High generation of reactive oxygen species from neutrophils in patients with severe COVID-19

The Interplay of HIV and Long COVID in Sub-Saharan Africa: Mechanisms of Endothelial Dysfunction

PURPOSE OF REVIEW

Long COVID affects approximately 5 million people in Africa. This disease is characterized by persistent symptoms or new onset of symptoms after an acute SARS-CoV-2 infection. Specifically, the most common symptoms include a range of cardiovascular problems such as chest pain, orthostatic intolerance, tachycardia, syncope, and uncontrolled hypertension. Importantly, these conditions appear to have endothelial dysfunction as the common denominator, which is often due to impaired nitric oxide (NO) mechanisms. This review discusses the role of mechanisms contributing to endothelial dysfunction in Long COVID, particularly in people living with HIV.

RECENT FINDINGS

Recent studies have reported that increased inflammation and oxidative stress, frequently observed in Long COVID, may contribute to NO dysfunction, ultimately leading to decreased vascular reactivity. These mechanisms have also been reported in people living with HIV. In regions like Africa, where HIV infection is still a major public health challenge with a prevalence of approximately 26 million people in 2022. Specifically, endothelial dysfunction has been reported as a major mechanism that appears to contribute to cardiovascular diseases and the intersection with Long COVID mechanisms is of particular concern. Further, it is well established that this population is more likely to develop Long COVID following infection with SARS-CoV-2. Therefore, concomitant infection with SARS-CoV-2 may lead to accelerated cardiovascular disease. We outline the details of the worsening health problems caused by Long COVID, which exacerbate pre-existing conditions such as endothelial dysfunction. The overlapping mechanisms of HIV and SARS-CoV-2, particularly the prolonged inflammatory response and chronic hypoxia, may increase susceptibility to Long COVID. Addressing these overlapping health issues is critical as it provides clinical entry points for interventions that could improve and enhance outcomes and quality of life for those affected by both HIV and Long COVID in the region.

Role of Neutrophils in the Development of Steatotic Liver Disease

This review explores the biological aspects of neutrophils, their contributions to the development of steatotic liver disease, and their potential as therapeutic targets for the disease. Although alcohol-associated and metabolic dysfunction-associated liver diseases originate from distinct etiological factors, the two diseases frequently share excessive lipid accumulation as a common contributor to their pathogenesis, thereby classifying them as types of steatotic liver disease. Dysregulated lipid deposition in the liver induces hepatic injury, triggering the activation of the innate immunity, partially through neutrophil recruitment. Traditionally recognized for their role in microbial clearance, neutrophils have recently garnered attention for their involvement in sterile inflammation, a pivotal component of steatotic liver disease pathogenesis. In conclusion, technological innovations, including single-cell RNA sequencing, have gradually disclosed the existence of various neutrophil subsets; however, how the distinct subsets of neutrophil population contribute differentially to the development of steatotic liver disease remains unclear.

Increased Oxidative Stress and Decreased Citrulline in Blood Associated with Severe Novel Coronavirus Pneumonia in Adult Patients

This study investigated the correlation between oxidative stress and blood amino acids associated with nitric oxide metabolism in adult patients with coronavirus disease (COVID-19) pneumonia. Clinical data and serum samples were prospectively collected from 100 adult patients hospitalized for COVID-19 between July 2020 and August 2021. Patients with COVID-19 were categorized into three groups for analysis based on lung infiltrates, oxygen inhalation upon admission, and the initiation of oxygen therapy after admission. Blood data, oxidative stress-related biomarkers, and serum amino acid levels upon admission were compared in these groups. Patients with lung infiltrations requiring oxygen therapy upon admission or starting oxygen post-admission exhibited higher serum levels of hydroperoxides and lower levels of citrulline compared to the control group. No remarkable differences were observed in nitrite/nitrate, asymmetric dimethylarginine, and arginine levels. Serum citrulline levels correlated significantly with serum lactate dehydrogenase and C-reactive protein levels. A significant negative correlation was found between serum levels of citrulline and hydroperoxides. Levels of hydroperoxides decreased, and citrulline levels increased during the recovery period compared to admission. Patients with COVID-19 with extensive pneumonia or poor oxygenation showed increased oxidative stress and reduced citrulline levels in the blood compared to those with fewer pulmonary complications. These findings suggest that combined oxidative stress and abnormal citrulline metabolism may play a role in the pathogenesis of COVID-19 pneumonia.

Stable Nitroxide as Diagnostic Tools for Monitoring of Oxidative Stress and Hypoalbuminemia in the Context of COVID-19

Oxidative stress is a major source of ROS-mediated damage to macromolecules, tissues, and the whole body. It is an important marker in the severe picture of pathological conditions. The discovery of free radicals in biological systems gives a "start" to studying various pathological processes related to the development and progression of many diseases. From this moment on, the enrichment of knowledge about the participation of free radicals and free-radical processes in the pathogenesis of cardiovascular, neurodegenerative, and endocrine diseases, inflammatory conditions, and infections, including COVID-19, is increasing exponentially. Excessive inflammatory responses and abnormal reactive oxygen species (ROS) levels may disrupt mitochondrial dynamics, increasing the risk of cell damage. In addition, low serum albumin levels and changes in the normal physiological balance between reduced and oxidized albumin can be a serious prerequisite for impaired antioxidant capacity of the body, worsening the condition in patients. This review presents the interrelationship between oxidative stress, inflammation, and low albumin levels, which are hallmarks of COVID-19.

Dihydrophenanthropyrans derived from the pseudobulbs of Pholidota chinensis alleviates neutrophilic inflammation by inhibiting MAPKs and calcium

Five dihydrophenanthropyrans (1-5) were isolated from the pseudobulbs of Pholidota chinensis, among which 1,3-di(4'-hydroxybenzy)-imbricatin (3) was isolated from the nature for the first time. Their structures were elucidated and established through various spectroscopic methods. These compounds exhibited a potent inhibition effect on both N-formyl-methionyl-leucyl-phenylalanine (fMLF)-induced superoxide anion generation and elastase release with IC50 values ranging from 0.23 to 7.63 μM. Furthermore, dihydrophenanthropyrans (1-3) also demonstrated a dose-dependent reactive oxygen species (ROS) scavenging effect. In addition, dihydrophenanthropyrans (2-3) exhibited a dose-dependent reduction in the intracellular Ca2+ concentration ([Ca2+]i) in fMLF-activated human neutrophils. Moreover, dihydrophenanthropyrans (1-3) selectively inhibited the phosphorylation of c-Jun N-terminal kinases (JNKs) and p38, while only dihydrophenanthropyran (1) inhibited the phosphorylation of extracellular signal-regulated kinases (ERKs) in fMLF-activated human neutrophils. Notably, dihydrophenanthropyrans (1-3) did not affect protein kinase B (AKT) activity in these cells. These findings highlight the potent anti-inflammatory capabilities of dihydrophenanthropyrans, manifested through their ability to inhibit superoxide anion generation, suppress elastase release, and selectively modulate key signaling pathways in human neutrophils. This suggests that dihydrophenanthropyrans hold significant promise as therapeutic agents for conditions associated with neutrophil-mediated inflammation.

ISKNV Triggers AMPK/mTOR-Mediated Autophagy Signaling through Oxidative Stress, Inducing Antioxidant Enzyme Expression and Enhancing Viral Replication in GF-1 Cells

Infectious spleen and kidney necrosis virus (ISKNV) infections can induce the process of host cellular autophagy but have rarely been identified within the molecular autophagy signaling pathway. In the present study, we demonstrated that ISKNV induces ROS-mediated oxidative stress signals for the induction of 5'AMP-activated protein kinase/mechanistic target of rapamycin kinase (AMPK/mTOR)-mediated autophagy and upregulation of host antioxidant enzymes in fish GF-1 cells. We also examined ISKNV-induced oxidative stress, finding that reactive oxidative species (ROS) increased by 1.5-fold and 2.5-fold from day 2 to day 3, respectively, as assessed by the H2DCFDA assay for tracing hydrogen peroxide (H2O2), which was blocked by NAC treatment in fish GF-1 cells. Furthermore, ISKNV infection was shown to trigger oxidative stress/Nrf2 signaling from day 1 to day 3; this event was then correlated with the upregulation of antioxidant enzymes such as Cu/ZnSOD and MnSOD and was blocked by the antioxidant NAC. Using an MDC assay, TEM analysis and autophagy marker LC3-II/I ratio, we found that ROS stress can regulate autophagosome formation within the induction of autophagy, which was inhibited by NAC treatment in GF-1 cells. Through signal analysis, we found that AMPK/mTOR flux was modulated through inhibition of mTOR and activation of AMPK, indicating phosphorylation levels of mTOR Ser 2448 and AMPK Thr 172 from day 1 to day 3; however, this process was reversed by NAC treatment, which also caused a reduction in virus titer (TCID50%) of up to 1000 times by day 3 in GF-1 cells. Thus, ISKNV-induced oxidative stress signaling is blocked by antioxidant NAC, which can also either suppress mTOR/AMPK autophagic signals or reduce viral replication. These findings may provide the basis for the creation of DNA control and treatment strategies.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: the biology of a neglected disease

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic, debilitating disease characterised by a wide range of symptoms that severely impact all aspects of life. Despite its significant prevalence, ME/CFS remains one of the most understudied and misunderstood conditions in modern medicine. ME/CFS lacks standardised diagnostic criteria owing to variations in both inclusion and exclusion criteria across different diagnostic guidelines, and furthermore, there are currently no effective treatments available. Moving beyond the traditional fragmented perspectives that have limited our understanding and management of the disease, our analysis of current information on ME/CFS represents a significant paradigm shift by synthesising the disease's multifactorial origins into a cohesive model. We discuss how ME/CFS emerges from an intricate web of genetic vulnerabilities and environmental triggers, notably viral infections, leading to a complex series of pathological responses including immune dysregulation, chronic inflammation, gut dysbiosis, and metabolic disturbances. This comprehensive model not only advances our understanding of ME/CFS's pathophysiology but also opens new avenues for research and potential therapeutic strategies. By integrating these disparate elements, our work emphasises the necessity of a holistic approach to diagnosing, researching, and treating ME/CFS, urging the scientific community to reconsider the disease's complexity and the multifaceted approach required for its study and management.

Endothelial ERG programs neutrophil transcriptome for sustained anti-inflammatory vascular niche

Neutrophils (PMNs) reside as a marginated pool within the vasculature, ready for deployment during infection. However, how endothelial cells (ECs) control PMN extravasation and activation to strengthen tissue homeostasis remains ill-defined. Here, we found that the vascular ETS-related gene (ERG) is a generalized mechanism regulating PMN activity in preclinical tissue injury models and human patients. We show that ERG loss in ECs rewired PMN-transcriptome, enriched for genes associated with the CXCR2-CXCR4 signaling. Rewired PMNs compromise mice survival after pneumonia and induced lung vascular inflammatory injury following adoptive transfer into naïve mice, indicating their longevity and inflammatory activity memory. Mechanistically, EC-ERG restricted PMN extravasation and activation by upregulating the deubiquitinase A20 and downregulating the NFκB-IL8 cascade. Rescuing A20 in EC-Erg -/- endothelium or suppressing PMN-CXCR2 signaling rescued EC control of PMN activation. Findings deepen our understanding of EC control of PMN-mediated inflammation, offering potential avenues for targeting various inflammatory diseases.

Highlights

ERG regulates trans-endothelial neutrophil (PMN) extravasation, retention, and activationLoss of endothelial (EC) ERG rewires PMN-transcriptomeAdopted transfer of rewired PMNs causes inflammation in a naïve mouse ERG transcribes A20 and suppresses CXCR2 function to inactivate PMNs.

In brief/blurb

The authors investigated how vascular endothelial cells (EC) control polymorphonuclear neutrophil (PMN) extravasation, retention, and activation to strengthen tissue homeostasis. They showed that EC-ERG controls PMN transcriptome into an anti-adhesive and anti-inflammatory lineage by synthesizing A20 and suppressing PMNs-CXCR2 signaling, defining EC-ERG as a target for preventing neutrophilic inflammatory injury.

Neutrophils and Anesthetic Drugs: Implications in Onco-Anesthesia

Apart from being a significant line of defense in the host defense system, neutrophils have many immunological functions. Although there are not many publications that accurately present the functions of neutrophils in relation to oncological pathology, their activity and implications have been studied a lot recently. This review aims to extensively describe neutrophils functions'; their clinical implications, especially in tumor pathology; the value of clinical markers related to neutrophils; and the implications of neutrophils in onco-anesthesia. This review also aims to describe current evidence on the influence of anesthetic drugs on neutrophils' functions and their potential influence on perioperative outcomes.

Do chemokine/chemokine receptor axes play paramount parts in trafficking and oriented locomotion of monocytes/macrophages toward the lungs of COVID-19 infected patients? A systematic review

The COVID-19 (coronavirus disease 2019) is a well-defined viral infection, resulting from SARS-CoV-2 (severe acute respiratory syndrome- coronavirus-2). The innate immune system serves as the first line of defense to limit viral spreading and subsequently stimulate adaptive immune responses by the prominent aids of its cellular and molecular arms. Monocytes are defined as the most prominent innate immune cells (IICs) that are reactive against invading pathogens. These cells support host protection against the virus that is mediated by several non-specific mechanisms such as phagocytosis, producing antiviral enzymes, and recruitment of immune cells toward and into the infected tissues. They have the ability to egress from blood and migrate to the SARS-CoV-2 infected regions by the aid of some defense-related functions like chemotaxis, which is mediated by chemical compounds, e.g., chemokines. Chemokines, in addition to their related ligands are categorized within the most important and deserved agents involved in oriented trafficking of monocytes/macrophages towards and within the lung parenchyma in both steady state and pathological circumstances, including COVID-19-raised infection. However, the overexpression of chemokines could have deleterious effects on various organs through the induction of cytokine storm and may be the most important leading mechanisms in the pathogenesis of COVID-19. Authors have aimed the current review article to describe present knowledge about the interplay between monocytes/macrophages and SARS-CoV-2 with a focus on the ability of IICs to migrate and home into the lung of COVID-19 patients through various chemokine-chemokine receptor axes to promote our understanding regarding this disease.

High neutrophil-to-lymphocyte ratio is associated with cancer therapy-related cardiovascular toxicity in high-risk cancer patients under immune checkpoint inhibitor therapy

BACKGROUND

Cancer therapy-related cardiovascular toxicity (CTR-CVT) from immune checkpoint inhibitor (ICI) therapy is still incompletely characterized, and patients with pre-existing cardiovascular disease represent a particularly high-risk cohort. Valid parameters for risk stratification of these patients are missing. Neutrophil-to-lymphocyte ratio (NLR) has been shown to predict mortality and adverse events in other cardiovascular cohorts. The present study aims to examine the predictive capacity of NLR for risk stratification of patients particularly vulnerable for CTR-CVT under ICI therapy.

METHODS

We performed an analysis of 88 cancer patients (69 ± 11 years, 25% female) with pre-existing cardiovascular disease under ICI therapy from the prospective Essen Cardio-Oncology Registry (ECoR). NLR was assessed at patient enrollment and the population was divided through receiver operator characteristic (ROC) curve analysis in patients with low (< 4.57) and high (≥ 4.57) NLR. Endpoint was the whole spectrum of CTR-CVT, according to the European guidelines on cardio-oncology. The median follow-up was 357 days (interquartile range (IQR): 150-509 days).

RESULTS

We observed 4 cases of myocarditis, 17 cases of vascular toxicity, 3 cases of arterial hypertension, 22 cases of arrhythmia or QTc prolongation and 17 cases of cardiovascular dysfunction. NLR was associated with overall CTR-CVT by univariable Cox regression (hazard ratio (HR): 1.443; 95% confidence interval (CI) 1.082-1.925; p = 0.013). However, this association was attenuated after adjusting for further confounders.

CONCLUSION

NLR is moderately associated with CTR-CVT in cancer patients with pre-existing cardiovascular disease under ICI therapy. Surveillance of NLR during ICI therapy might be an effective and economically biomarker for risk stratification in these high-risk patients.

Neutrophils in Physiology and Pathology

Infections, cardiovascular disease, and cancer are major causes of disease and death worldwide. Neutrophils are inescapably associated with each of these health concerns, by either protecting from, instigating, or aggravating their impact on the host. However, each of these disorders has a very different etiology, and understanding how neutrophils contribute to each of them requires understanding the intricacies of this immune cell type, including their immune and nonimmune contributions to physiology and pathology. Here, we review some of these intricacies, from basic concepts in neutrophil biology, such as their production and acquisition of functional diversity, to the variety of mechanisms by which they contribute to preventing or aggravating infections, cardiovascular events, and cancer. We also review poorly explored aspects of how neutrophils promote health by favoring tissue repair and discuss how discoveries about their basic biology inform the development of new therapeutic strategies.

Diverse bacteria elicit distinct neutrophil responses in a physiologically relevant model of infection

An efficient neutrophil response is critical for fighting bacterial infections, which remain a significant global health concern; therefore, modulating neutrophil function could be an effective therapeutic approach. While we have a general understanding of how neutrophils respond to bacteria, how neutrophil function differs in response to diverse bacterial infections remains unclear. Here, we use a microfluidic infection-on-a-chip device to investigate the neutrophil response to four bacterial species: Pseudomonas aeruginosa, Salmonella enterica, Listeria monocytogenes, and Staphylococcus aureus. We find enhanced neutrophil extravasation to L. monocytogenes, a limited overall response to S. aureus, and identify IL-6 as universally important for neutrophil extravasation. Furthermore, we demonstrate a higher percentage of neutrophils generate reactive oxygen species (ROS) when combating gram-negative bacteria versus gram-positive bacteria. For all bacterial species, we found the percentage of neutrophils producing ROS increased following extravasation through an endothelium, underscoring the importance of studying neutrophil function in physiologically relevant models.

The Functional Roles of MDSCs in Severe COVID-19 Pathogenesis

Severe COVID-19 is a major cause of morbidity and mortality worldwide, especially among those with co-morbidities, the elderly, and the immunocompromised. However, the molecular determinants critical for severe COVID-19 progression remain to be fully elucidated. Meta-analyses of transcriptomic RNAseq and single-cell sequencing datasets comparing severe and mild COVID-19 patients have demonstrated that the early expansion of myeloid-derived suppressor cells (MDSCs) could be a key feature of severe COVID-19 progression. Besides serving as potential early prognostic biomarkers for severe COVID-19 progression, several studies have also indicated the functional roles of MDSCs in severe COVID-19 pathogenesis and possibly even long COVID. Given the potential links between MDSCs and severe COVID-19, we examine the existing literature summarizing the characteristics of MDSCs, provide evidence of MDSCs in facilitating severe COVID-19 pathogenesis, and discuss the potential therapeutic avenues that can be explored to reduce the risk and burden of severe COVID-19. We also provide a web app where users can visualize the temporal changes in specific genes or MDSC-related gene sets during severe COVID-19 progression and disease resolution, based on our previous study.

[Pathogenetic approaches to the correction of vascular homeostasis in patients with COVID-19: A review]

The adverse outcomes in patients with COVID-19 in the initial phase of the disease are often due to the development of cytokine storm, endothelial dysfunction, shifts in the hemostasis system, microangiopathy, angiocentric inflammation, and pathological angiogenesis, which require targeted therapy. Unfortunately, to date, there is still no drug with proven high efficacy. This review is to analyse the literature data on the pathogenesis of vascular homeostasis lesions and possible ways to correct the existing shifts in patients with COVID-19. When the oxygen content in the tissue decreases, one of the most important mechanisms of adaptation is the activation of the succinate oxidase pathway, but under conditions of prolonged hypoxia and intoxication, the succinate reserve is rapidly depleted. That is why exogenous of succinic acid can enhance the adaptive capabilities of the organism and improve the prognosis in patients with COVID-19. Succinic acid preparations contribute to normalization of energy exchange and reduction of oxidative stress, especially in combination with inosine, nicotinamide and riboflavin and are widely used in clinical practice in various nosological forms. Taking into account the analysis of data on the mechanisms of clinical effects of succinate-containing preparations, this group of drugs can be considered as promising with regard to the correction of vascular disorders in COVID-19.

Evaluation of oxidative stress level: reactive oxygen species, reduced glutathione, and D-dimer in patients hospitalized due to COVID-19

Elevated D-dimer levels at hospital admission may also indicate a higher likelihood of progressing to a severe or critical state. This study aimed to assess reactive oxygen species (ROS), non-enzymatic antioxidant reduced glutathione (GSH), and D-dimer levels in COVID-19 patients upon admission, examining their association with mortality outcomes. Data was collected from the medical records of 170 patients hospitalized in a referral hospital unit between March 2020 and December 2021. Patients were divided into two groups: the ward bed group (n = 87), comprising 51% with moderate clinical conditions, and the intensive care unit (ICU) group (n = 83), comprising 49% with severe conditions. The mean age was 59.4 years, with a male predominance of 52.4%. The overall death rate was 43%, with 30.6% in the moderate group and 69.4% in the severe group. The average time from symptom onset to hospitalization was 6.42 days. Results showed that non-survivors had high D-dimer and ROS counts, longer ICU stays, and worse saturation levels at admission. In conclusion, elevated ROS and D-dimer levels may contribute to worse outcomes in critically ill patients, potentially serving as specific and sensitive predictors of poor outcomes upon admission.

Eco-evolutionary dynamics of experimental Pseudomonas aeruginosa populations under oxidative stress

Within-host environments are likely to present a challenging and stressful environment for opportunistic pathogenic bacteria colonizing from the external environment. How populations of pathogenic bacteria respond to such environmental challenges and how this varies between strains is not well understood. Oxidative stress is one of the defences adopted by the human immune system to confront invading bacteria. In this study, we show that strains of the opportunistic pathogenic bacterium Pseudomonas aeruginosa vary in their eco-evolutionary responses to hydrogen peroxide stress. By quantifying their 24 h growth kinetics across hydrogen peroxide gradients we show that a transmissible epidemic strain isolated from a chronic airway infection of a cystic fibrosis patient, LESB58, is much more susceptible to hydrogen peroxide than either of the reference strains, PA14 or PAO1, with PAO1 showing the lowest susceptibility. Using a 12 day serial passaging experiment combined with a mathematical model, we then show that short-term susceptibility controls the longer-term survival of populations exposed to subinhibitory levels of hydrogen peroxide, but that phenotypic evolutionary responses can delay population extinction. Our model further suggests that hydrogen peroxide driven extinctions are more likely with higher rates of population turnover. Together, these findings suggest that hydrogen peroxide is likely to be an effective defence in host niches where there is high population turnover, which may explain the counter-intuitively high susceptibility of a strain isolated from chronic lung infection, where such ecological dynamics may be slower.

Assessing neutrophil-derived ROS production at the bedside: a potential prognostic tool in severe COVID-19 cases

PURPOSE

A prompt and effective immune response is required for clearance of pathogens but exaggerated states of inflammation can cause extensive collateral damage to the host. We have previously used a rapid near-patient assay that measures the functional capacity of neutrophils to produce reactive oxygen species (ROS) to show that values are elevated in patients with severe COVID-19 or sepsis. Here, we assess the utility of longitudinal ROS measurements to monitor and predict mortality outcome for patients with COVID-19 infection being treated in an ICU setting.

METHODS

We used the Leukocyte ImmunoTest™ (LIT™) to quantify neutrophil ROS release using a small volume (10 µL) of capillary blood in a portable, rapid (10-min) format.

RESULTS

ROS values (LIT score) and ROS levels assessed in relation to neutrophil count (LIT/N) were both markedly elevated in the patient group. Furthermore, these correlated strongly with peripheral neutrophil count and CRP value. Serial measurement of neutrophil or CRP values were not able to reliably predict mortality within the study. In contrast, LIT and LIT/N values started to decline at 7 and 5 days, respectively, in patients who survived ICU admission and this increment increased further thereafter.

CONCLUSIONS

This study raises the possibility of LIT and LIT/N to be used as a predictive clinical tool for patients with severe COVID-19 and argues for its assessment to inform on prognosis, and potentially guide treatment pathways, in other disorders associated with neutrophil activation.

TAKE-HOME MESSAGE

A longitudinal study of 44 severe COVID-19 patients in the ICU of a leading teaching hospital has demonstrated the prognostic potential of a rapid bedside assay of neutrophil-derived reactive oxygen species (ROS). Assessment of changes in ROS production, as measured using the Leukocyte ImmunoTest™, shows that ROS production generally declined back to normal levels for patients who survived, but remained elevated for those patients who did not survive.

Effects of Sulforaphane on SARS‑CoV‑2 infection and NF‑κB dependent expression of genes involved in the COVID‑19 'cytokine storm'

Since its spread at the beginning of 2020, the coronavirus disease 2019 (COVID‑19) pandemic represents one of the major health problems. Despite the approval, testing, and worldwide distribution of anti‑severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) vaccines, the development of specific antiviral agents targeting the SARS‑CoV‑2 life cycle with high efficiency, and/or interfering with the associated 'cytokine storm', is highly required. A recent study, conducted by the authors' group indicated that sulforaphane (SFN) inhibits the expression of IL‑6 and IL‑8 genes induced by the treatment of IB3‑1 bronchial cells with a recombinant spike protein of SARS‑CoV‑2. In the present study, the ability of SFN to inhibit SARS‑CoV‑2 replication and the expression of pro‑inflammatory genes encoding proteins of the COVID‑19 'cytokine storm' was evaluated. SARS‑CoV‑2 replication was assessed in bronchial epithelial Calu‑3 cells. Moreover, SARS‑CoV‑2 replication and expression of pro‑inflammatory genes was evaluated by reverse transcription quantitative droplet digital PCR. The effects on the expression levels of NF‑κB were assessed by western blotting. Molecular dynamics simulations of NF‑kB/SFN interactions were conducted with Gromacs 2021.1 software under the Martini 2 CG force field. Computational studies indicated that i) SFN was stably bound with the NF‑κB monomer; ii) a ternary NF‑kB/SFN/DNA complex was formed; iii) the SFN interacted with both the protein and the nucleic acid molecules modifying the binding mode of the latter, and impairing the full interaction between the NF‑κB protein and the DNA molecule. This finally stabilized the inactive complex. Molecular studies demonstrated that SFN i) inhibits the SARS‑CoV‑2 replication in infected Calu‑3 cells, decreasing the production of the N‑protein coding RNA sequences, ii) decreased NF‑κB content in SARS‑CoV‑2 infected cells and inhibited the expression of NF‑kB‑dependent IL‑1β and IL‑8 gene expression. The data obtained in the present study demonstrated inhibitory effects of SFN on the SARS‑CoV‑2 life cycle and on the expression levels of the pro‑inflammatory genes, sustaining the possible use of SFN in the management of patients with COVID‑19.

Neutrophils in COVID-19: recent insights and advances

Coronavirus disease 2019 (COVID-19) is an acute respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which can lead to acute respiratory distress syndrome (ARDS), multi-organ failure and death, posing significant threat to human health. Studies have found that pathological mechanisms, such as cytokine storms caused by uncontrolled innate immune system activation, release of damage-associated molecular patterns during tissue injury and a high incidence of thrombotic events, are associated with the function and dysfunction of neutrophils. Specifically, the increased formation of low-density neutrophils (LDNs) and neutrophil extracellular traps (NETs) has been shown to be closely linked with the severity and poor prognosis in patients with COVID-19. Our work focuses on understanding the increased number, abnormal activation, lung tissue infiltration, and elevated neutrophil-to-lymphocyte ratio in the pathogenesis of COVID-19. We also explore the involvement of NETs and LDNs in disease progression and thrombosis formation, along with potential therapeutic strategies targeting neutrophil and NETs formation.

Association between laboratory markers and Covid-19 disease severity and outcome: a retrospective cohort study in Saudi Arabia

Introduction

In Saudi Arabia, limited studies have evaluated factors including epidemiologic, clinical, and laboratory findings that are associated with COVID-19 disease. The aim of this paper was to identify laboratory parameters used in King Abdulaziz University Hospital which show an association with disease severity and patient outcome in the form of mortality.

Methods

Age, gender, medical history, and laboratory parameters were all retrospectively assessed concerning disease severity and disease outcome in a total of 111 COVID-19 patients at King Abdulaziz University Hospital between July 2020 and August 2020. Patients were categorized into mild disease if they did not require ward admission, moderate if they met the Ministry of Health criteria for isolation ward admition, and severe if they were admitted to the ICU.

Results

Age but not gender was associated with the disease severity X² (4, N = 110) = 27.2, p <0.001. Of all laboratory parameters on admission, only the levels of Albumin appeared to be significantly associated X² (2, N =70) = 6.6, p <0.05 with disease severity. Age but not gender was also significantly associated with disease outcome X² (2, N = 110) = 12.8, p < 0.01. Interestingly, RBC count also showed a significant relation with disease outcome X² (2, N = 71) = 6.1, p <0.05.

Discussion

This study provides more understanding of the laboratory characteristics in our part of the world to efficiently manage the disease.

Ketogenic Diet and Ketone Bodies as Clinical Support for the Treatment of SARS-CoV-2-Review of the Evidence

One of the proposed nutritional therapies to support drug therapy in COVID-19 is the use of a ketogenic diet (KD) or ketone bodies. In this review, we summarized the evidence from tissue, animal, and human models and looked at the mechanisms of action of KD/ketone bodies against COVID-19. KD/ketone bodies were shown to be effective at the stage of virus entry into the host cell. The use of β-hydroxybutyrate (BHB), by preventing the metabolic reprogramming associated with COVID-19 infection and improving mitochondrial function, reduced glycolysis in CD4+ lymphocytes and improved respiratory chain function, and could provide an alternative carbon source for oxidative phosphorylation (OXPHOS). Through multiple mechanisms, the use of KD/ketone bodies supported the host immune response. In animal models, KD resulted in protection against weight loss and hypoxemia, faster recovery, reduced lung injury, and resulted in better survival of young mice. In humans, KD increased survival, reduced the need for hospitalization for COVID-19, and showed a protective role against metabolic abnormalities after COVID-19. It appears that the use of KD and ketone bodies may be considered as a clinical nutritional intervention to assist in the treatment of COVID-19, despite the fact that numerous studies indicate that SARS-CoV-2 infection alone may induce ketoacidosis. However, the use of such an intervention requires strong scientific validation.

Mycobacterium tuberculosis and SARS-CoV-2 co-infections: The knowns and unknowns

Health impacts of Mycobacterium tuberculosis (Mtb) and SARS-CoV-2 co-infections are not fully understood. Both pathogens modulate host responses and induce immunopathology with extensive lung damage. With a quarter of the world's population harboring latent TB, exploring the relationship between SARS-CoV-2 infection and its effect on the transition of Mtb from latent to active form is paramount to control this pathogen. The effects of active Mtb infection on establishment and severity of COVID-19 are also unknown, despite the ability of TB to orchestrate profound long-lasting immunopathologies in the lungs. Absence of mechanistic studies and co-infection models hinder the development of effective interventions to reduce the health impacts of SARS-CoV-2 and Mtb co-infection. Here, we highlight dysregulated immune responses induced by SARS-CoV-2 and Mtb, their potential interplay, and implications for co-infection in the lungs. As both pathogens master immunomodulation, we discuss relevant converging and diverging immune-related pathways underlying SARS-CoV-2 and Mtb co-infections.

The Impact of Serum Levels of Reactive Oxygen and Nitrogen Species on the Disease Severity of COVID-19

Elucidation of the redox pathways in severe coronavirus disease 2019 (COVID-19) might aid in the treatment and management of the disease. However, the roles of individual reactive oxygen species (ROS) and individual reactive nitrogen species (RNS) in COVID-19 severity have not been studied to date. The main objective of this research was to assess the levels of individual ROS and RNS in the sera of COVID-19 patients. The roles of individual ROS and RNS in COVID-19 severity and their usefulness as potential disease severity biomarkers were also clarified for the first time. The current case-control study enrolled 110 COVID-19-positive patients and 50 healthy controls of both genders. The serum levels of three individual RNS (nitric oxide (NO^•), nitrogen dioxide (ONO^-), and peroxynitrite (ONOO^-)) and four ROS (superoxide anion (O₂^•-), hydroxyl radical (^•OH), singlet oxygen (¹O₂), and hydrogen peroxide (H₂O₂)) were measured. All subjects underwent thorough clinical and routine laboratory evaluations. The main biochemical markers for disease severity were measured and correlated with the ROS and RNS levels, and they included tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), the neutrophil-to-lymphocyte ratio (NLR), and angiotensin-converting enzyme 2 (ACE2). The results indicated that the serum levels of individual ROS and RNS were significantly higher in COVID-19 patients than in healthy subjects. The correlations between the serum levels of ROS and RNS and the biochemical markers ranged from moderate to very strongly positive. Moreover, significantly elevated serum levels of ROS and RNS were observed in intensive care unit (ICU) patients compared with non-ICU patients. Thus, ROS and RNS concentrations in serum can be used as biomarkers to track the prognosis of COVID-19. This investigation demonstrated that oxidative and nitrative stress play a role in the etiology of COVID-19 and contribute to disease severity; thus, ROS and RNS are probable innovative targets in COVID-19 therapeutics.

Effect of COVID-19 on sperm parameters: pathologic alterations and underlying mechanisms

The rapid outbreak of the coronavirus disease 2019 (COVID-19) pandemic has brought challenges to different medical fields, especially reproductive health. To date, most studies on the effects of COVID-19 on male reproduction have some limitations. In addition, there is little research on the mechanisms underlying by which severe acute respiratory syndrome coronavirus 2 infection affects semen quality. Here, we revealed the possible impact of COVID-19 on sperm parameters and the potential mechanisms. At present, it is still controversial whether COVID-19-induced fever adversely affects sperm parameters. Severe acute respiratory syndrome coronavirus 2 can induce up-regulation of pro-inflammatory cytokine, which leads to the destruction of blood-testis barrier and impairment of spermatogenesis. Moreover, severe viral infection of the respiratory system could induce systemic oxidative stress. Sperm are highly vulnerable to it due to their limited levels of antioxidant defense, unsophisticated DNA damage detection and repair mechanisms. Our review prompt medical staff and patients to consciously check the reproductive function of COVID-19 male patients. Moreover, opening our prospective beyond the direct infection could be the key to better understand the COVID-19 short and long-term effects and provide a new idea for future treatment of patients with reproductive function injury.

Reduced IL-8 Secretion by NOD-like and Toll-like Receptors in Blood Cells from COVID-19 Patients

Severe inflammatory responses are associated with the misbalance of innate and adaptive immunity. TLRs, NLRs, and cytokine receptors play an important role in pathogen sensing and intracellular control, which remains unclear in COVID-19. This study aimed to evaluate IL-8 production in blood cells from COVID-19 patients in a two-week follow-up evaluation. Blood samples were taken at admission (t1) and after 14 days of hospitalization (t2). The functionality of TLR2, TLR4, TLR7/8, TLR9, NOD1, and NOD2 innate receptors and IL-12 and IFN-γ cytokine receptors was evaluated by whole blood stimulation with specific synthetic receptor agonists through the quantification of IL-8, TNF-α, or IFN-γ. At admission, ligand-dependent IL-8 secretion was 6.4, 13, and 2.5 times lower for TLR2, TLR4, and endosomal TLR7/8 receptors, respectively, in patients than in healthy controls. Additionally, IL-12 receptor-induced IFN-γ secretion was lower in COVID-19 patients than in healthy subjects. We evaluated the same parameters after 14 days and observed significantly higher responses for TLR2, TLR4, TLR7/8, TLR9, and NOD1, NOD2, and IFN-γ receptors. In conclusion, the low secretion of IL-8 through stimulation with agonists of TLR2, TLR4, TLR7/8, TLR9, and NOD2 at t1 suggests their possible contribution to immunosuppression following hyperinflammation in COVID-19 disease.

Cellular and molecular features of COVID-19 associated ARDS: therapeutic relevance

The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection can be asymptomatic or cause a disease (COVID-19) characterized by different levels of severity. The main cause of severe COVID-19 and death is represented by acute (or acute on chronic) respiratory failure and acute respiratory distress syndrome (ARDS), often requiring hospital admission and ventilator support.The molecular pathogenesis of COVID-19-related ARDS (by now termed c-ARDS) is still poorly understood. In this review we will discuss the genetic susceptibility to COVID-19, the pathogenesis and the local and systemic biomarkers correlated with c-ARDS and the therapeutic options that target the cell signalling pathways of c-ARDS.

Links between Vitamin K, Ferroptosis and SARS-CoV-2 Infection

Ferroptosis is a recently discovered form of programmed cell death. It is characterized by the accumulation of iron and lipid hydroperoxides in cells. Vitamin K is known to have antioxidant properties and plays a role in reducing oxidative stress, particularly in lipid cell membranes. Vitamin K reduces the level of reactive oxygen species by modulating the expression of antioxidant enzymes. Additionally, vitamin K decreases inflammation and potentially prevents ferroptosis. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leading to coronavirus disease 2019 (COVID-19) is associated with oxidant–antioxidant imbalance. Studies have shown that intensified ferroptosis occurs in various tissues and cells affected by COVID-19. Vitamin K supplementation during SARS-CoV-2 infection may have a positive effect on reducing the severity of the disease. Preliminary research suggests that vitamin K may reduce lipid peroxidation and inhibit ferroptosis, potentially contributing to its therapeutic effects in COVID-19 patients. The links between ferroptosis, vitamin K, and SARS-CoV-2 infection require further investigation, particularly in the context of developing potential treatment strategies for COVID-19.

Antioxidant and Antithrombotic Activities of Kenaf Seed (Hibiscus cannabinus) Coat Ethanol Extract in Sprague Dawley Rats

Oxidative stress has been implicated in deadly lifestyle diseases, and antioxidants from plant sources are the primary option in the treatment regime. Kenaf seeds are the storehouse of potential natural antioxidant phytoconstituents. Perhaps, none of the studies documented the phytoconstituents and their antioxidant potential from Kenaf seed coat so far. Thus, the current study focuses on exploring the protective effect of Kenaf Seed Coat Ethanol Extract (KSCEE) against sodium nitrite and diclofenac-induced oxidative stress in vitro (red blood cell and platelets model) and in vivo (female Sprague Dawely rat's model) along with the antithrombotic activity. The infrared spectrophotometry data showed the heterogeneous functional groups (CH, OH, C = C, C = C-C) and aromatic rings. Reverse phase high-performance liquid chromatography and gas chromatography-mass spectrometry chromatogram of KSCEE also evidenced the presence of several phytochemicals. KSCEE displayed about 76% of DPPH scavenging activity with an IC₅₀ value of 34.94 µg/ml. KSCEE significantly (***p < 0.001) normalized the stress markers such as lipid peroxidation, protein carbonyl content, superoxide dismutase, and catalase in sodium nitrite and diclofenac-induced oxidative stress in RBC, platelets, liver, kidney, and small intestine, respectively. Furthermore, KSCEE was found to protect the diclofenac-induced tissue destruction of the liver, kidney, and small intestine obtained from seven groups of female Sprague Dawely rats. KSCEE delayed the clotting time of platelet-rich plasma and platelet-poor plasma and activated partial thromboplastin time, suggesting its anticoagulant property. In addition, KSCEE also exhibited antiplatelet activity by inhibiting both adenosine diphosphate and epinephrine-induced platelet aggregation. In conclusion, KSCEE ameliorates the sodium nitrite and diclofenac-induced oxidative stress in red blood cells, platelets, and experimental animals along with antithrombotic properties.

Hyperactive immature state and differential CXCR2 expression of neutrophils in severe COVID-19

Neutrophils are vital in defence against pathogens, but excessive neutrophil activity can lead to tissue damage and promote acute respiratory distress syndrome. COVID-19 is associated with systemic expansion of immature neutrophils, but the functional consequences of this shift to immaturity are not understood. We used flow cytometry to investigate activity and phenotypic diversity of circulating neutrophils in acute and convalescent COVID-19 patients. First, we demonstrate hyperactivation of immature CD10^- subpopulations in severe disease, with elevated markers of secondary granule release. Partially activated immature neutrophils were detectable 12 wk post-hospitalisation, indicating long term myeloid dysregulation in convalescent COVID-19 patients. Second, we demonstrate that neutrophils from moderately ill patients down-regulate the chemokine receptor CXCR2, whereas neutrophils from severely ill individuals fail to do so, suggesting an altered ability for organ trafficking and a potential mechanism for induction of disease tolerance. CD10^- and CXCR2^hi neutrophil subpopulations were enriched in severe disease and may represent prognostic biomarkers for the identification of individuals at high risk of progressing to severe COVID-19.

Myeloid-Derived Suppressor Cells in Cancer and COVID-19 as Associated with Oxidative Stress

Myeloid-derived suppressor cells MDSCs are a heterogeneous population of cells that expand beyond their physiological regulation during pathologies such as cancer, inflammation, bacterial, and viral infections. Their key feature is their remarkable ability to suppress T cell and natural killer NK cell responses. Certain risk factors for severe COVID-19 disease, such as obesity and diabetes, are associated with oxidative stress. The resulting inflammation and oxidative stress can negatively impact the host. Similarly, cancer cells exhibit a sustained increase in intrinsic ROS generation that maintains the oncogenic phenotype and drives tumor progression. By disrupting endoplasmic reticulum calcium channels, intracellular ROS accumulation can disrupt protein folding and ultimately lead to proteostasis failure. In cancer and COVID-19, MDSCs consist of the same two subtypes (PMN-MSDC and M-MDSC). While the main role of polymorphonuclear MDSCs is to dampen the response of T cells and NK killer cells, they also produce reactive oxygen species ROS and reactive nitrogen species RNS. We here review the origin of MDSCs, their expansion mechanisms, and their suppressive functions in the context of cancer and COVID-19 associated with the presence of superoxide anion •O2- and reactive oxygen species ROS.

A proteomic perspective and involvement of cytokines in SARS-CoV-2 infection

Infection with the SARS-CoV-2 virus results in manifestation of several clinical observations from asymptomatic to multi-organ failure. Biochemically, the serious effects are due to what is described as cytokine storm. The initial infection region for COVID-19 is the nasopharyngeal/oropharyngeal region which is the site where samples are taken to examine the presence of virus. We have now carried out detailed proteomic analysis of the nasopharyngeal/oropharyngeal swab samples collected from normal individuals and those tested positive for SARS-CoV-2, in India, during the early days of the pandemic in 2020, by RTPCR, involving high throughput quantitative proteomics analysis. Several proteins like annexins, cytokines and histones were found differentially regulated in the host human cells following SARS-CoV-2 infection. Genes for these proteins were also observed to be differentially regulated when their expression was analyzed. Majority of the cytokine proteins were found to be up regulated in the infected individuals. Cell to Cell signaling interaction, Immune cell trafficking and inflammatory response pathways were found associated with the differentially regulated proteins based on network pathway analysis.

The favorable impacts of silibinin polyphenols as adjunctive therapy in reducing the complications of COVID-19: A review of research evidence and underlying mechanisms

The proceeding pandemic of coronavirus disease 2019 is the latest global challenge. Like most other infectious diseases, inflammation, oxidative stress, and immune system dysfunctions play a pivotal role in the pathogenesis of COVID-19. Furthermore, the quest of finding a potential pharmaceutical therapy for preventing and treating COVID-19 is still ongoing. Silymarin, a mixture of flavonolignans extracted from the milk thistle, has exhibited numerous therapeutic benefits. We reviewed the beneficial effects of silymarin on oxidative stress, inflammation, and the immune system, as primary factors involved in the pathogenesis of COVID-19. We searched PubMed/Medline, Web of Science, Scopus, and Science Direct databases up to April 2022 using the relevant keywords. In summary, the current review indicates that silymarin might exert therapeutic effects against COVID-19 by improving the antioxidant system, attenuating inflammatory response and respiratory distress, and enhancing immune system function. Silymarin can also bind to target proteins of SARS-CoV-2, including main protease, spike glycoprotein, and RNA-dependent RNA-polymerase, leading to the inhibition of viral replication. Although multiple lines of evidence suggest the possible promising impacts of silymarin in COVID-19, further clinical trials are encouraged.