Artificial Organs | Pancreas

Sambanis, Athanassios

doi:10.1016/b978-0-08-088504-9.00418-9

Cited by 3 publications

(4 citation statements)

References 116 publications

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“…However, this methodology introduces additional obstacles to successful implementation on a clinical scale. Several different cell sources are currently being investigated for application in a BAP, including, but not limited to, autologous genetically engineered cells, autologous/allogeneic differentiated stem cells, and allo‐ or xenogeneic islets (Efrat, 2008; O'Sullivan et al, 2011; Sambanis, 2011). For allogeneic and autologous cell sources, over‐expression of pro‐survival molecules by insertion of a transgene may disrupt normal function, induce oncogenicity, and result in large batch‐to‐batch variability, prompting concerns about safety and efficacy.…”

Section: Discussionmentioning

confidence: 99%

Dual factor delivery of CXCL12 and Exendin‐4 for improved survival and function of encapsulated beta cells under hypoxic conditions

Duncanson

Sambanis

2013

Biotech & Bioengineering

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A bioartifical pancreas (BAP) remains a promising approach for treating insulin-dependent diabetes. Several obstacles to the clinical implementation of a BAP remain, including hypoxia following implantation. Within native pancreatic islets, CXCL12 and glucagon-like peptide-1 (GLP-1) act in a paracrine fashion to promote the survival, function, and proliferation of β-cells. This work sought to investigate if the presentation of CXCL12 and delivery of a GLP-1 receptor analog, Exendin-4 (Ex-4), alone and in combination, conferred pro-survival and insulinotropic effects on an encapsulated β-cell line, βTC-tet, cultured under hypoxic conditions of 7.6 mmHg O2 . Our findings indicate that presentation of CXCL12 in the encapsulation matrix completely abrogated apoptosis under hypoxic conditions. Delivery of Ex-4 increased insulin secretion rate under both normoxic and hypoxic conditions, and additionally reduced apoptosis under hypoxic conditions. Furthermore, presentation of CXCL12 combined with Ex-4 delivery significantly increased insulin secretion rate under hypoxic conditions compared to delivery of Ex-4 alone. These findings demonstrate that the presentation of CXCL12 combined with the delivery of Ex-4 may constitute a promising strategy for supporting β-cell function and survival following transplantation.

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Section: Discussionmentioning

confidence: 99%

Dual factor delivery of CXCL12 and Exendin‐4 for improved survival and function of encapsulated beta cells under hypoxic conditions

Duncanson

Sambanis

2013

Biotech & Bioengineering

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“…transplantation in mice (Surzyn et al ., ). The encapsulation methods mentioned, however, were fixed systems that retained the cells at the graft site, which are generally less advantageous in sustaining therapeutic cell numbers compared to the microcapsules employed in this study (Sambanis, ). Additionally, these studies attributed an increase or attenuation in BLI signal to cell growth or death without confirming this correlation in vitro and in explant studies, as was done in the present study.…”

Section: Discussionmentioning

confidence: 97%

“…As the field progressed into using tissue‐engineered microencapsulation strategies, BLI incorporation did not follow. Some studies have applied BLI to macrocapsule or fixed systems that retained the cells at a particular anatomical locale (Cheng et al ., ; Lee et al ., ; Surzyn et al ., ; Tarantal et al ., ), but these strategies lack certain advantages of freely floating microcapsules (Sambanis, ) and may not be optimal for cell function. It remains unknown whether free microcapsules, a routine transplant configuration for insulin therapy (Cui et al ., ; Goh et al ., ; Hoesli et al ., ; Landázuri et al ., ; Ngoc et al ., ; O'Shea et al ., ; Shao et al ., ), can indeed be successfully monitored in vivo using BLI.…”

Section: Introductionmentioning

confidence: 97%

“…Cell‐based therapies are currently under development for various diseases, as they offer significant promise to provide improved regulation of daily, vital body functions by restoring homeostasis better than a single drug. Microencapsulating the therapeutic cells within a biomaterial to provide partial immune protection has become a common tissue‐engineering approach to improving cell survival in vivo (Giraldo et al ., ; Sambanis, ). Although this approach is beneficial, there are still challenges to be faced by the transplantation research community in developing these grafts for long‐term restorative function.…”

Section: Introductionmentioning

confidence: 99%

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Bioluminescence tracking of alginate micro-encapsulated cell transplants

Tiernan

Sambanis

2014

J Tissue Eng Regen Med

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Cell-based therapies to treat loss-of-function hormonal disorders such as diabetes and Parkinson's disease are routinely coupled with encapsulation strategies, but an understanding of when and why grafts fail in vivo is lacking. Consequently, investigators cannot clearly define the key factors that influence graft success. Although bioluminescence is a popular method to track the survival of free cells transplanted in preclinical models, little is known of the ability to use bioluminescence for real-time tracking of microencapsulated cells. Furthermore, the impact that dynamic imaging distances may have, due to freely-floating microcapsules in vivo, on cell survival monitoring is unknown. This work addresses these questions by applying bioluminescence to a pancreatic substitute based on microencapsulated cells. Recombinant insulin-secreting cells were transduced with a luciferase lentivirus and microencapsulated in Ba crosslinked alginate for in vitro and in vivo studies. In vitro quantitative bioluminescence monitoring was possible and viable microencapsulated cells were followed in real time under both normoxic and anoxic conditions. Although in vivo dispersion of freely-floating microcapsules in the peritoneal cavity limited the analysis to a qualitative bioluminescence evaluation, signals consistently four orders of magnitude above background were clear indicators of temporal cell survival. Strong agreement between in vivo and in vitro cell proliferation over time was discovered by making direct bioluminescence comparisons between explanted microcapsules and parallel in vitro cultures. Broader application of this bioluminescence approach to retrievable transplants, in supplement to currently used end-point physiological tests, could improve understanding and accelerate development of cell-based therapies for critical clinical applications. Copyright © 2014 John Wiley & Sons, Ltd.

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Technological advancements in glucose monitoring and artificial pancreas systems for shaping diabetes care

Ghosh,

Verma

2024

Current Medical Research and Opinion

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Artificial Organs | Pancreas

Cited by 3 publications

References 116 publications

Dual factor delivery of CXCL12 and Exendin‐4 for improved survival and function of encapsulated beta cells under hypoxic conditions

Dual factor delivery of CXCL12 and Exendin‐4 for improved survival and function of encapsulated beta cells under hypoxic conditions

Bioluminescence tracking of alginate micro-encapsulated cell transplants

Technological advancements in glucose monitoring and artificial pancreas systems for shaping diabetes care

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