Activation of the NFAT–calcium signaling pathway in human lamina cribrosa cells in glaucoma

Purpose: Optic nerve cupping in glaucoma is characterized by remodeling of the extracellular matrix (ECM) and fibrosis in the lamina cribrosa (LC). We have previously shown that glaucoma LC cells express raised levels of ECM genes and have elevated intracellular calcium ([Ca2+]i). Raised [Ca2+]i is known to promote proliferation, activation, and contractility in fibroblasts via the calcineurin–NFAT (nuclear factor of activated T-cells) signaling pathway. In this study, we examine NFAT expression in normal and glaucoma LC cells, and investigate the effect of cyclosporin A (CsA, a known inhibitor of NFAT activity) on [Ca2+]i and ECM gene expression in normal and glaucoma LC cells. Methods: [Ca2+]i was measured with dual-wavelength Ca2+ imaging and confocal microscopy using Fura-2-AM and Fluo-4 under physiological isotonic and hypotonic cell stretch treatment. Human donor LC cells were cultured under normal physiological conditions or using a glaucoma-related stimulus, oxidative stress (H2O2, 100 μM), for 6 hours with or without CsA. NFATc3 protein levels were examined using Western blot analysis. Profibrotic ECM gene transcription (including transforming growth factor-β1 [TGFβ1], collagen 1A1 [Col1A1], and periostin) was analyzed using quantitative real time RT-PCR. Results: Basal and hypotonic cell membrane stretch-induced [Ca2+]i were significantly (P < 0.05) elevated in glaucoma LC cells compared to normal controls. There was a significant delay in [Ca2+]i reuptake into internal stores in the glaucoma LC cells. NFATc3 protein levels were increased in glaucoma LC cells. CsA (10 μM) significantly inhibited the H2O2-induced expression of NFATc3 in normal and glaucoma LC cells. CsA also reduced the H2O2-induced NFATc3 dephosphorylation (and nuclear translocation), and also suppressed the H2O2-induced elevation in profibrotic ECM genes (TGFβ1, Col1A1, and periostin), both in normal and in glaucoma LC cells. Conclusions: Intracellular Ca2+ and NFATc3 expression were significantly increased in glaucoma LC cells. CsA reduced the H2O2-induced enhancement in NFATc3 protein expression and nuclear translocation and the profibrotic gene expression both in normal and in glaucoma LC cells. Therefore, targeting the calcineurin–NFATc3 signaling pathway may represent a potential avenue for treating glaucoma-associated LC fibrosis

Growth Patterns in the Irish Pyridoxine Nonresponsive Homocystinuria Population and the Influence of Metabolic Control and Protein Intake

A low methionine diet is the mainstay of treatment for pyridoxine nonresponsive homocystinuria (HCU). There are various guidelines for recommended protein intakes for HCU and clinical practice varies. Poor growth has been associated with low cystine levels. This retrospective review of 48 Irish pyridoxine nonresponsive HCU patients assessed weight, height, body mass index (BMI), protein intake, and metabolic control up to 18 years at nine set time points. Patients diagnosed through newborn screening (NBS) were compared to late diagnosed (LD) patients. At 18 years the LD group (n=12, mean age at diagnosis 5.09 years) were heavier (estimated effect +4.97 Kg, P=0.0058) and taller (estimated effect +7.97 cm P=0.0204) than the NBS group (n=36). There was no difference in growth rate between the groups after 10 years of age. The HCU population were heavier and taller than the general population by one standard deviation with no difference in BMI. There was no association between intermittently low cystine levels and height. Three protein intake guidelines were compared; there was no difference in adult height between those who met the lowest of the guidelines (Genetic Metabolic Dietitians International) and those with a higher protein intake

Experimental observations of CO2-water-basaltic glass interaction in a large column reactor experiment at 50 °C

Publisher's version (útgefin grein).Mineralization of water dissolved carbon dioxide injected into basaltic rocks occurs within two years in field-scale settings. Here we present the results from a CO2-water-basaltic glass laboratory experiment conducted at 50 °C and 80 bar pressure in a Ti high-pressure column flow reactor. We explore the possible sequence of saturation with Fe-Mg-Ca-carbonate minerals versus Fe-Mg-clay and Ca-zeolite saturation states, which all compete for divalent cations and pore space during injection of CO2 into basaltic rocks. Pure water (initially with atmospheric CO2) – basaltic glass reactions resulted in high pH (9–10) water saturated with respect to Mg-Fe-clays (saponites), Ca-zeolites, and Ca-carbonate. As CO2-charged water (˜20 mM) entered the column and mixed with the high pH water, all the Fe-Mg-Ca-carbonates became temporarily supersaturated along with clays and zeolites. Injected waters with dissolved CO2 reached carbonate mineral saturation within 12 h of fluid-rock interaction. Once the pH of the outflow water stabilized below 6, siderite was the only thermodynamically stable carbonate throughout the injection period, although no physical evidence of its precipitation was found. When CO2 injection stopped while continuing to inject pure water, pH rose rapidly in the outflow and all carbonates became undersaturated, whereas zeolites became more saturated and Mg-Fe-saponites supersaturated. Resuming CO2 injection lowered the pH from >8 to about 6, resulting in an undersaturation of the clays and Na-zeolites. These results along with geochemical modelling underscore the importance of initial pCO2 and pH values to obtain a balance between the formation of carbonates versus clays and zeolites. Moreover, modelling indicates that pauses in CO2 injection while still injecting water can result in enhanced large molar volume Ca-Na-zeolite and Mg-Fe-clay formation that consumes pore space within the rocks.This publication has been produced with support from the European Commission through the projects CarbFix (EC Project 283148), CO2-React (EC Project 317235), and S4CE (EC Project 764810). The authors would like to thank editor Charles Jenkins for handling the manuscript and to the anonymous reviewers for their constructive comments that helped improve the manuscript. Special thanks to Giulia Alessandrini for her indispensable assistance in running the experiment, Sydney Gunnarson for material preparation, and Þorsteinn Jónsson for preparing, setting up, and taking apart the column. We would also like to acknowledge Rebecca Neely and Tobias Linke for their help in the laboratory in addition to Eric Oelkers, Peter Rendel, and the CarbFix group for their support.Peer Reviewe