Kita T, Clermont AC, Murugesan N, Zhou Q, Fujisawa K, Ishibashi T, Aiello LP, Feener EP.
Plasma Kallikrein-Kinin System as a VEGF-Independent Mediator of Diabetic Macular Edema. Diabetes 2015;64(10):3588-99.
AbstractThis study characterizes the kallikrein-kinin system in vitreous from individuals with diabetic macular edema (DME) and examines mechanisms contributing to retinal thickening and retinal vascular permeability (RVP). Plasma prekallikrein (PPK) and plasma kallikrein (PKal) were increased twofold and 11.0-fold (both P < 0.0001), respectively, in vitreous from subjects with DME compared with those with a macular hole (MH). While the vascular endothelial growth factor (VEGF) level was also increased in DME vitreous, PKal and VEGF concentrations do not correlate (r = 0.266, P = 0.112). Using mass spectrometry-based proteomics, we identified 167 vitreous proteins, including 30 that were increased in DME (fourfold or more, P < 0.001 vs. MH). The majority of proteins associated with DME displayed a higher correlation with PPK than with VEGF concentrations. DME vitreous containing relatively high levels of PKal and low VEGF induced RVP when injected into the vitreous of diabetic rats, a response blocked by bradykinin receptor antagonism but not by bevacizumab. Bradykinin-induced retinal thickening in mice was not affected by blockade of VEGF receptor 2. Diabetes-induced RVP was decreased by up to 78% (P < 0.001) in Klkb1 (PPK)-deficient mice compared with wild-type controls. B2- and B1 receptor-induced RVP in diabetic mice was blocked by endothelial nitric oxide synthase (NOS) and inducible NOS deficiency, respectively. These findings implicate the PKal pathway as a VEGF-independent mediator of DME.
Kothari S, Foster SC, Pistilli M, Liesegang TL, Daniel E, Sen NH, Suhler EB, Thorne JE, Jabs DA, Levy-Clarke GA, Nussenblatt RB, Rosenbaum JT, Lawrence SD, Kempen JH, for Eye Diseases Group SITR.
The Risk of Intraocular Pressure Elevation inPediatric Noninfectious Uveitis. Ophthalmology 2015;122(10):1987-2001.
AbstractPURPOSE: To characterize the risk and risk factors for intraocular pressure (IOP) elevation in pediatric noninfectious uveitis. DESIGN: Multicenter retrospective cohort study. PARTICIPANTS: Nine hundred sixteen children (1593 eyes) younger than 18 years at presentation with noninfectious uveitis followed up between January 1978 and December 2007 at 5 academic uveitis centers in the United States. METHODS: Medical records review by trained, certified experts. MAIN OUTCOME MEASURES: Prevalence and incidence of IOP of 21 mmHg or more and 30 mmHg or more and incidence of a rise in IOP by 10 mmHg or more. To avoid underascertainment, outcomes were counted as present when IOP-lowering therapies were in use. RESULTS: Initially, 251 (15.8%) and 46 eyes (2.9%) had IOP ≥21 mmHg and ≥30 mmHg, respectively. Factors significantly associated with presenting IOP elevation included age of 6 to 12 years (versus other pediatric ages), prior cataract surgery, pars plana vitrectomy, duration of uveitis ≥6 months, contralateral IOP elevation, presenting visual acuity worse than 20/40, and topical corticosteroid use (in a dose-response relationship). The median follow-up was 1.25 years (interquartile range, 0.4-3.66). The estimated incidence of any observed IOP elevation to ≥21 mmHg, to ≥30 mmHg, and increase in IOP by ≥10 mmHg was 33.4%, 14.8%, and 24.4%, respectively, within 2 years. Factors associated with IOP elevation included pars plana vitrectomy, contralateral IOP elevation (adjusted hazard ratio [aHR], up to 9.54; P < 0.001), and the use of topical (aHR, up to 8.77 that followed a dose-response relationship; P < 0.001), periocular (aHR, up to 7.96; P < 0.001), and intraocular (aHR, up to 19.7; P < 0.001) corticosteroids. CONCLUSIONS: Intraocular pressure elevation affects a large minority of children with noninfectious uveitis. Statistically significant risk factors include IOP elevation or use of IOP-lowering treatment in the contralateral eye and local corticosteroid use that demonstrated a dose-and route of administration-dependent relationship. In contrast, use of immunosuppressive drug therapy did not increase such risk. Pediatric eyes with noninfectious uveitis should be followed up closely for IOP elevation, especially when strong risk factors such as the use of local corticosteroids and contralateral IOP elevation are present.
Kovacs K, Marra KV, Yu G, Wagley S, Ma J, Teague GC, Nandakumar N, Lashkari K, Arroyo JG.
Angiogenic and Inflammatory Vitreous Biomarkers Associated With Increasing Levels of Retinal Ischemia. Invest Ophthalmol Vis Sci 2015;56(11):6523-30.
AbstractPURPOSE: To characterize the angiogenic and inflammatory vitreous biomarker profiles in a spectrum of ischemic retinopathies, including neovascular glaucoma. METHODS: This institutional review board-approved study retrospectively analyzed 80 undiluted vitreous samples obtained during pars vitrectomy. The specimens were frozen (-80°C) and sent for concentration analysis of 34 proteins by Bio-Plex Pro assays. Specimens were divided into four groups: patients undergoing epiretinal membrane (ERM) peeling and/or macular hole (MH) surgery with no history of diabetes (non-DM group), patients undergoing ERM peeling, and/or MH surgery with a history of diabetes (DM group), patients with proliferative diabetic retinopathy (PDR group), and patients with neovascular glaucoma (NVG group). Parametric and nonparametric analyses of demographics and cytokine levels were performed using SPSS. RESULTS: There were no significant differences in demographics among cohorts. Numerous proteins were significantly elevated between non-DM and DM (G-CSF, sCD40L, Endoglin, IL-6, placental growth factor [PlGF], VEGF-D), DM and PDR (leptin, IL-8, PlGF, VEGF-A), and PDR and NVG (G-CSF, leptin, TIE-2, sCD40L, EGF, HB-EGF, IL-6, IL-8, PlGF, TNF-α). Only PlGF was significantly elevated between each successive cohort. The most potent drivers of NVG were PlGF, VEGF-A, IL-6, and IL-8. CONCLUSIONS: While the role of angioproliferative growth factors is well documented in ischemic retinopathy, our study delineates the importance of inflammatory and previously underreported angiogenic proteins. It also demonstrates a significant incremental increase in certain factors with increasing levels of ischemia. Both of these findings may guide the development of future therapies for ischemic retinopathies.