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Tight glycemic control (TGC), the cornerstone of diabetic management, reduces the incidence and progression of diabetic microvascular disease. However, TGC can also lead to transient episodes of hypoglycemia, which have been associated with adverse outcomes in patients with diabetes. Here, we demonstrate that low glucose levels result in hypoxia-inducible factor (HIF)-1-dependent expression of the glucose transporter, Glut1, in retinal cells. Enhanced nuclear accumulation of HIF-1α was independent of its canonical post-translational stabilization but instead dependent on stimulation of its translation and nuclear localization. In the presence of hypoxia, this physiologic response to low glucose resulted in a marked increase in the secretion of the HIF-dependent vasoactive mediators that promote diabetic retinopathy. Our results provide a molecular explanation for how early glucose control, as well as glycemic variability (i.e., oscillating serum glucose levels), contributes to diabetic eye disease. These observations have important implications for optimizing glucose management in patients with diabetes. [Display omitted] • Diabetic patients experience brief episodes of low glucose (hypoglycemia) each day • In retinal glial cells, hypoglycemia promotes the HIF-dependent expression of GLUT1 • Hypoglycemia increases expression of HIF-dependent angiogenic mediators • This physiologic response causes paradoxical worsening of diabetic retinopathy Guo et al. show that transient episodes of hypoglycemia enhance the nuclear accumulation of HIF-1α, resulting in increased expression of GLUT1 in retinal glial cells. In the presence of hypoxia, this physiologic response results in a pathologic increase in the secretion of HIF-dependent angiogenic mediators that worsen diabetic eye disease. [ABSTRACT FROM AUTHOR]

Abstract: It has been nearly a century since Jules Gonin performed the first intervention for rhegmatogenous retinal detachment, trans-scleral cautery, achieving successful outcomes in close to 50% of his cases. With the introduction of alternative surgical approaches in the last half-century, including Charles Schepens'' scleral buckle technique and Robert Machemer''s pars plana vitrectomy, the surgical success rates have risen to close to 90%. Nonetheless, despite dramatic progress in the success of reattachment surgeries, reasonable disagreement exists as to which approach (or combination of approaches) is the best form of surgical intervention for patients with rhegmatogenous retinal detachments. In this review, the authors summarize the current knowledge of retinal detachment, and examine emerging results from the first large scale, prospective, randomized, controlled clinical trials addressing the efficacy of these surgical approaches for retinal detachment, with the hope of identifying the most appropriate (evidence-based) therapeutic intervention for the treatment of rhegmatogenous retinal detachment. [Copyright &y& Elsevier]

Summary: The Kaposi''s sarcoma-associated herpesvirus (KSHV), the infectious causative agent of Kaposi''s sarcoma (KS), encodes a G protein-coupled receptor (vGPCR) implicated in the initiation of KS. Here we demonstrate that Kaposi''s sarcomagenesis involves stimulation of tuberin (TSC2) phosphorylation by vGPCR, promoting the activation of mTOR through both direct and paracrine mechanisms. Pharmacologic inhibition of mTOR with rapamycin prevented vGPCR sarcomagenesis, while overactivation of this pathway was sufficient to render endothelial cells oncogenic. Moreover, mice haploinsufficient for TSC2 are predisposed to vascular sarcomas remarkably similar to KS. Collectively, these results implicate mTOR in KS initiation and suggest that the sarcomagenic potential of KSHV may be a direct consequence of the profound sensitivity of endothelial cells to vGPCR dysregulation of the TSC2/mTOR pathway. [Copyright &y& Elsevier]

The Kaposi''s sarcoma herpesvirus (KSHV) has been identified as the etiologic agent of Kaposi''s sarcoma (KS), but initial events leading to KS development remain unclear. Characterization of the KSHV genome reveals the presence of numerous potential oncogenes. To address their contribution to the initiation of the endothelial cell-derived KS tumor, we developed a novel transgenic mouse that enabled endothelial cell-specific infection in vivo using virus expressing candidate KSHV oncogenes. Here we show that transduction of one gene, vGPCR, was sufficient to induce angioproliferative tumors that strikingly resembled human KS. Endothelial cells expressing vGPCR were further able to promote tumor formation by cells expressing KSHV latent genes, suggestive of a cooperative role among viral genes in the promotion of Kaposi''s sarcomagenesis. [Copyright &y& Elsevier]

The proto-oncogene c-Src has been implicated in the development and progression of a number of human cancers including those of colon and breast. Accumulating evidence indicates that activated alleles of Src may induce cell transformation through Ras-ERK-dependent and -independent pathways. Here we show that Rac1 activity is strongly elevated in Src-transformed cells and that this small G protein is a critical component of the pathway connecting oncogenic Src with cell transformation. We further show that Vav2 and the ubiquitously expressed Rac1 guanine nucleotide exchange factor Tiam1 are phosphorylated in tyrosine residues in cells transfected with active and oncogenic Src. Moreover, phosphorylation of Tiam1 in cells treated with pervanadate, a potent inhibitor of tyrosine phosphatases, was partially inhibited by the Src inhibitor SU6656. Using truncated mutants of Tiam1, we demonstrate that multiple sites can be tyrosine-phosphorylated by Src. Furthermore, Tiam1 cooperated with Src to induce activation of Rac1 in vivo and the formation of membrane ruffles. Similarly, activation of JNK and the c-jun promoter by Src were also potently increased by Tiam1. Together, these results suggest that Vav2 and Tiam1 may act as downstream effectors of Src, thereby regulating Rac1-dependent pathways that participate in Src-induced cell transformation. [ABSTRACT FROM AUTHOR]

The molecular mechanisms whereby angiopoietin-like 4 (ANGPTL4), a pluripotent protein implicated in cancer development, contributes to head and neck squamous cell carcinoma (HNSCC) growth and dissemination are unclear. We investigated ANGPTL4 expression in human normal oral keratinocytes (NOKs), dysplastic oral keratinocytes (DOKs), oral leukoplakia cells (LEUK1), and HNSCC cell lines, as well as in tissue biopsies from patients with oral dysplasia, and primary and metastatic HNSCC. We further examined the contribution of ANGPTL4 cancer progression in an HNSCC orthotopic floor-of mouth tumor model and the signaling pathways linking ANGPTL4 to cancer cell migration. ANGPTL4 expression was upregulated in premalignant DOKs and HNSCC cell lines compared to NOKs and was increased in tissue biopsies from patients with oral dysplasia, as well as in primary and metastatic HNSCC. We also observed that downregulation of ANGPTL4 expression inhibited primary and metastatic cancer growth in an HNSCC orthotopic tumor model. Interestingly, ANGPTL4 binding to the neuropilin1 (NRP1) receptor led to phosphorylation of the focal adhesion protein, paxillin (PXN), and tumor cell migration; this was dependent on the tyrosine kinase ABL1. Treatment with the ABL1 inhibitor, dasatinib and small interfering RNA silencing of NRP1 or ABL1 expression blocked PXN phosphorylation and tumor cell migration. Our findings suggest an early, sustained, and angiogenesis-independent autocrine role for ANGPTL4 in HNSCC progression and expose ANGPTL4/NRP1/ABL1/PXN as an early molecular marker and vulnerable target for the prevention of HNSCC growth and metastasis. • ANGPTL4 is overexpressed in early and late stages of head and neck carcinogenesis. • ANGPTL4 is important in both HNSCC growth and metastasis in vivo. • ANGPTL4 regulates cell migration through an NRP1-dependent pathway. • ANGPTL4/NRP1/ABL1/PXN is a molecular marker in HNSCC development. [ABSTRACT FROM AUTHOR]

Purpose: To correlate aqueous vasoactive protein changes with macular edema after dexamethasone implant in retinal vein occlusion (RVO). Design: Prospective, interventional case series. Methods: Twenty-three central RVO (CRVO) and 17 branch RVO (BRVO) subjects with edema despite prior anti-vascular endothelial growth factor (VEGF) treatment had aqueous taps at baseline and 4 and 16 weeks after dexamethasone implant. Best-corrected visual acuity (BCVA) and center subfield thickness were measured every 4 weeks. Aqueous vasoactive protein levels were measured by protein array or enzyme-linked immunosorbent assay. Results: Thirty-two vasoactive proteins were detected in aqueous in untreated eyes with macular edema due to RVO. Reduction in excess foveal thickness after dexamethasone implant correlated with reduction in persephin and pentraxin 3 (Pearson correlation coefficients = 0.682 and 0.638, P = .014 and P = .003). Other protein changes differed among RVO patients as edema decreased, but =50% of patients showed reductions in hepatocyte growth factor, endocrine gland VEGF, insulin-like growth factor binding proteins, or endostatin by =30%. Enzyme-linked immunosorbent assay in 18 eyes (12 CRVO, 6 BRVO) showed baseline levels of hepatocyte growth factor and VEGF of 168.2 ± 20.1 pg/mL and 78.7 ± 10.0 pg/mL, and each was reduced in 12 eyes after dexamethasone implant. Conclusions: Dexamethasone implants reduce several pro-permeability proteins providing a multitargeted approach in RVO. No single protein in addition to VEGF can be implicated as a contributor in all patients. Candidates for contribution to chronic edema in subgroups of patients that deserve further study include persephin, hepatocyte growth factor, and endocrine gland VEGF. [ABSTRACT FROM AUTHOR]

Purpose To determine whether scatter and grid laser photocoagulation (laser) adds benefit to ranibizumab injections in patients with macular edema from retinal vein occlusion (RVO) and to compare 0.5-mg with 2.0-mg ranibizumab. Design Randomized, double-masked, controlled clinical trial. Participants Thirty-nine patients with central RVO (CRVO) and 42 with branch RVO (BRVO). Methods Subjects were randomized to 0.5 mg or 2.0 mg ranibizumab every 4 weeks for 24 weeks and re-randomized to pro re nata ranibizumab plus laser or ranibizumab alone. Main Outcome Measures Mean change from baseline best-corrected visual acuity (BCVA) at week 24 for BCVA at weeks 48, 96, and 144 for second randomization. Results Mean improvement from baseline BCVA at week 24 was 15.5 and 15.8 letters in the 0.5-mg and 2.0-mg CRVO groups, and 12.1 and 14.6 letters in the 0.5-mg and 2.0-mg BRVO groups. For CRVO, but not BRVO, there was significantly greater reduction from baseline mean central subfield thickness (CST) in the 2.0-mg versus 0.5-mg group (396.1 vs. 253.5 μm; P = 0.03). For the second randomization in CRVO patients, there was no significant difference from week 24 BCVA in the ranibizumab plus laser versus the ranibizumab only groups at week 48 (−3.3 vs. 0.0 letters), week 96 (+0.69 vs. −1.6 letters), or week 144 (+0.4 vs. −6.7 letters), and a significant increase from week 24 mean CST at week 48 (+94.7 vs. +15.2 μm; P = 0.05) but not weeks 96 or 144. For BRVO, there was a significant reduction from week 24 mean BCVA in ranibizumab plus laser versus ranibizumab at week 48 (−7.5 vs. +2.8; P < 0.01) and week 96 (−2.0 vs. +4.8; P < 0.03), but not week 144, and there were no differences in mean CST change from week 24 at weeks 48, 96, or 144. Laser failed to increase edema resolution or to reduce the ranibizumab injections between weeks 24 and 144. Conclusions In patients with macular edema resulting from RVO, there was no short-term clinically significant benefit from monthly injections of 2.0-mg versus 0.5-mg ranibizumab injections and no long-term benefit in BCVA, resolution of edema, or number of ranibizumab injections obtained by addition of laser treatment to ranibizumab. [ABSTRACT FROM AUTHOR]

PURPOSE: To determine the incidence and progression of macular atrophy in patients with neovascular agerelated macular degeneration (AMD) treated with vascular endothelial growth factor (VEGF) antagonists. DESIGN: Retrospective interventional case series. METHODS: All patients with neovascular AMD treated by the same physician during a 12-month period of ascertainment had all images from their entire follow-up period evaluated, and areas of retina that developed atrophy were compared to the same areas prior to the onset of anti- VEGF treatment. Longitudinal measurements of retinal atrophy were made. RESULTS: In 39 patients, 52 eyes with neovascular AMD were identified. We excluded 5 eyes from analysis (4 had retinal pigment epithelium tears, and 1 had a laser scar). Fundus photographs of the remaining eyes showed that 18/47 eyes (38%) contained hypopigmented areas suggestive of atrophy within the macula at some time during follow-up. Spectral-domain optical coherence tomography confirmed that these areas had loss of retinal pigmented epithelium and ellipsoids zones, with or without subretinal material suggestive of subretinal fibrosis. Comparison of fundus photographs with fluorescein angiograms showed that in 13/18 eyes (72%), atrophy developed in areas previously occupied by choroidal neovascularization, and the other 5 eyes had atrophy prior to the onset of anti-VEGF treatment. The mean (±standard deviation) rate of increase in pure atrophic areas (no subretinal material) was 0.7 ± 0.8 mm2 per year, with a range of 0.01-2.6 mm²/year. CONCLUSION: Treatment of neovascular AMD with a VEGF-neutralizing protein can result in regression of choroidal neovascularization, which is sometimes associated with atrophy of overlying retina. [ABSTRACT FROM AUTHOR]

Summary: Mutually exclusive activating mutations in the GNAQ and GNA11 oncogenes, encoding heterotrimeric Gαq family members, have been identified in ∼83% and ∼6% of uveal and skin melanomas, respectively. However, the molecular events underlying these GNAQ-driven malignancies are not yet defined, thus limiting the ability to develop cancer-targeted therapies. Here, we focused on the transcriptional coactivator YAP, a critical component of the Hippo signaling pathway that controls organ size. We found that Gαq stimulates YAP through a Trio-Rho/Rac signaling circuitry promoting actin polymerization, independently of phospholipase Cβ and the canonical Hippo pathway. Furthermore, we show that Gαq promotes the YAP-dependent growth of uveal melanoma cells, thereby identifying YAP as a suitable therapeutic target in uveal melanoma, a GNAQ/GNA11-initiated human malignancy. [ABSTRACT FROM AUTHOR]

PURPOSE: To determine the percentage of ranibizumab-treated patients with retinal vein occlusion (RVO) who had resolution of edema for at least 6 months after the last injection, along with factors and outcomes that correlate with resolution. DESIGN: Post hoc analysis of open-label clinical trial. METHODS: Twenty patients with branch RVO (BRVO) and 20 with central RVO (CRVO) received ranibizumab monthly for 3 months and as needed for recurrent/persistent macular edema, no more frequently than every 2 months. Patients still requiring injections after month 40 received scatter and grid laser photocoagulation to try to reduce the need for injections. Main outcome measures included the percentage of patients who had resolution of edema, change in best-corrected visual acuity (BCVA) from baseline, and change in area of retinal nonperfusion in central subfields. RESULTS: Nine patients with BRVO (45%) had edema resolution from injections alone after a mean of 20.2 months, 4 resolved after addition of laser, 4 were unresolved through 72 months, and 3 exited prior to resolution. Five patients with CRVO (25%) resolved from injections alone after a mean of 14.0 months, 8 remained unresolved through 72 months despite addition of laser, and 7 exited prior to resolution. For BRVO or CRVO, there was a negative correlation between posterior retinal nonperfusion area and BCVA at months 18, 24, and 36 (P<.05). CONCLUSIONS: In patients with RVO, infrequent ranibizumab injections to control edema may not be sufficient to prevent progression of retinal nonperfusion, which may contribute to loss of visual gains. [ABSTRACT FROM AUTHOR]

Purpose To assess changes in retinal nonperfusion (RNP) in patients with retinal vein occlusion (RVO) treated with ranibizumab. Design Secondary outcome measure in randomized double-masked controlled clinical trial. Participants Thirty-nine patients with central RVO (CRVO) and 42 with branch RVO (BRVO). Methods Subjects were randomized to 0.5 or 2.0 mg ranibizumab every month for 6 months and then were re-randomized to pro re nata (PRN) groups receiving either ranibizumab plus scatter laser photocoagulation or ranibizumab alone for an additional 30 months. Main Outcome Measures Comparison of percentage of patients with increased or decreased area of RNP in patients with RVO treated with 0.5 versus 2.0 mg ranibizumab, during monthly injections versus ranibizumab PRN, and in patients treated with ranibizumab PRN versus ranibizumab PRN plus laser. Results In RVO patients given monthly injections of 0.5 or 2.0 mg ranibizumab for 6 months, there was no significant difference in the percentage who showed reduction or increase in the area of RNP. However, regardless of dose, during the 6-month period of monthly injections, a higher percentage of patients showed a reduction in area of RNP and a lower percentage showed an increase in area of RNP compared with subsequent periods of ranibizumab PRN treatment. After the 6-month period of monthly injections, BRVO patients, but not CRVO patients, randomized to ranibizumab PRN plus laser showed significantly less progression of RNP compared with patients treated with ranibizumab PRN. Conclusions Regardless of dose (0.5 or 2.0 mg), monthly ranibizumab injections promote improvement and reduce progression of RNP compared with PRN injections. The addition of scatter photocoagulation to ranibizumab PRN may reduce progression of RNP in patients with BRVO, but a statistically significant reduction was not seen in patients with CRVO. [ABSTRACT FROM AUTHOR]