**5. Fibertransformation preserving non-fatiguable Typ IIa fibers**

In our experience muscular blood pumps that were active over several months, were highly vulnerable when totally transformed into type I muscle showing severe muscle damage and decreased function. Thus, in our new experimental setting, encouraged by the Liverpool findings of the working group of Salmons and Jarvis [10], fast and fatigue resistant muscle ventricles were performed around the Frog. Pre-stimulation with about 2 Hz proceeded in situ, to open intramuscular collaterals connecting the proximal with the distal blood supply of the muscle and to increase capillary density. Thereafter we used continuous basic burst stimulation with an average pulses frequency of less than 1 Hz. Intermittent series of pumping within the Frog were performed, measuring pumping capacity in correlation to stimulation frequency. This procedure should be a "model setting" for a pumping on demand. During our first investigations, we could see that intermittent pumping capacity was already manifold after 4 to 5 months of pumping (Figure 8).

**Figure 8.** Daily energy of goat A (lower curve) with a mean pulse frequency of 5 Hz, which is massively declined. With 1 Hz stimulation in goat B however (upper curve) a high pumping capacity was observed.

Mean electrical pulse frequency with 5 Hz of group A (n=6) in Fig.9 resulted in a non relevant delivery of daily energy after 200 days of pumping. A 1 Hz stimulation of group B however showed an enhancing pressure and stroke volume and an increasing development of daily energy after 200 days with a well preserved muscular tissue.

Gel electrophoresis for myosin heavy chains MHC I and MHC IIa analysis (Figure 10) of group A with a mean pulse frequency of 5Hz showed a composition of MHC I (bottom of the gel) and MHC IIa (top of the gel) with mainly MHC IIa in the controls (C). In the trained SMVs (T) of group A was 100% MHC-I in all cases. In group B and with 1 Hz stimulation over months MHCIIa was preserved (50% MHC-IIa and 50% MHC-I). The preservation of Type II MHC in group B explains the more powerful contractions and the maintained pressure, stroke volume and daily energy (Figure 9).

Functional analysis of SMVs over more than 6 months of electrical stimulation

situ, to open intramuscular collaterals connecting the proximal with the distal blood supply of the muscle and to increase capillary density. Thereafter we used continuous basic burst stimulation with an average pulses frequency of less than 1 Hz. Intermittent series of pumping within the Frog were performed, measuring pumping capacity in correlation to stimulation frequency. This procedure should be a "model setting" for a pumping on demand. During our first investigations, we could see that intermittent pumping capacity was already manifold

**Figure 8.** Daily energy of goat A (lower curve) with a mean pulse frequency of 5 Hz, which is massively declined. With

Mean electrical pulse frequency with 5 Hz of group A (n=6) in Fig.9 resulted in a non relevant delivery of daily energy after 200 days of pumping. A 1 Hz stimulation of group B however showed an enhancing pressure and stroke volume and an increasing development of daily

Gel electrophoresis for myosin heavy chains MHC I and MHC IIa analysis (Figure 10) of group A with a mean pulse frequency of 5Hz showed a composition of MHC I (bottom of the gel) and MHC IIa (top of the gel) with mainly MHC IIa in the controls (C). In the trained SMVs (T) of group A was 100% MHC-I in all cases. In group B and with 1 Hz stimulation over months MHCIIa was preserved (50% MHC-IIa and 50% MHC-I). The preservation of Type II MHC in group B explains the more powerful contractions and the maintained pressure, stroke volume

1 Hz stimulation in goat B however (upper curve) a high pumping capacity was observed.

energy after 200 days with a well preserved muscular tissue.

and daily energy (Figure 9).

after 4 to 5 months of pumping (Figure 8).

348 Regenerative Medicine and Tissue Engineering

(n=6) with a mean pulse frequency of 5Hz (left) and with 1 Hz in group B (n=6, right) **Figure 9.** Systolic pressure (top),stroke volume (middle) and daily energy (bottom) of group A (n=6) with a mean pulse frequency of 5 Hz (left) and with 1 Hz in group B (n=6, right).

Mean electrical pulse frequency with 5 Hz of group A (n=6) in Fig.9 resulted in a non relevant delivery of daily energy after 200 days of pumping. A 1 Hz stimulation of group B however showed an enhancing pressure and stroke volume and an increasing development

of daily energy after 200 days with a well preserved muscular tissue.

Figure 9. Systolic pressure (top),stroke volume (middle) and daily energy(bottom) of group A

7

**Figure 10.** Gel electrophoresis of myosin heavy chains MHC I and MHC IIa from group A with a mean pulse frequency of 5 Hz. Control (C) was the non stimulated contra-lateral LDM. In group B with a mean stimulation frequency of 1 Hz, type IIa MHC is well preserved and about 50% after several months in all stimulated SMVs.
