New chronic pancreatitis model with diabetes induced by cerulein plus stress in rats

Genetically induced vs. classical animal models of chronic pancreatitis: a critical comparison

Chronic pancreatitis (CP) is an utmost complex disease that is pathogenetically linked to pancreas-intrinsic ( e.g., duct obstruction), environmental-toxic ( e.g., alcohol, smoking), and genetic factors. Studying such a complex disease naturally requires validated experimental models. In the past 2 decades, the various animal models of CP usually addressed either the pancreas-intrinsic ( e.g., the caerulein model), the environmental-toxic ( e.g., diet-induced models), or the genetic component of CP. As such, these models were far from mirroring CP in its full spectrum, and the correct choice of models was vital for valid scientific conclusions on CP. The quest for mechanistic, genetic models gave rise to models based on gene modification and transgene insertion, such as the PRSS1 and the IL-1β/IL-1β models. Recently, we witnessed the development of highly exciting models that rely on the importance of autophagy in CP, that is, the murine pancreas-specific Atg5 and LAMP2 knockout models. Today, critical comparison of these several models is more important than ever for guiding research on CP in an efficient direction. The present review outlines the characteristics of the new genetic models in comparison with the well-known classic models for CP, notes the caveats in the choice of models, and also indicates novel directions for model development.-Klauss, S., Schorn, S., Teller, S., Steenfadt, H., Friess, H., Ceyhan, G. O., Demir, I. K. Genetically induced vs. classical animal models of chronic pancreatitis: a critical comparison.

Adipose Stem Cell Therapy Mitigates Chronic Pancreatitis via Differentiation into Acinar-like Cells in Mice

The objective of this study was to assess the capacity of adipose-derived mesenchymal stem cells (ASCs) to mitigate disease progression in an experimental chronic pancreatitis mouse model. Chronic pancreatitis (CP) was induced in C57BL/6 mice by repeated ethanol and cerulein injection, and mice were then infused with 4 × 105 or 1 × 106 GFP+ ASCs. Pancreas morphology, fibrosis, inflammation, and presence of GFP+ ASCs in pancreases were assessed 2 weeks after treatment. We found that ASC infusion attenuated pancreatic damage, preserved pancreas morphology, and reduced pancreatic fibrosis and cell death. GFP+ ASCs migrated to pancreas and differentiated into amylase+ cells. In further confirmation of the plasticity of ASCs, ASCs co-cultured with acinar cells in a Transwell system differentiated into amylase+ cells with increased expression of acinar cell-specific genes including amylase and chymoB1. Furthermore, culture of acinar or pancreatic stellate cell lines in ASC-conditioned medium attenuated ethanol and cerulein-induced pro-inflammatory cytokine production in vitro. Our data show that a single intravenous injection of ASCs ameliorated CP progression, likely by directly differentiating into acinar-like cells and by suppressing inflammation, fibrosis, and pancreatic tissue damage. These results suggest that ASC cell therapy has the potential to be a valuable treatment for patients with pancreatitis.

Animal models of gastrointestinal and liver diseases. Animal models of acute and chronic pancreatitis

Animal models of pancreatitis are useful for elucidating the pathogenesis of pancreatitis and developing and testing novel interventions. In this review, we aim to summarize the most commonly used animal models, overview their pathophysiology, and discuss their strengths and limitations. We will also briefly describe common animal study procedures and refer readers to more detailed protocols in the literature. Although animal models include pigs, dogs, opossums, and other animals, we will mainly focus on rodent models because of their popularity. Autoimmune pancreatitis and genetically engineered animal models will be reviewed elsewhere.

CCR2 knockout exacerbates cerulein-induced chronic pancreatitis with hyperglycemia via decreased GLP-1 receptor expression and insulin secretion

Glucagon-like peptide-1 (GLP-1) promotes insulin release; however, the relationship between the GLP-1 signal and chronic pancreatitis is not well understood. Here we focus on chemokine (C-C motif) ligand 2 (CCL2) and its receptor (CCR2) axis, which regulates various immune cells, including macrophages, to clarify the mechanism of GLP-1-mediated insulin secretion in chronic pancreatitis in mice. One and multiple series of repetitive cerulein administrations were used to induce acute and chronic cerulein pancreatitis, respectively. Acute cerulein-administered CCR2-knockout (KO) mice showed suppressed infiltration of CD11b(+)Gr-1(low) macrophages and pancreatic inflammation and significantly upregulated insulin secretion compared with paired wild-type (WT) mice. However, chronic cerulein-administered CCR2-KO mice showed significantly increased infiltration of CD11b(+)/Gr-1(-) and CD11b(+)/Gr-1(high) cells, but not CD11b(+)/Gr-1(low) cells, in pancreas with severe inflammation and significantly decreased insulin secretion compared with their WT counterparts. Furthermore, although serum GLP-1 levels in chronic cerulein-administered WT and CCR2-KO mice were comparably upregulated after cerulein administrations, GLP-1 receptor levels in pancreases of chronic cerulein-administered CCR2-KO mice were significantly lower than in paired WT mice. Nevertheless, a significantly higher hyperglycemia level in chronic cerulein-administered CCR2-KO mice was markedly restored by treatment with a GLP-1 analog to a level comparable to the paired WT mice. Collectively, the CCR2/CCL2 axis-mediated CD11b(+)-cell migration to the pancreas is critically involved in chronic pancreatitis-mediated hyperglycemia through the modulation of GLP-1 receptor expression and insulin secretion.

Animal models for investigating chronic pancreatitis

Chronic pancreatitis is defined as a continuous or recurrent inflammatory disease of the pancreas characterized by progressive and irreversible morphological changes. It typically causes pain and permanent impairment of pancreatic function. In chronic pancreatitis areas of focal necrosis are followed by perilobular and intralobular fibrosis of the parenchyma, by stone formation in the pancreatic duct, calcifications in the parenchyma as well as the formation of pseudocysts. Late in the course of the disease a progressive loss of endocrine and exocrine function occurs. Despite advances in understanding the pathogenesis no causal treatment for chronic pancreatitis is presently available. Thus, there is a need for well characterized animal models for further investigations that allow translation to the human situation. This review summarizes existing experimental models and distinguishes them according to the type of pathological stimulus used for induction of pancreatitis. There is a special focus on pancreatic duct ligation, repetitive overstimulation with caerulein and chronic alcohol feeding. Secondly, attention is drawn to genetic models that have recently been generated and which mimic features of chronic pancreatitis in man. Each technique will be supplemented with data on the pathophysiological background of the model and their limitations will be discussed.

The complex exocrine-endocrine relationship and secondary diabetes in exocrine pancreatic disorders

The pancreas is a dual organ with exocrine and endocrine functions. The interrelationship of the endocrine-exocrine parts of the pancreas is a complex one, but recent clinical and experimental studies have expanded our knowledge. Many disorders primarily of the exocrine pancreas, often solely in the clinical realm of gastroenterologists are associated with diabetes mellitus (DM). Although, the DM becoming disorders are often grouped with type 2 diabetes, the pathogenesis, clinical manifestations and management differ. We review here data on the association of exocrine-endocrine pancreas, the many hormones of the pancreas and their possible effects on the exocrine functions followed by data on the epidemiology, pathogenesis, and management of DM in chronic pancreatitis, cystic fibrosis, pancreatic cancer, and clinical states after pancreatic surgery.

Interactions between the endocrine and exocrine pancreas and their clinical relevance

In consequence of the close anatomical and functional links between the exocrine and endocrine pancreas, any disease affecting one of these parts will inevitably affect the other. Pancreatic conditions which might cause diabetes mellitus include acute and chronic pancreatitis, pancreatic surgery, cystic fibrosis and pancreatic cancer. The development of diabetes greatly influences the prognosis and quality of life of patients with exocrine pancreatic diseases. It may cause life-threatening complications, such as hypoglycemia, due to the lack of glucagon and the impaired absorption of nutrients, or the micro- and macrovascular complications may impair the organ functions. Diabetes mellitus is an independent risk factor of mortality in those with exocrine pancreatic diseases. The treatment of pancreatic diabetes, a distinct metabolic and clinical form of diabetes, requires special knowledge. Diet and pancreatic enzyme replacement therapy may be sufficient in the early stages. Oral antidiabetic drugs are not recommended. If the diet proves inadequate to reach the glycemic goals, insulin treatment with multiple injections is required. Impairments of the exocrine pancreatic function and morphology in diabetic patients are frequent and well known. Atrophy of the exocrine tissue may be caused by the lack of trophic insulin, whereas pancreatic fibrosis can result from activation of stellate cells by hyperglycemia, or from microangiopathy and neuropathy. The regulation of the exocrine pancreatic function is also damaged because of the impaired effect of islet hormones. In the event of a proven impairment of the pancreatic exocrine function in diabetes mellitus, pancreatic enzyme replacement therapy is indicated. This may improve the nutritional condition of the patient and decrease the metabolic instability.

The current managements of pancreatic diabetes in Japan

Pancreatic diabetes is secondary diabetes followed by progressions of pancreatic exocrine diseases, such as chronic pancreatitis, pancreatic neoplasm and post-pancreatectomy. Because of destruction and reduction of the pancreatic endocrine and exocrine functional compartments, patients with pancreatic diabetes frequently show malnutrition from maldigestion and malabsorption by insufficiencies in pancreatic digestive enzymes, and show unstable glycemic control and prolonged hypoglycemia by insufficiencies in synthesis and secretion of insulin and glucagon. Epidemiological studies have suggested that the incidence and development of pancreatic diabetes in patients with chronic pancreatitis (CP) depends on several risk factors, such as alcohol intake, the presence of pancreatic calcification and the long-term duration of CP. The clinical management of pancreatic diabetes is divided into two parts: one is the supplementation of pancreatic digestive enzymes and the other is the achievement of appropriate glycemic control. The appropriate and sufficient pancreatic exocrine replacement therapy is important for the maintenance of better nutrient conditions for patients with pancreatic diabetes. Furthermore, the intensive insulin therapy combined with short- or ultra-short-acting insulin and long-acting insulin glargine can be achieved for stable glycemic control and reduction of severe frequent hypoglycemia in patients with pancreatic diabetes. These current advanced management techniques against insufficiencies of pancreatic exocrine endocrine functions are beneficial for improving and maintaining the quality of life in patients with pancreatic diabetes.

Pancreatic diabetes in a follow-up survey of chronic pancreatitis in Japan

BACKGROUND

We aimed to determine the cumulative rate of diabetes mellitus (DM) and the risk factors for DM in patients with chronic pancreatitis (CP) in Japan.

METHODS

We conducted a follow-up survey of CP in 2002 in patients registered as having CP in 1994, and confirmed 656 patients to be checked in regard to the survey items concerning diabetes. We analyzed the cumulative rate of DM and the risk factors for DM over an 8-year follow up period.

RESULTS

In 1994, 35.1% of 656 CP patients had DM, and the incidence of diabetes had increased to 50.4% in 2002. Of 418 patients without diabetes in 1994, 28.9% (121/418) were newly diagnosed with DM in 2002. Alcoholic CP was the most common type of CP in patients with newly developed diabetes, accounting for 67.8%. The incidence of DM was highest in those with alcoholic CP (34.3%) followed by idiopathic CP (23.0%). The risk of diabetes increased 1.32-fold after the onset of pancreatic calcification. Of 121 patients with newly diagnosed DM in 2002, 37 (30.6%) had pancreatic stones in 1994 and 49 (40.5%) had a stone in 2002. The highest incidence of newly diagnosed DM was observed in patients with continuous alcoholic intake (40.9%). Patients treated with camostat mesilate developed DM less frequently than those without camostat mesilate.

CONCLUSIONS

The present study showed that the incidence of DM in patients with CP increased with time. Of 418 CP patients without DM in 1994, 28.9% developed DM over a period of 8 years. Continuous alcoholic intake aggravated CP and increased the risk of DM in those with CP.

Hereditary pancreatitis: a model for inflammatory diseases of the pancreas

Acute and chronic pancreatitis remain among the most recalcitrant of all diseases to investigation and intervention. In the majority of patients, excessive alcohol consumption is associated with development of the disease. Therefore, several theories have been proposed seeking to explain the relationship between alcohol and the development of acute and chronic pancreatitis. However, recent investigations in hereditary pancreatitis provided important insights into chronic pancreatitis pathogenesis and offer an important model for understanding pancreatic inflammation. This article highlights several advances gained from investigating hereditary pancreatitis kindreds, and reviews the TIGAR-O risk/aetiology classification system. Finally, the major independent theories on development of chronic pancreatitis are reviewed with respect to the SAPE hypothesis of chronic pancreatitis pathogenesis.

Effect of pancreastatin on cerulein-stimulated pancreatic blood flow and exocrine secretion in anaesthetized rats

BACKGROUND

Pancreastatin (PST) is an inhibitor of pancreatic exocrine secretion in vivo but not in vitro, which suggests that the inhibitory effect of PST is indirect, that is, not mediated by a specific receptor on pancreatic acinar cells. In this study, we investigated the effects of PST on pancreatic exocrine secretion and local pancreatic blood flow in anaesthetized rats to elucidate the participation of PST in indirect regulation of pancreatic exocrine function through blood supply.

METHODS

Pancreastatin (100, 200 or 500 pmol/kg per h) was administered intravenously under background infusion of cerulein (0.5 microg/kg per h), a cholecystokinin analogue. Pancreatic exocrine secretion was monitored by volume and protein output of the pancreatic juice and local pancreatic blood flow was measured by the hydrogen gas clearance method.

RESULTS

Pancreastatin significantly reduced cerulein-induced local pancreatic blood flow in a dose-dependent manner. Pancreatic exocrine secretion was also reduced significantly by PST dose-dependently. Pancreastatin did not change systemic blood pressure. These results suggested that the reduction of pancreatic blood flow is associated with the reduction of pancreatic exocrine secretion.

CONCLUSIONS

We conclude that the mechanism of PST-induced inhibition of pancreatic exocrine secretion is, at least, partly mediated by the reduction of local pancreatic blood flow through blockade, caused by the action of cerulein on pancreatic blood flow.

Morphological study of pancreatic endocrine in an experimental chronic pancreatitis with diabetes induced by stress and cerulein

The purpose of this study was to investigate the morphological changes in the islets observed in a new chronic pancreatitis model with diabetes induced by repetition of cerulein injection plus water-immersion stress in rats. The rats of this model were treated with water-immersion stress for 5 h and two intraperitoneal injections of 20 micrograms/kg body weight of cerulein once a week for 16 weeks. In the stress and cerulein group, 62% of the islets exhibited infiltration of mononucleated cells, and/or peri- and intrainsular fibrosis. On immunohistochemical study, some islets showed reduced density of the insulin immunoreactivity. The glucagon-producing cells decreased in number. With electron microscopy, various endocrine changes were observed, mainly in the B cells. The changes included scattered debris damage with reduction of secretary granules, and vesiculation of the endoplasmic reticulum. Numerous fibroblasts clustered around the islets, and proliferating collagen fibers invaded the islets. The microvascular changes consisted of bleeding and damage to the endothels. In the pancreas treated with stress alone or cerulein alone, significant endocrine damage was not observed. In conclusion, chronic repetitive treatment with stress and cerulein, together with poor islet circulation due to fibrosis and vascular changes, resulted in the endocrine cellular damage.