dengue cases. Mechanism of down-regulation has to be explored further which will pave the way for the therapeutic target in dengue disease.

Implications of oxidative stress on viral pathogenesis

Reactive species are frequently formed after viral infections. Antioxidant defences, including enzymatic and non-enzymatic components, protect against reactive species, but sometimes these defences are not completely adequate. An imbalance in the production of reactive species and the body's inability to detoxify these reactive species is referred to as oxidative stress. The aim of this review is to analyse the role of oxidative stress in the pathogenesis of viral infections and highlight some major therapeutic approaches that have gained importance, with regards to controlling virus-induced oxidative injury. Attention will be focused on DNA viruses (papillomaviruses, hepadnaviruses), RNA viruses (flaviviruses, orthomyxoviruses, paramyxoviruses, togaviruses) and retroviruses (human immunodeficiency virus). In general, viruses cause an imbalance in the cellular redox environment, which depending on the virus and the cell can result in different responses, e.g. cell signaling, antioxidant defences, reactive species, and other processes. Therefore, the modulation of reactive species production and oxidative stress potentially represents a novel pharmacological approach for reducing the consequences of viral pathogenesis.

Primary dengue virus infections induce differential cytokine production in Mexican patients

Severe dengue pathogenesis is not fully understood, but high levels of proinflammatory cytokines have been associated with dengue disease severity. In this study, the cytokine levels in 171 sera from Mexican patients with primary dengue fever (DF) and dengue haemorrhagic fever (DHF) from dengue virus (DENV) 1 (n = 116) or 2 (n = 55) were compared. DF and DHF were defined according to the patient’s clinical condition, the primary infections as indicated by IgG enzymatic immunoassay negative results, and the infecting serotype as assessed by real-time reverse transcription-polymerase chain reaction. Samples were analysed for circulating levels of interleukin (IL)-12p70, interferon (IFN)-γ, tumour necrosis factor (TNF)-α, IL-6, and IL-8 using a commercial cytometric bead array. Significantly higher IFN-γ levels were found in patients with DHF than those with DF. However, significantly higher IL-12p70, TNF-α, and IL-6 levels were associated with DHF only in patients who were infected with DENV2 but not with DENV1. Moreover, patients with DF who were infected with DENV1 showed higher levels of IL-12p70, TNF-α, and IL-6 than patients with DHF early after-fever onset. The IL-8 levels were similar in all cases regardless of the clinical condition or infection serotype. These results suggest that the association between high proinflammatory cytokine levels and dengue disease severity does not always stand, and it once again highlights the complex nature of DHF pathogenesis.