Paola Franceschetti

Evaluation of Hormonal Function in a Series of Incidentally Discovered Adrenal Masses

The discovery of an asymptomatic adrenal mass (incidentaloma) during the investigation of an unrelated condition is relatively common. In this study, we report the clinical, radiologic, and endocrine evaluation of 38 patients (22 women and 16 men aged 24 to 84 years) with adrenal incidentaloma (size, 1 to 12 cm). The patients underwent basal and dynamic evaluation of the hypothalamic-pituitary-adrenal (HPA) axis, renin-angiotensin-aldosterone system, and adrenomedullary function. Moreover, computed tomograpy (CT) scan and 131I-6beta-iodomethyl-19-norcholest-5(10)-en-3beta-ol(NP-59) and/or 131I-metaiodobenzylguanidine (MIBG) scintigraphy were performed. The endocrine evaluation indicated two cases of pheochromocytoma and four cases of preclinical Cushings syndrome, three of which underwent surgery with histologic diagnosis of two adrenocortical adenomas and one carcinoma. Low levels of serum dehydroepiandrosterone sulfate (DHEA-S), associated with a markedly increased 17-hydroxyprogesterone (17-OHP) response to a corticotropin (ACTH) test, were found in patients with incidentaloma. On the basis of endocrine and morphologic data, 13 patients underwent surgical treatment: five adrenocortical adenomas (two functioning), two pheochromocytomas, two ganglioneuromas, one cortisol-secreting adrenal carcinoma, one lymphangiomatous cyst, one myelolipoma, and one hemorrhage were found. Careful diagnostic assessment of incidentally discovered adrenal masses must be performed to exclude the presence of malignant and/or functioning lesions and to verify the possibility that patients with incidentaloma have a genetic or acquired deficit of adrenal steroidogenic activity.

Activation of the Somatotropic Axis by Testosterone in Adult Men: Evidence for a Role of Hypothalamic Growth Hormone-Releasing Hormone

Testosterone (T) is known to affect the growth hormone (GH) axis. However, the mechanisms underlying the activation of GH secretion by T still remain to be clarified. Available data in animals and humans have shown that withdrawal of somatostatin (SRIH) infusion induces a GH-releasing hormone (GHRH)-mediated rebound release of GH, and there is accumulating evidence that SRIH infusion withdrawal may be a useful test to probe the GHRH function in vivo. With the aim of investigating whether the stimulatory effect of androgens on GH release in man could be accounted for by activation of the hypothalamic GHRH tone, we evaluated the plasma GH response to SRIH withdrawal in 10 patients aged 29.6 ± 2.4 years (mean ± SEM), diagnosed with hypergonadotropic hypogonadism, before and after a 6-month replacement therapy with T enanthate (250 mg every 3 weeks, i.m.), and in 10 healthy men, aged 26.7 ± 2.8 years. To verify whether the modulation of GH secretion by T could also be mediated through changes in SRIH tone and/or pituitary releasable pool, we examined GH secretory responses to combined GHRH and L-arginine (ARG) in the same individuals. Basal plasma concentrations of GH (0.48 ± 0.11 µg/l) and IGF-I (23.79 ± 1.83 nmol/l) were significantly lower in untreated hypogonadal patients than in healthy men, and significantly increased after T replacement therapy (GH 1.13 ± 0.28 µg/l; IGF-I 28.71 ± 1.46 nmol/l). The mean ΔGH peak after SRIH withdrawal recorded in untreated hypogonadal men (2.65 ± 0.86 µg/l) was significantly (p < 0.05) lower than that observed in healthy men (6.53 ± 1.33 µg/l) and significantly increased after T replacement therapy (5.52 ± 1.25 µg/l). The GH responses to GHRH combined with ARG (a functional SRIH antagonist) were not significantly different between healthy men and untreated hypogonadal patients, and were not significantly affected by T treatment. Plasma T and estradiol (E2) levels significantly correlated with ΔGH peak after SRIH withdrawal in healthy men and in T-treated hypogonadal patients, whereas in untreated patients they did not. No significant correlation was found between GH areas under the curve after GHRH + ARG test and T and E2 plasma levels in either healthy men or in hypogonadal patients (both before and after T replacement). These findings are consistent with the view that in humans the stimulatory action of T on the GH axis appears to be mediated at the hypothalamic level primarily by promoting GHRH function.

Risk factors for development of atypical femoral fractures in patients on long-term oral bisphosphonate therapy

Bisphosphonates (BPs) are the first-line therapy for osteoporosis. In recent years, atypical femoral fractures (AFF) have been described in patients on BPs therapy. However, the relationship between BPs and AFF remains to be clarified. We evaluated clinical and hormonal characteristics of AFF patients, in order to determine AFF risk factors. We studied 11 females with AFF and 58 females with typical femoral fractures (TFF), admitted to our Department for surgical repair between January 2008 and December 2011. All AFF patients received BPs therapy for 6 to 13 yrs, whereas 36.2% (p<0.0001) of TFF patients received BPs for shorter period (TFF, 6.1±1.8 yr vs. AFF, 8.6±1.9 yr, p<0.0001). A higher prevalence of hypocalcemia was observed in AFF patients compared with TFF (p<0.02), with significantly (p<0.05) lower corrected calcium levels in AFF patients. By contrast a reduced prevalence of elevated PTH levels (p<0.05) was found in AFF patients. No significant difference in prevalence of vitamin D defect was observed between the two groups. Younger age (p<0.004), higher BMI (>30 kg/m2, p<0.03) and early menopausal age (p<0.05) were observed in AFF patients. At time of fracture, prevalence of osteopenia/osteoporosis and levels of bone turnover markers were significantly (p<0.01) lower in AFF compared with TFF patients. By multivariate analysis hypocalcemia, obesity, and younger age (<70 yr) were confirmed to be independent predictors of AFF; elevated PTH level was the predominant independent protective factor (p<0.004). In conclusion, our data indicate that clinical characteristics and metabolic factors may favor the development of AFF in BP treated patients. We identified hypocalcemia due to latent hypoparathyroidism as primary risk factor for AFF; age, obesity, early menopause, and BMD may also influence the development of AFF. An adequate clinical and metabolic assessment is suggested to prevent the development of AFF in BP treated patients.

Retinoic acid-induced decrease of DNA synthesis and peroxidase mRNA levels in human thyroid cells expressing retinoic acid receptor alpha mRNA

In order to clarify the effect of retinoids on thyroid cell growth and function, the presence of retinoic acid receptors (RARs) and the action of retinoic acid (RA) on DNA synthesis and on thyroid peroxidase (TPO) and thyroglobulin (TGB) mRNA expression were investigated in primary cultures of human thyroid follicular cells. A time and dose-dependent reduction in 3H-thymidine (3H-thy) incorporation was found in cells exposed for 48 h to all-trans-RA up to 1 microM. A cytotoxic effect was found only with the higher dose of 50 microM. The RA-induced decrease of 3H-thy incorporation was reflected by parallel change in DNA content of cell monolayers. The inhibitory effect of 1 microM RA on 3H-thy incorporation ranged from 28.5 +/- 4.6% in normal cells to 42 +/- 3.2% in adenomatous cells. In addition, 1 microM RA significantly reduced basal and TSH-induced TPO mRNA levels in normal, goitrous and adenomatous cells, but did not alter TGB mRNA levels. Furthermore, in these cells the study of RAR alpha and beta mRNA showed the presence of two major RAR alpha mRNA transcripts of approximately 3.5 and 2.8 Kb in size, whereas RAR beta mRNA was undetectable. Overall, our data indicate that RAR alpha gene is expressed in human thyrocytes and that RA may be involved in the regulation of the human thyroid by reducing proliferation and function of follicular cells.

Acute administration of human galanin in normal subjects reduces the potentiating effect of pyridostigmine-induced cholinergic enhancement on release of norepinephrine and pancreatic polypeptide.

The neuropeptide galanin (GAL) is widely distributed in the central and peripheral nervous systems where it often coexists with catecholamines and acetylcholine. Recently we have reported that human GAL (hGAL) in man depresses the release of norepinephrine (NE) and the responses to both assumption of upright posture and insulin-induced hypoglycemia. To gain an insight into the action of hGAL on sympathetic nervous system activity in man, we investigated the effects of a 60-min infusion (80 pmol/kg/min) of hGAL or saline on the release of NE, epinephrine (E) and pancreatic polypeptide (PP) induced by an acetylcholinesterase inhibitor, pyridostigmine bromide (PD), in nine healthy volunteers. PD (120 mg orally) induced a significant rise in plasma concentrations of NE (1.6 +/- 0.04 vs. 1.08 +/- 0.06 nmol/l), E (0.34 +/ 0.05 vs. 0.12 +/- 0.04 nmol/l) and PP (178.06 +/- 33 vs. 37.57 +/- 7.35 pmol/l), whilst it significantly reduced heart rate (HR; 61 +/- 2 vs. 71 +/- 4 beats/min). Changes in plasma levels of PP were determined as an indirect measure of amplification of endogenous cholinergic activity produced by PD. Administration of hGAL blunted the release of NE and PP evoked by PD. The mean (+/- SEM) area under the curve produced by PD of NE (50.05 +/- 3.97 nmol/l.90 min) and PP (8,692.87 +/- 1,724 pmol/l.90 min) was significantly (p < 0.001) reduced by hGAL infusion (2.65 +/- 1.57 nmol/l.90 min and 248.1 +/- 148 pmol/l.90 min, for NE and PP, respectively). hGAL failed to affect significantly the E release evoked by PD. hGAL was able to enhance HR significantly (104 +/- 5 vs. 69 +/- 3 beats/min), and completely prevented the PD-induced slowing of HR. Both PD and hGAL did not alter supine systolic and diastolic blood pressure. We conclude that hGAL significantly reduces the release of NE and PP stimulated by PD-induced enhancement of cholinergic activity. These findings are consistent with a functional interrelationship between GAL and the cholinergic system in man, and may suggest the participation of a cholinergic pathway in the galaninergic modulation of the autonomic nervous system.

Evaluation of the Role of BRAF V600E Somatic Mutation on Papillary Thyroid Cancer Disease Persistence: A Prospective Study

Background: BRAFV600E (c.1799T>A) somatic mutation evaluation in fine needle aspiration biopsies (FNAB) is a powerful diagnostic tool in the settings of papillary thyroid cancer (PTC). However, its prognostic value is still a matter of great debate and has been addressed mostly in retrospective studies. Objectives: To evaluate whether the somatic BRAFV600E mutation, assessed by direct sequencing in FNAB material of thyroid nodules, may correlate with disease persistence in PTC patients. Study Design: We conducted a prospective cohort study investigating 160 PTC patients previously assessed for the somatic BRAFV600E mutation, and submitted to total thyroidectomy, with a follow-up of 2–10 years. Patients were matched according to somatic BRAFV600E mutation (80 BRAF+ and 80 BRAF– patients) and to the presence (LN+, 40 patients each group) or absence (LN, 40 patients each group) of neck lymphnode metastases. Disease persistence was considered according to basal or TSH-stimulated Thyroglobulin (TG) levels, anti-TG antibodies, neck ultrasound, CT scan where applicable and whole body scan after radioiodine ablation treatment (RAI). Results: The presence of the somatic BRAFV600E mutation did not influence the indication for RAI. None of the enrolled patients showed disease recurrence or died due to disease-related causes. During follow-up, disease persistence did not correlate with the presence of somatic BRAFV600E mutation both in patients submitted to RAI nor in those treated more conservatively. Conclusions: The somatic BRAFV600E mutation does not associate with a worse prognosis in low risk PTC and, in our settings, may not be considered an independent risk factor for disease persistence.

Growth Hormone and Skeletal Muscle Function

It is well established that skeletal muscle is a target tissue for GH, and there is a wealth of literature concerning the influence played by GH on the musculoskeletal system. It is now widely recognized that GH-Insulin-like growth factor-I (IGF-I) axis has an important role in controlling the growth and differentation of skeletal muscle. Recently, this topic was extensively reviewed by Florini et al (1). As early as 1934, it was reported that administration of anterior pituitary extracts in rats increases muscle mass (2). These observations were confirmed by Plattener and Reed (3), who found that, in rats, treatment with “anterior pituitary growth factor” leads to an increase in muscle mass, but does not affect muscle performance. Accordingly, rats treated with 500 µg GH/day for 3 weeks gained significantly more than controls, and their quadriceps muscles were 15-40% heavier, although muscle performance did not change (4). In hypophysectomized animals GH administration has induced an increase in muscle mass and activity of polyribosomes, indicative of enhanced muscle protein synthesis (5). The strong link between GH and skeletal muscle growth has been convincingly demonstrated by Palmer et al (6) who provided clear evidence that intact rats treated with a polyclonal antiserum to rat GH exhibit a marked reduction in weight, total protein and RNA content of hind limb muscle. Futhermore, it is also well known that hypophysectomized rats have a decrease in the levels of mRNA for all forms of myosin heavy chain (MCH) that is partially remedied by GH (7). The mode of action on skeletal muscle, however, still remains unclear. Although, the somatomedin hypothesis implies that many of the biological activities of GH are mediated by IGFs, which could regulate the proliferation and differentiation of skeletal muscle cell, a direct effect of GH on muscle cannot be excluded.