Oxidative stress (OS) refers to an imbalance between free radicals (FRs), namely highly reactive molecules normally generated in our body by several pathways, and intrinsic antioxidant capacity. When FR levels overwhelm intrinsic antioxidant defenses, OS occurs, inducing a series of downstream chemical reactions. Both reactive oxygen species (ROS) and reactive nitrogen species (RNS) are produced by numerous chemical reactions that take place in tissues and organs and are then eliminated by antioxidant molecules. In particular, the scientific literature focuses more on ROS participation in the pathogenesis of diseases than on the role played by RNS. By its very nature, the eye is highly exposed to ultraviolet radiation (UVR), which is directly responsible for increased OS. In this review, we aimed to focus on the retinal damage caused by ROS/RNS and the related retinal pathologies. A deeper understanding of the role of oxidative and nitrosative stress in retinal damage is needed in order to develop targeted therapeutic interventions to slow these pathologies.

The present review focuses on recent clinical trials that analyze the efficacy of intravitreal therapeutic agents for the treatment of dry age-related macular degeneration (AMD), such as neuroprotective drugs, and complement inhibitors, also called immunomodulatory or anti-inflammatory agents. A systematic literature search was performed to identify randomized controlled trials published prior to January 2019. Patients affected by dry AMD treated with intravitreal therapeutic agents were included. Changes in the correct visual acuity and reduction in geographic atrophy progression were evaluated. Several new drugs have shown promising results, including those targeting the complement cascade and neuroprotective agents. The potential action of the two groups of drugs is to block complement cascade upregulation of immunomodulating agents, and to prevent the degeneration and apoptosis of ganglion cells for the neuroprotectors, respectively. Our analysis indicates that finding treatments for dry AMD will require continued collaboration among researchers to identify additional molecular targets and to fully interrogate the utility of pluripotent stem cells for personalized therapy.

To evaluate whether grafting of autologous mesenchymal cells, adipose-derived stem cells, and platelet-rich plasma into the supracoroideal space by surgical treatment with the Limoli retinal restoration technique (LRRT) can exert a beneficial effect in retinitis pigmentosa (RP) patients. Twenty-one eyes underwent surgery and were divided based on retinal foveal thickness (FT) ≤ 190 or > 190 µm into group A-FT and group B-FT, respectively. The specific LRRT triad was grafted in a deep scleral pocket above the choroid of each eye. At 6-month follow-up, group B showed a non-significant improvement in residual close-up visus and sensitivity at microperimetry compared to group A. After an in-depth review of molecular biology studies concerning degenerative phenomena underlying the etiopathogenesis of retinitis pigmentosa (RP), it was concluded that further research is needed on tapeto-retinal degenerations, both from a clinical and molecular point of view, to obtain better functional results. In particular, it is necessary to increase the number of patients, extend observation timeframes, and treat subjects in the presence of still trophic retinal tissue to allow adequate biochemical and functional catering.

Background: Glaucomatous optic neuropathy (GON) is an anatomofunctional impairment of the optic nerve triggered by glaucoma. Recently, growth factors (GFs) have been shown to produce retinal neuroenhancement. The suprachoroidal autograft of mesenchymal stem cells (MSCs) by the Limoli retinal restoration technique (LRRT) has proven to achieve retinal neuroenhancement by producing GF directly into the choroidal space. This retrospectively registered clinical study investigated the visual function changes in patients with GON treated with LRRT. Methods: Twenty-five patients (35 eyes) with GON in progressive disease conditions were included in the study. Each patient underwent a comprehensive ocular examination, including the analysis of best corrected visual acuity (BCVA) for far and near visus, sensitivity by Maia microperimetry, and the study of the spectral domain-optical coherence tomography (SD-OCT). The patients were divided into two groups: a control group, consisting of 21 eyes (average age 72.2 years, range 50–83), and an LRRT group, consisting of 14 eyes (average age 67.4, range 50–84). Results: After 6 months, the BCVA, close-up visus, and microperimetric sensitivity significantly improved in the LRRT-treated group (p0.5). Conclusions: Patients with GON treated with LRRT showed a significant increase in visual performance (VP) both in BCVA and sensitivity and an improvement of residual close-up visus, in the comparison between the LRRT results and the control group. Further studies will be needed to establish the actual significance of the reported findings.

Purpose: To assess whether treatment with the Limoli Retinal Restoration Technique (LRRT) can be performed in patients with retinitis pigmentosa (RP), grafting the autologous cells in a deep scleral pocket above the choroid of each eye to exert their beneficial effect on the residual retinal cells. Methods: The patients were subjected to a complete ophthalmological examination, including best corrected visual acuity (BCVA), close-up visus measurements, spectral domain-optical coherence tomography (SD-OCT), microperimetry (MY), and electroretinography (ERG). Furthermore, the complete ophthalmological examination was carried out at baseline (T0) and at 6 months (T180) after surgery. The Shapiro–Wilk test was used to assess the normality of distribution of the investigated parameters. A mixed linear regression model was used to analyse the difference in all the studied parameters at T0 and T180, and to compare the mean change between the two groups. All statistical analyses were performed with STATA 14.0 (Collage Station, Texas, USA). Results: LRRT treatment was performed in 34 eyes of 25 RP patients recruited for the study. The eyes were classified in two groups on the basis of foveal thickness (FT) assessed by SD-OCT: 14 eyes in Group A (FT≤190 μm) and the remaining 20 ones in Group B (FT > 190 μm). Although it had not reached the statistical significance, Group B showed a better improvement in BCVA, residual close-up visus and sensitivity than Group A. Conclusions: Previous studies have described the role of LRRT in slowing down retinal degenerative diseases. Consequently, this surgical procedure could improve the clinical and rehabilitative prognostic parameters in RP patients. On the other hand, further clinical research and studies with longer follow-up will be needed to evaluate its efficacy.

Both tissue repair and regeneration are a priority in regenerative medicine. Retinitis pigmentosa (RP), a complex retinal disease characterized by the progressive loss of impaired photoreceptors, is currently lacking effective therapies: this represents one of the greatest challenges in the field of ophthalmological research. Although this inherited retinal dystrophy is still an incurable genetic disease, the oxidative damage is an important pathogenetic element that may represent a viable target of therapy. In this review, we summarize the current neuroscientific evidence regarding the effectiveness of cell therapies in RP, especially those based on mesenchymal cells, and we focus on their therapeutic action: limitation of both oxidative stress and apoptotic processes triggered by the disease and promotion of cell survival. Cell therapy could therefore represent a feasible therapeutic option in RP.