Intraluminal gastric pH in chronic pancreatitis

pH-taxis drives aerobic bacteria in duodenum to migrate into the pancreas with tumors

As oral or intestinal bacteria have been found in pancreatic cystic fluid and tumors, understanding bacterial migration from the duodenum into the pancreas via hepato-pancreatic duct is critical. Mathematical models of migration of aerobic bacteria from the duodenum to the pancreas with tumors were developed. Additionally, the bacterial distributions under the pH gradient and those under flow were measured in double-layer flow based microfluidic device and T-shaped cylinders. Migration of aerobic bacteria from the duodenum into pancreas is counteracted by bile and pancreatic juice flow but facilitated by pH-taxis from acidic duodenum fluid toward more favorable slightly alkaline pH in pancreatic juice. Additionally, the reduced flow velocity in cancer patients, due to compressed pancreatic duct by solid tumor, facilitates migration. Moreover, measured distribution of GFP E. coli under the pH gradient in a microfluidic device validated pH-tactic behaviors. Furthermore, Pseudomonas fluorescens in hydrochloride solution, but not in bicarbonate solution, migrated upstream against bicarbonate flow of > 20 μm/s, with an advancement at approximately 50 μm/s.

Role of the Immune System and the Circadian Rhythm in the Pathogenesis of Chronic Pancreatitis: Establishing a Personalized Signature for Improving the Effect of Immunotherapies for Chronic Pancreatitis

Pancreatitis, in both acute and chronic forms, poses a major therapeutic challenge and is associated with great morbidity and several complications. The nature of pancreatic injury in chronic pancreatitis (CP) and the wide range of causative processes that lead to CP have made effective therapy a true unmet need. Multiple physiological, genetic, environmental, and behavioral factors contribute to the development of CP. As a result, several fields of research are aimed at identifying and addressing the factors that contribute to pancreatic injury. In this article, we review the current understanding of the pathogenesis and natural history of CP. We focus on the autonomous nervous system, immune system, and role of a chronobiological therapeutic approach to alleviate symptoms and prevent or reverse pancreatic injury associated with CP. We aim to demonstrate that individualizing chronopharmacological treatments for CP is a promising direction for future treatment using immune, nervous, and circadian systems.

Circadian Genes as Therapeutic Targets in Pancreatic Cancer

Pancreatic cancer is one of the most lethal cancers worldwide due to its symptoms, early metastasis, and chemoresistance. Thus, the mechanisms contributing to pancreatic cancer progression require further exploration. Circadian rhythms are the daily oscillations of multiple biological processes regulated by an endogenous clock. Several evidences suggest that the circadian clock may play an important role in the cell cycle, cell proliferation and apoptosis. In addition, timing of chemotherapy or radiation treatment can influence the efficacy and toxicity treatment. Here, we revisit the studies on circadian clock as an emerging target for therapy in pancreatic cancer. We highlight those potential circadian genes regulators that are commonly affected in pancreatic cancer according to most recent reports.

Endoscopic and Conservative Management of Chronic Pancreatitis and Its Complications

Chronic pancreatitis is a progressive inflammatory disease of the pancreas potentially giving rise to several complications. For this reason, patients need long-term care and treatment by medical, interventional, and sometimes surgical measures. This article reviews current state-of-the-art strategies and guidelines for treating chronic pancreatitis with conventional and endoscopic measures.

The Pancreatic Duct Ligated (Mini)pig as a Model for Pancreatic Exocrine Insufficiency in Man

Modern therapy of pancreatic exocrine insufficiency (PEI) using pancreatic enzyme replacement therapy (PERT) has largely been very effective and has greatly helped in improving the nutritional status of patients with PEI and in increasing the life expectancy in cystic fibrosis. It is believed that the use of predictable large animal models could play an important role in assessing and developing new therapies. This article reviews the pancreatic duct ligated (adult) minipig as a chronic model of total PEI, with a detailed look at the influence of PEI and response to PERT on prececal compared to fecal digestibility, to directly investigate effects on protein and starch digestion and absorption. In addition, the piglet with PEI is reviewed as a model for PEI in young patients with the aim of further improving the therapy and nutritional status of young patients with cystic fibrosis.

Retrospective analysis to investigate the effect of concomitant use of gastric acid-suppressing drugs on the efficacy and safety of pancrelipase/pancreatin (CREON®) in patients with pancreatic exocrine insufficiency

OBJECTIVES

This study aimed to determine whether the efficacy of pancrelipase/pancreatin (CREON®) may be affected by the concomitant use of proton pump inhibitors (PPIs)/histamine-2 receptor antagonists (H2RAs).

METHODS

An analysis of integrated data from all clinical trials of pancrelipase/pancreatin supported by Abbott (34 trials, 1142 unique subjects) was conducted. All trials included patients with pancreatic exocrine insufficiency, and most cases were associated with cystic fibrosis, chronic pancreatitis, or pancreatic surgery. Study designs included single and double blind, open label, parallel group, and crossover, and most were randomized. The primary end point for this analysis was on-treatment coefficient of fat absorption (CFA) according to concomitant PPI/H2RA use (yes/no).

RESULTS

There were no meaningful differences in mean CFA values at the end of pancrelipase/pancreatin treatment by concomitant PPI/H2RA use: yes (n = 254), 82.7% versus no (n = 449), 84.2%. No meaningful differences were observed when the same analysis was carried out by disease type (cystic fibrosis, chronic pancreatitis, and pancreatic surgery).

CONCLUSIONS

This analysis of data from clinical trials enrolling patients with pancreatic exocrine insufficiency suggests that the efficacy of pancrelipase/pancreatin is not affected by concomitant PPI/H2RA use, as determined by end-of-treatment CFA values, and supports the treatment guidelines' recommendation that acid suppression is not routinely required with pancreatic enzyme replacement therapy.

Chronic pancreatitis: report from a multicenter Italian survey (PanCroInfAISP) on 893 patients

BACKGROUND

No data on chronic pancreatitis in Italy are available yet.

AIM

To evaluate demographic, clinical, diagnostic and therapeutic aspects in patients suffering from chronic pancreatitis.

PATIENTS AND METHODS

Eligible patients were prospectively enrolled from 2000 to 2005. Information concerning demographic data, lifestyle risk factors, family and clinical history, associated factors (alcohol, autoimmunity, cystic dystrophy of the duodenal wall, obstruction, genetic mutations) concomitant diseases, diagnostic findings, and pharmacological, endoscopic and surgical therapy were gathered.

RESULTS

893 patients (74% males, mean age 53.7+/-15.2 years) were evaluated. 519/859 patients (60%) were drinkers and 555/840 (66%) were smokers. A strong positive correlation between drinking and cigarette consumption (R=0.53; p<0.0001) was found. Heavy alcohol consumption (>80g of alcohol/day for more than 5 years) was considered the most important risk factor in 300 patients (34%), obstruction in 238 (27%), alcohol and obstruction in 82 (9%), autoimmunity in 34 (4%), cystic dystrophy of the duodenal wall/groove pancreatitis in 55 (6%), gene mutations in 36 (4%), and none (idiopathic) in 148 (17%). Bile stones were diagnosed in 287 patients (33%) and cholecystectomy was performed in 329 patients (38%). Pancreatic calcifications were diagnosed in 547/879 patients (62%). Pancreatic surgery was performed in 273 patients (31%). Endoscopic sphincterotomy was performed in 371 patients (42%). Exocrine and endocrine insufficiency were found, respectively, in 373/834 (45%) and 275/885 patients (31%).

CONCLUSIONS

An unexpected low frequency of alcohol abuse and new emerging associated risk factors for chronic pancreatitis were observed in Italy.

Efficacy of lower than standard doses of pancreatic enzyme supplementation therapy during acid inhibition in patients with pancreatic exocrine insufficiency

GOAL

To compare, during strong acid inhibition with omeprazole, the effect of 2 different doses of an enteric-coated pancreatic enzyme preparation on fecal fat excretion and abdominal symptoms in patients with exocrine insufficiency due to chronic pancreatitis (CP).

BACKGROUND

Treatment with pancreatic enzymes reduces fecal fat excretion in patients with CP but is rather unsuccessful due to irreversible lipase inactivation at pH below 4.

STUDY

Sixteen patients with CP (3 women, 13 men; age 53+/-3 y) participated in this randomized double blind 2-way cross over study. Fecal fat excretion and fat intake were measured and abdominal symptoms (visual analog scales) were scored during a 2 weeks control period, during omeprazole 60 mg+pancreatic enzymes 10,000 Fédération Internationale Pharmaceutique IU lipase tid (treatment A) for 2 weeks and during omeprazole 60 mg+pancreatic enzymes, 20,000 Fédération Internationale Pharmaceutique IU lipase tid (treatment B) for 2 weeks.

RESULTS

During acid inhibition with enzyme supplementation fecal fat excretion was significantly (P<0.01) reduced compared with control: 18+/-7 and 18+/-5 g/24 h versus 36+/-8 g/24 h for treatment A, B, and control, respectively. Abdominal symptom score and general well being improved significantly (P<0.05) during treatments A and B versus control. No differences in fat excretion or symptoms scores between treatments A and B were observed.

CONCLUSIONS

During strong acid inhibition, lower than recommended oral doses of pancreatic enzymes are therapeutically effective with respect to fat absorption and symptom reduction.

Quantitative study of digestive enzyme secretion and gastrointestinal lipolysis in chronic pancreatitis

BACKGROUND & AIMS

The contribution of human gastric lipase (HGL) to the overall lipolysis process in chronic pancreatitis (CP), as well as the relative pancreatic enzyme levels, rarely are addressed. This study was designed to quantify pancreatic and extrapancreatic enzyme output, activity, and stability in CP patients vs. healthy volunteers.

METHODS

Healthy volunteers (n = 6), mild CP patients (n = 5), and severe (n = 7) CP patients were intubated with gastric and duodenal tubes before the administration of a test meal. HGL, human pancreatic lipase (HPL), chymotrypsin, and amylase concentrations were assessed in gastric and duodenal samples by measuring the respective enzymatic activities. Intragastric and overall lipolysis levels at the angle of Treitz were estimated based on quantitative analysis of lipolysis products. Similar analyses were performed on duodenal contents incubated ex vivo for studying enzyme stability and evolution of lipolysis.

RESULTS

Although HPL, chymotrypsin, and amylase outputs all were extremely low, HGL outputs in patients with severe CP (46.8 +/- 31.0 mg) were 3-4-fold higher than in healthy controls (13.3 +/- 13.8 mg). Intragastric lipolysis did not increase, however, in patients with severe CP, probably because of the rapid decrease in the pH level of the gastric contents caused by a higher gastric acid secretion. HGL remains active and highly stable in the acidic duodenal contents of CP patients, and, overall, can achieve a significant lipolysis of the dietary triglycerides (30% of the control values) in the absence of HPL.

CONCLUSIONS

Although all pancreatic enzyme secretions are simultaneously reduced in severe CP, gastric lipase can compensate partly for the loss of pancreatic lipase but not normalize overall lipolytic activity.

No evidence of Helicobacter pylori sequences in pancreatic juices of patients affected by chronic pancreatitis

BACKGROUND

The course of chronic pancreatitis is often unpredictable and many factors are likely to be involved in the progression of the disease. In physiological condition, pancreatic juice exerts significant antibacterial activity, which is impaired in patients with chronic pancreatitis.

AIM

Hypothesizing that Helicobacter pylori could, in these conditions, lead to an ascending infection, we aimed to assess the presence of H. pylori sequences in pancreatic juices of patients with chronic pancreatitis.

METHODS

40 patients (mean age 52+/-3 yr) with alcoholic chronic pancreatitis and H. pylori infection were examined. Pancreatic juices were collected during endoscopic retrograde cholangiopancreatography. Using polymerase chain reaction (PCR) with two primers homologous to a portion of urease-C gene, H. pylori DNA was detected. Gastric biopsies, microscopically positive to H. pylori were used as positive controls.

RESULTS

All gastric biopsies produced H. pylori-specific DNA products. Conversely, no H. pylori urease-C gene sequences have been detected in any of the pancreatic juices.

CONCLUSION

Our data suggest that the impaired antibacterial activity of pancreatic juices in patients affected by chronic pancreatitis does not have a permissive role for a superimposing H. pylori infection in the pancreas. The possibility that Helicobacter species other than pylori may be involved in a superimposing infection requires further investigation.

Circadian coupling between pancreatic secretion and intestinal motility in humans

Human interdigestive intestinal motility follows a circadian rhythm with reduced nocturnal activity, but circadian pancreatic exocrine secretion is unknown. To determine whether circadian changes in interdigestive pancreatic secretion occur and are associated with motor events, pancreatic enzyme outputs, proximal jejunal motility, and plasma pancreatic polypeptide concentrations were measured during consecutive daytime and nighttime periods (12 h each) in seven healthy volunteers using orojejunal multilumen intubation. Studies were randomly started in the morning or evening. Nocturnally, motility decreased (motor quiescence: 67 +/- 22 vs. 146 +/- 37 min; motility index: 3.59 +/- 0.33 vs. 2.78 +/- 0.40 mmHg/min; both P < 0.05) but amylase output increased (273 +/- 78 vs. 384 +/- 100 U/min; P < 0.05) and protease output remained unchanged (P > 0.05); consequently, enzyme/motility ratio increased. Amylase outputs were always lowest during phase I. Motor but not pancreatic circadian activities were associated with sleep. Pancreatic polypeptide plasma concentrations were unchanged. Consequently, intestinal motor and pancreatic exocrine functions may have different circadian rhythms, i.e., decreased motor and stable secretory activity during the night. However, the association between individual phases of interdigestive motor and secretory activity is preserved. The nocturnal increase in enzyme/motility ratio is probably not caused by increased cholinergic tone.

Circadian gastric acidity and Helicobacter pylori infection in patients with chronic pancreatitis

A high prevalence of duodenal ulcer has been reported in patients with chronic pancreatitis. Data from previous studies on gastric acid secretion in these patients have provided conflicting results, and the potential role of H. pylori infection has been poorly investigated. The aim of this study was to assess the circadian pattern of gastric acidity and the prevalence of H. pylori infection in a group of patients suffering from this disease. Thirty-five patients with chronic pancreatitis ascertained by means of pancreatic calcifications or ductal alterations revealed by ERCP were recruited for this prospective study. They underwent 24-hr gastric pH-metry with glass minielectrodes positioned in the gastric corpus, and their profile of gastric acidity was compared with that of 35 healthy subjects, matched for age and sex. H. pylori infection was diagnosed by means of serology. There was no statistical difference (P = NS) in gastric pH of circadian, nocturnal, daytime, and postprandial periods between healthy subjects and patients with chronic pancreatitis. The prevalence of H. pylori infection was rather low (31%) in our patients and similar to that of a comparable control population (37%) in our geographical area. In conclusion, our study shows that patients with chronic pancreatitis have a circadian pattern of gastric acidity similar to that of normal subjects. Moreover, the prevalence of H. pylori infection is low in this population. These findings greatly differentiate the ulcer diathesis in chronic pancreatitis from that of patients with ordinary duodenal ulcer and suggest that other factors are implicated in the ulcerogenic process.

Post-prandial intragastric and duodenal acidity are increased in patients with chronic pancreatitis

OBJECTIVES

Patients with chronic pancreatitis and exocrine insufficiency have lower intraduodenal pH compared to controls. It has been assumed that abnormal low intraduodenal pH in these patients not only results from impaired pancreatic bicarbonate secretion but also from an increased gastric acid load to the duodenum.

METHODS

We have tested this hypothesis by combined intragastric and intraduodenal 24 h pH monitoring in nine chronic pancreatitis patients with exocrine pancreatic insufficiency and nine healthy control subjects during standardized test conditions. Postprandial gastrin and cholecystokinin release were also determined.

RESULTS

Median 24-h intraduodenal pH (5.90 vs. 6.00) and intragastric pH (1.60 vs. 1.70) were not significantly different between patients and controls. However, in the 2-h postprandial periods intraduodenal pH was below five for a significantly higher percentage of time in chronic pancreatitis patients compared to controls (lunch: 14.5% vs. 0.17%, P=0.011; dinner: 24.1% vs. 5.75%, P=0.05). The post-dinner intragastric pH was below three for a significantly higher percentage of time in chronic pancreatitis patients vs. controls (72.2 vs. 48.9%, P=0.04). Postprandial gastrin release was not significantly different between the two groups. Postprandial secretion of cholecystokinin (CCK), as enterogastrone, was significantly (P < 0.01) reduced in chronic pancreatitis patients (78 +/- 13 pmol/L, 120 min) compared to controls (155 +/- 14 pmol/L, 120 min).

CONCLUSIONS

Median intraduodenal and intragastric pH are not significantly decreased in patients with chronic pancreatitis and exocrine insufficiency but the postprandial time with an acidic pH in the duodenum (pH < 5) and in the stomach (pH < 3) is significantly (P </= 0.05) increased.

Long-term follow-up of patients with chronic pancreatitis in Italy

BACKGROUND

We investigated the epidemiologic, clinical, and radiologic aspects of a mixed medicosurgical series of chronic pancreatitis patients observed at the University of Verona Centre for the Study of Pancreatic Diseases over the period 1971-1995.

METHODS

Even though the pathogenesis of chronic pancreatitis has yet to be clarified and the classification is still debatable, the patients were subdivided in accordance with the Marseilles-Rome classification into those with alcoholic, obstructive, familial, and idiopathic forms of the disease. A total of 715 patients were analysed with a median follow-up period of 10 years (range, 1-25 years).

RESULTS AND CONCLUSIONS

At the end of follow-up the dropout rate amounted to 7.1% (51 patients), and 176 patients (24.6%) had died. Data are reported about the type of chronic pancreatitis, sex, and age distribution at the onset of the disease, drinking and smoking habits before onset and during follow-up, and incidence of calcifications, pain, diabetes, steatorrhoea, and pseudocysts. Surgical aspects, survival curves, and causes of death are also analysed, and the most frequent concomitant diseases in chronic pancreatitis sufferers are discussed.

Prevalence of Helicobacter pylori infection and gastric mucosal abnormalities in chronic pancreatitis

OBJECTIVE

Chronic pancreatitis is often associated with abnormal gastric acid secretion. However, previous studies have taken into consideration neither the potential role of Helicobacter pylori (H. pylori) infection nor histological features of the gastric mucosa in this context. The aim of this study was to analyze the prevalence of H. pylori infection as well as the pattern of gastritis in patients with chronic pancreatitis.

METHODS

Forty patients with chronic alcoholic pancreatitis were included in the study: 40 patients with alcoholic liver cirrhosis and normal exocrine pancreatic function and 40 asymptomatic nonalcoholic subjects matched for age and sex used as control subjects. Endoscopy was performed in all patients, and five biopsy specimens from the antrum (three from the gastric body and two from the cardia) were taken for histological grading of gastritis and H. pylori assessment.

RESULTS

Prevalence of H. pylori infection was similar in subjects with chronic pancreatitis (38%), asymptomatic subjects (28%) and liver cirrhosis (30%). Topography and expression of H. pylori-associated chronic gastritis was also not different among the three groups of subjects. In H. pylori-negative subjects, the presence of moderate to severe chronic antral gastritis was significantly more common in patients with chronic pancreatitis (40%) than in subjects with liver cirrhosis (18%) and in asymptomatic subjects (14%) (p < 0.05). No difference was found among the three groups of patients with regard to gastritis activity, atrophy, and intestinal metaplasia in the various gastric regions. The chronicity grade of gastritis did not correlate with the severity of pancreatic insufficiency.

CONCLUSION

Prevalence of H. pylori infection is not different in patients with chronic pancreatitis as compared with subjects alcoholic liver cirrhosis and asymptomatic subjects. A severe H. pylori-negative chronic gastritis is more common in patients with chronic pancreatitis. This chronic inflammation of the gastric mucosa could contribute to determining the changes in gastric physiology described in patients with chronic pancreatitis.

Effect of omeprazole 40 mg once daily on intraduodenal and intragastric pH in H. pylori-negative healthy subjects

There is a lack of information about the effect of omeprazole or other antisecretory drugs on intraduodenal pH. Aim of the study was to document the variation over time of intraduodenal pH during a 24-hr period and to simultaneously study the effect of omeprazole 40 mg once daily on intragastric and intraduodenal pH in healthy H. pylori-negative subjects. In a randomized, placebo-controlled study, eight subjects (five women, three men, mean age 22.7 years) received oral 40 mg omeprazole or placebo once daily for eight days. On day 7, intragastric and intraduodenal pH was measured continuously for 24 hr, using two miniature glass-membrane electrodes placed in the stomach (fundus) and in the distal third of the duodenum. The 24-hr median intraduodenal pH was 5.95 with placebo and 5.85 with omeprazole. Median intragastric pH was 1.68 without and 4.93 with omeprazole. During omeprazole therapy, intragastric pH fell below 4.0 in five of eight subjects. In the 2- and 3-hr postprandial periods, the percentage of time with pH < 5 was significantly reduced with omeprazole. In healthy subjects, 24-hr median and postprandial pH in the distal part of the duodenum was lower than previously thought. Omeprazole significantly reduced the percentage of time with pH < 5 postprandially. At night, intragastric pH fell below 4.0 with omeprazole 40 mg once daily. Omeprazole does not change 24-hr median intraduodenal pH significantly.