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EFFECT OF REPEATED EXPOSURE TO SLEEP RESTRICTION ON INTERLEUKIN 6 LEVELS IN HUMANS
Vrushank Dharmesh Bhatt, Moussa Diolombi, Monika Haack, Janet Mullington
Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215
INTRODUCTION
Program #
615.7
STUDY DESIGN
 Interleukin-6 (IL-6) is a pleiotropic cytokine produced by numerous types of
immune and nonimmune cells and is involved in many pathophysiologic
mechanisms in humans.
Sleep Period
Sleep period with intensive
physiological monitoring
Blood Draw
Urine collection (morning)
Urine collection (night)
24 hr periods with PSG
 Previous studies have suggested that IL-6 is a putative ‘sleep factor’ and its
circadian secretion correlates with sleep/sleepiness.
 Short periods of experimental sleep restriction have been shown to elevate
IL-6, which has been suggested to increase the risk for cardiometabolic
diseases.
 However, the effect of repeated exposure to sleep restriction on IL-6 is
unknown.
METHODS
RESULTS
Study Design: Participants were randomized to a 22-day study of repeated
cycles of sleep restriction (4hr sleep/night for 3 nights followed by one
recovery sleep, 4 cycles) or routine sleep (8hr sleep/night), following two
nights of baseline sleep.
DISCUSSION
Night-time Blood Draw at 2245
 The sleep restriction group showed a significant increase in IL-6 levels in
the morning during the first sleep restriction cycle, exceeding control
levels by 20% (p<0.05). These levels did not return to baseline in the
remaining sleep restriction cycles when compared with the control group.
1.8
SR1
SR2
SR4
SR3
1.6
IL-6 Measurement: Plasma concentrations of IL-6 were measured using high
sensitivity immunosorbent assay (R&D Systems ELISA), CV<15%.
1.4
IL-6 (pg/ml)
Blood Sampling: Blood was sampled from fasting recumbent participants in the
morning after awakening, during baseline, third day of each sleep restriction or
control cycle, and following recovery. Total- 13 blood draws
Condition 4
Condition 8
1.2
1
 These data suggest that a good night's sleep is associated with decreased
daytime secretion of IL-6 and a decreased exposure of tissues to this proinflammatory cytokine and potentially detrimental actions of IL-6.
0.8
Study Environment: Participants remained in the Clinical Research Center for
the duration of study, with controlled fluid and calorie intake, with normal
interaction and physical activity.
Variable
Control
Sleep Restriction
Women/Men
11/11
11/10
Age, years
31+2
0.6
3
6
24+1
10
14
18
20
Day
 IL-6 levels return to baseline levels after recovery sleep.
Figure 1: IL-6 levels
Morning-time Blood Draw at 0715
1.6
31+2
SR1
SR3
SR2
24+1
FUTURE DIRECTIONS
SR4
*
*
1.5
BMI, kg/m2
 According to recent findings, IL-6 levels are associated with increased
mortality in elderly. So the possibility that anti-inflammatory therapies
might provide a new approach to cardiovascular disease treatment and
prevention.
1.4
Habitual Sleep, h
7.8+0.1
7.8+0.1
1.3
• 1
IL-6 (pg/ml)
1.2
REFERENCES
 Though there was a slight increase in the IL-6 levels in the sleep
restriction group in the night after the first sleep restriction cycle, this
increase was not significant as compared to the baseline levels.
Condition 4
Condition 8
1.1
1
0.9
• 2
0.8
• 3
 Other inflammation markers will be analyzed to elucidate the exact
mechanism for understanding the potential association of these cytokines
with sleep, health and well-being.
0.7
• 4
ACKNOWLEDGEMENT
0.6
4
• 5
7
11
15
Day
Figure 2:
19
22
This work was supported by science research funds from National Institute of
Health (HL-106782) and Harvard Catalyst CTSC NIH UL1 TR001102.