Low Iodine Diet Research Articles

6404 Iodide Metabolism Anomalies in Patients with Thyroid Cancer; A Case Series

Abstract Disclosure: G.I. Uwaifo: None. Thyroid cancer is often treatable and often involves iodine ablation therapy. Iodine based imaging and/or therapy can be complicated in patients with abnormal iodide metabolism. We present two patients with thyroid cancer and disparate abnormal iodide metabolism. Case 1 is a 35 yr old Caucasian lady with papillary thyroid cancer (PTC) stage 1 with no metastases. After total thyroidectomy and prior to I-131 remnant ablation she had a contrast Chest CT for shortness of breath. A month after serum iodine was elevated (545 Ug/L; 40—92). 24 hr urine iodine levels was also elevated; (2,300Ug/day; 150-500). She denied dietary intake of iodine rich foods. Ablation was postponed and she commenced a strict “zero” iodine diet. Despite this and despite having no further contrast imaging serum and urinary iodine remain elevated for nearly 3 yrs. Further history indicated episodes of sensitivity to several medications and Cytochrome P450 genetic profiling revealed two polymorphisms of CYP P450 2C19 and 2D6 associated with slow drug metabolizer phenotype. 34 months after her Chest CT with serum iodine of 127Ug/L and 24 hr Urine iodine of 652 she had radio iodine-ablation (RIA) with 130Mci of I-131. She had post treatment dysgeusia and parotitis. She remains on a low iodine diet and is presumably cured. Case 2 is a 66 yr old Caucasian man referred for second opinion regarding therapeutic options for known metastatic PTC with metastases to thoracic spine and lungs. He was diagnosed with follicular variant PTC 7 yrs ago. He had total thyroidectomy and repeated RIAs with a total accumulated dose of ∼ 850Mci and last RIA 3 yrs ago. His latest two whole body I-131 scans were -ve despite elevated thyroglobulins and metastatic disease. He was unable to tolerate sorefanib. He is on thyroid hormone repletion and quarterly denosumab. Contrast PET-CT scan a week prior showed extensive metastatic disease and thyroglobulins in the 300—650 ng/ml range. Work up for repeat whole body I-131 scan revealed curiously that serum iodine was 46 Ug/L (40-92) despite his recent contrast study and this was confirmed on two repeats. 24 hr urine iodine was reduced; 87 ug/day (150-500) and he had a typical diet with no excess intake of goitrogens. Based on history of often needing significantly higher doses of medications like opioids, anesthetics and sedatives cytochrome P450 genetic profile obtained showed two polymorphisms (of CYP P450 2C-19 and CVPs 3A4 +3A5) associated with fast metabolizer phenotype. Given his unusually rapid iodine clearance the utility of any further iodine based imaging and/or therapy was deemed dubious. His current management continues without change. We present two patients with extremes of iodine metabolic processing that had clinical management significance. Careful evaluation of ambient iodine status of patients is an important part of the preparation of thyroid cancer patients for iodine based imaging and/or therapy. Presentation: 6/1/2024

Comparative Analysis of Oxidative Metabolism in Liver in Different Experimental Models of Hypothyroidism: Low Iodine Diet and Anti-Thyroid drug (Methimazole)

Objectives: On the concept of oxidative stress in hypothyroidism, which still remains ambiguous and controversial, the article emphasizes the issue of the impact of the experimental conditions on the validity of the data obtained in different methods of modeling thyroid dysfunction. Materials and Methods: Experiments were conducted on 112 white nonlinear male rats. Thyroid hormones and biomarkers of oxidative metabolism in the liver tissue were determined in rats kept for 3 months on a low-iodine diet (LID) and in rats with methimazole (MMI)-induced hypothyroidism (2,5 mg/100 g of body weight for 3 weeks). Results: In LID-rats (n=96) total serum T4 amounted 43, total T3 in liver tissue - 73% of the level found in euthyroid animal, p=0.0121 and p=0.0051, respectively), whereas in MMI-rats (n=96) both total and free serum T4 were 67% of control (p=0.0002 for both total and free T4). In LID-rats cytochrome oxidase (CcOX) activity in liver tissue was 68.5, concentration of malondialdehyde (MDA) - 58% of euthyroids (p value - 0.0202 and 0.0127, respectively), while protein carbonyls (PC) level was 116% of the control (p=0.0411). In MMI-rats liver malate dehydrogenase (MDH) activity decreased up to 70.9, but succinate dehydrogenase (SDH) activity and MDA concentration increased up to 163.6 and 154% of the level in euthyroid animals respectively (p˂0.05). Conclusion: LID-model led to the more pronounced inhibition of thyroid function, than that the MMI-hypothyroidism model used. LID-model was accompanied by a decrease in the intensity of oxidative metabolism in liver tissue, whereas MMI-hypothyroidism - by activation of the succinate oxidation pathway and an increase in the concentration of secondary lipid peroxidation products in the liver of experimental animals. The results suggest that the conflicting data obtained from studies of oxidative metabolism in hypothyroidism, among other assumptions, may be due to the different approaches used by researchers to model thyroid dysfunction.

Investigation on low-iodine diet implementation by medical staff before radioactive iodine treatment for differentiated thyroid carcinoma.

To explore the implementation of low-iodine diets by medical staff caring for patients with differentiated thyroid carcinoma prior to 131I therapy across 58 hospitals, and offer valuable insights for the development of guidelines on low-iodine diets. Convenience sampling was utilized to conduct a survey among 163 medical staff members working in nuclear medicine departments across 58 tertiary hospitals using a self-designed questionnaire. Concerning the duration of the low-iodine diet prior to treatment, the medical staff's recommendations were as follows: 58.28% suggested 2-4weeks, 31.29% recommended more than 4weeks, 9.2% opted for 7-13days, and 1.23% favored less than 1week. Regarding the timing of resuming a normal diet, the respondents' recommendations ranged from immediately after treatment (1.84%) to 3months post-treatment (8.58%), with intermediate recommendations of 2h (8.58%), 24-48h (14.11%), post-discharge (12.26%), and 1month (42.94%). Furthermore, the surveyed medical staff unanimously recommended abstaining from seafood, with 90.8% also advising against the consumption of iodized salt, 91.41% recommending avoidance of iodine-containing medications, and 71.17% advising caution with moderately high-iodine foods. Notably, 75.46% of the medical staff evaluated patient compliance with the low-iodine diet. When patients failed to adhere to the diet preparation, 33.74% of healthcare workers chose to proceed with treatment. In terms of guidance sources, 96.93% of respondents relied on relevant guidelines, 66.26% referred to the literature, and 49.69% drew upon their clinical experience. During hospitalization, 58.28% of the medical staff continued to guide patients on the low-iodine diet, while only 8.59% provided such guidance after discharge. Notably, only 20.25% of the staff considered consulting the nutrition department. This study underscored substantial variations in the duration and selection criteria for low-iodine diets, which were linked to a scarcity of standardized evaluations. Consequently, there is an urgent need for further research to establish detailed, practical, accessible, comprehensive, and dependable implementation programs for low-iodine diets.

Reducing anxiety and enhancing satisfaction in thyroid patients with DietLens application during radioactive iodine therapy: A quasi-experimental study

Hyperthyroidism and thyroid cancer significantly impact health, and often require Radioactive Iodine (RAI) therapy. Anxiety is common in patients undergoing RAI, particularly related to dietary compliance. This study aimed to assess the effectiveness of the mobile health application, DietLens in reducing anxiety and increasing satisfaction in patients preparing for RAI therapy, focusing on low-iodine diet (LID). A quasi-experimental study was conducted in a Singapore tertiary hospital outpatient department from March 13, 2019 to March 27, 2020, involving patients scheduled for their first RAI treatment. Participants were divided into a control group receiving standard care and an intervention group using DietLens alongside standard care. Anxiety levels were assessed using the Zung Self-Rating Anxiety Scale, and satisfaction levels were measured through self-reported questionnaires. In the study, 56 participants were initially divided into control (n = 28) and intervention (n = 28) groups. After accounting for dropouts, 50 participants finished the study, with each group comprising 25 individuals. Anxiety levels were similar between groups pre-intervention. Post-intervention, the intervention group displayed a significant decrease in anxiety levels compared to the control group (independent t-test: t (48) = 2.50, p = 0.02). The multivariate linear regression analysis indicated that being in the intervention group was significantly associated with a decrease in post-intervention anxiety score (β = −4.03, 95 % CI: −7.33 to −0.72, p = 0.02). Fisher's Exact Test revealed a borderline significant difference in satisfaction with educational materials and the overall treatment process, with 100 % of the intervention group expressing satisfaction compared to 80 % in the control group, resulting in a p-value of 0.052 in both instances. DietLens was effective in reducing anxiety and enhancing satisfaction related to RAI therapy preparation, particularly in managing a LID, highlighting a beneficial role for digital interventions in healthcare settings.

Vitamin D, selenium, and antidiabetic drugs in the treatment of type 2 diabetes mellitus with Hashimoto's thyroiditis.

Diabetes and thyroiditis are closely related. They occur in combination and cause significant damage to the body. There is no clear treatment for type-2 diabetes mellitus (T2DM) with Hashimoto's thyroiditis (HT). While single symptomatic drug treatment of the two diseases is less effective, combined drug treatment may improve efficacy. To investigate the effect of a combination of vitamin D, selenium, and hypo-glycemic agents in T2DM with HT. This retrospective study included 150 patients with T2DM and HT treated at The Central Hospital of Shaoyang from March 2020 to February 2023. Fifty patients were assigned to the control group, test group A, and test group B according to different treatment methods. The control group received low-iodine diet guidance and hypoglycemic drug treatment. Test group A received the control treatment plus vitamin D treatment. Test group B received the group A treatment plus selenium. Blood levels of markers of thyroid function [free T3 (FT3), thyroid stimulating hormone (TSH), free T4 (FT4)], autoantibodies [thyroid peroxidase antibody (TPOAB) and thyroid globulin antibody (TGAB)], blood lipid index [low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triacylglycerol (TG)], blood glucose index [fasting blood glucose (FBG), and hemoglobin A1c (HbA1c)] were measured pre-treatment and 3 and 6 months after treatment. The relationships between serum 25-hydroxyvitamin D3 [25 (OH) D3] level and each of these indices were analyzed. The levels of 25 (OH) D3, FT3, FT4, and LDL-C increased in the order of the control group, test group A, and test group B (all P < 0.05). The TPOAB, TGAB, TC, TG, FBG, HbA1c, and TSH levels increased in the order of test groups B, A, and the control group (all P < 0.05). All the above indices were compared after 3 and 6 months of treatment. Pre-treatment, there was no divergence in serum 25 (OH) D3 level, thyroid function-related indexes, autoantibodies level, blood glucose, and blood lipid index between the control group, test groups A and B (all P > 0.05). The 25 (OH) D3 levels in test groups A and B were negatively correlated with FT4 and TGAB (all P < 0.05). The combination drug treatment for T2DM with HT significantly improved thyroid function, autoantibody, and blood glucose and lipid levels.

GLIS3 expression in the thyroid gland in relation to TSH signaling and regulation of gene expression

Loss of GLI-Similar 3 (GLIS3) function in mice and humans causes congenital hypothyroidism (CH). In this study, we demonstrate that GLIS3 protein is first detectable at E15.5 of murine thyroid development, a time at which GLIS3 target genes, such as Slc5a5 (Nis), become expressed. This, together with observations showing that ubiquitous Glis3KO mice do not display major changes in prenatal thyroid gland morphology, indicated that CH in Glis3KO mice is due to dyshormonogenesis rather than thyroid dysgenesis. Analysis of GLIS3 in postnatal thyroid suggested a link between GLIS3 protein expression and blood TSH levels. This was supported by data showing that treatment with TSH, cAMP, or adenylyl cyclase activators or expression of constitutively active PKA enhanced GLIS3 protein stability and transcriptional activity, indicating that GLIS3 activity is regulated at least in part by TSH/TSHR-mediated activation of PKA. The TSH-dependent increase in GLIS3 transcriptional activity would be critical for the induction of GLIS3 target gene expression, including several thyroid hormone (TH) biosynthetic genes, in thyroid follicular cells of mice fed a low iodine diet (LID) when blood TSH levels are highly elevated. Like TH biosynthetic genes, the expression of cell cycle genes is suppressed in ubiquitous Glis3KO mice fed a LID; however, in thyroid-specific Glis3 knockout mice, the expression of cell cycle genes was not repressed, in contrast to TH biosynthetic genes. This indicated that the inhibition of cell cycle genes in ubiquitous Glis3KO mice is dependent on changes in gene expression in GLIS3 target tissues other than the thyroid.

The hypothalamic-pituitary-thyroid axis is intact in male insulin receptor substrate 4 knockout mice.

Loss of function mutations in the insulin receptor substrate 4 (IRS4) gene cause a rare form of X-linked congenital central hypothyroidism in boys and men. Affected individuals show decreased thyroid-stimulation hormone (TSH) secretion. Members of the IRS family canonically act as scaffold proteins between tyrosine kinase receptors and downstream effectors. How loss of IRS4 affects TSH synthesis or secretion is unresolved. We therefore assessed IRS4's role in the hypothalamic-pituitary-thyroid axis of Irs4 knockout mice. We generated two global Irs4 knockout mouse lines harboring either two or four base-pair deletions that result in frameshifts and loss of most of the IRS4 protein. Under normal laboratory conditions, Irs4 knockout males did not exhibit impairments in pituitary expression of TSH subunit genes (Tshb or Cga) or in the thyrotropin-releasing hormone (TRH) receptor. Additionally, their serum thyroid hormone, T3 (triiodothyronine) and T4 (thyroxine), and hypothalamic Trh expression levels were normal. When Irs4 knockouts were rendered hypothyroid with a low-iodine diet supplemented with propylthiouracil (PTU) for 3 weeks, their serum TSH increased similarly to wild-type males. Overall, Irs4 knockout mice do not exhibit central hypothyroidism or otherwise appear to phenocopy IRS4 deficient patients. Compensation by another IRS protein may explain euthyroidism in these animals.

Effects of Iodinated Contrast-enhanced CT on Urinary Iodine Levels in Postoperative Patients with Differentiated Thyroid Cancer.

This study aims to observe the fluctuating urine iodine levels in patients with differentiated thyroid cancer (DTC) following iodinated contrastenhanced computed tomography (eCT) scans. The presence of iodine in iodinated contrast agents (ICAs) can impede the effectiveness of radioactive iodine treatment (RAIT) and diagnostic scans in individuals diagnosed with DTC, as it can engage in competitive interactions with 131I. According to established guidelines, it is recommended to postpone RAIT for a period of three to four months in individuals who have had prior exposure to ICAS. The measurement of spot urine iodine concentration is a valuable indicator for assessing the overall iodine content throughout the body. The objective is to identify the optimal timing for administering postoperative RAIT in DTC patients. At various time points after surgery, a cohort of 467 random urine samples (126 male samples, 341 female samples, age (45±12 years)) was obtained from 269 DTC patients. The samples were analyzed for urinary iodine and urinary creatinine levels, and the urinary iodine/urine creatinine ratio (I/Cr) was computed. All samples were divided into two groups according to whether eCT before operation: the non-enhanced CT (eCT-) group and the enhanced CT (eCT+) group. The urine samples in the eCT- group were categorized into four subgroups according to the duration of strict low iodine diet (LID): (eCT-I+) no LID; (eCT-I-2W) 2 weeks of LID; (eCT-I-4W) 4 weeks of LID; and (eCT-I-6W) 6 weeks of LID. The last three groups were merged into the eCT- and effective LID group (eCT- I-). The urine samples from the eCT+ group were categorized into five subgroups: (0.5M eCT+)0.5 month after eCT+; (1M eCT+)1 month after eCT+; (2M eCT+) 2 months after eCT+; (3M eCT+) 3 months after eCT+; (≥4M eCT+) ≥4 months after eCT+. In addition, the patients within 2 months after eCT+ were divided into 2 groups according to their LID: no effective LID group (eCT+ I+) and effective LID group (eCT+ I-). Utilizing the Kruskal-Wallis and Mann-Whitney U rank sum tests, the differences in I/Cr between groups were compared. In the eCT-group, the I/Cr ratios of eCT-I-2W, eCT-I-4W, and eCT-I-6W were significantly lower than those of eCT-I+ (χ2 values: 4.607.99, all P 0.05). However, there was no significant difference in I/Cr between eCT-I-2W, eCT- I-4W, and eCT-I-6W (2 values: 0.591.31, all P > 0.05). Significantly higher I/Cr values were observed in 0.5M eCT+ and 1M eCT+ than in eCT-I+ (χ2 values: 3.22 and 2.18, respectively, all P<0.05). There was no significant difference in I/Cr between 2M eCT+ and eCT-I+ (χ2 = 0.76, P = 0.447). The I/Cr rations of 3M eCT+, ≥4M eCT+ were not significantly different with eCT-I- (χ2 values: 1.76; 0.58; all P > 0.05). However, they were considerably lower than eCT-I+ (χ2 values: 7.03; 5.22; all P<0.05). The I/Cr for patients who underwent eCT within two months (eCT+ I-, eCT+ I+) did not differ significantly (χ2 = 1.79, P = 0.073). For patients who are considering receiving radioactive iodine therapy (RAIT) following a diagnosis of differentiated thyroid cancer (DTC), it is recommended that the interval between RAIT treatment and enhanced computed tomography [eCT] scans be conducted at least three months.

Effect of previous administration of potassium iodine and different durations of low iodine diets for radioiodine therapy on the treatment of Graves' disease in iodine-rich areas.

To examine whether adherence to a low-iodine diet (LID) enhances the therapeutic efficacy of radioiodine therapy (RAI) in Graves' hyperthyroidism (GH) in iodine-rich areas. We retrospectively evaluated 185 patients with GH from Aichi (n = 114) and Hokkaido (n = 71) Prefectures. Patients aged ≥ 18years with GH who underwent RAI between December 2012 and March 2022 were divided into subgroups based on pretreatment with anti-thyroid drug (ATD) or potassium iodide (KI). Patients were followed up with LID from 18days (group A) or 7days (group H) before RAI to 3days after RAI. The dose of radioactive iodine 131 (131I) was adjusted to deliver > 100Gy to the thyroid. The associations between urinary iodine concentration on UIC2 vs. 24hRU and UIC2 vs. the 1-year RAI success rate (SR) were investigated. Compared with UIC1, UIC2 was significantly decreased in all subgroups (P < 0.01). An inverse correlation between UIC2 and 24hRU was observed in the four groups; however, the difference was insignificant. The SR in groups A and H was 85% and 89%, respectively. Univariate analysis revealed no association between UIC2 and SR in each group. Additionally, stratification of the 185 patients into quartiles using UIC2 yielded no significant differences in SR (p = 0.79). LID sufficiently reduced UIC in patients undergoing RAI. Although a lower UIC2 may increase 24hRU, it did not increase the success of RAI. The benefit of LID in enhancing the efficacy of RAI in GH treatment remains uncertain.

SAT490 Graves’ Disease In Remission Aggravated By Himalayan Salt Consumption

Abstract Disclosure: M.K. Shakir: None. K.F. Brown: None. J.S. Hatfield: None. N.O. Vietor: None. T.D. Hoang: None. Introduction: In iodine-replete countries, iodine-induced thyrotoxicosis may occasionally develop after ingestion or therapy with high doses of iodine. Recently, Himalayan salt has become very popular to bridge iodine deficiency, control hypothyroidism, and improve thyroid function. We report a patient with a history of treated Graves’ disease (GD) who developed acute thyrotoxicosis following the use of Himalayan salt. Case report: A 58-year-old woman presented with symptoms of heat intolerance, and unexpected 18-lbs weight loss over 3 months. Physical examination: HR 108 bpm, BP 110/70 mm Hg, normal eye examination, thyroid 45 gms, diffusely enlarged. Examinations of the heart, lungs and abdomen were normal. Lab tests: TSH 0.01 IU/mL, free T4 3.8 ng/dL, T3 308 pg/dL, thyrotropin receptor Ab 4.2 IU/L (&amp;lt;1.0), and thyroid stimulating immunoglobulin 1.89 1U/L (0.06-0.55). The I131 uptake was 60% at 4 hours and the thyroid scan revealed diffuse homogenous uptake confirming GD. She was treated with methimazole (MMI) for 2 years and remission was achieved. MMI was stopped and she remained euthyroid. Twelve months later, she developed hyperthyroid symptoms with a 15-lb weight loss, palpitations, and anxiety. Examination confirmed a 50-gram diffuse goiter and other physical findings consistent with hyperthyroidism. She admitted that she had been taking Himalayan salt (approximately 10 grams daily) in place of regular salt for the past 6 months. Lab tests confirmed recurrent GD: TSH &amp;lt;0.01 IU/mL, FT4 4.1 ng/dL, total T3 278 pg/dL, and I131 uptake was 55% at 24 hours. A 24-hours urine iodine was 898 mcg (normal 100-199) and plasma iodine level was 484 mcg/L (normal 52-109). A diagnosis of iodine-induced recurrence of GD was made, and she was treated with MMI and low iodine diet. After 3 months, she improved significantly and was able to discontinue the MMI by 6 months. A follow- up urine iodine was 189 mcg/L with a plasma iodine level of 78 mcg/L. Subsequently she remained euthyroid for an additional 18 months of follow-up without any treatment. Conclusion: The recommended daily dietary allowance for iodine in adults is 150mcg. Himalayan rock salt may provide a rich source of iodine and consumption of large amounts can lead to iodine excess. However, the available studies do not provide the iodine content in commercially available Himalayan salt preparations. Although the Himalayan salt is advertised to have beneficial effects in patients with thyroid disorders, this food supplement may have deleterious effects in susceptible patients who do not have iodine deficiency, have GD, or are at risk for thyrotoxicosis. Indeed, Himalayan salt use exacerbated GD in our patient, as evidenced by iodine overdose during acute exacerbation and resolution of GD with iodine normalization and low dose MMI. We recommend that patients with thyroid disorders be educated regarding Himalayan salt use. Presentation Date: Saturday, June 17, 2023

SAT551 Significantly Elevated Thyroglobulin Levels with Negative Whole-Body Scan and PET/CT After Treatment of Thyroid Cancer: A Case Report

Abstract Disclosure: A. Bassatne: None. J.T. Chaiban: None. Background: Thyroglobulin (Tg) levels are used to monitor recurrence or persistence of disease after treatment of differentiated thyroid cancer. Some cases may have persistently elevated Tg and negative whole-body scans (WBS). We present a case of substantially elevated Tg levels despite negative WBS and PET/CT after thyroidectomy and radioactive iodine (RAI) treatment in a patient with papillary thyroid carcinoma (PTC). Clinical Case: A 66 years old lady was referred to the endocrinology clinic almost 5 years ago after incidental findings of calcified thyroid nodules on CT. Thyroid US confirmed 2cm aggregate calcified nodules. FNA revealed PTC for which she underwent thyroidectomy. Pathology showed a unifocal 3.5 cm left lobe conventional PTC without angioinvasion nor extrathyroidal extension, 3/13 positive lymph nodes (LN) on the lateral dissection of the left neck as well as multiple small LN on the central dissection. 6 days postop, her Tg was still significantly high at 40.5ng/mL (Ref 1.2-35 ng/mL) and then increased to 397ng/mL after thyrogen preparation for RAI ablation, antithyroglobulin antibodies were negative. WBS post RAI was negative except for the physiologic neck uptake. Almost a year later, a diagnostic WBS after thyrogen stimulation was still negative but the stimulated Tg increased again to 235 ng/mL with negative thyroglobulin antibodies. Tg result were confirmed by LC-MS method. Heterophile Antibodies were negative. Patient confirmed that every single time she followed at least 2 weeks of low iodine diet in preparation for the WBS. Unfortunately, we were not able to get a 24 hour urine collection for iodine. A PET/CT was reassuring. CT neck/chest did not show any suspicious metastases. TSH was maintained at an adequately suppressed level all through and Tg levels were ranging around 6-8 ng/mL. After another year, a stimulated Tg was 302.4 ng/mL with a TSH of 198 mcU/mL (Ref 0.35-5.0 mcU/mL). At that time, a repeat WBS was negative and a repeat PET/CT demonstrated an interval development of a small thyroid focus thought to be consistent with recurrence of malignancy. However, a CT of neck/chest did not reveal any abnormal thyroid findings or metastases. Patient received 100 mCi of RAI after thyroid hormone withdrawal. Subsequent WBS was negative. Currently her Tg levels are stable at around 8-9ng/mL for the past 6 months with a suppressed TSH. Patient had another PET/CT through her breast surgeon to follow on a previous breast lesion and no thyroid abnormality was noted. Conclusion: Elevated Tg levels despite negative imaging may be seen in patients with PTC as illustrated in this case. We are reporting it due to the extent of elevation of Tg levels seen on more than one occasion in the absence of structural recurrence. Evaluation and treatment of such patients remain controversial. Presentation Date: Saturday, June 17, 2023

Low iodine diets prior to radioiodine treatment for thyroid cancer

Low iodine diets prior to radioiodine treatment for thyroid cancer

Postoperative Oral Iodine-131 Combined with Nutritional Management for the Management of Thyroid Cancer: A Meta-Analysis

Iodine nutrition plays a central role in the normal physiological function of the thyroid gland, and it is a major factor in thyroid hormone synthesis. A meta-analysis was used to measure the efficacy of oral iodine-131 combined with nutritional management in thyroid cancer patients after surgery. Computer searches were conducted on various databases, with the search time limited to January 2011 to December 2021, and the literature retrieved was limited to randomized controlled trials. Data extraction and quality evaluation were performed for the included literature, and meta-analysis was conducted by RevMan 5.3 software. A total of 9 literatures were obtained, all in English, with a sample size of 10,219 cases, containing 6,845 cases in the study group (oral iodine-131 + nutritional management) together with 3,374 cases in the control group (oral iodine-131 alone). The study group received oral administration of iodine-131 and nutritional management (low-iodine diet). The outcomes of the meta-analysis revealed that the clinical symptoms of thyroid cancer patients were improved after oral administration of iodine-131 after surgery. No statistical differences could be observed in the incidence of adverse reactions, recurrence rate, or metastasis rate of outcome indicators. To sum up, oral administration of iodine-131 combined with nutritional management has certain clinical effects in patients with thyroid cancer after surgery, but due to the limited literature included and low data quality, the conclusions of this study still need to be further verified.

Effects of a low-iodine diet in post-thyroidectomy thyroid cancer patients undergoing I131 therapy at the Vietnam National Cancer Hospital.

Background: I131 therapy is regarded as an "internal surgery" (i.e., a non-invasive approach involving no incision or bleeding) that supports "external surgery" (i.e., using a scalpel) in completely eradicating the root cause of thyroid cancer. Limiting iodine intake is of paramount importance in I131 therapy. I131 therapy protocols recommend that patients follow a low-iodine diet, ideally with a maximum iodine intake of 50 μg/day for two weeks before the I131 therapy. Methods: A pre-post compassion uncontrolled clinic intervention study was conducted on a group of over 70 post-thyroidectomy thyroid cancer patients with indications for I131 therapy at the Vietnam National Cancer Hospital from December 2020 to December 2022. Aim: It aimed to assess the effects of a low-iodine diet on post-thyroidectomy thyroid cancer patients with indications for I131 therapy. Results: The study found that following the intervention, the percentage of participants at risk of mild to moderate malnutrition, as assessed by the PG-SGA tool, decreased to 4.3% from 40.0% before the intervention, with a statistically significant difference of p < 0.001. There was a considerable improvement in the low calcemia level among the study participants, with 35.7% of patients experiencing hypocalcemia prior to the intervention, which reduced to 17.1% after the intervention. This difference was statistically significant (p = 0.01). The study also revealed a urinary iodine level improvement among the study participants. Before the intervention, patients' average urinary iodine level was 14.9 ± 11.3 µg/dl. Following the intervention, it reduced to 12.7 ± 3.9 µg/dl, although this difference was not statistically significant (p = 0.29). Patients' quality of life after adhering to the low-iodine diet tended to decline; however, the change in scores before and after the intervention did not show a significant difference. Conclusion: Despite its negative impact on patients' quality of life, active nutrition counseling and intervention during the low-iodine diet contributed to the substantial improvement in the hypocalcemia level and the reduced urinary iodine level among patients, which in turn could enhance the efficacy of the subsequent I131 therapy.

Efficiance of radioiodine remnant ablation in cases of locally differentiated thyroid cancer

On the territory of Russia has increased the of thyroid cancer after Chernobyl NPP incidence at 1986, and currently accounts for up to 14,000 newly identified cases. Postoperative radioiodine (RAI) remnant ablation is the second stage of combine treatment of differentiated thyroid cancer, except for the prevalence of pT1N0M0, with minimal level of TG and AT-TG, according to international guidelines. In the past 20 years a significant number of published practice guidelines for the treatment of this disease. However, the discussion is the amount of medication for administration activity (GBq) 131I, is required for successful ablation of thyroid remnants. The study analyzed 353 clinical cases after radical surgical treatment for DTC. In our study, the effectiveness of radioiodablation was compared with certain indicators of specific therapeutic activity 131I (MBq/kg), in groups of patients with different levels of TSH stimulation (less than 30 mME/ml, and more than 30 mME/ml). We evaluated the absorbed dose in the thyroid remnant in patients with residual thyroid tissue volume determined by US when administering 131I empirical therapeutic activity. The control of the WBS with 131I was carried out in 6 months. The average eղciency RAI was 85.5 %, there were no significant differences in the TSH stimulation groups of more than 30 mME/ml and 4-30 mME/ml (p &gt; 0.05). If the thyroid remnant is not detected by US, the effective range of 131I specific therapeutic activity is 30-40 MBq/ kg against a background of TTG stimulation greater than 4 ՏME/ml and strict adherence to a 14-day low iodine diet. Direct radiometry followed by neck scintigraphy (1200 kBq 131I) and calculation of therapeutic activity is recommended when determining thyroid remnant by US to plan for TAD = 300 Gy and reduce the risk of radiation sialoadenitis. At the time of RAI, 3.9 % of patients had previously undetectable X-rays lung metastases with stimulated TG levels greater than 124 ng/mL after surgical treatment with SPECT/CT.

Iodine, and selected goitrogens measured in some common grains from Sokoto zones, Nigeria

This study aimed to determine iodine, selected goitrogens in some grains in Sokoto. Related factors were measured in clay, loamy, and sandy soils using standard methods and reagents of analytical grade. Western zone (WZ) has highest iodine (29 ± 0.01 ppm), then Central Zone (CZ) (26 ± 0.01 ppm), and Eastern Zone (EZ) had (24 ± 0.01 ppm). Sandy soil had highest pH (6.55 ± 0.08), then clay (5.02 ± 0.06) and lastly loamy soil (4.02 ± 0.05). Organic matter was highest in clay (7.3±1.02%), loamy soil (6.0 ± 1.5%), and lastly sandy soil (6.0 ± 1.5%). Iodine in rice (25 ± 0.014ppm) was higher (P&lt;0.05) in WZ than (17±0.016 ppm) in EZ. Iodine in maize differed significantly (P &lt; 0.05) between WZ (28 ± 0.013 ppm) and EZ (20.0 ± 0.013 ppm). The difference (P &lt; 0.05) in iodine level of millet in WZ (18 ± 0.012 ppm) was higher than EZ (11 ± 0.014 ppm). In sorghum, iodine level between WZ (19 ± 0.010 ppm) and EZ (12 ± 0.012 ppm) differed significantly (P&lt;0.05). Goitrogens in studied grains are: 1.2 ± 0.04 to 8.7 ± 0.56ppm, 2.2 ± 0.04 to 5.8 ± 0.16ppm, 25 ± 0.34 to 48 ± 0.03ppm, and 30 ± 0.56 to 47 ± 0.53ppm for cyanogenic glycosides, glucosinolates, thiocyanate, and total polyphenols respectively. There was significant (p &lt; 0.05) iodine in grains of the state. However, goitrogens found in the grains could affect people that consume low-iodine diet or goitrogen laced-diet chronically.

The Efficacy of Low-Iodine Diet Instructional Media for the Preparation of Radioactive Iodine Therapy in Thyroid Patients

Objective: To develop and evaluate a low-iodine diet (LID) instructional media for preparing radioactive iodine (RAI) therapy on LID practices, and knowledge in thyroid patients. Material and Methods: This study was a randomized control trial (RCT), consisting of 120 thyroid participants; divided into 2 groups: a control group (original leaflet) and an intervention group (video and booklets). The efficacy of LID media was determined by measuring iodine intake, urine I/Cr ratio, knowledge tests, satisfaction surveys, and facilitators and barriers during the LID period. Results: This study was conducted with 96 individuals. The energy and biggest nutrient intake changes were significantly lower than the baseline. The iodine intake levels of the intervention group were significantly lower than those of the control group. Conversely, the urine I/Cr ratio and proportion of participants that achieved the criteria of both groups showed no significant difference via inter-group. Participants evaluated “agreed” and “strongly agreed” for satisfaction assessment. Furthermore, both groups suggested the importance of social support and encouragement to attain their goal. Conclusion: The results of the efficacy of LID instructional media were evidence-based for developing and evaluating LID multimedia for preparing RAI therapy in thyroid patients in Thailand. There are also good instruments for advice to thyroid patients in the hospital.

Novel Interactomes of Cardiac Noncoding RNA Transcriptome under Altered Thyroid Hormonal States

Background: Noncoding RNAs are emerging as key players in cardiovascular diseases. Both Hypothyroidism (HypoTH; low thyroid hormones [THs]) and hyperthyroidism (HyperTH; high THs) can be deleterious to the heart. We recently showed the involvement of long noncoding RNAs (lncRNAs) in HypoTH under caloric restriction. However, a comprehensive view of the cardiac transcriptome and its interactions under altered TH states is lacking. We hypothesized that cardiac noncoding interaction networks are significantly altered in the cardiac-TH regulatory axis. Methods: In this randomized, blinded study (2.5 mon), adult C57 mixed-sex mice (n=8-10/group; 5 females, 3-5 males) were divided into Control, HypoTH (low iodine diet with oral methimazole), HyperTH (1 microgram [ug]/gram Thyroxine, T4; intraperitoneal) and HypoTH+T3 (similar to HypoTH with oral 12 ug/kilogram/day Triiodothyronine, T3). Morphometrics, ultrasound, immunosorbent assay, Quantitative real-time PCR (qPCR) and whole transcriptome sequencing were performed. Statistical analyses were done by Tukey’s analysis of variance (with post hoc), Benjamini &amp; Hochberg and others using Prism, R, etc. RNA quality was validated by Nanodrop, gel electrophoresis and Bioanalyzer. Results: In mixed-sex mice, HypoTH showed significant cardiac atrophy (whole heart, LV and right ventricle), low serum total T3 and T4 levels (p&lt;0.001), low heart rate, (p&lt;0.01) diminished systolic LV posterior (p&lt;0.05) and septal wall thicknesses (p&lt;0.01) and fractional shortening (-34%; p&lt;0.01) compared to controls. T3 therapy showed feedback inhibition of T4 (p&lt;0.001) and restored all other parameters including LV systolic diameter (p&lt;0.05). Among others, HyperTH had cardiac hypertrophy and increased T3 and T4 (p&lt;0.05) compared to controls (p&lt;0.001). Similar significant results were obtained in males and females. qPCR of shorter-term treatment showed significantly altered lncRNAs in inflammatory and immune pathways. Whole transcriptome sequencing showed numerous differentially expressed, significantly altered and enriched ( GO and KEGG) targets across the groups among all RNA species studied (p-adjusted; padj&lt;0.05). These include novel and known lncRNAs, microRNAs (miRNAs) and messenger (m) RNAs that change in opposite directions in low vs high TH groups. These also include 11 novel circular RNAs (circRNAs; CIRI2) decreased with HyperTH (padj&lt;0.05). We also uncovered novel co-expression and interactions of miRNA-mRNA, miRNA-lncRNA, mRNA-lncRNA, circRNA-miRNA and miRNA-lncRNA-mRNA (including TH receptor alpha; miRanda, Cytoscape) and also splicing and base editing events (padj&lt;0.05). Conclusions: This is the first cross-disciplinary study reporting a comprehensive cardiac transcriptome-wide interactome network of circRNA, lncRNA, miRNA and mRNA in a TH-responsive manner. This offers significant translational potential to develop diadiagnostic and therapeutic targets for cardiac-endocrine co-morbid conditions. NYITCOM at A-State, ABI This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Low-iodine diet before radioactive iodine therapy - to prescribe or not to prescribe

Iodine is the most important trace element in the human body. Its main function is to participate in the synthesis of thyroid hormones, thyroxine (T4) and triiodothyronine (T3). The main source of iodine for humans is food rich in this trace element. The iodine content in foods varies greatly. The main sources of iodine are seafood, iodized salt, seaweed, as well as dairy products and egg yolks. In addition, iodine is found in a number of drugs for external and internal use, dietary supplements, and in iodinated contrast agents.Low-iodine diet (less than 50 μg per day) is prescribed before radioactive iodine therapy (RAIT) for thyroid diseases, namely hyperthyroidism and differentiated thyroid cancer. Currently, there is no consensus on the clinical benefits of such a diet, especially in countries with iodine deficiency, such as Russia.The aim of this review is to assess the need for a low-iodine diet and its optimal duration, as well as to determine the clinical characteristics affecting the outcome of RAIT, based on data from recent studies.

Measurements of elemental iodine in soy sauces in Taiwan using a modified microplate method.

Soy sauce is widely used in a variety of Asian dishes to enhance flavor. Soybean and most soybean products, including soy sauces, are listed as prohibited foods in a low iodine diet. However, the iodine content in soy sauces is largely unknown. The aim of this study was to determine the iodine content in domestic soy sauces in Taiwan. Twenty-five different kinds of soy sauces were diluted with distilled water and with a dilution factor of fifty or above. Iodine concentrations of the diluted samples were measured colourimetrically based on the Sandell-Kolthoff reaction by a modified microplate method. All the measurements were repeated twelve times on three different days for determination of mean and standard deviation (SD), and coefficients of variance (CV). Serial dilution and recovery tests were also performed for validation. The results were confirmed by an inductively coupled plasma mass spectrometry (ICP-MS) method. Among the twenty-five surveyed soy sauces, most of them (n=22) were iodine-free (<16 ug/L, and thus un-detectable). The iodine concentrations (mean ± SD) of the three iodine-containing soy sauces were 2.7 ± 0.1, 5.1 ± 0.2, and 10.8 ± 0.6 mg/L, respectively. The inter-assay, intra-assay and total CVs were all <5.3% for the modified microplate method. The results obtained by ICP-MS were consistent with those of the modified microplate method. The recovery rates in the serial dilution test and recovery test ranged from 94.7% to 118.6%. Two of the three iodine-containing soy sauces were supplemented with kelp extract, while the other one without kelp extract had the highest amount of salt among the three iodine-containing soy sauces. Therefore, we postulate that iodized salt instead of kelp extract is the source of higher iodine content in that sauce. The results suggest that most soy sauces are iodine-free and may be allowed during low iodine diets.