No abstract available.
Exocytosis/physiology* ; Pancreas/secretion ; Pancreas/physiology* ; Pancreas/cytology*

No abstract available.
Animal ; Calcium Signaling/physiology* ; Exocytosis/physiology ; Pancreas/physiology* ; Pancreas/cytology

OBJECTIVETo understand and improve the transdifferentiation of pancreatic stem cells into islet cells through isolation, cultivation and transdifferentiation of adult human pancreatic duct cells.

METHODSA portion of adult human pancreas was digested with collagenase, followed by incontinuous density gradient to separate islets from the acinar and ductal tissue. Duct epithelial cells were cultivated in CMRL1066 and then in serum-free DMEM/F12 medium with the addition of growth factors for 27 days. Samples were taken at different time points for light and electron microscopic examination and for immunocytochemical study with antibodies against transdifferentiation gene PDX-1 and protein CK-19. Amylase and insulin contents in the medium were assayed.

RESULTSA large number of duct epithelial cells were harvested after the isolation of islets. Some duct epithelial cells were PDX-1 and CK-19 positive at day one and duct epithelial cells proliferated and expanded rapidly and then transdifferentiated into stem cells and finally 3D islets. 760 islets were harvested from each gram of pancreatic tissue on day 27.

CONCLUSIONSAdult pancreatic duct cells are potential stem cells and could be transdifferentiated into islet cells in vitro under appropriate conditions.

Adult ; Cell Differentiation ; physiology ; Humans ; Islets of Langerhans ; cytology ; Pancreas ; cytology ; Stem Cells ; cytology

Methonexate is one of the well known anti-cancer chemotherapeutic agents and exerts its action by inhibiting mitoses by inhibition of nucleic acid synthesis. Its effect on actively proliferating normal and pathologic tissues have been well documented. However, little information is available on its effect on tissue which shows no active mitoses but does have a very active metabolic process, such as the pancreas. The present study investigated the histochemical and ultrastructural changes which take place within 24 hours after a single intraperitoneal injection of methotrexate. Using a light microscope for observation, no .specific or constant alteration was noted except for a mild acinar cell dissociation 18 hours after the injection. However, electron microscopic observations showed that several organelles of pancreatic acinar cell revealed ultrastructural changes such as vesiculation and dilation of the cisternae of endoplasmic reticulum, and the appearance of autophagic vacuoles which contained cellular organelles, and showed hyperplasia and dilation of Golgi complexes. The nuclei and zymogen granules were not significantly altered. The changes of endoplasmic reticulum were ,distinctly seen from 1 hour after the injection and were most severe at 6 hours. Autophagic vacuoles appeared at 6 hours and had progressively increased in number and size 18 hours after the injection. Similar changes were also reported in experimental animals which were treated with several cytotoxic agents. According to this study, it is evident that a single administration of methotrexate within short time interval induced a series of ultrastructural alterations in several organelles of the pancreatic acinar cells. It is not clear as yet whether or not this is a specific reaction of cells to methotrexate.
Animals ; Female ; Male ; Methotrexate/*pharmacology ; Pancreas/cytology/*drug effects ; Rats

Reactive oxygen species (ROS), generated by infiltrating neutrophils, are considered as an important regulator in the pathogenesis and deveolpment of pancreatitis. A hallmark of the inflammatory response is the induction of cytokine gene expression, which may be regulated by oxidant-sensitive transcription factor, nuclear factor-kappaB (NF-KB). Present study aims to investigate whether neutrophils primed by 4beta-phorbol 12beta-myristate 13alpha-acetate (PMA) affect the productions of H2O2 and lipid peroxide (LPO), NF-kappaB activation and cytokine production in pancreatic acinar cells, and whether these alterations were inhibited by N-acetylcysteine (NAC) and superoxide dismutase (SOD). ROS generation in neutrophils increased by PMA, which was inhibited by NAC and SOD. The productions of H2O2, LPO and TNF-alpha were increased with the amounts of PMA-primed neutrophils added to acinar cells while the productions of H2O2, LPO and cytokines increased with time. PMA-primed neutrophils resulted in the activation of two species of NF-kappaB dimers (a p50/p65 heterodimer and a p50 homodimer). Both NAC and SOD inhibited neutrophil-induced alterations in acinar cells. In conclusion, ROS, generated by neutrophils, activates NF-kappaB, resulting in upregulation of inflammatory cytokines in acinar cells. Antioxidants such as NAC might be clinically useful antiinflammatory agents by inhibiting oxidant-mediated activation of NF-KB and decreasing cytokine production.
Acute Disease ; Chronic Disease ; Cytokines/immunology* ; Human ; NF-kappa B/metabolism* ; Pancreas/metabolism* ; Pancreas/immunology* ; Pancreas/cytology ; Pancreatitis/metabolism ; Pancreatitis/immunology ; Support, U.S. Gov't, Non-P.H.S.

OBJECTIVETo isolate and identify the phenotype and biological characteristics of pancreas derived mesenchymal stem cell.

METHODSFresh pancreas of 4-5 months old aborted fetus was dissected free from connective tissue, and was cut into small pieces. The adherent cells were harvested and subcultured, after the third subculture, the cells were used for examination. Cell cycle was analyzed by measuring DNA content by FACScan flow cytometer. Phenotype of MSCs was analyzed by immunohistochemical SA technique and differentiated cells were identified by relevant specific staining.

RESULTSFetal pancreas derived cells gave rise to a population of adherent cells characterized by the presence of a predominant cell type with a typical fibroblast like morphology. By transmission electron microcopy, MSC had few endoplasmic reticulums and mitochondrias. During the log phase of growth, MSC proliferated with a two fold population at 30 h. MSC can be ex vivo expanded by successive cycles of trypsinization, seeding, and culture. Under these conditions, MSC had capability of passaging up to 30 times without displaying significant changes in morphology, with 2-fold increase in cell number after each passage. This indicates the high ex vivo expansion potential of MSC. The results showed that the yield of CFU-Fs was above 200 clones even after the 6th passage. Cell cycle analysis by flow cytometry revealed that more than 83% of cells were in the G0/G1 phases, while a small population of cells were actively engaged in proliferation (S + G2 + M = 17%). We also showed that more than 86% of cells were positive stained by FITC labeled CD44, CD29, CD13, and only about 1% of cells were positive for CD34, HLA-DR. Expression of collagen I, III was positive while vWF was negative. In the differentiation study, we found culture-expanded pancreas MSCs could be directed into the osteogenic lineage as detected by osteoblastic morphology, expression of alkaline phosphatase, modulation of osteocalcin mRNA production and the formation of a mineralized extracellular matrix. We also found that MSCs could give rise to the adipogenic and chondrogenic lineage as evidenced by accumulation of lipid-rich vacuoles within cells and the expression of lipoprotein lipase mRNA or the expression of collagen II and the deposition of proteoglycans.

CONCLUSIONMesenchymal stem cells existing in human pancreas can be isolated by their adherent ability and should be essential to sustain a steady supply of primitive cells in tissue remodeling.

Cell Differentiation ; Cell Division ; Cell Separation ; Cells, Cultured ; Colony-Forming Units Assay ; Fetus ; Fibroblasts ; cytology ; Humans ; Mesoderm ; cytology ; Osteogenesis ; Pancreas ; cytology ; Phenotype ; Stem Cells ; cytology

OBJECTIVETo establish a simple but effective method of laser scanning confocal microscopic imaging for Ca2+ oscillations of pancreatic acinar cells in adult mice.

METHODSPancreatic acinar cells from adult Kunming mice were isolated acutely with collagenase, and then loaded with fluo-4-AM, a Ca2+ indicator. A laser scanning confocal microscope armed with 488 nm laser was employed to record the dynamic fluorescent signals in-time and synchronously while acetylcholine (ACh) was added in the pancreatic acinar cells.

RESULTS(1) The classic pancreatic acinar cell Ca2+ oscillations were induced by a certain concentration of ACh (100 nmol/L) successfully and steadily, which could be blocked by atropine completely. (2) Plasmic Ca2+ oscillations from different parts of one acinar cell were usually with different amplitudes and almost the same frequencies. But both of amplitudes and frequencies were different among different cells. (3) The acinar cell Ca2+ oscillations were induced by ACh in a concentration-dependent manner.

CONCLUSIONThe laser scanning confocal microscopic imaging for adult mouse pancreatic acinar cell Ca2+ oscillations was established successfully. The features of being easy to use, direct to see lively, high efficiency and good flexibility make it a popular tool for researchers to choose.

Acinar Cells ; chemistry ; Animals ; Calcium ; analysis ; Calcium Signaling ; Cells, Cultured ; Mice ; Microscopy, Confocal ; methods ; Pancreas ; cytology

To attempt a rigorous definition of the structure of the accessory spleen (AS) in the Chinese hamster, we examined twenty-one animals, and found AS in 5 animals (23.8%), which were over 7-month-old. The AS had no connection with the main spleen and was seen as a dark red oval organ (0.7 mm x 1.5 mm), which was embedded in the adipose tissue near the tail of the pancreas. It was demarcated from the adipose tissue and some pancreatic tissue. The organ was encapsulated by thin collagenous connective tissue and smooth muscle fibers, and contained lymphatic nodules, reticular fibers, nodular central arterioles, macrophages and megakaryocytes. Notably the incidence of AS appeared to increase with age in the Chinese hamsters.
Adipose Tissue/anatomy & histology ; Age Factors ; Animals ; Connective Tissue/anatomy & histology ; Cricetinae ; Cricetulus/*anatomy & histology ; Erythrocytes/cytology ; Lymphocytes/cytology ; Muscle, Smooth/anatomy & histology ; Pancreas ; Spleen/*anatomy & histology/cytology

OBJECTIVETo construct a method to culture pancreatic progenitor cells in hanging drop and on floating filter,and to examine if pancreatic progenitor cells can differentiate into mature endocrine cells with this method.

METHODSMurine embryos at day 12.5 were isolated and digested into single cells,which were then cultured in hanging drop for 24h and formed spheres.Spheres were cultured on the filter for 6 days,which floated in the dish containing medium.During culture,the expressions of pancreas duodenum homeobox-1(PDX-1)and neurogenin3(Ngn3)were determined.The expressions of endocrine and exocrine markers,insulin,glucagon,and carboxypeptidase(CPA)were determined on day 7 by immunohistochemistry.Insulin secretion of spheres stimulated by glucose was detected by ELISA.The changes of pancreatic marker expressions during culture were monitored by real-time polymerase chain reaction(PCR).

RESULTSOne day after the culture,there were still a large amount of PDX-1 positive cells in pancreatic spheres,and these cells proliferated.On day 3,high expression of Ngn3 was detected,and the Ngn3-positive cells did not proliferate.On day 7,The expressions of endocrine and exocrine markers in the differentiated pancreatic progenitor cells were detected,which were consistent with that in vivo.Insulin was secreted by spheres upon the stimulation of glucose.

CONCLUSIONIn hanging drop and on floating filter,pancreatic progenitor cells can differentiate into mature endocrine cells.

Animals ; Cell Culture Techniques ; Cell Differentiation ; Cells, Cultured ; Endocrine Cells ; cytology ; Homeodomain Proteins ; metabolism ; Insulin ; metabolism ; Mice ; Pancreas ; cytology ; Stem Cells ; cytology ; Trans-Activators ; metabolism

In this study, the natural biological inducer, rat regenerating pancreatic extract (RPE), was used to induce human amniotic mesenchymal stem cells (hAMSCs) into insulin-secreting cells. We excised 60% of rat pancreas in order to stimulate pancreatic regeneration. RPE was extracted and used to induce hAMSCs at a final concentration of 20 microg/mL. The experiment methods used were as follows: morphological-identification, dithizone staining, immumofluorescence analysis, reverse transcription-PCR (RT-PCR) and insulin secretion stimulated by high glucose. The results show that the cell morphology of passge3 hAMSCs changed significantly after the induction of RPE, resulting in cluster shape after induction for 15 days. Dithizone staining showed that there were scarlet cell masses in RPE-treated culture. Immumofluorescence analysis indicated that induced cells were insulin-positive expression. RT-PCR showed the positive expression of human islet-related genes Pdx1 and insulin in the induced cells. The result of insulin secretion stimulated by high glucose indicated that insulin increasingly secreted and then kept stable with prolongation of high glucose stimulation. In conclusion, hAMSCs had the potential to differentiate into insulin-secreting cells induced by RPE in vitro.
Amnion ; cytology ; Animals ; Cell Differentiation ; physiology ; Cells, Cultured ; Humans ; Insulin-Secreting Cells ; cytology ; Mesenchymal Stromal Cells ; cytology ; Pancreas ; physiology ; surgery ; Pancreatic Extracts ; pharmacology ; Rats ; Regeneration