Interleukin-6 (IL-6) response to a simulated night-shift schedule is modulated by brain-derived neurotrophic factor (BDNF) genotype

ABSTRACT

The BDNF gene contains a polymorphism (Val66Met) that influences sleep and may be associated with more flexible adaptation to circadian misalignment. Fifteen adult men (10 Val/Val homozygotes, 5 Val/Met heterozygotes) participated in a laboratory study involving two 5 d cycles of simulated night shifts. Circulating interleukin-6 (IL-6) was measured from plasma, sleep was recorded polysomnographically, and performance was measured using a psychomotor vigilance test. Compared to Val/Val homozygotes, heterozygotes exhibited a blunted IL-6 temporal (diurnal) pattern, less daytime sleep restriction, and less nighttime performance impairment after the first simulated night-shift cycle. These observations suggest that heterozygotes experienced more flexible circadian adaptation.

KEYWORDS:

• Circadian adaptation
• circadian misalignment
• IL-6 diurnal pattern
• immune response
• laboratory study
• physiological stressor response
• shift work
• single nucleotide polymorphism
• sleep loss

Acknowledgements

We thank the laboratory staff and the volunteer subjects. We also thank Thomas Balkin, Melissa Mallis, and Siobhan Banks, who served as a peer-review committee for the design and analysis of this study. The research was supported by the Federal Motor Carrier Safety Administration (FMCSA) under contract DTMC75-07-D-00006; an Elliot D. Weitzman, M.D. Research Grant from the Sleep Research Society Foundation; and U.S. Army Medical Research and Development Command award W81XWH-18-1-0100.

Disclosure statement

The authors report no conflicts of interest.

Additional information

Funding

This work was supported by the U.S. Army Medical Research and Development Command [W81XWH-18-1-0100]; Federal Motor Carrier Safety Administration [DTMC75-07-D-00006]; Sleep Research Society Foundation [Elliot D. Weitzman, M.D. Research Grant].