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Ugarte M.,Moorfields Eye Hospital | Grime G.W.,University of Surrey | Osborne N.N.,Instituto Oftalmologico Fernandez Vega
Metallomics | Year: 2014

Proton-induced X-ray emission (PIXE) in combination with 3D depth profiling with Rutherford backscattering spectrometry (RBS) was used to establish the distribution and concentration of trace elements within individual corneal and retinal areas in frozen sections from adult male Wistar rats (n = 6). The distribution of endogenous trace elements in the cornea and retina is non-homogenous. The most abundant metal in the cornea is calcium followed by zinc. Iron and copper are present in small amounts localised particularly to the epithelium. Iron is also identified in keratocytes. Relatively high levels of calcium occur in the corneal epithelial cell bodies. Zinc has a wide intense distribution across the corneal epithelium (with greater levels in the basal part) and posterior stroma. In the retina, zinc is the most common metal followed by iron and copper. Relatively high levels of zinc exist in the retinal pigment epithelium (RPE), photoreceptor inner segments (RIS) and inner nuclear layer (INL). Chelatable zinc was localised with fluorescent TSQ in the RPE, RIS and plexiform layers. It is interesting to note that the highest levels of total zinc and the greatest intensity of chelatable zinc staining do not coincide. In the RPE and corneal epithelium, zinc co-localised with the zinc-containing metallothioneins (MT). However, there was a clear mismatch between the localisation of the most intense levels of zinc in the neuroretina (i.e. INL) and corneal posterior stroma with that reported for MT. For example, the presence of zinc is not particularly associated with the retinal ganglion cells, retinal area that contains MTs in significant amounts. While high amounts of zinc are present in the INL and corneal posterior stroma, which are largely devoid of MTs. This probably represents pools of static, catalytic and structural zinc associated with substances other than the MTs. © 2014 The Royal Society of Chemistry.

Anitua E.,Biotechnology Institute BTI | Merayo-Lloves J.,Instituto Oftalmologico Fernandez Vega | de La Fuente M.,Biotechnology Institute BTI | Muruzabal F.,Biotechnology Institute BTI | Orive G.,Biotechnology Institute BTI
Investigative Ophthalmology and Visual Science | Year: 2011

PURPOSE. Plasma rich in growth factors (PRGF-Endoret) technology is an autologous platelet-enriched plasma obtained from patient's own blood, which after activation with calcium chloride allows the release of a pool of biologically active proteins that influence and promote a range of biological processes including cell recruitment, and growth and differentiation. Because ocular surface wound healing is mediated by different growth factors, we decided to explore the potential of PRGFEndoret technology in stimulating the biological processes related with fibroblast-induced tissue repair. Furthermore, the anti-fibrotic properties of this technology were also studied. METHODS. Blood from healthy donors was collected, centrifuged and, whole plasma column (WP) and the plasma fraction with the highest platelet concentration (F3) were drawn off, avoiding the buffy coat. Primary human cells including keratocytes and conjunctival fibroblasts were used to perform the "in vitro" investigations. The potential of PRGF-Endoret in promoting wound healing was evaluated by means of a proliferation and migration assays. Fibroblast cells were induced to myofibroblast differentiation after the treatment with 2.5 ng/mL of TGF-β1. The capability of WP and F3 to prevent and inhibit TGF-β1-induced differentiation was evaluated. RESULTS. Results show that this autologous approach significantly enhances proliferation and migration of both keratocytes and conjunctival fibroblasts. In addition, plasma rich in growth factors prevents and inhibits TGF-β1-induced myofibroblast differentiation. No differences were found between WP and F3 plasma fractions. CONCLUSIONS. These results suggest that PRGF-Endoret could reduce scarring while stimulating wound healing in ocular surface. F3 or whole plasma column show similar biological effects in keratocytes and conjunctival fibroblast cells. © 2011 The Association for Research in Vision and Ophthalmology, Inc.

Ugarte M.,Moorfields Eye Hospital | Osborne N.N.,Instituto Oftalmologico Fernandez Vega
Metallomics | Year: 2014

Zinc levels are high in ocular tissues and the distribution is non-uniform. Zinc is particularly concentrated in the corneal epithelium and posterior stroma. Zinc is the most abundant trace metal in the retina. Bound-zinc is particularly located in the inner nuclear layer, (e.g. forming part of the structure of zinc finger transcription factors), while loosely-bound zinc is prominent in the retinal pigment epithelium and photoreceptor layers. Loosely-bound zinc ions in the photoreceptors might play a role in the phototransduction cascade and rhodopsin regeneration. Loosely-bound zinc is also found in presynaptic vesicles of photoreceptor cells in the outer plexiform and inner plexiform layers and can be synaptically released to affect both ionotropic and metabotropic receptors and also ion channels to modulate neurotransmission. The correct amount of loosely-bound zinc ions is maintained by regulating the function of zinc transporters, sensors and trafficking/storage proteins (i.e. metallothionein). The retinal homeostasis of zinc is dysregulated in systemic zinc depletion, aging and diseases such as age-related macular degeneration. Manipulation of retinal zinc metabolism in these situations might improve visual function. © 2014 The Royal Society of Chemistry.

Ugarte M.,University of Manchester | Osborne N.N.,Instituto Oftalmologico Fernandez Vega | Osborne N.N.,University of Oxford | Brown L.A.,University of Oxford | Bishop P.N.,University of Manchester
Survey of Ophthalmology | Year: 2013

The essential trace metals iron, zinc, and copper play important roles both in retinal physiology and disease. They are involved in various retinal functions such as phototransduction, the visual cycle, and the process of neurotransmission, being tightly bound to proteins and other molecules to regulate their structure and/or function or as unbound free metal ions. Elevated levels of "free" or loosely bound metal ions can exert toxic effects, and in order to maintain homeostatic levels to protect retinal cells from their toxicity, appropriate mechanisms exist such as metal transporters, chaperones, and the presence of certain storage molecules that tightly bind metals to form nontoxic products. The pathways to maintain homeostatic levels of metals are closely interlinked, with various metabolic pathways directly and/or indirectly affecting their concentrations, compartmentalization, and oxidation/reduction states. Retinal deficiency or excess of these metals can result from systemic depletion and/or overload or from mutations in genes involved in maintaining retinal metal homeostasis, and this is associated with retinal dysfunction and pathology. Iron accumulation in the retina, a characteristic of aging, may be involved in the pathogenesis of retinal diseases such as age-related macular degeneration (AMD). Zinc deficiency is associated with poor dark adaptation. Zinc levels in the human retina and RPE decrease with age in AMD. Copper deficiency is associated with optic neuropathy, but retinal function is maintained. The changes in iron and zinc homeostasis in AMD have led to the speculation that iron chelation and/or zinc supplements may help in its treatment. © 2013 Elsevier Inc.

Anitua E.,Biotechnology Institute BTI | Muruzabal F.,Biotechnology Institute BTI | De la Fuente M.,Biotechnology Institute BTI | Merayo-Lloves J.,Instituto Oftalmologico Fernandez Vega | Orive G.,Biotechnology Institute BTI
Experimental Eye Research | Year: 2014

We have developed and characterized a new type of plasma rich in growth factors (PRGF) derived eye-drop therapy for patients suffering from autoimmune diseases. To determine the concentration of several growth factors, proteins, immunoglobulins and complement activity of the heat-inactivated eye-drop and to study its biological effects on cell proliferation and migration of different ocular surface cells, blood from healthy donors was collected, centrifuged and PRGF was prepared avoiding the buffy coat. The half volume of the obtained plasma supernatant from each donor was heat-inactivated at 56°C for 1h (heat-inactivated PRGF). The concentration of several proteins involved on corneal wound healing, immunoglubolins G, M and E and functional integrity of the complement system assayed by CH50 test were determined. The proliferative and migratory potential of inactivated and non-inactivated PRGF eye drops were assayed on corneal epithelial cells (HCE), keratocytes (HK) and conjunctival fibroblasts (HConF). Heat-inactivated PRGF preserves the content of most of the proteins and morphogens involved in its wound healing effects while reduces drastically the content of IgE and complement activity. Heat-inactivated PRGF eye drops increased proliferation and migration potential of ocular surface cells with regard to PRGF showing significant differences on proliferation and migration rate of HCE and HConF respectively. In summary, heat-inactivation of PRGF eye drops completely reduced complement activity and deceased significantly the presence of IgE, maintaining the biological activity of PRGF on ocular surface cells.© 2013 Elsevier Ltd.

Anitua E.,Instituto Eduardo Anitua | Muruzabal F.,Instituto Eduardo Anitua | Pino A.,Instituto Eduardo Anitua | Merayo-Lloves J.,Instituto Oftalmologico Fernandez Vega | Orive G.,Instituto Eduardo Anitua
Cornea | Year: 2013

Purpose: We evaluated whether plasma rich in growth factors eye drops maintain their composition and biological activity after storage for 3 months at 220°C and after storage at 4°C or room temperature (RT) for 24 hours, compared with samples obtained at time 0 (fresh samples). Methods: Blood from 10 healthy donors was collected, centrifuged, and plasma rich in growth factors was prepared by avoiding the collection of the buffy coat. Eye drops were kept fresh or were stored at 220°C for 15, 30, and 90 days. For each time, 2 aliquots were kept at RT or at 4°C for 24 hours. Osmolarity, vitamin A, fibronectin, plateletderived growth factor-AB, vascular endothelial growth factor, epithelial growth factor, and transforming growth factor-β1 were quantified. The proliferative and migratory potential of the eye drops was assayed on primary human keratocytes. Results: Platelet-derived growth factor-AB, vascular endothelial growth factor, epithelial growth factor, and vitamin A levels remained constant for each time and for each storage condition, whereas fibronectin, transforming growth factor-β1, and osmolarity values were slightly modified after freezing. Cell proliferation and migration were significantly enhanced with the biological eye drops independently of the time and the storage condition. No microbial contamination was observed in any plasma rich in growth factors eye drops. Conclusions: Plasma rich in growth factors eye drops can be stored for up to 3 months without any reduction of the main proteins involved in ocular surface healing. Their use during 24 hours either at 4°C or at RT did not alter the composition and the in vitro biological activity of the eye drops. Copyrigt © 2013 Lippincott Williams & Wilkins.

Kamalden T.A.,University of Oxford | Ji D.,University of Oxford | Osborne N.N.,University of Oxford | Osborne N.N.,Instituto Oftalmologico Fernandez Vega
Neurochemical Research | Year: 2012

The aim of the present studies was to characterise cell death following inhibition of mitochondrial complex I with rotenone in a transformed cell line (RGC-5 cells) and to examine the neuroprotective properties of the flavonoids genistein, epigallocatechin gallate (EGCG), epicatechin (EC) and baicalin. Rotenone-induced cell death of RGC-5 cells results in a generation of reactive oxygen species, a breakdown of DNA, the translocation of membrane phosphatidylserine, an up-regulation of haemoxygenase-1 and is unaffected by necrostatin-1 (inhibitor of necroptosis), z-VAD-fmk (pan caspase inhibitor) or NU1025 (PARP inhibitor) but attenuated with SP600125 (JNK inhibitor). Rotenone-induced toxicity of RGC-5 cells also caused an activation of mitogen-activated kinases indicated by an up-regulation and translocation into mitochondria of p-c-Jun, pJNK and pp38. Exposure of RGC-5 cells to rotenone does not affect apoptosis inducing factor or significantly stimulate caspase-3 activity. EGCG and EC both significantly blunt rotenone toxicity of RGC-5 cells at concentrations of 50 μM while genistein and baicalin were without effect. Significantly, genistein is approximately 20 times less efficacious than EGCG (IC 50 2.5 μM) and EC (IC 50 1.5 μM) at inhibiting sodium nitroprusside-induced lipid peroxidation. These studies show that rotenone toxicity of RGC-5 cells is neither necroptosis nor caspasedependent apoptosis but involves the activation of mitogen-activated kinases and is inhibited by a JNK inhibitor, EGCG and EC. Genistein attenuates lipid peroxidation less efficaciously than EC and EGCG and does not affect rotenone toxicity of RGC-5 cells. © Springer Science+Business Media, LLC 2012.

Coca-Prados M.,Yale University | Coca-Prados M.,Instituto Oftalmologico Fernandez Vega
Journal of Glaucoma | Year: 2014

The blood-aqueous barrier of the eye is composed by tight junctions in the ciliary process nonpigmented epithelium, the endothelial cells in the iris vasculature, and the inner wall endothelium of Schlemm's canal. Tight junctions are gatekeepers of the paracellular transport limiting the selective diffusion of ions and small solutes through the space between neighboring cells. Tight junctions (ie, junctional adhesion molecules, claudins, occludins, zonula occludens, cingulin) are part of the apical junctional complex that also includes the adherens junctions (ie, cadherin-catenin and nectin-afadin complexes) and the gap junctions (ie, connexins). These junctional complexes respond rapidly to pharmacologic agents and physiological changes. Barrier dysfunction can contribute to the pathophysiology of inflammatory ocular diseases in a passive way by the vascular leakage of blood-borne molecules and inflammatory cells into the anterior segment of the eye. Copyright © 2014 by Lippincott Williams & Wilkins.

Alfonso J.F.,Instituto Oftalmologico Fernandez Vega | Knorz M.,FreeVis Zentrum Universitatsklinikum | Rincon J.L.,Instituto Oftalmologico IUMO CA | Suarez E.,Instituto Oftalmologico IUMO CA | And 2 more authors.
Journal of Cataract and Refractive Surgery | Year: 2014

Purpose To assess visual outcomes after bilateral implantation of an apodized +3.0 diopter (D) addition power toric diffractive multifocal intraocular lens (IOL). Setting Five study sites in Europe and South America. Design Cohort study. Methods Patients had bilateral implantation of the AcrySof® IQ ReSTOR®+3.0 D toric multifocal IOL. Inclusion criteria were age from 21 to 70 years, need for bilateral cataract extraction or refractive lens exchange, and regular corneal astigmatism from 0.75 to 2.5 D. Six-month evaluations included spherical equivalent (SE), refractive and corneal cylinder, visual acuity at various distances, defocus testing, reading speed, and IOL rotation. Results Forty-four of 49 patients completed the 6-month visit. The mean SE (88 eyes) was 0.09 D ± 0.49 (SD) at 6 months (±1.00 D in 95.2%). The mean refractive cylinder decreased from 1.07 ± 0.71 D to 0.33 ± 0.44 D (≤0.50 D in 78.6% and ≤1.00 D in 92.9%). The mean binocular uncorrected visual acuity was 0.04 ± 0.08 logMAR at preferred near (∼39 cm), 0.07 ± 0.09 logMAR at 40 cm, 0.09 ± 0.11 logMAR at 60 cm, and 0.05 ± 0.10 logMAR at 4 m. The mean corrected reading speed increased from 125.43 ± 33.58 words per minute (wpm) to 132.68 ± 23.69 wpm. The mean IOL rotation was 2.20 ± 4.34 degrees. Conclusion Six months after implantation of the toric multifocal IOL, patients had significantly reduced SE and refractive cylinder, good visual acuity across distances, increased reading speed, and minimal IOL rotation. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned. © 2013 ASCRS and ESCRS.

Wurm A.,University of Leipzig | Pannicke T.,University of Leipzig | Iandiev I.,University of Leipzig | Francke M.,University of Leipzig | And 5 more authors.
Progress in Retinal and Eye Research | Year: 2011

Purines (in particular, ATP and adenosine) act as neuro- and gliotransmitters in the sensory retina where they are involved in bidirectional neuron-glia signaling. This review summarizes the present knowledge about the expression and functional importance of P1 (adenosine) and P2 (nucleotide) receptors in Müller glial cells of the mammalian retina. Mammalian Müller cells express various subtypes of adenosine receptors and metabotropic P2Y receptors. Human Müller cells also express ionotropic P2X 7 receptors. Müller cells release ATP upon activation of metabotropic glutamate receptors and/or osmotic membrane stretching. The osmotic mechanism is abrogated under conditions associated with ischemia-hypoxia and inflammation, resulting in swelling of the Müller cells when the extracellular milieu is hypoosmotic. However, exogenous glutamate, which induces the release of ATP and adenosine, and thus activates P2Y 1 and A 1 adenosine receptors, respectively, prevents such osmotic swelling under pathological conditions, suggesting unimpaired receptor-induced release of ATP. In addition to the inhibition of swelling, which is implicated in regulating the volume of the extracellular space, purinergic signaling is involved in mediating neurovascular coupling. Furthermore, purinergic signals stimulate the proliferation of retinal precursor cells and Müller cells. In normal retinal information processing, Müller cells regulate the synaptic activity by the release of ATP and adenosine. In retinopathies, abrogation of the osmotic release of ATP, and the upregulation of ecto-apyrase (NTPDase1), may have neuroprotective effects by preventing the overactivation of neuronal P2X receptors that are implicated in apoptotic cell death. Pharmacological modulation of purinergic receptors of Müller cells may have clinical importance, e.g., for the clearance of retinal edema and for the inhibition of dysregulated cell proliferation in proliferative retinopathies. © 2011 Elsevier Ltd.

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