Journal of Translational Medicine (Jun 2012)

A human model of inflammatory cardio-metabolic dysfunction; a double blind placebo-controlled crossover trial

  • Mehta Nehal N,
  • Heffron Sean P,
  • Patel Parth N,
  • Ferguson Jane,
  • Shah Rachana D,
  • Hinkle Christine C,
  • Krishnamoorthy Parasuram,
  • Shah Rhia,
  • Tabita-Martinez Jennifer,
  • Terembula Karen,
  • Master Stephen R,
  • Rickels Michael R,
  • Reilly Muredach P

DOI
https://doi.org/10.1186/1479-5876-10-124
Journal volume & issue
Vol. 10, no. 1
p. 124

Abstract

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Abstract Background Chronic inflammation may contribute to insulin resistance (IR), metabolic syndrome and atherosclerosis although evidence of causality is lacking in humans. We hypothesized that very low-dose experimental endotoxemia would induce adipose tissue inflammation and systemic IR during a low-grade but asymptomatic inflammatory response and thus provide an experimental model for future tests of pharmacologic and genomic modulation of cardio-metabolic traits in humans. Methods Ten healthy, human volunteers (50% male, 90% Caucasian, mean age 22.7 ± 3.8) were randomized in a double-masked, placebo-controlled, crossover study to separate 36-hour inpatient visits (placebo versus intravenous-LPS 0.6 ng/kg). We measured clinical symptoms via the McGill pain questionnaire and serial vital signs. Plasma and serum were collected for measurement of cytokines, C-reactive protein, insulin and glucose, serial whole blood & subcutaneous adipose tissue mRNA expression were measured by real-time PCR. HOMA-IR, a well-validated measure of IR was calculated to estimate insulin resistance, and frequently sampled intravenous glucose tolerance testing (FSIGTT) was performed to confirm an insulin resistant state. We performed ANOVA and within subject ANOVA to understand the differences in cytokines, adipose tissue inflammation and IR before and after LPS or placebo. Results There was no significant difference between placebo and LPS in clinical responses of symptom scores, body temperature or heart rate. However, low-dose endotoxemia induced a rapid and transient 25-fold induction of plasma TNF-alpha and 100-fold increase in plasma IL-6 (Figure 1B) (p p p = 0.01) increased with MCP-1 (peak 10-fold, F = 5.6, p p p p Conclusions We present a low dose human endotoxemia model of inflammation which induces adipose tissue inflammation and systemic insulin resistance in the absence of overt clinical response. Such a model has the potential for broad and safe application in the study of novel therapeutics and genomic influences in cardio-metabolic disease.

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