A water-soluble fullerene vesicle alleviates angiotensin II-induced oxidative stress in human umbilical venous endothelial cells.

A water-soluble fullerene vesicle based on the Buckminsterfullerene molecule (Ph(5)C(60)K, denoted as PhK) was explored to determine its effects on anti-oxidation of human umbilical endothelial cells (HUVEC) exposed to exogenous and endogenous reactive oxygen species (ROS). Hydrogen peroxide 0.05-0.25 mmol/L remarkably reduced the cellular viability of HUVEC. This reduction in viability was markedly improved when PhK 0.01-1 micromol/L was added simultaneously to the culture medium. The reduction of viability in HUVEC induced by angiotensin II (AII) 10(-9) to 10(-7) mol/L was improved by pretreatment with PhK 0.1 or 10 micromol/L 12 h before AII stimulation. The ROS indicator CM-H(2)DCFDA demonstrated the efficacy of PhK 1 or 10 micromol/L in decreasing AII-induced ROS production to the level induced by the AII receptor blocker RNH-6470 20 micromol/L. The AII-induced peroxynitrite formation, as gauged using hydroxyphenyl fluorescein as a probe, was alleviated significantly by either pretreatment with PhK 0.1 or 1 micromol/L. Electron microscopy revealed intracellular localization of PhK in HUVEC after 12 h incubation. The PhK decreased the AII-induced apoptosis and lipid peroxidation processes as revealed by hexanoyl-lysine adduct formation. These observations show that the PhK water-soluble fullerene vesicle is promising as a compound controlling not only exogenous ROS, but also endogenous AII-mediated pathophysiological conditions.

Urinary human L-FABP is a potential biomarker to predict COX-inhibitor-induced renal injury.

BACKGROUND/AIM: A strong demand exists for the development of sensitive biomarkers in the nephrology field. We propose urinary human L-type fatty acid binding protein (L-FABP) as an earlier biomarker to detect the outcome of chronic renal injury induced by cyclooxygenase (COX) inhibitors using human L-FABP transgenic mice. METHODS: After consuming a low-sodium diet for 2 weeks, transgenic mice were administered meloxicam or celecoxib with the low-sodium diet. Mice were sacrificed 2 days and 4 weeks after starting COX inhibitors, and urine was collected 24 and 48 h and 1, 2, 3, and 4 weeks after starting COX inhibitors. Celecoxib-treated mice were divided into responders or nonresponders according to urinary L-FABP levels, and histology, urinary L-FABP and peritubular capillary blood flow were evaluated. RESULTS: Meloxicam-treated mice showed a higher blood pressure than control mice. Urinary L-FABP was significantly increased in COX inhibitor-treated mice. Peritubular capillary blood flow in all meloxicam-treated mice and in some celecoxib-treated mice was significantly decreased. Although blood urea nitrogen was not increased, interstitial fibrosis and macrophage infiltration were revealed, especially in meloxicam-treated mice. Responders showed an increase of fibrotic areas and correlations between urinary L-FABP and peritubular capillary blood flow. CONCLUSION: Urinary L-FABP is capable of revealing chronic renal injury induced by COX inhibitors.

Functional polymorphism of the myeloperoxidase gene in hypertensive nephrosclerosis dialysis patients.

Myeloperoxidase (MPO) may play an important role not only in host defense reactions but also in local inflammations, especially in atherosclerotic diseases such as hypertensive nephrosclerosis (HN). Paradoxically, MPO-deficient mice have been reported to show increased atherosclerosis compared with wild mice, although higher MPO levels are thought to exacerbate atherosclerotic disease. To clarify the genetic role of MPO in HN, we examined the function and distribution of the -463G/A polymorphism located in the promoter region of the MPO gene with ex vivo flow cytometry analysis and a study in end-stage renal disease patients, respectively. This polymorphism has been reported to have a functional significance in vitro, with the A allele being associated with lower MPO expression. In the present study, we also found significantly higher reactive oxygen species (ROS) production with peripheral neutrophils isolated from subjects with the GG genotype compared with those from subjects with other genotypes by flow cytometry assay with 2-[6-(4'-amino) phenoxy-3H-xanthen-3-on-9-yl] benzoic acid (APF), which shows higher sensitivity with hypochlorite (OCl(-)). Genotyping the -463G/A polymorphism in HN, chronic glomerulonephritis (CGN) and diabetic nephropathy (DM) patients who were under hemodialysis treatment demonstrated that the GG genotype was more frequent in the HN group than in the CGN and DM groups. However, the distribution of the GG genotype in the HN group was similar to that in healthy individuals. Although the -463G/A polymorphism is associated with ROS production, careful interpretation may be required to conclude that the -463G/A polymorphism can serve as a useful marker of atherosclerosis and cardiovascular events in dialysis patients.