Design of a polyurethane membrane for the encapsulation of islets of Langerhans

Zondervan, G; Hoppen, Hj; Pennings, A. J.; Fritschy, Wm; Wolters, G. H. J.; Vanschilfgaard, R

doi:10.1016/0142-9612(92)90061-r

Cited by 29 publications

(6 citation statements)

References 25 publications

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“…Thermoplastic materials that are currently used for cell immunoprotection are polyacrylonitrile and polyvinyl chloride copolymers (PAN/PVC or Amicon ; hollow fibers)(97, 113, 168, 169), polyurethane (PU) and polyurethane and polyvinyl pyrrolidone copolymers (PU/PVP) (macrocapsules)(170, 171), PU (membranes)(172), polysulfone (hollow fibers)(173, 174), AN69 renal dialysis membranes (69% acrylonitrile and 31% sodium methallyl sulphonate) modified by electrical discharges(175), polytetrafluoroethylene (PTFE) membranes(98, 99, 176, 177), dual porosity nylon membrane(178). ..…”

Section: Current Immunoprotective Membrane Designsmentioning

confidence: 99%

Membranes to achieve immunoprotection of transplanted islets

2014

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Transplantation of islet or beta cells is seen as the cure for type 1 diabetes since it allows physiological regulation of blood glucose levels without requiring any compliance from the patients. In order to circumvent the use of immunosuppressive drugs (and their side effects), semipermeable membranes have been developed to encapsulate and immunoprotect transplanted cells. This review presents the historical developments of immunoisolation and provides an update on the current research in this field. A particular emphasis is laid on the fabrication, characterization and performance of membranes developed for immunoisolation applications.

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Section: Current Immunoprotective Membrane Designsmentioning

confidence: 99%

Membranes to achieve immunoprotection of transplanted islets

2014

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“…7,8,[14][15][16][17][18] Nonselective permeability (cytokines and antibodies), implant degradation, and limitation of nutrient diffusion are also reported as major causes of encapsulated islet dysfunction. 19 Although several materials have been assessed (agarose, chitosan, copolymers of acetonitrile, AN69, poly(2hydroxyethyl methacrylate), polyurethane, monomethoxy poly(ethylene glycol), and Biodritin), [20][21][22][23][24][25][26] alginate is currently the main material used in the field of islet transplantation to provide immunoisolation to encapsulated cells. [27][28][29][30][31] This material, extracted from brown alga, is a polysaccharide composed of subunits of mannuronic (M) and guluronic (G) acids.…”

Section: Introductionmentioning

confidence: 99%

In Vivo Selection of Biocompatible Alginates for Islet Encapsulation and Subcutaneous Transplantation

Vériter

Mergen

Goebbels

et al. 2010

Tissue Engineering Part A

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Islet encapsulation requires several properties including (1) biocompatibility, (2) immunoprotection, and (3) oxygen diffusion for islet survival and diabetes correction. New chemical alginates were tested in vivo and compared with traditional high-mannuronate and -guluronate alginates. New alginates with coupled peptide sequence (sterile lyophilized high mannuronate [SLM]-RGD3% and sterile lyophilized high guluronate [SLG]-RGD3%), to improve encapsulated cell adherence in the matrix, and alginates with a very low viscosity (VLDM7% and VLDG7%), to reduce implant size by loading a higher number of islets per volume of polymer, were implanted subcutaneously in 70 Wistar rats for comparison with alginates of high viscosity and high content of mannuronic (SLM3%) or guluronic acids (SLG3%). Permeability of alginates to 36-, 75-, and 150-kDa lectins coupled to fluorescein isothiocynate was quantified before implantation and at 2, 4, and 12 weeks after implantation. Biocompatibility (fibrosis, graft stability, immunologic infiltration by CD3/CD68 cells, and neovascularization) was assessed at each explantation time. Permeability to small molecules was found for all alginates. Impermeability to 150-kDa molecules, such as IgG, was observed only for SLM3% before implantation and was maintained up to 12 weeks after implantation. SLM3% and SLG3% demonstrated better graft stability with lower CD3/CD68 recruitment and fibrosis than the other alginates. SLM3% induced a significantly higher angiogenesis and maintained oxygen pressure at approximately 40 mm Hg for up to 4 weeks after implantation as measured by in vivo electronic paramagnetic resonance oximetry. SLM-encapsulated pig islets implanted subcutaneously in rats demonstrated no inflammatory/immunologic reactions and islets functioned for up to 60 days without immunosuppression. A traditional alginate made of high mannuronic content (SLM3%) is an adapted material to immunoprotect islets in subcutaneous tissue. No improvement was found with lower viscosity and use of GRGDSP-peptide sequence.

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“…Permeability of immunoisolation devices has been measured either by indirect measurements of solute entry or by detection of solute inside immunoisolation devices 8,22,23 . Most permeability studies have been performed with microcapsules 24–33 . Measurements of capsule permeability have been conducted with either individual capsules using confocal 34 or fluorescence microscopy 31 or with a batch of capsules using UV spectrophotometry 32,35 and HPLC 36 to detect a decrease/increase of the solute concentration in surrounding medium.…”

Section: Resultsmentioning

confidence: 99%