AAV-HREEPO–treated EPO-TAg^h transgenic mice display physiological correction of the hematocrit.

(A) Filled symbols represent Epo-TAg^h mice groups; open symbols, healthy mice groups. Circles represent untreated groups showing baseline hematocrit levels of the healthy and Epo-TAg^h mice; squares, AAV-CMVGFP–treated groups showing no change in hematocrit level compared with that of untreated counterparts; diamonds, AAV-CMVEpo–treated groups show a rapid, unregulated rise in the hematocrit leading to fatal polycythemia in 2 mice; triangles, AAV-HREEpo–treated groups. Epo-TAg^h mice responded to AAV-HREEpo treatment with correction of the hematocrit to the normal physiological level, whereas there was no change in hematocrit level in the healthy mice treated with the same AAV-HREEpo vector. Unpaired student t test was used to compare day 7 and day 213 hematocrit measurements. P = .81,P = .36, P = .98, and P = .0001, respectively, for untreated healthy mice, healthy mice + AAVHREEpo, untreated Epo-TAg^h mice, and Epo-TAg^h mice + AAVHREEpo. Hematocrit levels are plotted as a mean value for 6 animals in each treatment group ± SD. (B) Hematocrit data from each individual animal treated with the AAV-HREEpo vector is plotted. ▴ represents Epo-TAg^h mice; ▵, healthy mice.