Thyroid disease and lipids

Persistent lipoprotein(a) exposure and its association with clinical outcomes after acute myocardial infarction: a longitudinal cohort study

AIMS

To assess the link between persistent lipoprotein(a) [Lp(a)] exposure levels and clinical outcomes in patients with acute myocardial infarction (AMI).

METHODS

This longitudinal cohort study included 1131 AMI patients, categorizing persistent Lp(a) exposure based on measurements at admission and after 1 year. Patients were segmented into four groups using a 300 mg/L Lp(a) threshold: (1) persistent low Lp(a) (lowon admission - lowat 1 year); (2) fortified Lp(a) (lowon admission - highat 1 year); (3) attenuated Lp(a) (highon admission - lowat 1 year); and (4) persistent high Lp(a) (highon admission - highat 1 year). Multivariate Cox regression, subgroup analysis and sensitivity analysis assessed the association between Lp(a) trajectories and major adverse cardiovascular and cerebrovascular events (MACCE), cardiovascular death, non-fatal MI, non-fatal stroke, unplanned revascularization, and all-cause death.

RESULTS

Over a median 50-month follow-up, 343 (35.70%) patients encountered MACCE, and 210 (18.70%) died, including 126 (11.20%) from cardiovascular causes. The group with persistent high Lp(a) faced increased risk of MACCE (HRadjusted, 1.871; 95% CI: 1.474-2.374), non-fatal stroke (HRadjusted, 1.647; 95% CI: 1.031-2.632), unplanned revascularization (HRadjusted, 1.571; 95% CI: 1.008-2.449), and both all-cause (HRadjusted, 1.546; 95% CI: 1.134-2.108) and cardiovascular death (HRadjusted, 2.163; 95% CI: 1.405-3.331), compared to the persistent low Lp(a) group.

CONCLUSIONS

In AMI patients, sustained high Lp(a) levels were significantly associated with increased risk of MACCE, non-fatal stroke, unplanned revascularization, and both all-cause and cardiovascular death.

Overnutrition directly impairs thyroid hormone biosynthesis and utilization, causing hypothyroidism, despite remarkable thyroidal adaptations

Thyroid hormones (THs: T 3 and T 4 ) are key regulators of metabolic rate and nutrient metabolism. They are controlled centrally and peripherally in a coordinated manner to elegantly match T 3 -mediated energy expenditure (EE) to energy availability. Hypothyroidism reduces EE and has long been blamed for obesity; however, emerging evidence suggests that, instead, obesity may drive thyroid dysfunction. Thus, we used a mouse model of diet-induced obesity to determine its direct effects on thyroid histopathology and function, deiodinase activity, and T 3 action. Strikingly, overnutrition induced hypothyroidism within 3 weeks. Levels of thyroidal THs and their precursor protein thyroglobulin decreased, and ER stress was induced, indicating that thyroid function was directly impaired. We also observed pronounced histological and vascular expansion in the thyroid. Overnutrition additionally suppressed T 4 activation, rendering the mice resistant to T 4 and reducing EE. Our findings collectively show that overnutrition deals a double strike to TH biosynthesis and action, despite large efforts to adapt-but, fortunately, thyroid dysfunction in mice can be reversed by weight loss. In humans, BMI correlated with thyroidal vascularization, importantly demonstrating initial translatability. These studies lay the groundwork for novel obesity therapies that tackle hypothyroidism-which are much-needed, as no current obesity treatment works for everyone.

Thyroid Hormones and Metabolism Regulation: Which Role on Brown Adipose Tissue and Browning Process?

Thyroid hormones (THs) are important modulators of many metabolic processes, being strictly associated with the control of energy balance, mainly through activities on the brain, white and brown adipose tissue, skeletal muscle, liver, and pancreas. In this review, the principal mechanisms of TH regulation on metabolic processes will be discussed and THs' relevance in metabolic disease progression will be evaluated, especially in the cardiovascular context and correlated diseases. Moreover, we will discuss THs' regulatory role on metabolic events in white and brown adipose tissue, with a special focus on the process of "browning", which consists of the gradual acquisition by white adipocytes of the physical and functional characteristics of brown adipocytes. The advancements in research on molecular mechanisms and proposed physiopathological relevance of this process will be discussed.

A comparative study on serum lipid levels in patients with thyroid dysfunction: a single-center experience in Ethiopia

BACKGROUND

Thyroid diseases are the most common endocrine disorders worldwide. Thyroid hormones are essential for lipid synthesis, metabolism, and mobilization. Lipid levels in the blood may be altered when there is thyroid dysfunction. Lipid changes are linked to hyperthyroidism and primarily involve total and low-density lipoprotein cholesterol. The serum lipid profile is negatively impacted by hypothyroidism, which may increase the risk of atherosclerotic disease development. Thus, hypothyroidism constitutes a significant cause of secondary dyslipidemia. However, the results obtained from different studies are inconsistent, and there are few data regarding lipid profiles in thyroid dysfunction patients in the study area. Therefore, this study aimed to assess the lipid profile of thyroid dysfunction patients at Wolaita Sodo University Comprehensive Specialized Hospital from May 1 to June 15, 2021.

METHODS

A comparative cross-sectional study was conducted involving 200 participants (100 thyroid dysfunction patients and 100 age- and sex-matched controls). Socio-demographic and related data were collected from the study participants via a pretested structured questionnaire through face-to-face interviews. Independent sample T tests and Mann‒Whitney U tests were used for data analysis. P < 0.05 indicated statistical significance.

RESULTS

Out of 200 study participants 40 (20%) hyperthyroid, 60 (30%) hypothyroidism, and 100 (50%) controls. In individuals with hyperthyroidism, the levels of triglycerides, total cholesterol, and low-density lipoprotein cholesterol were significantly lower than those in the control group. Compared to the control group, the hypothyroidism patients had significantly higher levels of triglycerides, low-density lipoprotein cholesterol, total cholesterol, and high-density lipoprotein cholesterol.

CONCLUSION

The lipid profile can change significantly as a result of thyroid dysfunction. Biochemical screening of lipid profiles is essential for improving patients with thyroid dysfunction with dyslipidemia.

Differential levels of thyroid hormones, cortisol, and apolipoprotein M in fatty liver disease

OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD), recently reclassified as metabolic dysfunction-associated fatty liver disease (MAFLD), can also manifest in patients classified as non-MAFLD who do not meet MAFLD criteria. The involvement of cortisol and thyroid hormones may play a role in the pathogenesis of FLD by modifying the metabolism of specific lipoproteins, particularly apolipoprotein M (Apo M). This study investigated cortisol and thyroid hormones levels and Apo M gene expression in white blood cells (WBCs) of individuals with MAFLD, non-MAFLD, and healthy controls.

METHODS

The serum and WBCs of the study subjects were collected from patients with FLD (n=99) including 58 MAFLD and 41 non-MAFLD and healthy individuals (n=23). To investigate the gene expression of Apo M and thyroid and cortisol hormones, qRT-PCR and ELISA methods were used, respectively.

RESULTS

The Apo M gene expression was significantly lower in FLD patients, both non-MAFLD, and MAFLD patients compared to the control group (p<0.05). Total T4 and TSH hormone levels in the MAFLD patients were significantly decreased and increased compared to the control group, respectively (p<0.05). The cortisol level was significantly elevated in the FLD and MAFLD patients compared to the control group (p<0.01).

CONCLUSIONS

Alterations in Apo M gene expression also cortisol and thyroid hormones levels in non-MAFLD patients were milder than MAFLD patients when compared to the control. Also, likely Apo M may be involved in FLD pathogenesis.

Comparing Outcomes of Moyamoya Disease and Moyamoya Syndrome in a Real-World Scenario: A Cohort Study

BACKGROUND

Moyamoya disease (MMD) and moyamoya syndrome (MMS) are rare cerebrovascular conditions with unclear distinctions in clinical presentation and prognosis.

AIM

This study assessed potential differences between MMD and MMS patients using real-world data on clinical manifestations, surgical outcomes, and stroke risk factors.

METHODS

This multicenter, retrospective cohort study examined patients with MMD or MMS treated at three tertiary academic hospitals in China, with a mean follow-up of 11.2 ± 3.1 years. Clinical differences were compared between MMD and MMS, and postoperative cerebrovascular events were compared between patients who underwent surgery and those with conservative management. Primary outcomes were postoperative ischemic and hemorrhagic strokes. Risk factors were evaluated via multivariate Cox regression analysis.

RESULTS

Of the 2565 patients, 2349 had MMD and 216 had MMS. After 1:1 propensity-score matching, no significant differences were observed between these two cohorts. Surgical patients had fewer cerebrovascular events than those who received conservative treatment (HR, 0.487; 95% CI, 0.334-0.711; p < 0.001). Preadmission modified Rankin scale scores > 2 (HR, 3.139; 95% CI, 1.254-7.857; p = 0.015) and periprocedural complications (HR, 8.666; 95% CI, 3.476-21.604; p < 0.001) were independent stroke risk factors in patients with MMD. Periprocedural complications (HR, 31.807; 95% CI, 10.916-92.684; p < 0.001) increased stroke risk in patients with MMS.

CONCLUSIONS

This real-world study revealed substantial clinical overlap between MMD and MMS. Both groups derived significant benefits from surgical revascularization, suggesting distinction may not be necessary to guide surgical management decisions. Optimizing preoperative status and preventing periprocedural complications may improve outcomes in these rare cerebrovascular conditions.

TRIAL REGISTRATION

This study has been registered in the Chinese Clinical trial registry (registration number: ChiCTR2200064160).

Preliminary investigations of plasma lipidome and selenium levels in adults with treated hypothyroidism and in healthy individuals without selenium deficiency

The present preliminary study aimed to provide a targeted lipidomic analysis of Hashimoto (HT) and non-HT patients with well-controlled hypothyroidism as well as in healthy adults, and is the first to demonstrate the association of several components of the human lipidome with hypothyroidism in relation to the total plasma selenium content. All the patients and age-, sex-, and BMI-matched healthy controls met the very strict qualification criteria. Se levels were analyzed by ICP-MS, and lipidome studies were conducted using TQ-LC/MS. The 40 acylcarnitines, 90 glycerophospholipids, and 15 sphingomyelins were identified and quantified. PCaaC26:0 and PCaaC40:1 were negatively correlated with Se concentrations. Other lipids that were negatively correlated with Se concentrations but did not present significant differences between the three groups in the Kruskal-Wallis ANOVA test were PCaaC32:0, PCaeC30:0, PCaeC36:5, SMC18:0, and SM C18:1. In the multiple linear regression analyses, Se levels showed negative relationship, whereas different phosphatidylcholines: PCaaC24:0, PCaaC26:0, PCaeC30:1, PCaeC34:0, PCaeC36:4, PCaeC42:0 were positively associated with the presence of (H). Different lipidome components were identified in healthy and hypothyroid patients regardless of the cause of that condition. Studies on larger populations are needed to determine cause-and-effect relations and the potential mechanisms underlying these associations.

Novel Insights into Causal Effects of Lipid and Lipid-Lowering Targets with Autoimmune Thyroid Disease: A Mendelian Randomization Study

Background

Dyslipidemia has been implicated in the pathogenesis of several diseases, including thyroid dysfunction and immune disorders. However, whether circulating lipids and long-term use of lipid-lowering drugs influence the development of autoimmune thyroid disease (AITD) remains unclear. This study aims to evaluate the effects of lipid-lowering drugs on AITD and explore their potential mechanisms.

Methods

Two-sample and two-step Mendelian randomization (MR) studies were performed to assess the causal relationships between circulating lipids (LDL-C, TC, TG, and ApoB) and seven lipid-lowering drug targets (ApoB, CETP, HMGCR, LDLR, NPC1L1, PCSK9, and PPARα) with AITD. Mediation analyses were conducted to explore potential mediating factors.

Results

There was no clear causality between circulating lipids (ApoB, LDL-C, TC, and TG) and AITD (p > 0.05). ApoB inhibition is related to a reduced risk of autoimmune thyroiditis (AT) (OR = 0.462, p= 0.046), while PCSK9 inhibition is related to reduced Graves' disease (GD) risk (OR = 0. 551, p = 0.033). Moreover, PCSK9 inhibition (OR = 0.735, p = 0.003), LDLR inhibition (OR = 0.779, p = 0.027), and NPC1L1 inhibition (OR = 0.599, p = 0.016) reduced the risk of autoimmune hypothyroidism (AIH). Mediation analysis showed that NPC1L1 inhibition and PCSK9 inhibition exerted effects on AIH through IL-4 and FGF-19 levels. And the effect of PCSK9 inhibition on GD through TNF-β levels.

Conclusion

There was no clear causality between circulating lipids (ApoB, LDL-C, TC, and TG) and AITD. Lipid-lowering drug target gene inhibitors reduced the AITD risk by modulating inflammatory factors.

Application of Human Plasma Targeted Lipidomics and Analysis of Toxic Elements to Capture the Metabolic Complexities of Hypothyroidism

BACKGROUND

Hypothyroidism (HT) affects millions worldwide and can lead to various lipid disorders. The metabolic complexity and the influence of toxic elements in autoimmune and non-autoimmune HT subtypes are not fully understood. This study aimed to investigate the relationships between plasma lipidome, toxic elements, and clinical classifications of HT in unexposed individuals.

METHODS

Samples were collected from 120 adults assigned to a study group with Hashimoto's disease and non-autoimmune HT, and a healthy control group. Quantification of 145 pre-defined lipids was performed by using triple quadrupole tandem mass spectrometry (TQ MS/MS) in multiple reactions monitoring (MRM) mode via positive electrospray ionization (ESI). Levels of toxic elements were determined using inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

Significant associations between altered levels of several components of the plasma lipidome and Al, Cd, Ni, As, and Pb with HT were found. We show metabolic differences in lysophosphatidylcholines (LPC) and phosphatidylcholines (PC) between HT and controls, with distinct predicted activation patterns for lysolecithin acyltransferase and phospholipase A2.

CONCLUSIONS

There are significant changes in the lipidome profiles of healthy subjects compared to euthyroid HT patients treated with L-thyroxine, which are related to the type of hypothyroidism and non-occupational exposure to toxic elements.

The non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) is associated with thyroid hormones and thyroid hormone sensitivity indices: a cross-sectional study

BACKGROUND

Lipids and thyroid hormones (TH) are closely interrelated. However, previous studies have not mentioned the linkage encompassing the non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) alongside TH level, as well as sensitivity indices.

METHODS

This cross-sectional study leverages expansive datasets from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2012. Weighted multivariate linear regression, smoothed curve fitting and sensitivity analyses were used to investigate the associations of the NHHR with the thyroid. Subgroup analyses and interaction tests were conducted to determine the robustness of the findings across diverse segments of the population, ensuring the consistency and generalizability of the observed associations.

RESULTS

The NHHR was significantly positively correlated with free triiodothyronine (FT3) levels, thyroid-stimulating hormone (TSH) levels, the FT3 to FT4 ratio (FT3/FT4), and the quantile-based thyroid feedback index for FT3 (TFQIFT3) and negatively correlated with free thyroxin (FT4) levels [0.17(0.07-0.27), P = 0.001; 0.60 (0.03-1.17), P = 0.040; 0.06 (0.04-0.08), P < 0.0001; 0.23 (0.16-0.30), P < 0.0001; and -0.65 (-1.05--0.24), P = 0.002]. Smoothed curve fitting revealed nonlinear correlations of the NHHR with thyroid function and thyroid hormone sensitivity indices. In subgroup analyses, interaction tests, and smoothed curve fitting analyses, different populations presented largely consistent statistical differences.

CONCLUSION

Among American adults, the NHHR was significantly positively correlated with FT3 levels, TSH levels, the FT3/FT4 and the TFQIFT3. Conversely, a negative association was noted between the NHHR and FT4 levels.

Assessment of Cardiometabolic Risk Factors and Insulin Sensitivity by Hyperinsulinemic-Euglycemic Clamp in Resistance to Thyroid Hormone β Syndrome

Background: Resistance to thyroid hormone beta (RTHβ) is a rare disease resulting from mutations in the THRB gene, characterized by reduced T3 action in tissues with high thyroid hormone receptor β expression. Thyroid hormones regulate body composition and metabolism in general, and increased or decreased hormone levels are associated with insulin resistance. This study evaluated the presence of cardiometabolic risk factors and insulin sensitivity in patients with RTHβ. Methods: In all, 16 patients, 8 adults (52.3 ± 16.3 years of age) and 8 children (10.9 ± 3.9 years of age), were compared to 28 control individuals matched for age, sex, and body mass index (BMI). Anthropometry evaluation and blood samples were collected for glycemia, lipids, insulin, interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), leptin, adiponectin, ultrasensitive C-reactive protein (CRPus), free thyroxine, total triiodothyronine, thyrotropin, and anti-thyroid peroxidase measurements. Body composition was assessed using dual-emission X-ray absorptiometry and bioimpedance. Insulin sensitivity was evaluated in adult patients and controls using the hyperinsulinemic-euglycemic clamp (HEC), whereas homeostasis model assessment of insulin resistance (HOMA-IR) was calculated in all individuals studied. Results: Patients and controls presented similar weight, BMI, abdominal perimeter, and total fat body mass. Patients with RTHβ demonstrated higher total cholesterol (TC), p = 0.04, and low-density lipoprotein cholesterol (LDL-C), p = 0.03, but no alteration was observed in other parameters associated with metabolic risk, such as leptin, TNF-α, and CRPus. Two adult patients met the criteria for metabolic syndrome. There was no evidence of insulin resistance assessed by HEC or HOMA-IR. Elevated IL-6 levels were observed in patients with RTHβ. Conclusion: Using HEC as the gold standard method, no evidence of reduced insulin sensitivity in skeletal muscle was documented in RTHβ adult patients; however, higher levels of TC and LDL-C were observed in these patients, which suggest the need for active monitoring of this abnormality to minimize cardiometabolic risk. In addition, we demonstrated, for the first time, that the increase in IL-6 levels in patients with RTHβ is probably secondary to metabolic causes as they have normal levels of TNF-α and CRPus, which may contribute to an increase in cardiovascular risk. A larger number of patients must be studied to confirm these results.

The key roles of thyroid hormone in mitochondrial regulation, at interface of human health and disease

Mitochondria are highly plastic and dynamic organelles long known as the powerhouse of cellular bioenergetics, but also endowed with a critical role in stress responses and homeostasis maintenance, supporting and integrating activities across multifaced cellular processes. As a such, mitochondria dysfunctions are leading causes of a wide range of diseases and pathologies. Thyroid hormones (THs) are endocrine regulators of cellular metabolism, regulating intracellular nutrients fueling of sugars, amino acids and fatty acids. For instance, THs regulate the balance between the anabolism and catabolism of all the macro-molecules, influencing energy homeostasis during different nutritional conditions. Noteworthy, not only most of the TH-dependent metabolic modulations act via the mitochondria, but also THs have been proved to regulate the mitochondrial biosynthesis, dynamics and function. The significance of such an interplay is different in the context of specific tissues and strongly impacts on cellular homeostasis. Thus, a comprehensive understanding of THs-dependent mitochondrial functions and dynamics is required to develop more precise strategies for targeting mitochondrial function. Herein, we describe the mechanisms of TH-dependent metabolic regulation with a focus on mitochondrial action, in different tissue contexts, thus providing new insights for targeted modulation of mitochondrial dynamics.

Effect of Levothyroxine Therapy on the Lipid Profile of Patients With Hypothyroidism: A Systematic Review

Hypothyroidism, also known as underactive thyroid, is a condition where the thyroid gland does not produce enough thyroid hormone. Deficiency or lack of thyroid hormone causes patients to have a slower metabolism, which may lead to secondary medical issues such as weight gain, fatigue, depression, and increased cardiovascular risk. This systematic review aims to explore the effect of levothyroxine therapy on the lipid profile of hypothyroid patients. Through a comprehensive search, 3096 articles were retrieved using keywords such as Hypothyroidism, Levothyroxine, Lipid, Dyslipidemia, and Cholesterol from PubMed, PubMed Central, Google Scholar, and ScienceDirect databases. The Medical Subject Headings (MeSH) strategy was also leveraged to extensively search the PubMed database. Research articles that were published from the year 2020 until May 2024, including randomized control trials, observational studies, meta-analyses, systematic reviews, literature reviews, and case reports, were included in the research. Research papers published before 2020, written in languages other than English, and animal studies were excluded. The 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria were used in the design of the systematic review. Levothyroxine therapy is the treatment of choice in patients suffering from hypothyroidism, and based on our review, the treatment has a positive impact, leading to a significant decrease in total cholesterol, low-density lipoproteins, and triglyceride values in hypothyroid patients. The research highlights the importance of starting timely levothyroxine therapy in hypothyroid patients to maintain normal lipid levels and reduce the associated cardiovascular risk.

Serum metabolome analysis in hyperthyroid cats before and after radioactive iodine therapy

Hyperthyroidism is the most common feline endocrinopathy. In hyperthyroid humans, untargeted metabolomic analysis identified persistent metabolic derangements despite achieving a euthyroid state. Therefore, we sought to define the metabolome of hyperthyroid cats and identify ongoing metabolic changes after treatment. We prospectively compared privately-owned hyperthyroid cats (n = 7) admitted for radioactive iodine (I-131) treatment and euthyroid privately-owned control (CON) cats (n = 12). Serum samples were collected before (T0), 1-month (T1), and three months after (T3) I-131 therapy for untargeted metabolomic analysis by MS/MS. Hyperthyroid cats (T0) had a distinct metabolic signature with 277 significantly different metabolites than controls (70 increased, 207 decreased). After treatment, 66 (T1 vs. CON) and 64 (T3 vs. CON) metabolite differences persisted. Clustering and data reduction analysis revealed separate clustering of hyperthyroid (T0) and CON cats with intermediate phenotypes after treatment (T1 & T3). Mevalonate/mevalonolactone and creatine phosphate were candidate biomarkers with excellent discrimination between hyperthyroid and healthy cats. We found several metabolic derangements (e.g., decreased carnitine and α-tocopherol) do not entirely resolve after achieving a euthyroid state after treating hyperthyroid cats with I-131. Further investigation is warranted to determine diagnostic and therapeutic implications for candidate biomarkers and persistent metabolic abnormalities.

Hypothyroidism and metabolic cardiovascular disease

Cardiovascular disease (CVD) remains the leading cause of death worldwide, representing a major health issue of social and economic relevance. Both hyperthyroidism and hypothyroidism are very common in the adult population, and both disorders may contribute to the onset and progression of CVD. After a brief description of the role of thyroid hormones (THs) on the physiology of the cardiovascular system and the potential mechanism that links THs alterations with changes in cardiac function, blood pressure, endothelial function, and lipid levels, we review updated data about the clinical impact of overt hypothyroidism (OH) and subclinical hypothyroidism (SCH) on CV risk, CVD, and mortality. Furthermore, we summarize the current evidence for treating SCH with levothyroxine (L-T4). Several guidelines of distinguished endocrine societies recommend treatment for SCH with TSH higher than 10 mIU/L, where the benefit of L-T4 therapy is more evident for younger people, but still controversial in those aged over 65 years. Based on current knowledge, more research efforts are needed to better address the clinical management of CV risk and CVD in the elderly affected by SCH.

Visceral Fat Area and Subcutaneous Fat Area Increase in Hyperthyroidism Patients After Treatment-A Single-Group Repeated-Measures Trial

Purpose

There is evidence that long-term vascular risk remains increased in patients with hyperthyroidism even after normalization of thyroid function, and the mechanisms that regulate this risk are unclear. The aim of this study was to assess how visceral fat area and subcutaneous fat area change after hyperthyroidism treatment, and to further explore the relationship between thyroid hormones, abdominal fat area (visceral fat area and subcutaneous fat area), and lipids.

Patients and Methods

50 patients with newly diagnosed Graves' disease were selected. Anthropometric parameters (weight, height, body mass index, waist circumference, neck circumference), laboratory parameters (thyroid hormones, lipid metabolism indices), abdominal fat area (visceral fat area and subcutaneous fat area), and drug dose were collected. Measurements were made at baseline, 6 and 12 months after treatment. We used linear mixed-effects models for analysis.

Results

The results showed that the following indexes changed significantly at different time points: visceral fat area, subcutaneous fat area, free triiodothyronine, free thyroxine, thyroid stimulating hormone, total cholesterol, high-density lipoprotein, low-density lipoprotein, body weight, neck circumference, body mass index, waist circumference, and drug dose (All P<0.001). We found that free triiodothyronine and free thyroxine were significantly negatively associated with abdominal fat area (P<0.01). There was no significant correlation between drug dose and abdominal fat area (P>0.05). Total cholesterol and low-density lipoprotein were significantly positively associated with abdominal fat area (P<0.01). However, high-density lipoprotein (P=0.06) was not correlated with abdominal fat area. Moreover, the results showed a significant negative correlation between thyroid hormones and lipids (P<0.001).

Conclusion

After anti-thyroid medicine treatment, patients had elevated visceral fat area and subcutaneous fat area and altered lipid profiles. These changes may be one of the reasons why metabolic and cardiovascular diseases remain increased after thyroid function is restored.

Impaired Thyroid Hormone Sensitivity Increases Risk of Cardiovascular Events in Patients Undergoing Coronary Angiography

CONTEXT

Previous studies found inconsistent results on the relationship between thyroid function and cardiovascular risks.

OBJECTIVE

This study aimed to investigate the association of thyroid hormone sensitivity with the risk of major adverse cardiovascular events (MACE) and cardiovascular death in a euthyroid population undergoing coronary angiography.

METHODS

This prospective cohort study enrolled 1470 euthyroid participants who underwent coronary angiography between March and November of 2013. The participants were followed up from July to November in 2022. Thyrotroph thyroxine resistance index (TT4RI), TSH index (TSHI), and feedback quantile-based index (TFQI) were calculated to evaluate the sensitivity to thyroid hormone. Kaplan-Meier curve and multivariable Cox proportional hazard model were performed to analyze the association between thyroid hormone sensitivity and risk of MACE and cardiovascular death.

RESULTS

Among 1089 participants who completed the follow-up, 342 cases of MACE and 77 cardiovascular deaths were identified during a medium follow-up duration of 111 months. In the multivariable Cox proportional hazard model, the higher levels of TFQI (hazard ratio [HR] = 1.41; 95% CI, 1.08-1.84; P for trend = .01), TT4RI (HR = 1.40; 95% CI, 1.06-1.84; P for trend = .02) and TSHI (HR = 1.61; 95% CI, 1.22-2.13; P for trend = .001) were associated with increased risk of MACE. The higher levels of TFQI (HR = 2.21; 95% CI, 1.17-4.17; P for trend = .02) and TSHI (HR = 2.05; 95% CI; 1.08-3.91; P for trend = .03) were also associated with increased risk of cardiovascular death.

CONCLUSION

Impaired sensitivity to thyroid hormone is associated with higher risks of MACE and cardiovascular death in a euthyroid population undergoing coronary angiography.

Genetic insights into repurposing statins for hyperthyroidism prevention: a drug-target Mendelian randomization study

Background

Current therapeutic measures for thyroid dysfunction are limited and often accompanied by adverse effects. The use of lipid-lowering drugs like statins has recently been associated with lower thyroid eye diseases risk.

Objective

To investigate the implications of genetically proxied lipid-lowering drugs on thyroid dysfunction.

Methods

In this drug-target Mendelian randomization (MR) study, we utilized genetic variants within drug target genes associated with low-density lipoprotein (LDL) or triglyceride (TG), derived from a genome-wide association study (GWAS) meta-analysis (N ≤ 188,577), to simulate lifelong drug interventions. Genetic summary statistics for thyroid dysfunction outcomes were retrieved from GWAS datasets of Thyroid Omics Consortium (N ≤ 54,288) and UK Biobank (N = 484,598). Inverse-variance-weighted MR (IVW-MR) method was performed as primary analysis, followed by validation in colocalization analysis. A subsequent two-step MR analysis was conducted to identify biomarkers mediating the identified drug-outcome association.

Results

In IVW-MR analysis, genetic mimicry of 3-hydroxy-3-methylglutarylcoenzyme reductase (HMGCR) inhibitors (e.g. statins) was significantly associated with lower risk of hyperthyroidism in two independent datasets (OR1, 0.417 per 1-mmol/L lower in LDL-C; 95% CI 0.262 to 0.664; P1 = 2.262 × 10-4; OR2 0.996; 95% CI 0.993-0.998; P2 = 0.002). Two-step MR analysis revealed eighteen biomarkers linked to genetic mimicry of HMGCR inhibition, and identified insulin-like growth factor 1 (IGF-1) levels mediating 2.108% of the negative causal relationship between HMGCR inhibition and hyperthyroidism.

Conclusion

This study supports HMGCR inhibition as a promising therapeutic strategy for hyperthyroidism and suggests its underlying mechanisms may extend beyond lipid metabolism. Further investigations through laboratory studies and clinical trials are necessary to confirm and elucidate these findings.

Serum Lipoprotein(a) Is Not Associated with Graves' Ophthalmopathy

Aim: To investigate the relationship of serum lipoprotein(a) [Lp(a)] and other serum lipids with presence of Graves' ophthalmopathy (GO). Methods: A total of 99 consecutive patients diagnosed with Graves' disease (GD), aged 18-65 years, who had not received prior treatment for GO, thyroid surgery, or radioactive iodine therapy, were recruited between June 2020 and July 2022. In addition, 56 healthy controls (HCs) were included as the control group. All patients underwent an ophthalmological examination, and were classified based on the presence of GO into the GO group (n = 45) and no GO group (n = 54). Fasting blood samples were collected from all participants to analyze serum lipid parameters, including Lp(a), total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides. Results: The median serum levels of Lp(a) were 5.7 [4.3-9.2] in the GO group, 6.7 [3.7-9.9] in the no GO group, and 4.7 [3-7.6] in the HC group. The intergroup comparisons of serum Lp(a) levels showed no significant result. The serum levels of total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides were also similar between the groups (P > 0.05 for all). However, when analyzing only euthyroid GD patients and the control group, the serum LDL cholesterol levels were found to be significantly higher in the euthyroid GO group [median: 132 interquartile range (IQR) (110-148) mg/dL] than in the HCs [median: 96 IQR (94-118) mg/dL] (P = 0.002). Conclusion: The findings of our study did not support the association between serum Lp(a) levels and GO.

Elevated triglycerides and low triiodothyronine: Key risk factors for coronary artery calcification in patients with schizophrenia

OBJECTIVE

Coronary artery calcification (CAC) is a well-established independent predictor of coronary heart disease, and patients with schizophrenia have significantly higher rates compared to the general population. We performed this study to examine the population-specific risk factors associated with CAC in patients with schizophrenia.

METHODS

In this cross-sectional study, patients with schizophrenia who underwent low-dose chest CT scans between January 2020 and December 2021 were analyzed. Ordinary CAC scores and results of routine blood tests were obtained. Logistic regression was used to calculate the odds ratio (OR) for potential risk factors in patients with and without CAC, while the negative binomial additive model was used to explore the dose-response relationship between risk factors and CAC score.

RESULTS

Of the 916 patients, 233 (25.4 %) had CAC, while 683 (74.6 %) did not. After adjusting for confounding factors, higher triglyceride levels (OR = 1.20, 95 % confidence interval (CI): 1.04 to 1.38, p = 0.013) and low triiodothyronine levels (OR = 0.50, 95 % CI: 0.29 to 0.84; p = 0.010) were identified as risk factors for CAC. Both triglycerides (p = 0.021) and triiodothyronine (p = 0.010) were also found to have significant dose-response relationships with CAC scores according to the negative binomial additive model in the exploratory analysis.

CONCLUSIONS

This study highlights elevated serum triglycerides and decreased triiodothyronine levels as population-specific risk factors for CAC in patients with schizophrenia, suggest the need for close monitoring of CAC in patients with schizophrenia and further prospective trials to provide additional evidence on this topic.

Thyroid Disorders and Peripheral Arterial Disease

Hypothyroidism and hyperthyroidism, both overt and subclinical, are associated with increased risk of cardiovascular morbidity and mortality. The association between thyroid-stimulating hormone levels and cardiovascular risk has been demonstrated in large epidemiological studies and meta-analyses and is now considered a U-shaped curve. Several pathophysiological mechanisms linking thyroid and cardiovascular disease are known; however, specific clinical complications of peripheral arterial disease as endpoints of clinical trials have not been adequately investigated. The potential mechanisms linking hypothyroidism and peripheral arterial disease are endothelial dysfunction, blood pressure changes, dyslipidemia, and low-grade systemic inflammation. The potential mechanisms linking hyperthyroidism and peripheral arterial disease are hyperdynamic circulation, elevated systolic blood pressure, hypercoagulability, and possibly increased arterial inflammation.

Prevalence of dyslipidemia and the association with levels of TSH and T4 hormones among patients in south region of Jordan

BACKGROUND

Glycolipid metabolism disorders (dysglycolipidemia) are characterized by elevated levels of glycolipid profile components and fasting blood glucose. Dysglycolipidemia are major threats to human health and life. Therefore, the aim of this cross-sectional study is to estimate the prevalence of dysglycolipidemia and the existence of association of TSH and T4 and glycolipid profiles.

METHODS

Cross-sectional data were obtained from the medical laboratory of Ma'an Governmental Hospital. A total of 141 patients' results were collected (18-60 years). Differences in the glycolipidemic profiles according to age and sex and TSH and T4 were compared. Different statistical analyses were used to analyze the prevalence of dysglycolipidemia and the correlation with the levels of TSH and T4.

RESULTS

The study involved results of 141 patients (54.7% males and 45.3% females) in Ma'an Province (Jordan), who visited the internal medicine clinic at Ma'an Governmental Hospital. Patients have overweight and BMI of more than 25 kg/m2. The overall results of the prevalence of dyslipidemia indicated that patients have 42.5% of hypercholesterolemia, 48.2% of high LDL-C, 34.1% of hypertriglyceridemia, and 41.8% of low HDL-C. The prevalence of isolated lipid profiles showed that 10 patients have mixed dyslipidemia. The association of dyslipidemia with age indicated a positive significance between triglyceride and older people (≥40 years), while HDL levels have a significance with gender (p=0.025). The overall ANOVA model yielded non-statistical significant results between levels of any components of lipid profile and levels of TSH and T4 hormones. Welch test (p=0.036) showed positive significance between levels of fasting blood glucose and triglyceride levels.

CONCLUSIONS

Our results showed and confirmed the presence of a high percentage of hyperlipidemia in Ma'an province and there was no relationship with levels of TSH and T4. A relationship exists between levels of triglycerides and blood glucose concentrations.

Gallstone Disease and Its Correlation With Thyroid Disorders: A Narrative Review

Over the years, several studies have revealed an important link between thyroid disorders and gallstone disease. According to these studies, hypothyroidism and hyperthyroidism are associated with cholesterol gallstone disease. This association between thyroid hormone disorders and cholesterol gallstone disease is due to the importance of thyroid hormones on cholesterol synthesis, bile functioning and content, and gallbladder motility. Several genes and receptors have been found on the thyroid gland, liver, and gallbladder to verify this association. These genes affect thyroid hormone secretion, lipid metabolism, and bile secretion. Defects in these various gene expression and protein functions lead to bile duct diseases. Other causes that lead to cholesterol gallstone disease are supersaturation of the bile with cholesterol and impaired gallbladder motility, which leads to bile stasis. This article has discussed these factors in detail while highlighting the association between thyroid hormones and cholesterol gallstone disease.

Approach to the Patient With a Suboptimal Statin Response: Causes and Algorithm for Clinical Management

CONTEXT

Statins are the lipid-lowering therapy of choice for the prevention of atherosclerotic cardiovascular disease (ASCVD) but their effectiveness in lowering low-density lipoprotein cholesterol (LDL-C) can substantially differ between individuals. In this mini-review, we describe the different causes for a suboptimal statin response and an algorithm for the diagnosis and clinical management of these patients.

EVIDENCE ACQUISITION

A PubMed search using the terms "statin resistance," "statin sensitivity," "statin pharmacokinetics," "cardiovascular disease," and "lipid-lowering therapies" was performed. Published papers in the past 10 years that were relevant to the topic were examined to provide content for this mini-review.

EVIDENCE SYNTHESIS

Suboptimal lowering of LDL-C by statins is a major problem in the clinical management of patients and limits the value of this therapeutic approach. There are multiple causes of statin hyporesponsiveness with compliance being the most common explanation. Other causes, such as analytical issues with LDL-C measurement and the presence of common lipid disorders (familial hypercholesterolemia, elevated lipoprotein[a] and secondary dyslipidemias) should be excluded before considering primary statin resistance from rare genetic variants in lipoprotein-related or drug-metabolism genes. A wide variety of nonstatin lipid-lowering drugs are now available and can be added to statins to achieve more effective LDL-C lowering.

CONCLUSIONS

The evaluation of statin hyporesponsiveness is a multistep process that can lead to the optimization of lipid-lowering therapy for the prevention of ASCVD. It may also lead to the identification of distinct types of dyslipidemias that require specific therapies and/or the genetic screening of family members.

Dyslipidemia in Pediatric Patients: A Cross-Sectional Study

There is an increasing interest in dyslipidemia in adult patients since it is known to contribute to early cardiovascular disease. Often, dyslipidemia starts in childhood, and it is associated with aggravating lifestyle choices concerning eating habits, such as the tendency to consume processed food and fast food, as well as the tendency to be more and more sedentary. We conducted a retrospective cross-sectional study describing the prevalence of dyslipidemia in a single medical center in Romania and the associated pathology. We evaluated all lipid profiles that were ordered in our clinic over nine years. We included 2413 patients that were evaluated in our clinic in the timeframe 2011-2020. Out of them, 18.23% had high values for LDL-cholesterol. More than a quarter (25.91%) were diagnosed with obesity. 11.37% of the patients with high LDL-cholesterol levels had various metabolic disorders including primary dyslipidemia. A small number of patients with hypercholesterolemia had thyroid disorders (4.10%). Patients with high LDL-cholesterol had various diagnoses ranging from metabolic to neurologic disorders, keeping in mind that there are multiple pathologies that can lead to dyslipidemia. Evaluating children for dyslipidemia is at hand for medical professionals. Screening for dyslipidemia in children would provide the opportunity to prevent rather than treat cardiovascular events.

Aging under endocrine hormone regulation

Aging is a biological process in which the environment interacts with the body to cause a progressive decline in effective physiological function. Aging in the human body can lead to a dysfunction of the vital organ systems, resulting in the onset of age-related diseases, such as neurodegenerative and cardiovascular diseases, which can seriously affect an individual's quality of life. The endocrine system acts on specific targets through hormones and related major functional factors in its pathways, which play biological roles in coordinating cellular interactions, metabolism, growth, and aging. Aging is the result of a combination of many pathological, physiological, and psychological processes, among which the endocrine system can achieve a bidirectional effect on the aging process by regulating the hormone levels in the body. In this paper, we explored the mechanisms of growth hormone, thyroid hormone, and estrogen in the aging process to provide a reference for the exploration of endocrine mechanisms related to aging.

Association Between Thyroid-Stimulating Hormone Level and Bell's Palsy

OBJECTIVE

To investigate whether dysregulated thyroid hormone function is associated with Bell's palsy.

STUDY DESIGN

Cross-sectional.

SETTING

Electronic medical record database of Clalit Health Services (CHS). CHS is an Israeli payer-provider, integrated health care system, serving >4.5 million members (54% of the Israeli population).

PATIENTS

Older than 18 years with Bell's palsy, during 2002 to 2019.

INTERVENTIONS

None.

METHODS

A total of 1,374 patients with Bell's palsy who had thyroid-stimulating hormone (TSH) blood levels measured up to 60 days before the palsy were matched (1:2) for age and sex with 2,748 controls who had TSH blood levels and no history of Bell's palsy.

RESULTS

Retrospective review of the CHS database, from 2002 to 2019 yielded 11,268 patients with Bell's palsy, of which, 1,374 met the inclusion criteria. Mean age was 57.9 years, and 61.4% were female. A higher percentage of patients in the Bell's palsy group had low TSH (≤0.55 mIU/L) compared with controls (5.7% vs. 3.6%, p < 0.001). Low TSH compared with TSH > 0.55 mIU/L, was independently associated with 1.45-fold increased odds for having Bell's palsy (95% CI 1.11-2.02, p < 0.001), when controlled for age, sex, body mass index, diabetes, hypertension, prior cerebrovascular accident, hemoglobin level, and purchasing thyroid hormone drugs. Among the patients with TSH ≤ 0.55 mIU/L, 95.5% had normal free thyroxin and 97.7% had normal free triiodothyronine levels (subclinical hyperthyroidism). For 47.1% of patients, TSH remained ≤0.55 mIU/L, 3 to 12 months after the Bell's palsy occurred and most patients had normal free thyroxin (95.4%) and normal free triiodothyronine (91.8%).

CONCLUSIONS

Subclinical hyperthyroidism is independently associated with Bell's palsy after controlling for multiple confounding factors.

Thyroid dysfunction in young, first-episode and drug-naïve patients with major depressive disorder: prevalence and associated clinical factors

Objective

The incidence of thyroid dysfunction (TD) and major depressive disorder (MDD) is increasing year by year in the general population. However, the prevalence and correlates of TD in first-episode drug-naive (FEDN) MDD patients have not been explored. This study sought to fill this gap and examine the association between TD and MDD.

Methods

We recruited 1,289 FEDN MDD patients aged 18 ~ 45 years. A total of 1,289 FEDN MDD outpatients were recruited. Demographical and suicide data were collected for each patient, and lipid profiles, thyroid function, and fasting blood glucose (FBG) levels were measured. The Hamilton Depression Scale 17 (HAMD-17) was assessed for depression.

Results

The prevalence of TD in young FEDN MDD patients was 64.86%. Compared with those without TD, patients with TD had longer duration of illness, greater HAMD score, higher BMI, TG, TC, and LDL-C levels, and higher suicide attempt rates, but lower HDL-C and FBG levels. Further logistic regression indicated that duration of illness, HAMD score, TC, HDL-C, BMI, and FBG levels were significantly associated with TD.

Limitations

No causal relationship can be drawn due to the cross-sectional design.

Conclusion

TD is common in young FEDN MDD patients. So clinicians should monitor thyroid function in patients with MDD.

Advanced glycation end products and their soluble receptor (sRAGE) in patients with Hashimoto's thyroiditis on levothyroxine substitution

Background

Advanced glycation end products (AGEs) are heterogenous group of irreversible chemical moieties originated from non-enzymatic glycation and oxidation of proteins, nucleic acids, and lipids. The engagement of AGEs with their chief cellular receptor (RAGE) activates a myriad of signaling pathways contributing to the progression of chronic diseases like autoimmune thyroiditis, type 2 diabetes mellitus and its complications. Soluble RAGE (sRAGE) prevents AGE-RAGE interaction in a competitive manner.

Objective

We investigated the association between serum AGE, sRAGE and thyroid function in 73 Hashimoto thyroiditis patients (HT) on levothyroxine substitution, and in 83 age, BMI and gender-matched healthy controls.

Methods

The serum AGEs levels were determined by autofluorescence on a multi-mode microplate reader, and the serum sRAGE levels by ELISA method.

Results

Mean AGE level was lower (10.71 vs 11.45 AU/µg protein; p=0.046), while mean sRAGE level was higher (923 vs 755 pg/mL; p<0.0005) in the serum of HT patients than the controls. AGE correlated with age, while sRAGE correlated negatively with BMI in both groups. We found negative correlation between AGE and fT3 levels (r=-0.32; p=0.006) and sRAGE and TSH levels (r=-0.27; p=0.022) in HT patients, while we failed to find association between AGE, sRAGE and parameters of thyroid function in the control group. Median AGE/sRAGE ratio was lower in HT patients than in controls (2.4, IQR 1.9 - 3.1 vs 3.3, IQR 2.3 - 4.1 AU/pg; p < 0.001). In HT patients, the AGE/sRAGE ratio correlated positively with BMI and correlated negatively with fT3.

Conclusion

According to our results in HT patients lower TSH and higher fT3 levels within the reference range is accompanied by a favorable AGE/RAGE balance. Further investigations are needed to confirm these results.

Early warning signs of thyroid autoantibodies seroconversion: A retrospective cohort study

BACKGROUND

Serum anti-thyroid peroxidase antibody (anti-TPO) and anti-thyroglobulin antibody (anti-Tg) levels are key indicators for the diagnosis of autoimmune diseases, especially autoimmune thyroiditis. Before the thyroid autoantibodies turn from negative to positive, it is unknown whether any clinical indicators in the body play a warning role.

PURPOSE

To establish an early prediction model of seroconversion to positive thyroid autoantibodies.

METHODS

This retrospective cohort study collected information based on clinical laboratory data. A logistic regression model was used to analyse the risk factors associated with a change in thyroid autoantibodies to an abnormal status. A machine-learning approach was employed to establish an early warning model, and a nomogram was used for model performance assessment and visualisation. Receiver operating characteristic (ROC) curves, calibration curves, and decision curve analyses were used for internal and external validation.

RESULTS

Logistic regression analysis revealed that albumin to globulin ratio, triglyceride levels, and Glutamic acid levels among liver function and some metabolism-related indicators, high density lipoprotein C among metabolism-related indicators, and cystatin C among renal function indicators were all risk factors for thyroid antibody conversion (P<0.05). In addition, several indicators in the blood count correlated with thyroid conversion (P<0.05). Changes in the ratio of free thyroxine to free triiodothyronine were a risk factor for positive thyroid antibody conversion (OR_fT4/fT3=1.763; 95% confidence interval 1.554-2.000). The area under the curve (AUC) of the early warning model based on the positive impact of clinical laboratory indicators, age, and sex was 0.85, which was validated by both internal (AUC 0.8515) and external (AUC 0.8378) validation.

CONCLUSIONS

The early warning model of anti-TPO and anti-Tg conversion combined with some clinical laboratory indicators in routine physical examination has a stable warning efficiency.

Hepatic Energy Metabolism under the Local Control of the Thyroid Hormone System

The energy homeostasis of the organism is orchestrated by a complex interplay of energy substrate shuttling, breakdown, storage, and distribution. Many of these processes are interconnected via the liver. Thyroid hormones (TH) are well known to provide signals for the regulation of energy homeostasis through direct gene regulation via their nuclear receptors acting as transcription factors. In this comprehensive review, we summarize the effects of nutritional intervention like fasting and diets on the TH system. In parallel, we detail direct effects of TH in liver metabolic pathways with regards to glucose, lipid, and cholesterol metabolism. This overview on hepatic effects of TH provides the basis for understanding the complex regulatory network and its translational potential with regards to currently discussed treatment options of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) involving TH mimetics.

Type 1 Diabetes Mellitus and Autoimmune Diseases: A Critical Review of the Association and the Application of Personalized Medicine

Type 1 Diabetes Mellitus (T1DM) is a common hyperglycemic disease characterized by the autoimmune destruction of insulin-producing beta cells of the pancreas. Various attempts have been made to understand the complex interplay of genetic and environmental factors which lead to the development of the autoimmune response in an individual. T1DM is frequently associated with other autoimmune illnesses, the most common being autoimmune thyroid disorders affecting more than 90% of people with T1D and autoimmune disorders. Antithyroid antibodies are present in around 20% of children with T1D at the start of the illness and are more frequent in girls. Patients with T1DM often have various other co-existing multi-system autoimmune disorders including but not limited to thyroid diseases, parathyroid diseases, celiac disease, vitiligo, gastritis, skin diseases, and rheumatic diseases. It is a consistent observation in clinics that T1DM patients have other autoimmune disorders which in turn affect their prognosis. Concomitant autoimmune illness might affect diabetes care and manifest itself clinically in a variety of ways. A thorough understanding of the complex pathogenesis of this modern-day epidemic and its association with other autoimmune disorders has been attempted in this review in order to delineate the measures to prevent the development of these conditions and limit the morbidity of the afflicted individuals as well. The measures including antibody screening in susceptible individuals, early identification and management of other autoimmune disorders, and adoption of personalized medicine can significantly enhance the quality of life of these patients. Personalized medicine has recently gained favor in the scientific, medical, and public domains, and is frequently heralded as the future paradigm of healthcare delivery. With the evolution of the ‘omics’, the individualization of therapy is not only closer to reality but also the need of the hour.

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

An imbalance between pro-oxidative and antioxidative cellular mechanisms is oxidative stress (OxS) which may be systemic or organ-specific. Although OxS is a consequence of normal body and organ physiology, severely impaired oxidative homeostasis results in DNA hydroxylation, protein denaturation, lipid peroxidation, and apoptosis, ultimately compromising cells' function and viability. The thyroid gland is an organ that exhibits both oxidative and antioxidative processes. In terms of OxS severity, the thyroid gland's response could be physiological (i.e. hormone production and secretion) or pathological (i.e. development of diseases, such as goitre, thyroid cancer, or thyroiditis). Protective nutritional antioxidants may benefit defensive antioxidative systems in resolving pro-oxidative dominance and redox imbalance, preventing or delaying chronic thyroid diseases. This review provides information on nutritional antioxidants and their protective roles against impaired redox homeostasis in various thyroid pathologies. We also review novel findings related to the connection between the thyroid gland and gut microbiome and analyze the effects of probiotics with antioxidant properties on thyroid diseases.

A comparative study on the Antihyperlipidemic and antibacterial potency of the shoot and flower extracts of Melastoma malabathricum Linn's

Background

Atherosclerosis is arteries’ thickening and stiffening condition manifested due to plaque formation by oxidized-LDL of abundant and deranged lipid metabolism. Traditionally, Melastoma malabathricum Linn (MM) leaves are used for anti-diabetics, abdominal problems, and high blood pressure. The current experiment unveils the potency of ethanol, acetone, and water MM extracts as antibacterial agents and alternative medicine during hyperlipidemic conditions.

Methods

A high cholesterol diet (HCD-2500 mg/kg) was provided with regular feeds for 3 weeks to induce hyperlipidemic mice. Afterward, comparing weight with Group-A (normal control), the hyperlipidemic mice were classified into five groups: Group-B (hyperlipidemic control), Group-C (MFA-500 mg/kg), Group-D (MSE-250 mg/kg), Group-E (MSE-500 mg/kg), and Group-F (ATOVAT-20 mg/kg). And the dosages were given orally for 28 days according to their body weight. Fasting blood was collected at the end of treatment, and serum was taken to test lipid profiling and liver enzymes.

Results

The body mass had waxed significantly (P < 0.001) in all the groups compared with Group-A. Subsequently, orally administered different doses where group-D and group-E demonstrated magnificent anti-hyperlipidemic potency (P < 0.001) compared with group-B. During treatment, rapid upward body mass was tardy in group-E (P < 0.001). However, the liver enzyme expression such as AST, ALT, and ALP was elevated (P < 0.001) in Group-F, they were significantly lessened (P < 0.001, P < 0.01) in Groups-C, D, and E, which indicates these extracts have significant anti-liver damaging potency. Alongside the antibacterial activity of MSE-1500 μg/disc, it exhibited the greatest (16.50 mm) zone of inhibition against Shigella dysenteriae.

Conclusion

However, in our current experiment, depending on the derived data, we can elicit that the Melastoma malabathricum shoot ethanolic (MSE) extract is a potential resource for developing alternative medicine to manage the hyperlipidemic condition.

Evaluation of the Paradoxical Association Between Lipid Levels and Incident Atrial Fibrillation According to Statin Usage: A Nationwide Cohort Study

Objective

Higher levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) are associated with a lower risk of atrial fibrillation (AF). Statin use might exert confounding effects on the paradoxical associations; however, the relationships that distinguish statin users from non-users have not been thoroughly evaluated.

Methods

From the Korean National Health Insurance Database, we included 9,778,014 adults who underwent a health examination in 2009. The levels of TC and LDL-C at the health examination were categorized into quartile values of the total study population. We grouped the study population into statin users and non-users and investigated the associations between TC, LDL-C, and the risk of incident AF.

Results

Of the total population, 867,336 (8.9%) were taking statins. During a mean follow-up of 8.2 years, inverse associations of TC - AF and LDL-C - AF were observed; higher levels of TC and LDL-C were associated with the lower risk of AF in the total population. Overall, statin users showed higher AF incidence rate than non-users, but the inverse associations of TC - AF and LDL-C - AF were consistently observed irrespective of statin usage; adjusted hazard ratio with 95% confidence interval was 0.81 (0.79-0.84) for statin users and 0.81 (0.80-0.83) for non-users in the highest TC quartile, and 0.84 (0.82-0.87) for statin users and 0.85 (0.84-0.86) for non-users in the highest LDL-C quartile (all p<0.001).

Conclusion

The paradoxical relationship between lipid levels (TC and LDL-C) and the risk of AF remains consistent in both statin users and non-users.

PARAMETERS OF CENTRAL AND INTRACARDIAC HAEMODYNAMICS IN WOMEN WITH THYROID HYPERPLASIA AND ACALCULOUS CHOLECYSTITIS

OBJECTIVE

Aim: The study aimed to investigate some parameters of functional status of central and intracardiac haemodynamics in women with thyroid hyperplasia and acalculous cholecystitis.

PATIENTS AND METHODS

Materials and Methods: Functional changes of haemodynamic status in women with thyroid hyperplasia and acalculous cholecystitis were investigated. All data are obtained through general and special clinical methods, standard and special laboratory methods of examination, physiological, biochemical and statistical methods. Parameters of central and intracardiac haemodynamics have been recorded by the method of two-dimensional M-mode echocardiography in the echo chamber "Toshiba-140" (Japan) at the resting state.

RESULTS

Results: An increase in heart rate (by 45.6%) was observed in patients, which led to decreased duration of cardiac cycle and ejection time. Statistically significant (p<0.05, 11.7% on average) increase in total peripheral vascular resistance was indicated. Dynamics of changes of parameters of central and intracardiac haemodynamics indicates different parallel existing pathways of secondary disturbances in the part of cardiovascular system. A significant increase in peripheral vascular resistance associated with decreased elasticity (increased vascular rigidity) of the arteries is the element of concentric type of left ventricular hypertrophy. The increase in volume in the absence of vasospastic reactions and increasing venous tone is an element of eccentric hypertrophy.

CONCLUSION

Conclusions: It is possible to talk about the presence of systolic dysfunction in patients, which, however, is predominantly of functional character. The revealed specific changes in homeostatic haemodynamic characteristics in the women's body with thyroid hyperplasia and acalculous cholecystitis require the development of new, more effective and preferably drug-free (due to liver pathology and detoxification dysfunction) approaches to medical treatment of such patients.

Dyslipidemia Is a Risk Factor for Hypothyroidism in Women: A Longitudinal Cohort Study from South Korea

Background: Hypothyroidism is a risk factor for dyslipidemia. We explored whether dyslipidemia is a risk factor for hypothyroidism. Methods: We performed a retrospective analysis of data from a longitudinal cohort study of South Korean adults who underwent medical examination and ≥4 biochemical assessments of thyroid function. The primary outcome was hypothyroidism (thyrotropin [TSH] >4.2 mU/L), and the secondary outcome was severe subclinical hypothyroidism (SCH; TSH ≥10.0 mU/L and normal free thyroxine [fT4] level) or overt hypothyroidism (OH; total triiodothyronine <80 ng/dL and/or fT4 < 0.93 ng/dL and high TSH values). The association of baseline dyslipidemia status with subsequent hypothyroidism was evaluated using Kaplan-Meier curves with the log-rank test and Cox proportional hazards regression models (for the entire population and respective genders). Subgroup analyses according to age (<40 and ≥40 years) and body-mass index (BMI; <23, 23-25, and ≥25 kg/m²) were performed according to gender. Results: We included 1665 participants. During a median follow-up period of 61.0 months, 24.3% (404/1665) individuals developed hypothyroidism. Among these, 36 participants (2.1%) had severe SCH or OH. Excluding patients with a first abnormal TSH level at last follow-up, 44.5% (126/283) of the patients with hypothyroidism had spontaneous TSH normalization. In respective multivariate analyses, dyslipidemia at baseline was independently associated with development of hypothyroidism in women (adjusted hazard ratio [HR] = 2.05 [1.31-3.19], p = 0.002), but not in men (adjusted HR = 1.00 [0.77-1.30], p = 0.991). In women, the presence of dyslipidemia at baseline was associated with development of severe SCH or OH (adjusted HR = 5.33 [1.41-20.12], p = 0.014). In women, respective associations according to age and BMI were as follows: age <40 years, adjusted HR = 2.90 (1.34-6.26, p = 0.007); age ≥40 years, adjusted HR = 1.85 (1.08-3.14, p = 0.023); BMI <23 kg/m², adjusted HR = 1.68 (0.82-3.43, p = 0.151); BMI = 23-25 kg/m², adjusted HR = 2.17 (0.93-5.07, p = 0.071); and BMI ≥25 kg/m², adjusted HR = 2.82 (1.16-6.86, p = 0.022). Conclusions: In Korean adults, dyslipidemia was associated with development of hypothyroidism in women. Our findings require confirmation.

Brown adipose tissue influences adiponectin and thyroid hormone changes during Graves' disease therapy

Thyroid hormones (TH), adiponectin and brown adipose tissue (BAT) are regulators of energy homoeostasis. Influence of BAT activity on the relationship between TH and adiponectin remains unexplored. The aim of the study was to identify the relationship between TH and adiponectin and to clarify the impact of active BAT on the metabolic effects of adiponectin before and after the correction of thyrotoxicosis. Twenty-one patients with newly diagnosed hyperthyroidism from Graves' disease were recruited. A titration dosing regimen of thionamide anti-thyroid drug (ATD) was used to establish euthyroidism over 12-24 weeks. Anthropometric, biochemical and adipocytokine parameters were measured before and after control of hyperthyroidism. BAT activity was quantified by fusion 18 F-fluorodeoxyglucose (18 F-FDG) PET/MR imaging, and patients were grouped based on BAT status. Plasma adiponectin level was significantly increased following correction of hyperthyroidism in the overall sample. Free thyroxine (FT4) was also identified as a predictor of adiponectin level in thyroid dysfunction. However, significant changes in adiponectin level and correlations involving adiponectin were absent in BAT-positive patients but maintained in BAT-negative patients. BAT activity diminishes the correlative relationship with body composition and abolishes TH and adiponectin relationships when transitioning from a hyperthyroid to euthyroid state.

Educational and research needs in hypothyroidism of primary care physicians in the Community of Madrid

AIM

To document the opinion of primary care physicians on hypothyroidism and explore their educational and research needs.

METHODS

A web-based survey was released through Healthcare Management offices in Madrid to be answered anonymously by the doctors at the health centers.

RESULTS

Five hundred and forty-six out of 3897 (14%) physicians completed the survey. More than 90% of respondents agreed that hypothyroidism is a common and easily managed health problem and that its poor control increases healthcare costs. This percentage was higher in older doctors and those with longer professional experience. 88.1% of respondents showed interest in educational activities (86.6% in receiving and 20.9% in providing education). The preference for clinical sessions in the health center (71.5%) exceeded that of sessions in the hospital (20.2%), while the preference for online courses (67.8%) exceeded that of face-to-face courses (50.9%). 53.5% of interviewees expressed interest in research on hypothyroidism. Women and professionals with a higher number of hypothyroid patients under their care were more likely to be interested in educational and research activities.

CONCLUSION

Primary care physicians in the Community of Madrid are aware of the health problem posed by thyroid hormone deficiency and are clearly in favour of participating in educational and research activities in this area of knowledge.

Important Hormones Regulating Lipid Metabolism

There is a wide variety of kinds of lipids, and complex structures which determine the diversity and complexity of their functions. With the basic characteristic of water insolubility, lipid molecules are independent of the genetic information composed by genes to proteins, which determine the particularity of lipids in the human body, with water as the basic environment and genes to proteins as the genetic system. In this review, we have summarized the current landscape on hormone regulation of lipid metabolism. After the well-studied PI3K-AKT pathway, insulin affects fat synthesis by controlling the activity and production of various transcription factors. New mechanisms of thyroid hormone regulation are discussed, receptor α and β may mediate different procedures, the effect of thyroid hormone on mitochondria provides a new insight for hormones regulating lipid metabolism. Physiological concentration of adrenaline induces the expression of extrapituitary prolactin in adipose tissue macrophages, which promotes fat weight loss. Manipulation of hormonal action has the potential to offer a new therapeutic horizon for the global burden of obesity and its associated complications such as morbidity and mortality.

Association between Thyroid Hormones and Non-alcoholic Fatty Liver Disease and Non-alcoholic Steatohepatitis in Obese Individuals Undergoing Bariatric Surgery

Background: Non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and hepatic fibrosis have emerged as one of the leading causes of chronic liver disease. The prevalence of the NAFLD spectrum has increased, which can be attributed to the rise in obesity. As NAFLD can ultimately lead to liver cirrhosis, it is imperative to identify modifiable risk factors associated with its onset and progression to provide timely intervention to prevent potentially disastrous consequences. Considering the pivotal role of the endocrine axis in several metabolic pathways such as obesity and insulin resistance, thyroid hormones are crucial in the pathophysiology of NAFLD. The study is focused on the identification of an association between thyroid function and radiographic and histological parameters of NAFLD in patients with severe obesity. Methods: Ninety patients were recruited for this study and underwent initial assessments, including demographic profiles, anthropometric measurements, hepatic biopsy, and basic laboratory tests. Liver stiffness was evaluated using two-dimensional shear wave elastography (2D-SWE) at least 2 weeks before liver biopsy. Results: Among the 90 participants, 80% were women. The mean age was 38.5±11.1 years, and the mean body mass index (BMI) was 45.46±6.26 kg/m2. The mean levels of serum T3 and free T4 in patients with positive histology were not statistically significant compared with patients with negative histology. Furthermore, there was no statistical significance in the mean T3 and free T4 levels between patients diagnosed with hepatic steatosis or fibrosis (on ultrasonography and elastography) and those with negative hepatic imaging. Serum levels of thyroid-stimulating hormone (TSH) were negatively correlated with ultrasonography (P=0.007). Binary logistic regression analysis revealed that none of the thyroid hormones was a predictive factor for liver histology in both adjusted and crude models. Conclusion: The results from our analysis did not suggest an association between thyroid hormones and NAFLD, which is in line with several previously published studies. However, the authors note that there are published data that do propose a link between the two entities. Therefore, well-designed large-scale clinical studies are required to clarify this discrepancy.

Thyroid hormones as a disease modifier and therapeutic target in nonalcoholic steatohepatitis

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide and closely interconnected to the metabolic syndrome. Liver-specific and systemic signaling pathways orchestrating glucose and fatty acid metabolism contribute to intrahepatic accumulation of lipids and inflammatory processes eventually causing disease progression to nonalcoholic steatohepatitis (NASH), liver fibrosis, and cirrhosis. Since a high number of key regulatory genes regarding liver homeostasis are directly mediated via thyroid hormone (TH) signaling, targeting TH receptors (TRs) represent a promising therapeutic potential for the treatment of NAFLD.

AREAS COVERED

In this review, we elucidate the effects of TH on metabolic regulations in the liver via local availability and actions. We discuss recent advances and the potential impact of thyromimetics in basic research and clinical trials including liver-targeted and TRβ-specific agents for the treatment of NAFLD.

EXPERT OPINION

Unselective TR targeting can be accompanied by negative side effects due to high TRβ expression in other organs and TRα-mediated effects. Recent advances in drug development and the introduction of liver-targeted thyromimetics selectively activating TRβ such as Resmetirom (MGL-3196) and VK2809 bring new hope of translating the knowledge on local TH effects into effective hepatic lipid-clearing therapies against NASH.

Investigation of the effect of boron on thyroid functions and biochemical parameters in hypothyroid induced-rats

In the study investigating the effects of boron on thyroid hormones and some biochemical parameters in hypothyroid rats, 49 Wistar Albino male rats were divided into seven groups; (Control (C), Hypothyroidism (H), boron groups (B10, and B20), hypothyroid + boron groups (HB10 and HB20), and Treatment (T). Four groups (H, HB10, HB20, and T) were administered 10 mg/kg (B10 and HB10), 20 mg/kg (B20 and HB20) boron for 3 weeks, respectively after hypothyroidism was induced using Propycil® containing propylthiouracil (PTU). Thyroid hormone analyses and biochemical measurements were made from the serum and thyroid gland tissue was examined histopathologically. According to the findings, the fT3 level increased in the B10 group compared to the control group (p < 0.05). While AST, ALT, and ALP activities were found to be higher in the hypothyroid group than in the control group, AST and ALP activities in the HB10 and HB20 groups decreased to values close to the control group. Total cholesterol levels were found to be lower in boron-given groups compared to control and hypothyroid groups (p < 0.05). Sodium iodide symporter (NIS) immunoreactivity was found to be high in hypothyroid rat groups. As a result, it was observed that the increased AST and ALP activities in rats decreased with boron administration. The serum hormone levels measured in the study are not sufficient to understand the effect of boron on the thyroid gland, and it was concluded that further studies at the molecular level are needed to understand the effects of boron on the thyroid gland.

Update on subclinical thyroid dysfunction

Subclinical thyroid dysfunction is defined by serum thyroid-stimulating hormone (TSH) levels either greater or less than the reference range with normal thyroxine (T4) concentrations, and consists of subclinical hypothyroidism (SCH) and subclinical hyperthyroidism (SCHyper). For the proper diagnosis of SCH, it is most important to be able to correctly evaluate the serum TSH levels, which have numerous unique characteristics. We also need to be versed in TSH harmonization, which was recently launched world-wide. In this review, we will attempt to determine the best clinical approaches to the treatment of subclinical thyroid dysfunction based on recent guidelines published from several countries and novel findings of several recent large-scale clinical studies.

Influence of Altered Thyroid Hormone Mechanisms in the Progression of Metabolic Dysfunction Associated with Fatty Liver Disease (MAFLD): A Systematic Review

We performed a systematic review of the mechanisms of thyroid hormones (THs) associated with metabolic dysfunction associated with fatty liver disease (MAFLD). This systematic review was registered under PROSPERO (CRD42022323766). We searched the MEDLINE (via PubMed) and Embase databases from their inception to March 2022. We included studies that assessed thyroid function by measuring the serum level of THs and those involved in MAFLD. We excluded reviews, case reports, editorials, letters, duplicate studies and designed controls. Forty-three studies included MAFLD, eleven analyzed THs, and thirty-two evaluated the mechanisms of THs in MAFLD. Thyroid hormones are essential for healthy growth, development and tissue maintenance. In the liver, THs directly influence the regulation of lipid and carbohydrate metabolism, restoring the homeostatic state of the body. The selected studies showed an association of reduced levels of THs with the development and progression of MAFLD. In parallel, reduced levels of T3 have a negative impact on the activation of co-regulators in the liver, reducing the transcription of genes important in hepatic metabolism. Overall, this is the first review that systematically synthesizes studies focused on the mechanism of THs in the development and progression of MAFLD. The data generated in this systematic review strengthen knowledge of the impact of TH changes on the liver and direct new studies focusing on therapies that use these mechanisms.

Mediation effects of thyroid function in the associations between phthalate exposure and lipid metabolism in adults

Phthalates are a group of industrial chemicals widely used in everyday products including cosmetics, food packaging and containers, plastics, and building materials. Previous studies have indicated that urinary phthalate metabolites are associated with metabolic effects including those on lipid metabolism, but the results are mixed. Furthermore, whether thyroid function mediates the association between phthalate exposure and lipid metabolism remains unclear. In the present study, we explored whether changes in thyroid function markers mediate the associations between phthalate exposure and lipid metabolism indicators in Taiwanese adults. The cross-sectional data were obtained from the Taiwan Environmental Survey for Toxicants conducted in 2013. Levels of 11 urinary phthalate metabolites, levels of 5 thyroid hormones, and 8 indicators of lipid metabolism were assessed in 222 Taiwanese adults. The relationships of urinary phthalate metabolite levels with serum thyroid hormone levels and lipid metabolism indicators were explored using multiple regression models. Mediation analysis was conducted to evaluate the role of thyroid function in the association between phthalate exposure and lipid metabolism. The metabolite of di(- 2-ethylhexyl) phthalate (∑DEHPm) exhibited a significant positive association with the lipid metabolite indicator of high-density lipoprotein cholesterol (HDL-C; β = 0.059, 95% confidence interval [CI] = 0.009, 0.109) in adults, and the thyroid function indicator thyroxine (T₄) had a significant negative association with the metabolite ∑DEHPm (β = - 0.059, 95% CI = - 0.101, - 0.016) and a significant negative association with HDL-C (β = - 0.284, 95% CI = - 0.440, - 0.128). The T₄ indirect effect was 0.015 (95% CI = - 0.0087, 0.05), and the mediation effect was 32.2%. Our results support the assumption that exposure to phthalates influences the homeostasis of lipid metabolism by interfering with thyroid function.

Clinical Aspects of Genetic and Non-Genetic Cardiovascular Risk Factors in Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is the most common monogenic metabolic disorder characterized by considerably elevated low-density lipoprotein cholesterol (LDL-C) levels leading to enhanced atherogenesis, early cardiovascular disease (CVD), and premature death. However, the wide phenotypic heterogeneity in FH makes the cardiovascular risk prediction challenging in clinical practice to determine optimal therapeutic strategy. Beyond the lifetime LDL-C vascular accumulation, other genetic and non-genetic risk factors might exacerbate CVD development. Besides the most frequent variants of three genes (LDL-R, APOB, and PCSK9) in some proband variants of other genes implicated in lipid metabolism and atherogenesis are responsible for FH phenotype. Furthermore, non-genetic factors, including traditional cardiovascular risk factors, metabolic and endocrine disorders might also worsen risk profile. Although some were extensively studied previously, others, such as common endocrine disorders including thyroid disorders or polycystic ovary syndrome are not widely evaluated in FH. In this review, we summarize the most important genetic and non-genetic factors that might affect the risk prediction and therapeutic strategy in FH through the eyes of clinicians focusing on disorders that might not be in the center of FH research. The review highlights the complexity of FH care and the need of an interdisciplinary attitude to find the best therapeutic approach in FH patients.

Arterial Stiffness in Thyroid and Parathyroid Disease: A Review of Clinical Studies

Growing evidence shows that arterial stiffness measurement provides important prognostic information and improves clinical stratification of cardiovascular risk. Thyroid and parathyroid diseases are endocrine diseases with a relevant cardiovascular burden. The objective of this review was to consider the relationship between arterial stiffness and thyroid and parathyroid diseases in human clinical studies. We performed a systematic literature review of articles published in PubMed/MEDLINE from inception to December 2021, restricted to English languages and to human adults. We selected relevant articles about the relationship between arterial stiffness and thyroid and parathyroid diseases. For each selected article, data on arterial stiffness were extracted and factors that may have an impact on arterial stiffness were identified. We considered 24 papers concerning hypothyroidism, 9 hyperthyroidism and 16 primary hyperparathyroidism and hypoparathyroidism. Most studies evidenced an increase in arterial stiffness biomarkers in hypothyroidism, hyperthyroidism and primary hyperparathyroidism, even in subclinical and mild forms, although heterogeneity of measurement methods and of study designs prevented a definitive conclusion, suggesting that the assessment of arterial stiffness may be considered in the clinical evaluation of cardiovascular risk in these diseases.