Subcutaneous Construction of Engineered Adipose Tissue with Fat Lobule-Like Structure Using Injectable Poly-Benzyl-L-Glutamate Microspheres Loaded with Adipose-Derived Stem Cells.

Wentao Sun,Qi Yong,Lei Cui,Jianjun Fang,Jingbo Yin,Sufang Li,Qingping Xie

doi:10.1371/journal.pone.0135611

Wentao Sun, Qi Yong + Show 5 more

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https://doi.org/10.1371/journal.pone.0135611

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Abstract

Porous microcarriers were fabricated from synthesized poly(γ-benzyl-L-glutamate) (PBLG) polymer to engineer adipose tissue with lobule-like structure via the injectable approach. The adipogenic differentiation of human adipose-derived stem cells (hASCs) seeded on porous PBLG microcarriers was determined by adipogenic gene expression and glycerol-3-phosphate dehydrogenase enzyme activity. In vitro adipogenic cultivation was performed for 7 days, and induced hASC/PBLG complex (Adi-ASC/PBLG group) was subcutaneously injected into nude mice. Injections of PBLG microcarriers alone (PBLG group) and non-induced hASC/PBLG complex (ASC/PBLG group) served as controls. Newly formed tissues were harvested after 4 and 8 weeks. Generation of subcutaneous adipose tissue with typical lobule-like structure separated by fibrous septa was observed upon injection of adipogenic-induced hASC/microsphere complex. Adipogenesis significantly increased in the Adi-ASC/PBLG group compared with the control groups. The angiogenesis in the engineered adipose tissue was comparable to that in normal tissue as determined by capillary density and luminal diameter. Cell tracking assay demonstrated that labeled hASCs remained detectable in the neo-generated tissues 8 weeks post-injection using green fluorescence protein-labeled hASCs. These results indicate that adipose tissue with typical lobule-like structure could be engineered using injectable porous PBLG microspheres loaded with adipogenic-induced hASCs.

Highlights

Engineering adipose tissue is a promising alternative to plastic and reconstructive surgery for restoring body contours in patients who lost contour because of surgical resections, trauma, or congenital abnormalities [1, 2]
This study evaluated the adipogenic differentiation of the Adipose-derived stem cells (ASCs) seeded on PBLG microcarriers in vitro and engineered adipose tissue by injecting human adipose-derived stem cells (hASCs)-loaded PBLG microcarriers in vivo
This study demonstrates that the novel porous PBLG microspheres possess good biocompatibility for proliferation of seeded hASCs

Summary

Introduction

Engineering adipose tissue is a promising alternative to plastic and reconstructive surgery for restoring body contours in patients who lost contour because of surgical resections, trauma, or congenital abnormalities [1, 2]. Adipose-derived stem cells (ASCs) are a readily and ideal cell source for adipose tissue engineering among the candidate seed cells because of their sufficient availability, minimally invasive procurement, high proliferation and adipogenic differentiation potential [4]. The ASC yield after expansion is relatively high and averages approximately 2 × 106 cells per ml of lipoaspirate tissue [2]. Degradable scaffold is another important element in cell-based tissue engineering. Polypeptide-derived copolymers have drawn considerable attention as surgical sutures, drug delivery vehicles, and scaffolds in tissue engineering because of their adjustable biodegradability, low immunogenicity, good biocompatibility, and excellent mechanical properties [6,7,8]. Synthetic poly(γ-benzyl-L-glutamate) (PBLG), whose polymer backbone has a degradable amide bond, exhibits great fabrication potential in various copolymers, such as polypeptides, because of its excellent solubility in various chemical moieties and most organic solvents [8]

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