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Objectives: This meta-analysis was performed to determine the effects of various cholesterol-lowering treatments on the risk of stroke and its relationship with the extent of cholesterol lowering., Background: Statins reduce the incidence of stroke, and it has been proposed that such effect is independent of cholesterol lowering and is explained by alternative mechanisms., Methods: We performed a meta-analysis of randomized trials of cholesterol-lowering treatments in cardiovascular disease reporting on stroke, involving 266,973 patients investigated and a cumulative 946,582 person-years of exposure, and a meta-regression analysis of the extent of stroke reduction as a function of changes in total cholesterol., Results: The odds ratio (OR) for the incidence of stroke in actively treated groups versus controls was 0.88 (95% confidence interval: 0.83 to 0.94, p < 0.001). No treatment affected fatal strokes. Whereas statins decreased the risk of total stroke significantly (OR: 0.85, 95% confidence interval: 0.78 to 0.92; p < 0.001), the benefit of nonstatin interventions was smaller and not statistically significant (diet OR: 0.92, fibrates OR: 0.98, other treatments OR: 0.81). We found a significant relationship between percent reduction of total (and low-density lipoprotein) cholesterol and percent reduction of total strokes (p = 0.0017), with each 1% reduction of total cholesterol predicting a 0.8% relative risk reduction of stroke. We found no significant association between stroke reduction and changes of high-density lipoprotein cholesterol levels, and inconsistent associations with reduction of triglycerides., Conclusions: Among cholesterol-lowering treatments, statins are the most effective at decreasing the risk of total stroke, but their benefit is proportional to the percent reduction of total cholesterol and low-density lipoprotein cholesterol. No lipid-lowering intervention was associated with a reduction of fatal stroke., (Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: Erythropoietin has been shown to have a protective effect in certain models of ischaemia-reperfusion, and in some cases the protection has been correlated with activation of signalling pathways known to play a role in cell survival and proliferation. We have studied whether erythropoietin would overcome direct toxic effects of hydrogen peroxide (H(2)O(2)) treatment to human renal proximal tubular (HK-2) cells., Materials and Methods: HK-2 cells were incubated with H(2)O(2) (2 mm) for 2 h with or without erythropoietin at concentrations of 100 and 400 U/ml, and cell viability/proliferation was assessed by chemical reduction of MTT. Changes in phosphorylation state of the kinases Akt, glycogen synthase kinase-3beta (GSK-3beta), mammalian target of rapamycin (mTOR) and extracellular signal-regulated kinase 1 and 2 (ERK1/ERK2) were also analysed., Results: Cells incubated with H(2)O(2) alone showed a significant decrease in viability, which did not significantly change by addition of erythropoietin at concentration of 100 U/ml, but was further reduced when concentration of erythropoietin was increased to 400 U/ml. Phosphorylation state of the kinases Akt, GSK-3beta, mTOR and ERK1/ERK2 of H(2)O(2)-treated HK-2 cells was slightly altered in the presence of erythropoietin at concentration of 100 U/ml, but was significantly less in the presence of erythropoietin at a concentration of 400 U/ml. Phosphorylation of forkhead transcription factor FKHRL1 was diminished in cells incubated with H(2)O(2) and erythropoietin at a concentration of 400 U/ml., Conclusions: Erythropoietin, at high concentrations, may significantly increase cellular damage in HK-2 cells subjected to oxidative stress, which may be due in part to decrease in activation of important signalling pathways involved in cell survival and/or cell proliferation.