Thyroid hormones regulate both cardiovascular and renal mechanisms underlying hypertension

Genetic Factors Related to the Development or Progression of Mesoamerican Endemic Nephropathy

Over the past two decades, Mesoamerican endemic nephropathy (MeN) has become a major public health problem in certain regions of Mexico and Central American countries. The etiology of this disease is multifactorial, and important environmental factors have been described, such as chronic heat stress, recurrent episodes of dehydration, infections, and exposure to toxins of chemical and biological origin. Genetic and epigenetic factors have been proposed to play significant roles in MeN. Recent studies have analyzed the role of these factors in MeN. In some cases, these factors appear to be associated with accelerated deterioration of established kidney disease due to preexisting endothelial dysfunction and tubulopathy. In other cases, they appear to be associated with early kidney damage, even before occupational exposure, suggesting that they may play a relevant role in the genesis of the disease. Other factors appear to act as risk reducers for developing MeN in areas with a high prevalence of the disease. Therefore, this disease has a rather complex multifactorial etiology, with possible polygenic contributions, possible epigenetic phenomena, and multiple environmental factors.

Potential therapeutic impacts of vitamin D on hypothyroid-induced heart and kidney fibrosis and oxidative status in male rat

There are several interactions between thyroid hormones (THs) and kidney and heart function. Consequently, THs deficit results in profound changes in renal and cardiac function regulation. Interestingly, emerging evidence suggests that vitamin D (Vit D) may benefit to fibrotic lesions in various tissues. Herein, this study was designed to investigate the potential impact of Vit D on renal and cardiac fibrosis in hypothyroid rats. Forty male Wistar rats were divided into four groups as follow: control, hypothyroid (0.05% PTU in drinking water), and hypothyroid + Vit D (PTU and doses of 100 or 500 IU/kg/day, by gavage) groups. After 6 weeks, biochemical parameters such as creatinine and urea in serum samples, and oxidative stress markers including malondialdehyde (MDA), total thiol groups, and superoxide dismutase (SOD) in renal and cardiac tissues homogenate were measured. Also, renal and cardiac fibrosis was evaluated histologically using Masson's trichrome staining. Hypothyroidism significantly increased creatinine and urea. Also, in hypothyroid group renal and cardiac fibrosis as well as MDA were increased, while anti-oxidative markers including total thiol group and SOD were decreased. Administration of Vit D significantly improved these alterations in oxidative stress markers and fibrosis in renal and cardiac tissues. In conclusion, this study highlighted that Vit D supplementation reduced renal and cardiac fibrosis and improved oxidative stress. These results support the emerging experimental findings linking Vit D being introduced as a potential therapeutic agent.

Low maternal iodine intake and subsequent risk of pharmacologically treated hypertension: A population-based prospective cohort study

BACKGROUND & AIMS

Iodine deficiency is linked to multiple adverse health outcomes, but there is scarce knowledge regarding iodine intake and development of chronic hypertension. We aimed to investigate the prospective association between habitual dietary iodine intake and pharmacologically treated hypertension in mothers up to 10 years after delivery.

METHODS

The present study is based on data from an ongoing pregnancy cohort and includes 58,629 women without thyroid dysfunction and hypertension at baseline. The study outcome was new-onset hypertension defined according to antihypertensive medication use initiated 90 days after delivery registered in the national prescription database. We estimated hazard ratios (HR) with 95 % Confidence Intervals (95 % CI) using Cox regression models.

RESULTS

During a median follow-up duration of 7.1 years, a total of 1422 (2.4 %) women developed new-onset hypertension. There was a non-linear association between dietary iodine intake and new-onset hypertension. Women with iodine intakes lower than 100 μg/day had significantly higher risk than those with iodine intakes in the recommended range 150-199 μg/day (adjusted HR, 1.29; 95 % CI: 1.09, 1.53). This was evident in normotensive pregnancies (adjusted HR 1.25; 95 % CI: 1.01, 1.54) and in women with gestational hypertension (adjusted HR 1.35; 95 % CI: 1.00, 1.83). The association between low iodine intake and hypertension remained in all sensitivity analyses considering pre-pregnancy and pregnancy-related factors.

CONCLUSIONS

This study suggests that women with iodine intakes below 100 μg/day have a higher likelihood of new-onset hypertension and adds supporting evidence to the importance of correcting mild-to-moderate iodine deficiency in women of reproductive age.

The Impact of Thyroid Hormone Imbalance on Cardiovascular Health: A Population-Based Study

INTRODUCTION

Thyroid hormone imbalances are known to significantly affect cardiovascular health, contributing to conditions such as arrhythmias, dyslipidemia, and hypertension. Given the increasing prevalence of thyroid dysfunction and its potential impact on cardiovascular outcomes, early diagnosis and intervention are crucial, particularly within specific regional populations.

OBJECTIVE

This study aimed to evaluate the impact of thyroid hormone imbalance on cardiovascular health outcomes in patients at Lady Reading Hospital, Peshawar, over a 24-month period.

MATERIALS AND METHODS

A prospective cohort study was conducted between October 2022 and September 2024, involving 150 adult patients diagnosed with thyroid dysfunction, categorized into subclinical, hyperthyroid, and hypothyroid groups. The study assessed key cardiovascular health indicators, including blood pressure, lipid profiles, heart rate, and electrocardiograms (ECGs), at baseline and during follow-up visits at 6, 12, and 24 months. Participants were included if they met the biochemical criteria for thyroid dysfunction and had no significant pre-existing cardiovascular disease. Data were collected through medical records and standardized questionnaires. The Institutional Review Board at Lady Reading Hospital approved the study.

RESULTS

Dyslipidemia was found in 90 participants (60%), hypertension in 99 participants (66%), and hypothyroidism in 76 participants (72%). Arrhythmias were observed in 14 individuals (46%) with hyperthyroidism. ECG findings revealed sinus bradycardia in 32 participants (30%) with hypothyroidism and sinus tachycardia in 23 participants (76%) with hyperthyroidism. Multivariate analysis showed that hypothyroidism significantly increased the odds of hypertension (OR = 3.2, p = 0.001), dyslipidemia (OR = 2.9, p = 0.003), and arrhythmias (OR = 4.3, p < 0.001).

CONCLUSION

Thyroid hormone imbalance has a profound impact on cardiovascular health, with hyperthyroidism linked to arrhythmias and hypothyroidism associated with hypertension and dyslipidemia. Subclinical thyroid dysfunction also increases cardiovascular risks, emphasizing the need for early detection and region-specific management strategies. This study provides valuable insights into the long-term cardiovascular effects of thyroid dysfunction in the Khyber Pakhtunkhwa (KPK) region, supporting the importance of routine screening and timely intervention.

Low Thyroid Hormones Level Attenuates Mitochondrial Dysfunction and Right Ventricular Failure in Pulmonary Hypertensive Rats

PURPOSE

This study is to investigate the repercussions of hypothyroidism in the pathophysiological progression of pulmonary arterial hypertension (PAH).

METHODS

While the control (CTL, n = 5) male Wistar rats received vehicle, PAH was induced with monocrotaline (MCT group, n = 15). Hypothyroidism was induced in a subset of rats by methimazole 3 weeks prior to the MCT injection (MMZ + MCT group, n = 15). Plasma thyroid hormones were measured by radioimmunoassay. Electrocardiographic, echocardiographic, and hemodynamic analyses were performed to evaluate the progression of PAH. Gene expression of antioxidant enzymes and cardiac hypertrophy markers were assessed by qPCR. Mitochondrial respiration, ATP levels, and ROS production were measured in right ventricular (RV) samples.

RESULTS

Plasma T3 and T4 decreased in both MCT and MMZ + MCT groups (p < 0.05). Right ventricular systolic pressure (RVSP) increased, and RV - dP/dt, + dP/dt, and contractility index decreased in the MCT versus the CTL group and remained within control levels in the MMZ + MCT group (p < 0.05). Relative RV weight, RV wall thickness, RV diastolic area, and relative lung weight were augmented in the MCT versus the CTL group, whereas all parameters were improved to the CTL levels in the MMZ + MCT group (p < 0.05). Only the MCT group exhibited an increased duration of QTc interval compared to the baseline period (p < 0.05). ADP-induced mitochondrial respiration and ATP levels were decreased, and ROS production was increased in MCT versus the CTL group (p < 0.05), while the MMZ + MCT group exhibited increased mitochondrial respiration versus the MCT group (p < 0.05).

CONCLUSION

Hypothyroidism attenuated the RV mitochondrial dysfunction and the pathophysiological progression of MCT-induced PAH.

Natriuretic peptide system in hypertension: Current understandings of its regulation, targeted therapies and future challenges

The natriuretic peptide system (NPS) is the key driving force of the heart's endocrine function. Recent developments in NPS-targeted therapies have been found promising and effective against cardiovascular diseases, including hypertension. Notably, after discovering crosstalk between NPS and the renin-angiotensin-aldosterone system (RAAS), various combinations such as neprilysin/angiotensin II receptor type 1 AT1 receptor inhibitors and neprilysin/renin inhibitors have been preclinically and clinically tested against various cardiac complications. However, the therapeutic effects of such combinations on the pathophysiology of hypertension are poorly understood. Furthermore, the complicated phenomena underlying NPS regulation and function, particularly in hypertension, are still unexplored. Mounting evidence suggests that numerous regulatory mechanisms modulate the expression of NPS, which can be used as potential targets against hypertension and other cardiovascular diseases. Therefore, this review will specifically focus on epigenetic and other regulators of NPS, identifying prospective regulators that might serve as new therapeutic targets for hypertension. More importantly, it will shed light on recent developments in NPS-targeted therapies, such as M-atrial peptides, and their latest combinations with RAAS modulators, such as S086 and sacubitril-aliskiren. These insights will aid in the development of effective therapies to break the vicious cycle of high blood pressure during hypertension, ultimately addressing the expanding global heart failure pandemic.

Evaluation of Neuro-Hormonal Dynamics after the Administration of Probiotic Microbial Strains in a Murine Model of Hyperthyroidism

The microbiota-gut-brain axis has received increasing attention in recent years through its bidirectional communication system, governed by the ability of gut microorganisms to generate and regulate a wide range of neurotransmitters in the host body. In this research, we delve into the intricate area of microbial endocrinology by exploring the dynamic oscillations in neurotransmitter levels within plasma and brain samples. Our experimental model involved inducing hyperthyroidism in mice after a "probiotic load" timeframe using two strains of probiotics (Lactobacillus acidophilus, Saccharomyces boulardii, and their combination). These probiotic interventions continued throughout the experiment and were intended to uncover potential modulatory effects on neurotransmitter levels and discern if certain probiotic strains exhibit any protection from hyperthyroidism. Moreover, we aimed to outline the eventual connections between the gut microbiota and the hypothalamus-pituitary-thyroid axis. As our study reveals, there are significant fluctuations in crucial neurotransmitters within the hyperthyroidism model, related to the specific probiotic strain or combination. These findings could support future therapeutic approaches, help healthcare professionals choose between different probiotic therapies, and also allow us proceed with caution when administering such treatments, depending on the health status of hyperthyroid patients.

The Association Between Thyroid Hormones and Renal Function in Euthyroid Chinese Individuals: A Population-Based Cross-Sectional Study

Objective This population-based cross-sectional study aimed to investigate the association between thyroid hormones and renal function in euthyroid Chinese individuals, as the relationship between thyroid hormones and renal function in this population remains unclear. Methods A total of 661 participants were included in the study after excluding individuals with thyroid diseases, incomplete clinical measurements, or those taking medications affecting thyroid function. Participants were categorized into three groups based on serum thyroid hormone and antibody levels. The study adjusted for covariates and assessed the glomerular filtration rate (GFR) and urine albumin-to-creatinine ratio (ACR) in relation to thyroid hormone levels. Results After adjusting for covariates, the study found a significant increase in GFR in the middle and highest tertiles of free triiodothyronine (FT3) and the highest tertile of total triiodothyronine (TT3). Serum FT3 and TT3 levels were significantly associated with GFR. Additionally, the study observed a significantly lower GFR in the highest tertile of thyroid-stimulating hormone (TSH) compared to the lowest tertile. However, thyroid hormone and antibody levels were not associated with the ACR. Furthermore, the highest tertiles of TT3 and total thyroxine (TT4) were associated with a decreased risk of chronic kidney disease (CKD). Conclusion In our study among euthyroid Chinese individuals, we observed a significant association between thyroid function and GFR. Specifically, lower FT3, TT3, and higher TSH were associated with reduced GFR, indicating a potential role for thyroid hormones in maintaining renal function. Furthermore, lower levels of TT3 and TT4 were associated with an increased risk of CKD. These findings suggest a direct link between thyroid and renal function, even in euthyroid individuals, emphasizing the need for further investigation to elucidate the underlying mechanisms and potential therapeutic implications.

Protein-protein interaction network-based integration of GWAS and functional data for blood pressure regulation analysis

BACKGROUND

It is valuable to analyze the genome-wide association studies (GWAS) data for a complex disease phenotype in the context of the protein-protein interaction (PPI) network, as the related pathophysiology results from the function of interacting polyprotein pathways. The analysis may include the design and curation of a phenotype-specific GWAS meta-database incorporating genotypic and eQTL data linking to PPI and other biological datasets, and the development of systematic workflows for PPI network-based data integration toward protein and pathway prioritization. Here, we pursued this analysis for blood pressure (BP) regulation.

METHODS

The relational scheme of the implemented in Microsoft SQL Server BP-GWAS meta-database enabled the combined storage of: GWAS data and attributes mined from GWAS Catalog and the literature, Ensembl-defined SNP-transcript associations, and GTEx eQTL data. The BP-protein interactome was reconstructed from the PICKLE PPI meta-database, extending the GWAS-deduced network with the shortest paths connecting all GWAS-proteins into one component. The shortest-path intermediates were considered as BP-related. For protein prioritization, we combined a new integrated GWAS-based scoring scheme with two network-based criteria: one considering the protein role in the reconstructed by shortest-path (RbSP) interactome and one novel promoting the common neighbors of GWAS-prioritized proteins. Prioritized proteins were ranked by the number of satisfied criteria.

RESULTS

The meta-database includes 6687 variants linked with 1167 BP-associated protein-coding genes. The GWAS-deduced PPI network includes 1065 proteins, with 672 forming a connected component. The RbSP interactome contains 1443 additional, network-deduced proteins and indicated that essentially all BP-GWAS proteins are at most second neighbors. The prioritized BP-protein set was derived from the union of the most BP-significant by any of the GWAS-based or the network-based criteria. It included 335 proteins, with ~ 2/3 deduced from the BP PPI network extension and 126 prioritized by at least two criteria. ESR1 was the only protein satisfying all three criteria, followed in the top-10 by INSR, PTN11, CDK6, CSK, NOS3, SH2B3, ATP2B1, FES and FINC, satisfying two. Pathway analysis of the RbSP interactome revealed numerous bioprocesses, which are indeed functionally supported as BP-associated, extending our understanding about BP regulation.

CONCLUSIONS

The implemented workflow could be used for other multifactorial diseases.

Renal function changes in patients with subclinical hyperthyroidism: a novel postulated mechanism

BACKGROUND

Subclinical hyperthyroidism (SCH) is found to be associated with renal dysfunction. Hyperthyroidism is a well-known cause of secondary systolic hypertension. However, the effect of SCH on the kidney and its vasculature is still unknown.

AIM

To assess the presence of renal function changes and renal vasodysfunction in SCH patients and their relation to hypertension.

METHODS

The study included 321 patients with SCH and 80 healthy matched controls. Laboratory investigations included thyroid function tests, anti-TSH receptor antibody (TRAb), creatinine, estimated glomerular filtration rate (eGFR), serum osmolarity (S. Osmol), urine osmolarity (U. Osmol), Fractional Excretion of Sodium (FeNa), Fractional Excretion of Potassium (FeK), copeptin (CPP), and aldosterone/renin ratio (ARR). Ultrasound for the thyroid gland, echocardiography, total peripheral resistance (TPR), flow-mediated dilatation (FMD), and Renal Arterial distensibility (RAD) was also done.

RESULTS

Serum creatinine was significantly lower while eGFR was significantly higher in SCH patients compared to euthyroid subjects (mean 0.59 ± 0.11 mg/dl Vs mean 0.8 ± 0.1 mg/dl, p = 0.001 and mean 128.28 ± 14.69 ml/min/1.73m2 Vs mean 100.49 ± 14.9 ml/min/1.73m2, p = 0.013, respectively). The TPR and FMD showed a significant decrease in SCH group compared to controls (mean 975.85 ± 159.33 mmHg.min/L Vs mean 1120.24 ± 135.15 mmHg.min/L, p = 0.045 and mean 7.03 ± 4.02% Vs mean 13.48 ± 4.57%, p = 0.003, respectively). RAD was significantly higher in hypertensive SCH patients compared to normotensive SCH patients (mean 17.82 ± 2.46 mmHg Vs mean 11.98 ± 3.21 mmHg, p = 0.001).

CONCLUSION

SCH patients showed vascular resistance reduction. Alterations in thyroid hormones and blood pressure could be the driving mechanisms for the change in renal functions in patients with SCH.

Minimal change disease with papillary thyroid carcinoma: a report of two adult cases

BACKGROUND

Minimal change disease (MCD), a pathological type of nephrotic syndrome (NS), can occur in patients with tumors. We report two adult cases of MCD associated with papillary thyroid carcinoma (PTC), known to be extremely rare in adults.

CASE PRESENTATION

A 35-year-old female patient was simultaneously diagnosed with MCD and PTC. The MCD was effectively treated with thyroidectomy and prednisone.In addition, a 50-year-old male patient, who had been diagnosed with PTC three years prior, had MCD confirmed by renal biopsy. The patient achieved complete remission following treatment with tacrolimus and rituximab.

CONCLUSIONS

The present case report describes and discusses the diagnostic and treatment processes employed in these two patients. Clinicians need to be aware of the renal effects of treating patients with solid tumors.

Development and Validation of a Prediction Model for 5-Year Risk of Kidney Dysfunction in Patients with Hypertension and Glucose Metabolism Disorder

Purpose

Patients with hypertension and glucose metabolism disorder (GMD) are at high risk of developing kidney dysfunction (KD). Therefore, we aimed to develop a nomogram for predicting individuals’ 5-year risk of KD in hypertensives with GMD.

Patients and Methods

In total, 1961 hypertensives with GMD were consecutively included. Baseline data were extracted from medical electronic system, and follow-up data were obtained using annual health check-ups or hospital readmission. KD was defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73m². Subjects were randomly divided into training and validation sets with a ratio of 7 to 3. Least absolute shrinkage and selection operator method was used to identify potential predictors. Cox proportional hazard model was applied to build a nomogram for predicting KD risk. The discriminative ability, calibration and usefulness of the model were evaluated. The prediction model was verified by internal validation.

Results

During the follow-up of 5351 person-years with a median follow-up of 32 (range: 3–91) months, 130 patients developed KD. Age, sex, ethnicity, hemoglobin A1c, uric acid, and baseline eGFR were identified as significant predictors for incident KD and used for establishing nomogram. The prediction model displayed good discrimination with C-index of 0.770 (95% CI: 0.712–0.828) and 0.763 (95% CI: 0.704–0.823) in training and validation sets, respectively. Calibration curve indicated good agreement between the predicted and actual probabilities. The decision curve analysis demonstrated that the model was clinically useful.

Conclusion

The prediction nomogram, including six common easy-to-obtain factors, shows good performance for predicting 5-year risk of KD in hypertensives with GMD. This quantitative tool could help clinicians, and even primary care providers, recognize potential KD patients early and make strategy for prevention and management.

Biochemical changes in patients during hypothyroid phase after thyroidectomy

Hypothyroidism is the most common long-term consequence after total thyroidectomy. The objective of the present study was to evaluate the lipid profile and liver function in patients after hypothyroidism. Sixty patients who underwent a surgical operation to remove thyroid were included in this study, and thirty healthy subjects were used as a control. The study was conducted at Al-Sadr Medical City in Al-Najaf city, in Iraq, from October 2020 to March 2021. Thyroid-stimulating hormone (TSH) was very high in patients at a hypothyroid stage after hypothyroidism. The results showed a significant increase in total cholesterol, triglycerides (TG), low-density lipoprotein (LDL), and the ratio of total cholesterol/high-density lipoprotein (HDL). The study also revealed a significant increase in the liver enzymes aspartate aminotransferase (AST) and alanine transaminase (ALT) and a significant decrease in alkaline phosphatase (ALP) in patients with thyroidectomy compared to the control group. The correlation matrix revealed a strong positive correlation between TSH levels and total cholesterol, triglycerides, LDL, AST, ALT, and ALP. It was concluded that hypothyroidism, the major consequence of thyroidectomy, causes dysfunction in lipid metabolism and liver enzymes resulting in secondary hyperlipidemia and liver dysfunction.