Iodine nutrition optimization: are there risks for thyroid autoimmunity?

Iodine deficiency is still the main cause of preventable thyroid disorders, worldwide. To optimize iodine intake, programs of voluntary or mandatory iodization of salt have been implemented in several iodine-deficient countries and iodine sufficiency has been achieved in many. Despite the clear beneficial effects on thyroid health, some concerns have been raised on the presumed detriment of iodine prophylaxis on thyroid autoimmunity. Very recent studies aimed at evaluating the long-term consequences of iodine supplementation on thyroid autoimmunity and related dysfunction, have clearly demonstrated that the early post-iodization increase in thyroid antibody positivity is largely transient and not clinically relevant, since the prevalence of overt thyroid dysfunction has remained reassuring low over two decades. The recommended iodine intake is therefore safe with regard to thyroid autoimmunity, the benefits largely outweighing the risks in a population with a stable median iodine concentration not exceeding 300 µg/L. Thus, a possible increase in thyroid autoimmunity should not represent a limitation to promoting iodine supplementation in the general population, also taking into account the steady rise in prevalence of autoimmune disorders which has occurred in the last few decades because of environmental factors other than iodine.

Serum levels of advanced glycation end products (AGEs) are increased and their soluble receptor (sRAGE) reduced in Hashimoto's thyroiditis.

PURPOSE: Advanced glycation end products (AGEs) are increased in conditions of oxidative stress and promote inflammation by interacting with their receptor RAGE on cell membrane. By contrast, the soluble receptor sRAGE exerts protective effects by competing with RAGE for ligand binding. AGEs/sRAGEs interaction is involved in the pathogenesis of several diseases related to oxidative stress. In the present study, we evaluated the AGEs/sRAGEs oxidative balance in Hashimoto' thyroiditis (HT). METHODS: We measured the levels of sRAGE, by ELISA, and AGEs, by spectrophotometric method, in the serum of 50 HT patients (5 M, 45 F; mean age 38.5 ± 12 years) and 50 age-, sex- and BMI-matched healthy controls. All subjects were euthyroid at recruitment and none was on LT-4 therapy. RESULTS: Serum sRAGEs were significantly lower (median 424 vs 738 pg/ml; p = 0.001) and AGEs higher (205 vs 114 AU/g prot; p = 0.001) in HT patients compared to controls, and the two parameters were inversely correlated (p = 0.016). Accordingly, the AGEs/sRAGEs ratio was threefold higher in HT patients than controls (0.48 vs 0.15; p = 0.0001). In regression analysis models, serum TPO-Ab were the main predictors for AGEs and sRAGEs levels and AGEs/sRAGEs ratio (p < 0.0001), irrespective of TSH and/or FT4 values. CONCLUSION: sRAGEs were decreased and AGEs increased, suggesting a dysregulation of AGE/sRAGEs-related oxidative homeostasis in HT patients, even when in euthyroid status. Autoimmunity per se seems to play an important role in AGEs/sRAGE imbalance, irrespective of thyroid function alterations.

Non-specific rheumatic manifestations in patients with Hashimoto's thyroiditis: a pilot cross-sectional study.

PURPOSE: Hashimoto's thyroiditis (HT) is often associated with rheumatic disorders (arthritis, etc.), but many HT patients report non-specific rheumatic signs and symptoms in the absence of clinically evident rheumatic diseases. Aim of this study was to evaluate the prevalence of non-specific rheumatic manifestations (RMs) in HT subjects without classified autoimmune comorbidities. METHODS: 500 HT patients (467 F, 33 M; median age 41 years, range 14-69) and 310 age- and sex-matched controls, consecutively referred to the Endocrine Unit of Messina University Hospital, were evaluated for non-specific RMs. None took L-thyroxine. EXCLUSION CRITERIA: autoimmune comorbidities, infectious, and/or inflammatory diseases, history of neoplasia, BMI > 30 kg/m2. RESULTS: In our HT cohort, 100 patients (20%) complained of one or more RMs, vs 21 controls (6.8%; P < 0.001). There were minimal differences between the manifestations recorded in the two groups, the most common being polyarthralgias and myalgias/fibromyalgia, but non-specific RMs occurred threefold more in HT patients. Comparing HT patients with RMs (96 F and 4 M) with those affected by HT alone, female sex was prevalent (F:M ratio 24:1 vs 5:1) with higher age at diagnosis (median 43 vs 37 years; P < 0.001). HT patients with RMs (62%) were mostly euthyroid (median TSH 2.0 µIU/L) and only 7% overtly hypothyroid, discouraging a possible causal relationship between thyroid dysfunction per se and RMs. CONCLUSIONS: A significant percentage of HT patients complains of non-specific rheumatic signs and symptoms, in the absence of other diagnosed systemic comorbidities and regardless of thyroid functional status, deserving careful evaluation and prolonged follow-up.

The interplay between thyroid and liver: implications for clinical practice.

A complex relationship exists between thyroid and liver in health and disease. Liver plays an essential physiological role in thyroid hormone activation and inactivation, transport, and metabolism. Conversely, thyroid hormones affect activities of hepatocytes and hepatic metabolism. Serum liver enzyme abnormalities observed in hypothyroidism may be related to impaired lipid metabolism, hepatic steatosis or hypothyroidism-induced myopathy. Severe hypothyroidism may have biochemical and clinical features, such as hyperammonemia and ascites, mimicking those of liver failure. Liver function tests are frequently abnormal also in hyperthyroidism, due to oxidative stress, cholestasis, or enhanced osteoblastic activity. Antithyroid drug-associated hepatotoxicity is a rare event, likely related mainly to an idiosyncratic mechanism, ranging from a mild hepatocellular damage to liver failure. Propylthiouracil-induced liver damage is usually more severe than that caused by methimazole. On the other hand, thyroid abnormalities can be found in liver diseases, such as chronic hepatitis C, liver cirrhosis, hepatocellular carcinoma, and cholangiocarcinoma. In particular, autoimmune thyroid diseases are frequently found in patients with hepatitis C virus infection. These patients, especially if thyroid autoimmunity preexists, are at risk of hypothyroidism or, less frequently, thyrotoxicosis, during and after treatment with interpheron-alpha alone or in combination with ribavirin, commonly used before the introduction of new antiviral drugs. The present review summarizes both liver abnormalities related to thyroid disorders and their treatment, and thyroid abnormalities related to liver diseases and their treatment.

Endocrine and metabolic adverse effects of immune checkpoint inhibitors: an overview (what endocrinologists should know).

Immune checkpoint inhibitors (ICIs) are novel anticancer agents, recently introduced with the aim of boosting the immune response against tumors. ICIs are monoclonal autoantibodies that specifically target inhibitory receptors on T cells: cytotoxic T lymphocyte antigen 4 (CTLA4), programmed death 1 (PD-1) and its ligand (PD-1L). ICIs also generate peculiar dysimmune toxicities, called immune-related adverse events (irAEs), that can potentially affect any tissue, and some may be life-threatening if not promptly recognized. The endocrine and metabolic side effects of ICIs are reviewed here, with a particular focus on their clinical presentation and management. They are among the most frequent toxicities (around 10%) and include hypophysitis, thyroid disorders, adrenalitis, and diabetes mellitus. Treatment is based on the replacement of specific hormone deficits, accompanied by immunosuppression (with corticosteroids or other drugs), depending on irAEs grade, often without the need of ICI withdrawal, except in more severe forms. Prompt recognition of endocrine and metabolic irAEs and adequate treatment allow the patients to continue a therapy they are benefiting from. Endocrinologists, as an integral part of the multidisciplinary oncologic team, need to be familiar with the unique toxicity profile of these anticancer agents. Practical recommendations for their management are proposed.

Increased serum interleukin-37 (IL-37) levels correlate with oxidative stress parameters in Hashimoto's thyroiditis.

PURPOSE: Interleukin-37 (IL-37), member of the IL-1 family, is a natural suppressor of immune and inflammatory responses. Increased serum IL-37 levels were observed in several autoimmune diseases, including Graves' disease. To our knowledge, no data on Hashimoto's thyroiditis (HT) are available in the literature. METHODS: Aim of our study was to measure serum IL-37 levels and evaluate their relationship, if any, with oxidative stress markers in HT patients. We enrolled 45 euthyroid HT patients (5 M e 40 F, median age 40 years) and 50 age- and sex-matched healthy controls. None was under L-thyroxine therapy. Serum IL-37 levels were measured by ELISA. Specific serum tests, such as derived reactive oxygen metabolites (d-ROMs), and biological anti-oxidant potential (BAP) test were performed in all subjects to investigate the changes in oxidative balance, and advanced glycation end products (AGEs) were determined as a specific marker of oxidative stress. RESULTS: IL-37 levels were significantly higher in HT than in controls (median 475 vs. 268 pg/ml, P = 0.018). In the same patients, serum oxidants (d-ROMs) were increased and anti-oxidants (BAP) decreased compared with controls (P = 0.011 and < 0.0001, respectively), clearly indicating an enhanced oxidative stress. In addition, AGEs levels were higher in HT patients than in controls (210 vs. 140 AU/g prot, P < 0.0001) and directly correlated with IL-37 levels (P = 0.048). At multivariate analysis, the main independent predictors that influenced IL-37 levels were both anti-thyroid antibodies (P = 0.026) and AGEs levels (P = 0.001). CONCLUSIONS: IL-37 is up-regulated in HT and may exert a protective role by counteracting oxidative stress and inflammation.

Combined BRAFV600E analysis and 99mTc-MIBI scintigraphy can be a useful diagnostic tool in differentiated thyroid cancer patients with incomplete bio-chemical response to first radioiodine therapy (RAIT): a pilot investigation.

PURPOSE: The aim of the present study was to evaluate the possible diagnostic role of the combined performance of BRAF mutation analysis and MIBI scintigraphy in papillary thyroid cancer (PTC) patients with incomplete bio-chemical response to first radioiodine therapy (RAIT) performed for thyroid remnant ablation. METHODS: The records of 15 PTC patients with bio-chemical incomplete response to first RAIT were retrospectively analyzed. BRAFV600E analysis on primary tumor samples was obtained in all cases along with neck ultrasonography and 99mTc-MIBI scintigraphy of the neck-thorax regions at first follow-up. All patients then underwent RAIT with high radioiodine activities. A post-therapy whole-body scan (pT-WBS) was acquired 5-7 days after RAIT. RESULTS: Abnormal radioiodine uptake was found in 10 out of the 15 patients (67%, 131I+ve), while in the remaining 33%, no abnormal radioiodine uptake was detected (5/15, 131I-ve). Abnormal tracer uptake was found in 6 out of 10 131I+ve patients at 99mTc-MIBI scintigraphy (MIBI+ve). BRAFV600E mutation was not found in the majority of 131I+ve patients (9 out of 10 BRAFV600E-ve). On the contrary, in the 5 131I-ve patients, 99mTc-MIBI scintigraphy did not show any abnormal tracer uptake (MIBI-ve), while BRAFV600E mutation was present (BRAFV600E+ve). Thus, in our series, the association between MIBI-ve scintigraphy and BRAF+ve mutation was a useful diagnostic tool in predicting negative pT-WBS outcome. CONCLUSION: Albeit obtained in a small retrospective series, our results suggest that the combination of BRAFV600E+ve mutation and MIBI-ve scintigraphy may be considered a negative prognostic clue, which predicts the absence of radioiodine uptake at pT-WBS in DTC patients with incomplete bio-chemical response to first RAIT.

Correlation of cardio-metabolic parameters with vitamin D status in healthy premenopausal women.

PURPOSE: Vitamin D has been associated with metabolic disorders and increasing risk of cardiovascular diseases, with conflicting results. Aim of our study was to evaluate the relationship, if any, between cardio-metabolic risk factors and serum 25(OH)D concentrations in healthy women in premenopausal age. METHODS: We enrolled 200 healthy women, aged 19-50 years (mean age ± SD, 38 ± 11 years). In each subject, we measured serum 25(OH)D in relation to metabolic biomarkers and cardiovascular parameters. RESULTS: A status of vitamin D deficiency was found in 48% of the study population, while 38% showed levels higher than 30 ng/ml. Fasting glucose and insulin levels were significantly higher in subjects with vitamin D deficiency/insufficiency (P = 0.034 and P = 0.049, respectively) as well as HOMA-IR (P = 0.05). HDL cholesterol was significantly lower (P = 0.024) and intima-media thickness (IMT) higher (P = 0.014) in the vitamin D deficient/insufficient subjects. Moreover, serum 25(OH)D levels inversely correlated with insulin levels (P = 0.0001) and intima-media thickness (P = 0.015), and directly with serum HDL cholesterol (P = 0.010). At univariate regression analysis, the parameters that were significantly associated with vitamin D levels were insulin (P = 0.050), HDL cholesterol (P = 0.016), and intima-media thickness (P = 0.015). At multivariate analysis adjusted for age and BMI, vitamin D was still significantly associated with HDL cholesterol and intima-media thickness. CONCLUSIONS: A positive association between vitamin D and HDL cholesterol was found in healthy women without any evidence of metabolic disorders, with a significant inverse correlation between vitamin D and IMT. These results suggest a possible protective role of 25(OH)D in cardiovascular disorders.

Gly972Arg of IRS-1 and Lys121Gln of PC-1 polymorphisms act in opposite way in polycystic ovary syndrome.

PURPOSE: Polycystic ovary syndrome (PCOS) was associated with a number of polymorphisms of genes involved in insulin signaling. So far, they have been studied separately. The aim of this study was to verify the impact of the coexistence of two polymorphisms of insulin signaling. METHODS: One hundred consecutive PCOS women (diagnosed by Rotterdam criteria) and 45 age-matched healthy women were genotyped for two polymorphisms: Gly972Arg of IRS-1 and Lys121Gln of PC-1. Also, they underwent clinical evaluation, blood sampling for measurement of metabolic and hormonal indices, and a 75-g oral glucose tolerance test (OGTT). RESULTS: Comparing PCOS women with controls, the rate of homo-/heterozygosity was significantly greater (50 vs. 24.5%, P = 0.004) for IRS-1 polymorphism, but insignificantly greater (20 vs. 13.3%, P = 0.33) for PC-1 polymorphism. In PCOS women, compared with controls, the genotypes IRS-1 hetero/PC-1 wild type (WT) (36 vs. 17.8%, P = 0.03) and IRS-1 hetero/PC-1 hetero (14 vs. 6.7%, P = 0.20) were overrepresented at the expense of IRS-1 WT/PC-1 WT (44 vs. 68.8%, P = 0.005), while IRS-1 WT/PC-1 hetero was similarly represented (6 vs. 6.7%). Based on genotype, metabolic and hormonal indices changed significantly. For instance, six indices (HOMA-IR, fasting insulin, insulin area under the curve at OGTT, triglycerides, total and calculated free testosterone) were the highest in IRS-1 hetero/PC-1 WT women. CONCLUSIONS: Genetic variations in insulin signaling contribute to the extent and the variability of metabolic and hormonal derangement.

Hypopituitarism in the elderly: a narrative review on clinical management of hypothalamic-pituitary-gonadal, hypothalamic-pituitary-thyroid and hypothalamic-pituitary-adrenal axes dysfunction.

Hypopituitarism is an uncommon and under-investigated endocrine disorder in old age since signs and symptoms are unspecific and, at least in part, can be attributed to the physiological effects of aging and related co-morbidities. Clinical presentation is often insidious being characterized by non-specific manifestations, such as weight gain, fatigue, low muscle strength, bradipsychism, hypotension or intolerance to cold. In these circumstances, hypopituitarism is a rarely life-threatening condition, but evolution may be more dramatic as a result of pituitary apoplexy, or when a serious condition of adrenal insufficiency suddenly occurs. Clinical presentation depends on the effects that each pituitary deficit can cause, and on their mutual relationship, but also, inevitably, it depends on the severity and duration of the deficit itself, as well as on the general condition of the patient. Indeed, indications and methods of hormone replacement therapy must include the need to normalize the endocrine profile without contributing to the worsening of intercurrent diseases, such as those of glucose and bone metabolism, and the cardiovascular system, or to the increasing cancer risk. Hormonal requirements of elderly patients are reduced compared to young adults, but a prompt diagnosis and appropriate treatment of pituitary deficiencies are strongly recommended, also in this age range.