title: Strategy for constructing vascularized adipose units in poly(l-glutamic acid) hydrogel porous scaffold through inducing in-situ formation of ASCs spheroids.
abstract: Vascularization is of great importance to adipose tissue regeneration. Here we introduced a paradigm that using scaffold to induce ASC spheroids, so to promote vascularized adipose tissue regeneration. Poly (l-glutamic acid) (PLGA) was activated by EDC, followed by being cross-linked by Adipic dihydrazide (ADH) to form a homogeneous hydrogel. Lyophilization was then carried out to create porous structure. The PLGA hydrogel scaffold possessed a significant swollen hydrophilic network to weaken cell-scaffold adhesion but drive ASCs to aggregate to form spheroids. Increase of seeding cell density was proved to result in the increase of spheroid size, upregulating angiogenic genes (VEGF and FGF-2) expression by enhancing the hypoxia-induced paracrine secretion. Also, the adipogenic differentiation of ASCs was achieved in spheroids in vitro. Moreover, the in vivo vascularized adipose tissue regeneration was evaluated in the dorsum of nude mice. After 12weeks post-implantation, the significant angiogenesis was found in both adipogenic induced and non-induced engineered tissue. In adipogenic induced group, the clear ring-like morphology, the large vacuole in the middle of the cell and the Oil red O staining demonstrated adipose tissue formation.
  
  
  
  Vascularization is of great importance to adipose tissue regeneration. Adipose derived stem cell (ASC) spheroids possessed not only the high efficiency of vascularization, but also the improved differentiation ability. Several research works have illustrated the advantage of ASC spheroids in vascularization. However, in adipose regeneration, ASC spheroid was rarely used. Even so, it is reasonable to believe that ASC spheroids hold a great promise in vascularized adipose tissue engineering. Thus in the present study, we introduced a method to create lots of ASC spheroids that acted as lots of individual adipogenesis and angiogenesis units inside of a porous hydrogel scaffold. Then, the scaffold carrying ASC spheroids was implanted subcutaneously in nude mice to preliminarily evaluate the adipose tissue generation and blood vessel formation.
authors.affiliation: Department of Polymer Materials, Shanghai University, 99 Shangda Road, Shanghai 200444, PR China.
authors.forename: Kunxi
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Department of Polymer Materials, Shanghai University, 99 Shangda Road, Shanghai 200444, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Song
authors.affiliation: Department of Polymer Materials, Shanghai University, 99 Shangda Road, Shanghai 200444, PR China.
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Polymer Materials, Shanghai University, 99 Shangda Road, Shanghai 200444, PR China.
authors.forename: Shifeng
authors.initials: S
authors.lastname: Yan
authors.affiliation: Department of Polymer Materials, Shanghai University, 99 Shangda Road, Shanghai 200444, PR China.
authors.forename: Guifei
authors.initials: G
authors.lastname: Li
authors.affiliation: Medical Science & Research Center, Beijing Shijitan Hospital, Capital Medical University, 10 Tieyi Road, Beijing 100038, PR China. Electronic address: cuileite@aliyun.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Cui
authors.affiliation: Department of Polymer Materials, Shanghai University, 99 Shangda Road, Shanghai 200444, PR China. Electronic address: jbyin@shu.edu.cn.
authors.forename: Jingbo
authors.initials: J
authors.lastname: Yin
mesh_terms: D050156:Adipogenesis / Q000187:drug effects; D000273:Adipose Tissue / Q000098:blood supply* / Q000166:cytology*; D000328:Adult; D043925:Angiogenesis Inducing Agents / Q000378:metabolism; D048429:Cell Size / Q000187:drug effects; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000138:chemical synthesis / Q000737:chemistry; D019344:Lactic Acid / Q000138:chemical synthesis / Q000737:chemistry; D008422:Materials Testing; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D011099:Polyglutamic Acid / Q000494:pharmacology*; D011100:Polyglycolic Acid / Q000138:chemical synthesis / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D016062:Porosity; D018874:Spheroids, Cellular / Q000166:cytology* / Q000648:ultrastructure; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000648:ultrastructure; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D043925:Angiogenesis Inducing Agents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011099:Polyglutamic Acid; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D011100:Polyglycolic Acid; D019344:Lactic Acid
keywords: Adipose derived stem cells; Adipose tissue engineering; Cellular spheroid; Poly(l-glutamic acid); Vascularization