Nocifensive Behaviors in Mice with Radiation-Induced Oral Mucositis.

Oral mucositis can result in significant dysphagia, and is the most common dose-limiting acute toxicity in head and neck cancer patients receiving chemoradiotherapy. There is a critical need to determine the cellular and molecular mechanisms that underlie radiotherapy-associated discomfort in patients with mucositis. The objective was to induce oral mucositis in mice, using a clinical linear accelerator, and to quantify resultant discomfort, and characterize peripheral sensitization. A clinical linear accelerator was used to deliver ionizing radiation to the oral cavity of mice. Mucositis severity scoring, and various behavioral assays were performed to quantify bouts of orofacial wiping and scratching, bite force, gnawing behavior and burrowing activity. Calcium imaging was performed on neurons of the trigeminal ganglia. Glossitis was induced with a single fraction of at least 27 Gy. Body weight decreased and subsequently returned to baseline, in concert with development and resolution of mucositis, which was worst at day 10 and 11 postirradiation, however was resolved within another 10 days. Neither bite force, nor gnawing behavior were measurably affected. However, burrowing activity was decreased, and both facial wiping and scratching were increased while mice had visible mucositis lesions. Sensory nerves of irradiated mice were more responsive to histamine, tumor necrosis factor alpha and capsaicin. Radiation-induced glossitis is associated with hyper-reactivity of sensory neurons in the trigeminal ganglia of mice, and is accompanied by several behaviors indicative of both itch and pain. These data validate an appropriate model for cancer treatment related discomfort in humans.

Pathogenetic and therapeutic implications of the histamine H4 receptor in inflammatory skin diseases and pruritus.

Chronic inflammatory skin diseases such as atopic dermatitis (AD) are clinically characterized by erythematous and pruritic skin lesions, immunologically mediated by an inflammatory infiltrate consisting of T-cells, antigen presenting cells (APC) and eosinophilic granulocytes. Histamine levels are increased in lesions of inflammatory skin diseases. It is likely that histamine also plays a pathogenetic role since various relevant cell types such as T-cells and APC express functional histamine receptors. However, therapeutic blockade of the histamine H1 and H2 receptor is inefficient at least in the treatment of atopic dermatitis. We summarize here current data on the role of the recently described histamine H4 receptor (H4R) in chronic inflammatory skin diseases. The H4R is functionally expressed on relevant cell types such as T-cells, APC and keratinocytes. In murine models of contact hypersensitivity and pruritus, H4R blockade had significant in vivo effects. Taken together, several lines of evidence suggest a role of the H4R in chronic inflammatory skin disease and the H4R might be a therapeutic target for diseases such as AD.

A fast and flexible PEG-mediated transient expression system in plants for high level expression of secreted recombinant proteins.

Plant expression systems offer a valuable alternative to traditional systems for the production of recombinant biopharmaceuticals. A highly efficient polyethyleneglycol (PEG)-mediated transient expression system for secreted recombinant proteins in plants has been developed. The human vascular endothelial growth factor 121 (rhVEGF) has been successfully expressed and efficiently secreted into the culture medium by transiently transformed moss protoplasts. In order to obtain secretion efficiency data, different expressed signal peptides were analysed and time course studies were performed with expression constructs containing different promoters. The transformation procedure was optimised for high level expression (up to 10 microg/ml) and successfully performed even with a transgenic glyco-engineered strain lacking plant-specific immunogenic sugar residues in N-glycans. The amount of rhVEGF was produced in such quantity that it allowed for the analysis of biological activity, silver-staining and Western blotting, revealing the correct formation and processing of the homodimer. This fast and flexible transient expression system enables feasibility studies and construct optimisation to be concluded within a few days, thus avoiding the time consuming step of having to generate stably transformed lines.

Cilomilast, an orally active phosphodiesterase 4 inhibitor for the treatment of COPD.

Cilomilast is a highly selective, orally active phosphodiesterase (PDE)4 inhibitor currently under evaluation for the treatment of chronic obstructive pulmonary disease (COPD). PDE4 is the predominant cyclic AMP-degrading enzyme in various inflammatory cells such as eosinophils, neutrophils, macrophages, T-cells and monocytes. As a second-generation PDE4 inhibitor, cilomilast demonstrates a markedly improved side-effect profile over the prototype rolipram. In humans, cilomilast is rapidly absorbed after oral administration and is almost completely bioavailable with nearly no first-pass hepatic metabolism. Cilomilast has been shown to be well tolerated in both short- and long-term studies in doses of up to 15 mg twice daily. Phase II and III studies demonstrated improvements in lung function and quality of life in patients with COPD. Significant reduction was observed in subepithelial neutrophil, CD68(+) monocyte and CD8(+) lymphocyte densities in bronchial biopsies of COPD patients following administration of cilomilast for 12 weeks. As there are no pharmacokinetic interactions between cilomilast and commonly prescribed drugs such as theophylline, salbutamol, erythromycin and corticosteroids, or with smoking, it can be assumed that no dose adjustments will be required in patients with COPD. Cilomilast is thus a promising substance for use in the anti-inflammatory treatment of COPD.