Methotrexate-induced subacute myelopathy: a serious but treatable complication.

Subacute myelopathy is a rare but serious complication of methotrexate (MTX) that may cause paraplegia. Although its underlying mechanisms have not been fully elucidated, homocysteine is thought to play a role in the pathogenesis of this adverse effect. Herein, we report the case of a 34-years old female patient with diffuse large B-cell lymphoma who developed progressive paraplegia accompanied by dysfunctional bladder and bowel movements after treatment with a modified CODOX-M/IVAC regimen, including high-dose intravenous MTX and intrathecal (IT-) MTX. Neurological symptoms gradually improved to almost normal levels within 4.5 months of onset following treatment with a combination of S-adenosylmethionine, methionine, cyanocobalamin, and folate. During chemotherapy, including high-dose MTX and IT-MTX for hematological malignancies, MTX-induced subacute neuronal damage should be carefully evaluated, and appropriate treatment should be initiated as early as possible.

Dietary Methionine Supplementation Exacerbates Gastrointestinal Toxicity in a Mouse Model of Abdominal Irradiation.

BACKGROUND AND PURPOSE: Identification of appropriate dietary strategies for prevention of weight and muscle loss in cancer patients is crucial for successful treatment and prolonged patient survival. High-protein oral nutritional supplements decrease mortality and improve indices of nutritional status in cancer patients; however, high-protein diets are often rich in methionine, and experimental evidence indicates that a methionine-supplemented diet (MSD) exacerbates gastrointestinal toxicity after total body irradiation. Here, we sought to investigate whether MSD can exacerbate gastrointestinal toxicity after local abdominal irradiation, an exposure regimen more relevant to clinical settings. MATERIALS AND METHODS: Male CBA/CaJ mice fed either a methionine-adequate diet or MSD (6.5 mg methionine/kg diet vs 19.5 mg/kg) received localized abdominal X-irradiation (220 kV, 13 mA) using the Small Animal Radiation Research Platform, and tissues were harvested 4, 7, and 10 days after irradiation. RESULTS: MSD exacerbated gastrointestinal toxicity after local abdominal irradiation with 12.5 Gy. This was evident as impaired nutrient absorption was paralleled by reduced body weight recovery. Mechanistically, significant shifts in the gut ecology, evident as decreased microbiome diversity, and substantially increased bacterial species that belong to the genus Bacteroides triggered proinflammatory responses. The latter were evident as increases in circulating neutrophils with corresponding decreases in lymphocytes and associated molecular alterations, exhibited as increases in mRNA levels of proinflammatory genes Icam1, Casp1, Cd14, and Myd88. Altered expression of the tight junction-related proteins Cldn2, Cldn5, and Cldn6 indicated a possible increase in intestinal permeability and bacterial translocation to the liver. CONCLUSIONS: We report that dietary supplementation with methionine exacerbates gastrointestinal syndrome in locally irradiated mice. This study demonstrates the important roles registered dieticians should play in clinical oncology and further underlines the necessity of preclinical and clinical investigations in the role of diet in the success of cancer therapy.

Proposals for Upper Limits of Safe Intake for Methionine, Histidine, and Lysine in Healthy Humans.

Based on research presented during the 10th Amino Acid Assessment Workshop, no observed adverse effect levels (NOAELs) for supplemental methionine at 46 mg/(kg·d) (∼3.2 g/d), for supplemental histidine at 8.0 g/d, and for supplemental lysine at 6.0 g/d have been proposed. These NOAELs are relevant to healthy adults and are applicable only to high-purity amino acids administered in fortified foods or dietary supplements. Because individuals are exposed to the above supplemental amino acids in the context of complex combinations of essential amino acids or individually in dietary supplements for various physiologic benefits, such as body fat reduction, skin conditioning, mental energy increase, or herpes simplex treatments, the above safety recommendations will make an important contribution to regulatory and nutritional practices.

Metabolic Consequences of Supplemented Methionine in a Clinical Context.

The central position of methionine (Met) in protein metabolism indicates the importance of this essential amino acid for growth and maintenance of lean body mass. Therefore, Met might be a tempting candidate for supplementation. However, because Met is also the precursor of homocysteine (Hcy), a deficient intake of B vitamins or excessive intake of Met may result in hyperhomocysteinemia (HHcy), which is a risk factor for cardiovascular disease. This review discusses the evidence generated in preclinical and clinical studies on the importance and potentially harmful effects of Met supplementation and elaborates on potential clinical applications of supplemental Met with reference to clinical studies performed over the past 20 y. Recently acquired knowledge about the NOAEL (no observed adverse effect level) of 46.3 mg · kg-1 · d-1 and the LOAEL (lowest observed adverse effect level) of 91 mg · kg-1 · d-1 of supplemented Met will guide the design of future studies to further establish the role of Met as a potential (safe) candidate for nutritional supplementation in clinical applications.

L-Methionine associated with Hibiscus sabdariffa and Boswellia serrata extracts are not inferior to antibiotic treatment for symptoms relief in patients affected by recurrent uncomplicated urinary tract infections: Focus on antibiotic-sparing approach.

OBJECTIVE: To evaluate the efficacy of a phytotherapic combination of L-Methionine associated with Hibiscus sabdariffa and Boswellia serrata for treatment of acute episodes of uncomplicated urinary tract infections (UTI) in women affected by recurrent UTIs. MATERIALS AND METHODS: In this randomized phase III clinical trial, adult females with uncomplicated UTI were enrolled into one of the following treatment groups: Group A: phytotherapic combination 1 tablet in the morning and 1 tablet in the evening for 7 days; Group B: Short term antibiotic treatment according to international guidelines recommendations. At baseline, all patients were evaluated by a urologist and quality of life (QoL) questionnaires and mid-stream urine culture. Same clinical and laboratory investigations were repeated at each follow-up visit. RESULTS: Forty-six patients were enrolled in Group A and 47 in Group B. At the first follow-up (30 days), both groups showed a statistically significant improvement in quality of life scores as compared with baseline assessment [Group A: (QoL 94.3 VS 98.5 p < 0.001); Group B: (QoL 94.5 VS 98.7 p < 0.001)]. An improvement from baseline was also seen at the second followup evaluation after 3 months [Group A: (QoL 94.3 VS 99.1 p < 0.001); Group B: (QoL 94.5 VS 98.1 p < 0.001)]. At the second follow-up visit, a statistically significant difference in QoL was reported between the two groups (99.1 VS 98.1; p < 0.003) and a transition from UTI to asymptomatic bacteriuria (ABU) was observed 12 of 46 (26%) patients in Group A, while no patients in Group B demonstrated ABU (p = 0.007). CONCLUSIONS: Here, we demonstrated that this phytotherapic combination is able, in comparison to antibiotic treatment, to improve patients quality of life, reducing symptoms in acute setting and preventing the recurrences. Interestingly, a significantly higher proportion of patients in the phytotherapy group had ABU after three months. Our findings are of great interest in an antibiotic stewardship perspective.

Subchronic methionine load induces oxidative stress and provokes biochemical and histological changes in the rat liver tissue.

The aim of this study was to assess the effects of L-cysteine (Cys) (7 mg/kg) and N-acetyl-L-cysteine (NAC) (50 mg/kg) in the rat liver caused by subchronic i.p. application of methionine (Met) (0.8 mmol/kg) during 21 days. Malondialdehyde (MDA) concentration, glutathione content (GSH), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and acetylcholinesterase (AchE) activities were determined in the liver tissue and activities of liver enzymes (AST, ALT, ALP, and GGT) and concentrations of total proteins and albumin were determinated in plasma/serum. Catalase, superoxide dismutase, and acetylcholinesterase activities were increased by Cys and NAC. Met caused periportal mononuclear infiltration and rare focal necrosis of hepatocytes. In Cys- and NAC-supplemented groups, intracellular edema and microvesicular fatty changes without necrosis were noticed. We observed decrease of AST, ALT, and ALP activity in the methionine-treated group. Our results indicate that Cys and NAC application can increase activity of antioxidative enzymes and prevent intensive histological changes in liver in condition of subchronic methionine exposure.

Tolerance to increased supplemented dietary intakes of methionine in healthy older adults.

Background: l-Methionine (Met) is an essential amino acid for humans and is important for protein synthesis and the formation of polyamines and is involved in the synthesis of many metabolites, including homocysteine. Free-Met supplements have been claimed to have multiple positive effects; however, it remains unclear what the exact tolerance level is. With aging, Met metabolism changes, and increased plasma homocysteine is more apparent. High plasma concentrations of homocysteine are assumed to be associated with a high risk of developing atherosclerosis.Objective: We estimated the no-observed-adverse-effect level (NOAEL) and the lowest-observed-adverse-effect level (LOAEL) of supplemented, oral, free Met in healthy older adults by examining the increase in plasma homocysteine as the primary determinant.Design: We provided capsules with free Met to 15 healthy older adult subjects for 4 wk at climbing dosages of, on average, 9.2, 22.5, 46.3 and 91 mg · kg body weight-1 · d-1 with washout periods of 2 wk between each intake. Before, at 2 and 4 wk during, and 2 wk after each dosage, we studied a complete panel of biochemical blood variables to detect possible intolerance to increased Met intake. Plasma homocysteine and body composition were measured, and tolerance, quality of life, and cognitive function were assessed via questionnaires.Results: Plasma homocysteine was elevated with the highest dose of supplemented Met. The estimated NOAEL of supplemented Met was set at 46.3 mg · kg body weight-1 · d-1, and the estimated LOAEL of supplemented Met was set at 91 mg · kg body weight-1 · d-1 (on the basis of the actual intakes) in subjects independent of sex. No signs of intolerance were observed via questionnaires or other blood variables at the LOAEL. There were no meaningful changes in body composition.Conclusions: On the basis of plasma homocysteine, the NOAEL of supplemented Met intake is 46.3 and the LOAEL is 91 mg · kg body weight-1 · d-1 in healthy older adults. Both the NOAEL and LOAEL are not associated with meaningful effects on health and wellbeing. This trial was registered at clinicaltrials.gov as NCT02566434.

Selenium Inhibits Homocysteine-Induced Endothelial Dysfunction and Apoptosis via Activation of AKT.

BACKGROUND/AIMS: Endothelial cells are crucial in vascular homeostasis. Dysfunction of endothelial cells is involved in the development of cardiovascular diseases (CVD). High plasma homocysteine (Hcy) correlates with CVD while selenium supplementation counteracts development of CVD. However, the underlying mechanism remained unclear. Here, we investigated the effects of selenium on homocysteine-induced endothelial dysfunction. METHODS: An animal model of Hcy-induced endothelial dysfunction was established by intragastric administration of L-methionine. Plasma NO and von Willebrand factor (vWF) were quantified using NO assay and ELISA kit respectively. Relaxation was measured in thoracic aortic ring assays. Cell viability and migration were detected by Cell Counting Kit-8 and Bio-Coat cell migration chambers respectively. Cellular apoptosis was determined by Annexin V-FITC apoptosis kit. RESULTS: Selenium prevented homocysteine-induced endothelial injury and impairment of endothelium-dependent relaxation. Selenium reversed the impaired viability and migration of endothelial cells induced by homocysteine in a dose-dependent manner. Selenium inhibited the apoptosis of endothelial cells induced by homocysteine, through downregulating of Caspase-3 activity and expression of Caspase-3 and Bax, and by stimulating Bcl-2 expression. Selenium reversed the homocysteine-induced reduction of NO release, and increased the expression and phosphoylation of endothelial nitric oxide synthetase (eNOS) in a dose-dependent manner. Moreover, selenium enhanced AKT phosphorylation, and selenium-induced phosphorylation and expression of eNOS were inhibited by AKT inhibition. NO production, cell viability and migration rescued by selenium were inhibited, while cell apoptosis was reversed by AKT inhibition. CONCLUSION: Selenium protected against homocysteine-induced dysfunction and apoptosis of endothelial cells through AKT pathway. The observations may provide novel therapeutic opportunities in the treatment of CVD.

6-gingerol protects against nutritional steatohepatitis by regulating key genes related to inflammation and lipid metabolism.

Non-alcoholic fatty liver disease, including non-alcoholic steatohepatitis (NASH), appears to be increasingly common worldwide. The aim of the study was to investigate the effects of 6-gingerol ((S)-5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-3-decanone), a bioactive ingredient of plants belonging to the Zingiberaceae family, on experimental models of NASH. In HepG2 cells, 6-gingerol (100 µmol/L) treatment inhibited free fatty acids mixture (0.33 mmol/L palmitate and 0.66 mmol/L oleate)-induced triglyceride and inflammatory marker accumulations. Male C57BL/6 mice were fed with a methionine and choline-deficient (MCD) diet to induce steatohepatitis. After four weeks of MCD diet feeding, the mice were dosed orally with 6-gingerol (25, 50 or 100 mg/kg/day) once daily for another four weeks. 6-Gingerol (100 mg/kg/day) attenuated liver steatosis and necro-inflammation in MCD diet-fed mice. The expressions of inflammatory cytokine genes, including those for monocyte chemoattractant protein-1, tumor necrosis factor-α, and interleukin-6, and nuclear transcription factor (NF-κB), which were increased in the livers of MCD diet-fed mice, were attenuated by 6-gingerol. 6-Gingerol possesses a repressive property on hepatic steatosis, which is associated with induction of peroxisome proliferator-activated receptor α. Our study demonstrated the protective role of 6-gingerol in ameliorating nutritional steatohepatitis. The effect was mediated through regulating key genes related to lipid metabolism and inflammation.

Whey protein supplementation increases methionine intake but not homocysteine plasma concentration in rats.

The purpose of this study was to examine the effects of whey protein supplementation on homocysteine (Hcy) metabolism and liver oxidative stress in rats. Twenty-four rats were divided into 3 groups (n = 8) to receive one of the following diets for 4 weeks: control diet (C), whey protein-composed diet (WP), and whey protein-supplemented diet (WPS). The C and WP diets consisted of AIN-93 with 20% casein and 20% whey protein as protein source, respectively. WPS was AIN-93 (20% casein) supplemented by the addition of 20% (w/w) whey protein. Four weeks of ingesting a WPS diet resulted in a significantly higher (P < 0.05) total protein and methionine intakes. Although a significant increase (P < 0.05) in the hepatic S-adenosylmethionine and S-adenosylhomocysteine levels occurred in WPS group compared with C and WP, no significant change was observed in plasma Hcy concentration between groups. Furthermore, the levels of lipid hydroperoxides and advanced oxidation protein products, known liver oxidative stress markers, were increased in the WPS group compared with the C group. In addition, no change in glutathione liver concentration was observed in any of the groups studied. In conclusion, whey protein supplementation increases methionine intake substantially; however, it does not change plasma Hcy concentrations. On the other hand, increased hepatic oxidative stress markers were observed in whey protein supplemented rats were probably due to high protein intake.

The effects of α-lipoic acid on liver oxidative stress and free fatty acid composition in methionine-choline deficient diet-induced NAFLD.

Development of nonalcoholic fatty liver disease (NAFLD) occurs through initial steatosis and subsequent oxidative stress. The aim of this study was to examine the effects of α-lipoic acid (LA) on methionine-choline deficient (MCD) diet-induced NAFLD in mice. Male C57BL/6 mice (n=21) were divided into three groups (n=7 per group): (1) control fed with standard chow, (2) MCD2 group--fed with MCD diet for 2 weeks, and (3) MCD2+LA group--2 weeks on MCD receiving LA i.p. 100 mg/kg/day. After the treatment, liver samples were taken for pathohistology, oxidative stress parameters, antioxidative enzymes, and liver free fatty acid (FFA) composition. Mild microvesicular hepatic steatosis was found in MCD2 group, while it was reduced to single fat droplets evident in MCD2+LA group. Lipid peroxidation and nitrosative stress were increased by MCD diet, while LA administration induced a decrease in liver malondialdehyde and nitrates+nitrites level. Similary, LA improved liver antioxidative capacity by increasing total superoxide dismutase (tSOD), manganese SOD (MnSOD), and copper/zinc-SOD (Cu/ZnSOD) activity as well as glutathione (GSH) content. Liver FFA profile has shown a significant decrease in saturated acids, arachidonic, and docosahexaenoic acid (DHA), while LA treatment increased their proportions. It can be concluded that LA ameliorates lipid peroxidation and nitrosative stress in MCD diet-induced hepatic steatosis through an increase in SOD activity and GSH level. In addition, LA increases the proportion of palmitic, stearic, arachidonic, and DHA in the fatty liver. An increase in DHA may be a potential mechanism of anti-inflammatory and antioxidant effects of LA in MCD diet-induced NAFLD.

Insulin autoimmune syndrome in a health supplement user: the effectiveness of cornstarch therapy for treating hypoglycemia.

A 70-year-old woman with no history of diabetes was admitted to the hospital for the management of hypoglycemia. Her fasting plasma glucose level was 54 mg/dL with an extremely high serum immunoreactive insulin level (1210 µU/mL). She had high titers of anti-insulin antibodies and exhibited the DRB1*0406 genotype for HLA-DR4, leading to a diagnosis of insulin autoimmune syndrome. She had been taking several health preparations for approximately 10 years; however, all were thiol group-free. Due to frequent episodes of nocturnal hypoglycemia, the health preparations were discontinued and the patient was treated with cornstarch. This protocol successfully ameliorated the hypoglycemic episodes and normalized the patient's laboratory and serological test results.

Effect of catechin/epicatechin dietary intake on endothelial dysfunction biomarkers and proinflammatory cytokines in aorta of hyperhomocysteinemic mice.

PURPOSE: Hyperhomocysteinemia is well recognized as an independent risk factor for the development of premature atherosclerosis. Atherosclerosis, however, may be prevented by polyphenols, potent antioxidant compounds with anti-atherogenic properties. Previously, we used cystathionine beta synthase-deficient mice [Cbs (±)] fed a high-methionine diet-a murine model of hyperhomocysteinemia-to show that daily intake of a red wine polyphenolic extract, mainly comprised of catechin and epicatechin, has a beneficial effect on aortic expression of endothelial dysfunction biomarkers and pro-inflammatory cytokines. The aim of the present study was to understand whether catechin and epicatechin, in purified forms, have anti-atherogenic effects in hyperhomocysteinemia. METHODS: Cbs (±) mice received 50 µg of catechin and/or epicatechin daily in drinking water for 1 month. Plasma homocysteine (Hcy) level and aortic expression of several endothelial dysfunction biomarkers (Vcam-1, Icam-1, E-selectin, and Lox-1) and pro-inflammatory cytokines (Tnf-α, Il-6) were assessed. RESULTS: We found that both catechin and epicatechin had a beneficial effect on plasma homocysteine levels and endothelial dysfunction biomarker expression; however, only catechin had a beneficial effect on pro-inflammatory cytokine expression. Further, when both polyphenols were given, a beneficial effect was observed only on pro-inflammatory cytokine expression. CONCLUSIONS: Catechin seems to be a more potent anti-atherogenic compound than epicatechin in hyperhomocysteinemia and should be considered as a novel therapeutic approach against endothelial dysfunction induced by this condition.

Palm tocotrienol-rich fraction reduced plasma homocysteine and heart oxidative stress in rats fed with a high-methionine diet.

Oxidative stress contributes to cardiovascular diseases. We aimed to study the effects of palm tocotrienol-rich fraction (TRF) on plasma homocysteine and cardiac oxidative stress in rats fed with a high-methionine diet. Forty-two male Wistar rats were divided into six groups. The first group was the control. Groups 2-6 were fed 1% methionine diet for 10 weeks. From week 6 onward, folate (8 mg/kg diet) or palm TRF (30, 60 and 150 mg/kg diet) was added into the diet of groups 3, 4, 5 and 6. The rats were then killed. Palm TRF at 150 mg/kg and folate supplementation prevented the increase in plasma total homocysteine (4.14 ± 0.33 and 4.30 ± 0.26 vs 5.49 ± 0.25 mmol/L, p < 0.05) induced by a high-methionine diet. The increased heart thiobarbituric acid reactive substance in rats fed with high-methionine diet was also prevented by the supplementations of palm TRF (60 and 150 mg/kg) and folate. The high-methionine group had a lower glutathione peroxidase activity (49 ± 3 vs 69 ± 4 pmol/mg protein/min) than the control group. This reduction was reversed by palm TRF at 60 and 150 mg/kg diet (p < 0.05), but not by folate. Catalase and superoxide dismutase activities were unaffected by both methionine and vitamin supplementations. In conclusion, palm TRF was comparable to folate in reducing high-methionine diet-induced hyperhomocysteinemia and oxidative stress in the rats' hearts. However, palm TRF was more effective than folate in preserving the heart glutathione peroxidase enzyme activity.

Dandelion leaf extract protects against liver injury induced by methionine- and choline-deficient diet in mice.

We investigated the hepatoprotective effects of the extract of dandelion leaves (EDL) on a murine model of methionine- and choline-deficient (MCD) diet-induced nonalcoholic steatohepatitis (NASH). C57BL/6 mice were fed for 4 weeks with one of the following diets: control diet (Cont), MCD diet (MCD), MCD diet supplemented with EDL at 200 mg/kg body weight·daily (MCD+D200), and MCD diet supplemented with EDL at 500 mg/kg body weight·daily (MCD+D500). Hepatic function was assessed by evaluating the following parameters: liver histology; plasma levels of alanine aminotransferase (ALT), triglyceride (TG), malondialdehyde (MDA), and reduced glutathione (GSH); expression levels of TNF-α and IL-6; and levels of caspase-3 and pJNK/JNK protein. Histopathological evaluations revealed that addition of EDL to the MCD diet dampens the severity of the clinical signs of NASH. Moreover, EDL led to a significant decrease in the serum levels of ALT, hepatic TG, and MDA, and in the expression levels of TNF-α, and IL-6; on the contrary, the levels of reduced GSH increased. At the post-transcriptional level, EDL significantly decreased the activation of procaspase-3 to active caspase-3, and the phosphorylation of JNK. These results suggest that the beneficial effects of EDL on NASH are mainly due to its antioxidant and anti-inflammatory activities.

Prophylaxis of recurrent urinary tract infection after renal transplantation by cranberry juice and L-methionine.

BACKGROUND: Recurrent urinary tract infections (UTIs) increase mortality and reduce graft survival after renal transplantation. Strategies to prevent recurrent UTIs include L-methionine, cranberry juice, and antibiotics. Data on the efficacy of cranberry and L-methionine, however, are controversial in the general population; there are few data in renal transplant recipients. METHODS: We performed a retrospective analysis of 82 transplant recipients with recurrent UTIs, who underwent prophylaxis with cranberry juice (2 × 50 mL/d, n = 39, 47.6%), or L-methionine (3 × 500 mg/d, n = 25, 30.5%), or both modalities (n = 18, 21.9%). Thirty patients without prophylaxis served as controls. We analyzed symptoms, pyuria/nitrituria, and incidence of UTI events during 1 year before versus after initiation of prophylaxis. RESULTS: Prophylaxis highly significantly decreased the annual UTI incidence by 58.3% (P < .001) in the study population with no change in the control group (P = .85); in addition, 53.7% of symptomatic patients reported relief of symptoms and pyuria/nitrituria disappeared in 42.4% of the dipstick-positive patients (P < .001 each). Cranberry reduced the annual number of UTI episodes by 63.9% from 3.6 ± 1.4 to 1.3 ± 1.3/year (P < .001) and L-methionine by 48.7% from 3.9 ± 1.8 to 2.0 ± 1.3/year (P < .001). CONCLUSION: Cranberry juice and L-methionine successfully reduced the incidence of UTI after renal transplantation.

Effect of excessive methionine on the development of the cranial growth plate in newborn rats.

OBJECTIVE: Methionine is an essential amino acid and pivotal for normal growth and development. However, previous animal studies have shown that excessive maternal intake of methionine causes growth restrictions, organ damages, and abnormal growth of the mandible in newborn animals. However, the effect of excessive methionine on the development of the cranial growth plate is unknown. This study investigated histological alterations of the cranial growth plate induced by high methionine administration in newborn rats. DESIGN: Twenty pregnant dams were divided into a control and an experimental group. The controls received a diet for rats and the experimental group was fed from the 18th gestational day with a special manufactured high methionine diet for rats. The high methionine diet was maintained until the end of the lactation phase (day 20). The offspring of both groups were killed at day 10 or 20 postnatally and their spheno-occipital synchondroses were collected for histological analysis. RESULTS: The weight of the high-dose methionine treated experimental group was considerably reduced in comparison to the control group at day 10 and 20 postnatally. The cartilaginous area of the growth plate and the height of the proliferative zone were markedly reduced at postnatal day 10 in the experimental group. CONCLUSIONS: In summary, the diet-induced hypermethioninemia in rat dams resulted in growth retardations and histomorphological changes of the spheno-occipital synchondrosis, an important craniofacial growth centre in newborns. This finding may elucidate facial dysmorphoses reported in patients suffering from hypermethioninemia.

The effect of dietary methionine and white tea on oxidative status of gilthead sea bream (Sparus aurata).

Free radicals are continuously generated during an organism's lifetime. In order to understand the involvement in the oxidative status of fish, methionine and white tea were assayed as antioxidant supplements in diets for gilthead sea bream (Sparus aurata). For the purpose of this study, four isonitrogenous and isolipidic diets were formulated to contain 45 % of protein and 18 % lipid and 0·3 % methionine (Met diet), 2·9 % white tea dry leaves (Tea diet) and 2·9 % of white tea dry leaves + 0·3 % methionine (Tea + Met diet). An unsupplemented diet was used as the control. Key enzymatic antioxidant defences, superoxide dismutase (SOD) isoenzyme profile, total, reduced and oxidised glutathione and oxidative damage markers were determined. The results showed that dietary methionine supplementation increased liver SOD activity, while white tea induced higher hepatic catalase activity. Dietary white tea induced a notable increase in Mn-SOD isoenzyme. This is the first study to provide evidence that dietary tea inclusion in fish feeding could be an important source of Mn with metabolic repercussions on antioxidant mechanisms.

[The effects of tea polyphenols on the injury of fibrinolytic functions induced by high-methionine dietary in rats].

OBJECTIVE: To study the protective impact of tea polyphenols (TP) on the injury of fibrinolytic functions induced by high-methionine dietary in rats. METHODS: 50 male Wistar rats were divided by stratified based on body weight into 5 groups with 10 in each group: namely control group, model group, low-dose TP group, medium-dose TP group and high-dose TP group. The rats in model group and TP groups were fed with 3% methionine dietary, control group rats with routine diet. In addition, rats in low-dose, medium-dose and high-dose TP groups were treated with TP at 50, 100 and 200 mg/kg dosage respectively by gavages every day, control group and model group rats were given with same amount distilled water. The animals were sacrificed after 8 weeks. The levels of tissue-type plasminogen activator (t-PA) and type-1 plasminogen activator inhibitor (PAI-1) in plasma were determined by ELISA assays, mRNA levels of t-PA and PAI-1 in aortic arch were detected by RT-PCR, t-PA and PAI-1 expression in aortic arch were detected by immunohistochemistry strept-avidin-biotin complex (SABC). RESULTS: After experiment, the t-PA expression of aortic arch in control group, model group, low-dose TP group, medium-dose TP group and high-dose TP group were 133.03 ± 10.14, 95.46 ± 11.08, 111.97 ± 11.91, 130.23 ± 10.80, 139.39 ± 9.41 (F = 14.15, P < 0.01), respectively, and the PAI-1 expression were 90.91 ± 8.67, 166.76 ± 12.18, 139.63 ± 12.71, 134.66 ± 13.19, 109.49 ± 10.82 (F = 31.44, P < 0.01). The t-PA concentration of plasma were (10.69 ± 1.26), (6.13 ± 0.92), (8.56 ± 1.19), (9.69 ± 0.92), (11.97 ± 1.08) ng/ml, respectively (F = 41.98, P < 0.01), and the PAI-1 concentration of plasma were (6.31 ± 0.81), (16.98 ± 1.27), (11.39 ± 0.82), (8.46 ± 0.67), (8.08 ± 0.91) ng/ml, respectively (F = 207.74, P < 0.01). The mRNA levels of t-PA in aortic arch were 1.12 ± 0.02, 0.75 ± 0.14, 1.01 ± 0.09, 0.95 ± 0.08, 1.05 ± 0.13 (F = 5.77, P < 0.05), and the mRNA levels of PAI-1 in aortic arch were 1.25 ± 0.11, 1.74 ± 0.06, 1.23 ± 0.05, 1.09 ± 0.14, 1.23 ± 0.04 (F = 23.56, P < 0.01). CONCLUSION: The results indicate that TP seems to have regulatory function on transcription and protein levels of t-PA and PAI-1, in addition to maintaining the balance between PAI-1 and t-PA and healing the injury of fibrinolytic functions in rats induced by high-methionine dietary.

[Effects of tea polyphenols on the activity of GSH-Px and NOS, and the content of MDA and NO in rats fed with high methionine diet].

OBJECTIVE: To study the effect of tea polyphenols (TP) on the content of malondialdehyde (MDA) and nitric oxide (NO) and the activity of GSH-Px and nitric oxide synthase (NOS) in rats fed with high methionine diet. METHODS: Wistar rats were randomly divided into 5 groups: model group, control group and 3 TP groups. Rats in model group and TP groups were fed with 3% methionine in diet, and rats in control group with routine diet. Rats in low-, midium- and high-dose TP groups were treated with 50, 100 and 200 mg/kg TP respectively by gavage every day for 8 weeks. Rats in control group and model group were given equal volume of distilled water. Activities of GSH-Px and NOS and contents of NO and MDA in serum were detected. Histopathological changes of aortic arc were observed by hematoxylin-eosin (HE) staining techniques. RESULTS: There were no statistically significant changes of GSH-Px activities among all groups. Compared with model group, MDA contents decreased by 27.1% in low-dose TP group (P < 0.01). Activities of NOS in TP groups increased respectively by 18.7%, 15.1% and 18.0% (P < 0.01), and NO contents in low- and high-dose TP groups increased by 113.4% and 73.4% (P < 0.01), respectively. A proliferation of vascular smooth muscle cells (VSMC) and increased thickness of aortic arch was observed in rats of model group, and these changes were suppressed in TP groups. CONCLUSION: Lipid peroxidation induced by high-methionine diet could be protected by TP. The function of endothelial cells could be maintained by increasing the NOS activity and NO contents, thus the injury of endothelial cells induced by high-methionine diet could be prevented and reduced by TP.