Glycol Methacrylate Embedding of Algmate-Polylysine Microencapsulated Pancreatic Islets

Fritschy, Wm; Gerrits, Peter O.; Wolters, G. H. J.; Pasma, A.; Vanschilfgaarde, R

doi:10.3109/10520299509107311

Cited by 17 publications

(12 citation statements)

References 13 publications

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“…Therefore, samples of adherent capsules recovered by excision and nonadherent capsules were fixed in pre-cooled 2% paraformaldehyde, buffered with 0.05 m phosphate in saline (pH 7.4), and processed for glycol methacrylate (GMA) embedding [22]. Sections were prepared at 2 mm and stained with Romanovsky-Giemsa stain and applied for detecting imperfections in the capsule membrane and for determining the number of capsules with and without overgrowth.…”

Section: Microscopymentioning

confidence: 99%

Long-term biocompatibility, chemistry, and function of microencapsulated pancreatic islets

et al. 2003

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Section: Microscopymentioning

confidence: 99%

Long-term biocompatibility, chemistry, and function of microencapsulated pancreatic islets

et al. 2003

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“…25 Sections were prepared at 2 m and stained with Romanovsky-Giemsa stain and applied for detecting imperfections in the capsule membrane and for determining the number of capsules with and without overgrowth. The degree of capsular overgrowth was quantified by expressing the number of recovered capsules with overgrowth as the percentage of the total number of recovered capsules for each individual animal.…”

Section: Microscopymentioning

confidence: 99%

Chemistry and biocompatibility of alginate‐PLL capsules for immunoprotection of mammalian cells

Vos

Hoogmoed

Busscher

2002

J. Biomed. Mater. Res.

104

106

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Transplantation of encapsulated living cells is a promising approach for the treatment of a wide variety of diseases. Large-scale application of the technique, however, is hampered by insufficient biocompatibility of the capsules. In order to get means to study factors influencing the biocompatibility of capsule for encapsulation of living cells, we have correlated the chemical composition of the surface of commonly applied alginate-PLL capsules with the biological response in rats. Capsules prepared of alginates with an intermediate guluronic (G) acid content proved to be biocompatible, whereas capsules prepared of high-G alginates were overgrown by inflammatory cells. We applied X-ray photoelectron spectroscopy to correlate the biological responses with the chemical compositions of the capsule surfaces. High-G alginate capsules proved to have a higher PLL content but less surface binding sites for PLL than low-G alginates. This study, shows for the first time that biological responses against capsules can be successfully correlated to its chemical characteristics.

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“…29 Sections were prepared at 2 m and stained with RomanovskyGiemsa stain and applied for detecting imperfections in the capsule membrane and for quantifying the composition of the overgrowth and determining the number of capsules with and without overgrowth. Different cell types in the overgrowth were assessed by identifying cells in the capsular overgrowth with the morphological characteristics of monocytes/macrophages, lymphocytes, granulocytes, fibroblasts, basophiles, erythrocytes, and multinucleated giant cells.…”

Section: Microscopymentioning

confidence: 99%

Tissue responses against immunoisolating alginate‐PLL capsules in the immediate posttransplant period

Vos

Hoogmoed

Haan

et al. 2002

J. Biomed. Mater. Res.

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Alginate-polylysine (PLL) capsules are commonly applied for immunoisolation of living cells for the treatment of a wide variety of diseases. Large-scale application of the technique, however, is hampered by insufficient biocompatibility of the capsules with failure of the grafts as a consequence. Most studies addressing biocompatibility issues of alginate-PLL capsules have focused on the degree of overgrowth on the capsules after graft failure and not on the reaction against the capsules in the immediate posttransplant period. Therefore, capsules were implanted in the peritoneal cavity of rats and retrieved 1, 5, and 7 days later for histological examination and X-ray photoelectron spectroscopy analysis for evaluation of chemical changes at the capsule surface. After implantation, the nitrogen signal increased from 5% on day 0, to 8.6% on day 7, illustrating protein adsorption on the capsule's surface. This increase in protein content of the membrane was accompanied by an increase in the percentage of overgrown capsules from 0.5 +/- 0.3% on day 1 to 3.3 +/- 1.6% on day 7. The cellular overgrowth was composed of monocytes/macrophages, granulocytes, fibroblasts, erythrocytes, multinucleated giant cells, and basophils. This overgrowth was not statical as generally assumed but rather dynamic as illustrated by our observation that at day 1 after implantation we mainly found monocytes/macrophages and granulocytes that on later time points were substituted by fibroblasts. As the inflammatory reaction predictably interfere with survival of encapsulated cells, efforts should be made to suppress activities or recruitment of inflammatory cells. These efforts may be temporary rather than permanent because most inflammatory cells have disappeared after 2 weeks of implantation.

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Glycol Methacrylate Embedding of Algmate-Polylysine Microencapsulated Pancreatic Islets

Cited by 17 publications

References 13 publications

Long-term biocompatibility, chemistry, and function of microencapsulated pancreatic islets

Long-term biocompatibility, chemistry, and function of microencapsulated pancreatic islets

Chemistry and biocompatibility of alginate‐PLL capsules for immunoprotection of mammalian cells

Tissue responses against immunoisolating alginate‐PLL capsules in the immediate posttransplant period

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