Dataset Information

Stromal Cells in Dense Collagen Promote Cardiomyocyte and Microvascular Patterning in Engineered Human Heart Tissue.

ABSTRACT: Cardiac tissue engineering is a strategy to replace damaged contractile tissue and model cardiac diseases to discover therapies. Current cardiac and vascular engineering approaches independently create aligned contractile tissue or perfusable vasculature, but a combined vascularized cardiac tissue remains to be achieved. Here, we sought to incorporate a patterned microvasculature into engineered heart tissue, which balances the competing demands from cardiomyocytes to contract the matrix versus the vascular lumens that need structural support. Low-density collagen hydrogels (1.25 mg/mL) permit human embryonic stem cell-derived cardiomyocytes (hESC-CMs) to form a dense contractile tissue but cannot support a patterned microvasculature. Conversely, high collagen concentrations (density ≥6 mg/mL) support a patterned microvasculature, but the hESC-CMs lack cell-cell contact, limiting their electrical communication, structural maturation, and tissue-level contractile function. When cocultured with matrix remodeling stromal cells, however, hESC-CMs structurally mature and form anisotropic constructs in high-density collagen. Remodeling requires the stromal cells to be in proximity with hESC-CMs. In addition, cocultured cardiac constructs in dense collagen generate measurable active contractions (on the order of 0.1 mN/mm(2)) and can be paced up to 2 Hz. Patterned microvascular networks in these high-density cocultured cardiac constructs remain patent through 2 weeks of culture, and hESC-CMs show electrical synchronization. The ability to maintain microstructural control within engineered heart tissue enables generation of more complex features, such as cellular alignment and a vasculature. Successful incorporation of these features paves the way for the use of large scale engineered tissues for myocardial regeneration and cardiac disease modeling.

SUBMITTER: Roberts MA

PROVIDER: S-EPMC4840925 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Background:The seeding of scaffolds with the stromal vascular fraction (SVF) of adipose tissue is a common prevascularization strategy in tissue engineering. Alternatively, adipose tissue-derived microvascular fragments (ad-MVF) may serve as vascularization units. In contrast to SVF single cells, they represent a mixture of intact arteriolar, capillary and venular vessel segments. Therefore, we herein hypothesized that the ad-MVF-based prevascularization of scaffolds is superior to the conventional SVF single cells-based approach. Results:SVF single cells and ad-MVF were enzymatically isolated from epididymal fat pads of green fluorescent protein (GFP)+ donor mice to assess their viability and cellular composition using fluorescence microscopy and flow cytometry. Moreover, collagen-glycosaminoglycan matrices (Integra®) were seeded with identical amounts of the isolates and implanted into full-thickness skin defects within dorsal skinfold chambers of GFP- recipient mice for the intravital fluorescent microscopic, histological and immunohistochemical analysis of implant vascularization and incorporation throughout an observation period of 2 weeks. Non-seeded matrices served as controls. While both isolates contained a comparable fraction of endothelial cells, perivascular cells, adipocytes and stem cells, ad-MVF exhibited a significantly higher viability. After in vivo implantation, the vascularization of ad-MVF-seeded scaffolds was improved when compared to SVF-seeded ones, as indicated by a significantly higher functional microvessel density. This was associated with an enhanced cellular infiltration, collagen content and density of CD31+/GFP+ microvessels particularly in the center of the implants, demonstrating a better incorporation into the surrounding host tissue. In contrast, non-seeded matrices exhibited a poor vascularization, incorporation and epithelialization over time. Conclusions:The present study demonstrates that ad-MVF are highly potent vascularization units that markedly accelerate and improve scaffold vascularization when compared to the SVF.

Project description:Different tissue-engineering approaches have been developed to induce and promote cardiac regeneration; however, the impact of the immune system and its responses to the various scaffold components of the engineered grafts remains unclear. Fibrin-based engineered heart tissue (EHT) was generated from neonatal Lewis (Lew) rat heart cells and transplanted onto the left ventricular surface of three different rat strains: syngeneic Lew, allogeneic Brown Norway, and immunodeficient Rowett Nude rats. Interferon spot frequency assay results showed similar degrees of systemic immune activation in the syngeneic and allogeneic groups, whereas no systemic immune response was detectable in the immunodeficient group (p < .001 vs. syngeneic and allogeneic). Histological analysis revealed much higher local infiltration of CD3- and CD68-positive cells in syngeneic and allogeneic rats than in immunodeficient animals. Enzyme-linked immunospot and immunofluorescence experiments revealed matrix-directed TH1-based rejection in syngeneic recipients without collateral impairment of heart cell survival. Bioluminescence imaging was used for in vivo longitudinal monitoring of transplanted luciferase-positive EHT constructs. Survival was documented in syngeneic and immunodeficient recipients for a period of up to 110 days after transplant, whereas in the allogeneic setting, graft survival was limited to only 14 ± 1 days. EHT strategies using autologous cells are promising approaches for cardiac repair applications. Although fibrin-based scaffold components elicited an immune response in our studies, syngeneic cells carried in the EHT were relatively unaffected.An initial insight into immunological consequences after transplantation of engineered heart tissue was gained through this study. Most important, this study was able to demonstrate cell survival despite rejection of matrix components. Generation of syngeneic human engineered heart tissue, possibly using human induced pluripotent stem cell technology with subsequent directed rejection of matrix components, may be a potential future approach to replace diseased myocardium.

Dataset Information

Stromal Cells in Dense Collagen Promote Cardiomyocyte and Microvascular Patterning in Engineered Human Heart Tissue.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets