Mesna (2-mercaptoethane sodium sulfonate) functions as a regulator of myeloperoxidase

Mesna Improves Outcomes of Sulfur Mustard Inhalation Toxicity in an Acute Rat Model

Inhalation of high levels of sulfur mustard (SM), a potent vesicating and alkylating agent used in chemical warfare, results in acutely lethal pulmonary damage. Sodium 2-mercaptoethane sulfonate (mesna) is an organosulfur compound that is currently Food and Drug Administration (FDA)-approved for decreasing the toxicity of mustard-derived chemotherapeutic alkylating agents like ifosfamide and cyclophosphamide. The nucleophilic thiol of mesna is a suitable reactant for the neutralization of the electrophilic group of toxic mustard intermediates. In a rat model of SM inhalation, treatment with mesna (three doses: 300 mg/kg intraperitoneally 20 minutes, 4 hours, and 8 hours postexposure) afforded 74% survival at 48 hours, compared with 0% survival at less than 17 hours in the untreated and vehicle-treated control groups. Protection from cardiopulmonary failure by mesna was demonstrated by improved peripheral oxygen saturation and increased heart rate through 48 hours. Additionally, mesna normalized arterial pH and pACO2 Airway fibrin cast formation was decreased by more than 66% in the mesna-treated group at 9 hour after exposure compared with the vehicle group. Finally, analysis of mixtures of a mustard agent and mesna by a 5,5'-dithiobis(2-nitrobenzoic acid) assay and high performance liquid chromatography tandem mass spectrometry demonstrate a direct reaction between the compounds. This study provides evidence that mesna is an efficacious, inexpensive, FDA-approved candidate antidote for SM exposure. SIGNIFICANCE STATEMENT: Despite the use of sulfur mustard (SM) as a chemical weapon for over 100 years, an ideal drug candidate for treatment after real-world exposure situations has not yet been identified. Utilizing a uniformly lethal animal model, the results of the present study demonstrate that sodium 2-mercaptoethane sulfonate is a promising candidate for repurposing as an antidote, decreasing airway obstruction and improving pulmonary gas exchange, tissue oxygen delivery, and survival following high level SM inhalation exposure, and warrants further consideration.

MESNA (2-Mercaptoethanesulfonate) Attenuates Brain, Heart, and Lung Injury Induced by Carotid Ischemia-Reperfusion in Rats

Background

Ischemia-reperfusion (I/R) causes organ dysfunction as a result of the increased formation of various reactive oxygen metabolites, infiltration of inflammatory cells, interstitial edema, cellular dysfunction, and tissue death.

Aim

The study aimed to investigate the cytoprotective effect of 2-mercaptoethanesulfonate (MESNA) against tissue damage in rats exposed to carotid ischemia-reperfusion.

Materials and Methods

Twenty-four male Wistar albino rats were divided into four groups (n = 6): sham, carotid I/R, I/R + MESNA (75 mg/kg), and I/R + MESNA (150 mg/kg) groups. To induce ischemia in rats, the carotid arteries were ligated with silk sutures for 10 min; the silk suture was then opened, and 1 h reperfusion was done. MESNA (75 and 150 mg/kg) was administered intraperitoneally 30 min before ischemia-reperfusion. Tissue samples from the animals were taken for histological examination, while the serum levels of some biochemical parameters were utilized to evaluate the systemic alterations. ANOVA and Tukey's post hoc tests were applied with a significance level of 5%.

Results

The ischemia-reperfusion-induced tissue damage as evidenced by increase in serum levels of alanine transaminase, aspartate aminotransferase, alkaline phosphatase, malondialdehyde, lactate dehydrogenase, and matrix metalloproteinases (MMP-1, -2, -8) was significantly (P < 0.05-0.0001) reversed after treatment with MESNA in a dose-dependent manner. Treatment with MESNA (75 and 150 mg/kg), significantly (P < 0.05-0.0001) decreased the I/R-induced increase in serum tumor necrosis factor-alpha (TNF-α) and Interleukin-1-beta (IL-1 β).

Conclusion

The results of this study suggest that MESNA has a protective effect on tissues by suppressing cellular responses to oxidants and inflammatory mediators associated with carotid ischemia-reperfusion.

Exploring antiviral and anti-inflammatory effects of thiol drugs in COVID-19

The redox status of the cysteine-rich SARS-CoV-2 spike glycoprotein (SARS-2-S) is important for the binding of SARS-2-S to angiotensin-converting enzyme 2 (ACE2), suggesting that drugs with a functional thiol group (“thiol drugs”) may cleave cystines to disrupt SARS-CoV-2 cell entry. In addition, neutrophil-induced oxidative stress is a mechanism of COVID-19 lung injury, and the antioxidant and anti-inflammatory properties of thiol drugs, especially cysteamine, may limit this injury. To first explore the antiviral effects of thiol drugs in COVID-19, we used an ACE-2 binding assay and cell entry assays utilizing reporter pseudoviruses and authentic SARS-CoV-2 viruses. We found that multiple thiol drugs inhibit SARS-2-S binding to ACE2 and virus infection. The most potent drugs were effective in the low millimolar range, and IC₅₀ values followed the order of their cystine cleavage rates and lower thiol pK_a values. To determine if thiol drugs have antiviral effects in vivo and to explore any anti-inflammatory effects of thiol drugs in COVID-19, we tested the effects of cysteamine delivered intraperitoneally to hamsters infected with SARS-CoV-2. Cysteamine did not decrease lung viral infection, but it significantly decreased lung neutrophilic inflammation and alveolar hemorrhage. We speculate that the concentration of cysteamine achieved in the lungs with intraperitoneal delivery was insufficient for antiviral effects but sufficient for anti-inflammatory effects. We conclude that thiol drugs decrease SARS-CoV-2 lung inflammation and injury, and we provide rationale for future studies to test if direct (aerosol) delivery of thiol drugs to the airways might also result in antiviral effects.

The Role of Organosulfur Compounds as Nrf2 Activators and Their Antioxidant Effects

Nuclear factor erythroid 2-related factor 2 (Nrf2) signaling has become a key pathway for cellular regulation against oxidative stress and inflammation, and therefore an attractive therapeutic target. Several organosulfur compounds are reportedly activators of the Nrf2 pathway. Organosulfur compounds constitute an important class of therapeutic agents in medicinal chemistry due to their ability to participate in biosynthesis, metabolism, cellular functions, and protection of cells from oxidative damage. Sulfur has distinctive chemical properties such as a large number of oxidation states and versatility of reactions that promote fundamental biological reactions and redox biochemistry. The presence of sulfur is responsible for the peculiar features of organosulfur compounds which have been utilized against oxidative stress-mediated diseases. Nrf2 activation being a key therapeutic strategy for oxidative stress is closely tied to sulfur-based chemistry since the ability of compounds to react with sulfhydryl (-SH) groups is a common property of Nrf2 inducers. Although some individual organosulfur compounds have been reported as Nrf2 activators, there are no papers with a collective analysis of these Nrf2-activating organosulfur compounds which may help to broaden the knowledge of their therapeutic potentials and motivate further research. In line with this fact, for the first time, this review article provides collective and comprehensive information on Nrf2-activating organosulfur compounds and their therapeutic effects against oxidative stress, thereby enriching the chemical and pharmacological diversity of Nrf2 activators.

Thiol drugs decrease SARS-CoV-2 lung injury in vivo and disrupt SARS-CoV-2 spike complex binding to ACE2 in vitro

Neutrophil-induced oxidative stress is a mechanism of lung injury in COVID-19, and drugs with a functional thiol group (“thiol drugs”), especially cysteamine, have anti-oxidant and anti-inflammatory properties that could limit this injury. Thiol drugs may also alter the redox status of the cysteine-rich SARS-CoV-2 spike glycoprotein (SARS-2-S) and thereby disrupt ACE2 binding. Using ACE2 binding assay, reporter virus pseudotyped with SARS-CoV-2 spikes (ancestral and variants) and authentic SARS-CoV-2 (Wuhan-1), we find that multiple thiol drugs inhibit SARS-2-S binding to ACE2 and virus entry into cells. Pseudoviruses carrying variant spikes were less efficiently inhibited as compared to pseudotypes bearing an ancestral spike, but the most potent drugs still inhibited the Delta variant in the low millimolar range. IC50 values followed the order of their cystine cleavage rates and lower thiol pKa values. In hamsters infected with SARS-CoV-2, intraperitoneal (IP) cysteamine decreased neutrophilic inflammation and alveolar hemorrhage in the lungs but did not decrease viral infection, most likely because IP delivery could not achieve millimolar concentrations in the airways. These data show that thiol drugs inhibit SARS-CoV-2 infection in vitro and reduce SARS-CoV-2-related lung injury in vivo and provide strong rationale for trials of systemically delivered thiol drugs as COVID-19 treatments. We propose that antiviral effects of thiol drugs in vivo will require delivery directly to the airways to ensure millimolar drug concentrations and that thiol drugs with lower thiol pKa values are most likely to be effective.

The effect of cysteamine to decrease SARS-CoV-2 pneumonia in vivo and of multiple thiol drugs to inhibit SARS-CoV-2 infection in vitro provides rationale for clinical trials of thiol drugs in COVID-19.

Investigation of Ifosfamide Toxicity Induces Common Upstream Regulator in Liver and Kidney

Ifosfamide is an alkylating agent, a synthetic analogue of cyclophosphamide, used to treat various solid cancers. In this study, the toxicity of ifosfamide was evaluated using single-and multiple-dose intraperitoneal administration in rats under Good Laboratory Practice guidelines, and an additional microarray experiment was followed to support toxicological findings. A single dose of ifosfamide (50 mg/kg) did not induce any pathological changes. Meanwhile, severe renal toxicity was observed in the 7 and 28 days consecutively administered groups, with significant increases in blood urea nitrogen and creatinine levels. In the tox-list analysis, cholesterol synthesis-related genes were mostly affected in the liver and renal failure-related genes were affected in the kidney after ifosfamide administration. Moreover, interferon regulatory factor 7 was selected as the main upstream regulator that changed in both the liver and kidney, and was found to interact with other target genes, such as ubiquitin specific peptidase 18, radical S-adenosyl methionine domain containing 2, and interferon-stimulated gene 15, which was further confirmed by real-time RT-PCR analysis. In conclusion, we confirmed kidney-biased ifosfamide organ toxicity and identified identically altered genes in both the liver and kidney. Further comprehensive toxicogenomic studies are required to reveal the exact relationship between ifosfamide-induced genes and organ toxicity.

Mesna ameliorates acute lung injury induced by intestinal ischemia-reperfusion in rats

The lung is severely affected by intestinal ischemia-reperfusion (I-R) injury. Mesna, a thiol compound, possess anti-inflammatory and antioxidant properties. We aimed in the present work to explore the potential beneficial effects of Mesna on the acute lung damage mediated by intestinal I-R in a rat model. Forty male adult albino rats were randomly separated into; control, intestinal I-R, Mesna I and Mesna II groups. Mesna was administered by intraperitoneal injection at a dose of 100 mg/kg, 60 min before ischemia (Mesna I) and after reperfusion (Mesna II). Arterial blood gases and total proteins in bronchoalveolar lavage (BAL) were measured. Lung tissue homogenates were utilized for biochemical assays of proinflammatory cytokines and oxidative stress markers. Lung specimens were managed for examination by light and electron microscopy. Our results revealed that Mesna attenuated the histopathological changes and apoptosis of the lung following intestinal I-R. Mesna also recovered systemic oxygenation. Mesna suppressed neutrophil infiltration (as endorsed by the reduction in MPO level), reduced ICAM-1 mRNA expression, inhibited NF-κB pathway and reduced the proinflammatory cytokines (TNF-α, IL-1β and IL-6) in the lung tissues. Mesna maintained the antioxidant profile as evidenced by the elevation of the tissue GPx and SOD and down-regulation of HSP70 immune-expressions. Accordingly, Mesna treatment can be a promising way to counteract remote injury of the lung resulted from intestinal I-R.

Doxorubicin-Induced Cognitive Impairment: The Mechanistic Insights

Chemotherapy can significantly prolong the survival of patients with breast cancer; Nevertheless, the majority of patients receiving chemotherapy such as doxorubicin may have cognitive deficits that manifest as impairments in learning, reasoning, attention, and memory. The phenomenon of chemotherapy-induced cognitive decline is termed as chemotherapy-related cognitive impairment (CRCI) or chemo-brain. Doxorubicin (DOX), a commonly used drug in adjuvant chemotherapy for patients with breast cancer, has been reported to induce chemo-brain through a variety of mechanisms including DNA damage, oxidative stress, inflammation, dysregulation of apoptosis and autophagy, changes in neurotransmitter levels, mitochondrial dysfunction, glial cell interactions, neurogenesis inhibition, and epigenetic factors. These mechanisms do not operate independently but are inter-related, coordinately contributing to the development of chemo-brain. Here we review the relationships of these mechanisms and pathways in attempt to provide mechanistic insights into the doxorubicin-induced cognitive impairment.

Inhibition of Myeloperoxidase

Myeloperoxidase participates in innate immune defense mechanism through formation of microbicidal reactive oxidants and diffusible radical species. A unique activity is its ability to use chloride as a cosubstrate with hydrogen peroxide to generate chlorinating oxidants such as hypochlorous acid, a potent antimicrobial agent. However, chronic MPO activation can lead to indiscriminate protein modification causing tissue damage, and has been associated with chronic inflammatory diseases, atherosclerosis, and acute cardiovascular events. This has attracted considerable interest in the development of therapeutically useful MPO inhibitors. Today, based on the profound knowledge of structure and function of MPO and its biochemical and biophysical differences with the other homologous human peroxidases, various rational and high-throughput screening attempts were performed in developing specific irreversible and reversible inhibitors. The most prominent candidates as well as MPO inhibitors already studied in clinical trials are introduced and discussed.

Mesna Alleviates Cerulein-Induced Acute Pancreatitis by Inhibiting the Inflammatory Response and Oxidative Stress in Experimental Rats

BACKGROUND

Acute pancreatitis (AP) is a sudden inflammation of the pancreas that may be life-threatening disease with high mortality rates, particularly in the presence of systemic inflammatory response and multiple organ failure. Oxidative stress has been shown to be involved in the pathophysiology of acute pancreatitis.

AIM

This study is designed to investigate the possible effect of mesna on an experimental model of cerulein-induced acute pancreatitis.

METHODS

Animals were divided into five groups: Group 1 served as a control group given the saline; group II (mesna group) received mesna at a dose of (100 mg/kg per dose, i.p.) four times; group III (acute pancreatitis group) received cerulein at a dose of (20 µg/kg/dose, s.c.) four times with 1-h intervals; group VI, cerulein + mesna, was treated with mesna at a dose of (100 mg/kg, i.p.) 15 min before each cerulein injection.

RESULTS

Animals with acute pancreatitis showed elevated serum amylase and lipase levels. Biochemical parameters showed increased pancreatic tumor necrosis factors-α (TNF-α) and interleukin-1β (IL-1β) levels. A disturbance in oxidative stress markers was evident by elevated pancreatic lipid peroxides (TBARS) and decline in pancreatic antioxidants' concentrations including reduced glutathione (GSH); superoxide dismutase (SOD); and glutathione peroxidase (GSH-Px). Histological examination confirmed pancreatic injury. Pre-treatment with mesna was able to abolish the changes in pancreatic enzymes, oxidative stress markers (TBARS, SOD, GSH and GSH-Px), pancreatic inflammatory markers (TNF-α, IL-1β) as well as histological changes.

CONCLUSIONS

Mesna mitigates AP by alleviating pancreatic oxidative stress damage and inhibiting inflammation.

Doxorubicin and cisplatin induced cognitive impairment: The possible mechanisms and interventions

Chemotherapy has significantly increased the number of cancer survivors. However, chemotherapy itself carries various adverse effects that limit the efficacy of treatment and quality of life of the cancer patients. Most patients who have received chemotherapy report some cognitive deficit characterized by dysfunction in memory, learning, concentration, and reasoning. The phenomenon of cognitive decline developed from chemotherapy treatment is referred to as chemotherapy-induced cognitive impairment (CICI) or chemobrain. The two most common cancers occurring worldwide are lung and breast cancer. The predominant chemotherapeutic drugs used to treat lung and breast cancer are doxorubicin and cisplatin. There is evidence to suggest that both drugs potentially induce chemobrain. The evidence around the proposed pathogenesis of chemobrain caused by these two drugs is inconsistent. Understanding the underlying mechanisms involved in the development of chemobrain would aid in the prevention or treatment of the adverse effects of chemotherapy on brain. This review will summarize and discuss controversial findings and possible mechanisms involved in the development of chemobrain and the interventions which could limit it from in vitro, in vivo, and clinical studies.

The inhibition of lactoperoxidase catalytic activity through mesna (2-mercaptoethane sodium sulfonate)

Here, we show that mesna (sodium-2-mercaptoethane sulfonate), primarily used to prevent nephrotoxicity and urinary tract toxicity caused by chemotherapeutic agents such as cyclophosphamide and ifosfamide, modulates the catalytic activity of lactoperoxidase (LPO) by binding tightly to the enzyme, functioning either as a one electron substrate for LPO Compounds I and II, destabilizing Compound III. Lactoperoxidase is a hemoprotein that utilizes hydrogen peroxide (H₂O₂) and thiocyanate (SCN^-) to produce hypothiocyanous acid (HOSCN), an antimicrobial agent also thought to be associated with carcinogenesis. Our results revealed that mesna binds stably to LPO within the SCN^- binding site, dependent of the heme iron moiety, and its combination with LPO-Fe(III) is associated with a disturbance in the water molecule network in the heme cavity. At low concentrations, mesna accelerated the formation and decay of LPO compound II via its ability to serve as a one electron substrate for LPO compounds I and II. At higher concentrations, mesna also accelerated the formation of Compound II but it decays to LPO-Fe(III) directly or through the formation of an intermediate, Compound I*, that displays characteristic spectrum similar to that of LPO Compound I. Mesna inhibits LPO's halogenation activity (IC₅₀ value of 9.08 μM) by switching the reaction from a 2e^- to a 1e^- pathway, allowing the enzyme to function with significant peroxidase activity (conversion of H₂O₂ to H₂O without generation of HOSCN). Collectively, mesna interaction with LPO may serve as a potential mechanism for modulating its steady-state catalysis, impacting the regulation of local inflammatory and infectious events.

A novel gold-nanocluster-based fluorescent sensor for detection of sodium 2-mercaptoethanesulfonate

Gold nanoclusters (Au NCs) are widely used in various types of detections due to their unique fluorescence properties. However, there are rare reports on enhanced fluorescence sensors for drug molecules. Here, we report a novel strategy for detection of sodium 2-mercaptoethanesulfonate (MES) by using a fluorescence-enhanced histidine stabilized Au NCs (His-Au NCs) probe. This fluorescence probe showed excellent selectivity and sensitivity towards MES. Furthermore, we have demonstrated that the fluorescence enhancement of His-Au NCs was attributed to ligand exchange with MES by Fourier Transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The feasibility of practical applications of this probe was further investigated by sensing the MES content in Mesna injection (Uromitexan).