Islet porcine

J1 C, Xie D, Mays J et al (2004) A novel approach to xenotransplantation combining surface engineering and genetic modification of isolated adult porcine islets. Surgery 136 537-547... 

Benhamou, P. Y., Moriscot, C., Richard, M. J., Kerr-Conte, J., Pattou, F., Chroboczek, J., Lemarchand, P. and Halimi, S. (1998). Adenoviral-mediated catalase gene transfer protects porcine and human islets in vitro against oxidative stress. Transplant Proc. 30, 459. 

Pancreastatin, a peptide isolated from porcine pancreas, inhibits insulin secretion and pancreatic secretion in vivo. It also inhibits insulin release from rat pancreatic islets and Ca2+ uptake in response to glucose without affecting K+ efflux (Lindskog et al., 1992), suggesting modulation of insulin release at the level of Ca2+ entry. 

The vertebrate NPY family contains such prominent members as pancreatic polypeptide (PP), characterized initially from chicken where PP is synthesized and released from the endocrine cells of the pancreatic islets [204], neuropeptide Y (NPY) found in porcine brain [205] and peptide YY (PYY) isolated from porcine intestine [206]. Such peptides are characterized by a chain length of 36 amino acids and Tyr-amide at the C-terminus. Whereas NPY is exclusively expressed in neurons of mammals and is known to control processes such as stimulation of food intake, vasoconstriction, sexual behaviour and circadian rhythm, PP and PPY are synthesized in endocrine cells of the gut and are inhibitors of gut motility and of the secretion of exocrine products from the pancreas. 

Luc J. W. van der Laan, Christopher Lockey, Bradley C. Griffeth, Francine S. Frasier, Carolyn A. Wilson, David E. Onions, Bernard J. Hering, Zhifeng Long, Edward Otto, Bruce E. Torbett and Daniel R. Salomon, Infection by porcine endogenous retroviras after islet xenotransplantation in SCID mice. Nature, 207 (2000), 90-94. 

Xie D, Smyth C A, Eckstein C, et al. (2005). Cytoprotection of PEG-modified adult porcine pancreatic islets for improved xenotransplantation. Biomaterials. 26 403-412. 

Lanza, R.R Kiihtreiber, W.M. Ecker, D. Staruk, J.E. Chick, W.L. Xenotransplantation of porcine and bovine islets without immunosuppression using uncoated alginate microspheres. Transplantation 1995, 59 (10), 1377-1384. 

Hill, R. S., Cruise, G. M., Hager, S. R., Lamberti, F. V., Yu, X., Garufis, C. L., Yu, Y. etal. Immunoisolation of adult porcine islets for the treatment of diabetes mellitus. The use of photopolymerizable polyethylene glycol in the conformal coating of mass-isolated porcine islets. Annals of the New York Academy of Sciences. 1997, 831, 332-343. 

The analysis of a hybrid bioartificial membrane pancreas (HBMP) in which porcine islets of Langerhans were segregated in the shell side of a hollow fibre module, showed the importance of convective fluxes in determining reactor performance. A distributed parameter model, taking into account... 

Evidence assembled in human islet tumors, in rat islet cells, and in fetal bovine slices has established the existence of a proinsulin, a precursor of insulin. The amino acid sequences of porcine and bovine proinsulin are known NH2B chain Arg-Arg-C peptide Lys-Arg-A chain COOH (see Fig. 8-31). The C peptide forms the connecting unit in human proinsulin and is composed of 31 amino acids. Proinsulin is synthesized in the endoplasmic reticulum, transferred to the cisterna, and from there to the Golgi. Where the proinsulin is converted to insulin is unknown, but it has been suggested that the precursor is broken down into separate chains in the Golgi apparatus. After proteolysis of proinsulin, both proinsulin and the C peptide are stored in the zymogen granule. 

Chronic Diseases. Xenotransplantation has the potential to treat many chronic diseases that cause cell death. For example, in diabetes, pancreatic cells that produce insuhn are destroyed. Encapsulation is being tested as a means of introducing porcine islet cells (pancreatic cell structures from pigs) into human patients with diabetes. The encapsulated porcine cells help these patients produce the insulin that they would otherwise have to inject into themselves. 

Cruise, G.M., Hegre, O.D., Scharp, D.S., HubbeU, J.A., 1998. A sensitivity study of the key parameters in the interfacial photopol3fmerization of poly(ethylene glycol) diacrylate upon porcine islets. Biotechnol. Bioeng. 57, 655—665. 

Progress in the Insulin field has been rapid in these two years, particularly in the axea, of the blos thesis of the hormone. It is now well established that Insulin, which has two peptide chains (A, 21 amino acids and B, 30 amino acids) cross-linked by two disulfide bridges, is synthesized as a single peptide chain, prolnsulin. in which the A and B chains of inmUn are connected by a "connecting peptide" (C-peptide) chain of 33 (porcine) or 30 (bovine) amino acids. Work on prolnsulin has be reviewed, 1, 10 and the amino acid sequences of bovine and porcine proinsulins have been published. Hie amino acid composition of cod proinsulin has a o appeared Two different proinsulins have been demonstrated in the rat, 8 aod proinsulin has been Isolated from human islet cell tumor tissue cultures. The structures of porcine and bovine prolnsulins are as follows ... 

Bivalent cations (Ca2+,Ba2+,Sr2+) Porcine islets (neonatal, adult) Mice Diabetes [8, 25, 27-29]... 

Porcine islets are at present receiving the greatest attention since pigs produce an insulin which is structurally very similar to human insulin and pigs are, on the other hand, the only large animals slaughtered in sufficient quantities to supply the estimated demand from type I... 

Sun Y, Ma X, Zhou D, Vacek, Sun A. Normalization of diabetes in spontaneously diabetic cynomologus monkeys by xenografts of microencapsulated porcine islets without immunosuppression. J Clin Invest 1996 98 1417-1422. 

Cruise, G. M., Hegre, O. D., Lamberti, F. V. et aL 1999. In vitro and in vivo performance of porcine islets encapsulated in interfacially photopolymerized poly(ethylene glycol) diacrylate membranes. Cell Transplant 8 293-306. 

Insulin is produced in the islets of Langerhans in the pancreas. The name comes from the Latin insula meaning island. Its structure varies slightly between species porcine insulin is especially similar to the human version. Insulin is produced and stored in the body as ahexamer [a unit of six insulin molecules, connected by Zn ions (Figure 3.8), while the active form is the monomer. The hexamer is an inactive form with long-term stability, which serves as a way to keep the highly reactive insulin protected, yet readily available. 

MacKenzie DA, Hullett DA, Sollinger HW. (2003) Xenogeneic transplantation of porcine islets an overview. Transplantation 76(6) 887. 

---