Pancreatic Weight Research Articles

Protective effect of Hachimi-jio-gan against the development of pancreatic fibrosis and oxidative damage in Otsuka Long-Evans Tokushima Fatty rats

In our previous study, the polyherbal drug Hachimi-jio-gan was reported to possess a protective effect against the progression of diabetic nephropathy by attenuating glucose toxicity and renal damage with a type 2 diabetic model, Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Based on these findings, this study was undertaken to reveal the effect of Hachimi-jio-gan on pancreatic damage focusing on fibrosis and oxidative stress in type 2 diabetes. OLETF rats were orally administered Hachimi-jio-gan for 32 weeks, and we assessed the changes in the serum glucose level every 8 weeks, as well as those of body weight, and food and water consumption every 4 weeks. In addition, pancreatic wet weight, insulin content, and Western blot analyses of transforming growth factor-β 1, fibronectin, and nuclear factor-κB-related inflammatory enzymes, such as inducible nitric oxide synthesis and cyclooxygenase-2, were also performed in the pancreas. As a consequence, long-term treatment with Hachimi-jio-gan had a hypoglycemic effect, reducing pancreatic atrophy and fibrosis, and ameliorating the oxidative status. Therefore, this may provide evidence that Hachimi-jio-gan is a therapeutic target for preventing the development of pancreatic damage concomitant with hyperglycemia in type 2 diabetes.

Ingestion of potato starch decreases chymotrypsin but does not affect trypsin, amylase, or lipase activity in the pancreas in rats

Adaptation of digestive enzymes in the pancreas was evaluated in rats fed diets composed of potato starch as a carbohydrate source. Male Sprague-Dawley rats at 7 weeks were fed 4 different diets containing 60% sucrose, cornstarch, or 2 kinds of starch derived from different potato varieties. Enzyme activity in the pancreas of rats was determined at 0, 1, 3, and 5 weeks. Although amylase activity slightly increased with increasing pancreatic weights in all diet groups, there were no differences in amylase activity among diet groups throughout the experimental period. Although lipase activity increased abruptly from 1 to 3 weeks of feeding in all diet groups, there were no differences in lipase activity among the 4 diet groups throughout the feeding period. Trypsin activity was not affected by the type of diet or feeding period from 1 to 5 weeks. Chymotrypsin activities in rats fed the 2 potato starch diets were lower than those in rats fed the sucrose or cornstarch diet at 1, 3, and 5 weeks. These results indicate that ingestion of potato starch suppresses only chymotrypsin activity in the pancreas of rats. Although the mechanism is not clear at present, protease inhibitor in potato starch is probably involved in suppressing chymotrypsin activity in the rat pancreas in vivo.

Pioglitazone attenuates the severity of sodium taurocholate-induced severe acute pancreatitis

To determine the effect of pioglitazone, a specific peroxisome proliferator-activated receptor-gamma (PPARgamma) ligand, on development of severe acute pancreatitis (SAP) and expression of nuclear factor-kappa B (NF-kappaB) and intercellular adhesion molecule-1 (ICAM-1) in the pancreas. Male Sprague-Dawley (SD) rats (160-200 g) were randomly allocated into three groups (n = 18 in each group): severe acute pancreatitis group, pioglitazone group, sham group. SAP was induced by retrograde infusion of 1 mL/kg body weight 5% sodium taurocholate (STC) into the biliopancreatic duct of male SD rats. Pioglitazone was injected intraperitoneally two hours piror to STC infusion. Blood and ascites were obtained for detecting amylase and ascitic capacity. Pancreatic wet/dry weight ratio, expression of NF-kappaB and ICAM-1 in pancreatic tissues were detected by immunohistochemical staining. Pancreatic tissue samples were stained with hematoxylin and eosin (HE) for routine optic microscopy. Sham group displayed normal pancreatic structure. SAP group showed diffuse hemorrhage, necrosis and severe edema in focal areas of pancreas. There was obvious adipo-saponification in abdominal cavity. Characteristics such as pancreatic hemorrhage, necrosis, severe edema and adipo-saponification were found in pioglitazone group, but the levels of those injuries were lower in pioglitazone group than those in SAP group. The wet/dry pancreatic weight ratio, ascetic capacity, serum and ascitic activities of anylase in the SAP group were significantly higher than those in the sham group and pioglitazone group respectively (6969.50 +/- 1368.99 vs 2104.67 +/- 377.16, 3.99 +/- 1.22 vs 2.48 +/- 0.74, P < 0.01 or P < 0.05). According to Kusske criteria, the pancreatic histologic score showed that interstitial edema, inflammatory infiltration, parenchyma necrosis and parenchyma hommorrhage in SAP group significantly differed from those in the sham group and pioglitazone group (7.17 +/- 1.83 vs 0.50 +/- 0.55, 7.67 +/- 0.82 vs 6.83 +/- 0.75, P < 0.01, P < 0.05. The expression of NF-kappaB and ICAM-1 in sham group was lower than that in SAP group and pioglitazone group (0.50 +/- 0.55 vs 33 +/- 1.21, P < 0.01). There was a significant difference in the expression of NF-kappaB and ICAM-1 between SAP group and pioglitazone group (7.50 +/- 1.05 vs 11.33 +/- 1.75, 0.80 +/- 0.53 vs 1.36 +/- 0.54, P < 0.01 or P < 0.05) at 12 h after the induction of pancreatitis. Pioglitazone attenuates the severity of SAP. The beneficial effect of pioglitazone is multifactorial due to its anti-inflammatory activities, most likely through the inhibition of ICAM-1 expression and NF-kappaB activation. Specific ligands of PPARgamma may represent the novel and effective means of clinical therapy for SAP.

EUS–guided pancreaticogastrostomy: analysis of its efficacy to drain inaccessible pancreatic ducts

EUS-guided pancreaticogastrostomy (EPG) has been reported as an alternative to surgery in cases of pancreatic stricture where ERCP is unsuccessful. We analyzed our 3-year experience with this innovative technique. Patients with failed ERCP for pancreatic drainage were offered EPG over a 3-year period and were followed up prospectively in terms of clinical and radiologic response. Tertiary care center offering ERCP and interventional EUS. Thirteen patients were included in this study. Seven had surgical diversion Six patients had unaltered enteral anatomy and stricture related to chronic pancreatitis (3), gallstone pancreatitis (2), and intraductal pancreatic mucinous neoplasm (1). EUS-guided puncture and opacification of the pancreatic duct was performed, creating a transgastric fistula with placement of a guidewire into the main pancreatic duct and subsequent ductal decompression with a plastic endoprosthesis. Mean main pancreatic duct size, pain score, and weight before and after intervention. Ten patients had successful endoprosthesis placement across the pancreaticogastric fistula. One patient underwent brush cytologic study, which diagnosed pancreatic malignancy, and underwent surgical resection. After a mean follow-up of 14 months, the mean pancreatic duct size in treated patients decreased from 4.6 to 3.0 mm (P = .01); the pain score decreased from 7.3 to 3.6 (P = .01). Complications included one case of bleeding requiring hemoclip placement and 1 case of contained perforation. Pilot study from a single center. EPG is a safe and feasible alternative to surgical intervention in this subgroup of patients where conventional ERCP is not possible.

PANCREATIC FIBROSIS INCREASED AFTER DISCONTINUATION OF PRAVASTATIN TREATMENT IN OLETF RAT

Background/Aim: We previously reported that pravastatin treatment exerted beneficial effects on the pancreatic fibrosis in OLETF rats (APA 2004). Although discontinuation or noncompliance of statins seems to be frequent in daily practice, effects of withdrawal of this medicine have been rarely examined to date. In the present study, we sought to clarify whether beneficial effects of pravastatin on pancreatic fibrosis prolong if this treatment is discontinued in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, an animal model of pancreatic fibrosis. Method: Male OLETF rats were randomly divided into 2 groups at 12 weeks of age. First group received a standard rat diet during experimental period (control). The second group received the diet containing 0.05% pravastatin from 12 to 28 weeks and then switched to a standard rat diet until 80 weeks of age (P12-28W). At age 80 weeks, rats were sacrificed and pancreas was taken. Results: Pancreatic wet weight, DNA content and superoxide dismutase (SOD) activity significantly decreased in the P12-28W compared with those in the control. Pancreatic protein content was lower in the P12-28W than that in the control, and expression level of transforming growth factor-beta 1 mRNA in the pancreas was higher in the P12-28W than that in the control, but statistical significant difference was not obtained. Histological examination revealed that the pancreas was atrophic, and inter- and intraloblar fibrosis were markedly observed in the P12-28W and control. Quantitative evaluation of the rate of fibrosis area using an interactive image analysis system revealed that fibrotic area was significantly increased in the P12-28W compared with that in the control. Conclusion: Present results suggest that discontinuation of pravastatin treatment increased pancreatic fibrosis probably by decreasing SOD activity. Since discontinuation of pravastatin completely abrogated its beneficial effect, discontinuation of this treatment should be avoided.

THE ROLE OF PANCREATIC PHOSPHOLIPASE A2 IN EXPERIMENTAL PANCREATITIS

Premature intracellular activation of digestive zymogens is regarded as an initial and initiating event for acute pancreatitis. While the activation of proteolytic zymogens was shown in numerous studies, the role of other digestive enzymes is much less clear. Several authors have suggested that Phosholipase A2 is responsible for proteolytic injury of pancreatic acini. However, earlier studies have never investigated the role of the ancreatic secretory phospholipase A2 (PLA2, type 1b) in contrast to the well known and studied leukocyte PLA2, (PLA2, type 2a). Pancreatic secretory-PLA2-deficient mice were generated by targeted disruption of the PLA2 gene (Gastroenterology 2001; 120:1193-1202). Acute pancreatitis was induced by 7 hourly injections of caerulein (50μg/h, i.p.). Control mice received i.p. saline. Activities of amylase, lipase, myeloperoxidase, trypsin and PLA2 were enzymatically measured with specific substrates. Histological evaluation of pancreatic injury was performed after H&E staining, and apoptosis was analysed by 3-OH nick-end labelling. Pancreatic edema was calculated as ratio of pancreatic wet weight to body mass. CCK-induced necrosis in isolated acinar cells was measured by propidium iodide inclusion. PLA2 expression and PLA2 activity was absent in PLA2-KO animals. In wild type animals we detected a high PLA2 basal activity with a 3-fold increase after supramaximal caerulein stimulation. As an endogenous activator of PLA2 we identified Cathepsin L. Supramaximal caerulein stimulation induced early pancreatic injury as indicated by high levels of serum amylase and lipase in wild-type mice but there was no significant difference in comparison to knock-out animals. The pancreatic inflammatory reaction indicated by myeloperoxidase levels and CD45 staining was reduced; in parallel we detected a 7 fold increase in the rate of apoptosis in PLA2 KO animals. Isolated acinar cells from both animal groups showed no difference in CCK-induced necrosis or trypsin activity. Our data clearly indicate that activation of the secretory pancreatic pro-PLA2 plays a role in mediating the systemic inflammatory response, but has little or no impact on the initiation or propagation of the digestive enzyme activation cascade in pancreatic acini eventually leading to cell necrosis. The deletion of PLA2 leads to a shift of cell death from predominantly necrosis to apoptosis.

Establishment of Animal Models for Three Types of Pancreatitis and Analyses of Regeneration Mechanisms

To investigate the mechanisms underlying the onset and progress of pancreatitis, 3 animal models (chronic, acute, and severe pancreatitis) were established by double ligature of the pancreatic duct, injection with cerulein, or injection with cerulein + double ligature of the pancreatic duct. We prepared a control and 3 experimental groups: group 1 (untreated control), group 2 (a chronic pancreatitis model; the pancreatic tail was exposed through a midline incision, and the pancreatic duct from this part was double-ligated), group 3 (an acute pancreatitis model; cerulein was intraperitoneally injected 7 times on day 0), and group 4 (a severe pancreatitis model; the double ligature of the pancreatic duct plus injection of cerulein). Kinetic observations of survival rate, relative pancreatic weight, and the macroscopical and microscopical diagnoses and observations of the changes in endocrine function clearly show that these 3 murine models of pancreatitis can serve as human models for chronic, acute, and severe pancreatitis. Furthermore, pancreas duodenum homeobox 1, cytokeratin 19, and Ki67 are expressed at the site of injury in the pancreas, resulting from the injection with cerulein and/or double ligature of the pancreatic ducts and indicating that there remains a tissue-regenerative capacity. These 3 mouse models could serve as human models for chronic, acute, and severe pancreatitis. Furthermore, cells of the epithelial lineage might participate in tissue regeneration in chronic, acute, and severe pancreatitis.

Soya-bean agglutinin induced both direct and cholecystokinin-mediated pancreatic enzyme synthesis in rats

AbstractThis study was conducted to examine the relationship between soya-bean agglutinin and cholecystokinin in stimulating pancreatic enzyme synthesis in rats. In experiment 1, 30 rats were given daily gastric infusions of 0, 3·5, 7·0, 10·5, or 14·0 mg of soya-bean agglutinin (no.=6) for 14 days. Compared with the control group, soya-bean agglutinin reduced weight gains, enhanced absolute and relative dry pancreatic weights, elevated serum cholecystokinin levels, and stimulated cholecystokinin mRNA expression in the intestine (P&lt;0·001). Pancreatic nucleic acid composition and the pancreatic activities of the enzymes amylase, trypsin and chymotrypsin all increased in response to increasing levels of soya-bean agglutinin (P&lt;0·001). In experiment 2, duodenal cells obtained from two rats were incubated at 37°C with either saline, 100 μg/ml soya-bean agglutinin, or a mixture of 100 μg/ml soya-bean agglutinin and 10 mmol/m of the L-type, calcium channel antagonist verapamil. Soya-bean agglutinin stimulated cholecystokinin mRNA expression and cholecystokinin release from small intestinal mucosal cells, and the effect was attenuated by verapamil. In experiment 3, pancreatic acinar cells, obtained from three rats, were incubated at 37 °C with either saline, or cholecystokinin (100 fmol/ml) and soya-bean agglutinin (1000 fmol/ml), either alone or in combination. Amylase, trypsin, and chymotrypsin activities from both culture media and acini cells were stimulated by both the soya-bean agglutinin and the cholecystokinin treatments. Enzyme activities, when the two factors were incubated in combination, were intermediate to those obtained when the factors were incubated alone. This suggesting that soya-bean agglutinin may depress the action of cholecystokinin on pancreatic enzymatic activities. In summary, soya-bean agglutinin appears to stimulate pancreatic enzyme synthesis both directly and also through a cholecystokinin-mediated pathway.

Effects of Chinese herbal medicines on spontaneous chronic pancreatitis in rats and the pathological relationships between formulas and syndromes

To investigate the effects of Guizhi Decoction, Chaihu Guizhi Decoction, Xiaochaihu Decoction and camostat on rat spontaneous chronic pancreatitis and the pathological relationships between formulas and syndromes. Fifty-seven male WBN/Kob rats at age of 4 weeks were divided into five groups: untreated group (n=18), Guizhi Decoction-treated group (n=9), Chaihu Guizhi Decoction-treated group (n=9), Xiaochaihu Decoction-treated group (n=9) and camostat-treated group (n=12). The rats in each group were fed with corresponding drugs for 12 weeks. The pancreatic wet weight and histopathological changes of pancreatic tissue were observed every four weeks. Meanwhile, the expression level of pancreatitis-associated protein (PAP) in pancreas was detected by RT-PCR technique and immunohistochemical method. In the untreated group, the histopathological changes in pancreas were observed in rats at 12-week age, while such changes were absent in the Guizhi Decoction-treated group. The histopathological changes in pancreas were quite remarkable in rats at 16-week age in both the Xiaochaihu Decoction-treated and the camostat-treated groups. The expression level of PAP mRNA was lower in the Guizhi Decoction-treated group than those in the other groups. The PAP expressions were absent in rats at 12-week age in the Guizhi Decoction-treated and the Chaihu Guizhi Decocion-treated groups. Guizhi Decoction, Chaihu Guizhi Decoction, Xiaochaihu Decoction and camostat are all beneficial to prevention and cure of chronic pancreatitis, and Guizhi Decoction is the most effective one. It is speculated that Taiyang exterior syndrome may be the pathogenesis of basic syndrome may be the pathogenesis of basic syndrome of spontaneous chronic pancreatitis, and the expression of PAP may be its pathological basis.

Tolfenamic Acid and Pancreatic Cancer Growth, Angiogenesis, and Sp Protein Degradation

Sp1, Sp3, and Sp4 are transcription factors that regulate cell proliferation and vascular endothelial growth factor (VEGF) expression and are overexpressed in many cancer cell lines. For some cancers, Sp1 overexpression is associated with poor survival. Cyclooxygenase inhibitors decrease Sp1 expression in cancer cells, and therefore different structural classes of nonsteroidal anti-inflammatory drugs (NSAIDs) were screened for their ability to decrease levels of Sp1, Sp3, and Sp4 and to decrease pancreatic tumor growth and metastasis in an in vivo model. Levels of Sp1, Sp3, Sp4, and VEGF proteins in pancreatic cancer cell lines were assessed by immunoblot analysis. mRNA was assessed by reverse transcription-polymerase chain reaction. Panc-1 pancreatic cancer cells transfected with VEGF promoter constructs were used to assess VEGF promoter activation. Pancreatic tumor weight and size and liver metastasis were assessed in an orthotopic mouse model of pancreatic cancer (groups of 10 mice). Protein expression in tumors was assessed immunohistochemically. Tolfenamic acid and structurally related biaryl derivatives induced degradation of Sp1, Sp3, and Sp4 in pancreatic cancer cells. Tolfenamic acid also inhibited VEGF mRNA and protein expression in pancreatic cancer cells; this inhibition was associated with the decreased Sp-dependent activation of the VEGF promoter. In the mouse model for pancreatic cancer, treatment with tolfenamic acid (50 mg/kg of body weight), compared with control treatment, statistically significantly decreased tumor growth and weight (P = .005), liver metastasis (P = .027), and levels of Sp3 and VEGF (P = .009) and Sp1 and Sp4 (P = .006) proteins in tumors. For example, tumors from mice treated with tolfenamic acid (50 mg/kg) had statistically significantly lower VEGF levels (45%, 95% confidence interval = 39% to 51%; P = .009) than tumors from control mice. Tolfenamic acid is a new antipancreatic cancer NSAID that activates degradation of transcription factors Sp1, Sp3, and Sp4; reduces VEGF expression; and decreases tumor growth and metastasis.

Effects of soybean agglutinin on body composition and organ weights in rats

An experiment was conducted to assess the effect of soybean agglutinin dosage level on growth, body composition, plasma lipids, glucose, urea nitrogen content and aminotransferase activities in rats. Male and female rats (n = 60) weaned at 19 d were given a dose of 0, 3.5, 7.0, 10.5, or 14.0 mg soybean agglutinin by gastric infusion once daily for 10 days. With increasing doses of soybean agglutinin, body weight, lipid content of carcass, spleen and kidneys relative dry weights decreased, while small intestine and pancreatic weight, the contents of urea nitrogen and triglyceride, and the activities of aspartate aminotransferase linearly increased in plasma. Though soybean agglutinin decreased plasma insulin content, changes in plasma glucose content due to soybean agglutinin were not detected. It is suggested that dietary soybean agglutinin may affect the secretion of other hormones besides insulin, which modulate blood glucose reserves. In conclusion, consumption of soybean agglutinin resulted in a depletion of lipid and an overgrowth of small intestine and pancreas in rats. Meanwhile, poor growth of spleen and kidneys was observed in the soybean agglutinin-fed rats.

Effect of inhibition of α-glucosidase on age-related glucose intolerance and pancreatic atrophy in rats

Oral administration of α-glucosidase inhibitor reduces postprandial serum glucose and insulin concentrations; thus, α-glucosidase inhibitor is used for the treatment of diabetes mellitus worldwide. In our study, we have evaluated the effect of α-glucosidase inhibitor, acarbose, on age-related glucose intolerance and pancreatic atrophy in the Long-Evans Tokushima Otsuka (LETO) rat. The first group of rats received a standard rat diet (control). The second group received a diet containing acarbose (150 mg/100 g food) from 12 to 28 weeks and then switched to a standard rat diet until 72 weeks of age (A12-28W). The third group was administered the same diet containing acarbose from 12 to 72 weeks of age (A12-72W). Fasting serum glucose and insulin concentrations gradually increased with increasing age in the control group, but these increases were completely prevented (A12-72W) or delayed (A12-28W) by acarbose treatment. In addition, acarbose treatment prevented the deterioration in insulin resistance with increasing age. At 72 weeks of age, pancreatic wet weight and DNA content in the A12-72W group were significantly higher than those in the control group. Although most islets were enlarged, and some portions of pancreatic tissue contained fatty and connective tissue in the control group, these alterations were mild in the A12-28W group and remained minimal in the A12-72W group. Our study suggests that acarbose is useful in the prevention of age-related glucose intolerance and pancreatic atrophy.

Impaired growth of pancreatic exocrine cells in transgenic mice expressing human activin βE subunit

Activins, TGF-β superfamily members, have multiple functions in a variety of cells and tissues. Recently, additional activin β subunit genes, βC and βE, have been identified. To explore the role of activin E, we created transgenic mice overexpressing human activin βE subunit. There were pronounced differences in the pancreata of the transgenic animals as compared with their wild-type counterparts. Pancreatic weight, expressed relative to total body weight, was significantly reduced. Histologically, adipose replacement of acini in the exocrine pancreas was observed. There was a significant decrease in the number of PCNA-positive cells in the acinar cells, indicating reduced proliferation in the exocrine pancreas of the transgenic mice. However, quantitative pancreatic morphometry showed that the total number and mass of the islets of the transgenic mice were comparable with those of the nontransgenic control mice. Our findings suggest a role for activin E in regulating the proliferation of pancreatic exocrine cells.

IV Hypertonic Glucose Stimulates the Exocrine Pancreas in Rat

Pancreatic atrophy and dysfunction resulting from parenteral nutrition (PN) may be explained by several mechanisms; one of the important factors is the nutrient in the circulation, which affects the pancreatic growth and secretion. The effect of nutrients on the pancreatic exocrine still has controversies. The aim of the present study is to better understand the effect of i.v. glucose on the exocrine pancreas stimulated by cholecystokinin during the parenterally fed condition. Two mixed solutions consisting of 30% and 50% glucose, respectively, were used. Thirty male Sprague-Dawley rats were randomly divided into 5 groups, including a control group; a freely fed group received cholecystokinin; 2 groups were infused with 30% and 50% glucose, and a group was infused with 50% glucose with cholecystokinin. The body weight and pancreatic contents were measured after 10 days. The body weight in all groups was increased but lower than in the freely fed rats. I.v. glucose caused a decrease in the pancreatic weight, the amount of the pancreatic protein and DNA, and the level of amylase but elevated the level of trypsin in all treated groups. The enzymes were elevated after infusion of cholecystokinin with glucose, but they were lower than in freely fed animals with cholecystokinin. Compared with 30% glucose, 50% glucose elevated the level of amylase but did not affect the level of trypsin. I.v. glucose results in atrophy of the exocrine pancreas, elevates the amylase in pancreas, but suppresses the stimulatory effect of cholecystokinin on the exocrine pancreas.

Dexamethasone mediates protection against acute pancreatitis via upregulation of pancreatitis-associated proteins.

To examine the influence of dexamethasone on pancreatitis-associated protein (PAP) gene expression using both in vitro and in vivo models of acute pancreatitis and to study how PAP gene expression correlates with severity of pancreatitis. In vitro, IL-6 stimulated pancreas acinar AR42J cells were cultured with increasing concentrations of dexamethasone and assayed for PAP expression (RT-PCR). In vivo, pancreatitis was induced in rats by retrograde injection of 40 g/L taurocholate into the pancreatic duct. Animals were pretreated with dexamethasone (2 mg/kg) daily or saline for 4 d. Pancreata and serum were harvested after 24 h and gene expression levels of PAP I, II and III were measured by RT-PCR. Severity of pancreatitis was based on serum amylase, pancreatic wet weight, and histopathological score. In vitro, dexamethasone and IL-6 induced a marked transcription of PAP I, II and III genes in AR42J cells at 24 h (P < 0.05 for all comparisons). In vivo, pancreas mRNA levels of PAP I, II or III increased by 2.6-fold, 1.9-fold, and 1.3-fold respectively after dexamethasone treatment, compared with saline treated animals. Serum amylase levels and edema were significantly lower in the dexamethasone group compared with the saline group. Histopathologic evaluation revealed less inflammation and necrosis in pancreata obtained from dexamethasone treated animals (P < 0.05). Dexamethasone significantly decreases the severity of pancreatitis. The protective mechanism of dexamethasone may be via upregulating PAP gene expression during injury.

Morphometric and immunohistochemical patterns of duodenal CCK-cells in rats with portacaval shunts

End-to-side portacaval shunt (PCS) performed in rats is an appropriate experimental model of chronic liver insufficiency. Functional hepatic injury followed by numerous metabolic and endocrine disorders develops, as well. Due to impaired functional hepatic activity in PCS and to the well known role of the liver in CCK metabolism and elimination, delayed CCK bloodstream elimination may be responsible for increased CCK-A receptor activity. Therefore, we investigated immunohistochemical and morphometric features of duodenal CCK-cells in rats with PCS. Male Wistar rats (180 - 250g body weight) were used in this experiment. The animals were divided into two groups: PCS-animals (experimental group (n=27) which underwent an operation) and C - unoperated animals [control group (n=11)]. End-to-side portacaval anastomosis was created using the technique of Lee and Fisher, modified by Bismuth et al. Eight weeks, after the operation, animals were sacrificed. Pancreatic and hepatic weights were measured and samples taken from appropriate segments of the small intestine were used for morphometric and immunohistochemical CCK-cells determination. IMMUNOHISTOCHEMICAL TECHNIQUE: Peroxidase-antiperoxidase (PAP) technique described by Stenberger was applied for detection of intestinal CCK-immunoreactive cells. Our results indicate that eight weeks after operation liver weight was reduced in animals with PCS compared to control animals (p<0.01). To the contrary, in comparasion with control animals, the pancreatic wight was increased (p<0.01). In the exocrine pancreas of rats with PCS there were lipid droplets and hypertrophy of the acinus cells. The morphometric analysis of CCK-immunoreactive cells in different small intestine segments indicates that in the duodenum of animals with PCS there was a significant cell increase compared to control, unoperated animals. In liver cirrhosis, plasma CCK-8 concentration increases. In PCS, performed in rats, as an experimental model of chronic liver insufficiency, proliferation of CCK-cells in the small intestine leads to pancreatic hypertrophy and hyperplasia.

Duodenogastric reflux enhances growth and carcinogenesis in the rat pancreas.

Surgery for peptic ulcer disease may increase the risk of pancreatic cancer. The effect of duodenogastric reflux on pancreatic carcinogenesis was tested, and changes in the circulating levels of cholecystokinin (CCK) and gastrin were measured. Male Wistar rats (n = 40) weighing 250-300 g were randomized to undergo gastrotomy (control) or split gastrojejunostomy (to produce complete duodenogastric reflux) and then to receive azaserine (30 mg/kg/week intraperitoneally) or saline injections for 3 weeks. At 6 months, blood CCK was assayed and the pancreas was excised for quantitative estimation of atypical acinar cell foci (AACF), the precursor lesions of carcinoma. Rats that had undergone split gastrojejunostomy weighed 15-19 per cent less than controls (P < 0.05), but their relative pancreatic weight (mg pancreas per 100 g body-weight) was 52-60 per cent greater (P < 0.001). Acidophilic AACF occurred only in azaserine-treated rats with duodenogastric reflux. Although plasma CCK concentrations were unchanged, split gastrojejunostomy increased basal and postprandial gastrin levels by 98-175 per cent (P < 0.05). Duodenogastric reflux produces sustained hypergastrinaemia and promotes experimental pancreatic carcinogenesis.

Tropic role of enteroglucagon in pancreatic adaptation to subtotal enterectomy

Proximal small bowel resection causes pancreatic hyperplasia, presumably via a humoral mechanism. Although cholecystokinin can stimulate pancreatic growth, its proximal distribution in the gut makes it an unlikely intermediary after proximal small bowel resection. The potential roles of neurotensin and enteroglucagon were studied, since these hormones are mainly secreted from the ileum and proximal colon. Male Wistar rats (n = 50) weighing 200-250 g were randomized to receive 90 per cent proximal small bowel resection or jejunal transection and resuture (control). Rats were killed at 1 week or 1 month, when plasma was obtained for hormone assay and the pancreas was excised for protein and nucleic acid measurement. Proximal small bowel resection increased circulating enteroglucagon levels by 150 per cent at 1 week (P less than 0.002) and by 83 per cent at 1 month (P less than 0.005); neurotensin levels were unchanged. Pancreatic wet weight was 21 per cent greater 1 month after proximal small bowel resection (P less than 0.001). Proximal small bowel resection increased protein, RNA and DNA contents of the pancreas both at 1 week and at 1 month. Since plasma enteroglucagon correlated with these indices of pancreatic mass, enteroglucagon may have a pancreatotropic role (in addition to its enterotropic role).

Efeitos de fontes protéicas na dieta sobre a morfologia intestinal e o desenvolvimento pancreático de leitões recém-desmamados

Objetivou-se neste trabalho analisar os efeitos do uso de hidrolisado protéico do conteúdo celular de levedura (HPCCL), da proteína isolada de soja (PIS), do hidrolisado protéico de mucosa intestinal de suínos (HPMIS) e do leite em pó integral em substituição parcial ao farelo de soja sobre a morfologia do intestino delgado e o desenvolvimento pancreático de leitões aos 7 e 14 dias pós-desmame. Foram utilizados 44 leitões desmamados aos 21 dias de idade, com peso de 5,5 ± 0,6 kg, alimentados desde o desmame com as seguintes dietas isonutritivas: FS - ração à base de milho e farelo de soja; LPI - ração FS + leite em pó integral; LPI+HPMIS - ração LPI mais HPMIS; LPI+PIS - ração LPI mais PIS; LPI+HPCCL- ração LPI mais HPCCL. Os tratamentos não influenciaram a morfologia intestinal dos leitões, evidenciando que nenhuma das fontes protéicas utilizadas foi capaz de minimizar os efeitos deletérios da mudança da alimentação sobre a vilosidade intestinal. Os animais alimentados com LPI+PIS e LPI+HPMIS apresentaram, aos sete dias pós-desmame, o maior desenvolvimento pancreático. Concluiu-se, portanto, que todas as fontes protéicas estudadas foram igualmente adequadas para a formulação de dietas de desmame.

IN VIVO MOLECULAR EVIDENCE ON CHEMOSENSITIZATION OF PANCREATIC TUMOR BY GENISTEIN

Purpose: In our previous communications, we reported the efficacy of genistein in augmenting the effects chemotherapeutic agents such as cisplatin and gemcitabine in pancreatic cancer cells in vitro (S.Banerjee et.al., APA-2004; AACR-2005). Here we report mechanism based evidence for the observed beneficial effect in vivo in SCID mice bearing orthotopically implanted pancreatic cancer cells. Method: Female nude mice (ICR-SCIDS) orthotopically implanted with COLO-357 and L3.6pl tumor cells were randomized into treatment groups comprising (n = 7): (a) Untreated control; (b) Only cisplatin or gemcitabine treatment; (c) Genistein treated (1 mg/mouse/day orally by gavage); and (d) Genistein and cisplatin or gemcitabine following the schedule as for individual treatments. After treatment, tumor samples were analyzed for NF-κB (EMSA) and Western immunoblotting for proapoptotic entities such as, Bcl-xL, and PARP. Results: Analysis of average pancreatic tumor weight in different treatment groups revealed that treatment with genistein and cisplatin/or gemcitabine resulted in a significant reduction in tumor weight relative to tumor weight in control animals. Furthermore, corollary to our previous in vitro findings, we confirmed in our in vivo animal model the potential of genistein to abrogate cisplatin/gemcitabine induced NF-κB activation (which contributes in attenuating chemotherapeutic - drug induced chemo-resistance) resulting in sensitizing tumor cells to undergo apoptotic cell death. Elucidation of downstream targets of NF-κB such as anti-apoptotic BcL-xL was also down regulated alongwith PARP cleavage by genistein treatment thereby augmenting therapeutic efficacy of chemotherapeutic drugs and enhanced apoptosis relative to single agents. Conclusion: Our data provides novel mechanistic insights by which genistein sensitizes in vivo pancreatic tumor cells to chemotherapeutic drugs such as cisplatin and gemcitabine, suggesting that this strategy could be useful clinically in the future.