The protective role of nutritional antioxidants against oxidative stress in thyroid disorders

Advances in flavonoid bioactivity in chronic diseases and bioavailability: transporters and enzymes

Flavonoids, abundant in the human diet, have been extensively studied for their therapeutic bioactivities. Recent research has made significantly advances in our understanding of the biological activities of flavonoids, demonstrating their therapeutic effects for various chronic diseases. However, the generally low bioavailability of flavonoids limits their effectiveness. Therefore, it is essential to explore the pharmacokinetics of flavonoids, paying particular attention to the roles of transporters and metabolizing enzymes. This paper reviews recent studies on the bioactivity of flavonoids, highlighting the importance of transporters and metabolic enzymes in their pharmacokinetics.

A Comprehensive Review of Selenium as a Key Regulator in Thyroid Health

Selenium (Se) is an essential trace element crucial for thyroid function, participating in the production and metabolism of thyroid hormones and the immune system. It engages in synthesizing selenoproteins, which are essential for antioxidant defense and regulating thyroid hormone levels. It is crucial to convert thyroxine (T4) into the active thyroid hormone triiodothyronine (T3) via deiodinase activity and safeguard thyroid cells from oxidative damage. Therefore, thyroid dysfunction, including abnormalities in thyroid hormone synthesis and the emergence of autoimmune thyroid conditions such as Graves' disease and Hashimoto's thyroiditis, has been linked to Se deficiency. When evaluating the benefits of Se supplementation, it is crucial to recognize that excessive mineral intake may be detrimental and result in adverse consequences, including gastrointestinal disturbances and neurological problems. The effectiveness of Se-based therapies is influenced by individual characteristics, including hereditary anomalies in thyroid function and Se metabolism. Further research should be performed on personalized Se supplementation approaches using genetics and nanotechnology to optimize the bioavailability and efficacy of the supplements. This study aims to thoroughly examine Se's role in thyroid health and how its therapeutic use in thyroid-related diseases may be optimized via appropriate dosing.

Aqueous Vernonia amygdalina leaf extract in drinking water mitigates aflatoxin B1 toxicity in broilers: effects on performance, biomarker analysis, and liver histology

This study evaluated aqueous Vernonia amygdalina leaf extract in drinking water as a mitigation strategy against Aflatoxin B1-induced toxicity in broilers, focusing on performance, haematology, serum biochemistry, pro-inflammatory cytokines, cellular stress markers, and liver histology. Two hundred and forty (240) day-old chicks (mixed sex), of the Cobb 500 breed were divided into four groups: control (CONT), AFB1-exposed (AFLB1), and two treatment groups (VE1AF and VE2AF) receiving 0.5 mg/kg AFB1 and Vernonia amygdalina aqueous extract at 1 g/L and 2 g/L, respectively. At 42 days, VE1AF and VE2AF chickens showed higher (P < 0.05) final weights and weight gains than CONT and AFLB1 groups. The red blood cells, packed cell volume, haemoglobin, and white blood cell counts were higher (P < 0.05) in CONT, VE1AF, and VE2AF groups compared to AFLB1. Mean cell volume, and mean cell haemaoglobin were higher (P < 0.05) in AFLB1 and VE2AF. Serum analysis revealed lower (P < 0.05) total protein, globulin, and albumin in AFLB1, which were restored by the extract. The tumor necrosis factor-α, interleukin-6, interleukin-1β, and interferon-γ, were elevated (P < 0.05) in AFLB1 but reduced in VE1AF and VE2AF. The heat shock protein 70, 8-hydroxy-2'-deoxyguanosine and adiponectin levels were higher (P < 0.05) in AFLB1, but were normalized by the extract in VE1AF and VE2AF. Leptin and triiodothyronine levels were significantly (P < 0.05) better in VE1AF and VE2AF, compared to AFLB1. Liver histology showed reduced inflammation in VE1AF and VE2AF, with near-normal hepatic architecture. In conclusion, Vernonia amygdalina leaf extract effectively counteracts AFB1 toxicity, enhancing overall health and performance in broiler chickens.

Impact of L-thyroxine on hippocampal activity, morphology, and behavioral performance in thyroidectomized rats

Thyroid hormones, particularly L-thyroxine, are integral to cognitive processes like learning and memory. However, electrophysiological and morphological evidence connecting thyroid hormone activity to hippocampal function remains limited. This study aims to investigate the electrophysiological, morphological, and behavioral effects of L-thyroxine treatment in thyroidectomized (TX) rats, addressing the complex interplay between thyroid hormone regulation and hippocampal function. Adult male and female Wistar rats were assigned to three groups: TX, TX + L-thyroxine (10 µg/100 g/day, i.p., administered one week post-surgery for 4 weeks), and vehicle-control. Behavioral assessments were conducted prior to electrophysiological and morphological recordings. Under urethane anesthesia, hippocampal electrical activity was recorded following entorhinal cortex stimulation, while morphological changes were assessed in the capillary networks of both the hippocampus and the paraventricular nucleus. Results revealed significant changes in hippocampal electrophysiological responses in the L-thyroxine-treated group, including enhanced synaptic plasticity, increased excitatory activity, and more frequent, synchronized neuronal firing in the CA1 and CA3 regions. Additionally, L-thyroxine treatment led to changes in capillary morphology. This integrative study bridges electrophysiological, morphological, and behavioral approaches, enhancing our understanding of thyroid hormone influence on hippocampal function. The findings suggest that the observed electrophysiological and morphological changes could contribute to the cognitive and memory-related symptoms reported by individuals with thyroid dysfunction.

[Open experiment: quantitative proteomics analysis of thyroid-cancer tissue slices using ultra-high performance liquid chromatography-tandem mass spectrometry]

Open experiments play crucial roles in developing undergraduate students' practical abilities, innovative thinking, and teamwork. This open experiment is designed to use ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) in proteomics, a frontier field, by quantitatively analyzing thyroid-cancer-tissue-slice samples. Various reagents are first screened for further study by evaluating their abilities to extract proteins. This approach aims to foster students' hands-on abilities and their scientific-research thinking. The liquid-chromatography method is subsequently optimized to enable deep-coverage of the proteome, thereby enhancing students' understanding of liquid chromatography and mass spectrometry. Paraffin-embedded thyroid-cancer-tissue slices are finally subjected to quantitative proteomic analysis, resulting in the identification of 33 differentially expressed proteins, thereby demonstrating their potential use in disease-typing applications. This open experiment integrates theoretical and experimental knowledge gained through instrumental analysis, analytical chemistry, and biochemistry, thereby imparting scientific research thinking and innovative spirit to undergraduates. It also provides students with opportunities to expand and solidify theoretical knowledge through hands-on instrumental operation and experiments, which helps to build a systematic knowledge framework and develop a comprehensive understanding of relevant fields. Moreover, it stimulates undergraduate interest in scientific research, cultivates innovative thinking, and fosters team cooperation.

A Retrospective Analysis of the Changes in Prediabetes-Associated Markers of Thyroid Function in Patients from Durban, South Africa

Thyroid dysfunction and type 2 diabetes melittus (T2DM) are two of the most common endocrine disorders, and the emerging condition of prediabetes necessitates additional research to better understand the complex interactions between thyroid hormones, metabolic regulation, and the progression from prediabetes to T2DM. This study sought to investigate changes in selected markers of thyroid function in patients with pre-diabetes. Upon obtaining ethics permission, blood samples were collected from patients in King Edward Hospital in Durban, South Africa. The samples were classified as non-diabetic, pre-diabetic, and type 2 diabetic using the ADA guidelines. The thyroid stimulating hormone (TSH), thyroxine (T4) triiodothyronine (T3), Thyroglobulin (TG), and thyroid peroxidase antibody (TPOAb) concentrations were determined in these samples. The results showed elevated TSH, decreased T3 and T4, decreased thyroglobulin (Tg), and elevated TPOAb in the prediabetic group which became considerably pronounced with the shift to T2DM. The alterations in these markers during prediabetes may indicate an early stage of thyroid dysfunction necessitating further investigation as these alterations become more pronounced during type 2 diabetes mellitus.

Immune indicators and depression in adolescents: Associations with monocytes, lymphocytes, and direct bilirubin

BACKGROUND

Depression is a significant psychiatric disorder with particularly high prevalence among adolescents. This mental health condition can have severe consequences, including academic failure, social withdrawal, and suicidal behavior. Given the increasing rate of depression in this age group, understanding the underlying biological mechanisms is essential for early detection and intervention. Recent studies have suggested that immune markers play a role in the pathophysiology of depression, prompting further investigation of their potential association with depressive symptoms in adolescents.

AIM

To investigate the relationship between immune markers (monocytes, lymphocytes, and direct bilirubin) and the incidence and severity of depression among adolescents.

METHODS

This cross-sectional study recruited 145 adolescent patients with depression [male (M)/female (F) = 38/107] from Jiangbin Hospital in Guangxi, Zhuang and 163 healthy controls (M/F = 77/86) from routine health check-ups. Blood samples were collected after an overnight fast. Depression severity was measured using the Zung Self-Rating Depression Scale. The inclusion criteria were age 12-24 years, diagnosis of depressive disorder (ICD-10), and no recent antidepressant use. The exclusion criteria included psychiatric comorbidities and serious somatic diseases. Key statistical methods included group comparisons and correlation analyses.

RESULTS

There was a higher prevalence of females in the depression group (P < 0.001). Significant age differences were observed between the groups (Z = 9.43, P < 0.001). The depression group had higher monocyte (Z = 3.43, P < 0.001) and lymphocyte (t = 2.29, P < 0.05) counts, and higher serum direct bilirubin levels (Z = 4.72, P < 0.001). Monocyte count varied significantly according to depression severity, with lower counts in the mild group (Z = -2.90, P < 0.05). A negative correlation between age and lymphocyte counts was observed (ρ = -0.22, P < 0.01). Logistic regression analysis showed that serum direct bilirubin levels significantly predicted depression.

CONCLUSION

The potential role of elevated levels of immune markers in the early detection of depression in adolescents has been highlighted. Therefore, it is necessary to explore further the relationships between these immune markers and depression.

Thyroid Stimulatory Activity of Houttuynia cordata Thunb. Ethanolic Extract in 6-Propyl-Thiouracil-Induced Hypothyroid and STZ Induced Diabetes Rats: In Vivo and In Silico Studies

Houttuynia cordata Thunb. holds a longstanding reputation as a traditional folk remedy in East Asia, where it has been employed to treat a variety of inflammatory conditions, nephritis, hepatitis and cancer. Despite its extensive use, there exists a paucity of research examining its efficacy in managing thyroid disorders and diabetes. Moreover, the bioactive components responsible for modulating the molecular pathways remain elusive.

OBJECTIVES

This research aimed to determine the key bioactive components in the ethanolic extract of H. cordata Thunb. (HCEE) responsible for its thyroid-modifying properties and examine its effects on rats with experimentally induced hypothyroidism and diabetes.

METHODS

Molecular docking was performed to investigate the possible mechanisms of thyroid regulation of HCEE constituents. Researchers induced hypothyroidism in rats by adding 6-propyl-2-thiouracil to their drinking water for a period of four weeks. To induce diabetes, the rats received an intraperitoneal injection of streptozotocin. The animals were then given daily oral doses of HCEE (500 mg/kg b.w.), levothyroxine (50 mg/kg b.w.), or glibenclamide (5 mg/kg b.w.) for 28 days. Following this treatment, standard methods were employed to measure biochemical parameters in the rats' serum.

RESULTS

The results demonstrate that HCEE ameliorated hypothyroidism by increasing serum T3 (14.38%) and T4 (125.96%) levels and decreasing TSH (p < 0.01; -41.75%) levels. In diabetic rats with induced hypothyroidism, HCEE significantly (p < 0.001) increased T3 (149.51%) and T4 (73.54%) levels with reduced TSH (-64.39%) levels. In silico analysis demonstrated that the identified bioactive compounds from HCEE may enhance thyroid hormone function through interaction with the thyroid hormone receptor protein TRβ1 (PDB:3GWS), similar to the conventional pharmaceuticals levothyroxine and triiodothyronine (T3).

CONCLUSIONS

HCEE exhibits potential as a natural alternative to synthetic medications in the prevention and treatment of thyroid dysfunctions.

Could Raman spectroscopy investigate the changes of cell oxidative stress status in thyroid diseases? A pilot study on cytological samples

The incidence of thyroid nodules is rapidly increasing worldwide. Raman spectroscopy (RS) is a powerful label-free and non-invasive technique, successfully used for early stage diagnosis. Here, RS is proposed as a tool to investigate the thyroid disease, including neoplasms, through the study of cell oxidative stress (OS), which represents one of the main cancer risk factors. In this study, we enrolled 28 patients, submitted to a first and second thyroid fine needle aspiration (FNA) during follow up. The cytological samples were studied by RS and morphological examination. Typical Raman spectra of thyroid cytological samples are reported and the contribution of oxidized and reduced cytochrome b and c and carotenoids are discussed. On the basis of the evolution of the Raman features over the time lapse between the two FNAs, the 28 patients have been classified into 4 different categories and the most representative case for each category is reported and discussed in detail. For each category, the different Raman intensity ratio between oxidized and reduced cytochromes b and c is reported and associated to different cell OS status, along with the presence of carotenoids. Overall, our results support a correlation among changes in oxidative stress, carotenoids uptake and thyroid diseases, which could inspire new fundamental research on biomarkers and signaling pathways involved in thyroid OS.

Exploring the application of dietary antioxidant index for disease risk assessment: a comprehensive review

Oxidative stress contributes to the development of cardiometabolic diseases and cancers. Numerous studies have highlighted the adverse effects of high reactive oxygen species (ROS) levels in the progression of chronic noncommunicable diseases and also during infections. On the other hand, antioxidants play a crucial role in preventing oxidative stress or postponing cell damage via the direct scavenging of free radicals or indirectly via the Keap1/Nrf2/ARE pathway, among others. Dietary antioxidants can be obtained from various sources, mainly through a plant-based diet, including fruits and vegetables. The dietary antioxidant index (DAI) has been developed to assess total antioxidant intake from diet. This review delineated the performance of DAI in the risk assessment of different diseases. It is suggested that a high DAI score prevents obesity-related diseases, including diabetes mellitus, hyperuricemia, dyslipidemia, and metabolic (dysfunction)-associated steatotic liver disease (MASLD). Additionally, DAI is negatively associated with Helicobacter pylori and Human papillomavirus infection, thus reducing the risk of gastric and cervical cancer. Also, a high intake of antioxidants prevents the development of osteoporosis, miscarriage, infertility, and mental illnesses. However, further prospective observations and clinical trials are warranted to confirm the application of DAI in preventing diseases that have been studied.

Recent advances in gut microbiota and thyroid disease: pathogenesis and therapeutics in autoimmune, neoplastic, and nodular conditions

This review synthesizes key findings from the past five years of experimental literature, elucidating the gut microbiome's significant influence on the pathogenesis of thyroid diseases. A pronounced shift in the gut microbiota composition has been consistently observed, with a significant reduction in bacteria such as Bifidobacterium, Bacillaceae, Megamonas, and Clostridium, and a notable increase in bacteria, including Bacteroides, Proteobacteria, Actinobacteria, Desulfobacterota, and Klebsiella. These alterations are implicated in the development and progression of thyroid diseases by impacting metabolic pathways including bile acid and cytokine production, including a decrease in short-chain fatty acids (SCFAs) that are crucial for immune regulation and thyroid hormone homeostasis. The review also highlights the therapeutic implications of probiotics in managing thyroid conditions. Evidence suggests that probiotic adjunct therapy can modulate the gut microbiota, leading to improvements in thyroid function and patient outcomes. The use of specific probiotic strains, such as Lactiplantibacillus plantarum 299v and Bifidobacterium longum, has demonstrated potential in enhancing the effects of traditional treatments and possibly restoring a balanced gut microbiota. Notably, fecal microbiota transplantation (FMT) has emerged as a promising intervention in Graves' Disease (GD), demonstrating the potential to recalibrate the gut microbiota, thereby influencing neurotransmitters and trace elements via the gut-brain and gut-thyroid axes. The integration of microbiome-based therapies with traditional treatments is anticipated to usher in a new era of personalized thyroid disease management, offering a more nuanced approach to patient care. By integrating this body of work, the review offers an innovative perspective on the gut microbiome's broad impact on thyroid diseases and the therapeutic applications of probiotics.

Antioxidant and neuro-modulatory effects of niacin prevent D-galactose-induced behavioral deficits and memory impairment

Aging is an invincible phenomenon that is a risk factor for the development of neurological disorders such as anxiety, depression, and memory decline that are prominent in aging. The present study aims to evaluate the effect of Niacin (Nn) on D-galactose (D-Gal)-induced behavioral deficits and memory impairment in rats. In the experiment, forty-eight male albino Sprague dwaley rats were divided on a random basis into six groups (n = 8): Veh + Veh, Veh + Nn (low dose), Veh + Nn (high dose), Veh + D-Gal, D-Gal+Nn (low dose), D-Gal+Nn (high dose). 300 mg/kg/mL drug doses of D-Gal, while low doses (25 mg/kg/mL) and high doses (50 mg/kg/mL) of Nn were used in this study. Animals received their respective treatment for 14 days (intraperitoneally, once daily). After 14 days, animals were subjected to different behavioral tests including light-dark box activity, elevated plus maze test (for anxiety), and tail suspension test (for depression). A Morris water maze test was performed to evaluate short-term and long-term memory performance. After behavioral tests, decapitation was performed and brains were collected and stored for biochemical and neurochemical analysis. Behavioral analysis revealed that Nn alleviated the anxiety and depression-like symptoms and memory decline induced by D-Gal. D-Gal-induced decreased antioxidant enzymes, and acetylcholine levels, while increased oxidative stress markers, neuro-inflammatory cytokines, serotonin metabolism, and acetylcholinesterase (AChE) activity were prevented by Nn administration at both doses. In-silico studies showed that Nn has a potential to inhibit AChE activity with a binding affinity of -5.0 kcal/mol. In conclusion, Nn as an antioxidant and neuromodulator could be helpful for treating aging and associated psychiatric illnesses.

Vitamin C in the Management of Thyroid Cancer: A Highway to New Treatment?

Thyroid cancer (TC) is the most common endocrine malignancy, with an increased global incidence in recent decades, despite a substantially unchanged survival. While TC has an excellent overall prognosis, some types of TC are associated with worse patient outcomes, depending on the genetic setting. Furthermore, oxidative stress is related to more aggressive features of TC. Vitamin C, an essential nutrient provided with food or as a dietary supplement, is a well-known antioxidant and a scavenger of reactive oxygen species; however, at high doses, it can induce pro-oxidant effects, acting through multiple biological mechanisms that play a crucial role in killing cancer cells. Although experimental data and, less consistently, clinical studies, suggest the possibility of antineoplastic effects of vitamin C at pharmacological doses, the antitumor efficacy of this nutrient in TC remains at least partly unexplored. Therefore, this review discusses the current state of knowledge on the role of vitamin C, alone or in combination with other conventional therapies, in the management of TC, the mechanisms underlying this association, and the perspectives that may emerge in TC treatment strategies, and, also, in light of the development of novel functional foods useful to this extent, by implementing novel sensory analysis strategies.

Impact of polyethylene microplastics exposure on kallikrein-3 levels, steroidal-thyroidal hormones, and antioxidant status in murine model: protective potentials of naringin

The widespread presence of microplastics in the environment has raised significant concerns regarding their potential impact on human and animal health. Among various microplastic types, polyethylene microplastics (PE-MPs) are particularly prevalent due to the extensive use in packaging and consumer products. Exploring the uncharted therapeutic potentials of naringin, this study delves into its mitigating effects on disruptions in kallikrein-3 levels, steroidal-thyroidal hormone balance, and antioxidant defense triggered by PE-MPs exposure, paving the way for novel interventions in environmental toxin-induced endocrine and oxidative stress disorders. Male Wistar rats (n = 24) were randomly grouped into four: Control, PE-MPs (1.5 mg/kg), PE-MPs + NAR (1.5 mg/kg PE-MPs + 100 mg/kg NAR), and NAR (100 mg/kg). Hormonal and antioxidant parameters were assessed after 28 days of exposure. PE-MPs exposure caused a significant increase(p < 0.005) in the level of kallikrein-3 (KLK-3) while it significantly reduces the levels of testosterone (TST), luteinizing hormone, thyroid stimulating hormone (TSH) and Free-triiodothyronine (fT3) and Total cholesterol (TChol) concentration. PE-MPs exposure also disrupted significantly (p < 0.005) antioxidant profile by down-regulating the activities of glutathione-S-transferase, catalase (CAT), superoxide dismutase (SOD) and reducing levels of glutathione (GSH) and ascorbic acid (AA) while concentration of malondialdehyde (MDA) levels were increased relative to control. However, the mitigating potentials of naringin on disruptions in hormonal and antioxidant profiles caused by PE-MPs exposure were demonstrated, as NAR normalized KLK-3, steroid, and thyroid hormone levels, cholesterol concentration, and enhanced antioxidant defense. This suggests that NAR is a promising protective agent against endocrine and oxidative damage induced by environmental contaminants such as microplastics.

The association between dietary inflammatory index and dietary total antioxidant capacity and Hashimoto's thyroiditis: a case-control study

BACKGROUND

Hashimoto's thyroiditis (HT) is an inflammatory disease characterized by increased reactive oxygen species. Diets rich in anti-inflammatory and antioxidant properties may be linked to a reduced risk of developing HT. The aim of this study was to investigate the association between the dietary inflammatory index (DII) and dietary total antioxidant capacity (DTAC) with HT in Iranian adults.

METHODS

The study was a hospital-based case-control study conducted on 230 participants (115 cases and 115 controls). Dietary intake was assessed using a food frequency questionnaire (FFQ). The FFQ data were used to calculate DII and DTAC scores. Anthropometric measurements, thyroid function, and antibody tests were evaluated using standard methods. Multivariable logistic regression analysis was performed in both raw and adjusted models to determine the association between DII and DTAC scores with HT.

RESULTS

The average age of the participants was 39.76 ± 9.52 years. The mean body mass index in the case and control groups was 28.03 ± 6.32 and 26.43 ± 5.13 (kg/m2), respectively (P = 0.036). In the HT group, the DII level was higher (P < 0.001) and the DTAC level was lower than those in the healthy group (P = 0.047). In the multivariable logistic regression model, after adjusting for confounding factors, subjects in the last tertile of DII had a nonsignificantly higher HT risk than those in the first tertile (OR = 1.75; 95% CI = 0.83-3.65; P = 0.130). Regarding DTAC, the subjects in the last tertile of DTAC had a significantly decreased risk of HT (OR = 0.47; 95% CI = 0.23-0.98; P = 0.043) compared to those in the first tertile. The DII had a positive correlation with anti-thyroid peroxidase antibody (anti-TPO), thyroglobulin antibodies (TG-Ab) and thyroid-stimulating hormone, while DTAC had a negative correlation with anti-TPO and TG-Ab (P < 0.050).

CONCLUSION

The increase in DII is not associated with an increase in the risk of HT, while DTAC can significantly reduce its risk. Having an anti-inflammatory and antioxidative diet can be effective in improving thyroid function. These conclusions should be confirmed in additional prospective studies.

Hypothyroxinaemia during gestation is associated with low ferritin and increased levels of inflammatory markers

Objective

Pregnancy is a state of physiological inflammation facilitating implantation. Early isolated hypothyroxinaemia (IH) and increased inflammation (including obesity) have been associated with severe obstetric complications. The current study evaluated the association between IH, low ferritin and inflammation parameters (interleukin 6 (IL-6), C-reactive protein (CRP), human chorionic gonadotrophin (hCG) and obesity. Moreover, the course of these parameters throughout pregnancy was evaluated in relation to IH.

Methods

In the cross-sectional study (A) at 12 weeks, 2759 women participated and 2433 participated in the longitudinal study (B) with assessments at 12, 20 and 28 weeks gestation. At the first trimester, 122 (4.4%) IH women (free thyroxine (FT4) <5th percentile, normal TSH levels) were compared with 2114 (76.6%) reference women (FT4 between tenth and 90th percentiles, normal thyrotrophin (TSH) levels), in study B these figures were 99 (4.1%) and 1847 (75.9%), respectively.

Results

Cross-sectionally, compared to reference women, IH was independently associated with low ferritin (<5th percentile, OR: 2.6, 95% CI: 1.4-4.9), high CRP (>95th percentile: OR: 1.9, 95% CI: 1.04-3.7), low hCG ( 30, OR: 1.7, 95% CI: 1.12.9) and higher age (OR: 1.1, 95% CI: 1.04-1.15). Longitudinally, compared to reference women, women with IH at 12 weeks gestation showed persistently and significantly lower ferritin and hCG levels, and persistently higher CRP and IL-6 levels throughout gestation.

Conclusion

Gestational IH could be viewed as a condition of increased inflammation, as reported in non-thyroidal illness syndrome. Less favourable inflammation parameters and low iron status during early gestation in IH women seem to persist throughout gestation.

The relationship between thyroid and human-associated microbiota: A systematic review of reviews

In recent years, a growing number of studies have examined the relationship between thyroid pathophysiology and intestinal microbiota composition. The reciprocal influence between these two entities has been proven so extensive that some authors coined the term "gut-thyroid axis". However, since some papers reported conflicting results, several aspects of this correlation need to be clarified. This systematic review was conceived to achieve more robust information about: 1)the characteristics of gut microbiota composition in patients with the more common morphological, functional and autoimmune disorders of the thyroid; 2)the influence of gut microbial composition on micronutrients that are essential for the maintenance of thyroid homeostasis; 3)the effect of probiotics, prebiotics and synbiotics, some of the most popular over-the-counter products, on thyroid balance; 4)the opportunity to use specific dietary advice. The literature evaluation was made by three authors independently. A five steps strategy was a priori adopted. After duplicates removal, 1106 records were initially found and 38 reviews were finally included in the analysis. The systematic reviews of reviews found that: 1) some significant variations characterize the gut microbiota composition in patients with thyroid disorders. However, geographical clustering of most of the studies prevents drawing definitive conclusions on this topic; 2) the available knowledge about the effect of probiotics and synbiotics are not strong enough to suggest the routine use of these compounds in patients with thyroid disorders; 3) specific elimination nutrition should not be routine suggested to patients, which, instead have to be checked for possible micronutrients and vitamins deficiency, often owed to gastrointestinal autoimmune comorbidities.

Melissa officinalis extract palliates redox imbalance and inflammation associated with hyperthyroidism-induced liver damage by regulating Nrf-2/ Keap-1 gene expression in γ-irradiated rats

BACKGROUND

Melissa officinalis (MO) is a well-known medicinal plant species used in the treatment of several diseases; it is widely used as a vegetable, adding flavour to dishes. This study was designed to evaluate the therapeutic effect of MO Extract against hyperthyroidism induced by Eltroxin and γ-radiation.

METHODS

Hyperthyroidism was induced by injecting rats with Eltroxin (100 µg/kg/ day) for 14 days and exposure to γ-radiation (IR) (5 Gy single dose). The hyperthyroid rats were orally treated with MO extract (75 mg/kg/day) at the beginning of the second week of the Eltroxin injection and continued for another week. The levels of thyroid hormones, liver enzymes and proteins besides the impaired hepatic redox status and antioxidant parameters were measured using commercial kits. The hepatic gene expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its inhibitor Kelch-like ECH-associated protein-1(Keap-1) in addition to hepatic inflammatory mediators including tumor necrosis factor-α (TNF- α), Monocyte chemoattractant protein-1 (MCP-1) and fibrogenic markers such as transforming growth factor-beta1 (TGF-β1) were determined.

RESULTS

MO Extract reversed the effect of Eltroxin + IR on rats and attenuated the thyroid hormones. Moreover, it alleviated hyperthyroidism-induced hepatic damage by inhibiting the hepatic enzymes' activities as well as enhancing the production of proteins concomitant with improving cellular redox homeostasis by attenuating the deranged redox balance and modulating the Nrf2/Keap-1 pathway. Additionally, MO Extract alleviated the inflammatory response by suppressing the TNF- α and MCP-1 and prevented hepatic fibrosis via Nrf2-mediated inhibition of the TGF-β1/Smad pathway.

CONCLUSION

Accordingly, these results might strengthen the hepatoprotective effect of MO Extract in a rat model of hyperthyroidism by regulating the Nrf-2/ Keap-1 pathway.

Harnessing the power of nutritional antioxidants against adrenal hormone imbalance-associated oxidative stress

Oxidative stress, resulting from dysregulation in the secretion of adrenal hormones, represents a major concern in human health. The present review comprehensively examines various categories of endocrine dysregulation within the adrenal glands, encompassing glucocorticoids, mineralocorticoids, and androgens. Additionally, a comprehensive account of adrenal hormone disorders, including adrenal insufficiency, Cushing's syndrome, and adrenal tumors, is presented, with particular emphasis on their intricate association with oxidative stress. The review also delves into an examination of various nutritional antioxidants, namely vitamin C, vitamin E, carotenoids, selenium, zinc, polyphenols, coenzyme Q10, and probiotics, and elucidates their role in mitigating the adverse effects of oxidative stress arising from imbalances in adrenal hormone levels. In conclusion, harnessing the power of nutritional antioxidants has the potential to help with oxidative stress caused by an imbalance in adrenal hormones. This could lead to new research and therapeutic interventions.

Tumor Microbial Communities and Thyroid Cancer Development-The Protective Role of Antioxidant Nutrients: Application Strategies and Future Directions

Thyroid cancer (TC), the most frequent malignancy of the endocrine system, has recorded an increasing incidence in the last decades. The etiology of TC remains at least partly unknown and, among modifiable risk factors, the gut microbiota and dietary nutrients (vitamins, essential microelements, polyphenols, probiotics) have been recognized to not only influence thyroid function, but exert critical effects on TC development and progression. Recent discoveries on the existence of tumor microbiota also in the TC microenvironment provide further evidence for the essential role of tumor microorganisms in TC etiology and severity, as well as acting as prognostic markers and as a potential target of adjuvant care in the treatment of TC patients. Therefore, in this review, we summarize current knowledge on the relationship of the tumor microbiome with the clinical tumor characteristics and TC progression, also illustrating the molecular mechanisms underlying this association, and how antioxidant nutrients may be used as a novel strategy to both control gut health and reduce the risk for TC. Furthermore, we discuss how new technologies might be exploited for the development of new foods with high nutritional values, antioxidant capability, and even attractiveness to the individual in terms of sensory and emotional features.

Environmental Endocrinology: Parabens Hazardous Effects on Hypothalamic-Pituitary-Thyroid Axis

Parabens are classified as endocrine-disrupting chemicals (EDCs) capable of interfering with the normal functioning of the thyroid, affecting the proper regulation of the biosynthesis of thyroid hormones (THs), which is controlled by the hypothalamic-pituitary-thyroid axis (HPT). Given the crucial role of these hormones in health and the growing evidence of diseases related to thyroid dysfunction, this review looks at the effects of paraben exposure on the thyroid. In this study, we considered research carried out in vitro and in vivo and epidemiological studies published between 1951 and 2023, which demonstrated an association between exposure to parabens and dysfunctions of the HPT axis. In humans, exposure to parabens increases thyroid-stimulating hormone (TSH) levels, while exposure decreases TSH levels in rodents. The effects on THs levels are also poorly described, as well as peripheral metabolism. Regardless, recent studies have shown different actions between different subtypes of parabens on the HPT axis, which allows us to speculate that the mechanism of action of these parabens is different. Furthermore, studies of exposure to parabens are more evident in women than in men. Therefore, future studies are needed to clarify the effects of exposure to parabens and their mechanisms of action on this axis.

A Literature Review and a Proposed Classification of the Relationships between Ovulatory Infertility and Lifestyle Factors Based on the Three Groups of Ovulation Disorders Classified by WHO

Ovulatory infertility is a serious clinical problem whose direct causes are still largely unknown. In addition to pathologies that make it impossible for a couple to establish a pregnancy, there are a number of other factors that have a bearing on fertility, including lifestyle factors, and particularly diet. Although numerous studies have been performed linking such factors to ovulatory infertility, most of them lack the necessary clinical significance, instead focusing on observational data and suggesting or establishing associative relationships. This article consists of a literature review focusing on connections between lifestyle factors such as diet, physical exercise, oxidative stress, sleep, and supplementation, and ovulatory infertility. Special emphasis was given to issues such as obesity and insulin resistance and their mutual relationship with other factors linked to ovulatory infertility. In addition, based on the conclusions of the literature review, the authors have proposed a classification of relationships between ovulation disorders and lifestyle factors in ovulatory infertility within the framework of the WHO classification of ovulation disorders. Furthermore, areas that merit further research have been indicated as well as those that do not. WHO Group II disorders gained prominence in the results of the study as the number of links with lifestyle factors and ovulatory infertility found in the course of the review greatly exceeded those for Groups I and III. The data presented in the article show that the issues of proper diet and physical exercise are those that could benefit from robust clinical studies focused specifically on ovulation infertility, while studies concerning the relationship between oxidative stress, sleep, and supplementation and ovulatory infertility do not seem to be promising directions as far as clinical significance is concerned.

The interplay of oxidative stress and immune dysfunction in Hashimoto's thyroiditis and polycystic ovary syndrome: a comprehensive review

In recent years, there has been a significant increase in the concomitant incidence of Hashimoto's thyroiditis (HT) and polycystic ovary syndrome (PCOS), both in terms of incidence, etiology, and clinical consequences. PCOS patients suffering from autoimmune thyroid diseases show insulin resistance, impaired glucose tolerance, weight gain, and metabolic and reproductive complications. Studies have shown that chronic stress and its consequence, i.e. oxidative stress, play an important role in the pathomechanism of both disorders. It has also been shown that long-term exposure to stress triggers biological mechanisms, in particular related to the regulation of the inflammatory cascade, which plays a key role in autoimmune diseases. The paper is a review of the literature on the role of chronic stress, oxidative stress, and immune processes in the pathogenesis of HT and PCOS. In addition, the review is a source of knowledge about the treatment of these diseases, and in particular the use of antioxidants in therapeutic management.