Ex vivo engineering of blood and lymphatic microvascular networks

Constructing 3D In Vitro Models of Heterocellular Solid Tumors and Stromal Tissues Using Extrusion-Based Bioprinting

Malignant tumor tissues exhibit inter- and intratumoral heterogeneities, aberrant development, dynamic stromal composition, diverse tissue phenotypes, and cell populations growing within localized mechanical stresses in hypoxic conditions. Experimental tumor models employing engineered systems that isolate and study these complex variables using in vitro techniques are under development as complementary methods to preclinical in vivo models. Here, advances in extrusion bioprinting as an enabling technology to recreate the three-dimensional tumor milieu and its complex heterogeneous characteristics are reviewed. Extrusion bioprinting allows for the deposition of multiple materials, or selected cell types and concentrations, into models based upon physiological features of the tumor. This affords the creation of complex samples with representative extracellular or stromal compositions that replicate the biology of patient tissue. Biomaterial engineering of printable materials that replicate specific features of the tumor microenvironment offer experimental reproducibility, throughput, and physiological relevance compared to animal models. In this review, we describe the potential of extrusion-based bioprinting to recreate the tumor microenvironment within in vitro models.

EGR1 Enhances Lymphangiogenesis via SOX18-Mediated Activation of JAK2/STAT3 Pathway

Background. Lymphangiogenesis is a process involved in the pathogenesis of many diseases. Identifying key molecules and pathway targeting this process is critical for lymphatic regeneration-associated disorders. EGR1 is a transcription factor, but its function in lymphangiogenesis is not yet known. This study is aimed at exploring the functional activity and molecular mechanism of EGR1 implicated in lymphangiogenesis. Methods. The CCK-8 method, transwell migration assay, and tube formation assay were used to detect the cell viability, motility, and tube formation of HDLEC cells, respectively. The luciferase reporter assay was applied to detect the impact of EGR1 on SOX18 promoter activity. CHIP assay was used to analyze the direct binding of EGR1 to the SOX18 promoter. qRT-PCR and Western blot analysis were performed to investigate molecules and pathway involved in lymphangiogenesis. Results. The EGR1 ectopic expression markedly increased the cell growth, mobility, tube formation, and the expression of lymphangiogenesis-associated markers (LYVE-1 and PROX1) in HDLEC cells. EGR1 interacted with the SXO18 gene promoter and transcriptionally regulated the SXO18 expression in HDLEC cells. Silencing of SOX18 abrogated the promotional activities of EGR1 on the cell viability, mobility, tube formation, and LYVE-1/PROX1 expression in HDLEC cells. SOX18 overexpression activated JAK/STAT signaling, which resulted in an increase in lymphangiogenesis in HDLEC cells. Conclusions. ERG1 can promote lymphangiogenesis, which is mediated by activating the SOX18/JAK/STAT3 cascade. ERG1 may serve as a promising target for the therapy of lymphatic vessel-related disorders.

Rationally design of electrospun polysaccharides polymeric nanofiber webs by various tools for biomedical applications: A review

Nanofibers have a particular benefit when delivering a spectrum of therapeutic drugs for diverse biomedical applications. Nanofibers are easily fabricated from cellulose acetate, chitosan, polycaprolactone, and other polymers with regulated morphology and release profiles due to nanotechnology's recent advancement. This review will provide the latest approaches to the fabrication of electrospun nanofibers containing herbal extracts, antimicrobial peptides, and antibiotics for wound-healing potential. Besides, synthesis and evaluation of nanofibrous mats, including conducting polymer and evaluate their possibility for wound healing. In addition, nanofibers are loaded with some drugs for skin cancer treatment and contain growth factors for tissue regeneration. Also, the current two-dimensional nanofibers limitations and the various techniques for convert two-dimensional to three-dimension nanofibers to avoid these drawbacks. Moreover, the future direction in improving the three-dimensional structure and functionality has been including.

Characterization of Tissue Engineered Endothelial Cell Networks in Composite Collagen-Agarose Hydrogels

Scaffolds constitute an important element in vascularized tissues and are therefore investigated for providing the desired mechanical stability and enabling vasculogenesis and angiogenesis. In this study, supplementation of hydrogels containing either Matrigel^TM and rat tail collagen I (Matrigel^TM/rCOL) or human collagen (hCOL) with SeaPlaque^TM agarose were analyzed with regard to construct thickness and formation and characteristics of endothelial cell (EC) networks compared to constructs without agarose. Additionally, the effect of increased rCOL content in Matrigel^TM/rCOL constructs was studied. An increase of rCOL content from 1 mg/mL to 3 mg/mL resulted in an increase of construct thickness by approximately 160%. The high rCOL content, however, impaired the formation of an EC network. The supplementation of Matrigel^TM/rCOL with agarose increased the thickness of the hydrogel construct by approximately 100% while supporting the formation of a stable EC network. The use of hCOL/agarose composite hydrogels led to a slight increase in the thickness of the 3D hydrogel construct and supported the formation of a multi-layered EC network compared to control constructs. Our findings suggest that agarose/collagen-based composite hydrogels are promising candidates for tissue engineering of vascularized constructs as cell viability is maintained and the formation of a stable and multi-layered EC network is supported.