Methylenecyclopropylglycine and hypoglycin A intoxication in three Pére David's Deers (Elaphurus davidianus) with atypical myopathy.

BACKGROUND: Hypoglycin A (HGA) and methylenecyclopropylglycine (MCPrG) from seeds/seedlings of Sycamore maple (SM, Acer pseudoplatanus) causes atypical myopathy (AM) in horses. AM was not known to occur in wild ruminants until several fatalities in milus (Elaphurus davidianus) following the ingestion of HGA in SM seeds. However, a role for MCPrG has not previously been evaluated. OBJECTIVES: To test the hypothesis that MCPrG is also a major factor in AM in milus, three milus (M1, M2, M3) from the Zoo Dresden (aged 7-11 years, 2 females and 1 male, in good nutritional condition) that developed AM were studied. METHODS: Serum, urine and methanol extracts from the liver, kidney, rumen digesta and faeces were analysed by ultrahigh-performance liquid chromatography-tandem mass spectrometry for HGA, MCPrG and for conjugates of carnitine (C) and glycine (G): Methylenecyclopropylacetyl (MCPA)-G, MCPA-C, Methylenecyclopropylformyl (MCPF)-G, MCPF-C, butyryl-C and isobutyryl-C. RESULTS: HGA in serum was high (M2 480 nmol/L; M3 460 nmol/L), but MCPrG was not. HGA and MCPrG were found in rumen and faeces extracts, and MCPrG was also identified in the liver. Metabolites of HGA and MCPrG were high in serum, urine and liver, but not in the rumen or faeces. CONCLUSIONS: This study shows that MCPrG is involved in the pathophysiology of AM in milus. The metabolism of MCPrG is considered to be faster because, after ingestion, the specific metabolites appear highly concentrated in the serum. The high toxin concentration in the liver suggests that a possible transfer into products for human consumption may pose a risk.

Potential new sources of hypoglycin A poisoning for equids kept at pasture in spring: a field pilot study.

Equine atypical myopathy in Europe results from hypoglycin A (HGA) exposure through the ingestion of samaras or seedlings of the sycamore maple tree. This pilot study aimed at better defining sources of HGA intoxication in spring. Samaras fallen on the ground and then seedlings were collected at two-week intervals from sycamore, Norway, and field maple trees over the spring 2016. In early April, rainwater from wet seedlings collected after a rainy night was harvested to be analysed. Mid-May, samaras of the box elder, common ash, and inflorescences of sycamore maples were collected on the tree. Quantification of HGA in samples was performed using high performance thin layer chromatography. Hypoglycin A was detected in all samples from sycamore including rainwater but tested negative for Norway, field maples. The samaras of the box elder found in the present study area did not contain a seed within their husk and thus tested negative. From the maximum HGA concentrations found, it may be extrapolated that at some periods and locations, about 20 g of samaras, 50 seedlings, 150 g of inforescences or 2 liters of water that has been in contact with seedlings would contain the maximum tolerated dose per day for a horse.

Hypoglycin A Content in Blood and Urine Discriminates Horses with Atypical Myopathy from Clinically Normal Horses Grazing on the Same Pasture.

Hypoglycin A (HGA) in seeds of Acer spp. is suspected to cause seasonal pasture myopathy in North America and equine atypical myopathy (AM) in Europe, fatal diseases in horses on pasture. In previous studies, this suspicion was substantiated by the correlation of seed HGA content with the concentrations of toxic metabolites in urine and serum (MCPA-conjugates) of affected horses. However, seed sampling was conducted after rather than during an outbreak of the disease. The aim of this study was to further confirm the causality between HGA occurrence and disease outbreak by seed sampling during an outbreak and the determination of i) HGA in seeds and of ii) HGA and MCPA-conjugates in urine and serum of diseased horses. Furthermore, cograzing healthy horses, which were present on AM affected pastures, were also investigated. AM-pastures in Germany were visited to identify seeds of Acer pseudoplatanus and serum (n = 8) as well as urine (n = 6) from a total of 16 diseased horses were analyzed for amino acid composition by LC-ESI-MS/MS, with a special focus on the content of HGA. Additionally, the content of its toxic metabolite was measured in its conjugated form in body fluids (UPLC-MS/MS). The seeds contained 1.7-319.8 µg HGA/g seed. The content of HGA in serum of affected horses ranged from 387.8-8493.8 µg/L (controls < 10 µg/L), and in urine from 143.8-926.4 µg/L (controls < 10 µg/L), respectively. Healthy cograzing horses on AM-pastures showed higher serum (108.8 ± 83.76 µg/L) and urine concentrations (26.9 ± 7.39 µg/L) compared to control horses, but lower concentrations compared to diseased horses. The range of MCPA-carnitine and creatinine concentrations found in diseased horses in serum and urine were 0.17-0.65 mmol/L (controls < 0.01), and 0.34-2.05 µmol/mmoL (controls < 0.001), respectively. MCPA-glycine levels in urine of cograzing horses were higher compared to controls. Thus, the causal link between HGA intoxication and disease outbreak could be further substantiated, and the early detection of HGA in cograzing horses, which are clinically normal, might be a promising step in prophylaxis.

Fatal intoxication due to ackee (Blighia sapida) in Suriname and French Guyana. GC-MS detection and quantification of hypoglycin-A.

Between 1998 and 2001 the deaths of 16 Surinamese children were recorded along the Maroni River, which forms the border between Suriname and French Guyana. After a metabolic origin was eliminated, ethnobotanical research in the field led to a hypothesis of intoxication through the ingestion of ackee. Ackee (Blighia sapida) is a large green leafy tree of West African origin. Its unripe fruit contains large quantities of two toxic molecules: hypoglycin-A and hypoglycin-B, the former being the more toxic. We have developed a GC-MS procedure allowing us to demonstrate the presence of hypoglycin-A in the gastric fluid of one of the deceased children, and to compare the content of hypoglycin-A in fruit collected on the road to Paramaribo in Suriname (5.1mg/g) with samples from Burkina Faso (8.1mg/g) and Jamaica (9.2mg/g). Field research showed the misuse of this little-known plant by Maroon witch doctors. The Bushinengue witch doctors were informed about the dangers of ackee, and no new cases have been reported to date.

Epidemic of fatal encephalopathy in preschool children in Burkina Faso and consumption of unripe ackee (Blighia sapida) fruit.

BACKGROUND: On March 21, 1998, the Regional Health Authority of Bobo-Dioulasso, Burkina Faso, asked the Centre Muraz to investigate an unexplained outbreak of epidemic fatal encephalopathy (EFE). We aimed to identify the cause of this epidemic. METHODS: We identified cases retrospectively through review of health-service records and interviews of family members, village chiefs, and local healers. Active surveillance was started in administrative divisions within the study area in April, 1998, to identify further EFE cases. We did a case-control study of households to investigate the risk from various environmental and health factors. Blood and urine samples were collected if possible and urine dicarboxylic acid concentrations measured by gas chromatography. FINDINGS: 29 cases of EFE were identified from January to May, 1998. Estimated age-specific attack rates (2-6 years) ranged from 31 to 847 per 100,000 population (p<0.001). The most common symptoms were hypotonia, vomiting, convulsions, and coma. All children died in 2-48 h. The only factor associated with EFE was the presence of ackee trees (Blighia sapida) within 100 m of households (odds ratio 5.1 [95% CI 1.8-14.7] p=0.001). Poisoning with unripe ackee fruits was suggested by urine concentrations of dicarboxylic acids four to 200 times higher in cases (n=2) than in controls (n=3). CONCLUSION: Consumption of unripe ackee fruit probably caused this epidemic and may lead to a substantial number of unexplained deaths in preschool children in west Africa every year. Educational campaigns have the potential to prevent these deaths.

Commentary on a review on the mechanism of Ackee-induced vomiting sickness

A recent review article concluded that glutamic acid probable plays a central role in the vomiting and neurological features of ackee poisoning. The present article draws attention to misconceptions in the basis of that hypothesis, and reviews important evidence suppporting a different role (AU)

Commentary on a review on the mechanism of ackee-induced vomiting sckness

A recent article concluded that glutamic acid probably plays a central role in the vomiting and neurological features of ackee poisoning. The present article draws attention to misconceptions in the basis of that hypothesis, and reviews important evidence supporting a different view

Effects of ackee fruit extracts on bronchomotor tone in rats

The unripe ackee fruit, when eaten, is known to cause serious clinical manifestations, including vomiting, hypoglycaemia and acidosis. The effects, of various extracts from the arilli of the unripe fruit (including hypoglyin-A) on the lungs from rats were examined in an in vitro preparation. All the extracts were found to induce moderately severe broncho-constriction, indicating a possible contribution of these effects to the observed toxicity of ackee (AU)

Effects of ackee fruit extracts on bronchomotor tone in rats

The unripe ackee fruit, when eaten, is known to cause serious clincial manifestations, including vomitting, hypoglycaemia and acidosis. The effects, of various extracts from the arilli of the unripe ackee fruit (including hypoglycin-A) on the lungs from rats were examined in an in vitro preparation. All the extracts were found to induce moderately severe broncho-constriction, indicating a possible contribution of these effects to the observed toxicity of ackee

A re-examination of the mechanism of ackee-induced vomiting sickness

The hypoglycemia seen in ackee poisoning almost certainly results from the presence of hypoglycin A in the aril. However, the mechanism underlying the vomiting and neurologic disorders have not been properly established. We have, in this review, re-established the latter and proposed that the vomiting and neurological features of ackee poisoning probably result from the excitotoxic properties of glutamic and aspartic acids derived directly and indirectly from ackee intake (AU)

A re-examination of the mechanism of ackee-induced vomiting sckness

The hypoglycemia seen in ackee poisoning almost certainly results from the presence of hypoglycin A in the aril. However, the mechanisms underlying the vomiting and neurological disrders have not been properly established. We have, in thes review, re-examined the latter and proposed that the vomiting of glutamic and neurological feactures of ackee poisoning probably result from the excitotoxic properties of glutamic and aspartic acids derived directly and indirectly from ackee intake

Organic aciduria in rats made resistant to hypoglycin toxicity by pretreatment with clofibrate.

1. The lethal, hypoglycaemic and hypothermic effects of hypoglycin in fasted rats are prevented if the rats had been fed on a diet containing clofibrate (0.5% w/w). 2. Injection of hypoglycin into fasted rats maintained on a standard diet caused severe prostration, hypothermia and a massive dicarboxylic aciduria [Tanaka (1972) J. Biol. Chem. 247, 7465-7478]. 3. Rats maintained on a diet containing clofibrate appeared normal after injection of hypoglycin, but had a marked dicarboxylic aciduria which was less than that induced in rats on a normal diet. 4. After administration of hypoglycin, butyryl-CoA and decanoyl-CoA, but not palmitoyl-CoA, dehydrogenase activities were strongly inhibited (80-95%) in the livers of animals on a standard diet. 5. Clofibrate feeding decreased the inhibition of these dehydrogenases to about 40-60%. 6. It was concluded that although clofibrate protects against the toxic effects of hypoglycin, some enzyme inhibitions as indicated by dicarboxylic aciduria are only partly prevented.