A nonpancreatic source of the proteolytic-enzyme amidase and bacteriology in experimental acute pancreatitis

Emerging Therapies to Prevent Post-ERCP Pancreatitis

PURPOSE OF REVIEW

The aim of this review is to evaluate emerging, novel therapies for the prevention of post-ERCP pancreatitis.

RECENT FINDINGS

Rectal indomethacin reduces the risk of pancreatitis in low- and average-risk patients, who comprise the majority of patients undergoing ERCP. An 8-h protocol of aggressive lactated Ringer's reduces the risk of pancreatitis in average-risk patients. Sublingual nitrate may provide additional benefit to rectal NSAIDs in preventing PEP. A tacrolimus trough > 2.5 ng/mL was recently shown to be associated with a lower risk of PEP in liver transplant patients undergoing ERCP. Routine usage of rectal indomethacin in all patients undergoing ERCP reduces the risk of PEP. Pancreatic-duct stents reduce the risk of PEP in high-risk patients. There is emerging data that aggressive hydration with lactated Ringer's and nitrates may further reduce PEP. Tacrolimus is a promising potential agent to prevent PEP but needs further clinical study.

Early bacterial infection of the pancreas and course of disease in cerulein-induced acute pancreatitis in rats

BACKGROUND

Bacterial infection of the pancreas aggravates the course of acute pancreatitis. Since bacterial translocation from the gut is likely to be an early event, in an animal model of pancreatitis, we investigated the effect of early bacterial supra-infection of the pancreas on the course of the disease.

METHODS

Six hours after the induction of acute pancreatitis in male Wistar rats (n = 180) by supramaximal stimulation with cerulein (or placebo in a control group), the animals were operated and a suspension of Helicobacter pylori, Escherichia coli or saline were introduced either in the pancreatic duct or interstitium (12 groups of 15 rats each); after 24 h, animals were killed and the following parameters analysed: macroscopic and histologic appearance of the pancreas (score), wet-to-dry weight ratio, pancreas trypsinogen activation peptide level, serum amylase, interleukin-6 and phospholipase A2 activity.

RESULTS

All parameters were increased in rats with cerulein-induced pancreatitis in comparison to placebo. Interstitial and intraductal application of bacteria increased the pancreatic damage. This effect was more evident with the application of E. coli in both cerulein and placebo groups. Application of E. coli but not of H. pylori determined pancreatic activation of trypsinogen, increased mortality and induced the production of interleukin-6.

CONCLUSIONS

Bacterial invasion of the pancreas worsens the histologic and clinical picture of disease and induces a systemic inflammatory response.

Increased nitric oxide excretion in patients with severe acute pancreatitis: evidence of an endotoxin mediated inflammatory response?

BACKGROUND AND AIMS

Nitric oxide represents a potential key mediator of the local and systemic manifestations of acute pancreatitis (AP) in experimental models but its role in human disease is uncertain. We therefore sought to assess if systemic nitric oxide (NO) production is elevated in severe AP and determine whether this is a reflection of biochemical severity or endotoxin exposure.

PATIENTS AND METHODS

Patients were recruited within 72 hours of pain onset. NO derived nitrite excretion determined from a 24 hour sterile urine collection was correlated with intestinal macromolecular permeability (polyethylene glycol excretion ratio), markers of systemic endotoxin exposure (IgG:IgM endotoxin core antibody (EndoCAb) ratio), disease severity, and the magnitude of systemic inflammation (peak C reactive protein (CRP) and Acute Physiology and Chronic Health Evaluation score II (APACHE-II)).

RESULTS

In patients with a severe attack (n=20), nitrite excretion was increased significantly compared with patients with a mild attack (n=45, 20.6 micro g v 15.65 micro g; p<0.00) and the latter with healthy controls (n=20, p=0.004). Nitrite excretion correlated strongly with both intestinal permeability (r=0.7, p=0.006) and EndoCAb ratio (r=0.7, p<0.01) but not with CRP or APACHE-II scores (p>0.1).

CONCLUSIONS

Total urinary nitrite excretion is increased in patients with severe AP, and may not be simply a reflection of systemic inflammation, but potentially a consequence of endotoxin mediated upregulation of inducible NO synthase activity.

Intestinal hypoperfusion contributes to gut barrier failure in severe acute pancreatitis

Intestinal barrier failure and subsequent bacterial translocation have been implicated in the development of organ dysfunction and septic complications associated with severe acute pancreatitis. Splanchnic hypoperfusion and ischemia/reperfusion injury have been postulated as a cause of increased intestinal permeability. The urinary concentration of intestinal fatty acid binding protein (IFABP) has been shown to be a sensitive marker of intestinal ischemia, with increased levels being associated with ischemia/reperfusion. The aim of the current study was to assess the relationship between excretion of IFABP in urine, gut mucosal barrier failure (intestinal hyperpermeability and systemic exposure to endotoxemia), and clinical severity. Patients with a clinical and biochemical diagnosis of acute pancreatitis were studied within 72 hours of onset of pain. Polyethylene glycol probes of 3350 kDa and 400 kDa were administered enterally, and the ratio of the percentage of retrieval of each probe after renal excretion was used as a measure of intestinal macromolecular permeability. Collected urine was also used to determine the IFABP concentration (IFABP-c) and total IFABP (IFABP-t) excreted over the 24-hour period, using an enzyme-linked immunosorbent assay technique. The systemic inflammatory response was estimated from peak 0 to 72-hour plasma C-reactive protein levels, and systemic exposure to endotoxins was measured using serum IgM endotoxin cytoplasmic antibody (EndoCAb) levels. The severity of the attack was assessed on the basis of the Atlanta criteria. Sixty-one patients with acute pancreatitis (severe in 19) and 12 healthy control subjects were studied. Compared to mild attacks, severe attacks were associated with significantly higher urinary IFABP-c (median 1092 pg/ml vs. 84 pg/ml; P < 0.001) and IFABP-t (median 1.14 microg vs. 0.21 microg; P = 0.003). Furthermore, the control group had significantly lower IFABP-c (median 37 pg/ml; P = 0.029) and IFABP-t (median 0.06 microg; P = 0.005) than patients with mild attacks. IFABP correlated positively with the polyethylene glycol 3350 percentage retrieval (r = 0.50; P < 0.001), CRP (r = 0.51; P < 0.001), and inversely with serum IgM EndoCAb levels (r = -0.32; P = 0.02). The results of this study support the hypothesis that splanchnic hypoperfusion contributes to the loss of intestinal mucosal integrity associated with a severe attack of pancreatitis.

Therapeutic efficacy of continuous arterial infusion of an antibiotic and a protease inhibitor via the superior mesenteric artery for acute pancreatitis in an animal model

The major cause of death in acute pancreatitis is severe infection owing to bacterial translocation. As a new strategy, we investigated the effects of continuous intra-arterial infusion of an antibiotic (imipenem) or protease inhibitor (nafamostat mesylate) via the superior mesenteric artery (SMA) on bacterial translocation in acute pancreatitis. Infusion of saline (group I), nafamostat mesylate (group II), or imipenem (group III) was started 6 hours after inducing acute pancreatitis in dogs by infusing autologous gallbladder bile into the main pancreatic duct. The survival rate in group III was significantly improved compared to group I(100 vs. 30% at 24 hours), and bacterial infection of the peritoneal fluid, mesenteric lymph nodes, and pancreas was completely prevented in group III. Intestinal damage assessed by light and scanning electron microscopy and by biochemical parameters (mucosal protein content and myeloperoxidase activity) was also significantly mitigated in group III, which showed milder pancreatic necrosis as well. There was little beneficial effect in preventing bacterial translocation in group II, although the survival rate at 24 hours (70%) was improved. Continuous arterial infusion of an antibiotic via the SMA is effective in mitigating intestinal mucosal damage and preventing bacterial translocation in acute pancreatitis, thereby improving survival.

Does bile of patients with acute gallstone pancreatitis cause pancreatic inflammatory lesions? A study of the pancreatic toxicity of choledochal secretions collected at ERCP

BACKGROUND

Bile flow into the pancreatic duct has been proposed as the cause of acute biliary pancreatitis. However, the pancreatic toxicity of choledochal bile from patients with acute gallstone pancreatitis has not been studied.

METHODS

Bile was collected endoscopically from the common bile ducts of 21 patients with acute gallstone pancreatitis within 72 hours after the onset of disease. The bile samples were instilled into the pancreatic duct of rabbits, and light microscopic examination of the pancreas morphology was performed to assess the toxicity of human bile. Microbiologic quantitative analysis of the aerobic and anaerobic bacterial bile flora was performed.

RESULTS

Bile of six patients with acute gallstone pancreatitis (29%) induced interstitial inflammation in the rabbit pancreas. Choledochal bile of these patients harbored more than 10(4) CFU/mL bacteria (Proteus vulgaris, n = 1; Klebsiella pneumoniae, n = 1; Escherichia coli, n = 2; enterococci, n = 2). After sterilization, the bile samples did not induce acute pancreatitis. In 15 patients (71%), bile did not cause acute pancreatitis in the rabbit pancreas. These choledochal secretions were sterile or contained less than 10(4) CFU/mL.

CONCLUSIONS

Reflux of infected bile may be a potential cause of acute pancreatitis in the minority of patients with bacterobilia. In most patients with gallstone pancreatitis, bile is neither infected nor harmful to the pancreas, and its flow into the gland is unlikely to be the cause of inflammation.

Early increase in intestinal permeability in patients with severe acute pancreatitis: correlation with endotoxemia, organ failure, and mortality

Sepsis accounts for 80% of deaths from acute pancreatitis. This study aimed to investigate early changes in intestinal permeability in patients with acute pancreatitis, and to correlate these changes with subsequent disease severity and endotoxemia. The renal excretion of enterally administered polyethylene glycol (PEG) 3350 and PEG 400 was measured within 72 hours of onset of acute pancreatitis to determine intestinal permeability. Severity was assessed on the basis of APACHE II scores and C-reactive protein measurements. Serum endotoxin and antiendotoxin antibodies were measured on admission. Eight-five patients with acute pancreatitis (mild in 56, severe in 29) and 25 healthy control subjects were studied. Urinary excretion of PEG 3350 (median) was significantly greater in patients who had severe attacks (0.61%) compared to those with mild disease (0.09%) and health control subjects (0.12%) (P <0. 0001), as was the permeability index (PEG 3350/400 excretion) (P <0. 00001). The permeability index was significantly greater in patients who subsequently developed multiple organ system failure and/or died compared with other severe cases (0.16 vs. 0.04) (P = 0.0005). The excretion of PEG 3350 correlated strongly with endotoxemia (r = 0.8; P = 0.002). Early increased intestinal permeability may play an important role in the pathophysiology of severe acute pancreatitis. Therapies that aim to restore intestinal barrier function may improve outcome.

Infected bile-induced acute pancreatitis in rabbits. The role of bacteria

CONCLUSIONS

Bacteria species commonly found in bile of patients with choledocholithiasis render human bile toxic to the pancreas. The severity of infected bile-induced acute pancreatitis depends on the bacterial species. Infected bile-induced acute pancreatitis turns into a sterile inflammation within 10 d.

BACKGROUND

Flow of bile into the pancreatic duct was proposed to cause some forms of gallstone pancreatitis. The development of bile-induced acute pancreatitis at physiologic ductal pressure is known to depend on the bacterial infection of bile. In this study, we investigated the effect of a variety of bacteria species commonly found in bile of patients with choledocholithiasis upon the pancreatic toxicity of human bile. The time-course of pancreatic infection in infected bile-induced acute pancreatitis was also analyzed.

METHODS

In rabbits, the pancreatic duct was kept obstructed throughout the experiment. After 24 h, 50 microL of pancreatic juice was obtained from the congested pancreatic duct and replaced with the same quantity of infected human bile. Bile contained bacteria (10(7) microorganisms/microL) of species frequently found in choledochal secretions of patients with gallstone disease. Effects on pancreatic morphology were studied after 48 h. In another experiment, the number of Escherichia coli/mg of pancreatic tissue was determined in a time sequence study following exposure of the rabbit pancreatic duct to 50 microL E. coli-infected bile (10(7) microorganisms/mL) and temporary (12 h) or permanent duct obstruction.

RESULTS

Sterile bile was not harmful to the pancreas. Infected bile caused an interstitial-edematous pancreatitis with occasional acinar necrosis. The severity of acute pancreatitis depended on the bacterial species. Following pancreatic duct exposure to E. coli-infected bile, there was complete clearance of the bacteria from the gland with a concomitant interstitial leukocyte infiltration within a period of 2-10 d.

Mechanisms of sepsis in acute pancreatitis in opossums

PURPOSE

To study the incidence and pathways of colonization of the pancreas by specific bacteria in a model of necrotizing pancreatitis.

METHODS

Bacteremia and splanchnic organ colonization were studied in the early course of necrotizing pancreatitis following common biliopancreatic duct ligation (BPDL) of the opossum. Nonoperated animals served as controls. Intestinal lymph nodes, liver, spleen, and pancreas were cultured following bacteremia or sacrifice.

RESULTS

In opossums with sterile bile, bacteria were recovered from 28.6% of blood cultures after BPDL (n = 10) and from 12.0% in controls (n = 10, P < 0.05). Animals that underwent BPDL revealed enteric microorganisms in intestinal lymph nodes (6), liver (3), spleen (4), and pancreas (4). Ten animals carried Salmonella within their bile (5 controls, 5 BPDL animals). Following BPDL, they developed rapid bacteremia and colonization of organs, pancreatic ductal rupture, and extravasation of bacteria and bile into the interstitium.

CONCLUSION

There are two possible mechanisms for the development of bacterial colonization in opossum pancreatitis: bacterial translocation of enteric organisms from gut lumen to mesenteric lymph nodes and subsequent hematogenous dissemination and transductal infestation from the biliary tract.

[Effect of cecostomy on the pathophysiology and prognosis of acute experimental pancreatitis]

In 76 male wistar rats with a median weight of 340 g acute pancreatitis was induced by injection of 2% sodium taurocholate into a temporarily closed duodenal loop. 40 animals received an additional cecostomy (group B), the others served as controls (group A). The postoperative figures for amylase, leucocyte count, and hemoglobin were nearly identical in both groups. According to histologic criteria acute pancreatitis was comparable in both groups, too. In nine rats endotoxin was found elevated postoperatively (13.4%). Seven animals belonged to the control (22.6%) and only two to the cecostomy group (5.6%). The difference was statistically significant (p less than 0.05). Also the differences between the median serum endotoxin levels reached statistic significance (79 ng/l in group B vs. 219 ng/l in group A). Mortality was significantly increased in endotoxin-positive animals (42.9% vs. 19.4%). Additionally, among the animals of the control group alterations of the colonic mucosa were observed more frequently than in the cecostomy group. The results are in favour of a translocation of endotoxin from the gut lumen into the circulation during acute experimental pancreatitis.

Pancreatic juice in the peritoneal cavity: antibiotics or omental preservation prevent mortality

Pancreatic juice without bile will accumulate if the pancreatic duct communicates with the peritoneal cavity. We tested the effect of antibiotics or omentectomy on mortality in dogs where the pancreatic duct drained into the peritoneal cavity. Under sterile conditions the head of the pancreas was excised, the duodenum was preserved, and the body and tail of the pancreas remained in situ. The pancreatic duct was either ligated or left open to drain into the peritoneal cavity. Thirty-two dogs were prepared and divided into four groups by the status of the pancreatic duct, the use of omentectomy, or the administration of two doses of penicillin G procaine (20,000 units/kg) given before and then 24 hr after operation. The dogs were observed for mortality over a 1-month period. If a mortality occurred, the etiology was determined at autopsy. After excision of the omentum, the mortality rate was significantly higher if the pancreatic duct was allowed to drain into the peritoneal cavity than if the duct was ligated. Mortality decreased within the duct open group if only antibiotics were given (significant) or if only the omentum was preserved (not significant). This study indicates the importance of bacterial contamination or omental function when pancreatic juice is present in the peritoneal cavity.

Bacterial contamination of pancreatic necrosis. A prospective clinical study

In a prospective clinical study including 114 patients with acute necrotizing pancreatitis, but excluding patients with a pancreatic abscess, necrotic material obtained at surgery was tested bacteriologically. Intestinal microorganisms were cultured in 39.4% of the cases. The contamination rate was 23.8% in patients operated on during the first 7 days of the attack; it rose to 71.4% in the third week and decreased to 32.5% after the fourth week. Intra- and extrapancreatic necrosis was more widespread and pancreatitis-associated ascites was more frequent in patients with proven contamination. The number of objective signs was 4.5 (median) and postoperative mortality was 37.8% in bacteriologically positive subjects, whereas the number was 3.5 (median) and mortality was 8.7% in bacteriologically negative patients. Morphologic and clinical alterations were more severe, and the mortality rate was significantly elevated, in patients with a short history of disease and bacterial contamination of necrotic tissue. All 5 patients with pancreatic sepsis who were operated on in the first 7 days of the disease, as compared with 2 of 16 patients with sterile necrosis, died. Thus, it is demonstrated that bacterial contamination of pancreatic necrosis occurs early and frequently, causing a significant increase in morbidity and mortality, particularly when it develops in the initial stages of the attack.

Timing of surgery for acute biliary pancreatitis

Twenty-five patients with acute biliary pancreatitis were classified according to the severity of disease as determined by Ranson's signs. A significant correlation was found between the severity of pancreatitis estimated in this way and the observed postoperative mortality. Early operation was performed in 15 patients, whereas 10 patients received conservative management for a certain period before operation. The choice of treatment was based on clinical considerations. No significant difference was found in mortality between the two groups. We conclude that early operation does not harm patients with mild pancreatitis whereas patients with severe pancreatitis may benefit from it.

Results of mobilization and drainage of the pancreas for acute pancreatitis

The surgical treatment of acute pancreatitis remains controversial. Since 1969, we treated 60 patients with acute pancreatitis. In 34 with severe acute pancreatitis who were not responding adequately to intensive medical care, surgical intervention was made by mobilization of the pancreas from retroperitoneal tissue and drainage of the pancreatic bed (M-D procedure). Thirty-four operative cases were classified into 7 edematous, 7 hemorrhagic, and 20 necrotizing. Macroscopic findings of the pancreas did not correlate either to the severity of the acute pancreatitis or to the mortality rate. Eight of 34 who underwent M-D procedure died (23 per cent), but the rate became 14.7 per cent after excluding 3 who died of unrelated causes. These data suggest that the M-D procedure is highly effective in the treatment of early cases of severe acute pancreatitis. There was an associated marked reduction in the mortality rate with the prophylactic use of broad spectrum antibiotics. With M-D procedure, there was a low incidence of late sequelae of pancreatic or peripancreatic abscess.

Early histological changes in acute necrotizing hemorrhagic pancreatitis. A retrospective pathological study of 20 total pancreatectomy specimens

Settled lesions of acute necrotizing hemorrhagic pancreatitis have been commonly reported. Early alterations remained unknown. In a retrospective pathological study of 20 total pancreatectomy specimens, early changes have been evidenced in "grossly unmodified" areas of pancreas: acinar cells homogenization, ductal dilatation with epithelial degeneration, diffuse interstitial edema and fibroblastic reaction, necrotic angeitis . These alterations were identical to the changes described in experimental studies.

Effects of ethanol on the sphincter of Oddi: an endoscopic manometric study

The effects of ethanol, given either intragastrically or intravenously, on the sphincter of Oddi was evaluated by endoscopic manometry. In 12 subjects intragastric ethanol (150 ml of 32%) was given over 10 minutes. In five control subjects saline solution (150 ml of 0.9%) was given intragastrically instead of ethanol. In five other subjects ethanol was infused intravenously (6 ml/kg of 10%) for 36 minutes. Ethanol given intragastrically produced a significant inhibitory effect on sphincter of Oddi pressure. Peak pressure fell from a control value of 75.7 +/- 26.35 mmHg to 39 +/- 15.39 mmHg (p less than 0.001) at 35 minutes. Basal pressure fell from a control value of 30.17 +/- 19.47 mmHg to 11.83 +/- 6.35 mmHg (p less than 0.01) at 35 minutes. Wave height fell from a control value of 41.33 +/- 15.4 mmHg to 27.16 +/- 11.25 mmHg (p less than 0.02) at 35 minutes. No effects on sphincter of Oddi wave frequency were observed. No significant modifications of sphincter motor activity were observed after intragastric saline infusion. Ethanol given intravenously also produced an appreciable inhibitory effect on sphincter of Oddi pressure, without affecting its wave frequency.

Pancreatic blood flow in experimental acute pancreatitis

The etiology and pathogenesis of acute necrotizing hemorrhagic pancreatitis remain controversial. Recent work has suggested that an early fall in pancreatic blood flow, causing ischemia, may be the initiating factor. Using an established rat model of hemorrhagic pancreatitis and the fractional indicator distribution technique with 86RbCl, pancreatic blood flow and tissue perfusion have been measured at various times in the condition. Six groups of ten rats were studied: control sham operation and pancreatitis groups were sacrificed at 1, 6, and 24 hr. Pancreatic blood flow (% of cardiac output) and perfusion (blood flow/g tissue) were measured. Blood flow was increased by a maximum of 53% at 1 hr (P less than 0.001) and remained elevated for 24 hr, and perfusion was increased by a maximum of 70% (P less than 0.001) at 1 hr and remained elevated at 6 hr. Pancreatic perfusion declines after 6 hr due to increasing gland edema. The results demonstrate a significant increase in pancreatic blood flow and perfusion in experimentally induced acute pancreatitis, suggesting a primary inflammatory response, and refute the ischemic etiological theory.

Early increase in intestinal permeability in patients with severe acute pancreatitis: correlation with endotoxemia, organ failure, and mortality

Sepsis accounts for 80% of deaths from acute pancreatitis. This study aimed to investigate early changes in intestinal permeability in patients with acute pancreatitis, and to correlate these changes with subsequent disease severity and endotoxemia. The renal excretion of enterally administered polyethylene glycol (PEG) 3350 and PEG 400 was measured within 72 hours of onset of acute pancreatitis to determine intestinal permeability. Severity was assessed on the basis of APACHE II scores and C-reactive protein measurements. Serum endotoxin and antiendotoxin antibodies were measured on admission. Eight-five patients with acute pancreatitis (mild in 56, severe in 29) and 25 healthy control subjects were studied. Urinary excretion of PEG 3350 (median) was significantly greater in patients who had severe attacks (0.61%) compared to those with mild disease (0.09%) and health control subjects (0.12%) (P <0. 0001), as was the permeability index (PEG 3350/400 excretion) (P <0. 00001). The permeability index was significantly greater in patients who subsequently developed multiple organ system failure and/or died compared with other severe cases (0.16 vs. 0.04) (P = 0.0005). The excretion of PEG 3350 correlated strongly with endotoxemia (r = 0.8; P = 0.002). Early increased intestinal permeability may play an important role in the pathophysiology of severe acute pancreatitis. Therapies that aim to restore intestinal barrier function may improve outcome.

Early increase in intestinal permeability in patients with severe acute pancreatitis: correlation with endotoxemia, organ failure, and mortality

Sepsis accounts for 80% of deaths from acute pancreatitis. This study aimed to investigate early changes in intestinal permeability in patients with acute pancreatitis, and to correlate these changes with subsequent disease severity and endotoxemia. The renal excretion of enterally administered polyethylene glycol (PEG) 3350 and PEG 400 was measured within 72 hours of onset of acute pancreatitis to determine intestinal permeability. Severity was assessed on the basis of APACHE II scores and C-reactive protein measurements. Serum endotoxin and antiendotoxin antibodies were measured on admission. Eight-five patients with acute pancreatitis (mild in 56, severe in 29) and 25 healthy control subjects were studied. Urinary excretion of PEG 3350 (median) was significantly greater in patients who had severe attacks (0.61%) compared to those with mild disease (0.09%) and health control subjects (0.12%) (P <0. 0001), as was the permeability index (PEG 3350/400 excretion) (P <0. 00001). The permeability index was significantly greater in patients who subsequently developed multiple organ system failure and/or died compared with other severe cases (0.16 vs. 0.04) (P = 0.0005). The excretion of PEG 3350 correlated strongly with endotoxemia (r = 0.8; P = 0.002). Early increased intestinal permeability may play an important role in the pathophysiology of severe acute pancreatitis. Therapies that aim to restore intestinal barrier function may improve outcome.