Diagnosis and management of amiodarone-induced thyrotoxicosis in Europe: results of an international survey among members of the European Thyroid Association

OBJECTIVE

To determine how expert European thyroidologists assess and treat amiodarone-induced thyrotoxicosis (AIT).

DESIGN

Members of the European Thyroid Association (ETA) with clinical interests were asked to answer a questionnaire on the diagnosis and management of AIT. A total of 124 responses were received: 116 from Europe, seven from USA and one from Brazil. After excluding responses coming from the same centre, 101 responses from 24 European countries were analysed, representing approximately 65% of clinically active European ETA members.

RESULTS

The majority of respondents (68%) see 1-10 new cases of AIT/year, and AIT seems to be more frequent than amiodarone-induced hypothyroidism in Europe, where in many instances iodine intake is borderline or moderately deficient. A good collaboration with cardiologists exists in most centres, and patients receiving chronic amiodarone treatment are checked for thyroid function most commonly every 4-6 months. When AIT is suspected, a diffuse or nodular goitre is present or in the absence of apparent abnormalities of the thyroid, free thyroxine (FT4), free triiodothyronine (FT3) and TSH are assayed by almost 90% of respondents. Thyroid autoimmunity is evaluated in the initial assessment by > 80%, while evaluation of urinary iodine excretion is unhelpful for > 60%. Most commonly used additional diagnostic procedures include thyroid ultrasonography, particularly colour flow Doppler sonography, and, to a lesser extent, a thyroid uptake scan. If the thyroid gland is apparently normal, measurement of thyroidal radioactive iodine uptake is considered useful by a large proportion of respondents to establish the destructive nature of the process. Differentiation of type I and type II AIT is difficult and, possibly, not correct for 27% of respondents, who believe that mixed (or indefinite) forms are probably more frequent than previously recognized. Approximately 10-20% do not consider amiodarone withdrawal necessary in the therapeutic strategy of AIT, especially if the thyroid gland is apparently normal. Most respondents (82%) treat type I AIT with thionamides, either alone (51%) or in combination with potassium perchlorate (31%), while the preferred treatment for type II AIT is represented by glucocorticoids (46%). Some respondents, in view of diagnostic difficulties, initially treat all cases of AIT with a combination of thionamides and glucocorticoids. After restoration of euthyroidism, ablative therapy is recommended by 34% in type I and only 8% in type II AIT. If amiodarone therapy needs to be reinstituted, prophylactic thyroid ablation is recommended by 65% in type I AIT, while a wait-and-see strategy is adopted by 70% in type II AIT.

CONCLUSION

Areas of certainty and uncertainty concerning AIT are present among expert European thyroidologists, both from a diagnostic and a therapeutic standpoint. Diagnostic criteria need to be refined in order to improve therapeutic outcome.

Serum prostate-specific antigen concentration is increased in acromegalic women

Prostate-specific antigen (PSA) is a serine proteases produced by prostatic epithelial cells detectable in male serum and seminal plasma. PSA is also expressed in some female tissues and fluids and is increased in hirsute women showing a positive correlation with androgens. Accordingly, it has been suggested that PSA might be a marker of androgen action in women. The aim of this observational study was to assess serum PSA concentration in acro megalic women with active disease, in remission or during somatostatin analogs therapy. Forty-four acromegalic women, 15 with active disease, 10 in remission and 19 under long-acting somatostatin analogs therapy were enrolled in the study; 273 normal women matched for age, body mass index, with no signs of hirsutism, served as controls. Serum PSA, 3a-androstanediol (3alpha-AG), total testosterone (T), DHEAS, LH, FSH and estradiol were assessed. No patient or control had been given estrogen or antiandrogen drugs; no acromegalic women had hyperprolactinemia or hypopituitarism. Serum PSA concentration was significantly higher in acromegalic patients than in control subjects (p < 0.0001). Patients with active acromegaly or under somatostatin analogs therapy had significant higher serum PSA concentration than controls, while patients in remission after adenomectomy did not differ. Serum PSA was detectable in serum of 75% acromegalic women and 45% of controls. In addition 24% of acromegalic women had serum PSA concentrations higher than the mean +/- 2SD of control subjects. Differences in serum PSA levels did not reach statistical significance in the different acromegalic subgroups possibly because of the small number of subjects, but patients with active acromegaly had higher serum PSA levels than patients under somatostatin analogs therapy or in remission. Acromegalic women had significantly higher serum PSA concentrations than controls both before and after menopause (p < 0.01). 3alpha-AG (p < 0.05) and T (p < 0.01) were higher in acromegalic than in control subjects in pre-menopause (PM) but not in post-menopause (M). A correlation was found in the whole group of acromegalic patients between serum PSA and 3a-AG concentrations (r = 0.3, p < 0.01). In conclusion, acromegalic is associated with an increase in serum PSA concentrations as a group, although this increase is observed, at an individual level, in only 24% of cases. Patients whose disease is controlled by somatostatin analogs or has been cured by pituitary adenomectomy tend to have lower serum PSA levels than patients with active disease. M patients tend to have lower PSA values than PM women, consistent with the main androgen control of PSA production. However, the observation that M women still have higher serum PSA levels than controls suggest that in acromegaly PSA is regulated not only by androgens but also by the GH/IGF-I system itself.

Growth hormone inhibits apoptosis in human colonic cancer cell lines: antagonistic effects of peroxisome proliferator activated receptor-gamma ligands

GH has antiapoptotic effects on several cells. However, the antiapoptotic mechanisms of GH on colonic mucosa cells are not completely understood. Peroxisome proliferator activated receptor-gamma (PPARgamma) activation enhances apoptosis, and a link between GH and PPARgamma in the colonic epithelium of acromegalic patients has been suggested. We investigated the effects of GH and of PPARgamma ligands on apoptosis in colonic cancer cell lines. Colonic cells showed specific binding sites for GH, and after exposure to 0.05-50 nm GH, their apoptosis reduced by 45%. The antiapoptotic effect was due to either GH directly or GH-dependent local production of IGF-1. A 55-85% reduction of PPARgamma expression was observed in GH-treated cells, compared with controls (P < 0.05). However, treatment of the cells with 1-50 microm ciglitazone (cig), induced apoptosis and reverted the antiapoptotic effects of GH by increasing the programmed cell death up to 3.5-fold at 30 min and up to 1.7-fold at 24 h. Expression of Bcl-2 and TNF-related apoptosis-induced ligand was not affected by either GH or cig treatment, whereas GH reduced the expression of Bax, which was increased by cig treatment. In addition, GH increased the expression of signal transducer and activator of transcription 5b, which might be involved in the down-regulation of PPARgamma expression. In conclusion, GH may exert a direct antiapoptotic effect on colonic cells, through an increased expression of signal transducer and activator of transcription 5b and a reduction of Bax and PPARgamma. The reduced GH-dependent apoptosis can be overcome by PPARgamma ligands, which might be useful chemopreventive agents in acromegalic patients, who have an increased colonic polyps prevalence.

PPARgamma inhibits GH synthesis and secretion and increases apoptosis of pituitary GH-secreting adenomas

OBJECTIVE

The objective of the study was to evaluate the expression and functional activity of Peroxisome proliferator-activated receptor (PPAR) gamma in pituitary adenomas from 14 consecutive acromegalic patients and to establish its role in apoptosis.

SUBJECTS AND METHODS

Fourteen consecutive acromegalic patients were enrolled in the study. Wistar-Furth rats were used for in vivo studies. Expression of PPARgamma was evaluated by RT-PCR and Western blot. Apoptosis and cell cycle were assessed by FACS analysis. The effects of PPARgamma ligands on transcriptional regulation of GH gene were evaluated by RT-PCR and electromobility shift assay.

RESULTS

PPARgamma was expressed in all human GH-secreting adenoma (GH-oma), in normal pituitary tissue samples (39+/-24% and 78+/-5% of immunostained nuclei respectively; P<0.0002; ANOVA), and in rat GH-secreting (GH3) cells. A PPRE-containing reporter plasmid transfected into GH3 cells was activated by ciglitazone or rosiglitazone (TZDs), indicating that PPARgamma was functionally active. Treatment of GH3 cells with TZDs increased apoptosis in a dose-dependent manner (P=0.0003) and arrested cell proliferation, reducing the number of cells in the S-phase (P<0.0001 vs untreated cells). TZDs increased the expression of TRAIL, leaving unaffected that of p53 and Bax. TZDs reduced GH concentrations in the culture media from 43.7+/-5.4 ng/ml to 2.1+/-0.3 ng/ml (P<0.0001) and in cell extracts (P<0.004). PPARgamma-RXRalpha heterodimers bound to GH promoter, inhibiting its activity and reducing GH mRNA levels (1.8 x 10(6) vs 5.7 x 10(6) transcripts respectively vs untreated cells; P<0.002). Subcutaneous GH-oma developed in rats injected with GH3 cells; tumor growth increased in placebo-treated rats and to a lesser extent in TZDs-treated animals (24.1+/-2.0 g, and 14.8+/-4.2 g respectively, P<0.03). Serum GH concentrations were lower in TZDs-treated rats than in controls (871+/-67 ng/ml vs 1.309+/-238 ng/ml; P<0.05).

CONCLUSIONS

The results of this study indicate that PPARgamma controls GH transcription and secretion as well as apoptosis and growth of GH-oma; thus, TZDs have the potential of a useful tool in the complex therapeutic management of acromegalic patients.

Mutations in the SLC26A4 (pendrin) gene in patients with sensorineural deafness and enlarged vestibular aqueduct

Pendred syndrome and the enlarged vestibular aqueduct (EVA) are considered phenotypic variations of the same entity due to mutations in the SLC26A4 (pendrin) gene. Pendred syndrome consists in sensorineural deafness, goiter and impaired thyroid hormone synthesis while in EVA thyroid function seems to be preserved. The aim of this study was to evaluate thyroid function and morphology and to look for mutations in the SLC26A4 gene in patients presented with EVA. Among 57 consecutive patients with sensorineural deafness 15 with EVA, as assessed by magnetic resonance imaging (MRI), were identified and studied. A complete evaluation of thyroid function including thyroid echography and perchlorate discharge test was carried out in all patients with EVA; all exons of the SLC26A4 gene were amplified from peripheral leukocytes and directly sequenced, using specific intronic primers. Out of 15 patients with EVA, goiter was present in 8 (53%), hypothyroidism in 7 (47%), increased serum thyroglobulin levels in 8 (53%) and a positive perchlorate discharge test in 10 (67%). Nine alleles of the SLC26A4 gene were mutated: 2 novel mutations (L465W and G497R) and 4 already known mutations (T410M, R409H, T505N and IVS1001+1G>A) were found. Four subjects were compound heterozygous and 1 heterozygous (G497R/wt). All patients harbouring mutations in the SLC26A4 gene had goiter and a positive perchlorate discharge test: 3 were slightly hypothyroid and 2 euthyroid. The remaining 10 patients had no mutations in the SLC26A4 gene: 4 of them were hypothyroid, 2 with goiter and positive perchlorate discharge test, 2 without goiter and with negative perchlorate discharge test. Two patients without mutations were euthyroid with positive perchlorate discharge test. Patients with mutations in the SLC26A4 gene had larger thyroid volume (p<0.002), higher serum thyroglobulin (Tg) levels (p<0.002) and greater radioiodine discharge after perchlorate (p=0.09) than patients without mutations. The results of the present study lend support to the concept that all patients with mutated SLC26A4 gene have abnormalities of thyroid function tests.

Relationship between management of hyperthyroidism and course of the ophthalmopathy

The relationship between treatment for hyperthyroidism and course of Graves' ophthalmopathy (GO) has been and still is a matter of debate. Literature often presents conflicting data, due to several influencing factors, such as selection bias, nonrandomized and uncontrolled or retrospective features of many studies, nonstandardized evaluation of ocular changes. However, it seems clear that neither antithyroid drug treatment nor thyroidectomy affect the natural course of GO, while radioiodine therapy may cause, in about 15% of cases, GO progression. The latter is more likely in patients who smoke, have pre-existing GO and more severe hyperthyroidism, or whose post-radioiodine hypothyroidism is not promptly corrected by L-thyroxine. GO progression after radioiodine therapy can be prevented by concomitantly treating patients with glucocorticoids, thus making radioiodine therapy a safe procedure also in GO patients. The presence of GO should not, therefore, influence the choice of treatment for hyperthyroidism. Should antithyroid drug treatment or thyroidectomy be selected for patients with mild ophthalmopathy, no treatment for GO is necessary, while a short course of moderate doses of glucocorticoids is advised if radioiodine therapy is chosen. In patients with severe GO, treatment of hyperthyroidism and management of GO proceed independently of each other, and either definitive (radioiodine or thyroidectomy) or conservative (antithyroid drugs) treatment for hyperthyroidism can be selected while treating GO. The authors' preference goes to the former, because it depletes intrathyroidal autoreactive T lymphocytes and removes thyroid antigens, which are likely to be involved in the pathogenesis of autoimmune reactions of the ophthalmopathy.

Improvement of growth hormone deficiency in patients with primary hyperparathyroidism after parathyroidectomy: results of a prospective study

GH secretion is impaired in most patients with primary hyperparathyroidism (PHP), although the secretion of the other anterior pituitary hormones is unaffected. However, whether restoration of euparathyroidism is associated with reversal of GH deficiency in PHP patients is not known. To address this issue, we studied 30 consecutive patients with PHP due to a single parathyroid adenoma before and after parathyroidectomy. GH secretion was evaluated by peak serum GH after the maximal GHRH + arginine (Arg) stimulation test. A group of 35 age- and sex-matched normal subjects served as controls. Serum IGF-I concentration was below the normal age- corrected values in six of 30 patients before surgery and in four of 30 patients after parathyroidectomy (P = not significant). Mean serum peak GH values after the GHRH + Arg test were 17.5 +/- 2.8 micro g/liter before surgery and 23.8 +/- 2.5 micro g /liter after surgery (P = 0.0008). The GH response to the GHRH + Arg test was reduced in 20 (67%) and normal in 10 (33%) of 30 PHP patients at baseline; after surgery, 22 of 30 (73%) PHP patients had a normal GH response to the GHRH + Arg test, and only eight (27%) had an impaired GH secretion (P < 0.02). In conclusion, this study confirms that GH secretion is impaired in PHP patients and indicates that it is reversed in many patients after parathyroidectomy. Accordingly, GH deficiency in PHP patients must be considered a functional phenomenon for which GH therapy is not recommended.

Graves' ophthalmopathy: state of the art and perspectives

Graves' ophthalmopathy (GO) is an autoimmune orbital disorder most commonly associated with Graves' disease. Recent studies have underscored the role that orbital cells, particularly fibroblasts and adipocytes, play in causing the increase in orbital content responsible for clinical manifestations of the disease. GO seems to be related to autoimmune reactions triggered by autoreactive T lymphocytes of thyroid origin, which recognize antigen(s) shared by thyroid and orbit. The nature of the antigen (or antigens) involved is not fully understood, but TSH receptor is likely to be involved. Cytokines secreted by T lymphocytes, macrophages and fibroblasts play an essential role in perpetuating the disease. Animal models of GO have been developed, but results have not clarified GO pathogenesis yet. Progress in the management of the ophthalmopathy has been very limited, and glucocorticoids, orbital radiotherapy and orbital decompression remain the mainstays in GO treatment. Novel treatments, such as somatostatin analogues, antioxidants, cytokine antagonists are currently under investigation, as well as the effects of total thyroid ablation. Cessation of smoking currently represents the only form of GO (secondary and tertiary) prevention.

Colonic polyps of acromegalic patients are not associated with mutations of the peroxisome proliferator activated receptor gamma gene

Peroxisome proliferator activated receptor (PPAR)gamma plays a pivotal role in regulating adipocyte differentiation and metabolism, but also has an antiproliferative effect in several tissues, including colonic mucosa, where it is highly expressed. Loss-of-function mutations have been reported in about 10% of sporadic primary colon cancer. Acromegalic patients have an increased prevalence of colonic neoplasms and lower PPARgamma levels in the colonic mucosa. Thus, PPARgamma may act as a tumor suppressor gene, and its reduced expression or loss-of-function mutations may contribute to tumorigenesis. In this study the expression and mutations of the PPARgamma gene in the colonic polyps and mucosa outside polyps were investigated in 10 acromegalic and 17 non-acromegalic patients. PPARgamma expression was evaluated by RT-PCR. PPARgamma was expressed in each sample, but expression appeared to be lower in polyps than in mucosa outside polyps from either acromegalic or non-acromegalic patients. All exons of the PPARgamma gene were directly sequenced after PCR amplification: no mutations were found either in acromegalic or in non-acromegalic patients. In conclusion, the results of this preliminary study suggest that the lower expression of PPARgamma rather than somatic mutations of this gene is involved in colonic tumorigenesis.

Effects of a mixture of polychlorinated biphenyls (Aroclor 1254) on the transcriptional activity of thyroid hormone receptor

Polychlorinated biphenyls (PCBs) are environmental contaminants which may affect thyroid function. PCBs may reduce serum thyroid hormone (TH) concentrations by either displacing T4 from TH transport proteins or increasing its hepatic metabolism. The reduced serum T4 causes neurological and growth defects in animals exposed to PCBs during the perinatal period, which can partially be reverted by T4 administration. In addition to a hypothyroid-like syndrome, a direct action of PCBs on TH-sensitive genes has been postulated. In the present study the effects of Aroclor 1254 (ARO), a mixture of PCBs, on transcription of TH-dependent genes were investigated. A reporter plasmid containing the TH-responsive element (TRE) of malic enzyme (ME) gene was used in transient transfections to assess the responsiveness to ARO. ARO (10 microM) reduced the CAT activity by about 50% and competed with T3 to reduce the induction of transcription. Cotransfection of TH receptor (TR) and a wild type TRE was required to reveal ARO inhibitiry effect, which was abolished by a mock reaction not containing TR or by a mutated TRE. ARO reduced the 125I-T3 binding to TR by 30%, but did not affect the interaction of TR with a 32P-labeled TRE in gel shift assay. ARO is likely to produce a conformational change in in vitro translated TR, leading to its increased proteolysis by trypsin. These results demonstrate that ARO interacts with TR, thereby affecting the transcription of TH-sensitive genes, and provide a molecular basis to further explain the complex effects of PCBs on TH disruption.

Changes in the expression of the peroxisome proliferator-activated receptor gamma gene in the colonic polyps and colonic mucosa of acromegalic patients

Acromegalic patients have an increased prevalence of colonic neoplasms and lower peroxisome proliferator-activated receptor gamma (PPARgamma) levels, the latter acting as a tumor suppressor gene. In this study we evaluated the expression of PPARgamma in the biopsy samples of the polyps and outside polyps colonic mucosa from seven patients with active, untreated acromegaly, 11 with cured disease, and 15 controls. Serum GH and IGF-I levels were higher in patients with untreated acromegaly than in those with acromegaly in remission or controls (P = 0.003 and P = 0.002, respectively) The expression of PPARgamma mRNA (mean +/- SE) was 1) mucosa outside polyps, 24,188 +/- 3,254 transcripts in the controls, 22,432 +/- 2,006 transcripts in acromegaly in remission, and 1,952 +/- 342 transcripts in untreated acromegaly (P < 0.0001 vs. controls and acromegaly in remission); and 2) polyps mucosa, 1,554 +/- 236 transcripts in the controls, 1,112 +/- 143 in acromegaly in remission, and 1,570 +/- 251 in untreated acromegaly (P = NS among polyps groups and mucosa outside polyps of untreated acromegaly; P < 0.0001 vs. mucosa outside polyps of controls and acromegaly in remission). Eighty-five percent of the cells in the mucosa outside polyps from controls or acromegaly in remission were positive at immunohistochemistry, at variance with 45% of the cells from polyps mucosa from each group and from those of mucosa outside polyps of untreated acromegaly (P = 0.0002). In conclusion, patients with untreated acromegaly have reduced expression of PPARgamma in the mucosa outside polyps, which might be reversed by curing the disease; conversely, patients with acromegaly in remission have the same low levels of expression of PPARgamma in the polyps mucosa as untreated acromegaly or controls, supporting the concept that reduced expression of PPARgamma might be an early event in colonic tumorigenesis.

Long-term safety of orbital radiotherapy for Graves' ophthalmopathy

We investigated the long-term side-effects of orbital radiotherapy (OR) in 204 patients with Graves' ophthalmopathy (GO), irradiated from 1972-1996 [44 by cobalt unit (CU) and 160 by linear accelerator (LA), mostly combined with glucocorticoids], with a 5- to 25-yr follow-up (median, 11 yr). Cataract was observed in 21 patients (10%) 3-21 yr after OR, with a higher (not significant) prevalence in CU-treated patients (18% vs. 8% in LA-treated patients). The prevalence of cataract was higher, although not significantly, in CU-treated patients aged less than 60 yr, but not in LA-treated patients, compared with the general population. Mild, asymptomatic retinopathy was observed in 1 of 7 patients (14%) with diabetes and hypertension, in 1 of 31 patients (3%) with hypertension alone, and in 0 of 11 patients with diabetes alone. No tumors were observed in 157 patients submitted to computed tomography scan of orbital and adjacent regions. In conclusion, OR is a safe treatment, not associated with an increased frequency of cataract, provided a high voltage apparatus is used. Hypertension, especially if associated with diabetes, may represent a relative contraindication, as it may cause retinopathy. Although no secondary tumors were detected, due to the long latency of radiation-induced tumors, OR should be restricted to patients older than 35 yr.

Thyroid color flow doppler sonography and radioiodine uptake in 55 consecutive patients with amiodarone-induced thyrotoxicosis

Amiodarone-induced thyrotoxicosis (AMT) is a life-threatening condition, the appropriate management of which is achieved by identifying its different subtypes. Type 1 AIT develops in patients with underlying thyroid abnormalities and is believed to be due to increased thyroid hormone synthesis and release; Type 2 AIT occurs in patients with a normal thyroid gland and is an amiodarone-induced destructive process of the thyroid. Management differs in the two forms of AIT, since Type 1 usually responds to combined thionamides and potassium perchlorate therapy, while Type 2 is generally responsive to glucocorticoids. Mixed forms, characterized by coexistence of excess thyroid hormone synthesis and destructive phenomena, may require a combination of the two therapeutic regimens. In this cross-sectional prospective study, 55 consecutive untreated patients, whose AIT was subtyped according to clinical and biochemical criteria, were evaluated to assess the specificity of color flow doppler sonography (CFDS) and thyroidal radioiodine uptake (RAIU) in the differential diagnosis of AIT. Sixteen patients (6 men, 10 women, age 66+/-13 yr), who had diffuse or nodular goiter with or without circulating thyroid autoantibodies, were classified as Type 1 AIT; 39 patients (27 men, 12 women, age 65+/-13 yr) with apparently normal thyroids were classified as Type 2 AIT. All Type 1 patients had normal or increased thyroidal vascularity on CFDS, while Type 2 AIT patients had absent vascularity (p<0.0001). Thirteen Type 1 AIT patients had inappropriately normal or elevated thyroidal 3-h and 24-h RAIU values (range 6-37% and 10-58%, respectively), in spite of elevated values of urinary iodine excretion; the remaining 3 patients (two with nodular goiter, one with a thyroid adenoma) had low 3-h and 24-h RAIU values (range 1.1-3.0% and 0.9-4.0%, respectively). The latter patients, who were unresponsive to the combination of methimazole and potassium perchlorate, became euthyroid after the addition of glucocorticoids. Thirty-eight Type 2 AIT patients had low 3-h and 24-h RAIU values (range 0.4-3.7% and 0.2-3.0%, respectively), but one had inappropriately normal 3-h and 24-h RAIU values (6% and 13%, respectively). In conclusion, CFDS can accurately distinguish between Type 1 and Type 2 AIT, and in general the CFDS pattern is concordant with the thyroid RAIU. However, in 4 out of 55 patients (7%) the thyroid RAIU was discrepant, probably reflecting the coexistence of Type 1 and Type 2 AIT. Thus, assessment of both CFDS and RAIU may provide a more accurate subtyping of AIT and help in selecting the appropriate therapy. Finally, in long standing iodine sufficient areas, such as the United States, where the thyroid RAIU is consistently low irrespective of the etiology of the AIT, CFDS offers a rapid and available method to differentiate between Type 1 and Type 2 AIT.

Treatment of type II amiodarone-induced thyrotoxicosis by either iopanoic acid or glucocorticoids: a prospective, randomized study

Amiodarone-induced thyrotoxicosis (AIT) may occur either in the presence of underlying thyroid disease (type I AIT) or in apparently normal thyroid glands (type II AIT). Type II AIT, a destructive thyroiditis, often favorably responds to glucocorticoids. Iopanoic acid (IopAc) is an iodinated cholecystographic agent that inhibits deiodinase activity and reduces the conversion of T(4) toT(3). It has recently been reported that cholecystographic agents restore euthyroidism in patients with type II AIT. We describe the results of a prospective randomized study conducted in 12 patients with type II AIT treated with either iopanoic acid (group A, n = 6) or glucocorticoids (group B, n = 6). Serum free T(3) levels normalized rapidly in both groups after 7 d, from 0.75 +/- 0.20 ng/dl (11.5 +/- 3.1 pmol/liter) to 0.46 +/- 0.10 ng/d (7.1 +/- 1.7 pmol/liter), P < 0.01, and from 0.58 +/- 0.10 ng/dl (9.0 +/- 1.2 pmol/liter) to 0.34 +/- 0.03 ng/dl (5.2 +/- 0.5 pmol/liter), P < 0.003, in groups A and B, respectively (P = NS). Serum free T(4) levels reduced at 6 months in group B [from 2.70 +/- 0.32 ng/dl (35.1 +/- 4.1 pmol/liter) to 1.0 +/- 0.04 ng/dl (13.4 +/- 0.6 pmol/liter), P < 0.0001] but not in group A (from 2.90 +/- 0.6 ng/dl (38.0 +/- 7.5 pmol/liter) to 2.30 +/- 0.4 ng/dl (35.6 +/- 6.1 pmol/liter, P = 0.39; P = 0.005 group B vs. group A). All patients in both groups became euthyroid and had their amiodarone-induced destructive thyroiditis cured as defined by normalization of both serum free T(4) and free T(3) levels, during both drugs therapy. However, patients in group B were cured more rapidly than patients in group A (43 +/- 34 d vs. 221 +/- 111 d, respectively, P < 0.002). This study shows that, albeit both drugs are effective, glucocorticoids are probably the drug of choice for more rapidly curing type II AIT.

Orbital radiotherapy for Graves' ophthalmopathy: useful or useless? Safe or dangerous?

Treatment of Graves' ophthalmopathy does not always provide favorable results. After several decades of efforts, glucocorticoids, orbital radiotherapy (OR) and surgery (orbital decompression) remain the milestones in the management of this disease. OR produce favorable results in about 55-60% of patients. Its effectiveness is increased by the association with systemic glucocorticoids. Recent studies have cast some doubts on its real effectiveness and this is discussed by participants in this Forum. Selection of patients is particularly important to assess treatment outcome, because OR is unlikely to provide beneficial effects in patients with longstanding and inactive eye disease. OR is a safe procedure, with very limited side-effects. It should be used in patients older than 35 years of age. It is recommended that a large, multi-center, prospective, randomized and controlled study with well defined inclusion criteria be carried out to draw sound conclusions on the role of OR in the management of Graves' ophthalmopathy.

Oxidative stress and Graves' ophthalmopathy: in vitro studies and therapeutic implications

Graves' ophthalmopathy (GO) is a disorder of autoimmune origin caused by a complex interplay of endogenous and environmental factors. After recognition of one or more antigens shared by thyroid and orbit, activated T lymphocytes infiltrating the orbit trigger a cascade of events leading to production of cytokines, growth factors and oxygen reactive species. Proliferation of adipocytes and fibroblasts then follows, with an increased synthesis of glycosaminoglycans (GAG), which attract water and cause edema of orbital structures and venous congestion. Proliferation of orbital fibroblasts and adipocytes, both in the retroocular tissue and in the perimysium of extraocular muscles, are among the most important events leading to the increased volume of orbital structures (fibroadipose tissue and extraocular muscles). The contribution of oxygen reactive species to the changes occurring in the orbit is underscored by in vitro studies. Superoxide radical stimulates orbital fibroblasts to proliferate and to produce GAG. Furthermore, hydrogen peroxide induces expression of HLA-DR and heat shock protein-72, involved in antigen recognition and T-lymphocyte recruitment. Cigarette smoking, which is probably the most important environmental factor associated with GO occurrence and maintenance, might also act, among other mechanisms, by enhancing generation of oxygen reactive species and reducing antioxidant production. Substances such as nicotinamide, allopurinol and pentoxifylline reduce superoxide- or hydrogen peroxide-induced proliferation of fibroblasts, GAG production and HLA-DR or HSP-72 expression by GO orbital fibroblasts, possibly through scavenging oxygen free radicals. Two small, non-randomized and/or uncontrolled studies investigated the effects of nicotinamide, allopurinol or pentoxifylline on GO. Favorable results were reported, but data are not fully convincing and the true effectiveness of these agents needs to be verified in randomized, controlled trials enrolling a larger number of patients. It currently seems unlikely that they may find a relevant place in the limited armamentarium available for the management of severe GO.