Anti-inflammatory Effects of GTS-21 After LPS
Condition: Endotoxemia; Sepsis; Vagal Activity
MeSH terms: Endotoxemia
Study type: Interventional

Summary: 
      Rationale: The vagus nerve exerts an anti-inflammatory effect in in vitro and animal
      experiments. This 'vagal anti-inflammatory pathway' is mediated by the nicotinergic α7nACh
      receptor that can be selectively stimulated by GTS-21. Activation of the cholinergic
      anti-inflammatory pathway via vagus nerve stimulation or α7nAChR agonists improves outcome in
      animal models of endotoxemia, sepsis and experimental arthritis. Up to now, the
      anti-inflammatory effects of oral administration of GTS-21 in humans in vivo has not been
      investigated.

      Objective: Primary aim: to investigate the anti-inflammatory effects of oral administration
      of GTS-21 on the inflammatory response in the human endotoxemia model and the subsequent
      inflammation-induced subclinical organ dysfunction. Secondary aim: to measure the effect of
      LPS administration in the absence or presence of GTS-21 in human volunteers on vagal nerve
      activity measured by heart rate variability analysis.

      Study design: Double-blind placebo-controlled randomized cross-over intervention study in
      healthy human volunteers during experimental endotoxemia.

      Study population: Non-smoking healthy male volunteers, age 18-35 yrs Intervention: Subjects
      will be tested in a cross-over design in 2 separate sequential sessions, 2-4 weeks apart. A
      total of 12 subjects will be randomly assigned to one of two dosing groups in a 1:1 ratio:
      GTS-21 followed by Placebo n=6, Placebo followed by GTS-21 n=6. Subjects will receive 150mg
      GTS-21 or placebo orally tid 3 days before LPS injection and an oral dose of 150 mg GTS-21 or
      placebo the morning of the day of LPS administration (07:00 AM). Subjects will then receive
      an oral dose of 150 mg GTS-21 or placebo at 08:00 AM and another oral dose of 150 mg GTS-21
      or placebo at 1 hour before LPS administration (t=0). Before LPS injection, prehydration will
      be performed by infusion of 1.5 L 2.5% glucose/0.45% saline solution in 1 hour. One hour
      after the last dose of GTS-21 or placebo, LPS derived from E coli O:113 will be injected (2
      ng/kg iv in 1 minute). There will be a 14 day washout period for patients in all groups. The
      last group of subjects will be subjected to an identical dose of LPS and placebo at two
      different moments 2-4 weeks apart to obtain time controls.

      Main study parameters/endpoints: Main study endpoint is the concentration of circulating
      cytokines after LPS in the absence and presence of GTS-21.

      Nature and extent of the burden and risks associated with participation, benefit and group
      relatedness: A medical interview and physical examination is part of this study.
      Approximately 350 ml blood will be withdrawn and urine will be collected. There will be mild
      discomfort associated with participation in this study, as LPS induces flu-like symptoms for
      approximately 4 hrs. GTS-21 was found to be well tolerated at a dose of 150 mg three times
      daily (450 mg/day).
    

Detailed description: 
      INTRODUCTION AND RATIONALE: The innate immune response is the first line of defense against
      invading pathogens(1). This tightly regulated system consists of a wide variety of
      chemokines, cytokines, cell associated receptors and other mediators orchestrating the
      initial response to infection. Experimental evidence in the past several years has
      demonstrated that activation of the efferent vagus nerve has an inhibitory effect on the
      innate immune response (the cholinergic anti-inflammatory pathway, reviewed in (2,3,4)). The
      anti-inflammatory effect of the vagal nerve is mediated by the α7 nicotinic acetylcholine
      receptor (α7nAChR) expressed on macrophages and other cytokine-producing cells (9).
      Activation of the cholinergic anti-inflammatory pathway with vagus nerve stimulation or
      α7nAChR agonists improves outcome in animal models of endotoxemia, sepsis and experimental
      arthritis. This cholinergic anti-inflammatory pathway is the efferent arm of a reflex
      mechanism that is activated by inflammatory mediators in peripheral tissues signaling through
      the afferent vagus nerve. Thus, the vagus nerve can relay inflammation signals to the central
      nervous system and activate an opposing efferent response to inhibit excessive inflammation.

      GTS-21 (E-3-(2,4)-dimethoxybenzylidene anabaseine) is a highly specific α7nAchR agonist, that
      has been developed for the treatment of Alzheimer's disease that has been studied in a few
      inflammation-related models. In a murine pancreatitis model pre-treatment of the animals with
      GTS-21 decreased pancreatitis severity and was associated with reduced IL-6 levels and
      decreased pancreatic neutrophil accumulation (11). Pre-treatment of mice with GTS-21
      attenuated systemic TNF concentrations after injection with LPS and increases survival
      (12,13). Similarly, GTS-21 inhibited blood levels of the inflammatory mediator High Mobility
      Group Box 1 (HMGB1) and improved survival of mice after cecal ligation and puncture.(13).
      Recently, we have shown that stimulation of the α7nAChR by the highly selective agonist
      GTS-21 leads to a dramatic dose-dependent inhibition of pro-inflammatory cytokine release
      induced by stimulation of various Toll-like receptors (TLR) in human whole blood (Kox et al,
      submitted). This inhibitory effect of GTS-21 was not specific for the TLR-agonist used and
      GTS-21 inhibited pro-inflammatory cytokine production stronger than nicotine at equimolar
      concentrations. Moreover, the production of the anti-inflammatory cytokine IL-10 was not
      inhibited, but even significantly stimulated. Therefore, stimulation of the α7nAChR by GTS-21
      results in a profound anti-inflammatory shift of the pro-/anti-inflammatory balance. So far,
      no data are available on the anti-inflammatory effects of GTS-21 in humans in vivo.

      The human endotoxemia model is widely used to study inflammation in humans in vivo. Systemic
      inflammation is induced by low-dose infusion of Escherichia coli lipopolysaccharide (LPS) in
      healthy volunteers, resulting in flu-like symptoms, increased production of C-reactive
      protein and increased concentrations of pro- and anti-inflammatory cytokines. The "human
      endotoxemia model" permits elucidation of key players in this proinflammatory response in
      humans in vivo and it serves as a useful tool to investigate potential novel therapeutic
      strategies in a standardized setting.

      GTS-21 was developed as a novel agent in the treatment of Alzheimer's disease. Until date, 87
      healthy male volunteers were enrolled in four Phase I studies that assessed the safety,
      tolerability, pharmacokinetics, and effects on cognitive function of oral administration of
      GTS-21 of which 77 subjects received GTS-21 and 10 subjects received placebo. GTS-21 was
      found to be well tolerated up to a dose of 150 mg three times daily (450 mg/day) in healthy
      male subjects. The most common adverse event was headache, which occurred in 27% of subjects
      in the GTS-21 group compared to 21% of subjects in the placebo group. There were no serious
      adverse events, or severe adverse events reported during these studies. In one patient in the
      GTS-21 group transient mild elevation of liver enzymes was detected, without signs of hepatic
      dysfunction.

      PRIMARY AIM: Primary aim of the present study is to investigate the putative
      anti-inflammatory effects of oral administration of GTS-21 on the inflammatory response and
      subsequent subclinical organ dysfunction in the human endotoxemia model. Secondary aim is to
      measure the effect of LPS administration in the absence and presence of GTS-21 in human
      volunteers on vagal nerve activity.
    

Intervention name(s): GTS-21, [3-(2,4-dimethoxybenzylidene)-anabaseine dihydrochloride]; Placebo; Lipopolysaccharide E. Coli 113:H 10:K negative
Intervention type(s): Drug; Drug; Drug
Intervention description(s): Subjects will receive GTS-21 or placebo 3 day before injection of LPS (150 mg tid) and a single oral dose of 150 mg of GTS-21 or placebo the morning of LPS injection (07:00 AM). Subjects will then receive an oral dose of 150 mg GTS-21 or placebo at 08:00 AM and another oral dose of 150 mg GTS-21 or placebo at 1 hour before LPS administration (t=0); Subjects will receive placebo 3 day before injection of LPS (150 mg tid) and a single oral dose of 150 mg of placebo the morning of LPS injection (07:00 AM). Subjects will then receive an oral dose of 150 mg placebo at 08:00 AM and another oral dose of 150 mg placebo at 1 hour before LPS administration (t=0).; Subjects will be randomized to oral pre-treatment with GTS-21 (150 mg tid 3 days before LPS injection and an oral dose of 150 mg GTS-21 on the morning of the day of the experiment (07:00 AM). Subjects will then receive an oral dose of 150 mg GTS-21 or placebo at 08:00 AM and another oral dose of 150 mg GTS-21 or placebo at 1 hour before LPS administration (t=0). One hour after ingestion of the last dosage of the study drug, purified LPS prepared from E coli O:113 (2 ng/kg iv) will be injected intravenously.
Other intervention name(s): GTS-21; Test; Endotoxin
Intervention MeSH terms: 3-(2,4-dimethoxybenzylidene)anabaseine
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Treatment
Keywords: Endotoxin; GTS-21; Vagal activity; Autonomic balance