21 research outputs found

    Erythrocytes as regulators of blood vessel tone

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    A drop in oxygen partial pressure results in elevation of blood vessel diameter. It has been demonstrated that isolated vessels exhibit this unique feature only when they are perfused in the presence of erythrocytes. More recently, it was shown that haemoglobin plays a key role in oxygen sensing. Its deoxygenated form interacts with band 3 protein, triggering the cascade of non-identified intracellular signals involved in nitric oxide production and release of ATP interacting with P2Y purinergic receptors in endothelial cells. In this review, we summarize the data on mechanisms of ATP release from erythrocytes, as well as on its physiological and pathophysiological implications

    Neuromodulatory Effect of BDNF in Spinal Cord Injury

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    The neuromodulatory effect of brain-derived neurotrophic factor (BDNF) in spinal cord injury (SCI) is a topic of significant interest. BDNF, a neurotrophic factor, plays a crucial role in promoting neuronal survival, axonal growth, and synaptic plasticity in the central nervous system. In SCI, BDNF has been shown to enhance the survival of injured neurons and stimulate axonal growth through the activation of downstream signaling pathways. Additionally, BDNF exhibits potent anti-inflammatory effects, reducing neuroinflammation and secondary damage. The timing and duration of BDNF administration are critical, with early intervention showing better outcomes. However, the optimal dosage and frequency of BDNF administration remain to be determined. Further research is needed to fully understand the potential of BDNF as a therapeutic agent for enhancing functional recovery and promoting neuroplasticity in individuals with SCI

    Sinomenine as a novel analgesic : mechanisms and applications

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    Chronic pain of various origins is a major health care issue affecting a large patient population, also bring significant social and economic cost on the society. Work presented in this thesis concerns novel methods of treatments for chronic pain using experimental models. Sinomenine is a chemical compound isolated originally from the root of the plant Sinomenium Acutum native to China and Japan. It is an alkaloid, structurally belongs to the morphine family. The root of Sinomenium Acutum, known as Qingteng, has been traditionally used in China as a medical remedy for condition likely to be rheumatism. Sinomenine is currently approved in China as an anti-rheumatic agent for clinical sue. In first part of the thesis, we studied the analgesic effect of sinomenine in chronic experimental pain models of neuropathic and arthritic pain. We showed that sinomenine has significant analgesic effects in rat and mouse models of neuropathic pain as well as in a mouse model (collagen antibody-induced arthritis model, CAIA) of arthritic pain. More importantly, the effect of sinomenine on neuropathic and arthritic pain is maintained upon repeated chronic administration without signs of tolerance or dependence. In the second part of the thesis, we examined the possible application of sinomenine as an analgesic, we showed that combination with sinomenine with gabapentin, a clinically used drug treating neuropathic pain, produced marked synergistic interaction in rat and mouse models of neuropathic pain and such synergism can still be observed upon repeated administration without signs of tolerance and dependence. We can also show a similar synergistic interaction between gabapentin and dextromethorphan, a low affinity non-competitive NMDA antagonist. The work presented in this thesis suggested that sinomenine could be explored as a novel analgesic in treating neuropathic and arthritic pain. The results also showed combination therapy involving sinomenine, gabapentin and dextromethorphan might be useful in the clinic. The potential mechanisms for the effect of sinomenine and its interaction with other analgesics need to be further studied

    Non-Excitatory Amino Acids, Melatonin, and Free Radicals: Examining the Role in Stroke and Aging

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    The aim of this review is to explore the relationship between melatonin, free radicals, and non-excitatory amino acids, and their role in stroke and aging. Melatonin has garnered significant attention in recent years due to its diverse physiological functions and potential therapeutic benefits by reducing oxidative stress, inflammation, and apoptosis. Melatonin has been found to mitigate ischemic brain damage caused by stroke. By scavenging free radicals and reducing oxidative damage, melatonin may help slow down the aging process and protect against age-related cognitive decline. Additionally, non-excitatory amino acids have been shown to possess neuroprotective properties, including antioxidant and anti-inflammatory in stroke and aging-related conditions. They can attenuate oxidative stress, modulate calcium homeostasis, and inhibit apoptosis, thereby safeguarding neurons against damage induced by stroke and aging processes. The intracellular accumulation of certain non-excitatory amino acids could promote harmful effects during hypoxia-ischemia episodes and thus, the blockade of the amino acid transporters involved in the process could be an alternative therapeutic strategy to reduce ischemic damage. On the other hand, the accumulation of free radicals, specifically mitochondrial reactive oxygen and nitrogen species, accelerates cellular senescence and contributes to age-related decline. Recent research suggests a complex interplay between melatonin, free radicals, and non-excitatory amino acids in stroke and aging. The neuroprotective actions of melatonin and non-excitatory amino acids converge on multiple pathways, including the regulation of calcium homeostasis, modulation of apoptosis, and reduction of inflammation. These mechanisms collectively contribute to the preservation of neuronal integrity and functions, making them promising targets for therapeutic interventions in stroke and age-related disorders.This work was supported by MICIU (grant number PID2021-128133NB-I00/AEI/FEDER10.13039/501100011033) to J.M.H.-G. and V.J.C. enjoys a contract from the CAM ‚ÄúInvestigo‚ÄĚ program (PIP/2022-09971). A.R. thanks UCJC (INFLAMAMEL 2022-07 project) for its continued support

    The use of novel techniques to study the roles of cytokines in joint pain and inflammation

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    Rheumatoid arthritis (RA) is a common, chronic, autoimmune, inflammatory disease characterized by persistent synovitis that results in the progressive destruction ofjoints. The cellular and molecular basis of the inflammation is complex and multifactorial. During the progression of the disease many types of cells are activated, which in turn secrete a variety of mediators, including cytokines, which initiate and perpetuate the disease.Rat adjuvant-induced unilateral arthritis is a well established RA disease model and use of this model has facilitated the understanding of the pathology of joint inflammation. The model closely mimics the pathology of human RA, including histopathological changes, cell infiltration, as well as hypersensitivity and swelling of the joint. Measurements of spontaneous pain and hypersensitivity states are assessed in this model. However, no objective measure ofjoint hypersensitivity is used to assess experimental arthritic joint pain in laboratory rodents. To that end, the pressure application device (PAD) was developed to align pre-clinical measures to those used clinically and help the translation of animal studies to human conditions. PAD was able to detect FCA-induced hypersensitivity in mice and rats, observed as a decrease in limb withdrawal thresholds (LWTs) of around 60% and 40% respectively, compared with basal levels in normal joints. PAD subsequently detected prednisolone analgesia in both species, which was abolished after dosing ceased. PAD also showed significant reversal of evoked mechanical hypersensitivity in arthritic animals treated with morphine or celecoxib, which was comparable to that measured by the weight distribution readout. PAD provides a novel, accurate behavioural tool for detecting localised primary mechanical hypersensitivity in two animal models of chronic inflammatory joint pain.The infiltration of cells and release of inflammatory proteins in the synovial tissue and joint space is a key characteristic of synovitis. Measuring the levels of these in the synovial fluid can provide information about the underlying pathophysiology of joint v disease. Furthermore changes occurring in the synovial fluid can be used as biomarkers of disease; therefore the joint perfusion method was developed to evaluate the inflammatory protein and cell content of rat knee joints, to further validate the adjuvant-induced arthritis model, as well as to determine the effects of inflammatory insults or the effect of anti¬ inflammatory, analgesic or anti-rheumatic drugs. This technique proved to be reliable and consistent when perfusing the joint cavity, and regular volumes of sample were easily collected. This technique is therefore a valuable addition to protocols which use homogenates of entire joints to assess inflammatory mediator content.The temporal expression patterns of cytokines and inflammatory cells in the knee joints of rats following induction of arthritis were determined using the novel perfusion technique. Cytokine expression altered over time as arthritis progressed from the acute to the more "chronic" phase. The proportion of inflamed joints that contained detectable levels of each mediator measured was significantly increased during the study. This suggests that it may be the presence of the protein, even at low levels, that is important for the development and maintenance of joint inflammation and hypersensitivity. In addition, significant correlations between measures ofjoint swelling or mechanical hypersensitivity and levels of cytokines in inflamed joints were seen. Prednisolone did not affect the absolute levels of cytokines in inflamed joints, although it reduced the percentage of inflamed joints that contained detectable levels of ILla and IL6. This suggests that the steroid appears to have an all-or-none effect in terms of cytokine expression levels in this study.The roles of ILip and IL6 in joint pain and inflammation were assessed. The contribution of the activity of primary afferent fibres to joint pain and hypersensitivity after administration of intra-articular ILip or IL6 was investigated by recording action potentials from primary afferent nerves innervating the knee joint. IL1 p caused a transient increase in the frequency of basal neural discharge by 88% within three hours. It also decreased the threshold of mechanical stimulation required to evoke neural activity by 50% between one and four hours after injection. In contrast, IL6 did not affect the frequency of basal neural discharge or the mechanical threshold. Neither ILiß nor IL6 affected the neural discharge frequency to mechanical stimulation above the threshold. The induction of basal neural activity resembles the occurrence of spontaneous pain during inflammation, such as that measured by the incapacitance tester as a result of intra-articular IL1ß or IL6. A reduction in the LWT, measured by PAD, following ILiß or IL6 occurred within a few hours, similar to the decrease in the mechanical threshold to von Frey hairs in primary afferents after ILiß, as a result of neuronal sensitization. Although ILiß or IL6 did not cause swelling of the joint, they did induce mechanical hypersensitivity within a couple of hours, which lasted for up to four days. Intra-articular IL1ß or IL6 had no effect on joint structure, bone or cartilage. ILiß and IL6 evoked increases in the expression of ILip, IL6 and TNFa within the first eight hours, and additionally elevated levels of ILla, IL2, IL4 (IL6-treated only) and IL10 (ILiß-treated only) from day one post administration. ILiß also resulted in recruitment of inflammatory cells into the synovial cavity one day after administration.In conclusion, this study has developed and validated two novel techniques to study experimental joint pain and inflammation in rodents; the behavioural measure of joint mechanical hypersensitivity, PAD; and the joint perfusion technique to assess inflammatory mediator and cell content of synovial fluid. These methods have been used alongside other techniques to show the temporal cytokine expression patterns during adjuvant-induced arthritis and the relationship of these to swelling and hypersensitivity of the joint. The roles of ILip and IL6 in evoking joint pain and hypersensitivity were also investigated. This data supports the hypothesis that ILip and IL6 are directly involved in the development of joint pain, but cannot alone elicit swelling or joint damage at doses sufficient to evoke hypersensitivity. Furthermore, similarities between this animal model of joint disease and human RA have been demonstrated that further validate the model as a valuable pre-clinical tool to study the inflammatory process of human RA. Moreover, consolidation of these similarities helps improve the confidence of novel drug screening using this model prior to use in the clinic

    Modificaciones de la función de la inervación perivascular en arteria mesentérica superior en distintas situaciones fisiológicas y patológicas

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    Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Fisiología. Fecha de lectura: 05-11-2015Esta Tesis ha sido realizada en el Departamento de Fisiología de la Universidad Autónoma de Madrid. Ha sido financiada por el Ministerio de Economía y Competitividad (SAF2009-10374; SAF2012-38530) y Fundación Mapfr

    Activación del complejo NLRP3-Inflamasoma como posible factor etiopatogénico de la depresión mayor

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    Programa de Doctorado en Psicolog√≠a Cl√≠nica y de la SaludEl trastorno depresivo mayor (TDM) es la enfermedad mental m√°s prevalente y un importante problema de salud en la sociedad actual. Aunque su epidemiolog√≠a, s√≠ntomas y complicaciones han sido ampliamente documentados, su etiolog√≠a y fisiopatolog√≠a permanecen a√ļn sin dilucidar. En las dos √ļltimas d√©cadas, se ha recopilado una amplia evidencia que apoya el papel de la inflamaci√≥n como posible factor etiol√≥gico de la depresi√≥n mayor. Adem√°s, se ha mostrado repetidamente que los niveles de citoquinas pro-inflamatorias est√°n elevados en personas diagnosticadas de TDM, entre ellas, las citoquinas IL-1√ü e IL-18. Sin embargo, los mecanismos por los cuales se producen estos procesos inflamatorios a√ļn no est√°n claros. En los √ļltimos a√Īos, las IL-1√ü e IL-18 han adquirido mucha relevancia por su implicaci√≥n en diversas patolog√≠as y su relaci√≥n con algunas caspasas implicadas en la inflamaci√≥n y la apoptosis, como es el caso de la caspasa-1. Precisamente las IL-1√ü e IL-18, son las principales citoquinas activadas por un nuevo sistema inflamatorio conocido como complejo NLRP3-Inflamasoma, un complejo prot√©ico considerado como un sensor de estr√©s intracelular, cuya activaci√≥n es responsable de la inflamaci√≥n sist√©mica. En este sentido, en el presente estudio hemos investigado la posible implicaci√≥n del complejo NLRP3-Inflamasoma (inflamasoma) en la fisiopatolog√≠a del TDM, examinado un aspecto novedoso en relaci√≥n a los procesos de inmuno-inflamaci√≥n en la respuesta de estr√©s y la depresi√≥n, y es el hecho de que el complejo NLRP3-Inflamasoma pueda constituir un puente entre el estr√©s psicol√≥gico y la depresi√≥n. Adem√°s, hemos analizado la posibilidad de que la modulaci√≥n de este complejo pueda convertirse en un objetivo clave en el tratamiento de este trastorno, as√≠ como en un biomarcador para evaluar la respuesta al tratamiento antidepresivo en pacientes con TDM. Para ello, hemos trabajado en primer lugar con una muestra de pacientes con TDM tratados y no tratados con el antidepresivo amitriptilina. Los resultados han mostrado que el complejo NLRP3-Inflamasoma se encuentra activado en pacientes con TDM, puesto de manifiesto por niveles elevados de la expresi√≥n de prote√≠na y ARNm de NLRP3 y Caspasa-1 en c√©lulas mononuclares de la sangre de los pacientes y por niveles s√©ricos elevados de IL-1√ü e IL-18. Adem√°s, hemos encontrado que los niveles de estas citoquinas correlacionan positivamente con los s√≠ntomas depresivos, medidos mediante el Inventario de Depresi√≥n de Beck (BDI). Los niveles de estr√©s oxidativo tambi√©n se han encontrado elevados en estos pacientes. El tratamiento con amitriptilina redujo la activaci√≥n del inflamasoma en los pacientes, pero no los niveles de estr√©s oxidativo, llev√°ndonos a pensar que ten√≠a que existir una v√≠a alternativa para la activaci√≥n de este complejo en el TDM que quiz√°s podr√≠a ser el estr√©s psicol√≥gico. En este sentido, en una segunda parte de nuestro estudio, hemos trabajado con un modelo animal (rat√≥n) de depresi√≥n inducida por estr√©s, y los resultados han mostrado que NLRP3-Inflamasoma est√° implicado en la depresi√≥n producida como consecuencia del estr√©s cr√≥nico. Nuestro trabajo ha mostrado que en ausencia de NLRP3 inflamasoma, el estr√©s prolongado no provoca comportamientos depresivos, ni activaci√≥n microglial, ni disminuci√≥n de la neurog√©nesis del hipocampo. En una tercera parte de nuestro estudio, hemos evaluado el efecto que ciertos f√°rmacos antidepresivos, utilizados normalmente en la pr√°ctica cl√≠nica, tienen en la modulaci√≥n de la activaci√≥n del inflamasoma, tanto en un modelo invitro de c√©lulas THP-1 estimuladas por ATP, como en un modelo de rat√≥n de depresi√≥n inducida por estr√©s, como en una muestra de pacientes con TDM. Los resultados han mostrado que los antidepresivos produc√≠an una reducci√≥n de la activaci√≥n del inflamasoma manifestada a trav√©s de una disminuci√≥n de la expresi√≥n prot√©ica y de ARNm de NLRP3 y de IL-1√ü (p17), y de una disminuci√≥n de los niveles s√©ricos de IL-1√ü y IL-18. Adem√°s, se ha observado una interesante correlaci√≥n negativa entre los niveles de IL-1√ü y los niveles de serotonina en los pacientes tratados. Estos resultados proporcionan una nueva comprensi√≥n de la patog√©nesis del TDM y se√Īalan al inflamasoma como un posible objetivo para nuevas intervenciones terap√©uticas para esta enfermedad.Universidad Pablo de Olavide. Departamento de Fisiolog√≠a, Anatom√≠a y Biolog√≠a Celula
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