Protection of Islets of Langerhans From Antibodies by Microencapsulation With Alginate-Poly-L-Lysine Membranes1

Hallé, Jean‐Pierre; Bourassa, Suzanne; Leblond, François A.; Chevalier, Simone; Beaudry, M.; Chapdelaine, A.; Cousineau, S.; Saintonge, Jacques; Yale, Jean‐François

doi:10.1097/00007890-199302000-00023

Cited by 51 publications

(25 citation statements)

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“…The optimal capsule should allow free diffusion of glucose and insulin but prevent cell-mediated and humoral immunity. Indeed, it has been shown that alginate-PLL-alginate capsules prevent cell-mediated cytotoxicity (5) and are impermeable to antibodies (37). Several variables can influence the porosity of an alginate capsule.…”

Section: Capsule Properties Affecting Microencapsulated Islets Of Lanmentioning

confidence: 99%

The role of capsule composition and biologic responses in the function of transplanted microencapsulated islets of langerhans1

King¹,

Andersson

Strand

et al. 2003

Transplantation

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Section: Capsule Properties Affecting Microencapsulated Islets Of Lanmentioning

confidence: 99%

The role of capsule composition and biologic responses in the function of transplanted microencapsulated islets of langerhans1

King¹,

Andersson

Strand

et al. 2003

Transplantation

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“…Briefly, alginate beads were produced by extruding 1.8% sodium alginate (Kelco, Clark, New Jersey)-0.5% dextran blue (MW 2 × 10 6 ) into a 1.1% CaCl 2 solution. The droplets were generated with the use of an electrostatic pulse generator, 11 allowing the production of alginate-poly-L-lysine microcapsules of 326 ± 16 m or, using an air-jet system, 14 producing microcapsules of 1247 ± 120 m.…”

Section: Microcapsule Preparationmentioning

confidence: 99%

Studies on small (<350 ?m) alginate-poly-L-lysine microcapsules. III. Biocompatibility of smaller versus standard microcapsules

Robitaille¹,

Pariseau²,

Leblond³

et al. 1999

J. Biomed. Mater. Res.

103

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Microencapsulation of islets of Langerhans has been proposed as a means of preventing their immune destruction following transplantation. Microcapsules of diameters <350 microm made with an electrostatic pulse system present many advantages relative to standard microcapsules (700-1500 microm), including smaller total implant volume, better insulin kinetics, better cell oxygenation, and accessibility to new implantation sites. To evaluate their biocompatibility, 200, 1000, 1120, 1340, or 3000 of these smaller microcapsules (<350 microm) or 20 standard microcapsules (1247+/-120 microm) were implanted into rat epididymal fat pads, retrieved after 2 weeks, and evaluated histologically. The average pericapsular reaction increased with the number of small microcapsules implanted (p<0.05; 3000 vs. 200, 3000 vs. 1000, and 1000 vs. 200 microcapsules). At equal volume and alginate content, standard microcapsules caused a more intense fibrosis reaction than smaller microcapsules (p<0.05). In addition, 20 standard microcapsules elicited a stronger pericapsular reaction than 200 and 1000 smaller microcapsules (p<0.05) although the latter represented a 3.4-fold larger total implant surface exposed. We conclude that microcapsules of diameters <350 microm made with an electrostatic pulse system are more biocompatible than standard microcapsules.

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“…It is thought that the inability of encapsulated islet grafts to reproducibly achieve and maintain long-term euglycaemia is related not only to insufficient immunoprotection, but also to a variety of technical and metabolic issues, including: the encapsulation process, composition/purity of the microcapsule [12], capsule size and surface structure [13,14], poor biocompatibility [15,16], and endotoxin levels of the alginate [17,18]. Furthermore, while the addition of poly-L-lysine has been used to reduce capsule porosity [19], its addition has resulted in an increased fibrotic response [15]. Recently, it has been shown that a simple alginate capsule devoid of poly-L-lysine retains the ability to prolong graft survival and protect the graft [6].…”

Section: Introductionmentioning

confidence: 99%

Improved survival of microencapsulated islets during in vitro culture and enhanced metabolic function following transplantation

Korbutt

Mallett

et al. 2004

Diabetologia

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Aims/hypothesis. The aim of this study was to determine whether a simple alginate capsule can prolong islet survival and function during long-term tissue culture. We also wanted to observe the ability of these encapsulated islets to restore glucose responsiveness to diabetic recipients, along with the quantity of islets required to do so. Methods. We compared the recovery and metabolic function of encapsulated canine islets with that of non-encapsulated canine islets following 1, 2 or 3 weeks of tissue culture. These culture preparations were also transplanted into diabetic nude mice and compared for their ability to reverse diabetes. Furthermore, short-term cultured encapsulated and nonencapsulated islets were transplanted in varying numbers to determine the minimum dose required to normalise blood glucose and prolong recipient survival.Results. Islet recovery following 1, 2 and 3 weeks of tissue culture was significantly higher when islets were encapsulated. When these islets were recovered at 1, 2 and 3 weeks and transplanted into diabetic nude mice, survival at 100 days was 100% for all encapsulated groups, versus 66%, 33% and 33% respectively for the non-encapsulated islets. Additionally, substantially fewer short-term cultured islets were required to normalise blood glucose when the islets were encapsulated. Recipients of encapsulated islets also had significantly longer survival times than recipients of non-encapsulated preparations. Conclusions/interpretation. This study demonstrates that encapsulation of islets with purified alginate improves islet survival and function in vitro and in vivo.

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Protection of Islets of Langerhans From Antibodies by Microencapsulation With Alginate-Poly-L-Lysine Membranes1

Cited by 51 publications

References 0 publications

The role of capsule composition and biologic responses in the function of transplanted microencapsulated islets of langerhans1

The role of capsule composition and biologic responses in the function of transplanted microencapsulated islets of langerhans1

Studies on small (<350 ?m) alginate-poly-L-lysine microcapsules. III. Biocompatibility of smaller versus standard microcapsules

Improved survival of microencapsulated islets during in vitro culture and enhanced metabolic function following transplantation

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