Study of the biological characteristics of human umbilical cord mesenchymal stem cells after long-time cryopreservation.

Human umbilical cord mesenchymal stem cells (hUC-MSCs) have considerable potential in cell therapy. Cryopreservation represents the gold standard in cell storage, but its effect on hUC-MSCs is still not well understood. The aim of this study was to investigate the effect of one year of cryopreservation and thawing on the biological characteristics of hUC-MSCs from the same donors. Fresh hUC-MSCs were cryopreserved in commercial freezing medium (serum-free CellBanker 2) at passage 2. After one year of cryopreservation, the hUC-MSCs were thawed and subcultured to passage 4. The comparison was performed in terms of followings: cell count, viability, morphology, proliferation capacity, differentiation potential and chromosomal stability. The total cell count and viability of hUC-MSCs before and after one year of cryopreservation were 1 × 107 and 96.34% and 0.943 × 107 and 93.81%, respectively. Cryopreserved and fresh hUC-MSCs displayed a similar cell doubling times, expressed the markers CD73, CD90, CD105 and were negative for the markers CD34, CD45, and HLA-DR. Karyotypes were found to be normal after one year of cryopreservation. The trilineage differentiation properties were maintained after cryopreservation. However, when compared to freshly isolated hUC-MSCs from the same donor, cryopreserved hUC-MSCs exhibited decreased expression of osteogenesis- and chondrogenesis-related genes including Runx2, Sox9, and Col1a1, and increased expression of adipogenesis-related genes. These results demonstrated that cryopreservation did not affect cell morphology, surface marker expression, cell viability, proliferative capacity, or chromosomal stability. However, the osteogenic and chondrogenic differentiation capacities of cryopreserved hUC-MSCs were slightly reduced compared with those of fresh cells from the same donor.

Functional assessment of cryopreserved clinical grade hESC-RPE cells as a qualified cell source for stem cell therapy of retinal degenerative diseases.

The biosafety and efficiency of transplanting retinal pigment epithelial (RPE) cells derived from both human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) have been evaluated in phase I and phase II clinical trials. For further large-scale application, cryopreserved RPE cells must be used; thus, it is highly important to investigate the influence of cryopreservation and thawing on the biological characteristics of hESC-RPE cells and their post-transplantation vision-restoring function. Here, via immunofluorescence, qPCR, transmission electron microscopy, transepithelial electrical resistance, and enzyme-linked immunosorbent assays (ELISAs), we showed that cryopreserved hESC-RPE cells retained the specific gene expression profile, morphology, ultrastructure, and maturity-related functions of induced RPE cells. Additionally, cryopreserved hESC-RPE cells exhibited a polarized monolayer, tight junction, and gap junction structure and an in vitro nanoparticle phagocytosis capability similar to those of induced hESC-RPE cells. However, the level of pigment epithelium-derived factor (PEDF) secretion was significantly decreased in cryopreserved hESC-RPE cells. Royal College of Surgeons rats with cryopreserved hESC-RPE cells engrafted into the subretinal space exhibited a significant decrease in the b-wave amplitude compared with rats engrafted with induced hESC-RPE cells at 4 weeks post transplantation. However, the difference disappeared at 8 weeks and 12 weeks post operation. No significant difference in the outer nuclear layer (ONL) thickness was observed between the two groups. Our data showed that even after cryopreservation and thawing, cryopreserved hESC-RPE cells are still qualified as a donor cell source for cell-based therapy of retinal degenerative diseases.

PSCs Reveal PUFA-Provoked Mitochondrial Stress as a Central Node Potentiating RPE Degeneration in Bietti's Crystalline Dystrophy.

Bietti's crystalline dystrophy (BCD) is an incurable retinal disorder caused by the polypeptide 2 of cytochrome P450 family 4 subfamily V (CYP4V2) mutations. Patients with BCD present degeneration of retinal pigmented epithelial (RPE) cells and consequent blindness. The lack of appropriate disease models and patients' RPE cells limits our understanding of the pathological mechanism of RPE degeneration. In this study, using CYP4V2 mutant pluripotent stem cells as disease models, we demonstrated that RPE cells with CYP4V2 mutations presented a disrupted fatty acid homeostasis, which were characterized with excessive accumulation of poly-unsaturated fatty acid (PUFA), including arachidonic acid (AA) and eicosapentaenoic acid (EPA). The PUFA overload increased mitochondrial reactive oxygen species, impaired mitochondrial respiratory functions, and triggered mitochondrial stress-activated p53-independent apoptosis in CYP4V2 mutant RPE cells. Restoration of the mutant CYP4V2 using adeno-associated virus 2 (AAV2) can effectively reduce PUFA deposition, alleviate mitochondria oxidative stresses, and rescue RPE cell death in BCD RPE cells. Taken together, our results highlight a role of PUFA-induced mitochondrial damage as a central node to potentiate RPE degeneration in BCD patients. AAV2-mediated gene therapy may represent a feasible strategy for the treatment of BCD.

Efficacy and Safety of Autologous Bone Marrow Mesenchymal Stem Cell Transplantation in Patients with Diabetic Retinopathy.

BACKGROUND/AIMS: The treatment options for diabetic retinopathy (DR) are limited. Mesenchymal stem cells (MSCs) are a promising treatment option for diabetes and its complications. In this pilot clinical trial, we evaluated the safety and efficacy of intravenous autologous bone marrow MSCs (ABMSC) for the treatment of DR. METHODS: In total, 34 eyes with non-proliferative or proliferative DR (NPDR, n = 19; PDR, n = 15) from 17 patients were analyzed. Treatment involved one intravenous infusion of 3 × 106/kg ABSMCs. The patients' vital signs were monitored, along with immune and allergic reactions. Treatment efficacy was evaluated via measurements of the following parameters at baseline, and at 1, 3, and 6 months after treatment: the levels of fasting blood glucose (FBG), Hemoglobin A1C (HbA1C), interleukin-6 (IL-6), and hypersensitive C-reactive protein (CRP); best corrected visual acuity (BCVA); and central macular and subfield thickness (via optical computed tomography). RESULTS: ABMSC infusion led to a significant decrease in FBG and CRP levels (P < 0.05). There were no significant differences in HbA1C or IL-6 levels. Sub-group analysis revealed that only eyes in the NPDR group had the macular thickness reductions and a significant improvement in BCVA from baseline (P = 0.006 at 3 months and 0.027 at 6 months), while those in the PDR group did not. There were no acute reactions during the treatment or severe adverse events during the follow-up period. CONCLUSION: ABSMCs are a potentially safe and effective treatment option for DR, and the optimum therapeutic window appears to be during the NPDR stage.

Detecting novel genetic mutations in Chinese Usher syndrome families using next-generation sequencing technology.

Usher syndrome (USH) is the most common cause of combined blindness and deafness inherited in an autosomal recessive mode. Molecular diagnosis is of great significance in revealing the molecular pathogenesis and aiding the clinical diagnosis of this disease. However, molecular diagnosis remains a challenge due to high phenotypic and genetic heterogeneity in USH. This study explored an approach for detecting disease-causing genetic mutations in candidate genes in five index cases from unrelated USH families based on targeted next-generation sequencing (NGS) technology. Through systematic data analysis using an established bioinformatics pipeline and segregation analysis, 10 pathogenic mutations in the USH disease genes were identified in the five USH families. Six of these mutations were novel: c.4398G > A and EX38-49del in MYO7A, c.988_989delAT in USH1C, c.15104_15105delCA and c.6875_6876insG in USH2A. All novel variations segregated with the disease phenotypes in their respective families and were absent from ethnically matched control individuals. This study expanded the mutation spectrum of USH and revealed the genotype-phenotype relationships of the novel USH mutations in Chinese patients. Moreover, this study proved that targeted NGS is an accurate and effective method for detecting genetic mutations related to USH. The identification of pathogenic mutations is of great significance for elucidating the underlying pathophysiology of USH.

[Contributions of human rods and cones pathway to different components of oscillatory potentials in time and frequency domain].

OBJECTIVE: To investigate the contributions of human rods and cones pathway to different components of oscillatory potentials (OP) in time and frequency domain. METHODS: Case-control study. Twenty subjects were divided into two groups, normal groups (NG) and cones pathway abnormal groups (CAG). All eyes were investigated by dark-adapted (DA) and light-adapted (LA) 3.0 ERG recommended by ISCEV. Data were output into the computer and processed and analyzed by the software Matlab7.0. First, to extract the OP by filter, then to get the frequency-amplitude relationship by FFT, after that the relationship was fitted by equations and lastly we statistic and analyze the parameters gotten from the equations. RESULTS: Compared with normal group [(48.63 ± 4.29), (158.00 ± 32.75), (69.27 ± 30.31), (38.5 ± 15.28) µV], the amplitudes of the first two components of dark-adapted OP in the CAG [(4.12 ± 3.20), (71.25 ± 25.43), (48.96 ± 20.05), (36.84 ± 14.26) µV] were significant decreased (t = 16.68, 5.77, P < 0.01). Frequency domain of LA and DA OP in the two groups was comprised with two components (harmonic and subharmonic). Compared with normal group, harmonic components of CAG were dramatic decreased (t = 2.72, P < 0.05; Z = -2.24, P < 0.05). The value of subharmonic component in CAG was lowest in DA OP compared with NG (t = 4.20, P < 0.005). CONCLUSIONS: Cones and rods pathway all contributed to the DA and LA OP Cones pathway mainly contributes to the earlier and faster components of OP while the rods pathway to the later and slower components.

[Quantitative assess the efficacy of congenital idiopathic nystagmus surgery by digital eye tracker].

OBJECTIVE: To evaluate the feasibility of independently developed digital eye tracker in determining the efficacy of congenital idiopathic nystagmus (CIN) surgery. METHODS: Aprospective selfpairing study. The surgical efficacy was evaluated by independently developed eye tracker in 16 CIN patients. The null zone and the frequency, amplitude, intensity of nystagmus in various gazing position were recorded with eye tracker pre and post operatively. The consistency of null zone determined by digital eye tracker and clinical investigation were evaluated. The preoperative and postoperative rectification of horizontal and vertical nystagmus in the horizontal direction of individual patient were compared by paired samples t-test. The improvement or aggravation quantity were recorded by comparing preoperative and postoperative intensity of nystagmus every 5° within 25°. RESULT: The null zone got from digital eye tracker and clinical investigation were highly consistent (r = 0.952, P < 0.01). The horizontal and vertical intensity improved in 9 patients (t = 2.335-6.609, P < 0.05) and 5 patients (t = 2.176-5.471, P < 0.05) respectively after surgery. There were 67.63% (117/173) horizontal intensity and 69.94% (121/173) vertical intensity improvement. CONCLUSION: The independently developed digital eye tracker can quantitatively evaluate the pre and post-operative nystagmus and analyze the surgical efficacy for CIN patients.

Incidence of retinopathy of prematurity in southwestern China and analysis of risk factors.

BACKGROUND: The aim of this study was to screen for retinopathy of prematurity (ROP) in southwestern China and understand the prevalence and risk factors of ROP, which may provide evidence useful in the prevention and treatment of ROP. MATERIAL/METHODS: 1864 preterm infants (gestational age of <37 weeks and birth weight of ≤2500 g) underwent ROP screening from January 2009 to November 2012 in Southwest China. The medical information of infants during perinatal period was reviewed, and risk factors of ROP were determined. A total of 1614 infants were recruited for final analysis. RESULTS: Incidence of ROP was 12.8%. The first, second, third, and fourth stage of ROP was found in 64.6%, 29.6%, 3.4%, and 0.5% of infants, respectively. No fifth stage of ROP was observed. In addition, 7.7% of infants required surgical intervention. In our Department of Neonatology, the incidence of ROP was 20.0%, which was significantly higher than in non-hospitalized patients (9.9%). The incidence of ROP remained unchanged over the years. Independent risk factors of ROP included low birth weight (p=0.049), low gestational age (p=0.008), days of oxygen supplementation (p=0.008), and myocardial injury after birth (p=0.001). CONCLUSIONS: The prevalence of ROP in preterm infants is relatively high in Southwest China, and low birth weight, low gestational age, days of oxygen supplementation, and myocardial injury after birth are independent risk factors for ROP.

Clinical manifestation and long-term follow-up of presumed ocular tuberculosis in China.

Background: This study aimed to report the clinical manifestations of presumed ocular tuberculosis (OTB) and the treatment response after anti-tuberculosis therapy (ATT) in a Chinese population. Methods: Clinical data, including general characteristics, ocular lesions, visual acuity at baseline, and final follow-up of patients with presumed OTB from 2006 to 2022 in two eye clinics in China, were retrospectively analyzed. Results: The study included 84 eyes of 52 patients. The following ocular manifestations were observed: anterior uveitis (4.8%), posterior uveitis (34.5%), panuveitis (11.9%), retinal vasculitis (40.5%) and optic neuropathy (8.3%). After ATT, the vision improved by varying degrees in 48 eyes (57.1%), remained stable in 34 eyes (40.5%) and decreased in 2 eyes (2.4%). Conclusions: OTB is likely to be misdiagnosed as other infectious uveitis and optic neuropathy. Clinical features must be interpreted in conjunction with topical and general laboratory findings and in collaboration with other subspecialties to make a final diagnosis.

Light-evoked currents in retinal ganglion cells from dystrophic RCS rats.

PURPOSE: To study the electrophysiological properties of the light-evoked currents in ganglion cells in situations of retinal degeneration. METHODS: We investigated light-evoked currents in ganglion cells by performing whole-cell patch-clamp recordings from ganglion cells using a retina-stretched preparation from Royal College of Surgeons (RCS) rats, a model of retinal degeneration and congenic controls at different ages. Pharmacological inhibitors of the AMPA receptor (NBQX), GABA receptor (BMI), and sodium channels (TTX) were used to identify the components of the light-evoked currents in ON, OFF and ON-OFF retinal ganglion cells. RESULTS: We found that the light-evoked currents in ganglion cells from control rats were inhibited by NBQX, BMI and TTX, suggesting that AMPA receptors, GABA receptors and sodium channels contribute to these currents in ganglion cells. However, only AMPA receptor-mediated currents were recorded in RCS rats. Light-evoked inward currents were absent in the majority of ganglion cells from RCS rats, particularly at the later stages of retinal degeneration. At earlier stages of retinal degeneration, we found that both the timing and amplitude of light-evoked currents are significantly different in ganglion cells from RCS and control rats. CONCLUSIONS: Our study furthers the understanding of the electrophysiological characteristics of retinal ganglion cells during retinal degeneration, and provides insight into the optimal timing for the treatment of retinal degeneration.

[Importance of multifocal electroretinogram in diagnosis of macular diseases].

Because multifocal electroretinogram can be used to assess the function of posterior pole of the retina especially in the macula objectively, non-invasively and quantitatively, it was widely used in clinic. At present, more practical experience of clinical visual electrophysiological testing has been obtained and achieved, but there are still some questions such as standardization of the operation, combined diagnosis of morphology and function of macular diseases, follow-up visit and investigation of macular diseases. Therefore, the value of the visual electrophysiology especially multifocal technique in diagnosis of macular diseases was not fully embodied. No matter the development or the operation of the mutifocal system should be strictly followed by the standards of International Society of Clinical Electrophysiology for Vision. Functional changes would be observed before the morphological changes in some macular disease especially early stage of the diseases by the help of multifocal electrophysiological test. Also this test can be used to assess the macular function in some macular diseases that showed disaccord between functional and morphological changes. Furthermore, diseases of optic nerve and visual cortex would be investigated by expanding the use of multifocal technique such as new analysis methods, new test methods and research on the animal models which would help to understand more about the mechanisms and therapeutic approaches of ophthalmic diseases.

[How to use of visual evoked potential testing technology reasonable].

Visual evoked potential testing items depend on stimuli and recording parameters. There is great variation in flash visual evoked potential (FVEP), while the pattern visual evoked potential (PVEP) is stable. The later is taken as the main objective assessment of visual function indicators in clinical. Only when PVEP cannot be recorded or the waves are hard to be recognized, the FVEP will be a reference indicator. There is less clinical meaning to do FVEP testing alone. Recommended visual evoked potential and electroretinogram in combination will be more comprehensive response visual function.If it is necessary, electrooculogram, multifocal electroretinogram, pattern electroretinogram should apply to test together in some case. Multifocal visual evoked potential (mfVEP) were developed to record local field response, such as the early field change in glaucoma. The mfVEP is not a small version of the conventional visual evoked potential, since the generated source in both is different. The waves of mfVEP are related to the stimulation (spatial, temporary and contrast), recording channel (single, double or four), and method for signal extracting and signal nose ration. It is a potential objective assessment method for retinal ganglion cell or optic nerve and still needs further improvement. There will be variable and fluctuation in any visual electrophysiological testing results, the explanation for the results should be relay on complains, symptom, signs and other laboratory examination results.

[Studies on glial isomerization of lamina cribrosa in rat].

OBJECTIVE: To explore the mechanism of optic nerve damage in glaucoma by study on structure of glial lamina cribrosa(LC) in rats. METHODS: Experimental study. Albino Swiss(AS) rats were divided into 3 groups. Bilateral eyes of 10 normal rats were employed to be group I (right eye ) and group II (left eye) . Group III was from the left eyes of 13 rats underwent artificially intraocular hypertension in the right eyes. All rats were perfused and fixed with electronic microscopy fixative (2% paraformaldehyde +2% glutaraldehyde). Trimmed optic nerves were embedded with resin. Serial 1.5 µm thick 'semithin' sections were cut, either (2 eyes from group III) longitudinally, through the optic nerve head (ONH) from the retinal end to the commencement of the optic nerve, or (31 eyes) transversely (cross-sections). Ultrathin sections were cut in the middle of glial LC. The morphological observation of glial LC was obtained by light microscopy and transmission electron microscopy. Bonferroni correction was used to counteract the multiple comparison of each group. RESULTS: Fortified astrocytes formed the main supportive structure of glial LC in all rats, including group I, group II and group III. Astrocytes were ranked as a fan-like radial array, firmly attached ventrally to the sheath of the LC by thick basal processes, but dividing dorsally into progressively more slender processes with only delicate attachments to the sheath. These fortified astrocytes form ventral stout basal end feet, radial array, axon free-'preterminal' layer before terminating in a complex layer of fine interdigitating delicate branches at the dorsal. LC astrocytes were highly and uniformly electron dense throughout all the cell processes. An equally striking feature of the astrocytic processes was their massive cytoskeletal 'strengthening' of longitudinal massed filaments and tubules. Especially, massive filaments accumulated as cytoskeletal cores to form 'scaffold' of fortified astrocytes. There was vulnerable area in the dorsal of glial LC. This vulnerable area was isomerisation in bilateral eyes and different rats. There was different space in the vulnerable area. These space could be divided into 3 grades, (-), (+) and (++) . The number of (-), (+) and (++)were 1, 6, 3 eyes in group I, 1, 5, 4 eyes in group II, 1, 7, 3 eyes in group III. The Kruskal-Wallis test was used for statistical evaluations. There was no statistical differences of the ratio of (-), (+) and (++) in group I, group II and group III(χ(2) = 3.35, P = 0.187>0.05;group I vs group II, Z = -1.048, P = 0.294;group I vs group III Z = -1.691, P = 0.091;group II vs group III,Z = -1.343, P = 0.179). The ratio of space (-)was significantly less than space (+) and space (++) in group I, group II and group III(χ(2) = 23.88, P < 0.05; (-) vs (+) , Z = -2.821, P = 0.005; (-) vs (++) , Z = -2.726, P = 0.006). The ratio of space (+)was much more than space (++) in group I, group II and group III(Z = -4.410, P < 0.05). CONCLUSION: Glial isomerisation in LC may play a key role in glaucomatous optic nerve damage.

[Prevalence and causes of blindness and moderate and severe visual impairment among adults aged 50 years or above in Yongchuan District of Chongqing City: the China Nine-Province survey].

OBJECTIVE: To investigate the prevalence and causes of blindness and moderate and severe visual impairment among adults aged 50 years or above in Yongchuan of Chongqing City, China. METHODS: It was a population-based cross-section study.Geographically defined cluster sampling was used in randomly selecting 5663 individuals aged ≥ 50 years in Yongchuan District. The survey was preceded by a pilot study where operational methods were refined and quality assurance evaluation was carried out. All participants were enumerated through village registers followed door-to-door visits.Eligible individuals were invited to receive visual acuity measurement and eye examination. Prevalence of blindness and moderate and severe visual impairment was calculated according to different age, gender or education. And the reasons of blindness were analyzed.Statistical analyses were performed using Stata/SE Statistical Software, release 9.0. Chi-square test was used to investigate the association of age, gender and education with presenting and best corrected visual acuity. RESULTS: Five thousands six hundreds and sixty-three individuals were enumerated and 5390 persons were examined, the response rate was 95.18%. Based on the criteria of World Health Organization visual impairment classification in 1973, the prevalence of blindness and moderate and severe visual impairment defined as best corrected visual acuity was 2.12% (114/5390) and 5.40% (291/5390) respectively. The prevalence of blindness and moderate and severe visual impairment defined as presenting visual acuity was 2.49% (134/5390) and 10.71% (577/5390) respectively. The prevalence of blindness and moderate and severe visual impairment was higher in aged (trend χ(2) = 951.32, P = 0.000) , female (χ(2) = 33.35, P = 0.000) and illiterate (trend χ(2) equals; 141.32, P = 0.000) persons. Cataract was still the first leading cause of blindness and visual impairment.Un-corrected refractive error also was the main cause of visual impairment. CONCLUSIONS: The prevalence of blindness and moderate and severe visual impairment is relatively higher among older adults aged 50 years or above in Yongchuan District. The first leading cause of blindness and visual impairment is still cataract.

[Clinical characteristics of paraneoplastic retinopathy and optic neuropathy].

OBJECTIVE: To analyze the clinical characteristics of paraneoplastic retinopathy and optic neuropathy(PRON). METHODS: Case series study. Eight patients were enrolled from October 2006 to March 2012 visited in ophthalmology department, the People Liberation Army General Hospital. The patients were underwent a series of examinations, including fundus photography, visual electrophysiology, fundus fluorescein angiography, optic coherent tomography,fundus autofluorescent imaging, perimetry, ultrasonography, magnetic resonance imaging, spinal tap and cerebrospinal fluid test, paraneoplastic syndrome (PNS) antibody test. The patients were followed up in outpatient department and(or) by phone. The clinical manifestation,entity types, and treatment were analyzed. RESULTS: Of the eight patients, there were cancer associated retinopathy(CAR) 3 cases, bilateral diffuse uveal melanocytic proliferation (BDUMP) 2 cases and paraneoplastic optic neuropathy(PON) 3 cases. Five patients were detected the PNS antibodies and revealed three patients with positive results. As for the primary malignancy,four of the eight patients were lung carcinoma,others included invasive thymoma, kidney cancer, acute lymphocytic leukemia and cervical cancer, each for one case. All the patients complained vision blurring or progressive visual decrease. Other complaints included dark shadow in two patients, shimmering, dazzling, double vision and eye pain, each in one patient. One patient complained progressive decreased vision in both eyes prior to the diagnosis of lung cancer. Of the 16 eyes of the eight patients, there were six patients with no light perception vision, five from light perception to 0.05, and other five with no less than 0.4 vision, in the end of the follow up. Five patients were treated with steroid with unsatisfactory efficacy. CONCLUSIONS: Each entity of PRON has its own clinical characteristics. PRON especially BDUMP may be a pre-metastatic disease.

Chromatic pupillometry isolation and evaluation of intrinsically photosensitive retinal ganglion cell-driven pupillary light response in patients with retinitis pigmentosa.

Purpose: The pupil light response (PLR) is driven by rods, cones, and intrinsically photosensitive retinal ganglion cells (ipRGCs). We aimed to isolate ipRGC-driven pupil responses using chromatic pupillometry and to determine the effect of advanced retinitis pigmentosa (RP) on ipRGC function. Methods: A total of 100 eyes from 67 patients with advanced RP and 18 healthy controls (HCs) were included. Patients were divided into groups according to severity of visual impairment: no light perception (NLP, 9 eyes), light perception (LP, 19 eyes), faint form perception (FFP, 34 eyes), or form perception (FP, 38 eyes). Pupil responses to rod-weighted (487 nm, -1 log cd/m2, 1 s), cone-weighted (630 nm, 2 log cd/m2, 1 s), and ipRGC-weighted (487 nm, 2 log cd/m2, 1 s) stimuli were recorded. ipRGC function was evaluated by the postillumination pupil response (PIPR) and three metrics of pupil kinetics: maximal contraction velocity (MCV), contraction duration, and maximum dilation velocity (MDV). Results: We found a slow, sustained PLR response to the ipRGC-weighted stimulus in most patients with NLP (8/9), but these patients had no detectable rod- or cone-driven PLR. The ipRGC-driven PLR had an MCV of 0.269 ± 0.150%/s and contraction duration of 2.562 ± 0.902 s, both of which were significantly lower than those of the rod and cone responses. The PIPRs of the RP groups did not decrease compared with those of the HCs group and were even enhanced in the LP group. At advanced stages, ipRGC responses gradually became the main component of the PLR. Conclusion: Chromatic pupillometry successfully isolated an ipRGC-driven PLR in patients with advanced RP. This PLR remained stable and gradually became the main driver of pupil contraction in more advanced cases of RP. Here, we present baseline data on ipRGC function; we expect these findings to contribute to evaluating and screening candidates for novel therapies.

Organoid-derived human retinal progenitor cells promote early dedifferentiation of Müller glia in Royal College of Surgeons rats.

AIM: To explore whether the subretinal transplantation of retinal progenitor cells from human embryonic stem cell-derived retinal organoid (hERO-RPCs) could promote Müller glia dedifferentiation and transdifferentiation, thus improving visual function and delaying retinal degenerative progression. METHODS: hERO-RPCs were subretinally transplanted into Royal College of Surgeons (RCS) rats. Electroretinography (ERG) recording was performed at 4 and 8wk postoperation to assess retinal function. Using immunofluorescence, the changes in outer nuclear layer (ONL) thickness and retinal Müller glia were explored at 2, 4, and 8wk postoperation. To verify the effect of hERO-RPCs on Müller glia in vitro, we cocultured hERO-RPCs with Müller glia with a Transwell system. After coculture, Ki67 staining and quantitative polymerase chain reaction (qPCR) were performed to measure the proliferation and mRNA levels of Müller glia respectively. Cell migration experiment was used to detect the effect of hERO-RPCs on Müller glial migration. Comparisons between two groups were performed by the unpaired Student's t-test, and comparisons among multiple groups were made with one-way ANOVA followed by Tukey's multiple comparison test. RESULTS: The visual function and ONL thickness of RCS rats were significantly improved by transplantation of hERO-RPCs at 4 and 8wk postoperation. In addition to inhibiting gliosis at 4 and 8wk postoperation, hERO-RPCs significantly increased the expression of dedifferentiation-associated transcriptional factor in Müller glia and promoted the migration at 2, 4 and 8wk postoperation, but not the transdifferentiation of these cells in RCS rats. In vitro, using the Transwell system, we found that hERO-RPCs promoted the proliferation and migration of primary rat Müller glia and induced their dedifferentiation at the mRNA level. CONCLUSION: These results show that hERO-RPCs might promote early dedifferentiation of Müller glia, which may provide novel insights into the mechanisms of stem cell therapy and Müller glial reprogramming, contributing to the development of novel therapies for retinal degeneration disorders.

Prevalence of eye diseases and causes of visual impairment in school-aged children in Western China.

BACKGROUND: The present study investigated the prevalence of refractive error, visual impairment, and eye diseases in school-aged children in western China. METHODS: The survey was done in a representative county (Yongchuan District, Chongqing Municipality) of western China. Cluster random sampling was used to select children aged 6 to 15 years. We conducted door-to-door surveys and eye examinations including optometry, stereoscopic vision test, eye position and eye movement, slit lamp examination of the anterior segment, retinoscopy, and fundus examination after cycloplegia with 1% cyclopentolate. RESULTS: Among 3469 children, data were available for 3079 (88.76%). The prevalences of eye diseases were, in descending order, refractive error (20.69%; 637/3079), conjunctivitis (11.76%; 362/3079), amblyopia (1.88%; 58/3079), color vision defect (0.52%; 16/3079), keratitis (0.36%; 11/3079), strabismus (0.29%; 9/3079), cataract (0.23%; 7/3079), pathologic myopia (0.19%; 6/3079), and ocular trauma (0.13%; 4/3079). The prevalence of corneal leucoma, corneal staphyloma, optic neuropathy, macular degeneration, and myelinated nerve fibers was 0.03% (1/3079) for each. The prevalence of visual impairment was 7.70% (237/3079), and the major causes of visual impairment were uncorrected refractive error (86.08%; 204/237), amblyopia (9.70%; 23/237), pathologic myopia (1.27%; 3/237), congenital cataract (0.42%; 1/237), and others (2.11%; 5/237). CONCLUSIONS: Among school-aged children in a less developed area of western China, refractive error was the most prevalent eye disorder, and uncorrected refractive error was the main cause of visual impairment.

Visual task-related functional and structural magnetic resonance imaging for the objective quantitation of visual function in patients with advanced retinitis pigmentosa.

Purpose: The objective quantitation of visual function in patients with advanced retinitis pigmentosa (RP) presents a difficult challenge due to the weak visual function of these patients. This study utilized magnetic resonance imaging (MRI) to assess the function and structure of the visual cortex (VC) in patients with RP and quantitatively categorize them. Materials and Methods: Twenty-three patients with RP and ten healthy controls (HCs) were enrolled for MRI examinations. The patients were divided into form perception (FP) and no form perception (NFP) groups. Participants underwent structural MRI scans, and two visual task functional MRI scans were performed using stimuli, including white flash and black and white checkerboard patterns. Eight regions of interest (ROIs) were studied. In structural MRI, the gray matter volume (GMV) was compared in the ROIs. In the two visual tasks, the response intensity and functional connectivity (FC) of ROIs were also compared separately. Correlation analysis was performed to explore the correlations between the structural and functional parameters. Results: In the structural analysis, the GMV in Brodmann areas 17, 18, and 19 of the FP and NFP groups was significantly lower than that of HCs. Regarding the functional data, the response intensity in the VC of both the FP and NFP groups was significantly lower than that in HCs. The response in Brodmann areas 17, 18, and 19 obtained using the pattern stimulus was significantly lower in the NFP group than in the FP group. For the FC comparison, the FP and NFP groups exhibited significantly lower values in several pathways than the HCs, and FC in the ipsilateral V1-contralateral V1 pathway in the flash task was significantly lower in the NFP group than in the FP group. A positive correlation between response intensity and GMV was observed in Brodmann areas 17, 18, and 19 in both flash and pattern visual tasks. Conclusion: Magnetic resonance imaging was an effective tool to objectively and quantitatively evaluate the visual function of patients with advanced RP. Response intensity and FC were effective parameters to distinguish FP and NFP patients. A positive correlation between response intensity and GMV was observed in the VC.

Functional Deficits and Structural Changes Associated With the Visual Attention Network During Resting State in Adult Strabismic and Anisometropic Amblyopes.

Our previous study has shown impaired blood oxygen level-dependent (BOLD)/functional magnetic resonance imaging (fMRI) activation of the visual attention network in strabismic amblyopia (SA). However, there has been no comparison of resting state fMRI activation and functional connectivity (FC) in brain regions of interest (ROIs) along the visual attention network including visual cortex (V1), intraparietal sulcus (IPS), and frontal eye fields (FEFs) during closed eye resting across the SA (n = 20, 13LE), or anisometropic amblyopes (AA) (n = 20, 13LE) groups. Hence, we compared, gray matter volume (GMV), amplitude of low frequency fluctuations (ALFFs), regional homogeneity (ReHo), and FC in the left and right hemisphere ROIs of the visual attention network in SA, AA, and healthy controls (HCs) (n = 21). Correlation analyses of corrected visual acuity (cVA) of amblyopic eye and MRI results were also performed and showed that the LogMAR cVA of the amblyopic eye positively correlated with right zALFF and zReHo FEF of SA and right IPS of AA only. GMV of both left and right hemisphere V1 areas was significantly greater but ALFF was significantly lower for SA compared to AA and HC groups. zALFF and zReHo analyses in the AA and SA groups indicated significantly higher activation than that in the HC group in the right FEF and IPS but lower than that in the HC group in the left FEF, and only the SA group showed lower activation in both V1 areas than the HC group. FC values of the right FEF-left V1, right FEF-right V1, and right FEF-right IPS pathways in the SA and AA groups were also significantly higher than those in the HC group whereas all other FC values were non-significant. Thus, this study indicates that even during resting-state the visual attention network function is impaired in SA and AA participants with only right hemisphere FEF showing significant activation in SA and IPS in AA suggesting that the slower saccade activation times characteristic of amblyopic eyes lead to the dominant eye controlling activation of the visual attention network.