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

Insulin-like growth factor 1 and insulin-like growth factor binding protein 2 serum levels as potential biomarkers in differential diagnosis between chronic pancreatitis and pancreatic adenocarcinoma in reference to pancreatic diabetes

Introduction

Insulin-like growth factor 1 (IGF-1) has been connected with development of pancreatic ductal adenocarcinoma (PDAC).

Aim

To evaluate the serum concentration levels of IGF-1 and insulin-like growth factor binding protein 2 (IGFBP-2) in patients with chronic pancreatitis (CP) and PDAC. Their values in diabetes mellitus (DM) were also assessed.

Material and methods

The study included 83 patients with CP, 92 patients with PDAC, and 20 subjects as a control group. The concentrations of IGF-1 and IGFBP-2 were estimated with ELISA (Corgenix UK Ltd, R&D Systems).

Results

The IGF-1 was higher in CP compared with PDAC (81.11 ±57.18 ng/ml vs. 53.18 ±36.05 ng/ml, p < 0.001), and both CP and PDAC were different from controls (81.11 ±57.18 ng/ml vs. 70.66 ±16.57 ng/ml, p < 0.001 and 53.18 ±36.05 ng/ml vs. 70.66 ±16.57 ng/ml, p < 0.001). CP without cysts have lower IGF-1 compared to those with CP and cysts (60.35 ±34.68 ng/ml vs. 93.55 ±64.78 ng/ml, p < 0.05). IGF-1 in CP without DM was higher compared to IGF-1 in PDAC without DM (91.13 ±65.48 ng/ml vs. 54.75 ±40.41 ng/ml, p < 0.001). In CP and DM the IGF-1 was elevated in comparison to PDAC and DM (62.20 ±32.38 ng/ml vs. 48.45 ±24.88 ng/ml, p < 0.05). IGFBP-2 was higher in CP compared to PDAC (512.42 ±299.77 ng/ml vs 301.59 ±190.36 ng/ml, p < 0.001). In CP and PDAC the IGFBP-2 level was elevated compared to the control group (512.42 ±299.77 ng/ml vs. 51.92 ±29.40 ng/ml, p < 0.001 and 301.59 ±190.36 ng/ml vs. 51.92 ±29.40 ng/ml, p < 0.001). IGFBP-2 in CP without DM was higher compared to PDAC without DM (559.39 ±281.43 vs. 296.53 ±196.93, p < 0.001).

Conclusions

IGF-1 and IGFBP-2 may be biomarkers of CP and PDAC. IGF-1 may be an indicator that signals whether pancreatic diabetes is from CP or PDAC.

β-Cell dysfunction in chronic pancreatitis

Chronic pancreatitis (CP) is a progressive inflammatory disease characterized by irreversible destruction of pancreatic secretory parenchyma, fibrosis, exocrine atrophy, and endocrine insufficiency leading to diabetes. Secondary diabetes occurring in CP subsequent to destruction of pancreatic β-cells is distinct, since it involves β-cell dysfunction amidst an inflammatory milieu. Even though considerable knowledge is available on the pathophysiology and clinical management of CP, relatively much less is known about the molecular events leading to β-cell dysfunction. Investigators have demonstrated that altered morphology, reduced β-cell mass, and β-cell numbers result in endocrine insufficiency. However, recent reports and our observations suggest that β-cell dysfunction develops in the early stages of CP while clinical diabetes manifests later, when there is profound fibrosis. In the early stages, altered internal milieu and physiology arising due to inflammation and release of cytokines might lead to deranged signaling pathways and islet dysfunction. Subsequently, development of fibrosis causes islet destruction. This suggests that endocrine deficiency in CP is multifactorial. Although the role of transcription factors (Pdx-1, MafA, NeuroD) on β-cell functions is understood, alterations in internal milieu of pancreatic tissue that affects β-cell functions in CP has not been elucidated. In this review, we summarize the factors that have an effect on islet functions. Understanding molecular events of β-cell dysfunction in CP can lead to the development of targeted preventive and therapeutic modalities.

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.

Dysfunction of the pancreas in healthy smoking persons and patients with chronic pancreatitis

OBJECTIVES

The aim of the study was to assess the effect of cigarette smoking on the endocrine pancreatic function by determining the levels of serum glucose and plasma insulin as well as by defining immunohistochemical localization of insulin and glucagon in tissue specimens of the pancreata derived from healthy persons and smoking and nonsmoking patients with diagnosed chronic pancreatitis (CP).

METHODS

The oxidative method was used to measure fasting glycemia in blood plasma and the method enzyme-linked immunoassay to determine the level of insulin in plasma. Immunohistochemical localization of hormones in paraffin tissue specimens of the pancreas was performed using the LSAB2-HRP visual test with polyclonal insulin and glucagon antibodies. The intensity of immunohistochemical reaction was calculated with digital imaging methodology.

RESULTS

The study revealed a substantially higher level of serum glucose in smoking CP patients and in healthy persons compared with nonsmoking patients and healthy persons, whereas insulin concentration in smoking patients was statistically lower than in nonsmokers. Smoking patients showed significantly lower expression of insulin and glucagon in the pancreas compared with nonsmoking patients and healthy persons.

CONCLUSIONS

Impairment of the endocrine function of beta and alpha cells in the pancreatic islets is frequently manifested by complications in pancreatitis resulting among others from long-term smoking.

Histomorphology and ultrastructure of pancreatic islet tissue during in vivo maturation of rat pancreas

In this study, we have investigated the structural and ultrastructural features of pancreatic islet tissue during rat postnatal development. For this purpose, we used neonatal (1-2 days old), young (21 days old) and adult (3-4 months old) rats. From a functional point of view, neonatal islet tissue displayed a relatively poor insulin secretory response to glucose stimulation in comparison with the adult ones. Histological analysis showed that neonatal islet cells display a less organized morphology in comparison with the young and adult ones, characterized by a less defined form and the presence of ductal structures within or nearby the islet. Regarding the islet cytoarchitecture, no differences were observed among all animal groups studied. B-cells were always typically detected within the islet core while A-cells occupied the islet periphery area. No marked differences were found during postnatal animal development regarding the ultrastructural aspect of the endocrine cells and their secretory granules. Nevertheless, quantitative analysis showed a lower B-cell/non-B-cell ratio, a higher association with ducts and an increased immunoreaction for proliferating cell nuclear antigen (PCNA) in neonatal islets as compared to young and adults. In conclusion, the acquisition of an adult pattern of insulin secretion may require an appropriate histoarchitecture and B-cell/non-B-cell proportion that may affect crucial regulatory events such as the paracrine and/or the cell-cell interaction or communication within the islet.

Cyclooxygenase 2 expression in chronic pancreatitis: correlation with stage of the disease and diabetes mellitus

BACKGROUND

Fibrotic replacement of the exocrine pancreatic parenchyma and infiltration of inflammatory cells are the main characteristics of chronic pancreatitis (CP). Inflammation involves prostaglandin production in numerous inflammatory and noninflammatory cells, and cyclooxygenase 2 (COX-2) is the dominant regulator of prostaglandin synthesis.

AIMS

In the present study, we analyzed the expression of COX-2, the key enzyme for prostaglandin synthesis in pancreatic tissues, and evaluated its relation to exocrine and endocrine tissue alterations in CP.

PATIENTS AND METHODS

Pancreatic tissue specimens from 27 patients undergoing pancreatic head resection for CP were included in the study. Pancreatic tissues from 14 organ donors served as controls. The tissue specimens were analyzed histopathologically and for COX-2 immunoreactivity.

RESULTS

In normal pancreatic tissue samples, COX-2 immunoreactivity was restricted to islet cells. In contrast, in early-stage CP, islets as well as ductal cells showed intense COX-2 immunoreactivity. In advanced-stage CP, ductal cells were still strongly positive for COX-2, yet islets displayed a variable COX-2 staining pattern which was associated with the distribution of insulin-positive cells and with the clinical diabetes mellitus status of the patient. Thus, patients with normal or latent diabetes mellitus status showed COX-2 immunoreactivity, whereas in diabetic patients the COX-2 immunoreactivity was decreased or absent in pancreatic islets.

CONCLUSION

The presence of COX-2 in ductal cells of early and advanced CP, the relationship between COX-2 and insulin expression in the islets, and the diabetes mellitus status of CP patients suggest that this enzyme plays a role in the pathogenesis of exocrine and endocrine damage in CP.