René Laugier

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

BACKGROUND & AIMSnThe 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.nnnMETHODSnHealthy 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.nnnRESULTSnAlthough 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.nnnCONCLUSIONSnAlthough 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.

Effects of Lansoprazole on Human Gastric Lipase Secretion and Intragastric Lipolysis in Healthy Human Volunteers

Background: Lansoprazole is a potent proton-pump inhibitor (PPI) of parietal cells, which reduces the secretion of gastric acid. Although human gastric lipase (HGL) is produced only by the chief cells of the stomach, the possibility that interactions may occur between lansoprazole and HGL has never been addressed so far in humans. The aim of this study was therefore to quantify the effects of lansoprazole on HGL secretion and intragastric lipolysis during the ingestion of test meals by healthy human volunteers. Methods: Six healthy volunteers were intubated twice with a gastric and a duodenal tube, before ingesting a standard liquid test meal alone (–PPI experiments) and after 7 days of lansoprazole treatment (+PPI experiments). The HGL concentration was assessed in gastric and duodenal samples by measuring the lipase activity using a pH-stat, and the lipolysis products were quantified by performing thin layer chromatography. The level of intragastric lipolysis was defined as the percentage acyl chains released from the meal triglycerides. The pyloric outputs of HGL and lipolysis products were calculated, based on the use of a non-absorbable marker added to the meal. Results: The pH of the gastric contents was significantly higher in the +PPI experiments than in the –PPI experiments (p < 0.05), since mean values of 4.3 ± 2.5 and 2.2 ± 1.6, respectively, were recorded at the end of the gastric emptying of the meal. The HGL concentrations recorded during the meal were found to be higher in the experiments with lansoprazole (p < 0.05) than in those without lansopra- zole, but the HGL secretion levels (–PPI: 15.4 ± 8.0 mg; +PPI: 19.0 ± 7.4 mg) and the intragastric lipolysis (–PPI: 24.0 ± 8.0%; +PPI: 23.6 ± 6.8%) were not significantly affected by lansoprazole (p > 0.05 in both cases). Conclusion: Lansoprazole affected neither the HGL secretion nor the intragastric lipolysis levels, although an increase was observed in the intragastric pH at the end of the gastric emptying of the meal. The HGL concentration increased, however, due to the decrease in the acid secretion process, resulting in less diluted gastric contents.

Advantage of Expressing the Variations in Some Digestive Parameters as a Function of Gastric Emptying instead of Time

Background/Aim: Gastric emptying is a major cause of variability when studying gastrointestinal parameters as a function of time. Here, we investigate whether the parametric variability could be reduced by running experiments on a gastric emptying basis rather than on a time basis. Methods: Healthy volunteers were intubated with gastric and duodenal tubes and were given a liquid meal containing polyethylene glycol to monitor gastric emptying. Gastric pH and human gastric lipase (HGL) concentrations were measured. Their variations were plotted as a function of either time or gastric emptying (%). In both cases, mean curves of variation were established by polynomial regression. Results: When time was the variable used, the overall deviation of the experimental values from the values given by the best-fitting curve was high (χ2 = 33 for gastric pH; χ2 = 1,744 for HGL), and the individual deviations increased with time. When gastric emptying was the variable used, the overall deviation of the experimental values from the values given by the best-fitting curve was much lower (χ2 = 10 for gastric pH; χ2 = 642 for HGL). Conclusions: Expressing gastric pH or HGL concentration as a function of gastric emptying instead of time makes it possible to reduce the individual variability. This new type of data analysis may be of a general interest to observe specific variations of gastrointestinal parameters induced by drugs, hormones, and meals, and that might be masked by the large intrinsic variability induced by gastric emptying.

Endoscopic ductal drainage may avoid resective surgery in painful chronic pancreatitis without large ductal dilatation.

SummaryConclusion. Endoscopic stenting treatment, in cases of chronic pancreatitis unsuitable for decompressive surgery, appears to be safe and efficient. Perfect anatomical results are only obtained if large stents are used after balloon dilatation.Background. Decompressive surgery in cases of painful chronic pancreatitis is only feasible if the main pancreatic duct exceeds approx 8 mm over a sufficient length. When those anatomical changes are not present, surgery must be resective. This study evaluates the results of endoscopic stent drainage and decompression of painful chronic pancreatitis without large dilatation of the main pancreatic duct.n Methods. Sixteen of our chronic pancreatitis patients were included in this study. They presented a mean of 5.3 episodes of pain in the 6 mo before treatment. Decompressive surgery was not possible because of a mean pancreatic duct diameter of 5.8 mm. Stents were 7F in eight patients and 12F in the other eight. They were left in the duct after endoscopic dilation for 9.5±1.0 mo.n Results. During stenting we observed two early obstructions and seven episodes of pain. All cysts disappeared and stenosis of the duct disappeared anatomically in six cases, was improved in four, but persisted in six. During follow-up, two episodes of mild pain were recorded. No cysts reappeared. Complete disappearance of stenosis was only observed in patients whose pancreatic duct was equipped with a 12F stent (P<0.02).

Critical evaluation of a specific ELISA and two enzymatic assays of pancreatic lipases in human sera

Background and Aims: Human pancreatic lipases (HPL) include the classical HPL, and two related proteins known as pancreatic lipase-related proteins 1 and 2 (HPLRP1 and 2). The aim of this study was to develop an ELISA for specifically quantifying the classical-HPL level in sera of patients with and without pancreatic disorders. Methods: The specific activity of various human (including classical-HPL) and microbial lipases was measured using Lipa Vitros and potentiometric (pH-stat) assays. A double sandwich ELISA was also set up, using an anti-classical-HPL polyclonal antibody and a biotinylated monoclonal antibody (mAb 146-40) specific to the classical-HPL. Sera (n = 53) were collected from patients with and without pancreatic disorders. The lipase concentration was deduced from the measured lipolytic activity and compared with the corresponding classical-HPL concentration, measured with the ELISA. Results: Both the purified HPLRP2 and 3 lipases of microbial origin were found to have a significant and unexpected lipolytic activity under the standard Lipa Vitros assay, whereas the ELISA test developed in the present study was found to be specific for the classical-HPL, due to the absence of cross-reactivity between mAb 146-40, HPLRP1 and HPLRP2. The efficiency of the ELISA was assessed in terms of its reproducibility and accuracy. The lower detection limit of classical-HPL was found to be 0.03 µg/l. A good correlation was found to exist between the lipase concentrations obtained in the ELISA, pH-stat and Lipa Vitros tests, in both the control and pathological groups. Conclusion: This is the first time a specific method of measuring classical-HPL in human serum has been proposed. Using this ELISA, we established with the 53 sera selected in the present study, that the Lipa Vitros assay as well as the pH-stat assay were mostly detecting classical pancreatic lipase. However, it is possible that other lipases such as HPLRP2 or lipases of microbial origin, present in some pathological sera, may well interfere with the Lipa Vitros assay.

Sphincter of Oddi Manometry Paradoxical Response to Secretin But Not to CCK in Alcoholic Patients with No Pancreatic Disease

SummaryConclusion. In chronic alcohol abusers with no pancreatic disease, secretin was found to induce a paradoxical spasmodic response in the sphincter of Oddi (SO) instead of the relaxation observed in controls. Cerulein, on the contrary, had a normal relaxing effect on the SO.Background. We previously reported SO dyskinesia in cases of chronic pancreatitis. Here we investigated whether chronic alcohol consumption may have contributed to the genesis of this dyskinesia.Methods. SO and main pancreatic duct pressures were recorded endoscopically with a dual electronic pressure sensor in 27 chronic alcohol abusers and compared with the values obtained in 15 normal controls. These pressures were recorded both in the basal state and after applying hormonal stimulation by injecting either secretin (1 CU/kg) or cerulein (75 ng/kg).Results. Cerulein relaxed the SO in both the controls and the chronic alcohol abusers, whereas it transiently enhanced the main pancreatic duct (MPD) pressure. Secretin induced a wave of MPD hyperpressure (+15.4±3.0 mm Hg) in both groups of subjects, but in the alcoholic group, instead of relaxing SO, it significantly enhanced the amplitude of phasic contractions (+32.6±8.4 mm Hg). The SO basal pressure was also paradoxically enhanced by secretin in the alcoholic patients (28.8±8.2 vs 10.1±2.4 mm Hg).

Development of an indirect method for measuring porcine pancreatic lipase in human duodenal fluid

Patients with exocrine pancreatic insufficiency are usually treated with porcine pancreatic enzymes but the bioavailability of these enzymes in the gut remains a matter of discussion. In order to determine the duodenal availability of porcine pancreatic lipase (PPL) present in pancreatic extracts (PE) taken orally, we developed a method for quantifying PPL in samples containing both PPL and human pancreatic lipase (HPL). Total pancreatic lipase activity measurements using the pH-stat technique and tributyrin as substrate were combined with an HPL-specific ELISA. Based on the known specific activity of the purified HPL, its activity was deduced from the ELISA measurements, and the PPL activity was obtained by subtracting the HPL activity from the total pancreatic lipase activity. This assay was established and validated using various samples containing pure PPL and recombinant HPL or PE, mixed or not with human duodenal juice. Samples collected in vivo from patients treated with PE were also tested. It was found that PPL did not affect the HPL ELISA, and the indirect PPL assay gave a measurement accuracy of 6.6% with the samples containing pure PPL and 10% with those containing PE. This assay was also used successfully to discriminate between PPL and the endogenous HPL present in the duodenal contents of patients with severe pancreatic insufficiency treated with PE. This method might provide a useful means of assessing the availability of PEs at their site of action, in the absence of a PPL-specific ELISA.