Lower sulfurtransferase detoxification rates of cyanide in konzo-A tropical spastic paralysis linked to cassava cyanogenic poisoning

Desintoxicación de la yuca y preparación de ereba: aporte en el fortalecimiento de la seguridad alimentaria del pueblo Garífuna en Honduras

Desde la cosmovisión de la antropología alimentaria, al estudiar los orígenes de los pueblos, se asume metafóricamente que los latinoamericanos “somos hombres de maíz y de yuca”; la comunidad Garífuna de Honduras es la principal consumidora de yuca y derivados como el ereba (casabe) y sobresale en la técnica gastronómica ancestral para su elaboración, lo que promueve la soberanía alimentaria. La Agenda 2030, impone a las universidades, la necesidad de dar respuesta a los objetivos de desarrollo sostenible (ODS), varios de ellos relacionados con la alimentación. Este artículo tiene por objetivo realizar como academia, una alerta a la comunidad Garífuna hondureña sobre el consumo de la yuca y el casabe para ayudar a garantizar la seguridad y la soberanía alimentaria de esta población desprotegida y pobre de Honduras, mediante una revisión bibliográfica exhaustiva, contribuyendo así a afrontar los retos de los ODS de la Agenda 2030, teniendo en cuenta la toxicidad de la yuca, las enfermedades provocadas por la posible intoxicación respecto a su consumo y los métodos de detoxificación ancestral utilizada para hacer casabe. Palabras clave: Compuestos Cianogénicos, Comunidad Garífuna, Toxicidad, Detoxificación.

D-π-A structure fluorophore: NIR emission, response to viscosity, detection cyanide and bioimaging of lipid droplets

Intracellular viscosity, an important microenvironment factor, is closely involved in various cell processes as well as diseases. On the other hand, cyanide is one of the most hazardous chemicals for human health and environments. However, a NIR fluorescent probe for both response to viscosity and detection of cyanide remains vacant. Herein, we reported a D-π-A structure fluorophore (named CTR) which exhibited NIR emission and fluorescent enhancement response to viscosity via the molecular rotor strategy. Furthermore, CTR displayed fluorescent and colorimetric response to cyanide. Notably, test strips stained with CTR were fabricated, which could serve as an efficient and suitable cyanide test kit. Moreover, CTR could selectively accumulate in lipid droplets and visualize the metabolism of lipid droplets in live cells. These findings would provide new avenue to design fluorescent probe for effective response to viscosity, detection of cyanide, and bioimaging of lipid droplets in live cells.

One-carbon metabolism in children with marasmus and kwashiorkor

BACKGROUND

Kwashiorkor is a childhood syndrome of edematous malnutrition. Its precise nutritional precipitants remain uncertain despite nine decades of study. Remarkably, kwashiorkor's disturbances resemble the effects of experimental diets that are deficient in one-carbon nutrients. This similarity suggests that kwashiorkor may represent a nutritionally mediated syndrome of acute one-carbon metabolism dysfunction. Here we report findings from a cross-sectional exploration of serum one-carbon metabolites in Malawian children.

METHODS

Blood was collected from children aged 12-60 months before nutritional rehabilitation: kwashiorkor (N = 94), marasmic-kwashiorkor (N = 43) marasmus (N = 118), moderate acute malnutrition (N = 56) and controls (N = 46). Serum concentrations of 16 one-carbon metabolites were quantified using LC/MS techniques, and then compared across participant groups.

FINDINGS

Twelve of 16 measured one-carbon metabolites differed significantly between participant groups. Measured outputs of one-carbon metabolism, asymmetric dimethylarginine (ADMA) and cysteine, were lower in marasmic-kwashiorkor (median µmol/L (± SD): 0·549 (± 0·217) P = 0·00045 & 90 (± 40) P < 0·0001, respectively) and kwashiorkor (0·557 (± 0·195) P < 0·0001 & 115 (± 50) P < 0·0001), relative to marasmus (0·698 (± 0·212) & 153 (± 42)). ADMA and cysteine were well correlated with methionine in both kwashiorkor and marasmic-kwashiorkor.

INTERPRETATION

Kwashiorkor and marasmic-kwashiorkor were distinguished by evidence of one-carbon metabolism dysfunction. Correlative observations suggest that methionine deficiency drives this dysfunction, which is implicated in the syndrome's pathogenesis. The hypothesis that kwashiorkor can be prevented by fortifying low quality diets with methionine, along with nutrients that support efficient methionine use, such as choline, requires further investigation.

FUNDING

The Hickey Family Foundation, the American College of Gastroenterology, the NICHD, and the USDA/ARS.

A water-soluble azobenzene-dicyano pendant polymeric chemosensor for the colorimetric detection of cyanide in 100% aqueous media and food samples

A polymeric chemosensor (P1) was developed for the colorimetric detection of cyanide in aqueous media and cyanogenic food samples.

Brewing rich 2-phenylethanol beer from cassava and its producing metabolisms in yeast

BACKGROUND

Cassava is rich in nutrition and has high edible value, but the development of the cassava industry is limited by the traditional low added value processing and utilization mode. In this study, cassava tuber was used as beer adjunct to develop a complete set of fermentation technology for manufacturing cassava beer.

RESULTS

The activities of transaminase, phenylpyruvate decarboxylase and dehydrogenase in 2-phenylethanol Ehrlich biosynthesis pathway of Saccharomyces cerevisiae were higher in cassava beer than that of malt beer. Aminotransferase ARO9 gene and phenylpyruvate decarboxylase ARO10 gene were up-regulated in the late stage of fermentation, which indicated that they were the main regulated genes of 2-phenylethanol Ehrlich pathway with phenylalanine as substrate in cassava beer preparation.

CONCLUSIONS

Compared with traditional wheat beer, cassava beer was similar in the content of nutrition elements, diacetyl, total acid, alcohol and carbon dioxide, but has the characteristics of fresh fragrance and better taste. The hydrocyanic acid contained in cassava root tubes was catabolized during fermentation and compliant with the safety standard of beverage. Further study found that the content of 2-phenylethanol in cassava beer increased significantly, which gave cassava beer a unique elegant and delicate rose flavor. © 2020 Society of Chemical Industry.

Metabolic and Toxic Myelopathies

Metabolic and toxic causes of myelopathy form a heterogeneous group of disorders. In this review, we discuss the causes of metabolic and toxic myelopathies with respect to clinical presentation, pathophysiology, diagnostic testing, treatment, and prognosis. This review is organized by temporal course (hyperacute, acute, subacute, and chronic) and etiology (e.g., nutritional deficiency, toxic exposure). Broadly, the myelopathies associated with dietary toxins (neurolathyrism, konzo) and decompression sickness present suddenly (hyperacute). The myelopathies associated with heroin use and electrical injury present over hours to days (acutely). Most nutritional deficiencies (cobalamin, folate, copper) and toxic substances (nitrous oxide, zinc, organophosphates, clioquinol) cause a myelopathy of subacute onset. Vitamin E deficiency and hepatic myelopathy cause a chronic myelopathy. Radiation- and intrathecal chemotherapy-induced myelopathy can cause a transient and/or a progressive syndrome. For many metabolic and toxic causes of myelopathy, clinical deficits may stabilize or improve with rapid identification and treatment. Familiarity with these disorders is therefore essential.

Konzo risk factors, determinants and etiopathogenesis: What is new? A systematic review

Konzo is a toxico-nutritional upper motor neuron disease causing a spastic paraparesis in schoolchildren and childbearing women in some African countries. Almost a century since the first description of konzo, its underlying etiopathogenic mechanisms and causative agent remain unknown. This paper aims at refreshing the current knowledge of konzo determinants and pathogenesis in order to enlighten potential new research and management perspectives. Literature research was performed in PubMed and Web of Science databases according to the PRISMA methodology. Available data show that cassava-derived cyanide poisoning and protein malnutrition constitute two well-documented risk factors of konzo. However, observational studies have failed to demonstrate the causal relationship between konzo and cyanide poisoning. Thiocyanate, the current marker of choice of cyanide exposure, may underestimate the actual level of cyanide poisoning in konzo patients as a larger amount of cyanide is detoxified via other unusual pathways in the context of protein malnutrition characterizing these patients. Furthermore, the appearance of konzo may be the consequence of the interplay of several factors including cyanide metabolites, nutritional deficiencies, psycho-emotional and geo-environmental factors, resulting in pathophysiologic phenomena such as excitotoxicity or oxidative stress, responsible for neuronal damage that takes place at sparse cellular and/or subcellular levels.

Dietary exposure and risk assessment of cyanide via cassava consumption in Chinese population

The intake of cassava would probably induce adverse health effects since there are toxic cyanide in cassava. However, the risk assessment of cassava consumption has not been reported in China. Therefore, this paper aimed to evaluate the dietary risks of cassava cyanide and proposed a maximum residue limit (MRL) for cyanogenic glycosides (CNGs) in cassava. The retention rate of CNGs and CN^- were 61% and 11% after boiling, respectively. The acute dietary exposure of CN^- and CNGs were 0.6-fold and 1.7-fold of acute risk reference dose, respectively. There was no chronic health risk across all populations concerning cassava consumption. The MRL of CNGs was proposed as 200 mg/kg in cassava. Risk assessment of cyanide for foods rich in CNGs was suggested to be based on CNGs quantification rather than that of CN^-.

Motor control and cognition deficits associated with protein carbamoylation in food (cassava) cyanogenic poisoning: Neurodegeneration and genomic perspectives

A case-control design determined whether konzo, an upper motoneuron disease linked to food (cassava) toxicity was associated with protein carbamoylation and genetic variations. Exon sequences of thiosulfate sulfurtransferase (TST) or mercaptopyruvate sulfurtransferase (MPST), plasma cyanide detoxification rates, and 2D-LC-MS/MS albumin carbamoylation were assessed in 40 children [21 konzo-affected and 19 putatively healthy controls, mean (SD) age: 9.2 (3.0) years] subjected to cognition and motor testing using the Kaufman Assessment Battery and the Bruininks/Oseretsky Test, respectively. Konzo was significantly associated with higher levels of carbamoylated peptides 206-219 (LDELRDEGKASSAK, pep1) after adjusting for age, gender, albumin concentrations and BUN [regression coefficient: 0.03 (95%CI:0.02-0.05), p = 0.01]. Levels of pep1 negatively correlated with performance scores at all modalities of motor proficiency (r = 0.38 to 0.61; all p < 0.01) or sequential processing (memory)(r = - 0.59, p = 0.00) and overall cognitive performance (r = - 0.48, p = 0.00) but positively with time needed for cyanide detoxification in plasma (r = 0.33, p = 0.04). Rare potentially damaging TST p.Arg206Cys (rs61742280) and MPST p.His317Tyr (rs1038542246) heterozygous variants were identified but with no impact on subject phenotypes. Protein carbamoylation appears to be a reliable marker for cassava related neurodegeneration.

Chronic consumption of cassava juice induces cellular stress in rat substantia nigra

OBJECTIVES

Cassava (Manihot esculenta Crantz) contains cyanogenic glycosides (linamarin and lotaustralin) that have been associated with neurological disorders in humans and rats. In basal ganglia, the dopaminergic neurons of substantia nigra pars compacta (SNpc) show high cytotoxic susceptibility; therefore, the chronic consumption of cassava (CCC) could induce neurodegeneration in SNpc. In this study we examine the impact of CCC on the integrity of the nigrostriatal system, including apoptosis and microgliosis.

MATERIALS AND METHODS

Male Wistar rats were administered cassava juice daily (3.57 g/kg and 28.56 g/kg, per os) or linamarin (0.15 mg/ml, IP), and its effects were evaluated in rota-rod and swim tests at days 7, 14, 21, 28, and 35 of administration. In SNpc, oxidative/nitrosative stress was determined by malondialdehyde/4-hydroxyalkenals (MDA-4-HAD) and nitrite contents. Tyrosine hydroxylase immunoreactivity (TH-IR) was evaluated in SNpc, neostriatum (NE), and nucleus accumbens (NA). Apoptosis and microgliosis were determined by active-caspase-3 (C3) and CD11b/c (OX42) expression in the medial region of SNpc.

RESULTS

Chronic administration of cassava juice, or linamarin, increased motor impairment. The rats that received 28.56 g/kg cassava showed increased MDA-4-HAD content in SNpc and nitrite levels in NE with respect to controls. Significant loss of TH-IR in SNpc, NE, and NA was not found. The 28.56 g/kg cassava administration produced dopaminergic atrophy and microgliosis, whereas linamarin induced hypertrophy and C3-related apoptosis in SNpc.

CONCLUSION

CCC induces cellular stress on dopaminergic neurons, which could contribute to motor impairment in the rat.

Preclinical and clinical research on the toxic and neurological effects of cassava (Manihot esculenta Crantz) consumption

Cassava (Manihot esculenta Crantz) is a tropical plant that is used as fresh food, processed food, or raw material for the preparation of flours with high nutritional value. However, cassava contains cyanogenic glycosides, such as linamarin and lotaustralin, that can trigger severe toxic effects and some neurological disorders, including motor impairment, cognitive deterioration, and symptoms that characterize tropical ataxic neuropathy and spastic epidemic paraparesis (Konzo). These alterations that are associated with the consumption of cassava or its derivatives have been reported in both humans and experimental animals. The present review discusses and integrates preclinical and clinical evidence that indicates the toxic and neurological effects of cassava and its derivatives by affecting metabolic processes and the central nervous system. An exhaustive review of the literature was performed using specialized databases that focused on the toxic and neurological effects of the consumption of cassava and its derivatives. We sought to provide structured information that will contribute to understanding the undesirable effects of some foods and preventing health problems in vulnerable populations who consume these vegetables. Cassava contains cyanogenic glycosides that contribute to the development of neurological disorders when they are ingested inappropriately or for prolonged periods of time. Such high consumption can affect neurochemical and neurophysiological processes in particular brain structures and affect peripheral metabolic processes that impact wellness. Although some vegetables have high nutritional value and ameliorate food deficits in vulnerable populations, they can also predispose individuals to the development of neurological diseases.

Determination of Cyanide in Water and Food Samples Using an Efficient Naphthalene-Based Ratiometric Fluorescent Probe

Monitoring cyanide levels in water and food samples is crucial. Herein, we rationally developed a simple and efficient fluorescent probe for cyanide determination. The probe displayed selective ratiometric fluorescent response to cyanide. In addition, after treatment with cyanide, the fluorescence ratios (I ₅₀₉/I ₄₆₆) exhibited a good linearity with cyanide concentration in the range of 0-60 μM, and the detection limit was determined to be 0.23 μM (S/N = 3). Significantly, the practical application demonstrated that the probe was able to quantitatively detect cyanide concentration in natural water samples. Monitoring of endogenous cyanide in cherry nut by the probe was also successfully conducted. Notably, upon fabrication of test strips, the probe could be conveniently utilized for field measurement of cyanide in bitter almond without relying on sophistical instruments. Furthermore, the cyanide in potato tissues was determined for the first time by means of fluorescence imaging.

Dietary cyanogen exposure and early child neurodevelopment: An observational study from the Democratic Republic of Congo

Background

Dietary cyanogen exposure from ingesting bitter (toxic) cassava as a main source of food in sub-Saharan Africa is related to neurological impairments in sub-Saharan Africa. We explored possible association with early child neurodevelopmental outcomes.

Methods

We undertook a cross-sectional neurodevelopmental assessment of 12–48 month-old children using the Mullen Scale of Early Learning (MSEL) and the Gensini Gavito Scale (GGS). We used the Hopkins Symptoms Checklist-10 (HSCL-10) and Goldberg Depression Anxiety Scale (GDAS) to screen for symptoms of maternal depression-anxiety. We used the cyanogen content in household cassava flour and urinary thiocyanate (SCN) as biomarkers of dietary cyanogen exposure. We employed multivariable generalized linear models (GLM) with Gamma link function to determine predictors of early child neurodevelopmental outcomes.

Results

The mean (SD) and median (IQR) of cyanogen content of cassava household flour were above the WHO cut-off points of 10 ppm (52.18 [32·79]) and 50 (30–50) ppm, respectively. Mean (SD) urinary levels of thiocyanate and median (IQR) were respectively 817·81 (474·59) and 688 (344–1032) μmole/l in mothers, and 617·49 (449·48) and 688 (344–688) μmole/l in children reflecting individual high levels as well as a community-wide cyanogenic exposure. The concentration of cyanide in cassava flour was significantly associated with early child neurodevelopment, motor development and cognitive ability as indicated by univariable linear regression (p < 0.05). After adjusting for biological and socioeconomic predictors at multivariable analyses, fine motor proficiency and child neurodevelopment remained the main predictors associated with the concentration of cyanide in cassava flour: coefficients of -0·08 to -.15 (p < 0·01). We also found a significant association between child linear growth, early child neurodevelopment, cognitive ability and motor development at both univariable and multivariable linear regression analyses coefficients of 1.44 to 7.31 (p < 0·01).

Conclusion

Dietary cyanogen exposure is associated with early child neurodevelopment, cognitive abilities and motor development, even in the absence of clinically evident paralysis. There is a need for community-wide interventions for better cassava processing practices for detoxification, improved nutrition, and neuro-rehabilitation, all of which are essential for optimal development in exposed children.

Early and middle childhood developmental, cognitive, and psychiatric outcomes of Malawian children affected by retinopathy positive cerebral malaria

The objective is to determine the short -and long-term developmental, cognitive, and psychiatric effects of retinopathy positive cerebral malaria (CM-R) among young children in a prospective study assessing them around the onset of disease and again 2 years at preschool and again at school age. In total, 109 children were recruited from the Queen Elizabeth Central Hospital in Blantyre, Malawi, (N = 49) with CM-R and non-malaria controls  (N = 60). Children were assessed for overall motor, language, and social skills using the Malawi Developmental Assessment Tool (MDAT) at preschool age. At school age, the same children were then given the Kaufman Assessment Battery for Children, second edition (KABC-II), which assessed global cognitive performancememory, and learning; as well as the Test of Variables of Attention (TOVA), which assessed attention. The Achenbach Child Development Checklist (CBCL) was administered at both time points to assess emotional and behavioral patterns. Controls scored significantly better on all KABC-II global domains as well as on the mental processing index than their CM-R group counterparts, but showed no performance differences in the TOVA and CBCL assessments at school age, or in the MDAT and CBCL assessments at preschool age. The MDAT total score was significantly correlated with the KABC-II sequential processing, learning, and mental processing index among CM-R survivors but not among controls. Persisting neurocognitive effects of CM can be captured with the KABC-II at school age. The MDAT at preschool age is correlated with the KABC-II among CM-R survivors and can be used to capture early emerging developmental deficits due to CM-R.