Toxicity and toxicokinetics of Amanita exitialis in beagle dogs

Toxicokinetics of α- and β-amanitin in mice following single and combined administrations: Simulating in vivo amatoxins processes in clinical cases

α-Amanitin and β-amanitin, two of the most toxic amatoxin compounds, typically coexist in the majority of Amanita mushrooms. The aim of this study was to use a newly developed ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method to determine the toxicokinetics and tissue distribution of α- and β-amanitin following single or combined oral (po) administration in mice. α-Amanitin and β-amanitin administered at 2 or 10 mg/kg doses showed similar toxicokinetic profiles, except for peak concentration (Cmax). The elimination half-life (t1/2) values of α-amanitin and β-amanitin in mice were 2.4-2.8 h and 2.5-2.7 h, respectively. Both α- and β-amanitin were rapidly absorbed into the body, with times to reach peak concentration (Tmax) between 1.0 and 1.5 h. Following single oral administration at 10 mg/kg, the Cmax was significantly lower for α-amanitin (91.1 μg/L) than for β-amanitin (143.1 μg/L) (p < 0.05). The toxicokinetic parameters of α-amanitin, such as t1/2, mean residence time (MRT), and volume of distribution (Vz/F) and of β-amanitin, such as Vz/F, were significantly different (p < 0.05) when combined administration was compared to single administration. Tissues collected at 24 h after po administration revealed decreasing tissue distributions for α- and β-amanitin of intestine > stomach > kidney > lung > spleen > liver > heart. The substantial distribution of toxins in the kidney corresponds to the known target organs of amatoxin poisoning. The content in the stomach, liver, and kidney was significantly higher for of β-amanitin than for α-amanitin at 24 h following oral administration of a 10 mg/kg dose. No significant difference was detected in the tissue distribution of either amatoxin following single or combined administration. After po administration, both amatoxins were primarily excreted through the feces. Our data suggest the possibility of differences in the toxicokinetics in patients poisoned by mushrooms containing both α- and β-amanitin than containing a single amatoxin. Continuous monitoring of toxin concentrations in patients' blood and urine samples is necessary in clinical practice.

α-amanitin induce inflammatory response by activating ROS/NF-κB-NLRP3 signaling pathway in human hepatoma HepG2 cells

α-amanitin (AMA) is a hepatotoxic mushroom toxin responsible for over 90% of mushroom poisoning fatalities worldwide, seriously endangering human life and health. Few evidences have indicated that AMA leads to inflammatory responses and inflammatory infiltration in vitro and in vivo. However, the molecular mechanism remains unknown. In this study, human hepatocellular carcinomas cells (HepG2) were exposed to AMA at various concentrations for short period of times. Results revealed that AMA increased ROS production and elevated the releases of malondialdehyde (MDA) and lactate dehydrogenase (LDH), resulting in oxidative damage in HepG2 cells. Also, AMA exposure significantly increased the secreted levels of inflammatory cytokines and activated the NLRP3 inflammasome. The inflammatory responses were reversed by NLRP3 inhibitor MCC950 and NF-κB inhibitor Bay11-7082. Additionally, N-acetylcysteine (NAC) blocked the upregulation of the NF-κB/NLRP3 signaling pathway and remarkably alleviated the inflammatory response. These results demonstrated that AMA could induce inflammation through activating the NLRP3 inflammasome triggered by ROS/NF-κB signaling pathway. Our research provides new insights into the molecular mechanism of AMA-induced inflammation damage and may contribute to establish new prevention strategies for AMA hepatotoxicity.

Colorimetric assay for α-amanitin based on inhibition of carbon dots/AuNPs nanoenzyme activity

Accidental ingestion of poisonous mushrooms leading to poisoning is a global issue. The most important and lethal toxin causing mushroom poisoning is α-amanitin, with a lethal dose of about 0.1 mg kg-1. Rapid detection of wild mushrooms before consumption or rapid identification of toxins after poisoning can effectively reduce the occurrence of fatalities. This study established a method for detecting α-amanitin using carbon dots/AuNPs nanoenzymes (D-Glu-CDs/AuNPs) with robust peroxidase-like activity. This nanoenzyme was prepared employing glucose carbon dots and sodium citrate as reducing and stabilizing agents, respectively. It could oxidize the substrate TMB (tetramethylbenzidine) to produce blue o-TMB. When α-amanitin specifically bound to the active site of the nanoenzyme, a resultant decrease was observed in catalytic activity and the absorbance value at 652 nm. The regression equation Y = -0.06083x + 0.9643, with an R2 value of 0.996, was obtained. The limit of detection was determined to be 48.03 ng mL-1, and the recoveries in urine ranged from 91.2% to 97.6%. This method enabled the visualization of α-amanitin, and the whole detection process was completed within 20 min. The approach holds promise for the quantitative and qualitative determination of α-amanitin in urine samples.

Effects of interrupting the enterohepatic circulation in amatoxin intoxications

BACKGROUND

Interruption of the enterohepatic circulation is regarded as an effective way to treat patients with amatoxin poisoning. Nonetheless, its effectiveness has not yet been systematically evaluated. Therefore, we performed a systematic review to investigate the role of enterohepatic circulation on patient outcome and clinical laboratory values. We specifically sought to evaluate the effect of activated charcoal, which absorbs drugs and toxins in the gastrointestinal tract.

METHODS

A previously established database with data extracted from case reports and series from literature, supplemented with recent publications, was used. Patient characteristics, outcome, and laboratory values were evaluated.

RESULTS

We included 133 publications describing a total of 1,119 unique cases. Survival was 75 per cent in the control group (n = 452), whereas in the group treated with single or multiple doses of activated charcoal (n = 667) survival was 83 per cent (P < 0.001, odds ratio 1.89 [95 per cent confidence interval 1.40-2.56]). Furthermore, no difference in peak values of alanine aminotransferase and aspartate aminotransferase activities were observed, whereas peak values of total serum bilirubin concentration and international normalized ratio were statistically significantly reduced in patients treated with activated charcoal.

DISCUSSION

The ability of activated charcoal to enhance the elimination of amatoxin through interruption of the enterohepatic circulation offers a potentially safe and inexpensive therapy for patients in the post-absorptive phase.

LIMITATIONS

Limitations include the potential for publication bias, the lack of universal confirmation of amatoxin concentrations, and the inability to directly measure enterohepatic circulation of amatoxin.

CONCLUSION

Treatment with activated charcoal in patients with amatoxin poisoning was associated with a greater chance of a successful outcome. Additionally, activated charcoal was associated with a reduction in markers of liver function, but not markers of liver injury.

Unraveling Hematotoxicity of α-Amanitin in Cultured Hematopoietic Cells

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

A network system for the prevention and treatment of mushroom poisoning in Chuxiong Autonomous Prefecture, Yunnan Province, China: implementation and assessment

BACKGROUND

Mushroom poisoning is a major public health issue in China. The integration of medical resources from different institutes of different levels is crucial in reducing the harm of mushroom poisoning. However, few studies have provided comprehensive implementation procedures and postimplementation effectiveness evaluations. To reduce the harm caused by mushroom poisoning, a network system for the prevention and treatment of mushroom poisoning (NSPTMP) was established in Chuxiong, Yunnan Province, a high-risk area for mushroom poisoning.

METHODS

The NSPTMP consists of three types of institutions, namely, centers for disease prevention, hospitals, and health administration departments, with each kind of institution comprising prefecture, county/city, town, and village levels. After three years of implementation, the network was evaluated by comparing the indices before and after network implementation using data from the "Foodborne Disease Outbreak Surveillance System" and 17 hospitals in Chuxiong. The indices included the fatalities caused by mushroom poisoning, the composition ratios of different types of mushrooms for both outpatients and inpatients and the hospitalization rates.

RESULTS

Compared to the average fatality rate of mushroom poisoning from 2015 to 2017, the average fatality rate from 2018 to 2020 significantly decreased from 0.57 to 0.06% (P < 0.001). Regarding the poisonous genus containing lethal mushrooms, the outpatient and inpatient composition ratios significantly decreased for Amanita (9.36-2.91% and 57.23-17.68%, respectively) and Russula (15.27-8.41%) (P < 0.05). Regarding poisonous mushrooms that caused mild symptoms, the outpatient and inpatient composition ratios significantly increased for Scleroderma (5.13-13.90% and 2.89-18.90%, respectively) and Boletaceae (19.08-31.71%) (P < 0.05), and the hospitalization rates significantly increased for Scleroderma (6.33-18.02%) and Boletaceae (5.65-12.71%) (P < 0.05).

CONCLUSIONS

These findings suggest that the NSPTMP effectively reduced the harm caused by mushroom poisoning. In addition to the integration of medical resources, the development of poisonous mushroom identification, hierarchical treatment systems in hospitals, public education, and professional training also played important roles in improving the system's effectiveness. The establishment and evaluation of the NSPTMP in Chuxiong Prefecture can provide valuable insights and serve as a model for other regions facing similar challenges in managing mushroom poisoning.

Hypoadrenocorticism in a Dog Following Recovery from Alpha-Amanitin Intoxication

A 10-year-old, female spayed Labrador Retriever was referred for acute hepatopathy and urinary retention. Blood work from the initial presentation (day 0) revealed a severe, mixed hepatopathy. Over the course of the patient's hospitalization, the patient developed liver insufficiency. Urine was submitted for toxicological screening and revealed detection of a trace concentration of alpha-amanitin. The patient was treated supportively for alpha-amanitin intoxication and was discharged from the hospital on day 8, with most biochemical parameters being markedly improved. The patient was persistently hyporexic at the time of discharge. On day 15, at a recheck appointment, the patient had lost 2.4 kg and liver enzymology revealed improved values. On day 24, the patient was presented for anorexia and vomiting and had lost another 2.3 kg. Blood work and endocrinological testing at that time were consistent with hypoadrenocorticism. The patient was started on glucocorticoids and mineralocorticoids. At day 106, the patient was doing well clinically while receiving monthly mineralocorticoids and daily glucocorticoids. This case report is the first to describe the chronological association between alpha-amanitin-induced liver dysfunction and the subsequent development of adrenal insufficiency in a dog.

Analytical methods for amatoxins: A comprehensive review

Amatoxins are toxic bicyclic octapeptides found in certain wild mushroom species, particularly Amanita phalloides. These mushrooms contain predominantly α- and β-amanitin, which can lead to severe health risks for humans and animals if ingested. Rapid and accurate identification of these toxins in mushroom and biological samples is crucial for diagnosing and treating mushroom poisoning. Analytical methods for the determination of amatoxins are critical to ensure food safety and prompt medical treatment. This review provides a comprehensive overview of the research literature on the determination of amatoxins in clinical specimens, biological and mushroom samples. We discuss the physicochemical properties of toxins, highlighting their influence on the choice of the analytical method and the importance of sample preparation, particularly solid-phase extraction with cartridges. Chromatographic methods are emphasised with a focus on liquid chromatography coupled to mass spectrometry as one of the most relevant analytical method for the determination of amatoxins in complex matrices. Furthermore, current trends and future perspectives in amatoxin detection are also suggested.

Determination of protein-bound α-amanitin in mouse plasma: A potential new indicator of poisoning with the mushroom toxin α-amanitin

Approximately 70%∼90% of mushroom poisoning deaths are caused by the class of mushroom toxins known as amatoxins. However, the rapid elimination of amatoxins from plasma within 48 h after mushroom ingestion limits the practical value of plasma amatoxin analysis as a diagnostic indicator of Amanita mushroom poisoning. To increase the positive detection rate and extend the detection window of amatoxin poisoning, we developed a new method to detect protein-bound α-amanitin based on the hypothesis that RNAP II-bound α-amanitin released from the tissue into the plasma could be degraded by trypsin hydrolysis and then detected by conventional liquid chromatography-mass spectrometry (LC‒MS). Toxicokinetic studies on mice intraperitoneally injected with 0.33 mg/kg α-amanitin were conducted to obtain and compare the concentration trends, detection rates, and detection windows of both free α-amanitin and protein-bound α-amanitin. By comparing detection results with and without trypsin hydrolysis in the liver and plasma of α-amanitin-poisoned mice, we verified the credibility of this method and the existence of protein-bound α-amanitin in plasma. Under the optimized trypsin hydrolysis conditions, we obtained a time-dependent trend of protein-bound α-amanitin in mouse plasma at 1-12 days postexposure. In contrast to the short detection window (0-4 h) of free α-amanitin in mouse plasma, the detection window of protein-bound α-amanitin was extended to 10 days postexposure, with a total detection rate of 53.33%, ranging from the limit of detection to 23.94 μg/L. In conclusion, protein-bound α-amanitin had a higher positive detection rate and a longer detection window than free α-amanitin in mice.

The characteristics of liver injury induced by Amanita and clinical value of α-amanitin detection

BACKGROUND

Amanita poisoning as a foodborne disease has raised concerning mortality issues. Reducing the interval between mushroom ingestion and medical intervention could greatly influence the outcomes of Amanita poisoning patients, while treatment is highly dependent on a confirmed diagnosis. To this end, we developed an early detection-guided intervention strategy by optimizing diagnostic process with performing α-amanitin detection, and further explored whether this strategy influenced the progression of Amanita poisoning.

METHODS

This study was a retrospective analysis of 25 Amanita poisoning patients. Thirteen patients in the detection group were diagnosed mainly based on α-amanitin detection, and 12 patients were diagnosed essentially on the basis of mushroom consumption history, typical clinical patterns and mushroom identification (conventional group). Amanita poisoning patients received uniform therapy, in which plasmapheresis was executed once confirming the diagnosis of Amanita poisoning. We compared the demographic baseline, clinical and laboratory data, treatment and outcomes between the two groups, and further explored the predictive value of α-amanitin concentration in serum.

RESULTS

Liver injury induced by Amanita appeared worst at the fourth day and alanine aminotransferase (ALT) rose higher than aspartate aminotransferase (AST). The mortality rate was 7.7% (1/13) in the detection group and 50.0% (6/12) in the conventional group (P = 0.030), since patients in the detection group arrived hospital much earlier and received plasmapheresis at the early stage of disease. The early detection-guided intervention helped alleviate liver impairment caused by Amanita and decreased the peak AST as well as ALT. However, the predictive value of α-amanitin concentration in serum was still considered limited.

CONCLUSIONS

In the management of mushroom poisoning, consideration should be given to the rapid detection of α-amanitin in suspected Amanita poisoning patients and the immediate initiation of medical treatment upon a positive toxin screening result.

[Highly sensitive determination of three kinds of amanitins in urine and plasma by ultra performance liquid chromatography-triple quadrupole mass spectrometry coupled with immunoaffinity column clean-up]

Cases of toxic mushroom poisoning occur frequently in China every year. In particular, mushrooms containing amanitins can cause acute liver damage, with high mortality rates. The symptoms of acute liver damage are experienced 9-72 h after consumption of the mushrooms. At this time, the concentration of amanitins in blood and urine is too low to be detected even by the highly sensitive ultra performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS), thus rendering clinical diagnosis and treatment difficult. To this end, a method was developed for the determination of α-amanitin, β-amanitin and γ-amanitin in urine and plasma by UPLC-MS/MS. Urine and plasma samples were extracted and cleaned up by using an immunoaffinity column. A sample of 2.00 mL urine or 1.00 mL of plasma was diluted with 8.00 mL of phosphate buffer solution (PBS) and then loaded onto the immunoaffinity column at a flow rate of 0.5-1.0 mL/min. After washing the column with 10 mL of PBS and 13 mL of water successively, the bound amanitins were eluted with 3.00 mL of methanol-acetone (1∶1, v/v). The eluent was dried under nitrogen at 55 ℃. The residue was dissolved in 100 μL of 10% (v/v) methanol aqueous solution. The amanitins in urine were concentrated 20 times, while those in plasma were concentrated 10 times. Chromatographic separation was performed on a Kinetex Biphenyl column (100 mm × 2.1 mm, 1.7 μm) with gradient elution using methanol and 0.005% (v/v) formic acid aqueous solution as mobile phases. The three amanitins were detected by negative electrospray ionization tandem mass spectrometry in the multiple reaction monitoring (MRM) mode and quantified by the solvent standard curve external standard method. Method validation was performed as recommended by the European Drug Administration (EMEA). Four levels of quality control (QC) samples were prepared, which covered the calibration curve range, viz., the limit of quantification (LOQ), within three times the LOQ (low QC), medium QC, and at 85% of the upper calibration curve range (high QC), and used to test the accuracy, precision, matrix effect, extraction recovery, and stability. The calibration curves for the three amanitins showed good linear relationships in the range of 0.1-200 ng/mL, and the correlation coefficients (r) were greater than 0.999. The matrix effects and extraction efficiencies of the three amanitins in urine and plasma were 92%-108% and 90%-103%, respectively, and the coefficients of variation were less than 13%. The accuracies of the three amanitins in urine were within -9.4%-8.0%. The repeatability and intermediate accuracies were 3.0%-14% and 3.5%-18%, respectively. When the sampling volume was 2.00 mL, the limits of detection of the three amanitins in urine were 0.002 ng/mL. The accuracies of the three amanitins in plasma were within -13%-8.0%. The repeatability and intermediate accuracies were 3.9%-9.7% and 5.5%-12%, respectively. When the sampling volume was 1.00 mL, the limits of detection of the three amanitins in plasma were 0.004 ng/mL. The developed method is simple, sensitive, and accurate. During toxic mushroom poisoning detection, 0.0067 ng/mL of α-amanitin and 0.0059 ng/mL of β-amanitin were detected in the urine of poisoned patients 138 h after ingesting poisonous mushrooms. This method has successfully solved the problem of detecting ultra-trace levels of amanitins in the urine and plasma of poisoned patients. It has important practical significance for the early diagnosis, early treatment, and mortality reduction of suspected poisoning patients. This method can also provide reliable technical support for future research on the toxicological effects and in vivo metabolism of these toxins.

Toxicokinetics of β-Amanitin in Mice and In Vitro Drug-Drug Interaction Potential

The toxicokinetics of β-amanitin, a toxic bicyclic octapeptide present abundantly in Amanitaceae mushrooms, was evaluated in mice after intravenous (iv) and oral administration. The area under plasma concentration curves (AUC) following iv injection increased in proportion to doses of 0.2, 0.4, and 0.8 mg/kg. β-amanitin disappeared rapidly from plasma with a half-life of 18.3−33.6 min, and 52.3% of the iv dose was recovered as a parent form. After oral administration, the AUC again increased in proportion with doses of 2, 5, and 10 mg/kg. Absolute bioavailability was 7.3−9.4%, which resulted in 72.4% of fecal recovery from orally administered β-amanitin. Tissue-to-plasma AUC ratios of orally administered β-amanitin were the highest in the intestine and stomach. It also readily distributed to kidney > spleen > lung > liver ≈ heart. Distribution to intestines, kidneys, and the liver is in agreement with previously reported target organs after acute amatoxin poisoning. In addition, β-amanitin weakly or negligibly inhibited major cytochrome P450 and 5′-diphospho-glucuronosyltransferase activities in human liver microsomes and suppressed drug transport functions in mammalian cells that overexpress transporters, suggesting the remote drug interaction potentials caused by β-amanitin exposure.

Utilizing the DNA Aptamer to Determine Lethal α-Amanitin in Mushroom Samples and Urine by Magnetic Bead-ELISA (MELISA)

Amanita poisoning is one of the most deadly types of mushroom poisoning. α-Amanitin is the main lethal toxin in amanita, and the human-lethal dose is about 0.1 mg/kg. Most of the commonly used detection techniques for α-amanitin require expensive instruments. In this study, the α-amanitin aptamer was selected as the research object, and the stem-loop structure of the original aptamer was not damaged by truncating the redundant bases, in order to improve the affinity and specificity of the aptamer. The specificity and affinity of the truncated aptamers were determined using isothermal titration calorimetry (ITC) and gold nanoparticles (AuNPs), and the affinity and specificity of the aptamers decreased after truncation. Therefore, the original aptamer was selected to establish a simple and specific magnetic bead-based enzyme linked immunoassay (MELISA) method for α-amanitin. The detection limit was 0.369 μg/mL, while, in mushroom it was 0.372 μg/mL and in urine 0.337 μg/mL. Recovery studies were performed by spiking urine and mushroom samples with α-amanitin, and these confirmed the desirable accuracy and practical applicability of our method. The α-amanitin and aptamer recognition sites and binding pockets were investigated in an in vitro molecular docking environment, and the main binding bases of both were T3, G4, C5, T6, T7, C67, and A68. This study truncated the α-amanitin aptamer and proposes a method of detecting α-amanitin.

[Acute liver failure in a dog after mushroom intake, presumably of the genus Amanita]

A 4-year-old, neutered male Husky-mix dog weighing 29.4 kg that reportedly ingested a mushroom most likely of the genus Amanita one day prior to presentation exhibited signs of diarrhea, vomitus, inappetence and progressively worsening lethargy. Clinical chemistry revealed hypoglycemia, hyperbilirubinemia, decreased prothrombin and thromboplastin time, as well as increased liver enzyme activities. Despite hospitalization and supportive therapy over a period of 3 days the dog's general condition worsened leading to euthanasia. The pathomorphological findings were characterized by hemorrhage in several organs, hemorrhagic ingesta, icterus, and marked hepatic cellular necrosis.

Pharmacokinetics of α-amanitin in mice using liquid chromatography-high resolution mass spectrometry and in vitro drug-drug interaction potentials

The aim of this study was to determine pharmacokinetics of α-amanitin, a toxic bicyclic octapeptide isolated from the poisonous mushrooms, following intravenous (iv) or oral (po) administration in mice using a newly developed and validated liquid chromatography-high resolution mass spectrometry. The iv injected α-amanitin disappeared rapidly from the plasma with high a clearance rate (26.9-30.4 ml/min/kg) at 0.1, 0.2, or 0.4 mg/kg doses, which was consistent with a rapid and a major excretion of α-amanitin via the renal route (32.6%). After the po administration of α-amanitin at doses of 2, 5, or 10 mg/kg to mice, the absolute bioavailability of α-amanitin was 3.5-4.8%. Due to this low bioavailability, 72.5% of the po administered α-amanitin was recovered from the feces. When α-amanitin is administered po, the tissue to plasma area under the curve ratio was higher in stomach > large intestine > small intestine > lung ~ kidneys > liver but not detected in brain, heart, and spleen. The high distribution of α-amanitin to intestine, kidneys, and liver is in agreement with the previously reported major intoxicated organs following acute α-amanitin exposure. In addition, α-amanitin weakly or negligibly inhibited cytochrome P450 and 5'-diphospho-glucuronosyltransferase enzymes activity in human liver microsomes as well as major drug transport functions in mammalian cells overexpressing transporters. Data suggested remote drug interaction potential may be associated with α-amanitin exposure.

Physical examination, serum biochemical, and coagulation abnormalities, treatments, and outcomes for dogs with toxicosis from α-amanitin-containing mushrooms: 59 cases (2006-2019)

OBJECTIVE

To report history, physical examination findings, clinicopathologic abnormalities, treatments, and outcomes of dogs with confirmed α-amanitin toxicosis resulting from ingestion of α-amanitin-containing mushrooms, and to report whether any differences were significant between survivors and nonsurvivors.

ANIMALS

59 dogs.

PROCEDURES

Medical records of all dogs with confirmed α-amanitin toxicosis presented to a northern California emergency and specialty veterinary hospital between January 2006 and July 2019 were reviewed for signalment; body weight; history; physical examination findings including rectal temperature at presentation; results of serum biochemical analyses, coagulation tests, and a test for the detection of α-amanitin in urine; treatments; and outcomes. Differences for each were compared between survivors and nonsurvivors.

RESULTS

Among the 59 dogs, 36 were < 1 year of age; 56 had variable clinical signs that included vomiting, diarrhea, anorexia, and weakness or lethargy; and 22 had rectal temperatures > 39.2°C (102.5°F) at presentation. Cases were seen throughout the calendar year. At presentation, alanine aminotransferase activity was mildly to markedly increased in 97% of dogs, hypoglycemia was noted in 78%, and coagulation times were prolonged in 91%. Most dogs that rapidly decompensated died; however, 13 dogs survived to hospital discharge and completely recovered.

CONCLUSIONS AND CLINICAL RELEVANCE

Ability to recognize dogs with α-amanitin toxicosis on the basis of clinical signs, physical examination findings, and clinicopathologic test results is essential because mushroom ingestion is rarely observed and immediate treatment is necessary. Dogs that have marked hypoglycemia or coagulopathy may have a poor prognosis.

Transcriptional inhibition of feline immunodeficiency virus by alpha-amanitin

Alpha-amanitin, one of the amatoxins in egg amanita, has a cyclic peptide structure, and was reported as having antiviral activity against several viruses. We investigated whether α-amanitin has antiviral activity against feline immunodeficiency virus (FIV). FL-4 cells persistently infected with FIV Petaluma were cultured with α-amanitin. Reverse transcriptase (RT) activity in the supernatant of FL-4 cells was significantly inhibited by α-amanitin. In addition, the production of FIV core protein in FL-4 cells was inhibited by α-amanitin when analyzed by western blotting. Furthermore, α-amanitin inhibited the transcription of FIV in real-time RT-PCR. These data suggested that α-amanitin showed anti-FIV activity by inhibiting the RNA transcription level.

Rapid, Sensitive, and Accurate Point-of-Care Detection of Lethal Amatoxins in Urine

Globally, mushroom poisonings cause about 100 human deaths each year, with thousands of people requiring medical assistance. Dogs are also susceptible to mushroom poisonings and require medical assistance. Cyclopeptides, and more specifically amanitins (or amatoxins, here), are the mushroom poison that causes the majority of these deaths. Current methods (predominantly chromatographic, as well as antibody-based) of detecting amatoxins are time-consuming and require expensive equipment. In this work, we demonstrate the utility of the lateral flow immunoassay (LFIA) for the rapid detection of amatoxins in urine samples. The LFIA detects as little as 10 ng/mL of α-amanitin (α-AMA) or γ-AMA, and 100 ng/mL of β-AMA in urine matrices. To demonstrate application of this LFIA for urine analysis, this study examined fortified human urine samples and urine collected from exposed dogs. Urine is sampled directly without the need for any pretreatment, detection from urine is completed in 10 min, and the results are read by eye, without the need for specialized equipment. Analysis of both fortified human urine samples and urine samples collected from intoxicated dogs using the LFIA correlated well with liquid chromatography-mass spectrometry (LC-MS) methods.

Glycosylation profiling of dog serum reveals differences compared to human serum

Glycosylation is the most common post-translational modification of serum proteins, and changes in the type and abundance of glycans in human serum have been correlated with a growing number of human diseases. While the glycosylation pattern of human serum is well studied, little is known about the profiles of other mammalian species. Here, we report detailed glycosylation profiling of canine serum by hydrophilic interaction chromatography-ultraperformance liquid chromatography (HILIC-UPLC) and mass spectrometry. The domestic dog (Canis familiaris) is a widely used model organism and of considerable interest for a large veterinary community. We found significant differences in the serum N-glycosylation profile of dogs compared to that of humans, such as a lower abundance of galactosylated and sialylated glycans. We also compare the N-glycan profile of canine serum to that of canine IgG – the most abundant serum glycoprotein. Our data will serve as a baseline reference for future studies when performing serum analyses of various health and disease states in dogs.

Mushroom Poisoning Cases in Dogs and Cats: Diagnosis and Treatment of Hepatotoxic, Neurotoxic, Gastroenterotoxic, Nephrotoxic, and Muscarinic Mushrooms

Ingestion of poisonous mushrooms by small animals can lead to liver failure, neurotoxicity, or gastrointestinal irritation. Although amanita poisoning can be lethal, ingestion of other toxic mushrooms is generally self-limiting and not life threatening. Most cases are undiagnosed, as routine diagnostic tests only exist for amanitins and psilocin. Early detection of amanitin exposure can greatly aid in the therapeutic intervention by allowing veterinarians to make timely decisions regarding patient management. Treatment is generally supportive, but specific therapeutic measures exist for amanitin and psilocin exposures.

Effect of Biliary Drainage on the Toxicity and Toxicokinetics of Amanita exitialis in Beagles

Amatoxin poisoning induces delayed-onset acute liver failure, which are responsible for more than 90% of deaths in mushroom poisoning. It has been postulated from animal and human studies that biliary drainage interrupting enterohepatic amatoxin circulation may affect amatoxin poisoning. Dogs were randomly divided into four groups of six animals each. In 20 mg/kg and 60 mg/kg with biliary drainage groups, after accepting bile drainage operation, beagles were fed Amanita exitialis powder (20 or 60 mg/kg) in starch capsules. In control and bile drainage groups, the beagle dogs were fed with empty capsules. They were assessed for toxicity signs, biochemical and pathological changes, and peptide toxins in plasma, urine and bile. The data were directly compared with those from our published studies on Amanita exitialis-exposed beagles without biliary drainage. Amatoxins were rapidly absorbed and eliminated from plasma after Amanita exitialis ingestion. Amatoxins in 0–1-day urine accounted for more than 90% of the total urine excretion, and amatoxins in bile accounted for less than 20% of the total urine and bile excretion. The dogs with biliary drainage showed less severe toxicity signs and biochemical and pathological changes and much lower internal exposure than dogs without biliary drainage. Biliary drainage caused a more than 70% reduction in intestinal amatoxin absorption and could reduce amatoxin absorption from the gastrointestinal tract.