Patologia tiroideia e infertilidade feminina

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Biomarqueurs pronostiques dans le cancer de la prostate : mieux prédire pour mieux traiter

Le cancer de la prostate (CP) est le cancer le plus fréquemment diagnostiqué en Amérique du Nord et est au troisième rang en termes de létalité chez les hommes. Suite aux traitements de première ligne, 20 à 30% des patients diagnostiqués avec un cancer localisé auront une récidive biochimique de la maladie. La déplétion androgénique mène fréquemment au développement du stade de résistance à la castration (RC). Ce dernier est associé avec une augmentation de la morbidité (métastases osseuses) et de la mortalité avec une survie moyenne inférieure à deux ans. L’évolution du CP est très hétérogène dans la population et il n’existe actuellement aucun biomarqueur pronostique permettant d’identifier les patients à risque de récurrence biochimique, de métastases osseuses et de développement d’une résistance à la castration. De nombreuses études ont démontré que les cytokines inflammatoires IL-6 et IL-8 jouent un rôle dans la pathogénèse du CP, notamment dans le développement de la résistance à la castration. Par ailleurs, les niveaux sériques élevés de ces cytokines ont été associés à un mauvais pronostic. Précédemment, notre laboratoire a démontré in vitro que la protéine IKKε entraîne une augmentation de la sécrétion de ces cytokines dans les cellules du CP et qu’elle est exprimée davantage dans les tissus de cancers plus avancés. Le premier objectif du présent mémoire fut d’évaluer dans des tissus humains la corrélation d’IKKε, IL-6 et IL-8 avec des paramètres cliniques. Nos résultats soulignent le potentiel d’IKKε comme biomarqueur tissulaire pronostique de récurrence biochimique et de métastases osseuses. Nous n’avons trouvé aucune association entre IL-6/IL-8 et les paramètres cliniques inclus dans l’étude. Le second objectif de ce projet fut d’évaluer la coexpression de ces trois molécules dans l’épithélium du CP. Nos résultats confirment les observations in vitro en mettant en évidence une forte association entre l’expression d’IKKε, IL-6 et IL-8. Le troisième objectif fut d’évaluer la relation entre les niveaux sériques et tissulaires d’IL-6 et d’IL-8. Aucune relation significative n’a été établie, suggérant que les cytokines sériques ne sont pas uniquement d’origine prostatique. En conclusion, mon projet de maîtrise aura permis de préciser le potentiel d’IKKε comme biomarqueur tissulaire pronostique et de valider pour la première fois dans des tissus humains sa co-expression avec les cytokines IL-6 et IL-8, dont le rôle dans la pathogénèse de la maladie est bien établi. Une étude plus exhaustive des voies de signalisation d’IKKε reste d’intérêt pour élucider notamment les mécanismes par lesquels IKKε stimule la production de cytokines et par quels moyens cette protéine pourrait être impliquée dans le développement d’un état résistant à la castration.

Quality of life compared during pharmacological treatments and clinical monitoring for non-localized prostate cancer: a randomized controlled trial

To investigate the effects of different management strategies for non-localized prostate cancer on men's quality of life and cognitive functioning. Men with prostate cancer were randomly assigned to one of four treatment arms: leuprorelin, goserelin, cyproterone acetate (CPA), or close clinical monitoring. In a repeated-measures design, men were assessed before treatment (baseline) and after 6 and 12 months of treatment. A community comparison group of men of the same age with no prostate cancer participated for the same length of time. The men were recruited from public and private urology departments from university teaching hospitals. All those with prostate cancer who were eligible for hormonal therapy had no symptoms requiring immediate therapy. In all, 82 patients were randomized and 62 completed the 1-year study, and of the 20 community participants, 15 completed the study. The main outcome measures were obtained from questionnaires on emotional distress, existential satisfaction, physical function and symptoms, social and role function, subjective cognitive function, and sexual function, combined with standard neuropsychological tests of memory, attention, and executive functions. Sexual dysfunction increased for patients on androgen-suppressing therapies, and emotional distress increased in those assigned to CPA or close clinical monitoring. Compared with before treatment there was evidence of an adverse effect of leuprorelin, goserelin, and CPA on cognitive function. In deciding the timing of androgen suppression therapy for prostate cancer, consideration should be given to potential adverse effects on quality of life and cognitive function.

Selenium binding protein 1 in ovarian cancer

Selenium binding protein I (SELENBP1) was identified to be the most significantly down-regulated protein in ovarian cancer cells by a membrane proteome profiling analysis. SELENBP1 expression levels in 4 normal ovaries, 8 benign ovarian tumors, 12 borderline ovarian tumors and 141 invasive ovarian cancers were analyzed with immunohistochemical assay. SELENBP1 expression was reduced in 87% cases of invasive ovarian cancer (122/141) and was significantly reduced in borderline tumors and invasive cancers (p < 0.001). Cox multivariate analysis within the 141 invasive cancer tissues showed that SELENBP1 expression score was a potential prognostic indicator for unfavorable prognosis of ovarian cancer (hazard ratio [HR], 2.18; 95% CI = L22-190; p = 0.009). Selenium can disrupt the androgen pathway, which has been implicated in modulating SELENBP1 expression. We investigated the effects of selenium and androgen on normal human ovarian surrace epithelial (HOSE) cells and cancer cells. Interestingly, SELENBP1 mRNA and protein levels were reduced by androgen and elevated by selenium treatment in the normal HOSE cells, whereas reversed responses were observed in the ovarian cancer cell lines. These results suggest that changes of SELENBP1 expression in malignant ovarian cancer are an indicator of aberration of selenium/androgen pathways and may reveal prognostic information of ovarian cancer. (c) 2005 Wiley-Liss, Inc.

Plasma steroids and steroid-binding capacity in male semelparous dasyurid marsupials (Phascogale tapoatafa) that survive beyond the breeding season in captivity

The semelparous dasyurids display a unique life history, in that all males die within a few weeks of the completion of the breeding season. Studies of several semelparous species have revealed that the male die-off is stress-related, and accompanied by increased plasma androgen and cortisol levels and decreased corticosteroid binding capacity, resulting in suppression of immune and inflammatory responses. This study examines the endocrine profile of male brush-tailed phascogales (Phascogale tapoatafa) that survive beyond the breeding season in captivity. Plasma cortisol, corticosteroid binding globulin and albumin levels were monitored in both males and females and steroid partitioning calculated. Captive males surviving beyond the breeding season did not show the elevation in plasma cortisol and decrease in corticosteroid binding capacity reported in wild males. Plasma albumin concentrations also remained constant during the sampling period. These data indicate that captive males do not undergo the same stress response described in wild populations. (c) 2006 Elsevier Inc. All rights reserved.

Resistance training and reduction of treatment side effects in prostate cancer patients

Purpose: To examine the effect of progressive resistance training on muscle function, functional performance, balance, body composition, and muscle thickness in men receiving androgen deprivation for prostate cancer. Methods: Ten men aged 59-82 yr on androgen deprivation for localized prostate cancer undertook progressive resistance training for 20 wk at 6- to 12-repetition maximum (RM) for 12 upper- and lower-body exercises in a university exercise rehabilitation clinic. Outcome measures included muscle strength and muscle endurance for the upper and lower body, functional performance (repeated chair rise, usual and fast 6-m walk, 6-m backwards walk, stair climb, and 400-m walk time), and balance by sensory organization test. Body composition was measured by dual-energy x-ray absorptiometry and muscle thickness at four anatomical sites by B-mode ultrasound. Blood samples were assessed for prostate specific antigen (PSA), testosterone, growth hormone (GH), cortisol, and hemoglobin. Results: Muscle strength (chest press, 40.5%; seated row, 41.9%; leg press, 96.3%; P < 0.001) and muscle endurance (chest press, 114.9%; leg press, 167.1%; P < 0.001) increased significantly after training. Significant improvement (P < 0.05) occurred in the 6-m usual walk (14.1%), 6-m backwards walk (22.3%), chair rise (26.8%), stair climbing (10.4%), 400-m walk (7.4%), and balance (7.8%). Muscle thickness increased (P < 0.05) by 15.7% at the quadriceps site. Whole-body lean mass was preserved with no change in fat mass. There were no significant changes in PSA, testosterone, GH, cortisol, or hemoglobin. Conclusions: Progressive resistance exercise has beneficial effects on muscle strength, functional performance and balance in older men receiving androgen deprivation for prostate cancer and should be considered to preserve body composition and reduce treatment side effects.

Interactions between behaviour and plasma steroids within the scramble mating system of the promiscuous green turtle, Chelonia mydas

We measured plasma androgen (combined testosterone and 5 alpha-dihydrotestosterone) (A) and corticosterone (B) in the promiscuous green turtle (Chelonia mydas) during courtship in the southern Great Barrier Reef. This study examined if reproductive behaviors and intermale aggression induced behavioral androgen and adrenocortical responses in reproductively active male and female green turtles. Associations between reproductive behavior and plasma steroids were investigated in green turtles across the population and within individuals. Levels across a range of both asocial and social behaviors were compared including (a) free swimming behavior; (b) initial courtship interactions; (c) mounted behavior (male and female turtles involved in copulatory activities); (d) intermale aggression (rival males that physically competed with another male turtle or mounted males recipient to these aggressive interactions); and (e) extensive courtship damage (male turtles that had accumulated excessive courtship damage from rival males). Behavioral androgen responses were detected in male turtles, in that plasma A was observed to increase with both attendant and mounted behavior. Male turtles who had been subjected to intermale aggression or who had accumulated severe courtship damage exhibited significantly lower plasma A than their respective controls. No pronounced adrenocortical response was observed after either intermale aggression or accumulation of extensive courtship damage. Female turtles exhibited a significant increase in plasma B during swimming versus mounted behavior, but no change in plasma A. We discuss our results in terms of how scramble polygamy might influence behavioral androgen interactions differently from more typical combative and territorial forms Of male polygamy. (C) 1999 Academic Press.

The control of mitosis in mammalian tissues

The question of which factors are central in determining whether a cell will undertake a new round of mitosis or will decycle has been examined in the isolated thymic lymphocyte model. Such cell populations possess both in vivo and in vitro a subpopulation of quiescent lymphoblasts which may be induced to reinitiate their mitotic programme. In the intact animal the major determinant of proliferative activity is the plasma ionised calcium concentration. However it has been established in culture that a variety of hormones, ions, cyclic nucleotides, plant lectins and ionophores may like calcium elicit a mitogenic response. These agents do not appear however to initiate DNA synthesis in an identical fashion. Rather there are two distinct intracellular mitogenic axes. The first axis includes a number of adenylate cyclase stimulants, cyclic AMP, phosphodiesterase inhibitors and magnesium ions. It was found that all these mitogens required extracellular magnesium ions to exhibit their stimulatory capacity. This dichotomy in mitogenic activity was further emphasised by the observation that these mitogens are all inhibited by testosterone, whilst the magnesium-independent mitogens were insensitive to this androgen. Indeed this second group of stimulatory factors required the presence of calcium ions in the extracellular milieu for activity, and were, in contrast to the magnesium-dependent mitogens inhibited by the presence of oestradiol in the culture. By examining the interrelationships between these various mitogens and inhibitors it has been possible to propose a mechanism to describe the activation process in the thymocyte. Studies of the metabolism of cyclic nucleotides, membrane potential and transmembrane ion fluxes indicate that there may be a complex relationship between membrane fluidity, ion balance and cyclic nucleotide levels which may individually or in concert promote the initiation of DNA synthesis. A number of possible mechanisms are discussed to account for these observations.

Calcitonin gene-related peptide, adrenomedullin and flushing

Administration of calcitonin gene-related peptide (CGRP) or adrenomedullin (AM) can cause facial flushing, suggesting that the peptides may be important in hot flushes experienced particularly by post-menopausal women. Five studies have measured plasma CGRP concentrations in post-menopausal women who suffer from flushes; all demonstrated elevations of between 170% and 320% over control. Three of the studies showed a temporal relationship between flushes and CGRP elevation. A further study has shown that CGRP is elevated in the urine of women who suffer from flushes. Only a single study has investigated flushes in pre-menopausal women; no elevation of CGRP was observed. Flushes are also experienced by men undergoing androgen deprivation therapy. Whilst one study failed to find any increase in CGRP in the urine of these individuals, a small study has identified an increase in plasma CGRP. No studies have investigated plasma AM or the related peptide, intermedin/AM2. Overall, there is good evidence to show that flushes in post-menopausal women are accompanied by an increase in CGRP. CGRP could act centrally on the thermoregulatory centre of the hypothalamus as well as peripherally to cause vasodilation and sweating. However, it remains to be demonstrated that the elevated CGRP causes flushes. Recently developed CGRP antagonists provide an opportunity to test this hypothesis. If they are successful, they may represent a useful alternative to oestrogen replacement therapy.

A novel role for the adipokine visfatin/pre-B cell colony-enhancing factor 1 in prostate carcinogenesis

Adipose tissue is now well established as an endocrine organ and multiple hormones termed ‘adipokines’ are released from it. With the rapidly increasing obese population and the increased risk mortality from prostate cancer within the obese population we looked to investigate the role of the adipokine visfatin in LNCaP and PC3 prostate cancer cell lines. Using immunohistochemistry and immunocytochemistry we demonstrate visfatin expression in LNCaP (androgen-sensitive) and PC3 (androgen-insensitive) human prostate cancer cell lines as well as human prostate cancer tissue. Additionally, we show that visfatin increases PC3 cell proliferation and demonstrate the activation of the MAPKs ERK-1/2 and p38. Moreover we also demonstrate that visfatin promotes the expression and activity of MMP-2/9 which are important proteases involved in the breakdown of the extracellular matrix, suggesting a possible role for visfatin in prostate cancer metastases. These data suggest a contributory and multifunctional role for visfatin in prostate cancer progression, with particular relevance and emphasis in an obese population.

Clonal composition of human adamantinomatous craniopharyngiomas and somatic mutation analyses of the patched (PTCH), Gsα and Gi2α genes

Craniopharyngioma is the most common childhood tumor and thought to arise from embryonic remnants of Rathke's pouch. The paucity of published data on the molecular basis of these tumors prompted us to examine 22 adamantinomatous craniopharyngiomas looking for genetic abnormalities. Using the X-linked polymorphic androgen receptor gene as a tool for X-chromosome inactivating analysis, we found that a subset of craniopharyngiomas are monoclonal and therefore are probably due to acquired somatic genetic defects. Thus, we investigated these tumours for mutations within three candidate genes, Gsα, Gi2α and patched (PTCH). Using single stranded conformational polymorphism (SSCP), denaturing gradient gel electrophoresis and direct sequencing, the presence of somatic mutations in these genes could not be demonstrated in any tumor. Our data indicate that a subset of craniopharyngiomas are monoclonal and the mutations in the PTCH, Gsα, and Gi2α contribute little if any to cranipharyngioma development.

Dehdyroepiandrosterone sulfate directly activates protein kinase C-β to increase human neutrophil superoxide generation

Dehydroepiandrosterone sulfate (DHEAS) is the most abundant steroid in the human circulation and is secreted by the adrenals in an age-dependent fashion, with maximum levels during the third decade and very low levels in old age. DHEAS is considered an inactive metabolite, whereas cleavage of the sulfate group generates dehydroepiandrosterone (DHEA), a crucial sex steroid precursor. However, here we show that DHEAS, but not DHEA, increases superoxide generation in primed human neutrophils in a dose-dependent fashion, thereby impacting on a key bactericidal mechanism. This effect was not prevented by coincubation with androgen and estrogen receptor antagonists but was reversed by the protein kinase C inhibitor Bisindolylmaleimide 1. Moreover, we found that neutrophils are unique among leukocytes in expressing an organic anion-transporting polypeptide D, able to mediate active DHEAS influx transport whereas they did not express steroid sulfatase that activates DHEAS to DHEA. A specific receptor for DHEAS has not yet been identified, but we show that DHEAS directly activated recombinant protein kinase C-ß (PKC-ß) in a cell-free assay. Enhanced PKC-ß activation by DHEAS resulted in increased phosphorylation of p47phox, a crucial component of the active reduced nicotinamide adenine dinucleotide phosphate complex responsible for neutrophil superoxide generation. Our results demonstrate that PKC-ß acts as an intracellular receptor for DHEAS in human neutrophils, a signaling mechanism entirely distinct from the role of DHEA as sex steroid precursor and with important implications for immunesenescence, which includes reduced neutrophil superoxide generation in response to pathogens.

Endocrine regulation of dynamic communication signals in gymnotiform fish

Communication signals are shaped by the opposing selection pressures imposed by predators and mates. A dynamic signal might serve as an adaptive compromise between an inconspicuous signal that evades predators and an extravagant signal preferred by females. Such a signal has been described in the gymnotiform electric fish, Brachyhypopomus gauderio, which produces a sexually dimorphic electric organ discharge (EOD). The EOD varies on a circadian rhythm and in response to social cues. This signal plasticity is mediated by the slow action of androgens and rapid action of melanocortins. My dissertation research tested the hypotheses that (1) signal plasticity is related to sociality levels in gymnotiform species, and (2) differences in signal plasticity are regulated by differential sensitivity to androgen and melanocortin hormones. To assess the breadth of dynamic signaling within the order Gymnotiformes, I sampled 13 species from the five gymnotiform families. I recorded EODs to observe spontaneous signal oscillations after which I injected melanocortin hormones, saline control, or presented the fish with a conspecific. I showed that through the co-option of the ancient melanocortin pathway, gymnotiforms dynamically regulate EOD amplitude, spectral frequency, both, or neither. To investigate whether observed EOD plasticities are related to species-specific sociality I tested four species; two territorial, highly aggressive species, Gymnotus carapo and Apteronotus leptorhynchus, a highly gregarious species, Eigenmannia cf. virescens , and an intermediate short-lived species with a fluid social system, Brachyhypopomus gauderio. I examined the relationship between the androgens testosterone and 11-ketotestosterone, the melanocortin α-MSH, and their roles in regulating EOD waveform. I implanted all fish with androgen and blank silicone implants, and injected with α-MSH before and at the peak of implant effect. I found that waveforms of the most territorial and aggressive species were insensitive to hormone treatments; maintaining a static, stereotyped signal that preserves encoding of individual identity. Species with a fluid social system were most responsive to hormone treatments, exhibiting signals that reflect immediate condition and reproductive state. In conclusion, variation in gymnotiform signal plasticity is hormonally regulated and seems to reflect species-specific sociality.