Therapy of Hyperthyroidism in Pregnancy and Breastfeeding

Docosahexaenoic Acid and Melatonin Prevent Impaired Oligodendrogenesis Induced by Intrauterine Growth Restriction (IUGR)

In this study, our aims were to characterize oligodendrogenesis alterations in fetuses with intrauterine growth restriction (IUGR) and to find therapeutic strategies to prevent/treat them using a novel rabbit in vitro neurosphere culture. IUGR was surgically induced in one uterine horn of pregnant rabbits, while the contralateral horn served as a control. Neural progenitor cells (NPCs) were obtained from pup’s whole brain and cultured as neurospheres mimicking the basic processes of brain development including migration and cell differentiation. Five substances, chosen based on evidence provided in the literature, were screened in vitro in neurospheres from untreated rabbits: Docosahexaenoic acid (DHA), melatonin (MEL), zinc, 3,3′,5-Triiodo-L-thyronine (T3), and lactoferrin (LF) or its metabolite sialic acid (SA). DHA, MEL and LF were further selected for in vivo administration and subsequent evaluation in the Neurosphere Assay. In the IUGR culture, we observed a significantly reduced percentage of oligodendrocytes (OLs) which correlated with clinical findings indicating white matter injury in IUGR infants. We identified DHA and MEL as the most effective therapies. In all cases, our in vitro rabbit neurosphere assay predicted the outcome of the in vivo administration of the therapies and confirmed the reliability of the model, making it a powerful and consistent tool to select new neuroprotective therapies.

Effect of Thyromimetic GC-1 Selective Signaling on Reproductive and Lactational Performance in the Hypothyroid Rat

INTRODUCTION

The potential of the thyroid hormone receptor β (TRβ1) selective analog GC-1 has been widely proven in animal models and humans. However, its effect on the reproductive stage of the female rat has not been evaluated.

METHODS

The effect of the administration of GC-1 or equimolar doses of triiodothyronine (T3) was evaluated on the reproductive performance of the hypothyroid female rat and the indirect effect on pup thyroid status, weight, and survival.

RESULTS

Hypothyroidism reduced the number of embryos implanted in the uterus, whereas T3 and GC-1 treatment in hypothyroid females reestablished the number of implanted embryos to normal. Initiation of labor was delayed by hypothyroidism, and T3 replacement treatment reinstated the normal timing of parturition. The administration of GC-1 alone to the lactating mother did not affect pup survival, weight, or thyroidal status.

CONCLUSIONS

Our findings show the differential effect of thyroid hormone selective signaling during gestation and the indirect exposure of the pups; we also emphasize the plausible use of GC-1 for treatment of hypothyroid mothers during the lactation period.

[Thyroid dysfunction in pregnancy. Consensus document. Andalusian Society of Endocrinology and Nutrition (SAEN)]

A position statement on the diagnosis and treatment of thyroid dysfunction in pregnancy has been agreed on behalf of The Sociedad Andaluza de Endocrinología y Nutrición (SAEN), based on a review of the literature to date and all good clinical practice guidelines. The document is set out in different sections as regards the diagnosis and treatment of, overt and subclinical hypo- and hyperthyroidism, isolated hypothyroxinaemia and postpartum thyroiditis. It also justifies the implementation of universal screening for thyroid dysfunction in pregnancy, and provides practitioners who care for these patients with tool for rational decision making.

[Perioperative treatment for the urgent orbital decompression surgery in a 30-weeks pregnant woman with Graves' orbitopathy]

Thyroid ophthalmopathy is a rare extra-thyroid complication usually associated with Graves' disease. This disease can occur in the euthyroid pregnant patient. Graves' orbitopathy is characterized by eyelid retraction, proptosis, extraocular muscle dysfunction, and periorbital edema. In some cases an emergency surgical repair may be required to avoid irreversible vision loss. We present the case of a 35-year-old woman in her 30th gestational week, who suffered from Graves' ophthalmopathy, severe exophthalmia, and visual acuity decrease. Following consultations among anesthesiologists, ophthalmologists, maxillofacial surgeons, endocrinologists, obstetricians and the patient, it was decided to perform a surgical orbital wall decompression. The anesthetic and perioperative implications associated with gestational age and the considerations for this surgical procedure, and how to avoid increasing intraocular pressure are discussed.

Propylthiouracil increases sodium/iodide symporter gene expression and iodide uptake in rat thyroid cells in the absence of TSH

BACKGROUND

Propylthiouracil (PTU) and methimazole (MMI) are drugs that are widely used to treat Graves' disease. Although both exert an antithyroid effect primarily by blocking thyroid peroxidase activity, their molecular structure and other actions are different. We hypothesized that PTU and MMI may have differential effects on thyroid-specific gene expression and function.

METHODS

The effects of PTU and MMI on thyroid-specific gene expression and function were examined in rat thyroid FRTL-5 cells using DNA microarray, reverse transcriptase (RT)-polymerase chain reaction (PCR), real-time PCR, Western blot, immunohistochemistry, and radioiodine uptake studies.

RESULTS

DNA microarray analysis showed a marked increase in sodium/iodide symporter (NIS) gene expression after PTU treatment, whereas MMI had no effect. RT-PCR and real-time PCR analysis revealed that PTU-induced NIS mRNA levels were comparable to those elicited by thyroid-stimulating hormone (TSH). PTU increased 5'-1880-bp and 5'-1052-bp activity of the rat NIS promoter. While PTU treatment also increased NIS protein levels, the size of the induced protein was smaller than that induced by TSH, and the protein localized predominantly in the cytoplasm rather than the plasma membrane. Accumulation of (125)I in FRTL-5 cells was increased by PTU stimulation, but this effect was weaker than that produced by TSH.

CONCLUSIONS

We found that PTU induces NIS expression and iodide uptake in rat thyroid FRTL-5 cells in the absence of TSH. Although PTU and MMI share similar antithyroid activity, their effects on other thyroid functions appear to be quite different, which could affect their therapeutic effectiveness.