GBS Leiden

DNA methylation profiles of aggressive behavior may capture lifetime cumulative effects of genetic, stochastic, and environmental influences associated with aggression. Here, we report the first large meta-analysis of epigenome-wide association studies (EWAS) of aggressive behavior (N = 15,324 participants). In peripheral blood samples of 14,434 participants from 18 cohorts with mean ages ranging from 7 to 68 years, 13 methylation sites were significantly associated with aggression (alpha = 1.2 × 10−7; Bonferroni correction). In cord blood samples of 2425 children from five cohorts with aggression assessed at mean ages ranging from 4 to 7 years, 83% of these sites showed the same direction of association with childhood aggression (r = 0.74, p = 0.006) but no epigenome-wide significant sites were found. Top-sites (48 at a false discovery rate of 5% in the peripheral blood meta-analysis or in a combined meta-analysis of peripheral blood and cord blood) have been associated with chemical exposures, smoking, cognition, metabolic traits, and genetic variation (mQTLs). Three genes whose expression levels were associated with top-sites were previously linked to schizophrenia and general risk tolerance. At six CpGs, DNA methylation variation in blood mirrors variation in the brain. On average 44% (range = 3–82%) of the aggression–methylation association was explained by current and former smoking and BMI. These findings point at loci that are sensitive to chemical exposures with potential implications for neuronal functions. We hope these results to be a starting point for studies leading to applications as peripheral biomarkers and to reveal causal relationships with aggression and related traits.

Treatment with the second and third generation BCR-ABL1 tyrosine kinase inhibitors (TKIs) increases cardiovascular risk in chronic myeloid leukemia (CML) patients. We investigated the vascular adverse effects of three generations of TKIs in a translational model for atherosclerosis, the APOE*3Leiden.CETP mouse. Mice were treated for sixteen weeks with imatinib (150 mg/kg BID), nilotinib (10 and 30 mg/kg QD) or ponatinib (3 and 10 mg/kg QD), giving similar drug exposures as in CML-patients. Cardiovascular risk factors were analyzed longitudinally, and histopathological analysis of atherosclerosis and transcriptome analysis of the liver was performed. Imatinib and ponatinib decreased plasma cholesterol (imatinib, −69%, p < 0.001; ponatinib 3 mg/kg, −37%, p < 0.001; ponatinib 10 mg/kg−44%, p < 0.001) and atherosclerotic lesion area (imatinib, −78%, p < 0.001; ponatinib 3 mg/kg, −52%, p = 0.002; ponatinib 10 mg/kg, −48%, p = 0.006), which were not affected by nilotinib. In addition, imatinib increased plaque stability. Gene expression and pathway analysis demonstrated that ponatinib enhanced the mRNA expression of coagulation factors of both the contact activation (intrinsic) and tissue factor (extrinsic) pathways. In line with this, ponatinib enhanced plasma levels of FVII, whereas nilotinib increased plasma FVIIa activity. While imatinib showed a beneficial cardiovascular risk profile, nilotinib and ponatinib increased the cardiovascular risk through induction of a pro-thrombotic state.

Recruitment of leukocytes is critical for controlling infections. However, chronic leukocyte activity is deleterious in a variety of pathological conditions. As such, leukocyte behavior is an attractive pharmacological target, although knowledge is lacking on the exact triggers driving leukocyte migration. We explored the contribution of coagulation pathways versus TLR4 signaling on the leukocyte recruitment by mimicking non-sterile and sterile leukocyte activation. A sterile inflammatory milieu was generated by spontaneous ex-vivo coagulation of human whole blood, a non-sterile milieu by incubating human whole blood with LPS (at the maximal effective dose), inducing TLR-4 mediated cytokines. The chemoattractant activity of supernatant obtained from these conditions was compared by assessment of primary human leukocyte recruitment in transwell cultures, microscopically and by flow cytometry. Human recombinant IL-8 (100 ng/mL) was used as control chemoattractant. Ex-vivo coagulation resulted in a strong release of IL-8 (119±58 ng/mL), being 5-fold higher than LPS-induced IL-8 release. Leukocyte recruitment (mainly identified as granulocytes) towards the sterile milieu was greater than TLR4-driven chemoattraction. Comparison of recombinant IL-8-induced and coagulation-induced chemotaxis indicated that chemotaxis towards the coagulated milieu was driven by more factors than IL-8 alone. Additional experiments indicated that fibrinogen cleavage product fibrinopeptide B may be involved, as this dose-dependently increased leukocyte migration. Coagulation activation drives substantial neutrophil recruitment, primarily mediated by IL-8. For this ex-vivo coagulation model, a stronger and differently mediated leukocyte response was observed compared to TLR4-driven chemoattraction. The model can be used to study the involvement of extracellular coagulation pathways in specific inflammatory pathways that differ distinctly from pathways involved in non-sterile inflammatory conditions. This model, when further optimized, may be helpful as a methodological tool for early evaluation of new treatment modalities for chronic inflammatory diseases.

There is no clear consensus about tests in vitro that are suitable for evaluating various factor Xa inhibitors. The availability of reversible and irreversible inhibitors further complicates the application of available assays. We evaluated the suitability of the prothrombinase-induced clotting test (PiCT) for fondaparinux and rivaroxaban, as representatives for irreversible and reversible inhibition of factor Xa, with specific attention to preincubation times prior to re-calcification, in the context of automate program limitations. We demonstrate that the PiCT assay requires a preincubation step to allow inhibitory activity by fondaparinux. Without this step, inhibition in the test is minimal and lacking sufficient dynamic range. In contrast, to measure the reversible inhibition by rivaroxaban, we found any preincubation introduced an artifact in inhibition as exemplified by a biphasic pattern and only the test without a preincubation phase gave informative results. It is concluded that PiCT in its format with two steps is suitable for fondaparinux evaluation, while its format without preincubation (the one-addition format) is suitable for reversible inhibitors such as rivaroxaban. Unfortunately, both types of inhibitors cannot be compared in vitro in a single assay format.