Medical management of paraquat ingestion

Fractionated plasma separation and adsorption integrated with continuous veno-venous hemofiltration in patients with acute bipyridine herbicide poisoning

OBJECTIVE

To evaluate the clinical efficacy and safety of fractionated plasma separation and adsorption combined with continuous veno-venous hemofiltration (FPSA-CVVH) treatment in patients with acute bipyridine herbicide poisoning.

METHODS

A retrospective analysis of 18 patients with acute bipyridine herbicide poisoning was conducted, of which 9 patients were poisoned by diquat and 9 patients by paraquat. All patients underwent FPSA-CVVH treatment. The serum cytokine levels in pesticide-poisoned patients were assessed. The efficacy of FPSA-CVVH in eliminating cytokines, the 90-d survival rate of poisoned patients, and adverse reactions to the treatment were observed.

RESULTS

Fourteen patients (77.8%) had acute kidney injuries and 10 (55.6%) had acute liver injuries. The serum cytokine levels of high mobility group protein B-1 (HMGB-1), interleukin-6 (IL-6), IL-8, interferon-inducible protein-10 (IP-10), monocyte chemotactic protein-1 (MCP-1), and macrophage inflammatory protein-1β (MIP-1β) were significantly elevated. A total of 41 FPSA-CVVH treatment sessions were administered. After a single 8-h FPSA-CVVH treatment, the decreases in HMGB-1, IL-6, IL-8, IP-10, MCP-1, and MIP-1β were 66.0%, 63.5%, 73.3%, 63.7%, 53.9%, and 54.1%, respectively. During FPSA-CVVH treatment, one patient required a filter change due to coagulation in the plasma component separator, and one experienced a bleeding adverse reaction. The 90-d patient survival rate was 50%, with 4 patients with diquat poisoning and 5 patients with paraquat poisoning, and both liver and kidney functions were restored to normal.

CONCLUSION

Cytokine storms may play a significant role in the progression of multiorgan dysfunction in patients with acute bipyridine herbicide poisoning. FPSA-CVVH can effectively reduce cytokine levels, increase the survival rate of patients with acute bipyridine herbicide poisoning, and decrease the incidence of adverse events.

Schistosoma japonicum cystatin alleviates paraquat poisoning caused acute lung injury in mice through activating regulatory macrophages

BACKGROUND

Paraquat (PQ) is a widely used herbicide that poisons human by accident or intentional ingestion. PQ poisoning causes systemic inflammatory response syndrome (SIRS) resulting in acute lung injury (ALI) with an extremely high mortality rate. Blood trematode Schistosoma japonicum-produced cystatin (Sj-Cys) is a strong immunomodulatory protein that has been experimentally used to treat inflammation related diseases. In this study, Sj-Cys recombinant protein (rSj-Cys) was used to treat PQ-induced lung injury and the immunological mechanism underlying the therapeutic effect was investigated.

METHODS

PQ-induced acute lung injury mouse model was established by intraperitoneally injection of 20 mg/kg of paraquat. The poisoned mice were treated with rSj-Cys and the survival rate was observed up to 7 days compared with the group without treatment. The pathological changes of PQ-induced lung injury were observed by examining the histochemical sections of affected lung tissue and the wet to dry ratio of lung as a parameter for inflammation and edema. The levels of the inflammation related cytokines IL-6 and TNF-α and regulatory cytokines IL-10 and TGF-β were measured in sera and in affected lung tissue using ELISA and their mRNA levels in lung tissue using RT-PCR. The macrophages expressing iNOS were determined as M1 and those expressing Arg-1 as M2 macrophages. The effect of rSj-Cys on the transformation of inflammatory M1 to regulatory M2 macrophages was measured in affected lung tissue in vivo (EKISA and RT-PCR) and in MH-S cell line in vitro (flow cytometry). The expression levels of TLR2 and MyD88 in affected lung tissue were also measured to determine their role in the therapy of rSj-Cys on PQ-induced lung injury.

RESULT

We identified that treatment with rSj-Cys significantly improved the survival rate of mice with PQ-induced lung injury from 30 % (untreated) to 80 %, reduced the pathological damage of poisoning lung tissue, associated with significantly reduced levels of proinflammatory cytokines (IL-6 from 1490 to 590 pg/ml, TNF-α from 260 to 150 pg/ml) and increased regulatory cytokines (IL-10 from360 to 550 pg/ml, and TGF-β from 220 to 410 pg/ml) in both sera (proteins) and affected lung tissue (proteins and mRNAs). The polarization of macrophages from M1to M2 type was found to be involved in the therapeutic effect of rSj-Cys on the PQ-induced acute lung injury, possibly through inhibiting TLR2/MyD88 signaling pathway.

CONCLUSIONS

Our study demonstrated the therapeutic effect of rSj-Cys on PQ poisoning caused acute lung injury by inducing M2 macrophage polarization through inhibiting TLR2/MyD88 signaling pathway. The finding in this study provides an alternative approach for the treatment of PQ poisoning and other inflammatory diseases.

YAP/TAZ activation mediates PQ-induced lung fibrosis by sustaining senescent pulmonary epithelial cells

Paraquat (PQ) is a widely used herbicide and a common cause of poisoning that leads to pulmonary fibrosis with a high mortality rate. However, the underlying mechanisms of PQ-induced pulmonary fibrosis and whether pulmonary epithelial cell senescence is involved in the process remain elusive. In this study, PQ-induced pulmonary epithelial cell senescence and Hippo-YAP/TAZ activation were observed in both C57BL/6 mice and human epithelial cells. PQ-induced senescent pulmonary epithelial cells promoted lung fibroblast transformation through secreting senescence-associated secretory phenotype (SASP) factors. Yap/Taz knockdown in mice lungs significantly decreased the expression of downstream profibrotic protein Ctgf and senescent markers p16 and p21, and alleviated PQ-induced pulmonary fibrosis. Interfering YAP/TAZ in senescent human pulmonary epithelial cells resulted in decreased expression of the anti-apoptosis protein survivin and elevated level of apoptosis. In conclusion, our findings reveal a novel mechanism by which the involvement of Hippo-YAP/TAZ activation in pulmonary epithelial cell senescence mediates the pathogenesis of PQ-induced pulmonary fibrosis, thereby offering novel insights and potential targets for the clinical management of PQ poisoning as well as providing the mechanistic insight of the involvement of Yap/Taz activation in cell senescence in pulmonary fibrosis and its related pulmonary disorders. The YIN YANG balance between cell senescence and apoptosis is important to maintain the homeostasis of the lung, the disruption of which will lead to disease.

Utility of Clinical Variables for Deciding Palliative Care in Paraquat Poisoning: A Retrospective Study

Background

Patients with paraquat poisoning (PP) have a mortality rate comparable to that of advanced malignancies, yet palliative care is seldom considered in these patients. This audit aimed to identify triggers for early palliative care referral in critically ill patients with PP.

Methods

Medical records of patients with PP were audited. Predictors of mortality within 48 hours of hospitalization and 24 hours of intensive care unit (ICU) admission were considered as triggers for palliative care referral.

Results

Among 108 patients, 84 complete records were analyzed, and 53 out of 84 (63.1%) expired. Within 48 hours after hospitalization, the lowest oxygen partial pressure in arterial blood to a fraction of inspired oxygen [the ratio of partial pressure of oxygen in arterial blood (PaO2) to the fraction of inspiratory oxygen concentration (FiO2) (PaO2/FiO2)] was the independent predictor of mortality, cut-off ≤ 197; the area under the curve (AUC), 0.924; sensitivity, 97%; specificity, 78%; p <0.001; and 95% confidence interval (CI): 0.878-0.978. Kaplan-Meier survival plot showed that the mean survival time of patients with the lowest PaO2/FiO2, ≤197, was 4.64 days vs 17.20 days with PaO2/FiO2 >197 (log-rank p < 0.001). Sequential organ failure assessment (SOFA) score within 24 hours of ICU admission had a cut-off ≥9; AUC, 0.980; p < 0.001; 95% CI: 0.955-1.000; 91% sensitivity; and 90% specificity for mortality prediction. Out of the total of 84 patients with PP analyzed, there were 11 patients admitted to the high dependency units (13.1%) and 73 patients admitted to the ICU (86.9%). Out of the total of 84 patients of PP in whom data was analyzed, 53 (63.1%) patients required ventilator support. All the 53 patients who required ventilator support due to worsening hypoxemia, eventually expired.

Conclusion

The lowest PaO2/FiO2 ≤ 197 within 48 hours of hospitalization, SOFA score ≥9 within 24 hours of ICU admission or need for mechanical ventilation are predictors of mortality in PP patients, who might benefit from early palliative care.

How to cite this article

Rao S, Maddani SS, Chaudhuri S, Bhatt MT, Karanth S, Damani A, et al. Utility of Clinical Variables for Deciding Palliative Care in Paraquat Poisoning: A Retrospective Study. Indian J Crit Care Med 2024;28(5):453-460.

Nanocrocin Protective Effects on Paraquat-Induced Oxidative Stress in the MRC-5 Cell Line

Paraquat (PQ) herbicide poisoning is a severe medical problem in developing countries without suitable therapy. This study aimed to investigate the effects of crocin (CCN) and nano crocin (NCCN) on PQ -induced toxicity in the MRC-5 cell line. The results showed that the particle size of NCCN was 140.3 ± 18.0 nm, and the zeta potential of the optimal crocin-loaded niosomes was 23.4 ± 2.8 mV. The NCCN was more effective than CCN in the inhibition of PQ-induced toxicity. Treatment of the MRC-5 cells leads to a decrease in ROS and an increase in SOD, CAT, GPX, and TAC levels in PQ-CCN and PQ-NCCN groups compared with the PQ group. These changes tended to be positively associated with the NCCN compared to CCN. Overall, NCCN was more effective than crocin in treating PQ-induced toxicity in vitro and deserved further preclinical consideration.

Digital colloid-enhanced Raman spectroscopy by single-molecule counting

Quantitative detection of various molecules at very low concentrations in complex mixtures has been the main objective in many fields of science and engineering, from the detection of cancer-causing mutagens and early disease markers to environmental pollutants and bioterror agents1-5. Moreover, technologies that can detect these analytes without external labels or modifications are extremely valuable and often preferred6. In this regard, surface-enhanced Raman spectroscopy can detect molecular species in complex mixtures on the basis only of their intrinsic and unique vibrational signatures7. However, the development of surface-enhanced Raman spectroscopy for this purpose has been challenging so far because of uncontrollable signal heterogeneity and poor reproducibility at low analyte concentrations8. Here, as a proof of concept, we show that, using digital (nano)colloid-enhanced Raman spectroscopy, reproducible quantification of a broad range of target molecules at very low concentrations can be routinely achieved with single-molecule counting, limited only by the Poisson noise of the measurement process. As metallic colloidal nanoparticles that enhance these vibrational signatures, including hydroxylamine-reduced-silver colloids, can be fabricated at large scale under routine conditions, we anticipate that digital (nano)colloid-enhanced Raman spectroscopy will become the technology of choice for the reliable and ultrasensitive detection of various analytes, including those of great importance for human health.

Acute paraquat poisoning in an adolescent with compromised outcome: A case report

Paraquat, a highly toxic herbicide, accounts for a substantial number of poisoning-related fatalities, primarily prevalent in agricultural regions. The ingestion gives rise to severe complications affecting various organs, including the lungs, gastrointestinal tract, kidneys and liver. This report details the case of an 18-year-old male who had been using cannabis for a year and inadvertently ingested paraquat. He presented at the emergency room exhibiting symptoms of vomiting characterized by hematemesis and regurgitated food particles, along with heartburn, dysphagia and reduced urine output. Given the absence of a specific antidote, the prognosis for paraquat poisoning remains generally unfavourable. Diagnosis relies on circumstantial evidence and clinical manifestations, necessitating a focus on supportive care. Presently, no specific antidote for paraquat poisoning is available. Efforts should concentrate on preventive measures, efficient decontamination strategies and vigilant stabilization protocols in instances of exposure.

Exosomes from senescent epithelial cells activate pulmonary fibroblasts via the miR-217-5p/Sirt1 axis in paraquat-induced pulmonary fibrosis

BACKGROUND

Paraquat (PQ) is a widely used and highly toxic herbicide that poses a significant risk to human health. The main consequence of PQ poisoning is pulmonary fibrosis, which can result in respiratory failure and potentially death. Our research aims to uncover a crucial mechanism in which PQ poisoning induces senescence in epithelial cells, ultimately regulating the activation of pulmonary fibroblasts through the exosomal pathway.

METHODS

Cellular senescence was determined by immunohistochemistry and SA-β-Gal staining. The expression of miRNAs was measured by qPCR. Pulmonary fibroblasts treated with specific siRNA of SIRT1 or LV-SIRT1 were used to analysis senescent exosomes-mediated fibroblasts activation. Luciferase reporter assay and western blot were performed to elucidated the underlying molecular mechanisms. The effects of miR-217-5p antagomir on pulmonary fibrosis were assessed in PQ-poisoned mice models.

RESULTS

Impairing the secretion of exosomes effectively mitigates the harmful effects of senescent epithelial cells on pulmonary fibroblasts, offering protection against PQ-induced pulmonary fibrosis in mice. Additionally, we have identified a remarkable elevation of miR-217-5p expression in the exosomes of PQ-treated epithelial cells, which specifically contributes to fibroblasts activation via targeted inhibition of SIRT1, a protein involved in cellular stress response. Remarkably, suppression of miR-217-5p effectively impaired senescent epithelial cells-induced fibroblasts activation. Further investigation has revealed that miR-217-5p attenuated SIRT1 expression and subsequently resulted in enhanced acetylation of β-catenin and Wnt signaling activation.

CONCLUSION

These findings highlight a potential strategy for the treatment of pulmonary fibrosis induced by PQ poisoning. Disrupting the communication between senescent epithelial cells and pulmonary fibroblasts, particularly by targeting the miR-217-5p/SIRT1/β-catenin axis, may be able to alleviate the effects of PQ poisoning on the lungs.

Risk assessment of pesticides used in the eastern Avocado Belt of Michoacan, Mexico: A survey and water monitoring approach

Pesticides use raises concerns regarding environmental sustainability, as pesticides are closely linked to the decline of biodiversity and adverse human health outcomes. This study proposed a holistic approach for assessing the potential risks posed by pesticides for human health and the environment in the eastern region of Michoacan, where extensive agricultural lands, especially corn and avocado fields, surround the Monarch Butterfly Biosphere Reserve. We used a combination of qualitative (semi-structured interviews) and quantitative (chemical analysis) data. Fifty-five interviews with smallholder farmers allowed us to identify pesticide types, quantities, frequencies, and application methods. A robust and precise analytical method based on solid-phase extraction and LC-MS/MS was developed and validated to quantify 21 different pesticides in 16 water samples (rivers, wells, runoff areas). We assessed environmental and human health risks based on the pesticides detected in the water samples and reported in the interviews. The interviews revealed the use of 28 active ingredients, including glyphosate (29 % of respondents), imidacloprid (27 %), and benomyl (24 %). The pesticide analysis showed the presence of 13 different pesticides and degradation products in the water samples. The highest concentrations were found for imidacloprid (1195 ngL-1) and carbendazim (a degradation product of benomyl; 932 ngL-1), along with the metabolite of pyrethroid insecticides, 3-PBA (494 ngL-1). The risk assessment indicates that among the most used pesticides, the fungicide benomyl and carbendazim pose the highest risk to human health and aquatic ecosystems, respectively. This study unveils novel insights on agricultural practices for the avocado, a globally consumed crop that is undergoing rapid production expansion. It calls for the harmonisation of crop protection with environmental responsibility, safeguarding the health of the people involved and the surrounding ecosystems.

Single-cell RNA-sequencing of cellular heterogeneity and pathogenic mechanisms in paraquat-induced Parkinson's disease with depression

Parkinson's disease (PD) is among the most prevalent neurodegenerative diseases, and approximately one third of patients with PD are estimated to have depression. Paraquat (PQ) exposure is an important environmental risk factor for PD. In this study, we established a mouse model of PQ-induced PD with depression to comprehensively investigate cellular heterogeneity and the mechanisms underlying the progression of depression in the context of PD. We utilized single-cell RNA-seq (scRNA-seq) to acquire the transcriptomic atlas of individual cells from model mice and characterize the gene expression profiles in each differentially expressed cell type. We identified a specific glutamatergic neuron cluster responsible for the development of heterogeneous depression-associated changes and established a comprehensive gene expression atlas. Furthermore, functional enrichment and cell trajectory analyses revealed that the mechanisms underlying the progression of PD with depression were associated with specific glutamatergic neurons. Together, our findings provide a valuable resource for deciphering the cellular heterogeneity of PD with depression. The suggested connection between intrinsic transcriptional states of neurons and the progression of depression can provide insight into potential biomarkers and specific targets for anti-depression treatment in patients with PD. SYNOPSIS: Our results obtained using model mice confirm the core effects of PQ exposure on glutamatergic neurons and their potential role in the development of PD with depression.

Improvement of inhaled paraquat induced lung and systemic inflammation, oxidative stress and memory changes by safranal

The effects of safranal and pioglitazone alone and their combination on inhaled paraquat (PQ)-induced systemic oxidative stress and inflammation as well as behavioral changes were examined in rats. In this study, animals were exposed to saline (Ctrl) or PQ (PQ groups) aerosols. PQ exposed animals were treated with dexamethasone, 0.8 and 3.2 mg/kg/day safranal (Saf-L and Saf-H), 5 mg/kg/day pioglitazone (Pio), and Saf-L + Pio for 16 days during PQ exposure period. PQ group showed increased numbers of total and differential WBCs in blood and bronchoalveolar lavage fluid (BALF), increased malondialdehyde (MDA), in the serum BALF and brain reduced thiol, catalase (CAT), and superoxide dismutase (SOD) levels compared to the control group (for all, p < 0.001). The escape latency and traveled distance were enhanced, but the time spent in the target quadrant in the probe day and the latency to enter the dark room 3, 24, 48, and 72 h after receiving an electrical shock, (in the shuttle box test) were decreased in the PQ group (p < 0.05 to P < 0.001). In all treated groups, all measure values were improved compared to PQ group (p < 0.05 to p < 0.001). In combination treated group of Saf-L + Pio, most measured values were more improved than the Saf-L and Pio groups (p < 0.05 to p < 0.001). Saf and Pio improved PQ-induced changes similar to dexamethasone but the effects produced by combination treatments of Saf-L + Pio were more prominent than Pio and Saf-L alone, suggesting a potentiating effect for the combination of the two agents.

A Forensic Case of Suicide Ingestion of Paraquat Herbicide: New Histological Insights and Revision of the Literature

ABSTRACT

Paraquat (PQ) is one of the most widely used herbicides in the world, and poisoning is generally associated with accidental, suicidal, or homicidal events. Therefore, in the forensic context, PQ could be in various ways involved as a possible cause of death of a subject. However, even though its systemic toxicity is known, the biological effects exerted on individual viscera have been explored only to some extent, especially in case of victim's survival. Therefore, a case concerning a suicidal ingestion of PQ with survival of 3 days was deemed of interest. Clinical toxicological analyses confirmed acute PQ intoxication, and after the death of the victim, an autopsy was performed showing local and systemic signs of ingestion of a caustic substance. Histologic examination revealed marked cellular damage to the major viscera, particularly the gastroesophageal tract, liver, kidneys, and lungs, with initial alveolar fibrosis noted despite the patient's short survival. This finding represents a new element in the context of PQ lung injury, as it has not been previously documented in the literature. Thus, histological findings in lethal intoxications after survival can reveal specific peculiarities still unknown and, therefore, assume transversal relevance not only at forensic but also clinical level.

Inhaled paraquat-induced lung injury in rat, improved by the extract of Zataria multiflora boiss and PPARγ agonist, pioglitazone

The effects of a PPAR-γ agonist, pioglitazone and Zataria multiflora (Z. multiflora) on inhaled paraquat (PQ)-induced lung oxidative stress, inflammation, pathological changes and tracheal responsiveness were examined. The study was carried out in control rats exposed to normal aerosol of saline, PQl and PQh groups exposed to aerosols of 27 and 54 mg/m3 PQ, groups exposed to high PQ concentration (PQh) and treated with 200 and 800 mg/kg/day Z. multiflora, 5 and 10 mg/kg/day pioglitazone, low doses of Z. multiflora + pioglitazone, and 0.03 mg/kg/day dexamethasone. Increased tracheal responsiveness, transforming growth factor beta (TGF-ß) and lung pathological changes due to PQh were significantly improved by high doses of Z. multiflora and pioglitazone, dexamethasone and extract + pioglitazone, (p < 0.05 to p < 0.001). In group treated with low doses of the extract + pioglitazone, the improvements of most measured variables were significantly higher than the low dose of two agents alone (p < 0.05 to p < 0.001). Z. multiflora improved lung injury induced by inhaled PQ similar to dexamethasone and pioglitazone which could be mediated by PPAR-γ receptor.

Integrated analysis of ceRNA-miRNA changes in paraquat-induced pulmonary epithelial-mesenchymal transition via high-throughput sequencing

Recent studies have shown that epithelial-mesenchymal transition (EMT) plays an important role in paraquat (PQ)-induced tissue fibrosis, which is the main cause of death in patients with PQ poisoning. However, no effective treatment for pulmonary interstitial fibrosis caused by PQ poisoning exists. It is of great significance for us to find new therapeutic targets through bioinformatics in PQ-induced EMT. We conducted transcriptome sequencing to determine the expression profiles of 1210 messenger RNAs (mRNAs), 558 long noncoding RNAs, 28 microRNAs (miRNAs), including 18 known-miRNAs, 10 novel-miRNAs and 154 circular RNAs in the PQ-exposed EMT group mice. Using gene ontology and Kyoto Encyclopaedia of Genes and Genomes analyses, we identified the pathways associated with signal transduction, cancers, endocrine systems and immune systems were involved in PQ-induced EMT. Furthermore, we constructed long noncoding RNA-miRNA-mRNA interrelated networks and found that upregulated genes included Il22ra2, Mdm4, Slc35e2 and Angptl4, and downregulated genes included RGS2, Gabpb2, Acvr1, Prkd3, Sp100, Tlr12, Syt15 and Camk2d. Thirteen new potential competitive endogenous RNA targets were also identified for further treatment of PQ-induced pulmonary tissue fibrosis. Through further study of the pathway and networks, we may identify new molecular targets in PQ-induced pulmonary EMT.

Targeted inhibition of transforming growth factor-β type I receptor by AZ12601011 improves paraquat poisoning-induced multiple organ fibrosis

Paraquat (PQ) causes fatal poisoning that leads to systemic multiple organ fibrosis, and transforming growth factor (TGF)-β1 plays a critical role in this process. In this study, we aimed to investigate the effects of AZ12601011 (a small molecular inhibitor of TGFβRI) on PQ-induced multiple organ fibrosis. We established a mouse model of PQ in vivo and used PQ-treated lung epithelial cell (A549) and renal tubular epithelial cells (TECs) in vitro. Haematoxylin-eosin and Masson staining revealed that AZ12601011 ameliorated pulmonary, hepatic, and renal fibrosis, consistent with the decrease in the levels of fibrotic indicators, alpha-smooth muscle actin (α-SMA) and collagen-1, in the lungs and kidneys of PQ-treated mice. In vitro data showed that AZ12601011 suppressed the induction of α-SMA and collagen-1 in PQ-treated A549 cells and TECs. In addition, AZ12601011 inhibited the release of inflammatory factors, interleukin (IL)-1β, IL-6, and tumour necrosis factor-α. Mechanistically, TGF-β and TGFβRI levels were significantly upregulated in the lungs and kidneys of PQ-treated mice. Cellular thermal shift assay and western blotting revealed that AZ12601011 directly bound with TGFβRI and blocked the activation of Smad3 downstream. In conclusion, our findings revealed that AZ12601011 attenuated PQ-induced multiple organ fibrosis by blocking the TGF-β/Smad3 signalling pathway, suggesting its potential for PQ poisoning treatment.

Mitochondrial reactive oxygen species initiate gasdermin D-mediated pyroptosis and contribute to paraquat-induced nephrotoxicity

Paraquat (PQ)-induced acute kidney injury (AKI) progresses rapidly and is associated with high mortality rates; however, no specific antidote for PQ has been identified. Poor understanding of toxicological mechanisms underlying PQ has hindered the development of suitable treatments to combat PQ exposure. Gasdermin D (GSDMD), a key executor of pyroptosis, has recently been shown to enhance nephrotoxicity in drug-induced AKI. To explore the role of pyroptosis in PQ-induced AKI, the plasma membrane damage of the cells was detected by LDH release assay. Western blot was performed to detect the cleavage of GSDMD. RNA sequencing analysis was performed to explore the mechanism of PQ induced nephrotoxicity. Herein, we demonstrated that PQ could induce pyroptosis in HK-2 cells and nephridial tissues. Mechanistically, PQ initiated GSDMD cleavage, and GSDMD knockout attenuated PQ-induced nephrotoxicity in vivo. Further analysis revealed that the accumulation of mitochondrial reactive oxygen species (ROS) induced p38 activation, contributing to PQ-induced pyroptosis. Furthermore, mitoquinone, a mitochondria-targeted antioxidant, reduced mitochondrial ROS levels and inhibited pyroptosis. Collectively, these findings provide insights into the role of GSDMD-dependent pyroptosis as a novel mechanism of PQ-induced AKI.

Regulation of NCOA4-mediated iron recycling ameliorates paraquat-induced lung injury by inhibiting ferroptosis

Paraquat (PQ) is an irreplaceable insecticide in many countries for the advantage of fast-acting and broad-spectrum. However, PQ was classified as the most prevailing poisoning substance for suicide with no specific antidote. Therefore, it is imperative to develop more effective therapeutic agents for the treatment of PQ poisoning. In the present study, both the RNA-Seq and the application of various cell death inhibitors reflected that ferroptosis exerts a crucial regulatory role in PQ poisoning. Moreover, we found PQ strengthens lipid peroxidation as evidenced by different experimental approaches. Of note, pretreatment of iron chelation agent DFO could ameliorate the ferroptotic cell death and alleviate the ferroptosis-related events. Mechanistically, PQ treatment intensively impaired mitochondrial homeostasis, enhanced phosphorylation of AMPK, accelerated the autophagy flux and triggered the activation of Nuclear receptor coactivator 4-ferritin heavy chain (NCOA4-FTH) axis. Importantly, the activation of autophagy was observed prior to the degradation of ferritin, and inhibition of autophagy could inhibit the accumulation of iron caused by the ferritinophagy process. Genetic and pharmacological inhibition of ferritinophagy could alleviate the lethal oxidative events, and rescue the ferroptotic cell death. Excitingly, in the mouse models of PQ poisoning, both the administration of DFO and adeno-associated virus-mediated FTH overexpression significantly reduced PQ-induced ferroptosis and improved the pathological characteristics of pulmonary fibrosis. In summary, the current work provides an in-depth study on the mechanism of PQ intoxication, describes a framework for the further understanding of ferroptosis in PQ-associated biological processes, and demonstrates modulation of iron metabolism may act as a promising therapeutic agent for the management of PQ toxicity.

Development and validation of a prognostic nomogram for predicting in-hospital mortality of patients with acute paraquat poisoning

This study aimed to develop and validate a predictive model to determine the risk of in-hospital mortality in patients with acute paraquat poisoning. This retrospective observational cohort study included 724 patients with acute paraquat poisoning whose clinical data were collected within 24 h of admission. The primary outcome was in-hospital mortality. Patients were randomly divided into training and validation cohorts (7/3 ratio). In the training cohort, the least absolute shrinkage and selection operator regression models were used for data dimension reduction and feature selection. Multivariate logistic regression was used to generate a predictive nomogram for in-hospital mortality. The prediction model was assessed for both the training and validation cohorts. In the training cohort, decreased level of consciousness (Glasgow Coma Scale score < 15), neutrophil-to-lymphocyte ratio, alanine aminotransferase, creatinine, carbon dioxide combining power, and paraquat plasma concentrations at admission were identified as independent predictors of in-hospital mortality in patients with acute paraquat poisoning. The calibration curves, decision curve analysis, and clinical impact curves indicated that the model had a good predictive performance. It can be used on admission to the emergency department to predict mortality and facilitate early risk stratification and actionable measures in clinical practice after further external validation.

The Peptide DHα-(4-pentenyl)-ANPQIR-NH2 Exhibits Antifibrotic Activity in Multiple Pulmonary Fibrosis Models Induced by Particulate and Soluble Chemical Fibrogenic Agents

Interstitial lung diseases (ILDs) are a group of restrictive lung diseases characterized by interstitial inflammation and pulmonary fibrosis. The incidence of ILDs associated with exposure to multiple hazards such as inhaled particles, fibers, and ingested soluble chemicals is increasing yearly, and there are no ideal drugs currently available. Our previous research showed that the novel and low-toxicity peptide DHα-(4-pentenyl)-ANPQIR-NH2 (DR3penA) had a strong antifibrotic effect on a bleomycin-induced murine model. Based on the druggability of DR3penA, we sought to investigate its effects on respirable particulate silicon dioxide (SiO2)- and soluble chemical paraquat (PQ)-induced pulmonary fibrosis in this study by using western blot, quantitative reverse-transcription polymerase chain reaction (RT-qPCR), immunofluorescence, H&E and Masson staining, immunohistochemistry, and serum biochemical assays. The results showed that DR3penA alleviated the extent of fibrosis by inhibiting the expression of fibronectin and collagen I and suppressed oxidative stress and epithelial-mesenchymal transition (EMT) in vitro and in vivo. Further study revealed that DR3penA may mitigate pulmonary fibrosis by negatively regulating the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway and mitogen-activated protein kinase (MAPK) pathway. Unexpectedly, through the conversion of drug bioavailability under different routes of administration, DR3penA exerted antifibrotic effects equivalent to those of the positive control drug pirfenidone (PFD) at lower doses. In summary, DR3penA may be a promising lead compound for various fibrotic ILDs. SIGNIFICANCE STATEMENT: Our study verified that DHα-(4-pentenyl)-ANPQIR-NH2 (DR3penA) exhibited positive antifibrotic activity in pulmonary fibrosis induced by silicon dioxide (SiO2) particles and soluble chemical paraquat (PQ) and demonstrated a low-dose advantage compared to the small-molecule drug pirfenidone (PFD). The peptide DR3penA can be further developed for the treatment of multiple fibrotic lung diseases.

A mass event of paraquat poisoning via inhalation

Objective

In January 2023, a rare event of collective inhalation paraquat poisoning occurred in Shandong, China. To analyze the clinical characteristics of an event of respiratory tract paraquat poisoning through inhalation.

Methods

Clinical data from eight patients with paraquat inhalation poisoning were retrospectively analyzed.

Results

The patients were mainly exposed to paraquat via the respiratory tract. The main clinical manifestations were ocular and respiratory irritation. Lung computed tomography (CT) showed that all eight patients had varying degrees of lung injury, mainly manifesting as exudative lesions. Laboratory tests revealed arterial blood gas hypoxemia, abnormal white blood cell count, and increased neutrophil ratio. Sufficient glucocorticoid impact therapy was effective, and all eight patients survived.

Conclusion

Eight patients experienced chest tightness, shortness of breath, and varying degrees of lung injury due to inhalation of paraquat through the respiratory tract. The early use of glucocorticoids and other comprehensive treatment measures, active prevention and treatment of lung infections, and protection of organ function have beneficial effects in such cases.

Anti-inflammatory effect of dental pulp stem cells

Dental pulp stem cells (DPSCs) have received a lot of attention as a regenerative medicine tool with strong immunomodulatory capabilities. The excessive inflammatory response involves a variety of immune cells, cytokines, and has a considerable impact on tissue regeneration. The use of DPSCs for controlling inflammation for the purpose of treating inflammation-related diseases and autoimmune disorders such as supraspinal nerve inflammation, inflammation of the pulmonary airways, systemic lupus erythematosus, and diabetes mellitus is likely to be safer and more regenerative than traditional medicines. The mechanism of the anti-inflammatory and immunomodulatory effects of DPSCs is relatively complex, and it may be that they themselves or some of the substances they secrete regulate a variety of immune cells through inflammatory immune-related signaling pathways. Most of the current studies are still at the laboratory cellular level and animal model level, and it is believed that through the efforts of more researchers, DPSCs/SHED are expected to be transformed into excellent drugs for the clinical treatment of related diseases.

Abnormalities of serum lipid metabolism in patients with acute paraquat poisoning caused by ferroptosis

As the mechanism of paraquat (PQ) poisoning is still not fully elucidated, and no specific treatment has been developed in medical practice, the management of PQ poisoning continues to present a medical challenge. In this study, the objective was to investigate the early metabolic changes in serum metabolism and identify the key metabolic pathways involved in patients with PQ poisoning. Quantitative analysis was conducted to determine the relevant metabolites. Additionally, experiments were carried out in both plasma and cell to elucidate the mechanisms underlying metabolic disorder and cell death in PQ poisoning. The study found that polyunsaturated fatty acids (PUFAs) and their metabolites, such as arachidonic acid (AA) and hydroxy eicosatetraenoic acids (HETEs), were significantly increased by non-enzymatic oxidative reaction. Reactive oxygen species (ROS) production increased rapidly at 2 h after PQ poisoning, followed by an increase in PUFAs at 12 h, and intracellular glutathione, cysteine (Cys), and Fe2+ at 24 h. However, at 36 h later, intracellular glutathione and Cys decreased, HETEs increased, and the expression of SLC7A11 and glutathione peroxidase 4 (GPX4) decreased. Ultrastructural examination revealed the absence of mitochondrial cristae. Deferoxamine was found to alleviate lipid oxidation, and increase the viability of PQ toxic cells in the low dose. In conclusion, unsaturated fatty acids metabolism was the key metabolic pathways in PQ poisoning. PQ caused cell death through the induction of ferroptosis. Inhibition of ferroptosis could be a novel strategy for the treatment of PQ poisoning.

106 Cases of homicide poisoning in China-A retrospective study

Homicidal poisoning has received limited scholarly attention, despite having recently increased in frequency in China, especially in rural areas, where it causes numerous deaths and disabilities. In this study, the author collected data on 106 cases of homicidal poisoning from 1995 to 2000. Of these cases 105 were found through website established by the Supreme Court of China, and one case was as an exception identified from the internet. There were 46 male perpetrators and 59 female perpetrators. The most common reason male perpetrators poisoned someone was conflict among neighbours (include residents in the same village) (ten cases), and the most common reason female perpetrators did so was an affair (13 cases). Compared with the perpetrators of general homicide, those who poisoned people included a high proportion of female, elderly, and well-educated individuals. This is related to the nonviolent nature of the poisoning, which requires no physical strength. Residents living in rural and urban areas chose poisoning based on convenience. People living in rural areas used pesticides most often, and people in urban areas have greater access to drugs or medications obtained at work or online. In this study, a total of 9.4% of the perpetrators were diagnosed with psychiatric disorders or psychosis. In all, the 106 cases resulted in 58 human deaths. Tetramine and paraquat caused many of the deaths, and this suggests a need for the government to manage and monitor these highly toxic pesticides. These cases are representative of issues in contemporary Chinese society, for example, population mobility, fierce competition.

Nilotinib alleviates paraquat-induced hepatic and pulmonary injury in rats via the Nrf2/Nf-kB axis

BACKGROUND

Paraquat (PQ, 1,1'-dimethyl-4-4'-bipyridinium dichloride) is a highly toxic quaternary ammonium herbicide widely used in agriculture. It exerts its toxic effects mainly as a result of its redox cycle via the production of superoxide anions in organisms, leading to an imbalance in the redox state of the cell causing oxidative damage and finally cell death. The aim of this study was to estimate the beneficial protective role of nilotinib (NIL) on PQ-induced hepatic and pulmonary toxicity in rats.

METHODS

Male wistar rats were randomly divided into four groups, namely control, PQ (15 mg/kg), PQ plus NIL (5 mg/kg) and PQ plus NIL (10 mg/kg). NIL (5 and 10 mg/kg/day) was taken by oral syringe for five days followed by a single intra-peritoneal administration of PQ (15 mg/kg) on sixth day.

RESULTS

Pretreatment with NIL relieved the histological damage in liver and lung tissues and improved hepatic biochemical markers. It significantly (p < 0.05) reduced serum levels of ALT, AST, ALP, Y-GT and total bilirubin while increased that of albumin. Meanwhile, NIL significantly (p < 0.05) reduced oxidative stress markers via reduction of malondialdhyde (MDA) and elevation of glutathione (GSH) contents in liver and lung tissues. In addition, it significantly (p < 0.05) decreased the inflammation by reducing hepatic and pulmonary tumor necrosis factor alpha (TNF-α) and nuclear transcription factor kappa B (NF-KB/p65) contents. Nilotinib also down-regulated apoptosis by reducing cysteinyl aspartate-specific proteinase-3 (caspase-3). Furthermore, it upregulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and microtubule-associated protein 1A/1B-light chain 3 II (LC3II) in liver and lung tissues.

SIGNIFICANCE

NIL suppressed PQ-induced inflammation, oxidative stress and apoptosis in liver and lung tissues by modulating Nrf2/Nf-kB axis.

Predicting mortality in paraquat poisoning through clinical findings, with a focus on pulmonary and cardiovascular system disorders

BACKGROUND

Paraquat, one of the most widely used herbicides, poses a significant risk of mortality through self-poisoning and subsequent multiple organ failure. The primary objective aimed to identify the factors associated with death in patients poisoned by paraquat.

METHODS

A cross-sectional retrospective review was conducted at a tertiary referral hospital over five years. Eligible patients presented with acute paraquat toxicity between 1 January 2016 and 31 December 2020. Medical records of 148 patients were reviewed.

RESULTS

The in-hospital fatality rate was found to be 21.8%. Multivariate analysis revealed that the amount of paraquat ingested and clinical presentations, particularly pulmonary and cardiovascular system disorders, were significantly associated with mortality.

CONCLUSION

Our study highlights that the amount of paraquat ingested, along with the presence of pulmonary and cardiovascular system disorders, can serve as prognostic indicators for mortality rates in cases of paraquat poisoning. These findings have important implications for physicians in predicting the prognosis and mortality of paraquat poisoning patients.

Acute paraquat poisoning complicated by acute kidney injury and lung fibrosis: a case report from Nepal

Introduction and importance

While incidents are rare elsewhere, paraquat herbicide poisoning is a serious medical issue in some parts of Asia. It can cause the failure of various organs, including the heart, kidneys, liver, adrenal glands, central nervous system, muscles, and spleen. Due to its inherent toxicity and lack of available therapies, paraquat has a very high case fatality rate.

Case presentation

The authors discuss a case of a 15-year-old female with an alleged history of paraquat ingestion who presented with complaints of vomiting, abdominal pain, and loose stools. Initially, she had gastrointestinal symptoms, but she developed renal failure and respiratory symptoms and died of multiple organ failure.

Clinical discussion

Acute gastrointestinal tract necrosis and multiorgan failure are the initial effects of paraquat intake, and among those who survive the immediate post-ingestion interval, the lung is the target organ for poisoning. Ingestion of large amounts of liquid concentrates results in fulminant organ failure: pulmonary edema, cardiac, renal, and hepatic failure, and convulsions. The course of treatment can range from supportive care alone to various integration of immune modulation, antioxidant therapy, hemoperfusion, and hemodialysis.

Conclusion

Patients presenting to the emergency department with an alleged history of ingestion of paraquat poisoning should be admitted even if they have mild symptoms initially. There is no specific antidote available. Early renal failure, along with progressive pulmonary fibrosis, can lead to death.

Prognostic Value of the Average Lung CT Number in Patients with Acute Paraquat Poisoning

Objective

The chest computed tomography (CT) examination is an important clinical examination in the diagnosis and monitoring of paraquat- (PQ-) induced lung injury. The aim of this study was to explore the prognostic value of the average lung CT number acquired by quantitative CT techniques in patients with acute paraquat poisoning in the early stages of the disease.

Methods

46 patients who suffered from acute PQ poisoning in the emergency department of the Nanjing Drum Tower Hospital from January 2015 to June 2020 were enrolled in the present study. The patients were divided into survival group (n = 21) and nonsurvival group (n = 25). Clinical data were collected from subjects who met the inclusion criteria, including general information, personal disease history, and laboratory test indicators. The average lung CT numbers of each patient were obtained by quantitative CT techniques. Receiver operating characteristic (ROC) analysis was conducted to assess the prognostic value of average lung CT number in patients with acute paraquat poisoning.

Results

The average CT numbers of the middle-lung, lower-lung, and whole lung fields in the nonsurvival group were significantly higher than those of the survival group (p < 0.0001). However, the upper-lung field was not significantly different between the two groups (p = 0.7765). The AUCs of different levels ranged from 0.554 to 0.977, among which the lower-lung field presented the largest AUC of 0.977 (95% CI: 0.943∼1; cut-off value: -702Hu; sensitivity 96%; specificity, 90.5%; YI: 0.865), followed by the whole lung field 0.914 (95% CI: 0.830∼0.999; cut-off value: -727Hu; sensitivity 76%; specificity, 95.2%; YI: 0.712) and the middle-lung field 0.87 (95% CI: 0.768∼0.971; cut-off value: -779Hu; sensitivity 80%; specificity, 85.7%; YI: 0.657).

Conclusion

The present study indicated that the average lung CT number could be used to evaluate the relationship between the severity of PQ-induced lung injury and prognosis, especially in the lower-lung field. However, further research is needed to draw a clear conclusion.

Advances in the Use of N-Acetylcysteine in Chronic Respiratory Diseases

N-acetylcysteine (NAC) is widely used because of its mucolytic effects, taking part in the therapeutic protocols of cystic fibrosis. NAC is also administered as an antidote in acetaminophen (paracetamol) overdosing. Thanks to its wide antioxidative and anti-inflammatory effects, NAC may also be of benefit in other chronic inflammatory and fibrotizing respiratory diseases, such as chronic obstructive pulmonary disease, bronchial asthma, idiopathic lung fibrosis, or lung silicosis. In addition, NAC exerts low toxicity and rare adverse effects even in combination with other treatments, and it is cheap and easily accessible. This article brings a review of information on the mechanisms of inflammation and oxidative stress in selected chronic respiratory diseases and discusses the use of NAC in these disorders.

Remarkable Recovery in a Patient with Lethal Dose Paraquat Poisoning: A Case Report

Paraquat emerges as a formidable medical dilemma in Southeast Asia, its toxic effects attributed to the generation of free radicals and oxidative stress, with a specific predilection for diverse tissues, most notably the lungs. The scarcity of effective treatment modalities in resource-constrained settings magnifies the magnitude of the paraquat poisoning predicament. This report outlines the successful management of a 25-year-old man who ingested a lethal dose of paraquat. The patient presented solely with dysphagia devoid of accompanying symptoms, regardless of ingesting a fatal quantity of paraquat. The diagnosis was made based on history and a thorough clinical examination. Early, aggressive treatment with pulse therapy of steroids and antioxidants led to unexpected and quirky recovery. The case stresses the importance of prompt management and highlights the need for more research and public education to prevent future cases.

Keywords

antioxidants; case reports; corrosive; paraquat; steroids.

Case report: Lung transplantation for treatment of paraquat intoxication: timing of transplantation

Objective: To analyze the optimal timing of lung transplantation and summarize postoperative complications and their management after paraquat poisoning. Methods: Here, we present the clinical course of a 17-year-old boy with paraquat poisoning, in whom bilateral lung transplantation (LT) was performed. We reviewed the eight previously published articles relevant to LT after paraquat poisoning to summarize the therapeutic strategy. Results: A 17-year-old boy was admitted to the hospital after ingestion of 30-50 mL 25% paraquat. Mechanical ventilation was initiated on the 25th day after intoxication. Venovenous extracorporeal membrane oxygenation was initiated on the 26th day. Sequential bilateral LT was performed on the 27th day. Several complex postoperative complications occurred and the patient was discharged on the 50th day postoperatively. Eight case reports were included in the literature review, including 11 patients with paraquat poisoning undergoing LT. Three patients died due to paraquat poisoning leading to fibrosis in the transplanted lungs or postoperative complications. Eight patients survived during follow-up. Conclusion: LT after herbicide poisoning should be planned when hepatorenal function starts to recover, and waiting for complete recovery is unnecessary. Prevention of infection before surgery is important to reduce the incidence of postoperative infection. Complex perioperative complications caused by the herbicide itself or the late timing of transplantation can be successfully managed by a multidisciplinary team.

Oxygen Therapy Part 2 - Indications and Toxicity

Oxygen Therapy Part 2: Indications and ToxicityWemple et al. continue their review of oxygen therapy, discussing the acute and chronic indications for oxygen and the delivery of supplemental oxygen (and its potential adverse effects and toxicity).

A novel mechanism of Dimethyl ester of Alpha-ketoglutarate in suppressing Paraquat-induced BEAS-2B cell injury by alleviating GSDME dependent pyroptosis

BACKGROUND

Acute lung injury (ALI) induced by paraquat (PQ) progresses rapidly, leading to high mortality; however, there is no specific antidote. Our limited knowledge of the pathogenic toxicological mechanisms of PQ has hindered the development of treatments against PQ exposure.

PURPOSE

Pyroptosis is a form of programmed cell death recently identified as a novel molecular mechanism adopted by chemotherapeutic drugs for cancer therapy. However, the involvement of pyroptosis in PQ-induced lung injury has not been reported. Therefore, we investigated the effects of PQ on the lung tissues to elucidate the molecular mechanisms underlying its toxicity, especially its ability to induce pyroptosis.

METHODS

To observe the morphological changes of BEAS-2B cells exposed to PQ, the plasma membrane damage of the cells was detected by LDH release assay, mitochondrial function and cell metabolism were detected by energy metabolism analysis. Western blotting was used to detect the protein levels of GSDMD, C-GSDMD, GSDME and N-GSDME in BEAS-2B cells. Metabolites of TCA cycle were detected by metabolomics, and the changes of TCA cycle metabolic enzymes in cells were detected by Western blotting.

RESULTS

We observed that PQ induced proteolytic cleavage of gasdermin E (GSDME) with concomitant cleavage of caspase 3 in BEAS-2B cells. Knockout of GSDME attenuated PQ-induced cell death. Additionally, PQ induced ROS accumulation, mitochondrial depolarisation, and mitochondrial dysfunction in these cells. PQ activated the caspase 3/GSDME pathway and damaged the cytoplasmic membrane in cells, leading to pyroptosis. We demonstrated that DMK suppressed PQ-induced pyroptosis by blocking PQ-induced caspase 3/GSDME pathway activation, reducing cellular ROS levels, and improving mitochondrial function.

CONCLUSION

These findings provide novel insights into the previously unrecognized mechanism of GSDME-dependent pyroptosis in PQ poisoning.

Comparison of the drinking water standard for pesticides of the Brazil with other countries

The objective was to compare the types and concentrations of pesticides allowed in the water potability standard for human supply in Brazil with other countries considered to be the largest consumers of pesticides in dollars invested in purchase/trade. This is a descriptive and documentary study, with data collection in regulations available in official government websites in Brazil, USA, China, Japan, France, Germany, Canada, Argentina, India, Italy, and World Health Organization (WHO). Since Germany, France and Italy are part of the European Union (EU), the legislative resolution of the European Parliament was adopted. Pesticides number and maximum permitted values (MPV) differ between the countries and WHO. In the Brazilian ordinance there are forty pesticides, a number like the USA, Canada, China, and WHO, but that represents only 8% of the total pesticides registered for agricultural use in Brazil. When comparing the ordinance of Brazil with EU the values are only the same for Aldrin + Dieldrin. For other, amounts between 2 and 5000 times more are allowed in Brazil. Brazilian regulations do not establish a total value for the mixture of pesticides in water, only individual limits, which together can reach 1677.13 μg/L, while in EU standards it is only 0.5 μg/L. The study showed discrepancies of the pesticides allowed in water potability standard of the Brazil with other countries, but features 12 pesticides with the same concentrations as WHO guidelines, thus, a worldwide standardization in water potability regulations is necessary to promote health and reducing risk of exposure.

Serum creatinine in predicting mortality after paraquat poisoning: A systematic review and meta-analysis

Although the prognostic value of blood creatinine levels in patients with paraquat (PQ) poisoning has been studied for a long time, the results are still controversial. Therefore, we performed the first meta-analysis to comprehensively assess the value of blood creatinine in predicting the prognosis of patients with PQ poisoning. We searched PubMed, EMBase, Web of Science, ScienceDirect, Cochrane Library, China National Knowledge Infrastructure, China Science and Technology Journal Database, and China Online Journals to identify all relevant papers published up to June 2022. Data were extracted for pooled analysis, heterogeneity testing, sensitivity analysis, publication bias analysis, and subgroup analysis. Ultimately, 10 studies involving 862 patients were included. The I2 of diagnostic odds ratio (DOR), sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of this study were all greater than 50%, which showed the existence of heterogeneity in this study, and a random effects model was used for the combination of the above five effect sizes. Pooled analysis showed a high predictive value of blood creatinine for prognosis of PQ poisoning [pooled DOR:22.92, 95% confidence interval (CI):15.62-33.65, P < 0.001]. The combined sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were 86% (95% CI: 0.79-0.91), 78% (95% CI: 0.69-0.86), 4.01 (95% CI: 2.81-5.71), and 0.17 (95% CI: 0.12-0.25), respectively. Deeks publication bias test revealed there was publication bias. Sensitivity analysis showed no significant differences in the estimates of impact. Serum creatinine is an effective predictor of mortality in patients with PQ poisoning.

HIF-1α promotes paraquat induced acute lung injury and implicates a role NF-κB and Rac2 activity

Paraquat (PQ) is a bipyridine herbicide and oral exposure is the main way of PQ exposure with a very high mortality. At present, it is believed that large number of oxygen free radicals are generated and cause lipid peroxidation of tissue and organ cell membranes after PQ is absorbed. PQ exposure could cause multiple organ dysfunction, among which acute lung injury is the most common and most serious. However, its specific mechanism is still unclear. In this study, the C57BL/6J mouse (alveolar epithelial cell-specific knockout HIF-1α) model of acute lung injury (40 mg/kg PQ) at several time pointes and a model of acute type II alveolar epithelial cell (A549, 800 μM PQ) injury constructed. The oxidative stress (ROS, MDA) and inflammatory response (IL-1β, IL-6, TNF-α) were significantly inhibited in the alveolar epithelial cell-specific knockout of HIF-1α mice and siRNA technology to inhibit HIF-1α in alveolar epithelial cells. Further proteomic analysis showed that the expression of Rac2 protein, which is closely related to oxidative stress, was significantly increased after PQ exposure. And the inhibition of Rac2 expression in vitro significantly alleviated PQ-induced oxidative stress and inflammatory response. The expression of Rac2 protein was regulated by HIF-1α. The above suggests that HIF-1α may promote oxidative stress and inflammatory response in alveolar epithelial cells by regulating the expression of Rac2, and then participate in the promotion of PQ exposure-induced acute lung injury.

A rapid and reliable immunochromatographic strip for detecting paraquat poinsoning in domestic water and real human samples

Paraquat (PQ) is one of the most commonly used herbicides, but it has polluted the environment and threatened human health through extensive and improper usage. Here, a new naked-eye PQ immunochromatographic strip was developed to recognize PQ in domestic water and real human samples within 10 min based on a novel custom-designed anti-PQ antibody. The PQ test strip could recognize PQ at a concentration as low as 10 ng/ml, reaching the high-efficiency time-of-flight mass spectrometry detection level and identifying trace amounts of PQ in samples treated with a diquat (DQ) and PQ mixture. Notably, both the performance evaluation and clinical trial of the proposed PQ strips were validated in multiple hospitals and public health agencies. Taken together, our study firstly provide the clinical PQ-targeted colloidal gold immunochromatographic test strip designed both for environment water and human sample detection with multiple advantages, which are ready for environmental monitoring and clinical practice.

Protective activities of ellagic acid and urolithins against kidney toxicity of environmental pollutants: A review

Oxidative stress and inflammation are two possible mechanisms related to nephrotoxicity caused by environmental pollutants. Ellagic acid, a powerful antioxidant phytochemical, may have great relevance in mitigating pollutant-induced nephrotoxicity and preventing the progression of kidney disease. This review discusses the latest findings on the protective effects of ellagic acid, its metabolic derivatives, the urolithins, against kidney toxicity caused by heavy metals, pesticides, mycotoxins, and organic air pollutants. We describe the chelating, antioxidant, anti-inflammatory, antifibrotic, antiautophagic, and antiapoptotic properties of ellagic acid to attenuate nephrotoxicity. Furthermore, we present the molecular targets and signaling pathways that are regulated by these antioxidants, and suggest some others that should be explored. Nevertheless, the number of reports is still limited to establish the efficacy of ellagic acid against kidney damage induced by environmental pollutants. Therefore, additional preclinical studies on this topic are required, as well as the development of well-designed clinical trials.

Immunosuppressive therapies attenuate paraquat-induced renal dysfunction by suppressing inflammatory responses and lipid peroxidation

Although paraquat (PQ) induces oxidative damage and inflammatory responses in the lungs, the mechanism underlying PQ-induced acute kidney injury in patients is unclear. Immunosuppressive therapy with glucocorticoids and the immunosuppressant cyclophosphamide (CP) has been employed to treat patients with PQ poisoning. This study examined whether PQ could concurrently cause renal injury, inflammatory responses, and oxidative damage in the kidneys, and whether CP and dexamethasone (DEX) could suppress PQ-induced alterations. Mice were assigned to eight groups: Control, PQ, DEX, PQ plus DEX, CP, PQ plus CP, DEX plus CP, and PQ plus DEX with CP. DEX, CP, and DEX plus CP reversed PQ-induced renal injury, as indicated by urinary albumin-to-creatinine ratios and urea nitrogen levels in serum. The treatments also attenuated PQ-induced renal infiltration of leukocytes and macrophages and induction of the Il6, Tnf, Icam, Cxcl2, Tlr4, and Tlr9 genes encoding the inflammatory mediators in the kidneys. However, DEX only partially suppressed the macrophage infiltration, whereas DEX plus CP provided stronger protection than DEX or CP alone for the induction of Il6 and Cxcl2. Moreover, through the detection of F₂-isoprostanes (F₂-IsoPs) and isofurans in the kidneys and lungs and F₂-IsoPs in the plasma and urine, the therapies were found to suppress PQ-induced lipid peroxidation, although DEX was less effective. Finally, PQ decreased ubiquinol-9:ubiquinone-9 ratios in the kidneys. This effect of PQ was not found under CP treatment, but the ratio was lower than that of the control group. Our findings suggest that the suppression of PQ-induced inflammatory responses by DEX and CP in the kidneys can mitigate oxidative damage and acute kidney injury.

The efficacy of hemodialysis on paraquat poisoning mortality: A systematic review and meta-analysis

BACKGROUND

Paraquat (PQ) poisoning is a serious public health concern, especially in developing countries, due to its easy access and lack of awareness of potential harms. No effective treatment has been reported yet. Conventional hemodialysis (HD) is still used in many centers for excreting PQ or reducing acute kidney injury, but there is no consensus on its efficacy. Therefore, we aimed to review the HD efficacy in PQ poisoning mortality.

MATERIALS AND METHODS

We searched Web of Science, PubMed, Excerpta Medical Database, Google Scholar, Scopus, Cochrane, Web of Knowledge, Pro-Quest, ScienceDirect, Springer, Clinical Key, Scientific Information Database, Magiran, and Iran-doc, in publications before January 1, 2020. We compared patients who underwent HD (Group 1) with those who did not (Group 2). The outcome was considered mortality/survival. The data were analyzed by Comprehensive Meta-analysis Software.

RESULTS

This systematic review and meta-analysis included five studies with a combined total of 203 patients. The patients in the Group 1 had higher mortality than Group 2 (odds ratio, 2.84; 95% confidence interval: 1.22-6.64; P = 0.02). There was no evidence of publication bias (P value for Egger's test = 0.833).

CONCLUSION

Although HD did not affect the survival of patients, other variables such as the amount of ingested PQ, poisoning severity, the time between PQ ingestion and the start of HD, duration, and times of HD sessions may influence the results regarding mortality.

Prediction of mortality and morbidity following paraquat poisoning based on trend of liver and kidney injury

Background

Paraquat is a non-selective herbicide that causes severe tissue damage in various organs including the liver and kidney. The aim of this study was to determine the trend of the liver and kidney injury in patients with paraquat poisoning.

Methods

This retrospective cross-sectional study was performed at the Khorshid Hospital referral poisoning emergency center. The medical records of all patients with acute paraquat poisoning admitted from March 2017 to October 2020 were reviewed. Demographic factors, liver and kidney function tests and outcomes were recorded. Patients were divided into two groups based on the outcome of mortality (death or survived). The two groups were compared in terms of changes in creatinine and liver enzymes during hospitalization.

Results

A significant difference in mean creatinine levels between the two groups was observed from the third day after admission. The peak median Cr was 3.5 mg/dl for deceased patients in day 6 and 1.47 mg/dl for survived patients on 4th day. Minor elevations of ALT and AST were present in those who died. Logistic regression analysis shows patients who had level of creatinine higher than normal from the 2nd to 6th day post overdose, the risk of mortality was 4.83 to 7.44 times more than patients with normal creatinine level. The mean (SD) area under the curve for outcome prediction was reported to be excellent for creatinine on the 8th day post overdose (85.7 ± 13.2). Creatinine was higher than 2 on the 8th day post ingestion and had a sensitivity 100% and specificity 85.7% for mortality prediction (P value, 0.05).

Conclusions

The risk of mortality secondary to paraquat ingestion was highly associated with a rise in creatinine. Minor elevations of ALT and AST were also present in those who died. The creatinine concentration on different days post overdose can be helpful in predicting the severity of poisoning especially when the serum paraquat levels are not available.

The toxicokinetics of acute paraquat poisoning in specific patients: a case series

Paraquat is a non-selective contact herbicide that is absorbed through the digestive tract and skin and can cause multiple organ damage. The toxicokinetics of paraquat poisoning in specific patients are rarely reported. Case 1 was a 76-year-old man who intermittently immersed his perineum in diluted paraquat solution for 3 consecutive days because of eczema of the perineal skin. On admission, the patient’s scrotal skin was severely corroded and his blood paraquat concentration was 0.5 μg/mL. He developed severe kidney and lung damage after admission and died on Day 6 of admission. Case 2 was a 23-year-old woman who ingested paraquat during gestational week 36. Her initial blood paraquat concentration was 0.81 μg/mL. The patient refused hemoperfusion and a cesarean section. She birthed a baby girl 83 hours after ingesting paraquat. Paraquat concentrations in postnatal maternal blood, fetal blood, umbilical cord blood, and amniotic fluid were 0.19 μg/mL, 0.23 μg/mL, 0.20 μg/mL, and 0.47 μg/mL, respectively. The baby died within hours of birth and the mother died of refractory respiratory failure 2 days after delivery. This paper provides clues about paraquat toxicokinetics in specific patient types and indicates that paraquat can be absorbed through the scrotal skin and the placental barrier.

Thyroid Cancer and Pesticide Use in a Central California Agricultural Area: A Case Control Study

OBJECTIVE

To examine environmental factors that influence risk of thyroid cancer.

METHODS

We performed a case-control study utilizing thyroid cancer cases from the California Cancer Registry (1999-2012) and controls sampled in a population-based manner. Study participants were included if they were diagnosed with thyroid cancer, lived in the study area at their time of diagnosis, and were ≥35 years of age. Controls were recruited from the same area and eligible to participate if they were ≥35 years of age and had been living in California for at least 5 years prior to the interview. We examined residential exposure to 29 agricultural use pesticides, known to cause DNA damage in vitro or are known endocrine disruptors. We employed a validated geographic information system-based system to generate exposure estimates for each participant.

RESULTS

Our sample included 2067 cases and 1003 controls. In single pollutant models and within a 20-year exposure period, 10 out of 29 selected pesticides were associated with thyroid cancer, including several of the most applied pesticides in the United States such as paraquat dichloride [odds ratio (OR): 1.46 (95% CI: 1.23, 1.73)], glyphosate [OR: 1.33 (95% CI: 1.12, 1.58)], and oxyfluorfen [OR: 1.21 (95% CI: 1.02, 1.43)]. Risk of thyroid cancer increased proportionately to the total number of pesticides subjects were exposed to 20 years before diagnosis or interview. In all models, paraquat dichloride was associated with thyroid cancer.

CONCLUSIONS

Our study provides first evidence in support of the hypothesis that residential pesticide exposure from agricultural applications is associated with an increased risk of thyroid cancer.

Evidence for the efficacy of the emetic PP796 in paraquat SL20 formulations - a narrative review of published and unpublished evidence

BACKGROUND

The bipyridyl herbicide paraquat was first introduced into agriculture in the 1960s by Imperial Chemical Industries. Due to issues with unintentional poisoning, the centrally acting emetic PP796 was added in 1976 to the company's 20% paraquat ion soluble liquid (SL20) formulations (Gramoxone^®) at a concentration of 0.5 g/L or 0.05% (equivalent to 0.071 mg/kg in a 70 kg adult ingesting a minimum lethal dose of 10 mL) to induce early vomiting (within 30 min), reduce paraquat absorption from the gut, and prevent deaths. Its presence in paraquat products was subsequently mandated by the Food and Agriculture Organization Committee of Experts on Pesticides in Agriculture (predecessor to the current FAO/WHO Joint Meeting on Pesticide Specifications). However, no primary pre-clinical or clinical data have been published regarding the effectiveness of PP796. We reviewed the published literature and unpublished company reports for data on the effectiveness of PP796.

METHODS

PubMed and Google were searched for published studies on the emetic using the search terms "paraquat" and ["emetic" or "PP796"]. Company documents reporting pre-clinical and clinical studies were accessed at the website of U.S. Right to Know (https://usrtk.org/pesticides/paraquat-papers/). Primary study reports were sought as well as overviews written by company toxicologists.

RESULTS

Pre-clinical dog and monkey studies indicated that the PP796 EC50 dose for vomiting was around 0.5-2 mg/kg. Further increasing the PP796 concentration speeded up the time to first vomit and reduced the amount of paraquat absorbed (as assessed by the 0-24 h plasma area-under-the-curve) 100-fold compared to a control group receiving no PP796. However, the dose selected for paraquat SL20 formulations by the company (0.5 g/L or 0.05%) was based exclusively on a phase II study in the early 1970s involving five volunteers receiving 3 different doses, with only two individuals actually vomiting, supplemented by data from 37 patients taking 2 mg in clinical trials. A UK-mandated toxicovigilance study in the 1980s identified only 21 patients ingesting paraquat SL20 with PP796 for whom data on time to vomit was available; of these patients, 11 vomited within 30 min (52.4%, 95%CI 31-73.7%). No effect on mortality could be identified from any study of paraquat SL containing 0.05% PP796. A clinical study in Sri Lanka 30 years after the emetic was first introduced, of a revised formulation (Gramoxone^® Inteon) containing a three-fold higher amount of PP796, as well as MgSO4 and an alginate, showed increased rates of early vomiting and modestly reduced mortality for patients ingesting up to 100 mL.

CONCLUSION

Pre-clinical studies showed a clear dose response for PP796 to cause early vomiting, with effective doses in the 0.5-20 mg/kg range. A too low concentration of PP796 was selected for paraquat formulations based on an inadequate phase II study. Currently, evidence that PP796 at 0.05% in paraquat SL20 causes more rapid vomiting after ingestion is weak or unpublished; no evidence of clinical benefit or fewer deaths has been identified. There is no evidence to support the FAO/WHO Joint Meeting on Pesticide Specifications mandate to include PP796 or any other emetic in paraquat products. Products with higher emetic concentrations have been developed but are not widely used; it is possible they may prevent deaths.

Case Report: Paraquat poisoning

Paraquat (1, 1′-dimethyl-4,4′-bipyridinium) is a commonly used herbicide that is highly toxic when ingested. Ingestion of toxic doses of paraquat has serious complications on the lungs, gastrointestinal tract, kidney, liver, and other organs. Due to its inherent toxicity and the lack of a specific antidote, it has a high case fatality rate. Despite being restricted to commercially licensed users in Nepal, it is a common herbicide causing both intentional and accidental poisoning. Although there have been numerous anecdotal cases of paraquat poisoning in Nepal, no reports have been published in the literature. . We report a case of a 30-year old female, who developed gastrointestinal symptoms like vomiting, diarrhoea and odynophagia, renal and liver injury after accidental ingestion of 10ml of 20% paraquat. Symptoms and organ involvement subsided with timely and appropriate supportive management.