PRIMA subretinal wireless photovoltaic microchip implantation in non-human primate and feline models

PURPOSE: To evaluate the surgical technique for subretinal implantation of two sizes of PRIMA photovoltaic wireless microchip in two animal models, and refine these surgical procedures for human trials. METHODS: Cats and Macaca fascicularis primates with healthy retina underwent vitrectomy surgery and were implanted with subretinal wireless photovoltaic microchip at the macula/central retina. The 1.5mm PRIMA chip was initially studied in feline eyes. PRIMA implant (2mm,1.5mm sizes) arrays were studied in primates. Feasibility of subretinal chip implantation was evaluated with a newly-developed surgical technique, with surgical complications and adverse events recorded. RESULTS: The 1.5mm implant was placed in the central retina of 11 feline eyes, with implantation duration 43-106 days. The 1.5mm implant was correctly positioned into central macula of 11 primate eyes, with follow-up periods of minimum 6 weeks (n = 11), 2 years (n = 2), and one eye for 3 years. One primate eye underwent multi-chip 1.5mm implantation using two 1.5mm chips. The 2mm implant was delivered to 4 primate eyes. Optical coherence tomography confirmed correct surgical placement of photovoltaic arrays in the subretinal space in all 26 eyes. Intraoperative complications in primate eyes included retinal tear, macular hole, retinal detachment, and vitreous hemorrhage that resolved spontaneously. Postoperatively, there was no case of significant ocular inflammation in the 1.5mm implant group. CONCLUSIONS: We report subretinal implantation of 1.5mm and 2mm photovoltaic arrays in the central retina of feline and central macula of primate eyes with a low rate of device-related complications. The in vivo PRIMA implantation technique has been developed and refined for use for a 2mm PRIMA implant in ongoing human trials

PRIMA subretinal wireless photovoltaic microchip implantation in non-human primate and feline models

Purpose To evaluate the surgical technique for subretinal implantation of two sizes of PRIMA photovoltaic wireless microchip in two animal models, and refine these surgical procedures for human trials. Methods Cats and Macaca fascicularis primates with healthy retina underwent vitrectomy surgery and were implanted with subretinal wireless photovoltaic microchip at the macula/central retina. The 1.5mm PRIMA chip was initially studied in feline eyes. PRIMA implant (2mm,1.5mm sizes) arrays were studied in primates. Feasibility of subretinal chip implantation was evaluated with a newly-developed surgical technique, with surgical complications and adverse events recorded. Results The 1.5mm implant was placed in the central retina of 11 feline eyes, with implantation duration 43-106 days. The 1.5mm implant was correctly positioned into central macula of 11 primate eyes, with follow-up periods of minimum 6 weeks (n = 11), 2 years (n = 2), and one eye for 3 years. One primate eye underwent multi-chip 1.5mm implantation using two 1.5mm chips. The 2mm implant was delivered to 4 primate eyes. Optical coherence tomography confirmed correct surgical placement of photovoltaic arrays in the subretinal space in all 26 eyes. Intraoperative complications in primate eyes included retinal tear, macular hole, retinal detachment, and vitreous hemorrhage that resolved spontaneously. Postoperatively, there was no case of significant ocular inflammation in the 1.5mm implant group. Conclusions We report subretinal implantation of 1.5mm and 2mm photovoltaic arrays in the central retina of feline and central macula of primate eyes with a low rate of device-related complications. The in vivo PRIMA implantation technique has been developed and refined for use for a 2mm PRIMA implant in ongoing human trials

Translational considerations in injectable cell-based therapeutics for neurological applications: concepts, progress and challenges

Significant progress has been made during the past decade towards the clinical adoption of cell-based therapeutics. However, existing cell-delivery approaches have shown limited success, with numerous studies showing fewer than 5% of injected cells persisting at the site of injection within days of transplantation. Although consideration is being increasingly given to clinical trial design, little emphasis has been given to tools and protocols used to administer cells. The different behaviours of various cell types, dosing accuracy, precise delivery, and cell retention and viability post-injection are some of the obstacles facing clinical translation. For efficient injectable cell transplantation, accurate characterisation of cellular health post-injection and the development of standardised administration protocols are required. This review provides an overview of the challenges facing effective delivery of cell therapies, examines key studies that have been carried out to investigate injectable cell delivery, and outlines opportunities for translating these findings into more effective cell-therapy interventions

A nova grande promessa da inovação em fármacos: RNA interferência saindo do laboratório para a clínica

A descoberta de que nossas células dispõem de um mecanismo de silenciamento gênico empregando RNA interferência ainda é muito recente. Apesar disso, em menos de uma década a investigação científica já alcançou progresso, suficiente para muito brevemente nos apropriarmos desse conhecimento com fins terapêuticos. Duplexes de RNA são potenciais fármacos e há investimentos altos nessa nova abordagem. Aparentemente, a promessa de terapia gênica parece finalmente atingir sua maturidade com essas novas ferramentas.<br>The discovery of gene silencing mechanisms in our own cells using RNA interference is very recent. However, in less than a decade, the scientific investigation have progressed enough to make us see that, very soon, we will use this knowledge for therapeutic purposes. RNA duplexes are potential pharmaceutical drugs and there are high investments in this new strategy. The promising gene therapy seems to finally reach maturity with these new tools

Correlation of multimodal imaging in sickle cell retinopathy

Purpose: To correlate macular findings on spectral domain optical coherence tomography (SDOCT) and optical coherence tomography angiography (OCTA) with quantitative ischemic index calculations on ultra-wide-field fluorescein angiography (UWFFA) in patients with sickle cell retinopathy. Methods: In this retrospective case series, SDOCT, OCTA, and UWFFA images of patients with sickle cell retinopathy were evaluated. Eyes were staged based on the Goldberg classification of proliferative sickle cell retinopathy. Focal areas of macular thinning were assessed on SDOCT, macular vessel density was derived from OCTA, and peripheral ischemic index was calculated from UWFFA. Results: Eighteen eyes of 10 patients were included. Mean age was 36.8 ± 16.8 years, and 6 patients (11 eyes) were SS, 3 patients (5 eyes) were SC, and 1 patient (2 eyes) was Sb thalassemia in hemoglobin electrophoresis. Abnormal macular findings included inner retinal atrophy in 11 eyes (61) on SDOCT, vascular remodeling and nonperfusion in the superficial and deep retinal capillary plexus in 12 eyes (67) on OCTA, and macular microvascular abnormalities in 9 eyes (50) on UWFFA. Sickle cell retinopathy Stage I was identified in 4 eyes (22.2), Stage II in 8 eyes (44.4), and Stage III in 6 eyes (33.3). Mean ischemic index was 14.1 ± 9.1. Ischemic index was significantly correlated with hemoglobinopathy subtype (23.7 ± 9.8, 9.3 ± 5.4, and 16.3 ± 3.2, for SC, SS, and Sb thalassemia disease, respectively), stage of sickle cell retinopathy (22.5 ± 9.2, 12.5 ± 4.9, and 4.5 ± 0.73 for Stages III, II, and I, respectively), and presence of retinal thinning on SDOCT (17.4 ± 9.7 vs. 8.8 ± 5.1, respectively). Conclusion: Multimodal imaging can provide a more complete description of the microvascular and structural alterations associated with sickle retinopathy. The correlation between the severity of peripheral nonperfusion and stage and subtype of retinopathy suggests that UWF imaging may be a useful tool in the evaluation of these patients