Giancarlo Biliotti

Peptide-containing innervation of the human intestinal mucosa

SummaryThe three-dimensional distribution of the peptide-containing invervation in the human intestinal mucosa was studied by fluorescence immunohistochemistry on whole-mount mucosal preparations. An extensive VIP-immunoreactive nerve supply was demonstrated at all levels, but was markedly increased in density in the distal intestine, where it formed a particularly rich network in close contact with the luminal epithelium. In contrast, substance P-containing nerve fibres formed a looser and evenly distributed innervation at all levels. The muscularis mucosae was richly supplied by VIP-and substance P-containing fibres. Met-enkephalin immunoreactivity was confined to a few scattered nerve bundles running in the muscularis mucosae and around the bottom of epithelial crypts.

Nesidioblastosis and islet cell changes related to endogenous hypergastrinemia.

SummaryThe endocrine pancreas from four hypergastrinemic patients with recurrent peptic ulceration has been studied by light and electron microscopy. Greatly increased numbers of ducts and centroacinar cells have been observed associated with a striking increase in the number of islets and endocrine cells scattered in the acinar tissue (nesidioblastosis). The islet cells scattered throughout the exocrine parenchyma are of all the known islet cell types, with a prevalence of B and especially A cells. Many islets, probably formed de novo, are of a considerable size, have irregular contours and are in close apposition to centroacinar cells and ducts. The degree of nesidioblastosis and islet hyperplasia does not seem to be related to the plasma gastrin levels.Cytological changes have also been found in the islet cells of the hypergastrinemic patients compared with controls. These changes mainly affect the B cells and consist of a striking decrease in the number of mature secretory granules associated with a fairly extended ergastoplasm and Golgi apparatus and with a relevant increase in the number of immature granules. In two of the four patients examined, who had more severe hypergastrinemia, cytological signs of enhanced secretion are also recognized in A cells. The features indicating hypersecretion of B and A cells seem to be related to the plasma gastrin levels.The above findings indicate that chronic endogenous hypergastrinemia promotes proliferation and differentiation of islet cells and stimulates the secretory function of B cells and, to a lesser extent, of A cells, thus providing evidence for a trophic and secretagogue action of gastrin on the endocrine pancreas.

Intramural distribution of immunoreactive vasoactive intestinal polypeptide (VIP), substance P, somatostatin and mammalian bombesin in the oesophago-gastro-pyloric region of the human gut

SummaryThe intramural distribution of vasoactive intestinal polypeptide (VIP), substance P, somatostatin and mammalian bombesin was studied in the oesophago-gastro-pyloric region of the human gut. At each of 21 sampling sites encompassing this entire area, the gut wall was separated into mucosa, submucosa and muscularis externa, and extracted for radioimmunoassay. VIP levels in the mucosa were very high in the proximal oesophagus (1231±174 pmol/g, mean±SEM) and showed varied, but generally decreasing concentrations towards the stomach, followed by a clear-cut increase across the pyloric canal (distal antrum: 73±16 pmol/g, proximal duodenum: 366±62 pmol/ g); consistent levels were found in submucosa and muscle (200–400 pmol/g) at most sites, the stomach again showing lower concentrations. By contrast, substance P was present in small amounts as far as the proximal stomach, but sharply increased across the pyloric canal, especially in mucosa and submucosa (distal antrum: 20±6.5 and 5.5±1.3 pmol/g; proximal duodenum: 62±8.5 and 34±11 pmol/g, respectively). Somatostatin concentrations were very low in the mucosa of the oesophagus and stepwise increased in the cardiac, mid-gastric and pyloric mucosa (cardia: 224±72 pmol/g; distal antrum: 513±152 pmol/g; proximal duodenum: 1013±113 pmol/g); concentrations in the submucosa and muscularis were generally low, with the exception of antrum and duodenum. Mammalian bombesin was comparatively well represented throughout the oesophageal muscularis (5–8 pmol/g), but most abundant in the stomach in all layers (oxyntic mucosa: 24±2.7 pmol/g; submucosa: 20±5.7 pmol/g; muscle: 28±5.0 pmol/g). In conclusion, a distinct differential distribution of the four peptides studied was revealed, indicating a diffuse, but highly differentiated peptide-containing innervation of the proximal human gut.

Pathologic Features and Long-term Results in Early Gastric Cancer: Report of 116 Cases 8–13 Years after Surgery

One hundred sixteen patients who underwent surgery for early gastric cancer (EGC) at Careggi General Hospital in Florence between 1987 and 1992 were studied with regard to clinicopathologic features, incidence, and recurrence of the disease. The overall 5-year cumulative survival rate was 87.5%, and the disease-specific 5-year survival rate was 88.2%. EGC was limited to the mucosa in 43 patients (37%), while it infiltrated the submucosa in 73 others (63%). At the time of surgery, 9.5% of patients were found to have lymph node metastasis, always concomitant with submucosal invasion. There was 1 postoperative death (0.8%); 16 patients (13.7%) died of tumor recurrence, and 20 (17.2%) died of unrelated causes. Analysis of recurrence showed an intestinal histotype in 13 patients (81.2%), submucosal infiltration in 14 patients (87.5%), a Pen-A growth pattern in 8 patients (50%), and lymph node involvement in 3 patients (18.7%). The Cox proportional hazard model indicated that age and depth of wall invasion were statistically significant. The best predictor of survival appears to be the depth of invasion within the gastric wall. The claim by several investigators that prognosis for EGC is also associated with the presence of lymph node involvement is not supported by the present study. The postoperative 5-year survival rate in node-negative patients was 88.8% compared to 81.8% in node-positive patients (p = 0.296).

Intramural distribution of Met5-enkephalin-Arg6-Gly7-Leu8 in sphincter regions of the human gut

The intramural distribution of Met5-enkephalin-Arg6-Gly7-Leu8 (MERGL) was studied in the oesophago-cardiac, pyloric, ileo-caecal and sigmoid-recto-anal regions of the human digestive tract. Serial samples encompassing each area were separated into mucosa, submucosa and muscularis externa and extracted for radioimmunoassay. Comparatively low levels of MERGL immunoreactivity were measured throughout the cardiac junction. Conversely, a remarkable peak of MERGL concentration was detected at the pyloric junction, in both submucosa and muscularis. A progressive decrease in tissue levels of the same peptide, most evident in the submucosa, was detected on the proximal side of the ileo-caecal region. In the distal sigmoid colon and rectum MERGL concentrations showed a rapid decline, down to very low levels in the anal canal. The results may suggest the involvement of an enkephalinergic mechanism in the control of the human pylorus.

Nesidioblastosis and intermediate cells in the pancreas of patients with hyperinsulinemic hypoglycemia

SummaryThe pancreases of three patients with hyperinsulinemic hypoglycemia were studied : one of these patients was a child born to a diabetic mother, the other two were adults with insulinomas. All the patients had nesidioblastosis, namely the presence of a number of pancreatic endocrine cells spread throughout the exocrine tissue singly or clustered in small groups. In the hypoglycemic child the endocrine cells scattered in the acinar tissue were mostly A cells, whereas in the patients with insulinomas both A and B cells were found with a similar frequency. Intermediate cells (acinar-islet cells) were found in all the cases. These findings suggest that nesidioblastosis and the de novo formation of intermediate cells are associated phenomena.Possible mechanisms for the genesis of the islet cell types spread throughout the exocrine parenchyma and of the intermediate cells are discussed and their possible clinical implications are suggested.

Morphological changes in the human endocrine pancreas induced by chronic excess of endogenous glucagon

SummaryThe non-tumoral endocrine pancreas from a patient with elevated plasma levels of glucagon due to a malignant glucagonoma was studied immunocytochemically, ultrastructurally and morphometrically. Compared with normal pancreatic islets from control subjects, those of the pancreas from the patient with a glucagonoma showed an almost complete disappearance of A cells, a decrease in immunoreactive insulin in B cells associated with cytological features indicating enhanced synthesis and secretion of this hormone, and an increase in immunoreactive somatostatin and pancreatic polypeptide (PP) accompanied by unusually high numbers of D and PP cells. In addition, numerous B cells were found outside the islets, either forming microislets or scattered in the exocrine tissue (nesidioblastosis). The possible mechanisms involved in determining the changes in the secretory activity of B cells and the alterations in the cell composition of the islets are discussed.

Immunocytochemical and ultrastructural abnormalities of islet tissue in patients with VIP-producing tumors of the pancreas.

Nontumoral endocrine pancreas from three patients with malignant vasoactive intestinal polypeptide (VIPhmas and the Verner-Morrison (watery diarrhea, hypokalemia, and hypoachlorhydria) syndrome was studied immunocytochemically, ultrastructurally, and morphometrically. Compared with normal islets from control subjects, those of the VI Poma-associated pancreas showed a decrease of immunoreactive insulin in B-cells associated with cyto-logical features indicative of enhanced insulin synthesis and secretion and an increase in the number of immunoreactive somatostatin- and pancreatic poly-peptide-containing cells, in the absence of ultrastructural signs of modified secretory activity. No substantial alterations of A-cells were observed. In addition, images of diffuse de novo formation of ducts and islet tissue were often found. Possible mechanisms involved in determining the above changes are discussed.

A Malignant Tumor of the Pancreas Producing Glucagonoma Syndrome: Immunocytochemistry and Ultrastructure of Liver Metastases and Comparison with the Primary Tumor

In this study, liver metastases from a patient with a pancreatic glucagonoma producing the syndrome have been investigated histologically, ultrastructurally, and immunocytochemically. A comparison has also been made between the metastases and the primary pancreatic tumor investigated in a parallel study. In the metastatic tissue, glucagon-, pancreatic polypeptide (PP)-, and somatostatin-containing cells were found together with a majority of cells without any immunoreactivity. Glucagon-positive cells were much more numerous than PP- and somatostatin-immunoreactive cells. As in the primary tumor, double immunogold staining of ultrathin sections demonstrated the coexistence of glucagon and PP immunoreactivities in most of the granulated cells, but PP immunolabeling was often faint, so that it probably could not be revealed by the PAP method in light microscopical sections. Such a finding, together with the histological and ultrastructural features, is consistent with an ontogenic and phylogenetic primitiveness of the metastatic cell population.

A malignant tumor of the pancreas producing glucagonoma syndrome: coexistence of glucagon and pancreatic polypeptide (PP) in the tumor cells

A malignant tumor of the pancreas producing the glucagonoma syndrome and associated with high plasma levels of glucagon and pancreatic polypeptide was studied histologically, ultrastructurally, and immunocytochemically. The histologic and ultrastructural features were closely similar to those of previously reported malignant glucagonomas. However, immunolabeling with specific antisera revealed that, in addition to cells having only glucagon- or only pancreatic polypeptide-immunoreactivity, other cells were also present, showing a co-existence of both peptides. These findings indicate that the tumor contains a cell population with a phenotype similar to that of intestinal L-cells rather than to pancreatic A-cells.