pH regulates the lumen diameter of tissue-engineered capillaries.

Angiogenesis is vital in tissue engineering and the size of the capillary lumen diameter directly affects vascular function. Therefore, the involvement of the pH in the regulation of the capillary lumen diameter was investigated in the present study. The cytosolic pH of different pH medium groups was measured using flow cytometry. Bromodeoxyuridine staining and wound-healing assays were performed to detect cell proliferation and migration, respectively. The expression of angiogenesis-related genes was detected using reverse transcription-quantitative PCR. In addition, cell tube formation under different pH conditions was assessed using a tube formation assay and a 3D Matrigel model. The results indicated that a change in the pH value of the culture medium affected the cytosolic pH of the endothelial cells, which then led to a change in vascular diameter. When the medium's pH ranged from 7.4 to 7.6, the diameter of the lumen formed in the Matrigel was suitable for capillary formation in tissue engineering. The present results revealed an important role for the pH in the process of capillary formation and provided insight for pH regulation during endothelial cell tube formation and angiogenesis in tissue engineering.