Chronodisruption, Metabolic Homeostasis, and the Regulation of Inflammation in Adipose Tissues

Abstract

Molecular circadian clocks align daily behavioral and metabolic rhythms with the external day-night cycle. Priming energy metabolism for recurring changes on a 24-hour basis, these clocks are deeply interlinked with metabolic homeostasis and health. Circadian rhythm disruptions, as occurring in shift work or sleep disorders, are often accompanied by metabolic disturbances - from the promotion of overweight and type-2 diabetes to the development of the metabolic syndrome. An important indicator of the adverse outcomes of overweight seems to be a systemic low-grade inflammation which is initially observed in adipose tissues and is promoted by circadian misalignment. Interestingly, the genetic disruption of circadian clocks in rodents leads to metabolic dysregulations very comparable to what is observed in shift workers and with the development of tissue specific clock gene knockout mice, the importance of single-tissue clocks for the metabolic regulation was further deciphered. In this review, we summarize the current knowledge on the role of mistimed behavior in metabolic health and outline behavioral interventions aiming at reducing the metabolic ramifications of chronodisruption.

Keywords: adipose tissue; chronodisruption; circadian clocks; inflammation; metabolism.

Figure 1

Diurnal adipose tissue homeostasis. During active/ daytime hours food is consumed and white adipose tissue stores Glucose and lipids. During the dark and fasting night fatty acids are released, supported by melatonin. Undisturbed cycles stabilize the metabolic homeostasis (green). Mistimed eating, nocturnal light and sleep disruption inhibit this timed processes (red).