Cholera Syndrome Research Articles

Cholera and Pancreatic Cholera: Is VIP the Common Pathophysiologic Factor?

Background: Cholera remains a major global health problem, causing high output diarrhea leading to severe dehydration and shock in developing countries. We aimed to determine whether vasoactive intestinal polypeptide (VIP), the mediator of pancreatic cholera syndrome, has a role in the pathophysiology of human cholera. Methods: We conducted a prospective observational study of cholera cases hospitalized with severe dehydration. Plasma and stool water levels of VIP were measured just after admission, after complete rehydration (3–4 h), at 24 h post-rehydration and at discharge after diarrhea ceased. Results: In total, 23 cholera patients were examined between January and August 2018. The geometric mean of stool VIP (sVIP) and plasma VIP (pVIP) on admission were 207.67 and 8.34 pmol/L, respectively. pVIP values were all within the normal range (</= 30 pcmol/L); however, sVIP levels were very high at all timepoints, though less so just after rehydration. In multivariable GEE models, after adjustment for covariates, sVIP levels were significantly associated with duration of hospitalization (p = 0.026), total stool volume (p = 0.023) as well as stool output in the first 24 h (p = 0.013). Conclusions: The data suggest that VIP, which is released by intestinal nerves, may play an important role in human choleragenesis, and inhibitors of intestinal VIP merit testing for potential therapeutic benefits.

Impairment of oxidative burst in porcine neutrophils induced by pseudorabies virus.

Industrial swine production is affected by several serious viral diseases, such as pseudorabies, hog cholera, porcine reproductive and respiratory syndrome, which are frequently complicated with the increased incidence of bacterial complications such as Actinobacillus pleuropneumoniae (APP). This clinical observation is suggestive of a virus-bacteria synergism on the pathogenesis. One hypothesis is that viruses induce polymorphonuclear cell (PMNs, primarily neutrophils) dysfunction resulting in defective antibacterial resistance. The purpose of this study was to use the pseudorabies virus (PrV) as a model to explore the possibility of virus-induced PMN dysfunctions in pigs. The goals were to evaluate, in ex vivo settings, the oxidative burst (OB) function of pig PMNs, and to evaluate whether PrV could affect these responses to APP. We found that PrV served as a mild OB stimulant (2-fold) to pig PMNs, which also launched a significant burst to phorbol 12-myristate 13-diacetate (PMA; 61-fold), to non-opsonized, heat-killed and formaldehyde-fixed APP (8-fold), and to normal pig serum-opsonized APP (34-fold). Interestingly, the PMA-induced OB could be reduced 50-70% by preincubating PMNs with PrV, and the critical target was not likely the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase itself. Inactivated PrV was as efficient as viable PrV at exerting the inhibitory effect. On the other hand, PrV exerted a primarily additive effect on APP-induced OB, when the cytotoxic effect of APP on PMNs was avoided. The current finding suggests the possibility that activated PMNs are susceptible to PrV-induced dysfunction, and that the PrV-APP synergism may require upstream stimuli of PMNs to be initiated.

Clinical use of the long acting somatostatin analogue octreotide in pediatrics

Preliminary data of the use of the long-acting somatostatin analog octreotide (Sandostatin) in pediatrics are reported. In nesidioblastosis and other hyperinsulinemic conditions, timely treatment with octreotide can protect cerebral function and may reduce mortality. The acute use of octreotide produces prompt elevation of blood glucose, even in patients who fail to respond to diazoxide. In addition, it may be possible to avoid the need for partial or subtotal pancreatectomy by the long-term use of octreotide. As in adults, octreotide should find a place in the symptomatic treatment of secretory diarrhea, notably the watery diarrhea hypokalemia-achlorhydria complex and pancreatic cholera syndrome. Octreotide has been shown to be effective in the treatment of familial tall stature by reducing height velocity and final height. Responses to octreotide therapy vary and the individual responsiveness must be extensively studied.

Pancreatic cholera syndrome due to a vasoactive intestinal polypeptide-producing tumor: Further insights into the pathophysiology

This case report describes a patient with pancreatic cholera caused by a vasoactive intestinal polypeptide-producing pancreatic tumor. The case presents several unusual characteristics of this disease. The primary tumor was a mucinous adenocarcinoma of the pancreas. The serum vasoactive intestinal polypeptide level of 2400 pmol/L is the highest reported. At this vasoactive intestinal polypeptide level, the somatostatin analogue SMS 201-995 at doses up to 2 mg/24 h did not control the 21 L/24 h stool output. Fecal incontinence due to a manometrically documented hypotonic internal anal sphincter occurred. Using surgically created stomas, the segmental gastrointestinal fluid and sodium losses were shown to be greatest from the jejunum, whereas potassium losses from the colon and small intestine were equal. The cellular mechanism for the small intestinal potassium secretion is not known.

Cardiovascular effects of vasoactive intestinal peptide in healthy subjects

Hypotension and flushing are occasionally observed in patients with pancreatic cholera syndrome. Similar effects are produced when vasoactive intestinal polypeptide (VIP) is administered to healthy subjects. To characterize further these responses, serial measurements of heart rate, blood pressure, cardiac output and forearm blood flow were made in 6 healthy subjects during constant VIP infusion (400 pmol/kg/hr for 100 minutes). VIP infusion caused sustained vasodilatation and decreased total peripheral resistance and mean arterial pressure by 30 and 12%, respectively. Forearm resistance decreased by 65%. The effects on cardiac output and stroke volume were biphasic. During the early phase of VIP infusion (0 to 70 minutes), heart rate and cardiac output increased with only minor changes in stroke volume. Later (71 to 100 minutes) the tachycardia persisted, but cardiac output decreased toward control levels due to decreased stroke volume. Echocardiograms during the infusion demonstrated increased left ventricular contractility as defined by the relation between end-systolic wall stress and shortening fraction. These data document potent vasodilatory and inotropic actions of VIP. It is likely that intravascular volume losses from increased intestinal secretion account for the decreased stroke volume seen late in the VIP infusion period and immediately thereafter. The tachycardia appears to be an appropriate compensatory mechanism to maintain blood pressure in the presence of vasodilatation and loss of intervascular volume. These observations provide an explanation for the cardiovascular findings in patients with sudden release of VIP from tumors.

SUCCESSFUL TREATMENT OF THERAPY-RESISTANT PANCREATIC CHOLERA WITH HUMAN LEUCOCYTE INTERFERON

The pancreatic cholera syndrome is a serious and potentially fatal disease found in patients with endocrine pancreatic tumours and ganglioneuromas. Two patients with therapy-resistant pancreatic cholera syndrome were successfully treated with human leucocyte interferon given intramuscularly in a dose of 3 × 10 6-6× 10 6 IU per day. This produced a reduction in stool volume and plasma vasoactive intestinal polypeptide (VIP) within 3-5 days of the start of treat ment. Tumour mass decreased in one of the patients after 3 months of treatment but some tumour tissue remained after 15 months' observation, although circulating concentrations of VIP are normal. The mechanisms of action of interferon are not known but a direct inhibition of tumour-cell hormone production and perhaps of tumour-cell proliferation might account for the rapid clinical response.

VIP and the Pancreatic Cholera Syndrome

VIP and the Pancreatic Cholera Syndrome

Effect of somatostatin infusion on VIP-induced transport changes in the human jejunum

This study was designed to elucidate the mechanism by which somatostatin administration ameliorates or abolishes diarrhea in pancreatic cholera syndrome (PCS). Absorption (or secretion) of water and electrolytes was measured in 30-cm segments of jejunum of 18 healthy volunteers in whom PCS was mimicked by intravenous infusion of VIP. Using the triple-lumen tube technique, the intestine was perfused with a plasma-like electrolyte solution while administering intravenous saline (control), VIP (400 pmol/kg/hr), somatostatin (5000 pmol/kg/hr), or VIP plus somatostatin. VIP infusion abolished water and electrolyte absorption and somtostatin had no effect on these VIP-induced transport changes regardless of whether somatostatin infusion was started before or after VIP infusion. Somatostatin infusion had no effect on VIP plasma concentration when elevated by intravenous VIP infusion (control: 10±1 pmol/l ; during VIP infusion: 108±6). In a patient with pancreatic cholera syndrome identical perfusion experiments showed jejunal water secretion (93 ml/30 cm/hr) which changed to absorption (65 ml/30 cm/hr) when somatostatin was infused (5000 pmol/kg/hr). Plasma VIP concentration fell from 145 to 74 pmol/l (normal<50) during somatostatin infusion. Stool weight fell from 3722 g to 819 g per 24 hours when somatostatin was given at a dose of 2500 pmol/kg/hr for two days. Our observations in healthy subjects show that somatostatin has no effect on intestinal transport at the mucosal level when circulating VIP concentration is elevated. The findings in the patient with pancreatic cholera syndrome indicate that the effect of somatostatin on secretion (and diarrhea) is due to a decrease in circulating levels of VIP presumably due to reduced release of VIP from a tumor.

Production of Secretory Diarrhea by Intravenous Infusion of Vasoactive Intestinal Polypeptide

We attempted to reproduce the diarrhea of pancreatic cholera syndrome with prolonged (10-hour) administration of vasoactive intestinal polypeptide (VIP) in five healthy nonfasting subjects. The polypeptide was given as a continuous intravenous infusion at a rate of 400 pmol per kilogram of body weight per hour. By two hours the plasma VIP concentration had risen from a normal basal value of 15.3 +/- 0.2 (mean +/- S.E.M.) to 129 +/- 40 pmol per liter--within the range found in patients with pancreatic cholera syndrome. In each subject profuse watery diarrhea developed within 4.3 +/- 0.8 hours (range, 2.0 to 6.3), and the mean stool weight at 10 hours was 2441 +/- 600 g (normal 24-hour stool weight, less than 200 to 250 g). The results of stool analysis were consistent with secretory diarrhea. Between the first and last stool, there were significant increases in fecal sodium and bicarbonate concentrations and in pH. The large fecal bicarbonate loss induced hyperchloremic metabolic acidosis, which is characteristic in patients with pancreatic cholera syndrome. Our study suggests that VIP is not merely a marker of pancreatic cholera, but is the mediator of watery diarrhea in this syndrome.

Effect of VIP infusion on water and ion transport in the human jejunum

Infusion of vasoactive intestinal polypeptide (VIP) is known to cause intestinal secretion in animal models. The present study was designed to answer the question whether VIP has a similar effect on the human intestine. Pure porcine VIP was administered by constant i.v. infusion to healthy subjects while their jejunum was perfused with a plasma-like electrolyte solution. At the lowest VIP infusion rate (100 pmol/kg/hr), plasma VIP levels rose two- to fourfold, and there was an increase in the transmucosal potential difference but no change in sodium chloride absorption. At higher VIP infusion rates (200 and 400 pmol/kg/hr), VIP plasma concentrations rose to levels commonly observed in patients with pancreatic cholera syndrome. At these levels VIP caused a dose-dependent decrease of water and sodium absorption. Chloride absorption changed to secretion, while bicarbonate movement remained completely unaffected. Chloride secretion was active, since it occurred against an electrical and chemical gradient. All changes induced by VIP were reversible after discontinuance of VIP infusion. Our observations suggest that elevated levels of circulating VIP are capable of affecting water and ion movement in the human jejunum. They lend support to the hypothesis that high levels of circulating VIP may be a mediator of secretory diarrhea in some patients with pancreatic cholera syndrome.

Chronic diarrhea of unknown origin

We studied 27 patients with severe chronic diarrhea for which extensive investigations carried out at other institutions had failed to reveal a diagnosis. They were studied by standard diagnostic methods as well as by careful fecal analysis and intestinal perfusion. If they were incontinent of feces, anal sphincter function tests were performed. Although many were suspected of having pancreatic cholera syndrome, this diagnosis could not be established in a single patient. The most common diagnosis that could be established was surreptitious ingestion of drugs (laxatives in 7 patients and diuretics in 2). Other specific diagnoses included ulcerative colitis in 2 patients, allergy to beef in 1, and bacterial over-growth of the small intestine in 1. Thus, we were able to establish a specific diagnosis in 13 patients. Of the remaining 14 patients, 8 had findings suggestive of irritable bowel syndrome, and 2 others had anal sphincter dysfunction as the major cause of their disability. The other 4 undiagnosed patients had severe secretory (3 patients) or osmotic (1 patient) diarrhea. Follow-up interviews at 6 mo-6 yr failed to reveal evidence of a cause for diarrhea that had been overlooked during our studies. The diagnostic approach to patients with unexplained diarrhea is discussed. The importance of a search for surreptitious drug ingestion and accurate measurement of bowel movement frequency and stool weight is emphasized.

Hormone-Mediated Watery Diarrhea in a Family with Multiple Endocrine Neoplasms

A father and son each presented with severe watery diarrhea. The son was found to have a pancreatic islet-cell tumor associated with the pancreatic cholera syndrome, as well as a parathyroid adenoma. The father was found to have multiple islet-cell adenomas and the Zollinger-Ellison syndrome. Pancreatic tumor tissue from each patient contained detectable gastrin and vasoactive intestinal peptide; however, a much higher gastrin concentration was found in the tumor tissue from the father and a much higher vasoactive intestinal peptide content in the tumor tissue from the son. Thus, watery diarrhea may be mediated by different hormones in families having multiple endocrine neoplasia; the precise cause of the diarrheal syndrome should be defined to ensure the proper therapy.

Gastrointestinal Hormones in Clinical Disease: Recent Developments

With the advent of radioimmunoassay and immunocytochemical methods, the peptides of the gastrointestinal tract have been identified and measured. Gastrinoma and insulinoma syndromes have been wall characterized. The pancreatic cholera syndrome and some of the evidence that the major manifestations of this disease may be mediated by vasoactive intestinal peptide have been re-examined. Pancreatic polypeptide seems to be an ideal peptide for study of vagal-cholinergic mechanisms that regulate hormone release; it also appears to be a tumor marker for several types of pancreatic endocrine tumors, particularly those of pancreatic cholera. Secretin and cholecystokinin are important regulators of pancreatic exocrine secretion and have been used to test pancreatic function, but there is little evidence that they account for clinical disease. Glucagon-secreting tumors produce a clinical syndrome of diabetes mellitus and distinctive skin lesions, which can be cured by tumor resection. Hormone-secreting tumors may provide insight into normal gut physiology.

Watery Diarrhea Syndrome

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.

Intractable diarrhea

Small-intestinal perfusion studies with a triple-lumen tube were performed in the jejunum and ileum of 11 patients with a presumptive diagnosis of pancreatic cholera syndrome (PCS). Ultimately PCS was proven to be present in only 3 patients, whereas 6 were discovered to be taking either laxatives or diuretics surreptitiously. In 2 of the 11 patients the cause of the diarrhea could not be determined. In PCS the major abnormality which we observed was that the jejunal mucosa secreted rather than absorbed when perfused with a plasma-like solution. By contrast, the ileum of the PCS patients absorbed a plasma-like solution in a normal fashion; however, one patient failed to absorb sodium and chloride when a solution with low (50 mM) sodium chloride concentration was perfused in the ileum. The volume of endogenous fluid was high in both the jejunum and ileum, presumably because of proximal small-intestinal secretion. Glucose stimulated sodium movement in an absorptive direction in each patient. Studies were repeated in one PCS patient after tumor removal, and his intestinal absorption of water and electrolytes was normal. Patients with diarrhea due to surreptitious ingestion of laxatives and diuretics showed normal absorption in the jejunum and ileum. This study shows that proximal small-bowel secretion was the major cause for diarrhea in our 3 patients with PCS. This cannot be a consequence of diarrhea per se since it was not found in patients with long-standing diarrhea due to surrepitious drug ingestion. Small-intestinal perfusion studies may be helpful in the diagnosis and management of selected cases of severe chronic diarrhea. On the other hand, measurement of plasma VIP concentration, especially by methods currently used in the United States, is of little use and may be misleading.

VIP and WDHA

Watery diarrhea with hypokalemia and achlorhydria (WDHA) often complicates the clinical course of nonbetacell adenomas of the pancreas and occasionally of other hormone-secreting tumors. This serious and frequently fatal complication is sometimes referred to as pancreatic cholera or Verner-Morrison syndrome. 1 Neither the eponymic nor the descriptive term, however, provides clues to the hormone or hormones responsible for the increased intestinal secretion of fluid and electrolytes and for other metabolic derangements—achlorhydria, hypercalcemia, hyperglycemia—associated with WDHA. Barbezat and Grossman 2 suggested that gastrin and glucagon are the responsible hormones. Sanzenbacher and his associates 3 sought to incriminate secretin or secretin-like substances. Elias et al 4 reported a patient in whom gastrininhibitory-peptide appeared to be the culprit. None of these hypotheses, however, gained much credence. More substantial is the evidence implicating VIP, the vasoactive intestinal polypeptide that was discovered and purified by Said and Mutt 5 in 1970. This polypeptide, which is

Vasoactive intestinal peptide stimulation of adenylate cyclase and active electrolyte secretion in intestinal mucosa.

Vasoactive intestinal peptide (VIP), originally isolated from hog small intestinal mucosa, has been shown to cause small intestinal secretion. More recently, this peptide has been identified in the plasma and tumors of patients with the so-called "pancreatic cholera" syndrome. In order to explore the possible role of VIP in the pathogenesis of this syndrome, we examined the effects of this peptide and other hormones on the cyclic AMP levels, adenylate cyclase activity, and ion transport in in vitro preparations of ileal mucosa. In rabbit ileal mucosa, VIP (20 mug/ml) caused a prompt fivefold increase in cyclic AMP level, whereas nine other hormones, which have been postulated to cause intestinal secretion, failed to exert such an effect. Pentagastrin and glucagon also failed to increase cyclic AMP levels in canine ileal mucosa. An increase in mucosal cyclic AMP levels was observed at a VIP concentration of 0.1 mug/ml and appeared to be nearly maximal at 2.0 mug/ml. VIP (100 mug/ml) stimulated adenylate cyclase activity in a membrane preparation from rabbit ileal mucosa. Secretin (6.0 x 10(-5) M) failed to do so. When added to the serosal side of isolated rabbit ileal mucosa clamped in an Ussing chamber, VIP (2 mug/ml) increased short-circuit current (SCC) and caused net secretion of both Cl and Na. Net Cl secretion exceeded net Na secretion. These effects of VIP on mucosal cyclic AMP metabolism and ion transport are similar to those observed with cholera enterotoxin and certain prostaglandins. VIP was also tested with normal human ileal mucosa. At a concentration of 2 mug/ml it caused a fivefold increase in cyclic AMP level and an increase in SCC of the same magnitude as that caused by 5 mM theophylline. Addition of a second 2-mug/ml dose of VIP and addition of theophylline after VIP produced no further change in SCC. We conclude the VIP stimulates adenylate cyclase and active ion secretion in both rabbit and human ileal mucosa. This may be related to the pathogenesis of diarrhea in patients with the pancreatic cholera syndrome.

Studies of gastrointestinal viral flora of cholera patients.

Virus isolation studies on rectal swab specimens of cholera patients were carried out in tissue cultures during the Bangkok, Thailand cholera epidemic of 1958 and 1959. An adenovirus or enterovirus was isolated from 6 of 44 patients with proven cholera. It was concluded that viruses which can be isolated in monkey kidney and HeLa cell tissue cultures were not involved in the cholera syndrome.