Predictors of acute kidney injury after paraquat intoxication

The prediction of in-hospital mortality in elderly patients with sepsis-associated acute kidney injury utilizing machine learning models

Background

Sepsis-associated acute kidney injury (SA-AKI) is a severe complication associated with poorer prognosis and increased mortality, particularly in elderly patients. Currently, there is a lack of accurate mortality risk prediction models for these patients in clinic.

Objectives

This study aimed to develop and validate machine learning models for predicting in-hospital mortality risk in elderly patients with SA-AKI.

Methods

Machine learning models were developed and validated using the public, high-quality Medical Information Mart for Intensive Care (MIMIC)-IV critically ill database. The recursive feature elimination (RFE) algorithm was employed for key feature selection. Eleven predictive models were compared, with the best one selected for further validation. Shapley Additive Explanations (SHAP) values were used for visualization and interpretation, making the machine learning models clinically interpretable.

Results

There were 16,154 patients with SA-AKI in the MIMIC-IV database, and 8426 SA-AKI patients were included in this study (median age: 77.0 years; female: 45%). 7728 patients excluded based on these criteria. They were randomly divided into a training cohort (5,934, 70%) and a validation cohort (2,492, 30%). Nine key features were selected by the RFE algorithm. The CatBoost model achieved the best performance, with an AUC of 0.844 in the training cohort and 0.804 in the validation cohort. SHAP values revealed that AKI stage, PaO2, and lactate were the top three most important features contributing to the CatBoost model.

Conclusion

We developed a model capable of predicting the risk of in-hospital mortality in elderly patients with SA-AKI.

An ecological study regarding the association between paraquat exposure and end stage renal disease

BACKGROUND

Persons who experience paraquat poisoning rapidly develop damage to a variety of organ systems including acute kidney injury (AKI), the occurrence of which is associated with an increased risk of death. However, little is known about the effects of chronic paraquat exposure on renal function and the onset of chronic renal disease. The objective of the current study is to assess the association between paraquat exposure and the incidence of end stage renal disease (ESRD) in the United States.

METHODS

Data on the incidence of ESRD for the period 2010 through 2017 and kilograms of paraquat use per square mile for each county in the conterminous United States was obtained from the United States Renal Data System (USRDS) and the National Water Quality Assessment (NAWQA) Program, respectively. Negative binomial regression was used to estimate rate ratios (RRs) and 95% confidence intervals (CIs) for the association between quartiles of paraquat exposure and the incidence of ESRD.

RESULTS

The incidence of ESRD increased with increasing paraquat density. Based on a 20-year exposure lag, those in the highest paraquat density quartile had a 21% higher rate of ESRD compared to the lowest quartile whereas for a 15-year lag the increase was 26%. Adjusted associations were attenuated though still followed an increasing linear trend across quintiles.

CONCLUSIONS

The results of this study are consistent with a large number of studies documenting a high incidence of AKI and a small number of studies chronic renal disease following acute and chronic paraquat exposure, respectively. While the pathophysiological mechanisms underlying kidney injury following paraquat poisoning are well understood, more research is necessary to understand the natural history of chronic kidney disease due to chronic paraquat exposure.

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.

Potential Mechanisms Involved in Chronic Kidney Disease of Unclear Etiology

BACKGROUND AND OBJECTIVES

The etiology of chronic kidney disease of unclear etiology, also known as Mesoamerican nephropathy, remains unclear. We investigated potential etiologies for Mesoamerican nephropathy in an immigrant dialysis population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Migrants with Mesoamerican nephropathy kidney failure (n=52) were identified by exclusion of known causes of kidney disease and compared using a cross-sectional survey with demographically similar patients with kidney failure from other causes (n=63) and age/sex/place of origin-matched healthy participants (n=16). Survey results were extended to the bench; C57BL/6 mice (n=73) received 10-15 weekly intraperitoneal injections of paraquat (a reactive oxygen species-generating herbicide) or vehicle. Kidney function, histology, and expression of organic cation transporter-2 (proximal tubule entry for paraquat) and multidrug and toxin extrusion 1 (extrusion pathway) were examined. Kidney biopsies from Nicaraguan patients with acute Mesoamerican nephropathy were stained for the above transporters and compared with patients with tubulointerstitial nephritis and without Mesoamerican nephropathy.

RESULTS

Patients with Mesoamerican nephropathy and kidney failure were young agricultural workers, almost exclusively men; the majority were from Mexico and El Salvador; and they had prior exposures to agrochemicals, including paraquat (27%). After adjustment for age/sex, exposure to any agrochemical or paraquat was associated with Mesoamerican nephropathy kidney failure (odds ratio, 4.86; 95% confidence interval, 1.82 to 12.96; P=0.002 and odds ratio, 12.25; 95% confidence interval, 1.51 to 99.36; P=0.02, respectively). Adjusted for age/sex and other covariates, 1 year of agrochemical exposure was associated with Mesoamerican nephropathy kidney failure (odds ratio, 1.23; 95% confidence interval, 1.04 to 1.44; P=0.02). Compared with 16 matched healthy controls, Mesoamerican nephropathy kidney failure was significantly associated with exposure to paraquat and agrochemicals. Paraquat-treated male mice developed kidney failure and tubulointerstitial nephritis consistent with Mesoamerican nephropathy. Organic cation transporter-2 expression was higher in male kidneys versus female kidneys. Paraquat treatment increased organic cation transporter-2 expression and decreased multidrug and toxin extrusion 1 expression in male kidneys; similar results were observed in the kidneys of Nicaraguan patients with Mesoamerican nephropathy.

CONCLUSIONS

Exposure to agrochemicals is associated with Mesoamerican nephropathy, and chronic exposure of mice to paraquat, a prototypical oxidant, induced kidney failure similar to Mesoamerican nephropathy.

Paraquat Induces Lung Injury via miR-199-Mediated SET in a Mouse Model

Objective: To explore the molecular mechanism of lung injury caused by paraquat (PQ) poisoning by investigating miR-199-mediated SET.

Methods: A paraquat poisoning model was established in C57BL/6 male mice via intraperitoneal injection of paraquat. The mice were transfected with miR-199 siRNA and or mimic. After 14 days of treatment, pathophysiological changes of the lung were observed and lung tissue was analyzed via Hematoxylin-Eosin staining. The levels of miR-199, SETs, surfactant protein SP-A and SP-B, and inflammatory and oxidative factors were analyzed by qPCR, Western Blot, and ELISA kits.

Results: A acute lung-injury (ALI) model was established using PQ treatment and confirmed with edema of pulmonary endothelium with low electronic density of endothelial cytoplasm, presence of protein-rich fluid, and numerous erythrocytes in alveolar space, concentric figures of damaged tubular myelin, alveolar destruction, and increase in inflammatory cell numbers. Compared with the control group, miR-199 and SET levels were reduced in the PQ-treated group. miR-199 siRNA increased the SET level, inflammatory and oxidative levels, and reduced the levels of SP-A and SP-B, and miR-199 mimic reduced the SET level, inflammatory and oxidative levels, and increased the levels of SP-A and SP-B. PQ treatment reduced miR-199 level.

Conclusion: Paraquat induces ALI by affecting miR-199-mediated SET.

Thunbergia laurifolia aqueous leaf extract ameliorates paraquat-induced kidney injury by regulating NADPH oxidase in rats

We aim to study the antioxidant ability of Thunbergia laurifolia (TL) aqueous leaf extract against PQ-induced kidney injury. Rats were divided into four groups (n = 4 per group): control group, the rats received subcutaneous injection of 1 ml/kg body weight (BW) normal saline; PQ group, the rats received subcutaneous injection of 18 mg/kg BW paraquat dichloride; PQ + TL-low dose (LD) group, the rats received subcutaneous injection of 18 mg/kg BW paraquat dichloride and were orally gavaged with TL leaf extract (100 mg/kg BW); and PQ + TL-high dose (HD) group, the rats received subcutaneous injection of 18 mg/kg BW paraquat dichloride and were orally gavaged with TL leaf extract (200 mg/kg BW). This study analyzed blood urea nitrogen (BUN) and creatinine levels, renal malondialdehyde (MDA) levels, kidney histopathology, mRNA expressions of renal NADPH oxidase (NOX) and protein expressions of renal NOX-1 and NOX-4 using immunohistochemistry. The PQ group showed a significant increase in BUN and creatinine levels, renal MDA level, and a upregulation of the mRNA expression of renal NOX compared with the control group. It also demonstrated mild hydropic degeneration of the tubules. Immunohistochemistry displayed a significant increase in the protein expressions of renal NOX-1 and NOX-4 compared with the control group. TL aqueous leaf extract especially in the high dose group significantly reduced the BUN and creatinine levels, the renal MDA level, and downregulated the mRNA expression of renal NOX and protein expressions of renal NOX-1 and NOX-4 compared with the PQ group. Furthermore, it can improve PQ-induced kidney injury. TL aqueous leaf extract can ameliorate PQ-induced kidney injury by regulating oxidative stress through inhibiting NOX, especially NOX-1 and NOX-4 expressions.

Silymarin protects the rats against paraquat-induced acute kidney injury via Nrf2

BACKGROUND

Paraquat (PQ) poisoning induces severe acute kidney injury and causes extremely high rate of death. In this study, we aimed to investigate the protective effects of silymarin on PQ-induced acute kidney injury and explore the underlying mechanisms.

METHODS

A rat model was established through intraperitoneal injection of PQ. Rats were administrated with saline or silymarin for 3 days. Then, survival rate, physiological parameters, and renal injury score were evaluated. The apoptosis and oxidative stress in kidney tissues were determined through hematoxylin and eosin staining, quantitative reverse transcription polymerase chain reaction, Western blot, and enzyme-linked immunosorbent assays.

RESULTS

Silymarin administration could significantly increase the survival rate of PQ-poisoned rats. It was found that silymarin treatment improved renal function, decreased injury score in kidney tissues, and inhibited the apoptosis and oxidative stress in PQ-induced acute kidney injury through the activating the signaling pathway of Nrf2 and promoting its nuclear translocation.

CONCLUSION

Silymarin exhibited a protective effect against PQ-induced kidney injury, suggesting that treatment with this flavonoid could be a potential therapeutic agent for the treatment of acute kidney injury.

Relationship between acute kidney injury and mortality in poisoning - a systematic review and metanalysis

RATIONALE

Three consensus classifications of acute kidney injury have been published. These are RIFLE (Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease published by the Acute Dialysis Quality Initiative workgroup), AKIN (published by the Acute Kidney Injury Network) and KDIGO (published by the Kidney Disease Improving Global Outcome workgroup). Acute kidney injury has been reported consistently as associated with worsened outcomes. However, toxicant-related acute kidney injury has been excluded from the studies used to validate the classifications of acute kidney injury.

OBJECTIVE

To study whether poisoned patients who develop acute kidney injury, as defined by consensus definitions/classifications, have higher mortality compared to those who did not.

METHODS

Databases were searched from 2004 to 2019 using the following keywords (KDIGO OR "Kidney Disease: Improving Global Outcomes" OR "Kidney Disease Improving Global Outcomes" OR AKIN OR "AKI network" OR "Acute kidney Injury Network" OR ADQI OR RIFLE OR "Acute dialysis quality initiative") AND (intoxication OR poisoning OR overdose OR ingestion) AND (AKI OR kidney OR renal OR ARF). If data were available, we used a random-effects meta-analysis model and Fisher's exact test to compare mortality in patients according to kidney function definitions (acute kidney injury vs not) and stages (stages vs no acute kidney injury), respectively. If data were available, we assessed the correlation between mortality and renal function (no acute kidney injury, risk/stage 1, injury/stage 2 and failure/stage 3) using the Spearman correlation. If available, we collected the results of statistical analyses in studies that have used acute kidney injury to predict mortality.

RESULTS

Study selection. Thirty-three relevant studies were found, 22/33 retrospective studies (67%) and 11/33 prospective studies (33%). Paraquat was the most frequent toxicant involved (13/33, 39%). We found a disparity between studies regarding the timeframe during which mortality was assessed, the temporality of the renal function considered to predict mortality (initial/worst) and the criteria used to define/grade acute kidney injury across studies. Univariate association between acute kidney injury definitions/stages and mortality. Consensus definitions/staging of acute kidney injury were associated with higher mortality, using univariate analyses, in twenty-eight (RIFLE = 7; AKIN = 12; KDIGO = 9) studies included but not in five (AKIN = 4, KDIGO = 1). When available data were pooled, RIFLE (5 studies), AKIN (16 studies) and KDIGO definitions (8 studies) of acute kidney injury were associated with a higher mortality (Log unadjusted Odds ratios [95%-confidence interval], 2.60 [2.23; 2.97], 2.02 [1.48; 2,52] and 3.22 [2,65; 3.78], respectively). However, we found high heterogeneity (I²=54,7%) and publication bias among studies using AKIN. In ten studies with available data, the correlation between renal function (no acute kidney injury, risk/stage 1, injury/stage 2, failure/stage 3) and mortality was significant in 5 studies (RIFLE = 2; AKIN = 3), but not in five studies (RIFLE = 1; AKIN = 3; KDIGO = 1).Multivariate association between acute kidney injury definitions/stages and mortality. The definitions of acute kidney injury were associated with higher mortality in two studies (RIFLE = 2), but not in four studies (AKIN = 1 and KDIGO = 3. The stages of acute kidney injury (including one or more stages) were associated with higher mortality in four (RIFLE = 1, AKIN = 1 and KDIGO = 2).

CONCLUSIONS

All three consensus definitions/classifications were associated independently with increased mortality in poisoning but with disparity between studies reporting acute kidney injury.

Isorhynchophylline ameliorates paraquat-induced acute kidney injury by attenuating oxidative stress and mitochondrial damage via regulating toll-interacting expression

Isorhynchophylline (IRN) is an alkaloid with anti-inflammatory and anti-oxidative activities in cardiovascular and brain diseases, but its role in paraquat (PQ)-induced acute kidney injury (AKI) is yet unknown. The model of PQ-induced AKI in rats was established by intraperitoneal injection of PQ (25 mg/kg). We found that the tail vein injection of IRN (4 mg/kg) significantly increased the survival rate of PQ-intoxicated rats. IRN administration alleviated PQ-induced renal injury and renal dysfunction in rats, as evidenced by decreased apoptosis in renal cortex and reduced serum creatinine, serum BUN, and urine NGAL levels. Furthermore, IRN treatment improved the PQ-triggered oxidative stress in renal cortex by increasing the levels of anti-oxidant indicators (SOD activity, GSH/GSSG ratio, levels of Nrf-2, NQO-1, and HO-1 in renal cortex) and decreasing the levels of oxidative stress indexes (ROS and MDA levels in renal cortex). Interestingly, toll-interacting protein (Tollip), a negative regulator of interleukin 1 receptor associated kinase 1 (IRAK1) phosphorylation, was demonstrated to be increased by IRN injection in the renal cortex of PQ-intoxicated rats. In vitro experiments revealed that IRN protected renal tubular epithelial cells against PQ toxicity through suppressing oxidative stress and mitochondrial damage, and these protective effects were reversed by Tollip shRNA. Collectively, the present study demonstrated that IRN ameliorated PQ-induced AKI by attenuating oxidative stress and mitochondrial damage through upregulating Tollip, which provides new insights into the pathogenesis and treatment of PQ poisoning.

Association between liberal oxygen therapy and mortality in patients with paraquat poisoning: A multi-center retrospective cohort study

Paraquat (N, N'-dimethyl-4, 4'-bipyridinium dichloride, PQ) intoxication is a common cause of lethal poisoning. This study aimed to identify the risk of using liberal oxygen therapy in patients with PQ poisoning. This was a multi-center retrospective cohort study involving four medical institutions in Taiwan. Data were extracted from the Chang Gung Research Database (CGRD) from January 2004 to December 2016. Patients confirmed to have PQ intoxication with a urine PQ concentration ≥ 5 ppm were analyzed. Patients who received oxygen therapy before marked hypoxia (SpO2 ≥ 90%) were defined as receiving liberal oxygen therapy. The association between mortality and patient demographics, blood paraquat concentration (ppm), and liberal oxygen therapy were analyzed. A total of 416 patients were enrolled. The mortality rate was higher in the liberal oxygen therapy group (87.8% vs. 73.7%, P = 0.007), especially in 28-day mortality (adjusted odds ratio [aOR]: 4.71, 95% confidence interval [CI]: 1.533–14.471) and overall mortality (aOR: 5.97, 95% CI: 1.692–21.049) groups. Mortality in patients with PQ poisoning was also associated with age (aOR: 1.04, 95% CI: 1.015–1.073), blood creatinine level (aOR: 1.49, 95% CI: 1.124–1.978), and blood paraquat concentration (ppm) (aOR, 1.51; 95% CI: 1.298–1.766). Unless the evidence of hypoxia (SpO2 < 90%) is clear, oxygen therapy should be avoided because it is associated with increased mortality.

Octreotide alleviates pancreatic damage caused by paraquat in rats by reducing inflammatory responses and oxidative stress

This study explores the efficacy and mechanism by which octreotide (OCT) alleviates paraquat (PQ)-induced pancreatic injury. Twenty-four adult male rats were randomly divided into three groups: the normal control (NC), PQ poisoning, and OCT treatment groups. The PQ-induced pancreatic injury rat model was established by administering PQ (120 mg/kg). Treatment group rats received OCT (8 μg/kg body weight) every 8 h by subcutaneous injection, 1 h after PQ administration. Rats were euthanized 24 h after PQ injection. Serum amylase, lipase, tumor necrosis factor-α, and interleukin-6 levels were markedly increased in the PQ group versus the NC group. In pancreatic tissue, PQ poisoning drastically induced necrosis and increased inflammatory cytokine and oxidative stress marker levels. Compared with the PQ group, OCT reduced pancreatic damage and histological scores, serum amylase, lipase, and inflammatory cytokine levels, as well as oxidative stress. OCT demonstrates protective effects against PQ-induced pancreatic damage through anti-inflammatory and antioxidant actions.

Investigation of simple, objective, and effective indicators for predicting acute paraquat poisoning outcomes

Initial symptoms of paraquat (PQ) toxicity are often not obvious, and the lack of advanced testing equipment and medical conditions in the primary hospital make it difficult to provide early diagnosis and timely treatment. To explore simple, objective, and effective indicators of prognosis for primary clinicians, we retrospectively analyzed acute PQ poisoning in 190 patients admitted to our hospital from 2008 to 2017. Based on their condition at the time of discharge, patients were categorized into either the survival group (n = 71) or the mortality group (n = 119). Age, PQ ingested amount, urinary PQ, urinary protein, white blood cell (WBC), and serum creatinine (Cr) were the key factors associated with the prognosis for PQ poisoning. We identified specific diagnostic thresholds for these key indicators of PQ poisoning: PQ ingested amount (36.50 mL), urinary PQ (semiquantitative result "++"), urinary protein (semiquantitative result "±"), WBC (16.50 × 10⁹/L), and serum Cr (102.10 µmol/L). Combining these five indicators to identify poisoning outcomes was considered objective, accurate, and convenient. When the combined score was <1, the predicted probability of patient death was 6%. When the combined score was ≥3, the predicted probability of patient death was 96%. These findings provide metrics to assist primary clinicians in predicting outcomes of acute PQ poisoning at earlier stages, a basis for administering treatment.

Serum anion gap at admission as a predictor of the survival of patients with paraquat poisoning: A retrospective analysis

Paraquat (PQ) poisoning is associated with high mortality rate. Therefore, an accurate method for predicting the survival of patients with PQ poisoning is required. This study evaluated the value of serum anion gap (AG) at admission in predicting the survival of such patients.Cases of patients with PQ poisoning admitted to Cangzhou Central Hospital between May 2012 and March 2019 were retrospectively analyzed. The patients were classified into survival and nonsurvival groups on the basis of their 90-day prognosis. Correlation analysis, Cox regression analysis, and receiver operating characteristic and Kaplan-Meier curve analyses were performed to assess the value of AG in predicting the 90-day survival of patients with PQ poisoning.Only 44 of the 108 patients with PQ poisoning survived; thus, the 90-day survival was 40.74%. AG levels at admission were significantly higher in nonsurvivors (26.53 ± 4.93 mmol/L) than in survivors (20.88 ± 2.74 mmol/L) (P < .001) and negatively correlated with 90-day survival (r = -0.557; P < .001). Cox regression analysis revealed that AG at admission is an independent prognostic marker of the 90-day survival of patients with PQ poisoning. AG level at admission had an area under the receiver operating characteristic curve of 0.836 (95% confidence interval: 0.763-0.909) and an optimal cut-off value of 25.5 mmol/L (59.4% sensitivity and 95.5% specificity).AG level at admission may serve as a candidate marker for predicting the survival of patients with PQ poisoning.

Osteonecrosis of Femoral Head, An Overlooked Long-Term Complication after Paraquat Intoxication: A Retrospective Cohort Study

With increasing numbers of patients surviving acute intoxication phase, long-term complication after paraquat intoxication is a topic worth exploring, such as osteonecrosis (ON) of femoral head. We reviewed 86 paraquat-intoxicated survivors between 2000 and 2012 in Chang Gung Memorial Hospital, a 3700-bed tertiary hospital in Taiwan. With all the patients underwent same detoxification protocol in the acute stage, 17.4% of paraquat poisoning survivors developed ON of femoral head requiring surgery during follow up. Most of ON episodes occurred within 2 to 4 years after paraquat intoxication and then plateau after 6 years. ON patients exhibited higher SOFA scores than non-ON patients (2.80 ± 2.14 vs. 1.76 ± 1.52, p = 0.028). Furthermore, AKIN scores are also higher in the ON patients than non-ON patients (0.87 ± 1.13 vs. 0.38 ± 0.74, p = 0.040). Multivariate logistic regression showed higher AKIN score and higher partial pressure of carbon dioxide in the blood 48 hours after admission significantly predicted ON of femoral head after paraquat intoxication (p = 0.002 and p = 0.006 respectively). Larger studies with longer follow-up durations are warranted to confirm our finding.

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.

Acute kidney injury and the risk of mortality in patients with methanol intoxication

Background

Methanol poisoning is a serious public health issue in developing countries, but few data are available in the literature on acute kidney injury (AKI) after methanol intoxication.

Methods

This study examined the clinical features, spectrum and outcomes of AKI in patients with methanol intoxication and evaluated the predictors of mortality after methanol intoxication. A total of 50 patients with methanol intoxication were seen at Chang Gung Memorial Hospital between 2000 and 2013. Patients were grouped according to the status of renal damage as AKI (n = 33) or non-AKI (n = 19). Demographic, clinical, laboratory, and mortality data were obtained for analysis.

Results

Most patients were middle-aged (47.8 ± 14.9 years), predominantly male (74.0%), and habitual alcohol consumers (70.0%). Most incidents were oral exposures (96.0%) and unintentional (66.0%). Two (4.0%) patients attempted suicide by intravenous injection of methanol. Five (10.0%) patients suffered methanol intoxication after ingestion of methomyl pesticide that contained methanol as a solvent. Compared to non-AKI patients, the AKI patients were older (50.9 ± 13.7 versus 41.6 ± 15.6 years, P = 0.034), predominantly male (90.9% versus 42.8%, P = 0.000), more habitual alcohol users (84.8% versus 41.2%, P = 0.001) and had more unintentional exposures (82.8% versus 35.3%, P = 0.001). Furthermore, there was a higher incidence of respiratory failure (63.6% versus 29.4%, P = 0.022) in the AKI group than in the non-AKI group, respectively. The laboratory studies revealed that the AKI patients suffered from more severe metabolic acidosis than the non-AKI patients. By the end of this study, 13 (39.5%) AKI patients and 1 (5.9%) non-AKI patient had died. The overall in-hospital hospital mortality rate was 28%. In a multivariate binary logistic regression model, it was demonstrated that AKI (odds ratio 19.670, confidence interval 1.026–377.008, P = 0.048) and Glasgow coma scale score (odds ratio 1.370, confidence interval 1.079–1.739, P = 0.010) were significant factors associated with mortality. The Kaplan-Meier analysis disclosed that AKI patients suffered lower cumulative survival than non-AKI patients (log-rank test, chi-square = 5.115, P = 0.024).

Conclusions

AKI was common (66.0%) after methanol intoxication and was predictive of in-hospital hospital mortality. The development of AKI was associated with a 19.670-fold higher risk of in-hospital mortality.

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.

Rapid Simultaneous Determination of Paraquat and Creatinine in Human Serum Using a Piece of Paper

Paraquat intoxication is characterized by acute kidney injury and multi-organ failure, causing substantial mortality and morbidity. This study aims to develop a 2-in-1 paper-based analytical device to detect the concentrations of paraquat and creatinine in human serum, which can help clinicians diagnose patients with paraquat poisoning in a more rapid and geographically unrestricted manner. The procedure involves fabrication of a paper-based analytical device, i.e., printing of design on a filter paper, heating of wax-printed micro zone plates so as molten wax diffusing into and completely through the paper to the other side, forming hydrophobic boundaries that could act as detection zones for the paraquat colorimetric assay, and finally analysis using ImageJ software. The paper employed a colorimetric sodium dithionite assay to indicate the paraquat level in a buffer or human serum system in less than 10 min. In this study, colorimetric changes into blue color could be observed by the naked eye. By curve fitting models of sodium dithionite in normal human serum, we evaluated the serum paraquat levels for five paraquat patients. In the sodium dithionate assay, the measured serum paraquat concentrations in patients 1⁻5 were 22.59, 5.99, 26.52, 35.19 and 25.00 ppm, respectively. On the other hand, by curve fitting models of the creatinine assay in normal human serum, the measured serum creatinine concentrations were 16.10, 12.92, 13.82, 13.58 and 12.20 ppm, respectively. We found that the analytical performance of this device can compete with the standard of Clinical Laboratory of Chang Gung Memorial Hospital, with a less complicated sample preparation process and more rapid results. In conclusion, this 2-in-1 paper-based analytical device has the advantage of being simple and cheap, enabling rapid detection of paraquat intoxication as well as assessment of renal prognosis.

Exploring the potential benefit of natural product extracts in paraquat toxicity

Paraquat dichloride, a herbicide used for weed and grass control, is extremely toxic to humans and animals. The mechanisms of toxicity involve the redox cycling of paraquat resulting in the generation of reactive oxygen species and the depletion of the cellular NADPH. The major cause of death in paraquat poisoning is respiratory failure due to its specific uptake by and oxidative insult to the alveolar epithelial cells and inflammation with subsequent obliterating fibrosis. Paraquat also causes selective degeneration of dopaminergic neurons in the substantia nigra pars compacta, reproducing an important pathological feature of Parkinson disease. Currently, there are no antidotes for the treatment of paraquat poisoning and therapeutic management is mostly supportive and directed towards changing the disposition of the poison. The lack of effective treatments against paraquat poisoning has led to the exploration of novel compounds with antioxidant and/or anti-inflammatory properties. Recently, there is an interest in plant compounds, particularly those used in traditional medicine. Phytochemicals have been highlighted as a possible therapeutic modality for a variety of diseases due to their putative efficacies and safety. In this review, the status of plant extracts and traditional medicines in ameliorating the toxicity of paraquat is discussed.

A critical review of adverse effects to the kidney: mechanisms, data sources, and in silico tools to assist prediction

INTRODUCTION

The kidney is a major target for toxicity elicited by pharmaceuticals and environmental pollutants. Standard testing which often does not investigate underlying mechanisms has proven not to be an adequate hazard assessment approach. As such, there is an opportunity for the application of computational approaches that utilize multiscale data based on the Adverse Outcome Pathway (AOP) paradigm, coupled with an understanding of the chemistry underpinning the molecular initiating event (MIE) to provide a deep understanding of how structural fragments of molecules relate to specific mechanisms of nephrotoxicity. Aims covered: The aim of this investigation was to review the current scientific landscape related to computational methods, including mechanistic data, AOPs, publicly available knowledge bases and current in silico models, for the assessment of pharmaceuticals and other chemicals with regard to their potential to elicit nephrotoxicity. A list of over 250 nephrotoxicants enriched with, where possible, mechanistic and AOP-derived understanding was compiled. Expert opinion: Whilst little mechanistic evidence has been translated into AOPs, this review identified a number of data sources of in vitro, in vivo, and human data that may assist in the development of in silico models which in turn may shed light on the interrelationships between nephrotoxicity mechanisms.

Therapy with high-dose long-term antioxidant free radicals for severe paraquat poisoning: A pilot study

This study investigated the effects of high-dose long-term antioxidant free radicals on the mortality rate, creatinine (Cr) value, partial pressure of oxygen (PaO₂), alanine aminotransferase (ALT), as well as the incidence rates of lung fibrosis and dysfunction in the treatment of patients with severe paraquat (PQ) poisoning [toxic dose, 20 ml stock solution (20% w/v)]. A total of 23 cases of severe PQ poisoning treated in Xiangyang First People's Hospital, Hubei University of Medicine were collected (group 1), and they received conventional treatments such as immunosuppressive agents and/or hemoperfusion. Six patients were given high-dose long-term antioxidant therapy on the basis of conventional treatments (group 2). After treatment, 6 out of the 23 patients in group 1 survived, and all the 6 patients in group 2 survived, with the survival rate of 26.1 vs. 100% (p<0.01). The lowest PaO₂ value in group 1 was lower than that in group 2 (70.26±16.38 vs. 91.17±3.43 mmHg, p<0.01). The highest ALT value in group 1 was higher than that in group 2 (216.74±126.23 vs. 52.50±24.83 U/l, p<0.01). There was no significant difference in the incidence rate of lung fibrosis between the two groups of survived patients, but there were 6 patients that died of severe lung fibrosis in group 1. Besides, the incidence rate of lung dysfunction in patients in group 2 was significantly lower than that in survived patients in group 1 (p<0.01). High-dose long-term antioxidants are the most critical treatment option to improve the survival rate of high-dose PQ poisoning, they increase the patient's PaO₂, enhance liver function, reduce lung fibrosis and refine lung dysfunction.

Delayed death following paraquat poisoning: three case reports and a literature review

Paraquat (PQ) poisoning is principally reported in developing countries. However, most fatalities occur elsewhere due to the induction of multi-organ failure. PQ poisoning can hardly be managed by clinical practice, and no specific antidote has come into existence yet. Here three cases, including 17-, 20-, and 23-year-old men, who were poisoned with PQ, have been reported. Furthermore, the literature regarding biological mechanisms, clinical manifestation, and treatment of PQ-induced toxicity was reviewed. Patients who, either intentionally or accidentally, ingested PQ earlier were initially found to be stable at the emergency department (ED). Therefore, they were discharged from the hospital under a follow-up. However, after several days, the patients were referred to the hospital for the second time and despite cardiovascular resuscitation (CPR) efforts, they suddenly expired. The delayed death following exposure to PQ was reported for inducing gradual progressive pulmonary fibrosis, metabolic acidosis, neurotoxicity, renal failure, and liver injury in poisoned patients. Therefore, PQ-intoxicated patients should be supervised for up to several weeks, and kept in the hospital for a longer period of time. Clinical manifestations and laboratory findings are beneficial markers that act as useful predictors of PQ poisoning.

Mesenchymal stem cell therapy for paraquat poisoning: A systematic review and meta-analysis of preclinical studies

Background

Paraquat (PQ) poisoning can cause multiple organ failure, in which the lung is the primary target organ. There is currently no treatment for PQ poisoning. Mesenchymal stem cells (MSCs), which differentiate into multiple cell types, have generated much enthusiasm regarding their use for the treatment of several diseases. The aim of this study was to systematically review and analyze published preclinical studies describing MSC administration for the treatment of PQ poisoning in animal models to provide a basis for cell therapy.

Methods

The electronic databases PubMed and CBMdisc were searched in this systematic review and meta-analysis. The MSC treatment characteristics of animal models of PQ poisoning were summarized. After quality assessment was performed, the effects of MSC transplantation were evaluated based on the survival rate, lung wet/dry weight, fibrosis scores, oxidative stress response, and inflammatory response. Publication bias was assessed.

Results

Eleven controlled preclinical studies involving MSC transplantation in animal models of PQ poisoning were included in this review. MSC therapy improved the survival rate and reduced the lung wet/dry weight and histopathological fibrosis changes in most studies. MSCs decreased serum or plasma malondialdehyde levels in the acute phase after 7 and 14 d and increased serum or plasma superoxide dismutase and glutathione levels at the same time points. IL-1β, TNF-α and TGF-β1 levels in blood or lung tissues were decreased to different degrees by MSCs. Lung hydroxyproline was decreased by MSCs after 14 d. No obvious evidence of publication bias was found.

Conclusion

MSCs showed anti-fibrosis therapeutic effects in animal models of lung injury caused by PQ poisoning, which may be related to reduced oxidative stress and inflammatory cytokine levels. Our review indicates a potential therapeutic role for MSC therapy to treat PQ poisoning and serves to augment the rationale for clinical studies.

Rapamycin protects against paraquat-induced pulmonary epithelial-mesenchymal transition via the Wnt/β-catenin signaling pathway

Paraquat (PQ) is a herbicide that is widely used in developing countries, and pulmonary fibrosisis one of the most typical features of PQ poisoning. The molecular mechanism underlying PQ toxicity is largely unknown, which makes it difficult to treat. In the present study, western blot analysis, reverse transcription-quantitative polymerase chain reaction and fluorescent immunostaining were used to analyze the effects of rapamycin on PQ-induced epithelial-mesenchymal transition (EMT) in A549 and MRC-5 cells. It was revealed that rapamycin significantly downregulated the mesenchymal cell marker, α-smooth muscle actin, and significantly upregulated the epithelial cell marker, E-cadherin, at mRNA and protein expression levels compared with the PQ group. Treatment with PQ significantly increased Wnt1, low-density lipoprotein receptor-related protein (LRP)5, LRP6 and β-catenin expression levels in A549 cells, while rapamycin significantly inhibited these effects of PQ. Activation of the Wnt signaling pathway using lithium chloride attenuated the inhibitory effects of rapamycin on PQ-induced EMT. In conclusion, rapamycin protects against PQ-induced pulmonary EMT via the Wnt/β-catenin signaling pathway.

Point-of-care testing in the early diagnosis of acute pesticide intoxication: The example of paraquat

Acute pesticide intoxication is a common method of suicide globally. This article reviews current diagnostic methods and makes suggestions for future development. In the case of paraquat intoxication, it is characterized by multi-organ failure, causing substantial mortality and morbidity. Early diagnosis may save the life of a paraquat intoxication patient. Conventional paraquat intoxication diagnostic methods, such as symptom review and urine sodium dithionite assay, are time-consuming and impractical in resource-scarce areas where most intoxication cases occur. Several experimental and clinical studies have shown the potential of portable Surface Enhanced Raman Scattering (SERS), paper-based devices, and machine learning for paraquat intoxication diagnosis. Portable SERS and new SERS substrates maintain the sensitivity of SERS while being less costly and more convenient than conventional SERS. Paper-based devices provide the advantages of price and portability. Machine learning algorithms can be implemented as a mobile phone application and facilitate diagnosis in resource-limited areas. Although these methods have not yet met all features of an ideal diagnostic method, the combination and development of these methods offer much promise.