Effect of LV-SF-GAA HSC transplantation on cardiac structure and parameters. (A-B) Response of cardiac hypertrophy to LV-SF-GAA transplantation. The right and left ventricular mass of 10-month-old (n = 6 in all groups) and 15-month-old (n = 5 for LV-SF-GFP and n = 7 for LV-SF-GAA) mice that received a transplant of LV-SF-GFP is significantly higher than for WT mice. The left ventricular mass of mice that received a transplant of LV-SF-GAA is significantly lower than for the age-matched mice that received a transplant of LV-SF-GFP. The same holds for the right ventricular mass at month 15 (*P < .05, **P < .01, or ***P < .01 indicate a significant difference between groups). (C) Representative ultrasound images display the short axis of the left ventricle (left, 2-dimensional guided; right, M-mode) of WT and Gaa^−/− mice that received a transplant of LV-SF-GFP and LV-SF-GAA (W indicates ventricular wall; L, left ventricular lumen). The Gaa^−/− mice that received a transplant of LV-SF-GFP display a larger left ventricular wall thickness than the WT mice and mice that received a transplant of LV-SF-GAA, both at end diastole and at end systole (not shown). Furthermore, it shows that mice that received a transplant of LV-SF-GFP have a lower heart rate than both the WT mice and mice that received a transplant of LV-SF-GAA by the increased duration of the cardiac cycle. (D) The left ventricular wall thickness at end diastole (LV_EDT) in LV-SF-GFP–treated mice (n = 6) is increased compared with WT mice at 8 and 10 months of age (n = 6). Reduction of LV_EDT is accomplished in mice that received a transplant of LV-SF-GAA compared with LV-SF-GFP–treated mice at 8 (n = 6), 10 (n = 6), and 15 months of age (n = 3) (**P < .01). (E) Relative heart rate normalized after LV-SF-GAA treatment. At 10 months of age LV-SF-GFP–treated mice (n = 10) had a lower than normal (WT mice; n = 11) heart rate. Treatment with LV-SF-GAA (n = 11) normalized the heart rate (**P < .01). BPM indicates beats per minute.