In tissue engineering, a highly porous artificial extracellular matrix or scaffold is required to accommodate mammalian cells and guide their growth and tissue regeneration in three dimensions. However, existing three-dimensional scaffolds for tissue engineering proved less than ideal for actual applications, not only because they lack mechanical strength, but they also do not guarantee interconnected channels. In this paper, the authors analyze the factors necessary to enhance the design and manufacture of scaffolds for use in tissue engineering in terms of materials, structure, and mechanical properties and review the traditional scaffold fabrication methods. Advantages and limitations of these traditional methods are also discussed.
Tissue engineering (TE) is an important emerging area in biomedical engineering for creating biological alternatives for harvested tissues, implants, and prostheses. In TE, a highly porous artificial extracellular matrix or scaffold is required to accommodate mammalian cells and guide their growth and tissue regeneration in three-dimension (3D). However, existing 3D scaffolds for TE proved less than ideal for actual applications because they lack mechanical strength, interconnected channels, and controlled porosity or pores distribution. In this paper, the authors review the application and advancement of rapid prototyping (RP) techniques in the design and creation of synthetic scaffolds for use in TE. We also review the advantages and benefits, and limitations and shortcomings of current RP techniques as well as the future direction of RP development in TE scaffold fabrication.
The present study was carried out to investigate the lipid-lowering effect of luteolin by using a cell model of steatosis induced by palmitate. Incubation of HepG2 cells with palmitate markedly increased lipid accumulation (Oil Red O staining), the genes involved in lipogenesis, including fatty acid synthase (FAS) and its upstream regulator sterol regulatory element binding protein 1c (SREBP-1c), and reactive oxygen species (ROS) production. Luteolin enhanced the phosphorylation of AMP-activated protein kinase α (AMPKα) and its primary downstream targeting enzyme, acetyl-CoA carboxylase (ACC), up-regulated gene expression of carnitine palmitoyl transferase 1 (CPT-1), which is the rate-limiting enzyme in mitochondrial fatty acid β-oxidation, and down-regulated SREBP-1c and FAS mRNA levels in the absence and presence of palmitate. In addition, luteolin significantly decreased ROS production and ameliorated lipid accumulation in HepG2 cells caused by palmitate. Furthermore, intracellular triglyceride (TG) measurement indicated that the luteolin-mediated reduction of enhanced TG caused by palmitate was blocked by pretreatment with the AMPK inhibitor, compound C. The results suggested that the lipid-lowering effect of luteolin might be partially mediated by the up-regulation of CPT-1 and down-regulation of SREBP-1c and FAS gene expression, possibly by activation of the AMPK signaling pathway, and partially might be through its antioxidative actions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.