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J Biomed Mater Res A. 2017 Sep;105(9):2533-2542. doi: 10.1002/jbm.a.36101. Epub 2017 Jun 15.

Stimulation of vascularization of a subcutaneous scaffold applicable for pancreatic islet-transplantation enhances immediate post-transplant islet graft function but not long-term normoglycemia.

Author information

1
Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
2
Department of Surgery, University of California Irvine, Orange.
3
Polyganics, Groningen, The Netherlands.
4
Department of Developmental BioEngineering, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands.
5
Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands.
6
Department of Obstetrics and Gynaecology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
7
Department of Biomedical Engineering, University of California Irvine, Irvine.

Abstract

The liver as transplantation site for pancreatic islets is associated with significant loss of islets, which can be prevented by grafting in a prevascularized, subcutaneous scaffold. Supporting vascularization of a scaffold to limit the period of ischemia is challenging and was developed here by applying liposomes for controlled release of angiogenic factors. The angiogenic capacity of platelet-derived growth factor, vascular endothelial growth factor, acidic fibroblast growth factor (aFGF), and basic FGF were compared in a tube formation assay. Furthermore, the release kinetics of different liposome compositions were tested. aFGF and L-α-phosphatidylcholine/cholesterol liposomes were selected to support vascularization. Two dosages of aFGF-liposomes (0.5 and 1.0 μg aFGF per injection) were administered weekly for a month after which islets were transplanted. We observed enhanced efficacy in the immediate post-transplant period compared to the untreated scaffolds. However, on the long-term, glucose levels of the aFGF treated animals started to increase to diabetic levels. These results suggest that injections with aFGF liposomes do improve vascularization and the immediate restoration of blood glucose levels but does not facilitate the long-term survival of islets. Our data emphasize the need for long-term studies to evaluate potential beneficial and adverse effects of vascularization protocols of scaffolds.

KEYWORDS:

controlled growth factor release; islet transplantation; scaffold; type 1 diabetes; vascularization

PMID:
28470672
PMCID:
PMC5575460
DOI:
10.1002/jbm.a.36101
[Indexed for MEDLINE]
Free PMC Article

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