Precision-cut liver slices as a new model to study toxicity-induced hepatic stellate cell activation in a physiologic milieu.

Hepatic stellate cell (HSC) activation is a key event in the natural process of wound healing as well as in fibrosis development in liver. Current in vitro models for HSC activation contribute significantly to the understanding of HSC biology and fibrogenesis but still fall far short of recapitulating in vivo intercellular functional and anatomic relationships. In addition, when cultured on uncoated plastic, HSC spontaneously activate, which makes HSC activation difficult to regulate or analyze. We have examined whether the use of precision-cut liver slices might overcome these limitations. Liver slices (8 mm diameter, 250 microm thickness) were generated from normal rat liver and incubated for 3 or 16 h with increasing doses of carbon tetrachloride (CCl4). Rat liver slices remained viable during incubation, as shown by minimal enzyme leakage. Expression of markers for HSC activation and the onset of fibrogenesis in the liver slices was studied using real-time PCR and Western blotting. In unstimulated liver slices, mRNA and protein levels of desmin, heat shock protein 47, and alpha B-crystallin remained constant, indicating quiescence of HSC, whereas Krüppel-like factor 6 expression was increased. In contrast, incubation with CCl4 led to a time- and dose-dependent increase in mRNA expression of all markers and an increased alpha B-crystallin protein expression. In conclusion, we have developed a technique to induce activation of quiescent HSC in rat liver slices. This model permits the study of toxicity-induced HSC activation within a physiological milieu, not only in animal but ultimately also in human tissue, and could contribute to the reduction of animal experiments.     

Albumin-protamine-oligonucleotide nanoparticles as a new antisense delivery system. Part 1: physicochemical characterization.

In this paper, a ternary system of albumin-protamine-oligonucleotide nanoparticles (AlPrO-NP) recently developed by Vogel et al. [V. Vogel, D. Lochmann, J. Weyermann, G. Mayer, C. Tziatzios, J.A. van den Broek, W. Haase, D. Wouters, U.S. Schubert, J. Kreuter, A. Zimmer, D. Schubert, Oligonucleotide-protamine-albumin nanoparticles: preparation, physical properties and intracellular processing, J. Controlled Rel. (in press)] which could serve as a potential drug delivery system for antisense oligonucleotides. Former studies of binary protamine-oligonucleotide nanoparticles showed two main disadvantages: (i) aggregation of the particles within a few minutes in the presence of salt; (ii) low intracellular dissociation between protamine and oligonucleotide, especially phosphorothioates. To overcome these problems, human serum albumin (HSA) as a non-toxic, biodegradable macromolecule was introduced as protective colloid. The assembly process of AlPrO-NP was investigated by small angle X-ray scattering (SAXS), fluorescence correlation spectroscopy (FCS), photon correlation spectroscopy (PCS) measurements and scanning electron microscopy (SEM). 'Initial complexes' of HSA and protamine sulphate with a mean hydrodynamic diameter (dh) of about 10-14 nm were found. After adding oligonucleotides (unmodified, phosphorothioate DNA and small interfering RNA), nanoparticles (NPs) were assembled in water and in isotonic media with a dh in a range of 230-320 nm for most preparations. The chemical composition of the particles was investigated by high performance liquid chromatography and fluorescence spectrometry. The whole amount of oligonucleotides (30 microg) was entrapped into the particles at a 1:2 mass ratio (oligonucleotide/protamine). Approximately 7-10% (w/w) of the HSA was bound to the particles. The surface charge of the particles ranged from about +12 to -60 mV depending on the protamine concentration and the ionic conditions. The size and the molecular weight of the components, initial complexes and two model NP preparations were calculated from FCS data. These data verified the PCS, SEM and SAXS measurements.     

The Protective Effect of Rosuvastatin on Ischemic-Brain Injury and Its Mechanism

The statins, which lower plasma cholesterol levels, are 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase inhibitors. To date, stains have developed to third generation, which include five commonly used stains: lovastatin, pravastatin, simvastatin, fluvastatin and atorvastatin. Recently, a new statin, named rosuvas-tatin, was used in the third stage of clinical trial. Rosu-vastatin, in contrast to most other statins, has the more powerful capability to lower plasma cholesterol levels,…     

Association of Paclitaxel pharmacokinetics with the development of peripheral neuropathy in patients with advanced cancer.

PURPOSE: The shortening of infusion time from 3 to 1 hour decreases the systemic exposure (area under the curve, AUC) of total and unbound paclitaxel but increases the AUC of its vehicle Cremophor EL, whereas the time above total paclitaxel concentrations of 0.05 micromol/L (T >0.05) remains almost constant. As both Cremophor EL and paclitaxel are neurotoxic, we evaluated their pharmacodynamic effects on the development of peripheral neuropathy as the most important nonhematologic toxicity. EXPERIMENTAL DESIGN: Patients with advanced cancer of different origin were randomized to receive a maximum of 12 weekly-given 1- or 3-hour infusions of 100 mg/m2 paclitaxel (Taxol). Twenty-four patients were assessable for both pharmacokinetics and peripheral neuropathy development evaluated by a clinical scoring system including sensory symptoms, strength, tendon reflexes, and vibratory sense. RESULTS: Patients with peripheral neuropathy development (n=14) received more weeks of therapy (P=0.056) and showed significantly higher T(>0.05) (P=0.022) and overall systemic drug exposures (weeks of therapy x AUC) for total paclitaxel (P=0.002) and unbound paclitaxel (P=0.003) than those without peripheral neuropathy. In Kaplan-Meier analyses, T(>0.05) > or = 10.6 hours (P=0.023), AUC of total paclitaxel > or = 4.7 microg/mL x hour (P = 0.047), and AUC of unbound paclitaxel > or = 0.375 microg/mL x hour (P = 0.095) were identified as being potential factors for peripheral neuropathy development. In a Cox regression analysis, only T(>0.05) > or = 10.6 hours remained as an independent risk factor (relative risk, 18.43; P = 0.036) after adjusting for prior vincamycin (relative risk, 11.28; P = 0.038). CONCLUSIONS: From the results obtained in this study, it is concluded that exposure to paclitaxel but not Cremophor EL is associated with peripheral neuropathy development.     

Effects of radiotherapy planning with a dedicated combined PET-CT-simulator of patients with non-small cell lung cancer on dose limiting normal tissues and radiation dose-escalation: a planning study.

BACKGROUND AND PURPOSE: To investigate the effect of radiotherapy planning with a dedicated combined PET-CT simulator of patients with locally advanced non-small cell lung cancer. PATIENTS AND METHODS: Twenty-one patients underwent a pre-treatment simulation on a dedicated hybrid PET-CT-simulator. For each patient, two 3D conformal treatment plans were made: one with a CT based PTV and one with a PET-CT based PTV, both to deliver 60Gy in 30 fractions. The maximum tolerable prescribed radiation dose for CT versus PET-CT PTV was calculated based on constraints for the lung, the oesophagus, and the spinal cord, and the Tumour Control Probability (TCP) was estimated. RESULTS: For the same toxicity levels of the lung, oesophagus and spinal cord, the dose could be increased from 55.2+/-2.0Gy with CT planning to 68.9+/-3.3Gy with the use of PET-CT (P=0.002), with corresponding TCP's of 6.3+/-1.5% for CT and 24.0+/-5.6% for PET-CT planning (P=0.01). CONCLUSIONS: The use of a combined dedicated PET-CT-simulator reduced radiation exposure of the oesophagus and the lung, and thus allowed significant radiation dose escalation whilst respecting all relevant normal tissue constraints.     

Detection of spontaneous CD4+ T-cell responses in melanoma patients against a tyrosinase-related protein-2-derived epitope identified in HLA-DRB1*0301 transgenic mice.

PURPOSE: The frequently expressed differentiation antigen tyrosinase-related protein-2 (TRP-2) has repeatedly been described as a target of spontaneous cytotoxic T-cell responses in melanoma patients, suggesting that it might be an ideal candidate antigen for T cell-based immunotherapy. As a prerequisite for immunization, T-cell epitopes have to be identified. Whereas a number of HLA class I-presented TRP-2-derived epitopes are known, information about HLA class II-presented antigenic ligands recognized by CD4+ T helper (Th) cells is limited. EXPERIMENTAL DESIGN: The search for TRP-2-derived Th epitopes was carried out by competitive in vitro peptide binding studies with predicted HLA-DRB1*0301 ligands in combination with peptide and protein immunizations of HLA-DRB1*0301 transgenic mice. In vivo selected candidate epitopes were subsequently verified for their immunogenicity in human T-cell cultures. RESULTS: This strategy led to the characterization of TRP-2(60-74) as an HLA-DRB1*0301-restricted Th epitope. Importantly, TRP-2(60-74)-reactive human CD4+ Th cell lines, specifically recognizing target cells loaded with recombinant TRP-2 protein, could be established by repeated peptide stimulation of peripheral blood lymphocytes from several HLA-DRB1*03+ melanoma patients. Even short-term peptide stimulation of patients' peripheral blood lymphocytes showed the presence of TRP-2(60-74)-reactive T cells, suggesting that these T cells were already activated in vivo. CONCLUSION: Peptide TRP-2(60-74) might be a useful tool for the improvement of immunotherapy and immune monitoring of melanoma patients.     

Dietary sodium restriction specifically potentiates left ventricular ACE inhibition by zofenopril, and is associated with attenuated hypertrophic response in rats with myocardial infarction.

INTRODUCTION: In patients with myocardial infarction (MI)-induced heart failure, angiotensin-converting enzyme (ACE) inhibitors are proven effective therapy in inhibiting the progression towards overt heart failure. However, the prognosis in these patients is still very poor, and optimisation of therapy is warranted. The antihypertensive and renoprotective effects of ACE inhibitors (ACE-Is) can be substantially enhanced by dietary sodium restriction. In line with the latter, the aim of the present study was to explore whether dietary sodium restriction enhances the efficacy of ACE-I after MI. METHODS: Rats with MI-induced left ventricular (LV) dysfunction received ACE-I therapy with zofenopril (5.5 mg/kg/day orally), with or without dietary sodium restriction. ACE activity was measured in non-infarcted LV tissue, kidneys and plasma. Effects on cardiac hypertrophy were examined by means of organ weight/body weight ratios. After blood pressure (BP) measurements, functional consequences of therapy were evaluated as LV pressure development in isolated perfused hearts. RESULTS: Dietary sodium restriction alone had no effect on any of the measured parameters, whereas zofenopril alone significantly reduced plasma and kidney ACE activity, but not LV ACE activity, nor LV weight/body weight ratio. However, only when ACE-I therapy was combined with dietary sodium restriction was LV ACE activity significantly reduced. This effect was paralleled by inhibition of LV hypertrophy. BP was reduced after infarction, and further reduced by zofenopril, but not affected by dietary sodium. Neither treatment was associated with effects on the MI-induced reduction of LV function in vitro. CONCLUSIONS: Effects of ACE inhibition with zofenopril can be potentiated by additional dietary sodium restriction. However, these effects were tissue-specific, since LV, but not kidney or plasma, ACE activity was affected by the additional dietary sodium restriction. Effects on LV ACE activity were paralleled by reduced LV hypertrophy. Since the measured parameters did not indicate any adverse side-effects, dietary sodium restriction may provide a safe strategy to improve ACE-I efficacy in patients with infarction-induced LV dysfunction.