Week 7 - ANHB3316 - Circadian Rhythms & Chronodisruption

What proportion of protein-coding genes show circadian rhythmic transcription?

43%, largely in an organ-specific manner (especially high in liver and kidneys).

What controls the initial maternal-foetal circadian rhythm?

Maternal factors such as sleep/wake cycle, hormones, blood pressure, heart rate, and temperature.

When does foetal clock gene and SCN rhythmicity begin?

Late in gestation.

How can antenatal steroids disrupt foetal circadian rhythms?

Night-time dosing elevates cortisol levels at an inappropriate time, opposing maternal rhythms and increasing thymic apoptosis.

What is the effect of morning vs night steroid administration on lung development?

Morning dosing improves lung maturity; night dosing leads to poorer outcomes.

How long after discharge do preterm infants typically develop circadian rhythms?

6–12 weeks.

What environmental factor in NICU affects preterm infants’ CR development?

Constant light or darkness delays rhythm establishment; light–dark cycles promote earlier CR development.

List 3 long-term consequences of early chronodisruption.

Poor weight gain, impaired neurodevelopment, chronic airway disease.

Why do wounds heal faster during the active circadian phase?

Cells migrate and repair more rapidly during active/awake phase.

What does the CIRCA DIEM study aim to evaluate?

The effect of cycled light and noise exposure on preterm infant outcomes.