Blood pressure is measured by tail-cuff using the CODA high throughput non-invasive BP system (Kent Scientific), detailed previously21 (link)58 (link). Briefly, the animal is placed in individual holders at least 10 minutes prior to obtaining pressure measurements. Acclimatization is accomplished through training sessions. BP measurements were taken every two weeks throughout the duration of the survival study (9 months). A minimum of 10 readings were taken, and the mean of acceptable readings (as determined by the software instrument) were recorded per animal, at each observation time.
Echocardiography (ECHO) for non-invasive assessment of cardiac function and structure. Standard ECHO was performed on surviving genotypes at 9 months. All ECHO examinations and analysis were performed by a skilled sonographer (S.H) blinded to treatment, as previously described19 (link)21 (link). Briefly; a Vivid 7 ultrasound machine (General Electric, Waukesha, WI) with a GE Vivid 7 10S transducer was used to collect ECHO data. Images were taken at a depth of 2–2.5 cm of the parasternal short-axis left ventricular view, using the papillary muscles as anatomical landmarks. Images were then exported to a separate workstation for analysis using EchoPAC (General Electric, Waukesha WI).
Echocardiography (ECHO) for non-invasive assessment of cardiac function and structure. Standard ECHO was performed on surviving genotypes at 9 months. All ECHO examinations and analysis were performed by a skilled sonographer (S.H) blinded to treatment, as previously described19 (link)21 (link). Briefly; a Vivid 7 ultrasound machine (General Electric, Waukesha, WI) with a GE Vivid 7 10S transducer was used to collect ECHO data. Images were taken at a depth of 2–2.5 cm of the parasternal short-axis left ventricular view, using the papillary muscles as anatomical landmarks. Images were then exported to a separate workstation for analysis using EchoPAC (General Electric, Waukesha WI).