Control of retinal progenitor cell (RPC) survival, delivery, and differentiation following transplantation into the retina remains a challenge. This is largely due to the use of culture systems that involve poorly defined animal products and do not mimic the natural developmental milieu. We describe the use of hyaluronic acid (HA) based hydrogels to encapsulate mouse RPCs and a delivery system for injectable tissue engineering. We selected HA because of its role in early development and as a feeder layer in stem cell cultures, and the relative ease with which various parameters can be controlled (e.g., hydrogel architecture, mechanics, and degradation). When encapsulated in three-dimensional HA hydrogels, RPCs maintained their undifferentiated state and readily formed neurospheres. These hydrogels were viscous solutions, exhibiting properties ideal for delivery to a subretinal space. The transplants caused very little disruption to the host retinal architecture. Hydrogels were completely degraded and RPCs distributed evenly in the subretinal space by week 3 and expressed the mature photoreceptor marker recoverin. HA hydrogels, with their developmentally relevant composition and malleable physical properties, provide a unique microenvironment for self renewal and differentiation of RPCs for retinal repair.

Objectives: To evaluate the long‐term biosafety and efficacy of transplantation of human embryonic stem cells‐derived retinal pigment epithelial (hESC‐RPE) cells in early‐stage of Stargardt macular degeneration (STGD1).Materials and methods: Seven patients participated in this prospective clinical study, where they underwent a single subretinal transplantation of 1 × 10⁵ hESC‐RPE cells in one eye, whereas the fellow eye served as control. These patients were reassessed for a 60‐month follow‐up through systemic and ophthalmic examinations.Results: None of the patients experienced adverse reactions systemically or locally, except for two who had transiently high intraocular pressure post‐operation. Functional assessments demonstrated that all of the seven operated eyes had transiently increased or stable visual function 1‐4 months after transplantation. At the last follow‐up visit, two of the seven eyes showed visual function loss than the baseline; however, one of them showed a stable visual acuity when compared with the change of fellow eye. Obvious small high reflective foci in the RPE layer were displayed after the transplantation, and maintained until the last visit. Interestingly, three categories of patients who were classified based on autofluorescence, exhibited distinctive patterns of morphological and functional change.Conclusions: Subretinal transplantation of hESC‐RPE in early‐stage STGD1 is safe and tolerated in the long term. Further investigation is needed for choosing proper subjects according to the multi‐model image and function assessments.

Retinitis pigmentosa (RP) is a hereditary retinal degeneration disease with no effective therapeutic approaches. Inflammatory and immune disorders are thought to play an important role in the pathogenesis of RP. Human umbilical cord mesenchymal stem cells (UCMSCs), with multiple biological functions such as anti-inflammation and immunoregulation, have been applied in different systemic diseases. We conducted a phase I/II clinical trial aiming to evaluate the safety and efficacy of intravenous administration of UCMSCs in advanced RP patients. All 32 subjects were intravenously infused with one dose of 10⁸ UCMSCs and were followed up for 12 months. No serious local or systemic adverse effects occurred in the whole follow-up. Most patients improved their best corrected visual acuity (BCVA) in the first 3 months. The proportions of patients with improved or maintained BCVA were 96.9%, 95.3%, 93.8%, 95.4%, 90.6%, and 90.6% at the 1st, 2nd, 3rd, 6th, 9th, and 12th month follow-up, respectively. Most of the patients (81.3%) maintained or improved their visual acuities for 12 months. The average NEI VFQ-25 questionnaire scores were significantly improved at the third month (P < 0.05). The average visual field sensitivity and flash visual evoked potential showed no significant difference (P = 0.185, P = 0.711). Our results indicated that the intravenous infusion of UCMSCs was safe for advanced RP patients. Most of the patients improved or maintained their visual functions in a long term. The life qualities were improved significantly in the first 3 months, suggesting that the intravenous infusion of UCMSCs may be a promising therapeutic approach for advanced RP patients.

Background: Insufficient clearance by microglial cells, prevalent in several neurological conditions and diseases, is intricately intertwined with MFG-E8 expression and inflammatory responses. Electromagnetic field (EMF) exposure can elicit the pro-inflammatory activation and may also trigger an alteration of the clearance function in microglial cells. Curcumin has important roles in the anti-inflammatory and phagocytic process. Here, we evaluated the ability of curcumin to ameliorate the phagocytic ability of EMF-exposed microglial cells (N9 cells) and documented relative pathways. Methods: N9 cells were pretreated with or without recombinant murine MFG-E8 (rmMFG-E8), curcumin and an antibody of toll-like receptor 4 (anti-TLR4), and subsequently treated with EMF or a sham exposure. Their phagocytic ability was evaluated using phosphatidylserine-containing fluorescent bioparticles. The pro-inflammatory activation of microglia was assessed via CD11b immunoreactivity and the production of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) and nitric oxide (NO) via the enzyme-linked immunosorbent assay or the Griess test. We evaluated the ability of curcumin to ameliorate the phagocytic ability of EMF-exposed N9 cells, including checking the expression of MFG-E8, α_vβ₃ integrin, TLR4, nuclear factor-κB (NF-κB) and signal transducer and activator of transcription 3 (STAT3) using Western blotting. Results: EMF exposure dramatically enhanced the expression of CD11b and depressed the phagocytic ability of N9 cells. rmMFG-E8 could clearly ameliorate the phagocytic ability of N9 cells after EMF exposure. We also found that EMF exposure significantly increased the secretion of pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β) and the production of NO; however, these increases were efficiently chilled by the addition of curcumin to the culture medium. This reduction led to the amelioration of the phagocytic ability of EMF-exposed N9 cells. Western blot analysis revealed that curcumin and naloxone restored the expression of MFG-E8 but had no effect on TLR4 and cytosolic STAT3. Moreover, curcumin significantly reduced the expression of NF-κB p65 in nuclei and phospho-STAT3 (p-STAT3) in cytosols and nuclei. Conclusions: This study indicates that curcumin ameliorates the depressed MFG-E8 expression and the attenuated phagocytic ability of EMF-exposed N9 cells, which is attributable to the inhibition of the pro-inflammatory response through the NF-κB and STAT3 pathways.

Stem cell transplantation shows enormous potential for treatment of incurable retinal degeneration (RD). To determine if and how grafts connect with the neural circuits of the advanced degenerative retina (ADR) and improve vision, we perform calcium imaging of GCaMP5-positive grafts in retinal slices. The organoid-derived C-Kit⁺/SSEA1^- (C-Kit⁺) retinal progenitor cells (RPCs) become synaptically organized and build spontaneously active synaptic networks in three major layers of ADR. Light stimulation of the host photoreceptors elicits distinct neuronal responses throughout the graft RPCs. The graft RPCs and their differentiated offspring cells in inner nuclear layer synchronize their activities with the host cells and exhibit presynaptic calcium flux patterns that resemble intact retinal neurons. Once graft-to-host network is established, progressive vision loss is stabilized while control eyes continually lose vision. Therefore, transplantation of organoid-derived C-Kit⁺ RPCs can form functional synaptic networks within ADR and it holds promising avenue for advanced RD treatment.

Cerebral venous sinus thrombosis or stenosis (here collectively referred to as cerebral venous sinus occlusion, CVSO) can cause chronically-elevated intracranial pressure (ICP). Patients may have no neurological symptoms other than visual impairment, secondary to bilateral papilledema. Correctly recognizing these conditions, through proper ophthalmological examination and brain imaging, is very important to avoid delayed diagnosis and treatment. We report a case series of 3 patients with chronic CVSO, who were admitted to an ophthalmological department in Chongqing, China, from 2015 March to 2017 February. All patients presented with decreased vision and bilateral papilledema, but had no headache or other neurological symptoms. The visual fields of all patients were impaired. Flash visual evoked potentials (VEPs) in two patients showed essentially normal peak time of P2 wave, and pattern VEPs in one patient displayed decreased P100 amplitude in one eye, while a normal P100 wave in the other eye. In all patients, lumbar puncture (LP) revealed significantly elevated ICP. And magnetic resonance venography (MRV) demonstrated cerebral venous sinus abnormalities in every patient: one right sigmoid sinus thrombosis, one superior sagittal sinus thrombosis, and one right transverse sinus stenosis. CVSO can cause chronically-elevated ICP, leading to bilateral papilledema and visual impairment. A considerable amount of patients have no apparent neurological symptoms other than visual loss. Unlike other optic nerve lesions, such as neuritis or ischemic optic neuropathy, the optic disc edema in CVSO is usually bilateral, the flash or pattern VEP is often normal or only mildly affected, and patients are often not sensitive to steroid therapy. CVSO should be suspected in such patients when unenhanced brain imaging is normal. Further investigations, such as LP and contrast-enhanced imaging (MRV and digital subtraction angiography), should be performed to diagnose or exclude CVSO.