Funciones protectoras de los astrocitos en la inflamación y el estrés oxidativo cerebral

La enfermedad de Alzheimer (EA) es una enfermedad neurodegenerativa que se presenta con mayor prevalencia en la población anciana. Afecta a alrededor de 37 millones de personas en todo el mundo. Desde el punto de vista inmunohistoquímico, la EA se caracteriza por la presencia de placas neuríticas (con el péptido tóxico Aβ1-42, entre otros) y ovillos neurofibrilares en diversas áreas del cerebro, responsables de la pérdida neuronal, el deterioro de las conexiones sinápticas y la gliosis reactiva causando la inflamación característica de esta enfermedad. Resultados previos indican que los astrocitos son células de protección para las neuronas y que podrían proteger de la inflamación y del estrés oxidativo inducido por el péptido Aβ1-42 en las células cerebrales en cultivo primario. También el fármaco Ranolazina tendría un efecto protector ante el péptido tóxico Aβ1-42. Los resultados de esta tesis demuestran que el péptido tóxico (Aβ1-42) disminuye la viabilidad celular y aumenta la apoptosis y la peroxidación lipídica (MDA) en neuronas en cultivo primario, pero no produce cambios ni en astrocitos ni en neuronas en cultivo mixto (neuronas-astrocitos), indicando un papel protector de los astrocitos sobre las neuronas frente al péptido tóxico Aβ1-42. En astrocitos en cultivo primario se produce un aumento de la biogénesis mitocondrial y de la expresión de la proteína Mn-SOD en presencia del péptido tóxico. Ambos mecanismos podrían contribuir a la disminución del estrés oxidativo produciendo mayor protección neuronal. El aumento de la expresión de la proteína p-65 (NF-κB) que observamos en astrocitos podría no ser indicativo de muerte neuronal sino un mecanismo protector a través de un aumento en la fosforilación de PGC-1 conduciendo al incremento de los niveles de TFAM y por ende a la biogénesis mitocondrial. Además Aβ1-42 disminuye la expresión proteica de SIRT-1 en cultivos primarios de astrocitos, produciendo un aumento de la expresión de PGC-1 y TFAM que resulta en un incremento de la biogénesis mitocondrial, disminuyendo la expresión de PPAR-γ. Por otra parte, el fármaco Ranolazina induce un aumento en la viabilidad y proliferación de los astrocitos, disminuyendo la muerte celular mediante la reducción de la liberación de LDH y de la apoptosis gracias a la reducción de la expresión de la proteína Smac/Diablo, Citocromo c y de la actividad de la Caspasa 3. No así en neuronas en cultivo primario. El fármaco Rn produce disminución de mediadores pro-inflamatorios como IL-1β y TNF-α, aumenta los anti-inflamatorios como la proteína PPAR-γ, e incrementa la expresión de las proteínas anti-oxidantes Cu/Zn-SOD y Mn-SOD en los astrocitos en cultivo primario sin encontrarse ningún cambio en lo que respecta a las neuronas en cultivo primario. En conclusión, nuestros resultados indican que los astrocitos deben tener un papel clave en la protección de las neuronas frente al péptido tóxico Aβ1-42 mediante el aumento de la viabilidad celular y la biogénesis mitocondrial, obteniendo una mejor protección frente al estrés oxidativo y quizás modulando los procesos inflamatorios. Además, el fármaco Ranolazina tiene un efecto protector frente al péptido tóxico en astrocitos y no en neuronas en cultivo primario, por lo que la protección producida por la Ranolazina en la neurodegeneración estaría realizada a través de los astrocitos protegiendo en última instancia a las neuronas

Material multimedia en español, valenciano e inglés para la clase práctica de Auscultación Cardíaca

En los últimos años, el uso de material multimedia se ha convertido en una práctica habitual en las aulas, ya que permite que los estudiantes mantengan y mejoren la atención en clase, así como una mayor comprensión de los conceptos adquiridos. Es por ello, que hemos llevado a cabo un vídeo en español, valenciano e inglés de la clase práctica de Auscultación Cardíaca en el Grado de Medicina y otros grados afines dentro de las Ciencias de la Salud. El vídeo se realizó en los tres idiomas utilizados (español, inglés y valenciano) en los grupos del Grado de Medicina. Se trata un procedimiento clínico de exploración física ampliamente utilizado en clínica, pero que al mismo tiempo presenta cierta dificultad para el estudiante. Los objetivos son aprender a localizar exactamente los focos de auscultación cardíaca (mitral, aórtico, tricuspídeo y pulmonar) y el reconocimiento de cada uno de los ruidos cardíacos. Este material multimedia permite que los estudiantes mantengan y mejoren la atención en clase y aumente su capacidad de aprendizaje, tal y como ha sido mostrado en las encuestas realizadas. Su uso en la actualidad supone una ayuda para los estudiantes que tengan que realizar esta práctica de modo no presencial

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

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

Changes in Chemokines and Chemokine Receptors Expression in a Mouse Model of Alzheimer's Disease

The amyloid precursor protein plus presenilin-1 (APP/PS1) mice are a frequently-used model for Alzheimer's disease studies (AD). However, the data relevant to which proteins are involved in inflammatory mechanism are not sufficiently well-studied using the AD mouse model. Using behavioral studies, quantitative RT-PCR and Western-blot techniques, significant findings were determined by the expression of proteins involved in inflammation comparing APP/PS1 and Wild type mice. Increased GFAP expression could be associated with the elevation in number of reactive astrocytes. IL-3 is involved in inflammation and ABDF1 intervenes normally in the transport across cell membranes and both were found up-regulated in APP/PS1 mice compared to Wild type mice. Furthermore, CCR5 expression was decreased and both CCL3 and CCL4 chemokines were highly expressed indicating a possible gliosis and probably an increase in chemotaxis from lymphocytes and T cell generation. We also noted for the first time, a CCR8 increase expression with diminution of its CCL1 chemokine, both normally involved in protection from bacterial infection and demyelination. Control of inflammatory proteins will be the next step in understanding the progression of AD and also in determining the mechanisms that can develop in this disease

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

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-3β revealed similar binding modes for FL-291 and CD-07, with their hingeoriented planar tricyclic system. Both GSK isoforms show the same orientations for the amino acids at the binding pocket except for Phe130 (α) and Phe67 (β), 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-3β) surrounded by polar areas (a little more polar in the case of GSK-3α). A library of 27 analogs of FL-291 and CD07 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-3β, 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 concentration

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

Astrocytes and its good relation with neurons

Astrocytes and its good relation with neuron

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 diabete