Linked Life Data

15881419

Source:http://linkedlifedata.com/resource/pubmed/id/15881419

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2-3
pubmed:dateCreated
2005-5-9
pubmed:abstractText
The transplantation of encapsulated islets of Langerhans is one approach to treat type 1 diabetes without the need of lifelong immunosuppression. Capillaries have been used for macroencapsulation because they have a favorable surface-to-volume ratio and because they can be refilled. It is unclear at present whether the outer surface of such capillaries should be smooth to prevent, or rough to promote, cell adhesions. In this study we tested a new capillary made of modified polysulfone (MWCO: 50 kDa) with a rough, open-porous outer surface for islet transplantation. Compared with free-floating islets, encapsulation of freshly isolated rat islets affected neither the kinetics nor the efficiency of glucose-induced insulin release in perifusion experiments. Free-floating islets maintained insulin secretion during cell culture but encapsulated islets gradually lost their glucose responsiveness and released VEGF. This indicated hypoxia in the capillary lumen. Transplantation of encapsulated rat islets into diabetic rats significantly reduced blood glucose concentrations from the first week of implantation. This hypoglycaemic effect persisted until explantation 4 weeks later. Transplantation of encapsulated porcine islets into diabetic rats reduced blood glucose concentrations depending on the islet purity. With semipurified islets a transient reduction of blood glucose concentrations was observed (2, 8, 18, 18 days) whereas with highly purified islets a sustained normoglycaemia was achieved (more than 28 days). Explanted capillaries containing rat islets were covered with blood vessels. Vascularization was also observed on capillaries containing porcine islets that were explanted from normoglycaemic rats. In contrast, on capillaries containing porcine islets that were explanted from hyperglycemic rats a fibrous capsule and lymphocyte accumulations were observed. No vascularization on the surface of transplanted capillaries was observed in the absence of islets. In conclusion, encapsulated islets can release VEGF, which appears to be an important signal for the vascularization of the capillary material. The rough, open-porous outer surface of the polysulfone capillary provides a site well suited for vascular tissue formation and may allow a prolonged islet function after transplantation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0963-6897
pubmed:author
pubmed:issnType
Print
pubmed:volume
14
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
97-108
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:15881419-Animals, pubmed-meshheading:15881419-Biocompatible Materials, pubmed-meshheading:15881419-Diabetes Mellitus, Experimental, pubmed-meshheading:15881419-Female, pubmed-meshheading:15881419-Graft Survival, pubmed-meshheading:15881419-Islets of Langerhans, pubmed-meshheading:15881419-Membranes, Artificial, pubmed-meshheading:15881419-Neovascularization, Physiologic, pubmed-meshheading:15881419-Pancreas, Artificial, pubmed-meshheading:15881419-Polymers, pubmed-meshheading:15881419-Prostheses and Implants, pubmed-meshheading:15881419-Rats, pubmed-meshheading:15881419-Rats, Inbred Lew, pubmed-meshheading:15881419-Sulfones, pubmed-meshheading:15881419-Sus scrofa, pubmed-meshheading:15881419-Transplantation, Homologous, pubmed-meshheading:15881419-Vascular Endothelial Growth Factor A
pubmed:year
2005
pubmed:articleTitle
Encapsulation of islets in rough surface, hydroxymethylated polysulfone capillaries stimulates VEGF release and promotes vascularization after transplantation.
pubmed:affiliation
Department of Pharmacology, Institute of Pharmaceutical Sciences, Auf der Morgenstelle 8, University of Tübingen, 72076 Tübingen, Germany. nicolas.lembert@uni-tuebingen.de
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't