[Recommendations for management of dyslipidemia in 2014]

Benefit of statin treatment is well established for secondary prevention. For primary prevention, good data exist to support use of statins in high-risk groups. Less data are available for intermediate risk group and very few patients at low risk have been included in clinical trials. In this context, an individual approach based on a risk stratification using PROCAM score adjusted for Switzerland is recommended. Lifestyle measures should be tried first. We also discuss the new American guidelines and their related controversies. Secondary causes and familiar forms of dyslipidemias, for which a risk assessment cannot be performed using risk scores (first cardiovascular event between age 20 and 60), should not be overlooked.

Effect of a mixture of bovine milk oligosaccharides, Lactobacillus rhamnosus NCC4007 and long-chain polyunsaturated fatty acids on catch-up growth of intra-uterine growth-restricted rats

AIM

To investigate the effect of a nutritional mixture (bovine milk oligosaccharides, Lactobacillus rhamnosus NCC4007, arachidonic and docosahexaenoic acid) on growth of intrauterine growth-restricted (IUGR) rats.

METHODS

IUGR was induced by maternal food restriction. The offspring (males and females) were assigned to: REF (non-IUGR, no mixture), IUGRc (IUGR, no mixture), or IUGRmx (IUGR, mixture). The mixture was given from day 7 to day 58, when tissues and plasma from half of the animals were collected for hormones, metabolites and microarray analysis. The rest received a high-fat diet (HFD) until day 100. Glucose tolerance was measured at 56 and 98 days, and body fat content at 21, 52 and 97 days.

RESULTS

IUGRmx had the greatest growth during lactation, but from day 22 to day 54, both IUGR groups gained less body weight than the REF (P < 0.05). In the short-term (58 days), IUGRmx tended to be longer (P = 0.06) and had less body fat (P = 0.03) than IUGRc. These differences were not seen after HFD. Microarray analysis of hepatic mRNA expression at 58 and 100 days revealed a gender-dependent treatment effect, and expression of genes related to lipid metabolism was the most affected. Twelve of these genes were selected for studying differences in DNA methylation in the promoter region, for some, we observed age- and gender-related differences but none because of treatment.

CONCLUSION

The nutritional intervention promoted catch-up growth and normalized excessive adiposity in IUGR animals at short-term. The benefits did not extend after a period of HFD. IUGR and early diet had gender-dependent effects on hepatic gene expression.

The mechanism of kindlin-mediated activation of integrin αIIbβ3

Increased ligand binding to cellular integrins ("activation") plays important roles in processes such as development, cell migration, extracellular matrix assembly, tumor metastasis, hemostasis, and thrombosis. Integrin activation encompasses both increased integrin monomer affinity and increased receptor clustering and depends on integrin-talin interactions. Loss of kindlins results in reduced activation of integrins. Kindlins might promote talin binding to integrins through a cooperative mechanism; however, kindlins do not increase talin association with integrins. Here, we report that, unlike talin head domain (THD), kindlin-3 has little effect on the affinity of purified monomeric αIIbβ3, and it does not enhance activation by THD. Furthermore, studies with ligands of varying valency show that kindlins primarily increase cellular αIIbβ3 avidity rather than monomer affinity. In platelets or nucleated cells, loss of kindlins markedly reduces αIIbβ3 binding to multivalent but not monovalent ligands. Finally, silencing of kindlins reduces the clustering of ligand-occupied αIIbβ3 as revealed by total internal reflection fluorescence and electron microscopy. Thus, in contrast to talins, kindlins have little primary effect on integrin αIIbβ3 affinity for monovalent ligands and increase multivalent ligand binding by promoting the clustering of talin-activated integrins.

LMX1B is essential for the maintenance of differentiated podocytes in adult kidneys

Mutations of the LMX1B gene cause nail-patella syndrome, a rare autosomal-dominant disorder affecting the development of the limbs, eyes, brain, and kidneys. The characterization of conventional Lmx1b knockout mice has shown that LMX1B regulates the development of podocyte foot processes and slit diaphragms, but studies using podocyte-specific Lmx1b knockout mice have yielded conflicting results regarding the importance of LMX1B for maintaining podocyte structures. In order to address this question, we generated inducible podocyte-specific Lmx1b knockout mice. One week of Lmx1b inactivation in adult mice resulted in proteinuria with only minimal foot process effacement. Notably, expression levels of slit diaphragm and basement membrane proteins remained stable at this time point, and basement membrane charge properties also did not change, suggesting that alternative mechanisms mediate the development of proteinuria in these mice. Cell biological and biophysical experiments with primary podocytes isolated after 1 week of Lmx1b inactivation indicated dysregulation of actin cytoskeleton organization, and time-resolved DNA microarray analysis identified the genes encoding actin cytoskeleton-associated proteins, including Abra and Arl4c, as putative LMX1B targets. Chromatin immunoprecipitation experiments in conditionally immortalized human podocytes and gel shift assays showed that LMX1B recognizes AT-rich binding sites (FLAT elements) in the promoter regions of ABRA and ARL4C, and knockdown experiments in zebrafish support a model in which LMX1B and ABRA act in a common pathway during pronephros development. Our report establishes the importance of LMX1B in fully differentiated podocytes and argues that LMX1B is essential for the maintenance of an appropriately structured actin cytoskeleton in podocytes.

Radiofrequency ablation technique in the treatment of liver tumours: review and future issues

Thermal ablation is increasingly being used for treatment of liver tumours. Among the techniques of thermal ablation, radiofrequency ablation (RF) is undoubtedly being used most frequently because of its advantages, such as morbidity and mortality rates, effective tumour ablation, as well as being less time-consuming. This paper presents the state of the art of RF ablation technique. This includes the theoretical development, experimental study and clinical application of the radiofrequency ablation technique. First, it introduces the principle of this technique. Second, it shows the development of this technique and valuable achievements. These achievements include the device, strategy of operation and extension to other diseases. Third, it concludes future issues to be addressed in order to further advance this technique.

Thrombin receptor antagonism in antiplatelet therapy

Activated platelets play a crucial role in the pathogenesis of atherothrombotic disease and its complications. Even under treatment of antiplatelet drugs, such as acetylsalicylic acid and P2Y12 antagonists, morbidity and mortality rates of thromboembolic complications remain high. Hence, the therapeutic inhibition of protease-activated receptor (PAR)-1, which is activated by thrombin, is a novel promising approach in antiplatelet therapy. Recent data suggest that PAR-1 is mainly involved in pathological thrombus formation, but not in physiological hemostasis. Therefore, PAR-1 inhibition offers the possibility to reduce atherothrombotic events without increasing bleeding risk. So far, two emerging PAR-1 antagonists have been tested in clinical trials: vorapaxar (SCH530349; Merck & Co., Whitehouse Station, NJ, USA) and atopaxar (E5555; Eisai, Tokyo, Japan). Although in TRA-CER vorapaxar showed an unfavorable profile for patients with acute coronary syndrome in addition to standard therapy, it revealed promising results for patients with prior myocardial infarction in TRA 2P-TIMI50. Depending on the status of clinical approval, vorapaxar might be an option for patients with peripheral arterial disease to reduce limb ischemia. The second PAR-I antagonist, atopaxar, tended towards reducing major cardiovascular adverse events in acute coronary syndrome patients in a phase II trial. However, although statistically not significant, bleeding events were numerically increased in atopaxar-treated patients compared with placebo. Furthermore, liver enzymes were elevated and the relative corrected QT interval was prolonged in atopaxar-treated patients. Currently, the development of atopaxar by Eisai is discontinued. The future of this novel class of antithrombotic drugs will depend on the identification of patient groups in which the risk–benefit ratio is favorable.

Inactivation of anoctamin-6/Tmem16f, a regulator of phosphatidylserine scrambling in osteoblasts, leads to decreased mineral deposition in skeletal tissues

During vertebrate skeletal development, osteoblasts produce a mineralized bone matrix by deposition of hydroxyapatite crystals in the extracellular matrix. Anoctamin6/Tmem16F (Ano6) belongs to a conserved family of transmembrane proteins with chloride channel properties. In addition, Ano6 has been linked to phosphatidylserine (PS) scrambling in the plasma membrane. During skeletogenesis, Ano6 mRNA is expressed in differentiating and mature osteoblasts. Deletion of Ano6 in mice results in reduced skeleton size and skeletal deformities. Molecular analysis revealed that chondrocyte and osteoblast differentiation are not disturbed. However, mutant mice display increased regions of nonmineralized, Ibsp-expressing osteoblasts in the periosteum during embryonic development and increased areas of uncalcified osteoid postnatally. In primary Ano6(-/-) osteoblasts, mineralization is delayed, indicating a cell autonomous function of Ano6. Furthermore, we demonstrate that calcium-dependent PS scrambling is impaired in osteoblasts. Our study is the first to our knowledge to reveal the requirement of Ano6 in PS scrambling in osteoblasts, supporting a function of PS exposure in the deposition of hydroxyapatite.

The molecular basis of leukocyte recruitment and its deficiencies

The innate immune system responds to inflammation, infection and injury by recruiting neutrophils and other leukocytes. These cells are able to leave the intravascular compartment in a process called leukocyte recruitment. This process involves several distinct steps: selectin-mediated rolling, firm adhesion via integrins, postarrest modifications including adhesion strengthening and leukocyte crawling and finally transmigration into tissue. Genetic defects affecting the different steps of the cascade can result in severe impairment in leukocyte recruitment. So far, three leukocyte adhesion deficiencies (LAD I-III) have been described in humans. These LADs are rare autosomal recessive inherited disorders and, although clinically distinct, exhibit several common features including recurrent bacterial infections and leukocytosis. In LAD-I, mutations within the β2-integrin gene result in a severe defect in β2 integrin-mediated firm leukocyte adhesion. Defects in the posttranslational fucosylation of selectin ligands dramatically reduce leukocyte rolling and lead to LAD-II. Finally, LAD-III, also known as LAD-I variant, is caused by impaired integrin activation due to mutations within the kindlin-3 gene. This review provides an overview on the molecular basis of leukocyte adhesion and its deficiencies.

Microsupport with Two-Dimensional Geometry (2D-MS)

CHO-K1 and VERO cells have been grown on MicroHextrade mark, a polystyrene-based microsupport with two-dimensional geometry and the consistency of their growth kinetics were established. These cells have been detached by exposure to buffered ethylenediaminetetraacetic acid (EDTA) followed by controlled mechanical shear to yield well-isolated cells suspended in EDTA. Neutralisation of the EDTA followed by restoration of the chemical composition of the growth medium causes detached CHO-K1 cells to display unaltered growth kinetics.

Bral2 is indispensable for the proper localization of brevican and the structural integrity of the perineuronal net in the brainstem and cerebellum

Perineuronal nets (PNNs) are pericellular coats of condensed matrix that enwrap the cell bodies and dendrites of many adult central nervous system (CNS) neurons. These extracellular matrices (ECMs) play a structural role as well as instructive roles in the control of CNS plasticity and the termination of critical periods. The cartilage link protein Crtl1/Hapln1 was reported to be a trigger for the formation of PNNs in the visual cortex. Bral2/Hapln4 is another link protein that is expressed in PNNs, mainly in the brainstem and cerebellum. To assess the role of Bral2 in PNN formation, we examined the expression of PNN components in targeted mouse mutants lacking Bral2. We show here that Bral2-deficient mice have attenuated PNNs, but the overall levels of chondroitin sulfate proteoglycans, lecticans, are unchanged with the exception of neurocan. Bral2 deficiency markedly affected the localization of brevican in all of the nuclei tested, and neurocan concomitant with Crtl1 in some of the nuclei, whereas no effect was seen on aggrecan even with the attenuation of Crtl1. Bral2 may have a role in the organization of the PNN, in association with brevican, that is independent of aggrecan binding. There was a heterogenous attenuation of PNN components, including glycosaminoglycans, indicating the elaborate molecular organization of the PNN components. Strikingly, a slight decrease in the number of synapses in deep cerebellar nuclei neurons was found. Taken together, these results imply that Bral2-brevican interaction may play a key role in synaptic stabilization and the structural integrity of the PNN.

[Rivaroxaban in the prevention and treatment of thromboembolic disorders]

Rivaroxaban (Xarelto(®)) is a new anticoagulant for the prevention and treatment of thromboembolic disorders. Rivaroxaban inhibits coagulation factor Xa directly, has high oral bioavailability, shows low propensity for drug-drug interactions and requires no routine coagulation monitoring. In patients undergoing elective knee or hip replacement surgery rivaroxaban (10 mg/d) is highly effective to prevent venous thromboembolism. In patients with non-valvular atrial fibrillation rivaroxaban (20 mg/d) has been approved to prevent stroke or systemic embolism. The favourable benefit-risk profile of rivaroxaban in the treatment of deep vein thrombosis (DVT) was shown in EINSTEIN-DVT and led to its clinical approval (twice daily 15 mg for 3 weeks, followed by 20 mg/d). Based on ATLAS-ACS-TIMI-51 which has shown that rivaroxaban (2.5 mg twice daily) reduced thrombotic cardiovascular events and mortality in patients with a recent acute coronary syndrome, the approval of low dose rivaroxaban has been submitted for this indication. Taken together, rivaroxaban may become an effective alternative to standard anticoagulants in the prevention and treatment of thromboembolic disorders.

Distinct roles for talin-1 and kindlin-3 in LFA-1 extension and affinity regulation

In inflammation, neutrophils and other leukocytes roll along the microvascular endothelium before arresting and transmigrating into inflamed tissues. Arrest requires conformational activation of the integrin lymphocyte function-associated antigen-1 (LFA-1). Mutations of the FERMT3 gene encoding kindlin-3 underlie the human immune deficiency known as leukocyte adhesion deficiency-III. Both kindlin-3 and talin-1, another FERM domain-containing cytoskeletal protein, are required for integrin activation, but their individual roles in the induction of specific integrin conformers are unclear. Here, we induce differential LFA-1 activation in neutrophils through engagement of the selectin ligand P-selectin glycoprotein ligand-1 or the chemokine receptor CXCR2. We find that talin-1 is required for inducing LFA-1 extension, which corresponds to intermediate affinity and induces neutrophil slow rolling, whereas both talin-1 and kindlin-3 are required for induction of the high-affinity conformation of LFA-1 with an open headpiece, which results in neutrophil arrest. In vivo, both slow rolling and arrest are defective in talin-1-deficient neutrophils, whereas only arrest is defective in kindlin-3-deficient neutrophils. We conclude that talin-1 and kindlin-3 serve distinct functions in LFA-1 activation.

The GTPase ARFRP1 controls the lipidation of chylomicrons in the Golgi of the intestinal epithelium

The uptake and processing of dietary lipids by the small intestine is a multistep process that involves several steps including vesicular and protein transport. The GTPase ADP-ribosylation factor-related protein 1 (ARFRP1) controls the ARF-like 1 (ARL1)-mediated Golgi recruitment of GRIP domain proteins which in turn bind several Rab-GTPases. Here, we describe the essential role of ARFRP1 and its interaction with Rab2 in the assembly and lipidation of chylomicrons in the intestinal epithelium. Mice lacking Arfrp1 specifically in the intestine (Arfrp1^vil−/−) exhibit an early post-natal growth retardation with reduced plasma triacylglycerol and free fatty acid concentrations. Arfrp1^vil−/− enterocytes as well as Arfrp1 mRNA depleted Caco-2 cells absorbed fatty acids normally but secreted chylomicrons with a markedly reduced triacylglycerol content. In addition, the release of apolipoprotein A-I (ApoA-I) was dramatically decreased, and ApoA-I accumulated in the Arfrp1^vil−/− epithelium, where it predominantly co-localized with Rab2. The release of chylomicrons from Caco-2 was markedly reduced after the suppression of Rab2, ARL1 and Golgin-245. Thus, the GTPase ARFRP1 and its downstream proteins are required for the lipidation of chylo­microns and the assembly of ApoA-I to these particles in the Golgi of intestinal epithelial cells.