Karczewicz D

Sodium Iodate Selectively Injuries the Posterior Pole of the Retina in a Dose-Dependent Manner: Morphological and Electrophysiological Study

Sequential morphological and functional features of retinal damage in mice exposed to different doses (40 vs. 20xa0mg/kg) of sodium iodate (NaIO3) were analyzed. Retinal morphology, apoptosis (TUNEL assay), and function (electroretinography; ERG) were examined at several time points after NaIO3 administration. The higher dose of NaIO3 caused progressive degeneration of the whole retinal area and total suppression of scotopic and photopic ERG. In contrast, the lower dose induced much less severe degeneration in peripheral part of retina along with a moderate decline of b- and a-wave amplitudes in ERG, corroborating the presence of regions within retina that retain their function. The peak of photoreceptor apoptosis was found on the 3rd day, but the lower dose induced more intense reaction within the central retina than in its peripheral region. In conclusion, these results indicate that peripheral area of the retina reveals better resistance to NaIO3 injury than its central part.

Elevated Plasma Levels of C3a Complement Compound in the Exudative Form of Age-Related Macular Degeneration

Aim: Recent findings suggest that chronic inflammatory processes play a role in the progression of age-related macular degeneration (AMD). Here we asked whether the development of different forms of AMD is connected with the elevation of plasma C3a-desArg concentration. Methods: We recruited 30 subjects with a clinical diagnosis of exudative AMD with newly diagnosed choroidal neovascularization (CNV), 30 subjects with dry AMD and 30 age- and sex-matched volunteers without AMD. The concentration of C3a-desArg complement compound was measured in the subjects’ peripheral blood. We evaluated the association between the level of C3a-desArg and age, sex, smoking, atherosclerosis, and hypertension. Results: We found that the levels of C3a-desArg were significantly elevated in patients with exudative AMD compared to the control group. The concentrations of C3a-desArg in patients with dry AMD were similar to those of controls. Additionally, patients and controls with documented atherosclerosis (AS) displayed significantly higher levels of C3a-desArg compared to subjects without AS. Conclusions: Our results suggest an association between systemic complement activation and the development of CNV. Moreover, we found an association of complement activation with atherosclerosis and confirmed the hypothesis that AMD can be a local manifestation of systemic disease.

Different populations of circulating endothelial cells in patients with age-related macular degeneration: a novel insight into pathogenesis.

PURPOSEnCirculating endothelial cells (CECs) and endothelial progenitor cells (EPCs) may serve as novel markers of endothelial dysfunction. The presence and clinical implications of CECs and the expression of endothelin (ET)-1, one of the most potent vasoconstrictors, have not been evaluated in patients with the neovascular form of age-related macular degeneration (AMD). This study was conducted to determine the different populations of endothelial cells (ECs) in the peripheral blood of AMD patients and to correlate these findings with the expression of ET-1 and the cytokines and growth factors responsible for EC migration and function.nnnMETHODSnPeripheral blood samples were collected from 29 patients with diagnosed neovascular AMD and from 38 healthy control subjects. CD133(-)CD144(+) CECs and CD34(+)CD133(+)CD144(+) EPCs were counted and analyzed by flow cytometry. The intracellular expression of ET-1 in peripheral blood nuclear cells (PBNCs) was studied by using qRT-PCR, Western blot, and immunocytofluorescence assays, and ET-1, IGF-1, VEGF, SDF-1, and HGF plasma concentrations were measured in enzyme-linked immunosorbent assays.nnnRESULTSnIncreased CECs and EPCs were found in the AMD patients compared with the counts in healthy individuals. The expression of intracellular ET-1 was significantly elevated in PBNCs from the AMD patients compared with the control subjects. In addition a significantly higher plasma concentration of IGF-1 was observed, but a lower SDF-1 level in the group of AMD patients.nnnCONCLUSIONSnThese findings suggest that circulating endothelial cells, together with high ET-1 content, may contribute to the development of AMD. Further prospective investigations on the mechanism involved may be relevant to the potential treatment of this disease.

Potential Application of Adult Stem Cells in Retinal Repair—Challenge for Regenerative Medicine

Stem cells (SCs) maintain the balance among somatic cell populations in various tissues and are responsible for organ regeneration. The remarkable progress of regenerative medicine in the last few years indicates promise for the use of SCs in ophthalmic disorder treatment. This review describes the current view on hierarchy in the SC compartment and presents the latest attempts to use adult SCs in the regeneration of the retina. Research performed primarily in animal models gives hope for using similar strategies in humans. However, the search for the optimal source of SCs for cell therapy continues. We briefly discuss various potential sources of adult SCs that could be employed in regenerative medicine, particularly focusing on recently identified, very small embryonic-like SCs (VSEL-SCs). These cells are even present in the bone marrow and adult tissues of older patients and could be harvested from cord blood. We believe that VSEL-SCs, after the establishment of ex vivo expansion and differentiation protocols, could be harnessed for retina regeneration.

Stem Cells are mobilized from the bone marrow into the peripheral circulation in response to retinal pigment epithelium damage--a pathophysiological attempt to induce endogenous regeneration.

Purpose: Stem cell regeneration of damaged tissue has recently been reported in many different organs. Here, we investigated the mobilization of different stem/progenitor cell (SPC) populations into the peripheral blood (PB), their subsequent homing to the injured retina (IR) and contribution to its regeneration in a retinal pigment epithelium (RPE) damage model induced by sodium iodate (NaIO3). Methods: Mobilization of SPCs was evaluated by flow cytometry. SPCs distribution in IR was assessed using bone marrow (BM)-derived GFP+Lin− cells transplanted intravenously into NaIO3-treated C57Bl/6 mice. The quantity of the chemokine SDF-1 in PB and IR was measured by ELISA and qRT-PCR, respectively. Apoptosis (TUNEL assay), cell proliferation (PCNA analysis) as well as functional retinal activity (electroretinogram) were examined at several time points after NaIO3 administration. Results: Mobilization of SPCs along with the highest cell proliferation and massive apoptosis within IR were observed on the third day after NaIO3 administration. Similarly, donor GFP+Lin− cells were detected in the retina as soon as day 4 after NaIO3 injection. Plasma levels of SDF-1 did not differ significantly in mice exposed to NaIO3 compared to healthy controls, however mRNA for SDF-1 was overexpressed locally in IR. Functional retinal recovery was not achieved. Conclusion: Our study provides evidence that BM SPCs egress into PB and home to the injured retina, but are not capable of restoring its function. These results indicate that if the range of retinal destruction is profound, endogenous regeneration is ineffective and may ultimately require adjuvant therapeutic transplantation of specific SPCs subpopulations.

Circulating Stem Cell Populations in Preterm Infants: Implications for the Development of Retinopathy of Prematurity

OBJECTIVEnTo investigate the association among different circulating stem cell (SC) populations, the levels of selected growth factors and chemokines regulating SC migration in the peripheral blood, and the incidence of retinopathy of prematurity (ROP).nnnMETHODSnWe evaluated 88 participants in this study: 29 preterm infants with ROP, 29 preterm infants without ROP, and 30 healthy full-term infants. Peripheral blood samples collected 10 weeks after delivery were analyzed using flow cytometry, immunofluorescence, real-time reverse transcriptase-polymerase chain reaction, and enzyme-linked immunosorbent assay. The following cell populations were analyzed: (1) lin⁻CXCR4(+)CD45⁻ (enriched in very small embryonic-like SCs), (2) lin⁻CXCR4(+)CD45(+) (enriched in hematopoietic SCs), and (3) CD34(+)CD133(+)CD144(+) (early endothelial progenitor cells) [lin indicates lineage]. The concentrations of vascular endothelial growth factor, basic fibroblast growth factor, hepatocyte growth factor, and stromal cell-derived factor 1 were measured in the plasma.nnnRESULTSnThe very small embryonic-like SCs and early endothelial progenitor cells expressing neural and endothelial markers were significantly increased in the preterm infants. The number of early endothelial progenitor cells in the peripheral blood was significantly greater in the preterm infants with ROP than in the preterm infants without ROP. An accompanying increase in the concentrations of vascular endothelial growth factor and hepatocyte growth factor was found in the peripheral blood of the preterm infants with ROP. No significant associations were found between hematopoietic SCs and ROP or prematurity.nnnCONCLUSIONSnThe increased number of early endothelial progenitor cells along with elevated levels of vascular endothelial growth factor and hepatocyte growth factor in preterm infants with ROP suggest that circulating vasculogenic factors may play a role in the development and progression of ROP. The increased number of very small embryonic-like SCs in preterm infants suggests that the development of immature tissues and organs, including the retina, may require a contribution of circulating SCs.

Influence of Ranibizumab on Vascular Endothelial Growth Factor Plasma Level and Endothelial Progenitor Cell Mobilization in Age-Related Macular Degeneration Patients: Safety of Intravitreal Treatment for Vascular Homeostasis

PURPOSEnIntravitreal ranibizumab, which neutralizes vascular endothelial growth factor (VEGF), nowadays constitutes the first-line treatment in neovascular age-related macular degeneration (AMD). However, its potential systemic effect on vascular homeostasis as the consequence of such therapy has not been extensively investigated.nnnMETHODSnPeripheral blood (PB) samples from 12 patients with newly diagnosed neovascular AMD were analyzed before as well as 1 and 4 weeks after intravitreal treatment with ranibizumab. VEGF plasma levels, the number of circulating endothelial progenitor cells (EPCs), and the intracellular expression of hypoxia-inducible factor (HIF) in PB cells were determined by enzyme-linked immunosorbent assay, flow cytometry, and real-time quantitative reverse transcriptase-polymerase chain reaction assays, respectively.nnnRESULTSnNo significant changes within the analyzed parameters were found in the first or fourth weeks after ranibizumab injection compared with the primary, basic values before treatment. Based on our findings, intravitreal ranibizumab does not induce significant systemic effects or vascular impairment.nnnCONCLUSIONSnEvaluation of the VEGF plasma level, the PB EPC concentration, and intracellular HIF expression may be supportive indicators of drug safety for ranibizumab.

Neural stem/progenitor cells circulating in peripheral blood of patients with neovascular form of AMD: a novel view on pathophysiology

BackgroundThe neovascular form of age-related macular degeneration (AMD) manifested with choroidal neovascularization (CNV) is one of the leading causes of rapid and irreversible visual loss. Recent reports suggest that bone marrow-derived stem/progenitor cells (SPCs) play a crucial role in the development and progression of the disease. The purpose of this study was to investigate whether or not undifferentiated non-haematopoietic stem cells, including those capable of differentiating into neural phenotypes, play a role in the pathological state of CNV formation.MethodsPeripheral blood samples were collected from 46 patients diagnosed with CNV and from 46 controls. The CXCR4+Lin-CD45- stem cells were counted and analysed by flow cytometry. Using qRT-PCR and immunocytofluorescence, the expression of early neural and glial cell markers (β-III-tubulin, nestin, and glial fibrillary acidic protein) in the sorted cells was analysed, and correlated with plasma concentrations of stromal cell-derived factor 1 (SDF-1) (enzyme-linked immunosorbent assay), which is a pivotal chemokine that regulates the trafficking of SPCs.ResultsWe found that the number of circulating CXCR4+Lin-CD45- cells did not differ in patients with active CNV as compared to the controls. However, we noticed significant intracellular overexpression of β-III-tubulin in the cells derived from AMD patients. Moreover, we observed significantly lower SDF-1 plasma levels in neovascular AMD patients compared to healthy individuals.ConclusionsOur findings suggest that neural progenitor cells, together with low SDF-1 concentrations, may play a considerable role in the process of AMD progression. Further investigations aimed at the precise elucidation of these issues may help with the future development of effective prevention against, and the treatment of, this disease.

Refractive status and ocular axial length in preterm infants without retinopathy of prematurity with regard to birth weight and gestational age.

Abstract Purpose: To obtain ultrasonographic measurements of ocular axial length (AL) in preterm infants without retinopathy of prematurity (ROP) but with different refractive power in regard to birth weight (BW) and gestational age (GA). Methods: Refraction was measured after cycloplegia (at 6 months of life) in 350 eyes of 180 preterm (non-astigmatic) infants without ROP. Subjects were grouped according to the refractive error: A [above –6.0 dioptres (D)]; B (–3.1 to –6.0 D); C (0 to –3.0 D); D (0.1 to +3.0 D); E (+3.1 to +6.0 D); F (above +6.0 D). The AL measurement was performed by ocular A-scan ultrasound biometry (10 MHz probe). Results: The longest AL was found in group B (20.62 mm) compared to group D and E (19.35, 19.28 mm; P≤0.01) and group F and A (19.63, 19.39 mm; P≤0.05). Only regressive correction for BW was statistically significant. Correlations between AL and BW (Rs=0.23) or GA (Rs=0.17) were found only in group E. Conclusions: AL of myopic eyes was significantly longer. In general, hyperopia was positively correlated with BW, whereas correlation between myopia and BW or GA was not found.

A 43-year-old man with reduced visual acuity and normal fundus: occult macular dystrophy—case report

Purpose Occult macular dystrophy (OMD) is an unusual, inherited macular dystrophy characterized by a slowly progressive decline of visual acuity with normal fundus and fluorescein angiography (FA). The authors present a 43-year-old man who was diagnosed as having OMD because of the results of electrophysiological, psychophysical, optical coherence tomography (OCT) tests. Methods Routine ophthalmological evaluation, FA, visual field tests, electroretinographic examinations (EOG, ERG, PERG and mfERG recordings according to ISCEV standards) and foveal thickness measurements (OCT) were performed. Results Funduscopic examinations, FA, full field ERG as well as PERG results were all normal. In both eyes, the abnormalities were observed in static perimetry (relative central scotomas), mfERG (significant reduction of P1 amplitude in the central retinas) and OCT (significantly thinner foveal thickness). Conclusions A new case with OMD is added to preceding reports. The mfERG and OCT tests are important in detection of OMD patients. It can help in differential diagnosis of amblyopia, optic nerve diseases and non-organic visual disorders.