title: Characterization of a model of systemic inflammation in humans in vivo elicited by continuous infusion of endotoxin.
abstract: Investigating the systemic inflammatory response in patients with critical illness such as sepsis, trauma and burns is complicated due to uncertainties about the onset, duration and severity of the insult. Therefore, in vivo models of inflammation are essential to study the pathophysiology and to evaluate immunomodulatory therapies. Intravenous bolus administration of endotoxin to healthy volunteers is a well-established model of a short-lived systemic inflammatory response, characterized by increased plasma cytokine levels, flu-like symptoms and fever. In contrast, patients suffering from systemic inflammation are often exposed to inflammatory stimuli for an extended period of time. Therefore, continuous infusion of endotoxin may better reflect the kinetics of the inflammatory response encountered in these patients. Herein, we characterize a novel model of systemic inflammation elicited by a bolus infusion of 1 ng/kg, followed by a 3hr continuous infusion of 1 ng/kg/h of endotoxin in healthy volunteers, and compared it with models of bolus administrations of 1 and 2 ng/kg of endotoxin. The novel model was well-tolerated and resulted in a more pronounced increase in plasma cytokine levels with different kinetics and more prolonged symptoms and fever compared with the bolus-only models. Therefore, the continuous endotoxin infusion model provides novel insights into kinetics of the inflammatory response during continuous inflammatory stimuli and accommodates a larger time window to evaluate immunomodulating therapies.
authors.affiliation: Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Intensive Care Medicine, 6500 HB, Nijmegen, The Netherlands.|Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Pediatrics, 6500 HB, Nijmegen, The Netherlands.
authors.forename: D
authors.initials: D
authors.lastname: Kiers
authors.affiliation: Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Intensive Care Medicine, 6500 HB, Nijmegen, The Netherlands.|Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Pediatrics, 6500 HB, Nijmegen, The Netherlands.
authors.forename: R M
authors.initials: RM
authors.lastname: Koch
authors.affiliation: Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Intensive Care Medicine, 6500 HB, Nijmegen, The Netherlands.|Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Pediatrics, 6500 HB, Nijmegen, The Netherlands.
authors.forename: L
authors.initials: L
authors.lastname: Hamers
authors.affiliation: Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Intensive Care Medicine, 6500 HB, Nijmegen, The Netherlands.|Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Pediatrics, 6500 HB, Nijmegen, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Gerretsen
authors.affiliation: Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Intensive Care Medicine, 6500 HB, Nijmegen, The Netherlands.
authors.forename: E J M
authors.initials: EJ
authors.lastname: Thijs
authors.affiliation: Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Intensive Care Medicine, 6500 HB, Nijmegen, The Netherlands.
authors.forename: L
authors.initials: L
authors.lastname: van Ede
authors.affiliation: Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Internal Medicine, 6500 HB, Nijmegen, The Netherlands.
authors.forename: N P
authors.initials: NP
authors.lastname: Riksen
authors.affiliation: Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Intensive Care Medicine, 6500 HB, Nijmegen, The Netherlands.|Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Pediatrics, 6500 HB, Nijmegen, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Kox
authors.affiliation: Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Intensive Care Medicine, 6500 HB, Nijmegen, The Netherlands.|Radboud university medical center, 6500 HB, Radboud Institute for Molecular Life Sciences, Department of Pediatrics, 6500 HB, Nijmegen, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: Pickkers
mesh_terms: D016207:Cytokines / Q000097:blood; D004731:Endotoxins / Q000008:administration & dosage* / Q000633:toxicity*; D005334:Fever / Q000139:chemically induced; D064368:Healthy Volunteers; D006801:Humans; D007262:Infusions, Intravenous; D010949:Plasma / Q000737:chemistry; D018746:Systemic Inflammatory Response Syndrome / Q000139:chemically induced* / Q000473:pathology*
chemical_list: D016207:Cytokines; D004731:Endotoxins