Sub-Areas to Isolated Islet Cells:
Functional Capability of Cells
(0)
Stimulation of Division
(1)
Endocrine Cells
(3)
Ductal Cell Sources
(4)
Cardiomyocytes
(1)
(Journal Article): Large scale isolation, growth, and function of porcine neonatal islet cells.
Korbutt GS, Elliot JF, Ao Z, Smith DK, Warnock GL, Rajotte RV (Surgical-Medical Research Institute, University of Alberta, Edmonton, Canada.)
IN:
J Clin Invest
1996; 97(9):2119-2129
Impact Factor(s) of J Clin Invest: 14.204 (2004), 14.307 (2003), 14.118 (2001)
ABSTRACT: Based upon existing methods of isolating fetal porcine islet tissue, a simple, reliable procedure was developed for the preparation of porcine neonatal islet cell aggregates with a reproducible and defined cellular composition. After 9 d of in vitro culture, tissue from one neonatal pig pancreas yielded approximately 50,000 islet cell aggregates, consisting of primarily epithelial cells (57%) and pancreatic endocrine cells (35%). During the culture period, the total beta cell mass decreased initially, but subsequently increased 1.5-fold between days 3 and 9. Transplantation of grafts consisting of 3 x 10(5) beta cells (1,000 aggregated) under the kidney capsule of alloxan-diabetic nude mice corrected hyperglycemia in 75% (10/13) of the animals, whereas, 100% (20/20) of recipients implanted with 6 x 10(5) beta cells (2,000 aggregates) achieved euglycemia within 8 wk posttransplantation. Nephrectomy of the graft bearing kidney at 14 wk posttransplantation resulted in hyperglycemia in all recipients, and examination of the grafts revealed the presence of numerous well-granulated insulin- and glucagon-containing cells. The cellular insulin content of these grafts was 20 to 30-fold higher than at the time of transplantation. These results indicate that the neonatal porcine pancrease can be used as a source of large numbers of viable islet cells, which have the potential for growth both in vitro and in vivo, and exhibit the metabolic capacity to correct diabetes in nude mice.
TYPE OF PUBLICATION: Original article
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(Journal Article): Cell loss in isolated human islets occurs by apoptosis.
Paraskevas S, Maysinger D, Wang R, Duguid TP, Rosenberg L (Department of Surgery, McGill University, and the Montreal General Hospital Research Institute, Quebec, Canada.)
IN:
Pancreas
2000; 20(3):270-276
Impact Factor(s) of Pancreas: 1.872 (2004), 1.855 (2003), 1.456 (2002), 1.567 (2001)
ABSTRACT: Purified islet allografts have largely failed to maintain long-term glucose homeostasis in human recipients, and the reasons for this are unclear. It is noteworthy, however, that islet isolation destroys or removes cellular and noncellular elements of the pancreas that could play an important role in supporting islet survival. The purpose of this study was to determine whether human islet isolation leads to the induction of programmed cell death. Human islets were enzymatically isolated from cadaveric donor pancreata using Liberase or Collagenase P, purified over a discontinuous BSA gradient, then cultured in RPMI 1640 at 37 degrees C in 5% CO2 for < or = 7 days. Islets were examined daily by routine histology and immunocytochemistry for islet hormones, DNA fragmentation [cell death; enzyme-linked immunosorbent assay (ELISA) and TUNEL assay] and for transglutaminase (TG) activity, two indicators of apoptosis. TG activity and DNA fragmentation increased by 1,000% and 1,890%, respectively (p < 0.05) This corresponded to the appearance of pyknotic nuclei on light microscopy, the presence of apoptotic bodies on electron microscopy, and the demonstration of TUNEL-positive cells. These were present primarily in a distribution that corresponded to the insulin-immunoreactive cells. At 5 days, 31.4 +/- 2.2% of islet cells were TUNEL positive. In summary, apoptosis of islet cells appears soon after islet isolation, and involves primarily the beta cell. This is the first report of apoptosis of islet cells after human islet isolation. The loss of beta-cell mass could be implicated in the failure of islet transplantation and merits further investigation.
TYPE OF PUBLICATION: Original article
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(Journal Article): Pancreas preservation by the two layer cold storage method before islet isolation protects isolated islets against apoptosis through the mitochondrial pathway.
Matsuda T, Suzuki Y, Tanioka Y, Toyama H, Kakinoki K, Hiraoka K, Fujino Y, Kuroda Y (Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kobe University, Kobe, Japan.)
IN:
Surgery
2003; 134(3):437-445
Impact Factor(s) of Surgery: 2.355 (2004), 2.611 (2003), 2.631 (2002), 2.615 (2001)
ABSTRACT: BACKGROUND: Apoptosis in isolated islets has been implicated in primary nonfunction or early graft failure after islet transplantation. Recently, pancreas preservation by the 2-layer method (TLM) before islet isolation has been proved to improve the islet yield, quality, and transplant results not only in experimental models, but also in clinical settings. We examined the influence of TLM on apoptosis of isolated islets. METHOD: Rat islets freshly isolated and after pancreas preservation by TLM or conventional cold storage in University of Wisconsin solution (UW) were examined and compared. Islet apoptosis was assessed by TUNEL and annexin V assays. The apoptosis pathways involved were investigated by measurement of caspase 3, 8, and 9 activities and by immunoblotting for total and phosphorylated c-Jun NH2-terminal kinase (JNK) and p38. RESULTS: Islet apoptosis in the UW group was significantly increased compared with the fresh and TLM groups. Both caspase 3 and 9 activities in the UW group were higher than in the fresh and TLM groups with an approximate increase of 2- to 3-fold. On the other hand, there was no significant difference in caspase 8 activity among these 3 groups. JNKs were strongly activated both in the TLM and UW groups; although they were not activated in the fresh group, p38 was activated to almost the same levels in these 3 groups. CONCLUSIONS: Pancreas preservation by TLM before islet isolation protects isolated islets against apoptosis mainly through the mitochondrial pathway. Pancreas storage before islet isolation even with TLM triggers activation of JNKs in isolated islets.
TYPE OF PUBLICATION: Original article
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(Journal Article): Phosphatidylinositol 3-kinase signaling to Akt mediates survival in isolated canine islets of Langerhans.
Aikin R, Rosenberg L, Maysinger D (Department of Surgery, McGill University, Montreal, Quebec, H3G 1A4, Canada.)
IN:
Biochem Biophys Res Commun
2000; 277(2):455-461
Impact Factor(s) of Biochem Biophys Res Commun: 2.904 (2004), 2.836 (2003), 2.935 (2002), 2.946 (2001)
ABSTRACT: The isolation of islet cells from the pancreas by enzymatic digestion causes many of these cells to undergo apoptosis. The aim of this work was to investigate the role of phosphatidylinositol 3-kinase (PI3-K)/Akt signaling in mediating the survival of isolated islets. Insulin-like growth factor-1 (IGF-I) was examined as a potential culture media supplement that could rescue isolated islets from their apoptotic fate. Western blot analysis demonstrated that Akt phosphorylation peaks 20 h after routine islet isolation. PI3-K inhibition with wortmannin abolished both basal and IGF-I-mediated Akt phosphorylation. IGF-I did not increase survival of isolated islets under normal conditions but it did have a protective effect against cytokine (TNF-alpha, IL-1beta, INF-gamma)-mediated cell death. The protective effect of IGF-I against cytokine-stimulated apoptosis was blocked by wortmannin. In addition, inhibition of basal levels of PI3-K activity caused a 31% decrease in islet survival, as shown by MTT assay. These results demonstrate that the PI3-K/Akt pathway mediates survival of isolated islets of Langerhans. Copyright 2000 Academic Press.
TYPE OF PUBLICATION: Original article
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(Journal Article): Sustained proliferation of PDX-1 (+) cells derived from human islets.
Beattie GM, Itkin-Ansari P, Cirulli V, Leibowitz G, Lopez AD, Bossie S, Mally MI, Levine F, Hayek A (Department of Pediatrics, University of California at San Diego, USA.)
IN:
Diabetes
1999; 48(5):1013-1019
Impact Factor(s) of Diabetes: 8.848 (2004), 8.298 (2003), 8.256 (2002), 7.7 (2001)
ABSTRACT: Ex vivo expansion of human beta-cells is an important step toward the development of cell-based insulin delivery systems in type 1 diabetes. Here, we report that human pancreatic endocrine cells can be expanded through 15 cell doublings in vitro for an estimated total 30,000-fold increase in cell number. We believe that the cells resulting from these cultures are of beta-cell origin, since they uniformly express the transcription factor PDX-1 (STF-1, IDX-1, IPF-1), which is initially seen only in cells positive for insulin and negative for the ductal cell marker cytokeratin (CK)-19. To rule out the possibility that PDX-1 expression might be induced by the culture conditions used here, cells from isolated human pancreatic ducts were cultured under the same conditions as the islet cells. Cells in these cultures expressed CK-19 but not PDX-1. Although the expanded beta-cells continued to express PDX-1, insulin expression was lost over time. Whether reexpression of islet-specific genes in vitro is essential for successful cell transplantation remains to be determined.
TYPE OF PUBLICATION: Original article
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