Serum cholesterol concentration associated with aspirin esterase activity in older people: preliminary data

Clinical significance of pre-surgical serum lipid levels in patients with glioblastoma

Accumulating evidence demonstrates that pre-surgical serum lipid levels are linked to the clinical outcome of different types of human malignant tumors, but few studies have explored the prognostic value of these easily accessible parameters in glioblastoma. The aim of the current study was to validate the association between pre-surgical serum lipid levels and the clinical outcome of patients with glioblastoma. The pre-surgical serum lipid levels (triglycerides, total cholesterol, high-density lipoprotein [HDL] cholesterol, and low-density lipoprotein [LDL] cholesterol) of 125 patients with glioblastoma, who underwent surgery between January 2015 and May 2016, were retrospectively evaluated. The correlation between pre-surgical serum lipid levels and overall survival (OS) was examined using the Kaplan-Meier method and Cox proportional hazards regression model. Univariate analysis showed that lipids associated with OS were total cholesterol, HDL cholesterol, and LDL cholesterol levels. Results of multivariate analysis identified LDL cholesterol level as an independent prognostic factor for OS in patients with glioblastoma (hazard ratio: 0.412; 95% confidence interval: 0.211-0.801; P = 0.009). Total cholesterol and HDL cholesterol levels were predictive factors only in univariate analysis, but not in multivariate analysis. The current study demonstrated that pre-surgical serum LDL cholesterol level is an independent prognostic factor for clinical outcomes of patients with glioblastoma. Pre-surgical serum LDL cholesterol level might provide valuable prognostic information for patients with glioblastoma that could be applied in clinical practice.

Mechanisms of aspirin resistance

Aspirin is integral to the secondary prevention of cardiovascular disease and acts to impair the development of platelet-mediated atherothromboembolic events by irreversible inhibition of platelet cyclooxygenase-1 (COX-1). Inhibition of this enzyme prevents the synthesis of the potent pro-aggregatory prostanoid thromboxane A2. A large number of patients continue to experience atherothromboembolic events despite aspirin therapy, so-called 'aspirin treatment failure', and this is multifactorial in aetiology. Approximately 10% however do not respond appropriately to aspirin in a phenomenon known as 'aspirin resistance', which is defined by various laboratory techniques. In this review we discuss the reasons for aspirin resistance in a systematic manner, starting from prescription of the drug and ending at the level of the platelet. Poor medication adherence has been shown to be a cause of apparent aspirin resistance, and may in fact be the largest contributory factor. Also important is high platelet turnover due to underlying inflammatory processes, such as atherosclerosis and its complications, leading to faster regeneration of platelets, and hence of COX-1, at a rate that diminishes the efficacy of once daily dosing. Recent developments include the identification of platelet glycoprotein IIIa as a potential biomarker (as well as possible underlying mechanism) for aspirin resistance and the discovery of an anion efflux pump that expels intracellular aspirin from platelets. The absolute as well as relative contributions of such factors to the phenomenon of aspirin resistance are the subject of continuing research.