Autoantibodies to Selenoprotein P in Patients with Chronic Fatigue Syndrome Suggest Selenium Transport Impairment and Acquired Resistance to Thyroid Hormone

Abstract:

Chronic Fatigue Syndrome (CFS) presents with symptoms similar to hypothyroidism, including mental and physical fatigue, poor sleep, depression, and anxiety. However, the typical thyroid hormone (TH) profile of elevated thyrotropin (TSH) and low thyroxine (T4) is not observed. Recently, autoantibodies to the selenium transporter SELENOP (SELENOP-aAb) have been identified in Hashimoto’s thyroiditis and shown to impair selenium transport and selenoprotein expression. We hypothesized that SELENOP-aAb are prevalent in CFS and impair TH metabolism.

Selenium status in CFS (n=167) was compared to that of healthy controls (n=545). Two additional small groups were included, namely patients with fibromyalgia (FM; n=39), a disease often comorbid with CFS, and patients with post-COVID condition (n=24). The serum/plasma Se biomarkers total Se, glutathione peroxidase (GPx3) and SELENOP levels showed linear correlations without reaching saturation, indicative of Se deficiency. TSH and total T4 levels fitted within normal ranges, but relative total T3 (%TT3) was low, and relative rT3 (%rT3) was elevated in CFS. SELENOP-aAb prevalence was 9.6-15.6% in CFS versus 0.9-2.0% in controls, depending on cut-off for positivity.

An impairment of Se transport in SELENOP-aAb positive CFS patients is suggested by the lack of correlation between total Se and GPx3 activity. The same patients present with disturbed TH parameters, including low deiodinase (DIO) activity (SPINA-GD index) and particularly low urinary iodine as compared to controls (43.2 (16.0) vs. 89.0 (54.9) µg/L, P<0.001), indicating that SELENOP-aAb affect TH deiodination and iodine excretion.

We conclude that a considerable subset of CFS patients express SELENOP-aAb that disturb Se transport and cause low GPx3 and DIO activities. Hereby, TH deiodination decreases as an acquired condition that is not readily reflected by TSH or T4 in blood. This hypothesis opens new explanations and therapeutic options for SELENOP-aAb positive CFS and, perhaps, post-COVID condition patients, but requires additional clinical evidence from intervention trials.

Source: Sun, Qian and Oltra, Elisa and Dijck-Brouwer, D. A. Janneke and Chillon, Thilo Samson and Seemann, Petra and Asaad, Sabrina and Demircan, Kamil and Espejo-Oltra, José Andrés and Sánchez-Fito, Teresa and Martin-Martinez, Eva and Minich, Waldemar B. and Muskiet, Frits A. J. and Schomburg, Lutz, Autoantibodies to Selenoprotein P in Patients with Chronic Fatigue Syndrome Suggest Selenium Transport Impairment and Acquired Resistance to Thyroid Hormone. Available at SSRN: https://ssrn.com/abstract=4332223 or http://dx.doi.org/10.2139/ssrn.4332223 (Full text available as PDF file)

Hypothesis: Mechanisms That Prevent Recovery in Prolonged ICU Patients Also Underlie Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Here the hypothesis is advanced that maladaptive mechanisms that prevent recovery in some intensive care unit (ICU) patients may also underlie Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Specifically, these mechanisms are: (a) suppression of the pituitary gland’s pulsatile secretion of tropic hormones, and (b) a “vicious circle” between inflammation, oxidative and nitrosative stress (O&NS), and low thyroid hormone function. This hypothesis should be investigated through collaborative research projects.

Introduction:

Critical illness refers to the physiological response to virtually any severe injury or infection, such as sepsis, liver disease, HIV infection, head injury, pancreatitis, burns, cardiac surgery, etc. (1). Researchers make a distinction between the acute phase of critical illness—in the first hours or days following severe trauma or infection; and the chronic or prolonged phase—in the case of patients that survive the acute phase but for unknown reasons do not start recovering and continue to require intensive care (i.e., “chronic ICU patients”). Independent of the nature of the critical illness, the acute phase is associated with an excessive response of pro-inflammatory cytokines (2) and is characterized by a uniform dysregulation of the endocrine axes (3). In prolonged critical illness, this dysregulation is maintained even once the initial inflammatory surge has settled (4). Regardless of the initial injury or infection, patients that suffer from prolonged critical illness experience profound muscular weakness, cognitive impairment, loss of lean body mass, pain, increased vulnerability to infection, skin breakdown, etc. (1, 5, 6). Whereas, the acute phase is considered to be an adaptive response to the severe stress of injury or infection (shifting energy and resources to essential organs and repair), the physiological mechanisms in the prolonged phase are now increasingly considered to be maladaptive responses to the stress of severe injury or infection, hindering recovery (7–10). Some have also suggested that the non-recovery from endocrine disturbances could explain the development of “post-intensive care syndrome” (PICS) (11); i.e., “the cognitive, psychiatric and/or physical disability after treatment in ICUs” (12, 13).

Source: Dominic Stanculescu, Lars Larsson and Jonas Bergquist. Hypothesis: Mechanisms That Prevent Recovery in Prolonged ICU Patients Also Underlie Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). Front. Med., 28 January 2021 | https://doi.org/10.3389/fmed.2021.628029 https://www.frontiersin.org/articles/10.3389/fmed.2021.628029/full (Full text)

Endocrinopathy in the differential diagnosis of chronic fatigue syndrome

Abstract:

Fatigue is a frequent and sometimes dominant symptom of some endocrinopathies. It may be associated with other symptoms which are included among the criteria of the chronic fatigue syndrome. These units are not always quite distinct and frequently endocrine diseases and chronic fatigue syndrome (CFS) overlap. From this ensue differential diagnostic problems and ideas on possible causal relations.

The authors concentrate in particular on autoimmune endocrinopathies and the polyglandular autoimmune syndrome (APS) with emphasis on the necessity of an accurate endocrinological diagnosis, where is some patients with suspected CFS a defined endocrinopathy was revealed.

Attention will be also paid to recent views on the possible participation of disorders of the hypothalamus-pituitary-adrenal axis in the etiopathogenesis of CFS where endocrine and immune regulation overlap and condition each other.

 

Source: Sterzl I, Zamrazil V. Endocrinopathy in the differential diagnosis of chronic fatigue syndrome. Vnitr Lek. 1996 Sep;42(9):624-6. [Article in Czech] http://www.ncbi.nlm.nih.gov/pubmed/8984770