Acromegaly is a systemic disease associated with increased morbidity and mortality. Most of these comorbidities can be prevented or delayed with adequate disease treatment. Although three modalities of treatment (surgery, medical treatment, and radiotherapy) are available and new drugs were approved in the last decades, there are still some patients that maintain disease activity despite treatment. Therefore, there is a need for novel therapies for acromegaly and for that purpose new formulations of currently used drugs and also new drugs are currently under study. In this review, we summarize the novel therapies for acromegaly.
Bernardo Maia, Leandro Kasuki, and Mônica R Gadelha
M Axelstad, U Hass, M Scholze, S Christiansen, A Kortenkamp, and J Boberg
Human semen quality is declining in many parts of the world, but the causes are ill defined. In rodents, impaired sperm production can be seen with early life exposure to certain endocrine-disrupting chemicals, but the effects of combined exposures are not properly investigated. In this study, we examined the effects of early exposure to the painkiller paracetamol and mixtures of human relevant endocrine-disrupting chemicals in rats. One mixture contained four estrogenic compounds; another contained eight anti-androgenic environmental chemicals and a third mixture contained estrogens, anti-androgens and paracetamol. All exposures were administered by oral gavage to time-mated Wistar dams rats (n = 16–20) throughout gestation and lactation. In the postnatal period, testicular histology was affected by the total mixture, and at the end of weaning, male testis weights were significantly increased by paracetamol and the high doses of the total and the anti-androgenic mixture, compared to controls. In all dose groups, epididymal sperm counts were reduced several months after end of exposure, i.e. at 10 months of age. Interestingly, the same pattern of effects was seen for paracetamol as for mixtures with diverse modes of action. Reduced sperm count was seen at a dose level reflecting human therapeutic exposure to paracetamol. Environmental chemical mixtures affected sperm count at the lowest mixture dose indicating an insufficient margin of safety for the most exposed humans. This causes concern for exposure of pregnant women to paracetamol as well as environmental endocrine disrupters.
Nassim Ghaffari-Tabrizi-Wizsy, Christina Angelika Passegger, Laura Nebel, Fabian Krismer, Gudrun Herzer-Schneidhofer, Gert Schwach, and Roswitha Pfragner
Preclinical trials of medullary thyroid cancer (MTC) therapeutics require both in vitro and in vivo analyses. Human tumour xenografted rodent models, which are considered the ‘gold standard’ to study and validate the efficacy and toxicity of lead compounds before translation to clinical trials, are very expensive, subject to organismal variability and ethical controversies. The avian chorioallantoic membrane (CAM) assay provides an alternative versatile, cost-effective and ethically less objectionable short-term, in vivo model for reliable screening of drugs. In this work, we grafted two MTC cell lines and patient-derived MTC tumour samples onto the avian CAM and characterised the resulted tumours histologically and immunohistochemically. Our findings provide the evidence that the CAM assay is a suitable model for studying the pathophysiology of MTC and can even be used as in vivo system for drug testing.
Maria Cristina De Martino, Richard A Feelders, Claudia Pivonello, Chiara Simeoli, Fortuna Papa, Annamaria Colao, Rosario Pivonello, and Leo J Hofland
Adrenocortical carcinomas (ACCs) are rare tumors with scant treatment options for which new treatments are required. The mTOR pathway mediates the intracellular signals of several growth factors, including the insulin-like growth factors (IGFs), and therefore represents a potential attractive pathway for the treatment of several malignancies including ACCs. Several mTOR inhibitors, including sirolimus, temsirolimus and everolimus, have been clinically developed. This review summarizes the results of the studies evaluating the expression of the mTOR pathway components in ACCs, the effects of the mTOR inhibitors alone or in combination with other drugs in preclinical models of ACCs and the early experience with the use of these compounds in the clinical setting. The mTOR pathway seems a potential target for treatment of patients with ACC, but further investigation is still required to define the potential role of mTOR inhibitors alone or in combination with other drugs in the treatment of ACC patients.
Ruixin Hu, Yanting Yuan, Chaolong Liu, Ji Zhou, Lixia Ji, and Guohui Jiang
In patients with type 2 diabetes mellitus (T2DM), the intestinal flora is out of balance and accompanied by leaky gut. The flora is characterized by an increase in mucus-degrading bacteria and a decrease in fiber-degrading bacteria. Short-chain fatty acids (SCFAs), as the major fiber-degrading bacteria fermentation, not only ameliorate the leaky gut, but also activate GPR43 to increase the mass of functional pancreatic β-cells and exert anti-inflammation effect. At present, the gut microbiota is considered as the potential target for anti-diabetes drugs, and how to reverse the imbalance of gut microbiota has become a therapeutic strategy for T2DM. This review briefly summarizes the drugs or compounds that have direct or potential therapeutic effects on T2DM by modulating the gut microbiota, including biguanides, isoquinoline alkaloids, stilbene and C7N-aminocyclic alcohols.
Anne Jouinot, Bernard Royer, Etienne Chatelut, Sotheara Moeung, Guillaume Assié, Audrey Thomas-Schoemann, Jérôme Bertherat, François Goldwasser, and Benoit Blanchet
The combination of mitotane and platinum-etoposide chemotherapy is a front-line treatment in metastatic adrenocortical carcinoma (ACC), although this regimen shows limited efficacy. Pharmacokinetic drug–drug interaction between mitotane, a strong CYP3A4 inducer, and etoposide, which is a substrate of CYP3A4, may contribute to chemoresistance. The aim of this pilot study was to assess the pharmacokinetic interaction between mitotane and etoposide in ACC patients.
Five consecutive ACC patients treated with platinum etoposide (120–150 mg/m2 day 1–2–3 at cycle 1), with or without concomitant mitotane, were included. In the absence of limiting toxicity, a dose escalation of etoposide was proposed since cycle 2. Plasma etoposide concentrations were measured using liquid chromatography at 0, 4 and 24 h after each infusion. Clearance and area under the curve (AUC) of etoposide were determined at each cycle.
Patients received two to six chemotherapy cycles, in association with mitotane (N = 4) or after mitotane discontinuation (N = 1). Etoposide clearance was two-fold higher with concomitant mitotane (4.95 L/h) than after mitotane discontinuation (2.53 L/h, P = 0.014), and 2.5-fold higher than that in reference population not treated with mitotane (1.81 L/h). Etoposide dose escalation was performed in four patients under mitotane, resulting in two minor tumor responses and one severe toxicity (febrile aplasia) at dose of 300 mg/m2/day. Tumor response was associated with higher etoposide AUC (267.3 vs 188.8 mg.h/L, P = 0.04).
A drug–drug interaction between mitotane and etoposide may contribute to the low efficacy of platinum-etoposide chemotherapy. This pilot study suggests further a potential benefit of increasing etoposide dose in ACC patients receiving mitotane.
A variety of endocrine and metabolic signals regulate pituitary cell function acting through the hypothalamus-pituitary neuroendocrine axes or directly at the pituitary level. The underlying intracellular transduction mechanisms in pituitary cells are still debated. AMP-activated protein kinase (AMPK) functions as a cellular sensor of low energy stores in all mammalian cells and promotes adaptive changes in response to calorie restriction. It is also regarded as a target for therapy of proliferative disorders. Various hormones and drugs can promote tissue-specific activation or inhibition of AMPK by enhancing or inhibiting AMPK phosphorylation, respectively. This review explores the preclinical studies published in the last decade that investigate the role of AMP-activated protein kinase in the intracellular transduction pathways downstream of endocrine and metabolic signals or drugs affecting pituitary cell function, and its role as a target for drug therapy of pituitary proliferative disorders. The effects of the hypoglycemic agent metformin, which is an indirect AMPK activator, are discussed. The multiple effects of metformin on cell metabolism and cell signalling and ultimately on cell function may be either dependent or independent of AMPK. The in vitro effects of metformin may also help highlighting differences in metabolic requirements between pituitary adenomatous cells and normal cells.
Sarmistha Banerjee, Allison M Hayes, and Bernard H Shapiro
The sexually dimorphic expression of cytochromes P450 (CYP) drug metabolizing enzymes has been reported in all species examined. These sex differences are initially expressed during puberty and are solely regulated by sex differences in the circulating growth hormone (GH) profiles. Once established, however, the different male- and female-dependent CYP isoforms are permanent and immutable, suggesting that adult CYP expression requires imprinting. Since the hormone that regulates an adult function is likely the same hormone that imprints the function, we selectively blocked GH secretion in some newborn male rats while others also received a concurrent physiologic replacement of rat GH. Rats were subsequently challenged, peripubertally, with either a masculine-like episodic GH regimen or the GH vehicle alone. The results demonstrate that episodic GH regulation of male-specific CYP2C11 and CYP3A2, as well as female-predominant CYP2C6, are dependent on developmental GH imprinting. Moreover, the induction and/or activation of major components in the signal transduction pathway regulating the expression of the principal CYP2C11 isoform is obligatorily dependent on perinatal GH imprinting without which CYP2C11 and drug metabolism would be permanently and profoundly suppressed. Since there are additional adult metabolic functions also regulated by GH, pediatric drug therapy that is known to disrupt GH secretion could unintentionally impair adult health.
Jean-Benoît Corcuff, Laurence Chardon, Ines El Hajji Ridah, and Julie Brossaud
Biogenic amines such as 5-hydroxy-indole acetic acid (5HIAA) the main metabolite of serotonin or metanephrines (catecholamines metabolites) are used as biomarkers of neuroendocrine tumours.
To re-evaluate the recommendations for urinary sampling (preservatives, diet, drugs, etc.) as many of the reported analytical interferences supporting these recommendations are related to obsolete assays.
Bibliographic analysis of old and modern assays concerning preservation, extraction, assay and interferences.
5HIAA may degrade as soon as urine is excreted. Thus, acids as preservatives (hydrochloric or acetic acid) have to be immediately added. Care should be taken not to decrease the pH under 2. Urine preservative for metanephrine assays is not mandatory. Diets including serotonin-, tryptophan- and dopamine-rich foods have to be avoided depending on the biomarkers investigated (bananas, plantain, nuts, etc.). Tryptophan-rich over-the-counter formulas have to be prohibited when 5HIAA has to be assayed. Acetaminophen may interfere with electrochemical detection depending on high-pressure liquid chromatography (HPLC) parameters. No interference is known with mass spectrometric assays but with the one described for metanephrines determination. Some drugs interfere however with serotonin and catecholamines secretion and/or metabolism (monoamine oxidase inhibitors, serotonin or dopamine recapture inhibitors, etc.).
Revisited recommendations are provided for the diet, the drugs and the preservatives before HPLC coupled with electrochemical and mass spectrometry assays.
Lijin Ji, Na Yi, Qi Zhang, Shuo Zhang, Xiaoxia Liu, Hongli Shi, and Bin Lu
To assess the current management of prolactinoma among endocrinologists in China.
An online survey of a large sample of endocrinologists was conducted in China. The questionnaire included 21 questions related to controversial issues about the management of prolactinomas. Doctors in the endocrinology department of a university-affiliated hospital or a comprehensive secondary hospital in 12 cities from East, West, South, North and Middle China were surveyed.
A total of 290 valid questionnaires were collected, and the response rate was 40%. When hyperprolactinemia occurred, 97% of the respondents would test thyroid-stimulating hormone routinely. 22% of the respondents considered that prolactin levels <100 ng/mL exclude the presence of a prolactinoma. Only 9% of the respondents believed that prolactin >250 ng/mL could occur in all the following situations as macroprolactinoma, mircoprolactinoma, macroprolactinemia and drug-induced hyperprolactinemia. Surgery was not recommended by 272 (94%) endocrinologists as the first choice for treating microprolactinomas. 58% and 92% of endocrinologists would start drug treatment for microprolactinomas and macroprolactinomas at diagnosis. 70% and 40% chose to withdraw treatment after 2–3 years of prolactin normalization in microprolactinomas and macroprolactinomas. In case of pregnancy, 57% of the respondents considered bromocriptine as choice for women patients. Drug discontinuation after pregnancy was advocated in 63% and 27% for microprolactinoma and macroprolactinoma. Moreover, 44% of endocrinologists believed that breastfeeding was allowable in both micro- and macroprolactinoma.
This is the first study to investigate the management of prolactinomas among endocrinologists in China. We found that the current clinical treatment was not uniform. Therefore, it is necessary to strengthen the training of endocrinologists to improve clinical diagnosis and treatment practices.