RESUMO
Mesenchymal stem cells are widely used in many pre-clinical and clinical settings. Despite advances in molecular technology; the migration and homing activities of these cells in in vivo systems are not well understood. Labelling mesenchymal stem cells with gold nanoparticles has no cytotoxic effect and may offer suitable indications for stem cell tracking. Here, we report a simple protocol to label mesenchymal stem cells using 80 nm gold nanoparticles. Once the cells and particles were incubated together for 24 h, the labelled products were injected into the rat subretinal layer. Micro-computed tomography was then conducted on the 15th and 30th day post-injection to track the movement of these cells, as visualized by an area of hyperdensity from the coronal section images of the rat head. In addition, we confirmed the cellular uptake of the gold nanoparticles by the mesenchymal stem cells using transmission electron microscopy. As opposed to other methods, the current protocol provides a simple, less labour-intensive and more efficient labelling mechanism for real-time cell tracking. Finally, we discuss the potential manipulations of gold nanoparticles in stem cells for cell replacement and cancer therapy in ocular disorders or diseases.
Assuntos
Olho/diagnóstico por imagem , Ouro , Células-Tronco Mesenquimais/metabolismo , Nanopartículas Metálicas , Microtomografia por Raio-X , Animais , Biomarcadores , Rastreamento de Células , Ouro/química , Imunofenotipagem , Células-Tronco Mesenquimais/citologia , Nanopartículas Metálicas/química , Fenótipo , RatosRESUMO
OBJECTIVE: To evaluate the retinal nerve fiber layer (RNFL) and macular thicknesses and identify systemic risk factors for thinning of these layers in patients with metabolic syndrome (MetS). METHODOLOGY: A cross-sectional observational study was performed on patients diagnosed with MetS and compared to normal controls. All patients underwent ophthalmic and anthropometric examination, serological and biochemical blood investigations; and ocular imaging using spectral-domain optical coherence tomography. Patients with ocular pathology were excluded. Unpaired t-test was used to compare mean thickness between the two groups. One-way ANOVA with Bonferroni correction for multiple comparisons was used to compare mean thickness between different tertiles of MetS parameters, and a generalized estimating equation was used to correct for inter-eye correlation and to assess association between mean thickness and covariates. RESULTS: Two hundred and forty-eight eyes from 124 participants (1:1 ratio of MetS patients to controls) were included. Age ranged between 30 to 50 years old, and mean age was 40 ± 6.6 years. RNFL thickness was lower globally (93.6 ± 9.9 µm vs 99.0 ± 9.3, p<0.001) and in the inferior (124.5 ± 17.5 µm vs 131.0 ± 16.4 µm, p = 0.002), superior (117.2 ± 16.0 µm vs 126.3 ± 14.4 µm, p<0.001) and temporal (65.5 ± 10.2 µm vs 69.5 ± 9.8, p = 0.002) sectors in MetS patients compared to controls. Only the central (237.0 ± 14.0 µm vs 243.6 ± 18.0 µm, p = 0.002) and inferior parafoveal (307.8 ± 20.9 vs 314.6 ± 14.6, p = 0.004) area of the macula was significantly thinner. The inferior RNFL sector had the most difference (mean difference = 9.1 µm). The Generalized Estimating Equation found that, after adjusting for age, diastolic blood pressure, BMI, HDL and obesity; the number of MetS components and elevated triglyceride levels were independent risk factors for reduced thickness in global RNFL (ß = -4.4, 95% CI = -7.29 to -1.5, p = 0.003) and inferior parafovea (ß = -6.85, 95% CI = -11.58 to -2.13, p = 0.004) thickness respectively. CONCLUSION: RNFL thinning was seen more than macula thinning in MetS patients, suggesting RNFL susceptibility to neurodegeneration than the macula. A higher number of metabolic components and elevated triglyceride levels were independent risk factors for retinal thinning in this group of patients.
Assuntos
Macula Lutea/diagnóstico por imagem , Síndrome Metabólica/diagnóstico por imagem , Fibras Nervosas/patologia , Neurônios Retinianos/patologia , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia de Coerência ÓpticaRESUMO
Retinal disorders account for a large proportion of ocular disorders that can lead to visual impairment or blindness, and yet our limited knowledge in the pathogenesis and choice of appropriate animal models for new treatment modalities may contribute to ineffective therapies. Although genetic in vivo models are favored, the variable expressivity and penetrance of these heterogeneous disorders can cause difficulties in assessing potential treatments against retinal degeneration. Hence, an attractive alternative is to develop a chemically-induced model that is both cost-friendly and standardizable. Sodium iodate is an oxidative chemical that is used to simulate late stage retinitis pigmentosa and age-related macular degeneration. In this study, retinal degeneration was induced through systemic administration of sodium iodate (NaIO3) at varying doses up to 80â¯mg/kg in Sprague-Dawley rats. An analysis on the visual response of the rats by electroretinography (ERG) showed a decrease in photoreceptor function with NaIO3 administration at a dose of 40â¯mg/kg or greater. The results correlated with the TUNEL assay, which revealed signs of DNA damage throughout the retina. Histomorphological analysis also revealed extensive structural lesions throughout the outer retina and parts of the inner retina. Our results provided a detailed view of NaIO3-induced retinal degeneration, and showed that the administration of 40â¯mg/kg NaIO3 was sufficient to generate disturbances in retinal function. The pathological findings in this model reveal a degenerating retina, and can be further utilized to develop effective therapies for RPE, photoreceptor, and bipolar cell regeneration.
Assuntos
Iodatos/toxicidade , Retina/efeitos dos fármacos , Degeneração Retiniana/patologia , Animais , Apoptose/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Modelos Animais de Doenças , Eletrorretinografia , Ratos , Ratos Sprague-Dawley , Retina/patologia , Retina/fisiologiaRESUMO
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 3â¯×â¯105 DPSCs as well as a single systemic administration of NaIO3 (40â¯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 4â¯weeks, which was statistically significant (* Pâ¯≤â¯.05) compared to the control. Retinal thickness of the control was also found to be thinner (*** Pâ¯≤â¯.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.
Assuntos
Iodatos/toxicidade , Transplante de Células-Tronco Mesenquimais , Degeneração Retiniana/terapia , Epitélio Pigmentado da Retina/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Polpa Dentária/citologia , Modelos Animais de Doenças , Eletrorretinografia , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Células Fotorreceptoras/citologia , Ratos , Ratos Sprague-Dawley , Degeneração Retiniana/etiologia , Epitélio Pigmentado da Retina/patologiaRESUMO
We discuss the diagnostic challenge in an adult patient presented with purely ocular symptoms diagnosed with tuberculous meningitis (TBM). A 38-year-old woman presented with bilateral painless blurring of vision. There were bilateral sixth cranial nerve palsy and bilateral optic disc swelling. Optic nerve function tests were normal. Patient was lucid with no signs of meningism. Brain imaging were normal. She had a positive Mantoux test, high erythrocyte sedimentation rate but no clinical evidence of active pulmonary tuberculosis infection. Her Quantiferon-TB Gold in-tube test was negative. Cerebrospinal fluid analysis revealed a high opening pressure but no biochemical parameters to suggest TBM, hence she was treated as idiopathic intracranial hypertension. A diagnosis of TBM was finally made following a positive PCR for Mycobacterium tuberculosis Her vision improved with reduction in optic disc swelling following antituberculous treatment.
Assuntos
Tuberculose Meníngea/diagnóstico , Adulto , Antituberculosos/administração & dosagem , Antituberculosos/uso terapêutico , Diagnóstico Diferencial , Esquema de Medicação , Feminino , Humanos , Papiledema/tratamento farmacológico , Tuberculose Meníngea/complicações , Tuberculose Meníngea/diagnóstico por imagem , Tuberculose Meníngea/tratamento farmacológico , Transtornos da Visão/etiologiaRESUMO
To describe a case of familial exudative vitreoretinopathy presenting with unilateral rhegmatogenous retinal detachment in a Malay teenager.