Proteomics and Stem Cell Therapy as a New Vascularization Strategy

Neovascularization (NV) is the innate capability to enlarge collateral arteries ("arteriogenesis"), and to stimulate growth of new capillaries, arterioles and venules at the tissue level ("angiogenesis"). Patients with Chronic Limb-threatening Ischemia (CLI) present with forefoot rest-pain, ulceration and/or gangrene. They require risky and costly revascularization operations to avoid amputation. The investigators hypothesize that their inadequate NV can be modulated to restore this capability. By correcting impediments to NV in an out-patient setting, the investigators expect to facilitate CLI management. While the following impediments to NV are complex, the solution is not. Arteriogenesis necessitates endothelial cell activation in small collaterals as blood is offloaded away from the occluded artery. Shear stress provides this stimulus, but is attenuated caudal to multi-level arterial occlusive disease. The "arteriogenesis switch" is not turned on. Furthermore, the lack of nutritive oxygenated blood inflow and the accumulation of toxic metabolic by-products are adverse to synthetic pathways in the ischemic tissue. Additionally, protein "distress" signals cannot be effectively disseminated by the ischemic tissue, and the reparative progenitor cells they are supposed to mobilize cannot effectively home back to the ischemic tissue to orchestrate NV. The CLI patient is especially disadvantaged by having diminished function and number of circulating progenitor cells (CPC). Lastly these elderly, often diabetic, patients are less able to fend off infection. An FDA approved external programmed pneumatic compression device (PPCD) was used to restore the shear stress stimulus required for arteriogenesis. It also enhances oxygenated nutritive arterial inflow, clears waste products of metabolism (increased venous and lymphatic outflow), and helps distress proteins reach the central circulation and mobilized progenitor cells to return to the ischemic tissue. We corrected the progenitor cell and immunologic impairment with granulocyte colony stimulating factor (G-CSF), FDA approved for stem cell mobilization and immunological boost in the setting of cancer chemotherapy. The preliminary data show clinical, angiographic, hemodynamic and biochemical evidence for enhanced NV. The purpose for this study is to enroll 25 patients to reproduce the biochemical data to support a large scale clinical trial.