A novel 3D in vitro model of the human gut microbiota

Francesco Biagini,Anna Lapomarda,Marco Calvigioni,Diletta Mazzantini,Francesca Montemurro,Francesco Celandroni,Giovanni Vozzi,Monica Mattioli-Belmonte,Emilia Ghelardi,Carmelo De Maria,Alessandra Vecchione,Chiara Magliaro

doi:10.1038/s41598-020-78591-w

Francesco Biagini, Anna Lapomarda + Show 10 more

Open Access

https://doi.org/10.1038/s41598-020-78591-w

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Abstract

Clinical trials and animal studies on the gut microbiota are often limited by the difficult access to the gut, restricted possibility of in vivo monitoring, and ethical issues. An easily accessible and monitorable in vitro model of the gut microbiota represents a valid tool for a wider comprehension of the mechanisms by which microbes interact with the host and with each other. Herein, we present a novel and reliable system for culturing the human gut microbiota in vitro. An electrospun gelatin structure was biofabricated as scaffold for microbial growth. The efficiency of this structure in supporting microbial proliferation and biofilm formation was initially assessed for five microbes commonly inhabiting the human gut. The human fecal microbiota was then cultured on the scaffolds and microbial biofilms monitored by confocal laser and scanning electron microscopy and quantified over time. Metagenomic analyses and Real-Time qPCRs were performed to evaluate the stability of the cultured microbiota in terms of qualitative and quantitative composition. Our results reveal the three-dimensionality of the scaffold-adhered microbial consortia that maintain the bacterial biodiversity and richness found in the original sample. These findings demonstrate the validity of the developed electrospun gelatin-based system for in vitro culturing the human gut microbiota.

Highlights

Clinical trials and animal studies on the gut microbiota are often limited by the difficult access to the gut, restricted possibility of in vivo monitoring, and ethical issues
Intestinal microorganisms attend to short chain fatty acid (SCFA) production, cofactor and vitamin biosynthesis, bile salts transformation, and production of enzymes able to transform dietary complex polysaccharides into structurally simpler carbohydrates, which otherwise would not be digested or absorbed[3,4]
The average diameter of the fibers constituting the scaffold was estimated through scanning electron microscopy (SEM) imaging (Fig. 1c)

Summary

Introduction

Clinical trials and animal studies on the gut microbiota are often limited by the difficult access to the gut, restricted possibility of in vivo monitoring, and ethical issues. Our results reveal the three-dimensionality of the scaffold-adhered microbial consortia that maintain the bacterial biodiversity and richness found in the original sample These findings demonstrate the validity of the developed electrospun gelatin-based system for in vitro culturing the human gut microbiota. Studies on these models can be limited by crucial species-specific differences, involving e.g. a different diet and eating f requency[14] Due to their technical reproducibility, easy access and m onitoring[15], in vitro models represent a valid alternative to study the microbial behavior of the human gut microbiota. Some in vitro models were proposed for culturing complex microbial populations as those residing in the gut (e.g. TIM-221, SHIME22, Three-Stage Continuous S ystem23), no attempts have been made to use electrospun structures as scaffolds for microbial adhesion and growth

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