Identification of the diarrheogenic hormone associated with non-beta islet cell tumors of the pancreas

Primary Pancreatic Secretinoma: Further Evidence Supporting Secretin as a Diarrheogenic Hormone

OBJECTIVES

To document the existence of primary pancreatic secretinoma in patients with watery diarrhea syndrome (WDS) and achlorhydria and establish secretin as a diarrheogenic hormone.

BACKGROUND

Vasoactive intestinal peptide (VIP) has been widely accepted as the main mediator of WDS. However, in 1968, Zollinger et al reported 2 female patients with pancreatic neuroendocrine tumors, WDS, and achlorhydria. During surgery on the first, a 24-year-old patient, they noticed distended duodenum filled with fluid and a dilated gallbladder containing dilute bile with high bicarbonate concentration. After excision of the tumor, WDS ceased and gastric acid secretion returned. The second, a 47-year-old, patient's metastatic tumor extract given intravenously in dogs, produced significantly increased pancreatic and biliary fluid rich in bicarbonate. They suggested a secretin-like hormone of islet cell origin explains WDS and achlorhydria. These observations, however, predated radioimmunoassay, immunohistochemical staining, and other molecular studies.

METHODS

The first patient's tumor tissue was investigated for secretin and VIP. Using both immunohistochemistry and laser microdissection and pressure catapulting technique for RNA isolation and subsequent reverse transcription polymerase chain reaction, the expression levels of secretin, and VIP were measured.

RESULTS

Immunoreactive secretin and its mRNA were predominantly found in the tumor tissue whereas VIP and its mRNA were scarce.

CONCLUSIONS

The findings strongly support that the WDS and achlorhydria in this patient may have been caused by secretin as originally proposed in 1968 and that secretin may act as a diarrheogenic hormone.

Familial Multiple Endocrine Neoplasia

In 1903, Erdheim described the case of an acromegalic patient with a pituitary adenoma and three enlarged parathyroid glands. Fifty years later, Underdahl et al reported 8 patients with a syndrome of pituitary, parathyroid, and pancreatic islet adenomas. In 1954, Wermer found that the syndrome was transmitted as a dominant trait. In 1959, Hazard et al described medullary (solid) thyroid carcinoma (MTC), a tumor that later was found to be a component of two endocrine syndromes. The first of these described by Sipple in 1961 comprised pheochromocytoma, MTC, and parathyroid adenoma. The second, described by Williams et al in 1966, was the combination of mucosal neuromas, pheochromocytoma, and MTC. In 1968, Steiner et al introduced the term "multiple endocrine neoplasia" (MEN) to describe disorders featuring combinations of endocrine tumors; they designated the Wermer syndrome as MEN 1 and the Sipple syndrome as MEN 2. In 1974, Sizemore et al concluded that the MEN 2 category included two groups of patients with MTC and pheochromocytoma: one with parathyroid disease and a normal appearance (MEN 2A) and the other without parathyroid disease but with mucosal neuromas and mesodermal abnormalities (MEN 2B). Later, additional nonendocrine conditions (von Recklinghausen neurofibromatosis and von Hippel-Lindau disease) were found accompanying other more recently described familial MEN syndromes, indicating that these diseases are very complicated disorders.

Update on the diagnosis and treatment of rare neuroendocrine tumors

A growing knowledge and awareness of bizarre clinical presentations, the physiology of new peptides, and the more frequent use of radioimmunoassay techniques has led to the identification of more patients with glucagonomas, somatostatinomas, vipomas, and ectopic tumors. Definite clinical syndromes, though sometimes seemingly "silent," occur as a result of hypersecretion of newly identified hormones and neurotransmitters that act in endocrine, neurocrine, or paracrine fashion to alter normal metabolism of carbohydrates and electrolytes. Metabolically and clinically, glucagonomas are catabolic, somatostatinomas are inhibitory, and vipomas are diarrheogenic. The clinical syndromes can be differentiated from other, more common, endocrinopathies; the measurement of the plasma concentrations of the specific peptides is not only diagnostic, but prognostic. Specific pathologic confirmation of the functional potential of these tumors by immunocytochemical techniques is now possible. The goal of diagnosis is detection and tumor localization before metastases occur so that surgical excision may be curative. Objective clinical and humoral responses to chemotherapy for nonresectable or metastatic lesions can be expected in about 50 per cent of patients; specifically, dacarbazine (DTIC) is the agent of choice for glucagonomas, streptozotocin for somatostatinomas, and leukocyte interferon for vipomas.

Hyperparathyroidism presenting as the first lesion in multiple endocrine neoplasia type 1

In a study of 16 different families, 55 persons were considered to be affected by the syndrome of multiple endocrine neoplasia type 1 (MEN-1). Serum calcium measurements were available for all but six patients, long deceased, and hypercalcemia was invariably present. All but four of these patients have been subjected to surgery, and hyperparathyroidism was verified in each case. In all the patients studied, hyperparathyroidism was apparently the first manifestation of the MEN-1 syndrome. Pituitary tumors were detected in 23 patients, and there was evidence of pancreatic lesions in 32. Although either the pituitary or pancreatic manifestations dominated clinically in some patients, hyperparathyroidism was invariably present when sought. Measurement of serum calcium in asymptomatic relatives at risk for MEN-1 disclosed no case of hyperparathyroidism in children below the age of 18, whereas half of all screened persons between the ages of 18 and 30 were found to have hyperparathyroidism. In some, the serum calcium values were only marginally or even intermittently elevated. It is concluded that since hyperparathyroidism is apparently the first lesion in MEN-1, screening for this syndrome should primarily be directed toward the diagnosis of hyperparathyroidism. The temporal relationships suggest that hyperparathyroidism could be a prerequisite for the other types of endocrine neoplasms in the MEN-1 syndrome.

Watery diarrhea, hypokalemia and achlorhydria syndrome. Morphological and immunohistological study

A case of WDHA syndrome accompanied by a pancreatic tumor in a 44-year-old Japanese male is presented, the 6th case in Japan. Clinically, the patient suffered from unremitting watery diarrhea, hypokalemia and achlorhydria with marked anemia and jaundice. The patient died of emaciation, dehydration and bronchopenumonia, and an autopsy was performed. Autopsy examination revealed a hen's egg-sized tumor in the tail of the pancreas with metastases in liver, lungs and lymph nodes. In addition, bronchopneumonia and diabetic nephrosclerosis were present. Histologically, the tumor had the characteristics of an islet cell tumor, and histochemically the tumor cells were positive to Grimelius' stain which revealed non-B-islet cell features. Electron-microscopically, the tumor cells had electron dense round membrane-bounded granules resembling non-B-granules of pancreatic islet cells. With the immunoperoxidase procedure (PAP method), tumor cells nearly almost reacted to anti-vasoactive intestinal polypeptide (VIP) serum, which suggested that the tumor of the present case had the capability to produce VIP.

Multiple endocrine neoplasia syndromes

The multiple endocrine neoplasia (MEN) syndromes consist of three distinct disease entities. They have in common adenomatous, carcinomatous or hyperplastic involvement of a variety of endocrine glands, and an autosomal dominant inheritance. MEN I includes hyperparathyroidism, islet cell and pituitary tumors. The components of MEN IIa are hyperparathyroidism, medullary thyroid carcinoma and pheochromocytoma. MEN IIb includes multiple neuromas, medullary thyroid carcinoma and pheochromocytoma. Effective tests are available for the early detection of components of the syndromes in potentially affected patients. Screening can lead to therapeutic intervention before clinical sequelae ensue.

Mild chronic watery diarrhea-hypokalemia syndrome associated with pancreatic islet cell hyperplasia. Elevated plasma and tissue levels of gastric inhibitory polypeptide and successful management with nicotinic acid

A 46 year old woman is described who had a 13 half year history of watery diarrhea associated with hypokalemia and hypochlorhydria. The diarrhea was secretory as measured by triple lumen tube perfusion and was associated with an increased concentration of fasting plasma immunoreactive gastric inhibitory polypeptide (GIP) of 750 pg/ml which was stimulated to 4,000 pg/ml after a standard meal. The diarrhea decreased after partial pancreatectomy. Diffuse pancreatic islet cell hyperplasia was present and, although GIP was unmeasureable in the pancreas of normal subjects, it was at least 83 ng/g wet weight in this patient. Postoperatively, the patient's diarrhea responded dramatically to the oral administration of nicotinic acid.

Electron microscopy of neoplasms of pancreatic islet cells

Neoplasms of pancreatic islet cells that produce widely divergent clinical syndromes cannot be distinguished from one another by conventional microscopy. Differentiation among these tumors by electron microscopy is possible in some cases only. Coordinated clinical evaluation, histochemical and ultrastructural studies, and assay of serum and neoplastic tissue for various polypeptide hormones afford the best characterization of these neoplasms.

Vasoative intestinal peptide and the watery diarrhea syndrome

A sensitive and specific radioimmunoassay for the detection of vasoactive intestinal peptide has been used to study patients with the watery diarrhea syndrome. In eleven patients the syndrome was associated with tumors, and plasma levels of vasoactive intestinal peptide were elevated. VIP levels returned towards normal in five treated patients coincident with amelioration of symptoms. Normal values were obtained in patinets with chronic pancreatitis, sprue, medullary carcinoma, Zollinger-Ellison Syndrome and laxative abuse. In six other patients with indistinguishable syndrome and no findings of tumor at laparotomy and autopsy, vasoactive intestinal peptide levels were normal. The results suggest that VIP may be the causative agent in patients with the watery diarrhea syndrome and tumors, but that an indistinguishable syndrome exists for which VIP is not the cause.

Watery diarrhea syndrome. Two unusual cases and further evidence that VIP is a humoral mediator

Two unusual cases of the watery diarrhea syndrome are presented. In one patient an adrenal medullary tumor, a pheochromocytoma that produced vasoactive intestinal polypeptide (VIP) was excised with total relief of symptoms. The second patient a 65-year-old man with abrupt onset of massive watery diarrhea that led to acidosis and coma was symptomatically controlled for one year on 10 mg/day of prednisone. Elevated levels of VIP returned to normal after prednisone therapy was started. A benign islet cell tumor not localized by angiography was removed by distal pancreatic resection. Tissue levels of VIP were markedly elevated. VIP is a humoral mediator of the water diarrhea syndrome. Both benign and malignant pancreatic and extrapancreatic tumors may cause the watery diarrhea syndrome. Steroids may cause symptomatic relief of the diarrhea by lowering peptide levels to normal. The term watery diarrhea syndrome may be more accurate than the pancreatic cholera syndrome.

A pancreatic-polypeptide-producing tumour associated with the WDHA syndrome

A case with the clinical appearance of WDHA syndrome is described in which serum concentrations of the newly recognized hormonal principle pancreatic polypeptide (PP) were highly elevated, while plasma levels of vasoactive intestinal peptide were within the normal range. The symptoms of the patient seem to be derived from the high levels of circulating PP, as illustrated by an improvement after resection of liver metastases accompanied by a marked decrease of serum PP concentration. Streptozotocin treatment was without effect upon the watery diarrhoea, and PP levels also remained unchanged during medical treatment. The appearance of a PP-secreting tumour leading to a clinical WDHA syndrome widens the spectrum of hormone assays that have to be performed in these patients.

Diagnosis of chronic pancreatic disease

The diagnosis of pancreatic disease is difficult. The first step is clinical suspicion, based on the symptoms and signs. If pancreatic disease is suspected, investigation is necessary to prove this diagnosis. Investigation aims to answer two questions: a) is there pancreatic disease and b) if so, what type? The first question may be answered by demonstrating abnormal pancreatic function, using pancreatic function tests, whereas the second is answered by using techniques to demonstrate structural (anatomical) abnormalities of the pancreas. a) The methods to establish abnormal pancreatic function consist of 1. tests to demonstrate abnormal digestive capability, 2. tests to study pancreatic exocrine secretion, and 3. tests to study endocrine secretion. The tests of group 1 are: chemical fat balance study before and during enzyme replacement therapy, faecal nitrogen balance study, and the demonstration of either the malabsorption of vitamins A, D and K or the sequelae of their malabsorption (low serum calcium, high alkaline phosphatase, prolonged prothrombin time, etc.). Abnormal vitamin B12 absorption also may be present. 2. The tests designed to study pancreatic exocrine secretion are determination of the presence or absence of proteolytic enzymes in the stool, the secretion test, the pancreozymin stimulation test and the Lundh test. The serum amylase and lipase values are of little help in assessment of pancreatic function. 3. The tests to study endocrine function are the glucose tolerances test (which frequently gives abnormal results in pancreatic disease), and radioimmunoassays for insulin and gastrointestinal hormones (which may be increased in patients with functioning tumours of the islet cells). b) The techniques used to establish structural abnormalities of the pancreas are: duodenal cytology (during secretin tests), radiological techniques (abdominal survey films, barium meal, hypotonic duodenography, roentgenography of the biliary tract, barium enema, and angiography,) gastroscopy, duodensocopy, endoscopy and retrograde pancreatography, echography, scan and laparotomy. The relative value of these tests is discussed.

Immunofluorescent localization of secretin in pancreatic monolayer culture

Immunofluorescent cells to synthetic secretin were identified in monolayer culture of neonatal rat pancreas. No cross reaction of anti-secretin was observed with either glucagon, somatostatin or gastrin. The presence of cells containing secretin or a secretin-like peptide adds a new cell type to the three already characterized (insulin, glucagon and somatostatin containing cells) in monolayer culture.

[The Verner-Morrison syndrome. The clinical picture and pathologic anatomy]

The Verner-Morrison Syndrome is a clinically defined entity caused by an islet cell tumor of the pancreas. More than 60 cases have been described so long. The syndrome is characterized by diarrhea, hypokalemia and hypochlorhydria. In addition to a diabetic disposition, raised calcium levels and skin alterations may be present. The diagnosis is a clinical one. A pancreatic tumor should be searched for and removed. Morphologically a benign and a maligne islet cell tumor or a diffuse hyperplasia of the islets of Langerhans can be found. Until now identification of the tumor cells has not been possible. There seems no doubt that the tumor cells produce a peptide hormone. Secretin, gastric inhibitory polypeptide, vasoactive intestinal polypeptide and combinations of hormones are discussed. The results are contradictory. Theories concerning the formal and causal pathogenesis are only incomplete and unproved up to now.

Elevated plasma and tissue levels of vasoactive intestinal polypeptide in the watery-diarrhea syndrome due to pancreatic, bronchogenic and other tumors

The actions of the vasoactive intestinal polypeptide make it a potential candidate for mediating certain manifestations of the watery-diarrhea syndrome. Peptide levels were measured by radioimmunoassay in 25 controls and 30 patients with chronic watery diarrhea. Plasma levels were too low to measure (smaller 200 pg per milliliter) in 22 of the controls, averaging 79 plus or minus 64 pg per milliliter (S.D.). Levels were elevated in 26 of 28 plasma samples (5.1 plus or minus 2.5 ng per milliliter), and in each of 13 tissue extracts (5.1 plus or minus 10.9 mug per gram); in all, 28 patients had elevated levels in plasma or tissue or both. Thirteen patients had pancreatic islet-cell adenoma, four islet-cell hyperplasia, five bronchogenic carcinoma, and one each pheochromocytoma and ganglioneuroblastoma. The findings indicate that the peptide is a probable mediator of the watery-diarrhea syndrome, that the syndrome may result from a variety of non-pancreatic tumors, and that this or a related peptide may also be secreted by these tumors.

Pancreatic cholera (W.D.H.A. syndrome). Histochemical and ultrastructural studies

Results of light and electron-microscopic studies of primary pancreatic tumor and of metastasis in a new case of Pancreatic Cholera (P.C.) are reported. The primary tumor but not the metastases, contained unusual, large cystic glandular formations, lined both by pancreatic-duct- and small-intestine-like epithelia and closely connected with the endocrine proliferation. A part from a few D-cells, the endocrine tumoral cells could not be identified by histochemical stainings. Their ultrastructural pattern, with small secretory granules (diameter less than 300 nm) and numerous cytoplasmic bunches of filaments, was very similar to that of gastric and duodenal D1-cells. Normal duodenal D1-cells have been said to produce gastric inhibitory peptide, a substance structurally and biologically similar to the vasoactive intestinal peptide actually secreted by the tumor. The normal histological appearance of gastric, gallbladder, jejunal, ileal, right and left colonic mucosae is consistent with the responsibility of the tumoral secretion in the impairment of gut functions in P.C.

Pancreatic cholera: beneficial effects of treatment with streptozotocin

Two patients with pancreatic cholera and islet-cell carcinoma were treated with intra-arterial streptozotocin. Before therapy, they had stool volumes from 2 to 8 liters per day and required 200 to 800 mEq per day of supplemental potassium. After three to five doses of streptozotocin (1.5 per square meter), both stool volume and number and size of hepatic metastases decreased markedly. One patient has had normally formed stools for 12 months; the other had a 90 per cent reduction in stool volume for 13 months with additional therapy. Both patients' serum potassium returned to normal without need for supplementation. Jejunal adenylate cyclase activity was normal in both, and plasma vasoactive intestinal peptide was detectable in only one. After chemotherapy, these findings showed no consistent change. Pharmacologic studies suggest that arterial administration increased either tumor or hepatic extraction (or both) of streptozotocin by two times and decreased renal exposure to this nephrotoxic drug by one third.

Islet cell tumors of the pancreas and the alimentary tract

Functioning tumors of the pancreatic islets are now recognized as the source of clinical syndromes affecting the gastrointestinal tract which have a wide variety of catastrophic symptoms. Experiences with thirty-six cases suggest at least four separate diagnostic categories in the ulcerogenic tumor syndrome. These include: a typical history, gastric analysis, and roentgenographic findings with boderline fasting serum gastrin levels; ulcerogenic tumor with evidence of hyperparathyroidism; iatrogenic ulcerogenic syndrome associated with failure of a previous operation for duodenal ulcer; and the classic ulcerogenic syndrome associated with a fulminating ulcer diathesis or diarrhea and high serum gastrin levels. The problems presented at operation include: decisions to be make in the presence of a negative exploration; the finding of a solitary tumor in the wall of the duodenum; solitary pancreatic tumors particularly in the body and tail; ulcerogenic tumors in the very young; liver metastases in the elderly; and the wisdom of removing gross metastases in combination with total gastrectomy. The long-term survival in the ulcerogenic tumor syndrome approximated 50 per cent, with 40 per cent of those having proved malignancy living five years. Evidence of hyperparathyroidism is relatively common in association with both the ulcerogenic and the diarrheogenic tumor syndromes. The association may by a result of a congenital abnormality, metabolic alkalosis, or a direct effect of the islet cell tumor. Parathyroidectomy may be indicated when both the serum calcium and parathormone levels are elevated in the presence of borderline fasting gastrin levels. The latter may return to normal after parathyroidectomy. The evidence of hyperparathyroidism closely parallels the episodes of diarrhea in the diarrheogenic syndrome, and hyperparathyroidism may regress spontaneously after total removal of the pancreatic tumor. Just as routine calcium determinations made the diagnosis of hyperparathyroidism more commonplace, it is suggested that the gastrointestinal syndromes associated with islet cell tumor would receive wider recognition if radioimmunoassays for gastrin as well as secretin, and the other secretin-like polypeptides, were carried out routinely.

Studies on the potential role of secretin in the islet cell tumor diarrheogenic syndrome

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Gastro-duodenal hormones and bile flow

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Pancreatic islet cell tumour with watery diarrhoea and hypokalaemia

A further patient with watery diarrhoea and hypokalaemia in association with a non-beta islet cell tumour of the pancreas is reported. The mechanism by which fluid and electrolyte losses are produced is discussed and cases previously reported are reviewed.