LPS-Induced Lung Inflammation in Marmoset Monkeys – An Acute Model for Anti-Inflammatory Drug Testing

et al. (2012) LPS-Induced Lung Inflammation in Marmoset Monkeys - An Acute Model for Anti-Inflammatory Drug Testing. PLoS ONE 7(8): e43709. doi:10.1371/journal.pone.0043709 LPS-Induced Lung Inflammation in Marmoset Monkeys - An Acute Model for Anti-Inflammatory Drug Testing Sophie Seehase 0 Hans-Dieter Lauenstein 0 Christina Schlumbohm 0 Simone Switalla 0 Vanessa Neuhaus 0 Christine Fo rster 0 Hans-Gerd Fieguth 0 Olaf Pfennig 0 Eberhard Fuchs 0 Franz- Josef Kaup 0 Martina Bleyer 0 Jens M. Hohlfeld 0 Armin Braun 0 Katherina Sewald 0 Sascha Knauf 0 Marco Idzko, University Hospital Freiburg, Germany 0 1 Airway Research, Fraunhofer Institute for Toxicology and Experimental Medicine , Hannover, Germany , 2 Pathology Unit, German Primate Center, Leibniz-Institute for Primate Research , Go ttingen, Germany, 3 Encepharm GmbH, Go ttingen, Germany , 4 Institute of Pathology, Klinikum Region Hannover Klinikum Nordstadt, Hannover, Germany, 5 Division of Thoracic Surgery, Klinikum Region Hannover Klinikum Oststadt-Heidehaus , Hannover , Germany Increasing incidence and substantial morbidity and mortality of respiratory diseases requires the development of new human-specific anti-inflammatory and disease-modifying therapeutics. Therefore, new predictive animal models that closely reflect human lung pathology are needed. In the current study, a tiered acute lipopolysaccharide (LPS)-induced inflammation model was established in marmoset monkeys (Callithrix jacchus) to reflect crucial features of inflammatory lung diseases. Firstly, in an ex vivo approach marmoset and, for the purposes of comparison, human precision-cut lung slices (PCLS) were stimulated with LPS in the presence or absence of the phosphodiesterase-4 (PDE4) inhibitor roflumilast. Proinflammatory cytokines including tumor necrosis factor-alpha (TNF-a) and macrophage inflammatory protein-1 beta (MIP1b) were measured. The corticosteroid dexamethasone was used as treatment control. Secondly, in an in vivo approach marmosets were pre-treated with roflumilast or dexamethasone and unilaterally challenged with LPS. Ipsilateral bronchoalveolar lavage (BAL) was conducted 18 hours after LPS challenge. BAL fluid was processed and analyzed for neutrophils, TNF-a, and MIP-1b. TNF-a release in marmoset PCLS correlated significantly with human PCLS. Roflumilast treatment significantly reduced TNF-a secretion ex vivo in both species, with comparable half maximal inhibitory concentration (IC50). LPS instillation into marmoset lungs caused a profound inflammation as shown by neutrophilic influx and increased TNF-a and MIP-1b levels in BAL fluid. This inflammatory response was significantly suppressed by roflumilast and dexamethasone. The close similarity of marmoset and human lungs regarding LPS-induced inflammation and the significant anti-inflammatory effect of approved pharmaceuticals assess the suitability of marmoset monkeys to serve as a promising model for studying anti-inflammatory drugs. - Competing Interests: Fraunhofer ITEM is a public non-profit research organisation doing contract research for e.g. pharmaceutical and biotech industry. The institution of JMH has received research grants from AstraZeneca, Novartis, Nycomed, and Pfizer to conduct clinical trials using LPS-induced inflammation. Encepharm is a research organisation doing contract research for e.g. pharmaceutical and biotech industry. The institution has received no grants to conduct preclinical trials using LPS-induced inflammation in marmoset monkeys. Encepharm confirms that this does not alter the authors adherence to all the PLoS ONE policies on sharing data and materials, as detailed online in the guide for authors. CF declares affiliation to the company Klinikum Region Hannover GmbH. This does not alter the authors adherence to all the PLoS ONE policies on sharing data and materials. . These authors contributed equally to this work. Inflammatory lung diseases including pneumonia, acute lung injury (ALI), acute respiratory distress syndrome (ARDS), and chronic obstructive pulmonary disease (COPD) cause significant morbidity and mortality worldwide and display a major public health impact [1;2]. On cellular level, these respiratory diseases are based on inflammation which can be either acute or chronic. The inflammatory process is characterized by an increased expression of multiple cytokines and chemokines. In particular, activated macrophages and epithelial cells produce inflammatory mediators such as tumor necrosis factor alpha (TNF-a) and interleukin-1 beta (IL-1b) which in turn induce the attraction of neutrophils and the release of further cytokines including IL-6 [3]. These inflammatory aspects of cytokine up-regulation can also be mimicked in in-vitro, ex vivo, as well as in vivo approaches by using infectious or environmental stimuli [48]. Especially the endotoxin lipopolysaccharide (LPS), which is part of the outer membrane of gram-negative bacteria, is one of the most potent immuneactivating stimuli known. LPS induces a profound activation of the innate immunity via CD14 and Toll-like receptor (TLR) 4 that results in a strong inflammatory response due to activation of the transcription factor NF-kB [9;10]. LPS is, therefore, widely used to model features of inflammatory diseases in vitro as well as in vivo. Acute respiratory LPS challenge models in animals as well as in humans which are characterized by bronchoalveolar neutrophil influx and cytokine up-regulation, have extensively been used for the testing of new anti-inflammatory drugs [4;8;11;12], although they do not reflect all features of human, notably chronic, respiratory diseases. So far, corticosteroids have widely been used for the anti-inflammatory treatment of inflammatory lung diseases. However, they provide only little benefit in disease progression or mortality [13;14]. Thus, development of new, effective antiinflammatory drugs is urgently needed. Particularly, antagonists or inhibitors targeting the mechanisms involved in recruitment and accumulation of inflammatory cells, including neutrophils, display promising options for therapeutic intervention in lung inflammation [15]. In fact, a first success has been achieved with the highly potent phosphodiesterase-4 (PDE4) inhibitor roflumilast [11;16], which was extensively tested on acute respiratory LPS challenge models [4;8;11]. Preclinical testing of highly specific anti-inflammatory drugs requires valid translational animal models [17]. Yet, rodent models have commonly been used, even though they are often limited in reflecting the human pathology [18;19]. Rodents in contrast to non-human primates (NHP) or humans have less extensive airway branching and normally do not have respiratory bronchioles [19]. The close phylogenetic relationship between NHP and humans, and the resulting high homology to a variety of human target structures make NHP interesting for preclinical testing of newly developed drugs [18]. The New Worl (...truncated)