Anti­livin antibodies in Hashimoto thyroiditis.

INTRODUCTION: Livin belongs to the family of apoptosis inhibitors. High livin expression is observed in malignancies of the gastrointestinal tract, lungs, breast, and kidneys, but it is not present in differentiated adult tissues. In some malignant processes, anti­livin antibodies are present. OBJECTIVES: The aim of the study was to evaluate the prevalence of anti­livin antibodies in Hashimoto thyroiditis, a disease characterized by rapid and widespread thyrocyte apoptosis. PATIENTS AND METHODS: The study comprised 65 women with Hashimoto thyroiditis and the control group of 40 healthy women. In the majority of the patients, clinical manifestations of hypothyroidism were observed; all patients had high levels of serum antithyroid peroxidase antibodies. A solid­phase radioimmunoassay in livin­coated polyethylene tubes using 125I-labeled protein A was used to determine anti-livin antibodies. RESULTS: Significant amounts of anti-livin antibodies were reported in 18 patients (26.8%); 3 patients (4.6%) had borderline antibody levels; while in controls only 1 patient was positive (2.5%, P <0.0001). CONCLUSIONS: In Hashimoto thyroiditis, an autoimmune process is more general and involves numerous autoantibodies including an antibody against apoptosis inhibitor - livin. Anti­livin antibodies cannot serve only as a marker of malignancy because they are also present in autoimmune processes.

Ghrelin and obestatin in thyroid dysfunction.

INTRODUCTION: Ghrelin and obestatin derive from the same precursor. Ghrelin is an energy balance regulator and obestatin's role in metabolic processes cannot be excluded. The aim of this study was to assess plasma ghrelin and obestatin changes in thyroid disorders. MATERIAL AND METHODS: We evaluated plasma ghrelin and obestatin levels in severe hypothyroidism, hypothyroidism after thyreoidectomy and 4-weeks L-thyroxine withdrawal, and in hyperthyroidism. We also re-evaluated plasma ghrelin and obestatin levels in patients with severe hypothyroidism and hyperthyroidism after treatment. RESULTS: Severe hypothyroidism was associated with a reasonably high ghrelin level (p = 0.055) and hyperthyroidism with a significantly lower ghrelin level (p = 0.01) compared to healthy subjects. Ghrelin in hypothyroid patients after L-thyroxine withdrawal did not differ from the control group (p = 0.3). Compared to healthy subjects, obestatin level in hyperthyroidism was decreased (p = 0.03) and did not differ in severe hypothyroidism due to thyroiditis (p = 1) or after L-thyroxine withdrawal (p = 0.6). Ghrelin and obestatin levels correlated positively. Both peptides levels correlated positively with TSH and negatively with free thyroid hormones. In patients with severe hypothyroidism, ghrelin level significantly decreased after treatment (p 〈 0.01) and in hyperthyroid patients significantly increased after treatment (p = 0.04). There were no significant changes in obestatin levels in hypo- or hyperthyroid patients after treatment. CONCLUSIONS: Plasma ghrelin changes and its correlation with TSH and thyroid hormones may indicate a compensatory role of ghrelin in metabolic disturbances associated with thyroid dysfunction. The positive correlation between ghrelin and obestatin levels may suggest a modulatory role of obestatin in these processes.

Technological difficulties in ghrelin and obestatin assays.

In recent years we have performed more than 1,000 radioimmunoassays of ghrelin and obestatin. In these assays, we have encountered several technological obstacles. Another difficulty was the enormous discrepancy of plasma ghrelin results published by different authors. The aim of this article is to comment on these problems. Not all peptides of the hypothalamus and intestines are present in blood circulation. Several neuropeptides do not cross the blood-brain barrier, and several gastrointestinal peptides are present in extremely low concentrations in the blood. That requires time-consuming and laborious extraction. In these procedures, considerable amounts of peptides may be lost. In addition, these peptides are very unstable and prone to enzymatic degradation. This makes it mandatory to add enzymatic inhibitors to plasma samples. The peptides are also unstable in elevated temperatures, hence the assays should be performed in air-conditioned laboratories and the kits should be transported in proper low temperature conditions. Peptides may appear in several isoforms of different biological activity, but antibodies routinely used in these assays are polyclonal and do not differentiate between these forms. This complicates clinical evaluation of the results. To date, there are no international standards of ghrelin, obestatin or other active peptides, probably because of their extreme instability. Because of technological difficulties, the results of peptide assays performed in different scientific research institutions vary greatly and cannot be compared to each other. This disadvantage may be partially diminished by including samples of healthy subjects in each assay run to check whether the peptide concentrations of the patients differ significantly from that of control subjects.

Radioiodine therapy in patients with amiodarone-induced thyrotoxicosis (AIT).

INTRODUCTION: Amiodarone (AM) is frequently used in the therapy of patients with cardiac disorders. However, due to high iodine content, it has side effects on thyroid function. The use of radioiodine therapy (RIT) in amiodarone-induced thyrotoxicosis (AIT) with low radioactive iodine uptake (RAIU) is still controversial. In these patients therapeutic choices for refractory disease include surgery, antithyroid drugs, or glu ocorticosteriods. AIM: The aim of the study was to evaluate the efficacy of RIT in patients presenting AIT and low RAIU in two-year follow-up. PATIENTS AND METHODS: 40 patients (25 men and 15 women) aged from 63 to 83 years (x +/- SD: 66.2 +/- 5.0 years; median: 65 years) treated with RIT were included into the study. In these patients AM therapy was essential for the underlying heart disorder, while surgery, antithyroid drugs or glucocorticosteroids, were contraindicated. Forty seven patients with toxic multinodular goiter (TMNG) (39 women and 8 men), matched for age (67 +/- 12 yr; range 54-89 yr), were enrolled into the study as a comparative group. The diagnostic procedures included baseline thyroid function tests (thyrothropin - TSH, free triiodothyronine - fT3 and free thyroxine - fT4 levels), thyroid autoantibodies measurement (antithyroglobulin autoantibodies - TgAb, antithyroid peroxidase autoantibodies - TPOAb, anti-TSH receptor autoantibodies - TRAb), thyroid ultrasonography, thyroid scintiscan and RAIU assessment. RESULTS: Serum values of TSH, TgAb, TPOAb and TRAb were undetectable in both groups. In patients with AIT fT4 level was 18.7 to 38.7 pmol/l (mean: 27.1 +/- 5.8) and fT3 concentration was 3.9 to 5.6 pmo/l (mean: 5.7 +/- 1.4), while in TMNG patients level of fT4 was 31.5 to 22.2 pmol/l (mean: 25,3 +/- 5,8) and fT3 concentration was 3.8 to 4,2 pmo/l (mean: 4,2 +/- 0,2). Mean RAIU values after 5h and 24h in AIT patients were 2.3 +/- 0.5 and 3.1 +/- 0.9%, while in TMNG patients were 18,0 +/- 3,8 and 35,7 +/- 9,1%, respectively. A significant difference (p<0.001) between 5h and 24h RAIU in AIT compared to TMNG was noted. In all patients with AIT, a dose of 800 MBq of 131I was administered. During two-year-observation recurrence of hyperthyroidism was observed in two patients (5%) with TMNG. These patients received a second radioiodine dose 16.2 +/- 15 months later (the mean re-treatment dose was 735.93 +/- 196.1 MBq). In comparison, none of the patients with AIT required a second 131I dose and only one patient (2.5%) 6 months after ablative 131I dose needed anti-thyroid medication. Transient hypothyroidism was observed in only two patients (5%) with AIH, though was not observed in TMNG. During follow-up time, no sudden deaths in AIT patients were observed; one patient was diagnosed with prostate cancer, and in one patient acute toxic hepatitis after AM occurred. CONCLUSION: RIT may be a safe and useful method of AIT therapy in patients with low RAIU, in whom other treatment methods are contraindicated.

The prevalence of autoantibodies to: myosin, troponin, tropomyosin and myoglobin in patients with circulating triiodothyronine and thyroxine autoantibodies (THAA).

OBJECTIVE: Anti-thyroglobulin, anti-thyroid-peroxidase and anti-TSH receptor antibodies have been observed with high frequency in autoimmune thyroid diseases. Thyroid hormone auto-antibodies (THAA): anti-thyroxine (T4) and anti-triiodothyronine (T3), conversely, have been reported rarely. In both hyperthyroidism and hypothyroidism, patients suffer from muscle weakness and function disorders. The aim of our study was the evaluation of the occurrence rate of autoantibodies targeting muscle proteins in a group of 24 patients with circulating anti-T3 and/or anti-T4 autoantibodies. The control group consisted of 41 healthy blood donors. METHODS: In polyethylene tubes coated with muscle antigens: actin, myosin, myoglobin, troponin and tropomyosin solid-phase radioimmunoassay was performed to detect autoantibodies. A reaction with 125I-labelled staphylococcus protein A was used for the detection of antibodies bound to the antigens on the tubes. RESULTS: We found a high occurrence of antibodies to muscle proteins in patients with THAA. Anti-myoglobin autoantibodies were most frequent (54.2% of subjects), the binding index values was very high and exceeded normal values two to four fold. Anti-myosin autoantibodies were detected in 50% of subjects; anti-troponin autoantibodies in 33.3%, and anti-tropomyosin autoantibody in 3 patients (12.5%). Differences between the patients and the controls were statistically significant. The antibody binding index to actin was low and statistically insignificant. CONCLUSIONS: Our study indicates that muscle protein antibodies, especially to myoglobin, myosin and troponin, are very frequently present in patients with autoimmune thyroid disease and circulating anti-T3 and anti-T4 autoantibodies, as well as in most cases of chronic thyroiditis with clinical symptoms of hypothyroidisms.

Ghrelin concentrations in acromegalic patients in relation to the administered therapy.

OBJECTIVES: Very little is still known about ghrelin in cases of GH hypersecretion. We decided to evaluate whether ghrelin concentrations in acromegalic patients differ according to the administered therapy (surgical and/or with long acting octreotide). We wanted to assess the correlation between serum ghrelin levels and 1) the treatment applied in the past or being applied at the time of our study 2) GH, IGF-1 and insulin concentrations. MATERIAL: Serum ghrelin, GH, IGF-1 and insulin were measured in 42 acromegalic patients who had received surgical and/or long acting octreotide therapy or who hadn't receive any treatment at all. According to the applied treatment, we divided the patients into groups, as follows: 1) LAO/+/, surgery /-/, 2) LAO /+/, surgery /+/, 3) LAO /-/, surgery /-/, 4) LAO /-/, surgery /+/. Ghrelin was also evaluated in 18 control healthy subjects. RESULTS: The difference between mean ghrelin level in the healthy subjects and acromegalic patients was not statistically significant (p=0.08). LAO /-/, surgery /-/ patients showed fasting ghrelin levels indistinguishable from those seen in healthy subjects (p=0.1). There wasn't any statistically significant difference between LAO /-/, surgery /-/ patients and LAO /-/, surgery /+/ group (p=0.14). Serum ghrelin levels in LAO /+/, surgery /+/ group were significantly lower from those observed in LAO /-/, surgery /+/ patients (p=0.006). A similar reduction in ghrelin levels was also found in patients LAO /+/ (both after and without surgery) compared to LAO /-/ patients (both after or without surgery) (p=0.001). Serum ghrelin levels showed a significant negative correlation with IGF-1 concentration and a tendency to a statistically significant correlation with GH in LAO /-/ group (p<0,05). CONCLUSIONS: Ghrelin concentrations were significantly lower in acromegalic patients who had been receiving long acting somatostatin analogue treatment; there was no significant difference in serum ghrelin levels between patients who had and who had not undergone surgery. A significant negative correlation between ghrelin and IGF-1 and a tendency to such correlation between ghrelin and GH was observed in LAO /-/ group of patients.