Right ventricular dysfunction in the R6/2 transgenic mouse model of Huntington's disease is unmasked by dobutamine.

BACKGROUND

Increasingly, evidence from studies in both animal models and patients suggests that cardiovascular dysfunction is important in HD. Previous studies measuring function of the left ventricle (LV) in the R6/2 model have found a clear cardiac abnormality, albeit with preserved LV systolic function. It was hypothesized that an impairment of RV function might play a role in this condition via mechanisms of ventricular interdependence.

OBJECTIVE

To investigate RV function in the R6/2 mouse model of Huntington's disease (HD).

METHODS

Cardiac cine-magnetic resonance imaging (MRI) was used to determine functional parameters in R6/2 mice. In a first experiment, these parameters were derived longitudinally to determine deterioration of cardiac function with disease progression. A second experiment compared the response to a stress test (using dobutamine) of wildtype and early-symptomatic R6/2 mice.

RESULTS

There was progressive deterioration of RV systolic function with age in R6/2 mice. Furthermore, beta-adrenergic stimulation with dobutamine revealed RV dysfunction in R6/2 mice before any overt symptoms of the disease were apparent.

CONCLUSIONS

This work adds to accumulating evidence of cardiovascular dysfunction in R6/2 mice, describing for the first time the involvement of the right ventricle. Cardiovascular dysfunction should be considered, both when treatment strategies are being designed, and when searching for biomarkers for HD.