Comparative Studies of Superoxide Production by Microbial Wall Product-Primed Neutrophils in Ulcerative Colitis

A diminished tolerance to the normal gut bacterial flora has been suggested to be pathogenic in ulcerative colitis (UC) and the aim of this study was to evaluate the priming effect of selected bacterial wall products on UC neutrophil granulocytes. Neutrophils from 10 UC patients and 10 healthy controls were primed with bacterial lipoprotein (BLP) or lipopolysaccharide (LPS) and subsequently activated. Extracellular superoxide production was measured by the cytochrome c reduction assay. Priming neutrophils with BLP or LPS dose dependently increased the superoxide production in both UC and controls (P < 0.01), and BLP was more potent than LPS (P < 0.05). No differences were found between UC and controls. UC neutrophils do not seem to have an intrinsic abnormality with reduced tolerance to bacterial substances. However, bacterial wall products such as BLP modify neutrophil tissue-destruction mechanisms and might be pivotal for perpetuation of chronic colonic inflammation.     

Clopidogrel in acute coronary syndrome: when, how much, how long?

An important part of the therapy management of acute coronary syndrome (ACS) consists of antiplatelet drugs. Whereas the administration of acetylsalicylic acid (ASA) is well established, the guidelines recommend the additive use of clopidogrel in patients with ACS without persisting ST-elevation. Clopidogrel should be added to ASA as soon as possible in patients with a non-invasive treatment strategy and continued for more than 1 month (class 1A) and up to 9 months (class 1B). In patients for whom a percutaneous coronary intervention (PCI) is planned, an additional loading-dose of 300 mg clopidogrel should be given on top of ASA (100 mg).These recommendations are based on data recently published in the CURE and CREDO trials, which however should be critically discussed: In these trials, an absolute risk reduction of only 2% could be documented by additive use of clopidogrel. The combined endpoint of cardiovascular death, myocardial infarction and stroke is significantly reduced, but there was no improvement taken the individual endpoints alone. In additional, the data for duration of clopidogrel therapy were determined by taken the mean follow-up of these studies. The efficacy of the dual antiplatelet therapy should be discussed in the context of an increased frequency of major bleedings (in total 1%) and should be considered against a reasonable cost effective background.     

Orale Thrombozytenhemmung in der primären und sekundären Prävention

Cardiovascular disease is the leading cause of death in western societies, with further increasing incidence. Therefore both, primary and secondary prevention play a pivotal role. Medicamentous prevention schemes include the antithrombotic drugs acetylsalicylic acid (ASS) and clopidogrel. A number of studies tested the efficacy and safety of ASS for primary prevention. A meta-analysis of these primary prevention trials could demonstrate a decrease of cardiovascular events only for patients being at high cardiovascular risk. However, since ASS does not influence the mortality but is significantly increasing the risk for bleeding, careful risk stratification is indispensable prior to preventive chronic administration of the drug. Therapy with ASS in the secondary prevention is commonly accepted and clearly evidence-based given that a meta-analysis of 145 trials could demonstrate a significant decrease in mortality. A daily dose of 100 mg has been shown to achieve sufficient antithrombotic effects with an acceptable rate of side effects. Clopidogrel is currently not used for primary prevention, since evidence is lacking and the costs are high. For secondary prevention after acute coronary syndromes, a decrease of cardiovascular events could be demonstrated for clopidogrel. This benefit was especially pronounced after percutaneous coronary interventions. However, clopidogrel could not decrease the mortality. Therefore, long-term treatment with clopidogrel in the secondary prevention should be based on a critical appraisal of risk and benefit on the one hand and socioeconomic aspects on the other hand.     

Novel Mutations in the DYNC1H1 Tail Domain Refine the Genetic and Clinical Spectrum of Dyneinopathies

The heavy chain 1 of cytoplasmic dynein (DYNC1H1) is responsible for movement of the motor complex along microtubules and recruitment of dynein components. Mutations in DYNC1H1 are associated with spinal muscular atrophy (SMA), hereditary motor and sensory neuropathy (HMSN), cortical malformations, or a combination of these. Combining linkage analysis and whole‐exome sequencing, we identified a novel dominant defect in the DYNC1H1 tail domain (c.1792C>T, p.Arg598Cys) causing axonal HMSN. Mutation analysis of the tail region in 355 patients identified a de novo mutation (c.791G>T, p.Arg264Leu) in an isolated SMA patient. Her phenotype was more severe than previously described, characterized by multiple congenital contractures and delayed motor milestones, without brain malformations. The mutations in DYNC1H1 increase the interaction with its adaptor BICD2. This relates to previous studies on BICD2 mutations causing a highly similar phenotype. Our findings broaden the genetic heterogeneity and refine the clinical spectrum of DYNC1H1, and have implications for molecular diagnostics of motor neuron diseases.     

Dose- and time-dependent gene expression alterations in prostate and colon cancer cells after in vitro exposure to carbon ion and X-irradiation

Hadrontherapy is an advanced form of radiotherapy that uses beams of charged particles (such as protons and carbon ions). Compared with conventional radiotherapy, the main advantages of carbon ion therapy are the precise absorbed dose localization, along with an increased relative biological effectiveness (RBE). This high ballistic accuracy of particle beams deposits the maximal dose to the tumor, while damage to the surrounding healthy tissue is limited. Currently, hadrontherapy is being used for the treatment of specific types of cancer. Previous in vitro studies have shown that, under certain circumstances, exposure to charged particles may inhibit cell motility and migration. In the present study, we investigated the expression of four motility-related genes in prostate (PC3) and colon (Caco-2) cancer cell lines after exposure to different radiation types. Cells were irradiated with various absorbed doses (0, 0.5 and 2 Gy) of accelerated ¹³C-ions at the GANIL facility (Caen, France) or with X-rays. Clonogenic assays were performed to determine the RBE. RT-qPCR analysis showed dose- and time-dependent changes in the expression of CCDC88A, FN1, MYH9 and ROCK1 in both cell lines. However, whereas in PC3 cells the response to carbon ion irradiation was enhanced compared with X-irradiation, the effect was the opposite in Caco-2 cells, indicating cell-type–specific responses to the different radiation types.     

Contribution of Colonic Fermentation and Fecal Water Toxicity to the Pathophysiology of Lactose-Intolerance

Whether or not abdominal symptoms occur in subjects with small intestinal lactose malabsorption might depend on differences in colonic fermentation. To evaluate this hypothesis, we collected fecal samples from subjects with lactose malabsorption with abdominal complaints (LM-IT, n = 11) and without abdominal complaints (LM-T, n = 8) and subjects with normal lactose digestion (NLD, n = 15). Lactose malabsorption was diagnosed using a ¹³C-lactose breath test. Colonic fermentation was characterized in fecal samples at baseline and after incubation with lactose for 3 h, 6 h and 24 h through a metabolomics approach using gas chromatography-mass spectrometry (GC-MS). Fecal water cytotoxicity was analyzed using a colorimetric assay. Fecal water cytotoxicity was not different between the three groups (Kruskall-Wallis p = 0.164). Cluster analysis of the metabolite patterns revealed separate clusters for NLD, LM-T and LM-IT samples at baseline and after 24 h incubation with lactose. Levels of 5-methyl-2-furancarboxaldehyde were significantly higher in LM-IT and LM-T compared to NLD whereas those of an unidentified aldehyde were significantly higher in LM-IT compared to LM-T and NLD. Incubation with lactose increased short chain fatty acid (SCFA) concentrations more in LM-IT and LM-T compared to NLD. In conclusion, fermentation patterns were clearly different in NLD, LM-IT and LM-T, but not related to differences in fecal water cytotoxicity.