Background
Therapy with mesenchymal stem cells remains a promising but challenging approach to
critical limb ischemia in diabetes because of the dismal cell survival. Methods and Results
Critical limb ischemia in
type 2 diabetes mouse model was used to explore the impact of diabetic limb
ischemia on the survival of bone marrow mesenchymal stromal cells (bMSCs). Inhibition of intracellular
reactive oxygen species was achieved with concomitant overexpression of
superoxide dismutase (SOD)-1 and
glutathione peroxidase-1 in the transplanted bMSCs, and extracellular
reactive oxygen species was attenuated using SOD-3 overexpression and
N-acetylcysteine treatment. In vivo optical fluorescence imaging and
laser Doppler perfusion imaging were used to track cell retention and determine blood flow in diabetic ischemic limb, respectively. Survival of the transplanted bMSCs was significantly decreased in diabetic ischemic limb compared with the control. In vitro study indicated that
advanced glycation end products, not high
glucose, significantly decreased the proliferation of bMSCs and increased their apoptosis associated with increased
reactive oxygen species production and selective reduction of SOD-1 and SOD-3. In vivo study demonstrated that concomitant overexpression of SOD-1, SOD-3, and
glutathione peroxidase-1, or host treatment with
N-acetylcysteine, significantly enhanced in vivo survival of transplanted bMSCs, and improved
critical limb ischemia in diabetic mice. Combination of triple
antioxidant enzyme overexpression in bMSCs with host
N-acetylcysteine treatment further improved bMSC survival with enhanced circulatory and functional recovery from diabetic
critical limb ischemia. Conclusions Simultaneous suppression of
reactive oxygen species from transplanted bMSCs and host tissue could additively enhance bMSC survival in diabetic ischemic limb with increased therapeutic efficacy in diabetes.