Impact of IGF(CA)19 gene polymorphism on the metabolic response to GH therapy in adult GH-deficient patients.

OBJECTIVE: A polymorphism in the promoter region of the IGF1 gene has been linked to serum IGF1 levels, risk of diabetes, and cardiovascular diseases with conflicting results. The aim of this study was to investigate the impact of this polymorphism on the short-term (1 year, n=98) and long-term (5 years, n=50) metabolic response to recombinant human GH (rhGH) in GH-deficient (GHD) adults. DESIGN AND METHODS: Prospective study on GHD adults. Different genotypes were studied by microsatellite method. According to the most frequent 192 bp allele (19 cytosine-adenosine-repeats), subjects were divided into homozygous (19/19), heterozygous (19/X), and noncarriers (X/X). RESULTS: Basal characteristics of patients as well as their response to rhGH in terms of decrease in body fat percentage and increase in IGF1 levels were not different in the three genotype-groups. Conversely, after 1-year rhGH, a significant worsening of insulin sensitivity (i.e. increase in fasting glucose levels and homeostasis model assessment of insulin resistance) and a significant improvement in lipid profile (i.e. reduction in total cholesterol and LDL-cholesterol) were recorded only in homozygous subjects. In the long-term, insulin sensitivity was restored in all the patients, while a significant improvement in lipid profile was observed in homozygous and heterozygous subjects, but not in noncarrier subjects. No difference in rhGH dose among groups was recorded throughout the study. CONCLUSIONS: In GHD adults, the presence of the WT allele in the IGF1 gene promoter may enhance sensitivity to either negative or positive metabolic changes induced by rhGH.

Vitamin D, parathyroid hormone and muscle impairment in myotonic dystrophies.

Parathyroid function in Myotonic Dystrophy (DM) patients has been poorly investigated. Parathyroid and muscle parameters were assessed in 31 male DM1 (44±2 years), 13 male DM2 (56±2 years) and 32 healthy controls. Hyperparathyroidism was diagnosed in 18% of patients without differences between DM types. In all DM patients, hyperparathyroidism was associated with normocalcemia but one with hypercalcemia. DM patients presented significantly higher PTH and lower vitamin D (25OHD) compared with controls, also considering seasonality. Severe vitamin D deficiency (25OHD<10 ng/ml) was diagnosed in 40% and hypovitaminosis D (25OHD<30 ng/ml) occurred in 88% of DM patients. About one-third of DM1 presented hypophosphatemia associated with elevated PTH levels. Serum 25OHD levels negatively correlated with PTH and with body fat mass. Considering DM1 patients, serum PTH levels positively correlated with CTG triplet repeats. Furthermore, PTH levels negatively correlated with total modified Medical Research Council (MRC) and positively with Muscular Impairment Rating Scale (MIRS). By contrast, in DM2 patients muscle assessment did not show any correlation with parathyroid function. In conclusion, we arrived at the following: 1) severe vitamin D deficiency is common in DM patients and it is associated with secondary hyperparathyroidism; 2) primary hyperparathyroidism, though rare, may occur; 3) increased adiposity in DM may be a risk factor for hypovitaminosis D; and 4) high serum PTH levels may indicate a muscle impairment, at least in DM1.

Epicardial fat thickness significantly decreases after short-term growth hormone (GH) replacement therapy in adults with GH deficiency.

BACKGROUND AND AIM: Growth Hormone Deficiency (GHD) is characterized by increased visceral fat accumulation. Echocardiographic epicardial fat thickness is a new marker of visceral adiposity. Aim of the present study was to evaluate whether epicardial fat thickness can significantly change and therefore serve as a marker of visceral fat reduction after short-term rhGH replacement therapy in patients with adult-onset GHD. METHODS AND RESULTS: Echocardiographic epicardial fat thickness was measured in 18 patients (10 M, 8 F, age 48 ± 11.8 yrs, BMI 29 ± 5.9 kg/m(2)) with adult-onset GHD, at baseline and after 6 and 12 months of rhGH therapy and in 18 healthy matched controls, at baseline. Echocardiographic epicardial fat thickness, conventional anthropometric and metabolic parameters, body fat percentage and quality of life were also evaluated. Epicardial fat thickness in adult GHD patients was higher than in controls (9.8 ± 2.8 vs 8 ± 3 mm, p < 0.05). Epicardial fat thickness significantly decreased after 6-months of rhGH replacement therapy (from 9.8 ± 2.8 to 7.0 ± 2.3 mm, P < 0.01, i.e. -29% from baseline). After 12 months of rhGH replacement therapy, epicardial fat thickness showed a further significant decrease (from 7.0 ± 2.3 to 5.9 ± 3.1 mm, P < 0.01, i.e. -40% from baseline). No significant changes in BMI or waist circumference after 6 or 12 months of rhGH therapy were observed. CONCLUSIONS: Echocardiographic epicardial fat thickness may represent a valuable and easy marker of visceral fat and visceral fat changes during rhGH replacement treatment in patients with adult-onset growth hormone deficiency.

Increased risk for non-autoimmune hypothyroidism in young patients with congenital heart defects.

CONTEXT: Newborns with congenital hypothyroidism (CH) have an increased risk for congenital heart defects (CHD) due to a common embryonic developmental program between thyroid gland and heart and great vessels. OBJECTIVE: Our objective was to investigate the prevalence and origin of thyroid disorders in young patients with CHD. DESIGN AND SETTING: We conducted a prospective observational study between January 2007 and January 2009 in academic Pediatric Cardiosurgery and Endocrinology. PATIENTS: Patients included 324 children (164 males, 160 females, aged 0.2-15.4 yrs) with CHD. INTERVENTION: Subjects underwent hormonal and genetic screening. MAIN OUTCOME MEASURES: Serum TSH and thyroid hormone levels were assessed. RESULTS: Two CHD patients were diagnosed with CH at the neonatal screening (1:162). Mild hypothyroidism (serum TSH > 4.0 µU/ml) was diagnosed and confirmed 6 months later [TSH = 5.4 ± 1.5 µU/ml; free T(4) = 1.3 ± 0.2 ng/dl (normal values 0.8-1.9)] in 37 children (11.5%) who were negative at neonatal screening. Hypothyroidism was not related to type of CHD, whereas TSH levels positively correlated with serum N-terminal pro-type B natriuretic peptide levels. Biochemical and ultrasound findings consistent with thyroid autoimmunity were present in three of 37 hypothyroid children (8.1%). One patient had hemiagenesis (2.7%). Variations in candidate genes were screened in CHD patients. NKX2.5 coding sequence was normal in all samples. A 3-Mb microdeletion in 22q11.2 was detected in three patients (8.3%), whereas only known polymorphisms were identified in TBX1 coding sequence. CONCLUSIONS: CHD patients have an increased risk for both CH (10-fold higher) and acquired mild hypothyroidism (3-fold higher). Unrecognized mild hypothyroidism may negatively affect the outcome of CHD children, suggesting that thyroid function should be repeatedly checked. Thyroid autoimmunity and 22q11.2 microdeletions account for small percentages of these cases, and still unknown mechanisms underline such a strong association.

[Thyroid function and obesity]. / La funzione tiroidea in corso di obesità.

A relationship between thyroid function and obesity seems likely, mainly influenced by the insulin resistance. Whether variations in TSH and/or thyroid hormones, within a normal range, can influence body weight or if obesity per se can alter thyroid function has not been clarified so far. Further studies are necessary to assess the link between thyroid function and body weight, that must consider not only changes of thyroid hormones, but also body fat distribution, obesity duration and the state of low grade inflammation. It is recognized that thyroid function is linked not only to body mass index, but also to body composition and, particularly, to the amount and percentage of fat mass.

Relationship of thyroid function with body mass index and insulin-resistance in euthyroid obese subjects.

BACKGROUND AND AIMS: It is recognized that overt thyroid dysfunction is associated with weight changes, but the influence of a minor alteration of thyroid function remains unclear. This study aimed to further investigate the relationship between obesity and thyroid function and to examine the possible role of insulin resistance on the hypothalamic-pituitary- thyroid axis. METHODS AND RESULTS: Serum TSH and free T4 (FT4) levels, anthropometric and metabolic parameters were evaluated in 581 obese patients. In all patients TSH values progressively increased according to the severity of obesity and were positively correlated with body mass index (p=0.001, r=0.13) and waist circumference (p=0.02, r=0.11). Patients with insulin resistance showed higher TSH (1.8±1.0 vs 1.6±0.9 µUI/l; p=0.03) and lower FT4 levels (13.8±2.3 vs 15.0±2.2 pmol/l; p<0.001), as compared with patients with normal insulin sensitivity. Moreover, TSH was positively correlated with fasting insulin (p<0.001, r=0.152) and homeostasis model assessment of insulin resistance (HOMA-IR; p<0.001, r=0.148), and negatively correlated with Quantitative Insulin Sensitivity Check Index (QUICKI; p<0.001, r=-0.148); FT4 was negatively associated with fasting insulin (p<0.001, r=-0.287) and HOMA-IR (p<0.001, r=-0.295), and positively associated with QUICKI (p<0.001, r=0.295). CONCLUSIONS: A relationship between thyroid function and overweight/ obesity condition seems to exist, mainly influenced by insulin resistance. Whether variations in TSH and/or thyroid hormones, within a normal range, can influence body weight or whether obesity per se can alter thyroid function cannot be stated so far. Further studies are needed to assess the link between thyroid function and body weight, by considering not only changes in thyroid hormones, but also body fat distribution, obesity duration and low-grade inflammation.

Subclinical hypercortisolism: correlation between biochemical diagnostic criteria and clinical aspects.

OBJECTIVE: Subclinical hypercortisolism (SH) has been associated with increased prevalence of hypertension, type 2 diabetes mellitus, dyslipidaemia, central obesity, osteoporosis and vertebral fractures. We aimed to investigate the accuracy of different SH diagnostic criteria in predicting the presence of complications. DESIGN: This was a retrospective study. PATIENTS: We evaluated data from 231 patients (120 women and 111 men) affected with adrenal incidentalomas (AI). MEASUREMENTS: We studied the accuracy of different SH diagnostic criteria (cortisol after 1 mg overnight dexamethasone suppression test - 1mg-DST - at different cut-off such as 49.7, 82.8, 137.9 nmol/l, elevated urinary free cortisol, reduced adrenal corticotroph hormone (ACTH) levels alone or various combination of these parameters) in predicting the concomitant presence of the following three complications: hypertension, type 2 diabetes and vertebral fractures. RESULTS: The criterion characterized by the presence of two of 1mg-DST >82.8 nmol/l, elevated UFC and reduced ACTH struck the best balance between sensitivity and specificity, reaching a good accuracy in predicting the cluster of complications (61.9%; 77.1% and 75.8%, respectively). The presence of this cluster was associated with this criterion (OR 4.75, 95%CI 1.8-12.7, P = 0.002) regardless of gonadal status, body mass index (BMI) and age. CONCLUSIONS: The SH criterion characterized by the presence of two of 1mg-DST >82.8 nmol/l, elevated UFC and reduced ACTH seems the best in predicting the presence of chronic manifestations of subtle cortisol excess.

Peripheral insulin-like factor 3 concentrations are reduced in men with type 2 diabetes mellitus: effect of glycemic control and visceral adiposity on Leydig cell function.

BACKGROUND AND AIM: Hypogonadism frequently occurs in men with type 2 diabetes mellitus (T2DM), while the role of glycemic control and visceral obesity is still unclear. This study aimed to assess the Leydig cell function, including the new sensitive marker insulin-like factor 3 (INSL3), in T2DM patients without overt hypogonadism and the influence of either glycemic control or visceral adiposity. SUBJECTS AND METHODS: Thirty T2DM patients (age 57.1+/-6.2 years, body mass index (BMI) 28.0+/-4.3) without overt hypogonadism and 30 age- and BMI-matched controls were studied. Anthropometric, glycometabolic parameters and testosterone, SHBG, LH, INSL3 levels, bioavailable and free testosterone (BT and cFT) were evaluated. The human chorionic gonadotrophin (hCG) test was also performed. RESULTS: Patients had lower total testosterone (452.6+/-130.0 vs 512.6+/-117.3 ng/dl, P=0.06), BT (189.7+/-36.4 vs 237.1+/-94.1 ng/dl, P=0.002), cFT (8.1+/-1.6 vs 10.1+/-4.0 ng/dl, P=0.002), and higher LH levels (3.5+/-1.6 vs 2.6+/-1.2 mU/ml, P=0.01) versus controls. Serum INSL3 concentrations were also lower in patients (1.1+/-0.3 vs 1.5+/-0.7 ng/ml, P=0.01). These hormonal parameters, including INSL3, did not differ between T2DM patients with poor or good glycemic control (HbA1c>9 or <7% respectively). In patients, waist circumferences (97.9+/-12.4 cm) negatively correlated with INSL3 (P=0.03) and basal, as well as hCG-stimulated testosterone levels (P=0.04 and 0.004 respectively). Basal or stimulated hormonal levels and INSL3 concentrations were not different between patients with (40%) or without erectile dysfunction. CONCLUSIONS: An early impairment of the overall Leydig cell function is present in men with T2DM, mainly related to visceral adiposity rather than to glycemic control.

Analysis of GNAS1 and PRKAR1A gene mutations in human cardiac myxomas not associated with multiple endocrine disorders.

Cardiac myxomas are rare tumors that usually occur as sporadic lesions or,more rarely, in the familial form,mostly in the context of Carney complex (CNC). The molecular basis for the development of cardiac myxomas is unclear. However, somatic activating mutations in the GNAS1 gene (the gsp oncogene) are detected in the myocardium ofMcCune-Albright syndrome patients while germ-line mutations in the PRKAR1A gene are associated with CNC and familial myxomas. We investigated the presence of activating missense mutations in the GNAS1 gene as well as of inactivating mutations in PRKAR1A in 29 sporadically occurring cardiac myxomas. No gsp and no PRKAR1A mutations were found by direct sequencing of PCR products amplified from tumoral DNA. This is the first study including a large series of sporadic, isolated cardiac myxomas and showing that these cardiac neoplasms do not share the same mutations found in familial forms.

Prevalence of GH deficiency in cured acromegalic patients: impact of different previous treatments.

OBJECTIVE: Radiotherapy (RT) for pituitary adenomas, including GH-secreting ones, frequently leads to GH deficiency (GHD). Data on the effects of surgery alone (S) on dynamic GH secretion are limited. The aim of the study was to investigate the occurrence of GHD in acromegalic patients treated with different therapeutic options. DESIGN AND METHODS: Fifty-six patients in remission from acromegaly, (33 F & 23 M, age: 54+/-13 years, body mass index (BMI): 28.4+/-4.1 kg/m(2), 21 with adequately substituted pituitary deficiencies) treated by S alone (n=33, group 1) or followed by RT (n=23, group 2), were investigated for GHD by GHRH plus arginine testing, using BMI-adjusted cut-offs. Several metabolic and cardiovascular parameters (waist circumference, body fat percentage, blood pressure, fasting and post-oral glucose tolerance test glucose, HbA1c, insulin resistance and lipid profile) were evaluated in all the patients and 28 control subjects with known diagnosis of GHD. RESULTS: Serum GH peak after challenge was 8.0+/-9.7 microg/l, without any correlation with post-glucose GH nadir and IGF-1 levels. The GH response indicated severe GHD in 34 patients (61%) and partial GHD in 15 patients (27%). IGF-1 were below the normal range in 14 patients (25%). The frequency of GHD was similar in the two treatment groups (54% in group 1 and 70% in group 2). No significant differences in metabolic parameters were observed between acromegalic patients and controls with GHD. CONCLUSIONS: Severe GHD may occur in about 60% of patients treated for acromegaly, even when cured after S alone. Thus, a stimulation test (i.e. GHRH plus arginine) is recommended in all cured acromegalic patients, independently from previous treatment.

Echocardiographic alterations in patients with non-functioning adrenal incidentaloma.

OBJECTIVE: While left ventricular (LV) dysfunction has been described in patients with Cushing's syndrome (CS), data concerning morphologic and functional cardiac alterations in patients with incidentally discovered adrenal masses [adrenal "incidentaloma" (AI)], without overt hypercortisolism, are lacking. In this study the echocardiographic characteristics of patients with AI were evaluated and then compared with those of lean and obese normotensive subjects. SUBJECTS AND METHODS: Twenty-one patients with AI, without clinical or subclinical hypercortisolism, 18 normotensive obese subjects matched for gender and body mass index (BMI) and 20 normotensive lean subjects were studied. Echocardiography was performed in all subjects. In all patients plasma ACTH, serum cortisol, and DHEA-S levels were measured. RESULTS: Patients with AI showed greater impairment of several echocardiographic indices of LV hypertrophy and diastolic dysfunction compared to normotensive lean subjects (p<0.05), but did not differ from those in obese subjects. Hypertensive AI patients showed a greater alteration of echocardiographic parameters (p<0.05) and higher BMI (p<0.01) and cortisol values (p<0.05) than normotensive ones. Plasma ACTH and serum cortisol were similar in AI patients and in obese controls, while DHEA-S levels were lower in AI (p<0.05). No correlations between cortisol secretion and echocardiographic parameters were found. CONCLUSION: In patients with non-functioning AI there is an impairment of cardiac morphology and function. These data suggest that patients with AI should be carefully screened also by means of echocardiographic studies.

Soluble adhesion molecules levels in patients with Cushing's syndrome before and after cure.

OBJECTIVE: Patients with Cushing's syndrome (CS) show a high prevalence of cardiovascular risk factors and atherosclerosis, persisting even after cure. Soluble intercellular adhesion molecule-1 (sICAM-1) and vascular cell adhesion molecule-1 (sVCAM-1) are surrogate markers of endothelial function involved in the initiation of atherosclerosis. This study aimed to evaluate sICAM-1 and sVCAM-1 levels in patients with CS before and after successful cure. SUBJECTS AND METHODS: sICAM-1 and sVCAM-1 levels were evaluated in 28 patients with active CS and in 12 patients with Cushing's disease (CD), 6-12 months after disease remission. Body mass index (BMI), blood pressure, glucose, serum lipids, ACTH, cortisol and urinary free cortisol (UFC) were measured in basal conditions in all patients. RESULTS: At baseline, sICAM-1 levels positively correlated with BMI (r=0.443, p<0.01), while no correlations between sICAM/sVCAM levels and ACTH, cortisol or UFC were found. Plasma ACTH, serum cortisol, and UFC levels significantly decreased in 12 cured patients, but ICAM-1 and VCAM-1 levels were unchanged (12.7+/-1.8 vs 10.1+/-0.9 ng/ml and 33.5+/-4.4 vs 35.8+/-4.0 ng/ml, respectively). Obesity, hypertension, and impaired glucose metabolism persisted 1 yr after the biochemical cure of hypercortisolism. A significant reduction in ICAM-1 levels was observed in 4 out of 12 cured patients as well as a remission from diabetes, hypertension or obesity. CONCLUSIONS: ICAM/VCAM-1 levels show a great variability in patients with active CS, not correlated with cortisol levels, and are slightly modified in some cured patients with CD. The persistence of obesity, hypertension, and impaired glucose metabolism may be responsible for the maintenance of a subclinical endothelial dysfunction, making these subjects still at high cardiovascular risk and needing a long-term follow-up.

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 < or =3 mg/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.

Evaluation of proopiomelanocortin mRNA in the peripheral blood from patients with Cushing's syndrome of different origin.

ACTH-dependent Cushing's syndrome is due to ACTH overproduction originating from a pituitary corticotroph adenoma (Cushing's disease) or from ectopic tumors (ectopic ACTH syndrome). Due to difficulties in the differential diagnosis between these two forms of hypercortisolism it would be important to have molecular tools able to discriminate the two conditions. It is known that proopiomelanocortin (POMC) gene transcription can originate messengers of different length. ACTHomas show the normal 1072 nucleotides (nt) transcript, whereas ectopic tumors seem to be associated with a longer mRNA form (1450 nt). In order to analyse the presence of different POMC transcripts, we extracted total RNA from peripheral lymphocytes of 10 patients with Cushing's disease, 10 with ectopic Cushing syndrome, and 20 controls as well as from pituitary tissues (2 ACTH-omas and a normal pituitary polyA+ sample). Northern blot analysis correctly revealed a 1072 nt mRNA molecule in pituitary ACTH-oma and in the normal pituitary polyA+ RNA samples, whereas neither this molecule nor other alternative transcripts were detected in blood samples from patients and controls. These data were confirmed by the more sensitive RT-PCR technique. This study further underlines the need for alternative approaches in the diagnosis of ACTH-dependent Cushing's syndrome.