Possible Links Between Inflammation and Lipid Metabolism
Condition: Sepsis; Inflammation; LPS; Lipid Metabolism Disorder
MeSH terms: Metabolic Diseases; Lipid Metabolism Disorders; Inflammation
Study type: Interventional

Summary: 
      It has been recognized lately that sepsis and inflammation has an important impact on lipid
      metabolism and that the extent of hypocholesterolemia may even be a marker of severity of
      illness. However, the interplay between inflammation and the marked changes in lipid
      metabolism remain to be sufficiently understood. Importantly, the exact kinetics of lipid
      parameters in inflammatory conditions are yet to be explored. This study aims to investigate
      the interaction between inflammation and lipid metabolism using the human endotoxin model
      (LPS infusion) in ten healthy volunteers in a single blinded randomized placebo controlled
      cross-over design.
    

Detailed description: 
      Sepsis is a severe clinical syndrome with still limited means of therapy and often poor
      prognosis. It has been recognized lately that sepsis and inflammation has an important impact
      on lipid metabolism and that the extent of hypocholesterolemia may even be a marker of
      severity of illness.

      This study aims to investigate the interaction between inflammation and lipid metabolism and
      the possible role of various markers of lipid metabolism including apolipoprotein B, apoA1
      and lipoprotein(A) using the human endotoxin model in ten healthy volunteers. In this model,
      volunteers are infused intravenously with bacterial lipopolysaccharide (LPS, 2 ng/kg over 5
      minutes) to simulate human sepsis. Immediately after the infusion of LPS, proinflammatory
      cytokines and other mediators are elevated just as they are in common sepsis. This widely
      used model thus represents a reliable method for evaluating conditions during inflammation.

      In this study, LPS will be administered to ten healthy male volunteers aged 18-40 years and
      plasma levels of lipid parameters including those described above will subsequently be
      measured repeatedly to evaluate the influence of LPS on lipid metabolism and detailed
      kinetics of lipid parameters.

      This project is planned as a prospective, single blinded randomized, placebo controlled
      cross-over study. Participants must be free of disease history and previous anaphylactic
      events, must not be on any medication and will be screened for medical disorders including
      renal, hepatic and cardiovascular conditions, thrombophilia and infections in an initial
      medical examination. Each participant will be studied on two different study days with a
      washout period of at least 14 days, on which either LPS (National Reference Bacterial
      Endotoxin, lot EC-6, prepared from Escherichia coli 0113, USPC, Inc. Rockville, MD) and
      saline or saline alone as a placebo will be administered. LPS will be infused in a dosage of
      2 ng/kg over a period of 5 minutes. Participants will be studied after an overnight fast and
      after 24 hours without smoking and without consumption of caffeine-containing beverages in
      order to ensure standard baseline conditions. During the study, subjects will rest in a
      supine position. Infusion and sampling will be done using two separate intravenous catheters.

      Blood samples will be centrifuged, transferred into chilled tubes and placed on ice. Plasma
      will be frozen at -80°C until it will be assayed. Plasma and urine sodium, potassium,
      creatinine and glucose will be measured via routine laboratory techniques.

      A case record form will be completed for each volunteer and data will subsequently be handled
      in an anonymous manner. Data will be analysed using repeated measures ANOVA.

      In summary, this study aims to evaluate the interactions between sepsis and lipid metabolism
      using the human endotoxin model. Such knowledge could improve the understanding of the
      pathophysiology in sepsis and may lead to the development of novel therapeutic strategies.
      Insights on possible interactions between inflammation and lipid metabolism could also
      enlighten pathophysiological pathways in metabolic syndrome and type 2 diabetes mellitus
      causing chronic low-grade inflammation with potential impact on various medical fields.
    

Intervention name(s): LPS infusion
Intervention type(s): Biological
Intervention description(s): infusion of LPS 2 ng/kg over 5 minutes
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Basic Science