Wortmannin, PI3K/Akt signaling pathway inhibitor, attenuates thyroid injury associated with severe acute pancreatitis in rats

Increasing evidences suggest that PI3K/AKT pathway plays an important role in the pathogenesis of inflammatory diseases such as acute pancreatitis. However, the exact effect of PI3K/AKT on thyroid injury associated with acute pancreatitis has not been investigated. This study aimed to investigate the protective effects of wortmannin, PI3K/AKT inhibitor, on thyroid injury in a rat model of severe acute pancreatitis (SAP). Sixty male SD rats were randomly divided into four groups: sham operating group (SO), SAP group, wortmannin treatment (WOR) group and drug control (WOR-CON) group. Serum amylase (AMY), lipase (LIP) and thyroid hormone levels were evaluated. The morphological change of thyroid tissue was analyzed under the light and transmission electron microscopy. AKT, P38MAPK and NF-κB expression in the thyroid tissue was evaluated by immunohistochemical staining. Oxidative stress and inflammatory cytokines were detected. Results showed that wortmannin attenuated the following: (1) serum AMY, LIP and thyroid hormone (2) pancreatic and thyroid pathological injuries (3) thyroid MDA, (4) thyroid ultrastructural change, (5) serum TNF-α, IL-6 and IL-1β (6) AKT, MAPKP38 and NF-κB expression in thyroid tissues. These results suggested that wortmannin attenuates thyroid injury in SAP rats, presumably because of its role on prevent ROS generation and inhibits the activation of P38MAPK, NF-κB pathway. Our findings provide new therapeutic targets for thyroid injury associated with SAP.

Geographic variations in the frequency of thyroid disorders and thyroid peroxidase antibodies in persons without former thyroid disease within Germany

OBJECTIVE

To investigate regional variations in the frequency of undiagnosed thyroid disorders among 25- to 88-year-old men and women in two communities in the northeast and the south of Germany. In addition, autoantibodies to thyroperoxidase (TPO-Abs) and urinary iodine excretion were determined.

METHODS

Two population-based surveys of men and women using a common standardized protocol, the Study of Health in Pomerania (SHIP) in the northeast of Germany (2505 participants) and the Kooperative Gesundheitsforschung in der Region Augsburg (KORA) in the south of Germany (2316 participants), were compared with regard to the frequency of undiagnosed thyroid disorders.

RESULTS

Compared with the northeast of Germany, urinary iodine excretion and serum thyroid-stimulating hormone (TSH) levels were significantly higher in the south. The median urinary iodine concentration was 110 μg/l (64; 169 μg/l) in SHIP and 151 μg/l (97; 214 μg/l) in KORA, and the median TSH value was 0.81 mIU/l (0.56; 1.15 mIU/l) in SHIP and 1.22 mIU/l (0.84; 1.80 mIU/l) in KORA. The frequency of elevated TSH (TSH ≥ 2.12 mIU/l) was 4.3% in SHIP and 14.1% in KORA (P<0.001); the corresponding values for suppressed TSH (<0.25 mIU/l) were 3.5 and 1.7% (P<0.001). The proportion of ultrasonographic findings was 55.5% in SHIP and 68.0% in KORA. The frequency of serum TPO-Abs did not differ significantly between northeast and south Germany.

CONCLUSIONS

There were considerable regional disparities in the frequency of thyroid disorders within Germany. These differences can be explained not only by different regional histories of natural iodine deficiency but also by current differences in the iodine supply under an identical nationwide iodine fortification program.

[Association of polymorph variants of CYP1A2 and CYP1A1 genes with reproductive and thyroid diseases in female workers of petrochemical industry]

The article presents results obtained in study of relationship between polymorph variants of CYP1A1 and CYP1A2 genes with reproductive and thyroid diseases risk in female workers of petrochemical industry, when compared with reference group females. Variants TD and DD of CYP1A2 gene appeared to be associated with nodes formation in uterus and breast in female workers and reference group females. Following liability markers are obtained: homozygous in rare allele genotype CC of CYP1A1 gene for reproductive and thyroid diseaes (fibrous cystic mastopathy and nodular goitre), heterozygous genotype AG of CYP1A1 gene in uterine myoma and fibrous cystic mastopathy, homozygous in deleted T genotype of CYP1A2 gene in autoimmune thyroiditis. Occupational hazards and long length of service at hazardous industries increase effects of rare alleles of the genes studied.

Further studies on delineating thyroid-stimulating hormone (TSH) reference range

The aim of the study was to evaluate thyroid-stimulating hormone (TSH) concentration in a reference group and to compare it with the TSH in subjects with high probability of thyroid dysfunction. The study population consisted of 852 subjects. The reference group consisting of 316 subjects was obtained by the exclusion of the subjects having thyroid disease, taking thyroid influencing drugs, having increased thyroid peroxidase (TPO) antibodies, or having abnormal thyroid ultrasound. 42 high probability of thyroid dysfunction subjects were defined by the association of increased TPO antibody concentration, changed echogenicity, and changed echosonographic structure of thyroid parenchyma. In the reference group TSH reference range was 0.45 mU/l (95% CI 0.39-0.56 mU/l) to 3.43 mU/l (95% CI 3.10-4.22 mU/l). To distinguish reference and high probability of thyroid dysfunction group a TSH threshold was calculated. At a threshold value of 3.09 mU/l (95% CI 2.93-3.38 mU/l), specificity was 95% and sensitivity 38.1%. Using 2 different approaches to find upper limit of the TSH reference range we obtained similar results. Using reference group only a value of 3.43 mU/l was obtained. Using both reference group and subjects with the high probability of thyroid dysfunction we obtained 95% CI for the upper reference limit between 2.93 and 3.38 mU/l. Based on these premises, it could be argued that conservative estimate of the TSH upper reference range should be 3.4 mU/l for both sexes.

[B-, H- and L-cathepsin-like activity in blood plasma of patients with diseases of the thyroid, parathyroid and adrenal glands]

B-, H- and L-catepsine-like activity regarding Na-benzoyl-D,L-arginine-4-nitroanilide, L-leucine-4-nitroanilide and azocasein was studied in the blood plasma of patients with different diseases of thyroid, parathyroid and adrenal glands. It has been shown that the high H- catepsine-like activity confirming the activation of blood catepsin H secretion accompanied by the tissue growth under any pathology took place in the blood plasma of patients with all the above diseases. High B- catepsine-like activity in the blood plasma of patients with thyroid diseases was exceptionally fixed under the nodular forms of thyroid pathology, while the character of changes in L catepsine-like activity under these diseases was not so natural. In diaseses of the adrenal glands the changes in the B- and L-catepsine-like activity were only shown in the blood plasma of patients with cerebral layer tumors but not the gland cortex: B-catepsine-like activity increased in the blood plasma of patients with benign or malignant tumors, and L-catepsine-like activity decreased under benign tumor from chromaffin tissue. The established picture of changes in enzymatic activity in the blood plasma of patients does not allow to think that the determination of blood B- and L- catepsine-like activity can be recommended for obtaining additional information at diagnosis thyroid diseases.

[Mechanism of apoptosis in the thyroid cells in thyroid pathology]

The literature data and the results of own examinations concerning the changes in programmed cell death processes of goiter alterated thyroid tissue in patients with euthyroid or toxic goiter and also the extranodular tissue of the gland in the presence of pathological changes in it (the pronounced hyperplastic process, sclerotic and/or dystrophic changes, lymphoid infiltration, chronic or autoimmune thyroiditis) were analyzed. It has been shown that the significant changes in the processes ofmitochondria and postmitochondria regulation and apoptosis realization are occurred under thyroid pathology. The character and the degree of disorders in the apoptosis mitochondria mechanisms and the activity of destructive processes in the patient thyroid cells are dependent on many factors such as the type of pathology, the severity of its occurrence, the peculiarities of tissue follicular structure and the patient sex. Obtained resistance of the apoptosis mitochondria mechanisms can play an important role in the pathogenesis of thyroid nodular pathology or in the development of inflammatory and autoimmune processes.

[The complex hygienic characteristics preventive iodine deficiency in population of Siberia]

In the research we used hygienic, social-hygienic and statistical methods. The study showed that 58,3-88,1% of examined children in Siberia, in the north, south and in the center of Krasnoyarsk territory suffer from iodine deficiency. There was no difference iodine content medians between boys and girls. Preventive iodine deficiency which arise at absence or decrease in food and are the reason of many illness, is important and till now a unresolved problem of Krasnoyarsk areas.

PTPN22: its role in SLE and autoimmunity

A functional variant of protein tyrosine phosphatase nonreceptor 22 (PTPN22) has recently been shown to be associated with multiple autoimmune diseases, including systemic lupus erythematosus (SLE), rheumatoid arthritis, type 1 diabetes, and autoimmune thyroid disease. In this review, we discuss the structure and function of this gene and its disease-associated polymorphisms. In addition, we review the studies investigating the association between this gene and SLE, along with other autoimmune diseases.

Characterisation of DEHAL1 expression in thyroid pathologies

Iodotyrosine dehalogenase 1 (DEHAL1) is a transmembrane protein involved in the recycling of iodide in the human thyroid. The aim of the present study was (I) to investigate whether DEHAL1 expression is different in differentially functioning thyroid pathologies and (II) to evaluate DEHAL1 as a possible marker of thyroid cell differentiation.

DESIGN AND METHODS

Real-time PCR for DEHAL1 and its isoform DEHAL1B was performed in a series of 105 thyroid specimens, including toxic thyroid nodules (TTN), Graves' disease (GD) thyroids, benign cold thyroid nodules (CTN), normal thyroid tissues and thyroid cancers (follicular thyroid carcinomas (FTC), papillary thyroid carcinomas (PTC), partially differentiated thyroid cancers (PDTC) and anaplastic thyroid carcinomas (ATC)). In addition, DEHAL1 protein expression was studied by immunohistochemistry in 163 benign and malignant thyroid pathologies and normal thyroids.

RESULTS

(I) The highest DEHAL1 mRNA levels were found in GD thyroids, while downregulation of DEHAL1 and DEHAL1B mRNA occurred in PTC and ATC (P<0.001 and <0.05 respectively); (II) DEHAL1 protein was overexpressed in TTNs and GD thyroids with predominant apical staining in all samples; (III) a weaker and patchy staining pattern was found in CTNs and normal thyroids; (IV) in differentiated thyroid cancers (FTC and PTC), a diffuse cytoplasmic DEHAL1 expression was found; and (V) in PDTC and ATC, DEHAL1 expression was faint or absent.

CONCLUSION

Upregulation of DEHAL1 protein expression and sublocalisation of DEHAL1 at the apical cell pole in TTNs and GD thyroids is consistent with increased thyroid hormone turnover during thyrotoxicosis. Diffuse cytoplasmatic localisation or downregulation of DEHAL1 expression in thyroid cancers suggests alteration or loss of DEHAL1 function during thyroid cell dedifferentiation.

Thyroid peroxidase immunohistochemistry in differential diagnosis of thyroid tumors

Thyroperoxidase (TPO) is a thyroid-specific enzyme expressed by differentiated thyroid cells. Initial immunohistochemical studies claimed that TPO expression, detected by the monoclonal antibody mAb 47, may be a potentially important diagnostic tool in differentiating malignant from benign lesions. However, some recent studies have failed to reproduce the earlier results, suggesting the limitations for TPO immunohistochemistry. To assess these observations we have evaluated the immunohistochemical expression of TPO in thyroid tissue from 215 patients. The studied material included 87 nonmalignant thyroid lesions and 128 thyroid carcinomas. TPO expression was investigated using newly available mAb 47 and staining of less than 80% of the follicular cells/specimen as the threshold indicating a malignant lesion. We found that TPO had a sensitivity of 89.9% for cancer and a specificity of 64.4% for nonmalignant lesions, showing that it does not give a sufficient degree of diagnostic certainty that the lesion is benign. In addition, the variability in the degree of TPO expression found within and between follicular carcinomas, and the significant number of benign adenomas having similar immunostaining patterns, assured us that TPO immunostaining is not sufficiently discriminatory in the differential diagnosis of thyroid cancer versus benign lesions.

Prevalence of abnormal thyroid stimulating hormone and thyroid peroxidase antibody-positive results in a population of pregnant women in the Samara region of the Russian Federation

Undiagnosed thyroid disease is a common problem with significant public health implications. This is especially true during pregnancy, when the health of both the mother and the developing child can be adversely affected by abnormal maternal thyroid function. Measurement of serum thyroid stimulating hormone (TSH) and thyroid peroxidase antibodies (TPO-Ab) are two common ways to assess maternal thyroid status. The objective of our study was to determine the prevalence of abnormal TSH and TPO-Ab tests in a population of pregnant women in the Samara region of the Russian Federation. Serum samples were obtained from 1588 pregnant women as part of their routine antenatal care. TSH and TPO-Ab were measured, and trimester-specific reference values for TSH (2.5–97.5 percentiles) were calculated using TPO-Ab-negative women. TSH results outside these ranges were considered abnormal; TPO-Ab levels outside the manufacturer's reference range (>12IU/mL) were considered abnormal. Overall, the prevalence of abnormal results was 6.3% for TSH and 10.7% for TPO-Ab. High TSH (>97.5 trimester-specific percentile) and TPO-Ab-positive results were most common in the first trimester (5.7% and 13.8%, respectively). TSH levels were associated with gestational age and TPO-Ab status, and with maternal age in TPO-Ab-negative women. TPO-Ab status was associated with both maternal and gestational age. Women with TSH >2.5mIU/L had a significantly increased risk of being TPO-Ab-positive, and this risk increased with age. Based on our data, we conclude that abnormal TSH and TPO-Ab are common in pregnant women of the Samara region. Given the association of thyroid dysfunction to adverse pregnancy outcomes, screening of this population for abnormal thyroid function should be considered.

Human thyroid phenol sulfotransferase enzymes 1A1 and 1A3: activities in normal and diseased thyroid glands, and inhibition by thyroid hormones and phytoestrogens

Sulfation by sulfotransferase enzymes (SULTs) is an important pathway for the metabolism of thyroid hormones and phytoestrogens. Intrathyroidal SULTs may contribute to the processing of thyroid hormones for the reutilization of iodide. SULT1A1 and SULT1A3 activities were identified in normal and diseased human thyroid glands. Biochemical properties that included apparent K(m) values, thermal stabilities, and responses to inhibitors were characterized in a normal human thyroid high speed supernatant pool. Apparent K(m) values for SULT1A1 and SULT1A3 activities with the model substrates p-nitrophenol and dopamine were 0.58 +/- 0.04 and 11.3 +/- 1.3 microm, respectively. Activities of SULT1A1 and SULT1A3 determined in individual normal thyroid (n = 35), nodular goiter (n = 26), and autoimmune thyroid disease (n = 25) glands were 0.34 +/- 0.06, 0.52 +/- 0.09, and 0.82 +/- 0.19 U/mg protein for SULT1A1, respectively, and 0.22 +/- 0.04, 0.21 +/- 0.04, and 0.48 +/- 0.11 U/mg protein for SULT1A3, respectively. Both SULT activities in autoimmune thyroid disease glands were significantly higher than those in normal thyroids. Only 3,3'-diiodothyronine (3,3'-T(2)) and the phytoestrogen daidzein served as substrates for the normal thyroid SULT activities, yet each thyroid hormone and phytoestrogen tested were found to inhibit thyroid SULT1A1 and SULT1A3 activities. The preference of thyroid gland SULT activities for 3,3'-T(2) suggests that sulfation may enhance degradation of intrathyroidal 3,3'-T(2) for iodide reutilization. Inhibition of these SULT activities by the exogenous phytoestrogens daidzein and genistein, with a potential decrease in iodide reutilization, presents another mechanism through which these compounds may adversely affect human thyroid function.

Activities of UDP-glucuronyltransferase, beta-glucuronidase and deiodinase types I and II in hyper- and hypothyroid rats

We have investigated the hypothesis that uridine 5'-diphosphate (UDP)-glucuronyltransferases (UGTs) and beta-glucuronidase are jointly involved in a mechanism for the storage and mobilization of iodothyronine metabolites in liver, kidney, heart and brain. Specifically, we predicted UGT activities to decrease and increase respectively, and beta-glucuronidase activity to increase and decrease respectively in hypo- and hyperthyroidism. To this end we have studied the effects of thyroid status on the activities of different enzymes involved in thyroid hormone metabolism in liver, kidney, heart and brain from adult rats with experimentally induced hypo- and hyperthyroidism. We used whole organ homogenates to determine the specific enzyme activities of phenol- and androsteron-UGT, beta-glucuronidase, as well as iodothyronine deiodinase types I and II. Deiodinase type I activities in liver and kidney were decreased in hypothyroid animals and, in liver only, increased in hyperthyroidism. Deiodinase type II activity was increased in hyperthyroid rat kidney only. Interestingly, in the heart, deiodinase type I-specific activity was increased fourfold, although the increase was not statistically significant. Cardiac deiodinase type I activity was detectable but not sensitive to thyroid status. Hepatic phenol-UGT as well as androsteron-UGT activities were decreased in hypothyroid rats, with specific androsteron-UGT activities two to three orders of magnitude lower than phenol-UGT activities. Both UGT isozymes were well above detection limits in heart, but appeared to be insensitive to thyroid status. In contrast, cardiac beta-glucuronidase activity decreased in hypothyroid tissue, whereas the activity of this enzyme in the other organs investigated did not change significantly. In summary, cardiac beta-glucuronidase, albeit in low levels, and hepatic phenol-UGT activities were responsive only to experimental hypothyroidism. Although a high basal activity of the pleiotropic beta-glucuronidase masking subtle activity changes in response to thyroid status cannot be ruled out, we conclude that hepatic, renal and cardiac UGT and beta-glucuronidase activities are not regulated reciprocally with thyroid status.

Development of studies of TPO gene and its application in nuclear medicine

Thyroperoxidase (TPO) is a glycosylated protein bound to the apical plasma membrane of thyrocytes. It is the key enzyme in the synthesis of thyroid hormones. Its gene structure and transcriptional regulation have been studied in detail. This article reviews the structure, function and transcriptional regulation of the TPO gene, and the relationship between TPO, thyroid diseases and radioactive iodide therapy.

Thyroid hormone deiodinases: physiology and clinical disorders

Thyroid hormone action is achieved through the binding of 3,5,3'-triiodothyronine to its nuclear receptor, which results in alterations in gene expression. An impairment in thyroid hormone action during vertebrate development results in severe, irreversible abnormalities in tissue growth, maturation, and function. The deiodinases are a family of selenoproteins expressed in a number of fetal and adult tissues that catalyze the activation and inactivation of thyroid hormones. Their unique biochemical characteristics and tissue and developmental expression patterns suggest that deiodinases may control the concentration of active thyroid hormone available to specific tissues or cell types at certain stages of development. The deiodinases thus appear to play an important role in regulating thyroid hormone action at a prereceptor level. Current research focusing on a better understanding of the biochemistry, regulation, and physiologic role of these enzymes is the focus of this review.

Serum paraoxonase 1 activity is decreased in thyroid dysfunction

Changes in serum lipid and lipoprotein concentrations occur frequently in disorders of thyroid function. LDL-cholesterol (LDL-C) oxidation susceptibility is higher in these patients than in normal population. This study aims at assessing lipids, lipoproteins, apolipoproteins and serum paraoxonase 1 (PON1) activity in patients with thyroid dysfunction. Ninety-nine patients with thyroid dysfunction, (49 hypothyroid and 50 hyperthyroid) were compared with 2 separately age- and sex-matched control groups. A fasting blood sample was obtained and serum total cholesterol, triglycerides, apolipoproteins A-I and B, and PON1 activity were measured. In hyperthyroid patients, significantly lower PON1 activity (45 +/- 23 vs 67 +/- 37 IU/ml, p<0.001), triglycerides (112 +/- 53 vs 166 +/- 130 mg/dl, p<0.05), apolipoprotein A-I (137 +/- 26 vs 154 +/- 21 mg/dl, p<0.001) and apolipoprotein B (75 +/- 18 vs 86 +/- 25 mg/dl, p<0.05) were found. Hypothyroid patients had lower PON1 activity (46 +/- 21 vs 64 +/- 32 IU/ml, p<0.005) compared with controls, and higher total cholesterol (224 +/- 69 vs 185 +/- 41 mg/dl, p<0.001), LDL-C (133 +/- 59 vs 93 +/- 36 mg/dl, p<0.001), and apolipoprotein B (107 +/- 37 vs 84 +/- 23 mg/dl, p<0.001). The results show significant changes of lipid levels in thyroid dysfunction. In addition, a significant reduction in PON1 activity was observed in both hyper- and hypothyroid patients. Increased LDL-C oxidation in thyroid dysfunction observed in other studies, at least to some extent, can be attributed to reduced PON1 activity.

Autoantibodies against glutamic acid decarboxylase and 21-hydroxylase in Brazilian patients with type 1 diabetes or autoimmune thyroid diseases

Autoimmune thyroid diseases (ATD) are often associated with Type 1 diabetes mellitus (T1DM) and Addison's disease (AD), characterizing the autoimmune polyendocrine syndrome. We evaluated the frequency of autoantibodies against glutamic acid decarboxylase isoform 65 (GAD65Ab) and 21-hydroxylase (21OHAb) in the sera of 65 [58 females (F)/7 males (M), 17-70 yr] patients with Graves' disease (GD) and 47 (45 F/2 M, 12-77 yr) with Hashimoto's thyroiditis (HT), none of whom had either diabetes or AD. The sera of 30 recently diagnosed T1DM patients (16 M/14 F, 1-39 yr) and of 97 (54 F/43 M, 7-69 yr) healthy controls were also examined. GAD65Ab were detected in the sera of 18 (60%) T1DM, 8 (12%) GD and in none of the HT patients or the controls (p = 0.03 for GD vs HT, p = 0.002 for GD vs controls, and p < 0.001 for GD vs T1DM). 21OHAb were detected in the sera of 2 (3%) GD, 1 (2%) HT and in none of the T1DM patients or the controls. GAD65Ab levels were significantly lower in GD than in T1DM patients (median: -0.06 vs 0.28, p < 0.001). Six of the 8 GD GAD65Ab-positive patients submitted to an intravenous glucose tolerance test showed no diminished first phase insulin secretion. All 21OHAb positive patients had normal basal cortisol and adrenocorticotropin (ACTH), normal cortisol response after ACTH stimulation, but high plasma renin activity. In conclusion, despite the genetic diversity of the Brazilian population, the frequency of GAD65Ab and 21OHAb in our patients is similar to that observed in other countries. GAD65Ab were more prevalent in GD than in HT patients, suggesting a difference in the immune response between these disorders. Long-term follow-up is necessary to determine the clinical relevance of these autoantibodies in the Brazilian population.

[Thyroid peroxidase antibodies and thyroid diseases in children and adolescents with newly diagnosed type I diabetes]

The objective of the authors was to evaluate the prevalence of TPO Ab and thyroid diseases in children with newly diagnosed type 1 diabetes. The examination included 153 patients (85/55.6% girls) from southeast Poland aged 11 months to do 17.4 years (mean age 9.5 +/- 3.9 years). Apart from clinical assessment, all children had determinations made of serum TPO Ab, FT4 and TSH, while thyroid ultra sound was performed in each patients with abnormal thyroid morphology and/or positive TPO Ab titter. Positive TPO Ab was detected in 45 patients (29.4%). In this group 26 had isolated serum TPO Ab elevation, 18 had Hashimoto's disease, 1 Graves's disease. Another 12 children (7.8%) were demonstrated to have euthyroid goiter. Thyroid abnormalities were thus seen in 37.2% children with newly diagnosed type 1 diabetes. No association was demonstrated between the prevalence of thyroid abnormalities and sex. Children with subclinical stage of autoimmune thyreoiditis were significantly younger in comparison to patients with Hashimoto's disease (8.9 +/- 4.2 vs. 12.0 +/- 3.1 years) and had significantly lower serum TPO Ab and TSH levels (314.2 +/- 232.4 vs. 2076.8 +/- 1300.8 U/ml, 1.7 +/- 0.82 vs. 4.1 +/- 2.9 ulU/ml, respectively). Thyroid dysfunction was detected in 7 (4.6%) children with newly diagnosed type 1 diabetes. In comparison to the entire group with positive serum TPO Ab titer in these 7 children the percentage of patients with thyroid dysfunction was significantly higher (15.5%). Six patients were hypothyroid and 1 had hyperthyreosis. The present results justify the need for comprehensive screening for thyroid disorders in all children with newly diagnosed type 1 diabetes.

Breast cancer in association with thyroid disorders

BACKGROUND

The relationship between breast cancer and thyroid diseases is controversial. Discrepant results have been reported in the literature. The incidences of autoimmune and nonautoimmune thyroid diseases were investigated in patients with breast cancer and age-matched control individuals without breast or thyroid disease.

METHODS

Clinical and ultrasound evaluation of thyroid gland, determination of serum thyroid hormone and antibody levels, and fine-needle aspiration of thyroid gland were performed in 150 breast cancer patients and 100 control individuals.

RESULTS

The mean values for anti-thyroid peroxidase antibodies were significantly higher in breast cancer patients than in control individuals (P = 0.030). The incidences of autoimmune and nonautoimmune thyroid diseases were higher in breast cancer patients than in control individuals (38% versus 17%, P = 0.001; 26% versus 9%, P = 0.001, respectively).

CONCLUSION

Our results indicate an increased prevalence of autoimmune and nonautoimmune thyroid diseases in breast cancer patients.

Detection of thyroid peroxidase mRNA in peripheral blood of patients with malignant and benign thyroid diseases

The aim of this study was to evaluate thyroid peroxidase (TPO) mRNA expression in peripheral blood of patients with benign and malignant thyroid disease. Included were 120 thyroid cancer patients, 85 patients with goitre or Graves' disease (GD) and 54 healthy volunteers. TPO mRNA expression was analysed in peripheral blood by nested RT-PCR. In cancer patients, RT-PCR results were compared with staging, grading and serum thyroglobulin (TG) measurement. TPO transcripts were detected in 7/10 (70%) patients with known metastases of thyroid cancer and in 39 of 110 (36%) patients without metastases (P<0.05), in 15/44 (34%) patients with goitre, in 17/41 (41%) cases with GD and in 4/54 (7.4%) subjects in the control group (P<0.05, controls vs all patients with thyroid disease). Among cancer patients without metastatic disease, RT-PCR results correlated positively with lymph node status (P=0.05), grading (P=0.01) and elevated serum thyroglobulin levels (P=0.03). This is the largest study investigating the use of the TPO-RT-PCR assay. Positivity in TPO-RT-PCR correlates significantly with metastatic disease in cancer patients and with the presence of thyroid disease in general. To date, TPO-RT-PCR cannot substitute for standard techniques in the diagnosis of local recurrence or metastatic spread in thyroid cancer patients. However, as results of TPO-RT-PCR correlate significantly with lymph node status, grading and serum TG measurements in patients with non-metastatic disease, TPO seems to be an interesting molecular marker to look at in follow-up studies.

Thyroid carcinomas that express telomerase follow a more aggressive clinical course in children and adolescents

With each cell division, DNA is lost from the telomeres, limiting the number of divisions, and leading to senescence. Malignant tumors maintain immortality by expressing a specific DNA repair enzyme, telomerase, that replaces this DNA. We hypothesized that tumors which express telomerase would have the highest recurrence risk and we tested this by determining telomerase expression in 27 papillary thyroid carcinomas (PTC), 5 follicular thyroid carcinomas (FTC) and 13 benign thyroid lesions from children and adolescents. Patients were 6-21 yr of age (mean+/-SE=16.6+/-4.1 yr) and followed from 0-14.1 yr (mean+/-SE=4.71+/-3.5 yr). Original tumors were sectioned, and immunostained for telomerase. Telomerase-specific staining was determined by two independent, blind examiners and graded from absent (Grade 0) to intense (Grade 3). Telomerase was detected in a similar majority of benign (11/13, 85%) and malignant tumors (24/32, 75%). However, the intensity of telomerase expression was greater among FTC (mean+/-SE=2.4+/-0.5 relative intensity) followed by PTC (mean+/-SE=1.9+/-1.0 relative intensity) and benign tumors (mean+/-SE=1.8+/-1.0 relative intensity). Autoimmune lesions had lower telomerase expression (mean+/-SE=1.25+/-0.5 relative intensity) compared to FTC (p=0.01), PTC (p=0.06) and benign lesions (p=0.15). Among PTC, 19 (70%) expressed telomerase, and 8 (30%) did not. Direct invasion (no.=4, 21%), distant metastasis (no.=2, 10%) and recurrence (no.=7, 37%) developed exclusively in PTC that expressed telomerase (p=0.02). Disease-free survival was also shorter for PTC that expressed telomerase (p=0.06). Recurrence developed in 1/2 (50%) FTC that expressed telomerase. We conclude that childhood thyroid cancers which express telomerase have an increased risk of tissue invasion, metastasis, and recurrence.

[Plasminogen activators of urokinase and tissue types and their inhibitor (PAI-1) in cytosol fraction in thyroid diseases]

Enzyme immunoassay (ELISA) was used to estimate the levels of plasminogen activators of urokinase (uPA) and tissue (tPA) types and one of their inhibitors (PAI-I) in the cytosolic fraction of the thyroid in 129 patients with malignant and benign tumors and various non-cancer diseases of the gland. Tumors from patients with thyroid cancer displayed the lowest levels of tPA and the highest levels of uPA and PAI-I, while those from patients with benign thyroid diseases, including adenoma, had high concentrations of tPA and relatively low levels of uPA and PAI-I in the tissue of the diseased organ. At the same time, the lowest levels of uPA and PAI-I were found in patients suffering from toxic goiter with and without adenomatosis. In terms of uPA and PAI-I levels, patients with nodular colloidal goiter were intermediate between those with toxic goiter and adenoma, on the one hand, and those with thyroid cancer, on the other.

Is there loss or qualitative changes in the expression of thyroid peroxidase protein in thyroid epithelial cancer?

There is disagreement concerning the expression of thyroid peroxidase (TPO) in thyroid cancer, some studies finding qualitative as well as quantitative differences compared to normal tissue. To investigate TPO protein expression and its antigenic properties, TPO was captured from a solubilizate of thyroid microsomes by a panel of murine anti-TPO monoclonal antibodies and detected with a panel of anti-human TPO IgGkappa Fab. TPO protein expression in 30 samples of malignant thyroid tissue was compared with TPO from adjacent normal tissues. Virtual absence of TPO expression was observed in 8 cases. In the remaining 22 malignant thyroid tumours the TPO protein level varied considerably from normal to nearly absent when compared to normal thyroid tissue or tissues from patients with Graves' disease (range less than 0.5 to more than 12.5 microg mg(-1) of protein). When expressed TPO displayed similar epitopes, to that of TPO from Graves' disease tissue. The results obtained by the TPO capturing method were confirmed by SDS-PAGE and Western blot analysis with both microsomes and their solubilizates. The present results show that in about two-thirds of differentiated thyroid carcinomas, TPO protein is expressed, albeit to a more variable extent than normal; when present, TPO in malignant tissues is immunologically normal.

Expression of reduced nicotinamide adenine dinucleotide phosphate oxidase (ThoX, LNOX, Duox) genes and proteins in human thyroid tissues

The large homolog of NADPH oxidase flavoprotein LNOX2, and probably LNOX1, are flavoproteins involved in the thyroid H(2)O(2) generator. Western blot analysis of membrane proteins from normal human thyroid, using antipeptide antibodies, indicated that LNOX1,2 are 164-kDa glycoproteins and that N-glycosylated motifs account for at least 10-20 kDa of their total apparent molecular mass. Northern blot analysis of 23 different human tissues demonstrated that LNOX2 messenger RNA (mRNA) is strongly expressed only in the thyroid gland, although blast analysis of expressed sequence tags databases indicated that LNOX genes are also expressed in some nonthyroid cells. We investigated LNOX1,2 gene and protein expressions in normal and pathological human thyroid tissues using real-time kinetic quantitative PCR and antipeptide antibodies, respectively. In normal tissue, LNOX1,2 are localized at the apical pole of thyrocytes. Immunostaining for LNOX1,2 was heterogeneous, inside a given follicle, with 40-60% of positive follicular cells. Among normal and pathological tissues, variations of LNOX1 and LNOX2 mRNA levels were parallel, suggesting a similar regulation of both gene expressions. Whereas LNOX mRNAs seemed slightly affected in benign disease, the expression of protein was highly variable. In multinodular goiters, 40-60% of cells were stained. In hypofunctioning adenomas, LNOX immunostaining was highly variable among follicles, whereas sodium/iodide (Na+/I-) symporter immunostaining was decreased. In hyperfunctioning thyroid tissues, only few cells (0-10%) were weakly stained, whereas sodium/iodide symporter staining was found in the majority of follicular cells. In conclusion, LNOX proteins are new apical glycoproteins with a regulation of expression that differs from other thyroid markers.

Prostaglandin endoperoxide H synthase expression in human thyroid epithelial cells

KAT-50, an established human thyrocyte cell line, expresses constitutively high levels of prostaglandin endoperoxide H synthase-2 (PGHS-2), the inflammatory cyclooxygenase. Here, we examine primary human thyrocytes. We find that they, too, express PGHS-2 mRNA and protein under control culture conditions. A substantial fraction of the basal prostaglandin E(2) (PGE(2)) produced by these cells can be inhibited by SC-58125 (5 microM), a PGHS-2-selective inhibitor. Interleukin (IL)-1beta (10 ng/ml) induces PGHS-2 expression and PGE(2) production in primary thyrocytes. The induction of PGHS-2 and PGE(2) synthesis by IL-1beta could be blocked by glucocorticoid treatment. Unlike KAT-50, most of the culture strains also express PGHS-1 protein. Our observations suggest that both cyclooxygenase isoforms may have functional roles in primary human thyroid epithelial cells, and PGHS-2 might predominate under basal and cytokine-activated culture conditions.

Association between serum concentrations of hexachlorobenzene and polychlorobiphenyls with thyroid hormone and liver enzymes in a sample of the general population

OBJECTIVES

Hexachlorobenzene (HCB) is a highly lipophilic organochlorine compound of widespread environmental occurrence, that accumulates in the biological system. It affects the porphyrine metabolism, thyroid hormones, and the liver function in animals. Although HCB is one of the most common organochlorine compound in humans, little investigation on its health effects has been done. Polychlorobiphenyls (PCBs) are also widespread toxic environmental contaminants. The aim of the present study was to investigate the association of serum HCB and PCB concentrations with thyroid hormone status and liver enzymes in human.

METHODS

Thyroid stimulating hormone (TSH), total and free thyroxine (T4), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) were measured as biological markers of thyroid and liver function in a rural population sample older than 14 years (n=192, except for TSH with n=608) highly exposed to HCB. Serum concentrations of HCB were measured by gas chromatography coupled to electron capture detection.

RESULTS

After adjustment for confounding variables, there was a significant negative association between serum HCB concentrations and total T4 (a decrease of 0.32 microg/dl per each unit, ln ng/ml, of increase of HCB) and a positive association with GGT (a relative increase of 10 % per each ln unit of increase of HCB), although most subjects (92%) were within the normal range for both T4 and GGT. These associations were not modified after adjustment for total lipid content or for other organochlorine compounds. The association of T4 and GGT with PCB was smaller although significant. No association was found with the other biochemical markers.

CONCLUSIONS

These results suggest that the internal dose of HCB of this population may reflect a subtle metabolic effect on thyroid function and an enzymatic induction activity. Further studies are needed to evaluate the health impact of these effects in more susceptible populations, such as infants.

Immunohistochemical study of ceruloplasmin, lactoferrin and secretory component expression in neoplastic and non-neoplastic thyroid gland diseases

The expression of lactoferrin (LF), ceruloplasmin (CP) and secretory component (SC) in various thyroid diseases was investigated using an immunohistochemical method. LF is an iron-binding protein overexpressed in certain human adenocarcinomas. CP is implicated in carcinogenesis and SC is part of the local immune defense system. Sections of 15 follicular adenomas, 5 follicular carcinomas (FC), 16 papillary carcinomas (PC), 15 goitres and 2 cases of lymphocytic thyroiditis were re-examined and investigated immunohistologically by a streptavidin-biotin method. A positive immunostain reaction for CP and LF was observed in all cases of PC and FC. A positive immunostain reaction for SC was observed in 13/16 cases of PC and 4/5 cases of FC. A negative immunostain reaction for CP, LF and SC was observed in medullary cancers, in follicular adenomas and in the cases with goitre. We conclude that the immunostain expression of LF, CP and SC is a valuable diagnostic aid in the differential diagnosis between benign and malignant thyroid tumors. The expression of SC indicates the presence of a local immunodefensive system.

Telomerase activity and telomere length in benign and malignant human thyroid tissues

Several studies have demonstrated that telomerase is activated and telomere length is altered in various types of tumors. In this study, we investigated telomerase activities and telomere length in 21 thyroid tumors. Telomerase activity was detected in 11 of 12 thyroid cancers and three of nine follicular adenomas. The mean telomere lengths in the cancers tissue and follicular adenomas were lower than in the respective background tissues, the differences being significant (P=0.0055 and P<0.006), respectively. Our findings suggest that change in telomerase activity and telomere length may be important for development of thyroid tumors.

Telomerase activity in lesions of the thyroid: application to diagnosis of clinical samples including fine-needle aspirates

The telomerase enzyme is capable of replacing telomeric DNA sequences that are lost at each cell division. It has been suggested that the function of this enzyme is necessary for cells to become immortal, and in concordance with this hypothesis, telomerase activity has been detected in malignant tumor cells, whereas the enzyme is inactive in normal somatic cells. The measurement of this activity in human tissue samples may have diagnostic value, and in this study, we examined whether such a measurement may be useful for the detection of malignant cells within the thyroid. Telomerase activity was assayed using the telomeric repeat amplification protocol and related to the histological diagnosis of thyroid biopsy tissue samples and of cells obtained from the thyroid by fine-needle aspiration (FNA). Extracts from 9 of 11 (82%) carcinoma biopsy tissue samples contained telomerase activity, whereas enzyme activity was detected in only 2 of 14 (14%) benign tissue sample extracts. These two positive cases were subsequently diagnosed as Graves' disease with severe lymphocytic infiltration. Five of six (83.3%) histologically confirmed carcinoma FNA samples were identified by using the telomeric repeat amplification protocol assay, and two samples considered to be suspicious by FNA cytology were also positive. Conversely, only 4 of 48 (8.3%) benign FNA samples had telomerase. These promising data indicate that this sensitive assay could become a useful adjunct to microscopic cytopathology in the detection of cancer cells in small tissue biopsies and in fine-needle aspirates of the thyroid.

Role of the hepatic xanthine oxidase in thyroid dysfunction: effect of thyroid hormones in oxidative stress in rat liver

The effect of thyroid hormones on the hepatic xanthine oxidase activity was studied in rats after the intraperitoneal injections of comthyroid (triiodotyronine:thyroxine = 1:4) at 0.3 mg/kg for 3 consecutive days. The aim of this study was to understand the precise mechanism of hyperthyroidism induced by oxidative stress. The concentration of lipid peroxides determined indirectly by the measurement of thiobarbituric acid reactants was increased in comthyroid treated rats. The hepatic glutathione content was decreased in comthyroid injected rat compared to the euthyroid state. It was also observed that the increment of xanthine oxidase activity has a profound role in oxygen radicals generation system in comthyroid treated rat. These findings suggest that the enhanced xanthine oxidase activity and depleting glutathione content in comthyroid treated rats result in pathophysiological oxidative stress including an increment of hepatic lipid peroxidation.

Telomerase activity in benign and malignant human thyroid tissues

Telomerase is a specialized ribonucleoprotein polymerase that directs the synthesis of telomerase repeats at chromosome ends. Accumulating evidence has indicated that telomerase is stringently repressed in normal human somatic tissues but reactivated in cancers and immortal cells, suggesting that activation of telomerase activity plays a role in carcinogenesis and immortalization. In this work, the status of telomerase activity during the development of human thyroid cancer was determined using telomeric repeat amplification protocol (TRAP) in 14 nodular hyperplasia, 14 adenomas, 23 papillary carcinomas and 11 follicular carcinomas. Positive telomerase activity was detected in 2 of 14 nodular hyperplasias (14%), 4 of 14 adenomas (29%), 12 of 23 papillary carcinomas (52%) and 10 of 11 follicular carcinomas (91%). The cancers that are negative for telomerase activity are mostly in early stage (stage I or II). These results suggest that telomerase reactivation plays a role during the development of thyroid cancer.

Telomerase activity in benign and malignant thyroid diseases

BACKGROUND

Telomerase, an enzyme associated with cellular immortality, is expressed by most malignant cells and is inactive in most normal somatic cells, with the excitation of proliferative stem cells, male germ cells, and activated lymphocytes. The measurement of telomerase activity in clinically obtained tissue samples may provide useful information as both a diagnostic and prognostic marker. In this study, we sought to determine whether telomerase activity might prove helpful in the assessment of benign and malignant thyroid tumors.

METHODS

A modified, semiquantitative polymerase chain reaction-based telomeric repeat amplification protocol assay was used for detection of telomerase activity in 59 samples obtained at thyroidectomy, including 15 thyroid cancers, 22 benign thyroid diseases, and 22 adjacent normal thyroid tissues.

RESULTS

Four of 13 differentiated thyroid carcinomas (30%) and 2 of 2 medullary carcinomas (100%) expressed telomerase activity. Unexpectedly, we also detected activity in 3 of 22 (14%) adjacent normal thyroid tissues and 6 of 22 (28%) benign thyroid diseases. Pathologic review of the telomerase-positive benign specimens revealed that many contained extensive lymphoid infiltrates with germinal centers (six of nine, 67%), as did two of four telomerase-positive papillary carcinomas.

CONCLUSIONS

In contradistinction to other epithelial carcinomas, telomerase does not appear to be frequently reactivated in differentiated thyroid carcinomas.

Expression of nitric oxide synthase III in human thyroid follicular cells: evidence for increased expression in hyperthyroidism

Nitric oxide mediates a wide array of cellular functions in many tissues. It is generated by three known isoforms of nitric oxide synthases (NOS). Recently, the endothelial isoform, NOSIII, was shown to be abundantly expressed in the rat thyroid gland and its expression increased in goitrous glands. In this study, we analyzed whether NOSIII is expressed in human thyroid tissue and whether levels of expression vary in different states of thyroid gland function. Semiquantitative RT-PCR was used to assess variations in NOSIII gene expression in seven patients with Graves' disease, one with a TSH-receptor germline mutation and six hypothyroid patients (Hashimoto's thyroiditis). Protein expression and subcellular localization were determined by immunohistochemistry (two normal thyroids, five multinodular goiters, ten hyperthyroid patients and two hypothyroid patients). NOSIII mRNA was detected in all samples: the levels were significantly higher in tissues from hyperthyroid patients compared with euthyroid and hypothyroid patients. NOSIII immunoreactivity was detected in vascular endothelial cells, but was also found in thyroid follicular cells. In patients with Graves' disease, the immunostaining was diffusely enhanced in all follicular cells. A more intense signal was observed in toxic adenomas and in samples obtained from a patient with severe hyperthyroidism due to an activating mutation in the TSH receptor. In multinodular goiters, large follicles displayed a weak signal whereas small proliferative follicles showed intense immunoreactivity near the apical plasma membrane. In hypothyroid patients, NOSIII immunoreactivity was barely detectable. In summary, NOSIII is expressed both in endothelial cells and thyroid follicular cells. The endothelial localization of NOSIII is consistent with a role for nitric oxide in the vascular control of the thyroid. NOSIII expression in thyroid follicular cells and the variations in its immunoreactivity suggest a possible role for nitric oxide in thyrocyte function and/or growth.

Biochemical composition of benign thyroid cyst fluid

Although the availability of thyroid cyst fluid is easy by fine-needle aspiration, less is known about the biochemical composition of thyroid cyst fluid. The authors have, therefore, determined the biochemical composition of 18 benign thyroid cyst fluid specimens. They found that the activities of aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and the concentrations of total protein, total bilirubin, and uric acid were highly increased in thyroid cyst fluid specimens when compared with normal human serum specimens. The concentrations of glucose, cholesterol, and triglycerides in cyst fluid were within normal serum limits. Selenium (Se) concentrations in most cyst fluids were low. Moreover, there was no correlation between Se and other biochemical parameters. Protein electrophoresis of cyst fluid specimens yielded high concentrations of alpha 1 and especially alpha 2 globulin fractions indicating an inflammation. The concentrations or activities of biochemical analytes were not significantly different in pure and mixed cysts. Those parameters were also not significantly different between cyst fluids of different colors. The gross appearance of the fluid and the presence of certain biochemical analytes were consistent with a hemorrhagic origin of most of the cyst fluid specimens. However, some biochemical markers indicate that autolysis or necrosis of thyroid tissue may also contribute the composition of thyroid cyst fluid. The reason for lower Se concentration in the thyroid cyst fluid may be the lower Se concentration in the Turkish population. These results also suggest that the fluid color or nature of cyst, e.g., pure or mixed cyst, is not a main determinant of biochemical composition of benign thyroid cyst fluid.

[Methodical evaluation of immunoluminometric determination of thyroid peroxidase in serum]

With the identification of thyroid peroxidase (TPO) as the specific autoantigen in autoimmune diseases of the thyroid, the development of a commercial assay for detection of TPO in human serum became possible. The diagnostic value of this TPO assay was evaluated in 194 patients with various thyroidal diseases. The assay appeared to be easily affected by specific and/or unspecific interferences such as TPO-auto-antibodies in the patient's blood samples. To analyze these effectors every sample was checked in a parallel recovery test. In most of the cases with elevated anti-TPO levels an exact determination of TPO could not be estimated correctly. Whenever a correct measurement of TPO was possible, to none of the different examined groups of thyroid diseases a correlation of TPO-levels could be demonstrated. Moreover, the value of TPO determination as a tool in the follow-up of differentiated thyroid carcinoma was not provable. For the time being our studies do not suggest TPO measurements being helpful in thyroidal diagnosis.

Effects of thyroid hormone on erythrocyte carbonic anhydrase-I and zinc concentrations in vivo and in vitro: clinical usefulness of carbonic anhydrase-I and zinc concentrations in erythrocytes

Red blood cell (RBC) carbonic anhydrase-I isozyme (CAI) and zinc concentrations were measured in patients with various thyroid diseases. Both concentrations were decreased in patients with hyperthyroid Graves' disease, and the RBC CAI concentration significantly (r = 0.95) correlated with the RBC zinc concentration. After treatment, the normalization of RBC CAI and zinc lagged 2 months behind normalization of plasma T4 and T3 levels. Furthermore, the highest correlation coefficients were observed between RBC CAI and zinc levels and plasma thyroid hormone levels measured 8 weeks earlier. These results indicate that both RBC CAI and zinc levels reflect the integrated plasma thyroid hormone levels over the previous few months. Transient thyrotoxicosis due to destructive (subacute or painless) thyroiditis did not cause significant changes in the RBC CAI and zinc concentrations. Therefore, the measurement of RBC CAI and zinc concentrations may be useful in differentiating patients with Graves' disease from those with transient thyrotoxicosis. T3 at a physiological free concentration significantly decreased CAI concentration in erythroleukemic YN-1 cells and burst forming unit-erythroid-derived cells obtained by culturing peripheral blood mononuclear cells. These cells may be useful in vitro models for investigations of thyroid hormone action in human erythroid cells.

Different cytokine mRNA profiles in Graves' disease, Hashimoto's thyroiditis, and nonautoimmune thyroid disorders determined by quantitative reverse transcriptase polymerase chain reaction (RT-PCR)

Intrathyroidal lymphocytes are a source of cytokines thought to stimulate or maintain the immune process within the thyroid in Graves' disease (GD) and Hashimoto's thyroiditis (HT). Quantitative assessment of the cytokine profile may provide important clues as to the Th1/Th2 balance prevailing in these diseases. We analyzed cytokine mRNA expression levels in thyroid tissue samples from 13 patients with GD, 2 with HT, 5 with nontoxic multinodular goiter (NTG), and 4 with thyroid autonomy (nodular = TAnod and perinodular = TAperi tissue) using multispecific competitor fragments with primer sequences for IL-1 beta, IL-2, IL-4, IL-6, IL-8, IL-10, IFN-gamma, CD25, and CD3 delta-chain mRNA. Patients with GD were subdivided into two groups according to their serum levels of antibodies to thyroperoxidase (anti-TPO; GDhigh > 4000 U/mL, GDlow < or = 200 U/mL). These levels correlated positively with the CD3 delta-chain mRNA levels (r = 0.83) and with the T cell infiltration (r = 0.71) as determined by immunohistochemistry. Patients with GDhigh demonstrated 2- to 4-fold higher IL-4 mRNA levels (as compared to all other investigated groups) and significantly higher IL-10 mRNA levels as compared to HT, GDlow, and TAnod patients. Patients with GDhigh also had significantly higher levels of IFN-gamma, IL-1 beta, IL-8, and CD25 mRNA as compared to GDlow. The highest IFN-gamma, IL-2, and CD25 mRNA levels were found in HT. The lowest mRNA levels of all the investigated groups were detected in TAnod. No significant differences in IL-6 and IL-8 mRNA levels were found between most of the patient groups. In summary, patients with GDhigh showed a shift to a more Th2-driven cytokine pattern. In contrast, the increase mRNA levels of Th1-related cytokines found in HT indicate predominantly T cell-mediated cytotoxic processes.

Expression of dipeptidyl aminopeptidase IV activity in thyroid tumours: a possible marker of thyroid malignancy

The role of dipeptidyl aminopeptidase IV (DAP IV) activity staining in the investigation of a thyroid mass was explored. The study consisted of two parts: the first part involved DAP IV staining performed on various thyroid lesions sampled from operative specimens. These included frozen tissues or cytologic smears. The second part of the study, which is ongoing, prospectively examines the DAP IV activity in fine-needle aspiration (FNA) specimens from patients with a thyroid mass. Results from part 1 of the study indicated that DAP IV activity staining was a useful adjunct in distinguishing differentiated carcinoma from benign lesions, particularly the "follicular lesions." Preliminary findings of the second part of the study suggest that DAP IV staining can be applied to FNA specimens. The measure of DAP IV activity and its influence on the diagnostic accuracy of FNA remain to be seen.

CD26 (dipeptidyl peptidase IV/DPP IV) as a novel molecular marker for differentiated thyroid carcinoma

In this report we show that CD26 (dipeptidyl peptidase IV/DPP IV) is a novel molecular marker for differentiated thyroid carcinoma. Northern-blot analysis of 22 various thyroid tissues revealed that CD26 is a more specific marker of differentiated thyroid carcinoma than 3 proto-oncogenes previously reported to increase mRNA expression in thyroid carcinomas: c-met, c-erbB-2 and EGF-R. A comparative study of 3 CD26 assays, Northern blotting, immunohistochemical staining and activity staining clearly showed that CD26 enzyme activity staining is the most specific assay for differentiated thyroid carcinoma, yet the easiest to perform. Activity staining of 216 thyroid tissues detected CD26 in all 52 papillary carcinomas and all 5 follicular carcinomas, while all 58 cases of Graves' disease were CD26-negative. Among benign neoplasms, 54 of 55 adenomatous goiters and 29 of 33 follicular adenomas were CD26 negative. Staining intensity of the enzyme activity was relative to the degree of CD26 mRNA expression. Southern-blot study showed no gene amplification or major translocation of the CD26 gene in 7 papillary carcinomas examined. Based on this study, ectopic expression of CD26 in differentiated thyroid carcinomas is thought to be mainly caused by increased CD26 mRNA expression. In conclusion, CD26 activity staining is a simple, specific assay which should be added to the usual pathological examinations in order to distinguish differentiated thyroid carcinomas from benign thyroid diseases.

Subchronic toxicity study in rats with 1-methyl-3-propylimidazole-2-thione (PTI): effects on the thyroid

A 90-day gavage study was performed to evaluate the subchronic toxicity of 1-methyl-3-propylimidazole-2-thione (PTI) when administered to Crl:CD BR rats. PTI is a chemical catalyst and is structurally similar to the thioureas, which are known to adversely affect the thyroid. Therefore, this study was designed to investigate the effects of PTI on the thyroid. Male and female rats were dosed with 0, 5, 10, 25, or 75 mgPTI/kg/day for 13 weeks. Clinical pathology examinations and pathology examination were performed and the following were measured periodically: serum T3, T4, and TSH, hepatic UDP-glucuronyltransferase activity, and cell proliferation of the thyroid and liver. Under the conditions of this study, the overall no-observed-adverse-effect level (NOAEL) for the subchronic effects of PTI in male and female rats was 10 mg PTI/kg/day. The NOAEL was based on the effects on the thyroid gland in male and female rats dosed with 25 and 75 mg PTI/kg/day, as well as the hepatic centrilobular fatty change, increased severity of chronic progressive nephropathy, fatty change in the adrenal medulla, and the substantial reduction in body weight and body weight gain. The primary target organs were the thyroid and liver. Alterations in thyroid hormones (T3, T4, and TSH) occurred predominantly at 25 and 75 mg/kg/day. Toxicologically significant alterations in T3, T4, and TSH levels, cell proliferation, and UDP-glucuronyltransferase activity occurred in rats dosed with 25 and 75 mg/kg/day, which correlated with organ weight and histopathological effects. Additionally, the effect of PTI on thyroid peroxidase activity, a key step in thyroid hormone synthesis, was evaluated in vitro using microswine thyroid microsomes. PTI was shown to inhibit thyroid peroxidase, with an IC50 of 0.02 M. These data suggest that PTI enhances the excretion of T4 via induction of glucuronyltransferase and inhibits thyroid hormone synthesis via a direct affect on thyroid peroxidase. Both of these effects contribute to the disruption of the hypothalamic-pituitary-thyroid axis and result in sustained elevation of TSH and the corresponding thyroid hypertrophy and hyperplasia.

Genetic and epitopic analysis of thyroid peroxidase (TPO) autoantibodies: markers of the human thyroid autoimmune response

TPO autoantibodies, the hallmark of human autoimmune thyroid disease, are of IgG class and are associated with thyroid destruction and hypothyroidism. Using the immunoglobulin gene combinatorial library approach, a panel of human monoclonal TPO autoantibodies (expressed as Fab) has been generated from thyroid tissue-infiltrating B cells. TPO-specific Fab closely resemble patients' serum autoantibodies in terms of L chain type, IgG subclass, affinities for TPO as well as epitopes recognized by > 80% of TPO autoantibodies in an individual's serum. TPO autoantibody V region genes are not unique; H chain V genes are usually mutated, while L chain V genes are sometimes in germ-line conformation. The autoantibodies recognize an immunodominant region involving conformational, overlapping epitopes in domains A and B. Finally, TPO autoantibody epitopic fingerprints are distinctive for individual sera, are not associated with hypothyroidism, but are conserved over time (indicating a lack of B cell epitope spreading). Evidence for conservation as well as inheritance of the fingerprints in some families, together with VH gene polymorphisms, may provide insight into the genetic basis of human autoimmune thyroid disease. Furthermore, monoclonal human TPO autoantibodies will be invaluable for B cell presentation of TPO to determine the T cell epitopes involved in TPO autoantibody production.

[Study of type I and IV collagenase activity in human thyroid diseases]

The activity of type I and IV collagenase was measured in thyroid tissue obtained from 6 non-diseased thyroids, 4 patients with Graves' diseases, 5 with follicular adenoma, 6 with papillary carcinoma and 4 with follicular carcinomas. The relationship between these enzyme activities and invasion or metastasis of the original tumors was studied. The activity of type I collagenase in papillary carcinomas and follicular carcinomas was higher than in non-diseased thyroids, Graves' disease and follicular adenoma. Carcinoma tissue with invasion beyond the capsule in particular had higher type I collagenase activity. Type IV collagenase activity in carcinoma with lymph node metastasis was higher than in non-diseased thyroids, Graves' disease and follicular adenoma, and especially higher than carcinoma without lymph node metastasis. These findings suggest that increased type I collagenase activity plays an important role in local invasion in thyroid carcinoma, and that increased type IV collagenase activity plays an important role in lymph node metastasis.

Hyperinsulinaemia and Na+, K(+)-ATPase activity in thyrotoxic periodic paralysis

OBJECTIVE

Thyrotoxic periodic paralysis (TPP) usually follows a heavy carbohydrate meal and this may be explained by hyperinsulinaemia stimulating Na+, K(+)-ATPase activity. To clarify this the effect of glucose load on serum insulin concentration and platelet Na+, K(+)-ATPase activity in thyrotoxic periodic paralysis (TPP) was examined.

DESIGN

In all subjects a standard 75-g glucose tolerance test was done and blood samples were taken at 0, 1 and 2 hours.

SUBJECTS

Twenty-five healthy controls (8 M and 17 F), 17 uncomplicated thyrotoxic patients (7 M and 10 F), 15 TPP patients who presented with paralysis and 4 TPP patients after treatment with antithyroid drugs.

MEASUREMENTS

Plasma glucose was measured by the glucose oxidase method, serum insulin by radioimmunoassay and platelet Na+, K(+)-ATPase by the release of phosphate from ATP.

RESULTS

TPP patients showed glucose intolerance (area under the curve (AUC) 16.5 +/- 4.4 (mean +/- SD) in TPP compared to 12.9 +/- 4.5 in controls (P < 0.01)) and hyperinsulinaemia (AUC 189.6 +/- 100.6 vs 98.5 +/- 53.4, P < 0.001). In uncomplicated thyrotoxicosis the results were similar to that in healthy controls. Platelet Na+, K(+)-ATPase were significantly higher in thyrotoxic patients compared to controls and in TPP patients were even higher. Ingestion of glucose increased platelet Na+, K(+)-ATPase in all groups. AUC for platelet Na+, K(+)-ATPase in TPP patients were significantly higher than in uncomplicated thyrotoxicosis (601 +/- 99.3 vs 482 +/- 109.4, P < 0.01) or healthy controls (320 +/- 107.3). In the 4 TPP patients studied after antithyroid treatment the results were similar to healthy controls.

CONCLUSION

Patients with thyrotoxic periodic paralysis have hyperinsulinaemia and this is accompanied by higher Na+, K(+)-ATPase activity.

Immunohistochemical demonstration of thyroid peroxidase (TPO) in human thyroid tissues from various thyroid diseases

Human thyroid peroxidase (hTPO) was detected immunohistochemically in 61 normal, benign and malignant thyroid tissues with a monoclonal antibody (38E) against hTPO using paraffin-embedded sections. Thyroid peroxidase was expressed intensely not only in tissues from Graves disease and hyperfunctioning adenomas, but also in those from carcinomas, adenomas and Hashimoto's thyroiditis. The staining pattern of TPO in the follicular cells was a diffuse and fine granular one in the normal thyroids, Graves' thyroids and adenomas, but abnormal coarse granular deposits of TPO were characteristically identified in most of the papillary carcinomas and Hashimoto's thyroiditis. These coarse granular deposits of TPO suggested that qualitative or structural changes in the TPO molecule are present in carcinomas and Hashimoto's thyroiditis. Consequently, these qualitative changes in TPO may be responsible for the lack of biochemically measured TPO activity in these diseases. This finding may also be useful in distinguishing between benign and malignant thyroid tumors.

Anti-thyroid peroxidase (anti-TPO) antibodies in thyroid diseases, non-thyroidal illness and controls. Clinical validity of a new commercial method for detection of anti-TPO (thyroid microsomal) autoantibodies

The identification of the thyroid peroxidase (TPO) as the main antigen of the thyroid microsomal fraction has enabled the development of a sensitive and specific assay for detection of the corresponding autoantibodies. We evaluated the diagnostic validity of the anti-TPO assay in 303 patients with different types of thyroid disease and in controls. Clearly elevated anti-TPO values (anti-TPO > 500 units/ml) were found in 59% of patients with thyroiditis but in none of the controls or the patients with non-thyroidal illness. The mean anti-TPO levels in these two control groups were 26 +/- 31 units/ml (mean +/- S.D.) and 39 +/- 34 units/ml, respectively. The highest frequency of positive results (88%) was obtained in patients with auto-immune hypothyroidism (clinical diagnosis: Hashimoto's thyroiditis) followed by patients with Graves' disease (53%). With a cut-off point of 200 units/ml, a sensitivity of 96% was obtained for Hashimoto's thyroiditis and of 59% for Graves' disease with a specificity of 100% (50 cases). The new method (anti-TPO, Dynotest) was compared with three conventional methods (35 samples). The results for all measurements were in general agreement. In two cases the results were clearly discordant: one sample contained high anti-thyroglobulin antibody concentrations, the other was obtained from a patient with non-thyroidal illness. In both instances the 'classical' assays yielded false-positive results. Treatment of autoimmune hyperthyroidism resulted in a median decrease in anti-TPO levels of over 50% after reaching the euthyroid state (P < 0.05), whereas in persistent hyperthyroidism no consistent changes were observed. In autoimmune hypothyroidism a marked variability in anti-TPO levels was noted. Some patients showed a clear decrease in anti-TPO levels during T4 substitution whereas in others no consistent changes were observed.

A study of the 3,5,3'-triiodothyronine sulfation activity in the adult and the fetal rat

We have employed a new in vitro assay for study of the T3 sulfation activity in rat tissues. The assay measures by RIA the generation of T3 sulfate (T3S) during incubation of T3 with cytosol of rat tissues as the source of phenol sulfotransferase(s) and 3-phosphoadenosine-5'-phosphosulfate as the sulfate donor. The conversion of T3 to T3S proceeded rapidly for 30 min at 37 C, and the optimal pH of the reaction was 8.0. Heating the cytosol at 44 C for 15 min decreased T3S production to 63% of its value at 37 C. T3 sulfation activity was plentiful in rat liver, brain, and kidney, but little activity was demonstrable in other tissues. The Km and maximum velocity of the hepatic conversion of T3 to T3S were 114 microM and 159 pmol/mg protein.h, respectively. There was a marked inhibition of the conversion of T3 to T3S with salicylamide, 3'-monoiodothyronine, thyronine, and rT3; the IC50 of these inhibitors approximated 15, less than 0.1, 9.5, and 43 microM, respectively. On day 17 of gestation, the T3 to T3S conversion activity was more abundant in fetal skin than in other fetal tissues. However, the activity decreased in fetal skin while it increased in fetal liver, kidney, and brain nearer to term on day 20. Placenta demonstrated lower T3 to T3S conversion activity than several fetal or maternal tissues. There was no effect of hypothyroidism or hyperthyroidism on T3 sulfation activity. We conclude that T3 sulfation activity in the rat is 1) most abundant in liver, kidney, and brain tissues of the adult; 2) inhibited more avidly by 3'-monoiodothyronine than other thyronines; 3) very abundant in fetal skin early in gestation; and 4) little affected by the thyroidal status of the animal.

[Study of the localization and the concentration of superoxide dismutase in various thyroid disorders]

The localization of Cu/Zn and Mn superoxide dismutase (SOD), which catalyzes the dismutation of superoxide radicals (O2-) to O2 and H2O2, in various thyroid disorders was studied by an immunohistochemical technique in 20% formalin fixed paraffin embedded thin sections using anti-human Cu/Zn and Mn-SOD antibodies. The concentrations of both SODs in those tissues were also measured by a sandwich enzyme immunoassay technique. Cu/Zn SOD was immunocytochemically stained in most of papillary carcinoma, and some of other disorders. In the normal follicular cells it localized in the perinuclear cytoplasm, whereas in the tumor or hyperplastic cells it was in the cytoplasm homogeneously. Mn SOD was strongly stained in papillary carcinoma and papillary growing cells in adenoma and Graves' disease. The concentrations of Cu/Zn and Mn SOD in every thyroid disorder were higher than those in normal thyroid, and it was much higher in the malignant tumors. The ratio of the concentration of Mn SOD against Cu/Zn SOD in the tissues was higher only in papillary carcinoma compared with that in normal thyroid. In conclusion, SOD seems to be relating to the cell proliferation and differentiation in the thyroid since both SODs increased in tumors and hyperplastic disorders, and Cu/Zn SOD changed its localization and Mn SOD existed predominantly in papillary carcinoma or papillary growing cells.