Failure of continuous venovenous hemofiltration to prevent death in paraquat poisoning

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.

Ferulic acid grafted into β-cyclodextrin nanosponges ameliorates Paraquat-induced human MRC-5 fibroblast injury

Paraquat (PQ) is a commercially important and effective herbicide in the world. Nevertheless, it has higher toxicity causing acute organ damage and different complications, mainly in the lungs and kidneys. Ferulic acid (FA), 4-hydroxy-3-methoxycinnamic acid imposes multiple pharmacological impacts. No protective effect of FA on PQ poisoning-caused human embryonic lung fibroblast damage has not been reported. Despite their many beneficial effects, FA is characterized by poor water solubility, low bioavailability, and phytochemical instability. To solve the problem, β-cyclodextrin nanosponge (β-CD NSs) was utilized to increase the solubility of FA so that it was grafted into β-CD NSs to establish β-CD@FA NSs. The purpose of this work was to examine for the first time the protective effect of β-CD@FA NS on MRC-5 human lung cells damages induced by PQ poisoning. MTS assay was performed to investigate the viability of MRC-5 cells at different concentrations of FA/β-CD@FA NSs when cells were co-cultured with 0.2 μg/mL PQ. The flow cytometry study was carried out to determine apoptosis. Malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) levels were detected using appropriate biochemistry kits. Compared with the PQ group, the cell activity, CAT, and SOD levels were significantly increased in the FA and chiefly in β-CD@FA NSs intervention groups, whereas apoptosis and MDA levels were markedly decreased. The inflammatory factors tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), and interleukin 22 (IL-22) were detected. The results demonstrate that β-CD@FA NSs can inhibit PQ-induced cell damage by enhancing antioxidant stress capacity and regulation of inflammatory responses.

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.

Plasma Concentration After the First Hemoperfusion has a High Predictive Value in Medium Level Acute Paraquat-Poisoned Patients

BACKGROUND

Paraquat ( PQ) is very poisonous to humans and animals and there is no effective clinical antidote . The efficacy of hemoperfusion (HP) treatment for PQ poisoning remains controversial. To explore new ways to predict the prognosis of patients with acute PQ poisoning and assist in the development of better hemopurification treatment strategies.

METHODS

The clinical data of patients who were intoxicated with PQ through contact were diagnosed with PQ poisoning by high-performance liquid chromatography. Samples were collected by the Emergency Intensive Care Unit of the First Affiliated Hospital of Wenzhou Medical University from January 2012 to November 2016. Based on the prognosis, the patients were grouped into survival and death groups. Comparisons of the differences in the clinical indexes were performed, including the initial concentration of PQ at admission, PQ concentration after first HP, the number of HP cartridges used for the first hemoperfusion, whether HP was combined with continuous renal replacement therapy, and the number of concurrent organ injuries between the 2 groups. In addition, data were analyzed using multivariate logistic regression models and receiver operating characteristic curves. Moreover, prognostic factors in patients with acute PQ poisoning were analyzed.

RESULTS

Overall, 128 patients with acute PQ poisoning were enrolled in this study. The median plasma PQ concentrations of the patients at admission were 21 and 834 ng/mL (range: 50-1,099,118 ng/mL). The multiple logistic regression model revealed that the initial concentration of PQ and the PQ concentration after the first perfusion were independent risk factors for death in patients with acute PQ poisoning. The PQ concentration in the survival group after the first HP was <516 ng/mL and was mainly distributed at approximately 100 ng/mL. The percentage of patients whose concentration after the first HP was <516 ng/mL in the death group was only 19%.

CONCLUSIONS

The initial plasma PQ concentration after admission and PQ concentration after the first HP are risk factors for death in patients with acute PQ poisoning. Moreover, PQ concentration after the first HP had a high predictive value for death. When the initial plasma PQ concentration after admission ranges from 50 ng/mL to 5000 ng/mL, the rapid reduction in plasma PQ concentration after HP treatment could improve the prognosis of patients with acute PQ poisoning.

Influence of strengthened hemoperfusion combined with continuous venovenous hemofiltration on prognosis of patients with acute paraquat poisoning: SHP + CVVH improve prognosis of acute PQ patients

Background

The success rate of rescue is extremely low in acute paraquat poisoning. This study aimed to assess whether strengthened hemoperfusion (SHP) combined with continuous venovenous hemofiltration (CVVH) improves prognosis in patients with acute paraquat poisoning.

Methods

Patients from January 2005 to December 2018 were enrolled retrospectively. All selected patients were administered conventional therapy. They were divided according to the received treatments in the conventional therapy, hemoperfusion (HP), CVVH, SHP and SHP + CVVH groups. Follow-up was implemented until the 90th day after poisoning. Other outcomes included all-cause mortality on the 15th day after poisoning, and the percentages of respiratory failure and mechanical ventilation use.

Results

The study included 487 patients,and 211 died in all. Mortality rate in the SHP + CVVH group on the 90th day after poisoning was significantly decreased compared with those of other groups (p<0.001). Survival curves of all groups showed significant differences (p<0.001). SHP combined with CVVH was an independent factor reducing mortality risk (p<0.001). Mortality rate in the SHP + CVVH group on the 15th day after poisoning was also significantly decreased (p < 0.05). The proportions of patients in the SHP + CVVH group with acute respiratory failure and mechanical ventilation were significantly lower than those of other groups (p < 0.05).

Conclusions

SHP with CVVH may decrease the mortality rate of patients with acute paraquat poisoning on the 90th day after poisoning and improve the prognosis.

Supramolecular Hunter Stationed on Red Blood Cells for Detoxification Based on Specific Molecular Recognition

Efficient removal of deadly toxicants by blood purification remains predominant in poisoning treatment. Current strategies mainly rely on absorptive scavengers that normally have no selectivity to the adsorbates, which could result poor clinical outcomes to certain toxic species due to the passivity and inaccuracy of the detoxification procedure. Herein, a positive, accurate, and customized detoxification strategy was proposed. Based on the sophisticated molecule design and thoughtful structure analysis of the aimed toxicant paraquat, a supramolecular hunter stationed on red blood cells (RBC) is developed to continuously track paraquat in the blood. In this construct, a Janus dendrimer amphiphile (JDA) molecule was synthesized with the aim of facilely anchoring onto RBC membranes while bridging to load the antidote WP6 that could precisely recognize paraquat. In vitro and in vivo results demonstrate the effective toxicant-hunting and harm-neutralizing capability of the system through a guest-exchange reaction. This strategy provides a different insight in designing scavengers that can actively, precisely, and continuously hunt toxicants through a supramolecular approach.

Paraquat Poisoning: A Retrospective Study of 55 Patients From a Tertiary Care Center in Southern India

Background

In India the data on paraquat (PQ) poisoning are limited to case reports and small case series. Hence, this study was carried out to understand the clinical features and outcomes of PQ poisoning. We also briefly report the relevant Indian studies on PQ poisoning.

Materials and methods

This was a retrospective case record-based study of PQ poisoning victims admitted over a period of 5 years.

Results

Of the 55 patients included in this study, the in-hospital mortality rate was 72.7%. Acute kidney injury was the most common manifestation. The use of cyclophosphamide did not affect the clinical outcome. Hemoperfusion (HP) was not done for any patient. Pulmonary edema and acute tubular necrosis were the most common histopathological findings.

Conclusion

In India, this is one of the most comprehensive studies of PQ toxicity. Hence, we hope that this information would be of use to clinicians who deal with PQ poisoning.

How to cite this article

Ravichandran R, Amalnath D, Shaha KK, Srinivas BH. Paraquat Poisoning: A Retrospective Study of 55 Patients from a Tertiary Care Center in Southern India. Indian J Crit Care Med 2020;24(3):155–159.

An Eco- and User-Friendly Herbicide

The increasing use of pesticides in agriculture and gardening has caused severe deterioration to both the ecosystem and the health of users (human beings), so there is an urgent need for eco- and user-friendly pesticides. Among a variety of herbicides, paraquat (PQ), frequently used as an effective herbicidal agent worldwide, is well-known for its serious toxicity that has killed, and harmed, thousands of people and countless wildlife such as fish. Herein, we present a facile supramolecular formulation of PQ@cucurbit[7]uril (PQ@CB[7]), prepared by simply mixing PQ with equivalent (molar) CB[7] in water. With addition of CB[7], PQ's cellular uptake was dramatically inhibited. The reactive oxygen species (ROS) generation and the associated apoptosis otherwise induced by PQ in cellular models were both reduced, resulting in increased cellular viability. In a wildtype zebrafish model that is a typical fragile wildlife species in the ecosystem, the supramolecular formulation exhibited significantly reduced hepatotoxicity and increased survival rate, in comparison with those of the fish exposed to free PQ. In a mouse model that is clinically relevant to human being, the administration of PQ@CB[7] significantly alleviated major organ injuries and unusual hematological parameters that were otherwise induced by free PQ, resulting in a significantly increased survival rate. Meanwhile, this formulation maintained effective herbicidal activity that was equivalent to that of free PQ. Taken together, this facile supramolecular PQ formulation is providing not only an extremely rare example of an eco- and user-friendly herbicide that has been desired for decades but also a practical solution for green agriculture.

Clinical features and risk factors of acute kidney injury in children with acute paraquat intoxication

Objective

This study aimed to investigate the clinical features and risk factors of acute kidney injury (AKI) in children with acute paraquat intoxication.

Methods

A retrospective study of 110 hospitalized children with acute paraquat intoxication in West China Second University Hospital, Sichuan University was conducted from January 2010 to May 2017. The Kaplan–Meier method was used to compare the survival rates of children with different AKI stages. Multivariate logistic regression was applied to analyse the risk factors for paraquat-induced AKI.

Results

AKI occurred in 42 of 110 (38.2%) children. We observed AKI stage 1 in two (4.8%) children, AKI stage 2 in 11 (26.2%), and AKI stage 3 in 29 (69.0%). The survival rate of children in AKI stage 3 (34.5%) was significantly lower than that in children in AKI stage 2 (63.6%) and AKI stage 1 (100%). Multivariate analysis showed that oral ulcers and elevated blood glucose levels were significant independent risk factors for paraquat-induced AKI in children (odds ratio = 4.223 and 5.545, respectively).

Conclusions

The incidence and mortality rates of paraquat-induced AKI in children are high. Oral ulcers and elevated blood glucose levels are independent risk factors affecting the occurrence of paraquat-induced AKI in children.

Necrostatin-1 Protects Against Paraquat-Induced Cardiac Contractile Dysfunction via RIP1-RIP3-MLKL-Dependent Necroptosis Pathway

Paraquat is a highly toxic prooxidant that triggers oxidative stress and multi-organ failure including that of the heart. To date, effective treatment of paraquat toxicity is still not established. Necroptosis, a newly discovered form of programmed cell death, was recently shown to be strongly associated with cardiovascular disease. Receptor interaction proteins 1 (RIP1), receptor interaction proteins 3 (RIP3), and mixed lineage kinase domain like (MLKL) are key proteins in the necroptosis pathway. Necrostatin-1 (Nec-1) is a specific inhibitor of necroptosis which acts by blocking the interaction between RIP1 and RIP3. In the present study, we studied the effect of Nec-1 on paraquat-induced cardiac contractile dysfunction and reactive oxygen species (ROS) production in the heart tissues using a mouse model. Our results revealed impaired contractile function, deranged intracellular Ca²⁺ handling and echocardiographic abnormalities in mice challenged with paraquat. We further found enhanced expressions of RIP1, RIP3, and MLKL along with overproduction of ROS in mice heart tissues. Nec-1 pre-treatment prevented cardiac contractile dysfunction in paraquat-challenged mice. Furthermore, Nec-1 reduced RIP1-RIP3 interaction, down-regulated the RIP1-RIP3-MLKL signal pathway, and dramatically inhibited the production of ROS. Collectively, these findings suggest that Nec-1 alleviated paraquat-induced myocardial contractile dysfunction through inhibition of necroptosis, an effect which was likely mediated via the RIP1-RIP3-MLKL signaling cascade. Further, ROS appeared to play an important role in this process. Thus, this process may represent a novel therapeutic strategy for the treatment of paraquat-induced cardiac contractile dysfunction.

Does hemoperfusion in combination with other treatments reduce the mortality of patients with paraquat poisoning more than hemoperfusion alone: A systematic review with meta-analysis

Background:

Paraquat (PQ) poisoning is a serious public health problem in many countries. In spite of different treatments, the mortality is still high. We performed a meta-analysis to see whether hemoperfusion (HP) in combination with other treatments reduces the mortality more than HP alone in patients with PQ poisoning.

Materials and Methods:

We searched EMBASE, PubMed, Google Scholar, ISI Web of Knowledge, Cochrane Central Register of Controlled Trials, Scopus, Springer, TRIP, ProQuest, and references of the included studies from January 2000 to August 2017. Two reviewers independently searched and extracted data. We measured I² to determine variance contributed by heterogeneity. To investigate the publication bias, Begg's and Egger's tests were used along with funnel plot analysis.

Results:

Ultimately 12 articles were included in the meta-analysis. Five articles compared HP with conventional therapy with a total of 1311 patients, and seven articles compared mortality of patients received HP versus those received HP in combination with an additional treatment. HP alone reduced the odds of death (odds ratio [OR] = 0.20; 95% confidence interval [CI]: 0.11–0.40, P < 0.0001) compared to conventional therapy. Furthermore, the odds of death was higher in HP group compared to those received HP in combination of additional treatments (OR = 1.24; 95% CI: 1.05–1.46, P = 0.01).

Conclusion:

The mortality was less in HP-treated group compared to those received only conventional therapy. Addition of other treatments with HP reduced the mortality more than HP alone.

A Synthetic Receptor as a Specific Antidote for Paraquat Poisoning

Accidental or suicidal ingestion of the world's most widely used herbicide, paraquat (PQ), may result in rapid multi-organ failure with a 60% fatality rate due to the absence of an effective detoxification solution. Effective, specific antidotes to PQ poisoning have been highly desired. Methods: The binding constant of PQ and a synthetic receptor, cucurbit[7]uril (CB[7]), was first determined in various pH environments. The antidotal effects of CB[7] on PQ toxicity were firstly evaluated with in-vitro cell lines. With in-vivo mice models, the pharmacokinetics and the biodistribution of PQ in major organs were determined to evaluate the influence of CB[7] on the oral bioavailability of PQ. Major organs' injuries and overall survival rates of the mice were systemically examined to evaluate the therapeutic efficacy of CB[7] on PQ poisoning. Results: We demonstrate that CB[7] may complex PQ strongly under various conditions and significantly reduce its toxicity in vitro and in vivo. Oral administration of PQ in the presence of CB[7] in a mouse model significantly decreased PQ levels in the plasma and major organs and alleviated major organs' injuries, when compared to those of mice administered with PQ alone. Further studies indicated that oral administration of CB[7] within 2 h post PQ ingestion significantly increased the survival rates and extended the survival time of the mice, in contrast to the ineffective treatment by activated charcoal, which is commonly recommended for PQ decontamination. Conclusion: CB[7] may be used as a specific oral antidote for PQ poisoning by strongly binding with PQ and inhibiting its absorption in the gastrointestinal tracts.

Clinical Therapeutic Effect of Naloxone Combined with Hemodialysis on Acute Severe Alcoholism

Background

The aim of this research was to investigate the treatment effect of naloxone combined with hemodialysis on acute severe alcoholism.

Material/Methods

We included 36 patients treated with naloxone combined with hemodialysis in Group I and 34 patients treated with naloxone without hemodialysis in Group II. The Glasgow coma scale (GCS) score, the consciousness recovery time, alanine amino transferase (ALT) level, and complications were analyzed.

Results

Mean GCS score in Group I was higher than that in Group II, with a significant difference (P<0.05). The consciousness recovery time in Groups I and II were 3.0±0.8 h and 6.9±2.1 h, respectively, with a significant difference (P<0.05). After naloxone treatment and hemodialysis, the ALT level in Group I was lower than that in Group II (P<0.05). Moreover, the incidence of hepatic and renal function damages in Group I was smaller than that in Group II (P<0.05). Only 1 patient in Group I developed pneumonia, which was fewer than that in Group II, with a significant difference (P<0.05).

Conclusions

Naloxone combined with hemodialysis effectively reduces the central inhibition of alcohol, shortens consciousness recovery time, improves respiratory and cardiovascular function, decreases hepatic and renal function damages, and reduces the incidence of complications.

Treatment Outcome of Combined Continuous Venovenous Hemofiltration and Hemoperfusion in Acute Paraquat Poisoning: A Prospective Controlled Trial

OBJECTIVES

To investigate whether combined continuous venovenous hemofiltration and hemoperfusion among paraquat-poisoned patients would improve survival.

DESIGN

Prospective, controlled interventional study over 4 years.

SETTING

Single, tertiary, academic medical center.

PATIENTS

We recruited patients admitted to Shanghai Tenth People's Hospital within 48 hours after paraquat ingestion. Exclusions were under 14 years old, ingestion of paraquat with other toxicants, pregnant, a history of chronic pulmonary disease, psychosis, hyperthyroidism, or diabetes with impaired liver or renal function.

INTERVENTIONS

All patients were assigned to receive continuous venovenous hemofiltration with hemoperfusion therapy (continuous venovenous hemofiltration group) and to receive conventional therapy (conventional group). The study outcomes were death from any cause within 90 days after paraquat ingestion and the frequencies of hypoxia, acute kidney injury, or adverse events.

MEASUREMENTS AND MAIN RESULTS

Of the 110 enrolled patients, 59 were assigned to continuous venovenous hemofiltration group and 51 to conventional group. The two groups had similar baseline demographics and clinical features. At 90 days after paraquat ingestion, 19 of 59 patients (32.2%) in the continuous venovenous hemofiltration group and 29 of 51 patients (56.9%) in the conventional group had died (hazard ratio, 0.43; 95% CI, 0.24-0.76; p = 0.004). In multivariable Cox proportional hazard models controlling for baseline characteristics, combined continuous venovenous hemofiltration and hemoperfusion was independently associated with reduced risk of death compared with conventional therapy (adjusted hazard ratio, 0.35; 95% CI, 0.19-0.64; p = 0.001). Patients in the continuous venovenous hemofiltration group, as compared to the conventional group, had a reduced occurrence rate of hypoxia (40.7% vs 72.5%; p = 0.001) and of acute kidney injury (59.3% vs 78.4%; p = 0.03). Hypophosphatemia and thrombocytopenia were more common in the continuous venovenous hemofiltration group (p < 0.05).

CONCLUSIONS

In patients with paraquat poisoning, treatment with combined continuous venovenous hemofiltration and hemoperfusion significantly improved 90-day survival rates.

Predictors of acute kidney injury after paraquat intoxication

Paraquat intoxication is characterized by multi-organ failure, causing substantial mortality and morbidity. Many paraquat patients experience acute kidney injury (AKI), sometimes requiring hemodialysis. We observed 222 paraquat-intoxicated patients between 2000 and 2012, and divided them into AKI (n = 103) and non-AKI (n = 119) groups. The mortality rate was higher for AKI than non-AKI patients (70.1% vs. 40.0%, P < 0.001). Patients with AKI had a longer time to hospital arrival (P = 0.003), lower PaO₂ (P = 0.006) and higher alveolar-arterial O₂ difference (P < 0.001) 48 h after admission, higher sequential organ failure assessment 48-h score (P < 0.001), higher severity index of paraquat poisoning (SIPP) score (P = 0.016), lower PaCO₂ at admission (P = 0.031), higher PaO₂ at admission (P = 0.015), lower nadir PaCO₂ (P = 0.001) and lower nadir HCO₃ (P = 0.004) than non-AKI patients. Multivariate logistic regression indicated that acute hepatitis (P < 0.001), a longer time to hospital arrival (P < 0.001), higher SIPP score (P = 0.026) and higher PaO₂ at admission (P = 0.014) were predictors of AKI. The area under the receiver operating characteristic curve confirmed that an Acute Kidney Injury Network 48-hour score ≥ 2 predicted AKI necessitating hemodialysis with a sensitivity of 0.6 and specificity of 0.832. AKI is common (46.4%) following paraquat ingestion, and acute hepatitis, the time to hospital arrival, SIPP score and PaO₂ at admission were powerful predictors of AKI. Larger studies with longer follow-up durations are warranted.

Continuous venovenous hemofiltration in the management of paraquat poisoning: A meta-analysis of randomized controlled trials

BACKGROUND

Paraquat (PQ) poisoning is a widespread occurrence, especially in underdeveloped areas. The treatment of PQ poisoning has always been difficult, and there is currently no definite effective treatment. Continuous venovenous hemofiltration (CVVH) treatment for PQ poisoning has been widely used in clinical practice; however, its effect remains uncertain. Accordingly, the purpose of this meta-analysis was to evaluate the efficacy of CVVH in the treatment of PQ poisoning.

METHODS

We searched for relevant trials using PubMed, Embase, the Cochrane Library, and 3 Chinese databases, the Chinese BioMedical Literature Database, National Knowledge Infrastructure Database, and Wanfang Database. We included all qualified randomized controlled trials (RCTs) of CVVH treatment for patients with PQ poisoning. The primary outcome was mortality, while the secondary outcomes included the survival time and constituent ratios of death due to respiratory failure and circulatory failure.

RESULTS

Three RCTs involving 290 patients were included. The mortality rates of the intervention and control groups were 57.9% and 61.0%, respectively. Pooled analysis demonstrated no significant difference in mortality between the CVVH treatment and control groups (risk ratio [RR] 0.94, 95% confidence interval [CI]: 0.78-1.15, P = .56), with a low level of heterogeneity (X = 1.75, I = 0%). However, the CVVH group was associated with a longer survival time compared to the control group (weighted mean difference 1.73, 95% CI: 0.56-2.90, P = .004). Respiratory failure as the cause of death was more common in the CVVH group, as compared with the control group (RR 1.66, 95% CI: 1.24-2.23, P = .0008), whereas patients in the control group were more likely to die from circulatory failure than in the CVVH group (RR 0.56, 95% CI: 0.40-0.81, P = .002).

CONCLUSION

Although CVVH treatment might not noticeably reduce mortality for patients with PQ poisoning, it can prolong the survival time of the patients and improve the stability of the circulatory system, thereby enabling further treatment.

Golden Hours in Severe Paraquat Poisoning-The Role of Early Haemoperfusion Therapy

INTRODUCTION

Paraquat is a commonly ingested poison especially in Southern India. There is no antidote for paraquat poison and consumption is often fatal. The usual cause of death is either acute lung injury or multi-organ failure.

AIM

To evaluate the role of early haemoperfusion as a therapy in paraquat poisoned patients.

MATERIALS AND METHODS

This study was a retrospective analysis of patients admitted to a Tertiary Medical College Hospital between January 2012 and December 2015 with history of paraquat consumption, comparing outcomes in those who received only gastric lavage and symptomatic treatment with those who received haemoperfusion as a therapy. The role of early haemoperfusion (≤ 6 hours) vs late haemoperfusion (> 6 hours) in paraquat poisoned patients was also compared. The data of these patients was extracted and analysed with respect to age, sex, mode of treatment, the outcome in patients who received early and late haemoperfusion.

RESULTS

A total of 101 patients were studied out of which 62 died. Deaths were more in those patients who received only gastric lavage with symptomatic treatment as therapy compared to those who received haemoperfusion i.e., 92.1% vs 42.9% respectively. We also found that, the survival rate was better in patients who received early haemoperfusion.

CONCLUSION

Early haemoperfusion was helpful in the management of severe paraquat poisoning and improved the survival rate in these patients.

Prognosis and survival analysis of paraquat poisoned patients based on improved HPLC-UV method

Paraquat (PQ) has caused deaths of numerous people around the world. In order to assess the lethal plasma concentration, the patients who acquired acute PQ intoxication were analyzed by plasma concentration monitoring. The plasma PQ concentrations were determined by high performance liquid chromatography (HPLC) which used 5-bromopyrimidine as internal standard and trichloroacetic acid-methanol (1:9) as protein precipitant. The liver, kidney and coagulation function were determined by automatic biochemical analyzer. According to plasma PQ concentration, 90 patients were divided into four groups: trace PQ group (<50ng/mL), low PQ group (<1000ng/mL), medium PQ group (1000-5000ng/mL) and high PQ group (>5000ng/mL). The clinical data from the four groups was statistically analyzed. The results showed the developed HPLC methods exhibited a high degree of accuracy and good linearity within 50-25000ng/mL (R=0.9998). The Spearman's correlation analysis showed PQ concentration had a strong relationship to total bilirubin, direct bilirubin, aspartic transaminase, urea nitrogen, prothrombin time, prothrombin activity, and international normalized ratio (P<0.01). The cured or survival PQ poisoned patients among the trace PQ group, the low PQ group, the medium PQ group, and the high PQ group were 19/19 (100%), 19/21 (90.47%), 11/25 (44.0%), and 0/25 (0%) respectively. The mean hospital days were (10.37±8.04), (18.76±12.06), (16.76±14.44), and (4.04±5.41) days respectively. The Cox regression analysis indicated that plasma PQ concentration was highly related to prognosis (P<0.05). In conclusion, no patient presenting with a PQ concentration over 5000ng/mL survived. The plasma PQ level is related to liver, kidney and coagulation function, which can be used as an important clinical index to judge the prognosis of PQ poisoned patients.

CHEMICAL COMPOUNDS

Paraquat (PubChem CID: 15938), 5-bromopyrimidine (PubChem CID: 78344), acetonitrile (PubChem CID: 6342), sodium dihydrogen phosphate (PubChem CID: 23672064), sodium heptanesulfonate (PubChem CID: 23672332), methylprednisolone (PubChem CID: 6741), cyclophosphamide (PubChem CID: 2907).

Traditional chinese medicine Xuebijing treatment is associated with decreased mortality risk of patients with moderate paraquat poisoning

Paraquat poisoning causes multiple organ injury and high mortality due to severe toxicity and lack of effective treatment. Xuebijing (XBJ) injection, a traditional Chinese medicine preparation of five Chinese herbs (Radix Salviae Miltiorrhiae, Rhizoma Chuanxiong, Flos Carthami, Angelica Sinensis and Radix Paeoniae Rubra), has an anti-inflammatory effect and is widely used in the treatment of sepsis. This retrospective study was designed to evaluate the effects of XBJ combined with conventional therapy on mortality risk of patients with acute paraquat poisoning. Out of 68 patients, 27 were treated with conventional therapy (control group) and 41 were treated with intravenous administration of XBJ (100 ml, twice a day, up to 7 days) plus conventional therapy (XBJ group). Vital organ function, survival time within 28 days and adverse events during the treatment were reviewed. Results indicated that XBJ treatment significantly increased median survival time among patients ingesting 10-30 ml of paraquat (P=0.02) compared with the control group. After adjustment for covariates, XBJ treatment was associated significantly with a lower mortality risk (adjusted HR 0.242, 95% CI 0.113 to 0.516, P=0.001) compared with the control group. Additionally, compared with Day 1, on Day 3 the value of PaO2/FiO2 was significantly decreased, and the values of serum alanine aminotransferase, creatinine and troponin T were significantly increased in the control group (all P<0.05), but these values were significant improved in the XBJ group (all P<0.05). Only one patient had skin rash with itch within 30 minutes after injection and no severe adverse events were found in the XBJ group. In conclusion, XBJ treatment is associated with decreased mortality risk of patients with moderate paraquat poisoning, which may be attributed to improved function of vital organs with no severe adverse events.

Connective tissue growth factor stimulates the proliferation, migration and differentiation of lung fibroblasts during paraquat-induced pulmonary fibrosis

It is well established that paraquat (PQ) poisoning can cause severe lung injury during the early stages of exposure, finally leading to irreversible pulmonary fibrosis. Connective tissue growth factor (CTGF) is an essential growth factor that is involved in tissue repair and pulmonary fibrogenesis. In the present study, the role of CTGF was examined in a rat model of pulmonary fibrosis induced by PQ poisoning. Histological examination revealed interstitial edema and extensive cellular thickening of interalveolar septa at the early stages of poisoning. At 2 weeks after PQ administration, lung tissue sections exhibited a marked thickening of the alveolar walls with an accumulation of interstitial cells with a fibroblastic appearance. Masson’s trichrome staining revealed a patchy distribution of collagen deposition, indicating pulmonary fibrogenesis. Western blot analysis and immunohistochemical staining of tissue samples demonstrated that CTGF expression was significantly upregulated in the PQ-treated group. Similarly, PQ treatment of MRC-5 human lung fibroblast cells caused an increase in CTGF in a dose-dependent manner. Furthermore, the addition of CTGF to MRC-5 cells triggered cellular proliferation and migration. In addition, CTGF induced the differentiation of fibroblasts to myofibroblasts, as was evident from increased expression of α-smooth muscle actin (α-SMA) and collagen. These findings demonstrate that PQ causes increased CTGF expression, which triggers proliferation, migration and differentiation of lung fibroblasts. Therefore, CTGF may be important in PQ-induced pulmonary fibrogenesis, rendering this growth factor a potential pharmacological target for reducing lung injury.

An efficient machine learning approach for diagnosis of paraquat-poisoned patients

Numerous people die of paraquat (PQ) poisoning because they were not diagnosed and treated promptly at an early stage. Till now, determination of PQ levels in blood or urine is still the only way to confirm the PQ poisoning. In order to develop a new diagnostic method, the potential of machine learning technique was explored in this study. A newly developed classification technique, extreme learning machine (ELM), was taken to discriminate the PQ-poisoned patients from the healthy controls. 15 PQ-poisoned patients recruited from The First Affiliated Hospital of Wenzhou Medical University who had a history of direct contact with PQ and 16 healthy volunteers were involved in the study. The ELM method is examined based on the metabolites of blood samples determined by gas chromatography coupled with mass spectrometry in terms of classification accuracy, sensitivity, specificity and AUC (area under the receiver operating characteristic (ROC) curve) criterion, respectively. Additionally, the feature selection was also investigated to further boost the performance of ELM and the most influential feature was detected. The experimental results demonstrate that the proposed approach can be regarded as a success with the excellent classification accuracy, AUC, sensitivity and specificity of 91.64%, 0.9156%, 91.33% and 91.78%, respectively. Promisingly, the proposed method might serve as a new candidate of powerful tools for diagnosis of PQ-poisoned patients with excellent performance.

Clearance rate and BP-ANN model in paraquat poisoned patients treated with hemoperfusion

In order to investigate the effect of hemoperfusion (HP) on the clearance rate of paraquat (PQ) and develop a clearance model, 41 PQ-poisoned patients who acquired acute PQ intoxication received HP treatment. PQ concentrations were determined by high performance liquid chromatography (HPLC). According to initial PQ concentration, study subjects were divided into two groups: Low-PQ group (0.05–1.0 μg/mL) and High-PQ group (1.0–10 μg/mL). After initial HP treatment, PQ concentrations decreased in both groups. However, in the High-PQ group, PQ levels remained in excess of 0.05 μg/mL and increased when the second HP treatment was initiated. Based on the PQ concentrations before and after HP treatment, the mean clearance rate of PQ calculated was 73 ± 15%. We also established a backpropagation artificial neural network (BP-ANN) model, which set PQ concentrations before HP treatment as input data and after HP treatment as output data. When it is used to predict PQ concentration after HP treatment, high prediction accuracy (R = 0.9977) can be obtained in this model. In conclusion, HP is an effective way to clear PQ from the blood, and the PQ concentration after HP treatment can be predicted by BP-ANN model.

Early haemoperfusion with continuous venovenous haemofiltration improves survival of acute paraquat-poisoned patients

Objective

To determine whether haemoperfusion (HP) with continuous venovenous haemofiltration (CVVH) improves the survival of patients with acute paraquat poisoning, compared with those treated using HP alone.

Methods

Medical records of patients with acute paraquat poisoning were analysed. Patients were randomised to undergo HP or HP + CVVH within 24 h of paraquat ingestion. Mortality rate, survival duration and cause of death were recorded.

Results

There were no significant differences in mortality rate between the HP group ( n = 458) and the HP + CVVH group ( n = 226) (57.4% and 58.4%, respectively). The mean survival duration was significantly longer in the HP + CVVH group than the HP group (8.6 ± 3.1 and 5.1 ± 2.3 days, respectively). Early circulatory collapse was a major cause of death in the HP group. The major cause of death in the HP + CVVH group was late respiratory failure.

Conclusion

Combined therapy with HP and CVVH can prevent early death and prolong survival duration following acute paraquat poisoning, providing the opportunity for further treatment.

Comparison between kidney and continuous plasma perfusion for paraquat elimination

BACKGROUND

Thousands of paraquat (PQ)-poisoned patients continue to die. Plasma perfusion (PP) has recently been incorporated as a method of clinical detoxification. The purpose of this study was to estimate the PQ clearance of PP and observe the effect of PP on PQ concentration in the blood of patients with acute PQ poisoning.

METHODS

Twenty one PQ-poisoned patients admitted to our poisoning center within 24 hours after the ingestion were prospectively enrolled. Continuous plasma perfusion was performed. Urinary PQ and plasma PQ concentration level at inlet/outlet of the cartridge were obtained right before and 1.5 hours after the start of each perfusion session for the calculation of renal and plasma PQ excretion.

RESULTS

In all 8 rounds (108 sessions) of PP on the 21 patients, PQ clearance rate (mL/min) by PP was always found to be higher than the renal value: (1st 11.14 ± 6.13 versus 6.53 ± 1.46; 2nd 18.36 ± 11.32 versus 6.23 ± 1.51; 3rd 16.13 ± 10.05 versus 4.01 ± 0.93; 4th 12.86 [6.72, 17.47] versus 2.42 [0.65, 4.20]; 5th 14.12 [10.48, 35.20] versus 1.77 [0.63, 2.91]; 6th 16.47 [11.82; 20.69] versus 1.70 [0.23, 3.18]; 7th 13.33 [9.71, 18.75] versus 1.10 [0.14, 2.99]; 8th 11.27 [9.21, 16.02] versus 1.10 [0.09, 2.79], P < 0.05). The survivors showed a higher plasma PQ reduction rate (mg L hour) than the nonsurvivors (0.57 ± 0.03 versus 0.47 ± 0.06, P < 0.05).

CONCLUSIONS

Our data show that PP therapies help in the clearance of PQ and may prove a promising therapeutic tool in patients with acute PQ intoxication.

Demographics, clinical characteristics and management of herbicide poisoning in tertiary care hospital

Herbicide poisoning is most common method of suicide in India and it is associated with high morbidity and mortality. Among different herbicidal poisonings the most predominantly found poisonings are paraquat and glyphosate. These compounds are highly toxic and their poisonings require proper management techniques. High fatality is seen in these cases which are mainly due to its inherent toxicity and lack of effective treatment. Common symptoms of these poisonings includes gastrointestinal corrosive effects with mouth and throat, epigastric pain and dysphagia, acid-base imbalance, pulmonary edema, shock and arrhythmia. Long term health effects include pulmonary fibrosis, renal failure, hepatic failure, heart failure, multi-organ failure or death. No proven antidote exists for these poisonings. So the treatment is mainly supportive. Initially gastric lavage or whole-gut irrigation using adsorbents such as Fuller's earth, bentonite or activated charcoal is recommended. In case of renal failure hemodialysis or hemoperfusion may be considered. However novel approaches like treatment with N-acetylcysteine, vitamin C, vitamin E, cyclophosphamide may also be helpful.

Glucocorticoid with cyclophosphamide for paraquat-induced lung fibrosis

BACKGROUND

Paraquat is an effective and widely used herbicide but is also a lethal poison. In many developing countries paraquat is widely available and inexpensive, making poisoning prevention difficult. However most of the people who become poisoned from paraquat have taken it as a means of suicide.Standard treatment for paraquat poisoning both prevents further absorption and reduces the load of paraquat in the blood through haemoperfusion or haemodialysis. The effectiveness of standard treatments is extremely limited.The immune system plays an important role in exacerbating paraquat-induced lung fibrosis. Immunosuppressive treatment using glucocorticoid and cyclophosphamide in combination is being developed and studied.

OBJECTIVES

To assess the effects of glucocorticoid with cyclophosphamide on mortality in patients with paraquat-induced lung fibrosis.

SEARCH METHODS

The most recent search was run on the 15th April 2014. We searched the Cochrane Injuries Group's Specialised Register, The Cochrane Library, Ovid MEDLINE(R), Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily and Ovid OLDMEDLINE(R), Embase Classic+Embase (Ovid), ISI WOS (SCI-EXPANDED, SSCI, CPCI-S & CPSI-SSH), trials registries, Chinese databases (, , ) and reference lists.

SELECTION CRITERIA

RCTs were included in this review. All patients were to receive standard care, plus the intervention or control. The intervention was glucocorticoid with cyclophosphamide in combination versus a control of a placebo, standard care alone or any other therapy in addition to standard care.

DATA COLLECTION AND ANALYSIS

The mortality risk ratio (RR) and 95% confidence interval (CI) was calculated for each study on an intention-to-treat basis. Data for all-cause mortality at final follow-up were summarised in a meta-analysis using a fixed-effect model.

MAIN RESULTS

This systematic review includes three trials with a combined total of 164 participants who had moderate to severe paraquat poisoning. Patients who received glucocorticoid with cyclophosphamide in addition to standard care had a lower risk of death at final follow-up than those receiving standard care only (RR 0.72; 95% CI 0.59 to 0.89).

AUTHORS' CONCLUSIONS

Based on the findings of three small RCTs of moderate to severely poisoned patients, glucocorticoid with cyclophosphamide in addition to standard care may be a beneficial treatment for patients with paraquat-induced lung fibrosis. To enable further study of the effects of glucocorticoid with cyclophosphamide for patients with moderate to severe paraquat poisoning, hospitals may provide this treatment as part of an RCT with allocation concealment.

AMP-activated protein kinase deficiency rescues paraquat-induced cardiac contractile dysfunction through an autophagy-dependent mechanism

AIM

Paraquat, a quaternary nitrogen herbicide, is a highly toxic prooxidant resulting in multi-organ failure including the heart although the underlying mechanism still remains elusive. This study was designed to examine the role of the cellular fuel sensor AMP-activated protein kinase (AMPK) in paraquat-induced cardiac contractile and mitochondrial injury.

RESULTS

Wild-type and transgenic mice with overexpression of a mutant AMPK α2 subunit (kinase dead, KD), with reduced activity in both α1 and α2 subunits, were administered with paraquat (45 mg/kg) for 48 h. Paraquat elicited cardiac mechanical anomalies including compromised echocardiographic parameters (elevated left ventricular end-systolic diameter and reduced factional shortening), suppressed cardiomyocyte contractile function, intracellular Ca(2+) handling, reduced cell survival, and overt mitochondrial damage (loss in mitochondrial membrane potential). In addition, paraquat treatment promoted phosphorylation of AMPK and autophagy. Interestingly, deficiency in AMPK attenuated paraquat-induced cardiac contractile and intracellular Ca(2+) derangement. The beneficial effect of AMPK inhibition was associated with inhibition of the AMPK-TSC-mTOR-ULK1 signaling cascade. In vitro study revealed that inhibitors for AMPK and autophagy attenuated paraquat-induced cardiomyocyte contractile dysfunction.

CONCLUSION

Taken together, our findings revealed that AMPK may mediate paraquat-induced myocardial anomalies possibly by regulating the AMPK/mTOR-dependent autophagy.

Survival predictors in paraquat intoxification and role of immunosuppression

Paraquat poisoning resulted in multiorgan failure and is associated with high mortality. We audited 83 historical cases of paraquat poisoning in past 2 years treated with conventional decontamination and supportive treatment, followed by enrolling 85 patients over a 2 year period into additional immunosuppression with intravenous (i.v.) methylprednisolone and i.v. cyclophosphamide.

Our results showed that age, poor renal function and leucocytosis are the main predictors of fatal outcome. Immunosuppression regime rendered higher survival (6 out of 17 patients (35.3%)) versus historical control (1 out of 18 patients (5.6%)) (p = 0.041) in the cohort with admission eGFR < 50 ml/min/1.73 m² and WBC count > 11,000/μL.

In contrast, there was no difference in survival with immunosuppression regime (38 out of 64 patients (59.4%)) compared to historical control (30 out of 52 patients (57.7%)) (p = 0.885) in those with eGFR > 50 ml/min/1.73 m² or WBC < 11,000/μL at presentation.

Multivariable logistic regression showed survival probability = exp(logit)/(1 + exp(logit)), in which logit = 13.962 − (0.233 × ln(age (year))) − (1.344 × ln(creatinine (μmol/L))) − (1.602 × ln(rise in creatinine (μmol/day))) – (0.614 × ln(WBC (,000/μL))) + (2.021 × immunosuppression) and immunosuppression = 1 if given and 0 if not. Immunosuppression therapy yielded odds ratio of 0.132 (95% confidential interval: 0.029–0.603, p = 0.009).

In conclusion, immunosuppression therapy with intravenous methylprednisolone and cyclophosphamide may counteract immune mediated inflammation after paraquat poisoning and improve survival of patients with admission eGFR < 50 ml/min/1.73 m² and WBC count > 11,000/μL.

Paraquat poisoning: A case report and review of literature

Paraquat (1, r-dimethyl-4,4’-bipyridium dichloride), a brown syrupy liquid is an effective herbicide that has low chronic toxicity because of its rapid deactivation on contact with soil. A high dose of paraquat or severe poisoning has a poor prognosis. At present there is no specific antidote to paraquat poisoning, hence the need to focus on prevention and in case of exposure or ingestion, aggressive decontamination to prevent further absorption. Although uncommon, paraquat ingestion can lead to severe and often fatal toxicity. However, despite its widespread availability, reports of this herbicide poisoning in India are uncommon.

Addition of immunosuppressive treatment to hemoperfusion is associated with improved survival after paraquat poisoning: a nationwide study

Paraquat poisoning associates very high mortality rate. Early treatment with hemoperfusion is strongly suggested by animal and human studies. Although the survival benefit of additional immunosuppressive treatment (IST) in combination with hemoperfusion is also reported since 1971, the large-scale randomized control trials to confirm the effects of IST is difficult to be executed. Therefore, we designed this nationwide large-scale population-based retrospective cohort study to investigate the outcome of paraquat poisoning with hemoperfusion and the additional effects of IST combined with hemoperfusion. This nationwide retrospective cohort study utilized data retrieved from the National Health Insurance Research Database (NHIRD) of Taiwan. A total of 1811 hospitalized patients with a diagnosis of paraquat poisoning who received hemoperfusion between 1997 and 2009 were enrolled. The mean age of all 1811 study subjects was 47.3 years. 70% was male. The overall survival rate was only 26.4%. Respiratory failure and renal failure were diagnosed in 56.2% and 36% patients. The average frequency of hemoperfusion was twice. IST was added in 42.2% patients. IST significantly increases survival rate (from 24.3% to 29.3%, P<0.001). The combined IST with methylprednisolone, cyclophosphamide and dexamethasone associates with the highest survival rate (48%, P<0.001). Moreover, patients younger than 45 years of age in the IST group had the best survival (41.0% vs. 33.7%, p<0.001). Our results support the use of IST with hemoperfusion for paraquat-poisoned patients. The best survival effect of IST is the combination of methylprednisolone, cyclophosphamide and daily dexamethasone, especially in patients with younger age.

Redox-sensitive glycogen synthase kinase 3β-directed control of mitochondrial permeability transition: rheostatic regulation of acute kidney injury

Mitochondrial dysfunction plays a pivotal role in necroapoptotic cell death and in the development of acute kidney injury (AKI). Evidence suggests that glycogen synthase kinase (GSK) 3β resides at the nexus of multiple signaling pathways implicated in the regulation of mitochondrial permeability transition (MPT). In cultured renal tubular epithelial cells, a discrete pool of GSK3β was detected in mitochondria. Coimmunoprecipitation assay confirmed that GSK3β physically interacts with cyclophilin F and voltage-dependent anion channel (VDAC), key MPT regulators that possess multiple GSK3β phosphorylation consensus motifs, suggesting that GSK3β has a direct control of MPT. Upon a strong burst of reactive oxygen species elicited by the pro-oxidant herbicide paraquat, the activity of the redox-sensitive GSK3β was drastically enhanced. This was accompanied by augmented phosphorylation of cyclophilin F and VDAC, associated with MPT and cell death. Inhibition of GSK3β by either the selective inhibitor 4-Benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8) or forced expression of a kinase-dead mutant obliterated paraquat-induced phosphorylation of cyclophilin F and VDAC, prevented MPT, and improved cellular viability. Conversely, ectopic expression of a constitutively active GSK3β amplified the effect of paraquat on cyclophilin F and VDAC phosphorylation and sensitized cells to paraquat-induced MPT and death. In vivo, paraquat injection elicited marked oxidant stress in the kidney and resulted in acute kidney dysfunction and massive tubular apoptosis and necrosis. Consistent with in vitro findings, the activity of GSK3β was augmented in the kidney after paraquat injury, associated with increased phosphorylation of cyclophilin F and VDAC and sensitized MPT. TDZD-8 blocked GSK3β activity in the kidney, intercepted cyclophilin F and VDAC phosphorylation, prevented MPT, attenuated tubular cell death, and ameliorated paraquat-induced AKI. Our data suggest that the redox-sensitive GSK3β regulates renal tubular injury in AKI by controlling the activity of MPT regulators.

Paraquat poisoning induces TNF-α-dependent iNOS/NO mediated hyporesponsiveness of the aorta to vasoconstrictors in rats

Paraquat is a toxic herbicide that may induce acute lung injury, circulatory failure and death. The present work aimed at investigating whether there is systemic inflammation and vascular dysfunction after paraquat exposure and whether these parameters were related. There was neutrophilia and accumulation of neutrophils in lung and bronchoalveolar lavage of animals given paraquat. This was associated with an increase in serum levels of TNF-α. In rats given paraquat, the relaxant response of aortic rings to acetylcholine was not modified but the contractile response to phenylephrine was greatly reduced. Endothelium removal or treatment with non-selective (L-NAME) or selective (L-NIL) inhibitors of inducible nitric oxide synthase (iNOS) restored contraction of aortas. There was greater production of nitric oxide (NO), which was restored to basal level by L-NIL, and greater expression of iNOS in endothelial cells, as seen by Western blot analyses and confocal microscopy. Blockade of TNF-α reduced pulmonary and systemic inflammation and vascular dysfunction. Together, our results clearly show that paraquat causes pulmonary and systemic inflammation, and vascular dysfunction in rats. Vascular dysfunction is TNF-α dependent, associated with enhanced expression of iNOS in aortic endothelial cells and greater NO production, which accounts for the decreased responsiveness of aortas to vasoconstrictors. Blockers of TNF-α may be useful in patients with paraquat poisoning.

Tissue concentration of paraquat on day 32 after intoxication and failed bridge to transplantation by extracorporeal membrane oxygenation therapy

Background

Paraquat is a highly toxic herbicide, which not only leads to acute organ damage, but also to pulmonary fibrosis. There are only anecdotal reports of rescue lung transplantation, as paraquat is stored and only slowly released from different tissues. Bridging the time to complete depletion of paraquat from the body could render this exceptional therapy strategy possible, but not much is known on the time interval after which transplantation can safely be performed.

Case presentation

We report on a case of accidental paraquat poisoning in a 23 years old Caucasian man, who developed respiratory failure due to pulmonary fibrosis. The patient was listed for high urgency lung transplantion, and extracorporeal membrane oxygenation was implemented to bridge the time to transplantation. The patient died 32 days after paraquat ingestion, before a suitable donor organ was found. In postmortem tissue specimen, no paraquat was detectable anymore.

Conclusion

This case report indicates that complete elimination of paraquat after oral ingestion of a lethal dose is achievable. The determined time frame for this complete elimination might be relevant for patients, in which lung transplantation is considered.

Amelioration of Paraquat-Induced Pulmonary Injury by Mesenchymal Stem Cells

Acute paraquat (PQ) poisoning induces redox cycle and leads to fatal injury of lung. Clinical management is supportive in nature due to lack of effective antidote, and the mortality is very high. Mesenchymal stem cells (MSCs) process the properties of immunomodulation, anti-inflammatory, and antifibrotic effects and oxidative stress resistance. MSC transplantation may theoretically serve as an antidote in PQ intoxication. In this study, we examined the potential therapeutic effects of MSCs in PQ-induced lung injury. The degree of PQ toxicity in the rat type II pneumocyte cell line, L2, and MSCs was evaluated by examining cell viability, ultrastructural changes, and gene expression. L2 cells treated with 0.5 mM PQ were cocultured in the absence or presence of MSCs. For the in vivo study, adult male SD rats were administered an intraperitoneal injection of PQ (24 mg/kg body weight) and were divided into three groups: group I, control; group II, cyclophosphamide and methylprednisolone; group III, MSC transplantation 6 h after PQ exposure. MSCs were relatively resistant to PQ toxicity. Coculture with MSCs significantly inhibited PQ accumulation in L2 cells and upregulated the expression of antioxidative heme oxygenase 1 and metallothionein 1a genes, reversed epithelial-to-mesenchymal transition, and increased the viability of PQ-exposed L2 cells. Treatment with MSCs resulted in a significant reduction in severity of liver and renal function deterioration, alleviated lung injury, and prolonged the life span of rats. Altogether, our results suggest that MSCs possess antidote-like effect through multifactorial protection mechanism. The results of this preclinical study demonstrate that transplantation of MSCs may be a promising therapy and should be further validated clinically.

Xuebijing for paraquat poisoning

BACKGROUND

At present, there is a lack of effective treatments for paraquat poisoning. Xuebijing injection is a complex traditional Chinese prescription consisting of Flos Carthami, Radix Paeoniae Rubra, Rhizoma Chuanxiong, Radix Salviae Miltiorrhizae and Radix Angelicae Sinensis. Although clinical experience suggests that Xuebijing injection might have potential in the management of paraquat poisoning, there is no conclusion on the effectiveness of this treatment.

OBJECTIVES

To assess the effects of Xuebijing injection in patients with paraquat poisoning.

SEARCH METHODS

We searched the Cochrane Injuries Group's Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE (OvidSP), EMBASE (OvidSP), CINAHL (EBSCO), ISI Web of Science: Science Citation Index Expanded, ISI Web of Science: Conference Proceedings Citation Index-Science, Chinese bio-medical literature and retrieval system (CBM), China National Knowledge Infrastructure Database (CNKI), and the Traditional Chinese Medicine Database. The search was run on the 29th May 2013.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing Xuebijing injection combined with conventional care against conventional care alone.

DATA COLLECTION AND ANALYSIS

Two or three authors independently selected studies, assessed study quality and extracted data. We calculated the mortality risk ratio (RR) and 95% confidence interval (CI). Data on all-cause mortality at the end of follow-up were summarised in a meta-analysis.

MAIN RESULTS

We identified two trials including 84 people. Although there were fewer deaths in people treated with Xuebijing injection, meta-analysis showed that it did not provide a statistically significant benefit in reducing all-cause mortality in people with paraquat poisoning as compared to control (RR 0.71; 95% CI 0.48 to 1.04; P = 0.08).

AUTHORS' CONCLUSIONS

Based on the findings of two small RCTs, Xuebijing injection did not have a statistically significant benefit on reducing all-cause mortality in people with paraquat poisoning. However, both included studies involved small numbers of participants and were considered to be of poor methodological quality. The results are imprecise and easily compatible with the play of chance. Xuebijing injection may be effective for people with paraquat poisoning; however, this needs to be proven by further high-quality evidence.

Vitamin E ameliorates the decremental effect of paraquat on cardiomyocyte contractility in rats

Background

Exposure to pesticides and industrial toxins are implicated in cardiovascular disease. Paraquat (PAR) is a toxic chemical widely used as an herbicide in developing countries and described as a major suicide agent. The hypothesis tested here is that PAR induced myocardial dysfunction may be attributed to altered mechanisms of Ca²⁺ transport which are in turn possibly linked to oxidative stress. The mechanisms of PAR induced myocardial dysfunction and the impact of antioxidant protection was investigated in rat ventricular myocytes.

Methodology

Forty adult male Wistar rats were divided into 4 groups receiving the following daily intraperitoneal injections for 3 weeks: Group 1 PAR (10 mg/kg), Control Group 2 saline, Group 3 vitamin E (100 mg/kg) and Group 4 PAR (10 mg/kg) and vitamin E (100 mg/kg). Ventricular action potentials were measured in isolated perfused heart, shortening and intracellular Ca²⁺ in electrically stimulated ventricular myocytes by video edge detection and fluorescence photometry techniques, and superoxide dismutase (SOD) and catalase (CAT) levels in heart tissue.

Principal Findings

Spontaneous heart rate, resting cell length, time to peak (TPK) and time to half (THALF) relaxation of myocyte shortening were unaltered. Amplitude of shortening was significantly reduced in PAR treated rats (4.99±0.26%) and was normalized by vitamin E (7.46±0.44%) compared to controls (7.87±0.52%). PAR significantly increased myocytes resting intracellular Ca²⁺ whilst TPK and THALF decay and amplitude of the Ca²⁺ transient were unaltered. The fura-2–cell length trajectory during the relaxation of the twitch contraction was significantly altered in myocytes from PAR treated rats compared to controls suggesting altered myofilament sensitivity to Ca²⁺ as it was normalized by vitamin E treatment. A significant increase in SOD and CAT activities was observed in both PAR and vitamin E plus PAR groups.

Conclusions

PAR exposure compromised rats heart function and ameliorated by vitamin E treatment.

Relationship between hepatic dysfunction and prognosis in patients with paraquat poisoning: Clinical effects of hemopurification therapy

AIM: To investigate the relationship between hepatic dysfunction and prognosis in patients with paraquat poisoning, and to assess the clinical effects of hemopurification therapy [hemoperfusion (HP), continuous venovenous hemodiafiltration (CVVHDF), plasma exchange (PE)] in these patients.

METHODS: The clinical data for 55 patients with paraquat poisoning who were treated at EICU in our hospital from January 2009 to October 2012 were analyzed retrospectively. The patients were divided into two groups, death group and survival group. ALT, AST, TBIL and DBIL were measured on the 1st, 4th, 7th and 14th day after poisoning. The patients were then divided into two groups according to the use of CVVHDF therapy or not to evaluate the effect of this treatment on hepatic function.

RESULTS: At each time point, the levels of all the hepatic function parameters in the death group were significantly higher than those in the survival group (all P < 0.05). HP was performed in all patients. Two patients who received PE treatment were dead. The mortality in the CVVHDF group was significantly higher than that in the non-CVVHDF group (P < 0.01), and there was no significant difference for all liver function parameters at each time point between the CVVHDF group and non-CVVHDF group.

CONCLUSION: Paraquat poisoning can cause hepatic dysfunction. The changes in liver function parameters, especially high bilirubin, might be reliable predictors of prognosis. Hemopurification therapy, especially CVVHDF, is useless in patients with paraquat poisoning in terms of improving liver function and decreasing mortality.

Early hemoperfusion may improve survival of severely paraquat-poisoned patients

BACKGROUND

Thousands of paraquat (PQ)-poisoned patients continue to die, particularly in developing countries. Although animal studies indicate that hemoperfusion (HP) within 2-4 h after intoxication effectively reduces mortality, the effect of early HP in humans remains unknown.

METHODS

We analyzed the records of all PQ-poisoned patients admitted to 2 hospitals between 2000 and 2009. Patients were grouped according to early or late HP and high-dose (oral cyclophosphamide [CP] and intravenous dexamethasone [DX]) or repeated pulse (intravenous methylprednisolone [MP] and CP, followed by DX and repeated MP and/or CP) PQ therapy. Early HP was defined as HP <4 h, and late HP, as HP ≥ 4 h after PQ ingestion. We evaluated the associations between HP <4 h, <5 h, <6 h, and <7 h after PQ ingestion and the outcomes. Demographic, clinical, laboratory, and mortality data were analyzed.

RESULTS

The study included 207 severely PQ-poisoned patients. Forward stepwise multivariate Cox hazard regression analysis showed that early HP <4 h (hazard ratio [HR] = 0.38, 95% confidence interval (CI) 0.16-0.86; P = 0.020) or HP <5 h (HR = 0.60, 95% CI: 0.39-0.92; P = 0.019) significantly decreased the mortality risk. Further analysis showed that early HP reduced the mortality risk only in patients treated with repeated pulse therapy (n = 136), but not high-dose therapy (n = 71). Forward stepwise multivariate Cox hazard regression analysis showed that HP <4.0 h (HR = 0.19, 95% CI: 0.05-0.79; P = 0.022) or <5.0 h (HR = 0.49, 95% CI: 0.24-0.98; P = 0.043) after PQ ingestion significantly decreased the mortality risk in repeated pulse therapy patients, after adjustment for relevant variables.

CONCLUSION

The results showed that early HP after PQ exposure might be effective in reducing mortality in severely poisoned patients, particularly in those treated with repeated pulse therapy.

Glucocorticoid with cyclophosphamide for paraquat-induced lung fibrosis

BACKGROUND

Paraquat is an effective and widely used herbicide but is also a lethal poison. In many developing countries paraquat is widely available and inexpensive, making poisoning prevention difficult. However most of the people who become poisoned from paraquat have taken it as a means of suicide.Standard treatment for paraquat poisoning both prevents further absorption and reduces the load of paraquat in the blood through haemoperfusion or haemodialysis. The effectiveness of standard treatments is extremely limited.The immune system plays an important role in exacerbating paraquat-induced lung fibrosis. Immunosuppressive treatment using glucocorticoid and cyclophosphamide in combination is being developed and studied.

OBJECTIVES

To assess the effects of glucocorticoid with cyclophosphamide on mortality in patients with paraquat-induced lung fibrosis.

SEARCH METHODS

To identify randomised controlled trials (RCTs) on this topic, we searched the Cochrane Injuries Group's Specialised Register (searched 1 February 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 1), MEDLINE (Ovid SP) (1946 January Week 3 2012), EMBASE (Ovid SP) (1947 to Week 4 2012), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED) (1970 to January 2012), ISI Web of Science: Conference Proceedings Citation Index - Science (CPCI-S) (1990 to January 2012), Chinese Biomedical Literature and Retrieval System (CBM) (1978 to April 2012), Chinese Medical Current Contents (CMCC) (1995 to April 2012), and Chinese Medical Academic Conference (CMAC) (1994 to April 2012). Searches were completed on English language databases on 1 February 2012 and on Chinese language databases on 12 April 2012.

SELECTION CRITERIA

RCTs were included in this review. All patients were to receive standard care, plus the intervention or control. The intervention was glucocorticoid with cyclophosphamide in combination versus a control of a placebo, standard care alone or any other therapy in addition to standard care.

DATA COLLECTION AND ANALYSIS

The mortality risk ratio (RR) and 95% confidence interval (CI) was calculated for each study on an intention-to-treat basis. Data for all-cause mortality at final follow-up were summarised in a meta-analysis using a fixed-effect model.

MAIN RESULTS

This systematic review includes three trials with a combined total of 164 participants who had moderate to severe paraquat poisoning. Patients who received glucocorticoid with cyclophosphamide in addition to standard care had a lower risk of death at final follow-up than those receiving standard care only (RR 0.72; 95% CI 0.59 to 0.89).

AUTHORS' CONCLUSIONS

Based on the findings of three small RCTs of moderate to severely poisoned patients, glucocorticoid with cyclophosphamide in addition to standard care may be a beneficial treatment for patients with paraquat-induced lung fibrosis. To enable further study of the effects of glucocorticoid with cyclophosphamide for patients with moderate to severe paraquat poisoning, hospitals may provide this treatment as part of an RCT with allocation concealment.

Medical management of paraquat ingestion

Poisoning by paraquat herbicide is a major medical problem in parts of Asia while sporadic cases occur elsewhere. The very high case fatality of paraquat is due to inherent toxicity and lack of effective treatments. We conducted a systematic search for human studies that report toxicokinetics, mechanisms, clinical features, prognosis and treatment. Paraquat is rapidly but incompletely absorbed and then largely eliminated unchanged in urine within 12-24 h. Clinical features are largely due to intracellular effects. Paraquat generates reactive oxygen species which cause cellular damage via lipid peroxidation, activation of NF-κB, mitochondrial damage and apoptosis in many organs. Kinetics of distribution into these target tissues can be described by a two-compartment model. Paraquat is actively taken up against a concentration gradient into lung tissue leading to pneumonitis and lung fibrosis. Paraquat also causes renal and liver injury. Plasma paraquat concentrations, urine and plasma dithionite tests and clinical features provide a good guide to prognosis. Activated charcoal and Fuller's earth are routinely given to minimize further absorption. Gastric lavage should not be performed. Elimination methods such as haemodialysis and haemoperfusion are unlikely to change the clinical course. Immunosuppression with dexamethasone, cyclophosphamide and methylprednisolone is widely practised, but evidence for efficacy is very weak. Antioxidants such as acetylcysteine and salicylate might be beneficial through free radical scavenging, anti-inflammatory and NF-κB inhibitory actions. However, there are no published human trials. The case fatality is very high in all centres despite large variations in treatment.

[Paraquat poisoning. Case report and overview]

Paraquat poisoning in Germany is rare. Because plasma levels do not necessarily match the ingested amount of paraquat, repeated measurement of plasma levels is imperative. There is a large potential in the prehospital phase to improve prognosis: further resorption must be terminated by rigorous charcoal administration and early tracheal intubation if necessary. Because paraquat can be resorbed by dermal contact, steps to ensure sufficient protection of emergency medical personnel must be taken.As soon as further resorption has been prevented sufficiently, forced diuresis, renal replacement therapy, and hemoperfusion can be of help, but still remain controversial. To reduce pulmonary fibrosis, inspiratory oxygen concentrations must be adjusted to the minimal amount needed to ensure satisfactory tissue oxygenation. Data supporting the advantageous use of cyclophosphamide combined with methylprednisolone for the treatment of pulmonary fibrosis were recently published. Since the toxic mechanism implies a mismatch of oxidants and anti-oxidants, co-administration of ascorbic acid and N-acetylcysteine are simple treatments with few side effects.

Blood purification in toxicology: nephrology's ugly duckling

Contrary to popular opinion, application of extracorporeal therapies for poisonings predates their use for ESRD. Despite this observation, the science of blood purification in toxicology remains desperately stagnant today. In fact, much of our current knowledge is derived from George Schreiner's 1958 review. Original publications are almost exclusively composed of case reports and case series, from which good inference is impossible. Until randomized controlled trials become available, the medical community would be well served by a group mandated to systematically review available literature, extract relevant information, provide recommendations based on current evidence, and propose research initiatives. The EXtracorporeal TReatments In Poisoning workgroup, formed by several international experts in different medical fields and represented by over 20 societies, now has this mission.