Hyperbaric oxygen treatment of tissue-engineered mucosa enhances secretion of angiogenic factors in vitro

The survival of tissue-engineered mucosa (TEM) after implantation is mostly dependent on the presence of blood vessels for continuous oxygen supply. Therefore the stimulation of vascularization of TEM is essential to improve survival in vivo. Hyperbaric oxygen (HBO) treatment, used to improve wound healing, stimulates the secretion of angiogenic factors. In this study we evaluated the effect of daily HBO treatments on TEM for 1, 3, or 5 consecutive days. Overall histology with hematoxylin-eosin staining showed no apparent changes after one treatment. After three and five HBO treatments, the basal layer became irregular and pyknotic cells were observed. Measurements of the viable epithelium showed significant thinning after one and five treatments, however, proliferation was not affected. The angiogenic factors keratinocyte growth factor (KGF), hepatocyte growth factor (HGF), basic fibroblast growth factor (FGFbasic), and placental growth factor (PlGF) were significantly increased after one HBO treatment, whereas after three treatments a significant decrease of FGFbasic and PlGF was seen. After five treatments KGF, PlGF, and vascular endothelial growth factor (VEGF) were significantly increased. One HBO treatment of TEM enhances the secretion of important angiogenic factors, hereby potentially improving the survival rate after in vivo implantation.