Alterations of the glutamatergic system in diabetes mellitus.

Diabetes mellitus (DM) is a chronic disease characterized by elevated blood glucose levels caused by a lack of insulin production (type 1 diabetes) or insulin resistance (type 2 diabetes). It is well known that DM is associated with cognitive deficits and metabolic and neurophysiological changes in the brain. Glutamate is the main excitatory neurotransmitter in the central nervous system that plays a key role in synaptic plasticity, learning, and memory processes. An increasing number of studies have suggested that abnormal activity of the glutamatergic system is implicated in the pathophysiology of DM. Dysfunction of glutamatergic neurotransmission in the central nervous system can provide an important neurobiological substrate for many disorders. Magnetic resonance spectroscopy (MRS) is a non-invasive technique that allows a better understanding of the central nervous system factors by measuring in vivo the concentrations of brain metabolites within the area of interest. Here, we briefly review the MRS studies that have examined glutamate levels in the brain of patients with DM. The present article also summarizes the available data on abnormalities in glutamatergic neurotransmission observed in different animal models of DM. In addition, the role of gut microbiota in the development of glutamatergic alterations in DM is addressed. We speculate that therapeutic strategies targeting the glutamatergic system may be beneficial in the treatment of central nervous system-related changes in diabetic patients.

The Anticonvulsant Effect of a Novel Indole-Related Compound in the Kainate-Induced Status Epilepticus in Mice: The Role of the Antioxidant and Anti-inflammatory Mechanism.

We synthesized a series of novel indole compounds containing aroylhydrazone moieties and evaluated them in mice to check their anticonvulsant activity. In the present study the most potent C3-modified derivative 3e, containing 2-furyl fragment was evaluated in kainate (KA)-induced status epilepticus (SE) and the consequences on oxidative stress and inflammation in the hippocampus in mice were explored. Melatonin was used as positive control while the melatonin receptor antagonist Luzindol was studied alone or in combination with melatonin or 3e, respectively. After intraperitoneal (i.p.) pre-treatment with melatonin 3e, Luzindol + melatonin and Luzindol + 3e for 7 days (melatonin and 3e-30 mg kg-1 or 60 mg kg-1, Luzindol 10 mg kg-1) the animals were i.p. injected with KA (30 mg kg-1, i.p.). The 3e decreased the SE-induced seizure intensity while melatonin suppressed seizures at the higher dose of 60 mg kg-1. Luzindol blocked the anticonvulsant effect of both Mel and 3e. The dose-dependent antioxidant effect of 3e measured by reduced glutathione (GSH) and total GSH in the hippocampus, was comparable to the effect of melatonin. Luzindol fully blocked the effect of melatonin but affected partially the antioxidant activity of 3e. The KA-induced increased amplifier of neuroinflammation high-mobility group box protein 1 (HMGB1) was neither alleviated by melatonin, nor by 3e. The activation by this DNA-binding protein receptor for advanced glycation end products (RAGE) was not affected by SE, melatonin and 3e pre-treatment. Our results suggest that the novel indole derivate 3e, containing 2-furyl fragment, might be clinically useful as an adjunct therapy against SE and concomitant oxidative stress.

Effect of a Ketogenic Diet on Oxidative Posttranslational Protein Modifications and Brain Homogenate Denaturation in the Kindling Model of Epilepsy in Mice.

This study focused on the ketogenic diet (KD) effects on oxidative posttranslational protein modification (PPM) as presumptive factors implicated in epileptogenesis. A 28-day of KD treatment was performed. The corneal kindling model of epileptogenesis was used. Four groups of adult male ICR mice (25-30 g) were randomized in standard rodent chow (SRC) group, KD-treatment group; SRC + kindling group; KD + kindling group (n = 10 each). Advanced oxidation protein products (AOPP) and protein carbonyl contents of brain homogenates together with differential scanning calorimetry (DSC) were evaluated. Two exothermic transitions (Exo1 and Exo2) were explored after deconvolution of the thermograms. Factor analysis was applied. The protective effect of KD in the kindling model was demonstrated with both decreased seizure score and increased seizure latency. KD significantly decreased glucose and increased ketone bodies (KB) in blood. Despite its antiseizure effect, the KD increased the AOPP level and the brain proteome's exothermic transitions, suggestive for qualitative modifications. The ratio of the two exothermic peaks (Exo2/Exo1) of the thermograms from the KD vs. SRC treated group differed more than twice (3.7 vs. 1.6). Kindling introduced the opposite effect, changing this ratio to 2.7 for the KD + kindling group. Kindling significantly increased glucose and KB in the blood whereas decreased the BW under the SRC treatment. Kindling decreased carbonyl proteins in the brain irrespectively of the diet. Further evaluations are needed to assess the nature of correspondence of calorimetric images of the brain homogenates with PPM.

Evaluation of neurobiological and antioxidant effects of novel melatonin analogs in mice.

Based on the pharmacophore model of melatonin (MT1) receptor, we recently synthesized a series of indole derivatives that showed anticonvulsant activity with low neurotoxicity and hepatotoxicity in rodents. In the present study, the three most potent C3-modified derivatives with hydrazine structure 3c, 3e, and 3f, with 2-chlorophenyl, 2-furyl, and 2-thienyl fragments, respectively, were selected, and their neurobiological activity was explored in mice. In Experiment #1, the dose-dependent anxiolytic effect of a single i.p. administration of the novel compounds at doses of 10, 30, and 60 mg/kg were studied in the open field (OF) test. In Experiment#2, the analgesic effect of 3c, 3e, and 3f (30-100 mg/kg) was tested in the hot plate test and formalin test. Experiment#3 was designed to assess the antidepressant-like activity of 3c, 3e, and 3f (10-60 mg/kg). The forced swimming test (FST) and tail suspension test (TST)-induced effect on markers of oxidative stress in the frontal cortex (FC), and the hippocampus was evaluated. Melatonin was used in the same doses as melatonin analogs in all three experiments as a positive control. Desipramine (10 mg/kg) was also applied as a control in the FST. The three melatonin analogs bearing hydrazide/hydrazone substitution at 3C of the indol scaffold demonstrated improved antidepressant-like activity compared to the melatonin. The tested substances are devoided of anxiolytic effects. The antioxidant activity of the melatonin analogs and analgesic potential is comparable to that of melatonin. The 3C substitution with hydrazide/hydrazone moiety substantially contributes to the antidepressant and antioxidant activity of the melatonin analogs.

Discovery of novel indole-based aroylhydrazones as anticonvulsants: Pharmacophore-based design.

A number of novel melatonin derivatives, containing aroylhydrazone moieties, were synthesized and explored in vivo for anticonvulsant activity, neurotoxicity in ICR mice as well as in-vitro for cytoxicity and oxidative stress in rats. The structures and configurations were confirmed by NMR, FTIR, HRMS and crystal X-ray diffraction method. For selection of potent structures for synthesis a pharmacophore model was used. Two compounds 3e, with a 2-furyl moiety fragment and 3f with 2-thienyl fragment, showed a potency in maximal electroshock (MES) test (ED50 = 50.98 mg kg-1, PI > 5.88 and ED50 = 108.7 mg kg-1; PI > 2.76), respectively, higher than melatonin (ED50 = 160.3 mg kg-1, PI > 1.87). The compounds 3c, 3e, 3f and 3i suppressed psychomotor seizures in the 6 Hz test and 3c was the most potent with higher ED50 = 13.98 mg kg-1 and PI of > 21.46 compared to that of melatonin (ED50 = 49.76 mg kg-1 and PI of > 6.03) in mice. None of the compounds displayed neurotoxicity in the rota-rod test. The novel melatonin derivatives exerted weak cytotoxic effects while 3f showed the lowest hepatoxic effects comparable to that of the positive control melatonin in rats. The high affinities to the elucidated pharmacophore model of the novel melatonin compounds derived from the inclusion of aroylhydrazone moiety in the indole scaffold yielded suitable candidates with anticonvulsant activity in the MES and 6 Hz test of psychomotor seizures.

Recent Developments of Hydrazide/Hydrazone Derivatives and Their Analogs as Anticonvulsant Agents in Animal Models.

Preclinical Research Epilepsy is a chronic devastating neurological disorder characterized by synchronous interictal discharges. Treatment with antiepileptic drugs (AEDs) can alleviate spontaneous seizure activity without preventing the progression and development of epileptogenesis. Current design and development of new AEDs and strategies for the prevention of epilepsy is focused mainly on attenuating uncontrolled seizures, severe side effects and toxicity in chronic drug therapy. It has thus become necessary to discover new chemical pharmacophores with a broad spectrum of activity and less neurotoxicity. Hydrazide/hydrazone derivatives that possess a -CO-NHN=CH- group constitute an important class of compounds for drug development. This review highlights the specific characteristics of various hydrazide/hydrazone derivatives and structurally related semicarbazones, semicarbazides and Schiff base compounds and their anticonvulsant activities. It is focused on the influence of differently substituted pharmacophores developed through SAR studies and testing their activity against different pharmcological targets. Drug Dev Res 77 : 379-392, 2016. © 2016 Wiley Periodicals, Inc.

Therapeutic potential of orally applied KB-R7943 in streptozotocin-induced neuropathy in rats.

Both peripheral neuropathy and depression can be viewed as neurodegeneration's consequences of diabetes, at least in part coexisting with or resulting from sodium-calcium dysbalance. This study aims to assess the therapeutic potential of the orally applied reverse-mode inhibitor of the sodium-calcium exchanger (NCX) KB-R7943 in the streptozotocin (STZ) diabetes model in rats. A pilot pharmacokinetic (PK) study with high-performance liquid chromatography with high-resolution tandem mass spectrometric detection revealed higher drug exposure (AUC), lower volume of distribution (Vd) and clearance (Cl), and faster decline of the plasma concentration (ƛ) in rats with diabetes vs. controls. Brain and heart accumulation and urinary excretion of the unmetabolized KB-R7943 at least 24 h were also demonstrated in all rats. However, heart and hippocampus KB-R7943 penetration (AUCtissue/AUCplasma) was higher in controls vs. diabetic rats. The development of thermal, mechanical, and chemical-induced allodynia was assessed with the Cold plate test (CPT), Randall-Stiletto (R-S) test, and 0.5% formalin test (FT). Amitriptyline 10 mg/kg, KB-R7943 5 mg/kg, or 10 mg/kg p.o once daily was applied from the 28th to the 49th day. The body weight, coat status, CPT, R-S, and FT were evaluated on days (-5), 0, and 42. On day 41, a forced swim test and 24-h spontaneous physical activities were assessed. The chronic treatment effects were calculated as % of the maximum. A dose-depended amelioration of neuropathic and depression-like effects was demonstrated. The oral application of KB-R7943 for potentially treating neurodegenerative consequences of diabetes merits further studies. The brain, heart, and kidneys are essential contributors to the PKs of this drug, and their safety involvement needs to be further characterized.

Graves' disease: pathophysiological aspects and considerations about using the chemometric analysis in the study of the disease.

Graves' disease is an immune system disorder that results in the overproduction of thyroid hormones (hyperthyroidism). Thyroid disorders are a societal problem of great public concern because of their high prevalence. This problem can affect the well-being and quality of life of patients. The predisposing factors leading to this disease are not yet fully established and are likely to be interconnected in a complex way. Chemometric analysis allows for the detection of specific relationships between the medical parameter measurements obtained from the patients in an observation group, and the identification of patterns of similarity between these patients. It is not commonly used in clinical trials; however, it can provide reliable information which may help in creating more successful, individualised treatment strategies for established groups (patterns) of patients.The aim of this review is to summarize the latest knowledge about the risk factors for Graves' disease and considerations about using the chemometric analysis in the study of the disease.

Type 2 diabetes mellitus and cardiovascular risk; what the pharmacotherapy can change through the epigenetics.

Diabetes mellitus and cardiovascular diseases are part of the metabolic syndrome and share similar risk factors, including obesity, arterial hypertension, and dyslipidemia. Atherosclerosis and insulin resistance contribute to the development of the diseases, and subclinical inflammation is observed in both conditions. There are many proofs about the connection between epigenetic factors and different diseases, including diabetes and cardiovascular diseases. Interestingly, recent studies show that at least some anti-diabetic drugs, as well as blockers of the renin-angiotensin-aldosterone system (RAAS), exert epigenetic effects aside from their hypoglycemic and antihypertensive functions, respectively. More studies are needed to discover other positive effects of the medications established through epigenetic mechanisms and to find out more about the epigenetic role in the development of diabetes mellitus and cardiovascular diseases.

Antioxidant Effect of Alpha-Lipoic Acid in 6-Hydroxydopamine Unilateral Intrastriatal Injected Rats.

The toxin 6-hydroxydopamine (6-OHDA) is a highly oxidizable dopamine (DA) analog that is widely used for reproducing several cell processes identified in Parkinson's disease (PD). Due to the close similarity of its neurotoxic mechanism to those of DA, it is suitable as a model for testing the effects of potentially neuroprotective drugs. This study aimed to evaluate the effect of alpha-lipoic acid (LA) on brain oxidative stress (OS) in unilateral intrastriatal (6-OHDA) injected rats. Forty male Wistar rats, four months old (220-260 g), were evaluated. Half of them received LA (35 mg/kg i.p.) from the start to the end of the experiment. On day 2 of the trial, ten LA-supplemented rats and ten non-LA-supplemented rats were subjected to the apomorphine test. Brain homogenates were evaluated for thiobarbituric acid-reactive substances (TBARS) and glutathione peroxidase (GPx) activity. The same evaluation procedures were repeated on day 14 with the remaining animals. An increased TBARS level and decreased GPx activity, suggestive for OS, were recorded in homogenates on day 14 vs. day 2 of the experiment in the 6-OHDA treated rats. The simultaneous application of LA mitigated these changes. Our study demonstrates that the low dose of LA could be of value for decreasing the OS of the neurotoxic 6-OHDA, supporting the need for further studies of the benefit of LA treatment in PD.

Evaluation of the anticonvulsant effect of novel melatonin derivatives in the intravenous pentylenetetrazol seizure test in mice.

The design of new pharmacologically active compounds with affinity to melatonin receptors has become an area of great interest during the last decade. Recently, we reported that newly synthesized melatonin derivatives, containing aroylhydrazone moiety in the indole scaffold, with the highest affinity to the elaborated pharmacophore model, possess an anticonvulsant activity in the maximal electroshock (MES) and 6Hz test in mice. We aimed further to explore the effect of these melatonin derivatives and the role of melatonin receptors on seizure threshold measured by the timed intravenous pentylenetetrazole (iv PTZ) infusion test in mice. Carbamazepine (CBZ) and melatonin were used as positive controls. Three out of six compounds, 3c, 3f, and 3e, respectively, dose-dependently increased the PTZ-induced seizure thresholds for myoclonic twitch, clonic, and tonic seizures comparable to the effect of CBZ and melatonin. The anticonvulsant effect of 3c, 3f, and 3e was blocked by the non-selective melatonin receptor antagonist luzindol suggesting the involvement of melatonin receptors in the activity of these compounds. Also docking study of 3c, 3f and 3e in the melatonin-binding site of melatonin receptor confirm the possible mechanism of action of these compounds involving melatonin receptors. Our previous and present results suggest that 3c, 3f, and 3e can be considered promising agents with anticonvulsant activity on melatonin receptors in the brain.

The place of inhaled corticosteroids in the treatment of chronic obstructive pulmonary disease: a narrative review.

Inhaled corticosteroids (ICSs) belong to the armament for treatment of chronic obstructive pulmonary disease (COPD) and as such, they are widely used in real life. This is a narrative review on evidence-based papers published in the English language listed in Medline between 1990 and March 2016 discussing ICS application in COPD. Recent meta-analyses clearly show that ICSs are able to decrease the rate of exacerbation and to delay the decline of lung function, although they do not prolong life, nor stop the progression of the disease. ICSs are included in guidelines for COPD treatment, exclusively in combination with bronch-15 odilators. However, adverse effects as pneumonia, cataracts, osteoporosis, etc. seem obvious. Newer studies show that patients with COPD are not a homogeneous population, and recently several phenotypes were identified, including asthma-COPD overlap syndrome (ACOS), among others. The efficacy of ICSs seems to be unequal for different subpopulations of patients with COPD and further research is needed to address a personalized approach in the treatment of COPD patients, and to 20 identify predictors for ICS treatment success. Usage of ICSs in patients with COPD needs to be précised especially in patients with COPD without asthma.

Differentiation of obese patients at moderate or higher Findrisc score based on their atherogenic index.

OBJECTIVES: The purpose of this study was to reveal different subgroups of patients with at least moderate risk of developing diabetes in the next 10 years, based on clustering of cardiovascular risk factors. METHODS: We performed a one-center cross-sectional study of adult patients (n = 109, median age 45 years) with Findrisc score of above 11 out of 26 maximum. We included in the cluster analysis anthropometrics, lipid and carbohydrate parameters obtained in oral glucose tolerance test (OGTT), insulin, C-peptide, creatinine, C-reactive protein, liver enzymes, beta-cell function, insulin sensitivity and insulin resistance (HOMA calculations). We also evaluated the atherogenic index of plasma (AIP). RESULTS: We identified three metabolic phenotypes of patients with at least moderate Findrisc score-one 'male' (cluster AM, n = 24), and two 'female' phenotypes (cluster AW, n = 9 and cluster BW, n = 76). Men were almost homogenous for their metabolic phenotype, with lower fat percentage than women (p < .05). Most of the women (cluster BW, n = 76) presented with better metabolic pattern i.e. lower insulin resistance, lower C-reactive protein, lower degree of obesity and visceral fat rating (p < .05), despite the higher fat percentage (p < .05). Some of the women, however, (cluster AW, n = 9) presented with parameters very similar to that of men (cluster AM) and significantly higher than in cluster BW. Despite the lack of significant differences in lipid parameters among clusters, AIP was significantly lower in cluster BW (p < .05). CONCLUSION: Most of the women presented with clearly less unfavorable atherogenic risk than men. Two different phenotypes of obese women with at least moderate Findrisc score were revealed, and the level of inflammation seems to be the main discriminant factor. Larger prospective studies are required to elucidate whether those are really two different pathogenically phenotypes or if they belong to the same phenotype's continuum.

Effect of zinc on the activity of Cu/Zn superoxide dismutase and lipid profile in Wistar rats.

AIM: The aim of the present study was to analyze the effect of zinc on the activity of Cu/ZnSOD, lipid profile and arterial blood pressure in male Wistar rats. MATERIAL AND METHODS: The study included 53 male Wistar rats with basal weight 190-210 g. The animals were divided into three groups and put on diets with different zinc content. Group I animals (G1, n = 18) were on a diet with zinc content 52 mg/kg, group II animals (G2, n = 18) were on a diet with zinc content 155 mg/kg corresponding to standard food and group III animals (G3, n = 17) received zinc supplementation (236 mg/kg diet). The activity of Cu/ZnSOD was measured in erythrocytes with RANSOD reactive (RANDOX). Zinc content in the laboratory chow and serum concentration of zinc and copper were analyzed by direct flame atomic-absorption spectrophotometry. Lipid profile was determined with reactives of ABX (France). Arterial blood pressure was measured on the rat's tail by an indirect method without anesthesia. RESULTS: Statistically significant decrease (p < 0.05) was found in the activity of Cu/ZnSOD in G1 animals (1993.51 +/- 303.01) compared with G2 animals (2307.07 +/- 240.23). There was a statistically significant increase (p < 0.05) of serum LDL in G3 (1.52 +/- 0.21) compared with G1 animals (1.09 +/- 0.27) and statistically significant increase in the serum triglycerides in G1 animals (1.19 +/- 0.22) compared with G3 animals (0.75 +/- 0.17). CONCLUSIONS: The results indicate that the activity of Cu/ZnSOD changes in relation to zinc diet and this correlates with the change in the arterial blood pressure. Lipid variables also are influenced and zinc supplementation leads to increase in the serum LDL and decrease in the serum triglycerides in Wistar rats.

Synthetic cannabimimetics in Bulgaria 2010-2013.

BACKGROUND: The manufacturing, distribution and use of synthetic cannabimimetics (SCs) have seen dynamic changes over the last few years, and have had an unprecedented growth. Forensic toxicologists in Bulgaria faced SCs for the first time in 2010, as compounds detected in seized blends. METHODS: This is a retrospective survey on the SCs seized in Bulgaria 2010-2013. RESULTS: The number of SCs increased progressively: 17 cases in 2010, 38 in 2011, 75 in 2012, and 80 in 2013. In Bulgaria, from 2010 to 2013, there were two cases of toxicologically proved intoxications (with JWH-018). JWH-018 was the most often detected SC in Bulgaria for the whole studied period. The most popular combination detected in 2013 was: UR-144+MAM-2201 with or without STS-135. Highly potent halogenated SCs appeared in 2013. 5F-AКB-48 (nearly 3 kg) was seized in 12 cases. Published data suggest that SCs may have more severe side effects than marijuana. Parallel adaptation of Bulgarian law with adoption of analog laws tried to meet the increased forensic challenges. CONCLUSIONS: Over the last decade, the rapid growth in the number and types of SCs distributed in Europe has challenged the capacity, and sometimes the credibility, of identification, risk assessment and control systems. Forensic toxicology needs to adapt in a timely manner, providing scientific basis of legislative changes.