Neurotrophic molecules in the treatment of neurodegenerative disease with focus on the retina: status and perspectives

Effects of different alkylating agents on photoreceptor degeneration and proliferative response of Müller glia

Animal models for retinal degeneration are essential for elucidating its pathogenesis and developing new therapeutic strategies in humans. N-methyl-N-nitrosourea (MNU) has been extensively used to construct a photoreceptor-specific degeneration model, which has served to unveil the molecular process of photoreceptor degeneration as well as the mechanisms regulating the protective responses of remaining cells. Methyl methanesulphonate (MMS), also known to cause photoreceptor degeneration, is considered a good alternative to MNU due to its higher usability; however, detailed pathophysiological processes after MMS treatment remain uncharacterized. Here, we analyzed the time course of photoreceptor degeneration, Müller glial proliferation, and expression of secretory factors after MNU and MMS treatments in rats. While the timing of rod degeneration was similar between the treatments, we unexpectedly found that cones survived slightly longer after MMS treatment. Müller glia reentered the cell cycle at a similar timing after the two treatments; however, the G1/S transition occurred earlier after MMS treatment. Moreover, growth factors such as FGF2 and LIF were more highly upregulated in the MMS model. These data suggest that comparative analyses of the two injury models may be beneficial for understanding the complex regulatory mechanisms underlying the proliferative response of Müller glia.

Advancing precision medicines for ocular disorders: Diagnostic genomics to tailored therapies

Successful sequencing of the human genome and evolving functional knowledge of gene products has taken genomic medicine to the forefront, soon combining broadly with traditional diagnostics, therapeutics, and prognostics in patients. Recent years have witnessed an extraordinary leap in our understanding of ocular diseases and their respective genetic underpinnings. As we are entering the age of genomic medicine, rapid advances in genome sequencing, gene delivery, genome surgery, and computational genomics enable an ever-increasing capacity to provide a precise and robust diagnosis of diseases and the development of targeted treatment strategies. Inherited retinal diseases are a major source of blindness around the world where a large number of causative genes have been identified, paving the way for personalized diagnostics in the clinic. Developments in functional genetics and gene transfer techniques has also led to the first FDA approval of gene therapy for LCA, a childhood blindness. Many such retinal diseases are the focus of various clinical trials, making clinical diagnoses of retinal diseases, their underlying genetics and the studies of natural history important. Here, we review methodologies for identifying new genes and variants associated with various ocular disorders and the complexities associated with them. Thereafter we discuss briefly, various retinal diseases and the application of genomic technologies in their diagnosis. We also discuss the strategies, challenges, and potential of gene therapy for the treatment of inherited and acquired retinal diseases. Additionally, we discuss the translational aspects of gene therapy, the important vector types and considerations for human trials that may help advance personalized therapeutics in ophthalmology. Retinal disease research has led the application of precision diagnostics and precision therapies; therefore, this review provides a general understanding of the current status of precision medicine in ophthalmology.

Better Bioactivity, Cerebral Metabolism and Pharmacokinetics of Natural Medicine and Its Advanced Version

Currently, many people are afflicted by cerebral diseases that cause dysfunction in the brain and perturb normal daily life of people. Cerebral diseases are greatly affected by cerebral metabolism, including the anabolism and catabolism of neurotransmitters, hormones, neurotrophic molecules and other brain-specific chemicals. Natural medicines (NMs) have the advantages of low cost and low toxicity. NMs are potential treatments for cerebral diseases due to their ability to regulate cerebral metabolism. However, most NMs have low bioavailability due to their low solubility/permeability. The study is to summarize the better bioactivity, cerebral metabolism and pharmacokinetics of NMs and its advanced version. This study sums up research articles on the NMs to treat brain diseases. NMs affect cerebral metabolism and the related mechanisms are revealed. Nanotechnologies are applied to deliver NMs. Appropriate delivery systems (exosomes, nanoparticles, liposomes, lipid polymer hybrid nanoparticles, nanoemulsions, protein conjugation and nanosuspensions, etc.) provide better pharmacological and pharmacokinetic characteristics of NMs. The structure-based metabolic reactions and enzyme-modulated catalytic reactions related to advanced versions of NMs alter the pharmacological activities of NMs.

Animal Models of LED-Induced Phototoxicity. Short- and Long-Term In Vivo and Ex Vivo Retinal Alterations

Phototoxicity animal models have been largely studied due to their degenerative communalities with human pathologies, e.g., age-related macular degeneration (AMD). Studies have documented not only the effects of white light exposure, but also other wavelengths using LEDs, such as blue or green light. Recently, a blue LED-induced phototoxicity (LIP) model has been developed that causes focal damage in the outer layers of the superior-temporal region of the retina in rodents. In vivo studies described a progressive reduction in retinal thickness that affected the most extensively the photoreceptor layer. Functionally, a transient reduction in a- and b-wave amplitude of the ERG response was observed. Ex vivo studies showed a progressive reduction of cones and an involvement of retinal pigment epithelium cells in the area of the lesion and, in parallel, an activation of microglial cells that perfectly circumscribe the damage in the outer retinal layer. The use of neuroprotective strategies such as intravitreal administration of trophic factors, e.g., basic fibroblast growth factor (bFGF), brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF) or pigment epithelium-derived factor (PEDF) and topical administration of the selective alpha-2 agonist (Brimonidine) have demonstrated to increase the survival of the cone population after LIP.

Neurovascular unit in diabetic retinopathy: pathophysiological roles and potential therapeutical targets

Diabetic retinopathy (DR), one of the common complications of diabetes, is the leading cause of visual loss in working-age individuals in many industrialized countries. It has been traditionally regarded as a purely microvascular disease in the retina. However, an increasing number of studies have shown that DR is a complex neurovascular disorder that affects not only vascular structure but also neural tissue of the retina. Deterioration of neural retina could precede microvascular abnormalities in the DR, leading to microvascular changes. Furthermore, disruption of interactions among neurons, vascular cells, glia and local immune cells, which collectively form the neurovascular unit, is considered to be associated with the progression of DR early on in the disease. Therefore, it makes sense to develop new therapeutic strategies to prevent or reverse retinal neurodegeneration, neuroinflammation and impaired cell-cell interactions of the neurovascular unit in early stage DR. Here, we present current perspectives on the pathophysiology of DR as a neurovascular disease, especially at the early stage. Potential novel treatments for preventing or reversing neurovascular injuries in DR are discussed as well.

The lack of Irs2 induces changes in the immunocytochemical expression of aromatase in the mouse retina

Insulin receptor substrate (Irs) belongs to a family of proteins that mediate the intracellular signaling of insulin and IGF-1. Insulin receptor substrate 2 (Irs2) is necessary for retinal function, since its failure in Irs2-deficient mice in hyperglycemic situation promotes photoreceptor degeneration and visual dysfunction, like in diabetic retinopathy. The expression of P450 aromatase, which catalyzes androgen aromatization to form 17ß-estradiol, increases in some neurodegenerative diseases thus promoting the local synthesis of neuroestrogens that exert relevant neuroprotective functions. Aromatase is also expressed in neurons and glial cells of the central nervous system (CNS), including the retina. To further understand the role of Irs2 at the retinal level, we performed an immunocytochemical study in adult normoglycemic Irs2-deficient mice. For this aim, the retinal immunoexpression of neuromodulators, such as aromatase, glutamine synthetase (GS), and tyrosine hydroxylase (TH) was analyzed, joint to a morphometric and planimetric study of the retinal layers. Comparing with wild-type (WT) control mice, the Irs2-knockout (Irs2-KO) animals showed a significant increase in the immunopositivity to aromatase in almost all of the retinal layers. Besides, Irs2-KO mice exhibited a decreased immunopositive reaction for GS and TH, in Müller and amacrine cells, respectively; morphological variations were also found in these retinal cell types. Furthermore, the retina of Irs2-KO mice displayed alterations in the structural organization, and a generalized decrease in the retinal thickness was observed in each of the layers, except for the inner nuclear layer. Our findings suggest that the absence of Irs2 induces retinal neurodegenerative changes in Müller and amacrine cells that are unrelated to hyperglycemia. Accordingly, in the Irs2-KO mice, the increased retinal immunocytochemical reactivity of aromatase could be associated with an attempt to repair such neural retina injuries by promoting local neuroprotective mediators.

Looking into the future: Gene and cell therapies for glaucoma

Glaucoma is a complex group of optic neuropathies that affects both humans and animals. Intraocular pressure (IOP) elevation is a major risk factor that results in the loss of retinal ganglion cells (RGCs) and their axons. Currently, lowering IOP by medical and surgical methods is the only approved treatment for primary glaucoma, but there is no cure, and vision loss often progresses despite therapy. Recent technologic advances provide us with a better understanding of disease mechanisms and risk factors; this will permit earlier diagnosis of glaucoma and initiation of therapy sooner and more effectively. Gene and cell therapies are well suited to target these mechanisms specifically with the potential to achieve a lasting therapeutic effect. Much progress has been made in laboratory settings to develop these novel therapies for the eye. Gene and cell therapies have already been translated into clinical application for some inherited retinal dystrophies and age-related macular degeneration (AMD). Except for the intravitreal application of ciliary neurotrophic factor (CNTF) by encapsulated cell technology for RGC neuroprotection, there has been no other clinical translation of gene and cell therapies for glaucoma so far. Possible application of gene and cell therapies consists of long-term IOP control via increased aqueous humor drainage, including inhibition of fibrosis following filtration surgery, RGC neuroprotection and neuroregeneration, modification of ocular biomechanics for improved IOP tolerance, and inhibition of inflammation and neovascularization to prevent the development of some forms of secondary glaucoma.

Mutation-Independent Therapies for Retinal Diseases: Focus on Gene-Based Approaches

Gene therapy is proving to be an effective approach to treat or prevent ocular diseases ensuring a targeted, stable, and regulated introduction of exogenous genetic material with therapeutic action. Retinal diseases can be broadly categorized into two groups, namely monogenic and complex (multifactorial) forms. The high genetic heterogeneity of monogenic forms represents a significant limitation to the application of gene-specific therapeutic strategies for a significant fraction of patients. Therefore, mutation-independent therapeutic strategies, acting on common pathways that underly retinal damage, are gaining interest as complementary/alternative approaches for retinal diseases. This review will provide an overview of mutation-independent strategies that rely on the modulation in the retina of key genes regulating such crucial degenerative pathways. In particular, we will describe how gene-based approaches explore the use of neurotrophic factors, microRNAs (miRNAs), genome editing and optogenetics in order to restore/prolong visual function in both outer and inner retinal diseases. We predict that the exploitation of gene delivery procedures applied to mutation/gene independent approaches may provide the answer to the unmet therapeutic need of a large fraction of patients with genetically heterogeneous and complex retinal diseases.

Correlation Between SNPs at the 3'UTR of the FGF2 Gene and Their Interaction with Environmental Factors in Han Chinese Diabetic Peripheral Neuropathy Patients

FGF2 is a neurotrophic factor that can act as a key regulatory molecule of neuroprotection, neurogenesis, and angiogenesis in various injuries. To explore the genetic background of the FGF2 gene on DPN development, this study analyzed the correlation between SNPs in the 3'UTR of the FGF2 gene and their interaction with environmental factors in DPN patients of Han Chinese nationality. Sanger sequencing was used to analyze the FGF2 genotypes at the rs1048201, rs3804158, rs41348645, rs6854081, rs3747676, rs7683093, rs1476215, and rs1476217 loci in 150 DPN patients, 150 NDPN patients, and 150 healthy control patients. Plasma FGF2 levels were measured in all subjects by using ELISAs. Subjects carrying the T allele at the rs1048201 locus in the FGF2 gene had a significantly lower risk of developing DPN compared with subjects carrying the C allele (OR = 0.43, 95% CI = 0.33-0.56, p < 0.01). Subjects with the G genotype at the rs6854081 locus had an exceptionally higher risk of developing DPN than subjects with the T allele (OR = 1.66, 95% CI = 1.39-1.89, p < 0.01). Individuals harboring the G allele at the rs7683093 locus had a markedly higher risk of DPN than patients with the C allele (OR = 1.63, 95% CI = 1.36-1.87, p < 0.01). Finally, individuals having the A genotype at the rs1476215 locus had a significantly higher risk of DPN than individuals carrying the T allele (OR = 1.82, 95% CI = 1.53-2.02, p < 0.01). There was an interaction between age and alcohol consumption and the SNP rs7683093. SNPs at rs1048201, rs6854081, rs7683093, and rs1476215 in the FGF2 3'UTR were strongly associated with plasma levels of FGF2 (p < 0.05). SNPs at the rs1048201, rs6854081, rs7683093, and rs1476215 loci in the FGF2 gene were significantly associated with the risk of DPN. A possible mechanism is that these SNPs affect the expression level of FGF2 by interrupting the binding of microRNAs to target sites in the 3'UTR.

Characterization, Stability, and in Vivo Efficacy Studies of Recombinant Human CNTF and Its Permeation into the Neural Retina in ex Vivo Organotypic Retinal Explant Culture Models

Ciliary neurotrophic factor (CNTF) is one of the most studied neuroprotective agents with acknowledged potential in treating diseases of the posterior eye segment. Although its efficacy and mechanisms of action in the retina have been studied extensively, it is still not comprehensively understood which retinal cells mediate the therapeutic effects of CNTF. As with therapeutic proteins in general, it is poorly elucidated whether exogenous CNTF administered into the vitreous can enter and distribute into the retina and hence reach potentially responsive target cells. Here, we have characterized our purified recombinant human CNTF (rhCNTF), studied the protein’s in vitro bioactivity in a cell-based assay, and evaluated the thermodynamic and oligomeric status of the protein during storage. Biological activity of rhCNTF was further evaluated in vivo in an animal model of retinal degeneration. The retinal penetration and distribution of rhCNTF after 24 h was studied utilizing two ex vivo retina models. Based on our characterization findings, our rhCNTF is correctly folded and biologically active. Moreover, based on initial screening and subsequent follow-up, we identified two buffers in which rhCNTF retains its stability during storage. Whereas rhCNTF did not show photoreceptor preservative effect or improve the function of photoreceptors in vivo, this could possibly be due to the used disease model or the short duration of action with a single intravitreal injection of rhCNTF. On the other hand, the lack of in vivo efficacy was shown to not be due to distribution limitations; permeation into the retina was observed in both retinal explant models as in 24 h rhCNTF penetrated the inner limiting membrane, and being mostly observed in the ganglion cell layer, distributed to different layers of the neural retina. As rhCNTF can reach deeper retinal layers, in general, having direct effects on resident CNTF-responsive target cells is plausible.

Has retinal gene therapy come of age? From bench to bedside and back to bench

Retinal gene therapy has advanced considerably in the past three decades. Initial efforts have been devoted to comprehensively explore and optimize the transduction abilities of gene delivery vectors, define the appropriate intraocular administration routes and obtain evidence of efficacy in animal models of inherited retinal diseases (IRDs). Successful translation in clinical trials of the initial promising proof-of-concept studies led to the important milestone of the first approved product for retinal gene therapy in both US and Europe. The unprecedented clinical development observed during the last decade in the field is however highlighting new challenges that will need to be overcome to bring gene therapy to fruition to a larger patient population within and beyond the realm of IRDs.

Molecular Mechanisms Mediating Diabetic Retinal Neurodegeneration: Potential Research Avenues and Therapeutic Targets

Diabetic retinopathy (DR) is a devastating complication of diabetes with a prevalence rate of 35%, and no effective treatment options. Since the most visible clinical features of DR are microvascular irregularities, therapeutic interventions often attempt to reduce microvascular injury, but only after permanent retinal damage has ensued. However, recent data suggests that diabetes initially affects retinal neurons, leading to neurodegeneration as an early occurrence in DR, before onset of the more noticeable vascular abnormalities. In this review, we delineate the sequence of initiating events leading to retinal degeneration in DR, considering neuronal dysfunction as a primary event. Key molecular mechanisms and potential biomarkers associated with retinal neuronal degeneration in diabetes are discussed. In addition to glial reactivity and inflammation in the diabetic retina, the contribution of neurotrophic factors, cell adhesion molecules, apoptosis markers, and G protein signaling to neurodegenerative pathways warrants further investigation. These studies could complement recent developments in innovative treatment strategies for diabetic retinopathy, such as targeting retinal neuroprotection, promoting neuronal regeneration, and attempts to re-program other retinal cell types into functional neurons. Indeed, several ongoing clinical trials are currently attempting treatment of retinal neurodegeneration by means of such novel therapeutic avenues. The aim of this article is to highlight the crucial role of neurodegeneration in early retinopathy progression, and to review the molecular basis of neuronal dysfunction as a first step toward developing early therapeutic interventions that can prevent permanent retinal damage in diabetes. ClinicalTrials.gov: NCT02471651, NCT01492400.

Neonatal systemic inflammation and the risk of low scores on measures of reading and mathematics achievement at age 10 years among children born extremely preterm

BACKGROUND

Difficulties with reading and math occur more commonly among children born extremely preterm than among children born at term. Reasons for this are unclear.

METHODS

We measured the concentrations of 27 inflammatory-related and neurotrophic/angiogenic proteins (angio-neurotrophic proteins) in multiple blood specimens collected a week apart during the first postnatal month from 660 children born before the 28th week of gestation who at age 10 years had an IQ ≥ 70 and a Wechsler Individual Achievement Test 3rd edition (WIAT-III) assessment. We identified four groups of children, those who had a Z-score ≤ -1 on the Word Reading assessment only, on the Numerical Operations assessment only, on both of these assessments, and on neither, which served as the referent group. We then modeled the risk of each learning limitation associated with a top quartile concentration of each protein, and with high and lower concentrations of multiple proteins.

RESULTS

The protein profile of low reading scores was confined to the third and fourth postnatal weeks when increased risks were associated with high concentrations of IL-8 and ICAM-1 in the presence of low concentrations of angio-neurotrophic proteins. The profile of low math scores was very similar, except it did not include ICAM-1. In contrast, the profile of low scores on both assessments was present in each of the first four postnatal weeks. The increased risks associated with high concentrations of TNF-α in the first two weeks and of IL-8 and ICAM-1 in the next two weeks were modulated down by high concentrations of angio-neurotrophic proteins.

CONCLUSIONS

High concentrations of angio-neurotrophic proteins appear to reduce/moderate the risk of each learning limitation associated with systemic inflammation. The three categories of limitations have protein profiles with some similarities, and yet some differences, too.

Neuroprotection by (endo)Cannabinoids in Glaucoma and Retinal Neurodegenerative Diseases

BACKGROUND

Emerging neuroprotective strategies are being explored to preserve the retina from degeneration, that occurs in eye pathologies like glaucoma, diabetic retinopathy, age-related macular degeneration, and retinitis pigmentosa. Incidentally, neuroprotection of retina is a defending mechanism designed to prevent or delay neuronal cell death, and to maintain neural function following an initial insult, thus avoiding loss of vision.

METHODS

Numerous studies have investigated potential neuroprotective properties of plant-derived phytocannabinoids, as well as of their endogenous counterparts collectively termed endocannabinoids (eCBs), in several degenerative diseases of the retina. eCBs are a group of neuromodulators that, mainly by activating G protein-coupled type-1 and type-2 cannabinoid (CB1 and CB2) receptors, trigger multiple signal transduction cascades that modulate central and peripheral cell functions. A fine balance between biosynthetic and degrading enzymes that control the right concentration of eCBs has been shown to provide neuroprotection in traumatic, ischemic, inflammatory and neurotoxic damage of the brain.

RESULTS

Since the existence of eCBs and their binding receptors was documented in the retina of numerous species (from fishes to primates), their involvement in the visual processing has been demonstrated, more recently with a focus on retinal neurodegeneration and neuroprotection.

CONCLUSION

The aim of this review is to present a modern view of the endocannabinoid system, in order to discuss in a better perspective available data from preclinical studies on the use of eCBs as new neuroprotective agents, potentially useful to prevent glaucoma and retinal neurodegenerative diseases.

The Pathway From Genes to Gene Therapy in Glaucoma: A Review of Possibilities for Using Genes as Glaucoma Drugs

Treatment of diseases with gene therapy is advancing rapidly. The use of gene therapy has expanded from the original concept of re-placing the mutated gene causing the disease to the use of genes to con-trol nonphysiological levels of expression or to modify pathways known to affect the disease. Genes offer numerous advantages over conventional drugs. They have longer duration of action and are more specific. Genes can be delivered to the target site by naked DNA, cells, nonviral, and viral vectors. The enormous progress of the past decade in molecular bi-ology and delivery systems has provided ways for targeting genes to the intended cell/tissue and safe, long-term vectors. The eye is an ideal organ for gene therapy. It is easily accessible and it is an immune-privileged site. Currently, there are clinical trials for diseases affecting practically every tissue of the eye, including those to restore vision in patients with Leber congenital amaurosis. However, the number of eye trials compared with those for systemic diseases is quite low (1.8%). Nevertheless, judg-ing by the vast amount of ongoing preclinical studies, it is expected that such number will increase considerably in the near future. One area of great need for eye gene therapy is glaucoma, where a long-term gene drug would eliminate daily applications and compliance issues. Here, we review the current state of gene therapy for glaucoma and the possibilities for treating the trabecular meshwork to lower intraocular pressure and the retinal ganglion cells to protect them from neurodegeneration.

Modulation of Type-1 and Type-2 Cannabinoid Receptors by Saffron in a Rat Model of Retinal Neurodegeneration

Experimental studies demonstrated that saffron (Crocus sativus) given as a dietary supplement counteracts the effects of bright continuous light (BCL) exposure in the albino rat retina, preserving both morphology and function and probably acting as a regulator of programmed cell death [1]. The purpose of this study was to ascertain whether the neuroprotective effect of saffron on rat retina exposed to BCL is associated with a modulation of the endocannabinoid system (ECS). To this aim, we used eight experimental groups of Sprague-Dawley rats, of which six were exposed to BCL for 24 hours. Following retinal function evaluation, retinas were quickly removed for biochemical and morphological analyses. Rats were either saffron-prefed or intravitreally injected with selective type-1 (CB1) or type-2 (CB2) cannabinoid receptor antagonists before BCL. Prefeeding and intravitreally injections were combined in two experimental groups before BCL. BCL exposure led to enhanced gene and protein expression of retinal CB1 and CB2 without affecting the other ECS elements. This effect of BCL on CB1 and CB2 was reversed by saffron treatment. Selective CB1 and CB2 antagonists reduced photoreceptor death, preserved morphology and visual function of retina, and mitigated the outer nuclear layer (ONL) damage due to BCL. Of interest, CB2-dependent neuroprotection was more pronounced than that conferred by CB1. These data suggest that BCL modulates only distinct ECS elements like CB1 and CB2, and that saffron and cannabinoid receptors could share the same mechanism in order to afford retinal protection.

Olfactory ecto-mesenchymal stem cells possess immunoregulatory function and suppress autoimmune arthritis

Recent studies have identified olfactory ecto-mesenchymal stem cells (OE-MSCs) as a new type of resident stem cell in the olfactory lamina propria. However, it remains unclear whether OE-MSCs possess any immunoregulatory functions. In this study, we found that mouse OE-MSCs expressed higher transforming growth factor-beta and interleukin-10 levels than bone marrow-derived MSCs. In culture, OE-MSCs exerted their immunosuppressive capacity via directly suppressing effector T-cell proliferation and increasing regulatory T (Treg) cell expansion. In mice with collagen-induced arthritis, adoptive transfer of OE-MSCs markedly suppressed arthritis onset and disease severity, which was accompanied by increased Treg cells and reduced Th1/Th17 cell responses in vivo. Taken together, our findings identified a novel function of OE-MSCs in regulating T-cell responses, indicating that OE-MSCs may represent a new cell therapy for the treatment of rheumatoid arthritis and other autoimmune diseases.

Sustained Neural Stem Cell-Based Intraocular Delivery of CNTF Attenuates Photoreceptor Loss in the nclf Mouse Model of Neuronal Ceroid Lipofuscinosis

A sustained intraocular administration of neurotrophic factors is among the strategies aimed at establishing treatments for currently untreatable degenerative retinal disorders. In the present study we have analyzed the neuroprotective effects of a continuous neural stem (NS) cell-based intraocular delivery of ciliary neurotrophic factor (CNTF) on photoreceptor cells in the nclf mouse, an animal model of the neurodegenerative lysosomal storage disorder variant late infantile neuronal ceroid lipofuscinosis (vLINCL). To this aim, we genetically modified adherently cultivated NS cells with a polycistronic lentiviral vector encoding a secretable variant of CNTF together with a Venus reporter gene (CNTF-NS cells). NS cells for control experiments (control-NS cells) were modified with a vector encoding the reporter gene tdTomato. Clonal CNTF-NS and control-NS cell lines were established using fluorescent activated cell sorting and intravitreally grafted into 14 days old nclf mice at the onset of retinal degeneration. The grafted cells preferentially differentiated into astrocytes that were attached to the posterior side of the lenses and the vitreal side of the retinas and stably expressed the transgenes for at least six weeks, the latest post-transplantation time point analyzed. Integration of donor cells into host retinas, ongoing proliferation of grafted cells or adverse effects of the donor cells on the morphology of the host eyes were not observed. Quantitative analyses of host retinas two, four and six weeks after cell transplantation revealed the presence of significantly more photoreceptor cells in eyes with grafted CNTF-NS cells than in eyes with grafted control-NS cells. This is the first demonstration that a continuous intraocular administration of a neurotrophic factor attenuates retinal degeneration in an animal model of neuronal ceroid lipofuscinosis.

Status and perspectives of neuroprotective therapies in glaucoma: the European Glaucoma Society White Paper

Glaucoma, a chronic progressive neuropathy and the most frequent cause of irreversible blindness worldwide, is commonly treated by medication or surgery aimed at lowering intraocular pressure. In view of the limited therapeutic options, the European Glaucoma Society (EGS) sponsored two Think Tank Meetings with the goal of assessing the current status and the overall perspectives for neuroprotective treatment strategies in glaucoma. The results of the meetings are summarized in this EGS White Paper.