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Amyotrophic lateral sclerosis (ALS) is a fatal motoneuron degenerative disease that is associated with demyelination. The Wobbler (WR) mouse exhibits motoneuron degeneration, gliosis and myelin deterioration in the cervical spinal cord. Since male WRs display low testosterone (T) levels in the nervous system, we investigated if T modified myelin-relative parameters in WRs in the absence or presence of the aromatase inhibitor, anastrozole (A). We studied myelin by using luxol-fast-blue (LFB) staining, semithin sections, electron microscopy and myelin protein expression, density of IBA1+ microglia and mRNA expression of inflammatory factors, and the glutamatergic parameters glutamine synthetase (GS) and the transporter GLT1. Controls and WR + T showed higher LFB, MBP and PLP staining, lower g-ratios and compact myelin than WRs and WR + T + A, and groups showing the rupture of myelin lamellae. WRs showed increased IBA1+ cells and mRNA for CD11b and inflammatory factors (IL-18, TLR4, TNFαR1 and P2Y12R) vs. controls or WR + T. IBA1+ cells, and CD11b were not reduced in WR + T + A, but inflammatory factors' mRNA remained low. A reduction of GS+ cells and GLT-1 immunoreactivity was observed in WRs and WR + T + A vs. controls and WR + T. Clinically, WR + T but not WR + T + A showed enhanced muscle mass, grip strength and reduced paw abnormalities. Therefore, T effects involve myelin protection, a finding of potential clinical translation.

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Con motivo del Día Mundial de la Ciencia y la Tecnología, se realizó en la Casa Museo Bernardo Houssay un conversatorio en el que expertos biógrafos resaltaron algunos aspectos de la trayectoria profesional del Premio Nobel de Medicina de 1947, destacando su actividad como investigador en fisiología y sus cualidades humanas. Estos importantes estudiosos del tema compartieron sus conocimientos en un selecto auditorio. (AU)

On the occasion of World Science and Technology Day, a discussion was held at the Bernardo Houssay House Museum in which expert biographers highlighted some aspects of the professional career of the 1947 Nobel Prize in Medicine, highlighting his activity as a researcher in physiology and his human qualities. These important scholars of the subject shared their knowledge in a select audience. (AU)

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There is growing evidence indicating that mineralocorticoid receptor (MR) expression influences a wide variety of functions in metabolic and immune response. The present study explored if antagonism of the MR reduces neuroinflammation in the spinal cord of mice with experimental autoimmune encephalomyelitis (EAE). Eplerenone (EPLE) (100 mg/kg dissolved in 30% 2-hydroxypropyl-ß-cyclodextrin) was administered intraperitoneally (i.p.) daily from EAE induction (day 0) until sacrificed on day 17 post-induction. The MR blocker (a) significantly decreased the inflammatory parameters TLR4, MYD88, IL-1ß, and iNOS mRNAs; (b) attenuated HMGB1, NLRP3, TGF-ß mRNAs, microglia, and aquaporin4 immunoreaction without modifying GFAP. Serum IL-1ß was also decreased in the EAE+EPLE group. Moreover, EPLE treatment prevented demyelination and improved clinical signs of EAE mice. Interestingly, MR was decreased and GR remained unchanged in EAE mice while EPLE treatment restored MR expression, suggesting that a dysbalanced MR/GR was associated with the development of neuroinflammation. Our results indicated that MR blockage with EPLE attenuated inflammation-related spinal cord pathology in the EAE mouse model of Multiple Sclerosis, supporting a novel therapeutic approach for immune-related diseases.

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Glucocorticoids exert antiinflammatory, antiproliferative and immunosupressive effects. Paradoxically they may also enhance inflammation particularly in the nervous system, as shown in Cushing´ syndrome and neurodegenerative disorders of humans and models of human diseases. ."The Wobbler mouse model of amyotrophic lateral sclerosis shows hypercorticoidism and neuroinflammation which subsided by treatment with the glucocorticoid receptor (GR) modulator Dazucorilant (CORT113176). This effect suggests that GR mediates the chronic glucocorticoid unwanted effects. We now tested this hypothesis using a chronic stress model resembling the condition of the Wobbler mouse Male NFR/NFR mice remained as controls or were subjected to a restraining / rotation stress protocol for 3 weeks, with a group of stressed mice receiving CORT113176 also for 3 weeks. We determined the mRNAS or reactive protein for the proinflamatory factors HMGB1, TLR4, NFkB, TNFα, markers of astrogliosis (GFAP, SOX9 and acquaporin 4), of microgliosis (Iba, CD11b, P2RY12 purinergic receptor) as well as serum IL1ß and corticosterone. We showed that chronic stress produced high levels of serum corticosterone and IL1ß, decreased body and spleen weight, produced microgliosis and astrogliosis and increased proinflammatory mediators. In stressed mice, modulation of the GR with CORT113176 reduced Iba + microgliosis, CD11b and P2RY12 mRNAs, immunoreactive HMGB1 + cells, GFAP + astrogliosis, SOX9 and acquaporin expression and TLR4 and NFkB mRNAs vs. stress-only mice. The effects of CORT113176 indicate that glucocorticoids are probably involved in neuroinflammation. Thus, modulation of the GR would become useful to dampen the inflammatory component of neurodegenerative disorders.

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INTRODUCTION/AIMS: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a higher incidence in men suggesting an influence of sex steroids. Our objective was to investigate past exposure to endogenous and synthetic steroids in female ALS patients and controls. METHODS: We administered a questionnaire to 158 postmenopausal women (75 ALS patients and 83 controls). We calculated reproductive time span (RTS), lifetime endogenous estrogen (LEE) and progesterone exposures (LPE), oral contraceptive pill (OCP) use, and reproductive history. RESULTS: ALS patients showed shorter LEE and LPE, a lower proportion of breast cancer, and 11% showed no history of pregnancies vs. 4% of controls. Odds ratios (ORs) showed that <17 y of LEE and a delayed menarche (>13 y) constitute risk factors for ALS [OR = 2.1 (95% confidence interval {CI}, 1.08-4.2); and OR = 2.4 (95% CI, 1.1-5.1) respectively]. According to Cox survival analysis, for each year the LEE increased over 17 y, it was independently associated with longer survival [hazard ratio (HR) = 0.37 (95% CI, 0.16-0.85)] after adjusting for smoking, age and site of onset. Multivariate regression analysis demonstrated that for each month using OCP for longer than 40 mo increased the risk of ALS [adjusted OR = 4.1 (95% CI, 1.2-13.8)]. DISCUSSION: Thus, longer exposure to endogenous female sex steroids increased survival and reduced ALS susceptibility. In contrast, longer exposure to synthetic sex steroids showed a negative impact by reducing the production of endogenous female sex steroids or due to crossover with other steroid receptors. Given the neuroprotective effects of sex steroids, we suggest that abnormalities of neuroendocrine components may alter motor function in women with ALS.

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Hippocampal neuropathology is a recognized feature of the spontaneously hypertensive rat (SHR). The hippocampal alterations associate with cognitive impairment. We have shown that hippocampal abnormalities are reversed by 17ß-estradiol, a steroid binding to intracellular receptors (estrogen receptor α and ß subtypes) or the membrane-located G-protein coupled estradiol receptor. Genistein (GEN) is a neuroprotective phytoestrogen which binds to estrogen receptor ß and G-protein coupled estradiol receptor. Here, we investigated whether GEN neuroprotection extends to SHR. For this purpose, we treated 5-month-old SHR for 2 weeks with 10 mg kg-1 daily s.c injections of GEN. We analyzed the expression of doublecortin+ neuronal progenitors, glial fibrillary acidic protein+ astrocytes and ionized calcium-binding adapter molecule 1+ microglia in the CA1 region and dentate gyrus of the hippocampus using immunocytochemistry, whereas a quantitative real-time polymerase chain reaction was used to measure the expression of pro- and anti-inflammatory factors tumor necrosis factor α, cyclooxygenase-2 and transforming growth factor ß. We also evaluated hippocampal dependent memory using the novel object recognition test. The results showed a decreased number of doublecortin+ neural progenitors in the dentate gyrus of SHR that was reversed with GEN. The number of glial fibrillary acidic protein+ astrocytes in the dentate gyrus and CA1 was increased in SHR but significantly decreased by GEN treatment. Additionally, GEN shifted microglial morphology from the predominantly activated phenotype present in SHR, to the more surveillance phenotype found in normotensive rats. Furthermore, treatment with GEN decreased the mRNA of the pro-inflammatory factors tumor necrosis factor α and cyclooxygenase-2 and increased the mRNA of the anti-inflammatory factor transforming growth factor ß. Discrimination index in the novel object recognition test was decreased in SHR and treatment with GEN increased this parameter. Our results indicate important neuroprotective effects of GEN at the neurochemical and behavioral level in SHR. Our data open an interesting possibility for proposing this phytoestrogen as an alternative therapy in hypertensive encephalopathy.

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The Wobbler mouse is an accepted model of sporadic amyotrophic lateral sclerosis. The spinal cord of clinically symptomatic animals (3-5 months old) shows vacuolar motoneuron degeneration, inflammation, and gliosis accompanied by motor impairment. However, data are not conclusive concerning pathological changes appearing early after birth. To answer this question, we used postnatal day (PND) 6 genotyped Wobbler pups to determine abnormalities of glia and neurons at this early age period in the spinal cord. We found astrogliosis, microgliosis with morphophenotypic changes pointing to active ameboid microglia, enhanced expression of the proinflammatory markers TLR4, NFkB, TNF, and inducible nitric oxide synthase. The astrocytic enzyme glutamine synthase and the glutamate-aspartate transporter GLAST were also reduced in PND 6 Wobbler pups, suggesting excitotoxicity due to impaired glutamate homeostasis. At the neuronal level, PND 6 Wobblers showed swollen soma, increased choline acetyltransferase immunofluorescence staining, and low expression of the neuronal nuclear antigen NeuN. However, vacuolated motoneurons, a typical signature of older clinically symptomatic Wobbler mice, were absent in the spinal cord of PND 6 Wobblers. The results suggest predominance of neuroinflammation and abnormalities of microglia and astrocytes at this early period of Wobbler life, accompanied by some neuronal changes. Data support the non-cell autonomous hypothesis of the Wobbler disorder, and bring useful information with regard to intervening molecular inflammatory mechanisms at the beginning stage of human motoneuron degenerative diseases.

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Progesterone regulates a number of processes in neurons and glial cells not directly involved in reproduction or sex behavior. Several neuroprotective effects are better observed under pathological conditions, as shown in the Wobbler mouse model of amyotrophic laterals sclerosis (ALS). Wobbler mice are characterized by forelimb atrophy due to motoneuron degeneration in the spinal cord, and include microgliosis and astrogliosis. Here we summarized current evidence on progesterone reversal of Wobbler neuropathology. We demonstrated that progesterone decreased motoneuron vacuolization with preservation of mitochondrial respiratory complex I activity, decreased mitochondrial expression and activity of nitric oxide synthase, increased Mn-dependent superoxide dismutase, stimulated brain-derived neurotrophic factor, increased the cholinergic phenotype of motoneurons, and enhanced survival with a concomitant decrease of death-related pathways. Progesterone also showed differential effects on glial cells, including increased oligodendrocyte density and downregulation of astrogliosis and microgliosis. These changes associate with reduced anti-inflammatory markers. The enhanced neurochemical parameters were accompanied by longer survival and increased muscle strength in tests of motor behavior. Because progesterone is locally metabolized to allopregnanolone (ALLO) in nervous tissues, we also studied neuroprotection by this derivative. Treatment of Wobbler mice with ALLO decreased oxidative stress and glial pathology, increased motoneuron viability and clinical outcome in a progesterone-like manner, suggesting that ALLO could mediate some progesterone effects in the spinal cord. In conclusion, the beneficial effects observed in different parameters support the versatile properties of progesterone and ALLO in a mouse model of motoneuron degeneration. The studies foresee future therapeutic opportunities with neuroactive steroids for deadly diseases like ALS.

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The hippocampus encodes spatial and contextual information involved in memory and learning. The incorporation of new neurons into hippocampal networks increases neuroplasticity and enhances hippocampal-dependent learning performances. Only few studies have described hippocampal abnormalities after spinal cord injury (SCI) although cognitive deficits related to hippocampal function have been reported in rodents and even humans. The aim of this study was to characterize in further detail hippocampal changes in the acute and chronic SCI. Our data suggested that neurogenesis reduction in the acute phase after SCI could be due to enhanced death of amplifying neural progenitors (ANPs). In addition, astrocytes became reactive and microglial cells increased their number in almost all hippocampal regions studied. Glial changes resulted in a non-inflammatory response as the mRNAs of the major pro-inflammatory cytokines (IL-1ß, TNFα, IL-18) remained unaltered, but CD200R mRNA levels were downregulated. Long-term after SCI, astrocytes remained reactive but on the other hand, microglial cell density decreased. Also, glial cells induced a neuroinflammatory environment with the upregulation of IL-1ß, TNFα and IL-18 mRNA expression and the decrease of CD200R mRNA. Neurogenesis reduction may be ascribed at later time points to inactivation of neural stem cells (NSCs) and inhibition of ANP proliferation. The number of granular cells and CA1 pyramidal neurons decreased only in the chronic phase. The release of pro-inflammatory cytokines at the chronic phase might involve neurogenesis reduction and neurodegeneration of hippocampal neurons. Therefore, SCI led to hippocampal changes that could be implicated in cognitive deficits observed in rodents and humans.

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Multiple sclerosis (MS) is an immune-mediated and degenerating disease in which myelin sheaths are damaged as a result of chronic progressive inflammation of the central nervous system. Tibolone [(7α,17α)-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-in-3-one], a synthetic estrogenic compound with tissue-specific actions and used for menopausal hormone therapy, shows neuroprotective and antioxidant properties both in vivo and in vitro. In the present study, we analyzed whether tibolone plays a therapeutic role in experimental autoimmune encephalomyelitis (EAE) mice, a commonly used model of MS. Female C57BL/6 mice were induced with the myelin oligodendrocyte glycoprotein MOG35-55 and received s.c. tibolone (0.08 mg kg-1 ) injection every other day from the day of induction until death on the acute phase of the disease. Reactive gliosis, Toll like receptor 4 (TLR4), high mobility group box protein 1 (HMGB1), inflammasome parameters, activated Akt levels and myelin were assessed by a real-time polymerase chain reaction, immunohistochemistry, and western blot analysis. Our findings indicated that, in the EAE spinal cord, tibolone reversed the astrocytic and microglial reaction, and reduced the hyperexpression of TLR4 and HMGB1, as well as NLR family pyrin domain containing 3-caspase 1-interleukin-1ß inflammasome activation. At the same time, tibolone attenuated the Akt/nuclear factor kappa B pathway and limited the white matter demyelination area. Estrogen receptor expression was unaltered with tibolone treatment. Clinically, tibolone improved neurological symptoms without uterine compromise. Overall, our data suggest that tibolone may serve as a promising agent for the attenuation of MS-related inflammation.

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