A New Technique for Harvesting Limbal Stem Cell Tissue for Transplantation Using an Automated Microkeratome and a Novel Globe-Fixation System.

PURPOSE: To introduce an unprecedented technique, instrumentation, and setup for the superficial limbus harvest from the human cadaver donor whole globe. METHODS: We studied several superficial limbus harvest alternatives, developed a preferred approach with our available instruments, and optimized it on a handful of (seropositive) cadaver donors of whole globes. RESULTS/TECHNIQUE: The globe was pressurized to about normal intraocular pressure by viscoelastic injection through the optic nerve stump. The globe was then mounted on a dynamic globe fixator that maintained a negative pressure in its stabilizing socket. Exertion of the negative pressure effectively elevated globe intraocular pressure (to over 40 mm Hg) and made the corneoscleral wall tight. The socket was then held tilted to the left side for about 35 to 40 degrees to put the limbal zone horizontally and mildly "chin-up." Next, the microkeratome was put on the uppermost and exposed limbus of the globe and activated, and the socket was rotated clockwise under the microkeratome head and its oscillating blade, allowing an effective 360-degree revolution of the microkeratome head around the limbal belt (for a right-handed operator and a counterclockwise cut). CONCLUSIONS: We consistently succeeded in peeling intact 360-degree strips of the smooth superficial limbus by using blades with varying depths. Our method can be further equipped and optimized and be used by the eye banks and the surgeons for keratolimbal grafting as a more efficient limbal stem cell tissue harvest technique.

Triamcinolone-loaded self nano-emulsifying drug delivery systems for ocular use: An alternative to invasive ocular surgeries and injections.

Inflammation of the posterior segment of the eye is a severe condition and hard to cure as delivery of drugs to the inflammation site is inefficient. Currently, the primary treatment approach is ocular surgery or invasive ocular injections. Herein, we designed and developed a topically self nano-emulsifying drug delivery system (SNEDDs) to deliver triamcinolone acetonide (TCA) to the posterior segment of the eye. A screening based on TCA solubility was conducted on each excipient followed by preparation of various formulations using different ratios of the selected excipients. Vesicles of optimized SNEDDs had less than 100 nm size and spherical morphology. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay showed self-emulsified vesicles have relatively high safety on retinal pigment epithelium (RPE) cell line. Furthermore, efficient cellular uptake of coumarin 6-loaded SNEDDs in RPE using confocal laser scanning microscopy (CLSM) was confirmed. In addition, an in-vivo study using hematoxylin and eosin (H&E) staining revealed that 14 days of topical treatment of albino rabbit eyes with TCA-loaded SNEDDs was safe and no sign of tissue destruction and inflammation was detected in different parts of the eye sections including cornea, sclera, retina, and optic nerve. Also, the CLSM images from topically treated eyes with coumarin 6 (a hydrophobic, fluorescent drug model) loaded SNEDDs, showed that the optimized SNEDDs could properly penetrate toward the posterior segments of the eye especially the retina, posterior parts of the choroid, and sclera. Considering the outstanding results obtained by ocular tissue penetration and low toxicity, prepared SNEDDs, have the potential to be used as a topical administration for treating posterior segment disorders of the eye through an utterly non-invasive route and TCA-loaded SNEDDs could be an alternative for TCA intravitreal and intra conjunctival injections.

Unusual orbital mucormycosis due to pecking injury: clinical characteristics and outcomes of four immunocompetent pediatric patients.

Mucormycosis is a serious fungal infection caused by fungi in the order of Mucorales. Orbital mucormycosis occurs more frequently in rhino-orbital, sino-orbital, and rhino-orbito-cerebral forms of the disease, while isolated orbital mucormycosis is much less common. Herein, we present four cases of immunocompetent children who developed primary cutaneous mucormycosis, which subsequently invaded and progressed to orbital mucormycosis following direct traumatic injury caused by pecking from Acridotheres tristis (Common Myna). Given the low prevalence of orbital mucormycosis in healthy children, an unknown source of infection and delayed diagnosis followed by late therapeutic interventions could result in life-threatening conditions and serious sequelae.

Machine learning for classification of cutaneous sebaceous neoplasms: implementing decision tree model using cytological and architectural features.

BACKGROUND: This observational study aims to describe and compare histopathological, architectural, and nuclear characteristics of sebaceous lesions and utilized these characteristics to develop a predictive classification approach using machine learning algorithms. METHODS: This cross-sectional study was conducted on Iranian patients with sebaceous tumors from two hospitals between March 2015 and March 2019. Pathology slides were reviewed by two pathologists and the architectural and cytological attributes were recorded. Multiple decision tree models were trained using 5-fold cross validation to determine the most important predictor variables and to develop a simple prediction model. RESULTS: This study assessed the characteristics of 123 sebaceous tumors. Histopathological findings, including pagetoid appearance, neurovascular invasion, atypical mitosis, extensive necrotic area, poor cell differentiation, and non-lobular tumor growth pattern, as well as nuclear features, including highly irregular nuclear contour, and large nuclear size were exclusively observed in carcinomatous tumors. Among non-carcinomatous lesions, some sebaceoma and sebaceous adenoma cases had features like high mitotic activity, which can be misleading and complicate diagnosis. Based on multiple decision tree models, the five most critical variables for lesion categorization were identified as: basaloid cell count, peripheral basaloid cell layers, tumor margin, nuclear size, and chromatin. CONCLUSIONS: This study implemented a machine learning modeling approach to help optimally categorize sebaceous lesions based on architectural and nuclear features. However, studies of larger sample sizes are needed to ensure the accuracy of our suggested predictive model.

The Antitumor Effect of Topotecan Loaded Thiolated Chitosan-Dextran Nanoparticles for Intravitreal Chemotherapy: A Xenograft Retinoblastoma Model.

Purpose: This research intended to fabricate the thiolated chitosan-dextran nanoparticles (NPs) containing topotecan (TPH-CMD-TCS-NPs) to assess the ability of NPs in improving the efficacy of intravitreal chemotherapy of retinoblastoma in a rabbit xenograft model. Methods: The coacervation process was used to produce the NPs. The cellular uptake of Cyanine-3 (CY3)-labeled NPs were investigated in human retinoblastoma Y79 cells using confocal microscopy. Also, the prepared TPH-CMD-TCS-NPs were tested in vitro by the tetrazolium dyes II (XTT) and flow cytometry in order to assess their cytotoxicity. In addition, a rabbit xenograft model of retinoblastoma was developed to test the antitumor effectiveness of TPH-CMD-TCS-NPs through intravitreal administration. Results: NPs had a mean diameter, polydispersity index, and zeta potential of 30 ± 4 nm, 0.24 ± 0.03 and +10 ± 3 mV, respectively. NPs (IC50s 40.40 compared to 126.20 nM, P = 0.022) were more effective than free topotecan as a dose-based feature. The tumor reaction to intravitreal chemotherapy with NPs was measured by evaluating the percentage of necrosis in the tumor tissue (91 ± 2%) and vitreous seeds (89 ± 9%) through hematoxylin and eosin (H&E) staining. In comparison with the control group, the TPH-CMD-TCs-NPs treated group showed a significant decrease in tumor volume seven days after the intravitreal injection (P = 0.039). No significant changes were found in the ERG parameters after the intravitreal injection of TPH-CMD-TCs-NPs or TPH (P > 0.05). Conclusion: This investigation revealed definitive antitumor efficacy of TPH-CMD-TCS-NPs by intravitreal administration in the rabbit xenograft retinoblastoma model.

Microbiological Profile of Ocular Infection: A Large Retrospective Study.

Background: We aimed to elucidate the pathogenic bacterial and fungal profiles of specimens obtained from suspected ocular infections at Farabi Eye Tertiary Referral Hospital, Tehran, Iran. Methods: In this cross-sectional study, we collected data from ocular specimens taken during the seven-year period of 2011 to 2018, and the results were then retrospectively analyzed. Samples had been obtained from patients who were investigated for ocular infections. Results: Overall, 16,656 ocular samples were evaluated. The mean patient age was 48.31 ± 26.62 years. Most patients were men (60.33%), and men in the 7th decade of life were the largest represented group. The seasonal distributions of specimen collection sites followed the overall distribution of collection sites by year. Specimens obtained from the cornea were the most common (49.24%), also representing the largest number of specimens in all seasons. The most commonly isolated fungal microorganisms were Fusarium spp., followed by Aspergillus spp. and Candida albicans. Of the 6,556 specimens with positive bacterial cultures, 59% produced gram-positive bacteria, while the remainder produced gram-negative pathogens. The most commonly isolated bacteria were Pseudomonas aeruginosa (17.77%), Staphylococcus epidermidis (13.80%), Streptococcus pneumoniae (13.27%), S. viridans (12.23%), and S. aureus (11.18%). Conclusion: Most submitted specimens were obtained from the cornea. The most commonly isolated fungal microorganisms were Fusarium spp., followed by Aspergillus spp. and C. albicans. The most commonly isolated bacteria were P. aeruginosa, followed by S. epidermidis and S. pneumoniae.

Histopathology Study of Patients with Delayed Mustard Gas Keratopathy 30 Years After Exposure.

Background & Objective: Delayed mustard gas keratopathy (DMGK) is the main chronic outcome in eye-chemical injured patients. The aim of this study was the histopathological evaluation of mustard-exposed cornea after more than 30 years. Methods: Fourteen corneas after Lamellar keratoplasty were evaluated in this study. Corneal tissues were prepared by histologic methods and stained by H&E. Results: The main histopathological findings in these cases were the presence of severe stromal edema and corneal scar. In the sections with visible superficial epithelium, subepithelial bullae formation was observed. Focal or diffuse disruption of Bowman's membrane and replacement with fibrosis were also seen. There was no evidence of stromal vascularization and inflammation in all specimens. Conclusion: After more than 30 years, an extensive corneal scar is seen in sulfur mustard exposed patients. Scar tissue without vascularization and fibroblastic proliferation is the main finding in the sulfur mustard exposed cornea. This pathology result is different from other scars. No evidence of inflammation or immune cell infiltration should be considered in managing DMGK.

Intracameral Injection of Methotrexate for Treatment of Epithelial Ingrowth.

Purpose: To report a case of intracameral injection of methotrexate (MTX) to treat the epithelial ingrowth that occurred following glaucoma surgery. Methods: A case report of a 40-year-old male with epithelial ingrowth after implantation of Ahmed glaucoma valve. Results: The patient was treated with 11 doses of weekly intracameral MTX (400 mg/0.1 ml). Clinical evidence of recurrence was not observed after 11 months of follow-up. Discussion: Intracameral MTX can be used as an alternative for the treatment of epithelial ingrowth.

Orbital Dirofilariasis Masquerading As Orbital Rhabdomyosarcoma.

Purpose: To report a 12-year-old patient with a rapid growing orbital mass and imaging findings suggestive of rhabdomyosarcoma that was found to be dirofilariasis after mass resection. Case Report: We describe a 12-year-old patient with a rapid growing orbital mass involving medial part of orbit and medial rectus muscle and imaging findings suggestive of rhabdomyosarcoma. Histopathologic examination showed the mass to be composed of granulomatous inflammation and the thread-like object to be Dirofilaria repens. The patient was well post-operation without morbidity. In this paper, we describe distinct clinical features and imaging findings of this interesting case. Conclusion: Deep orbital lesions due to dirofilariasis, as in our case, is extremely rare. It is important to add dirofilariasis to the differential diagnosis of orbital mass lesions. Attention to the imaging clues, as provided in this report, can be helpful.

Ocular safety of repeated intravitreal injections of Carboplatin and Digoxin: A preclinical study on the healthy rabbits.

To evaluate the ocular safety of intravitreal carboplatin and digoxin injections as a new intravitreal chemotherapy option for retinoblastoma tumor vitreous seeds. Eighteen rabbits were divided randomly into three groups to receive intravitreal injection of Digoxin (6 rabbits), Carboplatin (7 rabbits), or Saline (5 rabbits). In every group, one eye randomly treated with 10 µg Digoxin in 0.1 cc or 1 µg Carboplatin or Saline, and the contralateral eye was considered as the control. All groups underwent three consecutive injections of the drugs with 1-week intervals. Baseline electroretinography (ERG) was recorded from both eyes of all the animals prior to injection and was repeated 1st day, 1st week, and 1st month after the last injection. All rabbits were sacrificed 1 month after the last injection, and histological studies were done. Mean a and b wave amplitudes decreased significantly at 1st day, 1st week, and 1st month after the last intravitreal injection of 10 µg Digoxin in comparison with other groups (p-value: .02). Contradictory, 1 µg Carboplatin injected eyes had minimal ERG changes. There were some nonspecific ERG changes with unclear clinical significance in non-injected contralateral control eyes of Digoxin and Carboplatin groups in comparison with the control eyes of the Saline group. Histological studies revealed considerable neural retinal atrophy in injected eyes of the Digoxin group. Intravitreal 10 µg Digoxin might have more local ocular toxicity in comparison with intravitreal Carboplatin in albino rabbit eyes. Future studies should assess the induced toxicity of intravitreal injection of these drugs on the non-injected contralateral eye.

Histological and ultrasonographic alterations in skin and soft tissue in upper eyelid excised blepharoplasty due to ipsilateral eyebrow tattooing: (preliminary findings).

BACKGROUND: Eyebrow tattooing (ET) is a relatively common cosmetic procedure for middle-aged women which can hide age-related ptosis. AIMS: We aimed to evaluate the periocular soft tissue changes following ET and its effects on upper eyelid blepharoplasty (UEBL). PATIENTS/METHODS: In this non-randomized prospective case-controlled study, 28 subjects recruited, 14 with ET for at least 5 years and 14 without ET. Eyebrows ultrasonography was performed to measure the periocular soft tissue thickness including skin and subcutaneous tissue on the medial and lateral side of the eyebrow. Then, UEBL was performed with extended eyelid skin incisions. So, the excised tissues being evaluated histopathologically. RESULTS: The mean age of patients was 50.6 ± 0.6 and 51.2 ± 5.59 years in non-eyebrow tattooing (NET) and ET groups, respectively (P = .78). In the ET group, soft tissue thickness was, respectively, equal to 5.90 ± 1.10 and 6.3 ± 0.95 mm on the lateral and medial side of the eyebrow, which were significantly thicker compared to the NET group (4.68 ± 0.69 and 4.78 ± 0.56 mm, respectively)(P = .001). Histopathological findings were ranging from edema-congestion to chronic inflammation and dermal fibrosis which were more frequently seen in ET group. However, this difference was statistically significant only for dermal fibrosis (P = .02). Surgical wound complications were observed in 3 patients who were in the ET group (P = .22). CONCLUSION: Subjects with eyebrow tattooing, as compared to a control group, showed a thicker eyebrow skin on ultrasonography and higher upper eyelid dermal fibrosis on histopathological examination.

Comparison of Topical Pigment Epithelium-Derived Factor (PEDF) with Topical Bevacizumab for Accelerating the Regression of Corneal Neovascularization in an Experimental Model of Rabbit Corneal Angiogenesis.

Purpose: To evaluate the anti-angiogenic effect of topical administration of Pigment epithelium-derived factor (PEDF) on the reduction of corneal neovascularization (NV) in comparison to topical Bevacizumab.Methods: 18 eyes of 18 New Zealand rabbits were enrolled. Corneal NV was induced by a 7-0 silk suture. After suture removal, rabbits were randomly divided into three groups. In every group, one eye randomly treated with topical bevacizumab or topical PEDF or saline for 14 days. The area and length of neovascularization were measured by Image J. Histological studies were done in three groups.Results: After 14 days, the mean decrease of corneal NV length was 1.84 ± 0.17 mm (P < .001) in PEDF group and 1.6 ± 0.07 mm (P < .001) in bevacizumab group which was significantly more than the saline group (P = .001 and P < .001, respectively). There was no significant difference between PEDF and bevacizumab group in the reduction of corneal NV length (P = .85). The mean decrease of corneal NV area was 4.94 ± 0.55 mm2 (P < .001) in PEDF group and 4.23 ± 0.29 mm2 in the bevacizumab group (P < .001). PEDF and bevacizumab significantly decreased corneal NV area in comparison to the saline group (p = .017, p = .001, respectively). The mean decrease of corneal NV area did not show a significant difference between PEDF and bevacizumab groups (P = .72).Conclusion: Topical PEDF might be an effective and safe treatment option as bevacizumab in a short-term use, indicating that it is as good as the standard. However, long-term effect is required to be investigated.

Increasing the efficiency of the retinoblastoma brachytherapy protocol with ultrasonic hyperthermia and gold nanoparticles: a rabbit model.

PURPOSE: This study purposed to evaluate the efficacy of brachytherapy with the modality of ultrasonic hyperthermia in the presence of gold nanoparticles (GNPs) on an ocular retinoblastoma tumor in an animal model of the rabbit. MATERIALS AND METHODS: A retinoblastoma tumor was induced by the injection of the human cell line of Y79 in rabbit eyes (n = 41). After two weeks, tumor size reached a diameter of about 5-7 mm. Seven groups were involved: control, GNPs injection, hyperthermia, hyperthermia with GNPs injection, brachytherapy with I-125, a combination of hyperthermia and brachytherapy, and a combination of brachytherapy, hyperthermia and, GNPs. The tumor area was measured using B-mode ultrasound images on the zero-day and at the end of the third week. The groups were evaluated for a histopathological study of tumor necrosis. RESULTS: There was a significant difference between the relative area changes of tumor in the combination group with the other study groups (p < .05). The results of histopathologic studies confirmed the necrosis of living retinoblastoma cells. CONCLUSION: Combination therapy of brachytherapy and hyperthermia with GNPs reduces the relative size of the tumor. This method increases the necrosis percentage of retinoblastoma and significantly reduces the retinoblastoma mass in the rabbit eyes.

Extraocular Muscle Palsy in Patients with Chronic Orbital Myositis.

BACKGROUND: Orbital myositis (OM) is a subgroup of idiopathic orbital inflammation. It can involve single or multiple extraocular muscles and result in restriction or paresis of extraocular muscles. METHOD: We reported two unusual cases of extraocular muscle paresis in the fibrotic stage of chronic OM and reviewed the literature related to this finding. RESULTS: The first case was of a 38-year-old woman with chronic OM with large-angle right eye exotropia and right medial rectus paresis. She received a botulinum A toxin injection into the right lateral rectus muscle as a first treatment, but it was unsuccessful in correcting her deviation. Subsequently, she underwent two strabismus surgeries, which successfully resolved her diplopia in primary gaze. The second case was of a 35-year-old woman with chronic OM and left lateral rectus palsy, which was managed with a botulinum A toxin injection. CONCLUSION: OM can cause extraocular muscle palsy in the chronic fibrotic stage of the disease.

Sulfur Mustard and Immunology; Trends of 20 Years Research in the Web of Science Core Collection: A Scientometric Review.

BACKGROUND: We aimed to use the scientometric approach to evaluate immunological studies on the subject of sulfur mustard over the past 20 years. METHODS: In this scientometric study, the Web of Science Core Collection was searched on the studies about sulfur mustard. The published papers related to the field of immunology were retrieved from these papers. HistCite software and VOSviewer were the applied software packages for bibliometric analysis, information visualization, and creating bibliometric networks. RESULTS: Over the past 20 years, 741 researchers from 22 countries have published 201 scientific papers in 95 journals. Iran and the United States with 93 and 68 published articles ranked at the top. The Journal of International Immunopharmacology, with 33 published papers, 439 Total Global Citation Score (TGCS), and 105 Total Local Citation Score (TLCS) was the most productive and most influential in this regard. The paper entitled "Biomonitoring of exposure to chemical warfare agents: A review" and another paper entitled "Sardasht-Iran Cohort Study of Chemical Warfare Victims: Design and Methods" were the most influential papers in this topic with 200 TGCS and 27 TLCS, respectively. The most productive and the most influential centers were "Immunoregulation Research Center of Shahed University" and "The Janbazan Medical and Engineering Research Center (JMERC)," respectively. CONCLUSION: The result of our report as the unique scientometric evaluation of the research on sulfur mustard and Immunology can be used as a roadmap for authors, researchers, and policymakers to define the best ways to allocate their financial and executive resources.

Knowledge of Laboratory Medicine in Medical Students: Is It Sufficient?

BACKGROUND & OBJECTIVE: Appropriate use of laboratory testing is essential for achieving safe and effective care to patient. Insufficient knowledge could lead to poor case management and increase the health care costs. It is believed that education on laboratory testing for undergraduate medical student is inadequate. This study was designed to evaluate the level of knowledge of 5 and 6 year undergraduate medical students in field of laboratory medicine. METHODS: Totally, 59 questions including 8 basic questions concerning individual assessment of their knowledge and 51 objective questions focusing on various stages of test ordering and interpretation were asked. RESULTS: Thirty seven undergraduate medical students at the level of internship participated. On average, 47.9% of students evaluated themselves as "weak" in 8 self-assessment questions. There was no significant difference between responders assessment on their own knowledge in various aspects of laboratory testing (P=0.184). In the objective questions regarding various stages of test ordering including pre-analytic, analytic and post analytic phases,45.6%,51.9% and 50% correct answers were reported ,respectively. Comparison of the level of the knowledge of the students regarding various stages of pathology testing did not show significant difference (P=0.638). CONCLUSION: Prioritizing an effective teaching method of laboratory medicine to medical students on appropriate time should be considered in medical school curriculum for better clinical decision making and optimal modern medical care.

Solitary neurofibroma of the orbit with intracerebral extension associated with ocular surface melanocytoma: a case report.

Solitary or isolated neurofibroma is uncommonly observed in the orbit. Neurofibromas typically involve peripheral nerves and occasionally the cranial nerves. A 29-year-old man presented with recent onset left eye proptosis and exotropia. Physical examination was positive for hyperpigmented lesions of the ipsilateral ocular surface and hard palate. Imaging revealed an infiltrative orbital mass with extension through superior orbital fissure into the brain. There was also bone defect of greater sphenoid wing. Medial orbitotomy was performed to obtain biopsies of the orbital mass and the pigmented ocular surface lesions. Histopathologic diagnosis of neurofibroma was confirmed for the former and melanocytoma for the latter. His symptoms and examinations remained stable during the follow up. This case is unique due to several features, including extensive intracerebral spread of orbital neurofibroma in a patient without definite diagnosis of neurofibromatosis type 1 and association with ipsilateral ocular surface melanocytoma and palatal pigmented lesions. ABBREVIATIONS: CT: computed tomography; GFAP: glial fibrillary acid protein; MRI: magnetic resonance imaging; NF-1: neurofibromatosis type 1.

Safety and Bioavailability of Complete and Half-Dose Intravitreal Ziv-Aflibercept in an Experimental Model: Contralateral Eye Study.

BACKGROUND AND OBJECTIVE: To evaluate the safety and bioavailability of complete and half-dose of intravitreal ziv-aflibercept (IVZ) in an experimental model. MATERIALS AND METHODS: Thirty-two eyes of 16 male rabbits received one IVZ injection under anesthesia and the operating microscope. All right and left eyes received 1,250 µg/0.05 mL and 625 µg/0.05 mL of ziv-aflibercept, respectively. Then, rabbits were randomly allocated to four groups (four rabbits in each group). The rabbits were euthanized at predesignated intervals (at 24, 168, 336, and 720 hours), and the eyes were enucleated. Indirect ophthalmoscopy, vitreous sampling, and electrophysiological recordings were obtained before euthanization. Histological examination was performed after enucleation. Vitreous samples were evaluated by enzyme-linked immunosorbent assay to measure the concentration of aflibercept. RESULTS: No serious drug-related ocular inflammation and toxicity or systemic adverse events were identified. Electroretinogram findings showed no significant difference to the baseline measurements. Remaining vitreal concentrations of ziv-aflibercept injection for the 625 µg/mL group were 416 µg/mL, 349 µg/mL, 124 µg/mL, 41.2 µg/mL, and 18.1 µg/mL (± 10 µg/mL) and for the 1,250 µg/mL group were 833 µg/mL, 737 µg/mL, 284 µg/mL, 87.3 µg/mL, and 38.2 µg/mL (± 10 µg/mL), at zero, 24, 168, 336, and 720 hours after injection, respectively. The vitreous concentration of aflibercept was analyzed by one-compartment model. The area under curve from time 0 to the end point (AUC last) was 147,637 hours × µg/mL for the complete dose group (1,250 µg/0.05mL) and 68,498 hours × µg/mL for the half-dose group (625 µg/0.05 mL). The assessed vitreous half-life of ziv-aflibercept was 113 hours in both groups. CONCLUSIONS: IVZ proved to be safe and well tolerated, even in the complete dose group. It seems to be a cost-effective therapeutic option for the treatment of retinal vascular diseases. However, the long-term safety and efficacy of intravitreal ziv-aflibercept remain unknown. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:785-790.].

Role of Schwann Cells in Preservation of Retinal Tissue Through Reduction of Oxidative Stress.

The aim of this study was to evaluate the effect of subretinal injection of Schwann cells on preservation of retina by decreasing oxidative stress in Dystrophic Royal College of Surgeons (RCS) rats. Schwann cells were harvested from the sciatic nerve of postnatal day 5, RCS rats. Twenty-five RCS rats randomly assigned to cell and sham groups. Schwann cells injected in the sub-retinal space in one eye of the cell group and carrier medium was injected in one eye of the sham group. The proof for the appropriate site of injection of Schwann cells confirmed by the green fluorescent protein (GFP) positive cells. Electroretinogram (ERG) and enucleation for histopathology and enzymatic evaluation were performed 1, 2 and 3 months post-injection. The enzymatic evaluation included catalase, superoxide dismutase (SOD) and glutathione peroxidase 1 (GPx1) by enzyme-linked immunosorbent assay (ELISA) method. Three months after injection, histopathology assessments showed a complete absence of the outer nuclear layer (ONL), photoreceptors and obvious reduction of retinal pigment epithelium (RPE) in the sham group. Cell group showed marked preservation of RPE, choroidal congestion and mild presence of ONL. The green fluorescent protein positive Schwann cells remained in one integrated layer during the study under RPE. The enzymatic evaluation showed that in cell group expression of SOD and GPx1 until month 2 and catalase until month 1 were significantly more than the sham group. At the end of month 3, the amplitude of ERG waves significantly preserved in cell group in comparison to baseline waves and the sham group. We concluded that Schwan cells are able to preserve retinal in RCS rats by reducing oxidative stress.