Tanja Falter

Depression and cognitive deficits as long‐term consequences of thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is an acute life‐threatening microangiopathy with a tendency of relapse characterized by consumptive thrombocytopenia, microangiopathic hemolytic anemia, and spontaneous von Willebrand factor–induced platelet clumping leading to microthrombi. The brain is frequently affected by microthrombi leading to neurologic abnormalities of varying severity.

Complement C5 but not C3 is expendable for tissue factor activation by cofactor-independent antiphospholipid antibodies

The complement and coagulation cascades interact at multiple levels in thrombosis and inflammatory diseases. In venous thrombosis, complement factor 3 (C3) is crucial for platelet and tissue factor (TF) procoagulant activation dependent on protein disulfide isomerase (PDI). Furthermore, C5 selectively contributes to the exposure of leukocyte procoagulant phosphatidylserine (PS), which is a prerequisite for rapid activation of monocyte TF and fibrin formation in thrombosis. Here, we show that monoclonal cofactor-independent antiphospholipid antibodies (aPLs) rapidly activate TF on myelomonocytic cells. TF activation is blocked by PDI inhibitor and an anti-TF antibody interfering with PDI binding to TF, and requires C3 but unexpectedly not C5. Other prothrombotic, complement-fixing antibodies, for example, antithymocyte globulin, typically induce TF activation dependent on C5b-7-mediated PS exposure on the outer membrane of monocytes. We show that aPLs directly induce procoagulant PS exposure independent of C5. Accordingly, mice deficient in C3, but not mice deficient in C5, are protected from in vivo thrombus formation induced by cofactor-independent aPLs. Only immunoglobulin G (IgG) fractions with cofactor-independent anticardiolipin reactivity from patients with antiphospholipid syndrome (APS) induce complement-independent monocyte PS exposure and PDI-dependent TF activation. Neither a human monoclonal aPL directed against β2-glycoprotein I (β2GPI) nor patient IgG with selective reactivity to β2GPI rapidly activated monocyte TF. These results indicate that inhibitors of PDI and TF, but not necessarily clinically available drugs targeting C5, have therapeutic benefit in preventing thrombosis associated with APS caused by pathogenic aPLs primarily reactive with lipid, independent of β2GPI.

Retrospective pilot study for analysis of antidepressant serum concentrations of citalopram and venlafaxine during inflammation.

INTRODUCTION Inflammation-mediated changes in drug metabolism may increase drug levels in blood and lead to intoxications. The objective of this study was to find out whether elevated serum levels of C-reactive protein (CRP) are associated with increased serum concentrations of the antidepressants citalopram and venlafaxine. METHODS Therapeutic drug monitoring request forms of psychiatric patients were screened retrospectively. The serum concentrations in relation to the daily doses [(C/D) (ng/ml/mg)] and the metabolic ratios (metabolite/drug) were compared intraindividually under normal (<5 mg/l) and pathological (>5 mg/l) condition by the Wilcoxon signed-rank test. RESULTS Elevated levels of CRP were not associated with a significant (P>0.05) increase in C/D for citalopram (2.4 ng/ml/mg vs. 2.85 ng/ml/mg, N=15) or in C/D for the active moiety of venlafaxine (1.76 ng/ml/mg vs. 1.68 ng/ml/mg, N=39), compared with normal CRP serum levels. No significant difference in the metabolic ratio was observed in both groups. DISCUSSION There was no major effect of inflammation on the metabolism of citalopram and venlafaxine. Because of the broad therapeutic indices of these 2 drugs, the drugs seem to be a good choice for the treatment of depression, even if an infection occurs.

Prevalence and type of potential pharmacokinetic drug- drug interactions in old aged psychiatric patients

Purpose: The number of prescribed drugs increases with age, and resulting polypharmacy bears the risk of drug-drug interactions (DDI). We assessed the prevalence and type of cytochrome P450 (CYP) associated pharmacokinetic DDI that were considered as clinically relevant in elderly psychiatric patients under conditions of every day pharmacotherapy. Methods: For retrospective analysis a large therapeutic drug monitoring (TDM) data base was used. Patients included were elderly in- and outpatients, aged ≥ 65 years with a psychiatric disorder for whom serum level measurements of a psychotropic drug had been requested. Medication data were examined for co-prescription of clinically relevant CYP inhibitors or inducers and drugs that are substrates of these enzymes (victim drugs). Results: Data from 1243 patients (65.3% female) with a mean (± standard deviation) age of 73 ± 6 years were available for analysis. Mean number of prescribed drugs was 5.3 ± 3.4 per patient. Moderate (n=189, 73.8%) or strong (n=67, 26.2%) CYP inhibitors or inducers were prescribed in 18.9% of all patients. Most frequently prescribed CYP inhibitors were duloxetine (CYP2D6 inhibitor, n=73, 31.7%), melperone (CYP2D6 inhibitor, n=63, 27.4%) and omeprazole (CYP2C19 inhibitor, n=20, 8.7%). Carbamazepine was the most commonly prescribed CYP inducer (primarily CYP3A4 inducer, n=25, 96.2%). Taken inhibitory, inducing and substrate properties of combined drugs together, CYP-mediated DDI considered as clinically relevant could be detected in 133 (10.7%) of included patients. Conclusions: CYP-mediated DDI are common among elderly psychiatric patients. To avoid potentially supra- or sub-therapeutic concentrations of victim drugs, physicians should be more aware of these preventable interactions and adjust the dose.

Relapse Rate in Survivors of Acute Autoimmune Thrombotic Thrombocytopenic Purpura Treated with or without Rituximab

Background  Autoimmune thrombotic thrombocytopenic purpura (iTTP) is caused by autoantibody-mediated severe a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13 (ADAMTS13) deficiency leading to micro-angiopathic haemolytic anaemia (MAHA) and thrombocytopenia with organ damage. Patients survive with plasma exchange (PEX), fresh frozen plasma replacement and corticosteroid treatment. Anti-CD20 monoclonal antibody rituximab is increasingly used in patients resistant to conventional PEX or relapsing after an acute bout. Objective  This retrospective observational study focused on the relapse rate and possible influencing factors including treatment with rituximab first introduced in 2003. Patients and Methods  Seventy patients treated between January 2003 and November 2014 were evaluated. Number, duration, clinical manifestations, laboratory data and treatment of acute episodes were documented. Diagnostic criteria of acute iTTP were thrombocytopenia, MAHA, increased lactate dehydrogenase and severe ADAMTS13 deficiency. Results  Fifty-four female and 16 male patients had a total of 224 acute episodes over a median observation period of 8.3 years. The relapse rate was 2.6% per month, for women 2.4% and for men 3.5% per month. Since 2003, 17 patients with a first iTTP episode were treated with rituximab, whereas 28 were not. There was a trend towards lower relapse rates after rituximab treatment over the ensuing years. However, this was statistically not significant. Conclusion  This analysis does not show a significant reduction of acute iTTP relapses by rituximab given during an acute bout. Initial episodes are characterized by more severe clinical signs compared with the less severe relapses. Furthermore, men suffer significantly more frequent and considerably more serious acute relapses.

BDNF Plasma Levels and BDNF Exon IV Promoter Methylation as Predictors for Antidepressant Treatment Response

Major problems of current antidepressant pharmacotherapy are insufficient response rates and difficulties in response prediction. We recently provided preliminary evidence in a small study that patients with major depressive disorder (MDD) with a hypomethylation of the CpG-87 site of the promoter IV region of the brain-derived neurotrophic factor (BDNF) gene are less likely to benefit from antidepressants. Here, we aimed at replicating this finding in a secondary analysis of 561 MDD patients (mean age 40.0 ± 11.9 years, 56% female) included into the Early Medication Change study (EMC). We measured BDNF exon IV promoter and p11 gene methylation at Baseline (BL) as well as BDNF-plasma-levels (pBDNF) at BL and day 14 and related them to treatment outcome. Although we were not able to replicate the predictor function of hypomethylation of the BDNF exon IV promoter, a subgroup of patients with severe depression (Hamilton Depression Rating Scale [HAMD-17] ≥ 25) (n = 199) and hypermethylation at CpG-87 of the BDNF exon IV promoter had significantly higher remission rates than patients without a methylation (p = 0.032). We also found that 421 (75%) of 561 patients showed an early improvement (≥ 20% HAMD-17 reduction after 2 weeks), which was associated with a 4.24-fold increased likelihood to remit at study end compared to the 140 patients without early improvement. However, specificity of response prediction of early improvement was low (34%) and false positive rate high (66%). The combination of early improvement with a pBDNF increase between BL and day 14, however, increased the specificity of response prediction from 34 to 76%, and the combination with methylation of the CpG-87 site of the BDNF exon IV promoter from 34 to 62%. Thus, the combined markers reduced false positives rates from 66 to 24% and 38%, respectively. Methylation at other sites or p11 promoter methylation failed to increase specificity of early improvement prediction. In sum, the results add to previous findings that BDNF, BDNF promoter methylation and the combination of clinical and biological markers may be interesting candidates for therapy response prediction which has to be confirmed in further studies. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT00974155, identifier: NCT00974155

Gerinnungsdiagnostik – Hämostasestörungen erkennen

Die Gerinnungsdiagnostik wird zunehmend wichtiger. Sie wird gebraucht zur Abklarung von Blutungs- und Thromboseneigungen, Synthesestorungen, zur perioperativen Pravention sowie zur Kontrolle der Therapie mit gerinnungsaktiven Medikamenten und Antikoagulanzien. Der Artikel soll dazu dienen, die komplexen Blutungs- und Thrombose-Erkrankungen zu verstehen und den Umgang mit ihnen zu erleichtern. Dabei erfahren Sie auch, welche Laboruntersuchungen fur die verschiedenen Erkrankungen infrage kommen.