the influence of remote ischemic preconditioning on inflammation during human endotoxemia, a pilot proof-of-principle study

In a wide range of auto-inflammatory and infectious diseases attenuation of the
immune response could be beneficial. Remote ischemic preconditioning (RIPC) has
been identified as a means of protecting patients undergoing cardiac surgery
from perioperative myocardial ischemic damage. This protection can be divided
in a `first window of protection` directly after preconditioning and a `second
window` that protects patients 12-48 hour after preconditioning. Repeated RIPC
might have additional value, possibly by combining beneficial effects of the
first and second windows of protection. The mechanisms behind these effects are
under investigation, but attenuation of the inflammatory response is a major
candidate. However, this has not yet been demonstrated in the setting of
systemic inflammation in humans in vivo. This study aims to investigate the
effects of (repeated) ischemic preconditioning on inflammation during human
endotoxemia.

To determine the effect of RIPC of the upper limb on the inflammatory response
during human endotoxemia (infusion of LPS), as well as the additional effect of
7-day RIPC compared with single-dose RIPC.

A parallel randomized controlled pilot study in healthy male volunteers during
experimental endotoxemia. Subjects will be randomized to either:
1. The multiple-dose RIPC group (n=10): a group of 10 subjects that will
receive 4 cycles of remote ischemic preconditioning of the upper limb per day
in the 7 consecutive days before the endotoxemia experiment. The last dose will
be applied 40 minutes before LPS administration.
2. The single-dose RIPC group (n=10): a group of 10 subjects that will receive
a single RIPC dose, starting 40 minutes before LPS administration.
3. The control group (n=10): a group of 10 subjects that will be administered
LPS without RIPC.

A blood-pressure cuff with handheld rubber inflation balloon and manometer is
placed on the non-dominant arm of the subject. The cuff will be placed
proximally from the elbow with the most proximal part of the cuff placed in the
armpit. The cuff will be inflated to 250 mmHg after which a 5 minute countdown
is started. After 5 minutes the pressure is released and the 5 minute countdown
for reperfusion is started. This concludes one cycle out of a total of four.

1 *RIPC-dose* consists of 4 cycles of 5 minute ischemia followed by 5 minute
reperfusion as described above.

The burden of the study procedures consists of two visits to the hospital for
the single-dose RIPC and placebo groups:
* A screening visit of approximately 1 hour in which a medical interview,
physical examination and a blood withdrawal by vena puncture will be carried
out.
* The endotoxemia experiment day, on which the subjects will be hospitalized
for approximately 10 hours. An arterial line for hemodynamic monitoring and
blood sampling will be placed under local anesthesia using 2% lidocaine. A
venous cannula will be placed for intravenous fluid infusion.

Subjects in the multiple-dose RIPC group will visit the hospital 8 times. The
screening visit (1 hour) and endotoxemia experiment day (10 hours) are the same
as for the single-dose RIPC and placebo group. On the 6 days preceding the
experiment day the subjects in the multiple-dose RIPC group will visit the
hospital 6 times for 35 minutes. Subjects will receive a blood pressure cuff
that is inflated to 250 mmHg of pressure for 5 minutes and is deflated for 5
minutes before being inflated again (see for detailed description section 5.1)

The subjects will not benefit directly from participation to the study. A
subject fee is provided which is slightly higher for subjects in the
multiple-dose RIPC group. A structured risk assessment is provided in section
13. We feel that the risk to, and burden for the subjects are in proportion to
the potential value of the research.