Non-surgical approach to the benign nodular goiter: new opportunities by recombinant human TSH-stimulated 131I-therapy

The EANM guideline on radioiodine therapy of benign thyroid disease

This document provides the new EANM guideline on radioiodine therapy of benign thyroid disease. Its aim is to guide nuclear medicine physicians, endocrinologists, and practitioners in the selection of patients for radioiodine therapy. Its recommendations on patients' preparation, empiric and dosimetric therapeutic approaches, applied radioiodine activity, radiation protection requirements, and patients follow-up after administration of radioiodine therapy are extensively discussed.

Xiao-Luo-Wan treats propylthiouracil-induced goiter with hypothyroidism in rats through the PI3K-AKT/RAS pathways based on UPLC/MS and network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Goiter with hypothyroidism occurs in several thyroid diseases. Xiao-Luo-Wan (XLW), which contains Scrophularia ningpoensis Hemsl., Fritillaria thunbergii Miq. and Ostrea gigas Thunberg, has been used as an effective Chinese medicine for the treatment of goiters in China for hundreds of years. Based on clinical observations and experimental studies, XLW also exerts a certain effect on hypothyroidism. However, the therapeutic mechanism of XLW remains unclear.

AIM OF THE STUDY

The present study aimed to investigate the therapeutic effect of XLW on propylthiouracil (PTU)-induced goiter with hypothyroidism in rats and to uncover the underlying molecular mechanism using ultra high-performance liquid chromatography-mass spectrometry (UPLC/MS), network pharmacology, and molecular docking simulations.

MATERIALS AND METHODS

After successful modeling, the remaining rats were randomly divided into a model group, an Euthyrox group, an XLW group, and a control group. The corresponding drugs were given by gavage for four consecutive weeks. The growth status was monitored, the relative thyroid weight was calculated, and the total serum T3, T4, and TSH content were detected. Hematoxylin-eosin (H&E) staining was used to observe the pathological changes in the thyroid glands. The chemical components of the XLW were identified by UPLC/MS and the putative targets of XLW were predicted using multiple databases. We performed network pharmacology based on the intersection of goiter/hypothyroidism-related targets and XLW targets. Then, we performed KEGG pathway enrichment analysis, and key targets were further screened using protein-protein interaction (PPI) networks. Finally, molecular docking was used to predict the binding ability of XLW identified components and the key targets.

RESULTS

XLW significantly increased the levels of T3 and T4, and reduced TSH, increased body weight, and decreased swollen thyroid glands in PTU-induced rats. XLW promoted the morphological recovery of thyroid follicles and epithelial cells. Twenty-one main chemical components of XLW were identified using UPLC/MS. 270 potential gene targets of XLW and 717 known targets of goiter/hypothyroidism disease were obtained by searching the Traditional Chinese Medicine Systems Pharmacology Database (TCMSP), Swiss Target Prediction, and UniProt databases. A total of 83 KEGG pathways were enriched with phosphatidylinositol 3-kinase-protein kinase B (PI3K-AKT) and RAS signaling pathways. PPI analysis revealed nine key targets of kinase-protein kinase B (AKT) 1, interleukin (IL) 6, vascular endothelial growth factor A (VEGFA), tumor necrosis factor (TNF), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), epidermal growth factor receptor (EGFR), GTPase HRas (HRAS), matrix metalloproteinase (MMP) 9, and heat shock protein 90 alpha family class A member 1 (HSP90AA1). Molecular docking verified which drug components had good binding ability to key targets (all ≤5 kcal/mol).

CONCLUSION

For PTU-induced goiter with hypothyroidism in rats, XLW improves thyroid function, reduces goiter, increases body weight, and promotes the recovery of thyroid follicles and epithelial cells. The underlying molecular mechanism suggests that XLW may regulate thyroid hormone signaling by regulating the PI3K-AKT, RAS, and other signaling pathways. This study provides a pharmacological and biological basis for using XLW to treat goiter with hypothyroidism.

Recombinant Human Thyrotropin-Stimulated Radioiodine Therapy in Patients with Multinodular Goiters: A Meta-Analysis of Randomized Controlled Trials

A potential reduction of goiter volume (GV) of recombinant human thyrotropin (rhTSH) on multinodular goiters (MNG) was previously reported but controversial. Hence we conducted a meta-analysis to estimate the effect of rhTSH-stimulated radioiodine therapy in patients with MNG. PubMed, Cochrane, CNKI, VIP, and Wanfang databases were searched. Mean difference (MD) and odds ratios with 95% confidence intervals (95% CI) were derived by using an inverse variance random-effects model and fixed-effects model, respectively. Six studies (n=237) were involved in the analysis. For 12 months follow up, high dose (>0.1 mg) of rhTSH significantly reduced GV (MD=17.61; 95% CI=12.17 to 23.04; p<0.00001) compared with placebo. No effective pooled results of low dose of rhTSH (<0.1 mg) were applicable for only one study included. For 6 months follow up, the source of heterogeneity was determined by subgroup and sensitivity analysis. High dose group showed vast improvement in GV reduction (MD=16.62; 95% CI=1.34 to 31.90; p=0.03). The reduction of low dose group compared with placebo was inferior to high dose group. No available data were obtained to assess the influence of rhTSH after 36 months follow up for the only included study. Hypothyroidism incidence was higher for rhTSH group. No publication bias was seen. High dose of rhTSH treatment-stimulated radioactive ¹³¹I therapy after 6 months and 12 months follow up had a better effect in reducing GV, but with higher incidence of hypothyroidism. Owing to the limited methodological quality, more clinical researches are warranted in the future.

Enhancing the efficacy of 131I therapy in non-toxic multinodular goitre with appropriate use of methimazole: an analysis of randomized controlled study

PURPOSE

It is possible to raise the rate of the uptake of ¹³¹I in the thyroid gland (RAIU) by increasing the endogenous TSH level through appropriate use of methimazole (MMI) prior to ¹³¹I therapy. The purpose of this paper is to assess the impact of pre treatment with MMI on the efficacy of ¹³¹I therapy in non-toxic multinodular goitre (NMG).

METHODS

Thirty-one patients with NMG received ¹³¹I treatment in order to reduce the volume of the thyroid (TVR). Those in group 1 (n = 16) were administered 10 mg of methimazole for 6 weeks. Four days after its discontinuation, they received ¹³¹I. Patients in group 2 (n = 15) were given a placebo instead of MMI. The therapeutic activity of ¹³¹I was constant (800 MBq) and was repeated every 6 months. Treatment was discontinued when TVR reached <40 ml.

RESULTS

In group 1, RAIU increased approximately twofold. Ten patients from group 2 and four patients from group 1 received further doses of ¹³¹I. The median of time until TVR decreased below 40 ml was 9 months [6-12 months] and 18 months [14-22 months] in group 2. At 2 years after the ¹³¹I therapy, the occurrence of hypothyroidism did not differ significantly (36% in group 1 and 33% in group2, p = 0.074).

CONCLUSIONS

Radioiodine treatment of NMG preceded with appropriate application of MMI is efficient thanks to increased RAIU, shorter period of treatment, and lower frequency of ¹³¹I administration, without an increase in the incidence of post-treatment hypothyroidism.

Thyroid hormone synthesis: a potential target of a Chinese herbal formula Haizao Yuhu Decoction acting on iodine-deficient goiter

Haizao Yuhu Decoction (HYD), a famous multi-component herbal formula, has been widely used to treat various thyroid-related diseases, including iodine-deficient goiter. Herb pair Thallus Sargassi Pallidi (HZ) and Radix Glycyrrhizae (GC), one of the so-called “eighteen antagonistic medicaments”, contains in HYD. To explore pharmacological mechanisms of HYD acting on iodine-deficient goiter and to provide evidence for potential roles of herb pair HZ and GC in HYD, our genome-wide microarray detection and network analysis identified a list of goiter-related genes, mainly involved into the alterations in hypothalamus-pituitary-thyroid/gonad/growth axes. Then, the disease genes-drug genes interaction network illustrated the links between HYD regulating genes and goiter-related genes, and identified the candidate targets of HYD acting on goiter. Functionally, these candidate targets were closely correlated with thyroid hormone synthesis. Moreover, the potential regulating genes of herb pair HZ and GC were revealed to be crucial components in the pathway of thyroid hormone synthesis. The prediction results were all verified by following experiments based on goiter rats. Collectively, this integrative study combining microarray gene expression profiling, network analysis and experimental validations offers the convincing evidence that HYD may alleviate iodine-deficient goiter via regulating thyroid hormone synthesis, and explains the necessity of herb pair HZ and GC in HYD. Our work provides a novel and powerful means to clarify the mechanisms of action for multi-component drugs such as herbal formulae in a holistic way, which may improve drug development and applications.

Recombinant human TSH and radioactive iodine therapy in the management of benign multinodular goiter

Multinodular goiter (MNG) is a very common thyroid disorder determined by diverse goitrogenic factors, the most important one being iodine deficiency. The clinical presentation of a patient with MNG varies from a completely asymptomatic goiter to a life-threatening disease due to upper airway compression. Patients can develop underlying subclinical or overt hyperthyroidism due to autonomously hyperfunctioning nodules. In the absence of clinical, ultrasonographic, or cytological findings suggestive of malignancy, the best therapeutic approach for a patient with MNG will depend on the size and location of the goiter, the presence and severity of compressive symptoms, and the presence or absence of thyrotoxicosis. There is still no consensus regarding the treatment of atoxic MNGs. Hence, its optimal management remains controversial; possible therapies include levothyroxine (lT4), surgery, and radioactive iodine ((131)I). Suppressive treatment with lT4 is discouraged due to the development of sub-clinical or overt hyperthyroidism and to its low efficacy when compared with surgery or (131)I. Total thyroidectomy is effective; however, it is associated with the risk of surgical complications and is often refused by the patient. (131)I therapy is an alternative to thyroid surgery to reduce the size of benign MNGs. Based on the ability of recombinant human TSH (rhTSH) to more than double thyroid (131)I uptake, this compound has been evaluated as an adjuvant to (131)I in the treatment of MNG. Very small doses of rhTSH have been used in patients with MNG and few safety concerns have been observed, but the ideal dose, both effective and safe, is yet to be defined.

Complications in thyroid resurgery: a single institutional experience on 233 patients from a whole series of 4,752 homogeneously treated patients

The aim of this study was to examine a homogeneous, consecutive recent series of patients who underwent reoperation on the thyroid bed to assess the incidence of the complications commonly correlated with resurgery. We reviewed clinical charts of 233 patients who underwent resurgery taken from a total of 4,752 patients previously operated on for benign and malignant thyroid diseases from 2006 to 2010 by the same surgical team. We evaluated the incidence of postoperative hemorrhage, hypoparathyroidism, and recurrent laryngeal nerve (RLN) palsy. Analyses were done separately in relation to the type of the type of resurgery adopted: (A) monolateral completion; (B) bilateral completion, after monolateral (B1) or bilateral prior surgery (B2); and (C) lymph node dissection. We also separately analyzed patients according to their final histological diagnosis of benign or malignant disease. Regarding hemorrhage, 6/233 patients (2.5 %) underwent surgical revision of the thyroid within 12 h for postoperative hemorrhage. They included 2 (1.5 %) of the 129 monolateral reoperations (A), 3 (4 %) of the 74 bilateral reoperations (B), and 1 (3.3 %) of the 30 central dissections for nodal relapse (C). Transient and definitive postoperative hypoparathyroidism was recorded in 78 (36.4 %) and 7 (3.3 %) of the 214 eligible patients. Transient RLN palsy occurred in 21 RLNs at risk (7 %) and definitive RLN palsy in 5 (1.7 %). Elective total thyroidectomy cannot always be supported as an effective policy for preventing recurrences in patients with a single, benign node: lobectomy, preferably with extemporaneous histological examination, unquestionably represents the best minimal approach to thyroid resection.

The role of radioiodine therapy in benign nodular goitre

For treatment of benign nodular goitre the choice usually stands between surgery and (131)I therapy. (131)I therapy, used for 30 years for this condition, leads to a goitre volume reduction of 35-50% within 1-2 years. However, this treatment has limited efficacy if the thyroid (131)I uptake is low or if the goitre is large. Recombinant human TSH (rhTSH)-stimulated (131)I therapy significantly improves goitre reduction, as compared with conventional (131)I therapy without pre-stimulation, and adverse effects are few with rhTSH doses of 0.1 mg or lower. RhTSH-stimulated (131)I therapy reduces the need for additional therapy due to insufficient goitre reduction, but the price is a higher rate of hypothyroidism. Another approach with rhTSH-stimulation is to reduce the administered (131)I activity by a factor that equals the increase in the thyroid (131)I uptake. Using this approach, radiation exposure is considerably reduced while the goitre reduction is similar to that obtained with conventional (131)I therapy.

The calcium-phosphate balance, modulation of thyroid autoimmune processes and other adverse effects connected with thyroid arterial embolization

In search of new treatment options for thyroid diseases, when conventional procedures are ineffective, contraindicated or associated with serious side effects, safety of thyroid arteries embolization in the treatment of particular thyroid diseases was evaluated. The study included eight subjects with retrosternal toxic goiter, six patients affected by Graves' disease, five cases of retrosternal non-toxic goiter, two subjects with post-amiodarone hyperthyroidism, and one patient with severe thyroid-related orbitopathy, who underwent selective embolization of thyroid arteries. The study assessed and compared calcium-phosphate balance, modulation of thyroid autoimmunity and the presence of different side effects in patients who underwent the procedure. In addition, the serum concentrations of thyroid hormones, anti-thyroid autoantibodies and thyroid volume have been measured. Five of all enrolled subjects (22.7 %) experienced transient, not clinically relevant hypocalcaemia with no need for calcium supplementation. There were no significant changes in serum calcium levels in patients after embolization of both inferior thyroid arteries. The transient side effects associated with the treatment were neck pain and a slight increase in body temperature. Noted high concentration of free thyroid hormones immediately after the procedure was not accompanied by worsening of symptoms or signs of thyrotoxicosis. In patients with Graves' disease, a significant decrease in thyrotropin receptor antibodies level was observed. Thyroid arterial embolization does not disturb permanently calcium-phosphate balance, modulates positively thyroid autoimmune processes and is associated with no serious post-procedure side effects. Hence, it may be considered as a safe and effective treatment modality for selected thyroid disorders.

Radioiodide induces apoptosis in human thyroid tissue in culture

Radioiodide ((131)I) is routinely used for the treatment of toxic adenoma, Graves' disease, and for ablation of thyroid remnant after thyroidectomy in patients with thyroid cancer. The toxic effects of ionizing radiations on living cells can be mediated by a necrotic and/or apoptotic process. The involvement of apoptosis in radiation-induced cell death in the thyrocytes has been questioned. The knowledge of the mechanisms that underlie the thyrocyte death in response to radiations can help to achieve a successful treatment with the lowest (131)I dose. We developed a method to study the effects of (131)I in human thyroid tissue in culture, by which we demonstrated that (131)I induces thyroid cell apoptosis. Human thyroid tissues of about 1 mm(3) were cultured in vitro and cell viability was determined up to 3 weeks by the MTT assay. Radioiodide added to the culture medium was actively taken up by the tissues. The occurrence of apoptosis in the thyrocytes was assessed by measuring the production of a caspase-cleavage fragment of cytokeratin 18 (M30) by an enzyme-linked immunoassay. Neither variation of cell number nor spontaneous apoptosis was revealed after 1 week of culture. (131)I added to the culture medium induced a dose-dependent and a time-dependent generation of M30 fragment. The apoptotic process was confirmed by the generation of caspase-3 and PARP cleavage products. These results demonstrate that (131)I induces apoptosis in human thyrocytes. Human thyroid tissue cultures may be useful to investigate the cell death pathways induced by (131)I.

Thyroid nodules and differentiated thyroid cancer: update on the Brazilian consensus

Thyroid nodules are frequent findings, especially when sensitive imaging methods are used. Although thyroid cancer is relatively rare, its incidence is increasing, particularly in terms of small tumors, which have an uncertain clinical relevance. Most patients with differentiated thyroid cancer exhibit satisfactory clinical outcomes when treatment is appropriate, and their mortality rate is similar to that of the overall population. However, relapse occurs in a considerable fraction of these patients, and some patients stop responding to conventional treatment and eventually die from their disease. Therefore, the challenge is how to identify the individuals who require more aggressive disease management while sparing the majority of patients from unnecessary treatments and procedures. We have updated the Brazilian Consensus that was published in 2007, emphasizing the diagnostic and therapeutic advances that the participants, representing several Brazilian university centers, consider most relevant in clinical practice. The formulation of the present guidelines was based on the participants' experience and a review of the relevant literature.

Prestimulation with recombinant human thyrotropin (rhTSH) improves the long-term outcome of radioiodine therapy for multinodular nontoxic goiter

OBJECTIVE

The objective of the study was to evaluate the long-term outcome of recombinant human TSH (rhTSH)-augmented radioiodine ((131)I) therapy for benign multinodular nontoxic goiter.

PATIENTS AND METHODS

Between 2002 and 2005, 86 patients with a multinodular nontoxic goiter were treated with (131)I in two randomized, double-blind, placebo-controlled trials. (131)I-therapy was preceded by 0.3 mg rhTSH (n = 42) or placebo (n = 44). In 2009, 80 patients completed a follow-up (FU) visit, including determination of thyroid volume, thyroid function, and patient satisfaction by a visual analog scale.

RESULTS

In both groups, thyroid volume was further reduced from 1 yr to final FU (71 months). The mean goiter volume reductions obtained at 1 yr and final FU [59.2 ± 2.4% (sem) and 69.7 ± 3.1%, respectively] in the rhTSH group were significantly greater than those obtained in the (131)I-alone group (43.2 ± 3.7 and 56.2 ± 3.6%, respectively, P = 0.001 and P = 0.006), corresponding to a gain of 24% at final FU. At last FU the mean reduction in compression visual analog scale score was significantly greater in patients receiving rhTSH (P = 0.049). Additional therapy (thyroid surgery or (131)I) was required more often in the placebo group (nine of 44) compared with the rhTSH group (two of 42) (P = 0.05). The prevalence of hypothyroidism at 1 yr [9 and 43% in the placebo and rhTSH groups, respectively (P < 0.0001)] increased to 16 and 52%, respectively, at final FU (P = 0.001).

CONCLUSION

Enhanced goiter volume reduction with rhTSH-augmented (131)I therapy improves the long-term reduction in goiter-related symptoms and reduces the need for additional therapy compared with plain (131)I therapy. Overall patient satisfaction is benefited, despite a higher rate of permanent hypothyroidism.