Silvia Claros

Human Phyisiology
University of Málaga


Physiology, Aging, Cell Biology


Scopus Publications

Scopus Publications

  • New molecular mechanisms to explain the neuroprotective effects of insulin-like growth factor II in a cellular model of Parkinson's disease
    Silvana-Yanina Romero-Zerbo, Nadia Valverde, Silvia Claros, Pablo Zamorano-Gonzalez, Federica Boraldi, Francesco-Demetrio Lofaro, Estrella Lara, Jose Pavia, Maria Garcia-Fernandez, Belen Gago,et al.

    Elsevier BV

  • Teaching the physiology of the human body in non-formal spaces: pilot experience of a Service-Learning methodology and the interaction between students of different educational levels
    Laura García-Durán, Silvia Claros, Pablo Zamorano-González, Marta González-García, Laura Carrillo-Franco, Marina Ponce-Velasco, Belén Gago, María García-Fernández, Manuel Víctor López-González, and Ana Aiastui

    Frontiers Media SA
    Research institutes and universities have strengthened the development of biomedicine outreach activities, constituing a non-formal education system of science literacy, although with little commitment from undergraduate students. However, as a Service-Learning methodology, these outreach activities could work as a tool for the acquisition of skills by students of Health Science Degrees. Described here is the development of the workshop entitled “Exploring the human body” at the Biodonostia Health Research Institute and the pilot experience of its implementation as a Service-Learning activity at the University of Málaga. Firstly, 359 secondary education students were mentored by Ph.D. students through a 5-station workshop with experiments and activities related to the physiology of the human body. Then, 301 undergraduate students of Medicine and Nursing Degrees advised 965 secondary education students. Both groups of students assessed the workshop via questionnaires and a debriefing. The data showed an overall score of 4.6 out of 5 for the workshop. Undergraduate students reported a positive impact on their academic background (4.8 out of 5), mainly due to the improvement of oral communication skills (34%). Therefore, this methodology could be a valid and applicable tool to develop the cross-disciplinary competences of undergraduate students.

  • Insulin-like growth factor II prevents MPP+ and glucocorticoid mitochondrial-oxidative and neuronal damage in dopaminergic neurons
    Silvia Claros, Pablo Cabrera, Nadia Valverde, Silvana Y. Romero-Zerbo, Manuel Víctor López-González, Kirill Shumilov, Alicia Rivera, Jose Pavia, Elisa Martín-Montañez, and María Garcia-Fernandez

    Stress seems to contribute to Parkinson’s disease (PD) neuropathology, probably by dysregulation of the hypothalamic–pituitary–adrenal axis. Key factors in this pathophysiology are oxidative stress and mitochondrial dysfunction and neuronal glucocorticoid-induced toxicity. The insulin-like growth factor II (IGF-II), a pleiotropic hormone, has shown antioxidant and neuroprotective effects in some neurodegenerative disorders. Our aim was to examine the protective effect of IGF-II on a dopaminergic cellular combined model of PD and mild to moderate stress measuring oxidative stress parameters, mitochondrial and neuronal markers, and signalling pathways. IGF-II counteracts the mitochondrial-oxidative damage produced by the toxic synergistic effect of corticosterone and 1-methyl-4-phenylpyridinium, protecting dopaminergic neurons from death and neurodegeneration. IGF-II promotes PKC activation and nuclear factor (erythroid-derived 2)-like 2 antioxidant response in a glucocorticoid receptor-dependent pathway, preventing oxidative cell damage and maintaining mitochondrial function. Thus, IGF-II is a potential therapeutic tool for treatment and prevention of disease progression in PD patients suffering mild to moderate emotional stress.

  • Impact of glucocorticoid on a cellular model of parkinson’s disease: Oxidative stress and mitochondrial function
    Silvia Claros, Antonio Gil, Mauro Martinelli, Nadia Valverde, Estrella Lara, Federica Boraldi, Jose Pavia, Elisa Martín-Montañez, and María Garcia-Fernandez

    Stress seems to contribute to the neuropathology of Parkinson’s disease (PD), possibly by dysregulation of the hypothalamic–pituitary–adrenal axis. Oxidative distress and mitochondrial dysfunction are key factors involved in the pathophysiology of PD and neuronal glucocorticoid-induced toxicity. Animal PD models have been generated to study the effects of hormonal stress, but no in vitro model has yet been developed. Our aim was to examine the impact of corticosterone (CORT) administration on a dopaminergic neuronal cell model of PD induced by the neurotoxin MPP+, as a new combined PD model based on the marker of endocrine response to stress, CORT, and oxidative-mitochondrial damage. We determined the impact of CORT, MPP+ and their co-incubation on reactive oxygen species production (O2−•), oxidative stress cellular markers (advanced-oxidation protein products and total antioxidant status), mitochondrial function (mitochondrial membrane potential and mitochondrial oxygen consumption rate) and neurodegeneration (Fluoro-Jade staining). Accordingly, the administration of MPP+ or CORT individually led to cell damage compared to controls (p < 0.05), as determined by several methods, whereas their co-incubation produced strong cell damage (p < 0.05). The combined model described here could be appropriate for investigating neuropathological hallmarks and for evaluating potential new therapeutic tools for PD patients suffering mild to moderate emotional stress.

  • Neuronal metabolism and neuroprotection: Neuroprotective effect of fingolimod on menadione-induced mitochondrial damage
    Antonio Gil, Elisa Martín-Montañez, Nadia Valverde, Estrella Lara, Federica Boraldi, Silvia Claros, Silvana-Yanina Romero-Zerbo, Oscar Fernández, Jose Pavia, and Maria Garcia-Fernandez

    Imbalance in the oxidative status in neurons, along with mitochondrial damage, are common characteristics in some neurodegenerative diseases. The maintenance in energy production is crucial to face and recover from oxidative damage, and the preservation of different sources of energy production is essential to preserve neuronal function. Fingolimod phosphate is a drug with neuroprotective and antioxidant actions, used in the treatment of multiple sclerosis. This work was performed in a model of oxidative damage on neuronal cell cultures exposed to menadione in the presence or absence of fingolimod phosphate. We studied the mitochondrial function, antioxidant enzymes, protein nitrosylation, and several pathways related with glucose metabolism and glycolytic and pentose phosphate in neuronal cells cultures. Our results showed that menadione produces a decrease in mitochondrial function, an imbalance in antioxidant enzymes, and an increase in nitrosylated proteins with a decrease in glycolysis and glucose-6-phosphate dehydrogenase. All these effects were counteracted when fingolimod phosphate was present in the incubation media. These effects were mediated, at least in part, by the interaction of this drug with its specific S1P receptors. These actions would make this drug a potential tool in the treatment of neurodegenerative processes, either to slow progression or alleviate symptoms.

  • Neocortical tissue recovery in severe congenital obstructive hydrocephalus after intraventricular administration of bone marrow-derived mesenchymal stem cells
    María García-Bonilla, Betsaida Ojeda-Pérez, María L. García-Martín, M. Carmen Muñoz-Hernández, Javier Vitorica, Sebastián Jiménez, Manuel Cifuentes, Leonor Santos-Ruíz, Kirill Shumilov, Silvia Claros,et al.

    Springer Science and Business Media LLC
    Abstract Background In obstructive congenital hydrocephalus, cerebrospinal fluid accumulation is associated with high intracranial pressure and the presence of periventricular edema, ischemia/hypoxia, damage of the white matter, and glial reactions in the neocortex. The viability and short time effects of a therapy based on bone marrow-derived mesenchymal stem cells (BM-MSC) have been evaluated in such pathological conditions in the hyh mouse model. Methods BM-MSC obtained from mice expressing fluorescent mRFP1 protein were injected into the lateral ventricle of hydrocephalic hyh mice at the moment they present a very severe form of the disease. The effect of transplantation in the neocortex was compared with hydrocephalic hyh mice injected with the vehicle and non-hydrocephalic littermates. Neural cell populations and the possibility of transdifferentiation were analyzed. The possibility of a tissue recovering was investigated using 1H High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance (1H HR-MAS NMR) spectroscopy, thus allowing the detection of metabolites/osmolytes related with hydrocephalus severity and outcome in the neocortex. An in vitro assay to simulate the periventricular astrocyte reaction conditions was performed using BM-MSC under high TNFα level condition. The secretome in the culture medium was analyzed in this assay. Results Four days after transplantation, BM-MSC were found undifferentiated and scattered into the astrocyte reaction present in the damaged neocortex white matter. Tissue rejection to the integrated BM-MSC was not detected 4 days after transplantation. Hyh mice transplanted with BM-MSC showed a reduction in the apoptosis in the periventricular neocortex walls, suggesting a neuroprotector effect of the BM-MSC in these conditions. A decrease in the levels of metabolites/osmolytes in the neocortex, such as taurine and neuroexcytotoxic glutamate, also indicated a tissue recovering. Under high TNFα level condition in vitro, BM-MSC showed an upregulation of cytokine and protein secretion that may explain homing, immunomodulation, and vascular permeability, and therefore the tissue recovering. Conclusions BM-MSC treatment in severe congenital hydrocephalus is viable and leads to the recovery of the severe neurodegenerative conditions in the neocortex. NMR spectroscopy allows to follow-up the effects of stem cell therapy in hydrocephalus.

  • Safety and efficacy of the mesenchymal stem cell in feline eosinophilic keratitis treatment
    Antonio J. Villatoro, Silvia Claros, Viviana Fernández, Cristina Alcoholado, Fernando Fariñas, Antonio Moreno, José Becerra, and José A. Andrades

    Springer Science and Business Media LLC

  • Regenerative therapies in dry eye disease: From growth factors to cell therapy
    Antonio Villatoro, Viviana Fernández, Silvia Claros, Cristina Alcoholado, Manuel Cifuentes, Jesús Merayo-Lloves, José Andrades, and José Becerra

    Dry eye syndrome is a complex and insidious pathology with a high level of prevalence among the human population and with a consequently high impact on quality of life and economic cost. Currently, its treatment is symptomatic, mainly based on the control of lubrication and inflammation, with significant limitations. Therefore, the latest research is focused on the development of new biological strategies, with the aim of regenerating affected tissues, or at least restricting the progression of the disease, reducing scar tissue, and maintaining corneal transparency. Therapies range from growth factors and cytokines to the use of different cell sources, in particular mesenchymal stem cells, due to their multipotentiality, trophic, and immunomodulatory properties. We will review the state of the art and the latest advances and results of these promising treatments in this pathology.

  • Dendrimer surface orientation of the RGD peptide affects mesenchymal stem cell adhesion
    Y. Vida, D. Collado, F. Najera, S. Claros, J. Becerra, J. A. Andrades, and E. Perez-Inestrosa

    Royal Society of Chemistry (RSC)
    Mesenchymal stem cells (MSCs) are promising candidates for a range of tissue regeneration applications.

  • Use of adipose-derived mesenchymal stem cells in keratoconjunctivitis sicca in a canine model
    Antonio J. Villatoro, Viviana Fernández, Silvia Claros, Gustavo A. Rico-Llanos, José Becerra, and José A. Andrades

    Hindawi Limited
    Keratoconjunctivitis sicca (KCS) or dry eye disease (DED) is an immune-mediated multifactorial disease, with high level of prevalence in humans and dogs. Our aim in this study was to investigate the therapeutic effects of allogeneic adipose-derived mesenchymal stromal cells (Ad-MSCs) implanted around the lacrimal glands in 12 dogs (24 eyes) with KCS, which is refractory to current available treatments. Schirmer tear test (STT) and ocular surface integrity were assessed at 0 (before treatment), 3, 6, and 9 months after treatment. Average STT values and all clinical signs showed a statistically significant change(P<0.001)during the follow-up with reduction in all ocular parameters scored: ocular discharge, conjunctival hyperaemia, and corneal changes, and there were no signs of regression or worsening. Implanted cells were well tolerated and were effective reducing clinical signs of KCS with a sustained effect during the study period. None of the animals showed systemic or local complications during the study. To our knowledge, this is the first time in literature that implantation of allogeneic Ad-MSCs around lacrimal glands has been found as an effective therapeutic alternative to treat dogs with KCS. These results could reinforce a good effective solution to be extrapolated to future studies in human.

  • A novel human TGF-β1 fusion protein in combination with rhBMP-2 increases chondro-osteogenic differentiation of bone marrow mesenchymal stem cells
    Silvia Claros, Gustavo Rico-Llanos, José Becerra, and José Andrades

    Transforming growth factor-beta (TGF-β) is involved in processes related to the differentiation and maturation of osteoprogenitor cells into osteoblasts. Rat bone marrow (BM) cells were cultured in a collagen-gel containing 0.5% fetal bovine serum (FBS) for 10 days in the presence of rhTGF (recombinant human TGF)-β1-F2, a fusion protein engineered to include a high-affinity collagen-binding decapeptide derived from von Willebrand factor. Subsequently, cells were moderately expanded in medium with 10% FBS for 4 days and treated with a short pulse of rhBMP (recombinant human bone morphogenetic protein)-2 for 4 h. During the last 2 days, dexamethasone and β-glycerophosphate were added to potentiate osteoinduction. Concomitant with an up-regulation of cell proliferation, DNA synthesis levels were determined. Polymerase chain reaction was performed to reveal the possible stemness of these cells. Osteogenic differentiation was evaluated in terms of alkaline phosphatase activity and mineralized matrix formation as well as by mRNA expression of osteogenic marker genes. Moreover, cells were placed inside diffusion chambers and implanted subcutaneously into the backs of adult rats for 4 weeks. Histological study provided evidence of cartilage and bone-like tissue formation. This experimental procedure is capable of selecting cell populations from BM that, in the presence of rhTGF-β1-F2 and rhBMP-2, achieve skeletogenic potential in vitro and in vivo.

  • Large-scale dendrimer-based uneven nanopatterns for the study of local arginine-glycine-aspartic acid (RGD) density effects on cell adhesion
    Anna Lagunas, Albert G. Castaño, Juan M. Artés, Yolanda Vida, Daniel Collado, Ezequiel Pérez-Inestrosa, Pau Gorostiza, Silvia Claros, José A. Andrades, and Josep Samitier

    Springer Science and Business Media LLC

  • In vivo bioluminescence imaging of cell differentiation in biomaterials: A platform for scaffold development
    Juli R. Bagó, Elisabeth Aguilar, Maria Alieva, Carolina Soler-Botija, Olaia F. Vila, Silvia Claros, José A. Andrades, José Becerra, Nuria Rubio, and Jerónimo Blanco

    Mary Ann Liebert Inc
    In vivo testing is a mandatory last step in scaffold development. Agile longitudinal noninvasive real-time monitoring of stem cell behavior in biomaterials implanted in live animals should facilitate the development of scaffolds for tissue engineering. We report on a noninvasive bioluminescence imaging (BLI) procedure for simultaneous monitoring of changes in the expression of multiple genes to evaluate scaffold performance in vivo. Adipose tissue-derived stromal mensenchymal cells were dually labeled with Renilla red fluorescent protein and firefly green fluorescent protein chimeric reporters regulated by cytomegalovirus and tissue-specific promoters, respectively. Labeled cells were induced to differentiate in vitro and in vivo, by seeding in demineralized bone matrices (DBMs) and monitored by BLI. Imaging results were validated by RT-polymerase chain reaction and histological procedures. The proposed approach improves molecular imaging and measurement of changes in gene expression of cells implanted in live animals. This procedure, applicable to the simultaneous analysis of multiple genes from cells seeded in DBMs, should facilitate engineering of scaffolds for tissue repair.

  • Characterization of adult stem/progenitor cell populations from bone marrow in a three-dimensional collagen gel culture system
    Silvia Claros, Noela Rodríguez-Losada, Encarnación Cruz, Enrique Guerado, José Becerra, and José A. Andrades

    SAGE Publications
    Stem cell transplantation therapy using mesenchymal stem cells (MSCs) is considered a useful strategy. Although MSCs are commonly isolated by exploiting their plastic adherence, several studies have suggested that there are other populations of stem and/or osteoprogenitor cells that are removed from primary culture during media replacement. Therefore, we developed a three-dimensional (3D) culture system in which adherent and nonadherent stem cells are selected and expanded. Here, we described the characterization of 3D culture-derived cell populations in vitro and the capacity of these cells to differentiate into bone and/or cartilage tissue when placed inside of demineralized bone matrix (DBM) cylinders, implanted subcutaneously into the backs of rat for 2, 4, and 8 weeks. Our results demonstrates that 3D culture cells were a heterogeneous population of uncommitted cells that express pluripotent-, hematopoietic-, mesenchymal-, and endothelial-specific markers in vitro and can undergo osteogenic differentiation in vivo.

  • Induction of superficial zone protein (SZP)/lubricin/PRG 4 in muscle-derived mesenchymal stem/progenitor cells by transforming growth factor-β1 and bone morphogenetic protein-7
    José A Andrades, Shirley C Motaung, Pedro Jiménez-Palomo, Silvia Claros, José M López-Puerta, José Becerra, Thomas M Schmid, and A Hari Reddi

    Springer Science and Business Media LLC

  • Spinal arthrodesis: Bone morphogenetic proteins as more than one option

  • The effect of type I collagen on osteochondrogenic differentiation in adipose-derived stromal cells in vivo
    M. Alonso, S. Claros, J. Becerra, and Ja Andrades

    Elsevier BV
    BACKGROUND Recent studies have demonstrated that adipose-derived adult stromal cells (ADASCs) offer great promise for cell-based therapies due to their ability to differentiate towards bone, cartilage and fat [corrected] The objective of this study was to investigate whether type I collagen would elicit in vivo bone formation of passaged rat adipose-derived adult stromal cells (ADASC) placed extraskeletally. METHODS After expansion for 1-4 passages (P), cells were incubated in osteogenic medium containing dexamethasone, ascorbic acid and beta-glycerol phosphate for 2-4 weeks. Undifferentiated cells were maintained in Dulbecco's modified Eagle's medium (DMEM) with 10% fetal bovine serum (FBS). Osteogenic differentiation was evaluated by alkaline phosphatase (ALP) and von Kossa staining as well as by gene expression of ALP, osteopontin (OP), osteonectin (ON), osteocalcin (OC), collagen I (colI), collagen II (colII), bone sialoprotein (BSP), periostin (Postn), runx2, osterix (Osx), sox9, msx1 and msx2. Diffusion chambers were filled with 1x10(6) cells mixed with or without type I collagen gel and implanted subcutaneously into rats. Controls included chambers exposed to (1) undifferentiated cells (with or without collagen, (2) collagen without cells and (3) empty chambers (n=5 per group). RESULTS Four weeks after implantation, in vivo bone and cartilage formation was demonstrated in implants containing 4-week osteo-induced P1 and P4 cells wrapped in the collagen gel, as confirmed by Goldner's trichrome and Alcian blue staining, respectively. Newly formed bone stained positive for type I collagen. Control implants had no bone or cartilage and were primarily filled with fibrous tissue at that time interval. DISCUSSION Recent studies have demonstrated that ADASC offer great promise for cell-based therapies because of their ability to differentiate toward bone, cartilage and fat. However, the influence of different matrices on the in vivo osteogenic capability of ADASC is not fully understood. These findings suggest that type I collagen may support the survival and expression of osteogenic and chondrogenic phenotypes in passaged rat ADASC in vivo.

  • Autologous human-derived bone marrow cells exposed to a novel TGF-beta1 fusion protein for the treatment of critically sized tibial defect.
    José Becerra, Enrique Guerado, Silvia Claros, Mônica Alonso, María L Bertrand, Carlos González, and José A Andrades

    Future Medicine Ltd
    We report the first clinical case of transplantation of autologous bone marrow-derived cells in vitro exposed to a novel recombinant human transforming growth factor (rhTGF)-β1 fusion protein bearing a collagen-binding domain (rhTGF-β1-F2), dexamethasone (DEX) and β-glycerophosphate (β-GP). When such culture-expanded cells were loaded into porous ceramic scaffolds and transplanted into the bone defect of a 69-year-old man, they differentiated into bone tissue. Marrow cells were obtained from the iliac crest and cultured in collagen gels impregnated with rhTGF-β1-F2. Cells were selected under serum-restricted conditions in rhTGF-β1-F2-containing medium for 10 days, expanded in 20% serum for 22 days and osteoinduced for 3 additional days in DEX/β-GP-supplemented medium. We found that the cell number harvested from rhTGF-β1-F2-treated cultures was significantly higher (2.3- to 3-fold) than that from untreated cultures. rhTGF-β1-F2 treatment also significantly increased alkaline phosphatase activity (2.2- to 5-fold) and osteocalcin synthesis, while calcium was only detected in rhTGF-β1-F2-treated cells. Eight weeks after transplantation, most of the scaffold pores were filled with bone and marrow tissue. When we tested the same human cells treated in vitro in a rat model using diffusion chambers, there was subsequent development of cartilage and bone following the subcutaneous transplantation of rhTGF-β1-F2-treated cells. This supports the suggestion that such cells were marrow-derived cells, with chondrogenic and osteogenic potential, whereas the untreated cells were not under the same conditions. The ability for differentiation into cartilage and bone tissues, combined with an extensive proliferation capacity, makes such a marrow-derived stem cell population valuable to induce bone regeneration at skeletal defect sites.