Angiogenesis, cell differentiation and cell survival in tissue engineering and cancer research

Prostaglandin F-2α Stimulates The Secretion of Vascular Endothelial Growth Factor and Induces Cell Proliferation and Migration of Adipose Tissue Derived Mesenchymal Stem Cells

Objective

Tissue engineering today uses factors that can induce differentiation of mesenchymal stem cells (MSCs) into other cell types. However, the problem of angiogenesis in this differentiated tissue remains an unresolved area of research interest. The aim of this study was to investigate the effects of prostaglandin F-2α (PGF-2α) on the expression of vascular endothelial growth factor (VEGF) in human adipose tissue derived MSCs.

Materials and Methods

In this experimental research, human adipose tissue was digested using collagenase. The isolated MSCs cells were treated with PGF-2α (up to 5 μg/ml) and incubated for 96 hours. Cell proliferation, secretion of VEGF and cell migration were spontaneously assayed by MTT, BrdU, ELISA, RT-PCR and scratching methods.

Results

Cell growth at 1.0, 2.5, 5 µg/ml of PGF-2α was not significantly reduced compared to control cells, suggesting that these concentrations of PGF-2α are not toxic to cell growth. The results of the BrdU incorporation assay indicated that, in comparison to untreated cells, BrdU incorporation was respectively 1.08, 1.96, 2.0 and 1.8 fold among cells treated with 0.1, 1.0, 2.5 and 5.0 µg/ml of PGF-2α. The scratching test also demonstrated a positive influence on cell proliferation and migration. Cells treated with 1.0 µg/ml of PGF-2α for 12 hours showed the highest relative migration and coverage in comparison to untreated cells. Quantitative VEGF ELISA and RT- PCR results indicated an increase in VEGF expression and secretion in the presence of PGF-2α. The amount of VEGF produced in response to 0.1, 1.0, 2.5 and 5.0 µg/ml of PGF-2α was 62.4 ± 3.2 , 66.3 ± 3.7, 53.1 ± 2.6 and 49.0 ± 2.3 pg/ml, respectively, compared to the 35.2 ± 2.1 pg/ml produced by untreated cells.

Conclusion

Stimulation of VEGF secretion by PGF-2α treated MSCs could be useful for the induction of angiogenesis in tissue engineering in vitro.

Clinic application of tissue engineered bronchus for lung cancer treatment

BACKGROUND

Delayed revascularization process and substitute infection remain to be key challenges in tissue engineered (TE) airway reconstruction. We propose an "in-vivo bioreactor" design, defined as an implanted TE substitutes perfused with an intra-scaffold medium flow created by an extracorporeal portable pump system for in situ organ regeneration. The perfusate keeps pre-seeded cells alive before revascularization. Meanwhile the antibiotic inside the perfusate controls topical infection.

METHODS

A stage IIIA squamous lung cancer patient received a 5-cm TE airway substitute, bridging left basal segment bronchus to carina, with the in-vivo bioreactor design to avoid left pneumonectomy. Continuous intra-scaffold Ringer's-gentamicin perfusion lasted for 1 month, together with orthotopic peripheral total nucleated cells (TNCs) injection twice a week.

RESULTS

The patient recovered uneventfully. Bronchoscopy follow-up confirmed complete revascularization and reepithelialization four months postoperatively. Perfusate waste test demonstrated various revascularization growth factors secreted by TNCs. The patient received two cycles of chemotherapy and 30 Gy radiotherapy thereafter without complications related to the TE substitute.

CONCLUSIONS

In-vivo bioreactor design combines the traditionally separated in vitro 3D cell-scaffold culture system and the in vivo regenerative processes associated with TE substitutes, while treating the recipients as bioreactors for their own TE prostheses. This design can be applied clinically. We also proved for the first time that TE airway substitute is able to tolerate chemo-radiotherapy and suitable to be used in cancer treatment.