Clinical trial NCT00513110: A Possible Therapeutic Role for Adenosine During Inflammation
Official title: A Possible Therapeutic Role for Adenosine During Inflammation
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE1
Conditions: Endotoxemia
Keywords: Endotoxin
Adenosine
Caffeine
AMPD1 polymorphism
Lead sponsor: Radboud University Medical Center
Sponsor class: OTHER
First posted: 2007-08-08
Enrollment: 33
Sex: MALE
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: The adenosine receptor is known for its anti-inflammatory actions and could therefore be a potential target in the treatment of sepsis and septic shock. Stimulation of the adenosine receptor could potentially lead to a decrease in inflammation and tissue damage.

Under normal conditions adenosine is formed either by an intracellular 5'nucleotidase, which dephosphorylates AMP, or by the hydrolysis of S-adenosylhomcysteine by hydrolase. An alternative pathway of AMP degradations is provided by the cytosolic enzyme AMP deaminase (AMPD), which catalyses the irreversible deamination of AMP to inosine monophosphate and ammonia.

In humans four AMPD isoforms have been described, named after the source from which they were initially purified; M (muscle), L (liver), E1 and E2 (erythrocyte), encoded by AMPD1, AMPD2 and AMPD3. Approximately 15-20% of Caucasian and African American individuals are heterozygous or homozygous for the 34C\>T variant of AMPD1.

We hypothesize that healthy volunteers who have the polymorphism for AMPD1 have a less severe inflammatory response to LPS and show less (severe) organ failure. This hypothesis is based on the expected higher levels of adenosine in patients with the AMPD1 polymorphism. This hypothesis is strengthened by the fact that patients with coronary artery disease and the AMPD1 polymorphism show improved cardiovascular survival (Anderson JL et al. J Am Coll Cardiol 2000; 36: 1248-52) possibly based on higher adenosine levels by reduced AMPD activity. Furthermore the polymorphism predicts improved clinical outcome in patients with heart failure (Loh E et al. Circulation 1999) also based on a hypothetical elevation of adenosine.

We hypothesize that:

The C34T-polymorphism of the enzyme AMP-deaminase leads to a decreased inflammatory respons and thereby a decrease of LPS-induced tissue damage.

A second hypothesis is based on the antagonism of the adenosine receptor, by caffeine;

Antagonism of the adenosine receptor by caffeine leads to an increased LPS-induced inflammatory reaction and an increase in (subclinical) tissue damage?


Eligibility criteria: Inclusion Criteria:

* Healthy male volunteers

Exclusion Criteria:

* Drug-, nicotine-, alcohol abuses
* Tendency towards fainting
* Relevant medical history

Primary outcomes:
measure: Hemodynamics; heart rate variability
timeFrame: 24 hrs after LPS administration
measure: Markers of Inflammation
timeFrame: 24 hrs after LPS administration
measure: Cytokines
timeFrame: 24 hrs after LPS administration
measure: Sensitivity to norepinephrine
timeFrame: 24 hrs after LPS administration
measure: Endothelial-dependent and independent vasorelaxation
timeFrame: 24 hrs after LPS administration
measure: Mediators of Vascular reactivity
timeFrame: 24 hrs after LPS administration
measure: Markers of endothelial damage and circulating endothelial cells
timeFrame: 24 hrs after LPS administration
measure: Urinary excretion of markers of renal injury
timeFrame: 24 hrs after LPS administration
measure: Neurologic testing
timeFrame: 24 hrs after LPS administration
measure: Adenosine and related nucleotide concentrations.
timeFrame: 24 hrs after LPS administration
measure: Additional blood samples will be drawn for measurement of: TLR-expression, Genetics; micro array analyses and determination of intercellular signalling pathways.
timeFrame: 24 hrs after LPS administration
Secondary outcomes:
Other outcomes:
Locations:
city: Nijmegen
country: Netherlands
facility: Radboud University Nijmegen Medical Centre
state: Gelderland
Study officials:
affiliation: Radboud University Medical Center
name: Peter Pickkers, MD,PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Ramakers BP, Riksen NP, van den Broek P, Franke B, Peters WH, van der Hoeven JG, Smits P, Pickkers P. Circulating adenosine increases during human experimental endotoxemia but blockade of its receptor does not influence the immune response and subsequent organ injury. Crit Care. 2011;15(1):R3. doi: 10.1186/cc9400. Epub 2011 Jan 6.
citation: van den Boogaard M, Ramakers BP, van Alfen N, van der Werf SP, Fick WF, Hoedemaekers CW, Verbeek MM, Schoonhoven L, van der Hoeven JG, Pickkers P. Endotoxemia-induced inflammation and the effect on the human brain. Crit Care. 2010;14(3):R81. doi: 10.1186/cc9001. Epub 2010 May 5.