Category: Endocrine System

The HPA axis and the genesis of chronic fatigue syndrome

Abstract:

Many studies of patients with long-standing chronic fatigue syndrome (CFS) have found alterations to the hypothalamo-pituitary-adrenal (HPA) axis, including mild hypocortisolism, heightened negative feedback and blunted responses to challenge. However, recent prospective studies of high-risk cohorts suggest that there are no HPA axis changes present during the early stages of the genesis of fatiguing illnesses. Moreover, HPA axis changes can be reversed by modifying behavioural features of the illness, such as inactivity, deconditioning and sleep disturbance. Nevertheless, raising levels of cortisol pharmacologically can temporarily alleviate symptoms of fatigue. This article presents the case that there is no specific change to the HPA axis in CFS and that the observed changes are of multifactorial aetiology, with some factors occurring as a consequence of the illness. Nevertheless, the HPA axis might play a role in exacerbating or perpetuating symptoms late on in the course of the illness.

 

Source: Cleare AJ. The HPA axis and the genesis of chronic fatigue syndrome. Trends Endocrinol Metab. 2004 Mar;15(2):55-9. http://www.ncbi.nlm.nih.gov/pubmed/15036250

 

Salivary cortisol response to awakening in chronic fatigue syndrome

Abstract:

BACKGROUND: There is accumulating evidence of hypothalamic-pituitary-adrenal (HPA) axis disturbances in chronic fatigue syndrome (CFS). The salivary cortisol response to awakening has been described recently as a non-invasive test of the capacity of the HPA axis to respond to stress. The results of this test correlate closely with those of more invasive dynamic tests reported in the literature; furthermore, it can be undertaken in a naturalistic setting.

AIMS: To assess the HPA axis using the salivary cortisol response to awakening in CFS.

METHOD: We measured salivary cortisol upon awakening and 10, 20, 30 and 60 min afterwards in 56 patients with CFS and 35 healthy volunteers.

RESULTS: Patients had a lower cortisol response to awakening, measured by the area under the curve.

CONCLUSIONS: This naturalistic test of the HPA axis response to stress showed impaired HPA axis function in CFS.

 

Source: Roberts AD, Wessely S, Chalder T, Papadopoulos A, Cleare AJ. Salivary cortisol response to awakening in chronic fatigue syndrome. Br J Psychiatry. 2004 Feb;184:136-41. http://bjp.rcpsych.org/content/184/2/136.long (Full article)

 

Glucocorticoids and glucocorticoid receptors: mediators of fatigue?

Abstract:

Fatigue is a common problem; when chronic and disabling, subjects can be categorized as having chronic fatigue syndrome (CFS). Whilst it is most likely a multifactorial condition of biopsychosocial origin, the nature of the pathophysiological component remains unclear. There has been a wealth of interest in the possible hypothalamo-pituitary-adrenal (HPA) axis dysfunction in CFS, and whether such changes may mediate fatigue.

On balance, there appears to be reduced cortisol output in a proportion of patients, together with heightened negative feedback and glucocorticoid receptor function. There is evidence for impaired adrenocorticotropic hormone (ACTH) and cortisol responses to a variety of challenges. However, there is no evidence for a specific or uniform dysfunction of the HPA axis.

Evidence that these changes may be related to symptom production comes from randomized controlled trials of glucocorticoid replacement therapy, which have shown improvements in fatigue and disability. Given the many factors that may impinge on the HPA axis in CFS, such as inactivity, sleep disturbance, psychiatric comorbidity, medication and ongoing stress, it seems likely that there is not a single or specific change to the HPA axis in CFS and that the observed HPA axis disturbances are of multifactorial etiology. This is further supported by a comparison of neuroendocrine findings in other conditions in which fatigue is prominent, showing both similarities and differences with the pattern in CFS.

 

Source: Cleare AJ. Glucocorticoids and glucocorticoid receptors: mediators of fatigue? Acta Neuropsychiatr. 2003 Dec;15(6):341-53. doi: 10.1046/j.1601-5215.2003.00050.x. http://www.ncbi.nlm.nih.gov/pubmed/26983770

 

Chronic fatigue syndrome: an endocrine disease off limits for endocrinologists?

Abstract:

Endocrinologists were not included in the multidisciplinary working groups that prepared two recent reports on chronic fatigue syndrome, despite its unequalled clinical overlap with Addison’s disease, which is a classic endocrine disorder. The failure to include at least one endocrinologist in those panels may explain why in their extensive reports there is not a single word about the 42 clinical features that chronic fatigue syndrome shares with Addison’s disease, including all the signs and symptoms listed in the case definition of this syndrome.

Comment in: Dr Baschetti rides/writes again. [Eur J Clin Invest. 2004]

 

Source: Baschetti R. Chronic fatigue syndrome: an endocrine disease off limits for endocrinologists? Eur J Clin Invest. 2003 Dec;33(12):1029-31. http://www.ncbi.nlm.nih.gov/pubmed/14636284

 

Association between serotonin transporter gene polymorphism and chronic fatigue syndrome

Abstract:

Interaction between the hypothalamo-pituitary-adrenal axis and the serotonergic system is thought to be disrupted in chronic fatigue syndrome(CFS) patients. We examined a serotonin transporter (5-HTT) gene promoter polymorphism, which affects the transcriptional efficiency of 5-HTT, in 78 CFS patients using PCR amplification of the blood genomic DNA.

A significant increase of longer (L and XL) alleic variants was found in the CFS patients compared to the controls both by the genotype-wise and the allele-wise analyses (both p<0.05, by chi(2) test and Fisher’s exact test). Attenuated concentration of extracellular serotonin due to longer variants may cause higher susceptibility to CFS.

 

Source: Narita M, Nishigami N, Narita N, Yamaguti K, Okado N, Watanabe Y, Kuratsune H. Association between serotonin transporter gene polymorphism and chronic fatigue syndrome. Biochekm Biophys Res Commun. 2003 Nov 14;311(2):264-6. http://www.ncbi.nlm.nih.gov/pubmed/14592408

 

Enhanced glucocorticoid sensitivity in patients with chronic fatigue syndrome

Abstract:

OBJECTIVE: Alterations of the immune-neuroendocrine interplay have been described in chronic fatigue syndrome (CFS). Employing a recently developed method, the study set out to investigate whether patients with CFS have an altered sensitivity to glucocorticoids (GCs) when under stress.

METHODS: A total of 21 CFS patients and 20 healthy age- and gender-matched controls underwent a standardized psychosocial stress test (Trier Social Stress Test, TSST). Salivary and plasma cortisol levels were measured repeatedly following exposure to the stressor. GC sensitivity was assessed in vitro by dexamethasone inhibition of lipopolysaccharide-stimulated production of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNC-α).

RESULTS: Cortisol responses following the TSST did not differ significantly between CFS patients and healthy controls. GC sensitivity differed significantly between CFS patients and healthy controls, with CFS patients showing a greater sensitivity towards GCs (TNF-α: F 1/39 = 7.32, P = 0.01; IL-6: F 1/39 = 9.73, P = 0.004).

CONCLUSION: Consistent with recent evidence, CFS patients are characterized by an enhanced sensitivity to glucocorticoids. The implications for secondary processes, such as the regulatory influence of glucocorticoids on immune processes, are discussed.

 

Source: Gaab J, Rohleder N, Heitz V, Schad T, Engert V, Schürmeyer TH, Ehlert U. Enhanced glucocorticoid sensitivity in patients with chronic fatigue syndrome. Acta Neuropsychiatr. 2003 Aug;15(4):184-91. doi: 10.1034/j.1601-5215.2003.00033.x. http://www.ncbi.nlm.nih.gov/pubmed/26983566

 

Assessing chronic fatigue

Comment on: The head-up tilt test with haemodynamic instability score in diagnosing chronic fatigue syndrome. [QJM. 2003]

 

Naschitz et al.1 studied patients with chronic fatigue syndrome (CFS) in comparison with some controls ‘exhibiting shared clinical features with CFS’, namely, patients with non-CFS chronic fatigue, fibromyalgia, generalized anxiety disorder, and neurally mediated syncope. Considering that those controls were included in the study on the basis of the clinical overlap of their disorders with CFS, it is surprising that Naschitz et al. failed to include also patients with Addison’s disease, which resembles CFS far more closely than does any other medical condition.2

You can read the rest of this comment here: http://qjmed.oxfordjournals.org/content/96/6/454.long

 

Source: Baschetti R. Assessing chronic fatigue. QJM. 2003 Jun;96(6):454. http://qjmed.oxfordjournals.org/content/96/6/454.long (Full article)

 

The neuroendocrinology of chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is a common and disabling problem; although most likely of biopsychosocial origin, the nature of the pathophysiological components remains unclear. There has been a wealth of interest in the endocrinology of this condition, which will be reviewed in this article. Most studied has been the hypothalamic-pituitary-adrenal (HPA) axis; although the quality of many studies is poor, the overall balance of evidence points to reduced cortisol output in at least some patients, with some evidence that this is linked to symptom production or persistence.

There is evidence for heightened negative feedback and glucocorticoid receptor function and for impaired ACTH and cortisol responses to a variety of challenges. However, there is no evidence for a specific or uniform dysfunction of the HPA axis. Given the many factors that may impinge on the HPA axis in CFS, such as inactivity, sleep disturbance, psychiatric comorbidity, medication, and ongoing stress, it seems likely that HPA axis disturbance is heterogeneous and of multifactorial etiology in CFS. Studies assessing GH, dehydroepiandrostenedione and its sulfate, melatonin, leptin, and neuroendocrine-monoamine interactions are also reviewed.

There is some evidence from these studies to suggest alterations of dehydroepiandrostenedione sulfate function and abnormal serotonin function in CFS, but whether these changes are of functional importance remains unclear. To obtain a clearer assessment of the etiological and pathophysiological relevance of endocrine changes in CFS, it is suggested that more prospective cohort studies be undertaken in groups at high risk for CFS, that patients with CFS are followed up into recovery, and that multidimensional assessments are undertaken to unravel the influence of the various confounding factors on the observed endocrine changes in CFS.

 

Source: Cleare AJ. The neuroendocrinology of chronic fatigue syndrome. Endocr Rev. 2003 Apr;24(2):236-52. http://www.ncbi.nlm.nih.gov/pubmed/12700181

 

Assessment of cortisol response with low-dose and high-dose ACTH in patients with chronic fatigue syndrome and healthy comparison subjects

Abstract:

A reduced secretion of cortisol has been proposed as a possible explanation of the symptoms in chronic fatigue syndrome. However, the evidence of hypocortisolism in chronic fatigue syndrome is conflicting.

In order to simultaneously assess possible alterations in adrenocortical sensitivity and secretory adrenal reserve, the authors administered both low-dose and high-dose ACTH to a group of 18 chronic fatigue syndrome patients and 18 age- and gender-matched healthy comparison subjects.

No response differences for salivary and plasma cortisol were detectable after administration of either low-dose or high-dose ACTH, indicating that primary adrenal insufficiency is unlikely to play a significant role in the etiology of chronic fatigue syndrome.

 

Source: Gaab J, Hüster D, Peisen R, Engert V, Heitz V, Schad T, Schürmeyer T, Ehlert U. Assessment of cortisol response with low-dose and high-dose ACTH in patients with chronic fatigue syndrome and healthy comparison subjects. Psychosomatics. 2003 Mar-Apr;44(2):113-9. http://www.ncbi.nlm.nih.gov/pubmed/12618533

 

Type I interferons induce proteins susceptible to act as thyroid receptor (TR) corepressors and to signal the TR for destruction by the proteasome: possible etiology for unexplained chronic fatigue

Abstract:

In some patients complaining of chronic fatigue such as those suffering from the chronic fatigue syndrome (CFS), no underlying physical cause can be clearly identified and they typically present a normal thyroid function. Several studies indicate a dysregulation in the type I interferons (IFN-alpha/beta) pathway in CFS resulting in a sustained upregulation of 2(‘),5(‘)-oligoadenylate synthetases (2-5OAS). Likewise, patients treated with IFN-alpha/beta usually complain of severe fatigue as a limiting side effect.

Beside the 2-5OAS, IFN-alpha/beta induce also the expression of three closely related proteins of unknown function termed the 2-5OAS-like (2-5OASL) proteins. The amino acid sequences of the 2-5OASL proteins display 96% identity with the partial sequence of the thyroid receptor interacting protein (TRIP) 14, further contain two typical thyroid hormone receptor (TR) coregulator domains and feature two ubiquitin C-terminal domains.

From these observations, we raise the hypothesis that the 2-5OASL proteins are TRIPs capable of, respectively, repressing TR transactivation and/or signaling the receptor for destruction by the proteasome. Such molecular mechanisms could explain the development of a clinical hypothyroid state in presence of a normal thyroid function.

 

Source: Englebienne P, Verhas M, Herst CV, De Meirleir K. Type I interferons induce proteins susceptible to act as thyroid receptor (TR) corepressors and to signal the TR for destruction by the proteasome: possible etiology for unexplained chronic fatigue. Med Hypotheses. 2003 Feb;60(2):175-80. http://www.ncbi.nlm.nih.gov/pubmed/12606231