Unraveling Hematotoxicity of α-Amanitin in Cultured Hematopoietic Cells.

Amanita phalloides poisonings account for the majority of fatal mushroom poisonings. Recently, we identified hematotoxicity as a relevant aspect of Amanita poisonings. In this study, we investigated the effects of the main toxins of Amanita phalloides, α- and ß-amanitin, on hematopoietic cell viability in vitro. Hematopoietic cell lines were exposed to α-amanitin or ß-amanitin for up to 72 h with or without the pan-caspase inhibitor Z-VAD(OH)-FMK, antidotes N-acetylcysteine, silibinin, and benzylpenicillin, and organic anion-transporting polypeptide 1B3 (OATP1B3) inhibitors rifampicin and cyclosporin. Cell viability was established by trypan blue exclusion, annexin V staining, and a MTS assay. Caspase-3/7 activity was determined with Caspase-Glo assay, and cleaved caspase-3 was quantified by Western analysis. Cell number and colony-forming units were quantified after exposure to α-amanitin in primary CD34+ hematopoietic stem cells. In all cell lines, α-amanitin concentration-dependently decreased viability and mitochondrial activity. ß-Amanitin was less toxic, but still significantly reduced viability. α-Amanitin increased caspase-3/7 activity by 2.8-fold and cleaved caspase-3 by 2.3-fold. Z-VAD(OH)-FMK significantly reduced α-amanitin-induced toxicity. In CD34+ stem cells, α-amanitin decreased the number of colonies and cells. The antidotes and OATP1B3 inhibitors did not reverse α-amanitin-induced toxicity. In conclusion, α-amanitin induces apoptosis in hematopoietic cells via a caspase-dependent mechanism.

Lack of mitochondrial Cyp2E1 drives acetaminophen-induced ER stress-mediated apoptosis in mouse and human kidneys: Inhibition by 4-methylpyrazole but not N-acetylcysteine.

Acetaminophen (APAP) overdose causes liver injury and acute liver failure, as well as acute kidney injury, which is not prevented by the clinical antidote N-acetyl-L-cysteine (NAC). The absence of therapeutics targeting APAP-induced nephrotoxicity is due to gaps in understanding the mechanisms of renal injury. APAP metabolism through Cyp2E1 drives cell death in both the liver and kidney. We demonstrate that Cyp2E1 is localized to the proximal tubular cells in mouse and human kidneys. Virtually all the Cyp2E1 in kidney cells is in the endoplasmic reticulum (ER), not in mitochondria. By contrast, hepatic Cyp2E1 is in both the ER and mitochondria of hepatocytes. Consistent with this subcellular localization, a dose of 600 mg/kg APAP in fasted C57BL/6J mice induced the formation of APAP protein adducts predominantly in mitochondria of hepatocytes, but the ER of the proximal tubular cells of the kidney. We found that reactive metabolite formation triggered ER stress-mediated activation of caspase-12 and apoptotic cell death in the kidney. While co-treatment with 4-methylpyrazole (4MP; fomepizole) or the caspase inhibitor Ac-DEVD-CHO prevented APAP-induced cleavage of procaspase-12 and apoptosis in the kidney, treatment with NAC had no effect. These mechanisms are clinically relevant because 4MP but not NAC also significantly attenuated APAP-induced apoptotic cell death in primary human kidney cells. We conclude that reactive metabolite formation by Cyp2E1 in the ER results in sustained ER stress that causes activation of procaspase-12, triggering apoptosis of proximal tubular cells, and that 4MP but not NAC may be an effective antidote against APAP-induced kidney injury.

In Vitro Evaluation of Oxidative Stress Induced by Oxime Reactivators of Acetylcholinesterase in HepG2 Cells.

Oxime reactivators of acetylcholinesterase (AChE) are used as causal antidotes for intended and unintended poisoning by organophosphate nerve agents and pesticides. Despite all efforts to develop new AChE reactivators, none of these drug candidates replaced conventional clinically used oximes. In addition to the therapeutic efficacy, determining the safety profile is crucial in preclinical drug evaluation. The exact mechanism of oxime toxicity and the structure-toxicity relationship are subjects of ongoing research, with oxidative stress proposed as a possible mechanism. In the present study, we investigated four promising bispyridinium oxime AChE reactivators, K048, K074, K075, and K203, and their ability to induce oxidative stress in vitro. Cultured human hepatoma cells were exposed to oximes at concentrations corresponding to their IC50 values determined by the MTT assay after 24 h. Their potency to generate reactive oxygen species, interfere with the thiol antioxidant system, and induce lipid peroxidation was evaluated at 1, 4, and 24 h of exposure. Reactivators without a double bond in the four-carbon linker, K048 and K074, showed a greater potential to induce oxidative stress compared with K075 and K203, which contain a double bond. Unlike oximes with a three-carbon-long linker, the number of aldoxime groups attached to the pyridinium moieties does not determine the oxidative stress induction for K048, K074, K075, and K203 oximes. In conclusion, our results emphasize that the structure of oximes plays a critical role in inducing oxidative stress, and this relationship does not correlate with their cytotoxicity expressed as the IC50 value. However, it is important to note that oxidative stress cannot be disregarded as a potential contributor to the side effects associated with oximes.

Nrf2 as a therapeutic target in acetaminophen hepatotoxicity: A case study with sulforaphane.

Acetaminophen (APAP) overdose can cause severe liver injury and acute liver failure. The only clinically approved antidote, N-acetylcysteine (NAC), is highly effective but has a narrow therapeutic window. In the last 2 decades, activation of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), which regulates acute phase proteins and antioxidant defense genes, has emerged as a putative new therapeutic target against APAP hepatotoxicity. However, virtually all studies that propose Nrf2 activation as mechanism of protection used prolonged pretreatment, which is not a clinically feasible approach to treat a drug overdose. Therefore, the objective of this study was to assess if therapeutic activation of Nrf2 is a viable approach to treat liver injury after APAP overdose. We used the water-soluble Nrf2 activator sulforaphane (SFN; 5 mg/kg) in a murine model of APAP hepatotoxicity (300 mg/kg). Our results indicate that short-term treatment (≤3 h) with SFN alone did not activate Nrf2 or its target genes. However, posttreatment with SFN after APAP partially protected at 6 h likely due to more rapid activation of the Nrf2-target gene heme oxygenase-1. A direct comparison of SFN with NAC given at 1 h after APAP showed a superior protection with NAC, which was maintained at 24 h unlike with SFN. Thus, Nrf2 activators have inherent problems like the need to create a cellular stress to activate Nrf2 and delayed adaptive responses which may hamper sustained protection against APAP hepatotoxicity. Thus, compared to the more direct acting antidote NAC, Nrf2 activators are less suitable for this indication.

The vitamin B12 analog cobinamide ameliorates azide toxicity in cells, Drosophila melanogaster, and mice.

CONTEXT: The azide anion (N3-) is highly toxic. It exists most commonly as sodium azide, which is used widely and is readily available, raising the potential for occupational incidents and use as a weapon of mass destruction. Azide-poisoned patients present with vomiting, seizures, hypotension, metabolic acidosis, and coma; death can occur. No specific azide antidote exists, with treatment being solely supportive. Azide inhibits mitochondrial cytochrome c oxidase and is likely oxidized to nitric oxide in vivo. Cytochrome c oxidase inhibition depletes intracellular adenosine triphosphate and increases oxidative stress, while increased nitric oxide causes hypotension and exacerbates oxidative damage. Here, we tested whether the cobalamin (vitamin B12) analog cobinamide, a strong and versatile antioxidant that also neutralizes nitric oxide, can reverse azide toxicity in mammalian cells, Drosophila melanogaster, and mice. RESULTS: We found cobinamide bound azide with a moderate affinity (Ka 2.87 × 105 M-1). Yet, cobinamide improved growth, increased intracellular adenosine triphosphate, and reduced apoptosis and malondialdehyde, a marker of oxidative stress, in azide-exposed cells. Cobinamide rescued Drosophila melanogaster and mice from lethal exposure to azide and was more effective than hydroxocobalamin. Azide likely generated nitric oxide in the mice, as evidenced by increased serum nitrite and nitrate, and reduced blood pressure and peripheral body temperature in the animals; the reduced temperature was likely due to reflex vasoconstriction in response to the hypotension. Cobinamide improved recovery of both blood pressure and body temperature. CONCLUSION: We conclude cobinamide likely acted by neutralizing both oxidative stress and nitric oxide, and that it should be given further consideration as an azide antidote.

When and How to Use Reversal Agents for Direct Oral Anticoagulants?

PURPOSE OF REVIEW: Our objective is to describe currently available reversal agents for direct oral anticoagulants (DOACs), their target population, the available clinical practice recommendations and future directions. RECENT FINDINGS: Specific (idarucizumab for dabigatran and andexanet alfa for direct factor Xa inhibitors) and non-specific (prothrombin complex concentrates) reversal agents are effective in neutralizing the anticoagulant effect of DOACs. New investigational antidotes such as ciraparantag and VMX-C001 offer an alternative to andexanet alfa in reversing the anticoagulant activity of direct oral factor Xa inhibitors, but more clinical data are needed before they could be licensed for use. Specific reversal agents are recommended for use in clinical situations within their licensed indications (i.e.: reversal of DOACs in patients with severe uncontrolled or life-threatening bleeding or in need of emergency surgery or other invasive procedures), while non-specific reversal agents may be used when specific antidotes are not available or indicated.

Sodium bicarbonate reverts electrophysiologic cardiotoxicity of ropivacaine faster than lipid emulsions in a porcine model.

Ropivacaine has been described as a safer local anaesthetic (LA); however, serious cardiotoxic accidents have been reported. Intravenous-lipid-emulsion (ILE) therapy during LA intoxication seems to act as an antidote. Sodium bicarbonate is the standard treatment for sodium channel blocker drug toxicity. We compared both antidotes on the reversion of electrophysiologic toxicity induced by ropivacaine. Ropivacaine 5 mg kg-1 was administered in 24 pigs, and 3 min later, the animals received ILE: 1.5 ml kg-1  + 0.25 ml kg-1  min-1 (ILE group); sodium bicarbonate: 2 mEq kg-1  + 1 mEq kg-1  h-1 (NaHCO3 group); saline solution (CTL group). Electrophysiological parameters were evaluated for 30 min. The area under the curve (AUC) for the first 5 or 30 min was compared between groups. Ropivacaine induced a lengthening of the PR interval by 17% (P = 0.0001), His-ventricle-interval by 58% (P = 0.001), sinus QRS complex by 56% (P = 0.0001), paced QRS at 150 bpm by 257% (P = 0.0001), and at 120 bpm by 143% (P = 0.0001) in all groups. At 5 min after treatment, sinus QRS in the NaHCO3 group was shorter than that in the CTL group (AUCQRS5 , P = 0.003) or ILE group (AUCQRS5 , P = 0.045). During the first minute, seven of the animals in the NaHCO3 group vs. two in the ILE or 0 in the CTL group recovered more than 30% of the sinus QRS previously lengthened by ropivacaine (P = 0.003). Sodium bicarbonate reversed the electrophysiological toxicity of ropivacaine faster than ILE and control groups.

Progress on the detoxification of aflatoxin B1 using natural anti-oxidants.

Aflatoxins are toxic secondary metabolites produced by Aspergillus fungi. The most toxic among them is Aflatoxin B1 (AFB1) which is known to have genotoxic, immunotoxic, teratogenic, carcinogenic, and mutagenic toxic effects (amongst others). The mechanisms responsible for its toxicity include the induction of oxidative stress, cytotoxicity, and DNAdamage. Studies have found that natural anti-oxidants can reduce the damage that AFB1 inflicts on the body by alleviating oxidative stress and inhibiting the biotransformation of AFB1. Therefore, this review outlines the latest progress in research on the use of natural anti-oxidants as antidotes to aflatoxin poisoning and their detoxification mechanisms. It also considers the problems that may possibly arise from their use and their application prospects. Our aim is to provide a useful reference for the prevention and treatment of AFB1 poisoning.

Spatiotemporally Targeted Polypeptide Nanoantidotes Improve Chemotherapy Tolerance of Cisplatin.

The toxicity of drugs causes various adverse effects in patients. While antidotes that neutralize drug toxicity help reduce systemic damage during clinical therapy, these antidotes are generally accompanied by the loss of drug efficacy. Herein, the spatiotemporally targeted polycystine-based nanoantidotes were designed as a neutralizer of cisplatin (CDDP) to decrease its toxicity without affecting its anticancer efficacy. The nanoantidotes administered before CDDP selectively accumulated in the liver and kidney and then firmly bound to CDDP through the highly stable Pt-S bond during subsequent chemotherapy. This two-step administration strategy reduced the level of Pt in normal organs, shortened the half-life of CDDP in plasma, and increased the tolerance to CDDP. More importantly, the nanoantidotes maintained the anticancer efficacy of CDDP after reducing systemic toxicity, indicating its great potential in expanding the clinical application of CDDP.

A non-canonical vitamin K cycle is a potent ferroptosis suppressor.

Ferroptosis, a non-apoptotic form of cell death marked by iron-dependent lipid peroxidation1, has a key role in organ injury, degenerative disease and vulnerability of therapy-resistant cancers2. Although substantial progress has been made in understanding the molecular processes relevant to ferroptosis, additional cell-extrinsic and cell-intrinsic processes that determine cell sensitivity toward ferroptosis remain unknown. Here we show that the fully reduced forms of vitamin K-a group of naphthoquinones that includes menaquinone and phylloquinone3-confer a strong anti-ferroptotic function, in addition to the conventional function linked to blood clotting by acting as a cofactor for γ-glutamyl carboxylase. Ferroptosis suppressor protein 1 (FSP1), a NAD(P)H-ubiquinone reductase and the second mainstay of ferroptosis control after glutathione peroxidase-44,5, was found to efficiently reduce vitamin K to its hydroquinone, a potent radical-trapping antioxidant and inhibitor of (phospho)lipid peroxidation. The FSP1-mediated reduction of vitamin K was also responsible for the antidotal effect of vitamin K against warfarin poisoning. It follows that FSP1 is the enzyme mediating warfarin-resistant vitamin K reduction in the canonical vitamin K cycle6. The FSP1-dependent non-canonical vitamin K cycle can act to protect cells against detrimental lipid peroxidation and ferroptosis.

The Therapeutic Potential of Carnosine as an Antidote against Drug-Induced Cardiotoxicity and Neurotoxicity: Focus on Nrf2 Pathway.

Different drug classes such as antineoplastic drugs (anthracyclines, cyclophosphamide, 5-fluorouracil, taxanes, tyrosine kinase inhibitors), antiretroviral drugs, antipsychotic, and immunosuppressant drugs are known to induce cardiotoxic and neurotoxic effects. Recent studies have demonstrated that the impairment of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway is a primary event in the pathophysiology of drug-induced cardiotoxicity and neurotoxicity. The Nrf2 pathway regulates the expression of different genes whose products are involved in antioxidant and inflammatory responses and the detoxification of toxic species. Cardiotoxic drugs, such as the anthracycline doxorubicin, or neurotoxic drugs, such as paclitaxel, suppress or impair the Nrf2 pathway, whereas the rescue of this pathway counteracts both the oxidative stress and inflammation that are related to drug-induced cardiotoxicity and neurotoxicity. Therefore Nrf2 represents a novel pharmacological target to develop new antidotes in the field of clinical toxicology. Interestingly, carnosine (ß-alanyl-l-histidine), an endogenous dipeptide that is characterized by strong antioxidant, anti-inflammatory, and neuroprotective properties is able to rescue/activate the Nrf2 pathway, as demonstrated by different preclinical studies and preliminary clinical evidence. Starting from these new data, in the present review, we examined the evidence on the therapeutic potential of carnosine as an endogenous antidote that is able to rescue the Nrf2 pathway and then counteract drug-induced cardiotoxicity and neurotoxicity.

Antidotal effect of cyclosporine A against α-amanitin toxicity in CD-1 mice, at clinical relevant doses.

Amanita phalloides is one of the most toxic mushrooms worldwide, being responsible for the majority of human fatal cases of mushroom intoxications. α-Amanitin, the most deleterious toxin of A. phalloides, inhibits RNA polymerase II (RNAP II), causing hepatic and renal failure. Herein, we used cyclosporine A after it showed potential to displace RNAP II α-amanitin in silico. That potential was not confirmed either by the incorporation of ethynyl-UTP or by the monitoring of fluorescent RNAP II levels. Nevertheless, concomitant incubation of cyclosporine A with α-amanitin, for a short period, provided significant protection against its toxicity in differentiated HepaRG cells. In mice, the concomitant administration of α-amanitin [0.45 mg/kg intraperitoneal (i.p.)] with cyclosporine A (10 mg/kg i.p. plus 2 × 10 mg/kg cyclosporine A i.p. at 8 and 12 h post α-amanitin) resulted in the full survival of α-amanitin-intoxicated mice, up to 30 days after the toxin's administration. Since α-amanitin is a substrate of the organic-anion-transporting polypeptide 1B3 and cyclosporine A inhibits this transporter and is a potent anti-inflammatory agent, we hypothesize that these mechanisms are responsible for the protection observed. These results indicate a potential antidotal effect of cyclosporine A, and its safety profile advocates for its use at an early stage of α-amanitin intoxications.

Neonicotinoids: mechanisms of systemic toxicity based on oxidative stress-mitochondrial damage.

Neonicotinoids are the most widely used pesticides in the world. However, research studies have shown that it can affect the cognitive abilities and health of non-target bees and other wild pollinators by inducing DNA damage, apoptosis and mitochondrial damage, injure to its central nervous system, and it is even developmentally neurotoxic to mammals and humans, with mitochondria being an important target of neonicotinoids. Therefore, this article reviews the role of mitochondrial morphology, calcium ions (Ca2+) homeostasis, respiratory function, apoptosis, and DNA damage in neonicotinoids-induced systemic toxicity. Additionally, it evaluates the protective effects of various active substances including vitamin C, N-acetylcysteine (NAC), curcumin (CUR), glutathione reduced (GSH), caffeic acid phenethyl ester (CAPE), resveratrol, and thymoquinone (TQ) on neonicotinoids-induced toxicity. This review manuscript found that mitochondria are important targets to neonicotinoids. Neonicotinoids can cause DNA damage, apoptosis, protein oxidation, and lipid peroxidation in non-target organisms by altering mitochondrial Ca2+ homeostasis, inhibiting mitochondrial respiration, and inducing reactive oxygen species (ROS) production. Several active substances (vitamin C, NAC, CUR, GSH, resveratrol, CAPE, and TQ) play a protective role against neonicotinoid-induced systemic toxicity by inhibiting ROS signaling pathways, apoptosis, and lipid peroxidation. This review manuscript emphasizes the importance and urgency of the development of neonicotinoid antidotes, emphasizes the prospect of the application of targeted mitochondrial antidotes, and prospects the development of neonicotinoid antidotes in order to provide some strategies for the prevention of neonicotinoid toxicity.

Dynamic Combinatorial Optimization of In Vitro and In Vivo Heparin Antidotes.

Heparin-like macromolecules are widely used in clinics as anticoagulant, antiviral, and anticancer drugs. However, the search of heparin antidotes based on small synthetic molecules to control blood coagulation still remains a challenging task due to the physicochemical properties of this anionic polysaccharide. Here, we use a dynamic combinatorial chemistry approach to optimize heparin binders with submicromolar affinity. The recognition of heparin by the most amplified members of the dynamic library has been studied with different experimental (SPR, fluorescence, NMR) and theoretical approaches, rendering a detailed interaction model. The enzymatic assays with selected library members confirm the correlation between the dynamic covalent screening and the in vitro heparin inhibition. Moreover, both ex vivo and in vivo blood coagulation assays with mice show that the optimized molecules are potent antidotes with potential use as heparin reversal drugs. Overall, these results underscore the power of dynamic combinatorial chemistry targeting complex and elusive biopolymers.

Comparing N-acetylcysteine and 4-methylpyrazole as antidotes for acetaminophen overdose.

Acetaminophen (APAP) overdose can cause hepatotoxicity and even liver failure. N-acetylcysteine (NAC) is still the only FDA-approved antidote against APAP overdose 40 years after its introduction. The standard oral or intravenous dosing regimen of NAC is highly effective for patients with moderate overdoses who present within 8 h of APAP ingestion. However, for late-presenting patients or after ingestion of very large overdoses, the efficacy of NAC is diminished. Thus, additional antidotes with an extended therapeutic window may be needed for these patients. Fomepizole (4-methylpyrazole), a clinically approved antidote against methanol and ethylene glycol poisoning, recently emerged as a promising candidate. In animal studies, fomepizole effectively prevented APAP-induced liver injury by inhibiting Cyp2E1 when treated early, and by inhibiting c-jun N-terminal kinase (JNK) and oxidant stress when treated after the metabolism phase. In addition, fomepizole treatment, unlike NAC, prevented APAP-induced kidney damage and promoted hepatic regeneration in mice. These mechanisms of protection (inhibition of Cyp2E1 and JNK) and an extended efficacy compared to NAC could be verified in primary human hepatocytes. Furthermore, the formation of oxidative metabolites was eliminated in healthy volunteers using the established treatment protocol for fomepizole in toxic alcohol and ethylene glycol poisoning. These mechanistic findings, together with the excellent safety profile after methanol and ethylene glycol poisoning and after an APAP overdose, suggest that fomepizole may be a promising antidote against APAP overdose that could be useful as adjunct treatment to NAC. Clinical trials to support this hypothesis are warranted.

Cytotoxicity-related effects of imidazolium and chlorinated bispyridinium oximes in SH-SY5Y cells.

Current research has shown that several imidazolium and chlorinated bispyridinium oximes are cytotoxic and activate different mechanisms or types of cell death. To investigate this further, we analysed interactions between these oximes and acetylcholine receptors (AChRs) and how they affect several signalling pathways to find a relation between the observed toxicities and their effects on these specific targets. Chlorinated bispyridinium oximes caused time-dependent cytotoxicity by inhibiting the phosphorylation of STAT3 and AMPK without decreasing ATP and activated ERK1/2 and p38 MAPK signal cascades. Imidazolium oximes induced a time-independent and significant decrease in ATP and inhibition of the ERK1/2 signalling pathway along with phosphorylation of p38 MAPK, AMPK, and ACC. These pathways are usually triggered by a change in cellular energy status or by external signals, which suggests that oximes interact with some membrane receptors. Interestingly, in silico analysis also indicated that the highest probability of interaction for all of our oximes is with the family of G-coupled membrane receptors (GPCR). Furthermore, our experimental results showed that the tested oximes acted as acetylcholine antagonists for membrane AChRs. Even though oxime interactions with membrane receptors need further research and clarification, our findings suggest that these oximes make promising candidates for the development of specific therapies not only in the field of cholinesterase research but in other fields too, such as anticancer therapy via altering the Ca2+ flux involved in cancer progression.

Evaluation of aqueous dimethyl trisulfide as an antidote to a highly lethal cyanide poisoning in a large swine model.

BACKGROUND: Cyanide is a rapid acting, lethal, metabolic poison and remains a significant threat. Current FDA-approved antidotes are not amenable or efficient enough for a mass casualty incident. OBJECTIVE: The objective of this study is to evaluate short and long-term efficacy of intramuscular aqueous dimethyl trisulfide (DMTS) on survival and clinical outcomes in a swine model of cyanide exposure. METHODS: Anesthetized swine were instrumented and acclimated until breathing spontaneously. Potassium cyanide infusion was initiated and continued until 5 min after the onset of apnea. Subsequently, animals were treated with intramuscular DMTS (n = 11) or saline control (n = 10). Laboratory values and DMTS blood concentrations were assessed at various time points and physiological parameters were monitored continuously until the end of the experiment unless death occurred. A subset of animals treated with DMTS (n = 5) were survived for 7 days to evaluate muscle integrity by repeat biopsy and neurobehavioral outcomes. RESULTS: Physiological parameters and time to apnea were similar in both groups at baseline and at time of treatment. Survival in the DMTS-treated group was 90% and 30% in saline controls (p = 0.0034). DMTS-treated animals returned to breathing at 12.0 ± 10.4 min (mean ± SD) compared to 22.9 ± 7.0 min (mean ± SD) in the 3 surviving controls. Blood collected prior to euthanasia showed improved blood lactate concentrations in the DMTS treatment group; 5.47 ± 2.65 mmol/L vs. 9.39 ± 4.51 mmol/L (mean ± SD) in controls (p = 0.0310). Low concentrations of DMTS were detected in the blood, gradually increasing over time with no elimination phase observed. There was no mortality, histological evidence of muscle trauma, or observed adverse neurobehavioral outcomes, in DMTS-treated animals survived to 7 days. CONCLUSION: Intramuscular administration of aqueous DMTS improves survival following cyanide poisoning with no observed long-term effects on muscle integrity at the injection site or adverse neurobehavioral outcomes.

Delayed administration of N-acetylcysteine blunts recovery after an acetaminophen overdose unlike 4-methylpyrazole.

N-acetylcysteine (NAC) is the only clinically approved antidote against acetaminophen (APAP) hepatotoxicity. Despite its efficacy in patients treated early after APAP overdose, NAC has been implicated in impairing liver recovery in mice. More recently, 4-methylpyrazole (4MP, Fomepizole) emerged as a potential antidote in the mouse APAP hepatotoxicity model. The objective of this manuscript was to verify the detrimental effect of NAC and its potential mechanism and assess whether 4MP has the same liability. C57BL/6J mice were treated with 300 mg/kg APAP; 9 h after APAP and every 12 h after that, the animals received either 100 mg/kg NAC or 184.5 mg/kg 4MP. At 24 or 48 h after APAP, parameters of liver injury, mitochondrial biogenesis and cell proliferation were evaluated. Delayed NAC treatment had no effect on APAP-induced liver injury at 24 h but reduced the decline of plasma ALT activities and prevented the shrinkage of the areas of necrosis at 48 h. This effect correlated with down-regulation of key activators of mitochondrial biogenesis (AMPK, PGC-1α, Nrf1/2, TFAM) and reduced expression of Tom 20 (mitochondrial mass) and PCNA (cell proliferation). In contrast, 4MP attenuated liver injury at 24 h and promoted recovery at 48 h, which correlated with enhanced mitochondrial biogenesis and hepatocyte proliferation. In human hepatocytes, 4MP demonstrated higher efficacy in preventing cell death compared to NAC when treated at 18 h after APAP. Thus, due to the wider treatment window and lack of detrimental effects on recovery, it appears that at least in preclinical models, 4MP is superior to NAC as an antidote against APAP overdose.

Study of the cardioprotective effects of crocin on Human Cardiac Myocyte cells and reduction of oxidative stress produced by aluminum phosphide poisoning.

OBJECTIVES: The effects of Crocin as a cardioprotective material against Aluminum phosphide poisoning by reducing the oxidative stress is investigated. METHODS: The level of biomarkers of oxidative stress (Catalase, Superoxide dismutase, Malondialdehyde and Protein carbonyl) were measured in the cell culture model on Human Cardiac Myocyte cells to detect the protective effect of crocin. Initially, to define the pure impact of aluminum phosphide poison and crocin on the heart cells, their effects on the biomarkers quantity in cell line were measured, separately, using the standard related kits. Later the effect of crocin with different concentration as a treatment on the oxidative stress biomarkers of the poisoned heart cells were monitored. Note that in pre-treatment case, the crocin was initially added to the cells before poisoning them. Data were analyzed using the analysis of variance method. KEY FINDINGS: Results showed that crocin treatment reduced the aluminum phosphide (AlP) poisoning effect significantly. The treatment resulted in substantial deviation in the biomarkers of oxidative stress at the pre- and post-treatment phases for all groups. The oxidative markers values of the poisoned cells were recovered by crocin treatment. CONCLUSIONS: Crocin is proposed as a potentially powerful antioxidant to treat the cardiotoxicity caused by aluminum phosphide poisoning.

Toxic effects of chlorine gas and potential treatments: a literature review.

Chlorine gas is one of the highly produced chemicals in the USA and around the world. Chlorine gas has several uses in water purification, sanitation, and industrial applications; however, it is a toxic inhalation hazard agent. Inhalation of chlorine gas, based on the concentration and duration of the exposure, causes a spectrum of symptoms, including but not limited to lacrimation, rhinorrhea, bronchospasm, cough, dyspnea, acute lung injury, death, and survivors develop signs of pulmonary fibrosis and reactive airway disease. Despite the use of chlorine gas as a chemical warfare agent since World War I and its known potential as an industrial hazard, there is no specific antidote. The resurgence of the use of chlorine gas as a chemical warfare agent in recent years has brought speculation of its use as weapons of mass destruction. Therefore, developing antidotes for chlorine gas-induced lung injuries remains the need of the hour. While some of the pre-clinical studies have made substantial progress in the understanding of chlorine gas-induced pulmonary pathophysiology and identifying potential medical countermeasure(s), yet none of the drug candidates are approved by the U.S. Food and Drug Administration (FDA). In this review, we summarized pathophysiology of chlorine gas-induced pulmonary injuries, pre-clinical animal models, development of a pipeline of potential medical countermeasures under FDA animal rule, and future directions for the development of antidotes for chlorine gas-induced lung injuries.