Increased Angiopoietin-1 and -2 levels in human vitreous are associated with proliferative diabetic retinopathy.

BACKGROUND: Diabetic retinopathy is a frequent complication of diabetes mellitus and a leading cause of blindness in adults. The objective of this study was to elucidate the diabetic retinopathy pathophysiology in more detail by comparing protein alterations in human vitreous of different diabetic retinopathy stages. METHODS: Vitreous samples were obtained from 116 patients undergoing pars plana vitrectomy. Quantitative immunoassays were performed of angiogenic factors (VEGF-A, PIGF, Angiopoietin-1, Angiopoietin-2, Galectin-1) as well as cytokines (IL-1ß, IL-8, IFN-γ, TNF-α, CCL3) in samples from control patients (patients who don't suffer from diabetes; n = 58) as well as diabetes mellitus patients without retinopathy (n = 25), non-proliferative diabetic retinopathy (n = 12), and proliferative diabetic retinopathy patients (n = 21). In addition, correlation analysis of protein levels in vitreous samples and fasting glucose values of these patients as well as correlation analyses of protein levels and VEGF-A were performed. RESULTS: We detected up-regulated levels of VEGF-A (p = 0.001), PIGF (p<0.001), Angiopoietin-1 (p = 0.005), Angiopoietin-2 (p<0.001), IL-1ß (p = 0.012), and IL-8 (p = 0.018) in proliferative diabetic retinopathy samples. Interestingly, we found a strong positive correlation between Angiopoietin-2 and VEGF-A levels as well as a positive correlation between Angiopoietin-1 and VEGF-A. CONCLUSION: This indicated that further angiogenic factors, besides VEGF, but also pro-inflammatory cytokines are involved in disease progression and development of proliferative diabetic retinopathy. In contrast, factors other than angiogenic factors seem to play a crucial role in non-proliferative diabetic retinopathy development. A detailed breakdown of the pathophysiology contributes to future detection and treatment of the disease.

Gum Arabic Nanoparticles as Green Corrosion Inhibitor for Reinforced Concrete Exposed to Carbon Dioxide Environment.

The inhibiting effect of Gum Arabic-nanoparticles (GA-NPs) to control the corrosion of reinforced concrete that exposed to carbon dioxide environment for 180 days has been investigated. The steel reinforcement of concrete in presence and absence of GA-NPs were examined using various standard techniques. The physical/surface changes of steel reinforcement was screened using weight loss measurement, electrochemical impedance spectroscopy (EIS), atomic force microscopy and scanning electron microscopy (SEM). In addition, the carbonation resistance of concrete as well screened using visual inspection (carbonation depth), concrete alkalinity (pH), thermogravimetric analysis (TGA), SEM, energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The GA-NPs inhibitor size was also confirmed by transmission electron microscopy (TEM). The results obtained revealed that incorporation of 3% GA-NPs inhibitor into concrete inhibited the corrosion process via adsorption of inhibitor molecules over the steel reinforcement surface resulting of a protective layer formation. Thus, the inhibition efficiency was found to increase up-to 94.5% with decreasing corrosion rate up-to 0.57 × 10-3 mm/year. Besides, the results also make evident the presence of GA-NPs inhibitor, ascribed to the consumption of calcium hydroxide, and reduced the Ca/Si to 3.72% and 0.69% respectively. Hence, C-S-H gel was developed and pH was increased by 9.27% and 12.5, respectively. It can be concluded that green GA-NPs have significant corrosion inhibition potential and improve the carbonation resistance of the concrete matrix to acquire durable reinforced concrete structures.