Glucose-dependent insulinotropic peptide receptor overexpression in adrenocortical hyperplasia in MEN1 syndrome without loss of heterozygosity at the 11q13 locus

BACKGROUND: The molecular mechanisms involved in the genesis of the adrenocortical lesions seen in MEN1 syndrome (ACL-MEN1) remain poorly understood; loss of heterozygosity at 11q13 and somatic mutations of MEN1 are not usually found in these lesions. Thus, additional genes must be involved in MEN1 adrenocortical disorders. Overexpression of the glucose-dependent insulinotropic peptide receptor has been shown to promote adrenocortical tumorigenesis in a mice model and has also been associated with ACTH-independent Cushing syndrome in humans. However, to our knowledge, the status of glucose-dependent insulinotropic peptide receptor expression in adrenocortical lesions in MEN1 has not been previously investigated. OBJECTIVE: To evaluate glucose-dependent insulinotropic peptide receptor expression in adrenocortical hyperplasia associated with MEN1 syndrome. MATERIALS/METHODS: Three adrenocortical tissue samples were obtained from patients with previously known MEN1 germline mutations and in whom the presence of a second molecular event (a new MEN1 somatic mutation or an 11q13 loss of heterozygosity) had been excluded. The expression of the glucose-dependent insulinotropic peptide receptor was quantified by qPCR using the DDCT method, and b-actin was used as an endogenous control. RESULTS: The median of glucose-dependent insulinotropic peptide receptor expression in the adrenocortical lesions associated with MEN1 syndrome was 2.6-fold (range 1.2 to 4.8) higher than the normal adrenal controls (p = 0.02). CONCLUSION: The current study represents the first investigation of glucose-dependent insulinotropic peptide receptor expression in adrenocortical lesions without 11q13 loss of heterozygosity in MEN1 syndrome patients. Although we studied a limited number of cases of MEN1 adrenocortical lesions retrospectively, our preliminary data suggest an involvement of glucose-dependent insulinotropic peptide receptor overexpression in the etiology of adrenocortical hyperplasia. New prospective studies will be able to clarify the exact role of the glucose-dependent insulinotropic peptide receptor in the molecular pathogenesis of MEN1 adrenocortical lesions.

Analysis of glucose-dependent insulinotropic peptide receptor (GIPR) and luteinizing hormone receptor (LHCGR) expression in human adrenocortical hyperplasia / Análise da expressão dos receptores do peptídeo insulinotrópico dependente de glicose (GIPR) e do hormônio luteinizante (LHCGR) nas hiperplasias adrenocorticais humanas

OBJECTIVE: To analyze the aberrant expression of the GIPR and LHCGR in different forms of adrenocortical hyperplasia: ACTH-independent macronodular adrenal hyperplasia (AIMAH), primary pigmented nodular adrenocortical disease (PPNAD) and diffuse adrenal hyperplasia secondary to Cushing's disease (DAHCD). METHODS: We quantified GIPR and LHCGR expressions using real time PCR in 20 patients with adrenocortical hyperplasia (seven with AIMAH, five with PPNAD, and eight with DAHCD). Normal adrenals tissues were used as control and the relative expression was compared with β-actin. RESULTS: GIPR and LHCGR expressions were demonstrated in all tissues studied. Median GIPR and LHCGR mRNA levels were 1.6; 0.4; 0.5 and 1.3; 0.9; 1.0 in adrenocortical tissues from AIMAH, PPNAD and DAHCD respectively. There were no differences between GIPR and LHCGR expressions in all tissues studied. CONCLUSIONS: GIPR and LHCGR overexpression were not identified in the studied cases, thus suggesting that this molecular mechanism is not involved in adrenocortical hyperplasia in our patients.

OBJETIVO: Analisar a expressão aberrante do GIPR e do LHCGR em diferentes formas de hiperplasias adrenocorticais: hiperplasia adrenal macronodular independente de ACTH (AIMAH), doença adrenocortical nodular pigmentada primária (PPNAD) e hiperplasia adrenal difusa secundária à doença de Cushing (DAHCD). MÉTODOS: Quantificou-se por PCR em tempo real a expressão desses receptores em 20 pacientes: sete com AIMAH, cinco com PPNAD e oito com DAHCD. Adrenais normais foram utilizadas como controle e a expressão relativa desses receptores foi comparada à expressão da β-actina. RESULTADOS: A expressão desses receptores foi demonstrada em todos os tecidos estudados. A mediana da expressão do GIPR e do LHCGR foi de 1,6; 0,4; 0,5 e de 1,3; 0,9; 1,0 nos tecidos dos pacientes com AIMAH, PPNAD e DAHCD, respectivamente. Não houve diferença significativa na expressão desses receptores nos tecidos estudados. CONCLUSÕES: Hiperexpressão do GIPR e do LHCGR não foi observada, sugerindo que esse mecanismo não está envolvido na patogênese molecular da hiperplasia adrenal nesses pacientes.

Absence of PRKAR1A loss of heterozygosity in laser-captured microdissected pigmented nodular adrenocortical tissue from a patient with Carney complex caused by the novel nonsense mutation p. Y21X / Ausência da perda de heterozigose do PRKAR1A em células capturadas por microdissecção a laser de tecido de nódulo pigmentoso adrenocortical de um paciente com complexo de Carney causado por uma nova mutação nonsense

OBJECTIVE: Primary pigmented nodular adrenocortical disease (PPNAD) is the main endocrine manifestation of Carney complex, a multiple neoplasia syndrome caused by PRKAR1A gene mutations. The presence of PRKAR1A loss of heterozygosity (LOH) in adrenocortical tumorigenesis remains controversial. The aim of the present study is to investigate the presence of PRKAR1A LOH in adrenocortical cells in a patient with Carney complex. METHODS: The LOH was investigated using a PRKAR1A informative intragenic marker by GeneScan software analysis in DNA obtained from laser-captured microdissected cells of several adrenal nodules. Patients: A young adult male patient with Carney complex and his family were studied. RESULTS: A novel heterozygous mutation (p. Y21X) was identified at PRKAR1A in blood DNA of the male proband and his relatives. No PRKAR1A LOH was evidenced in the laser-captured microdissected cells from PPNAD tissue by different methodologies. CONCLUSION: We identified a new PRKAR1A nonsense mutation and in addition we did not evidence PRKAR1A LOH in laser-captured nodules cells, suggesting that adrenocortical tumorigenesis in PPNAD may occurs apart from the second hit.

OBJETIVO: A doença adrenocortical nodular pigmentosa primária (PPNAD) é uma das manifestações do complexo de Carney, uma neoplasia endócrina múltipla causada por mutações no PRKAR1A. A perda de heterozigose (LOH) do PRKAR1A na tumorigenese adrenal permanece controversa dada à possibilidade de contaminação com o tecido normal. Nosso objetivo foi investigar a presença de LOH no PRKAR1A a partir de células do nódulo adrenal de um paciente com complexo de Carney. MÉTODOS: A pesquisa da LOH do PRKAR1A foi realizada através do estudo de um marcador intragênico em DNA de células do nódulo adrenal microdissecadas a laser, evitando contaminação com o tecido normal. Pacientes: Um paciente com PPNAD e cinco familiares foram estudados. RESULTADOS: A nova mutação (p. Y21X) foi identificada no PRKAR1A sem evidência de LOH no tecido adrenal. CONCLUSÃO: Identificamos uma nova mutação no PRKAR1A e não evidenciamos LOH nas células dos nódulos adrenocorticais, sugerindo que a PPNAD possa ocorrer na ausência de um segundo evento molecular.

Cushing's syndrome secondary to ACTH-Independent macronodular adrenal hyperplasia

ACTH-Independent macronodular adrenal hyperplasia (AIMAH) is a rare cause of endogenous Cushing's syndrome (CS), in which clinical features usually become apparent only after several decades of life. This form of adrenal hyperplasia typically produces excess cortisol with overt or subclinical CS, but concurrent secretion of mineralocorticoids or sexual steroids can also occur. The diagnosis is suspected by bilateral adrenal nodules larger than 1 cm on incidental imaging studies or following the demonstration of ACTH-independent hormonal hypersecretion. The pathophysiology of this entity is heterogeneous and has been intensely explored in recent years. Several G-protein coupled receptors aberrantly expressed in the adrenal cortex have been implicated in the regulation of steroidogenesis and in the initial cell proliferation in AIMAH. Several familial cases of AIMAH have been recently described with the same pattern of aberrant hormone receptors in all affected members of the family. It is probable that additional somatic genetic events related to cell cycle regulation, adhesion and transcription factors occur in addition over time in the various nodules; other mechanisms, as Gsp or ACTH receptor mutations and paracrine adrenal hormonal secretion have been rarely identified as the molecular mechanism in some cases. When systematically screened, most patients with AIMAH exhibit an in vivo aberrant cortisol response to one or various ligands suggesting the presence of aberrant adrenal receptors. The identification of these receptors creates the possibility of a specific pharmacological treatment isolated or associated with adrenalectomy.

A hiperplasia adrenal macronodular independente de ACTH (AIMAH) é uma causa rara de síndrome de Cushing (SC) endógena, na qual alguns aspectos clínicos só se tornam evidentes depois de várias décadas de vida. Esta forma de hiperplasia adrenal caracteristicamente produz excesso de cortisol resultando na síndrome de Cushing franca ou subclínica, embora a secreção concomitante de mineralocorticóide, estrógeno e andrógenos também possa ocorrer. A suspeita diagnóstica é feita pela presença de nódulos adrenais bilaterais maiores que 1 cm, como achado incidental em exames de imagem ou pela demonstração de hipersecreção hormonal independente de ACTH. A fisiopatologia desta doença é heterogênea e tem sido intensamente estudada nos últimos anos. Vários receptores acoplados à proteína G, com expressão aberrante no córtex adrenal, têm sido implicados na regulação da esteroidogênese e no início da proliferação celular que ocorre na AIMAH. Diversos casos familiais de AIMAH foram recentemente descritos, e um mesmo padrão de expressão anormal dos receptores aberrantes foi observado em todos os membros afetados das famílias investigadas. Ao longo do tempo, é provável que ocorram, nos nódulos, eventos genéticos adicionais relacionados à regulação do ciclo celular, adesão e fatores de transcrição. Outros mecanismos moleculares, como mutações nos genes da proteína Gsa e do receptor de ACTH, ou secreção hormonal parácrina na adrenal, têm sido raramente identificados em alguns casos. A maioria dos pacientes com AIMAH, quando sistematicamente investigados, desenvolve uma produção anormal de cortisol em resposta a vários ligantes, sugerindo a presença de receptores adrenais aberrantes. A identificação destes receptores cria a possibilidade para um tratamento farmacológico específico isolado ou associado à adrenalectomia.

Síndrome de Nelson: relato de caso / Nelson's Syndrome: a case report

O objetivo deste artigo é apresentar e discutir alguns aspectos da patogênese, do diagnóstico clínico, hormonal e radiológico e do tratamento da síndrome de Nelson, com base no relato de um paciente típico portador da doença, no qual várias abordagens terapêuticas mostraram-se ineficazes.

The aim of this article is to present and discuss several aspects of the pathogenesis, the clinical, hormonal, and imaging diagnosis, and the treatment of Nelson's syndrome, based on a typical patient's report, in whom several therapeutic approaches were shown to be ineffective.

Estudo da expressão dos receptores do peptídeo insulinotrópico dependente de glicose (GIPR) e do hormônio luteinizante (LHCGR) em tumores e hiperplasias do córtex adrenal / Expression study of glucose-dependent insulinotropic peptide receptor (GIPR) and luteinizing hormone receptor (LHCGR) in adrenocortical tumors and hyperplasia

O objetivo deste estudo foi quantificar por PCR em tempo real a expressão dos genes dos receptores do peptídeo insulinotrópico dependente de glicose (GIPR) e do hormônio luteinizante (LHCGR) em tumores e hiperplasias adrenocorticais (hiperplasia adrenal macronodular independente de ACTH; doença nodular adrenocortical pigmentosa primária e aumento da adrenal associado à neoplasia endócrina múltipla tipo 1). O nível de expressão do GIPR foi mais elevado nos tumores malignos que nos benignos em pacientes adultos e pediátricos, enquanto o nível de expressão do LHCGR foi extremamente baixo nos tumores malignos em pacientes adultos. Não se observou diferença no nível de expressão de ambos os receptores nas diferentes formas de hiperplasia.

The aim of this study was to quantify by real-time PCR the gene expression of glucose-dependent insulinotropic peptide receptor (GIPR) and luteinizing hormone receptor (LHCGR) in adrenocortical tumors and hyperplasia (ACTH-independent macronodular adrenal hyperplasia, primary pigmented nodular adrenocortical disease and adrenal enlargement associated with multiple endocrine neoplasia type 1. The GIPR expression level was more elevated in the malignant tumors that in the benign ones, of both adult and pediatric patients, whereas the level of LHCGR expression was extremely low in malignant tumors of adult patients. No difference in the expression level of these receptors was observed in the different forms of adrenocortical hyperplasia.