None listed
Conditions
Brief summary
A circadian rhythm is any endogenous biological process exhibiting an entrainable daily oscillation. Circadian rhythms are essential for normal physiological and behavioural functioning and alignment with the 24 h light/dark cycle. Circadian rhythms are coordinated by a set of rhythmically expressed clock genes. A ‘master clock’ in the hypothalamic suprachiasmatic nucleus (SCN) synchronises peripheral cellular clocks and hormonal rhythmicity (e.g., plasma melatonin and cortisol concentrations). Light is the dominant environmental cue setting the rhythm of the SCN master clock. The developing fetus is not exposed to light. The development of the fetal circadian system is driven by maternal variation in circadian hormones transmitted to the fetus via the placenta. The fetus cannot synthesise its own hormones until near term. Premature delivery deprives the fetus of these materno-placental circadian cues. Hospitalisation of preterm infants in the neonatal intensive care unit (NICU) further disrupts circadian input and rhythm development due to constant lighting and noise, and invasive procedures/therapies. This prospective study is observational and investigates the circadian rhythm development across infants of different gestational ages; gestation specific patterns will be identified from physiological, hormonal and molecular outcome variables. This study will inform a second prospective study; a randomised-controlled trial of two interventions to normalise circadian rhythm development in preterm infants: modification of environmental light/dark information; and environmental modification with additional time-specific supplementation of endogenous circadian hormones (melatonin and cortisol). The clinical trial will identify if a circadian intervention improves short-term clinical outcomes.
Interventions
This study compromises the collection of salival and buccal swabs. An initial set of baseline swabs will be collected with the first 72 hours postpartum, and are taken every 4 hours for the selected 24-hour period (i.e day 2 of life at 04h00/08h00/12h00/16h00/20h00/00h00). Thereafter, buccal and saliva swabs will be taken in the same manner (i.e. every 4 hours for 24 hours) on day 14 and day 28 postnatal age. We will also take the same set of saliva and buccal swabs (every 4 hours for 24 hours)
This study compromises the collection of salival and buccal swabs. An initial set of baseline swabs will be collected with the first 72 hours postpartum, and are taken every 4 hours for the selected 24-hour period (i.e day 2 of life at 04h00/08h00/12h00/16h00/20h00/00h00). Thereafter, buccal and saliva swabs will be taken in the same manner (i.e. every 4 hours for 24 hours) on day 14 and day 28 postnatal age. We will also take the same set of saliva and buccal swabs (every 4 hours for 24 hours) at week 36 postmenstrual age, and 1, 2 and 3 months corrected postnatal age. Infant weight, length and head circumference will be measured on the above sampling days and an actimeter will be fitted to the infant to measure physical activity for the duration of each sampling day (i.e. 24 hours).
Sponsors
University of Western Australia
Eligibility
Sex/Gender
All
Age
No minimum to 3 Days
Healthy volunteers
Yes
Inclusion criteria
1. <28 weeks postmenstrual age 2. 28-<32 weeks postmenstrual age 3. 32-<36 weeks postmenstrual age 4. 39-41 weeks postmenstrual age
Exclusion criteria
Any abnormality of the central nervous system Any congenital abnormality requiring surgery in the first 4 months Any jaundice with SBR>400 mmol/L or requiring exchange transfusion Any hypoxic ischaemic encephalopathy (any grade) Intraventricular haemorrhage > Gr 2 10 minute apgar score of less than 5. Term infants with illness necessitating overnight admission to NICU Infants with mothers that took CNS active medication whilst pregnant Infants with mothers that partook in any substance abuse whilst pregnant Infants with mothers that have hypothyroidism or hyperthyroidism or any other condition that affects the HPA axis.
Outcome results
None listed