Iodide excess regulates its own efflux: a possible involvement of pendrin.

Adequate iodide supply and metabolism are essential for thyroid hormones synthesis. In thyrocytes, iodide uptake is mediated by the sodium-iodide symporter, but several proteins appear to be involved in iodide efflux. Previous studies demonstrated that pendrin is able to mediate apical efflux of iodide in thyrocytes. Acute iodide excess transiently impairs thyroid hormone synthesis, a phenomenon known as the Wolff-Chaikoff effect. Although the escape from this inhibitory effect is not completely understood, it has been related to the inhibition of sodium-iodide symporter-mediated iodide uptake. However, the effects of iodide excess on iodide efflux have not been characterized. Herein, we investigated the consequences of iodide excess on pendrin abundance, subcellular localization, and iodide efflux in rat thyroid PCCl3 cells. Our results indicate that iodide excess increases pendrin abundance and plasma membrane insertion after 24 h of treatment. Moreover, iodide excess increases pendrin half-life. Finally, iodide exposure also increases iodide efflux from PCCl3 cells. In conclusion, these data suggest that pendrin may have an important role in mediating iodide efflux in thyrocytes, especially under conditions of iodide excess.

Thyroid hormones for euthyroid patients with simple goiter growing over time: a survey of European thyroid specialists.

BACKGROUND: Treatment of simple goiter (SG) growing over time with thyroid hormone (TH) therapy is discouraged by international guidelines. PURPOSE: To ascertain views of European thyroid specialists about TH treatment for euthyroid patients with growing SG and explore associations with management choice. METHODS: Online survey on the use of TH for growing SG among thyroid experts from 28 European countries. RESULTS: The response rate was 31.5% (5430/17,247). Most respondents were endocrinologists. Twenty-eight percent asserted that TH therapy may be indicated in euthyroid patients with a growing SG. National and regional differences were noted, from 7% of positive responses in The Netherlands to 78% in Czech Republic (p < 0.0001). TH was more frequently prescribed by respondents over 40 years old (OR 1.77, 2.13, 2.41 if 41-50, 51-60, >60, respectively), and working in areas of former iodine insufficiency (OR 1.24, 95% CI 1.03-1.50). TH was less frequently prescribed by endocrinologists (OR 0.77, 95% CI 0.62-0.94) and respondents working in Southern Europe (OR 0.40, 95% CI 0.33-0.48), Northern Europe (OR 0.28, 95% CI 0.22-0.36) and Western Asia (OR 0.16, 95% CI 0.11-0.24) compared to Western Europe. Associations with respondents' sex, country, availability of national thyroid guidelines, and gross national income per capita were absent or weak. CONCLUSIONS: Almost a third of European thyroid specialists support treating SG with TH, contrary to current guidelines and recommendations. This calls for urgent attention.

Urinary shedding of leptospires and presence of Leptospira antibodies in healthy dogs from Upper Bavaria.

Leptospirosis is classified as a re-emerging zoonotic disease with global impor- tance. The aim of this study was to determine urinary shedding of leptospires in healthy dogs and to identify the shedded leptospire species. Furthermore, antibody presence against leptospires was evaluated. In a prospective study urine samples of 200 healthy dogs from Upper Bavaria were randomly collected and evaluated by real-time polymerase chain reaction (PCR) specific for the lipL32 gene of pathogenic Leptospira (L) spp. Positive samples were further character- ized via multilocus sequence typing (MLST) to identify the Leptospira species. Microagglutination test (MAT) was performed to determine serum antibody titers. Three of 200 urine samples were found to be PCR-positive resulting in a urinary shedding prevalence of 1.5% (95% confidence interval 0.3-4.5%). All three dogs had been vaccinated before with a bivalent vaccine, covering the serogroups Canicola and lcterohaemorrhagiae. One dog shed leptospires of the species L. borgpetersenii, and two of the species L. interrogans. Of all dogs, 17.0% had antibody titers ≥ 1:100, and 3.5% titers ≥ 1:400 to serovars of non-vaccinal sero- groups. Healthy dogs that shed leptospires represent a possible risk for humans and other animals. The study emphasizes the importance of general hygiene measures in veterinary practice while handling urine of all dogs, and the use of vaccines that protect against a broader range of serogroups and that prevent urinary shedding.