Bright, Orla
(2021)
Salivary Biomarkers of Health and Disease from Childhood to Older Age.
Master of Philosophy thesis, University of Liverpool.
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Abstract
BACKGROUND Cortisol, one of the body’s main stress hormones and is released in a pulsatile state following our body’s normal circadian rhythm. Cortisol is regulated by two isoforms of the enzyme 11β-hydroxysteroid dehydrogenase (11βHSD) type 1 and type 2. Deficiency of 11βHSD2 has been linked to increased blood pressure, evident in conditions such as apparent mineralocorticoid excess (AME) and Cushing’s Syndrome. Currently, salivary cortisol is used as a diagnostic and physiological biomarker in a range of different clinical and research studies Blood sampling is a painful and invasive procedure affecting cortisol levels, especially in children. For many years, blood has been one of the tools used to measure a range of hormones, but only recently have researchers taken notice of saliva. The aim of this research is to therefore investigate salivary cortisol and cortisone and to achieve this I will undertake a systematic review and the SMILE study. METHODS Undertake a PROSPERO registered systematic review to examine the relationship between salivary cortisol and cortisone and hypertension. Set up and recruit to an observational cohort study (SMILE) to determine normative values of salivary cortisol and cortisone in children and young people. Participants collected samples of their saliva as they initially woke up and throughout the waking hours of a day. These samples were sent for cortisol and cortisone analysis. RESULTS The systematic review only found 3 papers. Kidambi et Al found that late night salivary (p<0.01) and early morning cortisol (p<0.03) levels were higher in hypertensive patients compared to normotensive (PM salivary (1.2nmol/ vs 1.8 nmol/L) AM Salivary (11.2nmol/l vs 14.4nmol/l). Walker 2002 didn’t find any difference in concentrations of cortisol/ cortisone in normotensive and hypertensive patients at baseline and after administration of glycyrrhetinic acid. Similarly, Wirix et al. found that no significant differences in these parameters between hypertensive and normotensive children and salivary cortisol levels weren’t significantly associated with systolic or diastolic blood pressure SDS. Within SMILE, 54 participants, aged 5-18 years, 31 male (57.4%) and 23 females (42.6%), with a median age of 9 (range 12 years (5-17)) were recruited, to obtain 365 saliva samples. Both cortisol and cortisone exhibited a diurnal rhythm similar to that of serum. Cortisol mean concentration over 24 hours was 0.2 nmol/L (+/-4.225), median 1.4nmol. Cortisone mean concentration over 24 hours was 15.8 nmol/L (+/-12.83), median 11.5 nmol/L.
| Item Type: | Thesis (Master of Philosophy) |
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| Divisions: | Faculty of Health and Life Sciences Faculty of Health and Life Sciences > Institute of Life Courses and Medical Sciences Faculty of Health and Life Sciences > Institute of Life Courses and Medical Sciences > School of Medicine |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 08 Feb 2022 16:11 |
| Last Modified: | 18 Jan 2023 21:28 |
| DOI: | 10.17638/03138448 |
| Supervisors: |
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| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3138448 |
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