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Abstract
Cyclopiazonic acid (CPA) is an indol-tetramic acid mycotoxin and is produced by the nearly ubiquitous molds, Aspergillus and Penicillium. CPA produced by these molds has been identified in a number of food sources (including, but not limited to, grain, legumes, meat, milk, and cheese) and from parasitic infections of man and other animals. Few incidents of CPA mycotoxicoses have been reported because of the benign nature of the intoxication, the small amounts present, and its effects may be disguised with concurrent aflatoxicosis (some toxicity data may have been generated using aflatoxin-contaminated CPA). CPA is absorbed in the gastrointestinal tract and following oral administration; it has a half-life of approximately 30 hours and is excreted largely unchanged in the urine and feces. Cyclopiazonic acid is not considered to be a potent acute toxin as its oral LD50 in rodents is in the range of 30 to 70 mg/kg. Multiple dose studies also show a range of effects in several species and among mammalian models, the pig appears to be the most sensitive with a no-observable-effect level (NOEL) in the range of 1.0 mg/kg/day. The preponderance of evidence from the rat and other test animals supports this dose as a defensible estimate of a no effect level. The target organs of CPA toxicity appear to be muscle, hepatic tissue, and spleen, with a localization in the former, although a more apparent toxic change in the latter two. The toxicity and symptoms of CPA poisoning can be attributed to its ability to alter normal intracellular calcium flux through its inhibition of the reticular form of the Ca2+-ATPase pump. CPA was not teratogenic in mice. CPA is not considered a carcinogen and the weight of evidence militates against its characterization as a mutagen. Despite CPA-induced pathological changes ascribed to the spleen or bursa of Fabricius, there does not appear to be an effect on the immune system. In vitro studies imply a potential immunomodulatory effect of CPA, but in all of those reports very high concentrations of CPA were required and none of these findings have been supported with in vivo studies. Therefore, based on a NOEL of 1 mg/kg/day and accounting for species variation, an appropriate acceptable daily intake (ADI) would be approximately 10 μg/kg/day or 700 μg/day. In the context of human exposure, if the uppermost limit of CPA found in cheese is 4 μg/g and the average individual consumes 50 g of cheese daily, this allows an intake of 200 μg, less than one third of a traditionally established ADI.
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Affiliation(s)
- G. A. Burdock
- Burdock and Associates, Inc., Vero Beach, Florida, USA
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Sugizaki MM, Leopoldo AS, Okoshi MP, Bruno A, Conde SJ, Lima-Leopoldo AP, Padovani CR, Carvalho RF, Nascimento AFD, Campos DHSD, Nogueira CR, Cicogna AC. Severe food restriction induces myocardial dysfunction related to SERCA2 activity. Can J Physiol Pharmacol 2009; 87:666-73. [DOI: 10.1139/y09-060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies have shown that food restriction promotes myocardial dysfunction in rats. However, the molecular mechanisms that are responsible are unclear. We investigated the role of sarcoplasmic reticulum Ca2+-ATPase (SERCA2) on myocardial performance in food-restricted rats. Male Wistar–Kyoto rats, 60 days old, were fed a control or restricted diet (daily energy intake reduced to 50% of the control) for 90 days. Expression of Serca2a, phospholamban (PLB), Na+/Ca2+ exchanger (NCX), and thyroid hormone receptor (TRα1, TRβ1) mRNA was determined by quantitative PCR. SERCA2 activity was measured by using 20 µmol/L cyclopiazonic acid (CPA) in a left ventricular papillary muscle preparation during isometric contraction in basal conditions and during post-rest contraction. Serum concentrations of thyroxine (T4) and thyrotropin (TSH) were also determined. The 50%-restricted diet reduced body and ventricular weight and serum T4 and TSH levels. The interaction of CPA and food restriction reduced peak developed tension and maximum rate of tension decline (–dT/dt), but increased the resting tension intensity response during post-rest contraction. PLB and NCX mRNA were upregulated and TRα1 mRNA was downregulated by food restriction. These results suggest that food restriction promotes myocardial dysfunction related to impairment of sarcoplasmic reticulum Ca2+ uptake as a result of a hypothyroid state.
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Affiliation(s)
- Mário Mateus Sugizaki
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - André Soares Leopoldo
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Marina Politi Okoshi
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Alessandro Bruno
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Sandro José Conde
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Ana Paula Lima-Leopoldo
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Carlos Roberto Padovani
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Robson Francisco Carvalho
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - André Ferreira do Nascimento
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Dijon Henrique Salomé de Campos
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Célia Regina Nogueira
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
| | - Antonio Carlos Cicogna
- Department of Clinical and Cardiology, School of Medicine, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Biostatistics, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Morphology, Institute of Biological Sciences, UNESP State University Júlio Mesquita Filho, Botucatu, São Paulo, Brazil
- Department of Physical Education, FIB, Faculdades Integradas de Bauru, São Paulo, Brazil
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