Thyroid Functioning and Fatigue in Women With Functional Somatic Syndromes - Role of Early Life Adversity

Assessing prefrontal cortex activity in Graves' disease: a functional near-infrared spectroscopy study

Introduction

Graves' disease (GD) is associated with cognitive, emotional, and fatigue difficulties. Objective measures of cognitive dysfunction have yielded mixed results. The aim of this study was to investigated whether premenopausal female patients with first-time hyperthyroid GD (mean age 34 years) exhibit cognitive fatigability and altered functional activity in the prefrontal cortex (PFC) using functional near-infrared spectroscopy (fNIRS) during an exhausting cognitive task.

Methods

Using the Animal Stroop test, we compared patients with GD (N = 28) and healthy controls (N = 28) before and after a 30-min cognitively exhausting reading comprehension task.

Results

Both groups showed improvements in Stroop task performance after the reading task (p < 0.001, η p 2 = 0.389), and no group differences were observed in cognitive performance. Increased activation in the left dorsolateral prefrontal cortex post-test was found for controls but not for patients with GD. Exploratory analyses showed higher increases in oxy-hemoglobin levels post-test in the PFC of controls compared to patients with GD, indicating reduced PFC involvement in patients with GD.

Discussion

In conclusion, we were not able to show any change in the functional activity of the PFC after prolonged mental activity in this set-up using fNIRS of hyperthyroid GD patients. Further studies are needed to understand the mechanism behind self-reported fatigue in GD.

Trauma-Based Sexually Dimorphic Changes in the Connectome and Its Association with Central Sensitization Syndromes-A Systematic Review

BACKGROUND/OBJECTIVES

Chronic pain syndromes pose a significant global health challenge to patients and physicians with a complex relationship of biological and psychosocial factors that are only partly understood. Emerging research suggests an association between prenatal and childhood adversity and the development of somatic syndromes, particularly in females. This study aims to explore the relationship between sexual dimorphic epigenetic changes in the connectome and prenatal and early life adversity (ELA).

METHODS

A review of the existing literature was conducted, examining studies utilizing MRI to identify critical periods of environmental influence on neural phenotypes.

RESULTS

The findings indicate a significant association between prenatal and childhood adversity and the emergence of central sensitization syndromes, particularly among females. Notably, alterations in grey matter volume and neural connectivity patterns were observed, suggesting that early adverse experiences can influence pain signaling mechanisms.

CONCLUSIONS

Understanding the role of sex differences in brain circuitry is crucial for developing personalized pain management strategies. This study highlights the importance of considering both biological and psychosocial factors in addressing chronic pain, as interventions based predominantly on male subjects may be less effective for females. Further research is warranted to explore these differences and refine therapeutic approaches.

Are resting metabolic rate and clinical symptoms affected by variation of serum thyroid stimulating hormone levels within the normal range in healthy and women with hypothyroidism? A case-control study

BACKGROUND

It is unclear whether variation in thyroid stimulating hormone (TSH) levels within the reference range affect energy expenditure and clinical symptoms and even within the normal range of TSH levels, resting energy expenditure may alter. The aim of the present study was to determine whether treated hypothyroid subjects and healthy subjects with a low-normal TSH range (0.3-2.3 mIU/L) have better clinical outcomes and increased energy expenditure than those with a high-normal TSH range (2.3-4.3 mIU/L).

METHODS

This was a case-control study of 160 overweight/obese women with TSH levels across the reference range of 0.3-4.3 mU/l. Subjects were paired in four groups: healthy subjects with low-normal target TSH (n = 40), healthy subjects with high-normal target TSH (n = 40), subjects with treated hypothyroidism with low-normal target TSH (n = 40), and subjects with treated hypothyroidism with high-normal target TSH (n = 40). Resting energy expenditure (RMR), dietary intake, body composition, physical activity, and biochemical markers were assessed.

RESULTS

Subjects with low-normal (≤2.3 mU/L) and high-normal (>2.3 mU/L) TSH levels did not differ in terms of RMR, serum T3 levels, and clinical symptoms except fatigue (P = 0.013). However, serum fT4 levels were found to be significantly different between the study groups (P = 0.002). Serum fT4 concentration was the highest in subjects with treated hypothyroidism with low-normal target TSH.

CONCLUSION

Variation in serum TSH levels within the reference range did not significantly affect REE and clinical symptoms except fatigue in healthy and women with hypothyroidism.

Unraveling the Complex Web of Fibromyalgia: A Narrative Review

Fibromyalgia is a complex and often misunderstood chronic pain disorder. It is characterized by widespread musculoskeletal pain, fatigue, and heightened sensitivity, and has evolved in diagnostic criteria and understanding over the years. Initially met with skepticism, fibromyalgia is now recognized as a global health concern affecting millions of people, with a prevalence transcending demographic boundaries. The clinical features and diagnosis of fibromyalgia encompass a range of symptoms beyond pain, including sleep disturbances and cognitive difficulties. This study emphasizes the importance of a comprehensive evaluation for accurate diagnosis, considering the shift from tender point reliance to a more holistic approach. Etiology and pathophysiology involve genetic predisposition, neurotransmitter dysregulation, central sensitization, and immune system involvement. Risk factors such as gender, age, family history, and comorbid conditions contribute to susceptibility. The impact on quality of life is profound, affecting physical and social aspects, often accompanied by mood disorders. Management approaches include pharmacological interventions, non-pharmacological therapies, lifestyle modifications, and alternative treatments. This study also delves into emerging research, exploring advances in neurobiological understanding, brain imaging, genetic markers, glutamate modulation, cannabinoids, gut microbiome, and digital health tools for fibromyalgia management. Overall, this study provides a nuanced and up-to-date overview of the complexities surrounding fibromyalgia, aiming to enhance understanding and support for individuals grappling with this challenging condition.

Autoantibodies to selenoprotein P in chronic fatigue syndrome suggest selenium transport impairment and acquired resistance to thyroid hormone

Chronic Fatigue Syndrome (CFS) presents with symptoms of hypothyroidism, including mental and physical fatigue, poor sleep, depression, and anxiety. However, thyroid hormone (TH) profiles of elevated thyrotropin and low thyroxine (T4) are not consistently observed. Recently, autoantibodies to the Se transporter SELENOP (SELENOP-aAb) have been identified in Hashimoto's thyroiditis and shown to impair selenoprotein expression. We hypothesized that SELENOP-aAb are prevalent in CFS, and associate with reduced selenoprotein expression and impaired TH deiodination. Se status and SELENOP-aAb prevalence was compared by combining European CFS patients (n = 167) and healthy controls (n = 545) from different sources. The biomarkers total Se, glutathione peroxidase (GPx3) and SELENOP showed linear correlations across the samples without reaching saturation, indicative of Se deficiency. SELENOP-aAb prevalence was 9.6-15.6% in CFS versus 0.9-2.0% in controls, depending on cut-off for positivity. The linear correlation between Se and GPx3 activity was absent in SELENOP-aAb positive patients, suggesting impaired Se supply of kidney. A subgroup of paired control (n = 119) and CSF (n = 111) patients had been characterized for TH and biochemical parameters before. Within this subgroup, SELENOP-aAb positive patients displayed particularly low deiodinase activity (SPINA-GD index), free T3 levels, total T3 to total T4 (TT3/TT4) and free T3 to free T4 (FT3/FT4) ratios. In 24 h urine, iodine concentrations were significantly lower in SELENOP-aAb positive than in SELENOP-aAb negative patients or controls (median (IQR); 43.2 (16.0) vs. 58.9 (45.2) vs. 89.0 (54.9) μg/L). The data indicate that SELENOP-aAb associate with low deiodination rate and reduced activation of TH to active T3. We conclude that a subset of CFS patients express SELENOP-aAb that disturb Se transport and reduce selenoprotein expression in target tissues. Hereby, TH activation decreases as an acquired condition not reflected by thyrotropin and T4 in blood. This hypothesis opens new diagnostic and therapeutic options for SELENOP-aAb positive CFS, but requires clinical evidence from intervention trials.

Hypothalamus and Post-Traumatic Stress Disorder: A Review

Humans have lived in a dynamic environment fraught with potential dangers for thousands of years. While fear and stress were crucial for the survival of our ancestors, today, they are mostly considered harmful factors, threatening both our physical and mental health. Trauma is a highly stressful, often life-threatening event or a series of events, such as sexual assault, war, natural disasters, burns, and car accidents. Trauma can cause pathological metaplasticity, leading to long-lasting behavioral changes and impairing an individual's ability to cope with future challenges. If an individual is vulnerable, a tremendously traumatic event may result in post-traumatic stress disorder (PTSD). The hypothalamus is critical in initiating hormonal responses to stressful stimuli via the hypothalamic-pituitary-adrenal (HPA) axis. Linked to the prefrontal cortex and limbic structures, especially the amygdala and hippocampus, the hypothalamus acts as a central hub, integrating physiological aspects of the stress response. Consequently, the hypothalamic functions have been attributed to the pathophysiology of PTSD. However, apart from the well-known role of the HPA axis, the hypothalamus may also play different roles in the development of PTSD through other pathways, including the hypothalamic-pituitary-thyroid (HPT) and hypothalamic-pituitary-gonadal (HPG) axes, as well as by secreting growth hormone, prolactin, dopamine, and oxytocin. This review aims to summarize the current evidence regarding the neuroendocrine functions of the hypothalamus, which are correlated with the development of PTSD. A better understanding of the role of the hypothalamus in PTSD could help develop better treatments for this debilitating condition.

Association of Vitamin B12, Vitamin D, and Thyroid-Stimulating Hormone With Fatigue and Neurologic Symptoms in Patients With Fibromyalgia

Objective

To assess the association between vitamin B12 (B12) deficiency and the prevalence of fatigue and prespecified neurologic symptoms in patients with fibromyalgia.

Patients and Methods

A retrospective chart analysis of patients diagnosed with fibromyalgia in the years 2015-2020 was performed. The values of B12 were collected. The chart reviews assessed reported fatigue and neurologic symptoms, including brain fog, memory loss, cognitive impairment, paresthesias, numbness, and tingling, to assess their correlation with B12 levels. Concurrent vitamin D and thyroid-stimulating hormone levels were reviewed to assess their association with fibromyalgia.

Results

A total of 2142 patients with fibromyalgia with documented levels of B12 and vitamin D were included. Of them, 42.4% had B12 deficiency (<400 ng/L). Fatigue and memory loss were more common in the B12 deficiency group. After adjusting for vitamin D levels, B12 deficiency remained statistically significantly associated with the presence of fatigue (odds ratio, 1.39; 95% confidence interval, 1.11-1.75; P=.004).

Conclusion

This is the first study to report the association of B12 in patients with fibromyalgia complaining of fatigue. This symptom was prevalent in our group of patients with fibromyalgia with B12 deficiency, regardless of whether the cutoff point was 400 or 350 ng/L.

Prevalence of Lactose Intolerance in Patients with Hashimoto Thyroiditis and Impact on LT4 Replacement Dose

Purpose: to determine lactose intolerance (LI) prevalence in women with Hashimoto’s thyroiditis (HT) and assess the impact of LI on LT4 replacement dose. Methods. consecutive patients with HT underwent Lactose Breath Test and clinical/laboratory data collection. Unrelated gastrointestinal disorders were carefully ruled out. Lactose-free diet and shift to lactose-free LT4 were proposed to patients with LI. Results: we enrolled 58 females (age range, 23−72 years) with diagnosis of HT. In total, 15 patients were euthyroid without treatment, and 43 (74%) euthyroid under LT4 (30 of them with a LT4 formulation containing lactose). Gastrointestinal symptoms were present in 84.5% of patients, with a greater prevalence in change in bowel habits in lactose-intolerant patients (p < 0.0001). The cumulative LT4 dose required did not differ in patients with or without LI. No significant difference in both TSH values and LT4 dose were observed in patients shifted to lactose-free LT4 and diet at 3 and 6 months compared to baseline. Conclusion: the prevalence of LI in patients with HT was 58.6%, not different from global prevalence of LI. In the absence of other gastrointestinal disorders, LI seems not to be a major cause of LT4 malabsorption and does not affect the LT4 required dose in HT patients.

Hair cortisol levels in women with medically unexplained symptoms

Stress has been demonstrated to be involved in the development of medically unexplained symptoms. A key underlying mechanism could be lower levels of cortisol, which can contribute to symptoms such as fatigue or pain. However, the literature is highly equivocal, which may be due to methodological limitations inherent in short-term cortisol assessment. The aim of this case-control study was to investigate, for the first time, whether individuals with different forms of medically unexplained symptoms show altered hair cortisol concentrations, a long-term marker of hypothalamic-pituitary-adrenal functioning. Two groups of women with medically unexplained symptoms were recruited. The first had a functional somatic syndrome, characterised by specific medically unexplained symptoms (i.e., chronic fatigue syndrome, fibromyalgia, or irritable bowel syndrome, n = 33). The second had somatic symptom disorder, characterised by excessive thoughts, feelings, and behaviours devoted to various medically unexplained symptoms (n = 23). These groups were contrasted with healthy controls (n = 30), and women with depression (n = 27). Cortisol representing the previous three months was extracted from hair. Chronic stress and childhood trauma were assessed (retrospectively). Women with somatic symptom disorder had lower hair cortisol than healthy controls and women with functional somatic syndromes. No differences in hair cortisol were found between healthy controls, functional somatic syndromes, and depression. Neither childhood trauma nor chronic stress was correlated with hair cortisol. Provided that our findings are replicated, they may suggest that hypocortisolism is found in a specific subgroup of individuals with medically unexplained symptoms, and potentially in those characterised by excessive thoughts, feelings, and behaviours about symptoms.

Life-course effects of early life adversity exposure on eating behavior and metabolism

Environmental variations in early life influence brain development, making individuals more vulnerable to psychiatric and metabolic disorders. Early life stress (ELS) has a strong impact on the development of eating behavior. However, eating is a complex behavior, determined by an interaction between signals of energy homeostasis, neuronal circuits involved in its regulation, and circuits related to rewarding properties of the food. Although mechanisms underlying ELS-induced altered feeding behavior are not completely understood, evidence suggest that the effects of ELS on metabolic, mood, and emotional disorders, as well as reward system dysfunctions can contribute directly or indirectly to altered feeding behavior. The focus of this chapter is to discuss the effects of ELS on eating behavior and metabolism, considering different factors that control appetite such as energy homeostasis, hedonic properties of the food, emotional and cognitive status. After highlighting classic studies on the association between ELS and eating behavior alterations, we discuss how exposure to adversity can interact with genetics characteristics to predict variable outcomes.

Altered Experienced Thermoregulation in Depression-No Evidence for an Effect of Early Life Stress

Objectives: Accumulating evidence suggests that individuals with depression are characterised by difficulties in thermoregulatory cooling. The aim of this study was to investigate, for the first time, whether depressed individuals are aware of these alterations, what their physical consequences are and whether they may be rooted in early life stress. Methods: A total of N = 672 medically healthy individuals from the general population were recruited to participate in an online survey. Participants were divided into depressed vs. non-depressed using the Patient Health Questionnaire. Experienced autonomic and behavioural thermoregulation as well as vigilance problems in response to temperature increases were assessed by the Experienced Temperature Sensitivity and Regulation Survey. The Childhood Trauma Questionnaire was administered to assess early life stress. Results: Controlling for age, sex, body mass index, and physical activity, depressed vs. non-depressed individuals did not differ in their experienced autonomic and behavioural responses to temperature increases. However, the depressed individuals reported comparably greater difficulties in concentrating and drowsiness/fatigue in warm environments (p = 0.029), during physical exertion (p = 0.029), and during stress (p < 0.001). There were no differences in the experienced thermoregulation between depressed individuals with vs. without early life stress. Conclusions: Depressed individuals experienced more severe physical impairments (i.e., greater vigilance problems) in response to intense warmth when compared to non-depressed individuals. These differences were not attributable to comorbid illnesses, the intake of medication, or physical deconditioning. Further enquiries in clinical populations are warranted to investigate to what extent the observed alterations map onto specific symptoms of depression (e.g., sleep disturbances).

Sex Dimorphic Responses of the Hypothalamus-Pituitary-Thyroid Axis to Maternal Separation and Palatable Diet

Neonatal stress contributes to the development of obesity and has long-lasting effects on elements of the hypothalamus-pituitary-thyroid (HPT) axis. Given the importance of thyroid hormones in metabolic regulation, we studied the effects of maternal separation and a high-fat/high-carbohydrate diet (HFC), offered from puberty or adulthood, on HPT axis activity of adult male and female Wistar rats. Pups were non-handled (NH) or maternally separated (MS) 3 h/day at postnatal days (Pd) 2-21. In a first experiment, at Pd60, rats had access to chow or an HFC diet (cookies, peanuts, chow) for 1 month. Male and female NH and MS rats that consumed the HFC diet increased their caloric intake, body weight, and serum insulin levels; fat weight increased in all groups except in MS males, and serum leptin concentration increased only in females. Mediobasal hypothalamus (MBH) Pomc expression increased in NH-HFC females and Npy decreased in NH-HFC males. MS males showed insulinemia and hypercortisolemia that was attenuated by the HFC diet. The HPT axis activity response to an HFC diet was sex-specific; expression of MBH thyrotropin-releasing hormone-degrading ectoenzyme (Trhde) increased in NH and MS males; serum TSH concentration decreased in NH males, and T4 increased in NH females. In a second experiment, rats were fed chow or an HFC diet from Pd30 or 60 until Pd160 and exposed to 1 h restraint before sacrifice. Regardless of neonatal stress, age of diet exposition, or sex, the HFC diet increased body and fat weight and serum leptin concentration; it induced insulinemia in males, but in females only in Pd30 rats. The HFC diet's capacity to curtail the hypothalamus-pituitary-adrenal axis response to restraint was impaired in MS males. In restrained rats, expression of Trh in the paraventricular nucleus of the hypothalamus, Dio2 and Trhde in MBH, and serum thyroid hormone concentration were altered differently depending on sex, age of diet exposition, and neonatal stress. In conclusion, metabolic alterations associated to an HFC-diet-induced obesity are affected by sex or time of exposition, while various parameters of the HPT axis activity are additionally altered by MS, pointing to the complex interplay that these developmental influences exert on HPT axis activity in adult rats.