Elastin-Collagen Based Hydrogels as Model Scaffolds to Induce Three-Dimensional Adipocyte Culture from Adipose Derived Stem Cells

Abstract

This study aimed to probe the effect of formulation of scaffolds prepared using collagen and elastin-like polypeptide (ELP) and their resulting physico-chemical and mechanical properties on the adipogenic differentiation of human adipose derived stem cells (hASCs). Six different ELP-collagen scaffolds were prepared by varying the collagen concentration (2 and 6 mg/mL), ELP addition (6 mg/mL), or crosslinking of the scaffolds. FTIR spectroscopy indicated secondary bonding interactions between collagen and ELP, while scanning electron microscopy revealed a porous structure for all scaffolds. Increased collagen concentration, ELP addition, and presence of crosslinking decreased swelling ratio and increased elastic modulus and compressive strength of the scaffolds. The scaffold characteristics influenced cell morphology, wherein the hASCs seeded in the softer, non-crosslinked scaffolds displayed a spread morphology. We determined that stiffer and/or crosslinked elastin-collagen based scaffolds constricted the spreading of hASCs, leading to a spheroid morphology and yielded an enhanced adipogenic differentiation as indicated by Oil Red O staining. Overall, this study underscored the importance of spheroid morphology in adipogenic differentiation, which will allow researchers to create more physiologically-relevant three-dimensional, in vitro culture models.

Human Adipose-Derived Stromal/Stem Cell Culture and Analysis Methods for Adipose Tissue Modeling In Vitro: A Systematic Review

“…hASC attachment and adipocyte maturation have been shown to impact scaffold structure [10,16]. Additionally, scaffold material and properties have been shown to impact hASC adipogenesis [16]. Notable articles identified in this review characterized cell-scaffold interactions throughout hASC attachment, proliferation, and differentiation.…”

“…Finally, none of the screened articles exclusively studied 2D culture; therefore, all articles included in this analysis report 3D culture methods. Data and analysis hereafter exclusively refer to the 27 articles [4,5,[8][9][10][11][12][13][15][16][17][19][20][21][22][23][24][25][26]28,30,31,33,38,44,45,48] identified to be most relevant to the central goal of this systematic review. Out of the 27 relevant articles, 26 articles used adipogenic medium to differentiate hASC into adipocytes in vitro.…”

“…Oil red O (ORO) is a staining solution that accumulates in cellular compartments that are lipid rich; therefore, it can be used to detect the neutral lipid amounts after hASC adipogenesis. ORO can be observed using bright field and fluorescent microscopy [16]. Of articles included in this review, 51.9% used ORO staining to qualitatively observe neutral lipid content; however, only one article included in this review (3.7%) used ORO staining to quantitatively measure adipogenesis by eluting the remaining stain with isopropanol and measuring the absorbance of the solution [129].…”

“…Only one article (5%) used an entirely synthetic scaffold, while the remaining articles incorporated biologically derived materials. Gelatin was identified as one of the most commonly used scaffold materials as it naturally contains RGD peptides found in many ECM components that promote cell adhesion [13,16,17,21]. Collagen is another commonly used scaffold material as it is the most abundant protein in human adipose tissue ECM and, therefore, closely recapitulates the native tissue environment [10,31].…”

“…Collagen is another commonly used scaffold material as it is the most abundant protein in human adipose tissue ECM and, therefore, closely recapitulates the native tissue environment [10,31]. hASC attachment and adipocyte maturation have been shown to impact scaffold structure [10,16]. Additionally, scaffold material and properties have been shown to impact hASC adipogenesis [16].…”