Thymosin β4 Improves Differentiation and Vascularization of EHTs

Figure 4

Increased vascularization and contractility in engineered heart tissue under Thymosin β4 treatment. (a) Cross sections of EHTs from reporter mice expressing LacZ in endothelial cells (Cdh5-CreERT2 × Rosa26-LacZ) reveal an increase in capillary density if treated with Tβ4. (b and c) AAV-mediated transfection with Tβ4 (rAAV.Tβ4, versus rAAV.GFP as control) of EHTs implanted into skinfold chambers leads to an increase of graft-vascularization, both 5 and 8 days after implantation ( per group, ; ). (d) Images of whole skinfold chambers containing EHTs generated from LacZ reporter mice show little sprouting of graft resident endothelial cells into host tissue, while rAAV.Tβ4 treatment drastically induces angiogenic sprouting into the host tissue of skinfold chambers (dotted lines indicate the graft/host border). (e) Treatment with rAAV.Tβ4 leads to an increase of spontaneous contractions in implanted EHTs compared to rAAV.GFP control ( per group, ).