The lifespan of human neutrophils, eosinophils, basophils and monocytes under homeostatic conditions

Remarkably little is known about the lifecycle of the cells of the innate
immune system: monocytes, neutrophils, eosinophils and basophils. Knowledge
about this lifecycle is important for fundamental insights in the immune system
and also for the understanding of pathologies of inflammatory diseases. An
important difficulty is the development of new medications is is the lack of
knowledge on the basal characteristics of the cells that cause chronic
inflammation: how fast they are produced, how long they remain in the blood and
tissues and where they are cleared. Little is described in literature regarding
these topics. In the 60's and 70's studies were performed on the lifespans of
innate immune cells, but with inadequate techniques. These data probably
underestimate the lifespans of these cells, but they are still mentioned in
modern tekst books.

The results of this study will lead to an improved insight in the lifecycle of
these cells and our results will be of importance for more insight in chronic
inflammatory diseases. For example, it will improve our ability to interpret
the results from previous and future intervention studies that block survival
and production of leukocytes.

On day one the volunteers will go to the clinic on an empty stomach.
First we will withdraw 20ml of blood for baseline measurements of glucose
levels and DNA deuterium enrichment.
After that, the volunteers will be orally administered 1g of deuterated glucose
per kilogram bodyweight in 12 doses over a period of 6 hours. Also, after 1, 3
and 6 hours after the first administration we will withdraw two drops of blood
by skinprick to determine the amount of deuterated glucose in the blood of the
volunteer.
During this day, the volunteer will receive low-carb breakfast and lunch.

At 5 more timepoints, the volunteer will come to the clinic to donate 20ml of
blood. The exact days after intake of glucose differ for each volunteer but
will not be in weekends or more than two days in a row. (A clear scheme of the
withdrawals can be found in the "onderzoeksprotocol", paragraph 3.2.)
From the collected blood DNA will be isolated and white blood cell populations
will be separated using high performance FACS sorting. DNA from these cells
will be isolated and analysed for deuterium enrichment using a combination of
gas chromatography and mass-spectometry.
These data will be fed to a mathematical model, which can calculate the
half-lives of the cells.

Risks:
The glucose used is considered safe, so risks are negligible

Burden:
Subject will pay five visits to the clinic for blood withdrawl. Each visit,
20ml of blood will be withdrawn, which can be easily missed by adults.
Besides, subjects will spend one day in hospital for one blood withdrawal and
the intake of 1g/kg bodyweight of glucose

Taken together, we think that the risks vor volunteers are minimal and the
burden is low.