Abstracts: 28th International Winter-Workshop on Clinical, Chemical, and Biochemical Aspects of Pteridines

Abstract

Chlamydia pneumoniae is an obligatory intracellular bacterium causing acute respiratory infection and chronic inflammatory diseases in humans. The role of C. pneumoniae as well as the role of iron for the pathogenesis of atherosclerosis are under discussion. The influence of iron and interferon-gamma (IFN-γ) on immune effector pathways in C. pneumoniae infected endothelial cells and monocytes was investigated.Human endothelial cells (EA.hy923) and monocytic cells (THP-1) were infected with C. pneumoniae and different challenges were added: iron, deferoxamine (DFO) and 1-Methyltryptophan (1-MT), the latter inhibiting the tryptophan degrading enzyme indoleamine-2,3-dioygenase (IDO), before cells were stimulated with IFN-γ or left untreated. The numbers of infected cells as well as inclusion bodies were counted and kynurenine, tryptophan, neopterin and tumor necrosis factor-alpha (TNF-α) were determined.In EA.hy926 cells iron supplementation and DFO promoted the infection with Chlamydia, while 1-MT and IFN-γ treatment resulted in a significant decrease of infected cells with IFN-γ causing a more sustained reduction. In contrast, THP1 cells revealed a significant decrease of inclusion numbers with DFO and 1-MT and even more for iron. The activity of indoleamine-2,3-dioxygenase, the secretion of neopterin and TNF-α formation were not significantly different between iron-enriched, iron-deprived and IDOinhibited THP-1-cells upon IFN-γ-stimulation, respectively. In endothelial EA.hy923 cells IDO was inducible after sole infection with Chlamydia as well as additional stimulation with IFN-γ. Neopterin concentrations were rather low and were unaffected by the various challenges.The proliferation of C. pneumoniae is differently affected upon IDO inhibition and iron restriction between endothelial and monocytic cells. While C. pneumoniae within endohelial cells appears to be dependent on a sufficient exogenous supply of iron and tryptophan these pathways appear to be less important for Chlamydia residing within monocytes. In the last decades the preparation, the preservation and at least the offer of food have led to changes in quantity and quality of food consumption. A few of different techniques were developed to preserve aliments. One widely diffused technique is the addition of antioxidants, e.g. sodium sulfite (E221), sodium benzoate (E211) and food colorants, e.g. curcumin (E100) to food. These food additives prevent the growth of bacteria and other microorganisms. Furthermore, changes of lifestyle including overnutrition and physical inactivity have led to a rise of severe obesity. Leptin, an adipocytokine, which is secreted mainly by adipocytes, is produced in proportion to fat stores. Circulating leptin serves to communicate the state of body energy repletion to the central nervous system (CNS) in order to suppress food intake. Furthermore, it is involved in the homeostasis of energy limiting the accumulation of triglycerides in liver and skeletal muscle and modulating pancreatic β-cells function. The aim of this s...