Endocannabinoids and endocannabinoid-like compounds modulate hypoxia-induced permeability in CaCo-2 cells via CB1, TRPV1, and PPARα

BACKGROUND AND PURPOSE

We have previously reported that endocannabinoids modulate permeability in Caco-2 cells under inflammatory conditions and hypothesised in the present study that endocannabinoids could also modulate permeability in ischemia/reperfusion.

EXPERIMENTAL APPROACH

Caco-2 cells were grown on cell culture inserts to confluence. Trans-epithelial electrical resistance (TEER) was used to measure permeability. To generate hypoxia (0% O2), a GasPak™ EZ anaerobe pouch system was used. Endocannabinoids were applied to the apical or basolateral membrane in the presence or absence of receptor antagonists.

KEY RESULTS

Complete hypoxia decreased TEER (increased permeability) by ~35% after 4 h (recoverable) and ~50% after 6 h (non-recoverable). When applied either pre- or post-hypoxia, apical application of N-arachidonoyl-dopamine (NADA, via TRPV1), oleamide (OA, via TRPV1) and oleoylethanolamine (OEA, via TRPV1) inhibited the increase in permeability. Apical administration of anandamide (AEA) and 2-arachidonoylglycerol (2-AG) worsened the permeability effect of hypoxia (both via CB1). Basolateral application of NADA (via TRPV1), OA (via CB1 and TRPV1), noladin ether (NE, via PPARα), and palmitoylethanolamine (PEA, via PPARα) restored permeability after 4 h hypoxia, whereas OEA increased permeability (via PPARα). After 6 h hypoxia, where permeability does not recover, only basolateral application PEA sustainably decreased permeability, and NE decreased permeability.

CONCLUSIONS AND IMPLICATIONS

A variety of endocannabinoids and endocannabinoid-like compounds modulate Caco-2 permeability in hypoxia/reoxygenation, which involves multiple targets, depending on whether the compounds are applied to the basolateral or apical membrane. CB1 antagonism and TRPV1 or PPARα agonism may represent novel therapeutic targets against several intestinal disorders associated with increased permeability.

Cannabinoids mediate opposing effects on inflammation-induced intestinal permeability

BACKGROUND AND PURPOSE

Activation of cannabinoid receptors decreases emesis, inflammation, gastric acid secretion and intestinal motility. The ability to modulate intestinal permeability in inflammation may be important in therapy aimed at maintaining epithelial barrier integrity. The aim of the present study was to determine whether cannabinoids modulate the increased permeability associated with inflammation in vitro.

EXPERIMENTAL APPROACH

Confluent Caco-2 cell monolayers were treated for 24 h with IFNγ and TNFα (10 ng·mL(-1) ). Monolayer permeability was measured using transepithelial electrical resistance and flux measurements. Cannabinoids were applied either apically or basolaterally after inflammation was established. Potential mechanisms of action were investigated using antagonists for CB(1) , CB(2) , TRPV1, PPARγ and PPARα. A role for the endocannabinoid system was established using inhibitors of the synthesis and degradation of endocannabinoids.

KEY RESULTS

Δ(9) -Tetrahydrocannabinol (THC) and cannabidiol accelerated the recovery from cytokine-induced increased permeability; an effect sensitive to CB(1) receptor antagonism. Anandamide and 2-arachidonylglycerol further increased permeability in the presence of cytokines; this effect was also sensitive to CB(1) antagonism. No role for the CB(2) receptor was identified in these studies. Co-application of THC, cannabidiol or a CB(1) antagonist with the cytokines ameliorated their effect on permeability. Inhibiting the breakdown of endocannabinoids worsened, whereas inhibiting the synthesis of endocannabinoids attenuated, the increased permeability associated with inflammation.

CONCLUSIONS AND IMPLICATIONS

These findings suggest that locally produced endocannabinoids, acting via CB(1) receptors play a role in mediating changes in permeability with inflammation, and that phytocannabinoids have therapeutic potential for reversing the disordered intestinal permeability associated with inflammation.

LINKED ARTICLES

This article is part of a themed section on Cannabinoids in Biology and Medicine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-8. To view Part I of Cannabinoids in Biology and Medicine visit http://dx.doi.org/10.1111/bph.2011.163.issue-7.

Pharmacological effects of cannabinoids on the Caco-2 cell culture model of intestinal permeability

Activation of cannabinoid receptors decreases emesis, inflammation, gastric acid secretion, and intestinal motility. However, the effects of cannabinoids on intestinal permeability have not yet been established. The aim of the present study is to examine the effects of cannabinoids on intestinal permeability in an in vitro model. Caco-2 cells were grown until fully confluent on inserts in 12-well plates. Transepithelial electrical resistance (TEER) measurements were made as a measure of permeability. EDTA (50 μM) was applied to reversibly increase permeability (reduce TEER). The effects of cannabinoids on permeability in combination with EDTA, or alone, were assessed. Potential target sites of action were investigated using antagonists of the cannabinoid (CB)(1) receptor, CB(2) receptor, transient receptor potential vanilloid subtype 1 (TRPV1), peroxisome proliferator-activated receptor (PPAR)γ, PPARα, and a proposed cannabinoid receptor. When applied to the apical or basolateral membrane of Caco-2 cells, Δ(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD) enhanced the speed of recovery of EDTA-induced increased permeability. This effect was sensitive to cannabinoid CB(1) receptor antagonism only. Apical application of endocannabinoids caused increased permeability, sensitive to cannabinoid CB(1) receptor antagonism. By contrast, when endocannabinoids were applied basolaterally, they enhanced the recovery of EDTA-induced increased permeability, and this involved additional activation of TRPV1. All cannabinoids tested increased the mRNA of the tight junction protein zona occludens-1, but only endocannabinoids also decreased the mRNA of claudin-1. These findings suggest that endocannabinoids may play a role in modulating intestinal permeability and that plant-derived cannabinoids, such as THC and CBD, may have therapeutic potential in conditions associated with abnormally permeable intestinal epithelium.

Antibiotic therapy for prophylaxis against infection of pancreatic necrosis in acute pancreatitis

BACKGROUND

Acute pancreatitis is a common abdominal emergency with no specific treatment. Pancreatic necrosis may complicate severe attacks, detectable by computed tomography (CT). Necrosis can become infected, making surgical intervention necessary and increasing mortality to more than 40%. Experimental studies suggest that antibiotic therapy may prevent infection, but could promote resistance and fungal infection.

OBJECTIVES

To determine the effectiveness and safety of prophylactic antibiotics in acute pancreatitis complicated by pancreatic necrosis.

SEARCH STRATEGY

The Cochrane Library (Issue 1, 2006), MEDLINE (January 1966-December 2005), EMBASE (January 1980-December 2005) and CINAHL (January 1982-December 2005) were searched. We also examined Conference proceedings.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing antibiotics versus placebo in acute pancreatitis with CT proven necrosis were sought using a detailed search strategy without linguistic limitation. RCTs. Initial searching was undertaken in November 2001. Latest update: December 2005.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data independently for rates of primary end-points: mortality and pancreatic infection rates. Secondary end-points included: non pancreatic infection and operative rates. Adverse events: antibiotic resistance and fungal infections. Subgroup analyses: antibiotic regimen.

MAIN RESULTS

Five evaluable studies randomised 294 patients. Analysis suggested significantly less mortality with therapy (6%) versus controls (15.3%), odds ratio 0.37 (95% CI 0.17, 0.83). Infected pancreatic necrosis rates were not significantly different (therapy 20%, controls 27.8%), odds ratio 0.62 (95% CI 0.35, 1.09), and neither were operative treatment rates or non-pancreatic infection rates. Fungal infections were not significantly different at 4% with therapy versus 4.9% in controls, odds ratio 0.83 (95% CI 0.30, 2.27). There were no evaluable data on antibiotic resistance. Sub-group analysis was performed for antibiotic regimen: beta lactam (192 patients), and quinolone plus imidazole (102 patients). With beta lactam prophylaxis there was significantly less mortality (6.3%) versus controls (16.7%), odds ratio 0.34 (95% CI 0.13, 0.91), and infected pancreatic necrosis (15.6%) versus (29.2%) in controls, odds ratio 0.41 (95% CI 0.20, 0.85), but there were no significant differences in operative treatment rates or non-pancreatic infections. No significant differences were seen with quinolone plus imidazole.

AUTHORS' CONCLUSIONS

Antibiotic prophylaxis appeared to be associated with significantly decreased mortality but not infected pancreatic necrosis. Beta lactams were associated with significantly decreased mortality and infected pancreatic necrosis, but quinolone plus imidazole regimens were not. There were variations in methodological quality, treatment regimens, and a lack of data on adverse effects. Further better designed studies are needed to support antibiotic prophylaxis and, should these prove beneficial, to compare beta-lactams with quinolones directly.

Calcitonin precursors: early markers of gut barrier dysfunction in patients with acute pancreatitis

BACKGROUND

Severe acute pancreatitis is associated with an early increase in intestinal permeability and endotoxemia. Endotoxin is a potent stimulator for the production and release of procalcitonin and its components (calcitonin precursors; [CTpr]). The aim of this study is to evaluate the role of plasma CTpr as an early marker for gut barrier dysfunction in patients with acute pancreatitis.

METHODS

Intestinal permeability to macromolecules (polyethylene glycol 3350), serum endotoxin and antiendotoxin core antibodies, plasma CTpr, and serum C-reactive protein (CRP) were measured on admission in 60 patients with acute pancreatitis. Attacks were classified as mild (n = 48) or severe (n = 12) according to the Atlanta criteria.

RESULTS

Compared with mild attacks of acute pancreatitis, severe attacks were significantly associated with an increase in intestinal permeability index (median: 0.02 vs. 0.006, P < 0.001), the frequency of endotoxemia (73% vs. 41%, P = 0.04), and the extent of depletion of serum IgM antiendotoxin antibodies (median: 43 MMU vs. 100 MMU, P = 0.004). Plasma CTpr levels were significantly elevated in patients with severe attacks compared with mild attacks on both the day of admission and on day 3 (median: 64 vs. 22 fmol/mL, P = 0.03; and 90 vs. 29 fmol/mL, P = 0.003 respectively). A positive and significant correlation was observed between the admission serum endotoxin and plasma CTpr levels on admission (r = 0.7, P < 0.0001) and on day 3 (r = 0.96, P < 0.0001), and between plasma CTpr on day 7 and the intestinal permeability index (r = 0.85, P = 0.0001). In contrast, only a weak positive correlation was observed between peak serum levels of CRP and plasma CTpr on admission (r = 0.3, P = 0.017) and on day 7 (r = 0.471, P = 0.049), as well as between CRP and each of the admission serum endotoxin (r = 0.3, P = 0.03) and the intestinal permeability index (r = 0.375, P = 0.007).

CONCLUSIONS

In patients with acute pancreatitis, plasma concentrations of CTpr appear to reflect more closely the derangement in gut barrier function rather than the extent of systemic inflammation.

Laparoscopic cholecystectomy: are patients with biliary pancreatitis at increased operative risk?

BACKGROUND

Previous reports of laparoscopic cholecystectomy (LC) in patients with biliary pancreatitis suggested increased operative difficulty, high rates of conversion, and greater morbidity and mortality.

METHODS

Between 1990 and 1997, LC was performed for biliary pancreatitis in 63 patients (Group I) and for other causes in 829 patients (Group II).

RESULTS

Patients with biliary pancreatitis were significantly older (median age 57 vs 50 years, p = 0.009), with greater co-morbidity (ASA III/IV 24% vs 11%, p = 0.008). The groups were comparable with respect to the frequency of previous abdominal operations, acute inflammation of the gallbladder, and the frequency of bile duct calculi detected by intraoperative cholangiography. Moderate to severe adhesions involving the gallbladder were significantly more frequent in patients with biliary pancreatitis (46% vs 29%, p = 0.004). No significant differences were observed between the two groups with respect to intraoperative (1.5% Group I vs 6.0% Group II, p = 0.109) or postoperative complications (10% vs 8%, p = 0.426), conversion rate (0 vs 2.7%, p = 0.181), or duration of operation (median 92 vs 85 min, p = 0.33).

CONCLUSION

Despite increased age and co-morbidity and more frequent adhesions, our data showed no evidence that intraoperative or postoperative complications were more frequent in patients with biliary pancreatitis than in other patients undergoing LC.

Micropuncture cholecystectomy vs conventional laparoscopic cholecystectomy: a randomized controlled trial

BACKGROUND

The aim of this study was to compare micropuncture laparoscopic cholecystectomy (MPLC), with three 3.3-mm cannulas and one 10-mm cannula with conventional laparoscopic cholecystectomy (CLC).

METHODS

Patients were randomized to undergo either CLC or MPLC. The duration of each operative stage and the procedure were recorded. Interleukin-6 (IL-6), adrenocorticotropic hormone (ACTH), and vasopressin were sampled for 24 h. Visual analogue pain scores (VAPS) and analgesic consumption were recorded for 1 week. Pulmonary function and quality of life (EQ-5D) were monitored for 4 weeks. Statistical analysis was performed using the Mann-Whitney test or Fisher's exact test. Results are expressed as median (interquartile range).

RESULTS

Forty-four patients entered the study, but four were excluded due to unsuspected choledocholithiasis (n = 3) or the need to reschedule surgery (n = 1). The groups were comparable in terms of age, duration of symptoms, and indications for surgery. Total operative time was similar (CLC, 63 [52-81] min vs MPLC 74 [58-95] min; p = 0.126). However, time to place the cannulas after skin incision (CLC, 5:42 [3:45-6:37] min vs MPLC, 7:38 [5:57-10:15] min; p = 0.015) and to clip the cystic duct after cholangiography (CLC, 1:05 [0:40-1:35] min vs MPLC, 3:45 [2:26-7:49] min; p <0.001) were significantly longer for MPLC. Six CLC patients and one MPLC patient required postoperative parenteral opiates (p = 0.04). Oral analgesic consumption was similar in both groups (p = 0.217). Median VAPS were lower at all time points for MPLC, but this finding was not significant (p = 0.431). There were no significant differences in postoperative stay, IL-6, ACTH or vasopressin responses, pulmonary function, or EQ-5D scores.

CONCLUSIONS

The thinner instruments did not significantly increase the total duration of the procedure. MPLC reduced the use of parenteral analgesia postoperatively, which may prove beneficial for day case patients, but it did not have a significant impact on laboratory variables, lung function or quality of life.

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.

Calcitonin precursors in the prediction of severity of acute pancreatitis on the day of admission

BACKGROUND

Calcitonin precursors are sensitive markers of inflammation and infection. The aim of this study was to evaluate the role of plasma calcitonin precursor levels on the day of admission in the prediction of severity of acute pancreatitis, and to compare this with the Acute Physiology And Chronic Health Evaluation (APACHE) II scoring system.

METHODS

Plasma concentrations of calcitonin precursors were determined on admission in 69 patients with acute pancreatitis. APACHE II scores were calculated on admission. Attacks were classified as mild (n = 55) or severe (n = 14) according to the Atlanta criteria. Plasma calcitonin precursor levels were determined with a sensitive radioimmunoassay.

RESULTS

On the day of hospital admission, plasma levels of calcitonin precursors were significantly greater in patients with a severe attack compared with levels in those with a mild attack of pancreatitis (median 64 versus 25 fmol/ml; P = 0.014), but the APACHE II scores were no different (median 9 versus 8; P = 0.2). The sensitivity, specificity, positive predictive and negative predictive values, and accuracy for the prediction of severe acute pancreatitis were 67, 89, 57, 93 and 85 per cent respectively for plasma calcitonin precursor levels higher than 48 fmol/ml, and 69, 45, 23, 86 and 50 per cent respectively for an APACHE II score greater than 7. Differences in the specificity and accuracy of the two prognostic indicators were significant (P < 0.001 and P = 0.001 respectively). A plasma calcitonin precursor concentration of more than 160 fmol/ml on admission was highly accurate (94 per cent) in predicting the development of septic complications and death.

CONCLUSION

The assay of plasma calcitonin precursors on the day of admission to hospital has the potential to provide a more accurate prediction of the severity of acute pancreatitis than the APACHE II scoring system.

Antibiotic therapy for prophylaxis against infection of pancreatic necrosis in acute pancreatitis

BACKGROUND

Acute pancreatitis is a common acute abdominal emergency which lacks specific therapy. In severe attacks, areas of the pancreas may become necrotic. The mortality risk rises to >40% if sterile necrosis becomes superinfected, usually with gut derived aerobic organisms. Experimental and clinical studies indicate a window of opportunity of 1-2 weeks, when superinfection, and thus high-risk surgical debridement, may be prevented by administering systemic antibiotics to 'sterilise' tissues adjacent to necrotic areas. There are theoretical risks of encouraging antibacterial resistance and opportunistic fungal infections.

OBJECTIVES

To determine the effectiveness and safety of prophylactic antibiotic therapy in patients with severe acute pancreatitis who have developed pancreatic necrosis.

SEARCH STRATEGY

MEDLINE, EMBASE, and the Cochrane Library were searched. We also examined other sources including Conference Abstracts (published and unpublished data).

SELECTION CRITERIA

Randomised controlled trials (RCT) were sought using the search strategy detailed below. No linguistic limitations were applied. RCTs were selected in which antibacterial therapy was evaluated in patients with severe acute pancreatitis associated with pancreatic necrosis proven by intravenous contrast-enhanced computed tomography (CT). No linguistic limitations were applied. Searching was undertaken initially in November 2001 and updated in March 2003.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data from trial publications independently, concerning rates for the primary end-points: with respect to: all cause mortality and rates of infection of pancreatic necrosis (proven by microbiological examination of fine needle aspirate or operative specimens). In addition, secondary end-points included peri-pancreatic sepsis, remote sepsis (respiratory, urinary, central venous line sources), operative rates, length of hospital stay, adverse events including the incidence of drug resistant microorganisms and opportunistic fungal infection.

MAIN RESULTS

It was possible to evaluate mortality in all four included studies, and it demonstrated a survival advantage for antibiotic therapy (Odds ratio 0.32, p=0.02). Pancreatic sepsis (infected necrosis) was also measurable in all four studies and showed an advantage for therapy (Odds ratio 0.51, p=0.04). Extra-pancreatic infection could be evaluated in three studies, but showed no significant advantage for therapy (Odds ratio 0.47, p=0.05).Operative treatment data was available in three studies, but surgery rates were not significantly reduced (Odds ratio 0.55, p=0.08). Fungal infections showed no strongly increased preponderance with therapy (Odds ratio 0.83, p=0.7), but there were no data on infection with resistant organisms. Length of hospital stay could only be evaluated in two studies and was not significantly different. Sub-group analyses planned for the influence on outcome measures of the antibiotic regimen, the time of commencement of therapy in relation to symptom onset and/or hospitalisation, duration of therapy, and aetiology could not be performed as no data were available.

REVIEWER'S CONCLUSIONS

Despite variations in drug agent, case mix, duration of treatment and methodological quality (especially the lack of double blinded studies), there was strong evidence that intravenous antibiotic prophylactic therapy for 10 to 14 days decreased the risk of superinfection of necrotic tissue and mortality in patients with severe acute pancreatitis with proven pancreatic necrosis at CT. Further studies are required to confirm all of the benefits suggested (in particular the need for operative debridement), to provide more adequate data on adverse effects, to address the choice of antibacterial agents and effects of varying duration of therapy, and whether outcome is related to aetiology.

Does pneumatic dilatation affect the outcome of laparoscopic cardiomyotomy?

BACKGROUND

Controversy surrounds the choice of laparoscopic cardiomyotomy as the primary treatment for achalasia or a second-line treatment following the failure of nonsurgical treatment. Laparoscopic cardiomyotomy can be more difficult technically following pneumatic dilatations. The aim of this study was to compare the outcome obtained with primary laparoscopic cardiomyotomy to that achieved when the procedure is performed following failed pneumatic dilatation.

METHODS

Laparoscopic cardiomyotomy was performed in seven patients following a median of four pneumatic dilatations (group A) and in five patients as their primary treatment (group B). Outcome was measured using manometry, a modified DeMeester symptom scoring system, and a quality-of-life questionnaire.

RESULTS

There were no significant differences between groups A and B in sex, age, preoperative modified DeMeester score, or mean barrier pressure. Six of seven group A patients had evidence of periesophageal and submucosal fibrosis at surgery, but this condition was not seen in group B patients. The operative time was slightly longer in group A patients. There was no difference in complication rates (one primary hemorrhage in group A and one esophageal perforation in group B), and both groups had a significantly improved modified DeMeester score at 6 weeks and at long-term follow-up (median, 26 months). Eleven of 12 patients said that they would choose laparoscopic cardiomyotomy as their primary treatment if newly diagnosed with achalasia.

CONCLUSIONS

Laparoscopic cardiomyotomy is safe and effective as a primary or second-line treatment following pneumatic dilatations in patients with achalasia.

Laparoscopic cholecystectomy in morbidly obese patients

BACKGROUND

Morbid obesity is generally regarded as a risk factor for laparoscopic cholecystectomy due to increases in operative time, morbidity, and conversion rate to open cholecystectomy. The aim of this study was to evaluate the feasibility and outcome of laparoscopic cholecystectomy (LC) in morbidly obese patients.

METHODS

A total of 864 consecutive patients underwent LC at our institution between 1990 and 1997. This series represents a continuing policy of LC for all comers. Data were collected prospectively. There were 659 nonobese (NO: BMI 40 kg/m2). Laparoscopic bile duct exploration was performed in 28 (4.2%), nine (4.8%), and one (5.9%) patients, respectively.

RESULTS

Obesity and morbid obesity were associated with trends toward an increased conversion rate (2.3% NO; 4.3% OB; 5.9% MO), a longer operative time (median, 80, 85, and 107 mins, respectively), greater postoperative morbidity (4.7%, 5.9%, and 11.8%, respectively), and a reduced ability to obtain cholangiography (86.1%, 80.1%, and 71.4%, respectively). None of these differences, however, were statistically significant (c2 test, p > 0.05). Postoperative hospital stay for LC was similar for all three groups (median, 1 day).

CONCLUSION

LC in morbidly obese patients is a safe procedure, but it may be associated with increased operative difficulty and morbidity, as compared with nonobese and obese patients.

Elective laparoscopic cholecystectomy: preoperative prediction of duration of surgery

BACKGROUND

Efficient use of operating time has become a key concern. The aim of this study was to determine preoperative factors that can predict extended duration of operating time (>90 min) for laparoscopic cholecystectomy (LC).

METHODS

Data collected prospectively on 827 consecutive patients who underwent elective LC between 1990 and 1997 were analyzed. Factors evaluated included age, gender; body mass index; comorbidity; duration of symptoms; history of jaundice, pancreatitis, or abdominal surgery; dilated common bile duct or thick-walled gallbladder on ultrasound; preoperative endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic sphincterotomy (ES); and surgeon experience. Univariate and multivariate analyses were performed to identify factors predicting a long operation.

RESULTS

Operating time was longer than 90 min in 276 patients (33%). Predictors of extended operation time were age older than 55 years (odds ratio [OR] = 9.7), preoperative ES (OR = 2.8), and a thick-walled gallbladder on ultrasound (OR = 2.5).

CONCLUSION

These predictors may be useful in planning theater lists and anesthesia management, and in selecting patients for day surgery.

Double blind, randomised, placebo controlled study of a platelet activating factor antagonist, lexipafant, in the treatment and prevention of organ failure in predicted severe acute pancreatitis

BACKGROUND

Platelet activating factor (PAF) is believed to amplify the activity of key mediators of the systemic inflammatory response syndrome (SIRS) in acute pancreatitis, resulting in multiorgan dysfunction syndrome. We tested the hypothesis that a potent PAF antagonist, lexipafant, could dampen SIRS and reduce organ failure in severe acute pancreatitis.

METHODS

We conducted a randomised, double blind, placebo controlled, multicentre trial of lexipafant (100 mg/24 hours intravenously for seven days commenced within 72 hours of the onset of symptoms) involving 290 patients with an APACHE II score >6. Power calculations assumed that complications would be reduced from 40% to 24%. Secondary end points studied included severity of organ failure, markers of the inflammatory response, and mortality rate.

FINDINGS

Overall, 80/138 (58%) patients in the placebo group and 85/148 (57%) in the lexipafant group developed one or more organ failures. The primary hypothesis was invalidated by the unexpected finding that 44% of patients had organ failure on entry into the study; only 39 (14%) developed new organ failure. Organ failure scores were reduced in the lexipafant group only on day 3: median change -1 (range -4 to +8) versus 0 (-4 to +10) in the placebo group (p=0.04). Systemic sepsis affected fewer patients in the lexipafant group (13/138 v 4/148; p=0.023). Local complications occurred in 41/138 (30%) patients in the placebo group and in 30/148 (20%) in the lexipafant group (20%; p=0.065); pseudocysts developed in 19 (14%) and eight (5%) patients, respectively (p=0.025). Deaths attributable to acute pancreatitis were not significantly different. Interleukin 8, a marker of neutrophil activation, and E-selectin, a marker of endothelial damage, decreased more rapidly in the lexipafant group (both p<0.05); however, absolute values were not different between the two groups.

INTERPRETATION

The high incidence of organ failure within 72 hours of the onset of symptoms undermined the primary hypothesis, and power calculations for future studies in severe acute pancreatitis will need to allow for this. Lexipafant had no effect on new organ failure during treatment. This adequately powered study has shown that antagonism of PAF activity on its own is not sufficient to ameliorate SIRS in severe acute pancreatitis

Intraoperative cholangiography during laparoscopic cholecystectomy

BACKGROUND

The routine use of intraoperative cholangiography (IOC) during laparoscopic cholecystectomy remains controversial.

METHODS

A retrospective review of 950 consecutive laparoscopic cholecystectomies performed during an 8-year period was performed. For the first 2 years, IOC was performed selectively, and thereafter routinely.

RESULTS

Attempted in 896 patients, IOC was successful in 734 (82%). Bile duct stones were found in 77 patients (10%), dilated ducts without stones in 47 patients (6%), and anatomic variations in 4 patients (0.5%). There were four (0.4%) minor intraoperative complications related to the IOC, with no consequences for the patients. There were three (0.3%) minor injuries of the bile duct, which were identified with IOC and repaired at the time of cholecystectomy without any consequences for the patients. In two of these patients, the structure recognized and catheterized as the cystic duct was revealed by IOC to be the bile duct. Thus IOC prevented extension to a major common bile duct (CBD) injury.

CONCLUSIONS

Findings show that IOC is a safe technique. Its routine use during laparoscopic cholecystectomy may not prevent bile duct injuries, but it minimizes the extent of the injury so that it can be repaired easily without any consequences for the patient. The prevention of a major bile duct injury makes IOC cost effective.

Routine vs "on demand" postoperative ERCP for small bile duct calculi detected at intraoperative cholangiography. Clinical evaluation and cost analysis

BACKGROUND

The detection of small and often asymptomatic gallbladder calculi within the bile duct at intraoperative cholangiography (IOC) during laparoscopic cholecystectomy (LC) frequently poses a management dilemma. Therefore, we set out to compare the outcomes and costs of two management strategies for small stones that remain in the bile duct after LC-routine postoperative endoscopic retrograde cholangiopancreatography (ERCP) vs observation alone with "on-demand" ERCP.

METHODS

We studied 70 patients with bile duct stones among 922 consecutive patients who underwent LC between 1990 and 1997. Data were collected prospectively. Bile duct calculi were detected in 70 of 705 patients (9.9%) with successful IOC. Of these, 44 patients had large calculi (> or =5 mm in diameter) and were subjected to a laparoscopic common bile duct exploration. The remaining 26 patients had small calculi (<5 mm in diameter); four of them had undergone preoperative endoscopic sphincterotomy and duct clearance and were therefore excluded from analysis. Patients with small duct calculi were assigned, according to individual surgeon policy, to either routine postoperative ERCP (group A, n = 8) or observation (group B, n = 14). ERCP was reserved for those who become symptomatic. The two groups were comparable for age and sex distribution.

RESULTS

No complications developed during the follow-up period in patients assigned to observation, although four became symptomatic and underwent ERCP. In group A, ERCP demonstrated a clear biliary tree in four patients and bile duct calculi in three patients; it failed in one patient. In group B, ERCP demonstrated a clear bile duct in one patient and bile duct calculi in two patients; it also failed in one patient. Endoscopic sphincterotomy and duct clearance were achieved in all patients with demonstrable bile duct calculi at ERCP. There was no morbidity or mortality associated with ERCP. The overall hospital stay was significantly longer in group A than in group B (median 5 vs 1.5 days; p = 0.011); however, the number of outpatient clinic visits was significantly greater in group b (median 3 vs 5.5, p = 0.011). The mean hospital costs, including the costs of hospital stay, readmissions, ERCP, and follow-up, were significantly greater in group A than in group B (mean pound2669 vs pound1508, p = 0.008).

CONCLUSION

A "wait and see" policy of observation alone for patients with small bile duct calculi detected at IOC during LC appears to be safe, and it is more cost-effective than routine postoperative ERCP. ERCP should be reserved for post-LC patients who become symptomatic.

Relaparoscopy for the detection and treatment of complications of laparoscopic cholecystectomy

BACKGROUND

Laparotomy remains the commonest intervention in patients with abdominal complications of laparoscopic surgery. Our own policy is to employ relaparoscopy to avoid diagnostic delay and unnecessary laparotomy. The results of using this policy in patients with suspected intra-abdominal complications following laparoscopic cholecystectomy are reviewed.

METHODS

Data were collected from laparoscopic cholecystectomies carried out by five consultant surgeons in one center. Details of relaparoscopy for complications were analyzed.

RESULTS

Thirteen patients underwent relaparoscopy within 7 days of laparoscopic cholecystectomy for intra-abdominal bleeding (2 patients) or abdominal pain (11 patients). The causes of pain were subhepatic haematoma (1), acute pancreatitis (1), small bowel injury (1), and minor bile leakage (6). In 2 patients no cause was identified. Twelve patients were managed laparoscopically and 1 patient required laparotomy. Median stay after relaparoscopy was 7 days (range 2 to 19).

CONCLUSIONS

Exploratory laparotomy can be avoided by prompt relaparoscopy in the majority of patients with abdominal complications of laparoscopic cholecystectomy.

Laparoscopic treatment of Mirizzi syndrome

Mirizzi syndrome is a rare disorder and remains a surgical challenge. It is generally considered as a contraindication to laparoscopic surgery. Three patients with Mirizzi type II syndrome and two patients with Mirizzi type I syndrome were treated laparoscopically. Partial cholecystectomy with fundus-first dissection of the gallbladder was performed, and closure of the fistula in type II syndrome was achieved over a T-tube. The common bile duct (CBD) was explored in one patient using a choledochoscope through the fistula. The procedure was completed laparoscopically in all five patients. The three patients with type II syndrome had residual CBD stones, which were associated with significant morbidity and mortality. Laparoscopic treatment of Mirizzi type I syndrome is technically feasible and safe. For Mirizzi type II syndrome, laparoscopic CBD exploration is demanding and experience, skill, and the full spectrum of modern technology are required.

Randomized comparison between low-pressure laparoscopic cholecystectomy and gasless laparoscopic cholecystectomy

BACKGROUND

Laparoscopic cholecystectomy using low-pressure pneumoperitoneum (8 mmHg) minimizes adverse hemodynamic effects, reduces postoperative pain, and accelerates recovery. Similar claims are made for gasless laparoscopy using abdominal wall lifting. The aim of this study was to compare gasless laparoscopic cholecystectomy to low-pressure cholecystectomy with respect to postoperative pain and recovery.

METHODS

Thirty-six patients were randomized to low-pressure or gasless laparoscopic cholecystectomy using a subcutaneous lifting system (Laparotenser).

RESULTS

The characteristics of the patients were similar in the two groups. The procedure was completed in all patients in the low-pressure group, but two patients in the gasless group were converted to pneumoperitoneum. There were no significant differences in postoperative pain and analgesic consumption, but patients in the gasless group developed shoulder pain more frequently (50% vs 11%, p < 0.05). Gasless operation took longer to perform (95 vs 72.5 min, p = 0.01).

CONCLUSIONS

Gasless and low-pressure laparoscopic cholecystectomy were similar with respect to postoperative pain and recovery. The gasless technique provided inferior exposure and the operation took longer, but the technique may still have value in high-risk patients with cardiorespiratory disease.

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.

Micropuncture laparoscopic cholecystectomy

BACKGROUND

Laparoscopic cholecystectomy (LC) significantly reduces the discomfort and disability typically associated with open cholecystectomy, but there is still room for improvement.

METHODS

In order to further reduce the trauma of access, we have introduced a technique of micropuncture laparoscopic cholecystectomy (MPLC) that utilizes three 3-mm cannulae in addition to the standard 10-mm cannula at the umbilicus. MPLC was performed in 25 patients (median age, 52 years; m/f, three of 22) with symptomatic cholelithiasis.

RESULTS

The operation was completed in all patients. The median duration of surgery was 75 min (range, 45-180). Sixteen patients were discharged the same day and nine patients the next day. All the patients had an uncomplicated recovery. Only eight patients requested postoperative analgesia while in hospital. Micropuncture exploration of the bile duct was carried out in one patient.

CONCLUSIONS

MPLC is a feasible and safe technique that appears to improve on the benefits of LC; it makes the operation even more feasible as a day-surgery procedure.

Laparoscopic surgery combined with preservation of the spleen for distal pancreatic tumors

BACKGROUND

Laparoscopic distal pancreatectomy combined with spleen salvage by preservation of the splenic vessels has been described in selected patients with islet cell tumors.

METHODS

Laparoscopic resection of the left side of the pancreas with spleen preservation on the vasa brevia was attempted in six consecutive patients.

RESULTS

Four distal pancreatectomies with spleen preservation were completed laparoscopically. There were two conversions to laparotomy. The median operating time was 300 min (range, 240-360). There was no mortality, but two patients developed a pancreatic fistula. The median postoperative hospital stay was 34.5 days (range, 5-60). All the patients remain well at a median follow-up of 30 months (range, 22-41).

CONCLUSIONS

Minimally invasive surgery for distal pancreatic tumors is feasible and appropriate for most benign tumors. The spleen can be safely preserved laparoscopically on its blood supply from the short gastric vessels. The operative technique and especially the closure of the pancreatic stump need further study.

Laparoscopic cholecystectomy after pancreatic debridement

BACKGROUND

Pancreatic debridement is a lifesaving operation in patients with severe acute pancreatitis and pancreatic or peripancreatic necrosis. Even in the presence of gallstones, cholecystectomy may be avoided during the procedure, but definitive treatment of the stones is needed at a later stage.

METHODS

Five patients (median age 58 years) underwent laparoscopic cholecystectomy, at a median time interval of 15 months, after pancreatic debridement via a dome-shaped upper abdominal incision for severe acute pancreatitis. The use of alternative methods for primary access, additional cannulae to enable division of adhesions, the harmonic scalpel, and the fundus first technique made the laparoscopic approach possible and safe.

RESULTS

The median operating time was 130 min. Four patients were discharged home the first or second postoperative day. One patient required a "mini-laparotomy" for drainage of a periumbilical hematoma and was discharged on the 13th day.

CONCLUSIONS

Laparoscopic cholecystectomy can be considered an effective and safe approach for the treatment of gallstones in patients who have undergone pancreatic debridement.

Assessment of severity and prognosis in acute pancreatitis

Assessment of severity and prognosis in acute pancreatitis was originally driven by clinicians' needs for the prediction of outcome, together with the requirement of researchers for objective measurement of severity. Evaluation of the multitude of competing systems has been hindered by varying definitions of severity, incomplete reporting and a lack of comparative data. Although clinical assessment, Ranson and Glasgow scores remain predominant, the recent literature reflects how needs have changed, as a result of improved understanding of the biological events underlying attacks and technological advances. The Atlanta International Symposium should provide a suitable framework for progress.

T2-weighted and dynamic enhanced MRI in acute pancreatitis: comparison with contrast enhanced CT

The purpose of this study was to compare T2-weighted and dynamic contrast enhanced MRI with contrast enhanced CT in patients with severe acute pancreatitis. Thirty-two patients were examined using axial T2-weighted spin-echo imaging (TR 1801, TE 15/90) and a multi-slice rapid gradient-echo sequence (TR 135, TE 4, FA 80 degrees) (FLASH) in axial and coronal planes. Fifteen 5 mm axial slices at 10 mm intervals were acquired during a single breath-hold of 19 s before, and at 10 and 40 s after a bolus injection of Gd-DTPA. Additional FLASH images in the coronal plane were obtained 2 min after injection of contrast medium. MR was compared with contemporary enhanced CT by two blinded observers who scored pancreatic viability and the content of intra and extra-pancreatic fluid collections. The presence of gas, calcification and haemorrhage was noted. Abnormalities in adjacent organs, evidence of vascular occlusion and indicators of aetiology were also recorded. MR and CT were concordant in distinguishing viable pancreatic tissue from areas of necrosis. MR appeared to be more effective than CT in characterizing the content of fluid collections and in demonstrating gall stones, although CT remains superior in detecting flecks of gas and calcification. MR carries some advantages over CT and can be regarded as an alternative primary technique in patients with severe pancreatitis.

Circulating mediators in acute pancreatitis as predictors of severity

The case mortality for acute pancreatitis in the UK has remained largely unchanged, at just under 10% for the last 30 years. This is despite improvements in intensive therapy, radiology and surgical interventions. Acute pancreatitis also remains unpredictable. Organ system failure and pancreatic collections may develop either suddenly, or insidiously, and thus go undetected. Reducing mortality depends on better understanding of pathophysiology and more specific therapeutic approaches, but prognostic systems for the early identification of severe attacks may improve the success of current supportive therapies. Prognostic systems are also useful to compare clinical series and stratify severity in therapeutic trials. The multiple criteria of Ranson and Imrie predominate, but offer limited accuracy, involve delay, are cumbersome, and provide a one-off overall prediction. Internationally agreed definitions of complications demand accurate risk assessment for individual complications, while serial monitoring of severity is needed to assess progress and to detect subtle changes after therapeutic intervention. Laboratory methods now provide equal, or improved, accuracy and speed compared to traditional criteria, and may be repeated serially. Growing knowledge of the systemic inflammatory response syndrome (SIRS) and the availability of response modifiers suggests that inflammatory mediators may prove to be the most useful and accurate means of assessment of severity.

Impaired mononuclear phagocyte function in patients with severe acute pancreatitis: evidence from studies of plasma clearance of trypsin and monocyte phagocytosis

Activated proteases in plasma are complexed by alpha 2-macroglobulin. Although the complexes retain peptidase activity, they are usually eliminated promptly by mononuclear phagocytes. In severe acute pancreatitis, almost 30% of plasma alpha 2-macroglobulin becomes complexed, suggesting impaired clearance. In the present study, plasma [methyl-14C]trypsin clearance and monocyte phagocytosis were investigated. Attacks complicated by major organ-system failure, pancreatic pseudocyst, abscess, or necrosis were graded severe (median Ranson score 5.5). Plasma [methyl-14C]trypsin half-life was significantly increased in severe attacks (N = 7, median 21.1 min), compared to mild attacks (N = 14, median 15.4 min, P < 0.05) and healthy controls (N = 4, median 10.8 min, P < 0.02). Monocyte phagocytosis was significantly lower in severe attacks (N = 9, median 3.6%) compared to mild attacks (N = 20, median 20.8%, P < 0.01) and healthy controls (N = 8, median 26.9%, P < 0.01). Plasma [methyl-14C]trypsin half-life and monocyte phagocytosis were significantly inversely correlated (r = -0.51, P < 0.01). Impaired clearance of circulating trypsin in acute pancreatitis is potentially deleterious but may be reversed by stimulating mononuclear phagocytes.

Dynamic contrast enhanced computed tomography: a precise technique for identifying and localising pancreatic necrosis

OBJECTIVE

To evaluate dynamic contrast enhanced computed tomography for detecting and localising pancreatic necrosis in acute pancreatitis.

DESIGN

Prospective evaluation with blind reporting of scans.

SETTING

Single teaching hospital.

PATIENTS

60 Consecutive patients with acute pancreatitis suspected to have pancreatic necrosis because of major organ system failure (13); slow recovery five to seven days after admission with raised scores on the acute physiological and chronic health evaluation (APACHE-II) system (27); or findings on previous ultrasonography or computed tomography (20).

MAIN OUTCOME MEASURE

Pancreatic necrosis proved histologically--that is, greater than 30 g necrotic tissue debrided at laparotomy (for life threatening sepsis or peritonitis) or necropsy.

RESULTS

Dynamic computed tomography correctly localised pancreatic necrosis in 11 patients (confirmed at laparotomy in nine and at necropsy in two). Of nine patients with low enhancement of peripancreatic tissues alone, eight recovered after conservative management; necropsy confirmed viable pancreas and necrosis of peripancreatic fat in one patient. Of 40 patients with normal contrast enhancement, none required laparotomy to debride pancreatic necrosis.

CONCLUSION

Dynamic contrast enhanced computed tomography seems to be a safe and accurate method of identifying and localising pancreatic and peripancreatic necrosis, which cannot be predicted accurately by conventional imaging techniques.

APACHE-II score for assessment and monitoring of acute pancreatitis

The value of the Acute Physiology and Chronic Health Enquiry (APACHE-II) score, the Simplified Acute Physiology score, and the Medical Research Council (MRC) sepsis score were compared with clinical assessment and Ranson and Imrie scores in the evaluation and monitoring of acute pancreatitis in 290 attacks. Attacks were graded mild (231) if uncomplicated, or severe (59) when major organ failure or a pancreatic collection occurred. Only APACHE-II scores were available at the time of admission; they correctly predicted outcome in 77% of attacks and identified 63% of severe attacks, compared with 44% achieved by clinical assessment. After 48 h, APACHE-II was most accurate, and correctly predicted outcome in 88% of attacks, compared with 69% for Ranson and 84% for Imrie scores. APACHE-II predicted 73% of pancreatic collections at 48 h, compared with 65% for Ranson and 58% for Imrie scores. In acute pancreatitis, APACHE-II may facilitate rapid selection of patients for intensive therapy or clinical trials, improve comparison between groups of patients, and indicate that a pancreatic collection is probable.

Debridement and closed cavity irrigation for the treatment of pancreatic necrosis

Pancreatic and peripancreatic debridement combined with a closed cavity system of drainage was used to manage necrotic sequelae of severe acute pancreatitis in 14 patients. Intravenous contrast-enhanced computed tomography, or latterly incremental dynamic computed tomographic angiography, accurately detected and localized necrotic tissue. Operation was delayed where possible to permit demarcation of the necrotic area and the development of a 'capsule' of inflammatory tissue. A retrocolic route of access to the necrotic area was used in nine cases, and purpose-made silicone elastomer tubes with an outside diameter of 20 mm were positioned so that drainage was assisted by gravity when the patient was supine. The cavity was irrigated with saline (initially 2 litres daily), and in the last seven patients Trasylol was included in the irrigation fluid (5 x 10(6) kallidinogenase inactivator (KI) units/litre) for the first postoperative week. Three elderly patients died (mean age 72 years) but all patients aged less than 68 years survived. Planned reoperation was carried out in two patients, but further reoperations were not required in the remaining 11. Drainage tubes were removed when contrast studies showed the cavity to be small and superficial; the median duration of drainage was 28 days. Although sinograms demonstrated fistulae between cavity and small bowel (n = 4) or small bowel and colon (n = 2), no clinical problems resulted and all closed spontaneously. Closed drainage may be as effective as techniques of marsupialization, but avoids the need for frequent relaparotomy.

Intra-peritoneal aprotinin therapy for acute pancreatitis. Preliminary pharmacodynamic studies

In acute pancreatitis a toxic exudate accumulates within the peritoneal cavity, which contains activated pancreatic proteinases. Peritoneal lavage removes the exudate effectively, washing it away with large volumes of saline solution, but is of unproven therapeutic value and may have deleterious effects. These may be avoided by combining lower volume peritoneal washouts with intra-peritoneal installation of a proteinase inhibitor, although therapeutic effectiveness may be compromised by systemic absorption depending on the inhibitor selected. This latter effect was studied in fifteen patients with acute pancreatitis, treated by simple peritoneal washout and bolus intra-peritoneal administration of aprotinin (Trasylol) solution.