Myo- and cardiotoxic effects of the wild winter mushroom (Flammulina velutipes) on mice

Abstract

Rhabdomyolysis (destruction of striated muscle) is a novel form of mushroom poisoning in Europe and Asia indicated by increased circulating creatine kinase levels. Particular wild fungi have also been reported to induce elevated creatine kinase activities in mice. Flammulina velutipes (enokitake or winter mushroom) is one of the most actively cultivated mushroom species globally. As it is marketed as a medicinal mushroom and functional food, it is important to examine whether it could induce potentially harmful health effects similar to some previously studied edible fungi. The present study examined the effects of F. velutipes consumption on the plasma clinical chemistry, hematology, and organ histology of laboratory mice. Wild F. velutipes were dried, pulverized, mixed with a regular laboratory rodent diet, and fed to the animals at 0, 3, 6, or 9 g/kg body mass/day for five days ( n = 6/group). F. velutipes consumption caused increased activities of plasma creatine kinase and the MB-fraction of creatine kinase at 6-9 g/kg/d, indicating potentially deleterious effects on both skeletal and cardiac muscle. The plasma total and high-density lipoprotein cholesterol concentrations (at 9 g/kg/d) and white blood cell and lymphocyte counts (at 6-9 g/kg/d) decreased. Although the cholesterol-lowering properties of F. velutipes can be beneficial, the previously unexamined, potentially hazardous side effects of mushroom consumption (myo- and cardiotoxicity) should be thoroughly investigated before recommending this mushroom species as a health-promoting food item. Impact statement This work is important to the field of functional foods, as it provides novel information about the potential myo- and cardiotoxic properties of an edible mushroom, Flammulina velutipes. The results are useful and of importance because F. velutipes is an actively cultivated mushroom and marketed as a health-promoting food item. The findings contribute to the understanding of the complexity of the balance between the beneficial and potentially harmful effects of mushroom consumption.

Comment on “Study of biological activity of Tricholoma equestre fruiting bodies and their safety for human”

“…Lower but still high dosing (equivalent to 3 kg of mushrooms eaten every day) did not cause significant effects in studied animals [6,7]. Similar effects in mice were observed after administration of similarly high doses of various other mushroom species with well-established edibility such as Lentinula edodes, Cantharellus cibarius, Albatrellus ovinus, Leccinium versipelle, Flammulina velutipes, and Imleria badia [5,6,14,15]. This implies that the observed reaction may be unrelated to specific species and cannot be used as an isolated evidence to support a notion that T. equestre is a cause or rhabdomyolysis.…”

Is the Yellow Knight Mushroom Edible or Not? A Systematic Review and Critical Viewpoints on the Toxicity of Tricholoma equestre

“…have all increased plasma creatine kinase activity in mice at 9 g/kg bw/day administered over 5 consecutive days to levels comparable to that observed in animals treated with similar doses of T. equestre (Nieminen et al., , ; Nieminen, Kärjä, & Mustonen, ). More recently, oral administration of 6 g/kg bw/day of Flammulina velutipes (Curtis) Singer has also been found to increase plasma concentration of total creatine kinase and its MB isoenzyme (Mustonen et al., ). Importantly, regardless of dosage and tested mushroom species only a modest increase in creatine kinase levels (up to several hundred U/L) was observed, particularly when compared to results observed in dystrophic mice or those treated with agents known to induce rhabdomyolsysis (up to few thousand U/L) (Osaki et al., ; van Putten et al., ).…”

The Yellow Knight Fights Back: Toxicological, Epidemiological, and Survey Studies Defend Edibility of Tricholoma equestre

“…Rhabdomyolysis has also been reported in humans following consumption of white button mushroom species Agaricus bisporus [ 19 ] or species from the Boletus and Leccinum genera [ 20 ]. Moreover, the in vivo model applied to confirm T. equestre toxicity does not provide convincing evidence as significantly increased plasma CK concentrations have also been noted in mice fed with high doses of edible mushrooms including Boletus edulis , Lentinula edodes , Cantharellus cibarius , Albatrellus ovinus , Leccinium versipelle , Imleria badia, and Flammulina velutipes [ 7 , 8 , 21 , 22 ]. Yet their edibility and general safety has never been questioned and no warnings have ever been released.…”