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de Kloet ER, Joëls M. The cortisol switch between vulnerability and resilience. Mol Psychiatry 2024; 29:20-34. [PMID: 36599967 DOI: 10.1038/s41380-022-01934-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 12/14/2022] [Accepted: 12/16/2022] [Indexed: 01/06/2023]
Abstract
In concert with neuropeptides and transmitters, the end products of the hypothalamus-pituitary-adrenal (HPA) axis, the glucocorticoid hormones cortisol and corticosterone (CORT), promote resilience: i.e., the ability to cope with threats, adversity, and trauma. To exert this protective action, CORT activates mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) that operate in a complementary manner -as an on/off switch- to coordinate circadian events, stress-coping, and adaptation. The evolutionary older limbic MR facilitates contextual memory retrieval and supports an on-switch in the selection of stress-coping styles at a low cost. The rise in circulating CORT concentration after stress subsequently activates a GR-mediated off-switch underlying recovery of homeostasis by providing the energy for restraining the primary stress reactions and promoting cognitive control over emotional reactivity. GR activation facilitates contextual memory storage of the experience to enable future stress-coping. Such complementary MR-GR-mediated actions involve rapid non-genomic and slower gene-mediated mechanisms; they are time-dependent, conditional, and sexually dimorphic, and depend on genetic background and prior experience. If coping fails, GR activation impairs cognitive control and promotes emotional arousal which eventually may compromise resilience. Such breakdown of resilience involves a transition to a chronic stress construct, where information processing is crashed; it leads to an imbalanced MR-GR switch and hence increased vulnerability. Novel MR-GR modulators are becoming available that may reset a dysregulated stress response system to reinstate the cognitive flexibility required for resilience.
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Affiliation(s)
- E Ronald de Kloet
- Division of Endocrinology, Department of Internal Medicine, Leiden University Medical Center, Leiden University, Leiden, The Netherlands.
- Leiden/Amsterdam Center of Drug Research, Leiden University, Leiden, The Netherlands.
| | - Marian Joëls
- Dept. Translational Neuroscience, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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2
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Nguyen VT, Fields CJ, Ashley NT. Temporal dynamics of pro-inflammatory cytokines and serum corticosterone following acute sleep fragmentation in male mice. PLoS One 2023; 18:e0288889. [PMID: 38096187 PMCID: PMC10721077 DOI: 10.1371/journal.pone.0288889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 11/28/2023] [Indexed: 12/17/2023] Open
Abstract
Obstructive sleep apnea is increasing worldwide, leading to disordered sleep patterns and inflammatory responses in brain and peripheral tissues that predispose individuals to chronic disease. Pro-inflammatory cytokines activate the inflammatory response and are normally regulated by glucocorticoids secreted from adrenal glands. However, the temporal dynamics of inflammatory responses and hypothalamic-pituitary-adrenal (HPA) axis activation in relation to acute sleep fragmentation (ASF) are undescribed. Male C57BL/6J mice were exposed to ASF or control conditions (no ASF) over specified intervals (1, 2, 6, or 24 h) and cytokine gene expression (IL-1β, TNF-α) in brain and peripheral tissues as well as serum glucocorticoid and interleukin-6 (IL-6) concentration were assessed. The HPA axis was rapidly activated, leading to elevated serum corticosterone from 1-24 h of ASF compared with controls. This activation was followed by elevated serum IL-6 concentration from 6-24 h of ASF. The tissue to first exhibit increased pro-inflammatory gene expression from ASF was heart (1 h of ASF). In contrast, pro-inflammatory gene expression was suppressed in hypothalamus from 1 h of ASF, but elevated at 6 h. Because the HPA axis was activated throughout ASF, this suggests that brain, but not peripheral, pro-inflammatory responses were rapidly inhibited by glucocorticoid immunosuppression.
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Affiliation(s)
- Van Thuan Nguyen
- Department of Biology, Western Kentucky University, Bowling Green, Kentucky, United States of America
| | - Cameron J. Fields
- Department of Biology, Western Kentucky University, Bowling Green, Kentucky, United States of America
| | - Noah T. Ashley
- Department of Biology, Western Kentucky University, Bowling Green, Kentucky, United States of America
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3
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Roberts LD, Hornsby AK, Thomas A, Sassi M, Kinzett A, Hsiao N, David BR, Good M, Wells T, Davies JS. The 5:2 diet does not increase adult hippocampal neurogenesis or enhance spatial memory in mice. EMBO Rep 2023; 24:e57269. [PMID: 37987211 DOI: 10.15252/embr.202357269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 10/23/2023] [Accepted: 10/30/2023] [Indexed: 11/22/2023] Open
Abstract
New neurones are generated throughout life in the mammalian brain in a process known as adult hippocampal neurogenesis (AHN). Since this phenomenon grants a high degree of neuroplasticity influencing learning and memory, identifying factors that regulate AHN may be important for ameliorating age-related cognitive decline. Calorie restriction (CR) has been shown to enhance AHN and improve memory, mediated by the stomach hormone, ghrelin. Intermittent fasting (IF), a dietary strategy offering more flexibility than conventional CR, has also been shown to promote aspects of AHN. The 5:2 diet is a popular form of IF; however, its effects on AHN are not well characterised. To address this, we quantified AHN in adolescent and adult wild-type and ghrelin-receptor-deficient mice following 6 weeks on a 5:2 diet. We report an age-related decline in neurogenic processes. However, the 5:2 diet does not increase AHN nor enhance memory performance, suggesting that this specific form of IF is ineffective in promoting brain plasticity to support learning.
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Affiliation(s)
- Luke D Roberts
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | | | - Alanna Thomas
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Martina Sassi
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Aimee Kinzett
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Nathan Hsiao
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Bethan R David
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Mark Good
- School of Psychology, Cardiff University, Cardiff, UK
| | - Timothy Wells
- School of Biosciences, Cardiff University, Cardiff, UK
| | - Jeffrey S Davies
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
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4
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Nguyen VT, Fields CJ, Ashley NT. Inflammation from Sleep Fragmentation Starts in the Periphery Rather than Brain in Male Mice. RESEARCH SQUARE 2023:rs.3.rs-2544592. [PMID: 36824854 PMCID: PMC9949171 DOI: 10.21203/rs.3.rs-2544592/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Obstructive sleep apnea is increasing worldwide, leading to disordered sleep patterns and inflammatory responses in brain and peripheral tissues that predispose individuals to chronic disease. Pro-inflammatory cytokines activate the inflammatory response and are normally regulated by glucocorticoids secreted from adrenal glands. However, the temporal dynamics of inflammatory responses and hypothalamic-pituitary-adrenal (HPA) axis activation in relation to acute sleep fragmentation (ASF) are undescribed. Male C57BL/6J mice were exposed to ASF or control conditions (no ASF) over specified intervals (1, 2, 6, and 24 h) and cytokine gene expression (IL-1beta, TNF-alpha) in brain and peripheral tissues as well as serum glucocorticoid and interleukin-6 (IL-6) concentration were assessed. The HPA axis was rapidly activated, leading to elevated serum corticosterone from 1-24 h of ASF compared with controls. This activation was followed by elevated serum IL-6 concentration from 6-24 h of ASF. The tissue to first exhibit increased pro-inflammatory gene expression from ASF was heart (1 h of ASF). In contrast, pro-inflammatory gene expression was suppressed in hypothalamus after 1 h of ASF, but elevated after 6 h. Because the HPA axis was activated throughout ASF, this suggests that brain, but not peripheral, pro-inflammatory responses were rapidly inhibited by glucocorticoid immunosuppression.
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Schwabe L, Hermans EJ, Joëls M, Roozendaal B. Mechanisms of memory under stress. Neuron 2022; 110:1450-1467. [PMID: 35316661 DOI: 10.1016/j.neuron.2022.02.020] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/22/2022] [Accepted: 02/22/2022] [Indexed: 12/11/2022]
Abstract
It is well established that stress has a major impact on memory, driven by the concerted action of various stress mediators on the brain. Recent years, however, have seen considerable advances in our understanding of the cellular, neural network, and cognitive mechanisms through which stress alters memory. These novel insights highlight the intricate interplay of multiple stress mediators, including-beyond corticosteroids, catecholamines, and peptides-for instance, endocannabinoids, which results in time-dependent shifts in large-scale neural networks. Such stress-induced network shifts enable highly specific memories of the stressful experience in the long run at the cost of transient impairments in mnemonic flexibility during and shortly after a stressful event. Based on these recent discoveries, we provide a new integrative framework that links the cellular, systems, and cognitive mechanisms underlying acute stress effects on memory processes and points to potential targets for treating aberrant memory in stress-related mental disorders.
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Affiliation(s)
- Lars Schwabe
- Department of Cognitive Psychology, Universität Hamburg, Hamburg, Germany.
| | - Erno J Hermans
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands; Department of Cognitive Neuroscience, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Marian Joëls
- University Medical Center Groningen, University of Groningen, Groningen, the Netherlands; UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands
| | - Benno Roozendaal
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands; Department of Cognitive Neuroscience, Radboud University Medical Center, Nijmegen, the Netherlands
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Karst H, den Boon FS, Vervoort N, Adrian M, Kapitein LC, Joëls M. Non-genomic steroid signaling through the mineralocorticoid receptor: Involvement of a membrane-associated receptor? Mol Cell Endocrinol 2022; 541:111501. [PMID: 34740745 DOI: 10.1016/j.mce.2021.111501] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 10/05/2021] [Accepted: 10/27/2021] [Indexed: 12/25/2022]
Abstract
Corticosteroid receptors in the mammalian brain mediate genomic as well as non-genomic actions. Although receptors mediating genomic actions were already cloned 35 years ago, it remains unclear whether the same molecules are responsible for the non-genomic actions or that the latter involve a separate class of receptors. Here we focus on one type of corticosteroid receptors, i.e. the mineralocorticoid receptor (MR). We summarize some of the known properties and the current insight in the localization of the MR in peripheral cells and neurons, especially in relation to non-genomic signaling. Previous studies from our own and other labs provided evidence that MRs mediating non-genomic actions are identical to the ones involved in genomic signaling, but may be translocated to the plasma cell membrane instead of the nucleus. With fixed cell imaging and live cell imaging techniques we tried to visualize these presumed membrane-associated MRs, using antibodies or overexpression of MR-GFP in COS7 and hippocampal cultured neurons. Despite the physiological evidence for MR location in or close to the cell membrane, we could not convincingly visualize membrane localization of endogenous MRs or GFP-MR molecules. However, we did find punctae of labeled antibodies intracellularly, which might indicate transactivating spots of MR near the membrane. We also found some evidence for trafficking of MR via beta-arrestins. In beta-arrestin knockout mice, we didn't observe metaplasticity in the basolateral amygdala anymore, indicating that internalization of MRs could play a role during corticosterone activation. Furthermore, we speculate that membrane-associated MRs could act indirectly via activating other membrane located structures like e.g. GPER and/or receptor tyrosine kinases.
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Affiliation(s)
- Henk Karst
- Dept Translational Neuroscience, University Medical Center Utrecht, Utrecht University, the Netherlands.
| | - Femke S den Boon
- Dept Translational Neuroscience, University Medical Center Utrecht, Utrecht University, the Netherlands
| | - Niek Vervoort
- University Utrecht, Faculty of Science, Division of Cell Biology, Utrecht, the Netherlands
| | - Max Adrian
- University Utrecht, Faculty of Science, Division of Cell Biology, Utrecht, the Netherlands
| | - Lukas C Kapitein
- University Utrecht, Faculty of Science, Division of Cell Biology, Utrecht, the Netherlands
| | - Marian Joëls
- Dept Translational Neuroscience, University Medical Center Utrecht, Utrecht University, the Netherlands; University Medical Center Groningen, University of Groningen, the Netherlands
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Renormalizing synapses in sleep: The clock is ticking. Biochem Pharmacol 2021; 191:114533. [PMID: 33771494 DOI: 10.1016/j.bcp.2021.114533] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 12/11/2022]
Abstract
Sleep has been hypothesized to renormalize synapses potentiated in wakefulness. This is proposed to lead to a net reduction in synaptic strength after sleep in brain areas like the cortex and hippocampus. Biological clocks, however, exert independent effects on these synapses that may explain some of the reported differences after wake and sleep. These include changes in synaptic morphology, molecules and efficacy. In this commentary, I discuss why no firm conclusions should be drawn concerning the role of sleep in synaptic renormalization until the role of circadian rhythms are isolated and determined.
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Jaszczyk A, Juszczak GR. Glucocorticoids, metabolism and brain activity. Neurosci Biobehav Rev 2021; 126:113-145. [PMID: 33727030 DOI: 10.1016/j.neubiorev.2021.03.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 03/04/2021] [Accepted: 03/07/2021] [Indexed: 12/17/2022]
Abstract
The review integrates different experimental approaches including biochemistry, c-Fos expression, microdialysis (glutamate, GABA, noradrenaline and serotonin), electrophysiology and fMRI to better understand the effect of elevated level of glucocorticoids on the brain activity and metabolism. The available data indicate that glucocorticoids alter the dynamics of neuronal activity leading to context-specific changes including both excitation and inhibition and these effects are expected to support the task-related responses. Glucocorticoids also lead to diversification of available sources of energy due to elevated levels of glucose, lactate, pyruvate, mannose and hydroxybutyrate (ketone bodies), which can be used to fuel brain, and facilitate storage and utilization of brain carbohydrate reserves formed by glycogen. However, the mismatch between carbohydrate supply and utilization that is most likely to occur in situations not requiring energy-consuming activities lead to metabolic stress due to elevated brain levels of glucose. Excessive doses of glucocorticoids also impair the production of energy (ATP) and mitochondrial oxidation. Therefore, glucocorticoids have both adaptive and maladaptive effects consistently with the concept of allostatic load and overload.
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Affiliation(s)
- Aneta Jaszczyk
- Department of Animal Behavior and Welfare, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, 05-552 Jastrzebiec, 36a Postepu str., Poland
| | - Grzegorz R Juszczak
- Department of Animal Behavior and Welfare, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, 05-552 Jastrzebiec, 36a Postepu str., Poland.
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Kalafatakis K, Russell GM, Ferguson SG, Grabski M, Harmer CJ, Munafò MR, Marchant N, Wilson A, Brooks JC, Thakrar J, Murphy P, Thai NJ, Lightman SL. Glucocorticoid ultradian rhythmicity differentially regulates mood and resting state networks in the human brain: A randomised controlled clinical trial. Psychoneuroendocrinology 2021; 124:105096. [PMID: 33296841 PMCID: PMC7895801 DOI: 10.1016/j.psyneuen.2020.105096] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 10/23/2020] [Accepted: 11/26/2020] [Indexed: 12/17/2022]
Abstract
Adrenal glucocorticoid secretion into the systematic circulation is characterised by a complex rhythm, composed of the diurnal variation, formed by changes in pulse amplitude of an underlying ultradian rhythm of short duration hormonal pulses. To elucidate the potential neurobiological significance of glucocorticoid pulsatility in man, we have conducted a randomised, double-blind, placebo-controlled, three-way crossover clinical trial on 15 healthy volunteers, investigating the impact of different glucocorticoid rhythms on measures of mood and neural activity under resting conditions by recruiting functional neuroimaging, computerised behavioural tests and ecological momentary assessments. Endogenous glucocorticoid biosynthesis was pharmacologically suppressed, and plasma levels of corticosteroid restored by hydrocortisone replacement in three different regimes, either mimicking the normal ultradian and circadian profile of the hormone, or retaining the normal circadian but abolishing the ultradian rhythm of the hormone, or by our current best oral replacement regime which results in a suboptimal circadian and ultradian rhythm. Our results indicate that changes in the temporal mode of glucocorticoid replacement impact (i) the morning levels of self-perceived vigour, fatigue and concentration, (ii) the diurnal pattern of mood variation, (iii) the within-network functional connectivity of various large-scale resting state networks of the human brain, (iv) the functional connectivity of the default-mode, salience and executive control networks with glucocorticoid-sensitive nodes of the corticolimbic system, and (v) the functional relationship between mood variation and underlying neural networks. The findings indicate that the pattern of the ultradian glucocorticoid rhythm could affect cognitive psychophysiology under non-stressful conditions and opens new pathways for our understanding on the neuropsychological effects of cortisol pulsatility with relevance to the goal of optimising glucocorticoid replacement strategies.
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Affiliation(s)
- Konstantinos Kalafatakis
- Laboratories of Integrative Neuroscience and Endocrinology, School of Clinical Sciences, University of Bristol, BS1 3NY Bristol, United Kingdom; Clinical Research and Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, BS2 8DX Bristol, United Kingdom; Royal Bristol Infirmary, University Hospitals Bristol NHS Foundation Trust, BS2 8HW Bristol, United Kingdom.
| | - Georgina M Russell
- Laboratories of Integrative Neuroscience and Endocrinology, School of Clinical Sciences, University of Bristol, BS1 3NY Bristol, United Kingdom; Royal Bristol Infirmary, University Hospitals Bristol NHS Foundation Trust, BS2 8HW Bristol, United Kingdom
| | - Stuart G Ferguson
- School of Medicine, University of Tasmania, Hobart, TAS 7000, Australia
| | - Meryem Grabski
- Clinical Psychopharmacology Unit, Division of Psychology and Language Sciences, University College London, WC1E 6BT London, United Kingdom; MRC Integrative Epidemiology Unit, School of Psychological Science, University of Bristol, BS8 1TU Bristol, United Kingdom
| | - Catherine J Harmer
- Department of Psychiatry, Oxford University and Oxford Health NHS Foundation Trust, OX3 7JX Oxford, United Kingdom
| | - Marcus R Munafò
- MRC Integrative Epidemiology Unit, School of Psychological Science, University of Bristol, BS8 1TU Bristol, United Kingdom
| | - Nicola Marchant
- Laboratories of Integrative Neuroscience and Endocrinology, School of Clinical Sciences, University of Bristol, BS1 3NY Bristol, United Kingdom; Royal Bristol Infirmary, University Hospitals Bristol NHS Foundation Trust, BS2 8HW Bristol, United Kingdom
| | - Aileen Wilson
- Clinical Research and Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, BS2 8DX Bristol, United Kingdom
| | - Jonathan C Brooks
- Clinical Research and Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, BS2 8DX Bristol, United Kingdom
| | - Jamini Thakrar
- Laboratories of Integrative Neuroscience and Endocrinology, School of Clinical Sciences, University of Bristol, BS1 3NY Bristol, United Kingdom; Clinical Research and Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, BS2 8DX Bristol, United Kingdom; Royal Bristol Infirmary, University Hospitals Bristol NHS Foundation Trust, BS2 8HW Bristol, United Kingdom
| | - Patrick Murphy
- Laboratories of Integrative Neuroscience and Endocrinology, School of Clinical Sciences, University of Bristol, BS1 3NY Bristol, United Kingdom; Royal Bristol Infirmary, University Hospitals Bristol NHS Foundation Trust, BS2 8HW Bristol, United Kingdom
| | - Ngoc J Thai
- Clinical Research and Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, BS2 8DX Bristol, United Kingdom
| | - Stafford L Lightman
- Laboratories of Integrative Neuroscience and Endocrinology, School of Clinical Sciences, University of Bristol, BS1 3NY Bristol, United Kingdom; Royal Bristol Infirmary, University Hospitals Bristol NHS Foundation Trust, BS2 8HW Bristol, United Kingdom
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Lightman SL, Birnie MT, Conway-Campbell BL. Dynamics of ACTH and Cortisol Secretion and Implications for Disease. Endocr Rev 2020; 41:bnaa002. [PMID: 32060528 PMCID: PMC7240781 DOI: 10.1210/endrev/bnaa002] [Citation(s) in RCA: 135] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 02/13/2020] [Indexed: 12/20/2022]
Abstract
The past decade has seen several critical advances in our understanding of hypothalamic-pituitary-adrenal (HPA) axis regulation. Homeostatic physiological circuits need to integrate multiple internal and external stimuli and provide a dynamic output appropriate for the response parameters of their target tissues. The HPA axis is an example of such a homeostatic system. Recent studies have shown that circadian rhythmicity of the major output of this system-the adrenal glucocorticoid hormones corticosterone in rodent and predominately cortisol in man-comprises varying amplitude pulses that exist due to a subhypothalamic pulse generator. Oscillating endogenous glucocorticoid signals interact with regulatory systems within individual parts of the axis including the adrenal gland itself, where a regulatory network can further modify the pulsatile release of hormone. The HPA axis output is in the form of a dynamic oscillating glucocorticoid signal that needs to be decoded at the cellular level. If the pulsatile signal is abolished by the administration of a long-acting synthetic glucocorticoid, the resulting disruption in physiological regulation has the potential to negatively impact many glucocorticoid-dependent bodily systems. Even subtle alterations to the dynamics of the system, during chronic stress or certain disease states, can potentially result in changes in functional output of multiple cells and tissues throughout the body, altering metabolic processes, behavior, affective state, and cognitive function in susceptible individuals. The recent development of a novel chronotherapy, which can deliver both circadian and ultradian patterns, provides great promise for patients on glucocorticoid treatment.
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Affiliation(s)
- Stafford L Lightman
- Translational Health Science, Bristol Medical School, University of Bristol, Bristol, UK
| | - Matthew T Birnie
- Translational Health Science, Bristol Medical School, University of Bristol, Bristol, UK
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