144 results on '"Feelders, R A"'
Search Results
102. Treatment of patients with gastro-entero-pancreatic (GEP) tumours with the novel radiolabelled somatostatin analogue [[sup 177] Lu-DOTA[sup 0] ,Tyr[sup 3] ]octreotate.
- Author
-
Kwekkeboom, D. J., Bakker, W. H., Kam, B. L., Teunissen, J. J. M., Kooij, P. P. M., de Herder, W. W., Feelders, R. A., van Eijck, C. H. J., de Jong, M., Srinivasan, A., Erion, J. L., and Krenning, E. P.
- Subjects
NEUROENDOCRINE tumors ,DRUG therapy ,SOMATOSTATIN ,TUMOR treatment - Abstract
Medical treatment and chemotherapy are seldom successful in achieving objective tumour reduction in patients with metastatic neuroendocrine tumours. Treatment with the radiolabelled somatostatin analogue [[SUP90]Y-DOTA[SUP0],Tyr[SUP3]octreotide may result in partial remissions in 10-25% of patients. The newer analogue [DOTA[SUP0],Tyr[SUP3]]octreotate (octreotate) has a ninefold higher affinity for the somatostatin receptor subtype 2 as compared with [DOTA[SUP0],Tyr[SUP3] octreotide. Also, labelled with the beta- and gamma-emitting radionuclide [SUP177]Lu, it has proved very successful in achieving tumour regression in animal models. The effects of [SUP177]Lu-octreotate therapy were studied in 35 patients with neuroendocrine gastro-entero-pancreatic (GEP) tumours who underwent follow-up for 3-6 months after receiving their final dose. Patients were treated with doses of 100, 150 or 200 mCi [SUP177]Lu-octreotate, to a final cumulative dose of 600-800 mCi, with treatment intervals of 6-9 weeks. Nausea and vomiting within the first 24 h after administration were present in 30% and 14% of the administrations, respectively. WHO toxicity grade 3 anaemia, leucocytopenia and thrombocytopenia occurred after 0%, 1% and 1% of the administrations, respectively. Serum creatinine and creatinine clearance did not change significantly. The effects of the therapy on tumour size were evaluable in 34 patients. Three months after the final administration, complete remission was found in one patient (3%), partial remission in 12 (35%), stable disease in 14 (41%) and progressive disease in seven (21%), including three patients who died during the treatment period. Tumour response was positively correlated with a high uptake on the octreoscan, limited hepatic tumour mass and a high Karnofsky Performance Score. Because of the limited efficacy of alternative therapies, many physicians currently adopt an expectant attitude when dealing with patients with metastatic GEP tumours. However,... [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
103. Transferrin microheterogeneity as a probe in normal and disease states
- Author
-
Jong, G., Feelders, R., Noort, W., and Eijk, H.
- Abstract
Isoelectric focusing of iron saturated serum has been established as a convenient method for showing transferrin glycan microheterogeneity. In a clinical setting, the method is used in the detection of cerebrospinal fluid leakage, the screening for surreptitious alcohol abuse and in the diagnosis of the carbohydrate deficient glycoprotein syndrome. In normal physiological states it can also be used as a tool to probe for changes in N-glycosylation.
- Published
- 1995
- Full Text
- View/download PDF
104. Chromogranin A, Ki-67 index and IGF-related genes in patients with neuroendocrine tumors
- Author
-
Roxanne Adrichem, Leo Hofland, Feelders, R. A., Maria Cristina De Martino, Peter van Koetsveld, Casper Van Eijck, Ronald de Krijger, Diana Mooij, Janssen, Joseph A. M. J. L., Wouter de Herder, Internal Medicine, Surgery, and Pathology
105. Prevalence, Clinical Management, and Natural Course of Incidental Findings on Brain MR Images: The Population-based Rotterdam Scan Study
- Author
-
Daniel Bos, Marielle Poels, Hieab Adams, Saloua Akoudad, Lotte Cremers, Hazel Zonneveld, Jory Hoogendam, Ben Verhaaren, Vincent Verlinden, Jasper Verbruggen, Abbas Peymani, Bert Hofman, Gabriel Krestin, Arnaud Vincent, Feelders, R. A., Peter Koudstaal, Aad van der Lugt, Arfan Ikram, M., Meike Vernooij, Epidemiology, Radiology & Nuclear Medicine, Neurology, Neurosurgery, and Internal Medicine
106. Telomerase reverse transcriptase promoter mutations in tumors originating from the adrenal gland and extra-adrenal paraganglia
- Author
-
Thomas Papathomas, Lindsey Oudijk, Ellen Zwarthoff, Edward Post, Floor Duijkers, Max van Noesel, Leo Hofland, Pj, Pollard, Er, Maher, David Restuccia, Feelders, R. A., Gaston Franssen, Hj, Timmers, Stefan Sleijfer, Wouter de Herder, Ronald de Krijger, Winand Dinjens, Esther Korpershoek, Pathology, Pediatrics, Internal Medicine, Surgery, and Medical Oncology
107. Thoracic and Gastroenteropancreatic (GEP) Neuroendocrine Tumors (NETs) and Ectopic Adrenocorticotropin (ACTH) Syndrome (EAS).
- Author
-
Kamp, K., Alwani, A., Feelders, R., and De Herder, W.
- Subjects
ADRENOCORTICAL hormones ,ADRENOCORTICOTROPIC hormone ,CUSHING'S syndrome ,CARCINOID ,PANCREATIC diseases - Abstract
Introduction: Ectopic Adrenocorticotropin (ACTH) Syndrome (EAS) is associated with a variety of malignancies, mostly of neuroendocrine origin. Several series report on the relative contribution of EAS in the spectrum of Cushing's syndrome. However, information on the incidence/prevalence of EAS in the setting of patients diagnosed with thoracic or gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) is virtually absent. Aim(s): Screening of a large consecutive series of Thoracic NET or GEP NET patients for the presence/occurrence of EAS in a retrospective case-record study in a Tertiary academic referral centre. Materials and methods: Four-hundred and ninety-one patients diagnosed with thoracic or GEP NETs between 2000-2009 were studied. We differentiated between previous, synchronous and metachronous occurrence of EAS. Synchronous EAS was defined as occurring between six months before and six months after first diagnosis of the thoracic or GEP NET. MEN1 and SCLC were excluded. Results: Of 491 patients with thoracic and GEP NETs [258 males, 233 females; female to male ratio, 1.1:1; mean age, 58.1 years] 10 patients (2.0%) had EAS [five males, seven females; mean age, 53.1 years]. All patients had synchronous EAS. Five patients had a bronchial NET, three had a thymic NET and two had a pancreatic NET. Conclusion: The incidence of EAS in patients with thoracic and GEP NETs is very low (2.0%). Thoracic NETs (thymis and bronchial carcinoids) were the most frequent cause of EAS. Pancreatic NETs are the most common GEP-NETs causing EAS. [ABSTRACT FROM AUTHOR]
- Published
- 2012
108. Adaptation of transferrin protein and glycan synthesis
- Author
-
Jong, G. De, Noort, W. L. Van, Feelders, R. A., and Jeu-Jaspars, C. M. H. De
- Published
- 1992
- Full Text
- View/download PDF
109. Efficacy and safety of levoketoconazole in the treatment of endogenous Cushing's syndrome (SONICS): a phase 3, multicentre, open-label, single-arm trial
- Author
-
Pivonello R, Elenkova A, Fleseriu M, Cohen F, Geer Eb, P. Witek, Roberto Salvatori, Auchus Rj, Greenman Y, Biller Bmk, Feelders Ra, Fleseriu, M., Pivonello, R., Elenkova, A., Salvatori, R., Auchus, R. J., Feelders, R. A., Geer, E. B., Greenman, Y., Witek, P., Cohen, F., Biller, B. M. K., and Internal Medicine
- Subjects
Adult ,Male ,medicine.medical_specialty ,Adolescent ,Hydrocortisone ,Endocrinology, Diabetes and Metabolism ,Population ,Urology ,Phase (waves) ,Endogeny ,030209 endocrinology & metabolism ,QT interval ,law.invention ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Endocrinology ,Randomized controlled trial ,law ,Internal medicine ,Internal Medicine ,Adrenal insufficiency ,medicine ,Humans ,030212 general & internal medicine ,Adverse effect ,education ,Cushing Syndrome ,Aged ,Levoketoconazole, Cushing's syndrome, Levoketoconazole efficacy, Levoketoconazole safety ,education.field_of_study ,business.industry ,Alanine Transaminase ,Middle Aged ,medicine.disease ,Discontinuation ,Long QT Syndrome ,Ketoconazole ,Treatment Outcome ,Tolerability ,Female ,Chemical and Drug Induced Liver Injury ,Open label ,business ,Adrenal Insufficiency ,medicine.drug - Abstract
Summary Background Levoketoconazole is a ketoconazole stereoisomer in development for treatment of Cushing's syndrome and has not been assessed previously in a clinical trial in patients with Cushing's syndrome. We aimed to investigate the efficacy and safety of levoketoconazole in patients with endogenous Cushing's syndrome. Methods SONICS is a phase 3, multicentre, open-label, non-randomised, single-arm study in which we recruited adults (≥18 years) with confirmed Cushing's syndrome and a mean 24-h urinary free cortisol (mUFC) of at least 1·5 times the upper limit of normal from 60 hospital and community sites in 19 countries (15 countries in Europe, and Canada, Israel, Turkey, and the USA). Patients were treated with oral levoketoconazole in a 2–21 week incremental dose-titration phase starting at 150 mg twice daily (150 mg increments until mUFC normalisation, maximum 600 mg twice daily) and a 6-month maintenance phase. The primary outcome was the proportion of patients with mUFC normalisation at end of maintenance, without dose increase during the maintenance phase (in the intention-to-treat population). Prespecified adverse events of special interest were potential liver toxicity, corrected QT prolongation, and adrenal insufficiency. This trial is registered with ClinicalTrials.gov , NCT01838551 . Findings Between July 30, 2014, and June 30, 2017, 201 individuals were screened and 94 patients were enrolled and received at least one dose of study medication. Of the 94 patients, 80 (85%) had pituitary Cushing's syndrome. Mean mUFC at baseline was 671·4 nmol/24 h (243·3 μg/24 h), which is 4·9 times the upper limit of normal. Of the 77 patients who advanced to the maintenance phase, 62 (81%) had mUFC normalisation by end-of-dose titration. At the end of the 6-month maintenance phase, 29 (31%) of 94 patients were responders; the least-squares mean estimate of the proportion of responders was 0·30 (95% CI 0·21–0·40; p=0·0154 vs null hypothesis of ≤0·20). The most common adverse events in the 94 patients were nausea (30 [32%]) and headache (26 [28%]). Adverse events led to study discontinuation in 12 (13%) of 94 patients. Two patients had a QT interval (Fridericia corrected) of more than 500 ms, and three patients had suspected adrenal insufficiency. Alanine aminotransferase reversibly increased to more than three times the upper limit of normal in ten (11%) patients. Four patients had serious adverse events that were considered probably or definitely related to the study drug: abnormal liver function test results (n=1), prolonged QT interval (n=2), and adrenal insufficiency (n=1). One person died from colon carcinoma unrelated to study medication. Interpretation Twice-daily oral levoketoconazole treatment led to sustained improvements in urinary free cortisol, with an acceptable safety and tolerability profile. Levoketoconazole might represent a useful therapeutic option for the medical treatment of Cushing's syndrome. Funding Strongbridge Biopharma.
- Published
- 2019
- Full Text
- View/download PDF
110. Relacorilant, a Selective Glucocorticoid Receptor Modulator, Induces Clinical Improvements in Patients With Cushing Syndrome: Results From A Prospective, Open-Label Phase 2 Study
- Author
-
Murray B. Gordon, Andreas G. Moraitis, Janice M. Kerr, Rosario Pivonello, Atil Y. Kargi, Noel Ellison, Massimo Terzolo, Cary N. Mariash, Irina Bancos, Richard A Feelders, Internal Medicine, Pivonello, R., Bancos, I., Feelders, R. A., Kargi, A. Y., Kerr, J. M., Gordon, M. B., Mariash, C. N., Terzolo, M., Ellison, N., and Moraitis, A. G.
- Subjects
Male ,Pyridines ,Endocrinology, Diabetes and Metabolism ,Pyridine ,Peripheral edema ,030204 cardiovascular system & hematology ,Gastroenterology ,Impaired glucose tolerance ,Cushing syndrome ,Endocrinology ,0302 clinical medicine ,Receptors ,Prospective Studies ,clinical trial ,Middle Aged ,Prognosis ,Hypokalemia ,Female ,cortisol ,glucocorticoid ,hypercortisolism ,hyperglycemia ,hypertension ,relacorilant ,Cushing Syndrome ,Diabetes Mellitus, Type 2 ,Follow-Up Studies ,Humans ,Hyperglycemia ,Hypertension ,Isoquinolines ,Pyrazoles ,Receptors, Glucocorticoid ,medicine.symptom ,Glucocorticoid ,Type 2 ,medicine.drug ,Human ,medicine.medical_specialty ,Nausea ,Prognosi ,030209 endocrinology & metabolism ,Diseases of the endocrine glands. Clinical endocrinology ,Follow-Up Studie ,03 medical and health sciences ,SDG 3 - Good Health and Well-being ,Internal medicine ,medicine ,Diabetes Mellitus ,Adverse effect ,Isoquinoline ,business.industry ,RC648-665 ,medicine.disease ,Prospective Studie ,Blood pressure ,Pyrazole ,business - Abstract
Introduction/PurposeRelacorilant is a selective glucocorticoid receptor modulator (SGRM) with no progesterone receptor activity. We evaluated the efficacy and safety of relacorilant in patients with endogenous Cushing syndrome (CS).Materials and MethodsA single-arm, open-label, phase 2, dose-finding study with 2 dose groups (NCT02804750, https://clinicaltrials.gov/ct2/show/NCT02804750) was conducted at 19 sites in the U.S. and Europe. Low-dose relacorilant (100-200 mg/d; n = 17) was administered for 12 weeks or high-dose relacorilant (250-400 mg/d; n = 18) for 16 weeks; doses were up-titrated by 50 mg every 4 weeks. Outcome measures included proportion of patients with clinically meaningful changes in hypertension and/or hyperglycemia from baseline to last observed visit. For patients with hypertension, clinical response was defined as a ≥5-mmHg decrease in mean systolic or diastolic blood pressure, measured by a standardized and validated 24-h ABPM. For patients with hyperglycemia, clinical response was defined ad-hoc as ≥0.5% decrease in HbA1c, normalization or ≥50-mg/dL decrease in 2-h plasma glucose value on oral glucose tolerance test, or decrease in daily insulin (≥25%) or sulfonylurea dose (≥50%).Results35 adults with CS and hypertension and/or hyperglycemia (impaired glucose tolerance or type 2 diabetes mellitus) were enrolled, of which 34 (24 women/10 men) received treatment and had postbaseline data. In the low-dose group, 5/12 patients (41.7%) with hypertension and 2/13 patients (15.4%) with hyperglycemia achieved response. In the high-dose group, 7/11 patients (63.6%) with hypertension and 6/12 patients (50%) with hyperglycemia achieved response. Common (≥20%) adverse events included back pain, headache, peripheral edema, nausea, pain at extremities, diarrhea, and dizziness. No drug-induced vaginal bleeding or hypokalemia occurred.ConclusionsThe SGRM relacorilant provided clinical benefit to patients with CS without undesirable antiprogesterone effects or drug-induced hypokalemia.
- Published
- 2021
111. Levoketoconazole in the Treatment of Patients With Cushing’s Syndrome and Diabetes Mellitus: Results From the SONICS Phase 3 Study
- Author
-
Yona Greenman, Leonard Saiegh, Przemysław Witek, Atanaska Elenkova, Paola Perotti, Fredric J. Cohen, Richard A Feelders, Rosario Pivonello, Maria Fleseriu, Giorgio Arnaldi, Eliza B Geer, Pivonello, R., Elenkova, A., Fleseriu, M., Feelders, R. A., Witek, P., Greenman, Y., Geer, E. B., Perotti, P., Saiegh, L., Cohen, F., and Arnaldi, G.
- Subjects
Blood Glucose ,Male ,Endocrinology, Diabetes and Metabolism ,Phases of clinical research ,030204 cardiovascular system & hematology ,lcsh:Diseases of the endocrine glands. Clinical endocrinology ,Gastroenterology ,Endocrinology ,0302 clinical medicine ,Diabetes Complication ,Enzyme Inhibitor ,Medicine ,Prospective Studies ,Enzyme Inhibitors ,Cushing Syndrome ,education.field_of_study ,diabetes mellitu ,Cushing’s disease ,Middle Aged ,Clinical Trial ,Ketoconazole ,Treatment Outcome ,diabetes mellitus ,Vomiting ,Female ,medicine.symptom ,Human ,medicine.drug ,Adult ,medicine.medical_specialty ,Nausea ,Population ,030209 endocrinology & metabolism ,levoketoconazole ,Diabetes Complications ,03 medical and health sciences ,Internal medicine ,Diabetes mellitus ,Humans ,Adverse effect ,education ,Aged ,lcsh:RC648-665 ,hypercortisolism ,business.industry ,Cushing's disease ,Cushing’s syndrome ,medicine.disease ,Prospective Studie ,business - Abstract
BackgroundCushing’s syndrome (CS) is associated with numerous comorbidities, including diabetes mellitus (DM). Levoketoconazole, an orally administered ketoconazole stereoisomer, is in clinical trials for the treatment of CS.MethodsSONICS, a prospective, open-label, phase 3 study in adults with confirmed CS and mean 24-h urinary free cortisol (mUFC) ≥1.5× ULN, included dose-titration, 6-month maintenance, and 6-month extension phases. This subanalysis evaluated the efficacy of levoketoconazole in patients with DM (n = 28) or without DM (n = 49) who entered the maintenance phase. Safety was evaluated in the overall population (N = 94) during the dose-titration and maintenance phases.ResultsNormalization of mUFC at the end of maintenance phase (EoM), without a dose increase during maintenance (SONICS primary endpoint) was observed in 46% of patients with DM (95% CI, 28 to 66%; P = 0.0006 vs null hypothesis of ≤20%) and 33% of patients without DM (95% CI, 20 to 48%; P = 0.0209). At EoM, mean HbA1c decreased from 6.9% at baseline to 6.2% in patients with DM and from 5.5 to 5.3% in patients without DM. Mean fasting blood glucose decreased from 6.85 mmol/L (123.4 mg/dl) to 5.82 mmol/L (104.9 mg/dl) and from 5.11 mmol/L (92.1 mg/dl) to 4.66 mmol/L (84.0 mg/dl) in patients with and without DM, respectively. Adverse events that were more common in patients with DM included nausea (58.3%), vomiting (19.4%), and urinary tract infection (16.7%); none prompted study drug withdrawal.ConclusionsTreatment with levoketoconazole led to sustained normalization of mUFC and improvement in glycemic control that was more pronounced in patients with DM.Clinical Trial Registration(ClinicalTrials.gov), NCT01838551.
- Published
- 2021
- Full Text
- View/download PDF
112. IGF and mTOR pathway expression and in vitro effects of linsitinib and mTOR inhibitors in adrenocortical cancer
- Author
-
Leo J. Hofland, Maria Cristina De Martino, Claudia Pivonello, Ronald R. de Krijger, Annamaria Colao, Richard A Feelders, Fadime Dogan, Wouter W. de Herder, Davine Hofste op Bruinink, Rosario Pivonello, Peter M. van Koetsveld, Joseph A M J L Janssen, A. Marlijn Waaijers, De Martino, M. C., van Koetsveld, P. M., Feelders, R. A., de Herder, W. W., Dogan, F., Janssen, J. A. M. J. L., Hofste op Bruinink, D., Pivonello, C., Waaijers, A. M., Colao, A., de Krijger, R. R., Pivonello, R., Hofland, L. J., Internal Medicine, and Erasmus MC other
- Subjects
Male ,Linsitinib ,Endocrinology, Diabetes and Metabolism ,Antineoplastic Agents ,Apoptosis ,030209 endocrinology & metabolism ,Receptor, IGF Type 1 ,Adrenocortical cancer ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Endocrinology ,SDG 3 - Good Health and Well-being ,Cell Line, Tumor ,Adrenocortical Carcinoma ,medicine ,Humans ,Adrenocortical carcinoma ,Insulin-Like Growth Factor I ,Adrenal ,IGF ,Child ,Protein Kinase Inhibitors ,PI3K/AKT/mTOR pathway ,Cell Proliferation ,Insulin-like growth factor 1 receptor ,Everolimus ,biology ,Cell growth ,TOR Serine-Threonine Kinases ,Imidazoles ,medicine.disease ,Adrenal Cortex Neoplasms ,Diabetes and Metabolism ,Insulin receptor ,chemistry ,Child, Preschool ,Pyrazines ,030220 oncology & carcinogenesis ,Sirolimus ,Adrenal Cortex ,Cancer research ,biology.protein ,Original Article ,Female ,Signal Transduction ,medicine.drug - Abstract
Purpose: The IGF and mTOR-pathways are considered as potential targets for therapy in patients with adrenocortical carcinoma (ACC). This study aims to describe the IGF pathway in ACC and to explore the response to the combined treatment with the IGF1R/IR inhibitor linsitinib, and mTOR inhibitors (sirolimus and everolimus) in in vitro models of ACC. Methods: The protein expression level of IGF2, IGF1R and IGF2R was evaluated by immunohistochemistry in 17 human ACCs and the mRNA expression level of IGF1, IGF2, IGF1R, IR isoforms A and B, IGF2R, IGF-Binding-Proteins[IGFBP]-1, 2, 3 and 6 was evaluated by RT-qPCR in 12 samples. In H295R and HAC15 ACC cell lines the combined effects of linsitinib and sirolimus or everolimus on cell survival were evaluated. Results: A high protein expression of IGF2, IGF1R and IGF2R was observed in 82, 65 and 100% of samples, respectively. A high relative expression of IGF2 mRNA was found in the majority of samples. The mRNA levels of the IRA were higher than that of IRB and IGF1R in the majority of samples (75%). Linsitinib inhibits cell growth in the H295R and HAC15 cell lines and, combined with sirolimus or everolimus, linsitinib showed a significant additive effect. Conclusions: In addition to IGF2 and IGF1R, ACC express IGF2R, IRA and several IGFBPs, suggesting that the interplay between the different components of the IGF pathway in ACC could be more complex than previously considered. The addition of mTOR inhibitors to linsitinib may have stronger antiproliferative effects than linsitinib alone.
- Published
- 2019
113. Combined therapy with somatostatin analogues and weekly pegvisomant in active acromegaly.
- Author
-
Feenstra J, de Herder WW, ten Have SMT, van den Beld AW, Feelders RA, Janssen JAM, van der Lely AJ, Feenstra, J, de Herder, W W, ten Have, S M T H, van den Beld, A W, Feelders, R A, Janssen, J A M J L, and van der Lely, A J
- Abstract
Pegvisomant monotherapy once daily returns concentrations of insulin-like growth factor I (IGF-I) to normal in most patients with acromegaly, but is very costly. In a 42-week dose-finding study, we assessed the efficacy of the combination of long-acting somatostatin analogues once monthly and pegvisomant once weekly in 26 patients with active acromegaly. Dose of pegvisomant was increased until IGF-I concentration became normal or until a weekly dose of 80 mg was reached. IGF-I reached normal concentrations in 18 of 19 (95%) patients who completed 42 weeks of treatment, with a median weekly dose of 60 mg pegvisomant (range 40-80). No signs of pituitary tumour growth were noted, but mild increases in liver enzymes were observed in ten patients (38%). This combined treatment is effective, might increase compliance, and could greatly reduce the costs of medical treatment for acromegaly in some patients. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
114. The role of mTOR pathway as target for treatment in adrenocortical cancer
- Author
-
Leo J. Hofland, Chiara Simeoli, Annamaria Colao, Claudia Pivonello, Maria Cristina De Martino, Richard A Feelders, Rosario Pivonello, Fortuna Papa, Internal Medicine, De Martino, M. C., Feelders, R. A., Pivonello, C., Simeoli, C., Papa, F., Colao, A., Pivonello, R., and Hofland, L. J.
- Subjects
Endocrinology, Diabetes and Metabolism ,Endocrine cancer ,030209 endocrinology & metabolism ,Review ,Neuroendocrinology ,lcsh:Diseases of the endocrine glands. Clinical endocrinology ,behavioral disciplines and activities ,03 medical and health sciences ,0302 clinical medicine ,Endocrinology ,endocrine cancers ,SDG 3 - Good Health and Well-being ,growth factors ,Internal Medicine ,medicine ,PI3K/AKT/mTOR pathway ,lcsh:RC648-665 ,Everolimus ,business.industry ,Treatment options ,Growth factor ,Temsirolimus ,nervous system ,adrenal ,030220 oncology & carcinogenesis ,Sirolimus ,neuroendocrinology ,Cancer research ,business ,Adrenocortical cancer ,human activities ,Intracellular ,medicine.drug - Abstract
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.
115. Venous thromboembolism in Cushing syndrome: results from an EuRRECa and Endo-ERN survey.
- Author
-
Cherenko M, Appelman-Dijkstra NM, Priego Zurita AL, Biermasz NR, Dekkers OM, Klok FA, Reisch N, Aulinas A, Biagetti B, Cannavo S, Canu L, Detomas M, Devuyst F, Falhammar H, Feelders RA, Ferrau F, Gatto F, Grasselli C, van Houten P, Hoybye C, Isidori AM, Kyrilli A, Loli P, Maiter D, Nowak E, Pivonello R, Ragnarsson O, Steenaard RV, Unger N, van de Ven A, Webb SM, Yeste D, Ahmed SF, and Pereira AM
- Abstract
Background: Patients with Cushing syndrome (CS) are at increased risk of venous thromboembolism (VTE)., Objective: The aim was to evaluate the current management of new cases of CS with a focus on VTE and thromboprophylaxis., Design and Methods: A survey was conducted within those that report in the electronic reporting tool (e-REC) of the European Registries for Rare Endocrine Conditions (EuRRECa) and the involved main thematic groups (MTG's) of the European Reference Networks for Rare Endocrine Disorders (Endo-ERN) on new patients with CS from January 2021 to July 2022., Results: Of 222 patients (mean age 44 years, 165 females), 141 patients had Cushing disease (64%), 69 adrenal CS (31%), and 12 patients with ectopic CS (5.4%). The mean follow-up period post-CS diagnosis was 15 months (range 3-30). Cortisol-lowering medications were initiated in 38% of patients. One hundred fifty-four patients (69%) received thromboprophylaxis (including patients on chronic anticoagulant treatment), of which low-molecular-weight heparins were used in 96% of cases. VTE was reported in six patients (2.7%), of which one was fatal: two long before CS diagnosis, two between diagnosis and surgery, and two postoperatively. Three patients were using thromboprophylaxis at time of the VTE diagnosis. The incidence rate of VTE in patients after Cushing syndrome diagnosis in our study cohort was 14.6 (95% CI 5.5; 38.6) per 1000 person-years., Conclusion: Thirty percent of patients with CS did not receive preoperative thromboprophylaxis during their active disease stage, and half of the VTE cases even occurred during this stage despite thromboprophylaxis. Prospective trials to establish the optimal thromboprophylaxis strategy in CS patients are highly needed., Significance Statement: The incidence rate of venous thromboembolism in our study cohort was 14.6 (95% CI 5.5; 38.6) per 1000 person-years. Notably, this survey showed that there is great heterogeneity regarding time of initiation and duration of thromboprophylaxis in expert centers throughout Europe.
- Published
- 2024
- Full Text
- View/download PDF
116. Midgut neuroendocrine tumor patients have a depleted gut microbiome with a discriminative signature.
- Author
-
Mulders MCF, Audhoe AS, Van Koetsveld PM, Feelders RA, Hofland LJ, de Herder WW, Kraaij R, and Hofland J
- Subjects
- Humans, Gastrointestinal Microbiome, Neuroendocrine Tumors, Intestinal Neoplasms, Carcinoid Tumor
- Abstract
Rationale: When compared to other types of cancer, the prevalence of midgut neuroendocrine tumors (NET) has disproportionally increased over the past decades. To date, there has been very little progress in discovering (epi)genetic drivers and treatment options for these tumors. Recent microbiome research has revealed that enteroendocrine cells communicate with the intestinal microbiome and has provided novel treatment targets for various other cancer types. Hence, our aim was to analyze the role of the gut microbiome in midgut NET patients., Methods: Fecal samples, prospectively collected from patients and control subjects, were analyzed with next generation 16S sequencing. Patients with neuroendocrine carcinomas and recent antibiotics use were excluded. Relevant variables were extracted from questionnaires and electronic health records. Microbial composition was compared between patients and controls as well as between groups within the patient cohort., Results: 87 midgut NET patients and 95 controls were included. Midgut NET patients had a less rich and diverse gut microbiome than controls (p < 0.001). Moreover, we identified 31 differentially abundant species and a gut microbial signature consisting of 17 species that was predictive of midgut NET presence with an area under the receiver operating characteristic curve of 0.863. Gut microbial composition was not directly associated with the presence of the carcinoid syndrome, tumor grade or multifocality. Nonetheless, we did observe a potential link between microbial diversity and the presence of carcinoid syndrome symptoms within the subset of patients with elevated 5-hydroxyindolacetic acid levels., Conclusion: Midgut NET patients have an altered gut microbiome which suggests a role in NET development and could provide novel targets for microbiome-based diagnostics and therapeutics., Competing Interests: Declaration of Competing Interest AA, PK, RF, LH and RK have no potential conflict of interest. MM has received a travel fee from Ipsen. JH has received speaker or consultancy fees from Novartis, Ipsen and Serb. WWH has received travel or speaker fees from Novartis, Ipsen, Camurus and Advanced Accelerator Applications, research funds from Ipsen and is on the Advisory Boards of Novartis and of Ipsen., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2024
- Full Text
- View/download PDF
117. Epigenetic regulation of somatostatin and somatostatin receptors in neuroendocrine tumors and other types of cancer.
- Author
-
Klomp MJ, Dalm SU, de Jong M, Feelders RA, Hofland J, and Hofland LJ
- Subjects
- Epigenesis, Genetic, Humans, Somatostatin, Neuroendocrine Tumors genetics, Receptors, Somatostatin genetics, Receptors, Somatostatin metabolism
- Abstract
Both somatostatin (SST) and somatostatin receptors (SSTRs) are proteins with important functions in both physiological tissue and in tumors, particularly in neuroendocrine tumors (NETs). NETs are frequently characterized by high SSTRs expression levels. SST analogues (SSAs) that bind and activate SSTR have anti-proliferative and anti-secretory activity, thereby reducing both the growth as well as the hormonal symptoms of NETs. Moreover, the high expression levels of SSTR type-2 (SSTR2) in NETs is a powerful target for therapy with radiolabeled SSAs. Due to the important role of both SST and SSTRs, it is of great importance to elucidate the mechanisms involved in regulating their expression in NETs, as well as in other types of tumors. The field of epigenetics recently gained interest in NET research, highlighting the importance of this process in regulating the expression of gene and protein expression. In this review we will discuss the role of the epigenetic machinery in controlling the expression of both SSTRs and the neuropeptide SST. Particular attention will be given to the epigenetic regulation of these proteins in NETs, whereas the involvement of the epigenetic machinery in other types of cancer will be discussed as well. In addition, we will discuss the possibility to target enzymes involved in the epigenetic machinery to modify the expression of the SST-system, thereby possibly improving therapeutic options., (© 2020. The Author(s).)
- Published
- 2021
- Full Text
- View/download PDF
118. Homozygous TMEM127 mutations in 2 patients with bilateral pheochromocytomas.
- Author
-
Eijkelenkamp K, Olderode-Berends MJW, van der Luijt RB, Robledo M, van Dooren M, Feelders RA, de Vries J, Kerstens MN, Links TP, and van der Horst-Schrivers ANA
- Subjects
- Adrenal Gland Neoplasms pathology, Adult, Female, Genetic Testing, Germ-Line Mutation, Homozygote, Humans, Male, Middle Aged, Pheochromocytoma pathology, Adrenal Gland Neoplasms genetics, Genetic Predisposition to Disease, Membrane Proteins genetics, Pheochromocytoma genetics
- Abstract
Pheochromocytoma (PCC) and paraganglioma (PGL) are rare neuroendocrine tumors that are hereditary in up to 50% of patients. The gene encoding transmembrane-protein-127 (TMEM127) is one of the PCC/PGL-susceptibility genes with an autosomal dominant inheritance pattern. Here, we report 2 patients with bilateral PCC who both harbored a homozygous TMEM127-mutation. In a 31-year-old mentally retarded patient, the homozygous c.410-2A > G mutation was discovered during an update of DNA analysis. A 26-year-old mentally retarded patient was found to have a homozygous c.3G > A mutation. The parents of both patients were consanguineous. We reviewed previously reported clinical features of TMEM127 mutation carriers and compared our findings with case descriptions of homozygous mutations in other PGL/PCC-susceptibility genes. Homozygosity for an autosomal dominant inherited disorder is an extremely rare phenomenon and has, to our knowledge, not been reported before for the gene encoding TMEM127. In the present cases, the clinical picture does not seem to be very different from heterozygous TMEM127 mutation carriers, except for a relatively large tumor size and more pronounced plasma metanephrine concentration. It is unclear whether the mental retardation is causally related to homozygosity of the TMEM127 mutations. Updating genetic screening in patients in whom PCC/PGL has been diagnosed in the past should be considered as it might provide clinically relevant information., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
- Published
- 2018
- Full Text
- View/download PDF
119. A rare cause of dysregulated metabolic syndrome: cortisol-producing adrenocortical carcinoma.
- Author
-
Saes L, Boere IA, Hofland J, Mulder M, and Feelders RA
- Subjects
- Adrenal Cortex Neoplasms blood, Adrenal Cortex Neoplasms complications, Adrenocortical Carcinoma blood, Adrenocortical Carcinoma complications, Aged, Cushing Syndrome blood, Female, Humans, Hydrocortisone biosynthesis, Hydrocortisone blood, Metabolic Syndrome blood, Adrenal Cortex Neoplasms metabolism, Adrenocortical Carcinoma metabolism, Cushing Syndrome etiology, Metabolic Syndrome etiology
- Abstract
Adrenocortical carcinoma is a rare and highly malignant disease which can cause hypercortisolism leading to dysregulation of blood pressure and glucose levels. Most patients present with advanced disease. We describe the classic presentation of a functional adrenocortical carcinoma in a patient with metabolic syndrome.
- Published
- 2018
120. Recent developments in the diagnosis and therapy of well-differentiated neuroendocrine tumours.
- Author
-
Hofland J, Feelders RA, Brabander T, Franssen GJH, and de Herder WW
- Subjects
- Algorithms, Digestive System Neoplasms epidemiology, Digestive System Neoplasms physiopathology, Humans, Lung Neoplasms epidemiology, Lung Neoplasms physiopathology, Neoplasm Grading, Neuroendocrine Tumors epidemiology, Neuroendocrine Tumors physiopathology, Prognosis, Digestive System Neoplasms diagnosis, Digestive System Neoplasms therapy, Lung Neoplasms diagnosis, Lung Neoplasms therapy, Neuroendocrine Tumors diagnosis, Neuroendocrine Tumors therapy
- Abstract
Well-differentiated neuroendocrine tumours (NETs) of the digestive tract are being increasingly detected, which is partly explained by the increased use of endoscopic and cross-sectional imaging as well as improved recognition at histopathological evaluation. After the discovery of this relatively indolent type of epithelial malignancy over 100 years ago, their sporadic occurrence and divergent biological behaviour at multiple primary sites have hampered dedicated studies into NET pathogenesis and testing of drug efficacy in well-designed clinical trials. The last decade, however, has seen significant improvements in the NET field regarding our understanding of their pathophysiology. This has been substantiated by novel and exciting diagnostic and therapeutic options, including superior positron emission tomography imaging, treatment with unlabelled and radiolabelled somatostatin analogues and inhibitors of the mammalian target of rapamycin and vascular endothelial growth factor pathways. This review summarises contemporary studies within NET patients, which have enriched our clinical repertoire for this disease and have been instrumental in securing a remarkable improvement of overall survival within recent years.
- Published
- 2018
121. Future directions in the diagnosis and medical treatment of adrenocortical carcinoma.
- Author
-
Creemers SG, Hofland LJ, Korpershoek E, Franssen GJ, van Kemenade FJ, de Herder WW, and Feelders RA
- Subjects
- Adrenal Cortex Neoplasms epidemiology, Adrenalectomy methods, Adrenocortical Carcinoma epidemiology, Antineoplastic Agents, Hormonal administration & dosage, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Biomarkers, Tumor analysis, Chemotherapy, Adjuvant, Diagnostic Techniques, Endocrine trends, Humans, Mitotane administration & dosage, Radiotherapy, Adjuvant, Adrenal Cortex Neoplasms diagnosis, Adrenal Cortex Neoplasms therapy, Adrenocortical Carcinoma diagnosis, Adrenocortical Carcinoma therapy
- Abstract
Adrenocortical carcinoma (ACC) is a rare disease with a poor prognosis. Discrimination between ACCs and adrenocortical adenomas (ACAs) remains challenging, with the current gold standard being the Weiss score, consisting of several histopathological characteristics. However, new markers like Ki67, a marker for proliferation, and the staining of reticulins are promising not only as it comes to identifying malignancy but also as prognostic markers in patients with ACC. Currently, surgery is still the only curative treatment for ACC. Mitotane, an adrenolytic drug, is used in the adjuvant setting and in case of metastatic or advanced disease. Patients with progressive disease are frequently treated with mitotane, alone or in combination with etoposide, doxorubicine and cisplatin. Radiotherapy is indicated in selected cases. The low response rates and high toxicity of the systemic therapies emphasize the need for markers that enable the identification of responders and non-responders. Consequently, research is focusing on predictive factors varying from the expression of DNA repair genes to clinical patient characteristics. Subgroups of ACC with different prognosis have been identified based on transcriptome characteristics. As a conclusion from large molecular studies, ACCs appear to harbor many abnormalities compared to ACAs. Altered pathways driving ACC pathogenesis include the IGF, TP53 and the Wnt signaling pathway, allowing these as new potential targets for medical therapy. However, despite efforts in preclinical and clinical studies investigating efficacy of targeting these pathways, most novel therapies appear to be effective in only a subset of patients with ACC. New treatment concepts are therefore urgently needed., (© 2016 Society for Endocrinology.)
- Published
- 2016
- Full Text
- View/download PDF
122. Catecholamine-induced cardiomyopathy in a patient with malignant paraganglioma.
- Author
-
Heijneman JA, Boere IA, Feelders RA, de Herder WW, Kros JM, Manintveld OC, and Verduijn GM
- Subjects
- Adult, Bone Neoplasms secondary, Cardiomyopathies diagnostic imaging, Echocardiography, Humans, Liver Neoplasms secondary, Male, Paraganglioma metabolism, Retroperitoneal Neoplasms metabolism, Cardiomyopathies etiology, Catecholamines metabolism, Paraganglioma complications, Retroperitoneal Neoplasms complications
- Published
- 2015
123. Polymorphisms in the glucocorticoid receptor gene and in the glucocorticoid-induced transcript 1 gene are associated with disease activity and response to glucocorticoid bridging therapy in rheumatoid arthritis.
- Author
-
Quax RA, Koper JW, Huisman AM, Weel A, Hazes JM, Lamberts SW, and Feelders RA
- Subjects
- Adult, Aged, Arthritis, Rheumatoid drug therapy, Cohort Studies, Female, Glucocorticoids therapeutic use, Haplotypes, Humans, Male, Middle Aged, Severity of Illness Index, Treatment Outcome, Arthritis, Rheumatoid genetics, Receptors, Glucocorticoid genetics
- Abstract
Glucocorticoids (GC) are widely used in rheumatoid arthritis (RA). Ongoing active disease due to GC resistance may unfavorably influence long-term disease outcome in RA. We studied the association between the presence of glucocorticoid receptor (GR) and glucocorticoid-induced transcript 1 (GLCCI1) gene polymorphisms, which modulate GC sensitivity, and baseline disease activity score (DAS) and efficacy of GC bridging therapy in RA. We prospectively studied in vivo GC sensitivity in 138 patients with recent-onset or longstanding RA. In vivo GC sensitivity was expressed as the relative decrease in DAS following 2 weeks of standardized GC therapy. All patients were genotyped for the GR polymorphisms BclI (rs41423247), N363S (rs6195), 9β (rs6198), ER22/23EK (rs6189 + rs6190), and the GLCCI1 variant rs37972 and subsequently divided in groups carrying a polymorphism associated with increased GC sensitivity (BclI-G allele, N363S-G allele, GLCCI1-C allele) or decreased GC sensitivity (9β-G allele, ER22/23EK-A/A allele, GLCCI1-T allele). Differences in baseline DAS and relative decrease in DAS in the different genotype groups were analyzed using analysis of covariance and linear regression. Baseline DAS was higher in patients who carried polymorphisms of the GR and GLCCI1 genes associated with decreased GC sensitivity. GLCCI1 genotype, but not GR genotypes, was associated with improvement in DAS in male patients with RA. The GLCCI1 gene minor allele (rs37972) may be associated with less efficient GC bridging therapy in male RA patients. Carriers of the BclI-G, N363S-G, or GLCCI1-C alleles had lower levels of baseline disease activity, suggesting a role for the GLCCI1 and GR gene in regulation of GC sensitivity to endogenously produced cortisol.
- Published
- 2015
- Full Text
- View/download PDF
124. Comorbidities in Cushing's disease.
- Author
-
Sharma ST, Nieman LK, and Feelders RA
- Subjects
- ACTH-Secreting Pituitary Adenoma diagnosis, ACTH-Secreting Pituitary Adenoma mortality, ACTH-Secreting Pituitary Adenoma psychology, ACTH-Secreting Pituitary Adenoma therapy, Adenoma diagnosis, Adenoma mortality, Adenoma psychology, Adenoma therapy, Cause of Death, Comorbidity, Humans, Pituitary ACTH Hypersecretion diagnosis, Pituitary ACTH Hypersecretion mortality, Pituitary ACTH Hypersecretion psychology, Pituitary ACTH Hypersecretion therapy, Prognosis, Quality of Life, Risk Assessment, Risk Factors, Time Factors, ACTH-Secreting Pituitary Adenoma epidemiology, Adenoma epidemiology, Pituitary ACTH Hypersecretion epidemiology
- Abstract
Introduction: Cushing's disease is a rare disorder characterized by overproduction of ACTH from a pituitary adenoma leading to hypercortisolemia that in turn leads to increased morbidity and mortality., Methods: Here we review the comorbidities associated with Cushing's disease and their impact on quality of life and mortality., Results: Recent evidence suggests that correction of hypercortisolemia may not lead to complete resolution of comorbidities associated with this condition. In particular, increased cardiovascular risk may persist despite long-term remission of hypercortisolemia. This may be related to persistence of visceral adiposity, adverse adipokine profile, glucose intolerance, hypertension, dyslipidemia, atherosclerosis and a procoagulant phenotype. Prior prolonged exposure to glucocorticoids also may have irreversible effects on the central nervous system, leading to persistent cognitive and mood alterations. Osteoporosis and fractures, especially vertebral fractures, can further add to morbidity and a poor quality of life. Normalization of cortisol levels leads to significant improvement in comorbidities but long-term data regarding complete resolution are lacking and need further study., Conclusion: Early diagnosis and treatment of hypercortisolemia, aggressive management of comorbidities along with long-term follow-up is crucial for the optimal recovery of these patients.
- Published
- 2015
- Full Text
- View/download PDF
125. [When is a perioperative glucocorticoid stress-dose regime indicated?].
- Author
-
van Rossum EF and Feelders RA
- Subjects
- Dose-Response Relationship, Drug, Humans, Hyperglycemia chemically induced, Hyperglycemia complications, Adrenal Insufficiency prevention & control, Glucocorticoids administration & dosage, Glucocorticoids adverse effects, Hyperglycemia prevention & control, Perioperative Care methods
- Abstract
To avoid a life-threatening crisis due to adrenal insufficiency during or after surgery, extra glucocorticoids are often administered perioperatively to patients already taking them. However, this type of supplementation also has a downside, e.g. complications such as fluid retention, hyperglycaemia, psychiatric disturbances, infection and delayed wound healing. In patients with primary or central adrenal insufficiency their daily hydrocortisone substitution should be supplemented perioperatively depending on the type of surgery. Also, suppression of the pituitary-adrenal function may occur in patients being treated with exogenous glucocorticoids for other diseases and this may justify perioperative supplemental glucocorticoid administration. However, the extent of adrenal suppression in response to exogenous glucocorticoids is heterogeneous. This can be explained by differences in glucocorticoid type and dosage, treatment duration, mode of administration, as well as an individual's glucocorticoid sensitivity and metabolism of glucocorticoids. In this article we provide suggestions as to which patients should or should not be perioperatively supplemented with glucocorticoids.
- Published
- 2015
126. Pasireotide, a multi-somatostatin receptor ligand with potential efficacy for treatment of pituitary and neuroendocrine tumors.
- Author
-
Feelders RA, de Herder WW, Neggers SJ, van der Lely AJ, and Hofland LJ
- Subjects
- Acromegaly drug therapy, Humans, Ligands, Pituitary ACTH Hypersecretion drug therapy, Somatostatin adverse effects, Somatostatin therapeutic use, Neuroendocrine Tumors drug therapy, Pituitary Neoplasms drug therapy, Receptors, Somatostatin metabolism, Somatostatin analogs & derivatives
- Abstract
Somatostatin receptors are an important target for medical treatment of pituitary and neuroendocrine tumors. To date, five somatostatin receptor (sst) subtypes have been identified. The currently available somatostatin analogues octreotide and lanreotide have predominantly affinity for sst2. Pasireotide is a sst multireceptor ligand with affinity for sst1, sst2, sst3 and sst5 and this broader binding profile may translate into a higher efficacy with respect to suppression of hormone production and cell growth in certain tumors. Experimental animal studies and in vitro studies with cultured tumor cells have shown that pasireotide strongly suppresses growth hormone and adrenocorticotropin production. In addition, pasireotide can influence tumor cell growth via effects on apoptosis and angiogenesis. In this review, the role of somatostatin receptors in pituitary and neuroendocrine tumors is briefly discussed followed by an overview of possible applications of pasireotide based on recent trials in patients with acromegaly, Cushing's disease and neuroendocrine tumors., (Copyright 2013 Prous Science, S.A.U. or its licensors. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
127. 5-HIAA excretion is not associated with bone metabolism in carcinoid syndrome patients.
- Author
-
van Dijk SC, de Herder WW, Kwekkeboom DJ, Zillikens MC, Feelders RA, van Schaik RH, van Driel M, and van Leeuwen JP
- Subjects
- Aged, Alkaline Phosphatase metabolism, Biomarkers blood, Biomarkers metabolism, Biomarkers urine, Cell Differentiation drug effects, Cell Line, Female, Humans, Male, Malignant Carcinoid Syndrome blood, Middle Aged, Osteoblasts cytology, Osteoblasts drug effects, Osteoblasts metabolism, Serotonin blood, Serotonin pharmacology, Bone and Bones metabolism, Hydroxyindoleacetic Acid urine, Malignant Carcinoid Syndrome metabolism, Malignant Carcinoid Syndrome urine
- Abstract
In patients with a carcinoid syndrome and neuroendocrine tumors of the digestive tract (carcinoids), elevated circulating serotonin (5-hydroxytryptamine, 5-HT) levels can be demonstrated. It can be hypothesized that bone metabolism will be affected in these patients, since serotonin receptors are expressed on bone cells and serotonin effects on bone have been demonstrated. However, to date, no data are available on bone metabolism parameters in patients with neuroendocrine tumors of the digestive tract (carcinoids). In the current retrospective study we have measured serum bone formation markers P1CP (pro-collagen type I C-terminal), and osteocalcin, and the bone resorption marker NTx (collagen breakdown product N-terminal), in a group of 61 carcinoid patients with increased circulating serotonin levels as demonstrated by increased excretion of the serotonin breakdown product, 5-hydroxy indole acetic acid (5-HIAA), in the urine (>50 μmol/24 h, so-called "hyper-secretors") and a control group of 23 carcinoid patients, without increased 5-HIAA excretion (so-called non-secretors). The 24-h urinary excretion of 5-HIAA reflects the 24-h production of serotonin. Measurements of markers of bone metabolism were performed in serum samples obtained before the start of medical treatment. The hypersecretor group had on average a 10-fold higher urinary 5-HIAA excretion than the control (non-secretor) group. No significant differences in bone metabolism parameters could be demonstrated between hyper-secretors and controls (non-secretors). Correlation and regression analyses could not demonstrate significant age- and sex-adjusted correlations between urinary 5-HIAA excretion and any of the markers for bone turnover. A limitation is that the exposure time to elevated levels of serotonin is unknown, which might have been too short to induce effects on bone metabolism. Treatment of human pre-osteoblasts SV-HFO with serotonin didn't change alkaline phosphatase activity throughout differentiation as well as mineralization. In conclusion, the current study in a unique group of untreated carcinoid patients could not demonstrate a major role for circulating serotonin in the control of bone metabolism., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
128. Combined treatment for acromegaly with long-acting somatostatin analogs and pegvisomant: long-term safety for up to 4.5 years (median 2.2 years) of follow-up in 86 patients.
- Author
-
Neggers SJ, de Herder WW, Janssen JA, Feelders RA, and van der Lely AJ
- Subjects
- Adult, Aged, Aged, 80 and over, Diabetes Complications physiopathology, Drug Therapy, Combination, Electrocardiography, Female, Follow-Up Studies, Human Growth Hormone adverse effects, Human Growth Hormone therapeutic use, Humans, Liver Function Tests, Male, Middle Aged, Octreotide therapeutic use, Peptides, Cyclic therapeutic use, Somatostatin adverse effects, Young Adult, Acromegaly drug therapy, Human Growth Hormone analogs & derivatives, Receptors, Somatotropin antagonists & inhibitors, Somatostatin analogs & derivatives, Somatostatin therapeutic use
- Abstract
Background: We previously reported on the efficacy, safety, and quality of life (QoL) of long-acting somatostatin analogs (SSA) and (twice) weekly pegvisomant (PEG-V) in acromegaly and improvement after the addition of PEG-V to long-acting SSA., Objective: To assess the long-term safety in a larger group of acromegalic patients over a larger period of time: 29.2 (1.2-57.4) months (mean (range))., Design: Pegvisomant was added to SSA monotherapy in 86 subjects (37 females), to normalize serum IGF1 concentrations (n=63) or to increase the QoL. The median dosage was 60.0 (20-200) mg weekly., Results: After a mean treatment period of 29.2 months, 23 patients showed dose-independent PEG-V related transient liver enzyme elevations (TLEE). TLEE occurred only once during the continuation of combination therapy, but discontinuation and re-challenge induced a second episode of TLEE. Ten of these patients with TLEE also suffered from diabetes mellitus (DM). In our present series, DM had a 2.28 odds ratio (CI 1.16-9.22; p=0.03) higher risk for developing TLEE. During the combined therapy, a clinical significant decrease in tumor size by more than 20% was observed in 14 patients. Two of these patients were previously treated by pituitary surgery, 1 with additional radiotherapy and all other patients received primary medical treatment., Conclusion: Long-term combined treatment with SSA and twice weekly PEG-V up to more than 4 years seems to be safe. Patients with both acromegaly and DM have a 2.28 higher risk of developing TLEE. Clinical significant tumor shrinkage was observed in 14 patients during combined treatment.
- Published
- 2009
- Full Text
- View/download PDF
129. Differential regulation of human dopamine D2 and somatostatin receptor subtype expression by glucocorticoids in vitro.
- Author
-
de Bruin C, Feelders RA, Waaijers AM, van Koetsveld PM, Sprij-Mooij DM, Lamberts SW, and Hofland LJ
- Subjects
- Animals, Antineoplastic Agents, Hormonal metabolism, Cell Line, Cell Proliferation, DNA Fragmentation, Dexamethasone metabolism, Dopamine metabolism, Hormone Antagonists metabolism, Humans, Mifepristone metabolism, Octreotide metabolism, Protein Isoforms genetics, RNA, Messenger metabolism, Radioligand Assay, Receptors, Dopamine D2 genetics, Receptors, Somatostatin genetics, Somatostatin metabolism, Glucocorticoids metabolism, Protein Isoforms metabolism, Receptors, Dopamine D2 metabolism, Receptors, Somatostatin metabolism
- Abstract
Dopamine agonists (DA) and somatostatin (SS) analogues have been proposed in the treatment of ACTH-producing neuro-endocrine tumours that cause Cushing's syndrome. Inversely, glucocorticoids (GCs) can differentially influence DA receptor D(2) or SS receptor subtype (sst) expression in rodent models. If this also occurs in human neuro-endocrine cells, then cortisol-lowering therapy could directly affect the expression of these target receptors. In this study, we investigated the effects of the GC dexamethasone (DEX) on D(2) and sst expression in three human neuro-endocrine cell lines: BON (carcinoid) and TT (medullary thyroid carcinoma) versus DMS (small cell lung cancer), which is severely GC resistant. In BON and TT, sst(2) mRNA was strongly down-regulated in a dose-dependent manner (IC(50) 0.84 nM and 0.16 nM), whereas sst(5) and especially D(2) were much more resistant to DEX treatment. Sst(2) down-regulation was abrogated by a GC receptor antagonist and reversible in time upon GC withdrawal. At the protein level, DEX also induced a decrease in the total number of SS (-52%) and sst(2)-specific (-42%) binding sites. Pretreatment with DEX abrogated calcitonin inhibition by sst(2)-preferring analogue octreotide in TT. In DMS, DEX did not cause significant changes in the expression of these receptor subtypes. In conclusion, we show that GCs selectively down-regulate sst(2), but not D(2) and only to a minor degree sst(5) in human neuro-endocrine BON and TT cells. This mechanism may also be responsible for the low expression of sst(2) in corticotroph adenomas and underwrite the current interest in sst(5) and D(2) as possible therapeutic targets for a medical treatment of Cushing's disease.
- Published
- 2009
- Full Text
- View/download PDF
130. [Cushing's syndrome in children].
- Author
-
van Aken MO, Feelders RA, and de Herder WW
- Subjects
- Child, Cushing Syndrome urine, Diagnosis, Differential, Humans, Sensitivity and Specificity, Cushing Syndrome diagnosis, Dexamethasone, Hydrocortisone urine
- Published
- 2007
131. [Cushing's syndrome. II. New forms of treatment].
- Author
-
van Aken MO, Feelders RA, van der Lely AJ, Romijn JA, Lamberts SW, and de Herder WW
- Subjects
- ACTH-Secreting Pituitary Adenoma drug therapy, ACTH-Secreting Pituitary Adenoma surgery, Adenoma drug therapy, Adenoma surgery, Adrenalectomy, Adrenergic Antagonists therapeutic use, Cushing Syndrome drug therapy, Cushing Syndrome surgery, Humans, Pituitary Gland surgery, Treatment Outcome, ACTH-Secreting Pituitary Adenoma therapy, Adenoma therapy, Cushing Syndrome therapy
- Abstract
Several new therapeutic options both medicinal and surgical, have emerged for the treatment of Cushing's syndrome. In Cushing's disease caused by an adrenocorticotropin (ACTH) secreting pituitary adenoma, the introduction ofendoscopic pituitary surgery offers better visualization of the sella than does the traditional explorative surgery. However, at present it is unclear whether this will result in a better outcome. New drugs under investigation include universal somatostatin analogues such as SOM230, and a combination of a somatostatin analogue and dopamine agonist known as dopastatin. These agents may also be effective for the medicinal treatment of ectopic ACTH-secretion. Treatment with radioactive-labelled somatostatin-analogues such as 177lutetium octreotate is another option for these patients. The primary treatment for ACTH-independent Cushing's syndrome is laparoscopic adrenalectomy. In rare cases of bilateral adrenal hyperplasia, medicinal treatment aimed at new regulatory pathways of cortisol secretion can be applied.
- Published
- 2006
132. [Cushing's syndrome. I. New diagnostic developments].
- Author
-
van Aken MO, Feelders RA, de Jong FH, Pereira AM, Lamberts SW, and de Herder WW
- Subjects
- Corticotropin-Releasing Hormone, Dexamethasone, Diagnosis, Differential, Humans, Hydrocortisone analysis, Sensitivity and Specificity, 5-Hydroxytryptophan, Cushing Syndrome diagnosis, Magnetic Resonance Imaging methods, Positron-Emission Tomography methods
- Abstract
Over the past few years, new diagnostic tests for Cushing's syndrome have become available. Some of the other, older diagnostic tests have fallen into discredit as they could not distinguish conditions from one another sufficiently well. New biochemical tests include midnight salivary cortisol measurement and the combined dexamethasone-corticotropin releasing hormone (CRH) test. The high dose dexamethasone test and the CRH-stimulation test have been abandoned as they were unable to differentiate between hypophysial and ectopic secretion of adrenocorticotropic hormone (ACTH). For the detection of ectopic ACTH-secreting tumours new imaging techniques, such as somatostatin receptor scintigraphy and positron emission tomography with 5-hydroxytryptophan, have become available.
- Published
- 2006
133. Neuroendocrine tumors and somatostatin: imaging techniques.
- Author
-
de Herder WW, Kwekkeboom DJ, Valkema R, Feelders RA, van Aken MO, Lamberts SW, van der Lely AJ, and Krenning EP
- Subjects
- Carcinoid Tumor diagnostic imaging, Gastrointestinal Neoplasms diagnostic imaging, Humans, Indium Radioisotopes, Neuroendocrine Tumors chemistry, Paraganglioma diagnostic imaging, Pheochromocytoma diagnostic imaging, Pituitary Neoplasms diagnostic imaging, Radionuclide Imaging, Receptors, Somatostatin analysis, Neuroendocrine Tumors diagnostic imaging, Somatostatin analogs & derivatives
- Abstract
Tumors and metastases bearing the somatostatin receptor subtypes 2 (SSTR2) or SSTR5 can be visualized in vivo after injection of radiolabeled octapeptide somatostatin analogs like 111In-pentetreotide. The sensitivity of 111In-pentetreotide scintigraphy for the detection of carcinoid tumors is 86-95%. The sensitivity of 111In-pentetreotide scintigraphy for the detection of gastrinomas, vasoactive intestinal polypeptide-secreting tumors, and glucagonomas as well as clinically non-functioning lesions is 75-100%. However, for insulinoma this is 50-60%. 111In-pentetreotide scintigraphy generally has a lower detection rate for benign pheochromocytomas than 123I-MIBG scintigraphy, but it can have a complementary role for the staging of malignant pheochromocytomas. It can also be used for the detection of extra-adrenal pheochromocytomas and paragangliomas. Most GH- and TSH-secreting pituitary adenomas can be visualized using 111In-pentetreotide. 111In-pentetreotide scintigraphy is negative in microprolactinomas and ACTH-secreting pituitary microadenomas. 111In-pentetreotide scintigraphy has been successful for the localization of extra-pituitary ACTH-secreting tumors and their metastases, and especially for occult tumors. A large variety of lesions in and around the pituitary region express somatostatin receptors and, therefore, can be visualized by 111In-pentetreotide scintigraphy.
- Published
- 2005
134. [Posttraumatic hypopituitarism].
- Author
-
Alwani RA, Feelders RA, and Lamberts SW
- Subjects
- Accidents, Traffic, Adult, Amenorrhea etiology, Craniocerebral Trauma etiology, Female, Hematoma, Epidural, Cranial complications, Hematoma, Epidural, Cranial etiology, Humans, Hypopituitarism complications, Hypopituitarism etiology, Pituitary Function Tests, Pituitary Gland, Anterior injuries, Weight Gain, Craniocerebral Trauma complications, Hypopituitarism diagnosis
- Abstract
A 39-year-old woman was admitted with complaints of weight gain, a decreased sense of well-being and amenorrhoea. One and a half year prior to admission she had been involved in a serious road accident and had spent several days in coma due to an epidural haematoma. She was found to have hypopituitarism with deficient somatotropic and gonadotropic axes, as well as mild hyperprolactinaemia, probably due to a pituitary stalk lesion. All patients with severe trauma to the skull are at risk of developing posttraumatic hypopituitarism, so that pituitary function testing should be performed routinely, certainly in the presence of symptoms.
- Published
- 2004
135. ['Hungry bone' syndrome, characterized by prolonged symptomatic hypocalcemia, as a complication of the treatment for hyperthyroidism].
- Author
-
de Ronde W, ten Have SM, van Daele PL, Feelders RA, and van der Lely AJ
- Subjects
- Adult, Calcium pharmacokinetics, Female, Humans, Hyperthyroidism surgery, Hypocalcemia etiology, Hypoparathyroidism etiology, Time Factors, Calcium administration & dosage, Hyperthyroidism complications, Hypocalcemia drug therapy, Thyroidectomy adverse effects
- Abstract
A 22-year-old woman presented with palpitations, agitation, heat intolerance and unintentional weight loss that had started several months before. Pharmacotherapy for hyperthyroidism was prescribed, but a year later thyroidectomy was performed in connection with a lack of treatment compliance. A few hours after the operation the patient developed a tingling sensation and muscle cramp, which were found to be due to severe hypocalcaemia. Although surgery was complicated by hypoparathyroidism, there was an unusually high need for calcium combined with a low calcium excretion in the urine. Such a high need for calcium due to the increased bone reconstruction induced by the hyperthyroidism is referred to as the hungry bone syndrome. One should be particularly alert to this complication in cases of severe, prolonged hyperthyroidism, certainly in the presence of existing or peroperatively induced damage to the parathyroids. In this patient, calcium suppletion led to normalisation of the serum calcium level two weeks postoperatively; she was discharged from the hospital in good condition after 3 weeks.
- Published
- 2004
136. [Acromegaly. Treatment of the causal factor and the oral sequelae].
- Author
-
Feelders RA, Delwel EJ, and de Baat C
- Subjects
- Acromegaly pathology, Adenoma surgery, Glucose Tolerance Test, Humans, Lip pathology, Male, Middle Aged, Mouth pathology, Pituitary Neoplasms surgery, Tooth Extraction, Treatment Outcome, Acromegaly diagnosis, Adenoma diagnosis, Growth Hormone blood, Pituitary Neoplasms diagnosis
- Abstract
During the last few years, a 64-years-old man experienced a progressive enlargement of his hands, feet, and tongue and an alteration in the position of his frontal teeth. In a university medical clinic acromegaly was diagnosed, based on external features, serum tests, and an oral glucose tolerance test. A pituitary microadenoma was discovered. The most common oral features of acromegaly are a prognatic mandible, interdental spaces, macroglossy, and everted, swollen lips. In this article the primary treatment and the possible oral sequelae are described.
- Published
- 2004
137. [Irreversible coma following hypoglycemia in Sheehan syndrome with adrenocortical insufficiency].
- Author
-
Sas AM, Meynaar IA, Laven JS, Bakker SL, and Feelders RA
- Subjects
- Adrenal Insufficiency drug therapy, Adult, Blood Glucose metabolism, Fatal Outcome, Female, Glucocorticoids therapeutic use, Humans, Hypoglycemia drug therapy, Hypopituitarism drug therapy, Hysterectomy, Postpartum Hemorrhage complications, Postpartum Hemorrhage etiology, Prednisone therapeutic use, Pregnancy, Shock etiology, Shock surgery, Adrenal Insufficiency complications, Coma etiology, Hypoglycemia complications, Hypopituitarism complications, Postpartum Hemorrhage surgery
- Abstract
A 24-year-old woman of Somali origin delivered at term after an uncomplicated pregnancy. Post-partum haemorrhage resulted in hypovolaemic shock which was treated by hysterectomy. Five days later she became comatose due to unrecognised hypoglycaemia which caused severe irreversible brain damage and status epilepticus. Treatment in the intensive care unit with artificial respiration, prednisolone, desmopressin, inotropic support, barbiturates and an anaesthetic under EEG guidance was unsuccessful. The patient died 28 days post-partum. The hypoglycaemia was due to a combination of (a) inadequate glucose intake and (b) lack of counter-regulatory mechanisms due to a deficiency of steroids and growth hormone as a result of loss of pituitary function (Sheehan syndrome) together with adrenocortical insufficiency. The combination of Sheehan syndrome and primary adrenocortical insufficiency has not been described previously in the literature.
- Published
- 2003
138. Characteristics of recovery from the euthyroid sick syndrome induced by tumor necrosis factor alpha in cancer patients.
- Author
-
Feelders RA, Swaak AJ, Romijn JA, Eggermont AM, Tielens ET, Vreugdenhil G, Endert E, van Eijk HG, and Berghout A
- Subjects
- Aged, Aged, 80 and over, Antineoplastic Agents, Alkylating therapeutic use, Cytokines blood, Euthyroid Sick Syndromes etiology, Female, Humans, Hydrocortisone blood, Male, Melphalan therapeutic use, Middle Aged, Perfusion, Recombinant Proteins therapeutic use, Thyroid Hormones blood, Thyrotropin blood, Thyroxine-Binding Proteins metabolism, Time Factors, Euthyroid Sick Syndromes drug therapy, Melanoma complications, Sarcoma complications, Soft Tissue Neoplasms complications, Tumor Necrosis Factor-alpha therapeutic use
- Abstract
Cytokines have been implicated in the pathogenesis of the euthyroid sick syndrome. Isolated limb perfusion (ILP) with recombinant human tumor necrosis factor alpha (rTNF) and melphalan in patients with melanoma or sarcoma is accompanied by high systemic TNF levels. We examined the prolonged effects (7 days) of ILP on thyroid hormone metabolism with respect to induction and recovery of the euthyroid sick syndrome in six cancer patients. After ILP, when the limb is reconnected to the systemic circulation, leakage of residual rTNF resulted in systemic peak levels at 10 minutes postperfusion followed by a parallel increase in plasma interleukin-6 (IL-6) and cortisol, with maximum levels at 4 hours (P < .05). A rapid decrease was observed at 5 minutes for plasma triiodothyronine (T3), reverse T3 (rT3), thyroxine (T4), and thyroxine-binding globulin (TBG) (P < .05), whereas free T4 (FT4) and T3-uptake showed a sharp increase, with peak levels at 5 minutes (P < .05). T3, T4, and TBG levels remained low until 24 hours after ILP In contrast, rT3 increased above pretreatment values to maximum levels at 24 hours (P < .05). Plasma thyrotropin (TSH) showed an initial decrease at 4 hours postperfusion (P < .05) but exceeded pretreatment values from day 1 to day 7 (by +94%+/-43% to +155%+/-66%, P < .05), preceding the recovery of T4 and T3 levels. T3 and rT3 returned to initial values at day 4. T4 and TBG levels recovered at day 2. T4 exceeded basal values at days 5 to 7 (P < .05). It is concluded that ILP with rTNF induces a euthyroid sick syndrome either directly or indirectly through other mediators such as IL-6 or cortisol. The recovery from this euthyroid sick syndrome is, at least in part, TSH-dependent, since the prolonged elevation of TSH values preceded and persisted during the normalization of T3 and the elevation of T4 levels. This biphasic pattern of induction of and recovery from the euthyroid sick syndrome may be a general feature of nonthyroidal disease. The euthyroid sick syndrome should be interpreted not only in relation to the presence of nonthyroidal diseases but also in relation to the recovery from these diseases.
- Published
- 1999
- Full Text
- View/download PDF
139. Structure, function and clinical significance of transferrin receptors.
- Author
-
Feelders RA, Kuiper-Kramer EP, and van Eijk HG
- Subjects
- Female, Humans, Infant, Newborn, Pregnancy, Protein Conformation, Receptors, Transferrin blood, Receptors, Transferrin chemistry, Receptors, Transferrin metabolism
- Abstract
Iron plays an essential role in a spectrum of metabolic processes. Cellular iron uptake is facilitated by transferrin receptor (TfR)-mediated endocytosis. In recent years more insight has been obtained in TfR physiology and the regulation of cellular iron homeostasis. The synthesis of TfR and the iron storage protein ferritin is regulated reciprocally at the post-transcriptional level according to the cellular iron status. As a result of externalization of TfR during the endocytic cycle, a soluble form of TfR can be detected in serum. The serum TfR (sTfR) level is closely related to erythroid TfR turnover and the prime determinants of the sTfR concentration are cellular iron demands and erythroid proliferation rate. In the absence of a hyperplastic erythropoiesis the sTfR level is a sensitive parameter of early tissue iron deficiency. The entire spectrum of body iron status can be assessed by measurement of serum ferritin and sTfR levels, with ferritin as marker of tissue iron stores and sTfR as index of tissue iron needs. The sTfR may be a promising tool to detect iron deficiency in inflammatory states and in the anaemia of chronic disease as its concentration is, in contrast to ferritin levels, not influenced by the acute phase response. Determination of sTfR levels may also improve assessment of body iron stores during pregnancy and in neonates. Finally, the sTfR may be a useful parameter to monitor erythropoiesis in various clinical settings, for instance in the prediction of the haematological response to erythropoietin treatment. However, standardization of the sTfR assay, with definition of reference and pathological ranges, is necessary for the definitive introduction of the sTfR as major parameter of iron metabolism.
- Published
- 1999
- Full Text
- View/download PDF
140. Regulation of iron metabolism in the acute-phase response: interferon gamma and tumour necrosis factor alpha induce hypoferraemia, ferritin production and a decrease in circulating transferrin receptors in cancer patients.
- Author
-
Feelders RA, Vreugdenhil G, Eggermont AM, Kuiper-Kramer PA, van Eijk HG, and Swaak AJ
- Subjects
- Acute-Phase Proteins drug effects, Adult, Aged, Anemia blood, Anemia etiology, C-Reactive Protein metabolism, Chemotherapy, Cancer, Regional Perfusion, Female, Ferritins blood, Humans, Interferon-gamma administration & dosage, Interleukin-6 blood, Iron blood, Male, Melanoma complications, Melanoma pathology, Melanoma therapy, Melphalan therapeutic use, Middle Aged, Neoplasm Metastasis, Orosomucoid metabolism, Recombinant Proteins administration & dosage, Recombinant Proteins therapeutic use, Sarcoma complications, Sarcoma therapy, Serum Albumin metabolism, Time Factors, Transferrin metabolism, Tumor Necrosis Factor-alpha administration & dosage, Tumor Necrosis Factor-alpha metabolism, alpha 1-Antitrypsin metabolism, Acute-Phase Proteins metabolism, Anemia therapy, Ferritins biosynthesis, Interferon-gamma therapeutic use, Iron metabolism, Melanoma blood, Receptors, Transferrin blood, Sarcoma blood, Tumor Necrosis Factor-alpha therapeutic use
- Abstract
Background: The acute-phase response and anaemia of chronic disease are characterized by hypoferraemia associated with an increased ferritin synthesis, which might be mediated by the activated cytokine cascade., Methods: We examined the prolonged effects of isolated limb perfusion (ILP) with recombinant human tumour necrosis factor alpha (rTNF), recombinant human interferon gamma (rIFN-gamma) and melphalan on interleukin (IL) 6 and acute-phase protein levels, iron status and serum transferrin receptor (sTfR) levels in 12 patients with melanoma or sarcoma. Patients were treated with ILP during 90 min after pretreatment with rIFN-gamma during 2 days., Results: After ILP, leakage of TNF resulted in systemic peak levels at 3 min followed by an increase in IL-6 with maximum levels at 4h. C-reactive protein (CRP) rose at 4 h to peak levels at day 2, whereas alpha 1-antitrypsin and alpha 1-acid glycoprotein increased to maximum levels at day 3. Albumin and transferrin levels decreased after ILP and recovered after day 2. Serum iron and sTfR levels decreased during pretreatment and after ILP to minimum levels at 8 h and day 1 respectively. This was associated with an increase in serum ferritin levels, which paralleled CRP values., Conclusions: Our data point to a central role for the cytokine network in the modulation of iron metabolism in the acute-phase response and anaemia of chronic disease. TNF, possibly via induction of IL-6, and IFN-gamma induce hypoferraemia, which may in part result from a decrease in tissue iron release based on a primary stimulation of ferritin synthesis. The fall in sTfR levels may reflect an impaired erythroid growth and/or TfR expression mediated by TNF and IFN-gamma.
- Published
- 1998
- Full Text
- View/download PDF
141. Serum transferrin receptor levels in anaemia of rheumatoid arthritis and effects of iron chelation treatment.
- Author
-
Feelders RA, Vreugdenhil G, Manger B, van Eijk HG, and Swaak AJ
- Subjects
- Anemia complications, Anemia diagnosis, Anemia, Hypochromic diagnosis, Arthritis, Rheumatoid complications, Female, Humans, Iron Chelating Agents pharmacology, Male, Anemia blood, Arthritis, Rheumatoid blood, Iron metabolism, Receptors, Transferrin metabolism
- Published
- 1994
- Full Text
- View/download PDF
142. Iron chelators may enhance erythropoiesis by increasing iron delivery to haematopoietic tissue and erythropoietin response in iron-loading anaemia.
- Author
-
Vreugdenhil G, Smeets M, Feelders RA, and van Eijk HG
- Subjects
- Anemia metabolism, Bone Marrow drug effects, Bone Marrow metabolism, Drug Evaluation, Erythropoietin therapeutic use, Hematopoietic System metabolism, Humans, Recombinant Proteins therapeutic use, Anemia drug therapy, Chelation Therapy, Erythropoiesis drug effects, Erythropoietin metabolism, Hematopoietic System drug effects, Iron metabolism, Iron Chelating Agents therapeutic use
- Abstract
Based on the mode of action of iron chelators, one might expect a decrease in bone marrow iron availability, resulting in worsening of the anaemia in certain types of iron-loading anaemia. However, improvement of anaemia or reduction in transfusion requirements during chelation treatment has been reported in various types of iron-loading anaemia. It is suggested that iron chelators act as mediators facilitating iron release from storage sites and its delivery to haematopoietic tissues. In addition, a reduction of iron stores may upregulate erythropoietin response and bring about a decrease of disease activity in inflammatory disorders, resulting in a haemoglobin rise. Large trials with (oral) iron chelators are required to verify these possible effects.
- Published
- 1993
- Full Text
- View/download PDF
143. Adaptation of transferrin protein and glycan synthesis.
- Author
-
de Jong G, van Noort WL, Feelders RA, de Jeu-Jaspars CM, and van Eijk HG
- Subjects
- Adult, Anemia, Hypochromic metabolism, Arthritis, Rheumatoid metabolism, Contraceptives, Oral adverse effects, Female, Humans, Hydrogen-Ion Concentration, Immunoelectrophoresis, Two-Dimensional, Iron metabolism, Isoelectric Focusing, Male, Polysaccharides immunology, Pregnancy, Transferrin chemistry, Transferrin immunology, Polysaccharides biosynthesis, Transferrin biosynthesis
- Abstract
We report the patterns of variability in transferrin structure in pregnancy, iron deficiency anemia, women using oral contraceptives, nonanaemic rheumatoid arthritis, iron deficient rheumatoid arthritis and anemia of the chronic diseases. Changes in microheterogeneity were assessed by crossed immuno isoelectric focusing of serum transferrin. Intra-individual variation in the control group was minimal. Equally, inter-individual variation in controls and groups with established stable disease was very limited. In pregnancy an increase in transferrin concentration was accompanied by redirection of glycan synthesis to the highly sialylated and highly branched glycans, an effect also shown in women using oral contraceptives. Iron deficiency anemia was accompanied by increased protein core synthesis without the large shifts in the microheterogeneity pattern as seen in pregnancy at similar transferrin concentration. In contrast to this, rheumatoid arthritis was accompanied by decreased protein synthesis while the microheterogeneity pattern shifted significantly towards the highly branched glycans. Interpreted in the respective pathophysiological contexts results show that: (1) N-linked glycosylation of transferrin is a strictly controlled process, both in the physiological states and in disease. (2) Microheterogeneity is determined independently from transferrin protein synthetic rate. (3) Provisionally observed changes in the glycosylation can modulate the biological activity of the glycoprotein and as a result redirect internal iron fluxes. This proposition can be applied to altered iron metabolism in both pregnancy, oral contraceptives and rheumatoid arthritis. Changes are not operative in iron deficiency because qualitatively iron metabolism is not altered in this state.
- Published
- 1992
- Full Text
- View/download PDF
144. Possible mechanisms underlying potentiating effects of iron chelators in hematopoietic response to erythropoietin.
- Author
-
Vreugdenhil G, Feelders RA, Coppens PJ, and de Leeuw PW
- Subjects
- Anemia drug therapy, Anemia etiology, Drug Synergism, Humans, Kidney Failure, Chronic complications, Deferoxamine administration & dosage, Erythropoietin administration & dosage, Hematopoiesis drug effects
- Published
- 1992
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.