Proteína moduladora de la actividad del receptor de aril hidrocarburos (AIP): genética, bioquímica e impacto clínico / Aryl hydrocarbon receptor interacting protein (AIP): genetics, biochemistry and clinical impact

El gen AIP (proteína moduladora de la actividad del receptor de aril hidrocarburos) se localiza en la región 11q13.2 y codifica para una proteína de 330 aminoácidos que interactúa con el factor de transcripción AhR (receptor para aril hidrocarburos). Las mutaciones en este gen se han asociado con adenomas pituitarios aislados de tipo familiar (APAF). Se caracterizan por una presentación temprana (alrededor de 20 años), por lo regular producen hormona de crecimiento y/o prolactina, tienen un comportamiento clínico agresivo y poca respuesta a análogos de somatostatina.

The AIP gene (aryl hydrocarbon receptor interacting protein) is located on chromosome 11q13.2 and encodes a 330 amino acid protein which interacts with the aryl hydrocarbon receptor (AHR) transcription factor. Mutations in the AIP gene have been associated with familial isolated pituitary adenomas (FIPA). They characterize by an early-onset (around the age of 20 years old) and for being aggressive, growth hormone and/or prolactin-secreting tumors, with poor response to somatostatin analogues.

Differential Expression of Stem Cell Markers in Human Adamantinomatous Craniopharyngioma and Pituitary Adenoma

Background/Aims: Although craniopharyngioma (CP) is histologically benign, it is a pituitary tumour that grows rapidly and often recurs. Adamantinomatous CP (ACP) was associated with an activating mutation in ß-catenin, and it has been postulated that pituitary stem cells might play a role in oncogenesis in human ACP. Stem cells have also been identified in pituitary adenoma. Our aim was to characterize the expression pattern of ABCG2, CD44, DLL4, NANOG, NOTCH2, POU5F1/OCT4, SOX2, and SOX9 stem cell markers in human ACP and pituitary adenoma. Methods and Results: We studied 33 patients (9 ACP and 24 adenoma) using real-time quantitative PCR (RT-qPCR) and immunohistochemistry. SOX9 was up-regulated in ACP, exhibiting positive immunostaining in the epithelium and stroma, with the highest expression in patients with recurrence. CD44 was overexpressed in ACP as confirmed by immunohistochemistry. SOX2 did not significantly differ among the tumour types. The RT-qPCR array showed an increased expression of MKI67,OCT4/POU5F1, and DLL4 in all tumours. NANOG was decreased in ACP. ABCG2 was down-regulated in most of the tumours. NOTCH2 was significantly decreased in the adenomas. Conclusion: Our results confirm the presence of stem cell markers in human pituitary tumours as well as the different expression patterns of ACP and adenoma. These findings suggest that ACP may originate from a more undifferentiated cell cluster. Additionally, SOX9 immunodetection in the stroma and the highest expression levels related to the relapse of patients suggest a contribution to the aggressive behaviour and high recurrence of this tumour type.

Gasto energético, composición corporal, trastornos metabólicos e ingesta energética en pacientes con antecedentes de craneofaringioma / Energy expenditure, body composition, metabolic disorders, and energy intake in patients with a history of craniopharyngioma

Introducción: Los craneofaringiomas son malformaciones histológicamente benignas que se sitúan entre el hipotálamo y la hipófisis, zonas con un rol determinante en la modulación de la saciedad. Aun siendo tumores benignos, presentan una considerable morbilidad. La obesidad está presente hasta en un 52% de los pacientes. Objetivo: evaluar factores de riesgo cardiovascular, composición corporal y gasto energético en pacientes con craneofaringioma, y compararlos con un grupo de obesos multifactoriales. Material y métodos: Se incluyeron todos los pacientes con resección quirúrgica de craneofaringioma, menores de 21 años, en seguimiento en nuestro centro entre mayo 2012 hasta abril 2013 que aceptaron participar por medio del consentimiento informado. Se realizó valoración antropométrica, composición corporal con impedanciometría, gasto energético con calorimetría indirecta y valoración de ingesta energética y de macronutrientes. Se determinó resistencia a la insulina (HOMA-IR) y dislipemia. Se comparó a los pacientes con craneofaringioma con obesidad, con un grupo de pacientes con obesidad multifactorial. Resultados: se estudiaron 39 pacientes. El 59% era obeso y presentó significativamente menor% de masa magra (62.4 vs 67.5 p=0.01) y mayor% de masa grasa (37.5 vs 32.5 p=0.01) comparados con los obesos multifactoriales. No se encontró diferencias en el compromiso metabólico entre los obesos con y sin antecedente de craneofaringioma. Se dividieron los pacientes en tertilos según% de gasto energético para categorizar en gasto bajo vs normal. Se encontró asociación positiva entre% de gasto energético y% de masa magra en obesos multifactoriales (68±1%; en los gasto normal vs 62.6± 1% en los gasto bajo: p 0,04). Sin diferencias dentro de la población de obesos con antecedente de craneofaringioma (62±2.7 en los gasto normal/alto vs 61.2±1.8% en los gasto bajo: p 0,8). El gasto energético basal (REE) fue menor en los pacientes con antecedente de craneofaringioma vs obesos multifactoriales, independientemente de la masa magra, lo que sustenta que existirían otros factores que actuarían disminuyendo el gasto energético. No hubo diferencia con respecto a la ingesta en ambos grupos estudiados. Conclusiones: los pacientes con antecedente de craneofaringioma presentan menor gasto energético no relacionado a la masa magra y similar ingesta energética comparado con obesos multifactoriales. No hubo diferencias en el compromiso metabólico entre los obesos con y sin antecedentes de craneofaringioma (AU)

Introduction: Craniopharyngiomas are histologically benign malformations located between hypothalamus and the pituitary gland, areas that play an important role in satiety modulation. Although the tumors are benign, they may cause significant morbidity. Obesity is found in up to 52% of patients. Aim: To assess cardiovascular risk factors, body composition, and energy expenditure in patients with craniopharyngioma, and to compare them to results in a group of children with multifactorial obesity. Material and methods: All patients who underwent surgical resection of craniopharyngioma, younger than 21 years of age, who were being followed-up at our center between May 2012 and April 2013 who gave their informed consent to participate were enrolled in the study. Anthropometric measurements, body composition with impedanciometer, energy expenditure with indirect calorimetry, and energy and macronutrient intake were evaluated. Insulin resistance (HOMA-IR) and dyslipidemia were determined. Patients with craniopharyngioma associated with obesity were compared to patients with multifactorial obesity. Results: Of 39 patients studied, 59% were obese and a significantly lower percentage of lean mass (62.4 vs 67.5 p=0.01) and a higher percentage of fat mass (37.5 vs 32.5 p=0.01) compared to multifactorial obese subjects. No differences were found in metabolic involvement between obese subjects with and those without a history of craniopharyngioma. Patients were divided into tertiles according to percentage of energy expenditure to categorize low versus normal expenditure. A positive correlation was found between percentage of energy expenditure and lean mass percentage in subjects with multifactorial obesity (68±1%; in those with normal energy expenditure versus 62.6±1% in those with low energy expenditure: p 0.04). No difference was found within the group of obese patients with a history of craniopharyngioma (62±2.7 in those with normal/high expenditure versus 61.2±1.8% in those with low expenditure: p 0.8). Baseline energy expenditure (BEE) was lower in craniopharyngioma patients than in those with multifactorial obesity, regardless of lean mass percentage, supporting the hypothesis that other factors may be involved in the decrease of energy expenditure. There was no difference in the food intake between both groups. Conclusions: Patients with a history of craniopharyngioma had a lower energy expenditure unrelated to lean mass and a similar energy intake compared to subjects with multifactorial obesity. No differences were found in metabolic involvement between obese subject with and those without a history of craniopharyngioma (AU)

Resistance to octreotide LAR in acromegalic patients with high SSTR2 expression: analysis of AIP expression / Resistência ao octreotide LAR em pacientes acromegálicos com alta expressão do SSTR2: avaliação da expressão do AIP

We present here the clinical and molecular data of two patients with acromegaly treated with octreotide LAR after non-curative surgery, and who presented different responses to therapy. Somatostatin receptor type 2 and 5 (SSTR2 and SSTR5), and aryl hydrocarbon receptor-interacting protein (AIP) expression levels were analyzed by qPCR. In both cases, high SSTR2 and low SSTR5 expression levels were detected; however, only one of the patients achieved disease control after octreotide LAR therapy. When we analyzed AIP expression levels of both cases, the patient whose disease was controlled after therapy exhibited AIP expression levels that were two times higher than the patient whose disease was still active. These two cases illustrate that, although the currently available somatostatin analogs bind preferentially to SSTR2, some patients are not responsive to therapy despite high expression of this receptor. This difference could be explained by differences in post-receptor signaling pathways, including the recently described involvement of AIP. Arq Bras Endocrinol Metab. 2012;56(8):501-6.

Apresentamos os dados clínicos e moleculares de dois pacientes com acromegalia tratados com octreotide LAR após cirurgia não curativa, com diferentes respostas a essa terapia medicamentosa. As expressões do receptor de somatostatina tipo 2 e 5 (SSTR2 e SSTR5) e da proteína de interação com o receptor aril hidrocarbono (AIP) foram analisadas por qPCR. Em ambos os casos, foi encontrada uma expressão elevada de SSTR2 e baixa do SSTR5. No entanto, o controle da doença foi obtido após tratamento com octreotide LAR em apenas um dos pacientes. Quando analisamos a expressão do AIP em ambos os casos, o paciente cuja doença foi controlada após a terapia medicamentosa apresentou uma expressão duas vezes maior do que a do paciente não controlado com o tratamento. Conclui-se que esses dois casos ilustram que, embora os análogos de somatostatina atualmente disponíveis se liguem preferencialmente ao SSTR2, alguns pacientes não respondem ao tratamento, apesar de uma elevada expressão desse receptor. Isso poderia ser explicado por alterações nas vias de sinalização pós-receptor, incluindo o envolvimento recentemente descrito da AIP. Arq Bras Endocrinol Metab. 2012;56(8):501-6.

Extracellular superoxide dismutase, a potential extracellular biomarker candidate for prolactinoma / Superóxido dismutasa extracelular - candidato potencial a biomarcador extracelular del prolactinoma

AIM: To investigate whether the extracellular superoxide dismutase (EC-SOD) and manganese super-oxide dismutase (Mn-SOD) level changes during prolactinoma (PRL) development. METHODS: Surgical tissues from 37 female patients with PRL were tested for Mn-SOD and serum samples from such PRL patients were tested for EC-SOD level changes with Western Blot. The Mn-SOD level from blood cells was also investigated to show whether the Mn-SOD variation could locate tumorigenesis tissues. RESULTS: According to the patients' age analysis, age 20-40 years is high risk for getting PRL. There is a positive relationship between the PRL severity and EC-SOD. The Mn-SOD level from surgical tissues, but not blood cells, also shows a corresponding positive relationship to PRL severity, which indicates that elevated Mn-SOD might only happen in PRL tumorigenesis tissues. CONCLUSIONS: Extracellular superoxide dismutase is an extracellular protein and the serum EC-SOD could be a good candidate for the diagnoses of prolactinoma.

OBJETIVO: Investigar los cambios de niveles del superóxido dismutasa extracelular (EC-SOD) y el superóxido dismutasa de manganeso (Mn-SOD) durante el desarrollo del prolactinoma (PRL). MÉTODOS: Los tejidos quirúrgicos de 37 pacientes hembras con PRL fueron examinados para investigar los niveles de cambio de Mn-SOD, mediante la técnica de Western Blot. El nivel de Mn-SOD de las células sanguíneas fue investigado para ver si la variación de Mn-SOD puede indicar la localización de tejidos de tumorigénesis. RESULTADOS: Según el análisis de la edad de los pacientes, la edad de 20-40 años presenta un alto riesgo de desarrollar PRL. Hay una relación positiva entre la severidad del PRL y el EC-SOD. El nivel de Mn-SOD en los tejidos quirúrgicos - a diferencia de lo que ocurre en las células sanguíneas - muestra una relación positiva con respecto a la severidad del PRL, lo cual indica que un Mn-SOD elevado, sólo podría tener lugar en los tejidos de la tumorigénesis del PRL. CONCLUSIONES: El superóxido dismutasa extracelular (EC-SOD) es una proteína extracelular, y el EC-SOD sérico podría ser un buen candidato para diagnosticar el prolactinoma.

Variable clinical expression in patients with a germline MEN1 disease gene mutation: clues to a genotype-phenotype correlation

Multiple endocrine neoplasia type 1 is an inherited endocrine tumor syndrome, predominantly characterized by tumors of the parathyroid glands, gastroenteropancreatic tumors, pituitary adenomas, adrenal adenomas, and neuroendocrine tumors of the thymus, lungs or stomach. Multiple endocrine neoplasia type 1 is caused by germline mutations of the multiple endocrine neoplasia type 1 tumor suppressor gene. The initial germline mutation, loss of the wild-type allele, and modifying genetic and possibly epigenetic and environmental events eventually result in multiple endocrine neoplasia type 1 tumors. Our understanding of the function of the multiple endocrine neoplasia type 1 gene product, menin, has increased significantly over the years. However, to date, no clear genotype-phenotype correlation has been established. In this review we discuss reports on exceptional clinical presentations of multiple endocrine neoplasia type 1, which may provide more insight into the pathogenesis of this disorder and offer clues for a possible genotype-phenotype correlation.

Avaliação do perfil e resposta ao tratamento de pacientes portadores de adenoma hipofisário submetidos a radioterapia / Clinical profile and response to treatment of patients with pituitary

OBJETIVO: Avaliar o perfil de pacientes portadores de adenoma hipofisário e a resposta à radioterapia externa. MATERIAL E MÉTODO: Foi realizado estudo retrospectivo com 22 pacientes portadores de adenoma hipofisário, os quais foram submetidos à radioterapia entre março de 2004 e dezembrode 2008. Foram analisadas características dos pacientes, como sexo, idade e quadro clínico, tipo de cirurgia, perfil imuno-histoquímico, dose de radioterapia, resposta à terapia com dosagens hormonais e exames de imagem. RESULTADOS: Observou-se idade mediana de 51 anos, com distribuição semelhante em ambos os sexos. De acordo com a classificação de Hardy para tumores hipofisários, 27,5% apresentavam grau II, 27,5% eram grau III e 45%, grau IV. O principal sintoma apresentado pelos pacientes na ocasião do diagnóstico foi deficiência visual em 77% dos casos, seguido de cefaleia em 68%, acromegalia em 27%, amenorreia em 18% e galactorreia em 4,5%. A abordagem cirúrgica por via transesfenoidal ocorreu em 21 pacientes e em somente um por viatranscraniana, sendo realizadas ressecções parciais em 91% dos casos. Quanto à imuno-histoquímica, a expressão de ACTH foi a mais frequente, estando presente em 41% dos casos. Os pacientes foram tratados em aparelhos de megavoltagem, em sua grande maioria com acelerador linear de 6 MV, com dose total de 45 Gy em 68% e dose de 50,4 Gy em 13% dos casos. O planejamento tridimensional foi utilizado em 20 pacientes. O seguimento mediano foi de 41 meses, sendo observado, no seguimento laboratorial e de imagem, melhora em 73% dos pacientes, estabilidade do quadro em 22,5% e piora em 4,5%. CONCLUSÃO: Os resultados encontrados mostram bons índices de resposta e controle dos tumores de hipófise após radioterapia adjuvante à cirurgia, e por ser uma doença de resposta lenta ao tratamento é grande a probabilidade de melhora ainda maior dos resultados a médio prazo.

OBJECTIVE: To evaluate the clinical profile of patients with pituitaryadenoma and their response to radiotherapy. MATERIAL AND METHOD: Retrospective study with 22 patients with diagnosis of pituitary adenoma which were submitted to radiotherapy between March 2004 and December 2008. Patients' characteristics such as gender, age, clinical presentation, surgical approach, immunohistochemistry profile, dose of radiation and the response to therapy were analyzed using hormonal dosages and imaging exams. RESULTS: The median age was 51 years and equally distributed in both genders. The tumors were divided according to the Hardy's classification: 27.5% had grade II, 27.5% had grade III and 45% had grade IV. The main symptoms presented by patients at diagnosis were visual impairment in 77% of cases, headache in68%, amenorrhea and acromegaly in 27% and galactorrhea in 4.5%. Transphenoidal surgery was performed in 21 patients and only 1 patient was submitted to transcranial approach; 91% of cases had partial resection. Concerning to immunohistochemistry, the expression of ACTH was the most frequent, being present in 41% of cases.The patients were treated in megavoltage equipment mostly with6 MV linear accelerator. The total radiation dose was 45 Gy in 68%of patients and a dose of 50.4 Gy in 13% of cases. Three-dimensionalplanning was used in 20 patients. The median follow-up was 41 months. Laboratory and imaging improvement were observed in 73% of patients, stability in 22.5%, and worsening in 4.5%. CONCLUSION: The results show good rates of response and control of pituitary adenomas by radiation in the first four years after treatment. Considering it has a slow response to treatment, there is a high chance of improvement in results later during the follow-up. Keywords: Radiotherapy; Pituitary; Adenoma.

Evaluación por inmunohistoquímica de la expresión de hormonas hipofisiarias y del marcador de proliferación celular Ki-67 en tejido de adenomas causantes de acromegalia / Immunohistochemistry for pituitary hormones and Ki-67 in growth hormone producing pituitary adenomas

Background: Growth hormone (GH) producing adenomas, frequently express several hormones. This condition could confer them a higher proliferative capacity. Ki-67 is a nuclear protein antigen that is a marker for proliferative activity. Aim: To measure the immunohistochemical hormone expression in pituitary adenomas, excised from patients with acromegaly. To determine if the pluríhormonal condition of these adenomas is associated with a higher proliferative capacity, assessed through the expression of Ki-67. Material and methods: Forty one paraffin embedded surgical samples of pituitary adenomas from patients with acromegalia were studied. Immunohistochemistry for GH, prolactin (PRL), follicle stimulating hormone (FSH), luteinizing hormone (LH), thyroid stimulating hormone (TSH), adrenocorticotropin (ACTH) and for the expression of Ki-67 was carried out. Results: All samples were positive for GH. Twenty seven had positive staining for PRL, 12 had positive staining for glycoproteic hormones and 11 for PRL and one or more glycoproteic hormones. Mean staining for Ki-67 was Z.6±3.3 percent. There were no differences in the expression of this marker between mono or pluríhormonal tumors. The expression was neither associated with extrasellar extensión. Conclusions: Half of GH producing pituitary adenomas are pluríhormonal. There are no differences in the expression of Ki-67 between mono and plurihormonal adenomas.

Aspectos moleculares da tumorigênese hipofisária: [revisão] / Molecular aspects of pituitary tumorigenesis: [review]

Os tumores hipofisários, adenomas em sua quase totalidade, são de ocorrência freqüente, representando 10 por cento a 15 por cento de todas as neoplasias intracranianas. Estas lesões são classificadas em microadenomas (< 10 mm) ou macroadenomas (> 10 mm) e como secretoras ou quiescentes (não-funcionantes). Estes tumores são capazes de secretar, de maneira autônoma, os hormônios adenohipofisários, como o hormônio de crescimento (GH), a prolactina (PRL), o hormônio adrenocorticotrófico (ACTH), o hormônio tireotrófico (TSH), o hormônio folículo estimulante (FSH) e o hormônio luteinizante (LH). A ocorrência de metástase, caracterizando um carcinoma hipofisário, é bastante rara, mas são relativamente comuns tumores de comportamento agressivo que exibem sinais de invasão local. Embora a sua patogênese ainda não seja plenamente caracterizada, muitos mecanismos moleculares envolvidos na tumorigênese hipofisária já foram desvendados. Nesta revisão, serão descritos avanços consideráveis realizados na última década relativos à compreensão dos fatores envolvidos na progressão tumoral, incluindo a participação de oncogenes, supressores tumorais e fatores de crescimento.

Pituitary tumors, almost invariably adenomas, are of frequent occurrence, accounting for 10 percent to 15 percent of all the intracranial neoplasm. They are classified as microadenomas (< 10 mm) or macroadenomas (> 10 mm) and as secreting or clinically non-secreting (or not functioning) adenomas. These tumors are autonomously capable to release pituitary hormones such as the growth hormone (GH), prolactin (PRL), adrenocorticotropic hormone (ACTH), thyroid stimulating hormone (TSH), follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The occurrence of metastases, characterizing a pituitary carcinoma, is exceedingly rare. However tumors with aggressive behavior, leading to local invasion, are relatively common. Although the pathogenesis of pituitary tumors is fully characterized, many molecular mechanisms of pituitary tumorigenesis had already been revealed. This review intents to describe advances in the understanding of the involved advances that have been made in the last decade concerning pituitary tumors progression, including the participation of oncogenes, tumor suppressor genes and growth factors.

Expression of p53, Ki-67 and c-erb B2 in growth hormone-and/or prolactin-secreting pituitary adenomas

Os eventos subcelulares implicados na formação e comportamento dos adenomas hipofisários não são completamente compreendidos. Neste estudo nós investigamos a presença de p53, Ki-67 e c-erb B2 em 38 adenomas hipofisários com positividade imuno-histoquímica para GH e prolactina (n=26, 68,4%), para prolactina (n=9, 23,7%) e para GH (n=3, 7,8%). A análise revelou os seguintes resultados: 24 tumores (63,2%) expressaram positividade variável para c-erb B2, 11 (28,9%) expressaram positividade para p53 e 11 tumores (28,9%) foram variavelmente positivos para Ki-67. Nossos resultados demonstraram elevada percentagem de tumores secretores de GH/prolactina, prolactina e GH com positividade imuno-histoquímica para c-erb B2. Desde que este receptor de membrana está relacionado aos fatores de crescimento EGF e TGFa e ambos têm efeito definido no crescimento tumoral, nossos dados sugerem possível função para o c-erb B2 na evolução destes tumores.

Caracterização clínica e imunoistoquímica dos adenomas clinicamente não-funcionantes de hipófise / Non-functioning pituitary adenomas: clinical features and immunohistochemistry

Adenomas clinicamente não-funcionantes de hipófise, não produzem clínica de hipersecreção hormonal. Por esse motivo, seus sinais e sintomas dependem de seu efeito de massa no sistema nervoso central. A sua etiopatogenia é complexa com vários fatores provavelmente influenciando seu desenvolvimento como os hormônios hipotalâmicos (GHRH), fatores de crescimento (FGF), fatores de proliferação (PCNA, e KI-67), proteína P53 e proto-oncogene c-erb-B2. OBJETIVOS: 1) Determinar as características clínicas da população de 117 pacientes tratados com adenoma clinicamente não-funcionante de hipófise (idade, sexo, tamanho do tumor, número de procedimento cirúrgico, desenvolvimento de deficiência hormonal e hiperprolactinemia). 2) Identificar, após a caracterização clínica desses pacientes, aqueles com adenoma clinicamente não-funcionante que apresentam imunoistoquímica positiva para os hormônios hipofisários PRL LH, FSH, GH, TSH e ACTH. 3) Precisar nessa população a positividade imunoistoquímica para o fator de proliferação celular Ki-67, para a proteína P53 e para a proteína C-erb-B2 correlacionando a sua positividade com o tamanho e invasão tumoral. Dessa forma avaliando o valor prognóstico desses fatores de proliferação. 4) Confrontar os resultados da imunoistoquímica realizada através do bloco padrão com os resultados da imunoistoquímica obtidos através do tissue micro-array. MÉTODO: Estudo das características clínicas de 117 pacientes com adenoma clinicamente não-funcionate de hipófise (idade, sexo, tamanho do tumor, número de procedimento cirúrgico, desenvolvimento de deficiência hormonal e hiperprolactinemia). Estudo imunoistoquímico (H&E) de 39 pacientes para hormônios hipofisários, para a proteína P53, proteína C-erb-B2, Ki-67 e sua correlação com crescimento tumoral. A seguir, também foi realizado o tissue micro-array dos 39 casos, estudados anteriormente, com imunoistoquímica para os hormônios hipofisários, para a proteína P 53, proteína C-erb-B2, Ki-67 e sua correlação com o crescimento tumoral. RESULTADOS: Não houve diferença estatisticamente significante entre os sexos masculino e feminino com relação à idade, tamanho tumoral e número de procedimentos cirúrgicos (p=0,279, p=0,813, p=0,139 respectivamente)...

Regulation of pituitary hormones and cell proliferation by components of the extracellular matrix

The extracellular matrix is a three-dimensional network of proteins, glycosaminoglycans and other macromolecules. It has a structural support function as well as a role in cell adhesion, migration, proliferation, differentiation, and survival. The extracellular matrix conveys signals through membrane receptors called integrins and plays an important role in pituitary physiology and tumorigenesis. There is a differential expression of extracellular matrix components and integrins during the pituitary development in the embryo and during tumorigenesis in the adult. Different extracellular matrix components regulate adrenocorticotropin at the level of the proopiomelanocortin gene transcription. The extracellular matrix also controls the proliferation of adrenocorticotropin-secreting tumor cells. On the other hand, laminin regulates the production of prolactin. Laminin has a dynamic pattern of expression during prolactinoma development with lower levels in the early pituitary hyperplasia and a strong reduction in fully grown prolactinomas. Therefore, the expression of extracellular matrix components plays a role in pituitary tumorigenesis. On the other hand, the remodeling of the extracellular matrix affects pituitary cell proliferation. Matrix metalloproteinase activity is very high in all types of human pituitary adenomas. Matrix metalloproteinase secreted by pituitary cells can release growth factors from the extracellular matrix that, in turn, control pituitary cell proliferation and hormone secretion. In summary, the differential expression of extracellular matrix components, integrins and matrix metalloproteinase contributes to the control of pituitary hormone production and cell proliferation during tumorigenesis.

Clinical Significance of Ki-67 Labeling Index in Pituitary Macroadenoma

The aim of our study was to investigate the correlation of the proliferative activity of pituitary neoplasms with clinical characteristics and recurrences. Tumor specimens were obtained from 44 consecutive patients with pituitary macroadenomas who underwent surgery between July 1998 and August 2003. Specimens were immediately fixed in 10% buffered formalin and then embedded in paraffin. The Ki-67 antigen was assessed by immumohistochemical analysis using the monoclonal antibody. We investigated the correlation of the Ki-67 labeling index with the following clinical and radiological characteristics: sex, age, presence or absence visual field defect, tumor classification, maximal tumor diameter, Hardy's classification, type of tumor, invasiveness, and recurrence. Our study suggests that the clinical characteristics such as visual field defect and recurrence are correlated with the high Ki-67 labeling index. No statistical differences were observed in the Ki-67 labeling index in relation to the following characteristics: sex, age, tumor classification, maximal tumor diameter, Hardy's classification, type of tumor, and invasiveness into the sphenoid sinus or cavernous sinus.

Adenomas hipofisários: relaçäo entre invasividade e índice proliferativo tumoral / Pituitary adenomas: relationship between invasiveness and proliferative cell nuclear index

Analisamos 76 pacientes com adenomas hipofisários do ponto de vista clínico, radiológico e tratamento cirúrgico. Todos os casos foram estudados por imuno-histoquímica e em 49 pacientes foi pesquisado o anticorpo monoclonal PCNA. Os adenomas bi-hormonais foram os mais frequentes seguidos dos prolactinomas e os adenomas näo secretantes. Os adenomas bi-hormonais näo secretantes e os produtores de subunidade alfa foram proporcionalmente mais invasivos pelos critérios radiológicos. A maioria dos pacientes (59) foi operada por via transeptoesfenoidal, em seis casos a via transcraniana foi realizada e em 11 pacientes houve necessidade das duas abordagens. A ressecçäo foi total em 32 pacientes, a maioria em microadenomas, subtotal em 15 e parcial em 29. A complicaçäo endócrina mais frequente foi diabetes insipidus. Houve tendência de associaçäo positiva para os adenomas secretantes e PCNA mais elevado, assim como relaçäo positiva quando analisamos os adenomas invasivos pela tomografia computadorizada ou ressonância magnética e o PCNA 3 e 4. A melhora visual foi observada em 85 por cento dos macroadenomas, mesmo quando a ressecçäo foi parcial ou subtotal

Avaliaçäo da atividade secretora, proliferaçäo celular e expressäo da proteína p27 em tumores hipofisários / Evaluation of secretory activity, cell proliferation and expression of p27 protein in hypophyseal tumors

A finalidade deste estudo foi avaliar a atividade secretora, proliferaçäo celular e inibiçäo do ciclo celular das neoplasias hipofisárias. Os tecidos foram obtidos de 13 pacientes incluindo acromegalia (n=5), adenomas näo-secretores (n=4), hiperprolactinemia (n=3) e doença de Cushing (n=1). Os espécimes foram examinados por técnica imuno-histoquímicacom anticorpos anti-ACTH, anti-TSH, anti-LH, anti-FSH, anti-PRL, anti-hGH, anti MIB-1 (análise da proliferaçäo celular)e anti-p27(análise da inibiçäo do ciclo celular). A expressäo imunohistoquímica quanto à atividade secretora nos tumores hipofisários demonstrou que todos produziam mais que um hormôni. As células positivas para o marcador de proliferaçäo celular MIB-1 mostraram-se presentes em aproximadamente 46 por cento dos casos. A maior taxa proliferativa foi encontrada nos tumores com com quadro clínico de acromegalia (80 por cento dos casos). A taxa d positividade para a proteína p27 foi de aproximadamente 38 por cento, sendo, em média, maior no tumor responsável pela doença de Cushing. Esses resultados demonstram que os adenomas multisecretores säo relativamente comuns. Os índices de proliferaçäo celular baixos e os nveis de p27 próximos àqueles observados em tecidos normais expressam o baixo nível de proliferaçäo celulas destes tumores.

Usefulness of insulin-like growth factor binding protein-3 levels to determine acromegaly activity and effectiveness of transsphenoidal pituitary surgery

Background. Several series reported in the literature concerning the results of the treatment of acromegaly have difficult to evaluated because the indicators are inaccurate Methods. We investigated the usefulness of insulin. Like growth factor binding protein-3 (IGFBP) levels to determine disease activity after surgical treatment of acromegaly in 13 patients with confirmed somatotroph adenoma. Results. Before surgery, all 13 non-treated patients had levated serum levels of IGFBP-3 as well as total and free IGF-I. In addition, there was no overlap with the normal controls (p < 0.001). IGFBP-3 levels correlated significantly (0.91, p < 0.001) with GH suppressibility by glucose after surgery. Conclusions. These data confirm that IGFBP-3 is a better indicator of acromegalic activity than either total or free IGF-i. There was a high correlation with GH suppressibility by glucose after surgery; both free and total IGF-I could be considered sensitive markers only for diagnosis of active acromegaly but not for efficacy of surgery

Growth hormone-producing pituitary tumours: clinical profile and results of surgery.

BACKGROUND: Growth hormone-producing pituitary tumours present with a wide variety of manifestations. The optimum diagnostic work up, management and follow up of such patients is complex and involves a multidisciplinary approach. There is paucity of data from India with regard to the clinical presentation and results of surgery for growth hormone-producing tumours. METHODS: We studied the first 50 patients presenting during 1989-94 with growth hormone-producing pituitary tumours to our centre. The work up included detailed endocrine and radiological assessment. The surgical outcome was analysed for 35 patients who were operated (trans-sphenoidal 29, transcranial 6) at our centre. RESULTS: All the patients had macroadenomas [mean (SD) diameter 3.12 (0.87) cm]. Seventy-five per cent of the patients had supra- and/or parasellar extension and 57% had visual field defects. Tumour size correlated with the preoperative basal (r = 0.57) and glucose-suppressed (r = 0.54) growth hormone levels. Thirty-three of the 35 patients operated at our centre (trans-sphenoidal 28, transcranial 5) were available for follow up (median duration 34 months). After trans-sphenoidal surgery alone, 12 of the 28 (43%) patients had normalization of growth hormone levels (post-glucose growth hormone < 5 ng/ml), and 9 of 11 (82%) showed improvement in visual fields. CONCLUSION: In India, growth hormone-producing pituitary tumours are usually large in size. The growth hormone levels correlate with the size of the tumour. These tumours can be effectively treated by trans-sphenoidal or transcranial surgery.

Gamma knife surgery in pituitary microadenomas

The application of transsphenoidal microsurgery in the management of pituitary microadenoma, long regarded as effective surgical treatment, has had a relatively low mortality and morbidity rate. However early failure and late recurrence has been reported in no small numbers. It has been proposed that stereotactic radiosurgery is an alternative treatment modality. Recent advances in neuroimaging permits precise targeting in radiosurgery of microadenomas. Additionally, a prompt hormonal reduction after the treatment is important for the patients with hormonally active microadenomas. The authors performed Gamma Knife radiosurgery in 27 patients with pituitary adenomas and observed the hormonal changes after radiosurgery in 19 patients with functioning microadenomas (5 with Cushing's disease, 7 with acromegaly, and 7 with prolactinoma). The maximum dose administered ranged from 25 to 75 Gy. The margin of the tumor was encompassed within the 50 to 90% isodose volume. The endocrinological status was assessed pre- and post-operatively. We measured the serum growth hormone and prolactin level, as well as the 24-hour urinary free-cortisol level. Normalization of the hormonal level was achieved in 6 cases, the majority of them within 10 months. The other 6 cases showed marked reduction of hormonal levels (less than 50% of preoperative levels) with a strong possibility of hormonal remission at further follow-up. The remaining 6 were failures. The cure for one case is still pending. It took approximately 1 approximately 3 months after the radiosurgery before the reduction of hormonal secretion began to show up with some improvement of symptoms. When the GKS was successful, hormonal secretion seemed to return to normal within 10 months. Although further follow-up is necessary to evaluate the long-term tumor control rate and hormonal effect, these initial results indicate a potential therapeutic role of radiosurgery in controlling hormone hypersecretion in pituitary microadenomas. Gamma knife radiosurgery is very promising in managing pituitary microadenoma with complementary of the transsphenoidal surgery.

Caracterización hormonal de los adenomas hipofisarios no funcionantes / Hormonal characterization of the non fuctioning pituitary adenomas

Se estudiaron 98 pacientes con adenomas no funcionantes, 34 hombres y 64 mujeres, realizando un estudio hormonal en suero para conocer su perfil endocrino. Con tal objeto, se efectuaron determinaciones de hormona folículo estimulante y hormona luteinizante (FSH, LH), prolactina (PRL), estadiol (E2), testosterona (T), cortisol, hormona del crecimiento (GH), hormona adrenocorticotrópica (ACTH), hormona estimulante del tiroides (TSH) y gastrina (Ga) por radioinmunoanálisis. Los resultados mostraron marcado hipergonadotropismo en el 47//de los pacientes, con niveles séricos de FSH y LH muy elevados y un incremento inesperado de la concentración de Ga (Grupo I). En contraste, el resto de los pacientes tuvo concentraciones normales o bajas de gonadotrofinas y Ga (Grupo II). El grupo I mostró una relación inversa entre los niveles de gonadotropinas y esteroides gonadales (E2 o T) con cifras significativamente menores que los valores normales y los encontrados en el Grupo II (<0,00l) en el cual la relación fue lineal positiva. Tambien se observó una relación directa entre la concentración de FSH conTSH (r=0,75) y Ga (r=0,80), probablemente por los neurotransmisores que determinan la secreción de estas hormonas. La TSH al igual que las hormonas tiroideas, tuvo cifras más elevadas en el Grupo I, mientras que los valores de PRL fueron más bajos (P<0,0001). La concentración de GH y ACTH fuer normal en ambos,no obstante,el 33 por ciento de los pacientes del Grupo II presentó hipocortisolismo e hipotiroidismo. La edad promedio de los pacientes analizada por décadas, no fue estadísticmente diferente entre los grupos y no explica las diferencias encontradas, aunque en el Grupo I predominaron las mujeres. En éstas, la elevación de FSH podría estar condicionada por la deficiencia gonadal, acorde a la edad de las pacientes (49,8 Ð 9,6 años), sin embargo, algunos valores fueron extraordinariamente elevados y existe la posibilidad de que la hipófisis en condiciones patológicas, como es la forma adenomatosa,pueda producir en forma autónoma,moléculas de LH y FSH alteradas y carentes de actividad biológica, o bien, subunidad Ó libre, como se ha demostrado en algunos gonadotropomas. Por otra parte, algunos de los casos con TSH elevada podrían considerarse verdaderos TS-Homas, que no suprimen su secreción a pesar de la elevada concentración de hormonas tiroideas. Así, podría decirse que dentro de los no funcionantes, están enmarcados algunos de estos adenomas. Se concluye que, desde el punto de vista hormonal, los adenomas del Grupo II son los verdaderos no funcionantes

A clinico-pathologic study of pituitary adenomas.

One hundred patients of pituitary adenoma were studied using light microscopy, electron microscopy, immunohistochemistry and serum hormone estimation. Depending on the absence or presence of clinical endocrine manifestation they were divided into 2 groups 'non-functioning' (group I -48 patients) and 'hyper-functioning' (group II- 52 patients). Tumours in group I were chromophobes, some of which (group IA) had no hormone increase in serum nor detection in tissues and ultrastructurally they consisted of secretorily inactive cells (null cell adenomas) while others (group IB) were composed of secretorily active cells with prolactin consistently increased in serum and localized in tissue (lactotroph adenomas). Tumours in group II were chromophobe, acidophil, basophil or mixed adenomas with varying number of secretorily active cells in all. The hormone responsible for the hyperfunction was always raised in serum and localized in tissue. Thus growth hormone was demonstrated in all tumours from patients with acromegaly (somatotroph adenomas), prolactin in all tumours from patients with galactorrhea (lactotroph adenomas) and ACTH in all tumours from patients with Cushing's syndrome (corticotroph adenomas). It was observed, however, that 40 per cent of tumours were pleurihormonal, growth hormone and prolactin being the commonest combination. Interestingly, not all the hormones localized by immunohistochemistry in pleurihormonal adenomas were detected in serum and/or reflected in the clinical picture.