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Development and Characterization of a Collagen-Based Matrix for Vascularization and Cell Delivery.

Ellis CE, Ellis LK, Korbutt RS, Suuronen EJ, Korbutt GS - Biores Open Access (2015)

Bottom Line: The swelling ratio was found to be significantly negatively correlated with increasing cross-linker concentrations (p<0.0001; R2=0.718).CD31 staining visualized the capillaries at each time point.Taken together, these data show that this collagen-based matrix is reproducible with cross-linking-dependent properties that can be optimized to support vascularization and islet function.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, University of Alberta , Edmonton, Canada . ; Alberta Diabetes Institute, University of Alberta , Edmonton, Canada .

ABSTRACT
Since the development of the Edmonton protocol, islet transplantation is increasingly encouraging as a treatment for type 1 diabetes. Strategies to ameliorate problems with the intraportal site include macroencapsulating the islets in diverse biomaterials. Characterization of these biomaterials is important to optimally tune the properties to support islets and promote vascularization. In this study, we characterize the cross-linker-dependent properties of collagen-based matrices containing chondroitin-6-sulfate, chitosan, and laminin, cross-linked with 7.5, 30, or 120 mM of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide. The swelling ratio was found to be significantly negatively correlated with increasing cross-linker concentrations (p<0.0001; R2=0.718). The matrix released insulin in a reproducible logarithmic manner (R2 of 0.99 for all concentrations), demonstrating cross-linker-dependent control of drug release. The matrices with the highest cross-linker concentrations resisted degradation by collagenase for longer than the lowest concentrations (58.13%±2.22% vs. 13.69%±7.67%; p<0.05). Scanning electron microscopy images of the matrices revealed that the matrices had uniform topography and porosity, indicating efficient cross-linking and incorporation of the polymer components. Matrices were transplanted subcutaneously in naive BALB/c mice, and the number and size of vessels were quantified using von Willebrand factor staining; matrices with higher cross-linking concentrations had significantly larger capillaries at every time point up to 4 weeks after transplantation compared to the lowest cross-linker concentration group. CD31 staining visualized the capillaries at each time point. Taken together, these data show that this collagen-based matrix is reproducible with cross-linking-dependent properties that can be optimized to support vascularization and islet function.

No MeSH data available.


Related in: MedlinePlus

NPIs embedded in matrices with 7.5 mM (B), 30 mM (C), and 120 mM (D) cross-linker concentrations and in standard Ham's F10 culture media as a control (A) cultured for 7 days, then fixed and paraffin-embedded; sections were stained for TUNEL and compared to TUNEL-positive controls (E). Scale bars of (A–E) are 20 μm and scale bars of high magnification insets are 10 μm.
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Related In: Results  -  Collection


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f5: NPIs embedded in matrices with 7.5 mM (B), 30 mM (C), and 120 mM (D) cross-linker concentrations and in standard Ham's F10 culture media as a control (A) cultured for 7 days, then fixed and paraffin-embedded; sections were stained for TUNEL and compared to TUNEL-positive controls (E). Scale bars of (A–E) are 20 μm and scale bars of high magnification insets are 10 μm.

Mentions: No TUNEL-positive cells were visible in any of the matrices (Fig. 5), indicating excellent support for the NPIs. The control NPIs cultured in the standard Ham's F10 media (Fig. 5A) had the most apoptotic cells as one or two cells per section were TUNEL positive.


Development and Characterization of a Collagen-Based Matrix for Vascularization and Cell Delivery.

Ellis CE, Ellis LK, Korbutt RS, Suuronen EJ, Korbutt GS - Biores Open Access (2015)

NPIs embedded in matrices with 7.5 mM (B), 30 mM (C), and 120 mM (D) cross-linker concentrations and in standard Ham's F10 culture media as a control (A) cultured for 7 days, then fixed and paraffin-embedded; sections were stained for TUNEL and compared to TUNEL-positive controls (E). Scale bars of (A–E) are 20 μm and scale bars of high magnification insets are 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4497631&req=5

f5: NPIs embedded in matrices with 7.5 mM (B), 30 mM (C), and 120 mM (D) cross-linker concentrations and in standard Ham's F10 culture media as a control (A) cultured for 7 days, then fixed and paraffin-embedded; sections were stained for TUNEL and compared to TUNEL-positive controls (E). Scale bars of (A–E) are 20 μm and scale bars of high magnification insets are 10 μm.
Mentions: No TUNEL-positive cells were visible in any of the matrices (Fig. 5), indicating excellent support for the NPIs. The control NPIs cultured in the standard Ham's F10 media (Fig. 5A) had the most apoptotic cells as one or two cells per section were TUNEL positive.

Bottom Line: The swelling ratio was found to be significantly negatively correlated with increasing cross-linker concentrations (p<0.0001; R2=0.718).CD31 staining visualized the capillaries at each time point.Taken together, these data show that this collagen-based matrix is reproducible with cross-linking-dependent properties that can be optimized to support vascularization and islet function.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, University of Alberta , Edmonton, Canada . ; Alberta Diabetes Institute, University of Alberta , Edmonton, Canada .

ABSTRACT
Since the development of the Edmonton protocol, islet transplantation is increasingly encouraging as a treatment for type 1 diabetes. Strategies to ameliorate problems with the intraportal site include macroencapsulating the islets in diverse biomaterials. Characterization of these biomaterials is important to optimally tune the properties to support islets and promote vascularization. In this study, we characterize the cross-linker-dependent properties of collagen-based matrices containing chondroitin-6-sulfate, chitosan, and laminin, cross-linked with 7.5, 30, or 120 mM of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide. The swelling ratio was found to be significantly negatively correlated with increasing cross-linker concentrations (p<0.0001; R2=0.718). The matrix released insulin in a reproducible logarithmic manner (R2 of 0.99 for all concentrations), demonstrating cross-linker-dependent control of drug release. The matrices with the highest cross-linker concentrations resisted degradation by collagenase for longer than the lowest concentrations (58.13%±2.22% vs. 13.69%±7.67%; p<0.05). Scanning electron microscopy images of the matrices revealed that the matrices had uniform topography and porosity, indicating efficient cross-linking and incorporation of the polymer components. Matrices were transplanted subcutaneously in naive BALB/c mice, and the number and size of vessels were quantified using von Willebrand factor staining; matrices with higher cross-linking concentrations had significantly larger capillaries at every time point up to 4 weeks after transplantation compared to the lowest cross-linker concentration group. CD31 staining visualized the capillaries at each time point. Taken together, these data show that this collagen-based matrix is reproducible with cross-linking-dependent properties that can be optimized to support vascularization and islet function.

No MeSH data available.


Related in: MedlinePlus