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

Diffuse, Adult-Onset Nesidioblastosis/Non-Insulinoma Pancreatogenous Hypoglycemia Syndrome (NIPHS): Review of the Literature of a Rare Cause of Hyperinsulinemic Hypoglycemia

Differential diagnosis of hypoglycemia in the non-diabetic adult patient is complex and comprises various diseases, including endogenous hyperinsulinism caused by functional β-cell disorders. The latter is also designated as nesidioblastosis or non-insulinoma pancreatogenous hypoglycemia syndrome (NIPHS). Clinically, this rare disease presents with unspecific adrenergic and neuroglycopenic symptoms and is, therefore, often overlooked. A combination of careful clinical assessment, oral glucose tolerance testing, 72 h fasting, sectional and functional imaging, and invasive insulin measurements can lead to the correct diagnosis. Due to a lack of a pathophysiological understanding of the condition, conservative treatment options are limited and mostly ineffective. Therefore, nearly all patients currently undergo surgical resection of parts or the entire pancreas. Consequently, apart from faster diagnosis, more elaborate and less invasive treatment options are needed to relieve the patients from the dangerous and devastating symptoms. Based on a case of a 23-year-old man presenting with this disease in our department, we performed an extensive review of the medical literature dealing with this condition and herein presented a comprehensive discussion of this interesting disease, including all aspects from epidemiology to therapy.

Antidiarrheal Drug Therapy

INTRODUCTION

Acute diarrhea often runs a self-limited course and little by way of treatment is needed except for oral rehydration therapy. Chronic diarrhea poses a longer-term problem. If not treatable with specific therapy aimed at the underlying pathophysiology, chronic diarrhea often needs long-term symptomatic therapy.

PURPOSE OF REVIEW

This paper aims to examine the options for symptomatic, nonspecific treatment of diarrhea.

RECENT FINDINGS

The most frequently used therapies are opiate antidiarrheal drugs. These drugs are effective for a wide variety of diarrheal conditions and generally can be used safely if monitored closely. They work by slowing motility and allowing more time for absorption. They vary in potency and in addictive liability. In recent years, a variety of other drugs have been developed, which provide more targeted therapy that can mitigate diarrhea in specific situations. These drugs work on other regulatory pathways in the gut or on mucosal absorptive mechanisms. There is evidence for efficacy for both traditional and newer agents used for the symptomatic management of diarrhea. Opiates are used most often for this indication. Other agents may benefit individuals, but further research is needed to establish indications and best practices.

A simple matter of life and death-the trials of postnatal Beta-cell mass regulation

Pancreatic beta-cells, which secrete the hormone insulin, are the key arbiters of glucose homeostasis. Defective beta-cell numbers and/or function underlie essentially all major forms of diabetes and must be restored if diabetes is to be cured. Thus, the identification of the molecular regulators of beta-cell mass and a better understanding of the processes of beta-cell differentiation and proliferation may provide further insight for the development of new therapeutic targets for diabetes. This review will focus on the principal hormones and nutrients, as well as downstream signalling pathways regulating beta-cell mass in the adult. Furthermore, we will also address more recently appreciated regulators of beta-cell mass, such as microRNAs.

Gastrointestinal hormones and the regulation of β-cell mass

Type 2 diabetes occurs due to a relative deficit in β-cell mass or function. Glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), cholecystokinin (CCK), and gastrin are gastrointestinal hormones that are secreted in response to nutrient intake, regulating digestion, insulin secretion, satiety, and β-cell mass. In this review, we focus upon β-cell mass regulation. β-cell mass expands through β-cell proliferation and islet neogenesis; β-cell mass is lost via apoptosis. GLP-1 and GIP are well-studied gastrointestinal hormones and influence β-cell proliferation, apoptosis, and islet neogenesis. CCK regulates β-cell apoptosis and mitogenesis, and gastrin stimulates islet neogenesis. GLP-1 and GIP bind to G protein-coupled receptors and regulate β-cell mass via multiple signaling pathways. The protein kinase A pathway is central to this process because it directly regulates proliferative and anti-apoptotic genes and transactivates several signaling cascades, including Akt and mitogen-activated protein kinases. However, the signaling pathways downstream of G protein-coupled CCK receptors that influence β-cell mass remain unidentified. Gastrointestinal hormones integrate nutrient signals from the gut to the β-cell, regulating insulin secretion and β-cell mass adaptation.

Changes in acid-base balance and calcium metabolism after urinary diversion through ileal segments. II. Treatment with nicotinic acid

Investigations in animals have shown that nicotinic acid, an intestinal cyclic-AMP inhibitor, partially corrects the metabolic changes associated with urinary diversion through intestinal segments. Blood and serum chemistry were studied in patients before and 3 to 5 months after undergoing urinary diversion through ileal segments, both with and without nicotinic acid treatment. It was found that diverted patients had metabolic acidosis, an increased anion gap and increased levels of serum alkaline phosphatase; there were no significant changes in serum PTH and vitamin D levels, calcaemia and phosphoraemia. There was a tendency towards dehydration, hypernatraemia, hyperchloraemia and secondary hyperaldosteronism produced by ileal secretion of a hypotonic fluid. Nicotinic acid 3 g/day significantly reduced the chloraemia but did not correct the metabolic acidosis, although it reduced its severity, since blood pH decreased when treatment was suspended. Nicotinic acid cannot be recommended for routine use in the management of metabolic acidosis after urinary diversion, and patients with a marginal renal reserve should not be considered for trans-intestinal urinary diversion.

The WDHA syndrome: clinical and laboratory data on 28 Japanese cases

During the period between 1967 and 1983, there were 28 WDHA patients in Japan. Clinically, these patients were not very different from those reported in western countries, but we have been able to add a few observations as follows. First, the WDHA patients with pancreatic endocrine tumors and those with neuroblastic tumors were present in almost equal numbers. Second, fluctuating hypercalcemia was often observed in patients with this syndrome, but it was not observed in any watery diarrhea due to the other etiologies. Third, the WDHA patients who have multiple endocrine neoplasia (MEN) type 1 have multiple tumors in the pancreas, indicating that the patients with MEN should be managed in a different manner in regard to determining tumor location as well as applying surgical treatment. When various types of tumors were examined for VIP content, it was found that many tumors have the potential to produce VIP, and when VIP is produced in large amounts, plasma VIP levels become elevated, resulting in the WDHA syndrome.

Reduction of fluid-loss in cholera by nicotinic acid: a randomised controlled trial

A randomised controlled clinical trial was conducted to investigate the ability of nicotinic acid to reduce intestinal secretion in patients with severe cholera. Of the 62 adults investigated, 29 received either 1 or 2 g of nicotinic acid given orally in divided doses and 33 served as controls. Patients who received the 2 g dose had less fluid loss than did their controls during the first (p less than 0.01) and second (p less than 0.05) 8 h post-treatment periods. During the third and fourth 8 h periods, the rates were lower in the treatment groups, but not significantly so. The drug-specific stool reduction was 31%-47% during the first 16 h. Patients receiving 1 g consistently had lower rates of purging than had their controls during each 8 h observation period, but the differences were not significant. The effect of the 2 g dose was significantly better than that with the 1 g dose. The peak inhibition occurred 8-16 h after start of therapy. The drug was well tolerated, the only side-effect being transient flushing of the body in 1 patient.

Clinical aspects of GIP secretion

The gastric inhibitory polypeptide (GIP) is the main hormone of the incretin type acting on the entero-insular axis. It is released after fat, glucose or meal ingestion. The variations of this secretion are described in obesity and in some pancreatic and gastrointestinal diseases: it is increased in maturity onset diabetes mellitus, obesity or duodenal ulcer, variable according to the food taken and the severity of the pancreatic lesion in chronic pancreatitis and cystic fibrosis, normal in insulinoma and decreased in celiac disease. The impaired absorption of the food-stuffs and the defective feed-back regulation of GIP secretion by insulin are the major causes of these variations. To a lesser degree, gastric acid secretion, gastric emptying and vagal control may also influence GIP secretion.

GIP-like immunoreactivity in glucagon cells. Interactions between GIP and glucagon on insulin release

In the present study the cellular and subcellular distribution of immunoreactive glucagon and GIP (gastric inhibitory polypeptide) were studied in the mouse. Furthermore, the effects of pure GIP and glucagon on basal and stimulated insulin secretion were investigated. Immunohistochemistry revealed that immunoreactive GIP occurred in the pancreatic glucagon cells and in endocrine cells, also displaying glucagon immunoreactivity, scattered along the small and large intestines. Electron immunocytochemistry revealed that the GIP-like material and glucagon coexisted in the secretory granules of the pancreatic glucagon cells. Pure porcine GIP and glucagon both stimulated basal insulin release. When equipotent doses of the peptides were given together, the two peptides antagonized each other's effect. Both peptides potentiated glucose- and carbachol-induced insulin release. When equipotent doses of the two peptides were given together prior to the administration of each of these secretagogues their effects on insulin release were additive.