Characterization of macrophage phenotype, redox, and purinergic response upon chronic treatment with methionine and methionine sulfoxide in mice.

Hypermethioninemia is a disorder characterized by high plasma levels of methionine (Met) and its metabolites such as methionine sulfoxide (MetO). Studies have reported associated inflammatory complications, but the mechanisms involved in the pathophysiology of hypermethioninemia are still uncertain. The present study aims to evaluate the effect of chronic administration of Met and/or MetO on phenotypic characteristics of macrophages, in addition to oxidative stress, purinergic system, and inflammatory mediators in macrophages. In this study, Swiss male mice were subcutaneously injected with Met and MetO at concentrations of 0.35-1.2 g/kg body weight and 0.09-0.3 g/kg body weight, respectively, from the 10th-38th day post-birth, while the control group was treated with saline solution. The results revealed that Met and/or MetO induce an M1/classical activation phenotype associated with increased levels of tumor necrosis factor alpha and nitrite, and reduced arginase activity. It was also found that Met and/or MetO alter the activity of antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase, as well as the levels of thiol and reactive oxygen species in macrophages. The chronic administration of Met and/or MetO also promotes alteration in the hydrolysis of ATP and ADP, as indicated by the increased activity of ectonucleotidases. These results demonstrate that chronic administration of Met and/or MetO promotes activated pro-inflammatory profile by inducing M1/classical macrophage polarization. Thus, the changes in redox status and purinergic system upon chronic Met and/or MetO exposure may contribute towards better understanding of the alterations consistent with hypermethioninemic patients.

2-(2-Methoxyphenyl)-3-((Piperidin-1-yl)ethyl)thiazolidin-4-One-Loaded Polymeric Nanocapsules: In Vitro Antiglioma Activity and In Vivo Toxicity Evaluation.

Among gliomas types, glioblastoma is considered the most malignant and the worst form of primary brain tumor. It is characterized by high infiltration rate and great angiogenic capacity. The presence of an inflammatory microenvironment contributes to chemo/radioresistance, resulting in poor prognosis for patients. Recent data show that thiazolidinones have a wide range of pharmacological properties, including anti-inflammatory and antiglioma activities. Nanocapsules of biodegradable polymers become an alternative to cancer treatment since they provide targeted drug delivery and could overcome blood-brain barrier. Therefore, here we investigated the in vitro antiglioma activity and the potential in vivo toxicity of 2- (2-methoxyphenyl) -3- ((piperidin-1-yl) ethyl) thiazolidin-4-one-loaded polymeric nanocapsules (4L-N). Nanocapsules were prepared and characterized in terms of particle size, polydispersity index, zeta potential, pH, molecule content and encapsulation efficiency. Treatment with 4L-N selectively decreased human U138MG and rat C6 cell lines viability and proliferation, being even more efficient than the free-form molecule (4L). In addition, 4L-N did not promote toxicity to primary astrocytes. We further demonstrated that the treatment with sub-therapeutic dose of 4L-N did not alter weight, neither resulted in mortality, toxicity or peripheral damage to Wistar rats. Finally, 4L as well as 4L-N did not alter makers of oxidative damage, such as TBARS levels and total sulfhydryl content, and did not change antioxidant enzymes SOD and CAT activity in liver and brain of treated rats. Taken together, these data indicate that the nanoencapsulation of 4L has potentiated its antiglioma effect and does not cause in vivo toxicity.

Methionine and methionine sulfoxide treatment induces M1/classical macrophage polarization and modulates oxidative stress and purinergic signaling parameters.

Methionine is an essential amino acid involved in critical metabolic process, and regulation of methionine flux through metabolism is important to supply this amino acid for cell needs. Elevation in plasma methionine commonly occurs due to mutations in methionine-metabolizing enzymes, such as methionine adenosyltransferase. Hypermethioninemic patients exhibit clinical manifestations, including neuronal and liver disorders involving inflammation and tissue injury, which pathophysiology is not completely established. Here, we hypothesize that alterations in macrophage inflammatory response may contribute to deleterious effects of hypermethioninemia. To this end, macrophage primary cultures were exposed to methionine (1 mM) and/or its metabolite methionine sulfoxide (0.5 mM), and M1/proinflammatory or M2/anti-inflammatory macrophage polarization was evaluated. In addition, inflammation-related pathways including oxidative stress parameters, as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities; reactive oxygen species (ROS) production, and purinergic signaling, as ATP/ADP/AMPase activities, were investigated. Methionine and/or methionine sulfoxide induced M1/classical macrophage activation, which is related to proinflammatory responses characterized by increased iNOS activity and TNF-α release. Further experiments showed that treatments promoted alterations on redox state of macrophages by differentially modulated SOD and CAT activities and ROS levels. Finally, methionine and/or methionine sulfoxide treatment also altered the extracellular nucleotide metabolism, promoting an increase of ATPase/ADPase activities in macrophages. In conclusion, these findings contribute to better understand the participation of proinflammatory responses in cell injury observed in hypermethioninemic patients.

Glioma sensitive or chemoresistant to temozolomide differentially modulate macrophage protumor activities.

BACKGROUND: Glioblastomas are the most devastating brain tumor characterized by chemoresistance development and poor prognosis. Macrophages are a component of tumor microenvironment related to glioma malignancy. The relation among inflammation, innate immunity and cancer is accepted; however, molecular and cellular mechanisms mediating this relation and chemoresistance remain unresolved. OBJECTIVE: Here we evaluated whether glioma sensitive or resistant to temozolomide (TMZ) modulate macrophage polarization and inflammatory pathways associated. The impact of glioma-macrophage crosstalk on glioma proliferation was also investigated. METHODS: GL261 glioma chemoresistance was developed by exposing cells to increasing TMZ concentrations over a period of 6months. Mouse peritoneal macrophages were exposed to glioma-conditioned medium or co-cultured directly with glioma sensitive (GL) or chemoresistant (GLTMZ). Macrophage polarization, in vitro and in vivo glioma proliferation, redox parameters, ectonucleotidase activity and ATP cytotoxicity were performed. RESULTS: GLTMZ cells were more effective than GL in induce M2-like macrophage polarization and in promote a strong immunosuppressive environment characterized by high IL-10 release and increased antioxidant potential, which may contribute to glioma chemoresistance and proliferation. Interestingly, macrophage-GLTMZ crosstalk enhanced in vitro and in vivo proliferation of chemoresistant cells, decreased ectonucleotidase activities, which was followed by increased macrophage sensitivity to ATP induced death. CONCLUSIONS: Results suggest a differential macrophage modulation by GLTMZ cells, which may favor the maintenance of immunosuppressive tumor microenvironment and glioma proliferation. GENERAL SIGNIFICANCE: The induction of immunosuppressive environment and macrophage education by chemoresistant gliomas may be important for tumor recovery after chemotherapy and could be considered to overcome chemoresistance development.

Preventive Effect of Cecropia pachystachya Against Ketamine-Induced Manic Behavior and Oxidative Stress in Rats.

Cecropia species are widely used in traditional medicine by its anti-diabetic, anti-hypertensive and anti-inflammatory properties. In the present study, we investigated the neuroprotective and antioxidant effects of the crude aqueous extract from Cecropia pachystachya leaves in a rat model of mania induced by ketamine. The results indicated that ketamine treatment (25 mg/kg i.p., for 8 days) induced hyperlocomotion in the open-field test and oxidative damage in prefrontal cortex and hippocampus, evaluated by increased lipid peroxidation, carbonyl protein formation and decreased total thiol content. Moreover, ketamine treatment reduced the activity of the antioxidant enzymes superoxide dismutase and catalase in hippocampus. Pretreatment of rats with C. pachystachya aqueous extract (200 and 400 mg/kg p.o., for 14 days) or with lithium chloride (45 mg/kg p.o., for 14 days, used as a positive control) prevented both behavioral and pro-oxidant effects of ketamine. These findings suggest that C. pachystachya might be a useful tool for preventive intervention in bipolar disorder, reducing the episode relapse and the oxidative damage associated with the manic phase of this disorder .

Synthesis and antioxidant activity of 3-(Pyridin-2-ylmethyl)-1,3-thiazinan(thiazolidin)-4-ones.

The antioxidant properties of two series of thiazolidinones and thiazinanones were reported. The novel six-membered thiazinanones were synthesized from the efficient multicomponent reaction of 2-picolylamine (2-aminomethylpyridine), arenaldehydes, and the 3-mercaptopropionic acid in moderate to excellent yields. These novel compounds were fully identified and characterized by NMR and GC-MS techniques. In vitro antioxidant activities of all compounds were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) tests. The antioxidant assays of thiobarbituric acid reactive species and total thiol content levels in the cerebral cortex and liver of rats were also performed. Thiazinanone 5a showed the best radical scavenging activity in DPPH and ABTS tests, as well as reduced lipid peroxidation and increased total thiol group in biological systems. Altogether, the results may be considered a good starting point for the discovery of a new radical scavenger.

Efficient synthesis and antioxidant evaluation of 2-aryl-3-(pyrimidin-2-yl)-thiazolidinones.

In the present study, we reported the efficient synthesis of 11 3-(pyrimidin-2-yl)-thiazolidinones in good yields using molecular sieve as the desiccant agent. In addition, we have evaluated the antioxidant capacity of the synthesized compounds by the 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH•) and the 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS(+•) ) radicals scavenging assay. Six compounds showed antioxidant activity towards DPPH• (EC50 between 16.13 and 49.94 µg/mL) and also demonstrated excellent activity regarding ABTS(+•) (TEAC: 10.32-53.52). These results showed that compounds 3-(pyrimidin-2-yl)-thiazolidinones may be easily synthesized by a less expensive procedure and could be a good starting point to the development of new antioxidant compounds.

Antioxidant capacity and environmentally friendly synthesis of dihydropyrimidin-(2H)-ones promoted by naturally occurring organic acids.

The Biginelli reaction is a multicomponent reaction involving the condensation between an aldehyde, a ß-ketoester, and urea or thiourea, in the presence of an acid catalyst, producing dihydropyrimidinones (DHPMs). Owing to their important pharmacological properties, the DHPMs have been studied by many authors. However, most of the methodologies used for the synthesis of these compounds require drastic reaction conditions. In the current study, we report an efficient and clean procedure for preparing DHPMs by the use of citric acid or tartaric acid as a promoter of the Biginelli synthesis in ethanol as solvent. In addition, we have evaluated the antioxidant capacity of the compounds synthesized by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay and the thiobarbituric acid-reactive species test. Two compounds presented antioxidant activity and also reduced lipid peroxidation at concentrations of 200 and 300 µM. In summary, we report an environmentally friendly procedure for the preparation of DHPMs and demonstrate the antioxidant capacity of some of the compounds.

Effects of tannic acid in streptozotocin-induced sporadic Alzheimer's Disease: insights into memory, redox status, Na+, K+-ATPase and acetylcholinesterase activity.

The aim of this study was to investigate the ability of tannic acid (TA) in preventing memory deficits and neurochemical alterations observed in a model for Sporadic Dementia of Alzheimer's Type. Rats were treated with TA (30 mg/kg) daily for 21 days, and subsequently received intracerebroventricular injection of streptozotocin (STZ). We observed that STZ induced learning and memory impairments; however, treatment with TA was able to prevent these effects. In cerebral cortex and hippocampus, STZ induced an increase in acetylcholinesterase activity, reduced Na+, K+-ATPase activity and induced oxidative stress increasing thiobarbituric acid-reactive substances, nitrites and reactive oxygen species levels and reducing the activity of antioxidant enzymes. Treatment with TA was able in prevent the major of these neurochemical alterations. In conclusion, TA prevented memory deficits, alterations in brain enzyme activities, and oxidative damage induced by STZ. Thus, TA can be an interesting strategy in the prevention of Sporadic Alzheimer's Disease.

Role of antioxidants on Na(+),K (+)-ATPase activity and gene expression in cerebral cortex of hyperprolinemic rats.

Considering that Na(+),K(+)-ATPase is an embedded-membrane enzyme and that experimental chronic hyperprolinemia decreases the activity of this enzyme in brain synaptic plasma membranes, the present study investigated the effect of chronic proline administration on thiobarbituric acid-reactive substances, as well as the influence of antioxidant vitamins E plus C on the effects mediated by proline on Na(+),K(+)-ATPase activity in cerebral cortex of rats. The expression of Na(+),K(+)-ATPase catalytic subunits was also evaluated. Results showed that proline increased thiobarbituric acid-reactive substances, suggesting an increase of lipid peroxidation. Furthermore, concomitant administration of vitamins E plus C significantly prevented the increase of lipid peroxidation, as well as the inhibition of Na(+),K(+)-ATPase activity caused by proline. We did not observe any change in levels of Na(+),K(+)-ATPase mRNA transcripts after chronic exposure to proline and vitamins E plus C. These findings provide insights into the mechanisms through which proline exerts its effects on brain function and suggest that treatment with antioxidants may be beneficial to treat neurological dysfunctions present in hyperprolinemic patients.

Blackberry extract improves behavioral and neurochemical dysfunctions in a ketamine-induced rat model of mania.

Bipolar disorder is a chronic mood disorder characterized by episodes of mania and depression. The aim of this study was to investigate the effects of blackberry extract on behavioral parameters, oxidative stress and inflammatory markers in a ketamine-induced model of mania. Animals were pretreated with extract (200 mg/kg, once a day for 14 days), lithium chloride (45 mg/kg, twice a day for 14 days), or vehicle. Between the 8th and 14th days, the animals received an injection of ketamine (25 mg/kg) or vehicle. On the 15th day, thirty minutes after ketamine administration, the animals' locomotion was assessed using open-field apparatus. After the experiments, the animals were euthanized and cerebral structures were removed for neurochemical analyses. The results showed that ketamine treatment induced hyperlocomotion and oxidative damage in the cerebral cortex, hippocampus and striatum. In contrast, pretreatment with the extract or lithium was able to prevent hyperlocomotion and oxidative damage in the cerebral cortex, hippocampus, and striatum. In addition, IL-6 and IL-10 levels were increased by ketamine, while the extract prevented these effects in the cerebral cortex. Pretreatment with the extract was also effective in decreasing IL-6 and increasing the level of IL-10 in the striatum. In summary, our findings suggest that blackberry consumption could help prevent or reduce manic episodes, since this extract have demonstrated neuroprotective properties as well as antioxidant and anti-inflammatory effects in the ketamine-induced mania model.

Tannic Acid Ameliorates STZ-Induced Alzheimer's Disease-Like Impairment of Memory, Neuroinflammation, Neuronal Death and Modulates Akt Expression.

Tannic acid (TA) is a hydrolysable glycosidic polyphenol polymer of gallic acid, which possesses neuroprotective properties. The aim of this study was to evaluate the effect of TA treatment on cognitive performance and neurochemical changes in an experimental model of sporadic dementia of Alzheimer's type (SDAT) induced by intracerebroventricular (ICV) injection of streptozotocin (STZ) and to explore the potential cellular and molecular mechanisms underlying these effects. Adult male rats were divided into four groups: control, TA, STZ, and TA + STZ. Animals from TA and TA + STZ groups were treated with TA (30 mg/kg) daily, by gavage, for 21 days; others groups received water (1 mL/kg). Subsequently, an ICV injection of STZ (3 mg/kg) was administered into the lateral ventricles of animals from STZ and TA + STZ groups, while other groups received citrate buffer. Cognitive deficits (short-term memory), neuronal survival, neuroinflammation as well as expression of SNAP-25, Akt, and pAkt were evaluated in the cerebral cortex. TA treatment protected against the impairment of memory in STZ-induced SDAT. STZ promoted an increase in neuronal death and the levels of proinflammatory cytokines (IL-6 and TNF-α) and a decrease in Akt and pAkt expression; TA was able to restore these changes. Neither STZ nor TA altered SNAP-25 expression or the levels of IL-12 and IL-4 in the cerebral cortex. Our study highlights that treatment with TA prevents memory deficits and reestablishes Akt and pAkt expression, protecting against neuronal death and neuroinflammation in STZ-induced SDAT in rats.

Chronic hyperhomocysteinemia alters antioxidant defenses and increases DNA damage in brain and blood of rats: protective effect of folic acid.

We have previously demonstrated that acute hyperhomocysteinemia induces oxidative stress in rat brain. In the present study, we initially investigated the effect of chronic hyperhomocysteinemia on some parameters of oxidative damage, namely total radical-trapping antioxidant potential and activities of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase), as well as on DNA damage in parietal cortex and blood of rats. We also evaluated the effect of folic acid on biochemical alterations elicited by hyperhomocysteinemia. Wistar rats received daily subcutaneous injection of Hcy (0.3-0.6 micromol/g body weight), and/or folic acid (0.011 micromol/g body weight) from their 6th to their 28th day of life. Twelve hours after the last injection the rats were sacrificed, parietal cortex and total blood was collected. Results showed that chronic homocysteine administration increased DNA damage, evaluated by comet assay, and disrupted antioxidant defenses (enzymatic and non-enzymatic) in parietal cortex and blood/plasma. Folic acid concurrent administration prevented homocysteine effects, possibly by its antioxidant and DNA stability maintenance properties. If confirmed in human beings, our results could propose that the supplementation of folic acid can be used as an adjuvant therapy in disorders that accumulate homocysteine.

Guanidinoacetate decreases antioxidant defenses and total protein sulfhydryl content in striatum of rats.

Guanidinoacetate methyltransferase (GAMT) deficiency is an inherited neurometabolic disorder biochemically characterized by tissue accumulation of guanidinoacetate (GAA) and depletion of creatine. Affected patients present epilepsy and mental retardation whose pathogeny is unclear. In the present study we investigated the in vitro and in vivo (intrastriatal administration) effects of GAA on some oxidative stress parameters in rat striatum. Sixty-day-old rats were used for intrastriatal infusion of GAA. For the in vitro studies, 60-day-old Wistar rats were killed by decapitation and the striatum was pre-incubated for 1 h at 37 degrees C in the presence of GAA at final concentrations ranging from 10 to 100 microM. Parameters of oxidative stress such as total radical-trapping antioxidant potential (TRAP), antioxidant enzymes (SOD, GPx, and CAT), protein carbonyl and thiol contents were measured. DNA damage was also evaluated. Results showed that GAA administration (in vivo studies) or the addition of 100 microM GAA to assays (in vitro studies) significantly decreased TRAP, SOD activity, and total thiol levels in rat striatum. In contrast, this guanidino compound did not alter protein carbonyl content and the activities of CAT and GPx. DNA damage was not found after intrastriatal administration of GAA. The data indicate that the metabolite accumulating in GAMT deficiency decreases antioxidant capacity and total thiol content in the striatum. It is therefore presumed that this pathomechanism may contribute at least in part to the pathophysiology of the brain injury observed in patients affected by GAMT deficiency.

Effects of chronic proline administration on lipid contents of rat brain.

In the present work we investigated the effects of chronic proline administration on ganglioside, cholesterol and phospholipid total contents, as well as on ganglioside profile in cerebral cortex, hippocampus, hypothalamus and cerebellum of rats. We also evaluated the ganglioside content and profile in detergent-soluble and resistant microdomains isolated from synaptic membranes obtained from cerebral cortex. Proline solution (hyperprolinemic) or saline (control) were subcutaneously administered to rats from 6th to 28th post-natal day, according to body weight. Twelve hours after the last injection, the animals were sacrificed by decapitation without anaesthesia. Brain structures were homogenized with chloroform:methanol for lipid extraction. Synaptic membranes were obtained by differential centrifugation and detergent-soluble and resistant microdomains were isolated by cold Triton X-100 treatment. Results showed that rats subjected to chronic proline treatment presented a significant increase of ganglioside content in cortex and hippocampus, while this membrane lipid content was not altered in hypothalamus and cerebellum. Besides, phospholipid and cholesterol contents were not modified in all structures studied. On the other hand, ganglioside content decreased in detergent-soluble and resistant microdomains isolated from synaptic membrane obtained from hyperprolinemic cortex. Although ganglioside profiles were apparently not modified, the individual absolute quantities were altered in cortex and hippocampus total lipid extract and membrane microdomains. Our findings suggest that chronic proline treatment affects in a distinct manner different cerebral regions concerning the lipid composition of the cell membranes, reflecting on its distribution in the cortex membrane microdomains. Among these phenomena consequences, distinct modulations in synaptic transmission may be suggested which might contribute to the impairment in cognition and/or other neurological dysfunctions found in hyperprolinemia type II patients.

Chemically induced model of hypermethioninemia in rats.

In the present study, we developed a chronic chemically induced model of hypermethioninemia in rats. We induced elevated concentrations of methionine in the blood by injecting subcutaneously methionine (1.34-2.68 micromol/g of body weight) to developing animals of various ages. Brain methionine concentrations were approximately 1.25 micromol/g wet tissue ( approximately 1.0mM). We then injected the same doses of methionine to young rats twice a day at 8h intervals from the 6(th) to the 28(th) postpartum day. Controls received saline in the same volumes. The body, brain and hippocampus of rats were weighed after treatment and showed that hypermethioninemic animals had no differences in these parameters, when compared to the control group, suggesting that methionine did not cause malnutrition in the rats. Considering that experimental animal models are useful to understand the pathophysiology of human disease, the present model of hypermethioninemia may contribute to the investigation of the mechanisms of brain damage caused by high tissue methionine levels.

Homocysteine reduces cholinesterase activity in rat and human serum.

In the present study we investigated the effect of homocysteine administration, the main metabolite accumulating in homocystinuria, on cholinesterase activity in rat and human serum. For the in vivo study, 8-, 15- and 60-day-old rats received one subcutaneous injection of homocysteine (0.3, 0.4 or 0.6 micromol/g of body weight, respectively) or saline (control) and were sacrificed 1h later, when serum was collected in order to determine cholinesterase activity. For the in vitro studies, serum of 8-, 15- and 60-day-old untreated rats or 20-25- and 52-60-day-old human beings (healthy volunteers) were incubated with 10-500 microM homocysteine. Results showed that acute hyperhomocysteinemia (in vivo study) significantly reduced cholinesterase activity in the serum of rats of all ages tested. We also observed that 500 microM homocysteine added to the incubation medium (in vitro study) significantly inhibited cholinesterase activity both in serum of rats and humans. Our findings seem to reinforce the proposed associations of cholinesterase activity with hyperhomocysteinemia.

Concurrent folate treatment prevents Na+,K+-ATPase activity inhibition and memory impairments caused by chronic hyperhomocysteinemia during rat development.

We investigated the hypothesis that folate administration would prevent hyperhomocysteinemia-induced memory deficits and Na(+),K(+)-ATPase activity inhibition. Chronic hyperhomocysteinemia was induced from the 6th to the 28th day of life by subcutaneous injection of homocysteine (0.3-0.6 micromol/g), twice a day; control Wistar rats received the same volume of saline solution (0.9% NaCl). Half of the homocysteine- and saline-treated groups also received intraperitoneal administration of folate (0.011 micromol/g) from the 6th to the 28th day of life. A group of animals was killed 12 h after the last injection, plasma and parietal cortex were collected for biochemical analysis. Another group stayed at Central Animal House until 60th day of life, when the rats were submitted to behavioral testing in water maze or were killed for evaluation of cortical Na(+),K(+)-ATPase activity. Results showed that hyperhomocysteinemia impaired reference memory for platform location, as assessed by fewer crossings to the platform place and increased latency for the first crossing, when compared to controls. In the working memory task homocysteine-treated animals also needed more time to find the platform. We also observed that Na(+),K(+)-ATPase activity was reduced in parietal cortex of hyperhomocysteinemic rats sacrificed 12h after the last injection of homocysteine (29-day-old rats). In contrast, this enzyme was not altered when the rats were sacrificed 31 days after the treatment (60-day-old rats). Hyperhomocysteinemic rats treated with folate had all those impairments prevented, an effect probably related to folate antioxidant properties.

Reduction of gangliosides, phospholipids and cholesterol content in cerebral cortex of rats caused by chronic hypermethioninemia.

Neurological dysfunction is observed in patients with severe hypermethioninemia, whose physiopathology is still poorly understood. In the current study we investigated the effect of chronic administration of methionine on the content and species of gangliosides and phospholipids, as well as on the concentration of cholesterol in rat cerebral cortex. Wistar rats received subcutaneous injections of methionine (1.34-2.68 micromol/g of body weight), twice a day, from the 6th to the 28th day of age and controls received saline. Animals were killed 12h after the last injection. Results showed that methionine administration significantly decreased the total content of lipids in cerebral cortex of rats. We also observed that this amino acid significantly reduced the absolute quantity of the major brain gangliosides (GM1, GD1a, GD1b and GT1b) and phospholipids (sphingomyelin, phosphatidylcholine and phosphatidylethanolamine). We also showed that Na+,K+-ATPase activity and TBARS were changed in cerebral cortex of rats subjected to hypermethioninemia. If confirmed in human beings, these data could suggest that the alteration in lipid composition, Na+,K+-ATPase activity and TBARS caused by methionine might contribute to the neurophysiopathology observed in hypermethioninemic patients.

Synthetic 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones exhibit selective in vitro antitumoral activity and inhibit cancer cell growth in a preclinical model of glioblastoma multiforme.

Glioblastoma multiforme (GBM) is the worst form of primary brain tumor, which has a high rate of infiltration and resistance to radiation and chemotherapy, resulting in poor prognosis for patients. Recent studies show that thiazolidinones have a wide range of pharmacological properties including antimicrobial, anti-inflammatory, anti-oxidant and anti-tumor. Here, we investigate the effect antiglioma in vitro of a panel of sixteen synthetic 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones where 13 of these decreased the viability of glioma cells 30-65% (100 µM) compared with controls. The most promising compounds such as 4d, 4l, 4m and 4p promoted glioma reduction of viability greater than 50%, were further tested at lower concentrations (12.5, 25, 50 and 100 µM). Also, the data showed that the compounds 4d, 4l, 4m and 4p induced cell death primarily through necrosis and late apoptosis mechanisms. Interestingly, none of these 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones were cytotoxic for primary astrocytes, which were used as a non-transformed cell model, indicating selectivity. Our results also show that the treatment with sub-therapeutic doses of 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones (4d, 4l and 4p) reduced in vivo glioma growth as well as malignant characteristics of implanted tumors such as intratumoral hemorrhage and peripheral pseudopalisading. Importantly, 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones treatment did not induce mortality or peripheral damage to animals. Finally, 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones also changed the nitric oxide metabolism which may be associated with reduced growth and malignity characteristics of gliomas. These data indicates for the first time the therapeutic potential of synthetic 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones to GBM treatment.