Anatomical Changes in the Anterior Chamber Volume After Descemet Membrane Endothelial Keratoplasty.

PURPOSE: To evaluate changes in the anterior chamber of eyes that have undergone Descemet membrane endothelial keratoplasty (DMEK) and to identify factors that affect these changes. METHODS: This retrospective study included 25 pseudophakic eyes of 25 patients who underwent DMEK. We determined the preoperative and postoperative values of the best spectacle-corrected visual acuity, spherical equivalent (SE), anterior chamber volume (ACV), anterior chamber depth (ACD), central corneal thickness (CCT), and scleral spur angle (SSA) evaluated using anterior segment optical coherence tomography and iris damage score and iris posterior synechiae score. We defined ∆ as the average change rate from the preoperative to postoperative value for each factor at 1 month (SE at 6-12 months) postoperatively. We also analyzed correlations between ∆ACV, ∆SE, and other preexisting factors. RESULTS: Compared with the preoperative ACV value (128 ± 28 mm3), the postoperative value significantly increased to 155 ± 21 mm3 (P < 0.001); ∆SE was +1.01 ± 1.09 diopters. ∆ACV was negatively correlated with preoperative ACD (R = 0.643, P < 0.001) and SSA (R = 0.555, P = 0.001) and positively correlated with ∆ACD (R = 0.799, P < 0.001) and ∆SSA (R = 0.608, P < 0.001). ∆CCT, iris damage score, and iris posterior synechiae score were not significantly correlated with ∆ACV. ∆SE was positively correlated with ∆ACV, ∆ACD, and ∆SSA (R = 0.680, 0.455, and 0.478; P < 0.001, <0.05, and <0.05, respectively). CONCLUSIONS: An increase in the ACV and hyperopic change was noted after successful DMEK, especially in eyes with narrow-angled shallow anterior chambers.

Endogenous reactive oxygen species cause astrocyte defects and neuronal dysfunctions in the hippocampus: a new model for aging brain.

The etiology of astrocyte dysfunction is not well understood even though neuronal defects have been extensively studied in a variety of neuronal degenerative diseases. Astrocyte defects could be triggered by the oxidative stress that occurs during physiological aging. Here, we provide evidence that intracellular or mitochondrial reactive oxygen species (ROS) at physiological levels can cause hippocampal (neuronal) dysfunctions. Specifically, we demonstrate that astrocyte defects occur in the hippocampal area of middle-aged Tet-mev-1 mice with the SDHCV69E mutation. These mice are characterized by chronic oxidative stress. Even though both young adult and middle-aged Tet-mev-1 mice overproduced MitoSOX Red-detectable mitochondrial ROS compared to age-matched wild-type C57BL/6J mice, only young adult Tet-mev-1 mice upregulated manganese and copper/zinc superoxide dismutase (Mn- and Cu/Zn-SODs) activities to eliminate the MitoSOX Red-detectable mitochondrial ROS. In contrast, middle-aged Tet-mev-1 mice accumulated both MitoSOX Red-detectable mitochondrial ROS and CM-H2 DCFDA-detectable intracellular ROS. These ROS levels appeared to be in the physiological range as shown by normal thiol and glutathione disulfide/glutathione concentrations in both young adult and middle-aged Tet-mev-1 mice relative to age-matched wild-type C57BL/6J mice. Furthermore, only middle-aged Tet-mev-1 mice showed JNK/SAPK activation and Ca2+ overload, particularly in astrocytes. This led to decreasing levels of glial fibrillary acidic protein and S100ß in the hippocampal area. Significantly, there were no pathological features such as apoptosis, amyloidosis, and lactic acidosis in neurons and astrocytes. Our findings suggest that the age-dependent physiologically relevant chronic oxidative stress caused astrocyte defects in mice with impaired mitochondrial electron transport chain functionality.

Genetically induced oxidative stress in mice causes thrombocytosis, splenomegaly and placental angiodysplasia that leads to recurrent abortion.

Historical data in the 1950s suggests that 7%, 11%, 33%, and 87% of couples were infertile by ages 30, 35, 40 and 45, respectively. Up to 22.3% of infertile couples have unexplained infertility. Oxidative stress is associated with male and female infertility. However, there is insufficient evidence relating to the influence of oxidative stress on the maintenance of a viable pregnancy, including pregnancy complications and fetal development. Recently, we have established Tet-mev-1 conditional transgenic mice, which can express the doxycycline-induced mutant SDHC(V69E) transgene and experience mitochondrial respiratory chain dysfunction leading to intracellular oxidative stress. In this report, we demonstrate that this kind of abnormal mitochondrial respiratory chain-induced chronic oxidative stress affects fertility, pregnancy and delivery rates as well as causes recurrent abortions, occasionally resulting in maternal death. Despite this, spermatogenesis and early embryogenesis are completely normal, indicating the mutation's effects to be rather subtle. Female Tet-mev-1 mice exhibit thrombocytosis and splenomegaly in both non-pregnant and pregnant mice as well as placental angiodysplasia with reduced Flt-1 protein leading to hypoxic conditions, which could contribute to placental inflammation and fetal abnormal angiogenesis. Collectively these data strongly suggest that chronic oxidative stress caused by mitochondrial mutations provokes spontaneous abortions and recurrent miscarriage resulting in age-related female infertility.

Topical dorzolamide for macular edema in the early phase after vitrectomy and epiretinal membrane removal.

BACKGROUND: The purpose of this study was to evaluate prospectively the efficacy of a topical carbonic anhydrase inhibitor in macular edema after vitrectomy. METHODS: Forty patients were included, all of whom had undergone vitrectomy combined with phacoemulsification and intraocular lens implantation for epiretinal membrane. Twenty eyes from 40 patients received topical 2% dorzolamide three times a day. The patients were followed up for at least 3 months. In this study, we evaluated the effect of dorzolamide on visual acuity, intraocular pressure, central macular thickness, and aqueous flare. RESULTS: Mean logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity preoperatively and 2 weeks, 1 month, and 3 months after surgery was 0.48 ± 0.23, 0.60 ± 0.16, 0.40 ± 0.29, and 0.24 ± 0.32, respectively, in the treatment group, and 0.40 ± 0.09, 0.44 ± 0.12, 0.32 ± 0.10, and 0.16 ± 0.09, respectively, in the control group. No statistically significant difference was observed between the two groups. Mean central macular thickness preoperatively and at 2 weeks and 3 months after surgery was 572.6, 427.2, and 333.4 µm, respectively, in the treatment group, and 571.4, 485.2, and 388.4 µm, respectively, in the control group. Mean aqueous flare preoperatively, and 1 month and 3 months after surgery was 8.6, 34.2, and 23.5 photon counts per millisecond (pc/ms), respectively, in the treatment group, and 9.7, 24.7, and 23.4 pc/ms, respectively, in the control group. No statistically significant differences were observed between data from the two groups. However, statistically significant (P < 0.05) differences in mean central macular thickness at 1 month and mean aqueous flare at 2 weeks after surgery were found between the treatment group (358.8 µm, 36.8 pc/ms) and the control group (467.8 µm, 64.0 pc/ms). Differences in mean intraocular pressure preoperatively and at 2 weeks, 1 month, and 3 months after surgery were not statistically significant between the two groups. Intraocular pressure never exceeded 21 mmHg. CONCLUSION: Topical dorzolamide significantly reduced mean central macular thickness at 1 month and mean aqueous flare at 2 weeks after surgery for epiretinal membrane compared with controls. Although further investigation of more cases and longer follow-up are needed, this study suggests that topical dorzolamide can be efficacious in reducing macular edema in the early phase after vitrectomy via its anti-inflammatory effect.

Model animals for the study of oxidative stress from complex II.

Mitochondria play a role of energy production and produce intracellular reactive oxygen species (ROS), especially superoxide anion (O2(-)) as a byproduct of energy metabolism at the same time. O2(-) is converted from oxygen and is overproduced by excessive electron leakage from the mitochondrial respiratory chain. It is well known that mitochondrial complexes I and III in the electron transport system are the major endogenous ROS sources. We have previously demonstrated that mutations in complex II can result in excessive ROS (specifically in SDHC: G71E in Caenorhabditis elegans, I71E in Drosophila and V69E in mouse). Moreover, this results in premature death in C. elegans and Drosophila as well as tumorigenesis in mouse embryonic fibroblast cells. In humans, it has been reported that mutations in SDHB, SDHC or SDHD, which are the subunits of mitochondrial complex II, often result in inherited head and neck paragangliomas (PGLs). Recently, we established Tet-mev-1 conditional transgenic mice using our uniquely developed Tet-On/Off system, which can induce the mutated SDHC gene to be equally and competitively expressed compared to the endogenous wild-type SDHC gene. These mice experienced mitochondrial respiratory chain dysfunction that resulted in oxidative stress. The mitochondrial oxidative stress caused excessive apoptosis in several tissues leading to low-birth-weight infants and growth retardation during neonatal developmental phase in Tet-mev-1 mice. Tet-mev-1 mice also displayed precocious age-dependent corneal physiological changes, delayed corneal epithelialization, decreased corneal endothelial cells, thickened Descemet's membrane and thinning of parenchyma with corneal pathological dysfunctions such as keratitis, Fuchs' corneal dystrophy (FCD) and probably keratoconus after the normal development and growth phase. Here, we review the relationships between mitochondrial oxidative stress and phenomena in mev-1 animal models with mitochondrial complex II SDHC mutations. This article is part of a Special Issue entitled: Respiratory complex II: Role in cellular physiology and disease.

Oxidative stress induced inflammation initiates functional decline of tear production.

Oxidative damage and inflammation are proposed to be involved in an age-related functional decline of exocrine glands. However, the molecular mechanism of how oxidative stress affects the secretory function of exocrine glands is unclear. We developed a novel mev-1 conditional transgenic mouse model (Tet-mev-1) using a modified tetracycline system (Tet-On/Off system). This mouse model demonstrated decreased tear production with morphological changes including leukocytic infiltration and fibrosis. We found that the mev-1 gene encodes Cyt-1, which is the cytochrome b(560) large subunit of succinate-ubiquinone oxidoreductase in complex II of mitochondria (homologous to succinate dehydrogenase C subunit (SDHC) in humans). The mev-1 gene induced excessive oxidative stress associated with ocular surface epithelial damage and a decrease in protein and aqueous secretory function. This new model provides evidence that mitochondrial oxidative damage in the lacrimal gland induces lacrimal dysfunction resulting in dry eye disease. Tear volume in Tet-mev-1 mice was lower than in wild type mice and histopathological analyses showed the hallmarks of lacrimal gland inflammation by intense mononuclear leukocytic infiltration and fibrosis in the lacrimal gland of Tet-mev-1 mice. These findings strongly suggest that oxidative stress can be a causative factor for the development of dry eye disease.

Expression of PCNA, ICAM-1, and vimentin in lens epithelial cells of cataract patients with and without type 2 diabetes.

OBJECTIVE: In order to explore the pathological feature in the progression of cataract with type 2 diabetes, we compared the expression of proliferating cell nuclear antigen (PCNA), intercellular adhesion molecule-1 (ICAM-1), and vimentin in lens epithelial cells (LECs) of cataract patients with and without type 2 diabetes. METHODS: The indirect immunoperoxidase technique was performed on anterior capsules obtained from 25 patients with type 2 diabetes (DM group) and 25 patients without diabetes (control group). Immunohistochemical difference in the expression of PCNA, ICAM-1, and vimentin in LECs between the 2 groups was investigated. RESULTS: PCNA expression was decreased (P=0.036) but ICAM-1 expression was significantly increased (P<0.0001) in the DM group as compared with that in the control group. No difference was noted in the expression of vimentin between the 2 groups (P=0.264). CONCLUSIONS: Decreased proliferation of LECs and increased expression of ICAM-1 in LECs might play an important role in the progression of cataract with type 2 diabetes.

Mitochondrial superoxide anion overproduction in Tet-mev-1 transgenic mice accelerates age-dependent corneal cell dysfunctions.

PURPOSE: The Tet-mev-1 mouse expressing a mitochondrial complex-II mutated SDHC(V69E) gene controlled by a tetracycline (Tet)-On/Off system can overproduce O(2)(·-) and is a versatile whole-animal model for studying mitochondrial oxidative stress. Here we report a series of age-dependent variations in corneal epithelium, endothelium, and parenchymal cells of the Tet-mev-1 mice relative to wild-type C57BL/6j mice. METHODS: Measurements of (1) mitochondrial electron transport enzyme activities; (2) O(2)(·-) production; (3) carbonylated protein, and 8-hydroxydeoxyguanosine (8-OHdG) levels as markers of oxidative stress; (4) pathologic analyses under optical and electron microscopy; (5) hematoxylin-eosin or toluidine-blue staining; and (6) immunohistochemistry with an anti-ß-catenin antibody were performed in the eye, especially the cornea. RESULTS: Complex II-III activity was decreased by electron leakage between complex II and CoQ. This resulted in increased age-dependent intracellular oxidative stress in the eye of Tet-mev-1 mice. Corneal epithelialization was delayed in Tet-mev-1 mice after 20% ethanol treatment, as the number of cells and mitotic cells decreased in the corneal epithelium of Tet-mev-1 mice compared with that of wild type. The age-dependent decrease in cell number accelerated in the corneal endothelium cells. Moreover, it was suggested that the corneal thickness was decreased by thinning of parenchymal cells with age in Tet-mev-1 mice. CONCLUSIONS: These results suggest that mitochondrial oxidative stress with electron transport chain dysfunction can influence pathogenesis and progression of age-related corneal diseases, as well as generalized corneal aging acceleration.

A case of recurrence of congenital ocular toxoplasmosis with frosted branch angiitis (ocular toxoplasmosis with frosted branch angiitis).

PURPOSE: To describe a case of recurrence of congenital ocular toxoplasmosis with frosted branch angiitis. CASE REPORT: A 24-year-old woman presented with hyperemia in her right eye. Medical history included epilepsy at age 14 and mild mental retardation. Iridocyclitis and vitreous opacity were observed in the right eye, and furthermore widespread retinal vessel sheathing due to frosted branch angiitis was seen. Acyclovir was initiated for acute retinal necrosis with frosted branch angiitis. One week later, serologic tests showed elevated toxoplasma antibody level and toxoplasma antibody IgG level, and a white retinal exudative lesion with unclear margins was noted. Therefore, acetylspiramycin and prednisolone were initiated for a recurrence of congenital ocular toxoplasmosis. After treatment, inflammation subsided, the exudative lesion shrank, and the frosted branch angiitis improved. CONCLUSION: We encountered a case of ocular toxoplasmosis due to recurrence of congenital toxoplasmosis with frosted branch angiitis. The clinical symptoms of ocular toxoplasmosis can be varied and the diagnosis should be kept in mind.

The role of mitochondrial superoxide anion (O2(-)) on physiological aging in C57BL/6J mice.

Much attention has been focused on the mitochondrial superoxide anion (O2(-)), which is also a critical free radial produced by ionizing radiation. The specific role of the mitochondrial O2(-) on physiological aging in mammals is still unclear despite wide-spread evidence that oxidative stress is involved in aging and age-related diseases. The major endogenous source of O2(-) is generated as a byproduct of energy metabolism from mitochondria. In order to better understand how O2(-)relates to metazoan aging, we have comprehensively examined age-related changes in the levels of oxidative damage, mitochondrial O2(-) production, mitochondrial antioxidant enzyme activity and apoptosis induction in key organs of an inbred mouse strain (C57BL/6J). Oxidative damage accumulated and excess apoptosis occurred in the brain, oculus and kidney with aging, but comparatively little occurred in the heart and muscle. These rates are correlated with O2(-) levels. Mitochondrial O2(-) production levels increased with aging in the brain, oculus and kidney, and did not significantly increased in the heart and muscle. In contrast to O2(-) production, mitochondrial SOD activities increased in heart and muscle, and remained unchanged in the brain, oculus and kidney with aging. These results suggest that O2(-) production has high organ specificity, and oxidative damage by O2(-) from mitochondria mediated apoptosis can lead to organ atrophy and physiological dysfunction. In addition, O2(-) from mitochondria plays a core role in physiological aging.