Search Results (91)

Background: Patients in Intensive Care Units (ICUs) often develop non-thyroidal illness syndrome. Potentially, thyroid hormones may be removed during continuous veno-venous hemodiafiltration (CVVHDF), as their molecular size is smaller than the filter pores’ cutoff. The study’s main aim was to assess whether the serum concentration of thyroid hormones changes over time during CVVHDF. Methods: This was a prospective observational trial that included 30 patients treated in an ICU. All patients developed acute kidney injury (AKI) and had clinical indications for implementation of CVVHDF. Blood samples were collected before initiation of CVVHDF and at 1, 2, 3, 6, 9 and 12 days after. The last sample was collected three days after CVVHDF withdrawal. Thyroid function was evaluated by determining the serum concentration of TSH, thyrotropin-releasing hormone (TRH), free triiodothyronine (fT₃), free thyroxine (fT₄), total triiodothyronine (tT₃), total thyroxine (tT₄) and reverse triiodothyronine (rT₃). We additionally calculated the total activity of peripheral deiodinases (G_D) using a mathematical model. Results: TRH and TSH levels remained mostly within normal ranges. fT4 and tT4 were in normal range or slightly below. In contrast, fT3 and tT3 were undetectably low in most patients throughout. Reverse T3 levels remained within normal limits. There were no statistically significant changes in any thyroid hormone levels over the CVVHDF treatment period. The calculated peripheral G_D activity was lower than normal, but importantly, it did not change significantly over time. Conclusions: Thyroid hormones are not lost due to hemodiafiltration. Decreased deiodinases activity is responsible for alterations in serum concentrations of thyroid hormones in patients during CVVHDF. Full article

Background/Objectives: Frailty is a key determinant of outcomes in older adults with heart failure (HF). The free triiodothyronine/free thyroxine (FT₃/FT₄) ratio has emerged as a promising frailty biomarker that reflects metabolic and systemic resilience. This study investigates its association with frailty, nutrition, muscle strength, inflammation, and one-year mortality in very old patients with HF. Methods: In this longitudinal, single-center study, we enrolled 193 older outpatients (mean age, 86.5 ± 6.1 years; 56% women) recently discharged after acute HF. All patients underwent physical examination, blood testing, and comprehensive geriatric assessment, including handgrip strength (HGS). Participants were stratified by FT₃/FT₄ ratio (<1.7 vs. ≥1.7). Associations with the Clinical Frailty Scale (CFS) were examined using multivariable linear regression. Spearman’s correlations assessed relationships with inflammatory and nutritional biomarkers. Cox regression evaluated the association with all-cause mortality. Results: Patients with a low FT₃/FT₄ ratio (31.1%) exhibited greater frailty (CFS: median [IQR], 6 [2] vs. 4 [3]; p = 0.020), poorer nutritional status (Mini Nutritional Assessment: 10 [4] vs. 12 [3]; p = 0.008), and lower HGS (mean ± SD, 16.8 ± 3.7 kg vs. 20.3 ± 4.8 kg; p = 0.002). An inverse association was identified between the FT₃/FT₄ ratio and frailty (adjusted β = −0.09; p = 0.019). Individuals with low FT₃/FT₄ also showed elevated inflammatory markers and had more than double the one-year mortality rate compared to those with higher ratios [HR 2.32 (95% CI, 1.24–4.34; p = 0.007)]. Conclusions: In very old adults recently hospitalized for HF, a lower FT₃/FT₄ ratio was associated with frailty, malnutrition, inflammation, and increased mortality, supporting its potential role as a marker of biological vulnerability. Full article

Objective: This study evaluated the systemic bioavailability of L-thyroxine (L-T4) in healthy women following repeated cutaneous application of a new gel formulation containing L-T4 and escin. Plasma concentrations of free triiodothyronine (FT3), reverse triiodothyronine (rT3), and thyroid-stimulating hormone (TSH) were also assessed, along with local and systemic tolerability. Methods: Thirty healthy women participated in a single-group, open-label trial. L-thyroxine gel was applied at 20 g/day for the first 2 days and 10 g/day for the following 26 days (equivalent to 20 mg/day and 10 mg/day of L-T4, respectively). Blood samples were collected at Baseline, 5 and 24 h after the first application, and on Days 14, 28 (End of Treatment, EOT), and 42 (End of Study, EOS). Tolerability and safety were monitored throughout. Results: Plasma FT4 concentrations remained stable throughout the study, with no clinically significant changes from Baseline (1.13 ± 0.15 ng/dL) to EOT (1.11 ± 0.13 ng/dL). FT3 and TSH levels also remained within physiological ranges, with only a transient, non-clinically relevant decrease observed 5 h after the first application. No changes in rT3 concentrations were detected at any time point. No serious adverse events were reported. Conclusions: This study confirms that repeated application of L-thyroxine/escin gel over 28 days (total exposure of 300 g) does not affect systemic thyroid hormone levels and is well tolerated in healthy women. These findings support the hypothesis that intact skin acts as an effective barrier to transdermal L-T4 absorption. Full article

Background/Objectives: This study aimed to investigate the effects of thyroxine replacement therapy (TRT) on serum Maresin 1 and nuclear factor kappa beta (NF-kB) levels in patients with Hashimoto’s thyroiditis (HT). Methods: A total of 90 patients were included in this study, 60 with HT and 30 without. Patients in the HT group were divided into two groups according to whether they received TRT. Group 1 included 30 patients who underwent TRT, and Group 2 comprised 30 patients who were newly diagnosed with HT, either euthyroid or hypothyroid. The analysis included serum levels of thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), thyroid peroxidase antibody (TPOAb), Maresin 1, and NF-kB. Results: The serum NF-kB level in the TRT group was significantly higher than that in the control and non-TRT groups. In the subgroup analysis of patients who did not receive TRT, the serum NF-kB level in euthyroid patients was significantly lower than that in hypothyroid patients. Maresin 1 levels in the control group were significantly higher than those in patients who did and did not receive TRT. The serum Maresin 1 level in the TRT group was significantly lower than that in the untreated group. Maresin 1 levels were higher in the euthyroid group than in the hypothyroid group. TPOAb levels were positively correlated with NF-kB and negatively correlated with Maresin 1. Conclusions: TRT maintains the euthyroid state in patients with HT, but may not contribute positively to the pro-anti-inflammatory balance in these patients. Full article

Background/Objectives: Hashimoto’s thyroiditis (HT) is an autoimmune disease influenced by genetic factors and environmental triggers that affect immune system function. Data suggest that vitamin D may also play a role in the etiopathogenesis of HT. Methods: This retrospective study included patients admitted to the Endocrinology and Metabolic Diseases Outpatient Clinic. Data from individuals aged 18 years and older were analyzed, including serum levels of thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4), anti-thyroid peroxidase (anti-TPO), anti-thyroglobulin (anti-TG), and vitamin D. HT was diagnosed based on the presence of anti-TPO and/or anti-TG antibodies, while individuals with negative results for both were classified as non-HT. Thyroid function was categorized as euthyroid if TSH levels were between 0.55 mU/L and 4.78 mU/L and fT4 levels were between 0.89 ng/dL and 1.76 ng/dL; hypothyroid status was defined as TSH > 4.78 mU/L. Vitamin D levels were classified as deficient (<50 nmol/L), insufficient (50–74.9 nmol/L), or sufficient (≥75 nmol/L). Results: Of the total participants, 25,018 did not have HT, while 27,800 were diagnosed with HT. Vitamin D level was significantly higher in the HT group than the non-HT group (41.43 nmol/L and 39.44 nmol/L, p < 0.001). Vitamin D deficiency was present in 65.5% of the non-HT group and 62.1% of the HT group (p < 0.001). Subgroup analyses based on thyroid function showed that vitamin D levels were highest in the euthyroid HT group and similar in the euthyroid non-HT, hypothyroid non-HT, and hypothyroid HT groups (p < 0.001). Conclusions: In conclusion, while vitamin D levels were higher in the HT group compared to the non-HT group, no clinically significant association between vitamin D levels and HT or autoantibody positivity was observed. Vitamin D deficiency was more prevalent in the hypothyroid group compared to the euthyroid group. This study suggests that although vitamin D deficiency may not be directly involved in the pathogenesis of HT, it may still play a role in modulating immune activity or influencing the disease phenotype.. Full article

Objective: This study aims to evaluate the application effect of endoscopic thyroidectomy via the gasless unilateral axillary (GUA) approach in thyroid cancer and its impact on the postoperative stress response. Methods: Ninety-four thyroid cancer patients were enrolleod and assigned into the open group (underwent conventional-open-anterior-cervical-approach thyroidectomy) and the endoscopic group (underwent GUA endoscopic thyroidectomy) (n = 47). Perioperative indicators between the two groups were compared. Thyroid function parameters [total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH)] were measured preoperatively and on postoperative day 2. Inflammatory markers [interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α)] and stress-related hormones [norepinephrine (NE) and cortisol (Cor)] were evaluated preoperatively and on postoperative day 1. The aesthetic appearance of the incision was evaluated at 1 and 3 months postoperatively using the Vancouver Scar Scale (VSS). Postoperative complications were also compared between the two groups. Results: The endoscopic group exhibited less intraoperative blood loss, reduced postoperative drainage, a lower pain degree on 1 day postoperatively, a shorter hospitalization time, and a longer surgical time versus the open group (p < 0.05). The serum levels of TT3, TT4, FT3, and FT4 were lower, while the TSH levels were higher in both groups on postoperative day 2 compared to preoperative values. Additionally, the serum levels of IL-6, TNF-α, NE, and Cor increased on day 1 postoperatively, with the endoscopic group showing lower levels of these markers compared to the open group (p < 0.05). The VSS scores at 1 and 3 months after surgery were lower in the endoscopic group compared to the open group, indicating better cosmetic outcomes (p < 0.05). The incidence of postoperative complications was comparable between the endoscopic and open groups (p > 0.05). Conclusions: Endoscopic thyroidectomy by a GUA offers notable advantages over the conventional-open-anterior-cervical-approach thyroidectomy, including reduced intraoperative blood loss, less postoperative drainage, and a lower postoperative stress response. This approach also results in improved cosmetic outcomes, making it a promising alternative for thyroid cancer surgery. Full article

Six isoforms of uncoupling proteins (UCPs) exist, spanning from UCP1 to UCP6. A precise physiological function has only been established for UCP1, which is involved in non-shivering thermogenesis, but the functions of other UCPs are still not fully defined. Therefore, the purpose of the present study is to search for indications of the involvement of nine polymorphic variants of UCP1-6 genes in human adaptation to cold climates using four criteria: (1) the presence of associations of polymorphic variants of UCP genes with levels of thyroid-stimulating hormone, free triiodothyronine, and free thyroxine; (2) the presence of associations of polymorphic variants of UCP genes with changes in thyroid homeostasis (SPINA); (3) the presence of associations of polymorphic variants of UCP genes with body surface area; (4) the presence of signals of directional selection to cold climate for polymorphic variants of UCP genes. As a result of the evaluation, the highest scores for cold adaptation traits were recorded for polymorphic variants rs3811787 of the UCP1 gene and rs1800849 of the UCP3 gene. We suggest that the results obtained indicate the importance of uncoupling proteins UCP1 and UCP3 in human adaptation to cold through processes of non-shivering and shivering thermogenesis. Full article

Turner syndrome (TS) is a genetic disorder caused by abnormalities in one of the X chromosomes. Individuals with TS have a higher incidence of autoimmune thyroid disorders, particularly Hashimoto’s disease, leading to thyroid dysfunction, most commonly hypothyroidism. Hormonal imbalance, growth hormone deficiency, and reduced physical activity contribute to muscle weakness in TS patients, and thyroid dysfunction can exacerbate these effects. The purpose of this study was to evaluate whether thyroid factors affect muscle strength in female patients with TS. The study included 70 women with TS and 88 age- and weight-matched controls. TS diagnoses were genetically confirmed (mosaic karyotypes: n = 20; monosomy X: n = 37; structural abnormalities: n = 7). The main criterion for exclusion from the study was unbalanced thyroid function. Serum levels of thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), and thyroid antibodies (anti-thyroid peroxidase antibodies (aTPO), anti-thyroglobulin antibodies (aTG)) were measured, and muscle strength was assessed using hand-held dynamometry. In TS patients, higher TSH levels were positively correlated, and higher fT4 levels were negatively correlated with muscle strength. No such correlations were found in controls. Thyroid compensation may impact musculoskeletal health in TS. Lower-normal TSH levels are associated with reduced muscle strength, and autoimmune thyroid changes like aTPO and aTG may contribute to muscle deterioration. Further research is needed to confirm these findings. Full article

The Cluster of Differentiation 5-like protein (CD5L) is produced by tissue-resident macrophages. It is an innate immune mediator protein with a multitude of functions, such as binding of invading microorganisms and oxidised LDL, and it is associated with clinical conditions, i.e., atherosclerosis and inflammation. The circulating CD5L level has been reported to correlate to selenium status and thyroid hormone activity. In order to test this hypothesis, we analysed CD5L in serum samples from a randomized controlled trial (RCT) with selenium and coenzyme Q₁₀ supplementation and examined associations between CD5L and thyroid hormones, health-related quality-of-life (Hr-QoL), and mortality in an elderly population low in selenium. Circulating levels of CD5L and thyroid hormones were determined in 359 elderly community-living individuals enrolled in an RCT at inclusion and after 48 months of supplementation (179 received selenium and coenzyme Q₁₀, and 180 placebo). Hr-QoL was recorded at both time-points using Short Form 36. Pre-intervention plasma selenium was low, mean 67 µg/L. CD5L correlated positively to free tri-iodothyronine (fT3) and showed an inverse relation with thyroid stimulating hormone (TSH). Low CD5L concentrations at inclusion in the placebo group were associated with increased cardiovascular mortality during 10 years of follow-up, and impaired Hr-QoL at 48 months. Selenium and coenzyme Q₁₀ supplementation significantly increased CD5L and fT3 levels, in association with a better health outcome. The data indicate that circulating CD5L positively responds to selenium and coenzyme Q₁₀ supplementation, correlates with thyroid hormone status, and associates with positive health indices. The observed effect may be due to increased selenium-dependent deiodinase isozyme expression that converts thyroxine (T4) to T3 locally and supports thyroid hormone activities. Whether the observed associations with Hr-QoL and cardiovascular mortality are a direct effect of circulating CD5L or local thyroid hormone activity is unclear and should be further investigated. Full article

Studies have shown that per- and polyfluoroalkyl substances (PFAS) may impact thyroid function in human health. While the consistency between PFAS exposure and thyroid health effects in pregnant women has been validated, the effects on men and non-pregnant women remains inconclusive. To address this, a meta-analysis was carried out in this paper, with 14 eligible studies retrieved from Embase, PubMed, and Web of Science that were published up to 2 June 2024, focusing on the relationship between PFAS exposure and its effect on thyroid hormone levels in the human body. The thyroid function indexes analyzed included thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), free T3 (FT3), and free T4 (FT4). The estimated value (β) and the corresponding confidence interval (95% CI) were extracted from the literature. A heterogeneity test was carried out, and the sensitivity analysis and publication bias of the studies were analyzed using Stata 18.0. The results revealed that in men and non-pregnant women, PFOA was positively correlated with FT3 (β = 0.011, 95% CI = 0.001, 0.02, I² = 13.4). However, no significant associations were found between exposure to other PFAS and thyroid hormones. A subgroup analysis further indicated that the correlations between PFAS exposure and thyroid hormone levels were more significant in adolescents, in both America and Europe. Full article

Graves’ disease (GD) is an autoimmune disorder that can be difficult to distinguish from other diseases due to symptom similarity. The exacerbation of GD owing to delayed diagnosis is a serious issue, and a novel accessible health screening system is needed. Therefore, this study investigated the association between GD and thyroid hormone levels in women’s hair and evaluated the prediction accuracy of this non-invasive type of sample. By optimizing pretreatment and analysis techniques using liquid chromatography–mass spectrometry (LC-MS), free triiodothyronine (FT3) and thyroxine (FT4) could be detected in only 2 mg of hair with high sensitivity. Compared with healthy controls, the thyroid hormone levels in the hair of GD patients were significantly higher in correlation with blood levels. The predictive ability of hair thyroid hormones was analyzed using a receiver operating characteristic (ROC) curve, and the optimal cut-off value was determined via the Youden index. As a result, the area under the curve (AUC) was 0.974 (95% confidence interval (CI): 0.935–1.000) for FT3 and 0.900 (95% CI: 0.807–0.993) for FT4. The cut-off value was 0.133 pg/mg (sensitivity: 91.2%; specificity: 100%; positive predictive value (PPV): 100%; negative predictive value (NPV): 76.9%) for FT3 and 0.067 pg/mg (sensitivity: 70.6%; specificity: 100%; PPV: 100%; NPV: 50.0%) for FT4. Collectively, our new approach offers the possibility of accurately and non-invasively detecting GD using hair samples. Since hair can be stored and transported at room temperature, this system facilitates large-scale screening at locations including hair salons and homes, potentially enabling the early determination of GD outside of medical facilities. Full article

Background: Arterial thrombosis (AT), the main clinical manifestations of which are ischemic heart disease (IHD) and ischemic stroke (IS), is associated with lowered free triiodothyronine (fT3) in acute ischemic stroke (aIS) and acute myocardial infarction (aMI) but increased reverse T3 (rT3) in aMI, which are associated with worse outcomes at one year. Whether such associations remain independent over a longer follow-up period and the value of rT3 in aIS outcomes are largely unknown. This study was dedicated to examining the impact of fT3 and rT3 on aIS and aMI all-cause mortality over a longer 5-year period. Methods: Individuals from Lithuania who experienced aIS and aIM were included in this study. Serum fT3, rT3, free thyroxin and thyroid-stimulating hormone values were examined on admission to the intensive care department. Follow-up for all-cause mortality was divided into two time periods: 1 and 5 years. Results: The final study (aIS cohort age, 67.5 ± 9.6 years, 41.5% women and aMI cohort age, 61.8 ± 11.4 years, 28% women) consisted of 241 aIS and 289 aMI individuals, respectively. Lower fT3 was independently associated (OR = 0.41; 95% CI: 0.17–0.99, p = 0.049) with aIS, and higher rT3 (OR = 1.69; 95% CI: 1.06–2.67, p = 0.027) with aMI with increased all-cause mortality at 1 year. No associations were found between studied hormones and all-cause mortality at 5 years in both conditions. Conclusions: Lower fT3 in aIS and higher rT3 in aMI are associated with higher all-cause mortality at 1 year. No such associations were found at 5 years. Full article

Vasoactive molecules are central regulators of vascular tone, angiogenesis and inflammation. Key molecular agents include nitric oxide (NO), endothelin-1 (ET-1), prostacyclin, free triiodothyronine (fT3), leptin, low-density lipoprotein (LDL), high-density lipoprotein (HDL), superoxide dismutase (SOD), and glutathione peroxidase (GPX). Dysregulation of these compounds can lead to endothelial dysfunction, an early predictor of atherosclerosis and cardiovascular diseases (CVD). Maintaining endothelial health is thus essential for vascular homeostasis and cardiovascular risk prevention. Regular exercise serves as a vital protective measure against CVD and the risk of cardiovascular conditions. However, young athletes often significantly exceed recommended levels of training load, engaging in highly intensive training that leads to substantial physiological adaptations. Despite this, research on the impact of exercise on vasoactive substances in children and adolescents, particularly young athletes, is limited and inconsistent. Most studies focus on those with pre-existing conditions, like obesity or diabetes mellitus. Existing findings suggest exercise may favorably affect vascular biomarkers in youth, but methodological variations hinder consistent conclusions. This literature review examines 68 studies on the effects of exercise on vascular molecules in children and adolescents, young athletes, and children and adolescents with pre-existing conditions, offering deeper insights into how exercise may influence vascular health at the molecular level. Full article

Background/Objectives: Thyroid hormones (THs) are correlated with body composition regardless of the presence of thyroid dysfunctions, whereas little is known regarding THs’ influence on muscular fitness components. This cross-sectional study investigated whether THs may affect muscular parameters in adults who are overweight and affected obesity. Methods: One hundred and five volunteers (65 females and 40 males, BMI: 33.5 (8.0) kg/m²) in an euthyroid state were enrolled. Body composition was evaluated using bioelectrical impedance analysis. Muscular parameters of interest were grip strength—evaluated using the handgrip test (HG) and muscular performance –evaluated using the 10-repetition chair-stand test (CST). Free-triiodothyronine (FT3), free-thyroxine (FT4) and their ratio (FT3/FT4) were evaluated to assess thyroid function. Results: In the female group, the Pearson linear regression analysis revealed a positive correlation between FT3 and HG (R = 0.261, p = 0.036) and a negative correlation between FT3/FT4 and CST (R= −0.266, p= 0.032). In the male group, a positive correlation between FT3 and skeletal muscle mass was found (R = 0.354, p = 0.025). No correlations were found between THs of interest and adiposity indexes (BMI, fat mass) in either group (p > 0.05). Conclusion: FT3 and FT3/FT4 ratio levels in euthyroidism may influence muscular parameters differently in females and males affected by an excess of fat mass. More research is needed to understand the mechanisms behind this correlation and whether THs could be a potential biomarker for muscle-related parameters. Full article

Artificial rearing (AR) of lambs is nowadays a common practice in Mediterranean dairy sheep production systems to enhance the milk available for cheese or yoghurt manufacturing. The sufficient growth of lambs in an AR system is vital for the economic success of dairy sheep farms. However, AR is often associated with negative impacts on the performance and physiology of lambs. Greece is one of the major producers of ovine milk; nevertheless, data concerning the effects of artificial rearing in lambs of Greek autochthonous breeds are not available. Therefore, the present study aimed to examine the influence of artificial rearing on growth performance, thyroid hormone levels, locomotor activity, carcass traits and meat quality characteristics in lambs of the Chios breed, which is one of the most well-known Greek dairy sheep breeds. Twenty-one singleton male lambs were assigned into two feeding regimes; natural rearing NR (n = 11) and AR (n = 10). The lambs’ behavior was continuously videotaped until weaning, and their standing percentage was recorded as an activity index. Blood samples were collected from the jugular vein of lambs on days 3, 10, 17 and 40 after birth to assess thyroid hormone levels. The body weight of lambs was also recorded weekly. At the age of 45 days, lambs were fasted for 12 h, weighed and slaughtered. The weights of the carcass and internal organs were measured, while samples of the longissimus dorsi muscle were used for the determination of meat pH, color, water holding capacity, shear force and oxidative stability values. As indicated, body weight (kg) at birth was greater in NR vs. AR group and this difference was maintained till day 35 (p < 0.05), although body gain (kg) was generally not significantly different between NR and AR lambs, with the exception of the first week, when NR showed a greater value compared with the AR lambs (p < 0.001). On day 42, no significant differences between lamb groups for body weight were observed. Levels for triiodothyronine (T3), thyroxine (T4) and the free form of T3 (FT3) were greater, whereas the standing percentage was lower in NR compared with AR lambs (p < 0.05). The feeding regime of lambs did not affect carcass traits, internal organ and fat tissue weights, except for cold carcass yield which was greater in AR vs. NR lambs. No significant differences were observed between the two lamb groups in meat quality characteristics, such as pH, color, water holding capacity and shear force values, although MDA content was decreased in AR lambs indicating an improved oxidative stability. In conclusion, artificial rearing appears to be a feasible strategy for Chios lamb meat production, since it does not negatively influence carcass traits and meat quality characteristics, while a positive effect in meat oxidative stability is observed. Full article