Chronic pressure overload results in morphological and functional changes in the right ventricle. Four weeks after pulmonary artery banding, UCB-MNCs were transplanted into the right ventricle. Body weights and temperatures were recorded at baseline and two, four, six and eight weeks (A, B). There was no significant difference in weight gain between the control, PAB-only and PAB + cells groups. The data depict six animals in each group. (C) Wet weight of whole heart was recorded eight weeks after pulmonary artery banding. A comparison was made between cell transplanted and PAB-only groups. A trend towards increase in heart weight was observed in the cell transplanted group (n = 6; P >0.5). (D) The PAB model was validated prior to cell delivery. After PAB, the right ventricle is exposed to pressure overload by pulmonary outflow tract stenosis resulting in right ventricular dilation (E). PAB, pulmonary artery banding; UCB-MNCs, umbilical cord blood-mononuclear cells.