Thomas Gasslander

Islet amyloid polypeptide tonally inhibits β-, α-, and δ-cell secretion in isolated rat pancreatic islets

Islet amyloid polypeptide (IAPP, or amylin) is produced in pancreatic beta-cells. The intraislet significance of IAPP is still uncertain. In the present study, paracrine effects of endogenous IAPP and somatostatin were investigated in isolated rat pancreatic islets. The intraislet IAPP activity was inhibited with an IAPP antiserum or a specific antagonist [IAPP-(8-37)]. Somatostatin activity was inhibited by immunoneutralization. Basal insulin and glucagon secretion were not affected by the somatostatin and/or IAPP blockade. Arginine-stimulated insulin and glucagon secretion were dose dependently increased by IAPP antiserum, IAPP-(8-37), and somatostatin antiserum, respectively. Arginine-stimulated somatostatin secretion was dose dependently potentiated by IAPP antiserum. Insulin secretion induced by 16.7 mM glucose was enhanced by IAPP antiserum and IAPP-(8-37), respectively. A combination of somatostatin antiserum with IAPP antiserum or IAPP-(8-37) further enhanced the arginine-stimulated insulin and glucagon secretion compared with effects when the blocking reagents were used individually. These results indicate that endogenously produced IAPP tonally inhibits stimulated insulin, glucagon, and somatostatin secretion. Furthermore, the paracrine effects of IAPP and somatostatin are additive.

Dissociated secretion of islet amyloid polypeptide and insulin in serum-free culture media conditioned by human pancreatic adenocarcinoma cell lines

SummaryConclusionThe cosecretion of insulin and islet amyloid polypeptide (IAPP) is altered when isolated rat pancreatic islets are incubated in culture media conditioned by human pancreatic cancer cells.BackgroundPancreatic cancer is usually associated with impaired glucose tolerance. This study investigates the tumor-derived influence on β-cell secretion of pancreatic islets.MethodsFour conditioned media were prepared from two human pancreatic cancer cell lines (Panc-1 and HPAF), a hamster pancreatic cancer cell line (PC-1), and a fibroblast cell line (Ag1523). Isolated rat pancreatic islets were incubated first in the conditioned media or nonconditioned control medium for 24 h, then in the same kind of media containing 100 μM carbamylcholine for 90 min. Insulin and IAPP secretion were measured by radioimmunoassay.ResultsIslets in media conditioned by Panc-1 and HPAF cells demonstrated dissociation of insulin and IAPP secretion. During 24-h incubation, the dissociation was expressed as selectively decreased insulin secretion. With addition of 100 μM carbamylcholine, the dissociation was expressed as normal secretion of insulin and hypersecretion of IAPP. As a result, the IAPP/insulin molar ratios were increased in both groups during both time periods. The islets in PC-1 and Ag1523 media did not show any significant changes in insulin and IAPP secretion.

Cystic Tumors of the Pancreas

The discovery of a cystic lesion in the pancreas implies a challenge for the physician. Approximately 10% are cystic tumors, benign to highly malignant, or true cysts, showing all stages of cellular differentiation, from benign to highly malignant tumors. Malignant cystic tumors are rare and comprise only about 1% of all pancreatic malignancies, they are potentially curable. Therefore, correct diagnosis and treatment of these lesions are of great importance. It is usually not possible to separate a pseudocyst from a benign cyst or a cystic tumor, but there are some signs and findings that could be helpful in the clinical decision. The diagnosis of a cystic pancreatic tumor requires different imaging techniques, including ultrasonography, computerized tomography, magnetic resonance imaging, and magnetic resonance cholangiopancreatography, but to distinguish a pseudocyst or a benign cyst from a potentially malignant lesion can be very difficult. The usefulness of blood tests and investigations of cyst fluid can be questionable. Today, surgical treatment of cystic pancreatic tumors can be performed with low morbidity. Therefore, we conclude that an active strategy with resection of cystic tumors of the pancreas should be recommended.

In Situ Split of the Liver When Portal Venous Embolization Fails to Induce Hypertrophy: A Report of Two Cases

Introduction. Associated liver partition and portal vein ligation for staged hepatectomy (ALPPS) has been reported as an efficient alternative to portal vein embolization (PVE) to induce growth of the future liver remnant (FLR). This method combines portal vein ligation with splitting of the liver parenchyma. Although shown to be efficient in introducing growth of the FLR and allowing for resection of the deportalized part of the liver one to two weeks after the first operation, this approach carries a significant mortality. Presentation of Case. ALPPS was applied to two elderly patients where PVE failed to stimulate sufficient growth of the FLR. In both cases, subsequent growth of the FLR allowed for successful resection of the liver lesions. The postoperative course was uneventful for both patients. Discussion. In both cases, the growth of the FLR was similar to what was previously reported when ALPPS has been performed, both patients underwent radical resections that would probably not have been safe after only the PVE. Conclusion. ALPPS used as rescue technique when PVE fails to stimulate sufficient growth of the FLR can be expected to deliver similar results as ALPPS “Up front”. These cases also suggest that ALPPS is applicable to the elderly population.

Dissociated insulin and islet amyloid polypeptide secretion from isolated rat pancreatic islets cocultured with human pancreatic adenocarcinoma cells.

Abnormal insulin and islet amyloid polypeptide (IAPP) secretion are usually seen in patients with exocrine pancreatic cancer. The beta-cell dysfunction is a characteristic of the glucose intolerance found in pancreatic cancer patients. The effects of pancreatic cancer cells on insulin and IAPP secretion from beta cells are unclear. In this study, isolated rat pancreatic islets were cocultured with two human pancreatic adenocarcinoma cell lines (Panc-1 and HPAF) and a human colonic adenocarcinoma cell line (HT-29). As a control, islets were incubated in the absence of malignant cells. The accumulation of insulin and IAPP in culture media was measured by radioimmunoassay. Output of insulin and IAPP was decreased in islets cocultured with each malignant cell line. Molar ratio of secreted IAPP and insulin (IAPP/insulin) was increased in the islets cocultured with Panc-1 or HPAF cells, but not HT-29 cells. The decreased insulin and IAPP secretion were partly recovered after Panc-1, HPAF, or HT-29 cells were removed. The IAPP/insulin ratio was normalized after the removal of Panc-1 or HPAF cells. This study indicates that insulin and IAPP secretion are altered by the human adenocarcinoma cells investigated. The impairment induced by pancreatic adenocarcinoma cells is associated with a hypersecretion of IAPP relative to insulin on a molar basis.

Serum amino acid profile in patients with acute pancreatitis

Summary.Patients in the early phase of acute pancreatitis (AP) have reduced serum levels of arginine and citrulline. This may be of patho-biological importance, since arginine is the substrate for nitric oxide, which in turn is involved in normal pancreatic physiology and in the inflammatory process. Serum amino acid spectrum was measured daily for five days and after recovery six weeks later in 19 patients admitted to the hospital for acute pancreatitis. These patients had abnormal levels of most amino acids including arginine, citrulline, glutamine and glutamate. Phenylalanine and glutamate were increased, while arginine, citrulline, ornithine and glutamine were decreased compared to levels after recovery. NO2/NO3 concentration in the urine, but not serum arginase activity, was significantly increased day 1 compared to day 5 after admission. Acute pancreatitis causes a disturbance of the serum amino acid spectrum, with possible implications for the inflammatory process and organ function both in the pancreas and the gut. Supplementation of selected amino acids could possibly be of value in this severe condition.

Proliferative Response of Different Exocrine Pancreatic Cell Types to Hormonal Stimuli

The trophic effect on the exocrine pancreas of the cholecystokinin analogue cerulein was studied in a long-term experiment (20 or 160 micrograms/kg/24 h for 14 days) in mice by measuring changes in pancreatic weight and protein, amylase, and DNA content. Further, the selective cell growth stimulation exerted by various doses of cerulein (4, 20, 54, 160 micrograms/kg/24 h) on different exocrine pancreatic cell types was studied by continuous administration of 3H-thymidine. In the first experiment animals given 20 micrograms/kg/24 h of cerulein had increased pancreatic weight and amylase and protein content, whereas the animals given the higher dose had unchanged weight and a less pronounced increase in amylase and protein content. The pancreatic DNA content was unaffected in the 20-micrograms group but was clearly decreased by the higher dose. In the second experiment a statistically significant increase over controls was found in the fraction of labeled ductal cells when 20, 54, and 160 micrograms of cerulein was administered. However, in the acinar cell population an increase was measured only in the 160-micrograms group. A tendency to nadir in cell labeling was observed in both acinar and ductal cell groups at less stimulation. Labeling of centroacinar cells increased in all cerulein-treated groups. The results show that all cell types of the exocrine pancreas can be forced into proliferation by the cholecystokinin analogue used and that there is preferential cell growth stimulation in the ductal and centroacinar cell populations.

Associating liver partition and portal vein ligation for staged hepatectomy in patients with colorectal liver metastases - Intermediate oncological results

BACKGROUND Colorectal liver metastases (CRLM) not amenable for resection have grave prognosis. One limiting factor for surgery is a small future liver remnant (FLR). Early data suggests that associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) effectively increases the volume of the FLR allowing for resection in a larger fraction of patients than conventional two-stage hepatectomy (TSH) with portal vein occlusion (PVO). Oncological results of the treatment are lacking. The aim of this study was to assess the intermediate oncological outcomes after ALPPS in patients with CRLM. MATERIAL AND METHODS Retrospective analysis of all patients with CRLM operated with ALPPS at the participating centres between December 2012 and May 2014. RESULTS Twenty-three patients (16 male, 7 female), age 67 years (28-80) were operated for 6.5 (1-38) metastases of which the largest was 40 mm (14-130). Six (27.3%) patients had extra-hepatic metastases, 16 (72.7%) synchronous presentation. All patients received chemotherapy, 6 cycles (3-25) preoperatively and 16 (70%) postoperatively. Ten patients (43%) were rescue ALPPS after failed PVO. Severe complications occurred in 13.6% and one (4.5%) patient died within 90 days of surgery. After a median follow-up of 22.5 months from surgery and 33.5 months from diagnosis of liver metastases estimated 2 year overall survival was 59% (from surgery) and 73% (from diagnosis). Liver only recurrences (n = 8), were treated with reresection/ablation (n = 7) while lung recurrences were treated with chemotherapy. CONCLUSION The overall survival, rate of severe complications and perioperative mortality associated with ALPPS for patients with CRLM is comparable to TSH.

Cholecystokinin octapeptide induces both proliferation and apoptosis in the rat pancreas

Cholecystokinin-8 (CCK-8) causes exocrine pancreatic hypertrophy and hyperplasia. High doses of the CCK analogue cerulein causes necrosis and an inflammatory response in the pancreas. We have studied the pancreatic growth response in rats after administration of CCK-8 for 3 days, given either intermittently (20-80 microg/kg) twice a day, or continuously (2.4-48 microg/kg per 24 h). Plasma CCK-8 levels, pancreatic wet weight, water, protein and DNA contents and the pancreatic caspase-3 activity were measured. Cell proliferation was visualized by [3H]thymidine incorporation and apoptosis by TUNEL reaction. Continuous administration of CCK-8 dose-dependently increased the plasma CCK levels, the pancreatic wet weight, protein and DNA contents as well as thymidine labeling index, apoptotic index and caspase-3 activity. Intermittent injections of CCK-8 caused transient raises in plasma CCK, increased apoptotic index and caspase-3 activity, a dose-dependent increase in thymidine labeling but caused a dose-dependent reduction of pancreatic wet weight, protein, and DNA contents. It is concluded that CCK-8 causes both increased proliferation and apoptosis in the pancreas. In case of continuous administration of CCK-8, the proliferation outweighs the apoptosis causing hyperplasia but in the case of intermittent administration the opposite effect is seen.

Proliferative Response of Different Exocrine Pancreatic Cells after Surgical Pancreaticobiliary Diversion in the Rat

Pancreaticobiliary diversion (PBD) is known to induce chronic, endogenous hypercholecystokininemia causing pancreatic growth in rats. In the present study the proliferative response of the different exocrine pancreatic cells was studied by administration of 3H-thymidine, 1 mCi/kg, given 1 h before the rats were killed and 5, 10, 20, and 40 days after PBD. DNA and 3H-thymidine uptake, both expressed per 1 mg of pancreatic tissue, were significantly increased on day 5. The nuclear labeling index was increased fivefold in both the acinar and ductal cell group. In the centroacinar cell group the labeling index was increased on day 10. In conclusion, we found that the proliferative activity after PBD occurred during the first 10 days and that the ductal cells were forced into proliferation to the same extent as the acinar ones. These findings are of interest for future studies of hormonal influences on the development of pancreatic carcinoma.