Marcello Filopanti

MEN1-related hyperparathyroidism: response to cinacalcet and its relationship with the calcium-sensing receptor gene variant Arg990Gly

OBJECTIVEnPrimary hyperparathyroidism (PHPT) is a challenging problem in type 1 multiple endocrine neoplasia (MEN1) due to the high postsurgery recurrence rate. The aim was to evaluate the efficacy of cinacalcet in MEN1 patients in comparison with patients with sporadic PHPT (sPHPT) and the effect of Arg990Gly calcium-sensing receptor (CASR) polymorphism on the response to treatment.nnnDESIGNnThis is a randomized, crossover, double-blind study carried out in the University Hospitals.nnnMETHODSnFifteen MEN1 patients with PHPT were randomized to two groups, one administered with 30 mg daily cinacalcet, titrated until calcium normalization, and one with placebo. After 3 months, patients were reassessed and after washout switched to the other treatment. For comparison, 20 sPHPT patients with similar calcium levels were administered with cinacalcet for 3 months. Ionized and total calcium, phosphate, and parathyroid hormone (PTH) were evaluated. CASR Arg990Gly was genotyped on blood DNA by direct sequencing.nnnRESULTSnCinacalcet normalized calcium, increased phosphate, and reduced PTH levels in all patients. Cinacalcet dosage required to normalize calcium in MEN1 and sPHPT was not significantly different (45±21 vs 54±25 mg/day). Few mild adverse events, not requiring drug withdrawal, were observed in both the groups. No association between Arg990Gly CASR polymorphism and response to cinacalcet was found.nnnCONCLUSIONSnThis short-term prospective study demonstrated that the efficacy profile of cinacalcet in patients with MEN1-related PHPT and in those with sPHPT was similar and was not influenced by the 990 CASR variant. Although long-term safety and efficacy data are required, cinacalcet might be considered a treatment option in MEN1 patients who have contraindications to surgery or persistent PHPT after surgery.

Quantitative Analysis of Methylation Defects and Correlation With Clinical Characteristics in Patients With Pseudohypoparathyroidism Type I and GNAS Epigenetic Alterations

CONTEXTnPseudohypoparathyroidism type I (PHP-I) includes two main subtypes, PHP-Ia and -Ib. About 70% of PHP-Ia patients, who show Albright hereditary osteodystrophy (AHO) associated with resistance toward multiple hormones (PTH/TSH/GHRH/gonadotropins), carry heterozygous mutations in the α-subunit of the stimulatory G protein (Gsα) exons 1-13, encoded by the guanine nucleotide binding-protein α-stimulating activity polypeptide 1 (GNAS), whereas the majority of PHP-Ib patients, who classically display hormone resistance limited to PTH and TSH with no AHO sign, have methylation defects in the imprinted GNAS cluster. Recently methylation defects have been detected also in patients with PHP and different degrees of AHO, indicating a molecular overlap between the two forms.nnnOBJECTIVESnThe objectives of the study were to collect patients with the following characteristics: clinical PHP-I (with or without AHO), no mutation in Gsα coding sequence, but the presence of GNAS methylation alterations and to investigate the existence of correlations between the degree of the epigenetic defect and the severity of the disease.nnnPATIENTS AND METHODSnWe quantified GNAS methylation alterations by both PCR-pyrosequencing and methylation specific-multiplex ligation-dependent probe amplification assay in genomic DNA from 63 patients with PHP-I and correlated these findings with clinical parameters (age at diagnosis; calcium, phosphorus, PTH, TSH levels; presence or absence of each AHO sign).nnnRESULTSnBy both approaches, the degree of the imprinting defect did not correlate with the onset of the disease, the severity of endocrine resistances, or with the presence/absence of specific AHO signs.nnnCONCLUSIONSnSimilar molecular alterations may lead to a broad spectrum of diseases, from isolated PTH resistance to complete PHP-Ia, and the degree of methylation alterations does not reflect or anticipate the severity and the type of different PHP/AHO manifestations.

Dopamine D2 receptor gene polymorphisms and response to cabergoline therapy in patients with prolactin-secreting pituitary adenomas.

Dopamine-agonist cabergoline (CB) reduces prolactin (PRL) secretion and tumor size in 80% of patients with prolactin-secreting adenomas (PRL-omas) by binding type 2 dopamine receptor (DRD2). The mechanisms responsible for resistance to CB remain largely unknown. To assess the association of DRD2 with sensitivity to CB, TaqI-A1/A2, TaqI-B1/B2, HphI-G/T and NcoI-C/T genotypes were determined in a cross-sectional retrospective study, including 203 patients with PRL-oma. DRD2 alleles frequencies did not differ between patients and 212 healthy subjects. Conversely, NcoI-T allele frequency was higher in resistant rather than responsive patients, considering both PRL normalization (56.6 vs 45.3%, P=0.038) and tumor shrinkage (70.4 vs 41.4%, P=0.006). Finally, [TaqI A1−/TaqI B1−/HphI T−/NcoI T−] haplotype was found in 34.5% of patients normalizing PRL with ⩽3u2009mg/week of CB vs 11.3% of resistants (P=0.021). In conclusion, resistance to CB was associated with DRD2 NcoI-T+ allele, consistent with evidence suggesting that this variant may lead to reduction and instability of DRD2 mRNA or protein.

Influence of the d3GH receptor polymorphism on the metabolic and biochemical phenotype of GH-deficient adults at baseline and during short- and long-term recombinant human GH replacement therapy

OBJECTIVEnA common polymorphic variant of GH receptor (exon 3 deletion, d3GHR) has been linked with increased response to recombinant human GH (rhGH) in some patients with or without GH deficiency (GHD). The aim of the study was to investigate the impact of the GHR genotype on the phenotype of GHD adults and on the metabolic effect of rhGH therapy.nnnDESIGNnProspective study of GHD patients evaluated before and during short- (1 year, n=100) and long-term (5 years, n=50) rhGH therapy.nnnMETHODSnEffects of rhGH on IGF1 levels, body composition (body fat percentage, BF%), body mass index, lipid profile, and glucose homeostasis (fasting insulin and glucose, insulin sensitivity indexes) were evaluated according to the presence or the absence of the d3GHR variant.nnnRESULTSnThe different genotype did not influence basal phenotype of GHD. Short-term rhGH determined normalization of IGF1 levels, decrease in BF%, and worsening of insulin sensitivity, independently from the presence of the d3GHR allele. A significant increase in high-density lipoprotein cholesterol occurred in the d3GHR group. Normalization of IGF1 levels and decrease in BF% were maintained after 5 years. Insulin sensitivity restored to basal values, though in d3GHR patients fasting glucose remained significantly higher than at baseline. After both 1 and 5 years, percentage of subjects with impaired glucose tolerance, similar in the two groups at baseline, decreased in fl/fl while doubled in d3GHR patients. In this last group, a long-term significant reduction in total and low-density lipoprotein cholesterol was also observed.nnnCONCLUSIONnThe functional difference of d3GHR may influence some metabolic effects of rhGH on GHD adults.

Analysis of genetic variants of phosphodiesterase 11A in acromegalic patients

OBJECTIVESnAberrant cAMP signaling is involved in the pathogenesis of somatotropinomas. The aim of the study was to screen acromegalic patients for the presence of variants of phosphodiesterase type 11A (PDE11A) gene, which have been recently identified in adrenocortical and testicular tumors.nnnSUBJECTS AND METHODSnWe sequenced the PDE11A gene-coding region in 78 acromegalic patients and 110 controls. Immunohistochemistry for PDE11A was performed in a subgroup of adenomas and normal pituitary samples.nnnRESULTSnWe found 15 nonsynonymous germline substitutions in 13 acromegalic patients (17%), i.e. 14 missense variants (Y727C in six, R804H in one, R867G in four, and M878V in three) and one truncating mutation (FS41X), with a prevalence only slightly higher than that observed in controls (14%). Immunohistochemistry revealed PDE11A expression higher in somatotropinomas than in normal somatotrophs, without significant difference between tumors with or without PDE11A variants, with the exception of two tumors (one with loss of heterozygosity (LOH) at the PDE11A locus and one with FS41X mutation) showing markedly reduced PDE11A staining. No significant differences in hormonal and clinical parameters between patients with or without PDE11A variants were observed, although patients with PDE11A changes showed a tendency to have a more aggressive tumor compared with patients with wild-type sequence (extrasellar extension in 69 vs 45%).nnnCONCLUSIONSnThis study first demonstrated the presence of PDE11A variants in a subset of acromegalic patients, which was only slightly more frequent than in controls. The normal expression of the enzyme in the majority of tumor tissues together with the lack of significant clinical phenotype suggests that these variants might only marginally contribute to the development of somatotropinomas.

Role of UGT1A1 and ADH gene polymorphisms in pegvisomant-induced liver toxicity in acromegalic patients.

CONTEXTnHepatotoxicity is one of the most serious adverse effects in acromegalic patients treated with pegvisomant (PEG-V). Recent studies have found an association between this adverse event and the UGT1A1 allele 28 polymorphism associated with Gilberts syndrome.nnnOBJECTIVEnTo determine whether UGT1A1*28 and alcohol dehydrogenase (ADH) polymorphisms influence liver toxicity during PEG-V treatment.nnnDESIGN AND SETTINGnMulticenter observational retrospective study conducted in 13 tertiary care endocrinology units in Italy.nnnPATIENTSnA total of 112 patients with active disease resistant to somatostatin analogs (SSTa) and 108 controls were enrolled.nnnINTERVENTIONSnClinical and biochemical data were recorded by electronic clinical reporting forms. Blood or DNA samples were sent to the coordinating center for genotyping.nnnRESULTSnNo differences in genotypes between patients and controls were found. During PEG-V therapy liver function tests (LFT), abnormalities and overt hepatotoxicity developed in 17 and 4.5% of patients respectively. Logistic and linear regression analyses showed an association between LFT abnormalities during the follow-up visit and prior events of LFT abnormalities in medical history (odds ratio=1.25; P=0.04) and the number of concomitant medications, other than SSTa (B=3.9; P=0.03). No correlation between LFT alterations and UGT1A1 allele 28 as well as ADH1C and B polymorphisms was found.nnnCONCLUSIONSnUGT1A1 allele 28 and ADH1C and B polymorphisms do not predict increased risk of hepatotoxicity during PEG-V therapy. Conversely, patients with multi-therapies and with previous episodes of liver disease should be carefully managed, due to the observed association between these conditions and LFT abnormalities during PEG-V therapy.

Hypothalamic-Pituitary Axis in Non-Functioning Pituitary Adenomas: Focus on the Prevalence of Isolated Central Hypoadrenalism

Introduction: Non-functioning pituitary adenomas (NFPA) account for about 40% of pituitary tumors. Pituitary deficiencies are present at diagnosis in 60-80% of NFPA, and, classically, growth hormone (GH) secretion is lost first, while adrenocorticotropic hormone is expected to disappear last. The aim of this study was to evaluate the incidence of multiple or isolated pituitary deficiencies in a large series of NFPA. Materials and Methods: We retrospectively analyzed data on 218 NFPA cases (59% females, 59% with macroadenomas, average age: 50.2 ± 17 years) followed up at our center from 1990 to 2013. At diagnosis all patients had a complete evaluation of pituitary function in basal conditions and provocative tests for the hypothalamic-pituitary-adrenal axis, while tests for GH deficiency (GHD) were carried out in 38%. Results: 52.3% of patients (65.6% of macroadenomas, 33.3% of microadenomas) presented at least 1 pituitary deficiency: isolated deficiency in 29.8%, multiple deficiencies in 30% and panhypopituitarism in 9%. Isolated deficiencies were hypogonadism in 11.5% of patients (8% in micro-, 14% in macroadenomas), hypoadrenalism in 10.1% (14% in micro-, 7% in macroadenomas) and GHD in 8.3% (8.9% in micro-, 7.8% in macroadenomas). About 30% of microadenomas had at least 1 pituitary deficiency at diagnosis, independently of tumor localization within the sellar region. Conclusions: The presence of isolated hypoadrenalism suggests that the order of appearance of hypopituitarism does not always follow the one expected. Given the relatively high prevalence of isolated hypoadrenalism even in microadenomas, we suggest a full assessment of basal and dynamic pituitary function in all NFPA regardless of tumor size.

Growth hormone-releasing hormone-producing pancreatic neuroendocrine tumor in a multiple endocrine neoplasia type 1 family with an uncommon phenotype.

The objective of this study was to describe a multiple endocrine neoplasia type 1 (MEN1) family characterized by primary hyperparathyroidism, in association with acromegaly because of ectopic growth hormone-releasing hormone (GHRH) secretion by a pancreatic neuroendocrine tumor in a young man and with a bronchial carcinoid in his mother. We investigate the clinical, radiological imaging, histopathologic findings, and therapy. An 18-year-old man successfully underwent subtotal parathyroidectomy for primary hyperparathyroidism. A subsequent genetic analysis showed a MEN1 gene mutation. Three years later, acromegaly because of ectopic GHRH secretion was diagnosed (pituitary MRI negative and elevated GHRH levels). A search for an ectopic tumor was unsuccessful and somatostatin analog therapy was started. Successively, scintigraphy with somatostatin analogs (68-Ga-DOTATOC-PET) showed three focal areas in the pancreatic tail. Distal pancreatectomy showed multiple pancreatic neuroendocrine tumors and hormonal status was normalized. Afterwards, the evaluation of the patient’s mother, carrying the same mutation, indicated a primary hyperparathyroidism and a 4 cm lung mass. The patient underwent subtotal pneumonectomy and the histological analysis was consistent with the diagnosis of a typical bronchial carcinoid. In conclusion, an atypical phenotype may be recorded in MEN1 families, thus emphasizing the importance of the new imaging and surgical techniques in the diagnosis and treatment of such a rare disease.

Reevaluation of Acromegalic Patients in Long-Term Remission according to Newly Proposed Consensus Criteria for Control of Disease.

Acromegaly guidelines updated in 2010 revisited criteria of disease control: if applied, it is likely that a percentage of patients previously considered as cured might present postglucose GH nadir levels not adequately suppressed, with potential implications on management. This study explored GH secretion, as well as hormonal, clinical, neuroradiological, metabolic, and comorbid profile in a cohort of 40 acromegalic patients considered cured on the basis of the previous guidelines after a mean follow-up period of 17.2 years from remission, in order to assess the impact of the current criteria. At the last follow-up visit, in the presence of normal IGF-I concentrations, postglucose GH nadir was over 0.4u2009μg/L in 11 patients (Group A) and below 0.4u2009μg/L in 29 patients (Group B); moreover, Group A showed higher basal GH levels than Group B, whereas a significant decline of both GH and postglucose GH nadir levels during the follow-up was observed in Group B only. No differences in other evaluated parameters were found. These results seem to suggest that acromegalic patients considered cured on the basis of previous guidelines do not need a more intensive monitoring than patients who met the current criteria of disease control, supporting instead that the cut-off of 0.4 mcg/L might be too low for the currently used GH assay.

Hypercalciuria May Persist After Successful Parathyroid Surgery and It Is Associated With Parathyroid Hyperplasia.

CONTEXTnHypercalciuria is frequently found in primary hyperparathyroidism (1HPT) and, although it generally normalizes after successful parathyroidectomy, may persist in some patients. The factors associated with persistent calcium renal leak (cRL) have not been clarified.nnnOBJECTIVEnThe purpose of this study was to determine the prevalence of cRL in our 1HPT population and investigate cRL-related factors.nnnDESIGNnThis was a retrospective longitudinal study.nnnSETTINGnThe study was conducted in an outpatient setting.nnnPATIENTS/INTERVENTIONnThe participants were 95 patients with 1HPT successfully operated on who had a normal estimated glomerular filtration rate.nnnMAIN OUTCOME MEASURESnThe biochemical parameters of calcium metabolism and bone mineral density (BMD) measured by dual-X-ray absorptiometry before and 24 months after surgery were assessed. All histological findings were recorded.nnnRESULTSnThe prevalence of hypercalciuria before and after surgery was 74% and 32%, respectively. Before, surgery patients with cRL showed lower calcium and higher phosphate levels than those without cRL (10.9 ± 0.6 vs 11.4 ± 0.8 mg/dL [2.7 ± 0.2 vs 2.8 ± 0.2 mmol/L], P = .01 and 2.6 ± 0.5 vs 2.4 ± 0.4 mg/dL [0.84 ± 0.2 vs 0.77 ± 0.1 mmol/L], P = .04, respectively), whereas 24-h calciuria levels and the prevalence of 1HPT complications (osteoporosis, renal stones, and hypertension) were comparable. After surgery, serum calcium, phosphate, and PTH levels were comparable between patients with and without cRL. The prevalence of the histological finding of parathyroid hyperplasia was higher in patients with cRL (50%) than in patients without cRL (22%) (P = .01). The presence of cRL was independently associated with presurgery hypercalciuria (odds ratio, 4.71; 95% confidence interval, 1.18-18.8; P = .03) and parathyroid hyperplasia (odds ratio, 3.52; 95% confidence interval, 1.31-9.43; P = .01). Only patients without cRL had improved BMD at the spine (P = .04), total femur (P = .01), and femoral neck (P = .01).nnnCONCLUSIONSncRL is present in 30% of patients with 1HPT after successful surgery, and it is associated with parathyroid hyperplasia before surgery and the lack of improvement in BMD after surgery.