Post-loading of proangiogenic growth factors in PLGA microspheres

Karina C Scheiner; Roel F Maas-Bakker; Mies J van Steenbergen; Steven P Schwendeman; Wim E Hennink; Robbert J Kok

doi:10.1016/j.ejpb.2020.10.022

Post-loading of proangiogenic growth factors in PLGA microspheres

Karina C Scheiner
, Roel F Maas-Bakker
, Mies J van Steenbergen
, Steven P Schwendeman
, Wim E Hennink
, Robbert J Kok

Department of Pharmaceutical Sciences and the Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA.

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

Active self-encapsulation (ASE) is a recently developed post-loading method based on absorption of (positively charged) proteins in microporous PLGA microspheres loaded with negatively charged polysaccharides (trapping agents). The aim of this study was to investigate ASE for simultaneous loading and controlled release of multiple growth factors. For this purpose, vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and insulin-like growth factor (IGF) were loaded in microspheres containing high molecular weight dextran sulfate (HDS) as trapping agent; loading was performed in a concentrated growth factor solution of low ionic strength and of pH 5 under conditions at which the proteins are positively charged. Subsequent pore closure was induced by incubation of the growth factor-loaded microspheres at 42.5 °C, i.e. above the Tg of (hydrated) PLGA (~30 °C). A 1:1:1 combination of VEGF, FGF and IGF was loaded with high loading (4.3%) and loading efficiency (91%). The in vitro release kinetics and bioactivity of loaded growth factors were studied for 4 weeks using ELISA and an endothelial cell proliferation assay, respectively. While IGF was released quickly, VEGF and FGF were continuously released for 4 weeks in their bioactive form, whereby a growth factor combination had a synergistic angiogenic effect. Therefore, ASE is a suitable method for co-loading growth factors which can provide sustained release profiles of bioactive growth factors, which is attractive for vascularization of biomaterial implants.

Original language	English
Pages (from-to)	1-10
Number of pages	10
Journal	European Journal of Pharmaceutics and Biopharmaceutics
Volume	158
DOIs	https://doi.org/10.1016/j.ejpb.2020.10.022
Publication status	Published - Jan 2021

Bibliographical note

Funding Information:
This research was supported by European Union’s Horizon 2020 research and innovation program [grant agreement number 645991 (DRIVE)]. Karina Scheiner acknowledges a personal travel grant from the Foundation “De Drie Lichten”. The authors thank Linda Barthel (Microscope and Image Analysis Laboratory, University of Michigan, USA) for her excellent assistance with confocal fluorescence microscopy. Rae Sung Chang, Karl Olsen, Rose Ackermann (Department of Pharmaceutical Sciences and the Biointerfaces Institute, University of Michigan), Louis van Bloois, Sjaak Jong (Department of Pharmaceutics, Utrecht University, the Netherlands) and Gert Hendriks (InnoCore Pharmaceuticals BV, Groningen, the Netherlands) are greatly acknowledged for their contribution to this work.

Funding Information:
This research was supported by European Union's Horizon 2020 research and innovation program [grant agreement number 645991 (DRIVE)]. Karina Scheiner acknowledges a personal travel grant from the Foundation ?De Drie Lichten?. The authors thank Linda Barthel (Microscope and Image Analysis Laboratory, University of Michigan, USA) for her excellent assistance with confocal fluorescence microscopy. Rae Sung Chang, Karl Olsen, Rose Ackermann (Department of Pharmaceutical Sciences and the Biointerfaces Institute, University of Michigan), Louis van Bloois, Sjaak Jong (Department of Pharmaceutics, Utrecht University, the Netherlands) and Gert Hendriks (InnoCore Pharmaceuticals BV, Groningen, the Netherlands) are greatly acknowledged for their contribution to this work.

Publisher Copyright:
© 2020 The Authors

Keywords

Controlled release
Growth factors
Implants
PLGA
Post-loading
Therapeutic angiogenesis

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Cite this

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title = "Post-loading of proangiogenic growth factors in PLGA microspheres",

abstract = "Active self-encapsulation (ASE) is a recently developed post-loading method based on absorption of (positively charged) proteins in microporous PLGA microspheres loaded with negatively charged polysaccharides (trapping agents). The aim of this study was to investigate ASE for simultaneous loading and controlled release of multiple growth factors. For this purpose, vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and insulin-like growth factor (IGF) were loaded in microspheres containing high molecular weight dextran sulfate (HDS) as trapping agent; loading was performed in a concentrated growth factor solution of low ionic strength and of pH 5 under conditions at which the proteins are positively charged. Subsequent pore closure was induced by incubation of the growth factor-loaded microspheres at 42.5 °C, i.e. above the Tg of (hydrated) PLGA (\textasciitilde{}30 °C). A 1:1:1 combination of VEGF, FGF and IGF was loaded with high loading (4.3\%) and loading efficiency (91\%). The in vitro release kinetics and bioactivity of loaded growth factors were studied for 4 weeks using ELISA and an endothelial cell proliferation assay, respectively. While IGF was released quickly, VEGF and FGF were continuously released for 4 weeks in their bioactive form, whereby a growth factor combination had a synergistic angiogenic effect. Therefore, ASE is a suitable method for co-loading growth factors which can provide sustained release profiles of bioactive growth factors, which is attractive for vascularization of biomaterial implants.",

keywords = "Controlled release, Growth factors, Implants, PLGA, Post-loading, Therapeutic angiogenesis",

author = "Scheiner, \{Karina C\} and Maas-Bakker, \{Roel F\} and \{van Steenbergen\}, \{Mies J\} and Schwendeman, \{Steven P\} and Hennink, \{Wim E\} and Kok, \{Robbert J\}",

note = "Funding Information: This research was supported by European Union{\textquoteright}s Horizon 2020 research and innovation program [grant agreement number 645991 (DRIVE)]. Karina Scheiner acknowledges a personal travel grant from the Foundation “De Drie Lichten”. The authors thank Linda Barthel (Microscope and Image Analysis Laboratory, University of Michigan, USA) for her excellent assistance with confocal fluorescence microscopy. Rae Sung Chang, Karl Olsen, Rose Ackermann (Department of Pharmaceutical Sciences and the Biointerfaces Institute, University of Michigan), Louis van Bloois, Sjaak Jong (Department of Pharmaceutics, Utrecht University, the Netherlands) and Gert Hendriks (InnoCore Pharmaceuticals BV, Groningen, the Netherlands) are greatly acknowledged for their contribution to this work. Funding Information: This research was supported by European Union's Horizon 2020 research and innovation program [grant agreement number 645991 (DRIVE)]. Karina Scheiner acknowledges a personal travel grant from the Foundation ?De Drie Lichten?. The authors thank Linda Barthel (Microscope and Image Analysis Laboratory, University of Michigan, USA) for her excellent assistance with confocal fluorescence microscopy. Rae Sung Chang, Karl Olsen, Rose Ackermann (Department of Pharmaceutical Sciences and the Biointerfaces Institute, University of Michigan), Louis van Bloois, Sjaak Jong (Department of Pharmaceutics, Utrecht University, the Netherlands) and Gert Hendriks (InnoCore Pharmaceuticals BV, Groningen, the Netherlands) are greatly acknowledged for their contribution to this work. Publisher Copyright: {\textcopyright} 2020 The Authors",

year = "2021",

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doi = "10.1016/j.ejpb.2020.10.022",

language = "English",

volume = "158",

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T1 - Post-loading of proangiogenic growth factors in PLGA microspheres

AU - Scheiner, Karina C

AU - Maas-Bakker, Roel F

AU - van Steenbergen, Mies J

AU - Schwendeman, Steven P

AU - Hennink, Wim E

AU - Kok, Robbert J

N1 - Funding Information: This research was supported by European Union’s Horizon 2020 research and innovation program [grant agreement number 645991 (DRIVE)]. Karina Scheiner acknowledges a personal travel grant from the Foundation “De Drie Lichten”. The authors thank Linda Barthel (Microscope and Image Analysis Laboratory, University of Michigan, USA) for her excellent assistance with confocal fluorescence microscopy. Rae Sung Chang, Karl Olsen, Rose Ackermann (Department of Pharmaceutical Sciences and the Biointerfaces Institute, University of Michigan), Louis van Bloois, Sjaak Jong (Department of Pharmaceutics, Utrecht University, the Netherlands) and Gert Hendriks (InnoCore Pharmaceuticals BV, Groningen, the Netherlands) are greatly acknowledged for their contribution to this work. Funding Information: This research was supported by European Union's Horizon 2020 research and innovation program [grant agreement number 645991 (DRIVE)]. Karina Scheiner acknowledges a personal travel grant from the Foundation ?De Drie Lichten?. The authors thank Linda Barthel (Microscope and Image Analysis Laboratory, University of Michigan, USA) for her excellent assistance with confocal fluorescence microscopy. Rae Sung Chang, Karl Olsen, Rose Ackermann (Department of Pharmaceutical Sciences and the Biointerfaces Institute, University of Michigan), Louis van Bloois, Sjaak Jong (Department of Pharmaceutics, Utrecht University, the Netherlands) and Gert Hendriks (InnoCore Pharmaceuticals BV, Groningen, the Netherlands) are greatly acknowledged for their contribution to this work. Publisher Copyright: © 2020 The Authors

PY - 2021/1

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N2 - Active self-encapsulation (ASE) is a recently developed post-loading method based on absorption of (positively charged) proteins in microporous PLGA microspheres loaded with negatively charged polysaccharides (trapping agents). The aim of this study was to investigate ASE for simultaneous loading and controlled release of multiple growth factors. For this purpose, vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and insulin-like growth factor (IGF) were loaded in microspheres containing high molecular weight dextran sulfate (HDS) as trapping agent; loading was performed in a concentrated growth factor solution of low ionic strength and of pH 5 under conditions at which the proteins are positively charged. Subsequent pore closure was induced by incubation of the growth factor-loaded microspheres at 42.5 °C, i.e. above the Tg of (hydrated) PLGA (~30 °C). A 1:1:1 combination of VEGF, FGF and IGF was loaded with high loading (4.3%) and loading efficiency (91%). The in vitro release kinetics and bioactivity of loaded growth factors were studied for 4 weeks using ELISA and an endothelial cell proliferation assay, respectively. While IGF was released quickly, VEGF and FGF were continuously released for 4 weeks in their bioactive form, whereby a growth factor combination had a synergistic angiogenic effect. Therefore, ASE is a suitable method for co-loading growth factors which can provide sustained release profiles of bioactive growth factors, which is attractive for vascularization of biomaterial implants.

AB - Active self-encapsulation (ASE) is a recently developed post-loading method based on absorption of (positively charged) proteins in microporous PLGA microspheres loaded with negatively charged polysaccharides (trapping agents). The aim of this study was to investigate ASE for simultaneous loading and controlled release of multiple growth factors. For this purpose, vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and insulin-like growth factor (IGF) were loaded in microspheres containing high molecular weight dextran sulfate (HDS) as trapping agent; loading was performed in a concentrated growth factor solution of low ionic strength and of pH 5 under conditions at which the proteins are positively charged. Subsequent pore closure was induced by incubation of the growth factor-loaded microspheres at 42.5 °C, i.e. above the Tg of (hydrated) PLGA (~30 °C). A 1:1:1 combination of VEGF, FGF and IGF was loaded with high loading (4.3%) and loading efficiency (91%). The in vitro release kinetics and bioactivity of loaded growth factors were studied for 4 weeks using ELISA and an endothelial cell proliferation assay, respectively. While IGF was released quickly, VEGF and FGF were continuously released for 4 weeks in their bioactive form, whereby a growth factor combination had a synergistic angiogenic effect. Therefore, ASE is a suitable method for co-loading growth factors which can provide sustained release profiles of bioactive growth factors, which is attractive for vascularization of biomaterial implants.

KW - Controlled release

KW - Growth factors

KW - Implants

KW - PLGA

KW - Post-loading

KW - Therapeutic angiogenesis

UR - https://www.scopus.com/pages/publications/85096165982

U2 - 10.1016/j.ejpb.2020.10.022

DO - 10.1016/j.ejpb.2020.10.022

M3 - Article

C2 - 33152482

SN - 0939-6411

VL - 158

SP - 1

EP - 10

JO - European Journal of Pharmaceutics and Biopharmaceutics

JF - European Journal of Pharmaceutics and Biopharmaceutics

ER -

Post-loading of proangiogenic growth factors in PLGA microspheres

Abstract

Bibliographical note

Keywords

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