Noninvasive augmentation of microvessel number in patients with peripheral vascular disease. (2003)

Abstract
OBJECTIVE:
Therapeutic angiogenesis has great potential for the treatment of ischemic diseases. One possible route for noninvasive induction of microvessels has recently been suggested by the finding that subcontractile electrical stimulation induces increased vascularization in animals. The present study tests the ability of such stimulation to augment microvessel number in patients with peripheral vascular disease.
DESIGN OF STUDY:
Overall, 36 patients were randomly assigned to control (n = 12) and treatment (n = 24) groups. Patients in the treatment group received localized subcontractile electrical stimulation on the feet of their ischemic limbs for three 60-minute periods each day over a 6-week period. Microvessel density was determined by capillary microscopy before treatment, at 3 and 6 weeks during treatment, and 4 weeks after completion. Transcutaneous oxygen tension was also determined at this site.
RESULTS:
Microvessel density determined by capillary microscopy was significantly increased (1.25-fold, P <.005) during and after treatment in patients receiving electrical stimulation. Transcutaneous oxygen tension was similarly increased in the treated patients (1.24-fold, P <.05). No changes were observed in these parameters in untreated patients examined in parallel.
CONCLUSION:
Localized subcontractile electrical stimulation can increase microvessel density and tissue perfusion in patients with peripheral vascular disease.

My comments:

Interesting paper that certainly has likely has implications for how electric stimulation helps with peripheral vascular disease and intermittent claudication. The intensity was low in this study at 10 mA, at 8 Hz, with a 5×5 cm electrodes applied 3 times, 1 hour per day, every day for 6 weeks which is pretty light but with a fairly long application time. As the abstract shows microvessel density improved substantially as did oxygenation of the tissues. However tissue samples were taken directly adjacent the region of the electrodes so it is hard to know if such low level stimulation reaches deeper into muscle tissue which might be necessary to improve such conditions as intermittent claudication. The researchers thought the mechanism of action was due to electric stimulation increasing various growth factors including vascular endothelial growth factor (VEGF) and IGF-II.