Formation of Lung Alveolar-Like Structures in Collagen–Glycosaminoglycan Scaffolds in Vitro

Abstract

The objective of this study was to investigate the histology of tissue formed when fetal rat lung cells were grown in a collagen-glycosaminoglycan (GAG) tissue-engineering scaffold. The goal was the formation of lung histotypic structures in the tissue-engineering scaffolds in vitro. Achieving this goal would facilitate future investigations of the effects of selected scaffold design parameters on processes that may underlie aspects of lung regeneration in vivo. Lung cells were obtained from Sprague-Dawley rats after 16 and 19 days of gestation. These dissociated cells were seeded into type I collagen-chondroitin 6-sulfate matrices, 8 mm in diameter by 2 mm in thickness, cross-linked and sterilized by dehydrothermal treatment. Approximately 28 million cells were seeded into each spongelike sample. Histological and immunohistochemical studies were performed at termination periods of 2 days and 1, 2, and 3 weeks. The enzymatically dissociated 19-day gestation fetal rat lung cells formed and maintained alveolar-like structures, 50-60 microm in diameter, in the collagen- GAG scaffold. A novel finding was that all of the cell-seeded scaffolds underwent cell-mediated contraction that appeared to be associated with the finding by immunohistochemistry of expression of alpha-smooth muscle actin in some cells. These results demonstrate the capability of dissociated lung cells to form lung histotypic structures in collagen-GAG tissue-engineering scaffolds in vitro. This culture system may be of value in facilitating exploration of strategies for preparing such scaffolds for the regeneration of lung tissue in vivo.

Influence of Acellular Natural Lung Matrix on Murine Embryonic Stem Cell Differentiation and Tissue Formation

“…At present the development of lung tissue equivalents has not been significant, and only a few reports provide evidence of development of in vitro or in vivo engineered lung. [3][4][5][6][7][8] All of these studies utilized simple matrices that were not designed to meet the requirements for lung in terms of matrix composition, elasticity, or porosity. 9,10 Decellularized tissues and organs have been used successfully as scaffolds for engineering a variety of tissues.…”

Computational and bioengineered lungs as alternatives to whole animal, isolated organ, and cell-based lung models

“…Porous PF-127 scaffolds seeded with lung progenitor cells produced alveolar structures morphologically similar to lung tissue following in vivo implantation (34). Others have achieved similar results using an injectable polymer or a collagen-glycosaminoglycan scaffold, showing the capability of lung cells to reproduce lung structures when seeded in an open porous scaffold (2,22).…”

Coming to terms with tissue engineering and regenerative medicine in the lung

“…An obvious advantage of using such synthetic material is the ability to tailor their chemical and biological properties with additional manipulation to achieve desirable mechanical properties. For example, pluronic-based scaffolds seeded with lung progenitor cells, inject able polymers, and collagen-GAG scaffolds have been used to mimic alveolar structures (6,34,35) and allow in vivo implantation (35). However, realization of such approaches toward stable, implantable structures is still investigational.…”