Category: Endocrine System

Glucocorticoid receptor polymorphisms and haplotypes associated with chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is a significant public health problem of unknown etiology, the pathophysiology has not been elucidated, and there are no characteristic physical signs or laboratory abnormalities. Some studies have indicated an association of CFS with deregulation of immune functions and hypothalamic-pituitary-adrenal (HPA) axis activity.

In this study, we examined the association of sequence variations in the glucocorticoid receptor gene (NR3C1) with CFS because NR3C1 is a major effector of the HPA axis. There were 137 study participants (40 with CFS, 55 with insufficient symptoms or fatigue, termed as ISF, and 42 non-fatigued controls) who were clinically evaluated and identified from the general population of Wichita, KS. Nine single nucleotide polymorphisms (SNPs) in NR3C1 were tested for association of polymorphisms and haplotypes with CFS.

We observed an association of multiple SNPs with chronic fatigue compared to non-fatigued (NF) subjects (P < 0.05) and found similar associations with quantitative assessments of functional impairment (by the SF-36), with fatigue (by the Multidimensional Fatigue Inventory) and with symptoms (assessed by the Centers for Disease Control Symptom Inventory).

Subjects homozygous for the major allele of all associated SNPs were at increased risk for CFS with odds ratios ranging from 2.61 (CI 1.05-6.45) to 3.00 (CI 1.12-8.05). Five SNPs, covering a region of approximately 80 kb, demonstrated high linkage disequilibrium (LD) in CFS, but LD gradually declined in ISF to NF subjects. Furthermore, haplotype analysis of the region in LD identified two associated haplotypes with opposite alleles: one protective and the other conferring risk of CFS.

These results demonstrate NR3C1 as a potential mediator of chronic fatigue, and implicate variations in the 5′ region of NR3C1 as a possible mechanism through which the alterations in HPA axis regulation and behavioural characteristics of CFS may manifest.

 

Source: Rajeevan MS, Smith AK, Dimulescu I, Unger ER, Vernon SD, Heim C, Reeves WC. Glucocorticoid receptor polymorphisms and haplotypes associated with chronic fatigue syndrome. Genes Brain Behav. 2007 Mar;6(2):167-76. http://onlinelibrary.wiley.com/doi/10.1111/j.1601-183X.2006.00244.x/full (Full article)

 

Reduced levels of oestrogen receptor beta mRNA in Swedish patients with chronic fatigue syndrome

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) is an illness with unknown aetiology and pathophysiology. The difference in incidence by sex observed for CFS indicates a role for oestrogen and oestrogen receptors in disease development. Furthermore, an immunomediated pathogenesis has been suggested for CFS, providing an additional connection to oestrogen, which displays immunomodular functions.

AIMS: To investigate a possible association of oestrogen receptor (ER) mRNAs and two ERbeta single-nucleotide polymorphisms (SNPs) with CFS.

METHODS: Messenger RNA levels of ERalpha, ERbeta wt and ERbeta cx were investigated in peripheral blood mononuclear cells from 30 patients with CFS and 36 healthy controls by quantitative real-time polymerase chain reaction. Two ERbeta SNPs were scored in the same material.

RESULTS: The CFS group showed significantly lower mRNA expression levels of ERbeta wt compared with the healthy control group. No differences were observed for ERalpha or ERbeta cx between patients and controls. There were no significant differences in frequency for the investigated ERbeta SNPs between cases and controls.

CONCLUSIONS: The reduced ERbeta wt expression level observed in this study is consistent with an immune-mediated pathogenesis of CFS. Additionally, the observation that ERbeta wt expression is decreased in CFS could provide an entry point to identify interesting, potentially disease-causing, candidate molecules for further study. A possible connection between oestrogen, oestrogen receptors and CFS should be evaluated further.

 

Source: Gräns H, Nilsson M, Dahlman-Wright K, Evengård B. Reduced levels of oestrogen receptor beta mRNA in Swedish patients with chronic fatigue syndrome. J Clin Pathol. 2007 Feb;60(2):195-8. Epub 2006 May 26. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1860629/

 

Chronic fatigue syndrome and high allostatic load

Abstract:

STUDY POPULATION: We examined the relationship between chronic fatigue syndrome (CFS) and allostatic load in a population-based, case-control study of 43 CFS patients and 60 nonfatigued, healthy controls from Wichita, KS, USA.

METHODS: An allostatic load index was computed for all study participants using available laboratory and clinical data, according to a standard algorithm for allostatic load. Logistic regression analysis was used to compute odds ratios (ORs) as estimates of relative risk in models that included adjustment for matching factors and education; 95% confidence intervals (CIs) were computed to estimate the precision of the ORs.

RESULTS: CFS patients were 1.9-times more likely to have a high allostatic load index than controls (95% CI = 0.75, 4.75) after adjusting for education level, in addition to matching factors. The strength of this association increased in a linear trend across categories of low, medium and high levels of allostatic load (p = 0.06).

CONCLUSION: CFS was associated with a high level of allostatic load. The three allostatic load components that best discriminated cases from controls were waist:hip ratio, aldosterone and urinary cortisol.

 

Source: Maloney EM, Gurbaxani BM, Jones JF, de Souza Coelho L, Pennachin C, Goertzel BN. Chronic fatigue syndrome and high allostatic load. Pharmacogenomics. 2006 Apr;7(3):467-73. https://www.ncbi.nlm.nih.gov/pubmed/16610956

 

Polymorphisms in genes regulating the HPA axis associated with empirically delineated classes of unexplained chronic fatigue

Abstract:

Chronic fatigue syndrome (CFS) is characterized by persistent or relapsing fatigue that is not alleviated by rest, causes substantial reduction in activities and is accompanied by a variety of symptoms. Its unknown etiology may reflect that CFS is heterogeneous. Latent class analyses of symptoms and physiological systems were used to delineate subgroups within a population-based sample of fatigued and nonfatigued subjects [1] . This study examined whether genetic differences underlie the individual subgroups of the latent class solution.

Polymorphisms in 11 candidate genes related to both hypothalamic-pituitary-adrenal (HPA) axis function and mood-related neurotransmitter systems were evaluated by comparing each of the five ill classes (Class 1, n = 33; Class 3, n = 22; Class 4, n = 22; Class 5, n = 17; Class 6, n = 11) of fatigued subjects with subjects defined as well (Class 2, n = 35). Of the five classes of subjects with unexplained fatigue, three classes were distinguished by gene polymorphsims involved in either HPA axis function or neurotransmitter systems, including proopiomelanocortin (POMC), nuclear receptor subfamily 3, group C, member 1 (NR3C1), monoamine oxidase A (MAOA), monoamine oxidase B (MAOB), and tryptophan hydroxylase 2 (TPH2). These data support the hypothesis that medically unexplained chronic fatigue is heterogeneous and presents preliminary evidence of the genetic mechanisms underlying some of the putative conditions.

 

Source: Smith AK, White PD, Aslakson E, Vollmer-Conna U, Rajeevan MS. Polymorphisms in genes regulating the HPA axis associated with empirically delineated classes of unexplained chronic fatigue. Pharmacogenomics. 2006 Apr;7(3):387-94. https://www.ncbi.nlm.nih.gov/pubmed/16610949

 

Diurnal excretion of urinary cortisol, cortisone, and cortisol metabolites in chronic fatigue syndrome

Abstract:

OBJECTIVE: The aim of this study was to obtain comprehensive information on basal hypothalamic-pituitary-adrenal (HPA) axis activity in chronic fatigue syndrome (CFS) patients who were not affected by medication or comorbid psychiatric disorder likely to influence the HPA axis.

METHOD: Steroid analysis of urine collections from 0600 to 2100 h at 3-h intervals in CFS patients and in controls.

RESULTS: Urinary free cortisol and cortisone concentrations showed a significant normal diurnal rhythm, but levels were lower across the cycle in CFS. In contrast, while urinary cortisol metabolites also showed a normal diurnal rhythm, levels were not significantly different between the CFS and controls at any time. Derived metabolite ratios were similar in both groups.

CONCLUSION: This study provides further evidence for reduced basal HPA axis function in patients with CFS, based on lower free cortisol and cortisone levels, but this is not corroborated by cortisol metabolite data. The difference between these measures cannot be explained by an altered timing of the diurnal rhythm.

Comment in: Comment on “diurnal excretion of urinary cortisol, cortisone, and cortisol metabolites in chronic fatigue syndrome”. [J Psychosom Res. 2006]

 

Source: Jerjes WK, Peters TJ, Taylor NF, Wood PJ, Wessely S, Cleare AJ. Diurnal excretion of urinary cortisol, cortisone, and cortisol metabolites in chronic fatigue syndrome. J Psychosom Res. 2006 Feb;60(2):145-53. https://www.ncbi.nlm.nih.gov/pubmed/16439267

 

Decreased dehydroepiandrosterone sulfate but normal insulin-like growth factor in chronic fatigue syndrome (CFS): relevance for the inflammatory response in CFS

Abstract:

There are a few reports that chronic fatigue syndrome (CFS) may be accompanied by changes in hormones, such as dehydroepiandrosterone (DHEA) and insulin-like growth factor (IGF1). This study examines the serum concentrations of DHEA-sulfate (DHEAS), IGF1 and IGF1 binding protein-3 (IGFBP3) in 20 patients with CFS and in 12 normal controls.

The IGFBP3/IGF1 ratio was computed as an index for IGF1 availability. We found significantly lower serum DHEAS concentrations in CFS, but no significant differences either in IGF1 or the IGFBP3/IGF1 ratio between CFS patients and normal controls. The decrease in serum DHEAS was highly sensitive and specific for CFS.

There were significant and positive correlations between serum DHEAS and serum zinc and the mitogen-induced expression of the CD69 molecule on CD3+CD8+ T cells (an indicator of early T cell activation). There was a significant and negative correlation between serum DHEAS and the increase in the serum alpha-2 protein fraction (an inflammatory marker). Serum IGF1, but not DHEAS, was significantly and inversely correlated to age.

The results show that CFS is accompanied by lowered levels of DHEAS and that the latter may play a role in the immune (defect in the early activation of T cells) and the inflammatory pathophysiology of CFS.

 

Source: Maes M, Mihaylova I, De Ruyter M. Decreased dehydroepiandrosterone sulfate but normal insulin-like growth factor in chronic fatigue syndrome (CFS): relevance for the inflammatory response in CFS. Decreased dehydroepiandrosterone sulfate but normal insulin-like growth factor in chronic fatigue syndrome (CFS): relevance for the inflammatory response in CFS. Neuro Endocrinol Lett. 2005 Oct;26(5):487-92. http://www.ncbi.nlm.nih.gov/pubmed/16264414

 

Chronic fatigue syndrome, exercise, cortisol and lymphadenopathy

Dear Sir,

As in the past [1], the effects of exercise in the treatment of chronic fatigue syndrome (CFS) are conflicting. Indeed, while Powell et al. [2], in 2004, reported that graded exercise was beneficial to CFS patients, Black et al. [3] have lately written that ‘overall mood, muscle pain intensity, and time spent each day with fatigue worsened following increased activity’ [3] in CFS patients, despite the fact that their increase in daily physical activity was rather moderate (28%) [3]. The virtually opposite effects of exercise in different groups of CFS patients [1–3] may reflect their different cortisol levels [1], which, just as occurred some years ago [1], continue to be contradictory. For example, Inder et al. [4], in March 2005, reported that cortisol levels were normal in their patients with CFS, whereas Segal et al. [5], in the same month, reported that their subjects with CFS had hypocortisolism.

Considering that most features of CFS, such as ‘debilitating fatigue, an abrupt onset precipitated by a stressor, feverishness, arthralgias, myalgias, adenopathy, postexertional fatigue, exacerbation of allergic responses, and disturbances in mood and sleep are all characteristic of glucocorticoid insufficiency’ [6], it is not surprising that hypocortisolism has been convincingly shown to be implicated in the pathophysiology of CFS [7]. Therefore, especially the postexertional fatigue caused by glucocorticoid insufficiency [6] strongly suggests that exercise could be of benefit to CFS patients with high [1] or normal cortisol levels [4], whereas it could be harmful to CFS patients with hypocortisolism [1, 5, 6]. Unfortunately, because of the misleading coexistence of quite different diagnostic criteria for CFS [1], it is difficult to predict the patients with CFS who are more likely to have hypocortisolism and which would worsen with exercise. However, it is arguable that the presence or absence of lymphadenopathy [8], which is a sign of hypocortisolism [6, 9] and is one of the 43 clinical features that CFS shares with Addison’s disease [10–12], could reliably discriminate CFS patients who may worsen with exercise from those who may improve with it. Indeed, lymphadenopathy, unlike other symptoms of CFS [11, 12], many of which are non-specific and can also be found in depression and other affective disorders [11, 12], is far from being common in physical diseases and is absent in psychiatric conditions.

You can read the rest of this comment here: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2796.2005.01526.x/full

 

Source: Baschetti R. Chronic fatigue syndrome, exercise, cortisol and lymphadenopathy. J Intern Med. 2005 Sep;258(3):291-2. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2796.2005.01526.x/full (Full article)

 

Diurnal patterns of salivary cortisol and cortisone output in chronic fatigue syndrome

Abstract:

BACKGROUND: The aim of the present study was to obtain a naturalistic measure of diurnal hypothalamic-pituitary-adrenal (HPA) axis output in CFS patients unaffected by medication or comorbid psychiatric disorder likely to influence the axis.

METHOD: Cortisol and cortisone levels were measured in saliva samples collected from 0600 h to 2100 h at 3-h intervals in CFS patients and healthy controls.

RESULTS: Mean cortisol and cortisone concentrations were significantly lower in patients than controls across the whole day, as were levels at each individual time point except 2100 h. Cosinor analysis showed a significant diurnal rhythm of cortisol and cortisone that was not phase-shifted in CFS compared to controls. However, there was a lower rhythm-adjusted mean and a lower amplitude in CFS patients. The cortisol/cortisone ratio showed no diurnal rhythm and did not differ between CFS subjects and controls.

LIMITATIONS: The sample size was relatively small, and drawn from specialist referral patients who had been ill for some time; generalisation of these results to other populations is therefore unwarranted.

CONCLUSION: The main findings of this study are to provide further evidence for reduced basal HPA axis function in at least some patients with CFS and to show for the first time that salivary cortisone is also reduced in CFS and has a diurnal rhythm similar to that of cortisol. We have also demonstrated that the cortisol/cortisone ratio remains unchanged in CFS, suggesting that increased conversion of cortisol to cortisone cannot account for the observed lowering of salivary cortisol.

 

Source: Jerjes WK, Cleare AJ, Wessely S, Wood PJ, Taylor NF. Diurnal patterns of salivary cortisol and cortisone output in chronic fatigue syndrome. J Affect Disord. 2005 Aug;87(2-3):299-304. http://www.ncbi.nlm.nih.gov/pubmed/15922454

 

Salivary cortisol as a predictor of postoperative fatigue

 Abstract:

OBJECTIVE: Some patients with chronic fatigue syndrome (CFS) exhibit low basal cortisol levels, but it is not known whether low cortisol is a cause of CFS, predates the onset of CFS symptoms, or is an epiphenomenon caused by the behavioral changes typical of CFS. Because elective surgery is one of the few predictable risk factors for chronic fatigue, in this study, we followed a cohort of surgery patients from before to 6 months after their operation to test these theories.

METHOD: One hundred sixty-one patients completed fatigue questionnaires and provided salivary cortisol samples before undergoing an elective inpatient surgical procedure, and then 2 days, 3 weeks, and 6 months afterward.

RESULTS: Controlling for relevant demographic and surgical variables and for preoperative fatigue, low preoperative cortisol did not predict postoperative fatigue severity on any occasion (p > .05). Similarly, there was no correlation between low postoperative cortisol and postoperative fatigue severity at 3 weeks or 6 months (p > .05). Although 16 patients met our case definition for “chronic fatigue” at the 6-month follow up, low preoperative and low postoperative cortisol did not significantly predict fatigue caseness (p > .05).

CONCLUSIONS: Any association between chronic fatigue and low cortisol would seem to develop after the onset of fatigue symptoms. Low cortisol is therefore unlikely to be the primary cause of chronic fatigue states.

 

Source: Rubin GJ, Hotopf M, Papadopoulos A, Cleare A. Salivary cortisol as a predictor of postoperative fatigue. Psychosom Med. 2005 May-Jun;67(3):441-7. http://www.ncbi.nlm.nih.gov/pubmed/15911908 

 

24-hour pituitary and adrenal hormone profiles in chronic fatigue syndrome

Abstract:

OBJECTIVES: Disturbances of neuroendocrine function, particularly the hypothalamo-pituitary-adrenal (HPA) axis, have been implicated in the pathophysiology of chronic fatigue syndrome (CFS). However, few studies have attempted to measure blood levels of pituitary or adrenal hormones across a whole 24-hour period in CFS, and those that did so have used infrequent sampling periods. Our aim was to assess 24-hour pituitary and adrenal function using frequent blood sampling.

METHODS: We recruited 15 medication-free patients with CFS without comorbid psychiatric disorder and 10 healthy control subjects. Blood samples were collected over 24 hours and assayed for cortisol, corticotropin (ACTH), growth hormone (GH), and prolactin (PRL) levels on an hourly basis during daytime hours (10 am to 10 pm) and every 15 minutes thereafter (10 pm to 10 am).

RESULTS: Repeated-measures analyses of variance were undertaken using hormone levels averaged over 2-hour blocks to smooth curves by reducing the influence of sample timing relative to secretory burst. For ACTH, there was both a main effect of group, suggesting reduced mean ACTH secretion in patients with CFS over the whole monitoring period, and a group-by-time interaction, suggesting a differential pattern of ACTH release. Post hoc analysis showed reduced ACTH levels in CFS during the 8 am to 10 am period. In contrast, there were no significant abnormalities in the levels of cortisol, GH, and PRL in patients with CFS over the full cycle compared with control subjects. Cosinor analysis found no differences in the cortisol circadian rhythm parameters, but the ACTH rhythm did differ, patients with CFS showing an earlier acrophase.

CONCLUSIONS: Patients with CFS demonstrated subtle alterations in HPA axis activity characterized by reduced ACTH over a full circadian cycle and reduced levels during the usual morning physiological peak ACTH secretion. This provides further evidence of subtle dysregulation of the HPA axis in CFS. Whether this dysregulation is a primary feature of the illness or instead represents a biologic effect secondary to having the illness itself remains unclear.

 

Source: Di Giorgio A, Hudson M, Jerjes W, Cleare AJ. 24-hour pituitary and adrenal hormone profiles in chronic fatigue syndrome. Psychosom Med. 2005 May-Jun;67(3):433-40. http://www.ncbi.nlm.nih.gov/pubmed/15911907