E. De Carlo

Endothelin-1 and endothelin-3 stimulate insulin release by isolated rat pancreatic islets

Endothelins (ETs) are potent vasoconstrictive peptides released from the endothelium and other tissues, which act on target cells by receptorial calcium-mediated mechanisms. ET-1 levels are increased in diabetes, and observations suggest the involvement of ETs in the pathogenesis of diabetic angiopathy. However, it is not possible to exclude that ETs might also influence insulin secretion or function. In vivo infusion of ET-1 in rats induces hypoglycaemia and hyperinsulinemia and in vitro incubation with ET-1 stimulates insulin release by mouse islets. Therefore, ETs might be involved in a circulus vitiosus, resulting in hyperinsulinemia and diabetic angiopathy. The purpose of our study was to verify the effect of ET-1 on rat islets, in both the presence and absence of physiological glucose concentration. Moreover, we tested the effect of another isoform of endothelins, ET-3, and verified the involvement of extracellular calcium in such events. Islets were incubated with increasing ET-1 or ET-3, with or without glucose 5.6 mM. Other samples were prepared using calcium- free medium. Incubation in medium containing ET-1 and ET-3, in the presence of glucose and calcium, induced an increase in insulin release. When ET-1 and ET-3 were incubated without glucose and calcium, insulin release was not modified. Our studies demonstrate that: 1) ET-3, like ET-1, stimulates insulin release by rat isolated islets; 2) direct insulin stimulating effect on islets of both ET-1 and ET-3 is evident with physiological glucose concentrations and is calcium mediated. These results support the hypothesis of ET involvement in the regulation of insulin secretion.

Effect of exercise on plasma kallikrein and muscular phospholipase A2 activity in rats.

Many experimental observations show that prolonged physical exercise produces an increase of muscular glucose uptake. Recent findings suggest that the kallikrein-kinin-prostaglandin system may be related to this phenomenon, but so far, no direct evidence of quantitative alteration in this system has been observed during exercise. We measured plasma kallikrein and muscular phospholipase A2 activity, respectively the first and the last steps of reactions leading to prostaglandin synthesis. We demonstrated, for the first time, that during exercise plasma kallikrein activity increases in rats. We also observed an increase of muscular phospholipase A2 activity after exercise and a positive correlation between these parameters. Our findings demonstrate, under physiological conditions of enhanced muscular glucose uptake, a concomitant significant increase of plasma kallikrein and muscular phospholipase A2 activity, supporting the hypothesis that activation of the kallikrein-kinin-prostaglandin system may play some part in the enhanced muscular glucose uptake during physical activity.

The early diagnosis of multiple endocrine neoplasia type 1 (MEN 1): A case report

We report the case of a patient presenting amenorrhea, hyperprolactinemia, headache and nuclear magnetic resonance (NMR) evidence of pituitary macroadenoma. The family history revealed that the patient’s father had had a referred sporadic insulinoma, removed 25 yr before without evidence of other endocrine disorders. Physical examination evidenced a slight neck enlargement. Among biochemical and endocrinological assays performed, only hyperprolactinemia was observed. Neck ultrasonography (US) revealed a parathyroid enlargement and a 99mTcO4/MIBI scan showed two hyperplasic lesions. Considering the diagnostic suspect of multiple endocrine neoplasia (MEN1), we performed abdominal US and NMR studies, showing a pancreatic lesion compatible with neuroendocrine tumor. A total body 111In-DTPA-d-Phe1-octreotide scan (Octreoscan®) was also carried out, evidencing no pituitary tumor uptake but high uptake of the abdominal lesion. After surgery, the histological examination confirmed the two parathyroid adenomas and four non-functioning pancreatic neuroendocrine tumors. When the patient was admitted for studying the pituitary lesion and for planning the opportune therapy, an early and partially subclinical stage of MEN1 was identified, potentially already clear but otherwise undiagnosed, and the genetic state of the patient’s relatives, as possible carriers of DNA mutation, was checked. The DNA study for germline mutations confirmed the clinical diagnosis of MEN1 syndrome in the patient and evidenced the same MEN1 mutation in her father and twin sister. In this case report, we would like to underline that, still today, a correct anamnesis and physical examination are the cornerstone of clinical approach to the patient. Furthermore, initial good practice approach is necessary to plan the diagnostic iter, enabling clinicians to decide upon the best orientation and interpretation of the results among several complicated and expensive exams.

Brain anatomical substrates of mirror movements in Kallmann syndrome.

Among male patients affected by Kallmann syndrome, a genetically determined disease due to defective neural migration leading to hypogonadropic hypogonadism and hypo/anosmia, about 40% present the peculiar phenomenon of mirror movements, i.e. involuntary movements mirroring contralateral voluntary hand movements. Several pathogenic hypotheses have been proposed, but the ultimate neurological mechanisms are still elusive. The aim of the present study was to investigate brain anatomical substrates of mirror movements in Kallmann syndrome by means of a panel of quantitative MRI analyses. Forty-nine male Kallmann syndrome patients underwent brain MRI. The study protocol included 3D-T1-weighted gradient echo, fluid attenuated inversion recovery and diffusion tensor imaging. Voxel-based morphometry, sulcation, curvature and cortical thickness analyses and tract based spatial statistics were performed using SPM8, Freesurfer and FSL. All patients underwent a complete physical and neurological examination including the evaluation of mirror movements (according to the Woods and Teuber criteria). Kallmann syndrome patients presenting with mirror movements (16/49, 32%) displayed the following brain changes: 1) increased gray matter density in the depth of the left precentral sulcus behind the middle frontal gyrus; 2) decreased cortical thickness in the precentral gyrus bilaterally, in the depth of right precentral sulcus and in the posterior portion of the right superior frontal gyrus; and 3) decreased fractional anisotropy in the left hemisphere involving the temporal lobe and peritrigonal white matter. No differences were shown by cortical curvature and sulcation analyses. The composite array of brain changes observed in Kallmann syndrome patients with mirror movements likely represents the anatomical-structural underpinnings leading to the peculiar derangement of the complex circuitry committed to unilateral hand voluntary movements.

Isolated R171Q amino acid change in MEN1 gene: polymorphism or mutation?

The change of amino acid arginine to glutamine at position 171 (R171Q) in exon 3 of MEN1 gene occurs in the general population with a frequency ranging from 1·4% to 5%, and has been occasionally reported in MEN1 carriers and in tissues from sporadic MEN1 endocrine tumours. 1–3 It is unclear whether an isolated R171Q amino acid change represents a polymorphism and/or it has a role in tumourigenesis. Recently, Balogh et al . 4 reported the R171Q amino acid change in germline DNA of six out of 32 subjects with MEN1 or MEN1-related states. Specifically, the R171Q amino acid change was associated with three novel MEN1 gene mutations (L301R, C354X and G28A) in two familial and one sporadic MEN1 cases, and was found to be the only MEN1 gene alteration in other three subjects with sporadic MEN1-related state. We report a case of a 46-year-old woman who came to our observation for recurrent primary hyperparathyroidism (PHPT). Three years before she underwent surgery for a parathyroid adenoma, a nonfunctioning pancreatic neuroendocrine tumour and a nonfunctioning adrenocortical adenoma. A MEN1 syndrome was diagnosed, but neither DNA analysis in the patient nor clinical investigations in the patient’s relatives were available. Thus, studying family history in depth, we found that a few years earlier the patient’s sister had undergone surgery for both a prolactin-secreting pituitary adenoma and PHPT due to parathyroid adenoma. The patient’s father died for liver cirrhosis when he was 46 years old and during his life was affected by recurrent gastric ulcerations requiring gastrectomy. A patient’s paternal aunt died for a cerebral mass, referred as a probable pituitary tumour causing amenorrhoea and blindness. We performed the MEN1 germline gene analysis by direct DNA sequencing, as previously described, 5 in the proband, in the two sisters and in their brother. In all cases sequence analysis revealed an isolated G > A transition at codon 171 of exon 3, resulting in the replacement of arginine (CGG) with glutamine (CAG). Clinical investigation of the brother was negative for MEN1 features. The same gene alteration was also demonstrated in her brother’s daughter, who had no clinical signs of disease. The R171Q amino acid change was found in an unrelated MEN1 proband (affected by a parathyroid adenoma and an ACTH-secreting pituitary adenoma) from a different family, in her two sons (one with PHPT and a nonfunctioning pituitary adenoma) and in the father, not clinically affected. The relationship between the two MEN1 families studied was excluded by the study of genealogic trees. Unfortunately, no tumour tissue from any of our patients was available to analyse the possible somatic loss of wild-type allele, in accordance with the Knudson two-hit hypothesis. As controls, a panel of 50 healthy Italian subjects, that is, 100 alleles, from the same geographical area was then screened, and the R171Q amino acid change in the MEN1 gene was not detected. Written informed consent for genetic testing was obtained from all patients and control subjects. More than 400 germline and somatic mutations have been identified in sporadic, familial MEN1 and MEN1-related states. 1–3

Graves’ ophthalmopathy and atrophic thyroiditis: A case report

Graves’ ophthalmopathy (GO) — also known as thyroid-associated orbitopathy or ophthalmopathy — usually affects patients with Graves’ disease. Antibodies stimulating the TSH receptor are thought to be involved in the pathogenesis of this important and disabling extra-thyroidal manifestation of Graves’ disease. Less frequently, GO occurs in subjects who neither have nor have ever shown evidence of thyroid dysfunction (“euthyroid GO”), while the occurrence of GO in patients with autoimmune Hashimoto’s thyroiditis is thought to be quite rare and has sporadically been reported. The late and abrupt occurrence of severe GO without hyperthyroidism in an 88-yr-old woman with primary myxedema due to atrophic thyroiditis must be considered as an exceptional event. In this patient, GO was combined with elevated titres of serum auto-antibodies directed against the TSH receptor, while serum levels of anti-thyroglobulin and thyroperoxidase antibodies were within the normal range or only occasionally slightly above the normal values.

Guidelines versus real life practice: the case of colonoscopy in acromegaly

PurposeThe aim of this study is to investigate guideline application and colonoscopy findings in real-life practice in acromegaly.MethodsWe conducted a retrospective observational non-interventional and cross-sectional analysis on 146 patients with acromegaly (ACRO) referred to our clinic. We evaluated colonoscopy data, focusing on the correlation between colonoscopy findings and hormonal/metabolic values.ResultsThe total number of colonoscopies performed in ACRO patients increased from 6 in the period 1990–1994 to 57 in the period 2010–2014. Colonoscopy procedures were performed according to guidelines in 25% of ACRO patients at diagnosis, 51% at follow-up and 11% globally (both at diagnosis and follow-up). Among the 146 ACRO patients, 68% were subjected to at least one colonoscopy and in 32% of the cases a polyp was detected during the procedure. The presence of polyps was significantly associated with mean levels of growth hormone (GH), insulin-like growth factor 1 (IGF-1), fasting glucose and insulin levels (p < 0.05). Polyps were detected in 48% of untreated patients and in 26% of patients under treatment for acromegaly (p = 0.04). The general risk of polyps and adenomatous polyps in ACRO patients was higher compared to the control population of Veneto Region, Italy (odds ratio 1.33 and 1.16, respectively). No cancerous polyps were detected in our analysis.ConclusionIn real-life practice, adherence to ACRO colonoscopy clinical guidelines was lower than expected. Among patients who underwent colonoscopy, the prevalence of colon polyps was higher for ACRO patients, suggesting the need for new strategies to ensure adherence to colonoscopy guidelines.