Peripheral administration of AAV9-mi2.1 prevents increases in plasma lactate dehydrogenase (LDH) in BACHD mice but does not prevent the weight-gain phenotype characteristic of this model. (a) Plasma levels of enzyme LDH, a biomarker for peripheral tissue breakdown, are significantly elevated in 26-week-old, control-treated, female BACHD mice, relative to mi2.1-treated, female BACHD mice (P < 0.01) and saline-injected, female wild-type (WT) mice (P < 0.05) at the same age (males not evaluated). LDH levels in adult female mi2.1 and WT mice were not significantly different (P > 0.05). (b,c) Reducing mHTT levels in peripheral tissues did not prevent weight gain in BACHD mice. AAV9-mi2.1–treated animals' weights were not significantly different compared with AAV9-miSCM control-treated mice (P > 0.05). Both groups of transgenic BACHD mice gained significantly more weight than WT littermates (P < 0.01 for males, P < 0.001 for females). Values indicated are the mean ± SEM. *P < 0.05, **P < 0.01. AAV9, adeno-associated viral vector serotype 9.