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Glucose metabolism abnormalities in Cushing's syndrome: from molecular basis to clinical management
No full textAn impaired glucose metabolism, which often leads to the onset of diabetes mellitus (DM), is a common complication of chronic exposure to exogenous and endogenous glucocorticoid (GC) excess, and plays an important part in contributing to morbidity and mortality in patients with Cushing's syndrome (CS).This article reviews the pathogenesis, epidemiology, diagnosis and management of changes in glucose metabolism associated with hypercortisolism, addressing both the pathophysiological aspects and the clinical and therapeutic implications. Chronic hypercortisolism may have pleiotropic effects on all major peripheral tissues governing glucose homeostasis. Adding further complexity, both genomic and non-genomic mechanisms are directly induced by glucocorticoids (GCs) in a context-specific and cell/organ-dependent manner. In this paper, the discussion focuses on the established and potential pathological molecular mechanisms induced by chronically excessive circulating levels of GCs, affecting glucose homeostasis in various tissues.The management of patients with CS and DM includes treating their hyperglycemia and correcting their GC excess. The effects on glycemic control of various medical therapies for CS are reviewed in this paper. The association between DM and subclinical CS, and the role of screening for CS in diabetic patients are also discussed
Therapeutic strategies for Cushing's syndrome: An update
No full textntroduction: Endogenous Cushing's syndrome (CS) is a severe clinical condition caused by excess cortisol secretion. The treatment goals (with surgery, radiotherapy or medical therapy) are to normalize cortisol levels, reverse the clinical symptoms and remove the secreting neoplasm.
Areas covered: Medical treatments are increasingly used in CS, especially when surgery fails or is not indicated, or while waiting for radiotherapy to take effect. This review summarizes the different medical approaches for treating CS (adrenal- or pituitary-directed drugs, glucocorticoid receptor antagonist), alone or in combination.
Expert opinion: Adrenal steroidogenesis inhibitors have been the mainstay of medical treatment for CS: the most used are ketoconazole (or fluconazole), which inhibits adrenal steroidogenic enzymatic activities; metyrapone and LCI699 that inhibit 11 beta-hydroxylase (the latter is still an experimental compound); mitotane, used in adrenocortical carcinoma. The available glucocorticoid receptor antagonist is mifepristone, recently approved for use in controlling hyperglycemia secondary to hypercortisolism. There has recently been a lot of interest in using agents directly targeting the pituitary corticotroph cells to reduce Adreno Cortico Tropic Hormone secretion and, if possible, control the volume of pituitary adenomas. This is because corticotroph cells contain dopamine receptors (targets of bromocriptine and cabergoline), retinoic acid receptors, PPAR-gamma or somatostatin receptors, the target of the first drug developed and approved for Cushing's disease (pasireotide)
The role of an acute pasireotide suppression test in predicting response to treatment in patients with Cushing's disease: findings from a pilot study.
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Endocrine
11 December 2014, 8p
The role of an acute pasireotide suppression test in predicting response to treatment in patients with Cushing’s disease: findings from a pilot study ( Articles not published yet, but available online Article in press About articles in press (opens in a new window) )
Trementino, L.a, Zilio, M.b, Marcelli, G.a, Michetti, G.a, Barbot, M.b, Ceccato, F.b, Boscaro, M.b, Scaroni, C.b, Arnaldi, G.a
a Division of Endocrinology, University Hospital of Ancona, Polytechnic University of Marche, Via Conca 71, Torrette di Ancona, AN, Italy
b Endocrinology Unit, Department of Medicine DIMED, University-Hospital of Padua, Padua, Italy
Abstract
Pasireotide is a multireceptor-targeted somatostatin analog effective in the treatment of Cushing’s disease (CD). We evaluate the value of an acute pasireotide suppression test (PST) in predicting response to medium/long-term treatment in CD. Nineteen patients with active CD were prospectively investigated at two referral centers from May 2013 to August 2014. Follow-up data (median 6 months; range 1–9 months) were available for sixteen patients. All patients received at 09:00 h a single subcutaneous (sc) injection of 600 μg pasireotide. Serum cortisol and plasma ACTH were assessed before, and every 2 h for 8 h after, drug administration. Late-night salivary cortisol (LNSC) was assessed before and after pasireotide administration. After acute PST, all patients were continued on pasireotide 600 μg sc twice a day. During PST, cortisol and ACTH levels quickly decreased in all patients except one with a mean percentage fall, respectively, of 48.9 ± 24.3 and 48.1 ± 25.4 % compared to baseline. LNSC decreased in about 82 % of patients (14/17) achieving a normalization in five of them. Pasireotide treatment was associated with a normalization of 24-h urinary-free cortisol at last follow-up in about 68 % of patients. A fall >27 % of LNSC during PST calculated by ROC curve was the best parameter in predicting a positive response to treatment with pasireotide (sensitivity 91 %; specificity 100 %; positive predictive value 100 %; negative predictive value 75 %). Acute PST may be useful to identify CD patients who will benefit from pasireotide treatment. A LNSC fall >27 % as well as a LNSC normalization during PST is associated with a probability of 100 % of achieving a favorable response to pasireotide treatment in the medium/long term. © 2014 Springer Science+Business Media New Yor
Combination therapy for Cushing's disease: effectiveness of two schedules of treatment. Should we start with cabergoline or ketoconazole?
Full text linkCushing’s disease (CD) is associated with increased morbidity and mortality. Until now, no medical treatment has been shown to be totally satisfactory when administrated alone. This study aimed to assess the effectiveness of cabergoline with added ketoconazole and of the same combination in reverse, using urinary free cortisol (UFC) and late night salivary cortisol (LNSC) levels as biochemical markers of the treatments’ efficacy in CD patients. A prospective analysis conducted on 14 patients (f/m = 12/2; median age 52, range 33–70 years) divided into two groups: 6 patients initially treated with cabergoline for 4–6 months (rising from 0.5–1 mg/week up to 3.0 mg/week), after which ketoconazole was added (group A); and 8 patients first took ketoconazole alone for 4–6 months (rising from 200 mg/day to 600 mg/day), then cabergoline was added (group B). Patients were compared with 14 age-matched patients in prolonged remission after effective neurosurgery for CD. The combination therapy led to UFC normalization in 79 % of patients with no differences between the groups; only one patient failed to respond at all. Neither drug succeeded in controlling the disease when taken alone. LNSC dropped when compared to baseline levels, but not to a significant degree (p = 0.06), and it remained significantly higher than in controls (p = 0.0006). Associating cabergoline with ketoconazole may represent an effective second-line treatment, achieving a satisfactory reduction in UFC levels and clinical improvement. Although the combined treatment lowered patients’ LNSC levels, they remained higher than normal, indicating a persistent subclinical hypercortisolism; the implications of this condition need to be considered. No differences emerged between the two treatment schedules
Age and the metabolic syndrome affect salivary cortisol rhythm: Data from a community sample
Full text linkAbstract
OBJECTIVE:
Measurement of cortisol levels in saliva is a marker of free hormone. How salivary cortisol rhythm is affected by age, gender, the metabolic syndrome and estrogen-progestin therapy was evaluated in a community sample of adults.
SUBJECTS AND METHODS:
One hundred twenty volunteers recruited from the Hospital staff and family members of the Endocrinology Unit were instructed to collect 7 salivary samples: the first on awakening (F(0)) and 6 more (F(1.5), F(5), F(6), F(10), F(11.5) and F(14)) over the next 14 hours. Each volunteer also underwent a complete physical evaluation and a comprehensive medical history was taken. Salivary cortisol was measured using a radioimmunometric assay. Daily cortisol secretion was evaluated computing the Area Under the Curve (AUC(F0)(→)(F14)); the F(14)/F(0) ratio was calculated as a marker of cortisol rhythm.
RESULTS:
Median F(14) levels were higher in the subjects in the third tertile of age than in those falling in the second or in the first age tertile (respectively, 2.09 vs 1.33 vs 1.25 ng/mL, p=0.023 and p=0.006), in the hypertensive volunteers (2.44 vs 1.44 ng/mL, p=0.030) and in those with the metabolic syndrome (2.95 vs 1.4 ng/mL, p=0.002), with an elevated median F(14)/F(0) ratio (0.48 vs 0.19, p=0.006). According to the Kruskal-Wallis analysis of variance, the most important factor affecting F(14) value was age (p=0.001). AUC(F0)(→)(F14) was not influenced by gender, age, metabolic syndrome or estrogen-progestin therapy.
CONCLUSIONS:
While it did not affect the daily cortisol rate, late-night salivary cortisol levels were found to be increased in the subjects in the higher age tertile and in those with the metabolic syndrome
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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