Therapeutic Neovascularization Using Cord Blood–Derived Endothelial Progenitor Cells for Diabetic Neuropathy

Abstract

Diabetic neuropathy is based on the impairment of nerve blood flow and the metabolic disorder. Although the vasodilating agents and anticoagulants improve nerve function and symptoms in diabetic neuropathy, more effective treatments are needed. Because endothelial progenitor cells (EPCs) have been identified in adult human peripheral blood, many studies have shown that transplantation of EPCs improves circulation to ischemic tissues. In this study, we have demonstrated that therapeutic neovascularization using human umbilical cord blood-derived EPCs reversed diabetic neuropathy. EPCs were isolated and expanded on day 7 of culture from cord blood mononuclear cells. Unilateral intramuscular injection of EPCs into hindlimb skeletal muscles significantly ameliorated impaired sciatic motor nerve conduction velocity and sciatic nerve blood flow in the EPC-injected side of streptozotocin-induced diabetic nude rats compared with the saline-injected side of diabetic nude rats. Histological study revealed an increased number of microvessels in hindlimb skeletal muscles in the EPC-injected side of diabetic rats. These findings suggest that transplantation of EPCs from cord blood may be a useful treatment for diabetic neuropathy.

Transplantation of Bone Marrow–Derived Mesenchymal Stem Cells Improves Diabetic Polyneuropathy in Rats

“…This notion is clinically and experimentally supported by various studies, which reported that the amelioration of NBF by various treatments improved impaired nerve functions (16,17,(33)(34)(35)(36)(37)(38)(39)(40). The beneficial effects of MSC transplantation on NCV and NBF in this study could be comparable with those of the therapeutic modalities reported previously.…”

“…The level of therapeutic vasculogenesis induced by MSC transplantation was similar to that by endothelial progenitor cell transplantation, as we previously reported (16), and the differentiation or incorporation of MSCs to vessels was not observed, suggesting that neovasculalization induced by transplantation would be mediated through the actions of angiogenic factors such as VEGF and bFGF secreted from MSCs, which would explain the improvement of NBF. In addition, both VEGF and bFGF have been reported to induce endothelial nitric oxide synthase (eNOS) production and to increase local blood flow through vasodilatation.…”

“…The sections of soleus muscles fixed with paraformaldehyde were used for hematoxylin-eosin staining and immunostaining. These stainings were performed as previously described in detail (16). The vascular capillaries were stained by anti-von Willebrand factor polyclonal antibody (1:600; Dako, Tokyo, Japan) and were counted under light microscopy (ϫ200) to determine the capillary number-to-muscle fiber ratio.…”

“…NBF. After evaluation of the MNCV, sciatic NBF (SNBF) was measured by the hydrogen clearance technique with an analog recorder (BW-4; Biochemical Science, Kanazawa, Japan) and an electrolysis tissue blood flow meter (RBA-2; Biochemical Science), as previously described (5,16,17), and calculated with the equation of Koshu et al (18). During this measurement, rats were placed on a heated pad in a room maintained at 25°C to ensure a constant rectal temperature of 37°C.…”

“…After intraperitoneal injection of sodium pentobarbital (5 mg/100 g), rats were placed on a heated pad in a room maintained at 25°C to ensure a constant rectal temperature of 37°C. The sciatic-tibial MNCV between the ankle and sciatic notch was determined with a Neuropak NEM-3102 instrument (Nihon-Koden, Osaka, Japan), as previously described (5,16,17). NBF.…”