Therapeutic blockade of inflammation in severe COVID-19 infection with intravenous N-acetylcysteine

Pharmacology of Hydrogen Sulfide and Its Donors in Cardiometabolic Diseases

Cardiometabolic diseases (CMDs) are major contributors to global mortality, emphasizing the critical need for novel therapeutic interventions. Hydrogen sulfide (H2S) has garnered enormous attention as a significant gasotransmitter with various physiological, pathophysiological, and pharmacological impacts within mammalian cardiometabolic systems. In addition to its roles in attenuating oxidative stress and inflammatory response, burgeoning research emphasizes the significance of H2S in regulating proteins via persulfidation, a well known modification intricately associated with the pathogenesis of CMDs. This review seeks to investigate recent updates on the physiological actions of endogenous H2S and the pharmacological roles of various H2S donors in addressing diverse aspects of CMDs across cellular, animal, and clinical studies. Of note, advanced methodologies, including multiomics, intestinal microflora analysis, organoid, and single-cell sequencing techniques, are gaining traction due to their ability to offer comprehensive insights into biomedical research. These emerging approaches hold promise in characterizing the pharmacological roles of H2S in health and diseases. We will critically assess the current literature to clarify the roles of H2S in diseases while also delineating the opportunities and challenges they present in H2S-based pharmacotherapy for CMDs. SIGNIFICANCE STATEMENT: This comprehensive review covers recent developments in H2S biology and pharmacology in cardiometabolic diseases CMDs. Endogenous H2S and its donors show great promise for the management of CMDs by regulating numerous proteins and signaling pathways. The emergence of new technologies will considerably advance the pharmacological research and clinical translation of H2S.

Delineation of the role of G6PD in Alzheimer's disease and potential enhancement through microfluidic and nanoparticle approaches

Alzheimer's disease (AD) is a neurodegenerative pathologic entity characterized by the abnormal presence of tau and macromolecular Aβ deposition that leads to the degeneration or death of neurons. In addition to that, glucose-6-phosphate dehydrogenase (G6PD) has a multifaceted role in the process of AD development, where it can be used as both a marker and a target. G6PD activity is dysregulated due to its contribution to oxidative stress, neuroinflammation, and neuronal death. In this context, the current review presents a vivid depiction of recent findings on the relationship between AD progression and changes in the expression or activity of G6PD. The efficacy of the proposed G6PD-based therapeutics has been demonstrated in multiple studies using AD mouse models as representative animal model systems for cognitive decline and neurodegeneration associated with this disease. Innovative therapeutic insights are made for the boosting of G6PD activity via novel innovative nanotechnology and microfluidics tools in drug administration technology. Such approaches provide innovative methods of surpassing the blood-brain barrier, targeting step-by-step specific neural pathways, and overcoming biochemical disturbances that accompany AD. Using different nanoparticles loaded with G6DP to target specific organs, e.g., G6DP-loaded liposomes, enhances BBB penetration and brain distribution of G6DP. Many nanoparticles, which are used for different purposes, are briefly discussed in the paper. Such methods to mimic BBB on organs on-chip offer precise disease modeling and drug testing using microfluidic chips, requiring lower sample amounts and producing faster findings compared to conventional techniques. There are other contributions to microfluid in AD that are discussed briefly. However, there are some limitations accompanying microfluidics that need to be worked on to be used for AD. This study aims to bridge the gap in understanding AD with the synergistic use of promising technologies; microfluid and nanotechnology for future advancements.

N-acetyl Cysteine Overdose Induced Acute Toxicity and Hepatic Microvesicular Steatosis by Disrupting GSH and Interfering Lipid Metabolisms in Normal Mice

N-acetyl cysteine (NAC) is a versatile drug used in various conditions, but the limitations and toxicities are not clear. The acute toxicity and toxicological mechanisms of an intraperitoneal injection of NAC in normal mice were deciphered. The LD50 for male and female BALB/cByJNarl mice were 800 mg/kg and 933 mg/kg. The toxicological mechanisms of 800 mg/kg NAC (N800) were investigated. The serum biomarkers of hepatic and renal indices dramatically increased, followed by hepatic microvesicular steatosis, renal tubular injury and necrosis, and splenic red pulp atrophy and loss. Thus, N800 resulted in mouse mortality mainly due to acute liver, kidney, and spleen damages. The safe dose (275 mg/kg) of NAC (N275) increased hepatic antioxidant capacity by increasing glutathione levels and catalase activity. N275 elevated the hepatic gene expressions of lipid transporter, lipid synthesis, β-oxidation, and ketogenesis, suggesting a balance between lipid production and consumption, and finally, increased ATP production. In contrast, N800 increased hepatic oxidative stress by decreasing glutathione levels through suppressing Gclc, and reducing catalase activity. N800 decreased the hepatic gene expressions of lipid transporter, lipid synthesis, and interferred β-oxidation, leading to lipid accumulation and increasing Cyp2E1 expression, and finally, decreased ATP production. Therefore, NAC doses are limited for normal individuals, especially via intraperitoneal injection or similar means.

Conformational perturbation of SARS-CoV-2 spike protein using N-acetyl cysteine: an exploration of probable mechanism of action to combat COVID-19

The infection caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) resulted in a pandemic with huge death toll and economic consequences. The virus attaches itself to the human epithelial cells through noncovalent bonding of its spike protein with the angiotensin-converting enzyme-2 (ACE2) receptor on the host cell. Based on in silico studies we hypothesized that perturbing the functionally active conformation of spike protein through the reduction of its solvent accessible disulfide bonds, thereby disintegrating its structural architecture, may be a feasible strategy to prevent infection by reducing the binding affinity towards ACE2 enzyme. Proteomics data showed that N-acetyl cysteine (NAC), an antioxidant and mucolytic agent been widely in use in clinical medicine, forms covalent conjugates with solvent accessible cysteine residues of spike protein that were disulfide bonded in the native state. Further, in silico analysis indicated that the presence of the selective covalent conjugation of NAC with Cys525 perturbed the stereo specific orientations of the interacting key residues of spike protein that resulted in threefold weakening in the binding affinity of spike protein with ACE2 receptor. Interestingly, almost all SARS-CoV-2 variants conserved cystine residues in the spike protein. Our finding results possibly provides a molecular basis for identifying NAC and/or its analogues for targeting Cys-525 of the viral spike protein as fusion inhibitor and exploring in vivo pharmaco-preventive and its therapeutic potential activity for COVID-19 disease. However, in-vitro assay and animal model-based experiment are required to validate the probable mechanism of action.Communicated by Ramaswamy H. Sarma.

Exploring the Interplay of Food Security, Safety, and Psychological Wellness in the COVID-19 Era: Managing Strategies for Resilience and Adaptation

The global population surge presents a dual challenge and opportunity in the realms of food consumption, safety, and mental well-being. This necessitates a projected 70% increase in food production to meet growing demands. Amid this backdrop, the ongoing COVID-19 pandemic exacerbates these issues, underscoring the need for a deeper understanding of the intricate interplay between food consumption patterns and mental health dynamics during this crisis. Mitigating the spread of COVID-19 hinges upon rigorous adherence to personal hygiene practices and heightened disease awareness. Furthermore, maintaining stringent food quality and safety standards across both public and private sectors is imperative for safeguarding public health and containing viral transmission. Drawing upon existing research, this study delves into the pandemic's impact on mental health, food consumption habits, and food safety protocols. Through a comprehensive analysis, it aims to elucidate the nuanced relationship among food, food safety, and mental well-being amid the COVID-19 pandemic, highlighting synergistic effects and dynamics that underpin holistic human welfare. Our study offers a novel approach by integrating psychological wellness with food security and safety. In conceiving this review, we aimed to comprehensively explore the intricate interplay among food security, safety, and psychological wellness amid the backdrop of the COVID-19 pandemic. Our review is structured to encompass a thorough examination of existing research, synthesizing insights into the multifaceted relationships among food consumption patterns, mental health dynamics, and food safety protocols during the crisis. Our findings provide valuable insights and practical recommendations for enhancing food security and psychological well-being, thus supporting both academic research and real-world applications in crisis management and policy development.

Precision nutrition to reset virus-induced human metabolic reprogramming and dysregulation (HMRD) in long-COVID

SARS-CoV-2, the etiological agent of COVID-19, is devoid of any metabolic capacity; therefore, it is critical for the viral pathogen to hijack host cellular metabolic machinery for its replication and propagation. This single-stranded RNA virus with a 29.9 kb genome encodes 14 open reading frames (ORFs) and initiates a plethora of virus-host protein-protein interactions in the human body. These extensive viral protein interactions with host-specific cellular targets could trigger severe human metabolic reprogramming/dysregulation (HMRD), a rewiring of sugar-, amino acid-, lipid-, and nucleotide-metabolism(s), as well as altered or impaired bioenergetics, immune dysfunction, and redox imbalance in the body. In the infectious process, the viral pathogen hijacks two major human receptors, angiotensin-converting enzyme (ACE)-2 and/or neuropilin (NRP)-1, for initial adhesion to cell surface; then utilizes two major host proteases, TMPRSS2 and/or furin, to gain cellular entry; and finally employs an endosomal enzyme, cathepsin L (CTSL) for fusogenic release of its viral genome. The virus-induced HMRD results in 5 possible infectious outcomes: asymptomatic, mild, moderate, severe to fatal episodes; while the symptomatic acute COVID-19 condition could manifest into 3 clinical phases: (i) hypoxia and hypoxemia (Warburg effect), (ii) hyperferritinemia ('cytokine storm'), and (iii) thrombocytosis (coagulopathy). The mean incubation period for COVID-19 onset was estimated to be 5.1 days, and most cases develop symptoms after 14 days. The mean viral clearance times were 24, 30, and 39 days for acute, severe, and ICU-admitted COVID-19 patients, respectively. However, about 25-70% of virus-free COVID-19 survivors continue to sustain virus-induced HMRD and exhibit a wide range of symptoms that are persistent, exacerbated, or new 'onset' clinical incidents, collectively termed as post-acute sequelae of COVID-19 (PASC) or long COVID. PASC patients experience several debilitating clinical condition(s) with >200 different and overlapping symptoms that may last for weeks to months. Chronic PASC is a cumulative outcome of at least 10 different HMRD-related pathophysiological mechanisms involving both virus-derived virulence factors and a multitude of innate host responses. Based on HMRD and virus-free clinical impairments of different human organs/systems, PASC patients can be categorized into 4 different clusters or sub-phenotypes: sub-phenotype-1 (33.8%) with cardiac and renal manifestations; sub-phenotype-2 (32.8%) with respiratory, sleep and anxiety disorders; sub-phenotype-3 (23.4%) with skeleto-muscular and nervous disorders; and sub-phenotype-4 (10.1%) with digestive and pulmonary dysfunctions. This narrative review elucidates the effects of viral hijack on host cellular machinery during SARS-CoV-2 infection, ensuing detrimental effect(s) of virus-induced HMRD on human metabolism, consequential symptomatic clinical implications, and damage to multiple organ systems; as well as chronic pathophysiological sequelae in virus-free PASC patients. We have also provided a few evidence-based, human randomized controlled trial (RCT)-tested, precision nutrients to reset HMRD for health recovery of PASC patients.

Clinical efficacy of N-acetylcysteine for COVID-19: A systematic review and meta-analysis of randomized controlled trials

Background

The association between N-acetylcysteine (NAC) and COVID-19 remains undetermined; therefore, this meta-analysis assessed the clinical efficacy of NAC in the treatment of patients with COVID-19.

Methods

This study searched PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov for studies published from their inception to December 17, 2022. Only randomized controlled trials (RCTs) that assessed the clinical efficacy of NAC for patients with COVID-19 were included.

Results

Five RCTs involving 651 patients were included. There was no significant difference in mortality between the study group receiving NAC and the control group (15.6 % [50/320] vs. 32.3 %, [107/331]; risk ratio [RR]: 0.58; 95 % confidence interval [CI]: 0.24-1.40). In addition, the two groups did not differ with respect to the incidence of invasive mechanical ventilation (RR: 0.93; 95 % CI: 0.65-1.33), the risk of intensive care unit (ICU) admission (RR: 0.86; 95 % CI: 0.62-1.21), the length of hospital stay (mean difference [MD]: 0.17 days; 95 % CI: -0.67-1.01), and the length of ICU stay (MD: -0.77 days; 95 % CI: -2.97-1.42).

Conclusions

The administration of NAC did not improve the clinical outcomes of patients with COVID-19; its routine use is not recommended for patients with SARS-CoV-2 infections.

TXM peptides inhibit SARS-CoV-2 infection, syncytia formation, and lower inflammatory consequences

After three years of the SARS-CoV-2 pandemic, the search and availability of relatively low-cost benchtop therapeutics for people not at high risk for a severe disease are still ongoing. Although vaccines and new SARS-CoV-2 variants reduce the death toll, the long COVID-19 along with neurologic symptoms can develop and persist even after a mild initial infection. Reinfections, which further increase the risk of sequelae in multiple organ systems as well as the risk of death, continue to require caution. The spike protein of SARS-CoV-2 is an important target for both vaccines and therapeutics. The presence of disulfide bonds in the receptor binding domain (RBD) of the spike protein is essential for its binding to the human ACE2 receptor and cell entry. Here, we demonstrate that thiol-reducing peptides based on the active site of oxidoreductase thioredoxin 1, called thioredoxin mimetic (TXM) peptides, can prevent syncytia formation, SARS-CoV-2 entry into cells, and infection in a mouse model. We also show that TXM peptides inhibit the redox-sensitive HIV pseudotyped viral cell entry. These results support disulfide targeting as a common therapeutic strategy for treating infections caused by viruses using redox-sensitive fusion. Furthermore, TXM peptides exert anti-inflammatory properties by lowering the activation of NF-κB and IRF signaling pathways, mitogen-activated protein kinases (MAPKs) and lipopolysaccharide (LPS)-induced cytokines in mice. The antioxidant and anti-inflammatory effects of the TXM peptides, which also cross the blood-brain barrier, in combination with prevention of viral infections, may provide a beneficial clinical strategy to lower viral infections and mitigate severe consequences of COVID-19.

Signaling pathways and potential therapeutic targets in acute respiratory distress syndrome (ARDS)

Acute respiratory distress syndrome (ARDS) is a common condition associated with critically ill patients, characterized by bilateral chest radiographical opacities with refractory hypoxemia due to noncardiogenic pulmonary edema. Despite significant advances, the mortality of ARDS remains unacceptably high, and there are still no effective targeted pharmacotherapeutic agents. With the outbreak of coronavirus disease 19 worldwide, the mortality of ARDS has increased correspondingly. Comprehending the pathophysiology and the underlying molecular mechanisms of ARDS may thus be essential to developing effective therapeutic strategies and reducing mortality. To facilitate further understanding of its pathogenesis and exploring novel therapeutics, this review provides comprehensive information of ARDS from pathophysiology to molecular mechanisms and presents targeted therapeutics. We first describe the pathogenesis and pathophysiology of ARDS that involve dysregulated inflammation, alveolar-capillary barrier dysfunction, impaired alveolar fluid clearance and oxidative stress. Next, we summarize the molecular mechanisms and signaling pathways related to the above four aspects of ARDS pathophysiology, along with the latest research progress. Finally, we discuss the emerging therapeutic strategies that show exciting promise in ARDS, including several pharmacologic therapies, microRNA-based therapies and mesenchymal stromal cell therapies, highlighting the pathophysiological basis and the influences on signal transduction pathways for their use.

Reactive Oxygen Species Scavenging Nanozymes: Emerging Therapeutics for Acute Liver Injury Alleviation

Acute liver injury (AIL), a fatal clinical disease featured with a swift deterioration of hepatocyte functions in the short term, has emerged as a serious public health issues that warrants attention. However, the effectiveness of existing small molecular antioxidants and anti-inflammatory medications in alleviating AIL remains uncertain. The unique inherent structural characteristics of liver confer it a natural propensity for nanoparticle capture, which present an opportunity to exploit in the formulation of nanoscale therapeutic agents, enabling their selective accumulation in the liver and thereby facilitating targeted therapeutic interventions. Significantly increased reactive oxygen species (ROS) accumulation and inflammation response have been evidenced to play crucial roles in occurrence and development of AIL. Nanozymes with ROS-scavenging capacities have demonstrated considerable promise in ROS elimination and inflammation regulation, thereby offering an appealing therapeutic instrument for the management of acute liver injury. In this review, the mechanisms of different type of ALI were summarized. In addition, we provide a comprehensive summary and review of the available ROS-scavenging nanozymes, including transition metal-based nanozymes, noble metal nanozymes, carbon-based nanozymes, and some other nanozymes. Furthermore, the challenges still need to be solved in the field of ROS-scavenging nanozymes for ALI alleviation are also discussed.

Protective role of N-acetylcysteine and Sulodexide on endothelial cells exposed on patients' serum after SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus-2 causes hyperinflammation and activation of coagulation cascade and, as a result, aggravates endothelial cell dysfunction. N-acetylcysteine and Sulodexide have been found to mitigate endothelial damage. The influence on coronary artery endothelial cells of serum collected after 4 ± 1 months from coronavirus infection was studied. The concentrations of serum samples of interleukin 6, von Willebrand Factor, tissue Plasminogen Activator, and Plasminogen Activator Inhibitor-1 were studied. The cultures with serum of patients after coronavirus infection were incubated with N-acetylcysteine and Sulodexide to estimate their potential protective role. The blood inflammatory parameters were increased in the group of cultures incubated with serum from patients after coronavirus infection. Supplementation of the serum from patients after coronavirus infection with N-acetylcysteine or Sulodexide reduced the synthesis of interleukin 6 and von Willebrand Factor. No changes in the synthesis of tissue Plasminogen Activator were observed. N-acetylcysteine reduced the synthesis of Plasminogen Activator Inhibitor-1. N-acetylcysteine and Sulodexide increased the tPA/PAI-1 ratio. N-acetylcysteine may have a role in reducing the myocardial injury occurring in the post-COVID-19 syndrome. Sulodexide can also play a protective role in post-COVID-19 patients.

The potential role of ferroptosis in COVID-19-related cardiovascular injury

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged as a global health threat in 2019. An important feature of the disease is that multiorgan symptoms of SARS-CoV-2 infection persist after recovery. Evidence indicates that people who recovered from COVID-19, even those under the age of 65 years without cardiovascular risk factors such as smoking, obesity, hypertension, and diabetes, had a significantly increased risk of cardiovascular disease for up to one year after diagnosis. Therefore, it is important to closely monitor individuals who have recovered from COVID-19 for potential cardiovascular damage that may manifest at a later stage. Ferroptosis is an iron-dependent form of non-apoptotic cell death characterized by the production of reactive oxygen species (ROS) and increased lipid peroxide levels. Several studies have demonstrated that ferroptosis plays an important role in cancer, ischemia/reperfusion injury (I/RI), and other cardiovascular diseases. Altered iron metabolism, upregulation of reactive oxygen species, and glutathione peroxidase 4 inactivation are striking features of COVID-19-related cardiovascular injury. SARS-CoV-2 can cause cardiovascular ferroptosis, leading to cardiovascular damage. Understanding the mechanism of ferroptosis in COVID-19-related cardiovascular injuries will contribute to the development of treatment regimens for preventing or reducing COVID-19-related cardiovascular complications. In this article, we go over the pathophysiological underpinnings of SARS-CoV-2-induced acute and chronic cardiovascular injury, the function of ferroptosis, and prospective treatment approaches.

Evaluation of the efficacy and safety of oral N-acetylcysteine in patients with COVID-19 receiving the routine antiviral and hydroxychloroquine protocol: A randomized controlled clinical trial

BACKGROUND

The current absence of gold-standard or all-aspect favorable therapies for COVID-19 renders a focus on multipotential drugs proposed to prevent or treat this infection or ameliorate its signs and symptoms vitally important. The present well-designed randomized controlled trial (RCT) sought to evaluate the efficacy and safety of N-acetylcysteine (NAC) as adjuvant therapy for 60 hospitalized Iranian patients with COVID-19.

METHODS

Two 30-person diets, comprising 15 single diets of Kaletra (lopinavir/ritonavir) + hydroxychloroquine (HCQ) with/without NAC (600 mg TDS) and atazanavir/ritonavir + HCQ with/without NAC (600 mg TDS), were administered in the study.

RESULTS

At the end of the study, a further decrease in C-reactive protein was observed in the NAC group (P = 0.008), and no death occurred in the atazanavir/ritonavir + HCQ + NAC group, showing that the combination of these drugs may reduce mortality. The atazanavir/ritonavir + HCQ and atazanavir/ritonavir + NAC groups exhibited the highest O2 saturation at the end of the study and a significant rise in O2 saturation following intervention commencement, including NAC (P > 0.05). Accordingly, oral or intravenous NAC, if indicated, may enhance O2 saturation, blunt the inflammation trend (by reducing C-reactive protein), and lower mortality in hospitalized patients with COVID-19.

CONCLUSION

The NAC could be more effective as prophylactic or adjuvant therapy in stable non-severe cases of COVID-19 with a particularly positive role in the augmentation of O2 saturation and faster reduction of the CRP level and inflammation or could be effective for better controlling of COVID-19 or its therapy-related side effects.

Causal influences of osteoarthritis on COVID-19: a Mendelian randomization study

Objective

Although observational and genetic studies have indicated a correlation between OA and COVID-19, it remains uncertain whether osteoarthritis (OA) contributes to the severity of COVID-19. Here, we aimed to investigate the potential causal links between the two.

Methods

In this study, we conducted Mendelian randomization (MR) analysis to investigate whether there is a potential causal connection between OA and COVID-19 outcomes. The analysis utilized publicly available GWAS summary datasets, incorporating data on OA (N = 455,221), SARS-CoV-2 infection (N = 2,597,856), hospitalized COVID-19 (N = 2,095,324), and critical COVID-19 (N = 1,086,211). Additionally, we performed a literature analysis to establish a molecular network connecting OA and COVID-19.

Results

The MR analysis showed causal effects of OA on hospitalized COVID-19 (OR: 1.21, 95% CI: 1.02-1.43, p = 0.026) and critical COVID-19 (OR: 1.35, 95% CI: 1.09-1.68, p = 0.006) but not on SARS-CoV-2 infection as such (OR: 1.00, 95% CI: 0.92-1.08, p = 0.969). Moreover, the literature-based pathway analysis uncovered a set of specific genes, such as CALCA, ACE, SIRT1, TNF, IL6, CCL2, and others, that were found to mediate the association between OA and COVID-19.

Conclusion

Our findings indicate that OA elevates the risk of severe COVID-19. Therefore, larger efforts should be made in the prevention of COVID-19 in OA patients.

N-Acetylcysteine and Its Immunomodulatory Properties in Humans and Domesticated Animals

N-acetylcysteine (NAC), an acetylated derivative of the amino acid L-cysteine, has been widely used as a mucolytic agent and antidote for acetaminophen overdose since the 1960s and the 1980s, respectively. NAC possesses antioxidant, cytoprotective, anti-inflammatory, antimicrobial, and mucolytic properties, making it a promising therapeutic agent for a wide range of diseases in both humans and domesticated animals. Oxidative stress and inflammation play a major role in the onset and progression of all these diseases. NAC's primary role is to replenish glutathione (GSH) stores, the master antioxidant in all tissues; however, it can also reduce levels of pro-inflammatory tumor necrosis factor-alpha (TNF-∝) and interleukins (IL-6 and IL-1β), inhibit the formation of microbial biofilms and destroy biofilms, and break down disulfide bonds between mucin molecules. Many experimental studies have been conducted on the use of NAC to address a wide range of pathological conditions; however, its effectiveness in clinical trials remains limited and studies often have conflicting results. The purpose of this review is to provide a concise overview of promising NAC usages for the treatment of different human and domestic animal disorders.

The acute effect of different NAD+ precursors included in the combined metabolic activators

NAD+ and glutathione precursors are currently used as metabolic modulators for improving the metabolic conditions associated with various human diseases, including non-alcoholic fatty liver disease, neurodegenerative diseases, mitochondrial myopathy, and age-induced diabetes. Here, we performed a one-day double blinded, placebo-controlled human clinical study to assess the safety and acute effects of six different Combined Metabolic Activators (CMAs) with 1 g of different NAD+ precursors based on global metabolomics analysis. Our integrative analysis showed that the NAD+ salvage pathway is the main source for boosting the NAD+ levels with the administration of CMAs without NAD+ precursors. We observed that incorporation of nicotinamide (Nam) in the CMAs can boost the NAD+ products, followed by niacin (NA), nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), but not flush free niacin (FFN). In addition, the NA administration led to a flushing reaction, accompanied by decreased phospholipids and increased bilirubin and bilirubin derivatives, which could be potentially risky. In conclusion, this study provided a plasma metabolomic landscape of different CMA formulations, and proposed that CMAs with Nam, NMN as well as NR can be administered for boosting NAD+ levels to improve altered metabolic conditions.

N-acetylcysteine reduces severity and mortality in COVID-19 patients: A systematic review and meta-analysis

Objectives

Recent clinical studies suggest that oxidative stress is one of the key players in the pathogenesis of coronavirus disease 2019 (COVID-19), and N-acetylcysteine (NAC), a potent antioxidant, has been shown to improve clinical outcomes in COVID-19 patients. We conducted a systematic review and meta-analysis of the literature published on the therapeutic intervention of NAC on COVID-19 infection.

Methods

We searched PubMed, Google Scholar, and Science Direct. We identified and screened eight studies with 20,503 participants, including 2,852 in the NAC-treated group and 17,651 in the placebo group, which reported the effect of NAC on COVID-19 infection. A meta-analysis was performed using forest plots under fixed effect estimates based on the standardized mean difference (SMD) and risk ratio (RR).

Results

Pooled analysis showed that NAC was associated with lower mortality in patients with COVID-19 compared with the placebo group [RR, 0.65; (95% CI: 0.56 to 0.75); p < 0.0001]. Similarly, C-reactive protein (CRP) [SMD, -0.32; (95% CI: -56 to -0.09); p = 0.0070] and D-dimer [SMD, -0.35, (95% CI: -0.59 to -0.10; p = 0.0062] levels were significantly decreased, and the oxygenation marker, PaO2/FiO2 ratio, was increased in the NAC-treated group compared with the placebo group [SMD, 0.76; (95% CI: 0.48 to 1.03); p < 0.0001].

Conclusion

Although the number of included studies was minimal, this meta-analysis suggests that NAC may have a positive effect on COVID-19 outcomes, specifically, a significant decrease in CRP and D-dimer levels and a significant increase in oxygen saturation, which decreased mortality. We have also presented a comprehensive review of the role and mechanisms of NAC in patients with COVID-19.

Response to Intravenous N-Acetylcysteine Supplementation in Critically Ill Patients with COVID-19

Administering N-acetylcysteine (NAC) could counteract the effect of free radicals, improving the clinical evolution of patients admitted to the Intensive Care Unit (ICU). This study aimed to investigate the clinical and biochemical effects of administering NAC to critically ill patients with COVID-19. A randomized controlled clinical trial was conducted on ICU patients (n = 140) with COVID-19 and divided into two groups: patients treated with NAC (NAC-treated group) and patients without NAC treatment (control group). NAC was administered as a continuous infusion with a loading dose and a maintenance dose during the study period (from admission until the third day of ICU stay). NAC-treated patients showed higher PaO₂/FiO₂ (p ≤ 0.014) after 3 days in ICU than their control group counterparts. Moreover, C-reactive protein (p ≤ 0.001), D-dimer (p ≤ 0.042), and lactate dehydrogenase (p ≤ 0.001) levels decreased on the third day in NAC-treated patients. Glutathione concentrations decreased in both NAC-treated (p ≤ 0.004) and control (p ≤ 0.047) groups after 3 days in ICU; whereas glutathione peroxidase did not change during the ICU stay. The administration of NAC manages to improve the clinical and analytical response of seriously ill patients with COVID-19 compared to the control group. NAC is able to stop the decrease in glutathione concentrations.

Investigation of supplement products preferred by healthcare professionals during COVID-19 pandemic process

Objective: Various products are used to strengthen immunity in prevention and treatment during the COVID-19 pandemic affecting the whole world, which has no cure yet, and the vaccine has just been used. This study was planned to learn about the supplements used by healthcare professionals. Methods: A questionnaire was applied to the physicians, nurses, technicians, secretaries, and staff working in the operating room, intensive care, ward, and outpatient clinic by e-mail, WhatsApp, or face-to-face interview method. Results: There was no difference between the groups in terms of being COVID-19-positive. The most used products were primarily Mg and vitamin D, and vitamin C, ginger, Zn, turmeric, green tea, vitamin complex, thyme, black elderberry (sambucus nigra), propolis, prebiotic/probiotic, acetylsalicylic acid (ASA), black cumin (niger sativa), N-acetyl cysteine (NAC), selenium (Se), Coenzyme-Q10, cinnamon, glutathione (GSH) and quercetin respectively. No one had used alpha lipoic acid (ALA). The products that showed significant differences between the groups with and without COVID-19 were vitamin C, prebiotic/probiotic, propolis and ASA. Conclusıon: Since it is not asked when the product is used, although it is not possible to evaluate its effectiveness for preventive or therapeutic purposes, known to be natural, inexpensive, and easily accessible antiviral products may be preferred.

Efficacy of N-acetyl Cysteine in Severe COVID-19 Patients: A Randomized Controlled Phase III Clinical Trial

Background: Today, various drugs have been investigated as the primary or complementary treatment for coronavirus disease 2019 (COVID-19). N-acetylcysteine (NAC) has been used as a mucolytic in pulmonary diseases. This drug apparently contributes to the retrieval of the intracellular antioxidant system. Objectives: This study aimed to determine the efficacy of NAC in severe COVID-19 patients admitted to the intensive care unit (ICU). Methods: This single-blinded randomized controlled phase III clinical trial included 40 patients with confirmed COVID-19 (based on polymerase chain reaction) admitted to the Shahid Mohammadi Hospital’s ICU, Bandar Abbas, Iran, in 2020. All cases had severe COVID-19. They were allocated randomly to two equal groups. Patients in the control group received standard drug therapy based on the treatment protocol of the national COVID-19 committee, while those in the NAC group received a single dose of intravenous NAC (300 mg/kg) upon admission to the ICU in addition to standard drug treatment. Clinical status and laboratory tests were done on admission to the ICU and then 14 days later or at discharge without knowing the patient grouping. Results: The two groups were comparable regarding age, gender, and other baseline laboratory and clinical parameters. At the final evaluation, respiratory rate (21.25 ± 4.67 vs. 27.37 ± 6.99 /min) and D-dimer (186.37 ± 410.23 vs. 1339.04 ± 2183.87 ng/mL) were significantly lower in the NAC group (P = 0.004 and P = 0.030, respectively). Also, a lower percentage of patients in the NAC group had lactate dehydrogenase (LDH) ≤ 245 U/L (0% vs. 25%, P = 0.047). Although the length of ward and ICU stay was shorter in the NAC group than in controls, the difference was statistically insignificant (P = 0.598 and P = 0.629, respectively). Mortality, on the other hand, was 75% in the control group and 50% in the NAC group, with no statistically significant difference (P = 0.102). Concerning the change in the study parameters, only the decrease in diastolic blood pressure (DBP) was significantly higher with NAC (P = 0.042). The intubation and mechanical ventilation rates were higher, while oxygen with mask and nasal oxygen rates were lower with NAC, but the difference was statistically insignificant. Conclusions: Based on the current research, NAC is related to a significant decrease in RR, D-dimer, and DBP in severe COVID-19. Also, LDH was significantly lower in the NAC group than in the controls. More research with larger sample sizes is needed to validate the current study results.

N-acetylcysteine for prevention and treatment of COVID-19: Current state of evidence and future directions

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes coronavirus disease 2019 (COVID-19) and can be associated with serious complications, including acute respiratory distress syndrome. This condition is accompanied by a massive release of cytokines, also denominated cytokine storm, development of systemic oxidative stress and a prothrombotic state. In this context, it has been proposed a role for acetylcysteine (NAC) in the management of patients with COVID-19. NAC is a molecule classically known for its mucolytic effect, but it also has direct and indirect antioxidant activity as a precursor of reduced glutathione. Other effects of NAC have also been described, such as modulating the immune and inflammatory response, counteracting the thrombotic state, and having an antiviral effect. The pharmacological activities of NAC and its effects on the mechanisms of disease progression make it a potential therapeutic agent for COVID-19. NAC is safe, tolerable, affordable, and easily available. Moreover, the antioxidant effects of the molecule may even prevent infection and play an important role as a complement to vaccination. Although the clinical efficacy and dosing regimens of NAC have been evaluated in the clinical setting with small series of patients, the results are promising. In this article, we review the pathogenesis of SARS-CoV-2 infection and the current knowledge of the mechanisms of action of NAC across disease stages. We also propose NAC posology strategies to manage COVID-19 patients in different clinical scenarios.

N-acetylcysteine Reduces Inflammasome Activation Induced by SARS-CoV-2 Proteins In Vitro

Inflammasome activation is one of the first steps in initiating innate immune responses. In this work, we studied the activation of inflammasomes in the airways of critically ill COVID-19 patients and the effects of N-acetylcysteine (NAC) on inflammasomes. Tracheal biopsies were obtained from critically ill patients without COVID-19 and no respiratory disease (control, n = 32), SARS-CoV-2 B.1 variant (n = 31), and B.1.1.7 VOC alpha variant (n = 20) patients. Gene expression and protein expression were measured by RT-qPCR and immunohistochemistry. Macrophages and bronchial epithelial cells were stimulated with different S, E, M, and N SARS-CoV-2 recombinant proteins in the presence or absence of NAC. NLRP3 inflammasome complex was over-expressed and activated in the COVID-19 B.1.1.7 VOC variant and associated with systemic inflammation and 28-day mortality. TLR2/MyD88 and redox NOX4/Nrf2 ratio were also over-expressed in the COVID-19 B.1.1.7 VOC variant. The combination of S-E-M SARS-CoV-2 recombinant proteins increased cytokine release in macrophages and bronchial epithelial cells through the activation of TLR2. NAC inhibited SARS-CoV-2 mosaic (S-E-M)-induced cytokine release and inflammasome activation. In summary, inflammasome is over-activated in severe COVID-19 and increased in B.1.1.7 VOC variant. In addition, NAC can reduce inflammasome activation induced by SARS-CoV-2 in vitro, which may be of potential translational value in COVID-19 patients.

The Renin-Angiotensin-Aldosterone System, Nitric Oxide, and Hydrogen Sulfide at the Crossroads of Hypertension and COVID-19: Racial Disparities and Outcomes

Coronavirus disease 2019 is caused by SARS-CoV-2 and is more severe in the elderly, racial minorities, and those with comorbidities such as hypertension and diabetes. These pathologies are often controlled with medications involving the renin-angiotensin-aldosterone system (RAAS). RAAS is an endocrine system involved in maintaining blood pressure and blood volume through components of the system. SARS-CoV-2 enters the cells through ACE2, a membrane-bound protein related to RAAS. Therefore, the use of RAAS inhibitors could worsen the severity of COVID-19's symptoms, especially amongst those with pre-existing comorbidities. Although a vaccine is currently available to prevent and reduce the symptom severity of COVID-19, other options, such as nitric oxide and hydrogen sulfide, may also have utility to prevent and treat this virus.

Utility of NO and H2S donating platforms in managing COVID-19: Rationale and promise

Viral infections are a continuing global burden on the human population, underscored by the ramifications of the COVID-19 pandemic. Current treatment options and supportive therapies for many viral infections are relatively limited, indicating a need for alternative therapeutic approaches. Virus-induced damage occurs through direct infection of host cells and inflammation-related changes. Severe cases of certain viral infections, including COVID-19, can lead to a hyperinflammatory response termed cytokine storm, resulting in extensive endothelial damage, thrombosis, respiratory failure, and death. Therapies targeting these complications are crucial in addition to antiviral therapies. Nitric oxide and hydrogen sulfide are two endogenous gasotransmitters that have emerged as key signaling molecules with a broad range of antiviral actions in addition to having anti-inflammatory properties and protective functions in the vasculature and respiratory system. The enhancement of endogenous nitric oxide and hydrogen sulfide levels thus holds promise for managing both early-stage and later-stage viral infections, including SARS-CoV-2. Using SARS-CoV-2 as a model for similar viral infections, here we explore the current evidence regarding nitric oxide and hydrogen sulfide's use to limit viral infection, resolve inflammation, and reduce vascular and pulmonary damage.

Antioxidant, Anti-inflammatory, and Immunomodulatory Roles of Nonvitamin Antioxidants in Anti-SARS-CoV-2 Therapy

Viral pathologies encompass activation of pro-oxidative pathways and inflammatory burst. Alleviating overproduction of reactive oxygen species and cytokine storm in COVID-19 is essential to counteract the immunogenic damage in endothelium and alveolar membranes. Antioxidants alleviate oxidative stress, cytokine storm, hyperinflammation, and diminish the risk of organ failure. Direct antiviral roles imply: impact on viral spike protein, interference with the ACE2 receptor, inhibition of dipeptidyl peptidase 4, transmembrane protease serine 2 or furin, and impact on of helicase, papain-like protease, 3-chyomotrypsin like protease, and RNA-dependent RNA polymerase. Prooxidative environment favors conformational changes in the receptor binding domain, promoting the affinity of the spike protein for the host receptor. Viral pathologies imply a vicious cycle, oxidative stress promoting inflammatory responses, and vice versa. The same was noticed with respect to the relationship antioxidant impairment-viral replication. Timing, dosage, pro-oxidative activities, mutual influences, and interference with other antioxidants should be carefully regarded. Deficiency is linked to illness severity.

Opposite Effect of Thyroid Hormones on Oxidative Stress and on Mitochondrial Respiration in COVID-19 Patients

Background: Thyroid hormones (TH)s are master regulators of mitochondrial activity and biogenesis. Nonthyroidal illness syndrome (NTIS) is generally considered an adaptative response to reduced energy that is secondary to critical illness, including COVID-19. COVID-19 has been associated with profound changes in the cell energy metabolism, especially in the cells of the immune system, with a central role played by the mitochondria, considered the power units of every cell. Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affects and alters mitochondrial functions, both to influence its intracellular survival and to evade host immunity. Aim of the study: This study was undertaken to analyze the oxidative balance and mitochondrial respiration in COVID-19 patients with and without NTIS to elucidate the role that thyroid hormones (TH)s play in this context. Methods: In our cohort of 54 COVID-19 patients, admitted to our University Hospital during the COVID-19 pandemic, we evaluated the generation of reactive oxygen species (ROS) by measuring the serum levels of derivatives of reactive oxygen metabolites (dROMs), and we analyzed the antioxidant capacity by measuring the serum biological antioxidant potential (BAP). We then analyzed the mitochondrial respiration in peripheral blood mononuclear cells (PBMC)s of 28 of our COVID-19 patients, using the seahorse instrument (Agilent). Results were correlated with the serum levels of THs and, in particular, of FT3. In addition, the role of T3 on bioelectrical impedance analysis (BIA) and mitochondrial respiration parameters was directly evaluated in two COVID-19 patients with NTIS, in which treatment with synthetic liothyronine (LT3) was given both in vivo and in vitro. Results: In our COVID-19 patients with NTIS, the dROMs values were significantly lower and the BAP values were significantly higher. Consequently, the oxidative stress index (OSi), measured as BAP/dROMs ratio was reduced compared to that observed in COVID-19 patients without NTIS, indicating a protective role exerted by NTIS on oxidative stress. In our COVID-19 patients, the mitochondrial respiration, measured in PBMCs, was reduced compared to healthy controls. Those with NTIS showed a reduced maximal respiratory capacity and a reduced proton leak, compared to those with normal FT3 serum values. Such lowered mitochondrial respiratory capacity makes the cells more vulnerable to bioenergetic exhaustion. In a pilot study involving two COVID-19 patients with NTIS, we could reinforce our previous observation regarding the role of T3 in the maintenance of adequate peripheral hydroelectrolytic balance. In addition, in these two patients, we demonstrated that by treating their PBMCs with LT3, both in vitro and in vivo, all mitochondrial respiration parameters significantly increased. Conclusions: Our results regarding the reduction in the serum levels of the reactive oxygen species (ROS) of COVID-19 patients with NTIS support the hypothesis that NTIS could represent an adaptative response to severe COVID-19. However, beside this beneficial effect, we demonstrate that, in the presence of an acute reduction of FT3 serum levels, the mitochondrial respiration is greatly impaired, with a consequent establishment of a hypoenergetic state of the immune cells that may hamper their capacity to react to massive viral infection.

Reactive sulfur species and their significance in health and disease

Reactive sulfur species (RSS) have been recognized in the last two decades as very important molecules in redox regulation. They are involved in metabolic processes and, in this way, they are responsible for maintenance of health. This review summarizes current information about the essential biological RSS, including H₂S, low molecular weight persulfides, protein persulfides as well as organic and inorganic polysulfides, their synthesis, catabolism and chemical reactivity. Moreover, the role of RSS disturbances in various pathologies including vascular diseases, chronic kidney diseases, diabetes mellitus Type 2, neurological diseases, obesity, chronic obstructive pulmonary disease and in the most current problem of COVID-19 is presented. The significance of RSS in aging is also mentioned. Finally, the possibilities of using the precursors of various forms of RSS for therapeutic purposes are discussed.

Molecular Mechanisms Related to Responses to Oxidative Stress and Antioxidative Therapies in COVID-19: A Systematic Review

The coronavirus disease (COVID-19) pandemic is a leading global health and economic challenge. What defines the disease’s progression is not entirely understood, but there are strong indications that oxidative stress and the defense against reactive oxygen species are crucial players. A big influx of immune cells to the site of infection is marked by the increase in reactive oxygen and nitrogen species. Our article aims to highlight the critical role of oxidative stress in the emergence and severity of COVID-19 and, more importantly, to shed light on the underlying molecular and genetic mechanisms. We have reviewed the available literature and clinical trials to extract the relevant genetic variants within the oxidative stress pathway associated with COVID-19 and the anti-oxidative therapies currently evaluated in the clinical trials for COVID-19 treatment, in particular clinical trials on glutathione and N-acetylcysteine.

N-Acetylcysteine and Other Sulfur-Donors as a Preventative and Adjunct Therapy for COVID-19

The airway epithelial glycocalyx plays an important role in preventing severe acute respiratory syndrome coronavirus 2 entry into the epithelial cells, while the endothelial glycocalyx contributes to vascular permeability and tone, as well as modulating immune, inflammatory, and coagulation responses. With ample evidence in the scientific literature that coronavirus disease 2019 (COVID-19) is related to epithelial and endothelial dysfunction, preserving the glycocalyx should be the main focus of any COVID-19 treatment protocol. The most studied functional unit of the glycocalyx is the glycosaminoglycan heparan sulfate, where the degree and position of the sulfate groups determine the biological activity. N-acetylcysteine (NAC) and other sulfur donors contribute to the inorganic sulfate pool, the rate-limiting molecule in sulfation. NAC is not only a precursor to glutathione but also converts to hydrogen sulfide, inorganic sulfate, taurine, Coenzyme A, and albumin. By optimising inorganic sulfate availability, and therefore sulfation, it is proposed that COVID-19 can be prevented or at least most of the symptoms attenuated. A comprehensive COVID-19 treatment protocol is needed to preserve the glycocalyx in both the prevention and treatment of COVID-19. The use of NAC at a dosage of 600 mg bid for the prevention of COVID-19 is proposed, but a higher dosage of NAC (1200 mg bid) should be administered upon the first onset of symptoms. In the severe to critically ill, it is advised that IV NAC should be administered immediately upon hospital admission, and in the late stage of the disease, IV sodium thiosulfate should be considered. Doxycycline as a protease inhibitor will prevent shedding and further degradation of the glycocalyx.

The Possible Role of Glucose-6-Phosphate Dehydrogenase in the SARS-CoV-2 Infection

Glucose-6-phosphate dehydrogenase (G6PD) is the second rate-limiting enzyme of the pentose phosphate pathway. This enzyme is present in the cytoplasm of all mammalian cells, and its activity is essential for an adequate functioning of the antioxidant system and for the response of innate immunity. It is responsible for the production of nicotinamide adenine dinucleotide phosphate (NADPH), the first redox equivalent, in the pentose phosphate pathway. Viral infections such as SARS-CoV-2 may induce the Warburg effect with an increase in anaerobic glycolysis and production of lactate. This condition ensures the success of viral replication and production of the virion. Therefore, the activity of G6PD may be increased in COVID-19 patients raising the level of the NADPH, which is needed for the enzymatic and non-enzymatic antioxidant systems that counteract the oxidative stress caused by the cytokine storm. G6PD deficiency affects approximately 350–400 million people worldwide; therefore, it is one of the most prevalent diseases related to enzymatic deficiency worldwide. In G6PD-deficient patients exposed to SARS-CoV-2, the amount of NADPH is reduced, increasing the susceptibility for viral infection. There is loss of the redox homeostasis in them, resulting in severe pneumonia and fatal outcomes.

Evaluating the effect of Edaravone on clinical outcome of patients with severe COVID-19 admitted to ICU: a randomized clinical trial

Cytokine storm is the most prominent hallmark in patients with coronavirus disease 2019 (COVID-19) that stimulates the free radical storm, both of which induce an overactive immune response during viral infection. We hypothesized that owning to its radical-scavenging and anti-inflammatory properties, Edaravone could reduce multi-organ injury, clinical complications, and mortality in severe COVID-19 cases. This single-center randomized clinical trial was accompanied in the intensive care units (ICUs) of the teaching hospital of Tabriz University of Medical Sciences to evaluate the effect of Edaravone on the outcome of patients with severe COVID-19. Thirty-eight patients admitted to ICU were included and randomized into two control and intervention arms. Patients in the intervention group received 30 mg Edaravone by slow intravenous infusion for three days in addition to receiving national therapy. The primary outcome was the need for intubation, the intubation length, and mortality rate. Secondary endpoints were clinical improvement. Edaravone administration improved the primary outcomes; it decreased the need for endotracheal intubation and mechanical ventilation [10.52% (n = 2) versus 42.1% (n = 8); p = 0.03] and intubation length [3 (1–7) versus 28 (4–28), p = 0.04] compared to control group. Baseline characteristics and laboratory tests were similar between the studied groups. No marked differences were observed in secondary endpoints (p > 0.05). Administration of Edaravone could decrease the need for mechanical ventilation and length of intubation in severe COVID-19 patients admitted to ICU.

Reactive Sulfur Compounds in the Fight against COVID-19

The SARS-CoV-2 coronavirus pandemic outbreak in 2019 resulted in the need to search for an effective and safe strategy for treating infected patients, relieving symptoms, and preventing severe disease. SARS-CoV-2 is an RNA virus that can cause acute respiratory failure and thrombosis, as well as impair circulatory system function. Permanent damage to the heart muscle or other cardiovascular disorders may occur during or after the infection. The severe course of the disease is associated with the release of large amounts of pro-inflammatory cytokines. Due to their documented anti-inflammatory, antioxidant, and antiviral effects, reactive sulfur compounds, including hydrogen sulfide (H₂S), lipoic acid (LA), N-acetylcysteine (NAC), glutathione (GSH), and some other lesser-known sulfur compounds, have attracted the interest of scientists for the treatment and prevention of the adverse effects of diseases caused by SARS-CoV-2. This article reviews current knowledge about various endogenous or exogenous reactive sulfur compounds and discusses the possibility, or in some cases the results, of their use in the treatment or prophylaxis of COVID-19.

COVID-19 in G6PD-deficient patients, oxidative stress, and neuropathology

Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme that regulates energy metabolism mainly through the pentose phosphate pathway (PPP). It is well known that this enzyme participates in the antioxidant/oxidant balance via the synthesis of energy-rich molecules: nicotinamide adenine dinucleotide phosphate reduced (NADPH), the reduced form of flavin adenine dinucleotide (FADH) and glutathione (GSH), controlling reactive oxygen species generation. Coronavirus disease 19 (COVID-19), induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is considered a public health problem which has caused approximately 4.5 million deaths since December 2019. In relation to the role of G6PD in COVID-19 development, it is known from the existing literature that G6PD-deficient patients infected with SARS-CoV-2 are more susceptible to thrombosis and hemolysis, suggesting that G6PD deficiency facilitates infection by SARS-CoV-2. In relation to G6PD and neuropathology, it has been observed that deficiency of this enzyme is also present with an increase in oxidative markers. In relation to the role of G6PD and the neurological manifestations of COVID-19, it has been reported that the enzymatic deficiency in patients infected with SARS-CoV-2 exacerbates the disease, and, in some clinical reports, an increase in hemolysis and thrombosis was observed when patients were treated with hydroxychloroquine (OH-CQ), a drug with oxidative properties. In the present work, we summarize the evidence of the role of G6PD in COVID-19 and its possible role in the generation of oxidative stress and glucose metabolism deficits and inflammation present in this respiratory disease and its progression including neurological manifestations.

A Network-Biology led Computational Drug repurposing Strategy to prioritize therapeutic options for COVID-19

The alarming pandemic situation of novel Severe Acute Respiratory Syndrome Coronavirus 2 (nSARS-CoV-2) infection, high drug development cost and slow process of drug discovery have made repositioning of existing drugs for therapeutics a popular alternative. It involves the repurposing of existing safe compounds which results in low overall development costs and shorter development timeline. In the present study, a computational network-biology approach has been used for comparing three candidate drugs i.e. quercetin, N-acetyl cysteine (NAC), and 2-deoxy-glucose (2-DG) to be effectively repurposed against COVID-19. For this, the associations between these drugs and genes of Severe Acute Respiratory Syndrome (SARS) and the Middle East Respiratory Syndrome (MERS) diseases were retrieved and a directed drug-gene-gene-disease interaction network was constructed. Further, to quantify the associations between a target gene and a disease gene, the shortest paths from the target gene to the disease genes were identified. A vector DV was calculated to represent the extent to which a disease gene was influenced by these drugs. Quercetin was quantified as the best among the three drugs, suited for repurposing with DV of -70.19, followed by NAC with DV of -39.99 and 2-DG with DV of -13.71. The drugs were also assessed for their safety and efficacy balance (in terms of therapeutic index) using network properties. It was found that quercetin was a forerunner than other two drugs.

Intravenous N-Acetylcysteine in Management of COVID-19: A Case Series

A novel coronavirus, severe acute respiratory syndrome coronavirus-2, was isolated from patients’ lower respiratory tracts in December 2019. As of May 19, 2021, there were over 33 million reported infections and almost 600,000 deaths in the United States. The infection, coronavirus disease-19 (COVID-19), can lead to cytokine storm, with elevations in interleukin-6 (IL-6), IL-10, tumor necrosis factor-α, nuclear factor-kappaB (NF-kappaB), and glutathione reductase. NF-kappaB activation is necessary for further transcription of other pro-inflammatory markers. Glutathione may play a role in modulation of NF-kappaB activation and elevated glutathione reductase may indicate glutathione depletion. Administration of N-acetylcysteine (NAC) may replenish spent glutathione and attenuate over-activation of NF-kappaB. This retrospective case series included 10 patients who were COVID-19 positive and received intravenous NAC in an attempt to attenuate the cytokine storm. Patients’ outcomes were graded based on the World Health Organization symptom severity scale from 0, no evidence of infection, to 8, death. Overall, the median WHO Scale prior to NAC was 6.5, and increased by day seven, which indicated clinical worsening. This retrospective case series showed no benefit of NAC; however, further studies are needed to elucidate if differences in drug regimens would lead to positive results.

N-Acetyl-L-Cysteine Protects Organ Function After Hemorrhagic Shock Combined With Seawater Immersion in Rats by Correcting Coagulopathy and Acidosis

Background

The mortality of trauma combined with seawater immersion is higher than that of land injury, however, research on how to treat this critical case and which treatments to adopt is lacking.

Methods

The effect of the thiol compound, N-acetyl-L-Cysteine (NAC), on survival, acidosis, coagulopathy, vital signs, oxidative stress, and mitochondrial and multi-organ function was assessed in a rat model of hemorrhagic shock combined with seawater immersion (Sea-Shock).

Results

Hemorrhagic shock combined with seawater immersion caused a severe lethal triad: multi-organ impairment, oxidative stress, and mitochondrial dysfunction. NAC (30 mg/kg) with lactated Ringer’s (LR) solution (2 × blood volume lost) significantly improved outcomes compared to LR or hetastarch (HES 130/0.4) alone. NAC significantly prolonged survival time to 52.48 ± 30.09 h and increased 72 h survival rate to 11/16 (68%). NAC relieved metabolic acidosis and recovered the pH back to 7.33. NAC also restored coagulation, with APTT, PT, and PT-INR decreased by 109.31, 78.09, and 73.74%, respectively, while fibrinogen level increased 246.23% compared with untreated Sea-Shock. Administration of NAC markedly improved cardiac and liver function, with some improvement of kidney function.

Conclusion

The addition of NAC to crystalloid resuscitation fluid alleviated oxidative stress, restored redox homeostasis, and provided multi-organ protection in the rats after Sea-Shock. NAC may be an effective therapeutic measure for hemorrhagic shock combined with seawater immersion.

The function of SARS-CoV-2 spike protein is impaired by disulfide-bond disruption with mutation at cysteine-488 and by thiol-reactive N-acetyl-cysteine and glutathione

Viral spike proteins play important roles in the viral entry process, facilitating attachment to cellular receptors and fusion of the viral envelope with the cell membrane. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein binds to the cellular receptor angiotensin converting enzyme-2 (ACE2) via its receptor-binding domain (RBD). The cysteine residue at position 488, consisting of a disulfide bridge with cysteine 480 is located in an important structural loop at ACE2-binding surface of RBD, and is highly conserved among SARS-related coronaviruses. We showed that the substitution of Cys-488 with alanine impaired pseudotyped SARS-CoV-2 infection, syncytium formation, and cell-cell fusion triggered by SARS-CoV-2 spike expression. Consistently, in vitro binding of RBD and ACE2, spike-mediated cell-cell fusion, and pseudotyped viral infection of VeroE6/TMPRSS2 cells were inhibited by the thiol-reactive compounds N-acetylcysteine (NAC) and a reduced form of glutathione (GSH). Furthermore, we demonstrated that the activity of variant spikes from the SARS-CoV-2 alpha and delta strains were also suppressed by NAC and GSH. Taken together, these data indicate that Cys-488 in spike RBD is required for SARS-CoV-2 spike functions and infectivity, and could be a target of anti-SARS-CoV-2 therapeutics.

COVID-19, Oxidative Stress and Male Reproduction: Possible Role of Antioxidants

Coronavirus disease 2019 (COVID-19) involves a complex pathogenesis and with the evolving novel variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the long-term impacts of the unceasing COVID-19 pandemic are mostly uncertain. Evidence indicates deleterious impact of this disease upon male reproductive health. It is concerning that COVID-19 may contribute to the already global declining trend of male fertility. The adverse impacts of COVID-19 on male reproduction may primarily be attributed to the induction of systemic inflammatory responses and oxidative stress (OS), which operate as a vicious loop. Bringing the systemic inflammation to a halt is critical for ‘putting out’ the ‘cytokine storm’ induced by excessive reactive oxygen species (ROS) generation. The possibility of OS playing a prime role in COVID-19-mediated male reproductive dysfunctions has led to the advocacy of antioxidant therapy. An array of antioxidant defense medications has shown to be effective in experimental and clinical studies of COVID-19. The present review thus discusses the possibilities as to whether antioxidant drugs would contribute to combating the SARS-CoV-2 infection-induced male reproductive disruptions, thereby aiming at kindling research ideas that are needed for identification and treatment of COVID-19-mediated male reproductive impairments.

Hyperglycemia and Loss of Redox Homeostasis in COVID-19 Patients

The infection with SARS-CoV-2 impairs the glucose−insulin axis and this contributes to oxidative (OS) and nitrosative (NSS) stress. Here, we evaluated changes in glucose metabolism that could promote the loss of redox homeostasis in COVID-19 patients. This was comparative cohort and analytical study that compared COVID-19 patients and healthy subjects. The study population consisted of 61 COVID-19 patients with and without comorbidities and 25 healthy subjects (HS). In all subjects the plasma glucose, insulin, 8-isoprostane, Vitamin D, H2S and 3-nitrotyrosine were determined by ELISA. The nitrites (NO2−), lipid-peroxidation (LPO), total-antioxidant-capacity (TAC), thiols, glutathione (GSH) and selenium (Se) were determined by spectrophotometry. The glucose, insulin and HOMA-IR (p < 0.001), 8-isoprostanes, 3-nitrotyrosine (p < 0.001) and LPO were increased (p = 0.02) while Vitamin D (p = 0.01), H2S, thiols, TAC, GSH and Se (p < 0.001) decreased in COVID-19 patients in comparison to HS. The SARS-CoV-2 infection resulted in alterations in the glucose−insulin axis that led to hyperglycemia, hyperinsulinemia and IR in patients with and without comorbidities. These alterations increase OS and NSS reflected in increases or decreases in some oxidative markers in plasma with major impact or fatal consequences in patients that course with metabolic syndrome. Moreover, subjects without comorbidities could have long-term alterations in the redox homeostasis after infection.

Use of N-Acetylcysteine at high doses as an oral treatment for patients hospitalized with COVID-19

Infection by SARS-CoV-2 causing coronavirus disease 2019 (COVID-19) can be associated with serious and life-threatening conditions, including acute respiratory distress syndrome (ARDS). Severity and mortality have been related to a cytokine storm, an imbalance of oxidative stress, and a pro-thrombotic state.

We conducted an observational retrospective cohort study from a community-based large population of hospitalized COVID-19 PCR + patients admitted from March 01, 2020, to January 24, 2021, with integrated primary to tertiary care information in Castilla la Mancha, Spain. We explored the potential benefits of the antioxidant, anti-inflammatory and anti-thrombotic drug N-acetylcysteine (NAC) administered orally in high doses (600 mg every 8 h), added to standard of care in COVID-19 patients by using the free text information contained in their electronic health records (EHRs).

Out of 19,208 patients with a diagnosis of COVID-19 hospitalized, we studied 2071 (10.8%) users of oral NAC at high doses. COVID-19 patients treated with NAC were older, predominantly male, and with more comorbidities such as hypertension, dyslipidemia, diabetes, and COPD when compared with those not on NAC (all p < 0.05). Despite greater baseline risk, use of NAC in COVID-19 patients was associated with significantly lower mortality (OR 0.56; 95%CI 0.47–0.67), a finding that remained significant in a multivariate analysis adjusting by baseline characteristics and concomitant use of corticosteroids. There were no significant differences with the use of NAC on the mean duration of hospitalization, admission to the intensive care unit or use of invasive mechanical ventilation. The observed association signaling to better relevant outcomes in COVID-19 patients treated with NAC at high doses should be further explored in other settings and populations and in randomized controlled trials.

The emerging therapeutic role of some pharmacological antidotes in management of COVID-19

Background

A novel RNA coronavirus was identified in January 2020 as the cause of a pneumonia epidemic affecting the city of Wuhan; it rapidly spread across China.

Aim of the review

The aim is to discuss the potential efficacy of some pharmacologically known pharmacological antidotes (N-acetylcysteine; hyperbaric oxygen; deferoxamine; low-dose naloxone) for the management of COVID-19-associated symptoms and complications.

Method

An extensive search was accomplished in Medline, Embase, Scopus, Web of Science, and Central databases until the end of April, 2021. Four independent researchers completed the screening, and finally, the associated studies were involved.

Conclusion

The current proof hinders the experts for suggesting the proper pharmacological lines of treatment of COVID-19. Organizations, for example, WHO, should pursue more practical actions and design well-planned clinical trials so that their results may be used in the treatment of future outbreaks.

Redox Homeostasis and Immune Alterations in Coronavirus Disease-19

The global Coronavirus Disease 2019 (COVID-19) pandemic is characterized by a wide variety of clinical features, from no or moderate symptoms to severe illness. COVID-19 is caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that first affects the respiratory tract. Other than being limited to lungs, SARS-CoV-2 may lead to a multisystem disease that can even be durable (long COVID). The clinical spectrum of COVID-19 depends on variability in the immune regulation. Indeed, disease progression is consequent to failure in the immune regulation, characterized by an intensification of the pro-inflammatory response. Disturbance of systemic and organ-related redox balance may be a further mechanism underlying variability in COVID-19 severity. Other than being determinant for SARS-CoV-2 entry and fusion to the host cell, reactive species and redox signaling are deeply involved in the immune response. This review sums up the present knowledge on the role of redox balance in the regulation of susceptibility to SARS-CoV-2 infection and related immune response, debating the effectiveness of antioxidant compounds in the management of COVID-19.

Persistent Oxidative Stress and Inflammasome Activation in CD14highCD16- Monocytes From COVID-19 Patients

The poor outcome of the coronavirus disease-2019 (COVID-19), caused by SARS-CoV-2, is associated with systemic hyperinflammatory response and immunopathology. Although inflammasome and oxidative stress have independently been implicated in COVID-19, it is poorly understood whether these two pathways cooperatively contribute to disease severity. Herein, we found an enrichment of CD14highCD16- monocytes displaying inflammasome activation evidenced by caspase-1/ASC-speck formation in severe COVID-19 patients when compared to mild ones and healthy controls, respectively. Those cells also showed aberrant levels of mitochondrial superoxide and lipid peroxidation, both hallmarks of the oxidative stress response, which strongly correlated with caspase-1 activity. In addition, we found that NLRP3 inflammasome-derived IL-1β secretion by SARS-CoV-2-exposed monocytes in vitro was partially dependent on lipid peroxidation. Importantly, altered inflammasome and stress responses persisted after short-term patient recovery. Collectively, our findings suggest oxidative stress/NLRP3 signaling pathway as a potential target for host-directed therapy to mitigate early COVID-19 hyperinflammation and also its long-term outcomes.

Renal consequences of the novel coronavirus disease 2019 (COVID-19) and hydrogen sulfide as a potential therapy

The novel coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is a global pandemic which is primarily considered a respiratory illness. However, emerging reports show that the virus exhibits both pulmonary and extra-pulmonary manifestations in humans, with the kidney as a major extra-pulmonary target due to its abundant expression of angiotensin-converting enzyme 2 and transmembrane protease serine 2, which facilitate entry of the virus into cells. Acute kidney injury has become prevalent in COVID-19 patients without prior any history of kidney dysfunction. In addition, the virus also worsens kidney conditions and increases mortality of COVID-19 patients with pre-existing chronic kidney disease, renal cancer, diabetic nephropathy, end-stage kidney disease as well as dialysis and kidney transplant patients. In the search for antiviral agents for the treatment of COVID-19, hydrogen sulfide (H₂S), the third established member of gasotransmitter family, is emerging as a potential candidate, possessing important therapeutic properties including antiviral, anti-inflammatory, anti-thrombotic and antioxidant properties. A recent clinical study revealed higher serum H₂S levels in survivors of COVID-19 pneumonia with reduced interleukin-6 levels compared to fatal cases. In this review, we summarize the global impact of COVID-19 on kidney conditions and discuss the emerging role of H₂S as a potential COVID-19 therapy.

Friend or Foe? The Roles of Antioxidants in Acute Lung Injury

Acute lung injury (ALI) is an acute hypoxic respiratory insufficiency caused by various intra- and extra-pulmonary injury factors. The oxidative stress caused by excessive reactive oxygen species (ROS) produced in the lungs plays an important role in the pathogenesis of ALI. ROS is a "double-edged sword", which is widely involved in signal transduction and the life process of cells at a physiological concentration. However, excessive ROS can cause mitochondrial oxidative stress, leading to the occurrence of various diseases. It is well-known that antioxidants can alleviate ALI by scavenging ROS. Nevertheless, more and more studies found that antioxidants have no significant effect on severe organ injury, and may even aggravate organ injury and reduce the survival rate of patients. Our study introduces the application of antioxidants in ALI, and explore the mechanisms of antioxidants failure in various diseases including it.

Pathogenesis of COVID-19 described through the lens of an undersulfated and degraded epithelial and endothelial glycocalyx

The glycocalyx surrounds every eukaryotic cell and is a complex mesh of proteins and carbohydrates. It consists of proteoglycans with glycosaminoglycan side chains, which are highly sulfated under normal physiological conditions. The degree of sulfation and the position of the sulfate groups mainly determine biological function. The intact highly sulfated glycocalyx of the epithelium may repel severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) through electrostatic forces. However, if the glycocalyx is undersulfated and 3-O-sulfotransferase 3B (3OST-3B) is overexpressed, as is the case during chronic inflammatory conditions, SARS-CoV-2 entry may be facilitated by the glycocalyx. The degree of sulfation and position of the sulfate groups will also affect functions such as immune modulation, the inflammatory response, vascular permeability and tone, coagulation, mediation of sheer stress, and protection against oxidative stress. The rate-limiting factor to sulfation is the availability of inorganic sulfate. Various genetic and epigenetic factors will affect sulfur metabolism and inorganic sulfate availability, such as various dietary factors, and exposure to drugs, environmental toxins, and biotoxins, which will deplete inorganic sulfate. The role that undersulfation plays in the various comorbid conditions that predispose to coronavirus disease 2019 (COVID-19), is also considered. The undersulfated glycocalyx may not only increase susceptibility to SARS-CoV-2 infection, but would also result in a hyperinflammatory response, vascular permeability, and shedding of the glycocalyx components, giving rise to a procoagulant and antifibrinolytic state and eventual multiple organ failure. These symptoms relate to a diagnosis of systemic septic shock seen in almost all COVID-19 deaths. The focus of prevention and treatment protocols proposed is the preservation of epithelial and endothelial glycocalyx integrity.

Impact of N-acetyl-l-cysteine on SARS-CoV-2 pneumonia and its sequelae: results from a large cohort study

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may cause pneumonia and acute respiratory distress syndrome (ARDS), whose pathogenesis has been partially related to an increased systemic inflammatory response with great production of pro-inflammatory cytokines causing a “cytokine storm” and an oxidative stress imbalance [1].

Patients receiving N-acetyl-l-cysteine (NAC) during hospitalisation for #SARSCoV2 pneumonia and discharged alive present a significantly shorter length of hospital stay compared to those who did not receive NAChttps://bit.ly/3l1QsVo

COVID-related fibrosis: insights into potential drug targets

INTRODUCTION

Lung injury in severe COVID-19 pneumonia can rapidly evolve to established pulmonary fibrosis, with prognostic implications in the acute phase of the disease and long-lasting impact on the quality of life of COVID-19 survivors. This is an emerging medical need, and it has been hypothesized that antifibrotic treatments could have a role in ameliorating the fibrotic process in the lungs of these patients.

AREAS COVERED

The safety and efficacy of available antifibrotic drugs (nintedanib and pirfenidone) and novel promising agents are being assessed in several ongoing clinical trials that were performed either in critically ill patients admitted to intensive care, or in discharged patients presenting fibrotic sequalae from COVID-19. Literature search was performed using Medline and Clinicaltrials.org databases (2001-2021).

EXPERT OPINION

Despite the strong rationale support the use of antifibrotic therapies in COVID-related fibrosis, there are several uncertainties regarding the timing for their introduction and the real risks/benefits ratio of antifibrotic treatment in the acute and the chronic phases of the disease. The findings of ongoing clinical trials and the long-term observation of longitudinal cohorts will eventually clarify the best management approach for these patients.