Hyperlipidemia intensifies cerulein-induced acute pancreatitis associated with activation of protein kinase C in rats

AIM: To investigate the effects of hyperlipidemia on acute pancreatitis (AP) and the possible mechanisms. METHODS: Rat models of hyperlipidemia and AP were established by Triton WR1339 and cerulein respectively. Human albumin was used to treat AP complicated by hyperlipidemia. In each group, we compared the histological score, volume of ascites, ratio of pancreatic wet/dry weight, serum amylase (AMY) and pancreatic acinar cell apoptosis. The level of protein kinase C (PKC) membrane translocation in pancreatic tissue was detected by Western blot. RESULTS: In the hyperlipidemia model established by Triton WR1339, triglyceride (TG) increased remarkably and reached its peak 6 h after injection, and most rats developed mild acute pancreatitis. Histological score, volume of ascites, ratio of wet/dry weight and serum AMY in AP animals with hyperlipidemia were obviously higher than those in AP animals (P < 0.05) and decreased after albumin therapy but not significantly (P > 0.05). Apoptotic cells detected by terminal deoxynucleotidyl transferase-mediated dUTPbiotin nick end labeling (TUNEL) increased in AP animals with hyperlipidemia and did not change distinctly after albumin therapy. PKC membrane translocation level increased in AP animals with hyperlipidemia and decreased remarkably after albumin therapy (P < 0.05). CONCLUSION: Hyperlipidemia may induce AP or intensify pancreatic injury. Albumin therapy can not alleviate pancreatic lesion effectively. PKC activation may be one mechanism by which AP is intensified by hyperlipidemia.     

Functional changes of the exocrine perfused rat pancreas in cerulein-induced pancreatitis.

Functional changes of the exocrine pancreas in cerulein-induced pancreatitis were evaluated with the isolated perfused rat pancreas. In control specimens (n = 7), baseline pancreatic juice volume was 0.23 +/- 0.06 microliter/min and after stimulation with CCK-8 (10(-10) M) and secretin (10(-10) M), it was 2.26 +/- 0.45 microliter/min, and in cerulein-induced pancreatitis specimens (n = 8), the corresponding values were 0.11 +/- 0.03 and 0.23 +/- 0.08 microliter/min. The amylase content in the pancreatic juice (IU/min) was 0.73 +/- 0.15 (baseline) and 7.03 +/- 1.66 (stimulated) in the control specimens, and 0.012 +/- 0.002 (baseline) 0.018 +/- 0.004 (stimulated), in the cerulein-induced pancreatitis specimens. Amylase and lipase concentrations in the portal effluents were significantly higher in the cerulein-induced pancreatitis (481.3 +/- 79.4 IU/ml, 283.7 +/- 47.2 BALB U/ml) than in the control specimens (10.7 +/- 1.8 IU/ml, 8.9 +/- 2.9 BALB U/ml). Using the electron microscope fusion of large vacuoles with lateral plasma membrane was observed in cerulein-induced pancreatitis. In cerulein-induced pancreatitis, normal secretion was markedly decreased, and the lateral secretion was suggested to result in the elevation of pancreatic enzyme levels in portal effluents.     

Hyperlipaemia intensifies the course of acute oedematous and acute necrotising pancreatitis in the rat.

BACKGROUND--Serum triglyceride concentrations higher than 10 to 20 mmol/l are probably a risk factor for developing acute pancreatitis in humans. AIMS--To therefore analyse the influence of hyperlipaemia on the course of acute oedematous and acute necrotising pancreatitis in rats. SUBJECTS--Male Wistar rats were used in all experiments. METHODS--Six different groups of animals were used: two groups without pancreatitis (controls), two with acute oedematous pancreatitis, and two with acute necrotising pancreatitis. One group from each pair was treated with Triton WR 1339, which induces endogenous hyperlipaemia. Blood samples were taken from all subjects to measure triglyceride, cholesterol, amylase, and lipase. Pancreatic tissue samples were taken and the degree of pancreatic damage was judged microscopically. RESULTS--In the control groups no significant changes occurred, either in serum enzyme activities or in histology. The hyperlipaemic subgroup of animals with acute oedematous pancreatitis developed significantly higher (p < 0.001) serum amylase activities and a greater degree of histological damage (p < 0.01) than the animals of the non-hyperlipaemic acute oedematous pancreatitis group. In the animals with necrotising pancreatitis, serum lipase activity and the histological degree of pancreatic damage were significantly higher in the hyperlipaemic animals than in the non-hyperlipaemic animals. CONCLUSION--This study shows that hyperlipaemia intensifies the course of acute oedematous and acute necrotising pancreatitis in rats.     

Chronic alcohol consumption intensifies caerulein-induced acute pancreatitis in the rat

Rats were chronically fed either an ethanol-containing diet (36% of total calories derived from alcohol) or a pair-fed, control diet (no alcohol) for 8 wk, and acute pancreatitis (AP) was subsequently induced by a 3-h iv infusion of caerulein (CR) at a dose of 5 μg/kg/hr. CR-induced AP in control rats (no alcohol) was characterized by a significant elevation in serum lipase content, pancreatic interstitial edema, infrequent occurrences of karyorrhexis, and the appearance of vacuoles in acinar cells. Chronic feeding of the ethanol diet followed by treatment with CR resulted in increases in serum lipase content, interstitial edema, karyorrhexis, and acinar vacuolization that were significantly greater than that seen in rats fed the control diet and treated with CR. It is concluded that chronic ethanol intake in the rat intensifies AP that is subsequently induced by CR.     

Repetitive cerulein-induced pancreatitis and pancreatic fibrosis in the rat.

The effect of repetitive inductions of pancreatitis by supramaximal doses of cerulein on pancreatic morphology and collagen content was studied in the rat. Pancreatitis was induced nine times at intervals of about 20 days; 3 days after the last injection of cerulein, pancreatitis was still observed, as indicated by pancreatic weight loss, increase of protein-bound hydroxyproline content, acinar-cell destruction, cellular infiltration, and deposition of collagen fibers. However, 6 weeks later, no differences in the parameters mentioned above were observed between control and cerulein-treated animals. Thus, repetitive induction of pancreatitis in the rat, according to the experimental protocol we used, did not result in pancreatic fibrosis.     

Chronic alcohol consumption intensifies caerulein-induced acute pancreatitis in the rat.

Rats were chronically fed either an ethanol-containing diet (36% of total calories derived from alcohol) or a pair-fed, control diet (no alcohol) for 8 wk, and acute pancreatitis (AP) was subsequently induced by a 3-h i.v. infusion of caerulein (CR) at a dose of 5 micrograms/kg/hr. CR-induced AP in control rats (no alcohol) was characterized by a significant elevation in serum lipase content, pancreatic interstitial edema, infrequent occurrences of karyorrhexis, and the appearance of vacuoles in acinar cells. Chronic feeding of the ethanol diet followed by treatment with CR resulted in increases in serum lipase content, interstitial edema, karyorrhexis, and acinar vacuolization that were significantly greater than that seen in rats fed the control diet and treated with CR. It is concluded that chronic ethanol intake in the rat intensifies AP that is subsequently induced by CR.     

Failure of secretin to prevent or ameliorate cerulein-induced pancreatitis in the rat

Infusion of supramaximal concentrations of the synthetic pancreozymin analog cerulein induces acute edematous pancreatitis in the rat. Vacuolization and necrosis of acinar cells is paralleled by an almost complete reduction of pancreatic secretion from the cannulated duct. Preinfusion or coinfusion of synthetic secretin slightly increases pancreatic volume and protein secretion. This effect is only transient, and is always overcome by the actions of cerulein. Secretin does not prevent or improve the cellular destruction of the acinar cells. The results suggest that secretin has no beneficial effect on hormone-induced pancreatitis.     

Activation of proteases in cerulein-induced pancreatitis

The activation of zymogen proteases and lysosomal enzyme cathepsin B in the pancreas was investigated in cerulein-induced pancreatitis in rats. Acute pancreatitis was induced by two intraperitoneal injections of 40 micrograms/kg of body weight of cerulein at intervals of 1 h. After the first cerulein injection, the active trypsin and elastase contents in the pancreas tissues significantly increased, and reached the highest level at 3 h after the first injection, followed by peaks at 5 h in the serum amylase and lipase levels and the pancreas wet weight. Cathepsin B contents in pancreas tissues showed a parallel increase with active zymogen enzymes during the first 3 h of pancreatitis. These findings may suggest that the intracellular activation of trypsinogen is an important step in the development of cerulein-induced acute pancreatitis and that cathepsin B plays a role in the activation of trypsinogen in pancreatic acinar cells.     

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.     

Endogenous hypertriglyceridemia in a nonobese rat model: plasma lipoproteins and dietary sensitivity

Sprague-Dawley male rats from the Ivanovas-Sieve colony (IVA-SIV) show higher plasma triglyceride levels compared to the standard Charles River (CR) rats. The triglyceride enrichment occurs primarily in the very-low-density lipoproteins (VLDL), otherwise of a normal % composition, suggesting that the number of particles is increased, rather than their triglyceride (TG) content. High-density lipoprotein (HDL) particles, corresponding to HDL1, appear to be increased in the IVA-SIV rats, as confirmed by rate-zonal ultracentrifugation. The apoprotein composition of isolated lipoproteins (apo B content and isoelectric focusing pattern), does not differ in the two strains. The IVA-SIV rats are remarkably more TG inducible, compared to the standard CR. This can be shown with fructose loading and with a cholesterol-cholic acid diet. The plasma TG increase, after Triton administration, indicative of the VLDL-TG production, is fourfold higher in the IVA-SIV, compared to the CR rats. These findings provide evidence for some similarities between the IVA-SIV rat and human endogenous hypertriglyceridemia, and suggest an increased TG biosynthesis in this model.     

高甘油三酯血症对大鼠急性胰腺炎模型中胰腺导管上皮细胞间紧密连接的影响研究

目的研究高甘油三酯血症(hypertriglyceridemia,HTG)对大鼠急性胰腺炎(acute pancreatitis,AP)模型胰腺组织细胞间紧密连接(tight junctions,TJs)的影响。方法48只4周龄雄性SD大鼠随机分成普通饲养组(24只)和高脂饲养组(24只),4周后普通饲养组随机分为C组和AP组,高脂饲养组随机分为HTG组和高甘油三酯血症急性胰腺炎(HTGP)组。AP组和HTGP组经腹腔注射雨蛙肽建立AP模型,C组和HTG组经腹腔注射同等剂量的生理盐水,分别于造模24 h、48 h处置大鼠,采用HE染色法观察胰腺病理改变,免疫组织化学法检测胰腺组织中TJs蛋白脂解刺激脂蛋白受体(LSR)、Tricellulin蛋白(TRIC)、ZO-1、occludin、claudin-7定位及表达,透射电镜观察胰腺导管上皮细胞间TJs变化情况。结果高脂饲养组的大鼠血清甘油三酯(triglyceride,TG)较普通饲养组明显升高(P<0.05);HTG组胰腺组织病理评分高于C组(P<0.05),相同时点HTGP组胰腺组织病理评分高于AP组,但差异无统计学意义(P>0.05);HTG组LSR、TRIC表达显著低于C组(P<0.05),AP组和HTGP组的24 h时点LSR、TRIC、occludin、claudin-7表达均低于相应对照组(P<0.05),HTGP组24 h时点LSR和TRIC的表达显著低于AP组的对应时点(P<0.05);透射电镜观察AP组和HTGP组的24 h时点,发现主胰管上皮细胞TJs较C组和HTG组减少、细胞间隙增宽,且HTGP组比AP组的细胞间隙增宽更明显。结论TJs蛋白LSR、TRIC、ZO-1、occludin、claudin-7在HTG及HTGP大鼠胰腺组织中表达较非高脂模型下降,其中以三细胞间紧密连接(tricellular tight junctions,tTJs)蛋白LSR及TRIC下降明显,提示HTG可能减弱胰腺组织的tTJs,进而加重胰腺组织损伤。     

Nonesterified fatty acids in acute cerulein-induced pancreatitis in the rat are they really deleteriousin vivo?

During acute pancreatitis, experimental data obtainedin vitro suggested that pancreatic lipase generates nonesterified fatty acids (NEFA), noxious for acinar cells, by hydrolysis of pancreatic or circulating triglycerides. The purpose of this work was to determine whether experimentally induced high plasma NEFA levels do indeed aggravatein vivo cerulein-induced pancreatitis. Anesthetized Sprague-Dawley rats received cerulein and were simultaneously infused intravenously with either saline or a triglyceride + heparin mixture (TGH) in order to increase the amount of circulating NEFA. Plasma NEFA increased about fourfold (3.02±0.28 µmol/liter) in animals infused with TGH with respect to controls (0.75±0.05 µmol/liter). In rats receiving cerulein + TGH, pancreatic enzyme levels in plasma, ascites, and histological alterations of the pancreas did not differ from those observed in the rats receiving cerulein + saline. There was less macroscopic pancreatic edema (P<0.01) in the cerulein + TGH group than in the cerulein + saline group. Separate infusion of either heparin alone or of triglycerides alone had no effect. We conclude that high levels of circulating NEFA do not aggravate cerulein pancreatitis in rats and may even induce a protective effect.F.P. was the recipient of a scholarship from the Fondation pour la Recherche Médicale (Paris). Partial financial support of the work was provided by the Conseil Scientifique of Faculté X. Bichat and by Association Charles Debray.     

Muscarinic receptors and amylase secretion of rat pancreatic acini during cerulein-induced acute pancreatitis

This study examines the effects of cerulein-induced acute pancreatitis on the secretory response of rat pancreatic acini to carbamylcholine and concentration of acinar muscarinic receptors. Rats were injected subcutaneously every 8 hr with cerulein, 12 g/kg, for two days. They were sacrificed 2 and 4 hr after the first injection, 4 hr after the second and third, and 8 hr after the sixth. By 2 hr after the first injection, carbamylcholine showed decreased potency for stimulating amylase release; decreased potency becomes maximal after the second injection. Four hours after the first injection, carbamylcholine also showed decreased efficacy for causing maximal amylase release. In the course of development of pancreatitis, progressive reductions in muscarinic receptor concentrations were evident from 4 hr after the second injection. Following the complete treatment (8 hr after the sixth injection), no alteration could be observed in the affinity or proportions of each agonist class of muscarinic receptors. These studies indicate that the pancreatic acinar cells still remain functional after acute cerulein-induced pancreatitis, although significant reductions in potency and efficacy of carbamylcholine to cause amylase release and reduced muscarinic receptor concentration occur.     

Subsets associated with developing acute pancreatitis in patients with severe hypertriglyceridemia and the severity of pancreatitis

Background and objectivesHypertriglyceridemia (HTG) is a rare but well-recognized cause for acute pancreatitis (AP). This study aimed to determine subsets related to development of AP in patients with severe HTG and the severity of HTG-induced AP (HTG-AP).MethodsPatients who had severe HTG (serum triglyceride level >1,000 mg/dL) more than once between Jan. 2010 and Dec. 2017 in a single institute were evaluated retrospectively. Patients were divided into two groups, with AP or without AP, and were compared. HTG-APs in patients with severe HTG were compared to APs due to other causes during the same period.ResultsSixty-three patients (19.3%) presented with AP of a total 326 patients with severe HTG. The AP group displayed younger age, more alcohol consumption and diabetes mellitus, and higher initial/maximum serum levels of triglyceride, glucose, HbA1c, total cholesterol, and calculated non-high-density lipoprotein cholesterol (p < 0.05). HTG-APs were clinically more severe compared with 277 APs due to other causes in terms of CRP (p < 0.001), CT severity index (p = 0.002), revised Atlanta classification (p < 0.001), and hospital stay (p = 0.011). In logistic regression analysis, maximum serum triglyceride level (OR 2.706, p = 0.015), alcohol consumption amount (OR 5.292, p < 0.001), and age (OR 0.358, p = 0.017) were independently associated with development of AP in patients with severe HTG.ConclusionsDevelopment of AP in patient with severe HTG was independently associated with younger age, higher serum TG level, and more alcohol consumption. HTG-APs are clinically more severe than APs due to other causes.     

Heat shock proteins and autophagy in rats with cerulein-induced acute pancreatitis

Background/Aims

Heat shock proteins (HSPs) protect rats from cerulein-induced acute pancreatitis (AP) by preventing the subcellular redistribution of cathepsin B and the activation of trypsinogen. Autophagy plays a critical role in the secretion of digestive enzymes and triggering of cerulein-induced AP via the colocalization of trypsinogen and lysosomes. Therefore, using a rat cerulein-induced AP model, we investigated whether HSPs prevent AP by regulating autophagy.

Methods

Twelve hours after fed standard laboratory chow and water, the experimental groups (cerulein, water-immersion [WI]-cerulein and heat-shock [HS]-cerulein) and the control groups (control, WI, and HS) received one intraperitoneal injection of cerulein (50 µg/kg) or saline, respectively. All of the rats were sacrificed at 6 hours after injection. The severity of the AP was assessed based on the serum amylase level and the histological and electron microscopy findings. Western blotting was also performed for HSP60/70 and LC3B-II.

Results

WI and HS induced HSP60 and HSP70, respectively. The induced HSP60/70 effectively prevented the development of cerulein-induced AP. Autophagy developed in the rats with cerulein-induced AP and was documented by the expression of LC3-II and electron microscopy findings. The WI-stressed rats and HS-treated rats did not develop cerulein-induced autophagy.

Conclusions

HSPs exert protective effects against cerulein-induced AP in rats by inhibiting autophagy.     

Factors associated with the severity of hypertriglyceridemia induced acute pancreatitis

Hypertriglyceridemia induced acute pancreatitis (HTGP) was associated with increased risk of local complications, recurrent acute pancreatitis (AP), the frequency of other complications, and its high mortality as compared to other causes. Determining the factors associated with the severity of HTGP was necessary and important in the management of patients with AP.This study aims to examine the clinical and biochemical characteristics of HTGP patients, and to determine the factors associated with the severity of HTGP according to the revised Atlanta classification.This retrospective and prospective study enrolled 157 HTGP patients from January 2016 to May 2019 at Cho Ray Hospital who had serum TG levels measured within the first 48 hours of admittance with a TG concentration ≥ 1000 mg/dL and excluded other causes. The clinical features and outcomes of patients with HTGP were determined in terms of demographics, clinical symptoms, laboratory data, system complications, local complications, disease severity, and length of hospital stay. The primary outcome was the severity of HTGP as based according to the revised Atlanta classification. We evaluated the relationship between general information, clinical factors and laboratory data in the study population.There were 157 HTGP patients participated in this study. Patients with HTGP had evidence of obese or overweight range (61.2%), history of diabetes mellitus (32.5%) or undiagnosed diabetes (28.0%), history of AP (35.7%), alcohol use (23.6%), hypertension (15.9%), dyslipidemia (13.4%). The patients had typical symptoms of AP, including pancreatic abdominal pain (upper abdominal pain) (93%), nausea/vomiting (80.9%), fever (59.2%), distension abdomen (84.7%), and resistance of abdominal wall (24.8%). The severity of HTGP was significantly associated with fever, altered mental status, rapid pulse, and hypotension (P < .05). Patients with severe HTGP had significantly more pancreatic necrosis, higher values of Blood urea nitrogen and creatinine, longer prothrombin time and activated partial thromboplastin time on admission and higher CRP₄₈ than not severe HTGP (P < .05).The severity of HTGP was significantly related to clinical factors including fever, altered mental status, rapid pulse, hypotension, and pancreatic necrosis. The value of Blood urea nitrogen, creatinine, prothrombin time, and activated partial thromboplastin time at admission is higher and longer in the severe AP group with P < .05.     

Adiponectin deficiency enhanced the severity of cerulein-induced chronic pancreatitis in mice

Background

Adiponectin is recognized as an antiinflammatory and antifibrotic protein derived from adipocytes, and low serum adiponectin levels are present in obesity. Recent studies have highlighted the relationship between obesity and pancreatic diseases. However, the role of adiponectin in chronic pancreatitis remains uncertain. The aim of this study was to determine the effects of adiponectin in chronic pancreatitis.

Methods

We investigated the effects of adiponectin in experimental chronic pancreatitis by using adiponectin-knockout (APN-KO) mice. Chronic pancreatitis was induced by repeated hourly (6 times) intraperitoneal injections of 50 µg/kg cerulein three times per week for 4 weeks in wild-type (WT) and APN-KO mice. We evaluated the severity of chronic pancreatitis biochemically and morphologically.

Results

In cerulein-treated mice, macroscopically and histologically, severe pancreatic damage was observed in APN-KO mice compared with findings in WT mice. The histological scores for chronic pancreatitis, including glandular atrophy, pseudotubular complex, fibrosis, and total scores, were significantly higher in APN-KO mice than in WT mice. Activated pancreatic stellate cells and F4/80-positive pancreatic macrophages accumulated in the pancreas of APN-KO mice but not in WT mice. Overexpression of the mRNAs of transforming growth factor-β1, CD68, and monocyte chemoattractant protein-1 was noted in APN-KO mice but not in WT mice. The gene expression level of collagen1 (α1) tended to be higher in APN-KO mice than in WT mice, albeit insignificantly.

Conclusions

Adiponectin deficiency enhanced the severity of cerulein-induced chronic pancreatitis in mice. Hypoadiponectinemia could enhance the severity of chronic pancreatitis.     

Diagnostic evaluation of acute pancreatitis in two patients with hypertriglyceridemia

We present two diagnostically challenging cases of acute pancreatitis with hypertriglyceridemia accompanied with chylomicronemia caused with a deficiency of lipoprotein lipase and with the presence of type V hyperlipidemia. Both cases suffered from acute abdomen following the ingestion of fatty food and revealed the increase in parameters of inflammation without significant elevation of serum amylase levels. The imaging examination of ultrasonography could not detect significant findings of acute pancreatitis and a computer tomography scan eventually confirmed the findings of acute pancreatitis. Both cases responded to a low fat diet and administration of a cholecystokinin receptor antagonist, exhibiting a relief of abdominal symptoms. As in the present cases with acute abdomen following the ingestion of fatty food, the identification of serum hypertriglyceridemia and an abdominal computer tomography scan might be useful in establishing the diagnosis of acute pancreatitis and in developing the therapeutic regimen, when hypertriglyceridemia interferes with the evaluation of pancreatic enzyme activities and ultrasound examination provides poor pancreatic visualization.     

Metachromatic leukodystrophy: natural course of cerebral MRI changes in relation to clinical course

Objective  

Metachromatic Leukodystrophy (MLD) is a rare disorder leading to demyelination and neurological impairment. A natural history study within the German leukodystrophy network analyzed MRI changes with respect to the clinical course.