Variaciones morfológicas de la glándula submandibular en ratas obesas por acción de glutamato monosódico / Morphological variations of the submandibular gland in obese rats by the action of monosodium glutamate

Este estudio tuvo como objetivo demostrar la existencia de variaciones morfológicas en el tejido conectivo de la glándula submandibular de ratas obesas expuestas a glutamato monosódico (GMS). Se utilizaron 12 ratas Sprague Dawley machos recién nacidas (6 ratas para el grupo 1, control; 6 ratas para el grupo 2 (GMS), 4 mg/g de glutamato monosódico de peso (5 dosis) mantenidas por 16 semanas respectivamente con una dieta y agua ad libitum. En el estudio se realizó un análisis estereológico e histológico, demostrándose una variación en el tejido conectivo presentando una disminución del volúmen glandular, mayor fibrosis, y disminución de adipocitos a nivel periférico siendo reemplazado por tejido rico en colágeno. Los vasos sanguíneos observados a nivel estereológico no presentan mayores cambios en cuanto a volumen, superficie y área.

SUMMARY: This study aims to demonstrate the existence of morphological variations in the connective tissue of the submandibular gland of obese rats exposed to MSG. Twelve male newborn Sprague Dawley rats were used (6 rats for group 1, control; 6 rats for group 2 (MSG), 4 mg/g of monosodium glutamate of weight (5 doses) maintained for 16 weeks respectively with a diet and water ad libitum. In the study, a stereological and histological analysis was carried out, demonstrating a variation in the connective tissue, presenting a decrease in the glandular volume, greater fibrosis, and a decrease in adipocytes at the peripheral level, being replaced by tissue rich in collagen. Blood cells observed at the stereological level do not present major changes in terms of volume, surface and area, but in the histological study greater vascularization is observed.

Alterations in APC, BECN1, and TP53 gene expression levels in colon cancer cells caused by monosodium glutamate / Alterações nos níveis de expressão gênica APC, BECN1 e TP53 em células de câncer de cólon causadas por glutamato monossódico

Colorectal cancer (CRC) is a disease with high incidence worldwide. As of 2018, it is the second leading cause of cancer deaths in the world. In Saudi Arabia, the incidence of this disease has been increasing in the younger population. Both genetic and lifestyle factors may have contributed to its increased incidence and pathogenesis. Monosodium glutamate (MSG) is a food flavor enhancer that can be found in many commercial foods, and it can sometimes be used as a substitute to table salt. MSG has been investigated for its possible genotoxicity, yielding controversial results. In the present study, the effect of MSG on cell viability and its effect on expression of APC, BECN1, and TP53 genes in SW620 and SW480 colon cancer cell lines were studied. TP53 is a tumor suppressor gene that functions in modifying DNA errors and/or inducing apoptosis of damaged cells, and both APC and BECN1 genes are involved in CRC and are of importance in cellular growth and metastasis. Cancer cell viability was analyzed using MTT assay, and the results showed a significant increase in the number of viable cells after 24h of treatment with MSG with different concentrations (0.5, 1.0, 10, 50, and 100mM). Moreover, gene expression results showed a significant increase in the expression levels of APC and BECN1 under specified conditions in both cell lines; conversely, TP53 showed a significant decrease in expression in SW620 cells. Thus, it can be concluded that MSG possibly confers a pro-proliferative effect on CRC cells.

O câncer colorretal (CCR) é uma doença com alta incidência mundial. Desde 2018, é a segunda principal causa de mortes por câncer no mundo. Na Arábia Saudita, a incidência dessa doença vem aumentando na população mais jovem. Tanto fatores genéticos quanto de estilo de vida podem ter contribuído para o aumento da sua incidência e patogênese. O glutamato monossódico (MSG) é um intensificador de sabor de alimentos que pode ser encontrado em muitos alimentos comerciais e às vezes pode ser usado como um substituto do sal de cozinha. O MSG tem sido investigado por sua possível genotoxicidade, produzindo resultados controversos. Neste estudo, foram estudados o efeito do MSG na viabilidade celular e seu efeito na expressão dos genes APC, BECN1 e TP53 em linhas de células de câncer de cólon SW620 e SW480. TP53 é um gene supressor de tumor que atua modificando erros de DNA e/ou induzindo apoptose de células danificadas, estando os genes APC e BECN1 envolvidos no CRC e sendo importantes no crescimento celular e metástase. A viabilidade das células cancerosas foi analisada por meio do ensaio MTT, e os resultados mostraram um aumento significativo no número de células viáveis após 24 h de tratamento com MSG em diferentes concentrações (0,5; 1,0; 10; 50 e 100mM). Além disso, os resultados da expressão gênica mostraram um aumento significativo nos níveis de expressão de APC e BECN1 sob condições especificadas em ambas as linhagens celulares. Por outro lado, TP53 mostrou uma diminuição significativa na expressão em células SW620. Assim, pode-se concluir que, possivelmente, o MSG confere um efeito pró-proliferativo às células CRC.

Vitamin E suppresses aortic ultrastructural alterations induced by toxic doses of monosodium glutamate / La vitamina E suprime las alteraciones ultraestructurales aórticas inducidas por dosis tóxicas de glutamato monosódico

SUMMARY: An association between certain food additives and chronic diseases is reported. Current study determined whether administering toxic doses of the food additive monosodium glutamate (MSG) into rats can induce aortopathy in association with the oxidative stress and inflammatory biomarkers upregulation and whether the effects of MSG overdose can be inhibited by vitamin E. MSG at a dose of (4 mg/kg; orally) that exceeds the average human daily consumption by 1000x was administered daily for 7 days to the rats in the model group. Whereas, rats treated with vitamin E were divided into two groups and given daily doses of MSG plus 100 mg/ kg vitamin E or MSG plus 300 mg/kg vitamin E. On the eighth day, all rats were culled. Using light and electron microscopy examinations, a profound aortic injury in the model group was observed demonstrated by damaged endothelial layer, degenerated smooth muscle cells (SMC) with vacuoles and condensed nuclei, vacuolated cytoplasm, disrupted plasma membrane, interrupted internal elastic lamina, clumped chromatin, and damaged actin and myosin filaments. Vitamin E significantly protected aorta tissue and cells as well as inhibited MSG-induced tissue malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). The highest used vitamin E dosage was more effective. Additionally, a significant correlation was observed between the aortic injury degree and tissue MDA, TNF-α, IL-6, and superoxide dismutase (SOD) levels (p=0.001). Vitamin E effectively protects against aortopathy induced by toxic doses of MSG in rats and inhibits oxidative stress and inflammation.

RESUMEN: Se reporta una asociación entre ciertos aditivos alimentarios y enfermedades crónicas. El objetivo de este estudio fue determinar si la administración de dosis tóxicas del aditivo alimentario glutamato monosódico (MSG) en ratas puede inducir aortopatía en asociación con el estrés oxidativo y la regulación positiva de los biomarcadores inflamatorios y si el efecto de una sobredosis de MSG se puede inhibir con vitamina E. Se administró MSG diariamente durante 7 días una dosis de (4 g/kg; por vía oral) que excede el consumo diario humano promedio, en 1000x a las ratas del grupo modelo. Mientras que las ratas tratadas con vitamina E se dividieron en dos grupos y se administraron dosis diarias de MSG más 100 mg/kg de vitamina E o MSG más 300 mg/kg de vitamina E. Todas las ratas fueron sacrificadas en el octavo día. Usando exámenes de microscopía óptica y electrónica, se observó una lesión aórtica profunda en el grupo modelo demostrada por una capa endotelial dañada, células musculares lisas degeneradas (SMC) con vacuolas y núcleos condensados, citoplasma vacuolado, membrana plasmática rota, lámina elástica interna interrumpida, cromatina agrupada y filamentos de actina y miosina dañados. La vitamina E protegió significativamente el tejido y las células de la aorta, además de inhibir el malondialdehído tisular (MDA) inducido por MSG, la interleucina-6 (IL-6) y el factor de necrosis tumoral alfa (TNF-α). La dosis más alta de vitamina E utilizada fue más efectiva. Además, se observó una correlación significativa entre el grado de lesión aórtica y los niveles tisulares de MDA, TNF-α, IL-6 y superóxido dismutasa (SOD) (p=0,001). La vitamina E efectivamente protege contra la aortopatía inducida por dosis tóxicas de MSG en ratas e inhibe el estrés oxidativo y la inflamación.

Use of monosodium glutamate in foods: the good, the bad, and the controversial side / Uso de glutamato monossódico em alimentos: o bom, o mau e o lado controverso

Introduction: Monosodium glutamate (MSG) is known as a flavor-enhancing compound and also the fifth basic taste (umami). About the safety of using MSG as a food additive, some studies show indications that there is no threat and others showthe opposite. There is no consensus about the advantages and disadvantages of using MSG. Objective: To systematically review studies in the international literature on the knowledge of the pros and cons of using glutamate in food. Methods: Systematic review of studies published in journals indexed in ScienceDirect and PubMed databases. Articles published until 2020 were included. The aspects involving the advantages and disadvantages were discussed, as well as the health risks related to the MSG intake from diet. Results: The revised studies showed that MSG can reduce the amount of sodium in foods without modifying flavor. Although authorities indicate that MSG is safe for human consumption, some studies highlight that health risk is real. The use of MSG is still controversial because there are some misunderstandings in the applied amounts of MSG absorption and metabolism. Conclusion: MSG is widely applied in industrial and homemade food. The need for further studies is crucial, and aspects such as metabolism and amounts of MSG effectively consumed must be better evaluated.

Alteraciones histológicas hepáticas provocadas por la ingesta crónica de glutamato monosódico / Histological liver changes caused by chronic intake of monosodium glutamate

ntroducción. El glutamato es un aminoácido que está implicado en numerosas reacciones relacionadas con el metabolismo hepático, por lo que la sobreactivación de los receptores de glutamato por acción de la ingesta de glutamato monosódico (GMS) proveniente de la dieta, podría llevar a daño del tejido hepático. Este estudio se realizó con el objetivo de evaluar los cambios histológicos producidos en el hígado de ratas sometidas a la administración crónica de GMS. Metodología. Se trabajó con dos lotes de animales, uno experimental y otro control, cada uno de ellos constituido por seis ratas machos cepa Wistar de cinco semanas de edad. Al grupo experimental se le administró diariamente 0,1 g de queso de bajas calorías que contenía GMS monohidrato de 99% de pureza (grado alimentario puro), diluido en 50 µL de agua desionizada (0,3 g/100 g de peso corporal). Al grupo control se le administró la misma cantidad de sodio que el que contenía el GMS del grupo tratado, pero bajo la forma de NaCl. Al concluir el tratamiento, las ratas pertenecientes a ambos grupos se pesaron y sacrificaron, y se les extrajo el hígado para el estudio histológico. Se obtuvieron cortes histológicos que fueron coloreados con hematoxilina-eosina, PAS y coloración con tricrómico de Masson. El análisis de los cortes histológicos se llevó a cabo por observación directa en microscopio óptico con objetivo de 40x. Resultados. Se observó en general, conservación y apariencia normal de las características histológicas de los acinos hepáticos en el grupo control, en tanto que el hígado de las ratas tratadas con GMS presentó diferentes grados de degeneración hidrópica, cantidades variables de cuerpos hialinos eosinófilos, infiltración inflamatoria de células mononucleares y necrosis focal, principalmente en la zona 1 del acino hepático. Conclusión. Los resultados encontrados permiten aportar evidencias en torno a las alteraciones histopatológicas que la ingesta crónica de GMS provoca sobre el tejido hepático. Se recomienda alertar a la población para reducir la ingesta de alimentos que poseen GMS como saborizante.

Introduction. Glutamate is an amino acid that is involved in numerous reactions related to liver metabolism, so the overactivation of glutamate receptors due to the ingestion of monosodium glutamate (MSG) from the diet could lead to liver tissue damage. The aim of this study was to evaluate the histological changes produced in the liver of rats subjected to chronic administration of MSG. Methodology. Two sets of animals were used, an experimental and a control group, each consisting of six five-week-old Wistar male rats. The experimental group was administered 0.1 g of low-calorie cheese containing 99% purity MSG monohydrate (pure food grade) diluted in 50 µL of deionized water (0.3 g/100 g of weight) daily. The control group was administered the same amount of sodium as that contained in the MSG of the treated group, but in the form of NaCl. At the end of the treatment, the rats belonging to both groups were weighed and sacrificed, and their liver was removed for histological analysis. Histological sections were obtained and stained with hematoxylineosin, PAS and Masson's trichrome. The analysis of the histological sections was carried out by direct observation with an optical microscope and a 40x objective. Results. In general, conservation and normal appearance of the histological characteristics of the liver acini were observed in the control group, while the liver of the rats treated with MSG presented different degrees of hydropic degeneration, variable amounts of eosinophilic hyaline bodies, inflammatory infiltration of mononuclear cells and focal necrosis, that affected mainly zone 1 of the liver acinus. Conclusion. The results allow us to provide evidence about the histopathological alterations that the chronic intake of MSG causes on the liver tissue. It is recommended to alert the population to reduce the intake of foods that have GMS for flavoring.

Evaluación semicuantitativa de los microelementos del esmalte en un modelo de obesidad inducido por glutamato monosódico en ratas / Semi-quantitative evaluation of enamel microelements in an obesity model induced by monosodium glutamate in rats

RESUMEN: En la actualidad, existen múltiples modelos experimentales de obesidad, unos de ellos es la utilización de glutamato monosódico (GMS), un potenciador del sabor ampliamente utilizado en industria alimentaria. Este GMS ha sido relacionado con obesidad, diabetes, insulino resistencia, así como en alteraciones en múltiples órganos, tales como testículos, riñón e hígado, entre otros. Ha sido reportado el efecto del GMS en estructuras orales, tales como las glándulas salivales, alterando su morfología y función. La relación del efecto del GMS frente a tejidos dentarios no ha sido reportada, siendo esto relevantes debido a la información que proporciona a disciplinas tales como arqueología científica, identificación forense, paleoecología y odontología. El objetivo del estudio fue observar la modificación de los elementos en la superficie dental, en un modelo de obesidad inducida por GMS, en ratas. Se utilizaron 12 ratas neonatas Sprague Dawley machos, divididas en dos grupos según exposición a GMS (Grupo Control y Grupo GMS 1: 4 mg/g peso de GMS, 5 dosis, mantenidas 16 semanas. Fue calculado el índice de masa corporal (IMC) e Índice de Lee, además de ser analizados el porcentaje de masa de los elementos C, O, Na, P, Ca, Fe y K en la superficie dental, mediante análisis semicuantitativo. Los resultados indican que GMS indujo obesidad en las ratas, así como alteraciones en los porcentajes de masa de los elementos en la superficie dental, evidenciándose disminución de Ca, P y O, además de aumentos en C y Fe. Según reportes previos, la obesidad inducida por GMS, causa alteraciones en secreción y composición salival, elemento íntimamente relacionado con la composición del esmalte, lo que vendría a explicar nuestros resultados. Entender la composición superficial del esmalte superficial podría ayudarnos a comprender de mejor manera la relación entre caries dentaria y obesidad.

SUMMARY: Monosodium glutamate (MSG) is a flavor enhancer widely used in the food industry. It has been associated with obesity, diabetes, insulin resistance, as well as alterations in multiple organs, such as testicles, kidney, liver, among others. While its effect on oral structures such as the salivary glands has been reported, the impact on dental tissues has not been described. Since this information is also relevant in fields such as forensic identification, palaeoecology and dentistry, the objective of the study was to observe alterations on the tooth surface in a model of obesity in rats induced by MSG. Twelve neonate male Sprague Dawley rats were used, divided into two groups according to MSG exposure (Control Group and MSG1 Group: 4 mg / g weight of MSG, 5 doses were maintained for 16 weeks. Body mass index (BMI) and Lee's index as well as mass percentage of elements C, O, Na, P, Ca, Fe and K on the tooth surface were evaluated by semi-quantitative analysis. In addition to increases in C and Fe, results indicate that MSG induced obesity and alterations in the percentages of mass on the tooth surface in rats, showing a decrease in Ca, P and O, According to previous reports, MSG induced obesity causes alterations in secretion and salivary composition, an aspect closely related to enamel composition, thus explaining our results. Enhanced knowledge of enamel surface composition may help improve our understanding of the relationship between dental caries and obesity.

Indicadores metabólicos y de estrés oxidativo en ratas con obesidad inducida con glutamato monosódico / Metabolic and oxidative stress markers in rats with monosodium glutamate-induced obesity

Introducción: La obesidad, especialmente la visceral, constituye un factor de riesgo principal para múltiples enfermedades tales como: diabetes Mellitus tipo 2, enfermedades cardiovasculares, aterosclerosis, dislipidemias, enfermedad por hígado graso no alcohólico y cáncer. Se plantea que el estrés oxidativo podría ser el factor causal común de las comorbilidades asociadas a la obesidad. Objetivo: Evaluar el balance prooxidante/antioxidante en ratas con obesidad inducida con glutamato monosódico. Material y Métodos: Ratas Wistar hembras recibieron glutamato monosódico (4 mg/g de peso corporal) para inducir obesidad o NaCl 0,9 por ciento (Controles) subcutáneamente en período neonatal. A los 90 días, se confirmó la obesidad. Se les practicó eutanasia a los 180 días para la obtención de sangre e hígado para la determinación de marcadores bioquímicos. Resultados: Las ratas obesas presentaron niveles incrementados de TAG, AU, insulina e índices HOMA y TyG. Se constataron mayores concentraciones de nitratos y nitritos, productos avanzados de la oxidación de proteínas y productos de oxidación de la 2-desoxirribosa en el ADN en las ratas obesas. Conclusiones: Se concluye que la obesidad inducida con glutamato monosódico reproduce las principales alteraciones metabólicas asociadas a la obesidad visceral humana, dentro de las que se incluye el estrés oxidativo. Este modelo podría ser útil en la evaluación de estrategias terapéuticas para prevenir o disminuir complicaciones asociadas a la obesidad(AU)

Introduction: Obesity, especially visceral, is a major risk factor for several diseases such as Type 2 diabetes mellitus, cardiovascular diseases, atherosclerosis, dyslipidemia, non-alcoholic fatty liver disease, and cancer. Oxidative stress may be a unifying mechanism for the development of major obesity-related comorbidities. Objective: To evaluate the prooxidant-antioxidant balance in monosodium glutamate-induced obesity in Wistar rats (MSG- obese rats). Material and Methods: Female Wistar rats received subcutaneous (sc) injections of monosodium glutamate solution (4 mg/g of body weight) or vehicle (NaCl 0,9 percent; control) to induce obesity during the neonatal period. At 90 days of life, obesity was determined. At 180 days of life, rats were anesthetized and killed to obtain blood and liver samples for the determination of biochemical markers. Results: MSG obese rats presented significantly higher triglycerides, uric acid and insulin levels, as well as elevated HOMA and TyG indexes. Increased concentrations of nitrate and nitrite, 2-deoxyribose oxidation products and advanced oxidation protein products levels were observed in obese rats. Conclusions: Obesity induced by monosodium glutamate reproduces the main metabolic alterations associated with human visceral obesity, among which oxidative stress is included. This model may be useful for the evaluation of therapeutic strategies to prevent or decrease complications associated with obesity(AU)

Monosodium glutamate alters the function and morphology of the parotid gland in Sprague Dawley rats / Glutamato monosódico altera la función y morfología de la glándula parótida en ratas Sprague Dawley

Monosodium glutamate (MSG) is a flavor enhancer widely used in the food industry, with obesogenic properties, in addition to causing alterations in the oral cavity. The aim of the study was to observe the morphofunctional changes in the parotid gland after the administration of MSG in rats. 18 newborn male Sprague Dawley rats were used, divided into three groups (Control group; MSG1 group: 4 mg/g weight of monosodium glutamate, 5 doses, kept for 8 weeks, and MSG2 group: 4 mg/g weight of MSG, 5 doses, kept for 16 weeks). The body mass index (BMI) was calculated, and the salivary flow, pH, a-amylase activity, Na, Cl, K and Ca were analyzed by quantitative analysis. After euthanasia by ketamine/xylazine overdose, parotid volume was analyzed and stereology was performed. MSG administration caused an increase in BMI and a decrease in parotid volume as well as a reduction in salivary flow and pH and an increase in a-amylase activity, also increasing the salivary sodium and chlorine levels. Alterations in the normal stereological parameters of the gland were observed. Exposure to MSG caused morphofunctional alterations at parotid gland.

El glutamato monosódico (MSG), es un potenciador del sabor ampliamente utilizado en la industria alimentaria. Diversos estudios han propuesto la relación entre éste y el desarrollo de obesidad, además de provocar alteraciones en la cavidad oral. El objetivo del estudio fue observar los cambios morfofuncionales a nivel de la glándula parótida, posterior a la administración de MSG en ratas. Se utilizaron 18 ratas neonatas Sprague Dawley machos, divididas en tres grupos según su tiempo de exposición y dosis a MSG (Grupo Control, Grupo MSG1: 4 mg/g peso de glutamato monosódico, 5 dosis, mantenidas 8 semanas, Grupo MSG2: 4 mg/g peso de MSG, 5 dosis, mantenidas 16 semanas. Fue calculado el índice de masa corporal (BMI), además de ser analizado el flujo salival, pH, actividad de α-amilasa, y Na, Cl, K y Ca mediante análisis semicuantitativo. Luego de la eutanasia por sobredosis de ketamina/xilasina, las glándulas parótidas fueron extraídas y analizado su volumen y fueron procesadas para histología, y estudio estereológico. La administración de MSG causó aumento en BMI y disminución del volumen parotídeo, además de disminución del flujo y pH salival, así como aumento en actividad de la a-amilasa, aumentando además los niveles de sodio y cloro salival. Fueron observadas alteraciones a nivel de los parámetros estereológicos normales de la glándula. La exposición a MSG causó alteraciones morfofuncionales a nivel parotídeo, observándose una disminución del volumen de la glándula, acompañado de alteraciones en el adenómero y conductos estriados de la glándula, implicados en la producción, secreción y modificación de la saliva, la cual se vio alterada, en el flujo, pH, y en sus componentes.

Types I and III parotid collagen variations and serum biochemical parameters in obese rats exposed to monosodium glutamate / Variaciones de colágeno parotídeo tipos I y III y parámetros bioquímicos séricos en ratas obesas expuestas a glutamato monosódico

SUMMARY: The objective of this study was to describe the effects of monosodium glutamate on the collagen of the parotid gland in an obesity model. 18 newborn male Sprague Dawley rats were used (first control group; second group of MSG1: 4 mg/g of monosodium glutamate weight, 5 doses, and third group of MSG2: 4 mg/g of monosodium glutamate, 5 doses, maintained for 8 and 16 weeks respectively). The content and type of collagen were analyzed, in addition to the levels of cholesterol, glucose, triglycerides and uric acid. Monosodium glutamate produced an increase in the obesity rates of the MSG2 group, in addition to an increase in blood cholesterol, glucose and uric acid levels compared to the control group. Type III collagen in the MSG2 group showed a statistically significant increase. Monosodium glutamate induced obesity, in addition to an increase in type III collagen fibers.

RESUMEN: El objetivo de este estudio fue describir los efectos del glutamato monosódico sobre el colágeno de la glándula parótida en un modelo de obesidad. Se utilizaron 18 ratas Sprague Dawley machos recién nacidas (primer grupo control; segundo grupo MSG1: 4 mg/g de peso de glutamato monosódico, 5 dosis, y tercer grupo MSG2: 4 mg/g de glutamato monosódico, 5 dosis, mantenidas durante 8 y 16 semanas respectivamente). Se analizó el contenido y el tipo de colágeno, además de los niveles de colesterol, glucosa, triglicéridos y ácido úrico. El glutamato monosódico produjo un aumento en las tasas de obesidad del grupo MSG2, además de un aumento en los niveles de colesterol en sangre, glucosa y ácido úrico en comparación con el grupo control. El colágeno tipo III en el grupo MSG2 mostró un aumento estadísticamente significativo. La obesidad inducida por glutamato monosódico, además de un aumento en las fibras de colágeno tipo III.

Aislamiento e identificación de compuestos con actividad antiobesidad y antiadipogénica de Thevetia peruviana / Isolation and identification of anti-obesity and anti-adipogenic compounds from Thevetia peruviana

Thevetia peruviana ha sido utilizada en la medicina tradicional mexicana por sus efectos adelgazantes. Para la identificación de las fracciones y los compuestos activos de T. peruviana se utilizó cromatografía en columna abierta y las fracciones obtenidas se evaluaron en ratones con obesidad inducida con glutamato monosódico. Como control positivo se utilizó Orlistat y los tratamientos se administraron oralmente una vez al día durante 8 semanas. La fracción con mayor actividad fue sub-fraccionada y, con la intención de evitar el uso de más ratones, los productos fueron seleccionados por su capacidad para inhibir la adipogénesis en la línea celular 3T3-L1. Los animales tratados con la fracción F-B mostraron un aumento de peso significativamente menor y mantuvieron la sensibilidad a la insulina, así como, niveles significativamente más bajos de colesterol y triglicéridos. El análisis de GC-MS indicó que esta fracción activa está compuesta principalmente por los ácidos palmítico (1), oleico (2) y octadacanoico (3), 2-palmitoil glicerol (4), 2-oleoil glicerol (5) así como la estigmastenona (6).

Thevetia peruviana has been used in Mexican traditional medicine for its slimming effects. Active fractions and compounds from T. peruviana were isolated and identified by means of gravitational open-column chromatography, and the fractions were evaluated on mice with MonoSodium Glutamate-induced obesity. Orlistat was used as positive control, and treatments were administered, orally, once a day for 8 weeks. The fraction with higher activity was sub-fractioned and, with the intention of avoiding using more mice, the fractions were analyzed by evaluating their capability to inhibit adipogenesis in the 3T3-L1 cell line. Animals treated with the F-B fraction revealed a significantly smaller weight increase and maintained adequate insulin sensitivity, and significantly lower blood levels of cholesterol and triglycerides. The active compounds that demonstrated greatest adipogenesis inhibition were palmitic acid (1), oleic acid (2), octadecanoic acid (3), 2-palmitoyl glycerol (4), 2-oleoyl glycerol (5) and stigmastenone (6).

Suppression of monosodium glutamate-induced acute kidney injury and renal ultrastructural damage in rats by vitamin E / Supresión de lesiones renales agudas inducidas por glutamato monosódico y daño ultraestructural renal en ratas por vitamina E

Food additives and flavour enhancers used in the food industry are potential health risks. We tested the hypothesis that the food additive and flavour enhancer, monosodium glutamate (MSG), which is the sodium salt of glutamic acid can induce ultrastructural alterations to the kidney, and the antioxidant vitamin E can protect against acute kidney injuries induced by a toxic dose of MSG in a rat model of the disease. The model group of rats received a daily dose of MSG (4 gm/kg) for 7 days, whereas the protective groups were either received a 100 mg/kg vitamin E plus MSG or 300 mg/kg vitamin E plus MSG for 7 days. Rats were then sacrificed on day 8. Transmission and light microscopy images revealed substantial kidney damage induced by MSG in the model group as demonstrated by degenerated epithelial cells with Pyknotic nuclei, swollen mitochondria, damaged brush margins, dilated tubules, and widening of Bowman's space with shrinkage and deformity of some glomeruli. Treatment of the model group with vitamin E showed a substantial protection of kidney tissue and renal ultrastructure by 300 mg/kg vitamin E compared to a partial protection by 100 mg/kg vitamin E. In addition, MSG significantly (p<0.05) increased serum levels of urea and creatinine, which were significantly (p<0.05) decreased with vitamin E. However, for serum creatinine, high doses of vitamin E (300 mg/kg) were more effective than lower doses (100 mg/kg) of vitamin E. These results indicate that vitamin E at 300 mg/kg effectively protects against MSG-induced acute kidney injury in rats.

Los aditivos alimentarios y los potenciadores del sabor utilizados en la industria alimentaria son riesgos potenciales para la salud. Probamos la hipótesis de que el aditivo alimentario y el potenciador del sabor, glutamato monosódico (MSG), la sal sódica del ácido glutámico, puede inducir alteraciones ultraestructurales del riñón, y que las propiedades antioxidantes de la vitamina E, pueden proteger contra las lesiones renales inducidas por una dosis tóxica de MSG en un modelo de rata. El grupo modelo de ratas recibió una dosis diaria de MSG (4 g / kg) durante 7 días, mientras que los grupos protectores recibieron una dosis de 100 mg / kg de vitamina E más MSG o 300 mg / kg de vitamina E más MSG durante 7 días. Las ratas se sacrificaron el día 8. Las imágenes de microscopía óptica y de transmisión revelaron un daño renal sustancial inducido por el MSG en el grupo modelo, como lo demuestran las células epiteliales degeneradas con núcleos picnóticos, mitocondrias hinchadas, bordes dañados, túbulos dilatados y ensanchamiento del espacio de Bowman, además de la deformidad de algunos glomérulos. El tratamiento del grupo modelo con vitamina E mostró una protección sustancial del tejido renal y la ultraestructura renal de 300 mg / kg de vitamina E en comparación con una protección parcial de 100 mg / kg de vitamina E. Además, el MSG aumentó significativamente (p <0,05) en el suero los niveles de urea y creatinina, disminuyeron significativamente (p <0,05) con la vitamina E. Sin embargo, para la creatinina sérica, las dosis altas de vitamina E (300 mg / kg) fueron más efectivas que las dosis más bajas (100 mg / kg) de vitamina E. Estos resultados indican que la vitamina E a 300 mg / kg protege eficazmente contra la lesión renal aguda inducida por MSG en ratas.

Gosto umami: uma alternativa para a redução de sódio no preparo das refeições / Umami taste an alternative culinary tool to reduce sodium in the meal preparations

Introdução: A alimentação na atualidade está relacionada a questões de saúde pública, por ser um dos fatores que contribuem com a incidência das doenças crônicas não transmissíveis, dentre elas, a hipertensão. O consumo excessivo de sódio está associado a vários efeitos prejudiciais à saúde, como o aumento da pressão arterial e doença cardiovascular. De acordo com a Organização Mundial da Saúde (OMS), o consumo diário de sódio não deveria ultrapassar 2,0g/pessoa/dia, por causa do aumento do risco de desenvolvimento de doenças crônicas não transmissíveis. Dados da última Pesquisa de Orçamentos Familiares mostram que os brasileiros consomem, em média, 4,7g/pessoa/dia, ou seja, mais que o dobro da recomendação da OMS. Objetivo: Verificar se o gosto básico umami, na forma de glutamato monossódico monoidratado, é uma alternativa para a redução de sódio no preparo das refeições. Metodologia: Foi realizado pré-teste para definir a concentração de MSG e sal a ser utilizada nas preparações. A quantidade para o arroz com sal foi de 1,08% de adição e para o arroz com sal e MSG foi de 0,54% e 0,43% respectivamente. Para a carne com sal adicionou-se 1,10% de sal e para a carne com sal e MSG foi adicionado 0,55% e 0,44%, respectivamente. Uma amostra de arroz e de carne sem sal e sem MSG também foi preparada. Houve a apresentação a um vídeo como variável comportamental sobre adição de sal e saúde. Foi realizada análise sensorial - teste de preferência entre as 3 amostras de arroz e 3 de carne bovina - e análises físico-químicas para avaliar as quantidades de sódio e de ácido glutâmico nas amostras. A análise estatística dos resultados obtidos foi realizada por análise de variância ANOVA e teste de Friedman- valores de amplitude total estudentizada (q) /nota: nível em 5% de probabilidade. Também foram realizados cálculos dos valores de médias, desvio padrão, gráficos de distribuição, máximos e mínimos. As análises foram realizadas utilizando os softwares Microsoft Excel 2010, Stata12.0 e FizzBiosystemes®. Resultados: Participaram dos testes 103 indivíduos de ambos os gêneros, com idade entre 18 e 57 anos, sendo que 52 assistiram ao vídeo e 51 não. Os resultados demonstraram que não houve diferença significativa entre assistir ou não ao vídeo no comportamento de intenção de adição de sal às preparações pelos provadores. Os testes de preferência das preparações do arroz e da carne não apresentaram diferença significativa entre as amostras preparadas apenas com sal àquelas preparadas com sal e MSG (p>0,05). Comparando as amostras de arroz com sal e de arroz com sal e MSG o resultado obtido na análise físico química foi de 30,2% de redução de sódio. Comparando as amostras de carne com sal e de carne com sal e MSG, o resultado obtido foi de 33,12% de redução de sódio. A carne bovina contem naturalmente ácido glutâmico livre (18 mg/100g), possuindo também inosinato (80 mg/100g), o que potencializa o gosto umami naturalmente presente no alimento. Assim, por ser saborosa é possível reduzir mais o sódio quando comparada ao arroz, o qual possui naturalmente apenas 5,86mg de ácido glutâmico/100g, não apresentando quantidades significativas de inosinato. Conclusão: O MSG, que possui as propriedades gustativas do umami, pode ser um coadjuvante para reduzir a ingestão de sódio, conforme ficou evidenciado nos resultados do presente estudo

Introduction: Current nutrition is related to public health issues, since it is one of the factors that contribute to the incidence of chronic non-communicable diseases, among them, hypertension. Excessive sodium intake is associated with several detrimental health effects, such as increased blood pressure and cardiovascular disease. According to the World Health Organization (WHO), daily sodium intake should not exceed 2.0g / person / day because of the increased risk of developing non-communicable chronic diseases. Data from the last Family Budget Survey show that Brazilians consume, on average, 4.7 g / person / day, that is, more than twice the WHO recommendation. Objective: To verify if the basic taste umami, in the form of monosodium glutamate monohydrate, is efficient in reducing sodium in the meal preparations. Methodology: A pre-test was performed to define the concentration of MSG and salt to be used in the preparations. The amount of salt added in plain rice was 1.08%. For rice with salt and MSG was added 0.54% of salt and 0.43% of MSG. To prepare meat with salt, 1.10% of salt was added. To prepare meat with salt and MSG, 0.55% of salt and 0.44% of MSG were added. A sample of rice and meat without salt and no MSG was also prepared. A video about addition of salt and its impact on health was prepared as a behavioural variable. Sensory analysis - preference test between the 3 rice and 3 beef samples - and physical-chemical analyses were performed to evaluate the amounts of sodium and glutamic acid in the samples. Statistical analysis of the results was performed by analysis of variance ANOVA and Friedman test - values of total amplitude studentized (q) / note: level in 5% of probability. Were also performed calculations of averages, standard deviation, distribution and maximum and minimum values. Analyses were performed using the software Microsoft Excel 2010, Stata12.0 and FizzBiosystemes®. Results: A total of 103 individuals from both genders, aged between 18 and 57 years old, participated in the tests, 52 of them watched the video and 51 did not. The results showed that there was no significant effect of video watching on the intention of adding salt to the preparations. Preference tests for both rice and meat preparations showed no significant difference between the salt-only samples and those prepared with MSG (p> 0.05). When comparing the samples of rice with salt alone and rice with salt and MSG, the result obtained in the physical chemical analysis was 30.2% of sodium reduction. Comparing the samples of meat with salt alone and meat with salt and MSG, the result was 33.12% of sodium reduction. Beef naturally contains free glutamic acid (18 mg / 100 g) and inosinate (80 mg / 100 g), which potentiates the naturally occurring umami taste in the food. Thus, we hypothesize that because beef is umami-rich, it is possible to reduce sodium more than in rice, which naturally contains only 5.86 mg of glutamic acid / 100 g, and does not contain significant amounts of inosinate. Conclusion: MSG, which is the principal signal of umami taste, can be a cooking tool to reduce sodium intake, as evidenced in the results of the present study

Assessment of the physiological changes induced by sodium nitrite, annatto or mono sodium glutamate in male albino rats

Background: food additives are added to most junk and fast foods, especially those for kids. Sodium nitrite is an inorganic salt with widespread applications in the food industry as a color fixative and preservative in meat and fish. Annatto extract is a natural food color obtained from the outer coatings of the seeds of the Annatto tree [Bixa orellana L.]. Monosodium glutamate [MSG], the sodium salt of amino acid glutamate, is a food additive that popularly used all over the world as "flavor enhancer"

Aim of the work: this study was aimed to determine the hazardous effects of sodium nitrite, annatto and monosodium glutamate on some physiological parameters in male albino rats

Materials and methods: this study had been done on fourty male albino rats with an average body weight 100-145 g. The animals were divided into four groups; Group 1: control [untreated group], Group 2: sodium nitrite treated group, Group 3: annatto treated group and Group 4: monosodium glutamate treated group. Blood samples were collected, sera were separated and used for estimation of some biochemical parameters [liver enzymes, kidney functions, glucose, protein profile and lipid profile] and hormonal levels [testosterone, T3 [triiodothyronine] and T4 [thyroxine]]

Results: the biochemical results showed an increase in the activities of liver enzymes [aspartate aminotransferase [ASAT] and alanine aminotransferase [ALAT]], and the levels of glucose, kidney functions [urea, and creatinine], lipid profile [total cholesterol, triglycerides, low density lipoprotein [LDL-C]] and thyroid hormones [thyroxin [T4] and triiodothyronine [T3]] in all treated groups when compared to the control group. A drop in protein profile [total protein, albumin, globulin and A/G ratio], testosterone hormone and HDL level were observed in the treated groups as compared to the control rats

Conclusion: it could be concluded that some food additives like sodium nitrite, annatto, and monosodium glutamate have extreme effects on liver and kidney functions, protein and lipid profiles and also on thyroid and testosterone hormones. So, it is recommended to minimize the use of these additives to protect young children and mature people from these destructive effects

Adverse effects of two kinds of food additive mixtures [flavor enhancer, food preservative or food coloring agent] on physiological parameters in young male albino rats

Background: food additives are substances used in food industry in order to improve the food's taste, appearance by preserving its flavor and preventing it from souring. Food additives are added to the most junk and fast foods, especially food for kids

Aim of the work: this work was aimed to investigate the adverse effects of some food additives on the biochemical parameters in addition to study the side effects of these food additives in male albino rats

Materials and Methods: this study was performed on twenty four young male albino rats with an average 120-145 g body weight. Animals were divided into four groups [6 /cage]; Group I [Control untreated group], Group II [administered orally with sodium nitrite [0.1 mg/kg b.wt./day] and annatto [0.065 mg/kg b.wt./day]], Group III [administered orally with sodium nitrite [0.1 mg/kg b.wt./day] and monosodium glutamate [MSG] [15 mg/kg b.wt./day]] and Group IV [administered orally with annatto [0.065 mg/kg b.wt./day] and monosodium glutamate [15 mg/kg b.wt./day]]. Blood samples were collected on the last day of experiment, for biochemical estimations which included levels of serum glucose, total protein [TP], albumin, creatinine, urea, testosterone , thyroid hormones [T3 and T4], activities of AST and ALT in addition to lipid profile

Results: showed marked elevation in levels of fasting glucose, activities of AST, ALT, urea, creatinine, total cholesterol [TC], triglycerides [TG] and high density lipoprotein cholesterol [HDL-C], VLDL and ratios of TC/HDL-C and LDL-C/HDL-C [risk factors] as well as albumin / globulin ratio and serum thyroid hormones [T3 and T4] accompanied with marked decline in levels of serum total proteins, albumin, globulin, albumin/ creatinine ratio, testosterone and HDL-C in all treated groups in comparison to the control group. There was a significant reduction in the body weight in groups that received [NaNO2 with annatto] and [MSG with NaNO2] while treated rats with [MSG and annatto] showed a significant increase in body weight as compared to control rats

Conclusion: Due to the harmful effects of food additives, the use of these compounds must be limited as it resulted in a vehement disturbance in the biochemical and physiological parameters that was grievously pronounced on many hormones

Dietary Habits and Perception Toward Food Additives according to the Frequency of Consumption of Convenience Food at Convenience Stores among University Students in Cheongju / 대한지역사회영양학회지

OBJECTIVES: This study was performed to examine the consumption patterns of convenience food at convenience stores, dietary habits, and perception as well as knowledge of food additives among university students. METHODS: Subjects were 352 university students in Cheongju, Korea, and data was collected by a self-administered questionnaire. They were divided into three groups according to the frequency of consumption of convenience food at convenience stores: 79 rare (≤ 1 time/month), 89 moderate (2-4 times/month) and 184 frequent (≥ 2 times/week). RESULTS: More subjects from the frequent consumption group lived apart from parents (p<0.001) and possessed more pocket money (p<0.01). Frequent consumption group consumed noodles, Kimbab, and sandwich & burger significantly more often (p<0.001, respectively) than others. In addition, frequent consumption of convenience foods at convenience stores was associated with frequent breakfast skipping (p<0.05), irregular meal time (p<0.01), snacking (p<0.05), and eating late night meal (p<0.001). More from the rare consumption group had heard about food additives previously compared to the frequent consumption group (79.7% vs. 63.6%, p<0.01). Frequent consumption group showed significantly higher score than did the rare consumption group for the following questions: monosodium glutamate is harmful to your health (p<0.05), food additives are necessary for food manufacturing (p<0.005), food additives need to be labeled on products (p<0.05), there is no food additive at all if labeled as no preservatives, no coloring, and no added sugar (p<0.05). There was a significant difference in degrees of choosing products with less food additives depending on the consumption pattern. CONCLUSIONS: Our results provided a better understanding of the factors associated with frequent consumption of convenience foods at convenience stores among university students and will be useful to develop a nutrition education program for those who are more prone to consume convenience foods.

Attenuating effect of Lactobacillus brevis G101 on the MSG symptom complex in a double-blind, placebo-controlled study

BACKGROUND/OBJECTIVES: Lactobacillus brevis G101 suppresses the absorption of monosodium glutamate (MSG) from the intestine into the blood in mice. Therefore, the attenuating effect of orally administered G101 on monosodium glutamate (MSG) symptom complex was investigated in humans. MATERIALS/METHODS: Capsules (300 mg) containing Lactobacillus brevis G101 (1x1010 CFU/individual) or maltodextrin (placebo) was orally administered in 30 respondents with self-recognized monosodium glutamate (MSG) symptom complex for 5 days and the rice with black soybean sauce containing 6 g MSG (RBSM) was ingested 30 min after the final administration. Thereafter, the MSG symptom complex (rated on a 5-point scale: 1, none; 5, strong) was investigated in a double blind placebo controlled study. The intensity of the MSG symptom complex was significantly reduced in respondents of the G101 intake group (2.87 +/- 0.73) compared to that in those treated with the placebo (3.63 +/- 1.03) (P = 0.0016). Respondents in the placebo group exhibited more of the various major conditions of the MSG symptom complex than in the G101 intake group. Although there was no significant difference in the appearance time of the MSG symptom complex between subjects orally administered G101 and those administered the placebo, its disappearance in < 3 h was observed in 69.9% of subjects in the G101 treatment group and in 38.0% of subjects in the placebo group (P = 0.0841). CONCLUSIONS: Oral administration of Lactobacillus brevis G101 may be able to reduce the intensity of the MSG symptom complex.

Basophil Activation Test with Food Additives in Chronic Urticaria Patients

The role of food additives in chronic urticaria (CU) is still under investigation. In this study, we aimed to explore the association between food additives and CU by using the basophil activation test (BAT). The BAT using 15 common food additives was performed for 15 patients with CU who had a history of recurrent urticarial aggravation following intake of various foods without a definite food-specific IgE. Of the 15 patients studied, two (13.3%) showed positive BAT results for one of the tested food additives. One patient responded to monosodium glutamate, showing 18.7% of CD203c-positive basophils. Another patient showed a positive BAT result to sodium benzoate. Both patients had clinical correlations with the agents, which were partly determined by elimination diets. The present study suggested that at least a small proportion of patients with CU had symptoms associated with food additives. The results may suggest the potential utility of the BAT to identity the role of food additives in CU.

Effect of Mudan Granule on islets beta cell function in monosodium glutamate induced obese mice with insulin resistance: an experimental study / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To study the effect of Mudan Granule (MD) on the glucose metabolism and beta cell function in monosodium glutamate (MSG) induced obese mice with insulin resistance (IR).</p><p><b>METHODS</b>MSG obese mice were induced by subcutaneous injecting MSG (4 g/kg for 7 successive days in neonatal ICR mice). Forty MSG mice with IR features were recruited and divided into four groups according to body weight, fasting blood glucose, triglyceride (TG), total cholesterol (TC), and the percentage of blood glucose decreased within 40 min in the IR test, i.e., the model group (Con), the low dose MD group, the high dose MD group, and the Metformin group (Met). Besides, another 10 ICR mice were recruited as the normal control group (Nor). The water solvent of 2.5 g/kg MD or 5 g/kg MD was respectively administered to mice in the low dose MD group and the high dose MD group. Metformin hydrochloride was given to mice in the Met group at 0.2 g/kg body weight. Equal dose solvent distilled water was administered to mice in the Nor group and the Con group by gastrogavage, once per day. All medication was lasted for 15 weeks. Insulin tolerance test (ITT) and oral glucose tolerance test (OGTT) were performed after 6 weeks of treatment. Beta cell function was assessed by hyperglycemic clamp technique. The morphological changes in the pancreas were evaluated by hematoxylin-eosin (HE) staining. Changes of iNOS, NF-kappaB p65, and p-NF-kappaB p65 in the pancreas were tested.</p><p><b>RESULTS</b>Compared with the Nor group, the blood glucose level, AUC, and fasting blood insulin, ONOO-contents, iNOS activities, and the expression of iNOS, NF-kappaB p65 subunit, pNF-kappaB p65 subunit obviously increased; decreased percentage of blood glucose within 40 min in ITT, glucose infusion rate (GIR), Clamp 1 min insulin, and Max-Insulin obviously decreased in the Con group (P < 0.05, P < 0.01). Compared with the Con group, the aforesaid indices could be improved in the Met group (P < 0.05, P < 0.01). In the low dose MD group, AUC, iNOS activities, and the expression of iNOS and p-NF-kappaB p65 subunit obviously decreased; percentage of blood glucose within 40 min in ITT and GIR obviously increased (P < 0.05, P < 0.01). In the high dose MD group, AUC, ONOO-contents, iNOS activities, and the expression of iNOS, NF-kappaB p65 subunit, and p-NF-KB p65 subunit obviously decreased; percentage of blood glucose within 40 min in ITT, Max-Insulin, and GIR obviously increased (P < 0.05, P < 0.01).</p><p><b>CONCLUSION</b>MD could significantly improve IR and functional disorder of 3 cells in MSG obese mice, which might be associated with lowering inflammatory reaction in the pancreas.</p>

Caracterização dos limiares de detecção do gosto umami em crianças com e sem câncer / Characterization of umami taste sensitivity in children with and without cancer

Introdução: O gosto umami é proveniente de glutamato e 5 ribonucleotídeos, incluindo inosinato e guanilato, os quais aparecem naturalmente em muitos alimentos. Pode ser identificado pelo glutamato monossódico, sendo considerado como gosto sutil, mas misturando-se bem com outros gostos, expande e incrementa o sabor. Objetivo: Identificar os limiares de detecção do gosto umami emcrianças com Leucemia Lonfóide Aguda ou Linfoma não-Hodgkin e em escolares saudáveis, e correlacionar a sensibilidade ao gosto com o estado nutricional, idade e sexo. Método: Foi aplicado teste de sensibilidade de Threshold para determinar o limiar do gosto umami, com 6 concentrações crescentes de água deionizada e glutamato monossódico. Os indivíduos foram pesados e medidos,e calculado o IMC para determinar o estado nutricional. Para as análises estatísticas foram utilizadas versão 2.6.6 do software estatístico R e testes de Mann-Whitney e Kruskal-Wallis com níveis descritivos (p = 0,05). Resultados: a amostra foi contituida de 102 pacientes e 42 escolares, sendo que 74 do sexo masculino (53,9 por cento e 54,8 por cento), 93 eutróficos (63,7 por cento e 69,0 por cento) e 43 na faixa etária de 6 a 9 anos (58,8 por cento e 52,4 por cento), respectivamente. A maioria dos pacientes (92,0 por cento) e escolares (97,4 por cento) eram sensíveis ao gosto umami e tiveram valores de limiar de sensibilidade semelhantes ao gosto umami. Não foi encontrada diferença estatisticamente significante entre os limiares do gosto umami de pacientes sensíveis e escolares, IMC, sexo. Conclusões: a percepção ao gosto umami foi independente do sexo, idade, estado nutricional ou presença de doença.

INTRODUCTION: The umami taste comes from glutamate and 5 ribonucleotides including inosinate and guanylate, which appear naturally in many foods. It can be identified by monosodium glutamate, being considered as a subtle taste, but blending well with other tastes, expands and enhances the flavor. OBJECTIVE: to identify umami taste thresholds in children with ALL or NHL and in healthy school children and to correlate taste sensitivity with nutritional status, age and gender. METHODS: The threshold sensitivity test was applied to determine umami taste using 6 solutions containing increasing concentrations of deionized water and monosodium glutamate. Subjects were weighed and measured, and BMI was calculated to determine nutritional status. For statistical analyses were used version 2.6.6 of the R Statistical software and Mann-Whitney and Kruskal-Wallis tests with descriptive levels (p = 0.05). RESULTS: The sample consisted of 102 patients and 42 school children, and that subjects were male (53.9% and 54.8%), eutrophic (63.7% and 69.0%) and aged from 6 to 9 years (58.8% and 52.4%), respectively. Most patients (92.0%) and school children (97.4%) were sensitive to umami taste and had similar umami taste threshold values. No statistically significant difference was found between umami taste thresholds of sensitive patients and school children, BMI, gender. CONCLUSIONS: Perception of umami taste was independent of gender, age, nutritional status or presence of disease.

A preliminary experimental study on the cardiac toxicity of glutamate and the role of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Monosodium L-glutamate (MSG) is a food flavour enhancer and its potential harmfulness to the heart remains controversial. We investigated whether MSG could induce cardiac arrhythmias and apoptosis via the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor.</p><p><b>METHODS</b>Myocardial infarction (MI) was created by ligating the coronary artery and ventricular arrhythmias were monitored by electrocardiogram in the rat in vivo. Neonatal rat cardiomyocytes were isolated and cultured. Cell viability was estimated by 3-(4,5)-dimethylthiahiazo(-z-yl)-3,5-di-phenytetrazoliumromide (MTT) assay. Calcium mobilization was monitored by confocal microscopy. Cardiomyocyte apoptosis was evaluated by acridine orange staining, flow cytometry, DNA laddering, reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.</p><p><b>RESULTS</b>MSG (i.v.) decreased the heart rate at 0.5 g/kg and serious bradycardia at 1.5 g/kg, but could not induce ventricular tachyarrhythmias in normal rats in vivo. In rats with acute MI in vivo, however, MSG (1.5 g/kg, i.v.) induced ventricular tachyarrhythmias and these arrhythmias could be prevented by blocking the AMPA and N-methyl-d-aspartate (NMDA) receptors. Selectively activating the AMPA or NMDA receptor induced ventricular tachyarrhythmias in MI rats. At the cellular level, AMPA induced calcium mobilization, oxidative stress, mitochondrial dysfunction and apoptosis in cultured cardiomyocytes, especially when the AMPA receptor desensitization were blocked by cyclothiazide. The above toxic cellular effects of AMPA were abolished by AMPA receptor blockade or by H2O2 scavengers.</p><p><b>CONCLUSIONS</b>MSG induces bradycardia in normal rats, but triggers lethal tachyarrhythmias in myocardial infarcted rats probably by hindering AMPA receptors. AMPA receptor overstimulation also induces cardiomyocyte apoptosis, which may facilitate arrhythmia.</p>