Pancreatic acellular matrix supports islet survival and function in a synthetic tubular device: in vitro and in vivo studies.

Increasing pancreatic islet survival and function is a starting point for obtaining a valuable bioartificial pancreas for the treatment of type 1 diabetes. In this context, decellularized matrices, obtained after the removal of tissue cellular part, are known to support in vitro adhesion, growth, and function of several cell types. We demonstrate that a homologous acellular pancreatic matrix is a suitable scaffold for rat islet cultures maintaining their long-term viability and function. Islets adhered to the pancreatic matrix showed a constant glucose-induced insulin release during long-term in vitro incubation, while islets cultured without a matrix or on the liver matrix showed a progressive reduction. In order to obtain implantable devices, acellular matrix/islet cultures were entrapped into poly(vinyl alcohol) (PVA)/ poly(ethylene glycol) (PEG) tubes obtained by the freezing/thawing procedure. Under this condition, an in vitro constant insulin release was detected. The devices were then implanted into diabetic rats where reduced insulin requirement was noted suggesting insulin secretory activity of islets contained in the device. Indeed, immunofluorescence confirmed the presence of insulin- and glucagon-producing cells into the explanted devices. These data show that PVA/PEG semi-permeable membrane can obtain devices that restore, at least in part, insulin secretion.

Middle cerebral artery occlusion 25 years after cranial radiation therapy in acromegaly: a case report.

We report a case of ischemic stroke in a 43 year-old woman with no traditional cardiovascular risk factors and a history of cranial surgery and cranial radiation therapy (CRT) for a GH-secreting pituitary macroadenoma. The neurological work-up on this patient disclosed several cerebral ischemic lesions and demonstrated the occlusion of the right middle cerebral artery together with the narrowing of the right carotid artery; post-radiation brain damage was also visible by nuclear magnetic resonance. We postulate the existence in this patient of a radiation-induced vascular damage, which is a well recognized process thoroughly described in in vitro studies. We remark that life-long follow-up of acromegalic patients receiving CRT is essential so that early diagnosis of radiation-induced vascular injury can be made.

Autoimmune diabetes mellitus, Hodgkin's disease and Graves' ophthalmopathy in a patient with 8.1 ancestral haplotype.

In this report, we describe the case of a 43-year-old woman affected by type 1 diabetes mellitus diagnosed 8 years before, who developed Graves' disease 2 years after chemotherapy and mantle radiotherapy treatment for Hodgkin's disease. Bilateral Graves' ophthalmopathy appeared four months before our observations. Intravenous methyl-prednisolone therapy was started, but was interrupted due to severe metabolic failure. Autoantibodies (anti-islet cells, anti-thyroid, thyroid-stimulating, non-organ-specific) were positive. Since the clinical picture suggested a genetic immunological ground predisposing to autoimmunity, we evaluated her HLA haplotype. Genomic typing of the patient permitted identification of the 8.1 ancestral haplotype, a Caucasoid haplotype unique in its association with many immunopathological diseases. Moreover, we also observed a haplotype unusual in Caucasians, trans DRB1*1101, DQA1*0103, DQB1*0603. To our knowledge, HLA-related genetic risk of developing thyroid autoimmunity after neck irradiation has never been studied. Although we cannot confirm a direct association between the 8.1 ancestral haplotype or DRB1*1101, DQA1*0103, DQB1*0603 and the diseases described, we suggest considering immunological parameters and HLA typing in candidate patients for mantle radiation therapy for Hodgkin's disease or other tumors. HLA haplotype determination could be useful in identifying the patients at raised risk of developing autoimmune diseases after irradiation, thus permitting a more appropriate follow-up schedule.

Effects of a somatostatin analogue in occult gastrointestinal bleeding: a case report.

We describe the case of a patient with obscure gastrointestinal bleeding and anaemia, who required repeated transfusions for about 1 year. Because of the absence of a certain diagnosis and of a surgical approach indication, we established long-acting octreotide therapy, obtaining clinical stabilisation and interruption of the transfusional need. Withdrawal of long-acting somatostatin analogue therapy was associated with renewal of bleeding that was again successfully stopped by continuous i.v. somatostatin administration followed by re-establishment of the long-acting octreotide therapy. We suggested, in absence of surgical indications and when only palliative therapies are available, a therapeutic approach with long-term SMS analogues in patients with lower digestive bleeding of a known or unknown source.

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.

Effects of some vanadyl coordination compounds on the in vitro insulin release from rat pancreatic islets.

Many lines of evidence indicate that vanadium inorganic salts possess insulin-mimetic and insulinotropic properties. However, they are poorly absorbed, so high oral doses are required to achieve effective plasma concentrations with possible undesirable toxic side-effects ensuing. Various organically-chelated vanadium compounds have been synthesized that are more potent than inorganic vanadium salts in their insulin-like effects due to their greater bioavailability. Unfortunately, little is known about the possible insulin secretagogue action of organic vanadyl coordination compounds. Hence, we investigated the effect of [VO(metformin)2]H2O, [VO(salicylidene-ethylenedimmine)2] and [VO(pyrrolidine-N-dithiocarbamate)2](VODTC) on insulin release from isolated rat pancreatic islets, and compared it to that of vanadyl sulfate (VOSO4). Of the three coordination compounds, only VODTC was found to exert insulin secretagogue action. VODTC, within concentrations ranging from 0.1 to 1.0 mM, enhanced both basal and glucose (11 mM)-stimulated insulin release. The effect involves calcium channels, since it was not appreciable in Ca2+-free medium. The stimulating action of VODTC required the presence of the whole metal-chelator complex inasmuch as the chelator DTC alone was ineffective. VOSO4 was unable to bring about any significant rise in insulin release from isolated islets. Taken together, our findings indicate that VODTC may be considered a potential elective pharmaceutical tool in the therapy of diabetes, especially of type 2, through its concomitant stimulatory effect on insulin secretion and insulin-mimetic action.

[New perspectives in diagnosis and therapy of endocrine gastroenteropancreatic (GEP) tumors with somatostatin analogues]. / Nuove prospettive nella diagnosi e terapia dei tumori endocrini gastroenteropancreatici (GEP) con analoghi della somatostatina.

In the last decade important progresses have been obtained in the diagnosis and therapy of endocrine gastroenteropancreatic (GEP) tumors, mainly derived from the somatostatin receptors characterization and the introduction of long acting somatostatin analogues. Receptorial scintigraphy with radio-labeled analogues (Octreoscan) is the first choice investigation for staging and follow-up of endocrine GEP tumors, thanks to the high sensitivity in revealing the primary tumor and metastases, and for its capability to reveal lesions that are not identified by other imaging methods. Moreover, somatostatin analogues uptake by tumors allow us to use radiopharmaceutical compounds for advanced disease treatment. Between the radio-labeled drugs until now studied, interesting results have been obtained by DOTA-lanreotide (MAURITIUS), DOTA0 Tyr3-octreotide (DOTATOC) and DOTA0 Tyr3-octreotate, bound to beta-emitting radio-isotope suitable for therapeutic use. In the field of the pharmacological therapy of GEP tumors, the clinical trials show that somatostatin analogues reduce the symptoms related to functionally active tumors and stabilize or slow tumor growth improving the patient quality of life. Although somatostatin analogues alone could not be able to cure GEP tumors, their early utilization in association with surgical debulking of primary tumor and metastases, embolization or chemoembolization, and interferon, chemotherapy and radio-metabolic therapy (mainly directed to the destruction of micrometastases), increases the possibility of a radical therapeutic intervention. The continuous evolution of pharmacological research provides always new analogues (octreotide LAR, lanreotide, vapreotide, BIM-23244, BN 81644, PTR-3173, BIM-23A387, SOM-230, etc.) with different pharmacokinetic and receptorial properties and acting with more effectiveness in the different individual clinical situations. In this context there have been recently introduced also the "chimeric" analogues. On the other hand, the widespread utilization of molecular biology and immunohistochemical methods can allow, in perspective, to better define the receptorial pattern of individual endocrine tumors, after their surgical removal. The necessity to integrate endocrinological, nuclear medicine, surgical, oncologic and laboratory competencies behaves a multidisciplinary approach based on the utilization of diagnostic-therapeutic protocols supplying comparable results. It does not appear unjustified to expect, in the future, a scenery of more "individual" and more effective therapies for patients affected by GEP tumours.

Relationship between blood pressure and glucose tolerance in acromegaly.

BACKGROUND: Hypertension represents a well-known risk factor for cardiovascular diseases. The pathogenesis of hypertension in acromegaly is commonly viewed as multifactorial, but the possible influence of metabolic disorders on blood pressure (BP) in affected patients is largely unknown. OBJECTIVE: The aim of the present study was to evaluate the impact of glucose metabolism abnormalities on BP values in a series of patients with active acromegaly. DESIGN: An open multicentre prospective study. PATIENTS: Sixty-eight patients with active disease, aged 47.5 +/- 11.7 years, have been studied. Thirty-nine had normal glucose tolerance (NGT), 16 impaired glucose tolerance (IGT) and 13 suffered from diabetes mellitus (DM). MEASUREMENTS: Mean clinical BP values were calculated as the mean of BP values obtained by sphygmomanometric measurement in three separate occasions and mean 24-h, diurnal and nocturnal systolic (SBP) and diastolic (DBP) values were obtained by 24-h ambulatory blood pressure monitoring (ABPM). RESULTS: Patient's age and the degree of glucose tolerance abnormalities were found to significantly and independently influence BP values. All clinical and ABPM SBP and DBP values significantly increased with age by linear regression (P < 0.02 for all BP values, 0.30 < or = R < or = 0.43), and the independent influence of this parameter on BP values was confirmed by mutivariate analysis. Similarly, the independent influence of glucose tolerance abnormalities on BP values was confirmed when introducing age as a covariable in a multivariate analysis, and patients with DM presented significantly higher clinical SBP and 24-h, diurnal and nocturnal SBP and DBP than patients with NGT (P < 0.02 for clinical SBP, P < 0.015 for all ABPM values, respectively). In addition, patients with DM showed significantly higher 24-h, diurnal and nocturnal DBP than those with IGT (P < 0.05 in all cases). In contrast, no significant difference was found between NGT and IGT patients. No significant influence of disease duration, BMI, GH, IGF-I, or fasting and 2-h post glucose load insulinaemia on BP values was observed. CONCLUSIONS: Abnormalities of glucose metabolism significantly contribute to increase systolic blood pressure and especially diastolic blood pressure in acromegalic patients. Careful control of blood pressure and of risk factors for developing systemic hypertension, with special reference to glucose tolerance, is mandatory to decrease cardiovascular morbidity and mortality in such patients.

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.

Morphologic study of microcirculation in acromegaly by capillaroscopy.

Although wide range investigations on the heart and great vessels have been reported in acromegaly, the field of microcirculation is still largely vacant. The nailfold is a window through which we can observe in vivo the vascular bed. This study investigates through nailfold capillaroscopy the morphology of cutaneous microcirculation in acromegaly in relationship with the usual hormonal parameters of disease activity. Twenty-five acromegalic patients and 26 normal subjects, age and sex matched, were studied. A subgroup of acromegalics (8 patients) was considered in stable remission, and the remaining 17 had active disease. Capillaroscopy was performed in each subject by in vivo computer aided stereomicroscopy (magnification, x400). The following morphological parameters were calculated: the number of tortuous loops, meandering capillaries, and capillaries per millimeter; avascular areas; visibility of subpapillary plexus; the capillary length; and intercapillary distance. We were unable to perform the exam in 4 of 25 patients because visibility was poor. The capillary number and length were significantly reduced in acromegalics compared to controls [8.9 +/- 1.5 vs. 10.3 +/- 1.2 no./mm (P = 0.0010) and 174 +/- 49 vs. 255 +/- 24 microm (P < 0.0001)]. Moreover, in acromegalics, the numbers of tortuous loops and meandering capillaries were significantly increased [19 +/- 8 vs. 13 +/- 5 (P = 0.0027) and 10 +/- 12 vs. 0.7 +/- 1.1 (P < 0.0001)]. The capillaroscopic alterations were still observed in a smaller group of 8 nondiabetic and nonhypertensive acromegalics. We found branch-like capillaries in 4 acromegalic patients, but not in the control group. Finally, we observed a meaningful different and ameliorated capillaroscopic morphology in acromegalic patients in stable remission compared to active disease patients as far as the total number (density) and meandering capillaries were concerned. In conclusion, our study shows that in acromegaly, morphological alterations also affect the peripheral microcirculation, which seems to be influenced by the activity of the disease. We believe that nailfold capillaroscopy may represent an additional useful tool in the follow-up of acromegalic patients.

Gender-dependent variability of signal-averaged electrocardiogram in acromegaly.

Ventricular late potentials are obtained by signal-averaged surface electrocardiography. Late potentials in normal subjects may be influenced by physiological elements such as gender, height and body mass index. Considering that growth hormone (GH) hypersecretion is able to markedly alter different anthropometric variables, we studied the relation between these elements and the late potentials of 22 acromegalic patients. Males registered higher absolute QRS duration and LAS40 (low-amplitude signal) and, on the opposite, lower RMS40 (root mean square) in comparison to females; QRS duration and LAS40 seem to depend, however, on the different anthropometric variables, since their normalization with height and lean body mass (LBM) abolishes gender-dependent differences. On the contrary, the persistence, among males, of lower RMS40 in respect to females even after normalization for height, LBM and insulin-like growth factor 1 values makes it likely that the latter ECG variable is independent of the anthropometric ones and from the disease's activity. Moreover, males appear to be more vulnerable to GH heart-harming activity.

The nature of life in the history of medical and philosophic thinking.

The vitalistic doctrine of Aristotle and Galen, in which the soul is an indissoluble part of the body, was undisputed throughout most of the Middle Ages. The first radical change came with Telesio, who developed philosophic naturalism in which the soul has a reality of its own, though it is connected to the body. The definitive change came with Descartes, who believed that all biologic phenomena can be explained by the laws of mechanics, and only man is distinguished by the possession of a soul. For the next 300 years, this mechanistic view would be challenged by a new vitalism, in which the 'vital force' has an existence in its own right.

Acromegalic cardiopathy: a left ventricular scintigraphic study.

In order to study "acromegalic cardiomyopathy", cardiac function was examined, using gated radionuclide ventriculography, in 18 acromegalic patients and 21 control subjects with no clinical evidence of cardiac involvement. In these acromegalic subjects, while the Ejection Fraction (EF) did not appear to be significantly different, the Peak Filling Rate (PFR) was reduced while the Time to Peak Filling Rate (TPFR) resulted significantly greater than in control subjects. These findings indicate that chronic growth hormone (GH) hypersecretion, as observed in acromegaly, deteriorate the cardiac ventricular relaxation (diastolic phase) while it has no influence on contractility (systolic phase).

Increased muscular phospholipase A2 activity in diabetic rats.

Anomalies in prostaglandin (PG) synthesis have been suggested in both experimental and human diabetes mellitus; increased levels of plasma and tissue eicosanoids has been recently reported by several investigators. One step in prostaglandin synthesis is the enzymatic hydrolysis of membrane phospholipids by Phospholipase A2 (PLA2). Nevertheless the alternative pathway involving Phospholipase C must be considered. An evaluation of PLA2 activity is therefore a useful method for studying prostaglandin synthesis in the peripheral target tissues of insulin activity. We studied PLA2 activity in normal and diabetic rat muscle. Streptozotocin-induced diabetic rats showed significantly higher muscular PLA2 activity when compared with controls (3.04 x 10(-2) +/- 0.50 x 10(-2) versus 1.34 x 10(-2) +/- 0.35 x 10(-2) arachidonic acid pMol.mg protein-1.min-1 (p less than 0.01). This effect was not observed in diabetic animals successfully treated with insulin (1.78 x 10(-2) +/- 0.5 x 10(-2) versus 1.34 x 10(-2) +/- 0.35 x 10(-2) arachidonic acid pMol.mg protein-1.min-1), and a significant correlation was found between blood glucose and muscular PLA2 activity (r = 0.42; p less than 0.05). Our results clearly show that in streptozotocin-induced diabetic rats muscular PLA2 activity is significantly higher. The relationship between blood glucose levels and muscular PLA2 activity and the decrease of PLA2 activity after insulin treatment suggest that these changes may be related to a defect in insulin effect.

A study on the hyperinsulinism of late pregnancy.

Much research has demonstrated that in late pregnancy glucose administration causes a marked increase of peripheral insulin levels. To ascertain whether this particular increase is due to increased insulin secretion and/or to reduced hepatic insulin removal, we measured blood glucose, plasma C-peptide and plasma insulin during OGTT in 7 nonpregnant women and in 20 nondiabetic women at third trimester of gestation and 60-90 days after delivery. The C-peptide/insulin molar ratio was calculated for all subjects. Data obtained showed that both plasma insulin and C-peptide response to oral glucose is considerably higher in women at third trimester of pregnancy as compared with that observed in the same subjects after delivery and in nonpregnant women. The basal (overnight fasting) C-peptide/insulin molar ratio did not differ significantly between pregnant and nonpregnant women. After the oral glucose load the molar ratio was sharply reduced in all groups of subjects, but the overall decrease in the pregnant women in the three hours following oral glucose was considerably greater than in postpartum and in nonpregnant women. The increased plasma C-peptide response clearly indicates that in pregnancy oral glucose-induced hyperinsulinism is caused by increased insulin release from pancreatic B-cells. Moreover, the marked overall decrease of the C-peptide/insulin molar ratio suggests, even if it does not definitely prove, that hyperinsulinism after glucose in late pregnancy may be a consequence not only of increased insulin secretion, but also of decreased hepatic extraction of insulin.