Decellularized esophageal tubular scaffold microperforated by quantum molecular resonance technology and seeded with mesenchymal stromal cells for tissue engineering esophageal regeneration

Current surgical options for patients requiring esophageal replacement suffer from several limitations and do not assure a satisfactory quality of life. Tissue engineering techniques for the creation of customized “self-developing” esophageal substitutes, which are obtained by seeding autologous cells on artificial or natural scaffolds, allow simplifying surgical procedures and achieving good clinical outcomes. In this context, an appealing approach is based on the exploitation of decellularized tissues as biological matrices to be colonized by the appropriate cell types to regenerate the desired organs. With specific regard to the esophagus, the presence of a thick connective texture in the decellularized scaffold hampers an adequate penetration and spatial distribution of cells. In the present work, the Quantum Molecular Resonance^® (QMR) technology was used to create a regular microchannel structure inside the connective tissue of full-thickness decellularized tubular porcine esophagi to facilitate a diffuse and uniform spreading of seeded mesenchymal stromal cells within the scaffold. Esophageal samples were thoroughly characterized before and after decellularization and microperforation in terms of residual DNA content, matrix composition, structure and biomechanical features. The scaffold was seeded with mesenchymal stromal cells under dynamic conditions, to assess the ability to be repopulated before its implantation in a large animal model. At the end of the procedure, they resemble the original esophagus, preserving the characteristic multilayer composition and maintaining biomechanical properties adequate for surgery. After the sacrifice we had histological and immunohistochemical evidence of the full-thickness regeneration of the esophageal wall, resembling the native organ. These results suggest the QMR microperforated decellularized esophageal scaffold as a promising device for esophagus regeneration in patients needing esophageal substitution.

Successful muscle regeneration by a homologous microperforated scaffold seeded with autologous mesenchymal stromal cells in a porcine esophageal substitution model

BACKGROUND

Since the esophagus has no redundancy, congenital and acquired esophageal diseases often require esophageal substitution, with complicated surgery and intestinal or gastric transposition. Peri-and-post-operative complications are frequent, with major problems related to the food transit and reflux. During the last years tissue engineering products became an interesting therapeutic alternative for esophageal replacement, since they could mimic the organ structure and potentially help to restore the native functions and physiology. The use of acellular matrices pre-seeded with cells showed promising results for esophageal replacement approaches, but cell homing and adhesion to the scaffold remain an important issue and were investigated.

METHODS

A porcine esophageal substitute constituted of a decellularized scaffold seeded with autologous bone marrow-derived mesenchymal stromal cells (BM-MSCs) was developed. In order to improve cell seeding and distribution throughout the scaffolds, they were micro-perforated by Quantum Molecular Resonance (QMR) technology (Telea Electronic Engineering).

RESULTS

The treatment created a microporous network and cells were able to colonize both outer and inner layers of the scaffolds. Non seeded (NSS) and BM-MSCs seeded scaffolds (SS) were implanted on the thoracic esophagus of 4 and 8 pigs respectively, substituting only the muscle layer in a mucosal sparing technique. After 3 months from surgery, we observed an esophageal substenosis in 2/4 NSS pigs and in 6/8 SS pigs and a non-practicable stricture in 1/4 NSS pigs and 2/8 SS pigs. All the animals exhibited a normal weight increase, except one case in the SS group. Actin and desmin staining of the post-implant scaffolds evidenced the regeneration of a muscular layer from one anastomosis to another in the SS group but not in the NSS one.

CONCLUSIONS

A muscle esophageal substitute starting from a porcine scaffold was developed and it was fully repopulated by BM-MSCs after seeding. The substitute was able to recapitulate in shape and function the original esophageal muscle layer.

Thyroid hormone T3 counteracts STZ induced diabetes in mouse

This study intended to demonstrate that the thyroid hormone T3 counteracts the onset of a Streptozotocin (STZ) induced diabetes in wild type mice. To test our hypothesis diabetes has been induced in Balb/c male mice by multiple low dose Streptozotocin injection; and a group of mice was contemporaneously injected with T3. After 48 h mice were tested for glucose tolerance test, insulin serum levels and then sacrified. Whole pancreata were utilized for morphological and biochemical analyses, while protein extracts and RNA were utilized for expression analyses of specific molecules. The results showed that islets from T3 treated mice were comparable to age- and sex-matched control, untreated mice in number, shape, dimension, consistency, ultrastructure, insulin and glucagon levels, Tunel positivity and caspases activation, while all the cited parameters and molecules were altered by STZ alone. The T3-induced pro survival effect was associated with a strong increase in phosphorylated Akt. Moreover, T3 administration prevented the STZ-dependent alterations in glucose blood level, both during fasting and after glucose challenge, as well as in insulin serum level. In conclusion we demonstrated that T3 could act as a protective factor against STZ induced diabetes.