Oxazolo[5,4-f]quinoxaline-type selective inhibitors of glycogen synthase kinase-3α (GSK-3α): Development and impact on temozolomide treatment of glioblastoma cells.

The 2-(3-pyridyl)oxazolo[5,4-f]quinoxalines CD-07 and FL-291 are ATP-competitive GSK-3 kinase inhibitors. Here, we investigated the impact of FL-291 on neuroblastoma cell viability and showed that treatment at 10 µM (i.e. ∼500 times the IC50 against the GSK-3 isoforms) has no significant effect on the viability of NSC-34 motoneuron-like cells. A study performed on primary neurons (non-cancer cells) led to similar results. The structures co-crystallized with GSK-3ß revealed similar binding modes for FL-291 and CD-07, with their hinge-oriented planar tricyclic system. Both GSK isoforms show the same orientations for the amino acids at the binding pocket except for Phe130 (α) and Phe67 (ß), leading to a larger pocket on the opposite side of the hinge region for the α isoform. Calculations of the thermodynamic properties of the binding pockets highlighted the required features of potential ligands; these should have a hydrophobic core (which could be larger in the case of GSK-3ß) surrounded by polar areas (a little more polar in the case of GSK-3α). A library of 27 analogs of FL-291 and CD-07 was thus designed and synthesized by taking advantage of this hypothesis. While the introduction of substituents at different positions of the pyridine ring, the replacement of the pyridine by other heterocyclic moieties, or the replacement of the quinoxaline ring by a quinoline moiety did not lead to any improvement, the replacement of the N-(thio)morpholino of FL-291/CD-07 by a slightly more polar N-thiazolidino led to a significant result. Indeed, the new inhibitor MH-124 showed clear selectivity for the α isoform, with IC50 values of 17 nM and 239 nM on GSK-3α and GSK-3ß, respectively. Finally, the efficacy of MH-124 was evaluated on two glioblastoma cell lines. Although MH-124 alone did not have a significant impact on cell survival, its addition to temozolomide (TMZ) significantly reduced the TMZ IC50 values on the cells tested. The use of the Bliss model allowed a synergy to be evidenced at certain concentrations.

Functions of Astrocytes under Normal Conditions and after a Brain Disease.

In the central nervous system (CNS) there are a greater number of glial cells than neurons (between five and ten times more). Furthermore, they have a greater number of functions (more than eight functions). Glia comprises different types of cells, those of neural origin (astrocytes, radial glia, and oligodendroglia) and differentiated blood monocytes (microglia). During ontogeny, neurons develop earlier (at fetal day 15 in the rat) and astrocytes develop later (at fetal day 21 in the rat), which could indicate their important and crucial role in the CNS. Analysis of the phylogeny reveals that reptiles have a lower number of astrocytes compared to neurons and in humans this is reversed, as there have a greater number of astrocytes compared to neurons. These data perhaps imply that astrocytes are important and special cells, involved in many vital functions, including memory, and learning processes. In addition, astrocytes are involved in different mechanisms that protect the CNS through the production of antioxidant and anti-inflammatory proteins and they clean the extracellular environment and help neurons to communicate correctly with each other. The production of inflammatory mediators is important to prevent changes in brain homeostasis. On the contrary, excessive, or continued production appears as a characteristic element in many diseases, such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), and in neurodevelopmental diseases, such as bipolar disorder, schizophrenia, and autism. Furthermore, different drugs and techniques have been developed to reverse oxidative stress and/or excess of inflammation that occurs in many CNS diseases, but much remains to be investigated. This review attempts to highlight the functional relevance of astrocytes in normal and neuropathological conditions by showing the molecular and cellular mechanisms of their role in the CNS.

Improvement of Vascular Insulin Sensitivity by Ranolazine.

Ranolazine (RN) is a drug used in the treatment of chronic coronary ischemia. Different clinical trials have shown that RN behaves as an anti-diabetic drug by lowering blood glucose and glycosylated hemoglobin (HbA1c) levels. However, RN has not been shown to improve insulin (IN) sensitivity. Our study investigates the possible facilitating effects of RN on the actions of IN in the rabbit aorta. IN induced vasodilation of the abdominal aorta in a concentration-dependent manner, and this dilatory effect was due to the phosphorylation of endothelial nitric oxide synthase (eNOS) and the formation of nitric oxide (NO). On the other hand, IN facilitated the vasodilator effects of acetylcholine but not the vasodilation induced by sodium nitroprusside. RN facilitated all the vasodilatory effects of IN. In addition, IN decreased the vasoconstrictor effects of adrenergic nerve stimulation and exogenous noradrenaline. Both effects were in turn facilitated by RN. The joint effect of RN with IN induced a significant increase in the ratio of p-eNOS/eNOS and pAKT/AKT. In conclusion, RN facilitated the vasodilator effects of IN, both direct and induced, on the adrenergic system. Therefore, RN increases vascular sensitivity to IN, thus decreasing tissue resistance to the hormone, a key mechanism in the development of type II diabetes.

Facilitation of Insulin Effects by Ranolazine in Astrocytes in Primary Culture.

Ranolazine (Rn) is a drug used to treat persistent chronic coronary ischemia. It has also been shown to have therapeutic benefits on the central nervous system and an anti-diabetic effect by lowering blood glucose levels; however, no effects of Rn on cellular sensitivity to insulin (Ins) have been demonstrated yet. The present study aimed to investigate the permissive effects of Rn on the actions of Ins in astrocytes in primary culture. Ins (10-8 M), Rn (10-6 M), and Ins + Rn (10-8 M and 10-6 M, respectively) were added to astrocytes for 24 h. In comparison to control cells, Rn and/or Ins caused modifications in cell viability and proliferation. Rn increased protein expression of Cu/Zn-SOD and the pro-inflammatory protein COX-2 was upregulated by Ins. On the contrary, no significant changes were found in the protein expression of NF-κB and IκB. The presence of Rn produced an increase in p-ERK protein and a significant decrease in COX-2 protein expression. Furthermore, Rn significantly increased the effects of Ins on the expression of p-AKT, p-eNOS, p-ERK, Mn-SOD, and PPAR-γ. In addition, Rn + Ins produced a significant decrease in COX-2 expression. In conclusion, Rn facilitated the effects of insulin on the p-AKT, p-eNOS, p-ERK, Mn-SOD, and PPAR-γ signaling pathways, as well as on the anti-inflammatory and antioxidant effects of the hormone.

The Link between Oxidative Stress, Redox Status, Bioenergetics and Mitochondria in the Pathophysiology of ALS.

Amyotrophic lateral sclerosis (ALS) is the most common neurodegenerative disease of the motor system. It is characterized by the degeneration of both upper and lower motor neurons, which leads to muscle weakness and paralysis. ALS is incurable and has a bleak prognosis, with median survival of 3-5 years after the initial symptomatology. In ALS, motor neurons gradually degenerate and die. Many features of mitochondrial dysfunction are manifested in neurodegenerative diseases, including ALS. Mitochondria have shown to be an early target in ALS pathophysiology and contribute to disease progression. Disruption of their axonal transport, excessive generation of reactive oxygen species, disruption of the mitochondrial structure, dynamics, mitophagy, energy production, calcium buffering and apoptotic triggering have all been directly involved in disease pathogenesis and extensively reported in ALS patients and animal model systems. Alterations in energy production by motor neurons, which severely limit their survival capacity, are tightly linked to the redox status and mitochondria. The present review focuses on this link. Placing oxidative stress as a main pathophysiological mechanism, the molecular interactions and metabolic flows involved are analyzed. This leads to discussing potential therapeutic approaches targeting mitochondrial biology to slow disease progression.

Action of low doses of Aspirin in Inflammation and Oxidative Stress induced by aß1-42 on Astrocytes in primary culture.

Aspirin has been used as anti-inflammatory and anti-aggregate for decades but the precise mechanism(s) of action after the presence of the toxic peptide Aß1-42 in cultured astrocytes remains poorly resolved. Here we use low-doses of aspirin (10-7 M) in astrocytes in primary culture in presence or absence of Aß1-42 toxic peptide. We noted an increase of cell viability and proliferation with or without Aß1-42 peptide presence in aspirin treated cells. In addition, a decrease in apoptosis, determined by Caspase 3 activity and the expression of Cyt c and Smac/Diablo, were detected. Also, aspirin diminished necrosis process (LDH levels), pro-inflammatory mediators (IL-ß and TNF-α) and NF-ᴋB protein expression, increasing anti-inflammatory PPAR-γ protein expression, preventing Aß1-42 toxic effects. Aspirin inhibited COX-2 and iNOS without changes in COX-1 expression, increasing anti-oxidant protein (Cu/Zn-SOD and Mn-SOD) expression in presence or absence of Aß1-42. Taken together, our results show that aspirin, at low doses increases cell viability by decreasing inflammation and oxidative stress, preventing the deleterious effects of the Aß1-42 peptide on astrocytes in primary culture. The use of low doses of aspirin may be more suitable for Alzheimer's disease.

Protective Effects of Foam Rolling against Inflammation and Notexin Induced Muscle Damage in Rats.

It is known that high-intensity exercise can cause inflammation and damage in muscle tissue, and in recent years, physical therapists and fitness professionals have begun to use foam rolling as a recovery method to improve performance. Despite the lack of basic science studies to support or refute the efficacy of foam rolling, the technique is very widely used in the sports world. In this respect, we investigated whether foam rolling could attenuate muscle damage and inflammation. Female Wistar rats were assigned to control (C), foam rolling (FR), notexin without foam rolling (N) and notexin with foam rolling (NFR) groups. A 4.5 x 2 cm foam roller was used to massage their hind legs (two 60-second repetitions twice a day for 3 days). Motor function tests (Balance Beam Test and Grip strength) were used. We detected an increase in time and foot faults when crossing a beam in the N group compared to C and FR rats. In contrast, a significant decrease was detected in both tests in NFR compared to N rats. Muscle power was measured with a grip strength test and better performance was detected in NFR rats compared to N rats. Furthermore, an increase of pro-inflammatory proteins was noted in the N group, while there was a decrease in the NFR group. On the contrary, an increase in PPAR-γ (anti-inflammatory protein) in the NFR group compared to the N group demonstrates the anti-inflammatory properties of the foam rolling technique. In summary, applying foam rolling after damage has benefits such as an increase in anti-inflammatory proteins and a reduction of pro-inflammatory proteins, resulting in muscle recovery and better performance.

Function of Glia in Aging and the Brain Diseases.

Microglia cells during aging, neurodegeneration and neuroinflammation show different morphological and transcriptional profiles (related to axonal direction and cell adhesion). Furthermore, expressions of the receptors on the surface and actin formation compared to young are also different. This review delves into the role of glia during aging and the development of the diseases. The susceptibility of different regions of the brain to disease are linked to the overstimulation of signals related to the immune system during aging, as well as the damaging impact of these cascades on the functionality of different populations of microglia present in each region of the brain. Furthermore, a decrease in microglial phagocytosis has been related to many diseases and also has been detected during aging. In this paper we also describe the role of glia in different illness, such as AD, ALS, pain related disorders, cancer, developmental disorders and the problems produced by opening of the blood brain barrier. Future studies will clarify many points planted by this review.

Chronic exercise impairs nitric oxide pathway in rabbit carotid and femoral arteries.

KEY POINTS: Some of the beneficial effects of exercise in preventing vascular related diseases are mediated by the enhancement of endothelial function where the role of nitric oxide (NO) is well documented, although the relevance of calcium activated potassium channels is not fully understood. The impact of oxidative stress induced by training on endothelial function remains to be clarified. By evaluating different endothelial vasodilator pathways on two vascular beds in a rabbit model of chronic exercise, we found a decreased NO bioavailability and endothelial nitric oxide synthase expression in both carotid and femoral arteries. Physical training induced carotid endothelial dysfunction as a result of an increase in oxidative stress and a reduction in superoxide dismutase expression. In the femoral artery, the lower production of NO was counteracted by an increased participation of large conductance calcium activated potassium channels, preventing endothelial dysfunction. ABSTRACT: The present study aimed to evaluate the effects of chronic exercise on vasodilator response in two different arteries. Rings of carotid and femoral arteries from control and trained rabbits were suspended in organ baths for isometric recording of tension. Endothelial nitric oxide synthase (eNOS), Cu/Zn and Mn-superoxide dismutase (SOD), and large conductance calcium activated potassium (BKCa) channel protein expression were measured by western blotting. In the carotid artery, training reduced the relaxation to ACh (10-9 to 3 × 10-6  m) that was reversed by N-acetylcysteine (10-3  m). l-NAME (10-4  m) reduced the relaxation to ACh in both groups, although the effect was lower in the trained group (in mean ± SEM, 39 ± 2% vs. 28 ± 3%). Physical training did not modify the relaxation to ACh in femoral arteries, although the response to l-NAME was lower in the trained group (in mean ± SEM, 41 ± 5% vs. 17 ± 2%). Charybdotoxin (10-7  m) plus apamin (10-6  m) further reduced the maximal relaxation to ACh only in the trained group. The remaining relaxation in both carotid and femoral arteries was abolished by KCl (2 × 10-2  m) and BaCl2 (3 × 10-6  m) plus ouabain (10-4  m) in both groups. Physical training decreased eNOS expression in both carotid and femoral arteries and Cu/Zn and Mn-SOD expression only in the carotid artery. BKCa channels were overexpressed in the trained group in the femoral artery. In conclusion, chronic exercise induces endothelial dysfunction in the carotid artery as a result of oxidative stress. In the femoral artery, it modifies the vasodilator pathways, enhancing the participation of BKCa channels, thus compensating for the impairment of NO-mediated vasodilatation.

Neuronal Effects of Sugammadex in combination with Rocuronium or Vecuronium.

Rocuronium (ROC) and Vecuronium (VEC) are the most currently used steroidal non-depolarizing neuromuscular blocking (MNB) agents. Sugammadex (SUG) rapidly reverses steroidal NMB agents after anaesthesia. The present study was conducted in order to evaluate neuronal effects of SUG alone and in combination with both ROC and VEC. Using MTT, CASP-3 activity and Western-blot we determined the toxicity of SUG, ROC or VEC in neurons in primary culture. SUG induces apoptosis/necrosis in neurons in primary culture and increases cytochrome C (CytC), apoptosis-inducing factor (AIF), Smac/Diablo and Caspase 3 (CASP-3) protein expression. Our results also demonstrated that both ROC and VEC prevent these SUG effects. The protective role of both ROC and VEC could be explained by the fact that SUG encapsulates NMB drugs. In BBB impaired conditions it would be desirable to control SUG doses to prevent the excess of free SUG in plasma that may induce neuronal damage. A balance between SUG, ROC or VEC would be necessary to prevent the risk of cell damage.

Bifidobacterium pseudocatenulatum CECT 7765 supplementation restores altered vascular function in an experimental model of obese mice.

Aims.Bifidobacterium pseudocatenulatum CECT 7765 improves metabolic and immunological altered functions in high fat fed mice, however little is known about the effects of potential probiotics on vascular reactivity. The aim of the present study was to investigate the effects of a potential probiotic strain, Bifidobacterium pseudocatenulatum CECT 7765, on vascular response in obese mice. Methods. Aorta samples were obtained from mice, which were divided into three groups: a control group, receiving a standard diet; an obese group, receiving a high-fat diet; and an obese group receiving high-fat diet and a daily dose of B. pseudocatenulatum CECT 7765 by oral gavage. Aortic rings were suspended in organ baths for isometric recording of tension. mRNA expression of eNOS was evaluated by real-time polymerase chain reaction. Results. Contractions induced by KCl, noradrenaline and thromboxane analogue were 33%, 30% and 45% lower respectively in aortic rings from obese mice. Bifidobacteria administration reversed this effect. eNOS inhibition increased the response to noradrenaline in the three groups with a significant lower magnitude in aortic rings from obese mice receiving bifidobacteria supplement. Acetylcholine caused a greater vasodilation in aorta from obese group (46±3% for control and 69±4% for obese group; p<0.05) and bifidobacteria reversed it (57±5%). Response to sodium nitroprusside was displaced 2.9 times to the left in a parallel manner in obese group. Relaxation to sodium nitroprusside remained unchanged in the bifidobacteria fed group. There was about five-fold decreased mRNA expression of eNOS in aortic segments from the group receiving bifidobacteria. Conclusion.Bifidobacterium pseudocatenulatum CECT 7765 restores the obesity-induced altered vascular function mainly by reducing nitric oxide release.

Astrocytes protect neurons from Aß1-42 peptide-induced neurotoxicity increasing TFAM and PGC-1 and decreasing PPAR-γ and SIRT-1.

One of the earliest neuropathological events in Alzheimer's disease is accumulation of astrocytes at sites of Aß1-42 depositions. Our results indicate that Aß1-42 toxic peptide increases lipid peroxidation, apoptosis and cell death in neurons but not in astrocytes in primary culture. Aß1-42-induced deleterious neuronal effects are not present when neurons and astrocytes are mixed cultured. Stimulation of astrocytes with toxic Aß1-42 peptide increased p-65 and decreased IκB resulting in inflammatory process. In astrocytes Aß1-42 decreases protein expressions of sirtuin 1 (SIRT-1) and peroxisome proliferator-activated receptor γ (PPAR-γ) and over-expresses peroxisome proliferator-activated receptor γ coactivator 1 (PGC-1) and mitochondrial transcription factor A (TFAM), protecting mitochondria against Aß1-42-induced damage and promoting mitochondrial biogenesis. In summary our data suggest that astrocytes may have a key role in protecting neurons, increasing neural viability and mitochondrial biogenesis, acquiring better oxidative stress protection and perhaps modulating inflammatory processes against Aß1-42 toxic peptide. This might be a sign of a complex epigenetic process in Alzheimer's disease development.

Levamisole Impairs Vascular Function by Blocking α-Adrenergic Receptors and Reducing NO Bioavailability in Rabbit Renal Artery.

Levamisole is an anthelmintic drug restricted to veterinary use but is currently detected as the most widely used cocaine cutting agent in European countries. Levamisole-adulterated cocaine has been linked to acute kidney injury, marked by a decrease in glomerular filtration rate, which involves reduced renal blood flow, but data on the alteration of renovascular response produced by levamisole are scarce. Renal arteries were isolated from healthy rabbits and used for isometric tension recording in organ baths and protein analysis. We provide evidence that depending on its concentration, levamisole modulates renovascular tone by acting as a non-selective α-adrenergic receptor blocker and down-regulates α1-adrenoceptor expression. Furthermore, levamisole impairs the endothelium-dependent relaxation induced by acetylcholine without modifying endothelial nitric oxide synthase (eNOS) expression. However, exposure to superoxide dismutase (SOD) partially prevents the impairment of ACh-induced relaxation by levamisole. This response is consistent with a down-regulation of SOD1 and an up-regulation of NADPH oxidase 4 (Nox4), suggesting that endothelial NO loss is due to increased local oxidative stress. Our findings demonstrate that levamisole can interfere with renal blood flow and the coordinated response to a vasodilator stimulus, which could worsen the deleterious consequences of cocaine use.

Stress hormones promote growth of B16-F10 melanoma metastases: an interleukin 6- and glutathione-dependent mechanism.

BACKGROUND: Interleukin (IL)-6 (mainly of tumor origin) activates glutathione (GSH) release from hepatocytes and its interorgan transport to B16-F10 melanoma metastatic foci. We studied if this capacity to overproduce IL-6 is regulated by cancer cell-independent mechanisms. METHODS: Murine B16-F10 melanoma cells were cultured, transfected with red fluorescent protein, injected i.v. into syngenic C57BL/6J mice to generate lung and liver metastases, and isolated from metastatic foci using high-performance cell sorting. Stress hormones and IL-6 levels were measured by ELISA, and CRH expression in the brain by in situ hybridization. DNA binding activity of NF-κB, CREB, AP-1, and NF-IL-6 was measured using specific transcription factor assay kits. IL-6 expression was measured by RT-PCR, and silencing was achieved by transfection of anti-IL-6 small interfering RNA. GSH was determined by HPLC. Cell death analysis was distinguished using fluorescence microscopy, TUNEL labeling, and flow cytometry techniques. Statistical analyses were performed using Student's t test. RESULTS: Plasma levels of stress-related hormones (adrenocorticotropin hormone, corticosterone, and noradrenaline) increased, following a circadian pattern and as compared to non-tumor controls, in mice bearing B16-F10 lung or liver metastases. Corticosterone and noradrenaline, at pathophysiological levels, increased expression and secretion of IL-6 in B16-F10 cells in vitro. Corticosterone- and noradrenaline-induced transcriptional up-regulation of IL-6 gene involves changes in the DNA binding activity of nuclear factor-κB, cAMP response element-binding protein, activator protein-1, and nuclear factor for IL-6. In vivo inoculation of B16-F10 cells transfected with anti-IL-6-siRNA, treatment with a glucocorticoid receptor blocker (RU-486) or with a ß-adrenoceptor blocker (propranolol), increased hepatic GSH whereas decreased plasma IL-6 levels and metastatic growth. Corticosterone, but not NORA, also induced apoptotic cell death in metastatic cells with low GSH content. CONCLUSIONS: Our results describe an interorgan system where stress-related hormones, IL-6, and GSH coordinately regulate metastases growth.

Sugammadex, a neuromuscular blockade reversal agent, causes neuronal apoptosis in primary cultures.

Sugammadex, a γ-cyclodextrin that encapsulates selectively steroidal neuromuscular blocking agents, such as rocuronium or vecuronium, has changed the face of clinical neuromuscular pharmacology. Sugammadex allows a rapid reversal of muscle paralysis. Sugammadex appears to be safe and well tolerated. Its blood-brain barrier penetration is poor (< 3% in rats), and thus no relevant central nervous toxicity is expected. However the blood brain barrier permeability can be altered under different conditions (i.e. neurodegenerative diseases, trauma, ischemia, infections, or immature nervous system). Using MTT, confocal microscopy, caspase-3 activity, cholesterol quantification and Western-blot we determine toxicity of Sugammadex in neurons in primary culture. Here we show that clinically relevant sugammadex concentrations cause apoptotic/necrosis neuron death in primary cultures. Studies on the underlying mechanism revealed that sugammadex-induced activation of mitochondria-dependent apoptosis associates with depletion of neuronal cholesterol levels. Furthermore SUG increase CytC, AIF, Smac/Diablo and CASP-3 protein expression in cells in culture. Potential association of SUG-induced alteration in cholesterol homeostasis with oxidative stress and apoptosis activation occurs. Furthermore, resistance/sensitivity to oxidative stress differs between neuronal cell types.

Protective action of ultrasound-guided electrolysis technique on the muscle damage induced by notexin in rats.

It is known that exercise can be one of the causes of muscular damage. In recent times, physiotherapists and medical professionals have been employing USGET techniques to stimulate muscle recovery to improve its performance after the injury. We pretend to analyse if the Ultrasound-guided electrolysis (USGET) technique could reduce muscle damage, inflammation, and pain in the present study. Female Wistar rats were assigned to one of three different groups: control (C), notexin (NOT) and notexin with USGET (electrolysis at 6mA) (NOT+USGET). We used the USGT technique, based on electrical stimulation with a continuous current of 4 pulses at an intensity of 6 mA for 5 seconds, conveyed to the muscle. The response was tested with motor function tests. In these tests, we could observe an increase in time and foot faults when crossing a beam in the NOT group compared to C group rats. On the other hand, a significant decrease in both variables was detected in the NOT+USGET compared to the NOT group. Muscle power was measured with a grip strength test, obtaining far better performances in NOT+USGET rats when compared to NOT rats. Moreover, the USGET technique prevented the increase of pro-inflammatory proteins IL-6 and chemokines CCL3 (Chemokine (C-C motif) ligand 3), CCL4 (Chemokine (C-C motif) ligand 4), and CCL5 (Chemokine (C-C motif) ligand 5) with their receptor CCR5 (C-C chemokine receptor type 5), induced by notexin in the quadriceps. At the same time, the study evidenced a decrease in both CCR8 (C-C chemokine receptor type 5,) and NF-ᴋB (nuclear factor- ᴋB) expressions after USGET treatment. On the other hand, we obtained evidence that demonstrated anti-inflammatory properties of the USGET technique, thus being the increase in IL-10 (Interleukin 10) and IL-13 (Interleukin 13) in the NOT+USGET group compared to the NOT group. Furthermore, when applying NSGET after damage, an increase in anti-inflammatory mediators and reduction of pro-inflammatory mediators, which, overall, promoted muscle regeneration, was observed. These results support the idea that the NSGET technique improves muscle recovery after toxic damages, which would justify its employment.

Deleterious effects of levamisole, a cocaine adulterant, in rabbit aorta.

Levamisole, a veterinary anthelmintic drug, is one of the most widely used and dangerous cocaine adulterants. Like cocaine, levamisole acutely blocks noradrenaline reuptake but with much less potency, although its vascular effects are not well known. In this study, we evaluated the vascular effects of levamisole and cocaine in rabbit aortic rings used for isometric recording of tension in organ baths and protein expression by western blot. Our results indicated that levamisole (10-5-10-3 M) induced a concentration-dependent relaxation in rings precontracted with noradrenaline (10-7-3 × 10-7 M). Furthermore, it reduced the contractile response to phenylephrine (10-9-3 × 10-5 M) that was not modified by cocaine (10-5-10-4 M), and reduced α1-adrenergic receptor expression. Levamisole (10-6-10-4 M) produced a potentiation of the electrical field stimulation that was not further enhanced by the combination of both drugs. However, high concentrations of levamisole (10-3 M) abolished adrenergic neurotransmission whether administered alone or with cocaine (10-4 M). In addition, levamisole (10-5-10-3 M) also decreased endothelium-dependent relaxation to acetylcholine that was not further impaired by cocaine (10-4 M), and that was partially reversed by superoxide dismutase (SOD, 200 U/ml). These results demonstrate that levamisole has a dual effect on the adrenergic system, and its effects are independent of the presence of cocaine. At lower concentrations, it enhances the contractile sympathetic response by blocking presynaptic α2-adrenergic receptors, while at high concentrations, the effect of the antagonism of α1-adrenergic receptor prevails. In addition, levamisole induces endothelial dysfunction by reducing NO bioavailability, and this effect could be in part mediated by oxidative stress.

Free [NADH]/[NAD(+)] regulates sirtuin expression.

Sirtuins are deacetylases involved in metabolic regulation and longevity. Our aim was to test the hypothesis that they are subjected to redox regulation by the [NADH]/[NAD(+)] ratio. We used NIH3T3 fibroblasts in culture, Drosophila fed with or without ethanol and exercising rats. In all three models an increase in [NADH]/[NAD(+)] came up with an increased expression of sirtuin mRNA and protein. PGC-1α (a substrate of sirtuins) protein level was significantly increased in fibroblasts incubated with lactate and pyruvate but this effect was lost in fibroblasts obtained from sirtuin-deficient mice. We conclude that the expression of sirtuins is subject to tight redox regulation by the [NADH]/[NAD(+)] ratio, which is a major sensor for metabolite availability conserved from invertebrates to vertebrates.

Inflammatory Chemokines Expression Variations and Their Receptors in APP/PS1 Mice.

BACKGROUND: In Alzheimer's disease (AD), an increase in inflammation is distinctive. Amyloid precursor protein plus presenilin-1 (APP/PS1 mice) is a model for this illness. Chemokines secreted by central nervous system (CNS) cells could play multiple important roles in AD. Data looking for the chemokines involved in inflammatory mechanisms are lacking. To understand the changes that occur in the inflammation process in AD, it is necessary to improve strategies to act on specific inflammatory targets. OBJECTIVE: Chemokines and their receptors involved in phagocytosis, demyelination, chemotaxis, and coagulation were the objective of our study. METHODS: Female APPswe/PS1 double-transgenic mice (B6C3-Tg) were used and cortex brain from 20-22-month-old mice obtained and used to quantify chemokines and chemokine receptors expression using RT-PCR technique. RESULTS: Significant inflammatory changes were detected in APP/PS1 compared to wild type mice. CCR1, CCR3, CCR4, and CCR9 were elevated, and CCR2 were decreased compared with wild type mice. Their ligands CCL7, CCL11, CCL17, CCL22, CCL25, and CXCL4 showed an increase expression; however, changes were not observed in CCL2 in APP/PS1 compared to wild type mice. CONCLUSION: This change in expression could explain the differences between AD patients and elderly people without this illness. This would provide a new strategy for the treatment of AD, with the possibility to act in specific inflammatory targets.

PPARγ as an indicator of vascular function in an experimental model of metabolic syndrome in rabbits.

BACKGROUND AND AIMS: Underlying mechanisms associated with vascular dysfunction in metabolic syndrome (MetS) remain unclear and can even vary from one vascular bed to another. METHODS: In this study, MetS was induced by a high-fat, high-sucrose diet, and after 28 weeks, aorta and renal arteries were removed and used for isometric recording of tension in organ baths, protein expression by Western blot, and histological analysis to assess the presence of atherosclerosis. RESULTS: MetS induced a mild hypertension, pre-diabetes, central obesity and dyslipidaemia. Our results indicated that MetS did not change the contractile response in either the aorta or renal artery. Conversely, vasodilation was affected in both arteries in a different way. The aorta from MetS showed vascular dysfunction, including lower response to acetylcholine and sodium nitroprusside, while the renal artery from MetS presented a preserved relaxation to acetylcholine and an increased sensitivity to sodium nitroprusside. We did not find vascular oxidative stress in the aorta from MetS, but we found a significant decrease in PPARγ, phospho-Akt (p-Akt) and phospho-eNOS (p-eNOS) protein expression. On the other hand, we found oxidative stress in the renal artery from MetS, and PPARγ, Akt and p-Akt were overexpressed. No evidence of atherosclerosis was found in arteries from MetS. CONCLUSIONS: MetS affects vascular function differently depending on the vessel. In the aorta, it decreases both the vasodilation and the expression of the PPARγ/Akt/eNOS pathway, while in the renal artery, it increases the expression of PPARγ/Akt signalling pathway without decreasing the vasodilation.