Somatostatin (SST), an inhibitory polypeptide with two biologically active forms SST14 and SST28, inhibits GH, prolactin (PRL), TSH, and ACTH secretion in the anterior pituitary gland. SST also has ...an antiproliferative effect inducing cell cycle arrest and apoptosis. Such actions are mediated through five G-protein-coupled somatostatin receptors (SSTR): SSTR1–SSTR5. In GH-secreting adenomas, SSTR2 expression predominates, and somatostatin receptor ligands (SRLs; octreotide and lanreotide) directed to SSTR2 are presently the mainstays of medical therapy. However, about half of patients show incomplete biochemical remission, but the definition of resistance per se remains controversial. We summarize here the determinants of SRL resistance in acromegaly patients, including clinical, imaging features as well as molecular (mutations, SSTR variants, and polymorphisms), and histopathological (granulation pattern, and proteins and receptor expression) predictors. The role of SSTR5 may explain the partial responsiveness to SRLs in patients with adequate SSTR2 density in the cell membrane. In patients with ACTH-secreting pituitary adenomas, i.e. Cushing's disease (CD), SSTR5 is the most abundant receptor expressed and tumors show low SSTR2 density due to hypercortisolism-induced SSTR2 down-regulation. Clinical studies with pasireotide, a multireceptor-targeted SRL with increased SSTR5 activity, lead to approval of pasireotide for treatment of patients with CD. Other SRL delivery modes (oral octreotide), multireceptor-targeted SRL (somatoprim) or chimeric compounds targeting dopamine D2 receptors and SSTR2 (dopastatin), are briefly discussed.
Interest has been focused on differentiating anatomical, molecular, and physiological characteristics of the types of mammalian adipose tissues. White adipose tissue (WAT) and brown adipose tissue ...(BAT) are the two main forms of adipose tissue in humans. WAT functions as an endocrine organ and serves as a reservoir of energy in the form of triglycerides. The hormones released by WAT are called adipokines. BAT consists of a group of specialized cells with abundant uncoupling protein 1 (UCP1) in the inner mitochondrial membrane and also fulfills endocrine functions. Following the identification of functional (BAT) in human adults, there has been a great deal of interest in finding out how it is induced, its localization, and the mechanisms by which it regulates thermogenesis. Fibroblast growth factor 21 (FGF21) is a key regulator of the differentiation to brown adipocytes. The main mechanisms occur through enhancing UCP1 expression. In addition, following exposure to cold or exercise, FGF21 induces upregulation of local peroxisome proliferator-activated receptor gamma co-activator (PGC)-1-alfa and thus promotes thermogenesis in adipose tissue and skeletal muscle. FGF21 integrates several pathways allowing the regulation of human energy balance, glucose levels, and lipid metabolism. Such mechanisms and their clinical relevance are summarized in this review.
Summary
Objective
To evaluate the quality of life (QoL) in patients with pituitary adenomas in comparison with healthy Mexican population QoL scores.
Design & Measurements
Cross‐sectional study using ...the short form 36 questionnaire (SF‐36) in 175 patients with pituitary adenomas grouped by adenoma subtype and disease activity, and compared them with the healthy Mexican population normative QoL scores.
Patients
A total of 44 patients with non‐functioning pituitary adenomas (NFPA), 48 with acromegaly, 53 with prolactinomas and 30 with Cushing disease (CD) were enrolled in this study.
Results
Mental and physical components scores (MCS & PCS) of SF‐36 questionnaire were lower in patients with active disease in all adenoma subtypes (P < 0.03). A significant negative relationship between prolactin levels and MCS (r = −0.30, P < 0.01) and PCS (r = −0.41, P < 0.01) were found in prolactinomas. Patients with CD showed 24 hours urine‐free cortisol levels negatively correlated with MCS (r = −0.43, P < 0.01) but not with PCS. No significant correlation was found between IGF‐1 ULN and QoL scores in acromegaly. NFPA patients had lower QoL scores than patients with controlled CD, acromegaly or prolactinoma (P < 0.02). Active CD and prolactinoma have lower QoL scores in comparison of NFPA (P < 0.05). Having an adenoma, secretory or non‐functioning, decrease QoL scores in comparison of results in the healthy Mexican population register. Using an adjusted‐multivariate model, we confirmed that disease activity in all secretory adenomas is an independent risk factor, reducing SF‐36 scores significantly.
Conclusion
Activity in all secretory pituitary adenomas’ patients decrease mental and physical QoL. However, independently of disease activity, secretory and NFPA significantly decrease QoL in comparison with healthy Mexican population QoL register.
A Structural and Functional Acromegaly Classification Cuevas-Ramos, Daniel; Carmichael, John D; Cooper, Odelia ...
The journal of clinical endocrinology and metabolism,
2015-January, Letnik:
100, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Context:
GH-secreting pituitary adenomas exhibit heterogeneous natural history ranging from small tumors to large aggressive adenomas.
Objective:
To rigorously classify an acromegaly patient cohort ...defined by clinical, radiological, histopathological, and outcome characteristics.
Design:
Cross-sectional study.
Setting:
Tertiary referral pituitary center.
Patients:
Subjects were selected from a pituitary tumor research registry that includes 1178 patients with pituitary disease. Cluster analysis was performed on 338 acromegaly patients.
Interventions:
None.
Main Outcome Measures:
Biochemically active disease with elevated IGF-1 levels at follow-up.
Results:
Cluster analysis of all patients yielded 292 who were rigorously classified to three acromegaly types. Type 1 (50%) comprised older patients with the longest follow-up and most favorable outcomes, characterized by densely granulated, nonaggressive microadenomas and macroadenomas. Type 1 tumors extend to the sphenoid sinus more frequently than suprasellar extension (concave tumor image) and express abundant immunoreactive p21 and somatostatin receptor 2. Type 2 (19%) comprised noninvasive, densely or sparsely granulated macroadenomas, without significant extension (flat tumor image), with intermediate biochemical outcome. Type 3 (31%) was characterized by sparsely granulated aggressive macroadenomas and comprised patients with adverse therapeutic outcomes, despite receiving more treatments. These tumors extend to both the sphenoid sinus and suprasellar regions with commonly encountered optic chiasm compression (“peanut” magnetic resonance image), with low tumor p21 and somatostatin receptor 2 expression.
Conclusions:
After validation, this classification may be useful to accurately identify acromegaly patients with distinctive patterns of disease aggressiveness and outcome, as well as to provide an accurate tool for selection criteria in clinical studies.
Context:
Cushing disease, due to pituitary corticotroph tumor ACTH hypersecretion, drives excess adrenal cortisol production with adverse morbidity and mortality. Loss of glucocorticoid negative ...feedback on the hypothalamic-pituitary-adrenal axis leads to autonomous transcription of the corticotroph precursor hormone proopiomelanocortin (POMC), consequent ACTH overproduction, and adrenal hypercortisolism. We previously reported that R-roscovitine (CYC202, seliciclib), a 2,6,9-trisubstituted purine analog, suppresses cyclin-dependent-kinase 2/cyclin E and inhibits ACTH in mice and zebrafish. We hypothesized that intrapituitary cyclin E signaling regulates corticotroph tumor POMC transcription independently of cell cycle progression. The aim was to investigate whether R-roscovitine inhibits human ACTH in corticotroph tumors by targeting the cyclin-dependent kinase 2/cyclin E signaling pathway.
Methods:
Primary cell cultures of surgically resected human corticotroph tumors were treated with or without R-roscovitine, ACTH measured by RIA and quantitative PCR, and/or Western blot analysis performed to investigate ACTH and lineage-specific transcription factors. Cyclin E and E2F transcription factor 1 (E2F1) small interfering RNA (siRNA) transfection was performed in murine corticotroph tumor AtT20 cells to elucidate mechanisms for drug action. POMC gene promoter activity in response to R-roscovitine treatment was analyzed using luciferase reporter and chromatin immunoprecipitation assays.
Results:
R-roscovitine inhibits human corticotroph tumor POMC and Tpit/Tbx19 transcription with decreased ACTH expression. Cyclin E and E2F1 exhibit reciprocal positive regulation in corticotroph tumors. R-roscovitine disrupts E2F1 binding to the POMC gene promoter and suppresses Tpit/Tbx19 and other lineage-specific POMC transcription cofactors via E2F1-dependent and -independent pathways.
Conclusion:
R-roscovitine inhibits human pituitary corticotroph tumor ACTH by targeting the cyclin E/E2F1 pathway. Pituitary cyclin E/E2F1 signaling is a previously unappreciated molecular mechanism underlying neuroendocrine regulation of the hypothalamic-pituitary-adrenal axis, providing a subcellular therapeutic target for small molecule cyclin-dependent kinase 2 inhibitors of pituitary ACTH-dependent hypercortisolism, ie, Cushing disease.
Context:
Acromegaly is a systemic disorder caused by a GH-secreting pituitary adenoma. As with other rare diseases, acromegaly registries developed in various European countries have provided us with ...important information.
Objective:
The objective of the study was to analyze the epidemiological, clinical, biochemical, and therapeutic data from the Mexican Acromegaly Registry (MAR).
Setting:
The setting of the study was a nationwide patient registry.
Design and Methodology:
The MAR was created in 2009. It gathers data from 24 participating centers belonging to three different institutions using a specifically designed on-line platform. Only patients diagnosed after 1990 were included in the program.
Results:
A total of 2057 patients (51% female, mean age at diagnosis 41.1 ± 24.5 y) have been registered for an estimated prevalence of 18 cases per 1 million inhabitants. Hypertension, glucose intolerance, diabetes, and dyslipidemia were present in 27%, 18.4%, 30%, and 24% of the patients, respectively. The IGF-1 level at diagnosis and the concomitant presence of hypertension were significantly associated with the development of diabetes. Transsphenoidal surgery was the primary treatment in 72% of the patients. Pharmacological treatment, mostly with somatostatin analogs, was administered primarily and adjunctively in 26% and 54% of the patients, respectively. Treatment choice varied among the three participating institutions, with the predominance of pharmacological therapy in two of them and of radiation therapy in the third. Therapeutic outcomes were similar to those reported in the European registries.
Conclusions:
The MAR is the largest and first non-European registry of the disease. Our findings highlight important within-country differences in treatment choice due to variations in the availability of resources.
The MAR collects data on 2057 patients with acromegaly showing a considerable interinstitutional variation in treatment modality choice due to differences in the availability of resources.
Fibroblast growth factor 21 (FGF21) increases glucose uptake. It is unknown if FGF21 serum levels are affected by exercise.
This was a comparative longitudinal study. Anthropometric and biochemical ...evaluation were carried out before and after a bout of exercise and repeated after two weeks of daily supervised exercise. The study sample was composed of 60 sedentary young healthy women. The mean age was 24±3.7 years old, and the mean BMI was 21.4±7.0 kg/m². The anthropometric characteristics did not change after two weeks of exercise. FGF21 levels significantly increased after two weeks of exercise (276.8 ng/l (142.8-568.6) vs. (460.8 (298.2-742.1), p<0.0001)). The delta (final-basal) log of serum FGF21, adjusted for BMI, showed a significant positive correlation with basal glucose (r = 0.23, p = 0.04), mean maximal heart rate (MHR) (r = 0.54, p<0.0001), mean METs (r = 0.40, p = 0.002), delta plasma epinephrine (r = 0.53, p<0.0001) and delta plasma FFAs (r = 0.35, p = 0.006). A stepwise linear regression model showed that glucose, MHR, METs, FFAs, and epinephrine, were factors independently associated with the increment in FGF21 after the exercise program (F = 4.32; r² = 0.64, p<0.0001).
Serum FGF21 levels significantly increased after two weeks of physical activity. This increment correlated positively with clinical parameters related to the adrenergic and lipolytic response to exercise.
ClinicalTrials.gov NCT01512368.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Cushing's disease (CD) is characterized by an ACTH-producing anterior corticotrope pituitary adenoma. If hypothalamus–pituitary–adrenal (HPA) axis physiology is disrupted, ACTH secretion increases, ...which in turn stimulates adrenocortical steroidogenesis and cortisol production. Medical treatment plays an important role for patients with persistent disease after surgery, for those in whom surgery is not feasible, or while awaiting effects of radiation. Multiple drugs, with different mechanisms of action and variable efficacy and tolerability for controlling the deleterious effects of chronic glucocorticoid excess, are available. The molecular basis and clinical data for centrally acting drugs, adrenal steroidogenesis inhibitors, and glucocorticoid receptor antagonists are reviewed, as are potential novel molecules and future possible targets for CD treatment. Although progress has been made in the understanding of specific corticotrope adenoma receptor physiology and recent clinical studies have detected improved effects with a combined medical therapy approach, there is a clear need for a more efficacious and better-tolerated medical therapy for patients with CD. A better understanding of the molecular mechanisms in CD and of HPA axis physiology should advance the development of new drugs in the future.
Pituitary Infiltration by Lymphoma Tovar-Méndez, Víctor Hugo; Cuenca, Dalia; Gómez-Pérez, Francisco J ...
Journal of the Endocrine Society,
12/2022, Letnik:
6, Številka:
12
Journal Article
Recenzirano
Odprti dostop
Abstract
Lymphoma infiltration to the pituitary is rare. It represents less than 0.5% of all reported pituitary metastases (PMs). Here we present a case series of 3 patients with PMs from a systemic ...lymphoma. Also, we performed a literature review of the cases reported. We identified additional 31 cases in which non-Hodgkin lymphoma (NHL) was the most common (n = 28, 90%), with large B-cell NHL the most frequent histological subtype (n = 14, 45%). Central hypothyroidism (n = 21, 67%) was the most frequent pituitary deficiency followed by adrenal insufficiency (n = 19, 61%) and diabetes insipidus (DI; n = 18, 58%). Full endocrine recovery was found in only 12% (n = 4) of patients after treatment, and magnetic resonance imaging showed tumor regression in 22% of them. In our series, 2 patients were diagnosed with diffuse large B-cell lymphoma, and 1 had mixed cellularity of classic Hodgkin lymphoma. The mean age was 54 ± 6.92 years. Hypopituitarism and DI were present in all of them, with 100% of mortality because of advanced systemic disease.
Cushing’s syndrome is caused by excessive adrenocorticotropic hormone (ACTH) secretion derived from pituitary corticotroph tumors (Cushing disease) or from non-pituitary tumors (ectopic Cushing’s ...syndrome). Hypercortisolemic features of ectopic Cushing’s syndrome are severe, and no definitive treatment for paraneoplastic ACTH excess is available. We aimed to identify subcellular therapeutic targets by elucidating transcriptional regulation of the human ACTH precursor POMC (proopiomelanocortin) and ACTH production in non-pituitary tumor cells and in cell lines derived from patients with ectopic Cushing’s syndrome. We show that ectopic hPOMC transcription proceeds independently of pituitary-specific Tpit/Pitx1 and demonstrate a novel E2F1-mediated transcriptional mechanism regulating hPOMC. We identify an E2F1 cluster binding to the proximal hPOMC promoter region (−42 to +68), with DNA-binding activity determined by the phosphorylation at Ser-337. hPOMC mRNA expression in cancer cells was upregulated (up to 40-fold) by the co-expression of E2F1 and its heterodimer partner DP1. Direct and indirect inhibitors of E2F1 activity suppressed hPOMC gene expression and ACTH by modifying E2F1 DNA-binding activity in ectopic Cushing’s cell lines and primary tumor cells, and also suppressed paraneoplastic ACTH and cortisol levels in xenografted mice. E2F1-mediated hPOMC transcription is a potential target for suppressing ACTH production in ectopic Cushing’s syndrome.
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