Effect of Fasting and Refeeding on T-cell Fate

Intermittent caloric restricted or fasting has numerous health effects including the
reduction in numerous cardiovascular and pulmonary disease risk factors. The cellular
programs activated by caloric restriction are similarly regulated in preclinical and clinical
studies in response to a 24-hour fast. We have found that a beneficial effect of a 24-hour
fasting blunts the activation of a component of the innate immune system, termed the NLRP3
inflammasome. This inflammasome, as a mediator of sterile inflammation, is associated with
the development of diabetes, asthma and atherosclerosis. At the same time, we found that
refeeding after the 24-hour fast significantly increased NLRP3 protein levels. As NLRP3 is
increased in obesity, the nutrient intervention (24 hour fast and then refeeding) we studied
may be useful to evaluate nutrient-overload effects on the immune system. Pertaining to this
it has recently been found in a preclinical study that NLRP3 can also orchestrate
differentiation of na(SqrRoot) ve T cells into T(H)2 cells. Interestingly both the NLRP3
inflammasome and T(H)2 cell activation contribute to asthma. In this context we hypothesize
that the assessment of the effect on refeeding on T(H)2 cell differentiation (polarity) may
allow us to dissect out the mechanisms underpinning nutrient overload induced T(H)2 cell
activation. To evaluate this blood samples to test T-cell biology will be collected in
subjects, at baseline, after a fixed caloric meal and in response to a 24-hour fast (water
intake will not be restricted). The objective of this pilot study is to identify if
nutrient-load regulates T-Cell differentiation capacity and to test whether this pathway
could be investigated as a therapeutic target to blunt/negate the inflammation associated
with nutrient-excess associated diseases including asthma.

- INCLUSION CRITERIA:

As this is a pilot study, the age-range and BMI range of subjects will be restricted to
potentially reduce metabolic variables associated with a wide age- and BMI-range.

- Males and females between the ages of 21 and 37

- BMI greater than or equal to 22 and less than 30

EXCLUSION CRITERIA:

- Subjects with an acute or chronic illness as per history, on laboratory analysis or
due to use of medications

- Subjects taking vitamins or supplements or any medications, except oral
contraceptives, within 4 weeks of participation into this study

- BMI less than 22 or greater than or equal to 30

- Female subjects who are pregnant or lactating

- Subjects who have donated blood or participated in another clinical trial involving
blood draws in the last 8 weeks

- Subjects who use nicotine products