Evaluation of renal perfusion in hyperthyroid cats before and after radioiodine treatment

Background: Hyperthyroidism and chronic kidney disease (CKD) are common in elderly cats. Consequently, both diseases often occur concurrently. Furthermore, renal function is affected by thyroid status. Because changes in renal perfusion play an important role in functional renal changes in hyperthyroid cats, investigation of renal perfusion may provide novel insights. Objectives: To evaluate renal perfusion in hyperthyroid cats with contrast-enhanced ultrasound (CEUS). Animals: A total of 42 hyperthyroid cats was included and evaluated before and 1 month after radioiodine treatment. Methods: Prospective intrasubject clinical trial of contrast-enhanced ultrasound using a commercial contrast agent (SonoVue) to evaluate renal perfusion. Time-intensity curves were created, and perfusion parameters were calculated by off-line software. A linear mixed model was used to examine differences between pre-and post-treatment perfusion parameters. Results: An increase in several time-related perfusion parameters was observed after radioiodine treatment, indicating a decreased blood velocity upon resolution of the hyperthyroid state. Furthermore, a small post-treatment decrease in peak enhancement was present in the renal medulla, suggesting a lower medullary blood volume. Conclusions and Clinical Importance: Contrast-enhanced ultrasound indicated a higher cortical and medullary blood velocity and higher medullary blood volume in hyperthyroid cats before radioactive treatment in comparison with 1-month post-treatment control

Thyroid status modulates T lymphoma growth via cell cycle regulatory proteins and angiogenesis

We have shown in vitro that thyroid hormones (THs) regulate the balance between proliferation and apoptosis of T lymphoma cells. The effects of THs on tumor development have been studied, but the results are still controversial. Herein, we show the modulatory action of thyroid status on the in vivo growth of T lymphoma cells. For this purpose, euthyroid, hypothyroid, and hyperthyroid mice received inoculations of EL4 cells to allow the development of solid tumors. Tumors in the hyperthyroid animals exhibited a higher growth rate, as evidenced by the early appearance of palpable solid tumors and the increased tumor volume. These results are consistent with the rate of cell division determined by staining tumor cells with carboxyfluorescein succinimidyl ester. Additionally, hyperthyroid mice exhibited reduced survival. Hypothyroid mice did not differ significantly from the euthyroid controls with respect to these parameters. Additionally, only tumors from hyperthyroid animals had increased expression levels of proliferating cell nuclear antigen and active caspase 3. Differential expression of cell cycle regulatory proteins was also observed. The levels of cyclins D1 and D3 were augmented in the tumors of the hyperthyroid animals, whereas the cell cycle inhibitors p16/INK4A (CDKN2A) and p27/Kip1 (CDKN1B) and the tumor suppressor p53 (TRP53) were increased in hypothyroid mice. Intratumoral and peritumoral vasculogenesis was increased only in hyperthyroid mice. Therefore, we propose that the thyroid status modulates the in vivo growth of EL4 T lymphoma through the regulation of cyclin, cyclin-dependent kinase inhibitor, and tumor suppressor gene expression, as well as the stimulation of angiogenesis.Fil: Sterle, Helena Andrea. Pontificia Universidad Católica Argentina ; ArgentinaFil: Valli, Eduardo. Pontificia Universidad Católica Argentina ; ArgentinaFil: Cayrol, Maria Florencia. Pontificia Universidad Católica Argentina ; ArgentinaFil: Paulazo, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Martinel Lamas, Diego José. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Díaz Flaqué, María Celeste. Pontificia Universidad Católica Argentina ; ArgentinaFil: Klecha, Alicia Juana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Colombo, L.. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología ; ArgentinaFil: Medina, Vanina Araceli. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cremaschi, Graciela Alicia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Pontificia Universidad Católica Argentina ; ArgentinaFil: Barreiro Arcos, María Laura. Pontificia Universidad Católica Argentina ; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentin

Hyperthyroidism in cats, part II : scintigraphic diagnosis and radioiodine treatment

In the second part of this review article, the diagnostic aspects of thyroid scintigraphy are discussed, with major emphasis on hyperthyroidism, followed by an overview of radioiodine treatment

Hyperthyroidism in cats, part I : anatomy, physiology, pathophysiology, diagnosis and imaging

In the first part of this review article, thyroid anatomy, physiology and pathophysiology are reviewed to continue more specifically on hyperthyroidism, the most common thyroid disorder in cats. The diagnostic work-up of this disorder is discussed with emphasis on thyroid gland imaging. Scintigraphy is most commonly used and best suited to assess thyroid function, which will be discussed extensively in the second part of this review article. All other available imaging modalities do not offer a functional assessment and are therefore of limited use in the diagnosis and evaluation of hyperthyroidism

Thyroid hormone receptors and ligand, tissue distribution and sexual behavior

The thyroid hormones (THs) triiodothyronine (T3) and tetraiodothyronine, or thyroxine (T4), not only dramatically impact on development and differentiation, but also on the sexual and reproductive function. There is large body of literature, in fact, on the effects of THs on the reproductive function in both humans (Poppe and Velkeniers, 2004; Wajner et al., 2009) and animals (Hapon et al., 2010; Nelson et al., 2011). For a long time the gonads were thought to be unresponsive to THs, but TH receptors (TR) were discovered in rat (Jannini et al., 1990; Palmero et al., 1988) and then in human testis (Jannini et al., 2000). In women, the association of menstrual disturbance with thyroid disease was described as early as 1840 by von Basedow, but the discovery of TRs in the ovary was carried out at the end of last century (Wakim et al., 1994b). Therefore, the link between thyroid and reproductive function was well established. Since then, research has shown that thyroid dysfunction is associated with an adverse effect on fertility, both in men (Wagner et al., 2009) and women (Dittrich et al., 2011). There is also evidence that THs can affect the sex steroid hormone axis (Bagamasbad and Denver, 2011), consequently sexual hormones and the pituitary gland can mediate the action of THs on the reproductive physiology. While the effects of THs on fertility have been widely studied, little is known about their influence on sexual function. In the last few years, an increasing number of evidences have shown the influence of THs on male sexual function, particularly on ejaculation control as well on desire and erectile function (Carani et al., 2005; Corona et al., 2012b; Di Sante et al., 2016). The female sexual function and the relationship with thyroid function is still less studied. Furthermore, studies conducted on animals have shown the presence of TRs in the male (Carosa et al., 2010) and female genitalia (Rodriguez-Castelan et al., 2017). Moreover, knockout mice for TRs showed alterations in sexual behavior (Dellovade et al., 2000). The purpose of this review is to summarize and discuss the available data on the influence of THs on male and female sexual function to understand the molecular mechanisms of the influence of the thyroid gland on sexual behavior and function