Treatment of intoxication with Cortinarius speciosissimus using an antioxidant therapy

The most dreadful mushroom toxins: a review of their toxicological mechanisms, chemical structural characteristics, and treatment

Mushroom consumption is a worldwide custom that continues to grow in popularity. On the other hand, foraging for wild mushrooms can lead to serious disease and even death if deadly mushrooms are accidentally consumed. Mushroom poisoning is difficult to diagnose and treat since the symptoms are similar to those of other disorders. In terms of chemistry, mushroom poisoning is associated with extraordinarily strong toxins, meaning that isolating and identifying toxins has substantial scientific relevance, especially in understanding the lethal components of toxic mushrooms. Most of these toxins exhibit exceptional physiological features that might help enhance chemistry, biochemistry, physiology, and pharmacology research. Despite the discovery of more than 100 poisons, several dangerous mushrooms remain unexplored. This review covers the chemistry (including chemical structures, complete synthesis, and biosynthesis), as well as the toxicology, namely the toxicokinetics, mechanisms of toxicology, and clinical toxicology of these poisons, in addition to the discussion of the development of their most effective diagnostic and therapeutic strategies with the hopes of spurring additional studies, focusing on individual classes of toxins found in poisonous mushrooms such as amatoxins, gyromitrin, orellanine, and phallatoxins. See also the graphical abstract(Fig. 1).

Orellanine: From Fungal Origin to a Potential Future Cancer Treatment

Fungal metabolites represent an underutilized resource in the development of novel anticancer drugs. This review will focus on the promising fungal nephrotoxin orellanine, found in mushrooms including Cortinarius orellanus (Fools webcap). Emphasis will be placed on its historical significance, structural features, and associated toxicomechanics. Chromatographic methods for analysis of the compound and its metabolites, its synthesis, and chemotherapeutic potential are also discussed. Although orellanine's exceptional selectivity for proximal tubular cells is well documented, the mechanics of its toxicity in kidney tissue remains disputed. Here, the most commonly proposed hypotheses are detailed in the context of the molecule's structure, the symptoms seen following ingestion, and its characteristic prolonged latency period. Chromatographic analysis of orellanine and its related substances remains challenging, while biological evaluation of the compound is complicated by uncertainty regarding the role of active metabolites. This has limited efforts to structurally refine the molecule; despite numerous established methods for its synthesis, there is minimal published material on how orellanine's structure might be optimized for therapeutic use. Despite these obstacles, orellanine has generated promising data in preclinical studies of metastatic clear cell renal cell carcinoma, leading to the early 2022 announcement of phase I/II trials in humans.

Human Poisoning from Poisonous Higher Fungi: Focus on Analytical Toxicology and Case Reports in Forensic Toxicology

Several families of higher fungi contain mycotoxins that cause serious or even fatal poisoning when consumed by humans. The aim of this review is to inventory, from an analytical point of view, poisoning cases linked with certain significantly toxic mycotoxins: orellanine, α- and β-amanitin, muscarine, ibotenic acid and muscimol, and gyromitrin. Clinicians are calling for the cases to be documented by toxicological analysis. This document is therefore a review of poisoning cases involving these mycotoxins reported in the literature and carries out an inventory of the analytical techniques available for their identification and quantification. It seems indeed that these poisonings are only rarely documented by toxicological analysis, due mainly to a lack of analytical methods in biological matrices. There are many reasons for this issue: the numerous varieties of mushroom involved, mycotoxins with different chemical structures, a lack of knowledge about distribution and metabolism. To sum up, we are faced with (i) obstacles to the documentation and interpretation of fatal (or non-fatal) poisoning cases and (ii) a real need for analytical methods of identifying and quantifying these mycotoxins (and their metabolites) in biological matrices.

Long-term clinical outcome for patients poisoned by the fungal nephrotoxin orellanine

Background

Accidental intake of mushrooms of the Cortinarius species (deadly webcap) may cause irreversible renal damage and the need for dialysis or transplantation. The species is found in forests of Northern Europe, Scandinavia and North America and may be mistaken for other edible mushrooms. The highly selective nephrotoxic compound of the mushroom is called orellanine. Very little is known about the long-term effects of the nephrotoxin.

Methods

We identified patients who ingested deadly webcap in the period of 1979 to 2012. Informed consent and medical records were obtained for 28 of the 39 cases that occurred during the 34-year period. A case control group was also studied based on sex, age and initiation of dialysis or transplantation.

Results

The average age at time of the accidental intake was 40 ± 3 (n = 28) years. 64% of patients were male, and 22 of 28 patients developed acute kidney injury requiring dialysis. Serum creatinine peaked at 1 329 ± 133 μmol/l, and serum urea was 31 ± 3.5 mmol/l. No signs of acute damage were present in any other organ. The average time of follow-up was 16.9 ± 2.1 years (1.24–34.3 years, n = 28). 15 patients were transplanted and 3 also had a second graft. At follow-up, 23 patients were alive, and five had died at ages of 67 ± 5 (range 54–84). The outcome was similar in the case control group with 6 deaths in 20 patients.

Conclusion

We conclude that the long-term prognosis for patients poisoned by deadly webcap who lost their renal function is not different compared to other patients in active uremic care.

Human and experimental toxicology of orellanine

Orellanine is a nephrotoxic toxin produced by some mushroom species of the Cortinarius genus, typically found in Europe and North America. The nephrotoxicity of Cortinarius orellanus is well known and was first recognized in the 1950s when this mushroom was identified as the cause of a mass poisoning in Poland. Typically, onset of symptoms is delayed for 1-2 weeks after ingestion. Some patients suffer mild gastrointestinal discomfort in the latency period before developing signs of renal impairment due to severe interstitial nephritis, acute focal tubular damage, and interstitial fibrosis. There is no specific antidote to orellanine poisoning. The mainstay of treatment is the prevention of secondary complications of kidney failure, adequate dialysis and, in the case of incomplete recovery, management of chronic renal insufficiency. : In this work, we aim to review about Cortinarius species, including epidemiological studies, chemical structure, toxicokinetics, toxic doses, mechanisms of toxicity, diagnosis, prognosis, and treatment options.

Renal involvement in mushroom poisoning: The case of Orellanus syndrome

Although mushroom poisoning is a rare cause of acute renal injury, in some cases it may lead to the development of a severe and irreversible renal failure. Orellanus syndrome is the most important example of organic renal damage related to mushroom consumption. It is caused by the ingestion of orellanine, the main toxin of different types of Cortinarius mushrooms (Cortinarius speciosissimus, C. orellanus, C. orellanoides, etc.), and it is characterized by progressive clinical phases with a predominant kidney involvement, finally requiring renal replacement therapy in about 10% of cases. Renal damage is often late and associated with a histological picture of interstitial nephritis. Diagnosis is essentially clinical and no specific therapy has been shown to be effective in preventing and treating renal damage. Here, we describe the case of a patient with mixed wild mushroom poisoning, presenting the typical clinical signs and course of the Orellanus syndrome. This case offers us the opportunity to review the main clinical features of this severe and little-known intoxication.

Non-drug-induced nephrotoxicity

Several drugs and other compounds can induce acute and/or chronic nephrotoxicity. The goal of this study was to review clinical features of nephrotoxicity induced by 'atypical' or 'unconventional' agents, such as environmental agents (metals, minerals, animals), food agents (mushrooms, aristolochic acid, medicinal traditional herbals, dietary supplements, melamine), drugs, and other products (ethylene glycol). Nephrotoxicity varies according to local background, dependent on different food and cultural customs, as well as to differences in local fauna and flora. The incidence of such a phenomenon is not well known. Many different pathophysiological pathways are involved, and the spectrum of renal lesions is rather wide. 'Epidemic nephrotoxicity' may occur, as recently illustrated by the melamine epidemics in Chinese infants receiving powdered milk formulas; a rapid reaction to unusual increased frequency of acute kidney injury and nephrolithiasis in young children has led to a rapid analysis from international experts, with subsequent recommendations for diagnosis and care. Nephrotoxicity should be considered when there is any unexplained renal impairment, especially in children.

The fungal nephrotoxin orellanine simultaneously increases oxidative stress and down-regulates cellular defenses

Confusion of various nephrotoxic Cortinarius species with edible mushrooms occurs every year throughout Europe and North America. The toxin, orellanine (OR), accumulates selectively in renal tubular epithelium with ensuing renal failure after several days as the only clinical manifestation. This study was performed to clarify the mechanisms behind the kidney damage. Sprague-Dawley rats, 100 g bw, received various doses of purified OR ip (0-5 mg/kg bw). One week later, renal function (GFR) was determined (51Cr-EDTA), ascorbyl radicals in venous blood were analyzed using electron spin resonance, and oxidative protein damage was evaluated immunohistochemically. One OR-treated group (3.5 mg/kg) simultaneously received superoxide dismutase (SOD) targeted to tubular epithelium (HC-SOD; 10 mg/kg ip daily for 5 days). RT-PCR was used for analysis of mRNA expression of genes related to oxidative stress. OR caused a dose-dependent decrease in GFR, paralleled by increased levels of ascorbyl radicals and oxidative protein damage. Antioxidant treatment with HC-SOD decreased renal function even more and also increased tissue damage and mortality. Renal mRNA levels for key components in the antioxidative defense were strongly decreased, whereas those for several cytokines were increased. The data strongly suggest that OR nephrotoxicity in vivo is mediated by oxidative stress, including a virtual shutdown of important antioxidative enzymes. We interpret the unexpected effect of HC-SOD in terms of unbalanced SOD and catalase levels in the presence of OR, leading to massive generation of *OH and cell death.