Different Levels Of Iodine Research Articles

Effects of different iodine levels on the DNA methylation of intrinsic apoptosis-associated genes and analysis of gene-environment interactions in patients with autoimmune thyroiditis.

Iodine is an essential nutrient that may change the occurrence of autoimmune thyroiditis (AIT). Apoptosis and DNA methylation participate in the pathogenesis and destructive mechanism of AIT. We detected the methylation and the expression of mRNA of intrinsic apoptosis-associated genes (YWHAG, ING4, BRSK2 and GJA1) to identify the potential interactions between the levels of methylation in these genes and different levels of iodine. 176 adult patients with AIT in Shandong Province, China, were included. The MethylTargetTM assay was used to verify the levels of methylation. We used PCR to detect the mRNA levels of the candidate genes. Interactions between methylation levels of the candidate genes and iodine levels were evaluated with multiplicative and addictive interaction models and GMDR. In the AIT group, YWHAG_1 and six CpG sites and BRSK2_1 and eight CpG sites were hypermethylated, whereas ING4_1 and one CpG site were hypomethylated. A negative correlation was found between methylation levels of YWHAG and mRNA expression. The combination of iodine fortification, YWHAG_1 hypermethylation and BRSK2_1 hypermethylation was significantly associated with elevated AIT risk. A four-locus model (YWHAG_1 × ING4_1 × BRSK2_1 × iodine level) was found to be the best model of the gene-environment interactions. We identified abnormal changes in the methylation status of YWHAG, ING4 and BRSK2 in patients with AIT in different iodine levels. Iodine fortification not only affected the methylation levels of YWHAG and BRSK2 but also interacted with the methylation levels of these genes and may ultimately increase the risk of AIT.

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 (2weeks) occurred before inflammatory infiltration (4weeks). Phosphatidylserine (PS) expression on the extracellular surface of the cell membrane and double-stranded DNA fragments associated with apoptosis appeared at 2 and 8weeks, 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.

Studies on Feeding Effect of Different Levels of Iodine in Salts at Consumption Level

A prospective cohort study was undertaken to determine the optimum level of iodine in salts at household level which is best suitable to fulfill daily requirements and not excrete too much iodine in urine. A total number of 99 households of 3rd categories and 4th categories employees of Dhaka University, Bangladesh, living in university campus, were randomly divided into 3 groups. A total 778 causal urine samples from 351 individuals of the total households were collected and urinary iodine was estimated by the wet digestion method adapted by Gutekunst et.al. to determine the feeding effect of different levels of iodine in salts. The overall median urinary iodine were 202.7, 196.9 and 238.0 µg/l during baseline study and baseline consumption pattern showed that mean iodine content of salts were 41.6, 34.1 and 36.9 ppm in group-1, group-2 and group-3 respectively. The first follow-up results showed that the overall median urinary iodine were 92.9, 165.2 and 265.6 µg/l and at that time their average iodine content of the experimental salts were 17.5, 27.5 and 45 ppm in group-1, group-2 and group-3 respectively. During first follow-up the majority (72.7%) of the selected population were biochemically iodine deficient in group-1 whereas, almost all (99.1 %) were normal in group-2 and a remarkable fraction of the population (37.9%) excreted excessive urinary ' iodine in group-3. The second follow-up findings indicates the overall median urinary iodine were 156.5, 169.3 and 180.3 µg/l in group-1, group-2 and group-3 respectively and at that time their experimental salt contained same amount of iodine (25-30 ppm). Iodine nutriture status of the study subjects during second follow-up revealed that almost all subjects (97.3%) were normal in group-!, on the other hand, biochemically deficient or excessive excretion of urinary iodine was not observed in group-2 and group-3 i.e. all of the subjects were within the normal range (UI 100-299.99 µg/l) of urinary iodine excretion.

The Standard, Intervention Measures and Health Risk for High Water Iodine Areas

Our study aims to clarify the population nutrient status in locations with different levels of iodine in the water in China; to choose effective measurements of water improvement(finding other drinking water source of iodine not excess) or non-iodised salt supply or combinations thereof; to classify the areas of elevated water iodine levels and the areas with endemic goiter; and to evaluate the risk factors of water iodine excess on pregnant women, lactating women and the overall population of women. From Henan, Hebei, Shandong and Shanxi province of China, for each of 50∼99 µg/L, 100∼149 µg/L, 150∼299 µg/L, and ≥300 µg/L water iodine level, three villages were selected respectively. Students of 6–12 years old and pregnant were sampled from villages of each water-iodine level of each province, excluded iodized salt consumer. Then the children's goiter volume, the children and pregnant's urinary iodine and water iodine were tested. In addition, blood samples were collected from pregnant women, lactating women and other women of reproductive age for each water iodine level in the Shanxi Province for thyroid function tests. These indicators should be matched for each person. When the water iodine exceeds 100 µg/L; the iodine nutrient of children are iodine excessive, and are adequate or more than adequate for the pregnant women. It is reasonable to define elevated water iodine areas as locations where the water iodine levels exceed 100 µg/L. The supply of non-iodised salt alone cannot ensure adequate iodine nutrition of the residents, and water improvement must be adopted, as well. Iodine excess increases the risk of certain thyroid diseases in women from one- to eightfold.

Iodine concentration in drinking water sources of selected villages in Ramtek Tehsil, Nagpur district, Maharashtra, India

Purpose – Iodine content in drinking water is a reflection of the iodine level of rocks and soil of the region. Different water sources have different levels of iodine; this makes variability in concentration of iodine content. The present study was done to estimate the iodine content in drinking water from different water sources of Ramtek villages in Nagpur district identified with sporadic cases of endemic goiter. The paper aims to discuss these issues. Design/methodology/approach – The water samples were collected from seven villages from Ramtek taluka, which included well, bore well and tap water. Water was collected in clean and dry glass bottles from each source from the entire villages under study. The analysis of the water samples was done by the method of Karmarkar et al. Findings – Iodine content of water samples varied from 17.42 to 43.55 μg/l in tap water, 17.42-21.77 μg/l in well water and 8.7-37.02 μg/l bore well water. The mean iodine content was found to be highest (34.04±11.44 μg/l) in tap water, while bore well water and well water showed 20.46±14.16 μg/l and 19.59±3.07 μg/l, respectively. Originality/value – The endemic area has been surveyed by the author – the data generated and analyzed – the findings of which are independently arrived. The study is helpful for students, academicians, independent researchers, and the government policy makers for their further research, policy formulation and implementation.

Changes of Sodium Iodide Symporter Regulated by IGF-I and TGF-β1 in Mammary Gland Cells from Lactating Mice at Different Iodine Levels

The sodium/iodide symporter (SLC5A5, also known as NIS) is a transmembrane glycoprotein. Physiologically, iodide transportation in the mammary gland occurs during late pregnancy and lactation. To identify factors that may regulate this process at different iodine levels, we have studied the expression of NIS gene and protein in cultured mammary gland explants from lactating mice by real-time quantitative PCR and In-Cell Western methods. Mammary gland cells were grown in media with different levels of iodine for 24h. The iodine treatment groups consist of low iodine group I (LI-I, 0μg/l), low iodine group II (LI-II, 5μg/l), control group (C, 50μg/l), high iodine group I (HI-I, 3,000μg/l), and high iodine group II (HI-II, 10,000μg/l). The cells were then incubated with or without insulin-like growth factor I (IGF-I) or transforming growth factor β1 (TGF-β1) for another 24h. We found that iodine inhibited NIS mRNA and protein expression in a dose-dependent manner. IGF-I and TGF-β1 further decreased NIS mRNA and protein expression that iodine inhibited at different iodine levels. In summary, we have shown that iodine downregulated NIS expression in cultured mammary gland explants from the lactating mouse. IGF-I and TGF-β1 inhibited NIS mRNA and protein expression in the mammary gland under different iodine levels.

Rheology and texture of starch gels containing iodine

The objective of this study was to investigate the textural and rheological properties of starch gels containing different levels of iodine. The research goal is to understand the architectural organization of granules by utilizing iodine as a marker. Corn (CS), wheat (WS), potato (PS) and tapioca (TS) starch gels containing varying concentrations of iodine were prepared in a Rapid Visco Analyser (RVA). The gels were analysed by using a rheometer for small-deformation properties and also by using a texture analyser for large deformation properties following storage for 1 or 7 days. With increasing concentration of iodine, the firmness of gels decreased and the extent of decrease varied for the different starches. The extent of change in complex modulus (G*) of the gels was highest in the A-type starch, CS, but was different from WS, which is also an A-type starch. The G* for PS gels (B-type) decreased with the addition of 0.1% iodine but there was no significant difference upon increasing the iodine concentration. The G* for the C-type TS gels was lower than 15 Pa. These observations suggest a difference in the microstructure of the starch gels formed, likely resulting from differential leaching of polymers.

Effect of iodine on polymer leaching and granule swelling of starches from different botanical sources

Iodine complexation with linear glucan polymers in starch granules is a function of the length of the available polymers and their arrangement within starch granules. In previous studies, this complex formation between iodine and glucan polymers has been shown to alter the pasting properties of starches from different botanical origins. In this study, the effect of iodine on the swelling capacities of corn (CS), wheat (WS), potato (PS) and tapioca (TS) starches was investigated by heating 8% starch slurry with different levels of iodine in a Rapid Visco Analyser (RVA). Increasing concentrations of iodine had an inverse effect on the swelling capacities of starches even though the granules were highly swollen, as observed in the micrographs. Furthermore, the composition of the leachate was different for the starches, suggesting that the swelling capacity was influenced largely by an increase or decrease in the amount of leachate and the absorption spectra of the leachate. The same amounts of iodine resulted in widely different swelling capacity values for the different starches, likely, suggesting differences in their granular architecture.

Dose and time-dependent hypercholesterolemic effects of iodine excess via TRβ1-mediated down regulation of hepatic LDLr gene expression

With the global improvement of iodine nutrition, iodine excess is emerging as a new concern. The aim of this study is to illustrate the physiological effects and potential molecular mechanisms of excessive iodine intake on lipid metabolism. Balb/c mice were given drinking water containing different levels of iodine for 1 month and treated with 1.2 microg/mL iodine for different periods of time, respectively. Plasma lipid parameters and serum thyroid hormones were measured. Expressions of hepatic genes were detected by real-time polymerase chain reactions and Western blot. Dose-dependent hypercholesterolemic effects were detected in mice (TC, r = 0.615; p < 0.01). Drinking 1.2 microg/mL iodine water for 1 month had no significant effect on serum lipid metabolism, while prolonged exposure induced an increase of serum cholesterol. Serum thyroid hormones were not affected by iodine throughout the study. At the molecular level, we detected a dose-dependent attenuation of hepatic low density lipoprotein receptor (LDLr) and thyroid hormone receptor beta1 (TRbeta1) expression in parallel to the change of serum cholesterol. Treatment with 1.2 microg/mL iodine water for 1 month did not affect LDLr and TRbeta1 expression, while 3 or 6 months exposure resulted in a decrease of their expression. Present findings demonstrated dose- and time-dependent hypercholesterolemic effects of iodine excess. Furthermore, our data suggests that TRbeta1-mediated down regulation of hepatic LDLr gene may play a critical role in iodine excess-induced hypercholesterolemic effects.

The effects of iodine/selenium on the function of antigen presentation of peritoneal macrophages in rats

To observe the effects of iodine/selenium on the function of antigen presentation of peritoneal macrophages in rats and explore the immunological mechanisms of iodine/ selenium's role in pathogenesis of autoimmune thyroid diseases (AITD). Female Lewis rats were randomly divided into four groups including (1) low selenium and normal iodine group (L(sE)N(I)) (2) low selenium and high iodine group (L(Se)H(I)) (3) normal selenium and normal iodine group (N(Se)N(I) ) (4) normal selenium and high iodine group (N(Se)H(I)). All rats were fed by a special diet with lower selenium and iodine in it and drunk ion-free water containing different levels of iodine and selenium for 3 months. Peritoneal macrophages of each group and OVA allergized T cells were prepared and cultured together. Then the function of antigen presentation were estimated by detecting the levels of IL-2 in the culture supernatant. The levels of the expression of co-stimulator CD86 in the spleen of each group were determined by RT-PCR. The level of IL-2 in the supernatant in N(Se)H(I) (43.22 +/- 3.27) pg/ml was much stronger than N(Se)N(I) [the level of IL-2 was (25.74 +/- 2.45) pg/ml, P < 0.05]. The level of IL-2 in L(Se)N(I) (15.79 +/- 2.13) pg/ml was significantly lower than N(Se)N(I) (P < 0.05). The expression of CD86 mRNA in N(Se)H(I) (CD86/beta-actin: 0.52 +/- 0.10) were higher than N(Se)N(I) (CD86/beta-actin: 0.35 +/- 0.04), P < 0.05. High iodine could promote the presentation function of macrophages to a higher state than normal. Therefore, high iodine intake might become an importantly inducing factor in thyroid autoimmunity. Low selenium could weaken the ability of recognizing and presenting OVA antigen of peritoneal macrophages which might destroy immunological homeostasis and thus the low selenium intake might also become an inducer of AITD.

Effect of Iodine Supplement on Iodine Status and 5\'-Deiodinase Activity in the Brain of Neonatal Rats with Iodine Deficiency

The weanling Wistar rats of iodine deficiency were divided into three groups for supplementation of different levels of iodine (iodine-excessive [IE], iodine-adequate [IA], and iodine-deficient [ID]), with a control group (C). The iodine content in the thyroid was determined by epithermal neutron activation analysis. The activities of 5'-deiodinase and 5-deiodinase in the brains were assayed by determining the conversion ratios of T4 to T3 and rT3, respectively. The thyroid hormones levels in serum were also tested. The results indicated that the ID group had a goiter containing a small amount of iodine, but the IE group had a slightly swollen thyroid with rich iodine; the concentration of iodine per unit mass of thyroid was lower in group IE than in groups IA and C. The highest 5'-deiodinase and lowest 5-deiodinase activities in group ID and the lowest 5'-deiodinase activity in group IE were found. The iodine deficiency or excess resulted in a compensated hypothyroid state. The results suggest that the iodine status and the deiodinases activities would become normal for the rats of iodine deficiency if adequate iodine is supplemented soon after birth. Meanwhile, it is also critical to avoid excessive intake of iodine to reduce the risk for overcorrecting.

Studies on the Iodine Requirements of White Rats during Growth, Pregnancy and Lactation

With rats grown for three successive generations on diets containing 25 to 525 μg of iodine per kilogram, the minimum dietary level needed to prevent thyroid enlargement was found to lie between 100 and 225 μg per kilogram. The growth rates of rats fed the different levels of iodine did not differ significantly. Lowering the iodine content of the diet of female rats to 25 μg per kilogram did not interfere with reproduction or lactation; however, the thyroids of the newborn from dams at this level had the appearance of embryonic glands.