Noboru Arimura

Repeatability and Reproducibility of Subfoveal Choroidal Thickness in Normal Eyes of Japanese Using Different SD-OCT Devices

PURPOSE To compare subfoveal choroidal thickness (SCT) measurements of three different commercially available spectral-domain optical coherence tomography instruments with healthy eyes of Japanese. METHODS A prospective, cross-sectional study was performed at a single institution. SCT of the right eye of 43 normal subjects was measured using three different SD-OCTs: Heidelberg Spectralis-OCT (Spectralis), Cirrus HD-OCT (Cirrus), and Topcon 3D OCT-1000 Mark II (Topcon). Two separate measurements were performed for the same eye with a maximum by a single examiner. SCT was defined as the distance from the posterior edge of the retinal pigment epithelium to the choroid/sclera junction. After manual segmentation, measurements were made using calipers equipped on each machine by masked raters. Intraclass, interrater, and intermachine agreements were assessed. RESULTS Forty-three subjects (mean age, 30.5 years) were enrolled. Of 43 eyes, the SCT of 39 eyes (90.7%) could be measured using each machine. Intraclass correlation coefficients (95% confidence intervals) were 0.976 (0.954-9.987), 0.958 (0.919-0.978), and 0.939 (0.895-0.971) with Spectralis, Cirrus, and Topcon, respectively. Interrater correlation coefficients (95% confident interval) were 0.944 (0.893 to 0.971), 0.956 (0.831 to 0.983), and 0.924 (0.825 to 0.964) with Spectralis, Cirrus, and Topcon, respectively. The average SCT was 272.6, 272.8, and 269.2 μm with Spectralis, Cirrus, and Topcon, respectively. The intermachine correlation coefficient was significantly high among the machines (P<0.001, Spearman), 0.97 (Spectralis-Cirrus), 0.96 (Cirrus-Topcon), and 0.98 (Topcon-Cirrus). Bland-Altman plot analysis showed no typical trend among the machines. CONCLUSIONS SCT measurements obtained with three different SD-OCTs were highly correlated and could be used interchangeably. (http://upload.umin.ac.jp number, UMIN000005287.).

Vitreous Mediators after Intravitreal Bevacizumab or Triamcinolone Acetonide in Eyes with Proliferative Diabetic Retinopathy

PURPOSE To evaluate vitreous vascular endothelial growth factor (VEGF), stromal cell-derived factor 1alpha (SDF-1alpha), interleukins (ILs), and tumor necrosis factor-alpha (TNF-alpha) after intravitreal bevacizumab or triamcinolone acetonide (TA) in eyes with proliferative diabetic retinopathy (PDR). DESIGN Interventional, consecutive, retrospective, comparative study with a historical control. PARTICIPANTS Forty-seven eyes of 47 patients affected by active PDR were investigated. Bevacizumab (1.25 mg; 19 eyes; bevacizumab group) or TA (4 mg; 10 eyes; TA group) was injected into the vitreous cavity as preoperative adjunctive therapy 7 days before vitrectomy. Eighteen eyes without injection served as controls (control group). METHODS The vitreous samples were obtained at vitrectomy and were analyzed for concentrations of total protein, VEGF, SDF-1alpha, IL-1beta, IL-6, IL-8, IL-10, IL-12p70, and TNF-alpha. MAIN OUTCOME MEASURES Vitreous concentrations of VEGF, SDF-1alpha, ILs, and TNF-alpha were compared among bevacizumab, TA, and control groups. RESULTS Vitreous concentrations of VEGF and SDF-1alpha were lower in bevacizumab and TA groups compared with the control group. The median VEGF level was 0 pg/ml (range, 0-79.2 pg/ml) in the bevacizumab group, 343.5 pg/ml (range, 0-1683.3 pg/ml) in the TA group, and 1202.5 pg/ml (range, 76-4213.9 pg/ml) in the control group. The median SDF-1alpha level was 149.2 pg/ml (range, 0-519.4 pg/ml) in the bevacizumab group, 87.5 pg/ml (range, 0-252.5 pg/ml) in the TA group, and 245.7 pg/ml (range, 0-856.8 pg/ml) in the control group. The differences in both vitreous VEGF and SDF-1alpha concentrations among 3 groups were statistically significant (P<0.001 and P = 0.010, respectively). The eyes with intravitreal bevacizumab demonstrated the lowest vitreous level of VEGF, and the level was statistically significant compared with the eyes with intravitreal TA and control eyes (P<0.001 and P<0.001, respectively). The control eyes had the highest vitreous level of SDF-1alpha, and the level was statistically significant compared with the eyes with intravitreal bevacizumab and TA (P = 0.015 and P = 0.009, respectively). There was no significant difference regarding ILs and TNF-alpha. CONCLUSIONS Intravitreal injection of bevacizumab potentially diminishes not only VEGF but also SDF-1alpha. These findings suggest that intravitreal bevacizumab may influence intraocular mediators beyond VEGF. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Edaravone attenuates cerebral ischemic injury by suppressing aquaporin-4

Aquaporin-4 (AQP4) plays a role in the generation of post-ischemic edema. Pharmacological modulation of AQP4 function may thus provide a novel therapeutic strategy for the treatment of stroke, tumor-associated edema, epilepsy, traumatic brain injury, and other disorders of the central nervous system (CNS) associated with altered brain water balance. Edaravone, a free radical scavenger, is used for the treatment of acute ischemic stroke (AIS) in Japan. In this study, edaravone significantly reduced the infarct area and improved the neurological deficit scores at 24h after reperfusion in a rat transient focal ischemia model. Furthermore, edaravone markedly reduced AQP4 immunoreactivity and protein levels in the cerebral infarct area. In light of observations that edaravone specifically inhibited AQP4 in a rat transient focal ischemia model, we propose that edaravone might reduce cerebral edema through the inhibition of AQP4 expression following cerebral infarction.

Posturing time after macular hole surgery modified by optical coherence tomography images: a pilot study.

PURPOSE To see the early postoperative stage of macular hole (MH) surgery and to distinguish eyes needing prolonged posturing from those that do not use Fourier-domain optical coherence tomography (FD-OCT). DESIGN Interventional case series. METHODS Sixteen eyes of 15 patients with MH underwent the protocol at Kagoshima University Hospital. After the pars plana vitrectomy with 16% SF(6) gas tamponade followed by posturing, the eyes were examined by FD OCT from 3 hours to the day after surgery. After MH closure was confirmed, posturing was stopped. Follow-up was performed for 4 months or longer. The main outcome measures included time and OCT finding of MH closure after surgery. RESULTS On the day after surgery, the macula could be examined by FD-OCT in 13 of 16 eyes; 10 eyes had a closed MH and 3 had an unclosed MH. At day 2, 2 of the 3 eyes with unclosed MHs on day 1 demonstrated a closed MH. Posturing continued for 8 days in 4 eyes whose MH closure was not confirmed. The MH was closed in all eyes within 1 month. FD-OCT showed bridge formation of the neural retina in 9 eyes and simple closure in 3 eyes within 7 days. At 1 month, 12 eyes showed simple closure and 4 eyes showed bridge formation. Among 9 eyes with bridge formation within 7 days, 6 eyes had changed to simple closure at 1 month. CONCLUSIONS FD-OCT enabled confirmation of MH closure the day after surgery even in gas-filled eyes. This imaging method may be a good indicator to determine when to stop posturing for each patient.

B Cell-Derived Vascular Endothelial Growth Factor A Promotes Lymphangiogenesis and High Endothelial Venule Expansion in Lymph Nodes

Vascular endothelial growth factor A (VEGF-A) is a prominent growth factor for both angiogenesis and lymphangiogenesis. Recent studies have shown the importance of VEGF-A in enhancing the growth of lymphatic endothelial cells in lymph nodes (LNs) and the migration of dendritic cells into LNs. VEGF-A is produced in inflamed tissues and/or in draining LNs, where B cells are a possible source of this growth factor. To study the effect of B cell-derived VEGF-A, we created transgenic mice (CD19Cre/hVEGF-Afl) that express human VEGF-A specifically in B cells. We found that the human VEGF-A produced by B cells not only induced lymphangiogenesis in LNs, but also induced the expansion of LNs and the development of high endothelial venules. Contrary to our expectation, we observed a significant decrease in the Ag-specific Ab production postimmunization with OVA and in the proinflammatory cytokine production postinoculation with LPS in these mice. Our findings suggest immunomodulatory effects of VEGF-A: B cell-derived VEGF-A promotes both lymphangiogenesis and angiogenesis within LNs, but then suppresses certain aspects of the ensuing immune responses.

C-reactive protein induces high-mobility group box-1 protein release through activation of p38MAPK in macrophage RAW264.7 cells

BACKGROUND C-reactive protein (CRP) is widely used as a sensitive biomarker for inflammation. Increasing evidence suggests that CRP plays a role in inflammation. High-mobility group box-1 (HMGB1), a primarily nuclear protein, is passively released into the extracellular milieu by necrotic or damaged cells and is actively secreted by monocytes/macrophages. Extracellular HMGB1 as a potent inflammatory mediator has stimulated immense curiosity in the field of inflammation research. However, the molecular dialogue implicated between CRP and HMGB1 in delayed inflammatory processes remains to be explored. METHODS AND RESULTS The levels of HMGB1 in culture supernatants were determined by Western blot analysis and enzyme-linked immunosorbent assay in macrophage RAW264.7 cells. Purified CRP induced the release of HMGB1 in a dose- and time-dependent fashion. Immunofluorescence analysis revealed nuclear translocation of HMGB1 in response to CRP. The binding of CRP to the Fc gamma receptor in RAW264.7 cells was confirmed by fluorescence-activated cell sorter analysis. Pretreatment of cells with IgG-Fc fragment, but not IgG-Fab fragment, efficiently blocked this binding. CRP triggered the activation of p38MAPK and ERK1/2, but not Jun N-terminal kinase. Moreover, both p38MAPK inhibitor SB203580 and small interfering RNA significantly suppressed the release of HMGB1, but not the MEK1/2 inhibitor U-0126. CONCLUSION We demonstrated for the first time that CRP, a prominent risk marker for inflammation including atherosclerosis, could induce the active release of HMGB1 by RAW264.7 cells through Fc gamma receptor/p38MAPK signaling pathways, thus implying that CRP plays a crucial role in the induction, amplification, and prolongation of inflammatory processes, including atherosclerotic lesions.

Intraocular expression and release of high-mobility group box 1 protein in retinal detachment

High-mobility group box 1 (HMGB1) protein is a multifunctional protein, which is mainly present in the nucleus and is released extracellularly by dying cells and/or activated immune cells. Although extracellular HMGB1 is thought to be a typical danger signal of tissue damage and is implicated in diverse diseases, its relevance to ocular diseases is mostly unknown. To determine whether HMGB1 contributes to the pathogenesis of retinal detachment (RD), which involves photoreceptor degeneration, we investigated the expression and release of HMGB1 both in a retinal cell death induced by excessive oxidative stress in vitro and in a rat model of RD-induced photoreceptor degeneration in vivo. In addition, we assessed the vitreous concentrations of HMGB1 and monocyte chemoattractant protein 1 (MCP-1) in human eyes with RD. We also explored the chemotactic activity of recombinant HMGB1 in a human retinal pigment epithelial (RPE) cell line. The results show that the nuclear HMGB1 in the retinal cell is augmented by death stress and upregulation appears to be required for cell survival, whereas extracellular release of HMGB1 is evident not only in retinal cell death in vitro but also in the rat model of RD in vivo. Furthermore, the vitreous level of HMGB1 is significantly increased and is correlated with that of MCP-1 in human eyes with RD. Recombinant HMGB1 induced RPE cell migration through an extracellular signal-regulated kinase-dependent mechanism in vitro. Our findings suggest that HMGB1 is a crucial nuclear protein and is released as a danger signal of retinal tissue damage. Extracellular HMGB1 might be an important mediator in RD, potentially acting as a chemotactic factor for RPE cell migration that would lead to an ocular pathological wound-healing response.

The Free Radical Scavenger Edaravone Rescues Rats from Cerebral Infarction by Attenuating the Release of High-Mobility Group Box-1 in Neuronal Cells

Edaravone, a potent free radical scavenger, is clinically used for the treatment of cerebral infarction in Japan. Here, we examined the effects of edaravone on the dynamics of high-mobility group box-1 (HMGB1), which is a key mediator of ischemic-induced brain damage, during a 48-h postischemia/reperfusion period in rats and in oxygen-glucose-deprived (OGD) PC12 cells. HMGB1 immunoreactivity was observed in both the cytoplasm and the periphery of cells in the cerebral infarction area 2 h after reperfusion. Intravenous administration of 3 and 6 mg/kg edaravone significantly inhibited nuclear translocation and HMGB1 release in the penumbra area and caused a 26.5 ± 10.4 and 43.8 ± 0.5% reduction, respectively, of the total infarct area at 24 h after reperfusion. Moreover, edaravone also decreased plasma HMGB1 levels. In vitro, edaravone dose-dependently (1–10 μM) suppressed OGD- and H2O2-induced HMGB1 release in PC12 cells. Furthermore, edaravone (3–30 μM) blocked HMGB1-triggered apoptosis in PC12 cells. Our findings suggest a novel neuroprotective mechanism for edaravone that abrogates the release of HMGB1.

Minocycline attenuates both OGD-induced HMGB1 release and HMGB1-induced cell death in ischemic neuronal injury in PC12 cells.

High mobility group box-1 (HMGB1), a non-histone DNA-binding protein, is massively released into the extracellular space from neuronal cells after ischemic insult and exacerbates brain tissue damage in rats. Minocycline is a semisynthetic second-generation tetracycline antibiotic which has recently been shown to be a promising neuroprotective agent. In this study, we found that minocycline inhibited HMGB1 release in oxygen-glucose deprivation (OGD)-treated PC12 cells and triggered the activation of p38mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinases (ERK1/2). The ERK kinase (MEK)1/2 inhibitor U-0126 and p38MAPK inhibitor SB203580 blocked HMGB1 release in response to OGD. Furthermore, HMGB1 triggered cell death in a dose-dependent fashion. Minocycline significantly rescued HMGB1-induced cell death in a dose-dependent manner. In light of recent observations as well as the good safety profile of minocycline in humans, we propose that minocycline might play a potent neuroprotective role through the inhibition of HMGB1-induced neuronal cell death in cerebral infarction.

Stromal Cell-Derived Factor-1 Is Essential for Photoreceptor Cell Protection in Retinal Detachment

Stromal cell-derived factor-1 (SDF-1) causes chemotaxis of CXCR4-expressing bone marrow-derived cells. SDF-1 is involved in the pathogenesis of various vascular diseases, including those of the eye. However, the role of SDF-1 in neuronal diseases is not completely understood. Here, we show higher SDF-1 levels in the vitreous humor of patients with retinal detachment (RD) compared with normal patients. SDF-1 correlated positively with the duration as well as the extent of RD. Furthermore, SDF-1 correlated significantly with levels of interleukin-6 and interleukin-8, but not with vascular endothelial growth factor. Western blot analysis results showed significant SDF-1 up-regulation in detached rat retinas compared with normal animals. Immunohistochemistry data showed that SDF-1 was co-localized with the glial cells of the detached retina. SDF-1 blockade with a neutralizing antibody increased photoreceptor cell loss and macrophage accumulation in the subretinal space. The retinal precursor cell line R28 expressed CXCR4. SDF-1 rescued serum starvation-induced apoptosis in R28 cells and enhanced their ability to participate in wound closure in a scratch assay. Our results indicate a surprising, protective role for SDF-1 in RD. This effect may be mediated directly or indirectly through other cell types.