Enhanced proatherogenic inflammation after recombinant human TSH administration in patients monitored for thyroid cancer remnant

Recombinant or endogenous thyroid-stimulating hormone for radioactive iodine therapy in thyroid cancer: state of knowledge and current controversies

For patients undergoing radioiodine therapy (RIT) of differentiated thyroid carcinoma (DTC), thyroid-stimulating hormone (TSH) stimulation prior to RIT can be achieved using thyroid hormone withdrawal (THW) or administration of recombinant human TSH (rhTSH). As THW can lead to nausea, headaches, vomiting, fatigue, and dizziness secondary to transient acute hypothyroidism, rhTSH could be a good alternative. Recombinant human TSH has been administered in patients in order to stimulate TSH for RIT since 2005. According to the Martinique criteria formulated by the leading professional societies involved in care of patients with DTC, rhTSH can be applied in 3 settings: for remnant ablation, adjuvant treatment, and treatment of known disease. Numerous studies have investigated the effects of rhTSH as a method of TSH stimulation on the thyroid cell, the systemic effects, biokinetics, and clinical outcomes; however, no consensus has been reached about many aspects of its potential use. Recombinant human TSH is able to stimulate sufficient TSH levels (>30 mIU L-1) and is hypothesized to decrease risks of tumor cell proliferation. As rhTSH-use avoids the transiently impaired renal function associated with THW, radioiodine excretion is faster with the former, leading to a lower iodine-131 uptake and a difference in fractional remnant uptake, effective half-life, mean residence time, and dose to the blood. Differences between rhTSH and THW were observed in radioiodine genotoxic effects and endothelial-dependent vasodilation and inflammation. For thyroid remnant ablation, THW and rhTSH lead to similar remnant ablation rates. For adjuvant therapy and treatment of known disease, insufficient trials have been conducted and future prospective studies are recommended. The current review provides a state-of-the-science overview on the issues and debates surrounding TSH stimulation through either rhTSH adminsitration orendogenous TSH production after levothyroxin withdrawal.

The Prognostic Value of Thyroid-Stimulating Hormone in Patients with Coronary Artery Disease and Depression

Purpose

Patients with the comorbidity of coronary artery disease (CAD) and depression are very common and always have poor prognosis. The relationship between thyroid-stimulating hormone (TSH) levels and major cardiovascular event (MACE) in these patients is still unknown. We aimed to explore this association.

Patients and Methods

We enrolled 203 CAD patients proven by coronary angiography (CAG). In the meanwhile, they were all assessed to have depression symptom by professional psycho-cardiologists. After an average follow-up of 23.7 months, patients were divided into two groups (high TSH group with TSH ≥ 1.395μIU/mL and low TSH group with TSH < 1.395μIU/mL) according to the cut-off value of baseline TSH. The impact of two different TSH groups for adverse events in CAD patients with depression was evaluated.

Results

The average age of these patients was 64.9 years old. The two TSH groups had no significant difference in the comparison of other baseline data. Area under the receiver operating characteristic (ROC) curves (AUC) analysis indicated the well-discriminatory power of TSH levels for the occurrence of MACE (AUC = 0.61, 95% CI: 0.52–0.70, P = 0.03). In the KM survival analysis, high TSH group had a higher risk of MACE (P = 0.029). After multi-factor adjustment, there still existed a higher risk of MACE in high TSH group (HR = 2.05, 95% CI: 1.08–3.88, P = 0.028).

Conclusion

In patients with the comorbidity of CAD and depression, higher TSH levels are associated with the occurrence of MACE. More researches need to be conducted to prove this association and explore whether the drug-related TSH reduction can decrease the occurrence of adverse events in the future.

Aspirin resistance mediated by oxidative stress-induced 8-Isoprostaglandin F2

WHAT IS KNOWN AND OBJECTIVE

Aspirin resistance refers to a patient's poor response to aspirin. There are many factors that can contribute to aspirin resistance, including single-nucleotide polymorphisms, medication compliance, drug-drug interactions and inflammation.

COMMENT

Recently, oxidative stress-induced 8-isoprostaglandin F2α has attracted considerable attention because it is considered as a mechanism of aspirin resistance in many diseases, including coronary artery disease, neurology system disease, metabolic syndrome, cancer, chronic obstructive pulmonary disease and chronic kidney disease. In these diseases, increased oxidative stress may promote platelet activation and reduce the efficacy of aspirin by producing excessive amounts of 8-isoprostaglandin F2α.

WHAT IS NEW AND CONCLUSION

Given the wide clinical use of aspirin, it is essential to understand why some patients do not response to it. This article reviews current research on aspirin resistance mediated by oxidative stress-induced 8-isoprostaglandin F2α.

Effects of thyroid-stimulating hormone on adhesion molecules and pro-inflammatory cytokines secretion in human umbilical vein endothelial cells

Atherosclerosis is a multifactorial disorder, which affects the arterial wall. It has been reported that, hypothyroidism and thyroid hormone deficiency are related to cardiovascular disorders. Also, endothelial dysfunction plays an essential role in the development of atherosclerosis. We aimed to evaluate the effects of thyroid-stimulating hormone (TSH) on pro-inflammatory tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), angiogenic vascular endothelial growth factor (VEGF) and leukocyte adhesion, intercellular adhesion molecule 1 (ICAM-1) and E-selectin in human umbilical vein endothelial cells (HUVECs). In this study, HUVEC cells were treated with 1 and 2 μM of TSH in different treatment times. The gene and protein expression of ICAM-1, VEGF, and E-selectin were performed by real-time polymerase chain reaction and western blotting, respectively. Likewise, TNF-α and IL-6 protein levels were determined by the ELISA method. VEGF, ICAM-1, and E-selectin as endothelial dysfunction markers and also, TNF-α and IL-6 as pro-inflammatory cytokines were detectable in HUVEC. Besides, the results of this study revealed that TSH treatment down-regulates TNF-α and IL-6. Evaluating the gene and protein expression data revealed the upregulation of ICAM-1, E-selectin, and VEGF in TSH treated cases in different periods of exposure. Considering the multiple actions of TSH, it could be concluded that TSH plays a controversial role in atherogenesis by anti-inflammatory effects and on the other side, angiogenesis and leukocyte adhesion induction which is related to vascular cell proliferation.

Association of serum thyrotropin levels with coronary artery disease documented by quantitative coronary angiography: a transversal study

OBJECTIVE

The association between coronary artery disease (CAD) and thyroid function remains controversial. We evaluated the thyroid function and graduated well-defined CAD as confirmed by quantitative coronary angiography (CA).

SUBJECTS AND METHODS

We evaluated the serum TSH, free thyroxine, free triiodothyronine and thyroid antibody levels in 300 consecutive patients (age 61.6 ± 9.9 years and 54% were male) undergoing CAD diagnosis as confirmed by CA. Plaques with ≥ 50% stenosis being indicative of obstructive CAD, and patients were divided into groups according to main epicardial coronary arteries with plaques (0, 1, 2, 3). Lipid profiles and a homeostasis model assessment (HOMA-IR) were determined.

RESULTS

Serum median (25% and 75% percentile) TSH levels in patients with group 2 and 3 (2.25; 1.66-3.12 mU/L and 4.99; 4.38-23.60 mU/L, respectively) had significantly higher TSH concentrations (p < 0.0001) than the group 0 (1.82; 1.35-2.51 mU/L). Furthermore, patients of group 3 had higher TSH concentration (p < 0.0001) than those of group 1 (1.60; 0.89-2.68 mU/L). Group 3 were older (64 ± 8.5 vs. 59 ± 9.5, p = 0.001), had more patients with dyslipidemia (84% versus 58%, p < 0.001), male (54% versus 44%, p = 0.01), hypertension (100% versus 86%, p < 0.001), and smoking (61% versus 33%, p < 0.001) than group 0. Multivariate stepwise logistic analysis showed TSH, age, HbA1c, and HOMA-IR were the CAD associated variables.

CONCLUSIONS

In this cohort, elevated TSH levels in the high normal range or above are associated with the presence and severity of CAD besides may represent a weak CAD risk factor.

Replacement therapy with levothyroxine modulates platelet activation in recent-onset post-thyroidectomy subclinical hypothyroidism

BACKGROUND AND AIM

Subclinical hypothyroidism has been linked to increased risk of atherosclerotic disease. Soluble CD40 ligand (sCD40L), mainly derived from activated platelets, and the lipid peroxidation product 8-iso-prostaglandin F_2α (8-iso-PGF_2α) are known to play a relevant pathophysiological role in atherogenesis. In this study, we analyzed the relationship between thyroid hormones and circulating levels of sCD40L and 8-iso-PGF_2α in patient with recent-onset post-thyroidectomy subclinical hypothyroidism under replacement therapy.

METHODS AND RESULTS

Circulating levels of thyroid hormones, sCD40L, and 8-iso-PGF_2α were assessed in 40 recently thyroidectomized patients (33 females, mean age 52.0 ± 11.7 years) at baseline (5-7 day after surgery) and after 2 months under replacement therapy with levothyroxine (LT-4). At baseline, circulating levels of thyroid hormones were indicative of a subclinical hypothyroidism (TSH 7.7 ± 3.9 μU/mL, FT3 1.8 ± 0.6 pg/mL, and FT3 8.9 ± 3.0 pg/mL). Circulating levels of sCD40L and 8-iso-PGF_2α were directly correlated with each other (r = 0.360, p = 0.023) and with TSH levels (r = 0.322, p = 0.043 and r = 0.329 p = 0.038, respectively). After 2 months under the replacement therapy with LT-4 circulating levels of TSH (from 7.7 ± 3.9 to 2.7 ± 2.8 μU/mL, p < 0.0001), sCD40L (from 6.11 ± 2.41 to 2.43 ± 2.00 ng/mL, p < 0.0001) and 8-iso-PGF_2α (from 45.33 ± 6.94 to 40.36 ± 6.20, p < 0.0001) significantly decreased. Changes in circulating levels of sCD40L and 8-iso-PGF_2α were directly correlated with each other (r = 0.349 p = 0.028) and with changes in TSH levels (r = 0.367 p = 0.020 and r = 0.339 p = 0.032, respectively).

CONCLUSION

Our study suggests an influential role of TSH on proatherogenic activation of platelets, probably through enhanced lipid peroxidation. These findings could partially explain the increased susceptibility of patients with subclinical hypothyroidism to develop atherosclerotic disease.

Serum Thyroid Stimulating Hormone Levels Are Associated with the Presence of Coronary Atherosclerosis in Healthy Postmenopausal Women

Objectives

Menopause is a natural aging process causing estrogen deficiency, accelerating atherogenic processes including dyslipidemia. Prevalence of thyroid dysfunction is also high in postmenopausal women, and it is known to elevate the risk of cardiovascular disease (CVD). Therefore, we are to study on the associations in between serum thyroid stimulating hormone (TSH) and prevalence of CVD in postmenopausal women who have normal thyroid function.

Methods

We performed a retrospective review of 247 Korean postmenopausal women who visited the health promotion center from January, 2007 to December, 2009. Postmenopausal women with normal serum TSH were included in the study. Coronary atherosclerosis was assessed by 64-row multidetector computed tomography.

Results

In multiple linear regression analysis, serum TSH was associated with serum triglyceride (TG) (β = 0.146, P = 0.023). In multiple logistic regression analysis, increasing age and serum TSH were associated with an increased risk of coronary atherosclerosis in euthyroid postmenopausal women (odds ratio [OR] = 1.107 [1.024-1.197], P = 0.011 and OR = 1.303 [1.024-1.658], P = 0.031, respectively).

Conclusions

It revealed that significant predictor of serum TSH was serum TG, and increasing age and TSH were found to have associations with an increased risk of coronary atherosclerosis in euthyroid postmenopausal women. Screening and assessing risks for CVD in healthy postmenopausal women would be helpful before atherosclerosis develops.

Subclinical Hypothyroidism - What is Responsible for its Association with Cardiovascular Disease?

Subclinical hypothyroidism (SH) is a common condition, with prevalence estimates ranging from 4–20%, depending on the population demographics. Although epidemiological analysis associates it with an increased risk of cardiovascular disease, clinical practice guidelines express uncertainty about whether to monitor or to treat. As we await large-scale, well-designed randomised clinical trials regarding treatment of SH, a review of pathophysiological considerations may be informative to better understand this disorder.

The relationship between TSH and systemic inflammation in extremely preterm newborns

Elevated thyrotropin (TSH) levels in critically ill extremely premature infants have been attributed to transient hypothyroidism of prematurity or non-thyroidal illness syndrome. We evaluated the hypothesis that relatively high TSH levels in the first 2 postnatal weeks follow recovery from systemic inflammation, similar to non-thyroidal illness syndrome. The study was conducted in 14 Neonatal Intensive Care Units and approved by each individual Institutional Review Board. We measured the concentrations of TSH and 25 inflammation-related proteins in blood spots obtained on postnatal days 1, 7, and 14. We then evaluated the temporal relationships between hyperthyrotropinemia (HTT), defined as a TSH concentration in the highest quartile for gestational age and postnatal day, and elevated levels of inflammation-related proteins. 880 newborns less than 28 weeks of gestation were included. Elevated concentrations of inflammation-related proteins during the first or second week did not precede day-14 HTT. Systemic inflammation on day 7 was associated with day-14 HTT only if inflammation persisted through the end of the 2 week period. HTT frequently accompanied elevated concentrations of inflammation-related proteins on the same day. The hypothesis that HTT follows recovery from severe illness, defined as preceding systemic inflammation, is weakly supported by our study. Our findings more prominently support the hypothesis that TSH conveys information about concomitant inflammation in the extremely premature newborn.

Potential use of recombinant human thyrotropin in the treatment of distant metastases in patients with differentiated thyroid cancer

OBJECTIVE

In order to effectively treat differentiated thyroid cancer (DTC) with radioiodine (RAI) it is necessary to raise serum TSH levels either endogenously by thyroid hormone withdrawal (THW) or exogenously by administration of recombinant human TSH (rhTSH). The goal of this review is to present current data on the relative efficacy and side effects profile of rhTSH-aided versus THW-aided RAI therapy for the treatment of patients with distant metastases of DTC.

METHODS

We have searched the PubMed database for articles including the keywords "rhTSH", "thyroid cancer", and "distant metastases" published between January 1, 1996 and January 7, 2012. As references, we used clinical case series, case reports, review articles, and practical guidelines.

RESULTS

Exogenous stimulation of TSH is associated with better quality of life because it obviates signs and symptoms of hypothyroidism resulting from endogenous TSH stimulation. The rate of neurological complications after rhTSH and THW-aided RAI therapy for brain and spine metastases is similar. The rate of leukopenia, thrombocytopenia, xerostomia, and pulmonary fibrosis is similar after preparation for RAI treatment with rhTSH and THW. There is currently a controversy regarding RAI uptake in metastatic lesions after preparation with rhTSH versus THW, with some studies suggesting equal and some superior uptake after preparation with THW. Analysis of available retrospective studies comparing survival rates, progression free survival, and biochemical and structural response to a dosimetrically-determined dose of RAI shows similar efficacy after preparation for therapy with rhTSH and THW.

CONCLUSION

The rhTSH stimulation is not presently approved by the FDA as a method of preparation for adjunctive therapy with RAI in patients with metastatic DTC. Data on rhTSH compassionate use suggest that rhTSH stimulation is as equally effective as THW as a method of preparation for dosimetry-based RAI treatment in patients with RAI-avid metastatic DTC.

Radioiodine therapy in benign thyroid diseases: effects, side effects, and factors affecting therapeutic outcome

Radioiodine ((131)I) therapy of benign thyroid diseases was introduced 70 yr ago, and the patients treated since then are probably numbered in the millions. Fifty to 90% of hyperthyroid patients are cured within 1 yr after (131)I therapy. With longer follow-up, permanent hypothyroidism seems inevitable in Graves' disease, whereas this risk is much lower when treating toxic nodular goiter. The side effect causing most concern is the potential induction of ophthalmopathy in predisposed individuals. The response to (131)I therapy is to some extent related to the radiation dose. However, calculation of an exact thyroid dose is error-prone due to imprecise measurement of the (131)I biokinetics, and the importance of internal dosimetric factors, such as the thyroid follicle size, is probably underestimated. Besides these obstacles, several potential confounders interfere with the efficacy of (131)I therapy, and they may even interact mutually and counteract each other. Numerous studies have evaluated the effect of (131)I therapy, but results have been conflicting due to differences in design, sample size, patient selection, and dose calculation. It seems clear that no single factor reliably predicts the outcome from (131)I therapy. The individual radiosensitivity, still poorly defined and impossible to quantify, may be a major determinant of the outcome from (131)I therapy. Above all, the impact of (131)I therapy relies on the iodine-concentrating ability of the thyroid gland. The thyroid (131)I uptake (or retention) can be stimulated in several ways, including dietary iodine restriction and use of lithium. In particular, recombinant human thyrotropin has gained interest because this compound significantly amplifies the effect of (131)I therapy in patients with nontoxic nodular goiter.