Neuroprotection of Transplanting Human Umbilical Cord Mesenchymal Stem Cells in a Microbead Induced Ocular Hypertension Rat Model

Human adipose tissue-derived stem cell extracellular vesicles attenuate ocular hypertension-induced retinal ganglion cell damage by inhibiting microglia- TLR4/MAPK/NF-κB proinflammatory cascade signaling

Microglia-mediated neuroinflammatory responses are recognized as a predominant factor during high intraocular pressure (IOP)-induced retinal and optic nerve injury along with potential therapeutic targets for the disease. Our previous research indicated that mesenchymal stem cell (MSC) treatment could reduce high IOP-induced neuroinflammatory responses through the TLR4 pathway in a rat model without apparent cell replacement and differentiation, suggesting that the anti-neuroinflammatory properties of MSCs are potentially mediated by paracrine signaling. This study aimed to evaluate the anti-neuroinflammatory effect of human adipose tissue-derived extracellular vesicles (ADSC-EVs) in microbead-induced ocular hypertension (OHT) animals and to explore the underlying mechanism since extracellular vesicles (EVs) are the primary transporters for cell secretory action. The anti-neuroinflammatory effect of ADSC-EVs on LPS-stimulated BV-2 cells in vitro and OHT-induced retinal and optic nerve injury in vivo was investigated. According to the in vitro research, ADSC-EV treatment reduced LPS-induced microglial activation and the TLR4/NF-κB proinflammatory cascade response axis in BV-2 cells, such as CD68, iNOS, TNF-α, IL-6, and IL-1β, TLR4, p-38 MAPK, NF-κB. According to the in vivo data, intravitreal injection of ADSC-EVs promoted RGC survival and function, reduced microglial activation, microglial-derived neuroinflammatory responses, and TLR4/MAPK/NF-κB proinflammatory cascade response axis in the OHT mice. Our findings provide preliminary evidence for the RGC protective and microglia-associated neuroinflammatory reduction effects of ADSC-EVs by inhibiting the TLR4/MAPK/NF-κB proinflammatory cascade response in OHT mice, indicating the therapeutic potential ADSC-EVs or adjunctive therapy for glaucoma.

Molecular pathways in experimental glaucoma models

Glaucoma is a complex and progressive disease that primarily affects the optic nerve axons, leading to irreversible vision loss. Although the exact molecular mechanisms underlying glaucoma pathogenesis are not fully understood, it is believed that except increased intraocular pressure, a combination of genetic and environmental factors play a role in the development of the disease. Animal models have been widely used in the study of glaucoma, allowing researchers to better understand the underlying mechanisms of the disease and test potential treatments. Several molecular pathways have been implicated in the pathogenesis of glaucoma, including oxidative stress, inflammation, and excitotoxic-induced neurodegeneration. This review summarizes the most important knowledge about molecular mechanisms involved in the glaucoma development. Although much research has been done to better understand the molecular mechanisms underlying this disease, there is still much to be learned to develop effective treatments and prevent vision loss in those affected by glaucoma.

Suprachoroidal spheroidal mesenchymal stem cell implantation in retinitis pigmentosa: clinical results of 6 months follow-up

PURPOSE

This prospective clinical case series aimed to evaluate the effect of suprachoroidal implantation of mesenchymal stem cells (MSCs) in the form of spheroids as a stem cell therapy for retinitis pigmentosa (RP) patients with relatively good visual acuity.

METHODS

Fifteen eyes of 15 patients with RP who received suprachoroidal implantation of MSCs in the form of spheroids were included. Best-corrected visual acuity (BCVA), 10-2 and 30-2 visual field examination and multifocal electroretinography (mfERG) recordings were recorded at baseline, postoperative 1st, 3rd and 6th months during follow-up.

RESULTS

Baseline median BCVA of RP patients was 1.30 (1.00-2.00) logMAR. BCVA has improved to 1.00 (0.50-1.30), 0.80 (0.40-1.30) and 0.80 (0.40-1.30) at the postoperative 1st, 3rd and 6th months, respectively. The improvements from baseline to the 3rd and 6th months were statistically significant (p = 0.03 and p < 0.001, respectively). In the 30-2 VF test, median MD was significantly improved at the 6th month compared to baseline (p = 0.030). In the 10-2 VF test, the median MD value was significantly different at the 6th month compared to the baseline (p = 0.043). The PSD value of the 10-2 VF test was significantly different at the 6th month compared to the 3rd month (p = 0.043). The amplitudes of P1 waves in < 2°, 5°-10° and 10°-15° rings improved significantly at the postoperative 6th month (p = 0.014, p = 0.018 and p = 0.017, respectively). There was also a statistically significant improvement in implicit times of P1 waves in 10°-15° ring at the postoperative 6th month (p = 0.004).

CONCLUSION

Suprachoroidal implantation of MSCs in the form of spheroids as a stem cell therapy for RP patients with relatively good visual acuity has an improving effect on BCVA, VF and mfERG recordings during the 6-month follow-up period. Spheroidal MSCs with enhanced effects may be more successful in preventing apoptosis and improving retinal tissue healing in RP patients.

Erythropoietin in Glaucoma: From Mechanism to Therapy

Glaucoma can cause irreversible vision loss and is the second leading cause of blindness worldwide. The disease mechanism is complex and various factors have been implicated in its pathogenesis, including ischemia, excessive oxidative stress, neurotropic factor deprivation, and neuron excitotoxicity. Erythropoietin (EPO) is a hormone that induces erythropoiesis in response to hypoxia. However, studies have shown that EPO also has neuroprotective effects and may be useful for rescuing apoptotic retinal ganglion cells in glaucoma. This article explores the relationship between EPO and glaucoma and summarizes preclinical experiments that have used EPO to treat glaucoma, with an aim to provide a different perspective from the current view that glaucoma is incurable.

Cell-Based Neuroprotection of Retinal Ganglion Cells in Animal Models of Optic Neuropathies

Retinal ganglion cells (RGCs) comprise a heterogenous group of projection neurons that transmit visual information from the retina to the brain. Progressive degeneration of these cells, as it occurs in inflammatory, ischemic, traumatic or glaucomatous optic neuropathies, results in visual deterioration and is among the leading causes of irreversible blindness. Treatment options for these diseases are limited. Neuroprotective approaches aim to slow down and eventually halt the loss of ganglion cells in these disorders. In this review, we have summarized preclinical studies that have evaluated the efficacy of cell-based neuroprotective treatment strategies to rescue retinal ganglion cells from cell death. Intraocular transplantations of diverse genetically nonmodified cell types or cells engineered to overexpress neurotrophic factors have been demonstrated to result in significant attenuation of ganglion cell loss in animal models of different optic neuropathies. Cell-based combinatorial neuroprotective approaches represent a potential strategy to further increase the survival rates of retinal ganglion cells. However, data about the long-term impact of the different cell-based treatment strategies on retinal ganglion cell survival and detailed analyses of potential adverse effects of a sustained intraocular delivery of neurotrophic factors on retina structure and function are limited, making it difficult to assess their therapeutic potential.

Management of toxic optic neuropathy via a combination of Wharton's jelly-derived mesenchymal stem cells with electromagnetic stimulation

PURPOSE

To investigate the effect of the combination of Wharton's jelly derived mesenchymal stem cells (WJ-MSC) and high frequency repetitive electromagnetic stimulation (rEMS) in the therapy of toxic optic neuropathies with severe symptoms after the available current therapy modalities which were unsucessful.

MATERIAL AND METHODS

This prospective, open-label clinical phase-3 study was conducted at Ankara University Faculty of Medicine, Department of Ophthalmology between April 2019 and April 2021. Thirty-six eyes of 18 patients with toxic optic neuropathy (TON) were included in the study. Within 1-3 months after the emergency interventions, patients with various degrees of sequela visual disturbances were studied in this clinical trial. The cases were divided into three groups according to similar demographic characteristics. Group 1: Consists of 12 eyes of 12 patients treated with the WJ-MSC and rEMS combination in one eye. Group 2: Consists of 12 eyes of 12 patients treated with only rEMS in one eye. Group 3: Consists of 12 eyes of six patients treated with only WJ-MSC in both eyes. The course was evaluated by comparing the quantitive functional and structural assessment parameters measured before and at the fourth month of applications in each group.

RESULTS

The mean best corrected visual acuity (BCVA) delta change percentages of the groups can be ranked as: Group 1 (47%) > Group 3 (32%) > Group 2 (21%). The mean fundus perimetry deviation index (FPDI) delta change percentages of the groups can be ranked as: Group 1 (95%) > Group 2 (33%) > Group 3 (27%). The mean ganglion cell complex (GCC) thickness delta change (decrease in thickness) percentages can be ranked as: Group 1 (- 21%) > Group 3 (- 15%) > Group 2 (- 13%). The visual evoked potential (VEP) P100 latency delta change percentages of the groups can be ranked as: Group 1 (- 18%) > Group 3 (- 10%) > Group 2 (- 8%). The P100 amplitude delta change percentages of the groups can be ranked as: Group 1 (105%) > Group 3 (83%) > Group 2 (24%).

CONCLUSION

Toxic optic neuropathies are emergent pathologies that can result in acute and permanent blindness. After poisoning with toxic substances, progressive apoptosis continues in optic nerve axons and ganglion cells. After the proper first systemic intervention in intensive care clinic, the WJ-MSC and rEMS combination seems very effective in the short-term period in cases with TON. To prevent permanent blindness, a combination of WJ-MSC and rEMS application as soon as possible may increase the chance of success in currently untreatable cases. Trial Registration ClinicalTrials.gov ID: NCT04877067.

Umbilical cord mesenchymal stem/stromal cells potential to treat organ disorders; an emerging strategy

Currently, mesenchymal stem/stromal cells (MSCs) have attracted growing attention in the context of cell-based therapy in regenerative medicine. Following the first successful procurement of human MSCs from bone marrow (BM), these cells isolation has been conducted from various origins, in particular, the umbilical cord (UC). Umbilical cord-derived mesenchymal stem/stromal cells (UC-MSCs) can be acquired by a non-invasive plan and simply cultured, and thereby signifies their superiority over MSCs derived from other sources for medical purposes. Due to their unique attributes, including self-renewal, multipotency, and accessibility concomitant with their immunosuppressive competence and lower ethical concerns, UC-MSCs therapy is described as encouraging therapeutic options in cell-based therapies. Regardless of their unique aptitude to adjust inflammatory response during tissue recovery and delivering solid milieu for tissue restoration, UC-MSCs can be differentiated into a diverse spectrum of adult cells (e.g., osteoblast, chondrocyte, type II alveolar, hepatocyte, and cardiomyocyte). Interestingly, they demonstrate a prolonged survival and longer telomeres compared with MSCs derived from other sources, suggesting that UC-MSCs are desired source to use in regenerative medicine. In the present review, we deliver a brief review of UC-MSCs isolation, expansion concomitantly with immunosuppressive activities, and try to collect and discuss recent pre-clinical and clinical researches based on the use of UC-MSCs in regenerative medicine, focusing on with special focus on in vivo researches.

A Review on Mesenchymal Stem Cells for Treatment of Retinal Diseases

Mesenchymal Stem Cells (MSCs) have been studied extensively for the treatment of several retinal diseases. The therapeutic potential of MSCs lies in its ability to differentiate into multiple lineages and secretome enriched with immunomodulatory, anti-angiogenic and neurotrophic factors. Several studies have reported the role of MSCs in repair and regeneration of the damaged retina where the secreted factors from MSCs prevent retinal degeneration, improve retinal morphology and function. MSCs also donate mitochondria to rescue the function of retinal cells and exosomes secreted by MSCs were found to have anti-apoptotic and anti-inflammatory effects. Based on several promising results obtained from the preclinical studies, several clinical trials were initiated to explore the potential advantages of MSCs for the treatment of retinal diseases. This review summarizes the various properties of MSCs that help to repair and restore the damaged retinal cells and its potential for the treatment of retinal degenerative diseases.

Cell-based therapy for ocular disorders: A promising frontier

As the ocular disorders causing long-term blindness or optical abnormalities of the ocular tissue affect the quality of life of patients to a large extent, awareness of their corresponding pathogenesis and the earlier detection and treatment need more consideration. Though current therapeutics result in desirable outcomes, they do not offer an inclusive solution for development of visual impairment to blindness. Accordingly, stem cells, because of their particular competencies, have gained extensive attention for application in regenerative medicine of ocular diseases. In the last decades, a wide spectrum of stem cells surrounding mesenchymal stem/stromal cells (MSC), neural stem cells (NSCs), and embryonic/induced pluripotent stem cells (ESCs/iPSCs) accompanied by Müller glia, ciliary epithelia-derived stem cells, and retinal pigment epithelial (RPE) stem cells have been widely investigated to report their safety and efficacy in preclinical models and also human subjects. In this regard, in the first interventions, RPE cell suspensions were successfully utilized to ameliorate visual defects of the patients suffering from age-related macular degeneration (AMD) after subretinal transplantation. Herein, we will explain the pathogenesis of ocular diseases and highlight the novel discoveries and recent findings in the context of stem cell-based therapies in these disorders, focusing on the in vivo reports published during the last decade.

Human Umbilical Cord Mesenchymal Stem Cells-Secreted TSG-6 Is Anti-Inflammatory and Promote Tissue Repair After Spinal Cord Injury

Spinal cord injury (SCI) causes patients paralysis and hard to recover. The therapeutic effects of current clinical drugs are accompanied by side effects. In recent years, stem cell therapy has attracted the attention of researchers. Human umbilical cord mesenchymal stem cells (hucMSCs) have been widely used in various diseases due to their excellent paracrine function. TNF-stimulated gene 6 (TSG-6), a secretion factor of stem cells, may play an important role in hucMSCs in the treatment of SCI. So we conducted an experiment to explore its effect. We first observed that the expression of TSG-6 increased in SCI rats after injected with hucMSCs. Then, we used siRNA to knowdown the expression of TSG-6. We treated SCI rats with TSG-6-knockdown hucMSCs. Without TSG-6 expression, hucMSCs treatment made the tissue recovery worse and the number of Nissl bodies less. Meanwhile, neutrophils infiltrated more in the damaged parts. Our research also proved that TSG-6 may help demyelination recovering and alleviate astrocytes gathering in the injury sites. Our study revealed that hucMSCs secreted TSG-6 may decrease the degeneration of myelin sheath, reduce inflammation, decrease neuron loss and promote tissue repair. These results provided a new therapeutic factor for the treatment of SCI.

Transplanted Erythropoietin-Expressing Mesenchymal Stem Cells Promote Pro-survival Gene Expression and Protect Photoreceptors From Sodium Iodate-Induced Cytotoxicity in a Retinal Degeneration Model

Mesenchymal stem cells (MSC) are highly regarded as a potential treatment for retinal degenerative disorders like retinitis pigmentosa and age-related macular degeneration. However, donor cell heterogeneity and inconsistent protocols for transplantation have led to varied outcomes in clinical trials. We previously showed that genetically-modifying MSCs to express erythropoietin (MSC^EPO) improved its regenerative capabilities in vitro. Hence, in this study, we sought to prove its potential in vivo by transplanting MSCs^EPO in a rat retinal degeneration model and analyzing its retinal transcriptome using RNA-Seq. Firstly, MSCs^EPO were cultured and expanded before being intravitreally transplanted into the sodium iodate-induced model. After the procedure, electroretinography (ERG) was performed bi-weekly for 30 days. Histological analyses were performed after the ERG assessment. The retina was then harvested for RNA extraction. After mRNA-enrichment and library preparation, paired-end RNA-Seq was performed. Salmon and DESeq2 were used to process the output files. The generated dataset was then analyzed using over-representation (ORA), functional enrichment (GSEA), and pathway topology analysis tools (SPIA) to identify enrichment of key pathways in the experimental groups. The results showed that the MSC^EPO-treated group had detectable ERG waves (P <0.05), which were indicative of successful phototransduction. The stem cells were also successfully detected by immunohistochemistry 30 days after intravitreal transplantation. An initial over-representation analysis revealed a snapshot of immune-related pathways in all the groups but was mainly overexpressed in the MSC group. A subsequent GSEA and SPIA analysis later revealed enrichment in a large number of biological processes including phototransduction, regeneration, and cell death (P_adj <0.05). Based on these pathways, a set of pro-survival gene expressions were extracted and tabulated. This study provided an in-depth transcriptomic analysis on the MSC^EPO-treated retinal degeneration model as well as a profile of pro-survival genes that can be used as candidates for further genetic enhancement studies on stem cells.

Mesenchymal Stem Cell-Based Therapy for Retinal Degenerative Diseases: Experimental Models and Clinical Trials

Retinal degenerative diseases, such as age-related macular degeneration, retinitis pigmentosa, diabetic retinopathy or glaucoma, represent the main causes of a decreased quality of vision or even blindness worldwide. However, despite considerable efforts, the treatment possibilities for these disorders remain very limited. A perspective is offered by cell therapy using mesenchymal stem cells (MSCs). These cells can be obtained from the bone marrow or adipose tissue of a particular patient, expanded in vitro and used as the autologous cells. MSCs possess potent immunoregulatory properties and can inhibit a harmful inflammatory reaction in the diseased retina. By the production of numerous growth and neurotrophic factors, they support the survival and growth of retinal cells. In addition, MSCs can protect retinal cells by antiapoptotic properties and could contribute to the regeneration of the diseased retina by their ability to differentiate into various cell types, including the cells of the retina. All of these properties indicate the potential of MSCs for the therapy of diseased retinas. This view is supported by the recent results of numerous experimental studies in different preclinical models. Here we provide an overview of the therapeutic properties of MSCs, and their use in experimental models of retinal diseases and in clinical trials.

The Benefits and Hazards of Intravitreal Mesenchymal Stem Cell (MSC) Based-Therapies in the Experimental Ischemic Optic Neuropathy

Mesenchymal stem cell (MSC) therapy has been investigated intensively for many years. However, there is a potential risk related to MSC applications in various cell niches. Methods: The safety of intravitreal MSC application and the efficacy of MSC-derived conditioned medium (MDCM) were evaluated in the normal eye and the diseased eye, respectively. For safety evaluation, the fundus morphology, visual function, retinal function, and histological changes of the retina were examined. For efficacy evaluation, the MDCM was intravitreally administrated in a rodent model of anterior ischemic optic neuropathy (rAION). The visual function, retinal ganglion cell (RGC) density, and neuroinflammation were evaluated at day 28 post-optic nerve (ON) infarct. Results: The fundus imaging showed that MSC transplantation induced retinal distortion and venous congestion. The visual function, retinal function, and RGC density were significantly decreased in MSC-treated eyes. MSC transplantation induced astrogliosis, microgliosis, and macrophage infiltration in the retina due to an increase in the HLA-DR-positive MSC proportion in vitreous. Treatment with the MDCM preserved the visual function and RGC density in rAION via inhibition of macrophage infiltration and RGC apoptosis. Conclusions: The vitreous induced the HLA-DR expression in the MSCs to cause retinal inflammation and retina injury. However, the MDCM provided the neuroprotective effects in rAION.

Exosomes from human umbilical cord Mesenchymal stem cells attenuates stress-induced hippocampal dysfunctions

Human Mesenchymal Stem Cells (MSCs) especially human umbilical cord MSCs is the novel regenerative cell resource for regenerative therapy. However, the biological underpinning of MSCs in neuroprotections requires deep understanding. Exosomes is an important biological factor due to its multiple types of contents with various biological function. In current study, we collected the exosome from umbilical cord mesenchymal stem cells (hUC-MSCs) and tested the neuroprotective effects to brain stress. Proteomic analysis indicates significant enriched protein components display the functions in metabolic regulation. We then injected the exosome (MSC-Ex) to adult mice by i.v injection. On physiological level, treatment of MSC-Ex increased the adiponectin level in peripheral central nervous system (CNS). Moreover, MSC-Ex significantly accelerated the differentiation of adult neural stem cells but did not benefit the related cognitive behavior. We then created acute brain disorder model with STZ intra-hippocampal injection. Compared with STZ group, treatment of MSC-Ex improved cognitive function. Moreover, MSC-Ex promotes hippocampal neurogenesis that was suppressed by STZ injection. In conclusion, hUC-MSCs derived exosome would exert the neural regenerative effects associating with its metabolism regulatory capacity.

Treatment of Optic Canal Decompression Combined with Umbilical Cord Mesenchymal Stem (Stromal) Cells for Indirect Traumatic Optic Neuropathy: A Phase 1 Clinical Trial

PURPOSE

This study was aimed to investigate the safety and feasibility of umbilical cord-derived mesenchymal stem cell (MSC) transplantation in patients with traumatic optic neuropathy (TON).

METHODS

This is a single-center, prospective, open-labeled phase 1 study that enrolled 20 patients with TON. Patients consecutively underwent either optic canal decompression combined with MSC local implantation treatment (group 1) or only optic canal decompression (group 2). Patients were evaluated on the first day, seventh day, first month, third month, and sixth month postoperatively. Adverse events, such as fever, urticarial lesions, nasal infection, and death, were recorded at each visit. The primary outcome was changes in best-corrected visual acuity. The secondary outcomes were changes in color vision, relative afferent pupillary defect, and flash visual evoked potential.

RESULTS

All 20 patients completed the 6-month follow-up. None of them had any systemic or ocular complications. The change in best-corrected visual acuity at follow-up was not significantly different between group 1 and group 2 (p > 0.05); however, group 1 showed better visual outcome than group 2. Both groups showed significant improvements in vision compared with the baseline (p < 0.05); however, there were no statistically significant differences between the groups (p > 0.05). In addition, no adverse events related to local transplantation were observed in the patients.

CONCLUSIONS

A single, local MSC transplantation in the optic nerve is safe for patients with TON.

Management of retinitis pigmentosa by Wharton's jelly-derived mesenchymal stem cells: prospective analysis of 1-year results

PURPOSE

The aim of the study was to investigate annual structural and functional results, and their correlation with inheritance pattern of retinitis pigmentosa (RP) patients who were treated with Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs).

MATERIAL AND METHODS

This prospective, sequential, open-label phase-3 clinical study was conducted at Ankara University Faculty of Medicine, Department of Ophthalmology, between April 2019 and May 2020. The study included 34 eyes from 32 retinitis pigmentosa patients of various genotypes who were enrolled in the stem cells clinical trial. The patients were followed for 12 months after the WJ-MSCs transplantation into subtenon space and evaluated with consecutive examinations. Genetic mutations were investigated using a retinitis pigmentosa panel sequencing method consisting of 90 genes. All patients underwent a complete routine ophthalmic examination with best corrected visual acuity, optical coherence tomography angiography, visual field, and full-field electroretinography. Quantitative data obtained from baseline (T0), 6th month (T1), and 12th month (T2) examinations were compared.

RESULTS

According to timepoints at T0, T1, and T2: The mean outer retinal thickness was 100.3 μm, 119.1 μm, and 118.0 μm, respectively (p = 0.01; T0 < T1, T2). The mean horizontal ellipsoid zone width were 2.65 mm, 2.70 mm, and 2.69 mm respectively (p = 0.01; T0 < T1, T2). The mean best corrected visual acuity (BCVA) were 70.5 letters, 80.6 letters, and 79.9 letters, respectively (p = 0.01; T0 < T1, T2). The mean fundus perimetry deviation index (FPDI) was 8.0%, 11.4%, and 11.6%, respectively (p = 0.01; T0 < T1, T2). The mean full-field flicker ERG parameters at T0, T1, and T2: amplitudes were 2.4 mV, 5.0 mV, and 4.6 mV, respectively (p = 0.01; T0 < T1, T2). Implicit time were 43.3 ms, 37.9 ms, and 38.6 ms, respectively (p = 0.01; T0 > T1, T2). According to inheritance pattern, BCVA, FPDI, ERG amplitude, and implicit time data improved significantly in autosomal dominant (AD) and in autosomal recessive (AR) RP at 1 year follow-up (pAD = 0.01, pAR = 0.01; pAD = pAR > pX-linked). No ocular or systemic adverse events related to the surgical methods and/or WJ-MSCs were observed during the 1 year follow-up period.

CONCLUSION

Subtenon transplantation of WJ-MSCs was found to be effective and safe in the treatment of RP during the first year, similar to the sixth month's results. In autosomal dominant and autosomal recessive inheritance of RP, regardless of the genetic mutations, subtenon administration of WJ-MSCs can be considered an effective and safe option without any adverse effect for slowing or stopping the disease progression.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04224207 . Registered 8 January 2020.

An Endostatin-lentivirus (ES-LV)-EPC gene therapy agent for suppression of neovascularization in oxygen-induced retinopathy rat model

BACKGROUND

Transplantation of gene transfected endothelial progenitor cells (EPCs) has provided novel methods for tumor neovascularization therapy but not for ocular disease therapy. This study aimed to investigate the efficacy of endostatin transfected EPCs in retinal neovascularization therapy.

RESULTS

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) showed the high expression of endostatin in endostatin-lentivirus-EPCs. The neovascularization leakage area and the number of preretinal neovascular cell nuclei were significantly decreased in the endostatin-lentivirus and endostatin-lentivirus-EPC groups, and the effects of these two treatments on inhibiting retinal neovascularization were almost the same. These two groups also showed the greater retinal distribution of endostatin. Intravitreal injections of endostatin-lentivirus-EPCs inhibited retinal neovascularization, vascular endothelial growth factor (VEGF) and CD31 expression, and increased endostatin expression in vivo. Endostatin-lentivirus-EPCs targeted and prevented pathologic retinal neovascularization.

CONCLUSIONS

Gene-combined EPCs represent a potential new therapeutic agent for the treatment of neovascular eye diseases.

Umbilical Cord Blood and Serum for the Treatment of Ocular Diseases: A Comprehensive Review

Several blood derivatives have been proposed for the treatment of various ocular diseases that affect either the anterior or the posterior segment of the eye. Blood sources may range from the patient’s own peripheral blood (autologous) to donor tissues, mainly allogeneic peripheral blood and umbilical cord blood (UCB). The utilization of the latter permits the collection of a large amount of serum all at once, and is characterized by therapeutic feasibility in patients with a poor general condition or anemia and blood dyscrasia. Products derived from UCB have two potential uses. First, serum in the form of eye drops can be applied topically onto the ocular surface to efficiently treat anterior segment disorders such as dry eye syndrome or corneal epithelial defects with different etiologies. The rationale for and efficacy of this application derive from the high concentrations of biologically active components and growth factors in UCB, which can nourish the ocular surface. Second, UCB is a source of stem cells, which are used in the field of regenerative medicine because they differentiate into various mature cells, including corneal and retinal cells. Therefore, UCB-derived stem cells have been proposed as a replacement therapy for the treatment of retinal and optic nerve diseases, given that current standard treatments often fail. The present review explores the clinical results that have been obtained using UCB-derived products in the field of ophthalmology, as well as the current limitations of those products in this field. Furthermore, given the promising development of UCB-based therapies, possible future directions in this area are discussed.

Management of retinitis pigmentosa by Wharton's jelly derived mesenchymal stem cells: preliminary clinical results

PURPOSE

The aim of this study is to determine if umbilical cord Wharton's jelly derived mesenchymal stem cells implanted in sub-tenon space have beneficial effects on visual functions in retinitis pigmentosa patients by reactivating the degenerated photoreceptors in dormant phase.

MATERIAL AND METHODS

This prospective, open-label, phase-3 clinical trial was conducted between April of 2019 and October of 2019 at Ankara University Faculty of Medicine, Department of Ophthalmology. 32 RP patients (34 eyes) were included in the study. The patients were followed for 6 months after the Wharton's jelly derived mesenchymal stem cell administration, and evaluated with consecutive examinations. All patients underwent a complete routine ophthalmic examination, and best corrected visual acuity, optical coherens tomography angiography, visual field, multifocal and full-field electroretinography were performed. The quantitative results were obtained from a comparison of the pre-injection and final examination (6th month) values.

RESULTS

The mean best corrected visual acuity was 70.5 letters prior to Wharton's jelly derived mesenchymal stem cell application and 80.6 letters at the 6th month (p = 0.01). The mean visual field median deviation value was 27.3 dB before the treatment and 24.7 dB at the 6th month (p = 0.01). The mean outer retinal thickness was 100.3 μm before the treatment and 119.1 μm at 6th month (p = 0.01). In the multifocal electroretinography results, P1 amplitudes improved in ring1 from 24.8 to 39.8 nv/deg2 (p = 0.01), in ring2 from 6.8 to 13.6 nv/deg2 (p = 0.01), and in ring3 from 3.1 to 5.7 nv/deg2 (p = 0.02). P1 implicit times improved in ring1 from 44.2 to 32.4 ms (p = 0.01), in ring2 from 45.2 to 33.2 ms (p = 0.02), and in ring3 from 41.9 to 32.4 ms (p = 0.01). The mean amplitude improved in 16 Tds from 2.4 to 5.0 nv/deg2 (p = 0.01) and in 32 Tds from 2.4 to 4.8 nv/deg2 (p = 0.01) in the full-field flicker electroretinography results. Full field flicker electroretinography mean implicit time also improved in 16 Tds from 43.3 to 37.9 ms (p = 0.01). No ocular or systemic adverse events related to the two types of surgical methods and/or Wharton's jelly derived mesenchymal stem cells itself were observed during the follow-up period.

CONCLUSION

RP is a genetic disorder that can result in blindness with outer retinal degeneration. Regardless of the type of genetic mutation, sub-tenon Wharton's jelly derived mesenchymal stem cell administration appears to be an effective and safe option. There are no serious adverse events or ophthalmic / systemic side effects for 6 months follow-up. Although the long-term adverse effects are still unknown, as an extraocular approach, subtenon implantation of the stem cells seems to be a reasonable way to avoid the devastating side effects of intravitreal/submacular injection. Further studies that include long-term follow-up are needed to determine the duration of efficacy and the frequency of application.

TRIAL REGISTRATION

SHGM56733164. Redistered 28 January 2019 https://shgm.saglik.gov.tr/organ-ve-doku-nakli-koordinatorlugu/56733164/203 E.507.

Cytokine interplay among the diseased retina, inflammatory cells and mesenchymal stem cells - a clue to stem cell-based therapy

Retinal degenerative disorders, such as diabetic retinopathy, retinitis pigmentosa, age-related macular degeneration or glaucoma, represent the most common causes of loss of vision and blindness. In spite of intensive research, treatment options to prevent, stop or cure these diseases are limited. Newer therapeutic approaches are offered by stem cell-based therapy. To date, various types of stem cells have been evaluated in a range of models. Among them, mesenchymal stem/stromal cells (MSCs) derived from bone marrow or adipose tissue and used as autologous cells have been proposed to have the potential to attenuate the negative manifestations of retinal diseases. MSCs delivered to the vicinity of the diseased retina can exert local anti-inflammatory and repair-promoting/regenerative effects on retinal cells. However, MSCs also produce numerous factors that could have negative impacts on retinal regeneration. The secretory activity of MSCs is strongly influenced by the cytokine environment. Therefore, the interactions among the molecules produced by the diseased retina, cytokines secreted by inflammatory cells and factors produced by MSCs will decide the development and propagation of retinal diseases. Here we discuss the interactions among cytokines and other factors in the environment of the diseased retina treated by MSCs, and we present results supporting immunoregulatory and trophic roles of molecules secreted in the vicinity of the retina during MSC-based therapy.

Human Umbilical Cord Mesenchymal Stem Cells Attenuate Ocular Hypertension-Induced Retinal Neuroinflammation via Toll-Like Receptor 4 Pathway

Glaucoma is characterized by progressive, irreversible damage to the retinal ganglion cells (RGCs) and their axons. Our previous study has shown that the intravitreal transplantation of human umbilical cord mesenchymal stem cells (hUC-MSCs) reveals a neuroprotective role in microsphere injection-induced ocular hypertension (OHT) rat models. The protection is related to the modulation of glial cells, but the mechanisms are still unknown. The purpose of the present study is to clarify the potential neuroinflammatory mechanisms involved in the neuroprotective role of hUC-MSCs. OHT models were established with SD rats through intracameral injection of polystyrene microbeads. The animals were randomly divided into three groups: the normal group, the OHT+phosphate-buffered saline (PBS) group, and the OHT+hUC-MSC group. Retinal morphology was evaluated by measuring the inner retinal thickness via optical coherence tomography (OCT). Retinal cell apoptosis was examined by TUNEL staining and Bax expression 14 days following hUC-MSC transplantation. The expression levels of glial fibrillary acidic protein (GFAP), ionized calcium binding adapter molecule 1 (iba-1), and toll-like receptor 4 (TLR4) were assessed via immunohistochemistry, real-time quantitative PCR, and Western blot. RNA and proteins were extracted 14 days following transplantation, and the expression levels of the TLR4 signaling pathways and proinflammatory cytokines—myeloid differentiation factor 88 (MyD88), IL-1β, IL-6, and TNF-α—were determined. OCT showed that the intravitreal transplantation of hUC-MSCs significantly increased the inner thickness of the retina. A TUNEL assay and the expression of Bax suggested that the apoptosis of retinal cells was decreased by hUC-MSCs 14 days following transplantation. Intravitreal hUC-MSC transplantation resulted in a decreased expression of GFAP, iba-1, TLR4, MyD88, IL-1β, IL-6, and TNF-α 14 days following transplantation. In addition, via in vitro experiments, we found that the increased expression of the TLR4 signaling pathway induced by lipopolysaccharide (LPS) was markedly decreased after hUC-MSCs were cocultured with rMC-1 and BV2 cells. These findings indicate that hUC-MSC transplantation attenuates OHT-induced retinal neuroinflammation via the TLR4 pathway.

Dental pulp stem cells therapy overcome photoreceptor cell death and protects the retina in a rat model of sodium iodate-induced retinal degeneration

Blindness and vision loss contribute to irreversible retinal degeneration, and cellular therapy for retinal cell replacement has the potential to treat individuals who have lost light sensitive photoreceptors in the retina. Retinal cells are well characterized in function, and are a subject of interest in cellular replacement therapy of photoreceptors and the retinal pigment epithelium. However, retinal cell transplantation is limited by various factors, including the choice of potential stem cell source that can show variability in plasticity as well as host tissue integration. Dental pulp is one such source that contains an abundance of stem cells. In this study we used dental pulp-derived mesenchymal stem cells (DPSCs) to mitigate sodium iodate (NaIO₃) insult in a rat model of retinal degeneration. Sprague-Dawley rats were first given an intravitreal injection of 3 × 10⁵ DPSCs as well as a single systemic administration of NaIO₃ (40 mg/kg). Electroretinography (ERG) was performed for the next two months and was followed-up by histological analysis. The ERG recordings showed protection of DPSC-treated retinas within 4 weeks, which was statistically significant (* P ≤ .05) compared to the control. Retinal thickness of the control was also found to be thinner (*** P ≤ .001). The DPSCs were found integrated in the photoreceptor layer through immunohistochemical staining. Our findings showed that DPSCs have the potential to moderate retinal degeneration. In conclusion, DPSCs are a potential source of stem cells in the field of eye stem cell therapy due to its protective effects against retinal degeneration.

Mesenchymal stromal cell therapy for damaged retinal ganglion cells, is gold all that glitters?

Mesenchymal stromal cells are an excellent source of stem cells because they are isolated from adult tissues or perinatal derivatives, avoiding the ethical concerns that encumber embryonic stem cells. In preclinical models, it has been shown that mesenchymal stromal cells have neuroprotective and immunomodulatory properties, both of which are ideal for central nervous system treatment and repair. Here we will review the current literature on mesenchymal stromal cells, focusing on bone marrow mesenchymal stromal cells, adipose-derived mesenchymal stromal cells and mesenchymal stromal cells from the umbilical cord stroma, i.e., Wharton's jelly mesenchymal stromal cells. Finally, we will discuss the use of these cells to alleviate retinal ganglion cell degeneration following axonal trauma.

Human Wharton's jelly mesenchymal stem cells protect axotomized rat retinal ganglion cells via secretion of anti-inflammatory and neurotrophic factors

Mesenchymal stem cell (MSC) transplantation is emerging as an ideal tool to restore the wounded central nervous system (CNS). MSCs isolated from extra-embryonic tissues have some advantages compared to MSCs derived from adult ones, such as an improved proliferative capacity, life span, differentiation potential and immunomodulatory properties. In addition, they are more immunoprivileged, reducing the probability of being rejected by the recipient. Umbilical cords (UCs) are a good source of MSCs because they are abundant, safe, non-invasively harvested after birth and, importantly, they are not encumbered with ethical problems. Here we show that the intravitreal transplant of Wharton´s jelly mesenchymal stem cells isolated from three different human UCs (hWJMSCs) delays axotomy-induced retinal ganglion cell (RGC) loss. In vivo, hWJMSCs secrete anti-inflammatory molecules and trophic factors, the latter alone may account for the elicited neuroprotection. Interestingly, this expression profile differs between naive and injured retinas, suggesting that the environment in which the hWJMSCs are modulates their secretome. Finally, even though the transplant itself is not toxic for RGCs, it is not innocuous as it triggers a transient but massive infiltration of Iba1⁺cells from the choroid to the retina that alters the retinal structure.