Pluripotent stem cells: A therapeutic source for age-related macular degeneration

The impact of NF-κB on inflammatory and angiogenic processes in age-related macular degeneration

Age-related macular degeneration (AMD) is a prominent cause of vision loss, characterized by two different types, dry (atrophic) and wet (neovascular). Dry AMD is distinguished by the progressive deterioration of retinal cells, which ultimately causes a decline in vision. In contrast, wet AMD is defined by the abnormal development of blood vessels underneath the retina, leading to a sudden and severe vision impairment. The course of AMD is primarily driven by chronic inflammation and pathological angiogenesis, in which the NF-κB signaling pathway plays a crucial role. The activation of NF-κB results in the generation of pro-inflammatory cytokines, chemokines, and angiogenic factors like VEGF, which contribute to inflammation and the formation of new blood vessels in AMD. This review analyzes the intricate relationship between NF-κB signaling, inflammation, and angiogenesis in AMD and assesses the possibility of using NF-κB as a target for therapy. The evaluation involves a comprehensive examination of preclinical and clinical evidence that substantiates the effectiveness of NF-κB inhibitors in treating AMD by diminishing inflammation and pathological angiogenesis.

Predicting late-stage age-related macular degeneration by integrating marginally weak SNPs in GWA studies

Introduction: Age-related macular degeneration (AMD) is a progressive neurodegenerative disease and the leading cause of blindness in developed countries. Current genome-wide association studies (GWAS) for late-stage age-related macular degeneration are mainly single-marker-based approaches, which investigate one Single-Nucleotide Polymorphism (SNP) at a time and postpone the integration of inter-marker Linkage-disequilibrium (LD) information in the downstream fine mappings. Recent studies showed that directly incorporating inter-marker connection/correlation into variants detection can help discover novel marginally weak single-nucleotide polymorphisms, which are often missed in conventional genome-wide association studies, and can also help improve disease prediction accuracy. Methods: Single-marker analysis is performed first to detect marginally strong single-nucleotide polymorphisms. Then the whole-genome linkage-disequilibrium spectrum is explored and used to search for high-linkage-disequilibrium connected single-nucleotide polymorphism clusters for each strong single-nucleotide polymorphism detected. Marginally weak single-nucleotide polymorphisms are selected via a joint linear discriminant model with the detected single-nucleotide polymorphism clusters. Prediction is made based on the selected strong and weak single-nucleotide polymorphisms. Results: Several previously identified late-stage age-related macular degeneration susceptibility genes, for example, BTBD16, C3, CFH, CFHR3, HTARA1, are confirmed. Novel genes DENND1B, PLK5, ARHGAP45, and BAG6 are discovered as marginally weak signals. Overall prediction accuracy of 76.8% and 73.2% was achieved with and without the inclusion of the identified marginally weak signals, respectively. Conclusion: Marginally weak single-nucleotide polymorphisms, detected from integrating inter-marker linkage-disequilibrium information, may have strong predictive effects on age-related macular degeneration. Detecting and integrating such marginally weak signals can help with a better understanding of the underlying disease-development mechanisms for age-related macular degeneration and more accurate prognostics.

Tracking the Transplanted Neurosphere in Retinal Pigment Epithelium Degeneration Model

Introduction

Retinal Pigment Epithelium (RPE) layer deterioration is a leading cause of Age-Related Macular Degeneration (AMD), i.e., the most significant reason for irreversible blindness. The present study aimed to track the Neurosphere-Derived (NS) from Bone Marrow Stromal Stem Cells (BMSCs) grafted into the sub-retinal space (destruction of the RPE layer by sodium iodate).

Methods

RPE degeneration model was performed using the injection of 5% sodium iodate performed in the retro-orbital sinus of Wistar rats. BMSCs were extracted from the examined rat femur and induced into NS, using EGF, bFGF, and B27. BrdU-NS labeled cells were transplanted into the sub-retinal space. For detecting BMSCs and NS markers, immunocytochemistry was performed. Moreover, immunohistochemical was conducted for tracking the transplanted cells in the RPE and sensory retina.

Results

The immunocytochemistry of BMSCs cells displayed the expression of mesenchymal stem cells markers (CD90; 99%±1), CD166 (98%±2), CD44 (99%±1). Additionally, the expression of neural lineage markers in NS, such as SOX2, OCT4, Nanog, Nestin, and Neurofilaments (68, 160, 200) revealed the differentiation from BMSCs. Tracking BrdU-NS labeled suggested these aggregations in most layers of the retina.

Conclusion

Our study data indicated that BMSCs derived neurosphere had the potential to migrate in injured retinal and integrate into the neurosensory retina. These data can be useful in finding safe cells for replacement therapy in AMD.

Feasibility of intracerebrally administering multiple doses of genetically modified neural stem cells to locally produce chemotherapy in glioma patients

Neural stem cells (NSCs) are tumor tropic and can be genetically modified to produce anti-cancer therapies locally in the brain. In a prior first-in-human study we demonstrated that a single dose of intracerebrally administered allogeneic NSCs, which were retrovirally transduced to express cytosine deaminase (CD), tracked to glioma sites and converted oral 5-fluorocytosine (5-FC) to 5-fluorouracil (5-FU). The next step in the clinical development of this NSC-based anti-cancer strategy was to assess the feasibility of administering multiple intracerebral doses of CD-expressing NSCs (CD-NSCs) in patients with recurrent high grade gliomas. CD-NSCs were given every 2 weeks using an indwelling brain catheter, followed each time by a 7-day course of oral 5-FC (and leucovorin in the final patient cohort). Fifteen evaluable patients received a median of 4 (range 2–10) intracerebral CD-NSC doses; doses were escalated from 50 x 10⁶ to 150 x 10⁶ CD-NSCs. Neuropharmacokinetic data confirmed that CD-NSCs continuously produced 5-FU in the brain during the course of 5-FC. There were no clinical signs of immunogenicity, and only three patients developed anti-NSC antibodies. Our results suggest intracerebral administration of serial doses of CD-NSCs is safe and feasible and identified a recommended dose for phase II testing of 150 x 10⁶ CD-NSCs.

High efficient differentiation of human adipose-derived stem cells into retinal pigment epithelium-like cells in medium containing small molecules inducers with a simple method

BACKGROUND

The induction of retinal pigmented epithelium cells (RPE) is one of the most important objectives in research focused on treating retinal degenerative diseases. The present study aims to differentiate human adipose stem cells (hADSCs) into RPE cells for replacement therapies in cases of retinal degenerative diseases.

METHODS

Lipoaspirate-derived human adipose stem cells (LA-hADSCs) were obtained from abdominal samples and examined by immunocytochemistry for the expression of mesenchymal adipose stem cell markers. RPE cells were also obtained from human samples and cultured to be used as control after being examined for the expression of their designated markers. hADSCs differentiated into RPE cells after 80 days using chemical inducers in one steps. The differentiated cells were then compared to control cells in marker expression. The differentiated cells were also examined under a scanning electron microscope for the presence of apical microvilli and cell connection.

RESULTS

Cultured hADSCs at the fourth passage was shown to express the surface markers CD90 (98 ± 2%), CD11b (96 ± 3%), and CD105 (95 ± 4%). The RPE cells obtained from human samples expressed the marker RPE65 quite well. 80 days after differentiation, the previously hADSCs expressed both RPE65 (100%) and CRALBP (96 ± 1%) and were thus significantly similar to the RPE cells obtained from human samples. Morphologically, differentiated cells appeared to have epithelial and cytoplasmic pigment granules. Observations using a scanning electron microscope recorded clear connections among the differentiated RPE cells and revealed apical microvilli.

CONCLUSION

Human adipose stem cells can differentiate into retinal pigmented epithelium cells, which can be used in cell replacement therapy for degenerative diseases including age-related macular degeneration (AMD) as well as retinitis pigmentosa (RP).

Possibilities for Using Pluripotent Stem Cells for Restoring Damaged Eye Retinal Pigment Epithelium

The retinal pigment epithelium is a monolayer of pigmented, hexagonal cells connected by tight junctions. These cells compose part of the outer blood-retina barrier, protect the eye from excessive light, have important secretory functions, and support the function of photoreceptors, ensuring the coordination of a variety of regulatory mechanisms. It is the degeneration of the pigment epithelium that is the root cause of many retinal degenerative diseases. The search for reliable cell sources for the transplantation of retinal pigment epithelium is of extreme urgency. Pluripotent stem cells (embryonic stem or induced pluripotent) can be differentiated with high efficiency into the pigment epithelium of the retina, which opens up possibilities for cellular therapy in macular degeneration and can slow down the development of pathology and, perhaps, restore a patient's vision. Pioneering clinical trials on transplantation of retinal pigment epithelial cells differentiated from pluripotent stem cells in the United States and Japan confirmed the need for developing and optimizing such approaches to cell therapy. For effective use, pigment epithelial cells differentiated from pluripotent stem cells should have a set of functional properties characteristic of such cells in vivo. This review summarizes the current state of preclinical and clinical studies in the field of retinal pigment epithelial transplantation therapy. We also discuss different differentiation protocols based on data in the literature and our own data, and the problems holding back the widespread therapeutic application of retinal pigment epithelium differentiated from pluripotent stem cells.