The effect of carbimazole therapy on interleukin 2, interleukin 2 receptors and free radicals

Current controversies in the management of Graves' hyperthyroidism

Introduction: The management of Graves' disease centers on the use of effective and well-established therapies, namely thionamide antithyroid drugs, radioactive iodine, and thyroidectomy. Optimal treatment strategies are however controversial and vary significantly across centers.Areas covered: This review addresses specific controversies in Graves' disease management including the choice of primary therapy, the approach to women planning pregnancy, and optimal strategies for antithyroid drug and radioiodine therapy.Expert opinion: Important considerations in choosing therapy include treatment efficacy, adverse effects, patient convenience, and resource settings. Recent data suggest that early and effective control of hyperthyroidism is key to improving cardiovascular morbidity and mortality. Studies addressing cancer risk in radioiodine-treated patients face methodological challenges and require clarification in appropriately designed studies. Remission rates with antithyroid drugs are comparable when thionamides are used alone (titration-regimen) or in combination with levothyroxine (block and replace) and can be optimized by extending treatment for at least 12-18 months. Fixed and calculated radioiodine activity regimens are both effective but entail a trade-off between convenience and precision in the administered activity. Optimal preconception strategies are still evolving but ablative treatment in advance of pregnancy offers the most pragmatic means of reducing adverse effects of hyperthyroidism in subsequent pregnancy.

Study of factors that influence the outcome of 131I treatment in hyperthyroidism secondary to nodular goitre

OBJECTIVE

To assess the outcome after ¹³¹I treatment in patients with multinodular (MNG) and nodular toxic goitre (NTG) according to the administered dose and other factors related to the patient, pathology, or previous treatments.

MATERIAL AND METHODS

A retrospective study was conducted on 108 patients (67 MNG and 41 NTG) treated in our department, with a follow-up period of at least 2 years. Development of hypothyroidism and treatment failure were evaluated along with their relationship with the administered dose and other factors such as age, sex, grade of hyperthyroidism, type of goitre, presence of autoimmunity, or previous antithyroid medication.

RESULTS

More than one-third (36.9%) of MNG patients, and even higher proportion of NTG patients (51.2%) developed non-transient hypothyroidism, particularly in those receiving 740MBq (66.7%). No relationship was found with any other variable. The development of early hypothyroidism (before one year) was also not related to any variable. Treatment failure was not related to the dose, but in MNG there was a relationship with male gender, presence of autoimmunity, or previous antithyroid drugs use.

CONCLUSIONS

The high rate of hypothyroidism obtained with high doses of ¹³¹I in hyperthyroidism secondary to nodular goitre treatment suggests that lower doses might be sufficient to control the disease without an increase in treatment failures. Only patients with positive autoimmunity, in previous anti-thyroid medication, and perhaps male gender in MNG might be given higher doses, as the failure rate increases, but further studies are required.

Current and emerging treatment options for Graves' hyperthyroidism

Radioiodine, antithyroid drugs and surgery have been well established therapies for Graves' hyperthyroidism for several decades. However there remain large variations in practice among physicians in the preferred modality and the method of administration. Patient choice and perceptions also play a big role in the choice of treatment. Radioiodine may be given using fixed high doses or by calculated doses following uptake studies. The risks of radioiodine including eye disease and the role of prophylactic steroid therapy are discussed. The commonly used antithyroid drugs include carbimazole, methimazole and propylthiouracil; however a number of other agents have been tried in special situations or in combination with these drugs. The antithyroid drugs may be given in high (using additional levothyroxine in a block-replace regimen) or low doses (in a titration regimen). This review examines the current evidence and relative benefits for these options as well as looking at emerging therapies including immunomodulatory treatments such as rituximab which have come into early clinical trials. The use of antithyroid therapies in special situations is also discussed as well as clinical practice issues which may influence the choices.

The utility of radioiodine uptake and thyroid scintigraphy in the diagnosis and management of hyperthyroidism

BACKGROUND AND OBJECTIVES

The value and practice of thyroid radionuclide imaging in the diagnosis and management of hyperthyroidism is unsettled. Our objectives were to determine the influence of thyroid uptake and scintigraphy on the diagnosis of hyperthyroidism and the prediction of outcome following radioiodine therapy.

PATIENTS AND DESIGN

We reviewed records and scintigraphic studies on 881 hyperthyroid patients carried out between 2000 and 2007. The agreement between the clinical and scintigraphic diagnosis was evaluated by kappa statistics. We determined the relationship between 4-h (123)I uptake and the outcome of (131)I treatment in 626 patients. A multiple logistic regression model was used to determine variables influencing treatment outcome in 1 year.

RESULTS

The diagnostic categories were Graves' disease (GD, n = 383), toxic multinodular goitre (n = 253), solitary toxic nodule (n = 164) and Graves' disease coexisting with nodules (n = 81). The mean age of the patients was 58 +/- 17, (M:F 160:721). There was good agreement between clinical and scintigraph diagnosis (K = 0.60, 95% CI 0.57-0.64, P < 0.001); and they were correctly matched in 74%; mismatched in 6% and indeterminate in 20% of patients. Treatment outcome was not associated with scintigraph diagnosis (P = 0.98) or radioiodine uptake at 4 h (P = 0.2). The use of antithyroid medications before treatment predicted treatment failure (odds ratio 2.0, 95% CI 1.2-3.6, P = 0.01).

CONCLUSION

Thyroid scintigraphy and uptake studies did not influence diagnosis or treatment outcomes in most cases of hyperthyroidism. Our findings in this retrospective study do not justify their routine use. Selective scanning will reduce cost and exposure to radioisotopes without compromising diagnostic accuracy or treatment outcomes.

Effects of antithyroid drugs on radioiodine treatment: systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To determine the effect of adjunctive antithyroid drugs on the risk of treatment failure, hypothyroidism, and adverse events after radioiodine treatment.

DESIGN

Meta-analysis.

DATA SOURCES

Electronic databases (Cochrane central register of controlled trials, Medline, Embase) searched to August 2006 and contact with experts. Review methods Three reviewers independently assessed trial eligibility and quality. Pooled relative risks for treatment failure and hypothyroidism after radioiodine treatment with and without adjunctive antithyroid drugs were calculated with a random effects model.

RESULTS

We identified 14 relevant randomised controlled trials with a total of 1306 participants. Adjunctive antithyroid medication was associated with an increased risk of treatment failure (relative risk 1.28, 95% confidence interval 1.07 to 1.52; P=0.006) and a reduced risk for hypothyroidism (0.68, 0.53 to 0.87; P=0.006) after radioiodine treatment. We found no difference in summary estimates for the different antithyroid drugs or for whether antithyroid drugs were given before or after radioiodine treatment.

CONCLUSIONS

Antithyroid drugs potentially increase rates of failure and reduce rates of hypothyroidism if they are given in the week before or after radioiodine treatment, respectively.

Outcome of radioiodine therapy without, on or 3 days off carbimazole: a prospective interventional three-group comparison

PURPOSE

Carbimazole ameliorates hyperthyroidism but reduces radioiodine uptake and adversely affects the outcome of simultaneous radioiodine therapy. We explored whether withdrawal of carbimazole for 3 days can restore the outcome of radioiodine treatment without concurrent exacerbation of hyperthyroidism. By generating three groups with comparable radioiodine uptake, we also investigated whether the effect of carbimazole depends on the radioiodine uptake.

METHODS

Stratified by a radioiodine uptake >30%, 227 consecutive adult patients were prospectively assigned to radioiodine therapy (target dose 200 Gy) without, on or 3 days off carbimazole. Patients were clinically (Crooks-Wayne score) and biochemically (T(3), fT(4), TSH) followed up after 3, 6 and 12 months. Primary endpoint was outcome 12 months after radioiodine therapy.

RESULTS

A total of 207 patients completed follow-up (toxic nodular goitre, n=117; Graves' disease, n=90). The overall success rate was 71.5%. Patients without and 3 days off carbimazole had similar biochemical (81.4% and 83.3%, respectively; p=0.82) and clinical outcomes [median (range) Crooks-Wayne score 0 (0-16) and 1 (0-10), respectively; p=0.73], which were both higher than in patients on carbimazole [42.6%, p<0.001; Crooks-Wayne score 3 (0-30), p<0.03]. Time to achieve cure was delayed on carbimazole. No changes in thyroid hormone levels occurred after 3 days' discontinuation of carbimazole. Logistic regression revealed that all observed cure rates were independent of entity, sex, age, thyroid volume, radioiodine uptake, radioiodine half-life, fT(4), T(3) and TSH.

CONCLUSION

Patients under carbimazole treatment can be referred for radioiodine therapy after withdrawal of carbimazole for only 3 days. Three days of carbimazole withdrawal is long enough to restore the success of radioiodine therapy and short enough to avoid the risk of exacerbation of hyperthyroidism.

Peripheral parameters of oxidative stress in Graves' disease: the effects of methimazole and 131 iodine treatments

BACKGROUND

Increased oxidative stress, with elevated levels of free radicals, together with diminished antioxidation have been described previously in models of hyperthyroidism and in patients with Graves' disease. However, controversial results have been found about the antioxidant status and its response to treatment.

AIM

To evaluate the antioxidant/oxidant balance in active Graves' disease and the effects of treatment with methimazole (MMI) and 131 iodine (131I).

PATIENTS AND METHODS

We studied 69 hyperthyroid (H) patients, 58 female and 11 male, 16-50 years old; total T3: 8 +/- 2 nmol/l, total T4: 264 +/- 65 nmol/l (all mean +/- SD), TSH: 0.1 +/- 0.1 mIU/l, TSH receptor antibody 41 +/- 21%, highest 131Iodine uptake: 67 +/- 16%. As a control group (C), 19 normal adults were studied.

DESIGN

Parameters evaluated were: tert-butyl hydroperoxide initiated chemiluminiscence (CL), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione peroxidase (GPx) and total reactive antioxidant potential (TRAP).

RESULTS

In patients vs. controls there was an increase in CL levels (6207 +/- 1434 vs. 3000 +/- 851 cpm/mg of haemoglobin, P < 0.001), decrease in SOD (0.4 +/- 0.1 vs. 0.7 +/- 0.2 U/mg prot, P < 0.05; corresponding to 0.15 micro g/ml), CAT (2.8 +/- 0.6 vs. 3.8 +/- 0.7 pmol/mg prot, P < 0.001) and GSH (1.2 +/- 0.4 vs. 2 +/- 0.7 mmol/l erythrocytes, P < 0.05). The decrease in GPx and TRAP did not show significant differences. The parameters were also recorded in 30 patients who became euthyroid after treatment: 20 of them under MMI therapy (2-12 months) and the rest 3-6 months after 131Iodine administration. All the parameters evaluated were normalized after MMI; however, CL levels stayed high after 131I and only CAT and GSH levels returned to normal values.

CONCLUSION

Our results confirm the imbalance of the antioxidant/oxidant status in hyperthyroid patients. MMI treatment was more effective than 131I therapy to improve that balance. We speculate on the benefits of antioxidant therapy administrated together with the habitual treatment of hyperthyroidism, especially in patients after 131I therapy.

Both Th1- and Th2-derived cytokines in serum are elevated in Graves' ophthalmopathy

Increased serum cytokine levels have been reported in patients with autoimmune thyroid disease, but less is known about their levels in patients with Graves' ophthalmopathy (GO). It is not known whether GO is a cell-mediated or humoral autoimmune disease. We investigated whether serum cytokines are elevated in GO patients and whether the cytokines were Th1- or Th2-derived. In addition, elevated cytokines might reflect the activity of GO, and thus we investigated whether cytokine levels could predict the clinical response to orbital radiotherapy. We studied 62 consecutive patients with moderately severe untreated GO and 62 healthy controls, matched for sex, age and smoking habits. Serum concentrations of IL-1RA, sIL-2R, IL-6, sIL-6R, tumour necrosis factor-alpha (TNF-alpha) RI and II and sCD30 were measured using highly sensitive ELISAs, in the patients before and 3 and 6 months after radiotherapy. All patients were euthyroid, with anti-thyroid drugs, before and during the entire study period. All baseline cytokine and cytokine receptor levels were significantly elevated in GO patients compared with healthy controls, except for IL-1RA. The levels did not correlate with parameters of the thyroid disease, nor with the duration, activity or severity of GO. However, backward logistic regression analysis showed that IL-6, sCD30 and TNFalphaRI were able to predict a beneficial response to orbital radiotherapy. We therefore conclude that both Th1- and Th2-derived cytokines are elevated in GO patients compared with its controls. IL-6, sCD30 and TNFalphaRI had some value for predicting therapeutic outcome to orbital irradiation, and may thus reflect active eye disease.

Soluble CD27 in thyroid disorders

We measured the soluble cytokine CD27 in a variety of thyroid disorders. Soluble CD27 was increased in untreated Graves' hyperthyroidism and in euthyroid ophthalmopathy. Levels of sCD27 were normal after the establishment of euthyroidism with propylthiouracil (PTU) or radio iodine in primary hypothyroidism, chronic thyroiditis, and the hyperthyroid and euthyroid phases of subacute thyroiditis. Soluble CD27 is a marker for cellular activation as in Graves' hyperthyroidism, but it is not predictive of the outcome of PTU therapy.

Serum-soluble interleukin-2 receptor levels before and after surgical treatment for Graves' disease

Serum-soluble interleukin-2 receptor (ssIL-2R) is released from its specific affinity membrane receptor on activated T lymphocytes and is detected as a form of the alpha-chain of IL-2R in the peripheral blood. We measured the ssIL-2R levels by enzyme-linked immunosorbent assay in 29 healthy subjects and 39 patients with Graves' disease who were given antithyroid drugs to prepare them for surgical treatment. The preoperative ssIL-2R levels in Graves' patients were significantly higher than those in the healthy controls (681 +/- 387 vs 369 +/- 149 U/ml); in particular, the preoperative levels in hyperthyroid patients were significantly higher than those in euthyroid patients. On the 5th day after thyroid resection, their ssIL-2R levels (560 +/- 296 U/ml) were significantly lower than the preoperative levels. There were no correlations between the preoperative ssIL-2R levels and the immunological parameters such as thyroglobulin antibody, microsomal antibody, and thyroid-stimulating hormone receptor antibody. Thus, we conclude that ssIL-2R levels can be decreased by surgical resection of goiter in Graves' patients whose hyperthyroid status does not respond to the administration of antithyroid drugs, and this may be a useful indicator of immunological status after surgical treatment of Graves' disease.

Soluble IL-2 receptor levels in patients with Graves' ophthalmopathy

In various autoimmune diseases circulating levels of soluble IL-2 receptor (sIL-2R) seem to be related to disease activity. Because reliable parameters of disease activity in Graves' ophthalmopathy are lacking, we measured sIL-2R levels in 47 patients with this disorder. The patients had Graves' disease, but no other immune-mediated diseases, had not yet received specific treatment for their ophthalmopathy and were euthyroid during the entire study period. Twenty-one of the 47 patients (45%) had sIL-2R values above the upper normal limit of 650 U/ml, as established in 20 healthy controls. There were no differences between patients with normal (median 469, range 280-644 U/ml) and elevated (median 946, range 678-1588 U/ml) sIL-2R levels regarding duration or severity of the eye disease (as assessed clinically from the total eye score). However, patients with severely enlarged eye muscles had higher sIL-2R values than patients with less severely enlarged eye muscles on CT scan. Patients with elevated sIL-2R tended to have a higher response rate (71%) to a 3-month course of prednisone, than those with normal levels (46%; P = 0.081). Since a successful outcome of prednisone treatment might be representative for disease activity, the elevated sIL-2R levels seem to reflect active inflammation. Although the practical relevance of this finding in individual patients is limited, it underscores the importance of cell-mediated immune responses in this thyroid-related eye disease.