Showing papers by "Frank Hanses published in 2012"

Leishmania major infection in humanized mice induces systemic infection and provokes a nonprotective human immune response.

Abstract: Background Leishmania (L.) species are the causative agent of leishmaniasis. Due to the lack of efficient vaccine candidates, drug therapies are the only option to deal with cutaneous leishmaniasis. Unfortunately, chemotherapeutic interventions show high toxicity in addition to an increased risk of dissemination of drug-resistant parasites. An appropriate laboratory animal based model is still missing which allows testing of new drug strategies in the context of human immune cells in vivo. Methodology/Principal Findings Humanized mice were infected subcutaneously with stationary phase promastigote L. major into the footpad. The human immune response against the pathogen and the parasite host interactions were analyzed. In addition we proved the versatility of this new model to conduct drug research studies by the inclusion of orally given Miltefosine. We show that inflammatory human macrophages get infected with Leishmania parasites at the site of infection. Furthermore, a Leishmania-specific human-derived T cell response is initiated. However, the human immune system is not able to prevent systemic infection. Thus, we treated the mice with Miltefosine to reduce the parasitic load. Notably, this chemotherapy resulted in a reduction of the parasite load in distinct organs. Comparable to some Miltefosine treated patients, humanized mice developed severe side effects, which are not detectable in the classical murine model of experimental leishmaniasis. Conclusions/Significance This study describes for the first time L. major infection in humanized mice, characterizes the disease development, the induction of human adaptive and innate immune response including cytokine production and the efficiency of Miltefosine treatment in these animals. In summary, humanized mice might be beneficial for future preclinical chemotherapeutic studies in systemic (visceral) leishmaniasis allowing the investigation of human immune response, side effects of the drug due to cytokine production of activated humane immune cells and the efficiency of the treatment to eliminate also not replicating (“hiding”) parasites.

The novel adipokine C1q/TNF-related protein-3 is expressed in human adipocytes and regulated by metabolic and infection-related parameters.

Abstract: BACKGROUND The growing family of C1Q/TNF-related proteins is characterized by structural homologies to the anti-inflammatory adipokine adiponectin. CTRP-3 was recently reported to function as an anti-inflammatory LPS-antagonist in vitro. MATERIAL AND METHODS Human subcutaneous and visceral adipocytes and murine 3T3-L1 adipocytes were used for analysis of CTRP-3 expression and function. Western blot analysis of CTRP-3, siRNA mediated knockdown of CTRP-3, Oil red O staining, assessment of basal and epinephrine-induced lipolysis, ELISA-based measurements of supernatant chemokines, recombinant CTRP-3 protein expression, and Staphylococcus aureus (S. aureus) infection assays were used. RESULTS CTRP-3 is expressed in subcutaneous and visceral adipocytes. CTRP-3 is positively regulated by insulin, whereas chronic LPS-exposure inhibits terminal adipocyte differentiation and CTRP-3 expression. Intracellular infection of adipocytes by S. aureus also decreases CTRP-3 expression. As demonstrated by siRNA-mediated cellular knockdown of CTRP-3 in adipocytes, CTRP-3 regulates resistin secretion and lipolysis. CONCLUSION CTRP-3 is expressed in human adipocytes and plays an important role in adipocyte physiology such as lipolysis and adipokine secretion. Both, metabolic factors and infection/inflammation-related factors regulate CTRP-3 expression.

Fieber ungeklärter Genese

Abstract: Infektionen sind mit einem Anteil von etwa 30% eine der haufigsten Ursachen eines ungeklarten Fiebers Das Spektrum der Infektionen hangt von der klinischen Situation bzw vom Risikoprofil des Patienten ab und variiert hinsichtlich der Kategorien des „klassischen“ Fiebers ungeklarter Genese und des ungeklarten Fiebers bei HIV-Infektion, bei immunsupprimierten Patienten und bei nosokomialem Fieber Die wichtigste Frage ist, welche Eigenschaften von Erreger und Wirt eine spezifische Infektion zur Ursache eines ungeklarten Fiebers machen konnen