Extensive regeneration of the stomach using bioabsorbable polymer sheets

Development of an artificial portal vein using bioabsorbable polymers

PURPOSE

During surgical resection of malignant tumors in the hepatobiliary pancreatic region, portal vein resection and reconstruction may be needed. However, there is no alternative to the portal vein. We therefore developed an artificial portal vein that could be used in the abdominal cavity.

METHODS

In the experiments, hybrid pigs (n = 8) were included. An artificial portal vein was created using a bioabsorbable polymer sheet (BAPS). Subsequently, the portal vein's anterior wall was excised into an elliptical shape. A BAPS in the form of a patch was implanted at the same site. At 2 weeks (n = 3) and 3 months (n = 5) after the implantation, the BAPS implantation site was resected and evaluated macroscopically and histopathologically.

RESULTS

Immediately after the implantation, blood leakage was not detected. Two weeks after implantation, the BAPS remained, and endothelial cells were observed. Thrombus formation was not observed. Three months after implantation, the BAPS had been completely absorbed and was indistinguishable from the surrounding portal vein. Stenosis and aneurysms were not observed.

CONCLUSIONS

BAPS can replace a defective portal vein from the early stage of implantation to BAPS absorption. These results suggest that it can be an alternative material to the portal vein in surgical reconstruction.

Bioengineering and regeneration of gastrointestinal tissue: where are we now and what comes next?

INTRODUCTION

The field of tissue engineering and regenerative medicine has been applied to the gastrointestinal (GI) tract for a couple decades. Several achievements have been accomplished that provide promising tools for treating diseases of the GI tract.

AREAS COVERED

The work described in this review covers the traditional aspect of using cells and scaffolds to replace parts of the tract. Several studies investigated different types of biomaterials and different types of cells. A more recent approach involved the use of gut-derived organoid units that can differentiate into all gut cell layers. The most recent approach introduced the use of organ-on-a-chip concept to understand the physiology and pathophysiology of the GI system.

EXPERT OPINION

The different approaches tackle the diseases of the GI tract from different perspectives. While all these different approaches provide a promising and encouraging future for this field, the translational aspect is yet to be studied.

Contribution of Wound-Associated Cells and Mediators in Orchestrating Gastrointestinal Mucosal Wound Repair

The gastrointestinal mucosa, structurally formed by the epithelium and lamina propria, serves as a selective barrier that separates luminal contents from the underlying tissues. Gastrointestinal mucosal wound repair is orchestrated by a series of spatial and temporal events that involve the epithelium, recruited immune cells, resident stromal cells, and the microbiota present in the wound bed. Upon injury, repair of the gastrointestinal barrier is mediated by collective migration, proliferation, and subsequent differentiation of epithelial cells. Epithelial repair is intimately regulated by a number of wound-associated cells that include immune cells and stromal cells in addition to mediators released by luminal microbiota. The highly regulated interaction of these cell types is perturbed in chronic inflammatory diseases that are associated with impaired wound healing. An improved understanding of prorepair mechanisms in the gastrointestinal mucosa will aid in the development of novel therapeutics that promote mucosal healing and reestablish the critical epithelial barrier function.

Bioengineering the gut: future prospects of regenerative medicine

Functions of the gastrointestinal tract include motility, digestion and absorption of nutrients. These functions are mediated by several specialized cell types including smooth muscle cells, neurons, interstitial cells and epithelial cells. In gastrointestinal diseases, some of the cells become degenerated or fail to accomplish their normal functions. Surgical resection of the diseased segments of the gastrointestinal tract is considered the gold-standard treatment in many cases, but patients might have surgical complications and quality of life can remain low. Tissue engineering and regenerative medicine aim to restore, repair, or regenerate the function of the tissues. Gastrointestinal tissue engineering is a challenging process given the specific phenotype and alignment of each cell type that colonizes the tract - these properties are critical for proper functionality. In this Review, we summarize advances in the field of gastrointestinal tissue engineering and regenerative medicine. Although the findings are promising, additional studies and optimizations are needed for translational purposes.