Bioengineered prosthesis with allogenic heterotopic fibroblasts for cricoid regeneration

Implantation of Induced Pluripotent Stem Cell-Derived Tracheal Epithelial Cells

OBJECTIVES

Compared with using autologous tissue, the use of artificial materials in the regeneration of tracheal defects is minimally invasive. However, this technique requires early epithelialization on the inner side of the artificial trachea. After differentiation from induced pluripotent stem cells (iPSCs), tracheal epithelial tissues may be used to produce artificial tracheas. Herein, we aimed to demonstrate that after differentiation from fluorescent protein-labeled iPSCs, tracheal epithelial tissues survived in nude rats with tracheal defects.

METHODS

Red fluorescent tdTomato protein was electroporated into mouse iPSCs to produce tdTomato-labeled iPSCs. Embryoid bodies derived from these iPSCs were then cultured in differentiation medium supplemented with growth factors, followed by culture on air-liquid interfaces for further differentiation into tracheal epithelium. The cells were implanted with artificial tracheas into nude rats with tracheal defects on day 26 of cultivation. On day 7 after implantation, the tracheas were exposed and examined histologically.

RESULTS

Tracheal epithelial tissue derived from tdTomato-labeled iPSCs survived in the tracheal defects. Moreover, immunochemical analyses showed that differentiated tissues had epithelial structures similar to those of proximal tracheal tissues.

CONCLUSIONS

After differentiation from iPSCs, tracheal epithelial tissues survived in rat bodies, warranting the use of iPSCs for epithelial regeneration in tracheal defects.

Sparing Surgery for the Successful Treatment of Thyroid Papillary Carcinoma Invading the Trachea: A Case Report

Published reports on salvage treatment for trachea reconstruction after total thyroidectomy or partial tracheotomy are available, some of them using structures of the trachea itself, auricular cartilage, a musculocutaneous flap, or other methods. In our report, we emphasize the importance of a search for a new material and approach for sparing surgery. The purpose of this article is to describe a case of a successful sparing surgery in a patient with advanced thyroid papillary carcinoma invading the trachea. After total thyroidectomy in 2012, partial resection of the trachea was performed in 2014. The lesion defect was 5.5 × 2.3 cm in size, located between 4 (2nd–6th) tracheal cartilaginous rings and involving about a semicircumference. It was reconstructed with the aid of the knitted TiNi-based mesh endograft, which has been prefabricated in the sternocleidomastoid muscle and further covered with the skin draped over the wound. The tracheostoma was fully closed 6 weeks after the surgery. There were neither side effects nor complications. This kind of tracheal surgery for extensive lesions demonstrates good functional and cosmetic outcomes.

Regeneration of tracheal epithelium using mouse induced pluripotent stem cells

Conclusion The findings demonstrated the potential use of induced pluripotent stem cells for regeneration of tracheal epithelium. Objective Autologous tissue implantation techniques using skin or cartilage are often applied in cases of tracheal defects with laryngeal inflammatory lesions and malignant tumor invasion. However, these techniques are invasive with an unstable clinical outcome. The purpose of this study was to investigate regeneration in a tracheal defect site of nude rats after implantation of ciliated epithelium that was differentiated from induced pluripotent stem cells. Method Embryoid bodies were formed from mouse induced pluripotent stem cells. They were cultured with growth factors for 5 days, and then cultured at the air-liquid interface. The degree of differentiation achieved prior to implantation was determined by histological findings and the results of real-time polymerase chain reaction. Embryoid bodies including ciliated epithelium were embedded into collagen gel that served as an artificial scaffold, and then implanted into nude rats, creating an 'air-liquid interface model'. Histological evaluation was performed 7 days after implantation. Results The ciliated epithelial structure survived on the lumen side of regenerated tissue. It was demonstrated histologically that the structure was composed of ciliated epithelial cells.

Tubular organ epithelialisation

Hollow, tubular organs including oesophagus, trachea, stomach, intestine, bladder and urethra may require repair or replacement due to disease. Current treatment is considered an unmet clinical need, and tissue engineering strategies aim to overcome these by fabricating synthetic constructs as tissue replacements. Smart, functionalised synthetic materials can act as a scaffold base of an organ and multiple cell types, including stem cells can be used to repopulate these scaffolds to replace or repair the damaged or diseased organs. Epithelial cells have not yet completely shown to have efficacious cell-scaffold interactions or good functionality in artificial organs, thus limiting the success of tissue-engineered grafts. Epithelial cells play an essential part of respective organs to maintain their function. Without successful epithelialisation, hollow organs are liable to stenosis, collapse, extensive fibrosis and infection that limit patency. It is clear that the source of cells and physicochemical properties of scaffolds determine the successful epithelialisation. This article presents a review of tissue engineering studies on oesophagus, trachea, stomach, small intestine, bladder and urethral constructs conducted to actualise epithelialised grafts.

Construction of tissue-engineered laryngeal cartilage with a hollow, semi-flared shape using poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) as a scaffold

The aim of the present study was to construct tissue-engineered laryngeal cartilage with a hollow, semi-flared shape using a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHH) scaffold. Porous PHBHH was prepared and formed into a hollow, semi-flared shape, and the cell-material composites were cultured for one week in vitro prior to implantation in vivo. Cells of the nine rabbits of the experimental group were filled and encapsulated in the myofascial flap-shaping material composite for in situ implantation. The three rabbits in the control group were treated with the shaping material without the chondrocytes. Cartilage regeneration was assessed at six, 12 and 18 weeks after surgery. In the experimental group, the shape and porosity of the material were ideal, the cells exhibited good adhesion with the material and the myofascial flap blood supply was rich. The engineered laryngeal cartilage with the hollow, semi-flared shape was ideally formed, and the cartilage formed at six weeks after the surgery. Further maturation of the cartilage was observed at 12 and 18 weeks after the surgery. PHBHH was a suitable material for the formation of a hollow, semi-flared shape with good cellular compatibility. Myofascial flap filling and wrapping can be used to build tissue-engineered laryngeal cartilage with a hollow, semi-flared shape.

Airway tissue engineering: an update

INTRODUCTION

Prosthetic materials, autologous tissues, cryopreserved homografts and allogeneic tissues have thus far proven unsuccessful in providing long-term functional solutions to extensive upper airway disease and damage. Research is therefore focusing on the rapidly expanding fields of regenerative medicine and tissue engineering in order to provide stem cell-based constructs for airway reconstruction, substitution and/or regeneration.

AREAS COVERED

Advances in stem cell technology, biomaterials and growth factor interactions have been instrumental in guiding optimization of tissue-engineered airways, leading to several first-in-man studies investigating stem cell-based tissue-engineered tracheal transplants in patients. Here, we summarize current progress, outstanding research questions, as well as future directions within the field.

EXPERT OPINION

The complex immune interaction between the transplant and host in vivo is only beginning to be untangled. Recent progress in our understanding of stem cell biology, decellularization techniques, biomaterials and transplantation immunobiology offers the prospect of transplanting airways without the need for lifelong immunosuppression. In addition, progress in airway revascularization, reinnervation and ever-increasingly sophisticated bioreactor design is opening up new avenues for the construction of a tissue-engineered larynx. Finally, 3D printing is a novel technique with the potential to render microscopic control over how cells are incorporated and grown onto the tissue-engineered airway.

Stem cell-based organ replacements-airway and lung tissue engineering

Tissue engineering requires the use of cells seeded onto scaffolds, often in conjunction with bioactive molecules, to regenerate or replace tissues. Significant advances have been made in recent years within the fields of stem cell biology and biomaterials, leading to some exciting developments in airway tissue engineering, including the first use of stem cell-based tissue-engineered tracheal replacements in humans. In addition, recent advances within the fields of scaffold biology and decellularization offer the potential to transplant patients without the use of immunosuppression.