The myelin-associated glycoprotein inhibitor BENZ induces outgrowth and survival of rat dorsal root ganglion cell cultures

The novel myelin-associated glycoprotein (MAG) inhibitor BENZ binds to the N-acetylneuraminic acid (Neu5Ac) portion of the N-terminal Ig-like domain of MAG. Treatment of rat dorsal root ganglion (DRG) cell cultures with BENZ-induced outgrowth of neurofilament 200-positive neurites improved survival of neurons and increased the number of GFAP-positive cells, as determined by fluorescence and confocal laser microscopy and by Western immunoblotting. Furthermore, treatment of DRG cell cultures with BENZ repressed gene and protein expression of the small GTPase RhoA but induced expression of Rho GTP-activating proteins 5 and 24, likely to counteract protein kinase A activity. Specifically, expression of inhibitors of neurite outgrowth, for example, Rock2 and PAK4, was repressed, but cofilin 1, a promoter of axonal growth, was induced. We propose that the MAG inhibitor BENZ abrogates the RhoA-ROCK-cofilin pathway to promote neurite outgrowth. Our findings require confirmation by in vivo animal studies.     

Blockage of VIP during mouse embryogenesis modifies adult behavior and results in permanent changes in brain chemistry

Vasoactive intestinal peptide (VIP) regulates growth and development during the early postimplantation period of mouse embryogenesis. Blockage of VIP with a VIP antagonist during this period results in growth restriction, microcephaly, and developmental delays. Similar treatment of neonatal rodents also causes developmental delays and impaired diurnal rhythms, and the adult brains of these animals exhibit neuronal dystrophy and increased VIP binding. These data suggest that blockage of VIP during the development of the nervous system can result in permanent changes to the brain. In the current study, pregnant mice were treated with a VIP antagonist during embryonic days 8 through 10. The adult male offspring were examined in tests of novelty, paired activity, and social recognition. Brain tissue was examined for several measures of chemistry and gene expression of VIP and related compounds. Glial cells from the cortex of freated newborn mice were plated with neurons and examined for VIP binding and their ability to enhance neuronal survival. Treated adult male mice exhibited increased anxiety-like behavior and deficits in social behavior. Brain tissue exhibited regionally specific changes in VIP chemistry and a trend toward increased gene expression of VIP and related compounds that reached statistical significance in the VIP receptor, VPAC-1, in the female cortex. When compared to control astrocytes, astrocytes from treated cerebral cortex produced further increases in neuronal survival with excess synaptic connections and reduced VIP binding. In conclusion, impaired VIP activity during mouse embryogenesis resulted in permanent changes to both adult brain chemistry/cell biology and behavior with aspects of autism-like social deficits.     

Screening of amide analogues of Trichostatin A in cultures of primary rat hepatocytes: search for potent and safe HDAC inhibitors

Summary  The vast majority of preclinical studies of HDAC inhibitors (HDAC-I) focus on the drug–target (cancer) cell interaction, whereas little attention is paid to the effects on non-target healthy cells, which could provide decisive information to eliminate potential cytotoxic compounds at a very early stage during drug development. In the current study we used cultures of primary rat hepatocytes as a read out system to select for the most potent HDAC-I in the group of structural analogues of an archetypal HDAC-I, namely Trichostatin A. This kind of approach allowed selecting compounds with high biological activity and with no apparent toxicity towards cultured hepatocytes. Joanna Fraczek and Sarah Deleu contributed equally to this article. T. Vanhaecke is a postdoctoral research fellow of the Fund for Scientific Research Flanders (FWO-Vlaanderen, Belgium)     

Development of water soluble derivatives of <Emphasis Type="Italic">cis</Emphasis>-3, 4′, 5-trimethoxy-3′-aminostilbene for optimization and use in cancer therapy

Summary  Colchicine site tubulin inhibitors are currently developed as vascular disrupting agents (VDAs). However, they were found to have cardiotoxicity in clinical trials. To overcome the problem, we developed a stilbene derivative, cis-3, 4′, 5-trimethoxy-3′-aminostilbene (stilbene 5c), which is highly potent and has no bone marrow and cardiac toxicity in mice. Here we attempt to optimize stilbene 5c using computer-based drug design and synthesize derivatives with benzimidazole or indole group. Biological evaluation showed that they are weaker than stilbene 5c without better water solubility. Alternative approach was thus adopted to make prodrugs of stilbene 5c. A water-soluble prodrug PD7 was synthesized by addition of a morpholino group with carbamate linkage to the amino group of stilbene 5c. In vitro studies show that PD7 induces mitotic arrest and disrupts microtubule similar to stilbene 5c. The cell signaling events in Cdc2, p53, Akt, and aurora kinase are similar in cells treated with stilbene 5c, CA4 or PD7, suggesting that they share the same mechanism. Although PD7 is less effective than stilbene 5c in vitro, the biological activity of PD7 as a single agent is similar to that of stilbene 5c. Combination of PD7 with VEGF inhibitor bevacizumab significantly enhances the therapeutic efficacy of PD7 in mouse xenograft model. These data suggest that PD7 could be a good candidate for further pre-clinical and clinical development as a new VDA for cancer therapy.     

Role of NT-proBNP and 6MWD in chronic thromboembolic pulmonary hypertension

BACKGROUND: This study aims to evaluate the role of NT-proBNP and six minute walking distance (6MWD) in the pre- and post-operative assessment of subjects undergoing pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH). METHODS: Subjects undergoing PEA between August 2004 and July 2006 were assessed at baseline and 3 months post-operatively with resting haemodynamics, NT-proBNP and 6MWD. RESULTS: A number of 111 subjects underwent surgery, of which 102 were included. 15 subjects died before their 3 month assessment. Non-survivors had significantly worse preoperative NT-proBNP and 6MWD (4728 pg/mL vs 1863 pg/mL, p=0.001, 182.4 m vs 263.5 m, p=0.001). Taking pre-operative cut-off values of 1200 pg/mL for NT-proBNP and 345 m for 6MWD, both tests had high negative predictive value for predicting mortality (97.3% and 100%, respectively). Amongst survivors, peri-operative changes in NT-proBNP and 6MWD correlated with changes in total pulmonary resistance (TPR) (r=0.49, p<0.001 and r=-0.46, p<0.001). Post-operatively, both NT-proBNP and 6MWD also correlated with mPAP (r=0.65, p<0.001 and r=-0.50, p<0.001) and PVR (r=0.63, p<0.001 and r=-0.47, p<0.001). The ability of NT-proBNP to predict persistent pulmonary hypertension was significantly confounded by age, but not gender, BMI or renal function. CONCLUSIONS: Pre-operative evaluation with NT-proBNP and 6MWD helps risk-stratify patients prior to PEA. Post-operatively, both markers correlate with changes in disease burden and right ventricular function. These results suggest that both NT-proBNP and 6MWD offer effective 'bedside' tools for the long term follow up of patients with CTEPH.     

Serum concentration of visfatin in obese women

The aim of the present study was to determine serum concentrations of visfatin in obese women in comparison to normal-weight controls. Study subjects were 21 obese women without additional disease (age, 29.0+/-4.9 years; body mass index, 37.1+/-6.1 kg/m2) and 16 healthy, normal-weight women (age, 29.9+/-5.4 years; body mass index, 22.5+/-1.7 kg/m2). Body composition was measured by bioimpedance. Serum concentrations of visfatin were assayed with an enzyme-linked immunosorbent assay kit (Phoenix Pharmaceuticals, Burlingame, CA). Insulin was determined by radioimmunoassay and glucose by colorimetric method. Serum concentration of visfatin was significantly higher in obese women when compared to controls. Positive correlations between serum concentrations of visfatin and insulin in the obese group were found. In the control group, we observed positive correlations between serum concentrations of visfatin and glucose. In conclusion, the observed increase of visfatin in obesity may be a counterregulation preventing further glucose increase.