María Villegas-pérez - Academia.edu (original) (raw)

Papers by María Villegas-pérez

PubMed, 2011

Purpose: To analyze the damage produced by light in mydriatic and miotic albino retinas under two... more Purpose: To analyze the damage produced by light in mydriatic and miotic albino retinas under two different sources of light. Methods: Albino Sprague Dawley female rats were exposed to 3,000 lx during 48 h under two different light sources: linear and circular bulbs. Before exposure, their left pupils were dilated. Before and at different times after light exposure (ALE), electroretinographic signals were recorded. One week before processing, retinal ganglion cells (RGCs) were traced by applying fluorogold on the superior colliculi. Just before processing, some animals were intravenously injected with horseradish peroxidase to analyze retinal vascular leakage. At different times ALE, animals were sacrificed and their retinas dissected as whole mounts or cross-sections. Cross-sections were used to study the retinal degeneration and to detect apoptotic nuclei by the transferase dUTP nick end labeling (TUNEL) technique. Whole mounts were used to analyze vascular leakage; investigate the nerve fiber layer, identified by immunodetection of neurofilaments; and quantify the whole population of RGCs identified by fluorogold tracing and Brn3a immunodetection. With the quantitative data, detailed isodensity maps were generated to study the spatial loss of RGCs. Results: Phototoxicity causes an immediate and permanent abolishment of the electroretinographic response. Early ALE, photoreceptors degenerate by apoptosis and this death is more severe in mydriatic conditions and under circular bulbs. Photoreceptor loss starts in an arciform dorsomedial retinal area, but at 3 months ALE has spread to the whole retina and there are no differences related to either pupil dilation or light source. Three months ALE, RGC axons show distorted trajectories and abnormal expression of neurofilaments. Six months or more ALE, there is significant death of RGCs caused by axonal strangulation by displaced inner retinal vessels. Topography of the surviving RGCs shows that their loss is not uniform throughout the retina. Conclusions: Light damage to photoreceptors depends on pupil dilation and light source, but affects all retinal layers with time. These deteriorative events are also observed in light-induced and inherited retinal degenerations in pigmented animals, but occur differently. Thus, the role of ocular pigmentation and the etiology of photoreceptor degeneration on retinal remodelling deserve further investigation.

Neural Regeneration Research, 2022

Retinal degenerative diseases affecting the outer retina in its many forms (inherited, acquired o... more Retinal degenerative diseases affecting the outer retina in its many forms (inherited, acquired or induced) are characterized by photoreceptor loss, and represent currently a leading cause of irreversible vision loss in the world. At present, there are very few treatments capable of preventing, recovering or reversing photoreceptor degeneration or the secondary retinal remodeling, which follows photoreceptor loss and can also cause the death of other retinal cells. Thus, these diseases are nowadays one of the greatest challenges in the field of ophthalmological research. Bone marrow derived-mononuclear stem cell transplantation has shown promising results for the treatment of photoreceptor degenerations. These cells may have the potential to slow down photoreceptor loss, and therefore should be applied in the early stages of photoreceptor degenerations. Furthermore, because of their possible paracrine effects, they may have a wide range of clinical applications, since they can potentially impact on several retinal cell types at once and photoreceptor degenerations can involve different cells and/or begin in one cell type and then affect adjacent cells. The intraocular injection of bone marrow derived-mononuclear stem cells also enhances the outcomes of other treatments aimed to protect photoreceptors. Therefore, it is likely that future investigations may combine bone marrow derived-mononuclear stem cell therapy with other systemic or intraocular treatments to obtain greater therapeutic effects in degenerative retinal diseases.

Eye

Objective The objective of this study was to analyse the results of the surgical treatment of coe... more Objective The objective of this study was to analyse the results of the surgical treatment of coexisting cataract and glaucoma and its effects on corneal endothelial cell density (CECD). Methods We include two longitudinal prospective studies: one randomised that included 40 eyes with open angle glaucoma that received one- (n = 20) or two-step (n = 20) phacotrabeculectomy and another that included 20 eyes that received phacoemulsification. We assess the impact of surgery on different clinical variables and in particular in CECD using Confoscan 4™ confocal microscopy and semiautomatic counting methods. Results Phacoemulsification and phacotrabeculectomy, but not trabeculectomy, increase significantly best-corrected visual acuity and anterior chamber depth and trabeculectomy and one- or two-step phacotrabeculectomy decreased similarly the intraocular pressure. We document percentages of endothelial cell loss of 3.1%, 17.9%, 31.6% and 42.6% after trabeculectomy, phacoemulsification and...

Scientific Reports

retinal neurons and the RPE, but no glial cells, were labeled with FG-filled vesicles. The tracer... more retinal neurons and the RPE, but no glial cells, were labeled with FG-filled vesicles. The tracer reached the RPE 15 minutes after FG administration, and this labeling remained up to 30 days. Tracing for 15 minutes or 24 hours did not cause oxidative stress. Intraretinal tracing delineated the pathological retinal remodelling occurring in the dystrophic strains. The RPE of the P23H-1 strain was highly altered in aged animals, while the Rpe of the RcS strain, which is unable to phagocytose, did not accumulate the tracer even at young ages when the retinal neural circuit is still preserved. in both dystrophic strains, the Rpe cells were pleomorphic and polymegathic.

Investigative Opthalmology & Visual Science

Citation: Di Pierdomenico J, Martínez-Vacas A, Hernández-Muñoz D, et al. Coordinated intervention... more Citation: Di Pierdomenico J, Martínez-Vacas A, Hernández-Muñoz D, et al. Coordinated intervention of microglial and Müller cells in light-induced retinal degeneration. Invest Ophthalmol Vis Sci. 2020;61(3):47. https://doi.org/10.1167/iovs.61.3.47 PURPOSE. To analyze the role of microglial and Müller cells in the formation of rings of photoreceptor degeneration caused by phototoxicity.

Experimental Eye Research

Investigative ophthalmology & visual science, Mar 1, 2018

To examine if light exposure exacerbates retinal neuronal loss induced by taurine depletion. Albi... more To examine if light exposure exacerbates retinal neuronal loss induced by taurine depletion. Albino rats received β-alanine in the drinking water to induce taurine depletion. One month later, half of the animals were exposed to white light (3000 lux) continuously for 48 hours and the rest remained in normal environmental conditions. A control group of animals nontreated with β-alanine also was prepared, and half of them were exposed to light using the same protocol. All the animals were processed 2 months after the beginning of the experiment. Retinas were dissected as wholemounts and immunodetected with antibodies against Brn3a, melanopsin, S-opsin, and L-opsin to label different retinal populations: Brn3a+ retinal ganglion cells (RGCs) (image-forming RGCs), m+RGCs (non-image-forming RGCs), and S- and L/M-cones, respectively. Light exposure did not affect the numbers of Brn3a+RGCs or m+RGCs but diminished the numbers of S- and L/M-cones and caused the appearance of rings devoid of ...

Investigative Opthalmology & Visual Science, 2016

Citation: Hadj-Saïd W, Froger N, Ivkovic I, et al. Quantitative and topographical analysis of the... more Citation: Hadj-Saïd W, Froger N, Ivkovic I, et al. Quantitative and topographical analysis of the losses of cone photoreceptors and retinal ganglion cells under taurine depletion. Invest Ophthalmol Vis Sci.

Molecular vision, Jan 5, 2009

To investigate the effects of laser photocoagulation (LP)-induced ocular hypertension (OHT) on th... more To investigate the effects of laser photocoagulation (LP)-induced ocular hypertension (OHT) on the survival and retrograde axonal transport of retinal ganglion cells (RGC), as well as on the function of retinal layers. Adult albino Swiss mice (35-45 g) received laser photocoagulation of limbal and episcleral veins in the left eye. Mice were sacrificed at 8, 17, 35, and 63 days. Intraocular pressure (IOP) in both eyes was measured with a Tono-Lab before LP and at various days after LP. Flash electroretinogram (ERG) scotopic threshold response (STR) and a- and b-wave amplitudes were recorded before LP and at various times after LP. RGCs were labeled with 10% hydroxystilbamidine methanesulfonate (OHSt) applied to both superior colliculi before sacrifice and in some mice, with dextran tetramethylrhodamine (DTMR) applied to the ocular stump of the intraorbitally transected optic nerve. Retinas were immunostained for RT97 or Brn3a. Retinas were prepared as whole-mounts and photographed un...

Ocular Neuroprotection, 2003

8 Retinal Ischemia Manuel Vidal-Sanz, Marıa P. Lafuente, Inmaculada Selles-Navarro, Marıa E. Rodr... more 8 Retinal Ischemia Manuel Vidal-Sanz, Marıa P. Lafuente, Inmaculada Selles-Navarro, Marıa E. Rodrıguez, Sergio Mayor-Torroglosa, and Marıa P. Villegas-Perez Universidad de Murcia Murcia, Spain I ... Osborne NN, Ugarte M, Chao M, Chidlow G, Bae JH, Wood JPM, Nash MS. ...

British Journal of Ophthalmology, 2014

Aims To investigate the cause of retinal ganglion cell (RGC) loss in dystrophic aged Royal Colleg... more Aims To investigate the cause of retinal ganglion cell (RGC) loss in dystrophic aged Royal College of Surgeons (RCS) rats. Methods RCS-p+ (dystrophic) female rats of postnatal times (P365, P450 and P540) and age-matched RCS-p1 rdy+ (non-dystrophic) rats were used. In whole-mounted retinas, RGCs were doubly labelled with Fluorogold (FG) retrogradely transported from the superior colliculi and Brn3a immunohistochemistry. RGC axons were labelled with anti-neurofilament antibodies. Automatic image analysis techniques allowed quantification of the total population of RGCs per retina and construction of isodensity maps to investigate RGC topology. Results Dystrophic retinas showed at all times studied wedge-shaped sectors devoid of FG + and Brn3a + RGCs. These sectors were also devoid of neurofilament-labelled axons. The total number of FG + RGC and Brn3a + RGC per retina was significantly smaller in dystrophic rats at P540, revealing RGC death at this age. The total number of FG + RGCs was smaller than those of Brn3a + RGCs at P540, indicating a disturbance of the retrograde axonal transport at this age. Conclusions RGC double labelling documents that sectorial RGC loss in aged dystrophic RCS rats is mainly due to RGC death, although a deficit of the retrograde axonal transport exists also at the more advanced ages.

Molecular vision, 2012

To investigate the anatomic and functional changes triggered by light exposure in the albino mous... more To investigate the anatomic and functional changes triggered by light exposure in the albino mouse retina and compare them with those observed in the albino rat. BALB/c albino mice were exposed to 3,000 lx of white light during 24 h and their retinas analyzed from 1 to 180 days after light exposure (ALE). Left pupil mydriasis was induced with topical atropine. Retinal function was analyzed by electroretinographic (ERG) recording. To assess retinal degeneration, hematoxylin and eosin staining, the TdT-mediated dUTP nick-end labeling (TUNEL) technique, and quantitative immunohistofluorescence for synaptophysin and protein kinase Cα (PKCα) were used in cross sections. Intravenous injection of horseradish peroxidase and Fluoro-Gold™ tracing were used in whole-mounted retinas to study the retinal vasculature and the retinal ganglion cell (RGC) population, respectively. Light exposure caused apoptotic photoreceptor death in the central retina. This death was more severe in the dorsal than...

Investigative Ophthalmology & Visual Science, 2013

Citation: García-Ayuso D, Ortín-Martínez A, Jiménez-López M, et al. Changes in the photoreceptor ... more Citation: García-Ayuso D, Ortín-Martínez A, Jiménez-López M, et al. Changes in the photoreceptor mosaic of P23H-1 rats during retinal degeneration: implications for rod-cone dependent survival. Invest Ophthalmol Vis Sci. 2013;54:5888-5900.

Neurotoxicity Research, 2000

substances with neuroprotective effects, by altering steps of the cascade of events leading to ce... more substances with neuroprotective effects, by altering steps of the cascade of events leading to cell death.

Acta neurobiologiae experimentalis

The capacity of injured nerve cells to regrow and form terminal connections in the CNS of adult m... more The capacity of injured nerve cells to regrow and form terminal connections in the CNS of adult mammals was investigated in axotomized retinal ganglion cells (RGCs) of rodents whose optic nerves were substituted by an autologous segment of peripheral nerve. While many RGCs died after axotomy approximately 20% of the surviving RGCs regenerated axons several cm in length. Some of the regenerated RGC axons entered the superior colliculus where they arborized and formed well differentiated synapses that transynaptically excited or inhibited tectal neurons.

Investigative Opthalmology & Visual Science, 2015

We evaluated the photoreceptor response of pigmented P23H and normal pigmented Long Evans (LE) ra... more We evaluated the photoreceptor response of pigmented P23H and normal pigmented Long Evans (LE) rats over time using functional tests in variable lighting conditions. Pigmented P23H rats were studied by optomotor testing and electroretinogram (ERG) recordings at P30, P150, and P240. Pigmented LE rats were used as a normal wild-type control. Stimuli were modified with colored filters. Neutral density filters were used to reduce luminance. Age-related decreases in visual acuity (VA) and contrast sensitivity (CS) were observed in P23H rats. Good correlations in measurements without filter and with green filter were observed between LE and P23H P30 rat values. Differences between groups were smaller with red and purple filters. A strong relationship with luminance was observed in LE rats (VA and CS) and with P23H P30 rats (CS). A decline in the ERG responses of P23H rats was consistent with the gradual loss of photoreceptors. Differences in a- and b-wave amplitudes with different colored filters were negligible with the exception of the red filter, which resulted in smaller responses. Visual function parameters decreased with age in pigmented P23H rats. Irrespective of luminance, color filter, and retinal degeneration, minimum thresholds of VA and CS were found. Smaller differences than expected were found using color filters. Responses to functional tests at long wavelengths were observed, where there is very low photoreceptor spectral sensitivity. The use of filters with functional testing could minimize light-induced retinal damage in rats.

Experimental Neurology

To study the retrograde labeling of intact and axotomized retinal ganglion cells (RGCs) over long... more To study the retrograde labeling of intact and axotomized retinal ganglion cells (RGCs) over long periods of time, we applied the carbocyanine dye diI to the superior colliculi (SC) and dorsal lateral geniculate nuclei (dLGN) in adult albino rats and examined the retinas by fluorescence microscopy after different periods of survival. Retrogradely labeled RGCs, which were observed in the retinas as early as 3 days after application of the dye, gradually increased in density so that by 7 days more than 80% of the RGCs were labeled and by 30 days diI-labeled cell densities were similar to those observed after short applications of other tracers. Using short-term retrograde labeling with fast blue (FB) as an independent marker of RGCs, it was determined that these neurons remained labeled with diI for periods of up to 9 months without apparent leakage of the tracer to other retinal cells. In addition, diI labeling persisted in the somata of more than 80% of axotomized RGCs whose contact...