Uraemic toxins impair skeletal muscle regeneration by inhibiting myoblast proliferation, reducing myogenic differentiation, and promoting muscular fibrosis

17 p.Uraemic toxins increase in serum parallel to a decline in the glomerular filtration rate and the development of sarcopenia in patients with chronic kidney disease (CKD). This study analyses the role of uraemic toxins in sarcopenia at different stages of CKD, evaluating changes in the muscular regeneration process. Cultured C2C12 cells were incubated with a combination of indoxyl sulphate and p-cresol at high doses (100 mu g/mL) or low doses (25 mu g/mL and 10 mu g/mL) resembling late or early CKD stages, respectively. Cell proliferation (analysed by scratch assays and flow cytometry) was inhibited only by high doses of uraemic toxins, which inactivated the cdc2-cyclin B complex, inhibiting mitosis and inducing apoptosis (analysed by annexin V staining). By contrast, low doses of uraemic toxins did not affect proliferation, but reduced myogenic differentiation, primed with 2% horse serum, by inhibiting myogenin expression and promoting fibro-adipogenic differentiation. Finally, to assess the in vivo relevance of these results, studies were performed in gastrocnemii from uraemic rats, which showed higher collagen expression and lower myosin heavy chain expression than those from healthy rats. In conclusion, uraemic toxins impair the skeletal muscular regeneration process, even at low concentrations, suggesting that sarcopenia can progress from the early stages of CKD.Instituto de Salud Carlos II

Endothelin-1 induces cellular senescence and fibrosis in cultured myoblasts. A potential mechanism of aging-related sarcopenia

Endothelial dysfunction, with increased endothelin-1 (ET-1) synthesis, and sarcopenia, characterized by the loss of muscular mass and strength, are two aging-related conditions. However, a relationship between them has not been already established. The aim of this study was to determine whether ET-1 induces senescence and fibrosis in cultured murine myoblasts, which could be involved in the development of sarcopenia related to aging. For this purpose, myoblasts were incubated with ET-1 to assess cellular senescence, analyzed by senescence associated beta-galactosidase activity and p16 expression; and fibrosis, assessed by fibronectin expression. ET-1 induced myoblast senescence and fibrosis through ETA receptor. The use of antioxidants and several antagonists revealed that ET-1 effect on senescence and fibrosis depended on ROS production and activation of PI3K-AKT-GSK pathway. To stress the in vivo relevance of these results, circulating ET-1, muscular strength, muscular fibrosis and p16 expression were measured in male C57Bl6 mice from 5-18-24-months-old. Old mice shown high levels of ET-1 correlated with muscular fibrosis, muscular p16 expression and loss of muscle strength. In conclusion, ET-1 promotes fibrosis and senescence in cultured myoblasts, similar results were found in old mice, suggesting a potential role for ET-1 in the development of sarcopenia related to aging

Aging-related hyperphosphatemia impairs myogenic differentiation and enhances fibrosis in skeletal muscle

14 p.Background Hyperphosphatemia has been related to the development of sarcopenia in aging mice. We describe the intracellular mechanisms involved in the impairment of the myogenic differentiation promoted by hyperphosphatemia and analyse these mechanisms in the muscle from older mice. Methods C2C12 cells were grown in 2% horse serum in order to promote myogenic differentiation, in the presence or absence of 10 mM beta-glycerophosphate (BGP) for 7 days. Troponin T, paired box 7 (Pax-7), myogenic factor 5 (Myf5), myogenic differentiation 1 (MyoD), myogenin (MyoG), myocyte enhancer factor 2 (MEF2C), P300/CBP-associated factor (PCAF), histone deacetylase 1 (HDAC1), fibronectin, vimentin, and collagen I were analysed at 48, 72, and 168 h, by western blotting or by immunofluorescence staining visualized by confocal microscopy. Studies in mice were performed in 5- and 24-month-old C57BL6 mice. Three months before sacrifice, 21-month-old mice were fed with a standard diet or a low phosphate diet, containing 0.6% or 0.2% phosphate, respectively. Serum phosphate concentration was assessed by a colorimetric method and forelimb strength by a grip test. Fibrosis was observed in the tibialis anterior muscle by Sirius Red staining. In gastrocnemius muscle, MyoG, MEF2C, and fibronectin expressions were analysed by western blotting. Results Cells differentiated in the presence of BGP showed near five times less expression of troponin T and kept higher levels of Pax-7 than control cells indicating a reduced myogenic differentiation. BGP reduced Myf5 about 50% and diminished MyoD transcriptional activity by increasing the expression of HDAC1 and reducing the expression of PCAF. Consequently, BGP reduced to 50% the expression of MyoG and MEF2C. A significant increase in the expression of fibrosis markers as collagen I, vimentin, and fibronectin was found in cells treated with BGP. In mice, serum phosphate (17.24 ± 0.77 mg/dL young; 23.23 ± 0.81 mg/dL old; 19.09 ± 0.75 mg/dL old with low phosphate diet) correlates negatively (r = 0.515, P = 0.001) with the muscular strength (3.13 ± 0.07 gf/g young; 1.70 ± 0.12 gf/ g old; 2.10 ± 0.09 gf/g old with low phosphate diet) and with the expression of MyoG (r = 0.535, P = 0.007) and positively with the expression of fibronectin (r = 0.503, P = 0.001) in gastrocnemius muscle. The tibialis anterior muscle from old mice showed muscular fibrosis. Older mice fed with a low phosphate diet showed improved muscular parameters relative to control mice of similar age. Conclusions Hyperphosphatemia impairs myogenic differentiation, by inhibiting the transcriptional activity of MyoD, and enhances the expression of fibrotic genes in cultured myoblasts. Experiments carried out in older mice demonstrate a close relationship between age-related hyperphosphatemia and the decrease in the expression of myogenic factors and the increase in factors related to muscle fibrosis.Instituto de Salud Carlos IIIPrincipado de AsturiasComunidad de Madri

Hyperphosphatemia-Induced Oxidant/Antioxidant Imbalance Impairs Vascular Relaxation and Induces Inflammation and Fibrosis in Old Mice

Aging impairs vascular function, but the mechanisms involved are unknown. The aim of this study was to analyze whether aging-related hyperphosphatemia is implied in this effect by elucidating the role of oxidative stress. C57BL6 mice that were aged 5 months (young) and 24 months (old), receiving a standard (0.6%) or low-phosphate (0.2%) diet, were used. Isolated mesenteric arteries from old mice showed diminished endothelium-dependent vascular relaxation by the down-regulation of NOS3 expression, increased inflammation and increased fibrosis in isolated aortas, compared to those isolated from young mice. In parallel, increased Nox4 expression and reduced Nrf2, Sod2-Mn and Gpx1 were found in the aortas from old mice, resulting in oxidant/antioxidant imbalance. The low-phosphate diet improved vascular function and oxidant/antioxidant balance in old mice. Mechanisms were analyzed in endothelial (EC) and vascular smooth muscle cells (SMCs) treated with the phosphate donor ss-glycerophosphate (BGP). In EC, BGP increased Nox4 expression and ROS production, which reduced NOS3 expression via NF kappa B. BGP also increased inflammation in EC. In SMC, BGP increased Collagen I and fibronectin expression by priming ROS production and NF kappa B activity. In conclusion, hyperphosphatemia reduced endothelium-dependent vascular relaxation and increased inflammation and vascular fibrosis through an impairment of oxidant/antioxidant balance in old mice. A low-phosphate diet achieved improvements in the vascular function in old mice

Hyperphosphatemia Promotes Senescence of Myoblasts by Impairing Autophagy Through Ilk Overexpression, A Possible Mechanism Involved in Sarcopenia

In mammalians, advancing age is associated with sarcopenia, the progressive and involuntary loss of muscle mass and strength. Hyperphosphatemia is an aging-related condition involved in several pathologies. The aim of this work was to assess whether hyperphosphatemia plays a role in the age-related loss of mass muscle and strength by inducing cellular senescence in murine myoblasts and to explore the intracellular mechanism involved in this effect. Cultured mouse C2C12 cells were treated with 10 mM beta-glycerophosphate (BGP] at different periods of time to induce hyperphosphatemia. BGP promoted cellular senescence after 24 h of treatment, assessed by the increased expression of p53, acetylated-p53 and p21 and senescence associated beta-galactosidase activity. In parallel, BGP increased ILK expression and activity, followed by mTOR activation and autophagy reduction. Knocking-down ILK expression increased autophagy and protected cells from senescence induced by hyperphosphatemia. BGP also reduced the proliferative capacity of cultured myoblasts. Old mice (24months-old] presented higher serum phosphate concentration, lower forelimb strength, higher expression of p53 and ILK and less autophagy in vastus muscle than young mice (5-months-old]. In conclusion, we propose that hyperphosphatemia induces senescence in cultured myoblasts through ILK overexpression, reducing their proliferative capacity, which could be a mechanism involved in the development of sarcopenia, since old mice showed loss of muscular strength correlated with high serum phosphate concentration and increased levels of ILK and p53

Vitamin D treatment prevents uremia-induced reductions in aortic microRNA-145 attenuating osteogenic differentiation despite hyperphosphatemia

In chronic kidney disease, systemic inflammation and high serum phosphate (P) promote the de-differentiation of vascular smooth muscle cells (VSMC) to osteoblast-like cells, increasing the propensity for medial calcification and cardiovascular mortality. Vascular microRNA-145 (miR-145) content is essential to maintain VSMC contractile phenotype. Because vitamin D induces aortic miR-145, uremia and high serum P reduce it and miR-145 directly targets osteogenic osterix in osteoblasts, this study evaluated a potential causal link between vascular miR-145 reductions and osterix-driven osteogenic differentiation and its counter-regulation by vitamin D. Studies in aortic rings from normal rats and in the rat aortic VSMC line A7r5 exposed to calcifying conditions corroborated that miR-145 reductions were associated with decreases in contractile markers and increases in osteogenic differentiation and calcium (Ca) deposition. Furthermore, miR-145 silencing enhanced Ca deposition in A7r5 cells exposed to calcifying conditions, while miR-145 overexpression attenuated it, partly through increasing α-actin levels and reducing osterix-driven osteogenic differentiation. In mice, 14 weeks after the induction of renal mass reduction, both aortic miR-145 and α-actin mRNA decreased by 80% without significant elevations in osterix or Ca deposition. Vitamin D treatment from week 8 to 14 fully prevented the reductions in aortic miR-145 and attenuated by 50% the decreases in α-actin, despite uremia-induced hyperphosphatemia. In conclusion, vitamin D was able to prevent the reductions in aortic miR-145 and α-actin content induced by uremia, reducing the alterations in vascular contractility and osteogenic differentiation despite hyperphosphatemia

Caracterización de la investigación, el desarrollo tecnológico y la innovación en el sector productivo de la región fronteriza colombo venezolana

En el libro se presenta la recopilación de proyectos de Investigación e Innovación tecnológica como resultado del desarrollo de actividades investigativas, donde se involucran grupos de investigación y semilleros, instructores investigadores, docentes universitarios, administrativos, aprendices, estudiantes universitarios y empresarios del ámbito regional, nacional e internacional, quienes motivados por su espíritu emprendedor e innovador le apostaron a involucrarse en proyectos desde las áreas de automatización, electrónica y telecomunicaciones, gestión de hábitat , Diseño e implementación de soluciones en TIC, Gestión del negocio emprendimiento y empresarismo, innovación educativa y diseño de vestuario.The book presents the compilation of Research and Technological Innovation projects as a result of the development of research activities, where research groups and seedbeds, research instructors, university teachers, administrative staff, apprentices, university students and entrepreneurs from the regional, national level are involved. and international, who, motivated by his entrepreneurial and innovative spirit, bet him to get involved in projects from the areas of automation, electronics and telecommunications, habitat management, Design and implementation of ICT solutions, Business management, entrepreneurship and entrepreneurship, educational innovation and design. wardrobe.Caracterización de la investigación, el desarrollo tecnológico y la innovación en el sector productivo de la región fronteriza colombo venezolana -- Modelo de un sistema hidráulico controlado por redes neuronales – Sistema de gestión y monitoreo de consumo de servicios domiciliarios fomentando la “sostenibilidad inductiva” -- Cálculo de los parámetros hidráulicos y mecánicos de un prototipo robótico para la fumigación de cultivos de media y baja altura -- Manipulador robótico en el sistema integrado por computadora plataforma Cim-C -- Planificación multinivel y conflictos generados por la transformación de los espacios agrarios en el sector periurbano fronterizo de los trapiches, villa del rosario. -- Herramienta tecnológica para la vinculación del aprendiz sena del programa de articulación media con el sector productivo de la ciudad de bucaramanga -- Global kids máquina de intercambio financiero Global Kids financial Exchange machine – Desarrollo de aplicación móvil para la enseñanza e instrucción del área de documentación y gestión administrativa -- Diseño de una aplicación informática on-line para optimizar la gestión de los procesos, tramites e informes de los materiales de formación del sena centro cies regional norte de santander -- creación sala hub de consultoría estratégica mipymes norte de santander -- Diseño recorrido virtual de gestión documental Regional Norte de Santander: SENA -- Factores de riesgo provocadas por el incremento de estrés en las empresas industriales mexicanas -- Logística de la comercialización del plátano procedente de los municipios buenavista, córdoba y pijao -- Sistema de información móvil integrador de procesos formativos del sena con la comunidad educativa -- Sistematización de la información contable y financiera de los proyectos de aula en la media técnica -- BANKIDS juego didáctico y financiero -- Causas que originan la mala ortografía en los aprendices de la red de gestión administrativa y servicios financieros -- Informe sobre la deserción de aprendices de gestión administrativa y servicios financieros -- uso de las ntic desde el semillero de investigación e innovación virtual e-innovacmm centro metalmecánicona207 página