Controlled formation of biological tubule systems in extracellular matrix gels in vitro

Schumacher, Karl; Phua, Siew Cheng; Schumacher, Annegret; Ying, Jackie Y.

doi:10.1038/ki.2008.20

Cited by 18 publications

(17 citation statements)

References 19 publications

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“…10–12 In the lung, hollow epithelial cysts, or alveoli, are clustered at the distal end of bronchioles. Maturation of alveoli occurs postnatally, with secondary septa separating the smooth rudimentary alveoli into many open-sided polyhedra that share a common duct space.…”

Section: Introductionmentioning

confidence: 99%

In vitro model alveoli from photodegradable microsphere templates

et al. 2015

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Recreating the 3D cyst-like architecture of the alveolar epithelium in vitro has been challenging to achieve in a controlled fashion with primary lung epithelial cells. Here, we demonstrate model alveoli formed within a tunable synthetic biomaterial platform using photodegradable microspheres as templates to create physiologically relevant, cyst structures. Poly(ethylene glycol) (PEG)-based hydrogels were polymerized in suspension to form microspheres on the order of 120 μm in diameter. The gel chemistry was designed to allow erosion of the microspheres with cytocompatible light doses (≤15 min exposure to 10 mW cm−2 of 365 nm light) via cleavage of a photolabile nitrobenzyl ether crosslinker. Epithelial cells were incubated with intact microspheres, modified with adhesive peptide sequences to facilitate cellular attachment to and proliferation on the surface. A tumor-derived alveolar epithelial cell line, A549, completely covered the microspheres after only 24 hours, whereas primary mouse alveolar epithelial type II (ATII) cells took ~3 days. The cell-laden microsphere structures were embedded within a second hydrogel formulation at user defined densities; the microsphere templates were subsequently removed with light to render hollow epithelial cysts that were cultured for an additional 6 days. The resulting primary cysts stained positive for cell–cell junction proteins (β-catenin and ZO-1), indicating the formation of a functional epithelial layer. Typically, primary ATII cells differentiated in culture to the alveolar epithelial type I (ATI) phenotype; however, each cyst contained ~1–5 cells that stained positive for an ATII marker (surfactant protein C), which is consistent with ATII cell numbers in native mouse alveoli. This biomaterial-templated alveoli culture system should be useful for future experiments to study lung development and disease progression, and is ideally suited for co-culture experiments where pulmonary fibroblasts or endothelial cells could be presented in the hydrogel surrounding the epithelial cysts.

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Section: Introductionmentioning

confidence: 99%

In vitro model alveoli from photodegradable microsphere templates

et al. 2015

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“…Similarly, the renal tubular cells, when simply entrapped inside a homogeneous collagen gel, could not form tubules, 13a,b,35 while the MDCK cells, when seeded on a grooved collagen-matrigel hydrogel, could self-assemble into short tubular structure. 36 In this regard, the tubular shaped Col HF seemed to create a microenvironment that was more similar to that found under in vivo conditions, and thus provided a good template for leading to the renal tubule formation. Hence, we assumed that the in vivo-like tubular morphology of the bioengineered renal tubules can stimulate their performances on renal function.…”

Section: ■ Discussionmentioning

confidence: 90%

Fabrication of Collagen Gel Hollow Fibers by Covalent Cross-Linking for Construction of Bioengineering Renal Tubules

Shen

Zhang

Wang

et al. 2015

ACS Appl. Mater. Interfaces

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Collagen, the most used natural biomacromolecule, has been extensively utilized to make scaffolds for cell cultures in tissue engineering, but has never been fabricated into the configuration of a hollow fiber (HF) for cell culture due to its poor mechanical properties. In this study, renal tubular cell-laden collagen hollow fiber (Col HF) was fabricated by dissolving sacrificial Ca-alginate cores from collagen shells strengthened by carbodiimide cross-linking. The inner/outer diameters of the Col HF were precisely controlled by the flow rates of core alginate/shell collagen solution in the microfluidic device. As found, the renal tubular cells self-assembled into renal tubules with diameters of 50-200 μm post to the culture in Col HF for 10 days. According to the 3D reconstructed confocal images or HE staining, the renal cells appeared as a tight tubular monolayer on the Col HF inner surface, sustaining more 3D cell morphology than the cell layer on the 2D flat collagen gel surface. Moreover, compared with the cultures in either a Transwell or polymer HF membrane, the renal tubules in Col HF exhibited at least 1-fold higher activity on brush border enzymes of alkaline phosphatase and γ-glutamyltransferase, consistent with their gene expressions. The enhancement occurred similarly on multidrug resistance protein 2 and glucose uptake. Such bioengineered renal tubules in Col HF will present great potential as alternatives to synthetic HF in both clinical use and pharmaceutical investigation.

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“…Kidney epithelial cells are characterized by their polarization, which is represented by the establishment of specific basolateral and luminal surfaces. The authors conclude that this method is feasible for generating kidney epithelial tubules with natural shape and dimensions in a short time [68].…”

Section: Developmental Approachesmentioning

confidence: 94%

Cell-Based Approaches for Renal Tissue Regeneration

Agcaoili¹,

Atala²,

Yoo³

2010

UIJ

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Abbreviations and Acronyms3-D = 3-dimensional ESRD = end-stage renal disease EPO = erythropoietin hAFSC = human amniotic fluid-derived stem cell MSC = mesenchymal stem cell PEC = parietal epithelial cell RT-PCR = reverse transcriptase polymerase chain reaction Sca-1 = stem cell antigen-1 ABSTRACTThe kidneys serve a number of important roles that are required to maintain normal human physiologic function. Chronic kidney disease is a leading cause of mortality and morbidity, and a substantial number of these patients progress to end-stage renal disease. End-stage disease involves multiple organ systems and requires renal replacement therapy. Currently, the gold-standard treatment for this condition is renal transplantation, which can restore complete kidney function. However, renal transplantation is limited by the critical shortage of transplant organs and by complications that can result from chronic immunosuppressive therapy and graft failure. Recent advances in cell technologies have allowed for development of cell-based approaches for kidney tissue regeneration. Efforts are ongoing to identify reliable cell sources, develop ideal growth environments and innovative differentiation factors, and discover synthetic and naturally-derived materials for use as an ideal support structure for tissue regeneration. However, numerous challenges must be met in order to translate these techniques into clinically relevant therapies. UroToday International Journal ® UI J

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Controlled formation of biological tubule systems in extracellular matrix gels in vitro

Cited by 18 publications

References 19 publications

In vitro model alveoli from photodegradable microsphere templates

In vitro model alveoli from photodegradable microsphere templates

Fabrication of Collagen Gel Hollow Fibers by Covalent Cross-Linking for Construction of Bioengineering Renal Tubules

Cell-Based Approaches for Renal Tissue Regeneration

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