**4. Clenbuterol supported dynamic training of skeletal muscle ventricles against systemic load**

The profound loss of power that occurs in skeletal muscle after electrical conditioning has been the major limiting factor in its clinical application. This study investigates a 3-fold approach for chronic conditioning of skeletal muscle ventricles combining electrical transformation, dynamic training against systemic load and pharmacological support with clenbuterol.

In 10 adult male goats, SMVs were constructed from latissimus dorsi wrapped around an intrathoracic training device with windkessel characteristics [8]. SMVs were stimulated electrically and trained dynamically by shifting volume against systemic load. Group 1 goats were controls (n=5), and group 2 goats (n=5) were supported with clenbuterol (150μg 3 times a week).

Peak pressure, stroke volume and stroke work per day were significantly improved (p< 0.007) in the clebuterol- treated group after 151±2.7 days (Fig. 6). At termination, myosin heavy chains were totally transformed into myosin heavy chain-I in all SMVs. Other investigators found different functional and histological effects of clenbuterol in dogs [9].

**Figure 6.** Time course of systolic pressure (top), stroke volume (middle), and power per day ( bottom) during dynamic training of SMVs without Clenbuterol n=5 (left) and supported by clenbuterol n=5 (right) against load conditions of 60 to 70 mm Hg [8].

were totally transformed into myosin heavy chain-I in all SMVs. Other investigators found

**Figure 6.** Time course of systolic pressure (top), stroke volume (middle), and power per day ( bottom) during dynamic training of SMVs without Clenbuterol n=5 (left) and supported by clenbuterol n=5 (right) against load conditions of 60 to

70 mm Hg [8].

different functional and histological effects of clenbuterol in dogs [9].

346 Regenerative Medicine and Tissue Engineering

**Figure 7.** Cross-section areas of clenbuterol treated (β-2-stimulated) muscle fibers were enhanced by 59%.
