Low apo-AI is independently related to 30-day mortality in human sepsis and the decrease in apo-AI/HDL cholesterol correlates to increased platelet activation. Moreover, changes in apolipoproteins supposed to modulate lipopolysaccharide effects, such as apo-CI and apo-E, correlate to monocyte activation.

SummaryThrombophilia is a well-established risk factor for a venous thromboembolic event (VTE), and it has been proposed that hereditary thrombophilia may substantially contribute to the development of VTE in young patients. We aimed to analyse the prevalence of thrombophilia with special regard to the age of VTE manifestation. The study cohort consisted of 1490 patients (58% females) with a median age 43 years at the time of their first VTE. At least one thrombophilic disorder was identified in 50Á1% of patients. The probability of detecting a hereditary thrombophilia declined significantly with advancing age (from 49Á3% in patients aged 20 years and younger to 21Á9% in patients over the age of 70 years; P < 0Á001). This may be primarily attributed to the decreasing frequencies of the F5 R506Q (factor V Leiden) mutation and deficiencies of protein C or protein S with older age at the time of the initial VTE event. Moreover, thrombophilia was more prevalent in unprovoked compared with risk-associated VTE (57Á7% vs. 47Á7%; P = 0Á001). The decline in the prevalence of hereditary thrombophilia with older ages supports the use of a selected thrombophilia screening strategy dependent on age and the presence or absence of additional VTE risk factors.

Aminopeptidase N (CD13) was recently identified as a molecular target of the cholesterol absorption inhibitor Ezetimib. Regarding that CD13 is expressed in lipid rafts of monocytic cells, we have investigated whether Ezetimib influences raft function in these cells. Expression of raft‐associated antigens (CD11b, CD13, CD14, CD16, CD36, and CD64) was followed by flow cytometry and/or immunoblot in human monocyte‐derived macrophages in response to in vitro administration of Ezetimib. Cellular redistribution of CD13 was assessed by confocal imaging. Ezetimib significantly decreased the surface expression of CD13, CD16, CD64, and CD36; furthermore, it induced a shift of CD13 from plasma membrane to intracellular vesicles, and thus it quite likely modulated monocytic raft‐assembly. © 2006 International Society for Analytical Cytology

Background: Lipid membrane microdomains are involved in the regulation of biological functions of monocyte membrane proteins. These microdomains show a relative resistance to non‐ionic detergents providing an easy analytical tool to study them. Methods: Here, we applied a rapid detergent‐based flow cytometric assay to investigate microdomain association of proteins on monocytes from whole blood samples. The association of known surface antigens with detergent resistant fraction of membranes (DRMs) was compared using monocytes from healthy blood donors, patients with genetic disorders affecting cellular cholesterol traffic and patients with systemic inflammatory response. Results: All investigated surface antigens of Niemann‐Pick type C (NPC)‐mutant monocytes with impaired cholesterol influx and defective late endosome cholesterol trafficking, presented a strongly increased DRM‐association. Though, membrane antigens of ATP binding cassette transporter A1 (ABCA1)‐mutant monocytes with impaired cholesterol efflux did not show alterations in DRM‐association. Differential CD14‐dependent receptor clustering within microdomains was also investigated in response to in vivo lipopolysaccharide (LPS) and/or atherogenic lipoprotein activation. Increased DRM‐association of the GPI‐anchored proteins CD14, CD55, the Fcγ receptor CD64, the scavenger receptors CD36, CD91 and CD163, the integrin CD11a, and complement receptor 3 complex CD11b/CD18 were observed from patients with systemic inflammatory response syndrome (SIRS)/sepsis or coronary artery disease (CAD)/myocardial infarction. Interestingly, the tetraspanin CD81 presented increased DRM‐association in SIRS/sepsis patients, but not in CAD patients. Moreover, the pentaspanin CD47 and the Fcγ RIII CD16 showed an increased DRM partition in CAD patients but disassembled from DRMs in SIRS/sepsis patients. Conclusions: Our results demonstrate that flow cytometric analysis of short time in situ detergent extraction provides a powerful tool for rapid screening of blood monocyte DRMs to preselect patients with potential raft/microdomain abnormalities for more detailed analysis. © 2007 International Society for Analytical Cytology