Selenium in the treatment of mild-to-moderate Graves' orbitopathy: a 5-year prospective controlled cohort study.

PURPOSE: Graves' orbitopathy (GO) is the main extrathyroidal manifestation of Graves' disease. However, limited studies have investigated the actual efficacy of selenium in GO therapy. This longitudinal study explored the effect of selenium on QOL and prognosis of patients with mild-to-moderate GO. METHODS: We conducted a 5-year prospective controlled cohort clinical trial to determine the effect of selenium on 74 patients with mild-to-moderate GO. Patients received selenium yeast or placebo orally for 6 months and were followed up at 6 months and at 5 years by biochemical examination, ophthalmologist evaluation and QOL questionnaire to assess oculopathy and QOL. RESULTS: (1) During a follow-up period of 3-6 months, in the selenium group, the symptoms of tearing, grittiness and conjunctival congestion improved (P < 0.01); clinical activity scores and total GO-QOL scores increased relative to baseline (P < 0.01); TRAb was decreased at the 6-month evaluation (P = 0.003); and patients treated with selenium had a higher rate of improvement and a lower rate of worsening than patients treated with placebo (P < 0.05). (2) Exploratory evaluations at 6 months after drug withdrawal confirmed the earlier results; further changes included alleviation of blurred vision and double vision symptoms in the selenium group (P < 0.01). (3) At the 5-year follow-up, compared with baseline, proptosis, clinical activity scores, TRAb level and total GO-QOL scores in both the selenium and placebo groups were significantly improved (P < 0.01). CONCLUSION: Six months of selenium supplementation may effectively change the early course of mild-to-moderate GO, but this regimen makes no difference in long-term outcomes.

Serum Trace Elements Profile in Graves' Disease Patients with or without Orbitopathy in Northeast China.

OBJECTIVE: The purpose of the present study was to investigate serum trace elements in Graves' disease (GD) patients with or without orbitopathy in Northeast China. METHODS: Patients with newly diagnosed Graves' disease (HyGD) (n = 66), GD patients with euthyroid status or subclinical thyroidism after treatment (EUGD) (n = 55), GO patients with euthyroid status or subclinical thyroidism after treatment (GO) (n = 57), and normal controls (NC) (n = 66) were enrolled in this study. Serum trace elements were measured with ICP-MS. RESULTS: Serum selenium (Se) levels in EUGD group (median: 7.53 µg/dL), HyGD group (median: 6.76 µg/dL), and GO group (median: 7.40 µg/dL) were significantly lower than those in NC group (median: 9.20 µg/dL, all P < 0.01). Serum copper (Cu) levels in GO group (median: 95.93 µg/dL) were significantly lower than those in the NC group (median: 113.59 µg/dL, P = 0.015). After being adjusted for multivariables, thyroid-specific antibodies grade was associated with low Se levels. Hyperthyroidism and thyroid-specific antibodies grade were associated with high Cu levels. In addition, orbitopathy was associated with low Cu levels. CONCLUSIONS: Thyroid autoimmunity was associated with low Se levels. Hyperthyroidism and thyroid autoimmunity may be associated with relatively high serum Cu levels. Alternatively, ophthalmopathy may be related to low serum Cu levels.

Phagocytosis Deficiency of Macrophages in NOD.H-2h4 Mice Accelerates the Severity of Iodine-Induced Autoimmune Thyroiditis.

Apoptosis occurs in many autoimmune diseases. Excess iodine induces thyrocyte apoptosis and increases the incidence and prevalence of autoimmune thyroiditis (AIT). However, the sequence of events between the appearance of thyrocyte apoptosis and the occurrence of thyroiditis remains uncharacterized. Furthermore, few studies have investigated the role of macrophage phagocytosis in the development of AIT. Therefore, we evaluated the relationship between apoptosis and inflammatory infiltration in NOD.H-2h4 mouse thyroids by comparing the sequence of events in tissue samples. We also investigated the role of macrophages by comparing macrophage phagocytosis function in BALB/c, C57BL/6, and NOD.H-2h4 mice treated with different levels of iodine. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays and thyroid inflammatory scores revealed that apoptosis (2 weeks) occurred before inflammatory infiltration (4 weeks). Phosphatidylserine (PS) expression on the extracellular surface of the cell membrane and double-stranded DNA fragments associated with apoptosis appeared at 2 and 8 weeks, respectively. Additionally, although apoptosis was enhanced in the thyroids of mice supplemented with excess iodine (0.05 ± 0.12 vs 1.63 ± 0.82% for BALB/c, 0.09 ± 0.14 vs 1.51 ± 0.34% for C57BL/6, and 0.07 ± 1.11 vs 4.72 ± 0.62% for NOD.H-2h4 mice), only NOD.H-2h4 mouse thyroids presented with inflammation. Furthermore, macrophages from NOD.H-2h4 mice (44.46 ± 1.79%) exhibited decreased phagocytotic activity relative to that in BALB/c (54.21 ± 4.58%) and C57BL/6 (58.96 ± 4.04%) mice. There were no differences in phagocytosis function between NOD.H-2h4 mice supplemented with excess iodine or left untreated (24.50 ± 2.66 vs 21.71 ± 1.79%, p = 0.06). In conclusion, deficiencies in the apoptosis clearance of macrophages in NOD.H-2h4 mice may constitute an early pathogenic mechanism in AIT that is not influenced by iodine intake.

Effects of Selenium Supplementation on Spontaneous Autoimmune Thyroiditis in NOD.H-2h4 Mice.

BACKGROUND: Recent clinical studies have demonstrated the suppressive effect of selenium (Se) treatment on serum thyroid-specific antibody titers in patients with autoimmune thyroiditis (AIT), but the mechanism underlying this process is not clear. The aim of the present study was to investigate the effects of selenium on the incidence and severity of AIT, titers of thyroid autoantibodies, and selenoprotein expression in thyroid in a spontaneous autoimmune thyroiditis (SAT) model. METHODS: NOD.H-2(h4) mice at four weeks of age were randomly divided into control, iodine supplement (SAT), and selenium supplement groups (SAT+Se). Mice were given 0.005% sodium iodide water for eight weeks to induce SAT and then 0.3 mg/L sodium selenite in drinking water for 8 weeks and 16 weeks. The severity of lymphocytic infiltration in the thyroid, serum thyroglobulin antibody (TgAb) titers, serum selenium concentration, expression of glutathione peroxidase-1 (GPx1), thioredoxin reductase-1 (Txnrd1), and peroxiredoxin 5 were measured. RESULTS: Serum selenium concentration significantly increased after selenium supplementation. Serum TgAb levels were significantly lower in the selenium group compared with the SAT group (p<0.05). The prevalence of thyroiditis and the degree of infiltration of lymphocytes decreased gradually over time in the group provided with selenium supplementation. The expression of GPx1 and Txnrd1 by Western blotting were found to be significantly higher in the SAT+Se group than in other groups (p<0.05). CONCLUSIONS: These results indicate that selenium treatment can increase the function of antioxidation by upregulating the expression of selenoproteins in the thyroid and have an inhibitory effect on TgAb titers, which may have an impact on AIT.

Selenium upregulates CD4(+)CD25(+) regulatory T cells in iodine-induced autoimmune thyroiditis model of NOD.H-2(h4) mice.

Selenium (Se) is required for thyroid hormone synthesis and metabolism. Se treatment reduces serum thyroidspecific antibody titers in patients with autoimmune thyroiditis (AIT), but the exact mechanism is not clear. We investigated the effects of Se treatment on CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg) in a iodine-induced autoimmune thyroiditis model. NOD.H-2(h4) mice were randomly divided into control, AIT untreated, and AIT with Se treatment groups. Mice were fed with 0.005% sodium iodine (NaI) water for 8 weeks to induce AIT. Se-treated mice received 0.3 mg/L sodium selenite in drinking water. The AIT mice had fewer Treg cells and reduced Foxp3 mRNA expression in splenocytes compared with the controls (p < 0.01). The percentage of Treg cells and expression of Foxp3 mRNA were increased by Se treatment (as compared with untreated AIT mice, p < 0.05). Mice that received Se supplementation also had lower serum thyroglobulin antibody (TgAb) titers and reduced lymphocytic infiltration in thyroids than untreated AIT mice. These data suggest that CD4(+)CD25(+) T cells play an important role in the development of AIT. Se supplementation may restore normal levels of CD4(+)CD25(+) T cells by up-regulating the expression of Foxp3 mRNA in mice with AIT.

Safe range of iodine intake levels: a comparative study of thyroid diseases in three women population cohorts with slightly different iodine intake levels.

Iodine excess may lead to thyroid diseases. Our previous 5-year prospective survey showed that the prevalence and incidence of hypothyroidism or autoimmune thyroiditis increased with iodine intake. The aim of the present study was to investigate the optimal range of iodine intake by comparing the prevalence of thyroid diseases in three areas with slightly different levels of iodine intake. In 2005, 778 unselected women subjects from three areas with different iodine intake levels were enrolled. Levels of serum thyroid hormones, thyroid autoantibodies, and urinary iodine were measured, and thyroid B ultrasounds were performed. Among the subjects with mildly deficient iodine intake, those with adequate intake, and those with more than adequate intake, the prevalence of clinical and subclinical hypothyroidism was 0, 1.13, and 2.84%, respectively (P = 0.014); that of thyroid goiter was 24.88, 5.65, and 11.37%, respectively (P < 0.001); that of serum thyrotropin values was1.01, 1.25, and 1.39 mIU/l, respectively; and that of serum thyrotropin/thyroglobulin ratio was 7.98, 6.84, and 5.11, respectively (P < 0.001). In conclusion, median urinary iodine 100~200 mug/l may reflect the safe range of iodine intake levels. Serum thyrotropin/thyroglobulin ratio might be a better index of evaluating iodine status.

Influence of iodine on the reference interval of TSH and the optimal interval of TSH: results of a follow-up study in areas with different iodine intakes.

OBJECTIVE: The aim of the present study was to evaluate whether the status of iodine nutrition influences the TSH concentration in a selected Chinese reference population according to the criteria proposed by National Academy of Clinical Biochemistry (NACB) and regular thyroid ultrasonography, to establish a new reference interval of TSH based on the wide variation of iodine nutrition in populations, and to identify an optimal interval of TSH by following up the cohort with normal TSH concentrations at baseline. DESIGN: The study was conducted in Panshan, Zhangwu and Huanghua, the regions with mildly deficient, more than adequate and excessive iodine intake, respectively. Of the 3761 unselected subjects who were enrolled at baseline, 2237 met the criteria for a reference population. Of 3048 subjects with normal serum TSH at baseline, 2727 (80.0%) participated in the 5-year follow-up study. TSH and thyroid autoantibodies in serum and iodine in urine were measured, and B-mode ultrasonography of the thyroid was performed. RESULTS: In the reference population, there was a urinary iodine-related increment of serum TSH levels (r = 0.21, P = 0.000), and the mean levels of TSH in Panshan, Zhangwu and Huanghua were 1.15, 1.28 and 1.93 mIU/l, respectively (P = 0.000), corresponding to the rising regional iodine intake. Based on the overall data, we obtained a reference interval of 0.3-4.8 mIU/l. TSH concentrations obtained in the follow-up study correlated well with those at baseline (r = 0.58, P = 0.000). A baseline serum TSH > 1.9 mIU/l was associated with an increased incidence of development of supranormal TSH and a baseline serum TSH < 1.0 mIU/l was associated with an increased incidence of subnormal TSH development. CONCLUSIONS: Iodine nutrition is an important factor associated with TSH concentration even in the rigorously selected reference population. Baseline TSH of 1.0-1.9 mIU/l is an optimal interval with the lowest incidence of abnormal TSH in 5 years.

Folic acid reduces chemokine MCP-1 release and expression in rats with hyperhomocystinemia.

OBJECTIVE: This study aimed to investigate the effects of folate on the monocyte chemoattractant protein-1 (MCP-1) expression and release in rats with hyperhomocystinemia induced by ingestion of excess methionine. METHODS AND RESULTS: Thirty male Sprague-Dawley rats (200+/-20 g) were randomly divided into three groups (n=10 for each group): control group (Control), high-homocystinemia (Hhcy) group, and folate treatment (FA) group. They were fed with a normal regular diet, enriched by 1.7% methionine plus 1.7% methionine and 0.006% folate for 45 days. Our study showed the following: (a) A high methionine diet for 45 days is sufficient to induce hyperhomocystinemia; folate supplementation to the rats fed the high-methionine diet prevented an elevation homocysteine (Hcy) levels in the blood (P<.01). (b) Compared with the Control group, the Hhcy group had elevated plasma levels of MCP-1, and Hcy was significantly correlated with MCP-1 (P<.05). (c) The protein and mRNA expression of MCP-1 in the aorta was higher in rats from the Hhcy group than in rats from the Control group. (d) Most important, after folic acid supplementation, the lowering of Hcy levels was accompanied by a marked reduction of MCP-1 expressed in aortae and released from plasma and peripheral blood mononuclear cells (PBMCs) stimulated by oxidized low-density lipoprotein (P<.05, P<.01). CONCLUSION: Folic acid supplementation not only can blunt the rise in Hcy and reduce MCP-1 released from both plasma and PBMCs of rats with hyperhomocystinemia but also can downgrade MCP-1 expression in the aorta of rats with hyperhomocystinemia.

Chronic iodine excess does not increase the incidence of hyperthyroidism: a prospective community-based epidemiological survey in China.

OBJECTIVE: An increasing incidence of hyperthyroidism has been observed when iodine supplementation has been introduced to an iodine-deficient population. Moreover, the influence of chronic more than adequate or excessive iodine intake on the epidemiological features of hyperthyroidism has not been widely and thoroughly described. To investigate the influences of different iodine intake levels on the incidence of hyperthyroidism, we conducted a prospective community-based survey in three communities with mild-deficient, more than adequate (previously mild deficient iodine intake), and excessive iodine intake. SUBJECTS AND METHODS: In three rural Chinese communities, a total of 3761 unselected inhabitants aged above 13 years participated in the original investigation and 3018 of them received identical examinations after 5 years. Thyroid function, levels of thyroid peroxidase antibody (TPOAb), thyroglobulin antibody and urinary iodine excretion were measured and thyroid ultrasound examination was also performed. RESULTS: In three communities, median urinary iodine excretion was 88, 214, and 634 microg/l (P<0.05) respectively. The cumulative incidence of hyperthyroidism was 1.4, 0.9, and 0.8% (P>0.05) respectively. Autoimmune hyperthyroidism was predominant in thyroid hyperfunction in all the three cohorts. Either positive TPOAb (>50 U/ml) or goiter in original healthy participants was associated with the occurrence of unsuspected hyperthyroidism in 5 years (logistic regression, OR=4.2 (95% CI 1.7-8.8) for positive TPOAb, OR=3.1 (95% CI 1.4-6.8) for goiter). CONCLUSION: Iodine supplementation may not induce an increase in hyperthyroidism in a previously mildly iodine-deficient population. Chronic iodine excess does not apparently increase the risk of autoimmune hyperthyroidism, suggesting that excessive iodine intake may not be an environmental factor involved in the occurrence of autoimmune hyperthyroidism.

Folic acid reduces adhesion molecules VCAM-1 expession in aortic of rats with hyperhomocysteinemia.

To investigate effects of supplementation of folic acid on the expression of adhesion molecules VCAM-1 in the aortas of rats with hyperhomocysteinemia. Thirty male SD rats (200 +/- 20 g) were invided into 3 groups (n = 10 for each group): control group(Control), high Met group(Met) and Met plus Folate group(Met + Folate), fed. for 45 days. Plasma Hcy levels were higher with the high-methionine diet (140.68 +/- 36.87 micromol/L vs 6.47 +/- 1.10 micromol/L in control rats) an effect which was reduced by folate. Respectively, the aortic expression of adhesion molecules VCAM-1 at protein and mRNA levels were higher in the Met groups than those in the control groups or the Met + Folate groups. A high methionine diet for 45 days was sufficient to induce hyperhomocysteinemia. Folate supplementation prevented elevation of Hcy levels in the blood, and reduced expression of the adhesion molecule VCAM-1. Hyperhomocysteinemia is now regarded as one of the important risk factors for cardiovascular and cerebralvascular disorders.[Welch GN, Loscalzo J. Homocysteine and atherothrombosis. N Engl J Med 1998; 38(15):1042-50.] Several plausible mechanisms for Hcy-induecd atherosclerosis have been proposed. These include endothelial dysfunction, enhancement of oxidative stress, reduction in NO bioavailability, and augmentation of thrombus formation.[Holven KB, Holm T, Aukrust P, et al. Effect of folic acid treatment on endothelium-dependent vasodilation and nitric oxide-derived end products in hyperhomocysteinemic subjects . Am J Med 2001;110(7):536-42; Guba SC, Fonseca V, Fink LM. Hyperhomocysteinemia and thrombosis. Semin Thromb Hemost 1999;25(3):291-309.] However, the precise molecular mechanism is still unclear. Recent reports have suggested a role for inflammatory processes in the pathogenesis of atherosclerosis.[Gerard C, Rollins BJ. Chemokines and disease. Nat Immunol 2001;2(2):108-15.] Dysfunction of endothelial cells is the key process promoting inflammatory reactions. On injury, endothlial cells are capable of producing various cytokines that participate in inflammatory reactions in the arterial wall. Although results from in vitro studies suggest that Hcy, at pathophysiological concentrations, stimulates chemokine expression in vascular cells, it is unknown whether hyperhomocysteinemia can initiate similar changes, leading to enhanced momocyte adhesion/binding to the vascular endothelium in vivo.[Zeng X, Dai J, Remick DG, Wang X. Homocysteine mediated expression and secretion of monocyte chemoattractant protein-1 and interleukin-8 in human monocytes. Circ Res 2003;93(4):311-20.] On the basis of the potential pathogenic role of chemokines in atherogenesis, the objective of the present study was to investigate that homocsteine may exert its effect in part though adhesion molecules VCAM-1 and that folic acid supplementation may downregulate these inflammatory responses. Male Sprague-Dawley rats (bred from animal centers of Tongji Medical College, Huazhong Science and Technology University) aged 8 weeks were divided into 3 groups(n=10 for each group) and maintained for 45 days on the following diets before the experiments: (1) regular diet; (2) high-metheionine diet, consisting of regular diet plus 1.7% methionine; and (3) high-methionine plus folate -rich diet, consisting of regular diet plus 1.7% methionine and 0.006% folate.[Boisvert WA, Curtiss LK, Terkeltaub RA. Interleukin-8 and its receptor CXCR2 in atherosclerosis. Immunol Res 2000;21(2-3):129-d37.] Plasma and serum samples wee colleced and stored at -80 degrees C after 45 days until analysis. The plasma homocysteine concentration of rats in three groups were determined by high-pressue liquid chromatography. To detect the endothelial expression of adhesion molecules VCAM-1, the thoracic aorta was isolated and dived into segments. These segments were immersion-fixed in 10% neutral-buffered formalin overlight and then embedded in paraffin. Sequential 5 mum paraffin-embedded cross sections were prepared. Immunohistochemical analyisis was performed to detect vascular cell adhesion molecule(VCAM)-1, The fixed cryosections were immediately blcked in 10% horse serum and phosphate baffered saline(PBS) at room temperature for 30 min. Goat polyclonal andibodies against rat VCAM-1(Santa Cruz Biotechnology) were diluted 1:100 in PBS and incubated with the cryosections for 1 h of room temperature. After three washes, the sections were incubated with biotin-conjugated rabbit anti-goat immunoglobulins(Dako) at 1:250 dilution in PBS. After three washes, the samples were mounted in 90% glycerol-PBS. Photographs were taken by use of a light microscope at a mignification of x200.

[An epidemiological study on the relationship between selenium and thyroid function in areas with different iodine intake].

OBJECTIVE: To investigate the relationship between selenium status and thyroid dysfunction in 3 areas with different iodine intake. METHODS: An epidemiological research was performed in the rural communities of Panshan County (iodine-deficient area) and Zhangwu County (iodine-sufficient area), Liaoning Province, and Huanghua County, Hebei Province (iodine-excessive area). Serum selenium, TSH, FT3 and FT4 levels were examined in 329 patients with thyroid dysfunction (including clinical hypothyroidism, subclinical hypothyroidism, clinical hyperthyroidism and subclinical hyperthyroidism) and 183 normal inhabitants. RESULTS: The median serum selenium concentrations in Panshan, Zhangwu and Huanghua were 91.4, 89.1, and 83.2 microg/L respectively. There was no difference in serum selenium levels between the patients with subclinical hypothyroidism, clinical hypothyroidism, and clinical hyperthyroidism and their normal controls. The median serum selenium concentration of the subclinical hyperthyroidism patients was 82.6 microg/L, significantly lower than that of the normal controls (87.3 microg/L). The FT3/FT4 ratio was decreased, the FT4 level was increased in the subclinical hyperthyroidism patients in comparison with the normal controls, and no significant difference in FT3 level was found between them. No significant effect of sex and age was found on serum selenium level of normal inhabitants. In normal controls serum selenium was inversely correlated with serum TSH level, and the subjects with serum selenium < or = 80 microg/L had the median TSH level of 2.10 mU/L, markedly higher than that of the subjects with the serum selenium of 80-100 microg/L (1.29 mU/L) and that of the subjects with the serum selenium of 100 approximately 120 micro g/L (1.28 mU/L). For the thyroid dysfunction patients with positive thyroid auto-antibody (TPOAb) in Zhangwu County, the serum selenium was negatively associated with TPOAb level. The serum selenium level of the TPOAb highly positive group (TPOAb > 600 IU/ml) was 83.6 IU/ml, significantly lower than those of the TPOAb lowly positive group and TPOAb moderately positive group (83.6, 92.9 and 95.6 microg/L respectively). CONCLUSION: No obvious effect of selenium status is found on the development of thyroid dysfunction in these three areas. But selenium deficiency can impair thyroid function by means of disturbing thyroid hormone metabolism and decreasing antioxidant ability of the thyroid.